#section-2 — Public Fediverse posts
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#BoilerManual #CycloneDescription #Section5 #Page13
cyclone furnace are shown by the rosin rammler plot in Figure 7. {Rosin-Rammler Distribution in this case is in reference to the math regarding particle comminution--powder--distribution.}Adhering to the recommended coal sizing will minimize erosion of various components of the cyclone. Wear block erosion in the radial burner can be slowed and coal flow remain uniform if wear block integrity is maintained.
Coal particle size is also an influencing factor in combustion. Large coal particles will be retained in the cyclone for a longer period of time while it is being scrubbed by the secondary air to complete combustion. This retention time, besides delaying complete combustion, delays liquefying of the coal ash into slag. This may lead to slag tapping problems.
Slag condition should be observed periodically through inspection doors to make sure that the slag is flowing from the cyclone and primary furnace tap holes. Slag which does not flow freely can indicate the following conditions: high excess air, low cyclone coal input, coal with a high ash fusion temperature, coarse coal, or low boiler load. Simply stated, the heat being generated in the cyclone and furnace is not always sufficient to cause the coal ash to liquify into slag form.
The satisfactory combustion of coal depends on the formation of a liquid slag layer in the cyclone. Ash is removed from the cyclone and primary furnace in fluid form. The viscosity of the slag must permit a slag flow at temperatures experienced in the cyclone and primary furnace. For fuels with high moisture contents and/or low heating values, it is desirable that the coal ash slag be less viscuous (will flow at a lower temperature).
Adjustments are made to the primary and tertiary air dampers only when wide variations in coal quality occurs. Normally, these dampers are set during the startup period and left in the same position for all loads. Lmiting guides for primary and tertiary air dampers are cyclone tapping, coal carrying over to main furnace and burner wear block temperature.
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#BoilerManual #CycloneDescription #Section5 #Page13
cyclone furnace are shown by the rosin rammler plot in Figure 7. {Rosin-Rammler Distribution in this case is in reference to the math regarding particle comminution--powder--distribution.}Adhering to the recommended coal sizing will minimize erosion of various components of the cyclone. Wear block erosion in the radial burner can be slowed and coal flow remain uniform if wear block integrity is maintained.
Coal particle size is also an influencing factor in combustion. Large coal particles will be retained in the cyclone for a longer period of time while it is being scrubbed by the secondary air to complete combustion. This retention time, besides delaying complete combustion, delays liquefying of the coal ash into slag. This may lead to slag tapping problems.
Slag condition should be observed periodically through inspection doors to make sure that the slag is flowing from the cyclone and primary furnace tap holes. Slag which does not flow freely can indicate the following conditions: high excess air, low cyclone coal input, coal with a high ash fusion temperature, coarse coal, or low boiler load. Simply stated, the heat being generated in the cyclone and furnace is not always sufficient to cause the coal ash to liquify into slag form.
The satisfactory combustion of coal depends on the formation of a liquid slag layer in the cyclone. Ash is removed from the cyclone and primary furnace in fluid form. The viscosity of the slag must permit a slag flow at temperatures experienced in the cyclone and primary furnace. For fuels with high moisture contents and/or low heating values, it is desirable that the coal ash slag be less viscuous (will flow at a lower temperature).
Adjustments are made to the primary and tertiary air dampers only when wide variations in coal quality occurs. Normally, these dampers are set during the startup period and left in the same position for all loads. Lmiting guides for primary and tertiary air dampers are cyclone tapping, coal carrying over to main furnace and burner wear block temperature.
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#BoilerManual #CycloneDescription #Section5 #Page13
cyclone furnace are shown by the rosin rammler plot in Figure 7. {Rosin-Rammler Distribution in this case is in reference to the math regarding particle comminution--powder--distribution.}Adhering to the recommended coal sizing will minimize erosion of various components of the cyclone. Wear block erosion in the radial burner can be slowed and coal flow remain uniform if wear block integrity is maintained.
Coal particle size is also an influencing factor in combustion. Large coal particles will be retained in the cyclone for a longer period of time while it is being scrubbed by the secondary air to complete combustion. This retention time, besides delaying complete combustion, delays liquefying of the coal ash into slag. This may lead to slag tapping problems.
Slag condition should be observed periodically through inspection doors to make sure that the slag is flowing from the cyclone and primary furnace tap holes. Slag which does not flow freely can indicate the following conditions: high excess air, low cyclone coal input, coal with a high ash fusion temperature, coarse coal, or low boiler load. Simply stated, the heat being generated in the cyclone and furnace is not always sufficient to cause the coal ash to liquify into slag form.
The satisfactory combustion of coal depends on the formation of a liquid slag layer in the cyclone. Ash is removed from the cyclone and primary furnace in fluid form. The viscosity of the slag must permit a slag flow at temperatures experienced in the cyclone and primary furnace. For fuels with high moisture contents and/or low heating values, it is desirable that the coal ash slag be less viscuous (will flow at a lower temperature).
Adjustments are made to the primary and tertiary air dampers only when wide variations in coal quality occurs. Normally, these dampers are set during the startup period and left in the same position for all loads. Lmiting guides for primary and tertiary air dampers are cyclone tapping, coal carrying over to main furnace and burner wear block temperature.
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#BoilerManual #CycloneDescription #Section5 #Page13
cyclone furnace are shown by the rosin rammler plot in Figure 7. {Rosin-Rammler Distribution in this case is in reference to the math regarding particle comminution--powder--distribution.}Adhering to the recommended coal sizing will minimize erosion of various components of the cyclone. Wear block erosion in the radial burner can be slowed and coal flow remain uniform if wear block integrity is maintained.
Coal particle size is also an influencing factor in combustion. Large coal particles will be retained in the cyclone for a longer period of time while it is being scrubbed by the secondary air to complete combustion. This retention time, besides delaying complete combustion, delays liquefying of the coal ash into slag. This may lead to slag tapping problems.
Slag condition should be observed periodically through inspection doors to make sure that the slag is flowing from the cyclone and primary furnace tap holes. Slag which does not flow freely can indicate the following conditions: high excess air, low cyclone coal input, coal with a high ash fusion temperature, coarse coal, or low boiler load. Simply stated, the heat being generated in the cyclone and furnace is not always sufficient to cause the coal ash to liquify into slag form.
The satisfactory combustion of coal depends on the formation of a liquid slag layer in the cyclone. Ash is removed from the cyclone and primary furnace in fluid form. The viscosity of the slag must permit a slag flow at temperatures experienced in the cyclone and primary furnace. For fuels with high moisture contents and/or low heating values, it is desirable that the coal ash slag be less viscuous (will flow at a lower temperature).
Adjustments are made to the primary and tertiary air dampers only when wide variations in coal quality occurs. Normally, these dampers are set during the startup period and left in the same position for all loads. Lmiting guides for primary and tertiary air dampers are cyclone tapping, coal carrying over to main furnace and burner wear block temperature.
------------------------------------------------- 13 ------------------------------------------------------
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#BoilerManual #CycloneDescription #Section5 #Page13
cyclone furnace are shown by the rosin rammler plot in Figure 7. {Rosin-Rammler Distribution in this case is in reference to the math regarding particle comminution--powder--distribution.}Adhering to the recommended coal sizing will minimize erosion of various components of the cyclone. Wear block erosion in the radial burner can be slowed and coal flow remain uniform if wear block integrity is maintained.
Coal particle size is also an influencing factor in combustion. Large coal particles will be retained in the cyclone for a longer period of time while it is being scrubbed by the secondary air to complete combustion. This retention time, besides delaying complete combustion, delays liquefying of the coal ash into slag. This may lead to slag tapping problems.
Slag condition should be observed periodically through inspection doors to make sure that the slag is flowing from the cyclone and primary furnace tap holes. Slag which does not flow freely can indicate the following conditions: high excess air, low cyclone coal input, coal with a high ash fusion temperature, coarse coal, or low boiler load. Simply stated, the heat being generated in the cyclone and furnace is not always sufficient to cause the coal ash to liquify into slag form.
The satisfactory combustion of coal depends on the formation of a liquid slag layer in the cyclone. Ash is removed from the cyclone and primary furnace in fluid form. The viscosity of the slag must permit a slag flow at temperatures experienced in the cyclone and primary furnace. For fuels with high moisture contents and/or low heating values, it is desirable that the coal ash slag be less viscuous (will flow at a lower temperature).
Adjustments are made to the primary and tertiary air dampers only when wide variations in coal quality occurs. Normally, these dampers are set during the startup period and left in the same position for all loads. Lmiting guides for primary and tertiary air dampers are cyclone tapping, coal carrying over to main furnace and burner wear block temperature.
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#BoilerManual #CycloneDescription #Section5 #Page12
which in turn determines the amount of heat available in the air heater to be transferred to the incoming secondary air.
Air heater pluggage will inhibit the heat transfer between the incoming secondary air and the outgoing flue gas. The result will be decreased secondary (combustion ) air temperature. Stack losses due to increased exit gas temperature will also result in decreased unit efficiency.
FUEL/AIR BALANCING
The feeder must supply fuel to the cyclone at a continuous and uniform rate of feed. The air flow to the cyclone is regulated to maintain the proper fuel/air relationship. Proper amounts of fuel and air are necessary because coal is burned at almost spontaneously when it reaches the cyclone furnace. Fluctuations in coal feed or air flow are reflected in boiler load and combustion conditions. The rapidity of combustion makes the cyclone furnace very responsive to load demand. Boiler output can be made to respond very quickly to load demand by changing coal feeder speed with a corresponding change in air flow.
Balanced cyclone loading can only be accomplished by balanced fuel/air feed rates. Feeder speeds and damper positions should be adjusted for identical maximum and minimum speeds at high and low boiler loads with all cyclones in service.
Minimum feeder speed stops should be set to proper cyclone excess air levels with minimum secondary air damper position (lightoff). Set to the proper excess air level at the lightoff position the cyclone loading will normally be greater than the minimum firing rate for which stable combustion or slag tapping conditions are maintained.
The recommended size distribution ranges of coals burned in the
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#BoilerManual #CycloneDescription #Section5 #Page12
which in turn determines the amount of heat available in the air heater to be transferred to the incoming secondary air.
Air heater pluggage will inhibit the heat transfer between the incoming secondary air and the outgoing flue gas. The result will be decreased secondary (combustion ) air temperature. Stack losses due to increased exit gas temperature will also result in decreased unit efficiency.
FUEL/AIR BALANCING
The feeder must supply fuel to the cyclone at a continuous and uniform rate of feed. The air flow to the cyclone is regulated to maintain the proper fuel/air relationship. Proper amounts of fuel and air are necessary because coal is burned at almost spontaneously when it reaches the cyclone furnace. Fluctuations in coal feed or air flow are reflected in boiler load and combustion conditions. The rapidity of combustion makes the cyclone furnace very responsive to load demand. Boiler output can be made to respond very quickly to load demand by changing coal feeder speed with a corresponding change in air flow.
Balanced cyclone loading can only be accomplished by balanced fuel/air feed rates. Feeder speeds and damper positions should be adjusted for identical maximum and minimum speeds at high and low boiler loads with all cyclones in service.
Minimum feeder speed stops should be set to proper cyclone excess air levels with minimum secondary air damper position (lightoff). Set to the proper excess air level at the lightoff position the cyclone loading will normally be greater than the minimum firing rate for which stable combustion or slag tapping conditions are maintained.
The recommended size distribution ranges of coals burned in the
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#BoilerManual #CycloneDescription #Section5 #Page12
which in turn determines the amount of heat available in the air heater to be transferred to the incoming secondary air.
Air heater pluggage will inhibit the heat transfer between the incoming secondary air and the outgoing flue gas. The result will be decreased secondary (combustion ) air temperature. Stack losses due to increased exit gas temperature will also result in decreased unit efficiency.
FUEL/AIR BALANCING
The feeder must supply fuel to the cyclone at a continuous and uniform rate of feed. The air flow to the cyclone is regulated to maintain the proper fuel/air relationship. Proper amounts of fuel and air are necessary because coal is burned at almost spontaneously when it reaches the cyclone furnace. Fluctuations in coal feed or air flow are reflected in boiler load and combustion conditions. The rapidity of combustion makes the cyclone furnace very responsive to load demand. Boiler output can be made to respond very quickly to load demand by changing coal feeder speed with a corresponding change in air flow.
Balanced cyclone loading can only be accomplished by balanced fuel/air feed rates. Feeder speeds and damper positions should be adjusted for identical maximum and minimum speeds at high and low boiler loads with all cyclones in service.
Minimum feeder speed stops should be set to proper cyclone excess air levels with minimum secondary air damper position (lightoff). Set to the proper excess air level at the lightoff position the cyclone loading will normally be greater than the minimum firing rate for which stable combustion or slag tapping conditions are maintained.
The recommended size distribution ranges of coals burned in the
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#BoilerManual #CycloneDescription #Section5 #Page12
which in turn determines the amount of heat available in the air heater to be transferred to the incoming secondary air.
Air heater pluggage will inhibit the heat transfer between the incoming secondary air and the outgoing flue gas. The result will be decreased secondary (combustion ) air temperature. Stack losses due to increased exit gas temperature will also result in decreased unit efficiency.
FUEL/AIR BALANCING
The feeder must supply fuel to the cyclone at a continuous and uniform rate of feed. The air flow to the cyclone is regulated to maintain the proper fuel/air relationship. Proper amounts of fuel and air are necessary because coal is burned at almost spontaneously when it reaches the cyclone furnace. Fluctuations in coal feed or air flow are reflected in boiler load and combustion conditions. The rapidity of combustion makes the cyclone furnace very responsive to load demand. Boiler output can be made to respond very quickly to load demand by changing coal feeder speed with a corresponding change in air flow.
Balanced cyclone loading can only be accomplished by balanced fuel/air feed rates. Feeder speeds and damper positions should be adjusted for identical maximum and minimum speeds at high and low boiler loads with all cyclones in service.
Minimum feeder speed stops should be set to proper cyclone excess air levels with minimum secondary air damper position (lightoff). Set to the proper excess air level at the lightoff position the cyclone loading will normally be greater than the minimum firing rate for which stable combustion or slag tapping conditions are maintained.
The recommended size distribution ranges of coals burned in the
------------------------------------------------- 12 ------------------------------------------------------
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#BoilerManual #CycloneDescription #Section5 #Page12
which in turn determines the amount of heat available in the air heater to be transferred to the incoming secondary air.
Air heater pluggage will inhibit the heat transfer between the incoming secondary air and the outgoing flue gas. The result will be decreased secondary (combustion ) air temperature. Stack losses due to increased exit gas temperature will also result in decreased unit efficiency.
FUEL/AIR BALANCING
The feeder must supply fuel to the cyclone at a continuous and uniform rate of feed. The air flow to the cyclone is regulated to maintain the proper fuel/air relationship. Proper amounts of fuel and air are necessary because coal is burned at almost spontaneously when it reaches the cyclone furnace. Fluctuations in coal feed or air flow are reflected in boiler load and combustion conditions. The rapidity of combustion makes the cyclone furnace very responsive to load demand. Boiler output can be made to respond very quickly to load demand by changing coal feeder speed with a corresponding change in air flow.
Balanced cyclone loading can only be accomplished by balanced fuel/air feed rates. Feeder speeds and damper positions should be adjusted for identical maximum and minimum speeds at high and low boiler loads with all cyclones in service.
Minimum feeder speed stops should be set to proper cyclone excess air levels with minimum secondary air damper position (lightoff). Set to the proper excess air level at the lightoff position the cyclone loading will normally be greater than the minimum firing rate for which stable combustion or slag tapping conditions are maintained.
The recommended size distribution ranges of coals burned in the
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#BoilerManual #CycloneDescription #Section5 #Page11
This assumes that a specific fuel and air combination will result in complete combustion while ignoring any heat loss to the surroundings. While this can never be achieved in actual operation, it is desirable to gear plant operations toward the goal of efficient and complete combustion. The benefits will be seen throughout the boiler system.
The heat of combustion (BTU value) of the fuel is the major factor which determines the flame temperature. This is a property inherent to the fuel and over which the operator has no control. However, other variables are controllable and will have the effect of raising the flame temperature. Increasing the temperature of the combustion air or fuel (reduce moisture) will increase flame temperature. The adiabatic flame temperature will be at a maximum with zero excess air (although some excess air is required to insure that all the fuel is burned). Excess air is not involved in the combustion process and only dilutes the temperature of the products of combustion.
The secondary (combustion) air temperature required depends greatly on the moisture content of the fuel and the boiler load. The greater the amount of moisture in the fuel, the higher the combustion air temperature required to dry the fuel. Similarly, high boiler loads require increased combustion air temperature to ensure self-sustaining combustion. In order to ensure adequate combustion over the entire load range, certain adjustments are required at windbox temperatures below 300 F. Primary and tertiary air is limited to minimum flow until the windbox temperature exceeds 300 F The lighter will remain in service for extra heat input and to stabilize ignition until the windbox temperature exceeds 300 F. Total air flow per cyclone also compensates for combustion air temperature (along with excess air) throughout the load range.
Other factors which affect secondary air temperature are sootblowing schedule or pattern, and air heater pluggage or leakage. Sootblowing patterns directly affect the flue gas temperature at the economizer outlet
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#BoilerManual #CycloneDescription #Section5 #Page11
This assumes that a specific fuel and air combination will result in complete combustion while ignoring any heat loss to the surroundings. While this can never be achieved in actual operation, it is desirable to gear plant operations toward the goal of efficient and complete combustion. The benefits will be seen throughout the boiler system.
The heat of combustion (BTU value) of the fuel is the major factor which determines the flame temperature. This is a property inherent to the fuel and over which the operator has no control. However, other variables are controllable and will have the effect of raising the flame temperature. Increasing the temperature of the combustion air or fuel (reduce moisture) will increase flame temperature. The adiabatic flame temperature will be at a maximum with zero excess air (although some excess air is required to insure that all the fuel is burned). Excess air is not involved in the combustion process and only dilutes the temperature of the products of combustion.
The secondary (combustion) air temperature required depends greatly on the moisture content of the fuel and the boiler load. The greater the amount of moisture in the fuel, the higher the combustion air temperature required to dry the fuel. Similarly, high boiler loads require increased combustion air temperature to ensure self-sustaining combustion. In order to ensure adequate combustion over the entire load range, certain adjustments are required at windbox temperatures below 300 F. Primary and tertiary air is limited to minimum flow until the windbox temperature exceeds 300 F The lighter will remain in service for extra heat input and to stabilize ignition until the windbox temperature exceeds 300 F. Total air flow per cyclone also compensates for combustion air temperature (along with excess air) throughout the load range.
Other factors which affect secondary air temperature are sootblowing schedule or pattern, and air heater pluggage or leakage. Sootblowing patterns directly affect the flue gas temperature at the economizer outlet
------------------------------------------------- 11 ------------------------------------------------------
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#BoilerManual #CycloneDescription #Section5 #Page11
This assumes that a specific fuel and air combination will result in complete combustion while ignoring any heat loss to the surroundings. While this can never be achieved in actual operation, it is desirable to gear plant operations toward the goal of efficient and complete combustion. The benefits will be seen throughout the boiler system.
The heat of combustion (BTU value) of the fuel is the major factor which determines the flame temperature. This is a property inherent to the fuel and over which the operator has no control. However, other variables are controllable and will have the effect of raising the flame temperature. Increasing the temperature of the combustion air or fuel (reduce moisture) will increase flame temperature. The adiabatic flame temperature will be at a maximum with zero excess air (although some excess air is required to insure that all the fuel is burned). Excess air is not involved in the combustion process and only dilutes the temperature of the products of combustion.
The secondary (combustion) air temperature required depends greatly on the moisture content of the fuel and the boiler load. The greater the amount of moisture in the fuel, the higher the combustion air temperature required to dry the fuel. Similarly, high boiler loads require increased combustion air temperature to ensure self-sustaining combustion. In order to ensure adequate combustion over the entire load range, certain adjustments are required at windbox temperatures below 300 F. Primary and tertiary air is limited to minimum flow until the windbox temperature exceeds 300 F The lighter will remain in service for extra heat input and to stabilize ignition until the windbox temperature exceeds 300 F. Total air flow per cyclone also compensates for combustion air temperature (along with excess air) throughout the load range.
Other factors which affect secondary air temperature are sootblowing schedule or pattern, and air heater pluggage or leakage. Sootblowing patterns directly affect the flue gas temperature at the economizer outlet
------------------------------------------------- 11 ------------------------------------------------------
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#BoilerManual #CycloneDescription #Section5 #Page11
This assumes that a specific fuel and air combination will result in complete combustion while ignoring any heat loss to the surroundings. While this can never be achieved in actual operation, it is desirable to gear plant operations toward the goal of efficient and complete combustion. The benefits will be seen throughout the boiler system.
The heat of combustion (BTU value) of the fuel is the major factor which determines the flame temperature. This is a property inherent to the fuel and over which the operator has no control. However, other variables are controllable and will have the effect of raising the flame temperature. Increasing the temperature of the combustion air or fuel (reduce moisture) will increase flame temperature. The adiabatic flame temperature will be at a maximum with zero excess air (although some excess air is required to insure that all the fuel is burned). Excess air is not involved in the combustion process and only dilutes the temperature of the products of combustion.
The secondary (combustion) air temperature required depends greatly on the moisture content of the fuel and the boiler load. The greater the amount of moisture in the fuel, the higher the combustion air temperature required to dry the fuel. Similarly, high boiler loads require increased combustion air temperature to ensure self-sustaining combustion. In order to ensure adequate combustion over the entire load range, certain adjustments are required at windbox temperatures below 300 F. Primary and tertiary air is limited to minimum flow until the windbox temperature exceeds 300 F The lighter will remain in service for extra heat input and to stabilize ignition until the windbox temperature exceeds 300 F. Total air flow per cyclone also compensates for combustion air temperature (along with excess air) throughout the load range.
Other factors which affect secondary air temperature are sootblowing schedule or pattern, and air heater pluggage or leakage. Sootblowing patterns directly affect the flue gas temperature at the economizer outlet
------------------------------------------------- 11 ------------------------------------------------------
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#BoilerManual #CycloneDescription #Section5 #Page11
This assumes that a specific fuel and air combination will result in complete combustion while ignoring any heat loss to the surroundings. While this can never be achieved in actual operation, it is desirable to gear plant operations toward the goal of efficient and complete combustion. The benefits will be seen throughout the boiler system.
The heat of combustion (BTU value) of the fuel is the major factor which determines the flame temperature. This is a property inherent to the fuel and over which the operator has no control. However, other variables are controllable and will have the effect of raising the flame temperature. Increasing the temperature of the combustion air or fuel (reduce moisture) will increase flame temperature. The adiabatic flame temperature will be at a maximum with zero excess air (although some excess air is required to insure that all the fuel is burned). Excess air is not involved in the combustion process and only dilutes the temperature of the products of combustion.
The secondary (combustion) air temperature required depends greatly on the moisture content of the fuel and the boiler load. The greater the amount of moisture in the fuel, the higher the combustion air temperature required to dry the fuel. Similarly, high boiler loads require increased combustion air temperature to ensure self-sustaining combustion. In order to ensure adequate combustion over the entire load range, certain adjustments are required at windbox temperatures below 300 F. Primary and tertiary air is limited to minimum flow until the windbox temperature exceeds 300 F The lighter will remain in service for extra heat input and to stabilize ignition until the windbox temperature exceeds 300 F. Total air flow per cyclone also compensates for combustion air temperature (along with excess air) throughout the load range.
Other factors which affect secondary air temperature are sootblowing schedule or pattern, and air heater pluggage or leakage. Sootblowing patterns directly affect the flue gas temperature at the economizer outlet
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#BoilerManual #CycloneDescription #Section5 #Page10
when more heat is generated by the combustion process than is lost to the surroundings.
The ignition temperature of coal may be considered to be the ignition temperature of its fixed carbon content. The gaseous constituents of coal are usually distilled off, but not ignited, prior to reaching the ignition temperature. It is the process of distilling off the gaseous constituents in the fuel which delays combustion.
Delayed combustion can result in many adverse effects in cyclone performance and general unit operation. Many factors contribute to inefficient operation fo the unit, whether it be fuel quality of preparation, air quantity or temperature, or general boiler operation.
Normally, operation for extended periods of time at loads below one-half of normal cyclone rating can result in a frozen slag tap. During low load operation, it is generally advisable to operate fewer cyclones at a higher loading. If the load were to be distributed to all cyclones, the limited heat input would not be sufficient to insure adequate slag tapping in any of the cyclones.
Regardless of the number of cyclones in-service, equal fuel and air input to each cyclone is recommended to help maintain event heat distribution to the boiler. This will help maintain the correct fuel/air ratio and insure that individual cyclone loading is maintained within design limits.
In most cases, the cyclone can handle loads greater than its design rating. However, operating at higher than design loads is not recommended because of the high localized heat input to the cyclone and furnace wall tubes.
The maximum theoretical temperature which can be reached by the products of combustion is known as the adiabatic flame temperature.
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#BoilerManual #CycloneDescription #Section5 #Page10
when more heat is generated by the combustion process than is lost to the surroundings.
The ignition temperature of coal may be considered to be the ignition temperature of its fixed carbon content. The gaseous constituents of coal are usually distilled off, but not ignited, prior to reaching the ignition temperature. It is the process of distilling off the gaseous constituents in the fuel which delays combustion.
Delayed combustion can result in many adverse effects in cyclone performance and general unit operation. Many factors contribute to inefficient operation fo the unit, whether it be fuel quality of preparation, air quantity or temperature, or general boiler operation.
Normally, operation for extended periods of time at loads below one-half of normal cyclone rating can result in a frozen slag tap. During low load operation, it is generally advisable to operate fewer cyclones at a higher loading. If the load were to be distributed to all cyclones, the limited heat input would not be sufficient to insure adequate slag tapping in any of the cyclones.
Regardless of the number of cyclones in-service, equal fuel and air input to each cyclone is recommended to help maintain event heat distribution to the boiler. This will help maintain the correct fuel/air ratio and insure that individual cyclone loading is maintained within design limits.
In most cases, the cyclone can handle loads greater than its design rating. However, operating at higher than design loads is not recommended because of the high localized heat input to the cyclone and furnace wall tubes.
The maximum theoretical temperature which can be reached by the products of combustion is known as the adiabatic flame temperature.
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#BoilerManual #CycloneDescription #Section5 #Page10
when more heat is generated by the combustion process than is lost to the surroundings.
The ignition temperature of coal may be considered to be the ignition temperature of its fixed carbon content. The gaseous constituents of coal are usually distilled off, but not ignited, prior to reaching the ignition temperature. It is the process of distilling off the gaseous constituents in the fuel which delays combustion.
Delayed combustion can result in many adverse effects in cyclone performance and general unit operation. Many factors contribute to inefficient operation fo the unit, whether it be fuel quality of preparation, air quantity or temperature, or general boiler operation.
Normally, operation for extended periods of time at loads below one-half of normal cyclone rating can result in a frozen slag tap. During low load operation, it is generally advisable to operate fewer cyclones at a higher loading. If the load were to be distributed to all cyclones, the limited heat input would not be sufficient to insure adequate slag tapping in any of the cyclones.
Regardless of the number of cyclones in-service, equal fuel and air input to each cyclone is recommended to help maintain event heat distribution to the boiler. This will help maintain the correct fuel/air ratio and insure that individual cyclone loading is maintained within design limits.
In most cases, the cyclone can handle loads greater than its design rating. However, operating at higher than design loads is not recommended because of the high localized heat input to the cyclone and furnace wall tubes.
The maximum theoretical temperature which can be reached by the products of combustion is known as the adiabatic flame temperature.
------------------------------------------------- 10 ------------------------------------------------------
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#BoilerManual #CycloneDescription #Section5 #Page10
when more heat is generated by the combustion process than is lost to the surroundings.
The ignition temperature of coal may be considered to be the ignition temperature of its fixed carbon content. The gaseous constituents of coal are usually distilled off, but not ignited, prior to reaching the ignition temperature. It is the process of distilling off the gaseous constituents in the fuel which delays combustion.
Delayed combustion can result in many adverse effects in cyclone performance and general unit operation. Many factors contribute to inefficient operation fo the unit, whether it be fuel quality of preparation, air quantity or temperature, or general boiler operation.
Normally, operation for extended periods of time at loads below one-half of normal cyclone rating can result in a frozen slag tap. During low load operation, it is generally advisable to operate fewer cyclones at a higher loading. If the load were to be distributed to all cyclones, the limited heat input would not be sufficient to insure adequate slag tapping in any of the cyclones.
Regardless of the number of cyclones in-service, equal fuel and air input to each cyclone is recommended to help maintain event heat distribution to the boiler. This will help maintain the correct fuel/air ratio and insure that individual cyclone loading is maintained within design limits.
In most cases, the cyclone can handle loads greater than its design rating. However, operating at higher than design loads is not recommended because of the high localized heat input to the cyclone and furnace wall tubes.
The maximum theoretical temperature which can be reached by the products of combustion is known as the adiabatic flame temperature.
------------------------------------------------- 10 ------------------------------------------------------
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#BoilerManual #CycloneDescription #Section5 #Page10
when more heat is generated by the combustion process than is lost to the surroundings.
The ignition temperature of coal may be considered to be the ignition temperature of its fixed carbon content. The gaseous constituents of coal are usually distilled off, but not ignited, prior to reaching the ignition temperature. It is the process of distilling off the gaseous constituents in the fuel which delays combustion.
Delayed combustion can result in many adverse effects in cyclone performance and general unit operation. Many factors contribute to inefficient operation fo the unit, whether it be fuel quality of preparation, air quantity or temperature, or general boiler operation.
Normally, operation for extended periods of time at loads below one-half of normal cyclone rating can result in a frozen slag tap. During low load operation, it is generally advisable to operate fewer cyclones at a higher loading. If the load were to be distributed to all cyclones, the limited heat input would not be sufficient to insure adequate slag tapping in any of the cyclones.
Regardless of the number of cyclones in-service, equal fuel and air input to each cyclone is recommended to help maintain event heat distribution to the boiler. This will help maintain the correct fuel/air ratio and insure that individual cyclone loading is maintained within design limits.
In most cases, the cyclone can handle loads greater than its design rating. However, operating at higher than design loads is not recommended because of the high localized heat input to the cyclone and furnace wall tubes.
The maximum theoretical temperature which can be reached by the products of combustion is known as the adiabatic flame temperature.
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#BoilerManual #CycloneDescription #Section5 #Page9
The incoming coal particles (except for a few fines that are burned in suspension) are thrown to the walls by centrifugal force, held in the slag layer, then scrubbed by the high velocity secondary air. Thus, the air required to burn the coal is quickly supplied and the products of combustion are rapidly removed. High velocities are required in the cyclone to scrub the surface of the burning coal particles. This scrubbing action quickly removes the ash and supplies air to the surface of the fuel to further combustion.
The release of heat per cu. ft. in the cyclone furnace is very high. However, there is only a small amount of surface in the cyclone and this surface is partially insulated by the covering slag layer. This combination of high heat release and low heat absorption assures the high temperatures necessary to complete combustion and to provide the desired liquid slag covering in the cyclone.
The gaseous products of combustion are discharged through the water-cooled re-entrant throat of the cyclone, into the gas cooling boiler furnace. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away from the burner end and discharges through the slag tap to the boiler furnace. From the furnace, slag is tapped into a slag tank where it is solidified, and disintegrated for disposal. {Disposal at Baldwin consisted of flushing this "bottom ash" to an outside retention pond subjected to evaporation. In the later1980s, this bottom ash plus the precipitated "fly ash" were sold to pavement manufacturing companies to be used in their asphalt and concrete mixes for roadways.}
By this method of combustion, the fuel is burned quickly and completely in the small cyclone chamber, and the boiler furnace is used for cooling the flue gases. Most of the ash is retained as a liquid slag and tapped into the slag tank under the boiler furnace. Thus, the quantity of fly ash contained in the flue gas is low {even so, due to acid rain legislation, they also added scrubbers to the stacks}.
The objective of good cyclone operation is to promote rapid ignition which leads to a self-sustaining combustion process. The point at which this occurs is known as the ignition temperature. Ignition is sustained
-------------------------------------------------- 9 ------------------------------------------------------
-
#BoilerManual #CycloneDescription #Section5 #Page9
The incoming coal particles (except for a few fines that are burned in suspension) are thrown to the walls by centrifugal force, held in the slag layer, then scrubbed by the high velocity secondary air. Thus, the air required to burn the coal is quickly supplied and the products of combustion are rapidly removed. High velocities are required in the cyclone to scrub the surface of the burning coal particles. This scrubbing action quickly removes the ash and supplies air to the surface of the fuel to further combustion.
The release of heat per cu. ft. in the cyclone furnace is very high. However, there is only a small amount of surface in the cyclone and this surface is partially insulated by the covering slag layer. This combination of high heat release and low heat absorption assures the high temperatures necessary to complete combustion and to provide the desired liquid slag covering in the cyclone.
The gaseous products of combustion are discharged through the water-cooled re-entrant throat of the cyclone, into the gas cooling boiler furnace. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away from the burner end and discharges through the slag tap to the boiler furnace. From the furnace, slag is tapped into a slag tank where it is solidified, and disintegrated for disposal. {Disposal at Baldwin consisted of flushing this "bottom ash" to an outside retention pond subjected to evaporation. In the later1980s, this bottom ash plus the precipitated "fly ash" were sold to pavement manufacturing companies to be used in their asphalt and concrete mixes for roadways.}
By this method of combustion, the fuel is burned quickly and completely in the small cyclone chamber, and the boiler furnace is used for cooling the flue gases. Most of the ash is retained as a liquid slag and tapped into the slag tank under the boiler furnace. Thus, the quantity of fly ash contained in the flue gas is low {even so, due to acid rain legislation, they also added scrubbers to the stacks}.
The objective of good cyclone operation is to promote rapid ignition which leads to a self-sustaining combustion process. The point at which this occurs is known as the ignition temperature. Ignition is sustained
-------------------------------------------------- 9 ------------------------------------------------------
-
#BoilerManual #CycloneDescription #Section5 #Page9
The incoming coal particles (except for a few fines that are burned in suspension) are thrown to the walls by centrifugal force, held in the slag layer, then scrubbed by the high velocity secondary air. Thus, the air required to burn the coal is quickly supplied and the products of combustion are rapidly removed. High velocities are required in the cyclone to scrub the surface of the burning coal particles. This scrubbing action quickly removes the ash and supplies air to the surface of the fuel to further combustion.
The release of heat per cu. ft. in the cyclone furnace is very high. However, there is only a small amount of surface in the cyclone and this surface is partially insulated by the covering slag layer. This combination of high heat release and low heat absorption assures the high temperatures necessary to complete combustion and to provide the desired liquid slag covering in the cyclone.
The gaseous products of combustion are discharged through the water-cooled re-entrant throat of the cyclone, into the gas cooling boiler furnace. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away from the burner end and discharges through the slag tap to the boiler furnace. From the furnace, slag is tapped into a slag tank where it is solidified, and disintegrated for disposal. {Disposal at Baldwin consisted of flushing this "bottom ash" to an outside retention pond subjected to evaporation. In the later1980s, this bottom ash plus the precipitated "fly ash" were sold to pavement manufacturing companies to be used in their asphalt and concrete mixes for roadways.}
By this method of combustion, the fuel is burned quickly and completely in the small cyclone chamber, and the boiler furnace is used for cooling the flue gases. Most of the ash is retained as a liquid slag and tapped into the slag tank under the boiler furnace. Thus, the quantity of fly ash contained in the flue gas is low {even so, due to acid rain legislation, they also added scrubbers to the stacks}.
The objective of good cyclone operation is to promote rapid ignition which leads to a self-sustaining combustion process. The point at which this occurs is known as the ignition temperature. Ignition is sustained
-------------------------------------------------- 9 ------------------------------------------------------
-
#BoilerManual #CycloneDescription #Section5 #Page9
The incoming coal particles (except for a few fines that are burned in suspension) are thrown to the walls by centrifugal force, held in the slag layer, then scrubbed by the high velocity secondary air. Thus, the air required to burn the coal is quickly supplied and the products of combustion are rapidly removed. High velocities are required in the cyclone to scrub the surface of the burning coal particles. This scrubbing action quickly removes the ash and supplies air to the surface of the fuel to further combustion.
The release of heat per cu. ft. in the cyclone furnace is very high. However, there is only a small amount of surface in the cyclone and this surface is partially insulated by the covering slag layer. This combination of high heat release and low heat absorption assures the high temperatures necessary to complete combustion and to provide the desired liquid slag covering in the cyclone.
The gaseous products of combustion are discharged through the water-cooled re-entrant throat of the cyclone, into the gas cooling boiler furnace. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away from the burner end and discharges through the slag tap to the boiler furnace. From the furnace, slag is tapped into a slag tank where it is solidified, and disintegrated for disposal. {Disposal at Baldwin consisted of flushing this "bottom ash" to an outside retention pond subjected to evaporation. In the later1980s, this bottom ash plus the precipitated "fly ash" were sold to pavement manufacturing companies to be used in their asphalt and concrete mixes for roadways.}
By this method of combustion, the fuel is burned quickly and completely in the small cyclone chamber, and the boiler furnace is used for cooling the flue gases. Most of the ash is retained as a liquid slag and tapped into the slag tank under the boiler furnace. Thus, the quantity of fly ash contained in the flue gas is low {even so, due to acid rain legislation, they also added scrubbers to the stacks}.
The objective of good cyclone operation is to promote rapid ignition which leads to a self-sustaining combustion process. The point at which this occurs is known as the ignition temperature. Ignition is sustained
-------------------------------------------------- 9 ------------------------------------------------------
-
#BoilerManual #CycloneDescription #Section5 #Page9
The incoming coal particles (except for a few fines that are burned in suspension) are thrown to the walls by centrifugal force, held in the slag layer, then scrubbed by the high velocity secondary air. Thus, the air required to burn the coal is quickly supplied and the products of combustion are rapidly removed. High velocities are required in the cyclone to scrub the surface of the burning coal particles. This scrubbing action quickly removes the ash and supplies air to the surface of the fuel to further combustion.
The release of heat per cu. ft. in the cyclone furnace is very high. However, there is only a small amount of surface in the cyclone and this surface is partially insulated by the covering slag layer. This combination of high heat release and low heat absorption assures the high temperatures necessary to complete combustion and to provide the desired liquid slag covering in the cyclone.
The gaseous products of combustion are discharged through the water-cooled re-entrant throat of the cyclone, into the gas cooling boiler furnace. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away from the burner end and discharges through the slag tap to the boiler furnace. From the furnace, slag is tapped into a slag tank where it is solidified, and disintegrated for disposal. {Disposal at Baldwin consisted of flushing this "bottom ash" to an outside retention pond subjected to evaporation. In the later1980s, this bottom ash plus the precipitated "fly ash" were sold to pavement manufacturing companies to be used in their asphalt and concrete mixes for roadways.}
By this method of combustion, the fuel is burned quickly and completely in the small cyclone chamber, and the boiler furnace is used for cooling the flue gases. Most of the ash is retained as a liquid slag and tapped into the slag tank under the boiler furnace. Thus, the quantity of fly ash contained in the flue gas is low {even so, due to acid rain legislation, they also added scrubbers to the stacks}.
The objective of good cyclone operation is to promote rapid ignition which leads to a self-sustaining combustion process. The point at which this occurs is known as the ignition temperature. Ignition is sustained
-------------------------------------------------- 9 ------------------------------------------------------
-
#BoilerManual #CycloneDescription #Section5 #Page8
burner tangentially and imparts a whirling motion to the incoming coal. Secondary air with a velocity of approximately 300 fps {feet per second} is admitted in the same direction, tangentially, at the roof of the cyclone main barrel and imparts a further whirling or centrifugal action to the coal particles. A small amount of air (up to about 6%) is admitted at the center of the burner. This is known as tertiary air, which is primarily used for cooling the burner front.
The combustibles are burned from the fuel at heat release rates of 450,000 to 800,000 Btu/Cu. ft. per hour and gas temperatures exceeding 3000 Fare developed. these temperatures are sufficiently high to melt the ash into a liquid slag, which forms a layer on the walls of the cyclone.
-------------------------------------------------- 8 ------------------------------------------------------
Alt = Labeled Fig. 6 Cyclone furnace (front view - outside). Very similar to Section 4's Fig. 2 on page 2, but depicts the cyclone frontal view inside of the windbox containment. From top down, then clockwise around the cyclone face are: Windbox enclosure; Crushed coal pipe; Radial burner; Cyclone; Primary-tertiary air duct; Secondary air inlet Secondary air control damper; Lighter. -
#BoilerManual #CycloneDescription #Section5 #Page8
burner tangentially and imparts a whirling motion to the incoming coal. Secondary air with a velocity of approximately 300 fps {feet per second} is admitted in the same direction, tangentially, at the roof of the cyclone main barrel and imparts a further whirling or centrifugal action to the coal particles. A small amount of air (up to about 6%) is admitted at the center of the burner. This is known as tertiary air, which is primarily used for cooling the burner front.
The combustibles are burned from the fuel at heat release rates of 450,000 to 800,000 Btu/Cu. ft. per hour and gas temperatures exceeding 3000 Fare developed. these temperatures are sufficiently high to melt the ash into a liquid slag, which forms a layer on the walls of the cyclone.
-------------------------------------------------- 8 ------------------------------------------------------
Alt = Labeled Fig. 6 Cyclone furnace (front view - outside). Very similar to Section 4's Fig. 2 on page 2, but depicts the cyclone frontal view inside of the windbox containment. From top down, then clockwise around the cyclone face are: Windbox enclosure; Crushed coal pipe; Radial burner; Cyclone; Primary-tertiary air duct; Secondary air inlet Secondary air control damper; Lighter. -
#BoilerManual #CycloneDescription #Section5 #Page8
burner tangentially and imparts a whirling motion to the incoming coal. Secondary air with a velocity of approximately 300 fps {feet per second} is admitted in the same direction, tangentially, at the roof of the cyclone main barrel and imparts a further whirling or centrifugal action to the coal particles. A small amount of air (up to about 6%) is admitted at the center of the burner. This is known as tertiary air, which is primarily used for cooling the burner front.
The combustibles are burned from the fuel at heat release rates of 450,000 to 800,000 Btu/Cu. ft. per hour and gas temperatures exceeding 3000 Fare developed. these temperatures are sufficiently high to melt the ash into a liquid slag, which forms a layer on the walls of the cyclone.
-------------------------------------------------- 8 ------------------------------------------------------
Alt = Labeled Fig. 6 Cyclone furnace (front view - outside). Very similar to Section 4's Fig. 2 on page 2, but depicts the cyclone frontal view inside of the windbox containment. From top down, then clockwise around the cyclone face are: Windbox enclosure; Crushed coal pipe; Radial burner; Cyclone; Primary-tertiary air duct; Secondary air inlet Secondary air control damper; Lighter. -
#BoilerManual #CycloneDescription #Section5 #Page8
burner tangentially and imparts a whirling motion to the incoming coal. Secondary air with a velocity of approximately 300 fps {feet per second} is admitted in the same direction, tangentially, at the roof of the cyclone main barrel and imparts a further whirling or centrifugal action to the coal particles. A small amount of air (up to about 6%) is admitted at the center of the burner. This is known as tertiary air, which is primarily used for cooling the burner front.
The combustibles are burned from the fuel at heat release rates of 450,000 to 800,000 Btu/Cu. ft. per hour and gas temperatures exceeding 3000 Fare developed. these temperatures are sufficiently high to melt the ash into a liquid slag, which forms a layer on the walls of the cyclone.
-------------------------------------------------- 8 ------------------------------------------------------
Alt = Labeled Fig. 6 Cyclone furnace (front view - outside). Very similar to Section 4's Fig. 2 on page 2, but depicts the cyclone frontal view inside of the windbox containment. From top down, then clockwise around the cyclone face are: Windbox enclosure; Crushed coal pipe; Radial burner; Cyclone; Primary-tertiary air duct; Secondary air inlet Secondary air control damper; Lighter. -
#BoilerManual #CycloneDescription #Section5 #Page8
burner tangentially and imparts a whirling motion to the incoming coal. Secondary air with a velocity of approximately 300 fps {feet per second} is admitted in the same direction, tangentially, at the roof of the cyclone main barrel and imparts a further whirling or centrifugal action to the coal particles. A small amount of air (up to about 6%) is admitted at the center of the burner. This is known as tertiary air, which is primarily used for cooling the burner front.
The combustibles are burned from the fuel at heat release rates of 450,000 to 800,000 Btu/Cu. ft. per hour and gas temperatures exceeding 3000 Fare developed. these temperatures are sufficiently high to melt the ash into a liquid slag, which forms a layer on the walls of the cyclone.
-------------------------------------------------- 8 ------------------------------------------------------
Alt = Labeled Fig. 6 Cyclone furnace (front view - outside). Very similar to Section 4's Fig. 2 on page 2, but depicts the cyclone frontal view inside of the windbox containment. From top down, then clockwise around the cyclone face are: Windbox enclosure; Crushed coal pipe; Radial burner; Cyclone; Primary-tertiary air duct; Secondary air inlet Secondary air control damper; Lighter. -
#BoilerManual #CycloneDescription #Section5 #Page7
14. Secondary Air Control Damper (Velocity Damper, Figures 1, 5, & 6) - Located in the secondary air inlet at the top of the cyclone. This damper controls the quantity of secondary air entering the cyclone.
15. Secondary Air Shutoff Damper (Guillotine Damper, Figure 5) - Located in the secondary air inlet before the control damper. This damper will shutoff secondary air flow to an idle cyclone and will control air flow at light-off.
16. Lighter (Figure 6) - Mounted in the face of the cyclone neck circuit adjacent to the secondary air inlet. This retractable oil lighter is designed to ignite the main fuel (coal) and stabilize ignition.
PRINCIPLE OF OPERATION
The cyclone furnace (Figure 1) is a water-cooled horizontal cylinder in which fuel is fired,
heat is released at extremely high rates,and combustion is essentially completed. Its water-cooled tube surfaces are studded and covered with a layer of refractory over most of their area. Crushed coal from a coal crusher is introduced into the burner end of the cyclone. About 17% of the combustion air, termed primary air, enters the
-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Secondary air inlet. The drawing is identical to Section 3's Fig.16 on page 22, but the focus isn't on the Bellmouth and is more simply marked, pointing out the Air flow (left to right), the Secondary air shut-off damper on top left, and the Secondary air control damper, top right. -
#BoilerManual #CycloneDescription #Section5 #Page7
14. Secondary Air Control Damper (Velocity Damper, Figures 1, 5, & 6) - Located in the secondary air inlet at the top of the cyclone. This damper controls the quantity of secondary air entering the cyclone.
15. Secondary Air Shutoff Damper (Guillotine Damper, Figure 5) - Located in the secondary air inlet before the control damper. This damper will shutoff secondary air flow to an idle cyclone and will control air flow at light-off.
16. Lighter (Figure 6) - Mounted in the face of the cyclone neck circuit adjacent to the secondary air inlet. This retractable oil lighter is designed to ignite the main fuel (coal) and stabilize ignition.
PRINCIPLE OF OPERATION
The cyclone furnace (Figure 1) is a water-cooled horizontal cylinder in which fuel is fired,
heat is released at extremely high rates,and combustion is essentially completed. Its water-cooled tube surfaces are studded and covered with a layer of refractory over most of their area. Crushed coal from a coal crusher is introduced into the burner end of the cyclone. About 17% of the combustion air, termed primary air, enters the
-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Secondary air inlet. The drawing is identical to Section 3's Fig.16 on page 22, but the focus isn't on the Bellmouth and is more simply marked, pointing out the Air flow (left to right), the Secondary air shut-off damper on top left, and the Secondary air control damper, top right. -
#BoilerManual #CycloneDescription #Section5 #Page7
14. Secondary Air Control Damper (Velocity Damper, Figures 1, 5, & 6) - Located in the secondary air inlet at the top of the cyclone. This damper controls the quantity of secondary air entering the cyclone.
15. Secondary Air Shutoff Damper (Guillotine Damper, Figure 5) - Located in the secondary air inlet before the control damper. This damper will shutoff secondary air flow to an idle cyclone and will control air flow at light-off.
16. Lighter (Figure 6) - Mounted in the face of the cyclone neck circuit adjacent to the secondary air inlet. This retractable oil lighter is designed to ignite the main fuel (coal) and stabilize ignition.
PRINCIPLE OF OPERATION
The cyclone furnace (Figure 1) is a water-cooled horizontal cylinder in which fuel is fired,
heat is released at extremely high rates,and combustion is essentially completed. Its water-cooled tube surfaces are studded and covered with a layer of refractory over most of their area. Crushed coal from a coal crusher is introduced into the burner end of the cyclone. About 17% of the combustion air, termed primary air, enters the
-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Secondary air inlet. The drawing is identical to Section 3's Fig.16 on page 22, but the focus isn't on the Bellmouth and is more simply marked, pointing out the Air flow (left to right), the Secondary air shut-off damper on top left, and the Secondary air control damper, top right. -
#BoilerManual #CycloneDescription #Section5 #Page7
14. Secondary Air Control Damper (Velocity Damper, Figures 1, 5, & 6) - Located in the secondary air inlet at the top of the cyclone. This damper controls the quantity of secondary air entering the cyclone.
15. Secondary Air Shutoff Damper (Guillotine Damper, Figure 5) - Located in the secondary air inlet before the control damper. This damper will shutoff secondary air flow to an idle cyclone and will control air flow at light-off.
16. Lighter (Figure 6) - Mounted in the face of the cyclone neck circuit adjacent to the secondary air inlet. This retractable oil lighter is designed to ignite the main fuel (coal) and stabilize ignition.
PRINCIPLE OF OPERATION
The cyclone furnace (Figure 1) is a water-cooled horizontal cylinder in which fuel is fired,
heat is released at extremely high rates,and combustion is essentially completed. Its water-cooled tube surfaces are studded and covered with a layer of refractory over most of their area. Crushed coal from a coal crusher is introduced into the burner end of the cyclone. About 17% of the combustion air, termed primary air, enters the
-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Secondary air inlet. The drawing is identical to Section 3's Fig.16 on page 22, but the focus isn't on the Bellmouth and is more simply marked, pointing out the Air flow (left to right), the Secondary air shut-off damper on top left, and the Secondary air control damper, top right. -
#BoilerManual #CycloneDescription #Section5 #Page7
14. Secondary Air Control Damper (Velocity Damper, Figures 1, 5, & 6) - Located in the secondary air inlet at the top of the cyclone. This damper controls the quantity of secondary air entering the cyclone.
15. Secondary Air Shutoff Damper (Guillotine Damper, Figure 5) - Located in the secondary air inlet before the control damper. This damper will shutoff secondary air flow to an idle cyclone and will control air flow at light-off.
16. Lighter (Figure 6) - Mounted in the face of the cyclone neck circuit adjacent to the secondary air inlet. This retractable oil lighter is designed to ignite the main fuel (coal) and stabilize ignition.
PRINCIPLE OF OPERATION
The cyclone furnace (Figure 1) is a water-cooled horizontal cylinder in which fuel is fired,
heat is released at extremely high rates,and combustion is essentially completed. Its water-cooled tube surfaces are studded and covered with a layer of refractory over most of their area. Crushed coal from a coal crusher is introduced into the burner end of the cyclone. About 17% of the combustion air, termed primary air, enters the
-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Secondary air inlet. The drawing is identical to Section 3's Fig.16 on page 22, but the focus isn't on the Bellmouth and is more simply marked, pointing out the Air flow (left to right), the Secondary air shut-off damper on top left, and the Secondary air control damper, top right. -
#BoilerManual #CycloneDescription #Section5 #Page6
from the radial burner end and discharge through the slag tap opening to the boiler furnace. Once on the furnace floor, slag is tapped through the monkeys into the water-cooled slag tank. The slag is solidified and disintegrated for disposal.
* Both the re-entrant throat and slag tap are formed as an integral part of the furnace wall.
13. Secondary Air Inlet (Figures 1, 2, 5, & 6) - 77-84% of the total air to the cyclone is introduced tangentially at the roof of the cyclone main barrel, and in the same direction as the coal and primary air mixture at the radial burner. Secondary air imparts a further whirling or centrifugal action to the coal particles while completing combustion.
-------------------------------------------------- 6 ------------------------------------------------------
Alt = Labeled Fig. 4 Cyclone re-entrant throat tubes (cyclone side). This image is identical to Section 2's Fig. 15 on page 17, labeled Cyclone circuitry -- (re-entrant throat). Its parts are marked identically. It shows a complex drawing of the tubing skeleton of a cyclone with the neck facing forward at an angle. Across the top, lef to right, are pointed out the Re-entrant throat outlet header, Plane of the furnace wall tubes and re-entrant throat outlet header. Surrounding the neck in the middle is pointed out the Re-entrant throat. Across the bottom, left to right, is pointed out the Re-entrant throat inlet header, the Furnace sidewall tubes, the Cyclone inlet header (above which is the Slag tap. Then Re-entrant throat inlet header. -
#BoilerManual #CycloneDescription #Section5 #Page6
from the radial burner end and discharge through the slag tap opening to the boiler furnace. Once on the furnace floor, slag is tapped through the monkeys into the water-cooled slag tank. The slag is solidified and disintegrated for disposal.
* Both the re-entrant throat and slag tap are formed as an integral part of the furnace wall.
13. Secondary Air Inlet (Figures 1, 2, 5, & 6) - 77-84% of the total air to the cyclone is introduced tangentially at the roof of the cyclone main barrel, and in the same direction as the coal and primary air mixture at the radial burner. Secondary air imparts a further whirling or centrifugal action to the coal particles while completing combustion.
-------------------------------------------------- 6 ------------------------------------------------------
Alt = Labeled Fig. 4 Cyclone re-entrant throat tubes (cyclone side). This image is identical to Section 2's Fig. 15 on page 17, labeled Cyclone circuitry -- (re-entrant throat). Its parts are marked identically. It shows a complex drawing of the tubing skeleton of a cyclone with the neck facing forward at an angle. Across the top, lef to right, are pointed out the Re-entrant throat outlet header, Plane of the furnace wall tubes and re-entrant throat outlet header. Surrounding the neck in the middle is pointed out the Re-entrant throat. Across the bottom, left to right, is pointed out the Re-entrant throat inlet header, the Furnace sidewall tubes, the Cyclone inlet header (above which is the Slag tap. Then Re-entrant throat inlet header. -
#BoilerManual #CycloneDescription #Section5 #Page6
from the radial burner end and discharge through the slag tap opening to the boiler furnace. Once on the furnace floor, slag is tapped through the monkeys into the water-cooled slag tank. The slag is solidified and disintegrated for disposal.
* Both the re-entrant throat and slag tap are formed as an integral part of the furnace wall.
13. Secondary Air Inlet (Figures 1, 2, 5, & 6) - 77-84% of the total air to the cyclone is introduced tangentially at the roof of the cyclone main barrel, and in the same direction as the coal and primary air mixture at the radial burner. Secondary air imparts a further whirling or centrifugal action to the coal particles while completing combustion.
-------------------------------------------------- 6 ------------------------------------------------------
Alt = Labeled Fig. 4 Cyclone re-entrant throat tubes (cyclone side). This image is identical to Section 2's Fig. 15 on page 17, labeled Cyclone circuitry -- (re-entrant throat). Its parts are marked identically. It shows a complex drawing of the tubing skeleton of a cyclone with the neck facing forward at an angle. Across the top, lef to right, are pointed out the Re-entrant throat outlet header, Plane of the furnace wall tubes and re-entrant throat outlet header. Surrounding the neck in the middle is pointed out the Re-entrant throat. Across the bottom, left to right, is pointed out the Re-entrant throat inlet header, the Furnace sidewall tubes, the Cyclone inlet header (above which is the Slag tap. Then Re-entrant throat inlet header. -
#BoilerManual #CycloneDescription #Section5 #Page6
from the radial burner end and discharge through the slag tap opening to the boiler furnace. Once on the furnace floor, slag is tapped through the monkeys into the water-cooled slag tank. The slag is solidified and disintegrated for disposal.
* Both the re-entrant throat and slag tap are formed as an integral part of the furnace wall.
13. Secondary Air Inlet (Figures 1, 2, 5, & 6) - 77-84% of the total air to the cyclone is introduced tangentially at the roof of the cyclone main barrel, and in the same direction as the coal and primary air mixture at the radial burner. Secondary air imparts a further whirling or centrifugal action to the coal particles while completing combustion.
-------------------------------------------------- 6 ------------------------------------------------------
Alt = Labeled Fig. 4 Cyclone re-entrant throat tubes (cyclone side). This image is identical to Section 2's Fig. 15 on page 17, labeled Cyclone circuitry -- (re-entrant throat). Its parts are marked identically. It shows a complex drawing of the tubing skeleton of a cyclone with the neck facing forward at an angle. Across the top, lef to right, are pointed out the Re-entrant throat outlet header, Plane of the furnace wall tubes and re-entrant throat outlet header. Surrounding the neck in the middle is pointed out the Re-entrant throat. Across the bottom, left to right, is pointed out the Re-entrant throat inlet header, the Furnace sidewall tubes, the Cyclone inlet header (above which is the Slag tap. Then Re-entrant throat inlet header. -
#BoilerManual #CycloneDescription #Section5 #Page6
from the radial burner end and discharge through the slag tap opening to the boiler furnace. Once on the furnace floor, slag is tapped through the monkeys into the water-cooled slag tank. The slag is solidified and disintegrated for disposal.
* Both the re-entrant throat and slag tap are formed as an integral part of the furnace wall.
13. Secondary Air Inlet (Figures 1, 2, 5, & 6) - 77-84% of the total air to the cyclone is introduced tangentially at the roof of the cyclone main barrel, and in the same direction as the coal and primary air mixture at the radial burner. Secondary air imparts a further whirling or centrifugal action to the coal particles while completing combustion.
-------------------------------------------------- 6 ------------------------------------------------------
Alt = Labeled Fig. 4 Cyclone re-entrant throat tubes (cyclone side). This image is identical to Section 2's Fig. 15 on page 17, labeled Cyclone circuitry -- (re-entrant throat). Its parts are marked identically. It shows a complex drawing of the tubing skeleton of a cyclone with the neck facing forward at an angle. Across the top, lef to right, are pointed out the Re-entrant throat outlet header, Plane of the furnace wall tubes and re-entrant throat outlet header. Surrounding the neck in the middle is pointed out the Re-entrant throat. Across the bottom, left to right, is pointed out the Re-entrant throat inlet header, the Furnace sidewall tubes, the Cyclone inlet header (above which is the Slag tap. Then Re-entrant throat inlet header. -
#BoilerManual #CycloneDescription #Section5 #Page5
baffle plate also serves to keep the coal flow in the burner zone and moving out into the cyclone.
8. Replaceable Wear Blocks (Figure 3) - In the radial burner, the crushed coal is accelerated to the high velocity necessary to throw the heavier particles against the slagged surfaces of the cyclone barrel. This high velocity cases erosion of the burner, which is minimized by the use of tungsten carbide, ceramic, or other erosion-resistant wear liners.
9. Main Barrel (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form a cylinder. Inlet and outlet headers are connected into the boiler circulation systems by means of supply and riser tubes. The barrel tubes are arranged with the use of an intermediate header so that secondary air can be admitted tangentially along part of the cyclone length.
10. Neck (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form the front closure of the main barrel. Inlet and outlet headers are connected into the boiler circulation system by means of supply and riser tubes. The neck tubes are arranged such that the radial burner is positioned in the center of this front neck enclosure. These neck tubes are often referred to as cone tubes.
11. Re-entrant Throat* (Figures 1 & 4) - Closely spaced, water-cooled, studded tubes shaped to form a conical diffuser into the furnace. Inlet and outlet headers are connected to the boiler circulation system by means of supply and riser tubes. The gaseous products of combustion are discharged through the re-entrant throat of the cyclone into the boiler furnace.
12. Slag Tap* (Figures 1 & 4) - Offset water-cooled, studded tubes create an opening through the furnace wall. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away
-------------------------------------------------- 5 ------------------------------------------------------
-
#BoilerManual #CycloneDescription #Section5 #Page5
baffle plate also serves to keep the coal flow in the burner zone and moving out into the cyclone.
8. Replaceable Wear Blocks (Figure 3) - In the radial burner, the crushed coal is accelerated to the high velocity necessary to throw the heavier particles against the slagged surfaces of the cyclone barrel. This high velocity cases erosion of the burner, which is minimized by the use of tungsten carbide, ceramic, or other erosion-resistant wear liners.
9. Main Barrel (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form a cylinder. Inlet and outlet headers are connected into the boiler circulation systems by means of supply and riser tubes. The barrel tubes are arranged with the use of an intermediate header so that secondary air can be admitted tangentially along part of the cyclone length.
10. Neck (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form the front closure of the main barrel. Inlet and outlet headers are connected into the boiler circulation system by means of supply and riser tubes. The neck tubes are arranged such that the radial burner is positioned in the center of this front neck enclosure. These neck tubes are often referred to as cone tubes.
11. Re-entrant Throat* (Figures 1 & 4) - Closely spaced, water-cooled, studded tubes shaped to form a conical diffuser into the furnace. Inlet and outlet headers are connected to the boiler circulation system by means of supply and riser tubes. The gaseous products of combustion are discharged through the re-entrant throat of the cyclone into the boiler furnace.
12. Slag Tap* (Figures 1 & 4) - Offset water-cooled, studded tubes create an opening through the furnace wall. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away
-------------------------------------------------- 5 ------------------------------------------------------
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#BoilerManual #CycloneDescription #Section5 #Page5
baffle plate also serves to keep the coal flow in the burner zone and moving out into the cyclone.
8. Replaceable Wear Blocks (Figure 3) - In the radial burner, the crushed coal is accelerated to the high velocity necessary to throw the heavier particles against the slagged surfaces of the cyclone barrel. This high velocity cases erosion of the burner, which is minimized by the use of tungsten carbide, ceramic, or other erosion-resistant wear liners.
9. Main Barrel (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form a cylinder. Inlet and outlet headers are connected into the boiler circulation systems by means of supply and riser tubes. The barrel tubes are arranged with the use of an intermediate header so that secondary air can be admitted tangentially along part of the cyclone length.
10. Neck (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form the front closure of the main barrel. Inlet and outlet headers are connected into the boiler circulation system by means of supply and riser tubes. The neck tubes are arranged such that the radial burner is positioned in the center of this front neck enclosure. These neck tubes are often referred to as cone tubes.
11. Re-entrant Throat* (Figures 1 & 4) - Closely spaced, water-cooled, studded tubes shaped to form a conical diffuser into the furnace. Inlet and outlet headers are connected to the boiler circulation system by means of supply and riser tubes. The gaseous products of combustion are discharged through the re-entrant throat of the cyclone into the boiler furnace.
12. Slag Tap* (Figures 1 & 4) - Offset water-cooled, studded tubes create an opening through the furnace wall. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away
-------------------------------------------------- 5 ------------------------------------------------------
-
#BoilerManual #CycloneDescription #Section5 #Page5
baffle plate also serves to keep the coal flow in the burner zone and moving out into the cyclone.
8. Replaceable Wear Blocks (Figure 3) - In the radial burner, the crushed coal is accelerated to the high velocity necessary to throw the heavier particles against the slagged surfaces of the cyclone barrel. This high velocity cases erosion of the burner, which is minimized by the use of tungsten carbide, ceramic, or other erosion-resistant wear liners.
9. Main Barrel (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form a cylinder. Inlet and outlet headers are connected into the boiler circulation systems by means of supply and riser tubes. The barrel tubes are arranged with the use of an intermediate header so that secondary air can be admitted tangentially along part of the cyclone length.
10. Neck (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form the front closure of the main barrel. Inlet and outlet headers are connected into the boiler circulation system by means of supply and riser tubes. The neck tubes are arranged such that the radial burner is positioned in the center of this front neck enclosure. These neck tubes are often referred to as cone tubes.
11. Re-entrant Throat* (Figures 1 & 4) - Closely spaced, water-cooled, studded tubes shaped to form a conical diffuser into the furnace. Inlet and outlet headers are connected to the boiler circulation system by means of supply and riser tubes. The gaseous products of combustion are discharged through the re-entrant throat of the cyclone into the boiler furnace.
12. Slag Tap* (Figures 1 & 4) - Offset water-cooled, studded tubes create an opening through the furnace wall. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away
-------------------------------------------------- 5 ------------------------------------------------------
-
#BoilerManual #CycloneDescription #Section5 #Page5
baffle plate also serves to keep the coal flow in the burner zone and moving out into the cyclone.
8. Replaceable Wear Blocks (Figure 3) - In the radial burner, the crushed coal is accelerated to the high velocity necessary to throw the heavier particles against the slagged surfaces of the cyclone barrel. This high velocity cases erosion of the burner, which is minimized by the use of tungsten carbide, ceramic, or other erosion-resistant wear liners.
9. Main Barrel (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form a cylinder. Inlet and outlet headers are connected into the boiler circulation systems by means of supply and riser tubes. The barrel tubes are arranged with the use of an intermediate header so that secondary air can be admitted tangentially along part of the cyclone length.
10. Neck (Figure 1) - Closely spaced, water-cooled, studded tubes shaped to form the front closure of the main barrel. Inlet and outlet headers are connected into the boiler circulation system by means of supply and riser tubes. The neck tubes are arranged such that the radial burner is positioned in the center of this front neck enclosure. These neck tubes are often referred to as cone tubes.
11. Re-entrant Throat* (Figures 1 & 4) - Closely spaced, water-cooled, studded tubes shaped to form a conical diffuser into the furnace. Inlet and outlet headers are connected to the boiler circulation system by means of supply and riser tubes. The gaseous products of combustion are discharged through the re-entrant throat of the cyclone into the boiler furnace.
12. Slag Tap* (Figures 1 & 4) - Offset water-cooled, studded tubes create an opening through the furnace wall. Molten slag in excess of the thin layer retained on the cyclone walls continually drains away
-------------------------------------------------- 5 ------------------------------------------------------
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#BoilerManual #FluidCirculation #Section2 #Page41
9. Spray attemperators inject a fine mist of high purity water to control steam temperature.
10. Gas recirculation is used to control final reheat steam temperatures. There is a spray attemperator in the "hot reheat line", but under normal operating conditions, its use should not be necessary. {I have noted that 33% = 1,400,000 at 2500 psig; Full Load = 4, 200,000 at 3000 psig, econ included. The psig = "pressure per square inch gauge".}
------------------------------------------------- 41 ------------------------------------------------------ -
#BoilerManual #FluidCirculation #Section2 #Page41
9. Spray attemperators inject a fine mist of high purity water to control steam temperature.
10. Gas recirculation is used to control final reheat steam temperatures. There is a spray attemperator in the "hot reheat line", but under normal operating conditions, its use should not be necessary. {I have noted that 33% = 1,400,000 at 2500 psig; Full Load = 4, 200,000 at 3000 psig, econ included. The psig = "pressure per square inch gauge".}
------------------------------------------------- 41 ------------------------------------------------------ -
#BoilerManual #FluidCirculation #Section2 #Page41
9. Spray attemperators inject a fine mist of high purity water to control steam temperature.
10. Gas recirculation is used to control final reheat steam temperatures. There is a spray attemperator in the "hot reheat line", but under normal operating conditions, its use should not be necessary. {I have noted that 33% = 1,400,000 at 2500 psig; Full Load = 4, 200,000 at 3000 psig, econ included. The psig = "pressure per square inch gauge".}
------------------------------------------------- 41 ------------------------------------------------------ -
#BoilerManual #FluidCirculation #Section2 #Page41
9. Spray attemperators inject a fine mist of high purity water to control steam temperature.
10. Gas recirculation is used to control final reheat steam temperatures. There is a spray attemperator in the "hot reheat line", but under normal operating conditions, its use should not be necessary. {I have noted that 33% = 1,400,000 at 2500 psig; Full Load = 4, 200,000 at 3000 psig, econ included. The psig = "pressure per square inch gauge".}
------------------------------------------------- 41 ------------------------------------------------------ -
#BoilerManual #FluidCirculation #Section2 #Page41
9. Spray attemperators inject a fine mist of high purity water to control steam temperature.
10. Gas recirculation is used to control final reheat steam temperatures. There is a spray attemperator in the "hot reheat line", but under normal operating conditions, its use should not be necessary. {I have noted that 33% = 1,400,000 at 2500 psig; Full Load = 4, 200,000 at 3000 psig, econ included. The psig = "pressure per square inch gauge".}
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#BoilerManual #FluidCirculation #Section2 #Page40
Answers for fluid circulation
1. The answer is "B". When you heat water that is converting to steam, the heat produces more steam rather than raising the water temperature.
2. At 3206 psi, water and steam have the same densities. This is known as the critical pressure.
3. The answer to question three is False[/]. The need to match fluid flow and firing rate is [i]criticalat all load levels to avoid overheat conditions.
4. Before a UP boiler is fired, the flow in the furnace circuit must be at least 33% of the full load flow.
5. Internal corrosion can be minimized by controlling the pH of the feedwater and by limiting the amounts of oxygen and carbon dioxide in the feedwater.
6. The first fluid flow path is through the neck of the cyclone. Passes two through six are within the barrel of the cyclone. The seventh pass is through the re-entrant throat.
7. The two purposes are interrelated. First, the mix system keeps fluid temperatures within 80 F of the average temperature of a particular flow path.
8. The connecting tubing from the primary to the secondary superheater crisscrosses to prevent flue gas temperature imbalances from carrying over to the steam.
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#BoilerManual #FluidCirculation #Section2 #Page40
Answers for fluid circulation
1. The answer is "B". When you heat water that is converting to steam, the heat produces more steam rather than raising the water temperature.
2. At 3206 psi, water and steam have the same densities. This is known as the critical pressure.
3. The answer to question three is False[/]. The need to match fluid flow and firing rate is [i]criticalat all load levels to avoid overheat conditions.
4. Before a UP boiler is fired, the flow in the furnace circuit must be at least 33% of the full load flow.
5. Internal corrosion can be minimized by controlling the pH of the feedwater and by limiting the amounts of oxygen and carbon dioxide in the feedwater.
6. The first fluid flow path is through the neck of the cyclone. Passes two through six are within the barrel of the cyclone. The seventh pass is through the re-entrant throat.
7. The two purposes are interrelated. First, the mix system keeps fluid temperatures within 80 F of the average temperature of a particular flow path.
8. The connecting tubing from the primary to the secondary superheater crisscrosses to prevent flue gas temperature imbalances from carrying over to the steam.
------------------------------------------------- 40 ------------------------------------------------------ -
#BoilerManual #FluidCirculation #Section2 #Page40
Answers for fluid circulation
1. The answer is "B". When you heat water that is converting to steam, the heat produces more steam rather than raising the water temperature.
2. At 3206 psi, water and steam have the same densities. This is known as the critical pressure.
3. The answer to question three is False[/]. The need to match fluid flow and firing rate is [i]criticalat all load levels to avoid overheat conditions.
4. Before a UP boiler is fired, the flow in the furnace circuit must be at least 33% of the full load flow.
5. Internal corrosion can be minimized by controlling the pH of the feedwater and by limiting the amounts of oxygen and carbon dioxide in the feedwater.
6. The first fluid flow path is through the neck of the cyclone. Passes two through six are within the barrel of the cyclone. The seventh pass is through the re-entrant throat.
7. The two purposes are interrelated. First, the mix system keeps fluid temperatures within 80 F of the average temperature of a particular flow path.
8. The connecting tubing from the primary to the secondary superheater crisscrosses to prevent flue gas temperature imbalances from carrying over to the steam.
------------------------------------------------- 40 ------------------------------------------------------ -
#BoilerManual #FluidCirculation #Section2 #Page40
Answers for fluid circulation
1. The answer is "B". When you heat water that is converting to steam, the heat produces more steam rather than raising the water temperature.
2. At 3206 psi, water and steam have the same densities. This is known as the critical pressure.
3. The answer to question three is False[/]. The need to match fluid flow and firing rate is [i]criticalat all load levels to avoid overheat conditions.
4. Before a UP boiler is fired, the flow in the furnace circuit must be at least 33% of the full load flow.
5. Internal corrosion can be minimized by controlling the pH of the feedwater and by limiting the amounts of oxygen and carbon dioxide in the feedwater.
6. The first fluid flow path is through the neck of the cyclone. Passes two through six are within the barrel of the cyclone. The seventh pass is through the re-entrant throat.
7. The two purposes are interrelated. First, the mix system keeps fluid temperatures within 80 F of the average temperature of a particular flow path.
8. The connecting tubing from the primary to the secondary superheater crisscrosses to prevent flue gas temperature imbalances from carrying over to the steam.
------------------------------------------------- 40 ------------------------------------------------------ -
#BoilerManual #FluidCirculation #Section2 #Page40
Answers for fluid circulation
1. The answer is "B". When you heat water that is converting to steam, the heat produces more steam rather than raising the water temperature.
2. At 3206 psi, water and steam have the same densities. This is known as the critical pressure.
3. The answer to question three is False[/]. The need to match fluid flow and firing rate is [i]criticalat all load levels to avoid overheat conditions.
4. Before a UP boiler is fired, the flow in the furnace circuit must be at least 33% of the full load flow.
5. Internal corrosion can be minimized by controlling the pH of the feedwater and by limiting the amounts of oxygen and carbon dioxide in the feedwater.
6. The first fluid flow path is through the neck of the cyclone. Passes two through six are within the barrel of the cyclone. The seventh pass is through the re-entrant throat.
7. The two purposes are interrelated. First, the mix system keeps fluid temperatures within 80 F of the average temperature of a particular flow path.
8. The connecting tubing from the primary to the secondary superheater crisscrosses to prevent flue gas temperature imbalances from carrying over to the steam.
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#BoilerManual #FluidCirculation #Section2 #Page39
8. Why is steam flow from the primary superheater outlet crisscrossed on its way to the secondary superheater inlet?
9. What is the function of spray attemperators?
10. How do you control final reheat steam temperature?
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#BoilerManual #FluidCirculation #Section2 #Page39
8. Why is steam flow from the primary superheater outlet crisscrossed on its way to the secondary superheater inlet?
9. What is the function of spray attemperators?
10. How do you control final reheat steam temperature?
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#BoilerManual #FluidCirculation #Section2 #Page39
8. Why is steam flow from the primary superheater outlet crisscrossed on its way to the secondary superheater inlet?
9. What is the function of spray attemperators?
10. How do you control final reheat steam temperature?
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#BoilerManual #FluidCirculation #Section2 #Page39
8. Why is steam flow from the primary superheater outlet crisscrossed on its way to the secondary superheater inlet?
9. What is the function of spray attemperators?
10. How do you control final reheat steam temperature?
------------------------------------------------- 39 ------------------------------------------------------ -
#BoilerManual #FluidCirculation #Section2 #Page39
8. Why is steam flow from the primary superheater outlet crisscrossed on its way to the secondary superheater inlet?
9. What is the function of spray attemperators?
10. How do you control final reheat steam temperature?
------------------------------------------------- 39 ------------------------------------------------------