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#BoilerManual #ProtectingPressureParts #Section10 #Page7

boiler purged. If the boiler is to be kept hot, circulation should be stopped, fans turned off, and all dampers closed.

NOTE: the boiler can be force-cooled if desired, but cooling rates should be limited to 200 F/hr temperature differentials to prevent thermal stress problems. Circulation should continue in the cold cleanup mode. Heat should be rejected through the bypass system to the condenser at a rate determined by the flashtank pressure setpoint. A lower setpoint will result in a higher rejection rate. Air flow can also continue, but care should be taken not to overload the gas recirculation fans (hot gas fans), with cold air.

The combination of air flow and heat rejection from the flashtank should be carefully regulated so that fluid temperature at the convection pass outlet does not change by more than 200 F an hour.

After the boiler has been cooled, it must be properly stored. Wet storage, with all circuits flooded is preferable unless ambient temperatures will drop below freezing. If the boiler needs to be drained, it should be drained and stored under a positive pressure nitrogen cap to keep air out of the tubes to prevent oxygen corrosion.

PROTECTION OF THE REHEATER

Due to the various piping and valving arrangements of the reheater, it is normally impossible to pressurize the reheater with nitrogen. Therefore, the following procedure should be observed. Before shutdown is complete and the reheater is hot enough to produce steam, open the vents or drains on the primary inlet of the reheater. The condenser vacuum will facilitate in the removal of the steam/condensate in the reheater.

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#BoilerManual #ProtectingPressureParts #Section10 #Page7

boiler purged. If the boiler is to be kept hot, circulation should be stopped, fans turned off, and all dampers closed.

NOTE: the boiler can be force-cooled if desired, but cooling rates should be limited to 200 F/hr temperature differentials to prevent thermal stress problems. Circulation should continue in the cold cleanup mode. Heat should be rejected through the bypass system to the condenser at a rate determined by the flashtank pressure setpoint. A lower setpoint will result in a higher rejection rate. Air flow can also continue, but care should be taken not to overload the gas recirculation fans (hot gas fans), with cold air.

The combination of air flow and heat rejection from the flashtank should be carefully regulated so that fluid temperature at the convection pass outlet does not change by more than 200 F an hour.

After the boiler has been cooled, it must be properly stored. Wet storage, with all circuits flooded is preferable unless ambient temperatures will drop below freezing. If the boiler needs to be drained, it should be drained and stored under a positive pressure nitrogen cap to keep air out of the tubes to prevent oxygen corrosion.

PROTECTION OF THE REHEATER

Due to the various piping and valving arrangements of the reheater, it is normally impossible to pressurize the reheater with nitrogen. Therefore, the following procedure should be observed. Before shutdown is complete and the reheater is hot enough to produce steam, open the vents or drains on the primary inlet of the reheater. The condenser vacuum will facilitate in the removal of the steam/condensate in the reheater.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #ProtectingPressureParts #Section10 #Page7

boiler purged. If the boiler is to be kept hot, circulation should be stopped, fans turned off, and all dampers closed.

NOTE: the boiler can be force-cooled if desired, but cooling rates should be limited to 200 F/hr temperature differentials to prevent thermal stress problems. Circulation should continue in the cold cleanup mode. Heat should be rejected through the bypass system to the condenser at a rate determined by the flashtank pressure setpoint. A lower setpoint will result in a higher rejection rate. Air flow can also continue, but care should be taken not to overload the gas recirculation fans (hot gas fans), with cold air.

The combination of air flow and heat rejection from the flashtank should be carefully regulated so that fluid temperature at the convection pass outlet does not change by more than 200 F an hour.

After the boiler has been cooled, it must be properly stored. Wet storage, with all circuits flooded is preferable unless ambient temperatures will drop below freezing. If the boiler needs to be drained, it should be drained and stored under a positive pressure nitrogen cap to keep air out of the tubes to prevent oxygen corrosion.

PROTECTION OF THE REHEATER

Due to the various piping and valving arrangements of the reheater, it is normally impossible to pressurize the reheater with nitrogen. Therefore, the following procedure should be observed. Before shutdown is complete and the reheater is hot enough to produce steam, open the vents or drains on the primary inlet of the reheater. The condenser vacuum will facilitate in the removal of the steam/condensate in the reheater.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #ProtectingPressureParts #Section10 #Page7

boiler purged. If the boiler is to be kept hot, circulation should be stopped, fans turned off, and all dampers closed.

NOTE: the boiler can be force-cooled if desired, but cooling rates should be limited to 200 F/hr temperature differentials to prevent thermal stress problems. Circulation should continue in the cold cleanup mode. Heat should be rejected through the bypass system to the condenser at a rate determined by the flashtank pressure setpoint. A lower setpoint will result in a higher rejection rate. Air flow can also continue, but care should be taken not to overload the gas recirculation fans (hot gas fans), with cold air.

The combination of air flow and heat rejection from the flashtank should be carefully regulated so that fluid temperature at the convection pass outlet does not change by more than 200 F an hour.

After the boiler has been cooled, it must be properly stored. Wet storage, with all circuits flooded is preferable unless ambient temperatures will drop below freezing. If the boiler needs to be drained, it should be drained and stored under a positive pressure nitrogen cap to keep air out of the tubes to prevent oxygen corrosion.

PROTECTION OF THE REHEATER

Due to the various piping and valving arrangements of the reheater, it is normally impossible to pressurize the reheater with nitrogen. Therefore, the following procedure should be observed. Before shutdown is complete and the reheater is hot enough to produce steam, open the vents or drains on the primary inlet of the reheater. The condenser vacuum will facilitate in the removal of the steam/condensate in the reheater.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #ProtectingPressureParts #Section10 #Page7

boiler purged. If the boiler is to be kept hot, circulation should be stopped, fans turned off, and all dampers closed.

NOTE: the boiler can be force-cooled if desired, but cooling rates should be limited to 200 F/hr temperature differentials to prevent thermal stress problems. Circulation should continue in the cold cleanup mode. Heat should be rejected through the bypass system to the condenser at a rate determined by the flashtank pressure setpoint. A lower setpoint will result in a higher rejection rate. Air flow can also continue, but care should be taken not to overload the gas recirculation fans (hot gas fans), with cold air.

The combination of air flow and heat rejection from the flashtank should be carefully regulated so that fluid temperature at the convection pass outlet does not change by more than 200 F an hour.

After the boiler has been cooled, it must be properly stored. Wet storage, with all circuits flooded is preferable unless ambient temperatures will drop below freezing. If the boiler needs to be drained, it should be drained and stored under a positive pressure nitrogen cap to keep air out of the tubes to prevent oxygen corrosion.

PROTECTION OF THE REHEATER

Due to the various piping and valving arrangements of the reheater, it is normally impossible to pressurize the reheater with nitrogen. Therefore, the following procedure should be observed. Before shutdown is complete and the reheater is hot enough to produce steam, open the vents or drains on the primary inlet of the reheater. The condenser vacuum will facilitate in the removal of the steam/condensate in the reheater.

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#BoilerManual #OptimizingCombustion #Section9 #Page7

SLAG TAP FURNACE

Some of the important requirements for adequate slag tap furnace design are:

1. The slag in the furnace must be kept fluid. The furnace temperature must be high and the slag tap furnace should be designed to withstand the maximum temperature reached during combustion, which is usually in excess of 3,000 F.

2. Since fluid slag is heavy as well as extremely hot, it must be securely contained in those regions of the furnace where it tends to collect.

3. The interior surface of the furnace must be chemically inactive to the constituents of the hot slag.

4. A method must be provided to drain slag from the furnace as fast as it is formed, or at least at frequent intervals.

5. Once the molten slag has left the furnace, it must be cooled to a temperature that renders it suitable for ultimate disposal.

To withstand the high temperatures noted above, all the walls and the floor of the furnace are water-cooled. The molten slag continuously drains from the furnace floor into the slag tank. The molten slag disintegrates as it comes in contact with water in the slag tank, and this final slag product is conveyed to disposal.

The difficulty in tapping slag of high fluid temperature is most evident during low load operation. Under these conditions, even a coal with a slag of meedium fluid temperature may not be suitable for slag tapping, since the furnace temperature may not be sufficiently high to attain the degree of fluidity necessary for tapping.

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#BoilerManual #OptimizingCombustion #Section9 #Page7

SLAG TAP FURNACE

Some of the important requirements for adequate slag tap furnace design are:

1. The slag in the furnace must be kept fluid. The furnace temperature must be high and the slag tap furnace should be designed to withstand the maximum temperature reached during combustion, which is usually in excess of 3,000 F.

2. Since fluid slag is heavy as well as extremely hot, it must be securely contained in those regions of the furnace where it tends to collect.

3. The interior surface of the furnace must be chemically inactive to the constituents of the hot slag.

4. A method must be provided to drain slag from the furnace as fast as it is formed, or at least at frequent intervals.

5. Once the molten slag has left the furnace, it must be cooled to a temperature that renders it suitable for ultimate disposal.

To withstand the high temperatures noted above, all the walls and the floor of the furnace are water-cooled. The molten slag continuously drains from the furnace floor into the slag tank. The molten slag disintegrates as it comes in contact with water in the slag tank, and this final slag product is conveyed to disposal.

The difficulty in tapping slag of high fluid temperature is most evident during low load operation. Under these conditions, even a coal with a slag of meedium fluid temperature may not be suitable for slag tapping, since the furnace temperature may not be sufficiently high to attain the degree of fluidity necessary for tapping.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #OptimizingCombustion #Section9 #Page7

SLAG TAP FURNACE

Some of the important requirements for adequate slag tap furnace design are:

1. The slag in the furnace must be kept fluid. The furnace temperature must be high and the slag tap furnace should be designed to withstand the maximum temperature reached during combustion, which is usually in excess of 3,000 F.

2. Since fluid slag is heavy as well as extremely hot, it must be securely contained in those regions of the furnace where it tends to collect.

3. The interior surface of the furnace must be chemically inactive to the constituents of the hot slag.

4. A method must be provided to drain slag from the furnace as fast as it is formed, or at least at frequent intervals.

5. Once the molten slag has left the furnace, it must be cooled to a temperature that renders it suitable for ultimate disposal.

To withstand the high temperatures noted above, all the walls and the floor of the furnace are water-cooled. The molten slag continuously drains from the furnace floor into the slag tank. The molten slag disintegrates as it comes in contact with water in the slag tank, and this final slag product is conveyed to disposal.

The difficulty in tapping slag of high fluid temperature is most evident during low load operation. Under these conditions, even a coal with a slag of meedium fluid temperature may not be suitable for slag tapping, since the furnace temperature may not be sufficiently high to attain the degree of fluidity necessary for tapping.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #OptimizingCombustion #Section9 #Page7

SLAG TAP FURNACE

Some of the important requirements for adequate slag tap furnace design are:

1. The slag in the furnace must be kept fluid. The furnace temperature must be high and the slag tap furnace should be designed to withstand the maximum temperature reached during combustion, which is usually in excess of 3,000 F.

2. Since fluid slag is heavy as well as extremely hot, it must be securely contained in those regions of the furnace where it tends to collect.

3. The interior surface of the furnace must be chemically inactive to the constituents of the hot slag.

4. A method must be provided to drain slag from the furnace as fast as it is formed, or at least at frequent intervals.

5. Once the molten slag has left the furnace, it must be cooled to a temperature that renders it suitable for ultimate disposal.

To withstand the high temperatures noted above, all the walls and the floor of the furnace are water-cooled. The molten slag continuously drains from the furnace floor into the slag tank. The molten slag disintegrates as it comes in contact with water in the slag tank, and this final slag product is conveyed to disposal.

The difficulty in tapping slag of high fluid temperature is most evident during low load operation. Under these conditions, even a coal with a slag of meedium fluid temperature may not be suitable for slag tapping, since the furnace temperature may not be sufficiently high to attain the degree of fluidity necessary for tapping.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #OptimizingCombustion #Section9 #Page7

SLAG TAP FURNACE

Some of the important requirements for adequate slag tap furnace design are:

1. The slag in the furnace must be kept fluid. The furnace temperature must be high and the slag tap furnace should be designed to withstand the maximum temperature reached during combustion, which is usually in excess of 3,000 F.

2. Since fluid slag is heavy as well as extremely hot, it must be securely contained in those regions of the furnace where it tends to collect.

3. The interior surface of the furnace must be chemically inactive to the constituents of the hot slag.

4. A method must be provided to drain slag from the furnace as fast as it is formed, or at least at frequent intervals.

5. Once the molten slag has left the furnace, it must be cooled to a temperature that renders it suitable for ultimate disposal.

To withstand the high temperatures noted above, all the walls and the floor of the furnace are water-cooled. The molten slag continuously drains from the furnace floor into the slag tank. The molten slag disintegrates as it comes in contact with water in the slag tank, and this final slag product is conveyed to disposal.

The difficulty in tapping slag of high fluid temperature is most evident during low load operation. Under these conditions, even a coal with a slag of meedium fluid temperature may not be suitable for slag tapping, since the furnace temperature may not be sufficiently high to attain the degree of fluidity necessary for tapping.

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#BoilerManual #Ramping #Section8 #Page7

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Alt = Labeled Fig. 5 Ramping -- Normal operation at minimum load. Image is just like the others, sideways with the bottom long the right edge and the top along the left edge, with the focus on the superheaters et al but when the system is operating normally with minimum load conditions. Please refer to the main text for details.

#BoilerManual #Ramping #Section8 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Ramping -- Normal operation at minimum load. Image is just like the others, sideways with the bottom long the right edge and the top along the left edge, with the focus on the superheaters et al but when the system is operating normally with minimum load conditions. Please refer to the main text for details.

#BoilerManual #Ramping #Section8 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Ramping -- Normal operation at minimum load. Image is just like the others, sideways with the bottom long the right edge and the top along the left edge, with the focus on the superheaters et al but when the system is operating normally with minimum load conditions. Please refer to the main text for details.

#BoilerManual #Ramping #Section8 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Ramping -- Normal operation at minimum load. Image is just like the others, sideways with the bottom long the right edge and the top along the left edge, with the focus on the superheaters et al but when the system is operating normally with minimum load conditions. Please refer to the main text for details.

#BoilerManual #Ramping #Section8 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 5 Ramping -- Normal operation at minimum load. Image is just like the others, sideways with the bottom long the right edge and the top along the left edge, with the focus on the superheaters et al but when the system is operating normally with minimum load conditions. Please refer to the main text for details.

#BoilerManual #BypassSystem #Section7 #Page7

COLD CLEANUP (Figure 2)

Set controls for cold cleanup mode. The initial circulation for a cold boiler is through the economizer, boiler circuits (furnace and convection pass), primary superheater bypass, flashtank, condenser and condensate polishing system for system cleanup.

During this cold cleanup period, the flow through the boiler should always be equal to or greater than the minimum design flow - 33%. This is accomplished through the primary superheater bypass valves (202). Flow from the convection pass outlet bypasses the PSH through the 202 valves to the flashtank. Valves 200, 201, 205, 207 and 242 are closed.

The low load pressure and flow control portion of the pumping and firing rate controls maintain the pressure within the circuits ahead of the high pressure superheater stop valve, 200. This is accomplished by modulating the PSH bypass valve, 202, and if necessary the SSH bypass valve, 207. The PSH bypass valve, 202, controls the boiler outlet pressure at approximately 700 psi.

The SSH bypass valve, 207, is interlocked closed when the convection pass enclosure outlet temperature is below 300 F. Above 300 F, the 207 automatically opens to control primary superheat outlet temperature.

Full startup flow is pumped through the boiler, PSH bypass, flashtank and on to the condensate polishing system via the condenser for fast system cleanup. During this period every effort should be made to keep oxygen out of the system - seal the turbine and pull a vacuum on the condenser.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #BypassSystem #Section7 #Page7

COLD CLEANUP (Figure 2)

Set controls for cold cleanup mode. The initial circulation for a cold boiler is through the economizer, boiler circuits (furnace and convection pass), primary superheater bypass, flashtank, condenser and condensate polishing system for system cleanup.

During this cold cleanup period, the flow through the boiler should always be equal to or greater than the minimum design flow - 33%. This is accomplished through the primary superheater bypass valves (202). Flow from the convection pass outlet bypasses the PSH through the 202 valves to the flashtank. Valves 200, 201, 205, 207 and 242 are closed.

The low load pressure and flow control portion of the pumping and firing rate controls maintain the pressure within the circuits ahead of the high pressure superheater stop valve, 200. This is accomplished by modulating the PSH bypass valve, 202, and if necessary the SSH bypass valve, 207. The PSH bypass valve, 202, controls the boiler outlet pressure at approximately 700 psi.

The SSH bypass valve, 207, is interlocked closed when the convection pass enclosure outlet temperature is below 300 F. Above 300 F, the 207 automatically opens to control primary superheat outlet temperature.

Full startup flow is pumped through the boiler, PSH bypass, flashtank and on to the condensate polishing system via the condenser for fast system cleanup. During this period every effort should be made to keep oxygen out of the system - seal the turbine and pull a vacuum on the condenser.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #BypassSystem #Section7 #Page7

COLD CLEANUP (Figure 2)

Set controls for cold cleanup mode. The initial circulation for a cold boiler is through the economizer, boiler circuits (furnace and convection pass), primary superheater bypass, flashtank, condenser and condensate polishing system for system cleanup.

During this cold cleanup period, the flow through the boiler should always be equal to or greater than the minimum design flow - 33%. This is accomplished through the primary superheater bypass valves (202). Flow from the convection pass outlet bypasses the PSH through the 202 valves to the flashtank. Valves 200, 201, 205, 207 and 242 are closed.

The low load pressure and flow control portion of the pumping and firing rate controls maintain the pressure within the circuits ahead of the high pressure superheater stop valve, 200. This is accomplished by modulating the PSH bypass valve, 202, and if necessary the SSH bypass valve, 207. The PSH bypass valve, 202, controls the boiler outlet pressure at approximately 700 psi.

The SSH bypass valve, 207, is interlocked closed when the convection pass enclosure outlet temperature is below 300 F. Above 300 F, the 207 automatically opens to control primary superheat outlet temperature.

Full startup flow is pumped through the boiler, PSH bypass, flashtank and on to the condensate polishing system via the condenser for fast system cleanup. During this period every effort should be made to keep oxygen out of the system - seal the turbine and pull a vacuum on the condenser.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #BypassSystem #Section7 #Page7

COLD CLEANUP (Figure 2)

Set controls for cold cleanup mode. The initial circulation for a cold boiler is through the economizer, boiler circuits (furnace and convection pass), primary superheater bypass, flashtank, condenser and condensate polishing system for system cleanup.

During this cold cleanup period, the flow through the boiler should always be equal to or greater than the minimum design flow - 33%. This is accomplished through the primary superheater bypass valves (202). Flow from the convection pass outlet bypasses the PSH through the 202 valves to the flashtank. Valves 200, 201, 205, 207 and 242 are closed.

The low load pressure and flow control portion of the pumping and firing rate controls maintain the pressure within the circuits ahead of the high pressure superheater stop valve, 200. This is accomplished by modulating the PSH bypass valve, 202, and if necessary the SSH bypass valve, 207. The PSH bypass valve, 202, controls the boiler outlet pressure at approximately 700 psi.

The SSH bypass valve, 207, is interlocked closed when the convection pass enclosure outlet temperature is below 300 F. Above 300 F, the 207 automatically opens to control primary superheat outlet temperature.

Full startup flow is pumped through the boiler, PSH bypass, flashtank and on to the condensate polishing system via the condenser for fast system cleanup. During this period every effort should be made to keep oxygen out of the system - seal the turbine and pull a vacuum on the condenser.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #BypassSystem #Section7 #Page7

COLD CLEANUP (Figure 2)

Set controls for cold cleanup mode. The initial circulation for a cold boiler is through the economizer, boiler circuits (furnace and convection pass), primary superheater bypass, flashtank, condenser and condensate polishing system for system cleanup.

During this cold cleanup period, the flow through the boiler should always be equal to or greater than the minimum design flow - 33%. This is accomplished through the primary superheater bypass valves (202). Flow from the convection pass outlet bypasses the PSH through the 202 valves to the flashtank. Valves 200, 201, 205, 207 and 242 are closed.

The low load pressure and flow control portion of the pumping and firing rate controls maintain the pressure within the circuits ahead of the high pressure superheater stop valve, 200. This is accomplished by modulating the PSH bypass valve, 202, and if necessary the SSH bypass valve, 207. The PSH bypass valve, 202, controls the boiler outlet pressure at approximately 700 psi.

The SSH bypass valve, 207, is interlocked closed when the convection pass enclosure outlet temperature is below 300 F. Above 300 F, the 207 automatically opens to control primary superheat outlet temperature.

Full startup flow is pumped through the boiler, PSH bypass, flashtank and on to the condensate polishing system via the condenser for fast system cleanup. During this period every effort should be made to keep oxygen out of the system - seal the turbine and pull a vacuum on the condenser.

-------------------------------------------------- 7 ------------------------------------------------------

#BoilerManual #CycloneOperation #Section6 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 2 Remote common station. Image looks like a column of 6 framed oblong boxes topped by a flattened arch, representing 2 pushbutton switches at the top of the column and the remainder being indicating lights. There are no labels on the lighted oblongs but the top two designated switches are labeled, in top down order, System management ON; System management OFF. They're designated by a diagonal line across the lower right corner of each, and at the bottom of the column it reads "/Slanted line denotes pushbutton"

#BoilerManual #CycloneOperation #Section6 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 2 Remote common station. Image looks like a column of 6 framed oblong boxes topped by a flattened arch, representing 2 pushbutton switches at the top of the column and the remainder being indicating lights. There are no labels on the lighted oblongs but the top two designated switches are labeled, in top down order, System management ON; System management OFF. They're designated by a diagonal line across the lower right corner of each, and at the bottom of the column it reads "/Slanted line denotes pushbutton"

#BoilerManual #CycloneOperation #Section6 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 2 Remote common station. Image looks like a column of 6 framed oblong boxes topped by a flattened arch, representing 2 pushbutton switches at the top of the column and the remainder being indicating lights. There are no labels on the lighted oblongs but the top two designated switches are labeled, in top down order, System management ON; System management OFF. They're designated by a diagonal line across the lower right corner of each, and at the bottom of the column it reads "/Slanted line denotes pushbutton"

#BoilerManual #CycloneOperation #Section6 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 2 Remote common station. Image looks like a column of 6 framed oblong boxes topped by a flattened arch, representing 2 pushbutton switches at the top of the column and the remainder being indicating lights. There are no labels on the lighted oblongs but the top two designated switches are labeled, in top down order, System management ON; System management OFF. They're designated by a diagonal line across the lower right corner of each, and at the bottom of the column it reads "/Slanted line denotes pushbutton"

#BoilerManual #CycloneOperation #Section6 #Page7

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Labeled Fig. 2 Remote common station. Image looks like a column of 6 framed oblong boxes topped by a flattened arch, representing 2 pushbutton switches at the top of the column and the remainder being indicating lights. There are no labels on the lighted oblongs but the top two designated switches are labeled, in top down order, System management ON; System management OFF. They're designated by a diagonal line across the lower right corner of each, and at the bottom of the column it reads "/Slanted line denotes pushbutton"

#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 #Lighters #Section4 #Page7

closes pressure switch 9C to indicate that the lighter is in firing position. Air from the interlock valves also furnish pilot air supply to solenoid valves 8B, 8C and 8D.

{SYMBOL IDENTIFICATION FOR OIL LIGHTER SCHEMATIC images for:

Control valve..................................Manual valve
Air operator....................................Oriface
[sic]Solenoid operator..........................Check valve
Mechanical operator......................Pilot line (air)
Pressure switch}

-------------------------------------------------- 7 ------------------------------------------------------

Alt = Labeled Fig. 3 Lighter control package. It shows an oblong box with a short back panel on which there are 7 switches: 3 on the left and 4 on the right. In left to right order, they're marked Start, Stop, Emergency stop; Oil on, Oil fill, Purge and Cylinder. The oblong box has a cut-away at its bottom showing 2 banks of ports where the outputs of solenoid valves below the box enter. Upper row of ports are labeled, left to right, 9E,9A, 9D, 9C, 9B; lower row of ports are labeled, left to right, 8D, 8C, 8B, 8A.

Below the oblong box is a smaller box marked as having 2 Filters and tubing marked Control air. Superimposed on that filter box are a row of 4 solenoid valves marked 7A, 7B, 7C, and 41, but to the leftmost of that row is indicated a pressure gauge on a module marked Compressed air. Solenoid 7A is further marked as Oil on, with tubing on the bottom labeled Sump. 7B is further labeled Oil fill, with tubing on the bottom labeled Oil in. Solenoids 7C and 41 are paired together with the label, Purge cylinder.

#BoilerManual #Lighters #Section4 #Page7

closes pressure switch 9C to indicate that the lighter is in firing position. Air from the interlock valves also furnish pilot air supply to solenoid valves 8B, 8C and 8D.

{SYMBOL IDENTIFICATION FOR OIL LIGHTER SCHEMATIC images for:

Control valve..................................Manual valve
Air operator....................................Oriface
[sic]Solenoid operator..........................Check valve
Mechanical operator......................Pilot line (air)
Pressure switch}

-------------------------------------------------- 7 ------------------------------------------------------

Alt = Labeled Fig. 3 Lighter control package. It shows an oblong box with a short back panel on which there are 7 switches: 3 on the left and 4 on the right. In left to right order, they're marked Start, Stop, Emergency stop; Oil on, Oil fill, Purge and Cylinder. The oblong box has a cut-away at its bottom showing 2 banks of ports where the outputs of solenoid valves below the box enter. Upper row of ports are labeled, left to right, 9E,9A, 9D, 9C, 9B; lower row of ports are labeled, left to right, 8D, 8C, 8B, 8A.

Below the oblong box is a smaller box marked as having 2 Filters and tubing marked Control air. Superimposed on that filter box are a row of 4 solenoid valves marked 7A, 7B, 7C, and 41, but to the leftmost of that row is indicated a pressure gauge on a module marked Compressed air. Solenoid 7A is further marked as Oil on, with tubing on the bottom labeled Sump. 7B is further labeled Oil fill, with tubing on the bottom labeled Oil in. Solenoids 7C and 41 are paired together with the label, Purge cylinder.

#BoilerManual #Lighters #Section4 #Page7

closes pressure switch 9C to indicate that the lighter is in firing position. Air from the interlock valves also furnish pilot air supply to solenoid valves 8B, 8C and 8D.

{SYMBOL IDENTIFICATION FOR OIL LIGHTER SCHEMATIC images for:

Control valve..................................Manual valve
Air operator....................................Oriface
[sic]Solenoid operator..........................Check valve
Mechanical operator......................Pilot line (air)
Pressure switch}

-------------------------------------------------- 7 ------------------------------------------------------

Alt = Labeled Fig. 3 Lighter control package. It shows an oblong box with a short back panel on which there are 7 switches: 3 on the left and 4 on the right. In left to right order, they're marked Start, Stop, Emergency stop; Oil on, Oil fill, Purge and Cylinder. The oblong box has a cut-away at its bottom showing 2 banks of ports where the outputs of solenoid valves below the box enter. Upper row of ports are labeled, left to right, 9E,9A, 9D, 9C, 9B; lower row of ports are labeled, left to right, 8D, 8C, 8B, 8A.

Below the oblong box is a smaller box marked as having 2 Filters and tubing marked Control air. Superimposed on that filter box are a row of 4 solenoid valves marked 7A, 7B, 7C, and 41, but to the leftmost of that row is indicated a pressure gauge on a module marked Compressed air. Solenoid 7A is further marked as Oil on, with tubing on the bottom labeled Sump. 7B is further labeled Oil fill, with tubing on the bottom labeled Oil in. Solenoids 7C and 41 are paired together with the label, Purge cylinder.

#BoilerManual #Lighters #Section4 #Page7

closes pressure switch 9C to indicate that the lighter is in firing position. Air from the interlock valves also furnish pilot air supply to solenoid valves 8B, 8C and 8D.

{SYMBOL IDENTIFICATION FOR OIL LIGHTER SCHEMATIC images for:

Control valve..................................Manual valve
Air operator....................................Oriface
[sic]Solenoid operator..........................Check valve
Mechanical operator......................Pilot line (air)
Pressure switch}

-------------------------------------------------- 7 ------------------------------------------------------

Alt = Labeled Fig. 3 Lighter control package. It shows an oblong box with a short back panel on which there are 7 switches: 3 on the left and 4 on the right. In left to right order, they're marked Start, Stop, Emergency stop; Oil on, Oil fill, Purge and Cylinder. The oblong box has a cut-away at its bottom showing 2 banks of ports where the outputs of solenoid valves below the box enter. Upper row of ports are labeled, left to right, 9E,9A, 9D, 9C, 9B; lower row of ports are labeled, left to right, 8D, 8C, 8B, 8A.

Below the oblong box is a smaller box marked as having 2 Filters and tubing marked Control air. Superimposed on that filter box are a row of 4 solenoid valves marked 7A, 7B, 7C, and 41, but to the leftmost of that row is indicated a pressure gauge on a module marked Compressed air. Solenoid 7A is further marked as Oil on, with tubing on the bottom labeled Sump. 7B is further labeled Oil fill, with tubing on the bottom labeled Oil in. Solenoids 7C and 41 are paired together with the label, Purge cylinder.

#BoilerManual #Lighters #Section4 #Page7

closes pressure switch 9C to indicate that the lighter is in firing position. Air from the interlock valves also furnish pilot air supply to solenoid valves 8B, 8C and 8D.

{SYMBOL IDENTIFICATION FOR OIL LIGHTER SCHEMATIC images for:

Control valve..................................Manual valve
Air operator....................................Oriface
[sic]Solenoid operator..........................Check valve
Mechanical operator......................Pilot line (air)
Pressure switch}

-------------------------------------------------- 7 ------------------------------------------------------

Alt = Labeled Fig. 3 Lighter control package. It shows an oblong box with a short back panel on which there are 7 switches: 3 on the left and 4 on the right. In left to right order, they're marked Start, Stop, Emergency stop; Oil on, Oil fill, Purge and Cylinder. The oblong box has a cut-away at its bottom showing 2 banks of ports where the outputs of solenoid valves below the box enter. Upper row of ports are labeled, left to right, 9E,9A, 9D, 9C, 9B; lower row of ports are labeled, left to right, 8D, 8C, 8B, 8A.

Below the oblong box is a smaller box marked as having 2 Filters and tubing marked Control air. Superimposed on that filter box are a row of 4 solenoid valves marked 7A, 7B, 7C, and 41, but to the leftmost of that row is indicated a pressure gauge on a module marked Compressed air. Solenoid 7A is further marked as Oil on, with tubing on the bottom labeled Sump. 7B is further labeled Oil fill, with tubing on the bottom labeled Oil in. Solenoids 7C and 41 are paired together with the label, Purge cylinder.

#BoilerManual #AirAndGasFlow #Section3 #Page7

The total amount of combustion air required per cyclone is divided into three flow paths. A small take-off duct directs a portion of the combustion air from the windbox to the burner area of the cyclone

-------------------------------------------------- 7 ------------------------------------------------------
Alt = The top image is labeled Fig. 3 Fan vibration chart. At the top is an additional label of "Fan vibration guide". It is a logarithmic graph along the x axis in terms of 0 RPM, 1000 RPM, and 10,000 RPM. The y axis is in terms of Displacement--mils and is in terms of .01, 10, 1.0, 10 and 100. The lower curve begins at the left at the 7 mil displacement mark at x origin point of 100 PM. The lower curve ends at the .01 displacement mark at a little over the 40,000 RPM mark , and the area of the graph under that curve is labeled Good operation range. The upper curve begins on the left approximately at 25 displacement mils at the 100 RPM origin point on the x axis, and ends on the right at .01 displacement mils at the 60,000 RPM mark. The area between the two curves is marked as Rough operation, and the area above the upper curve is labeled Unacceptable.

Fig. 3 is labeled Combustion (secondary) air flow. It is a block diagram of what's indicated as "Center line cyclones. Leftmost is a box inside a box with the inner one marked Furnace and the outer one marked Windbox. 4 lines are drawn between it and the next slim box to the right marked Tot. air. Two lines are drawn between that box and the next box to the right marked Tubular air heater, and to the rightmost, next, is a column of 3 small boxes each marked F.D fan, and two lines are drawn from the tubular air heater box to the column of fan boxes with the top line connecting with the top FD fan and the bottom line connecting with the bottom FD fan. Another line connects the top FD fan to the middle FD fan which, in turn, is connected to the bottom FD fan.

#BoilerManual #AirAndGasFlow #Section3 #Page7

The total amount of combustion air required per cyclone is divided into three flow paths. A small take-off duct directs a portion of the combustion air from the windbox to the burner area of the cyclone

-------------------------------------------------- 7 ------------------------------------------------------
Alt = The top image is labeled Fig. 3 Fan vibration chart. At the top is an additional label of "Fan vibration guide". It is a logarithmic graph along the x axis in terms of 0 RPM, 1000 RPM, and 10,000 RPM. The y axis is in terms of Displacement--mils and is in terms of .01, 10, 1.0, 10 and 100. The lower curve begins at the left at the 7 mil displacement mark at x origin point of 100 PM. The lower curve ends at the .01 displacement mark at a little over the 40,000 RPM mark , and the area of the graph under that curve is labeled Good operation range. The upper curve begins on the left approximately at 25 displacement mils at the 100 RPM origin point on the x axis, and ends on the right at .01 displacement mils at the 60,000 RPM mark. The area between the two curves is marked as Rough operation, and the area above the upper curve is labeled Unacceptable.

Fig. 3 is labeled Combustion (secondary) air flow. It is a block diagram of what's indicated as "Center line cyclones. Leftmost is a box inside a box with the inner one marked Furnace and the outer one marked Windbox. 4 lines are drawn between it and the next slim box to the right marked Tot. air. Two lines are drawn between that box and the next box to the right marked Tubular air heater, and to the rightmost, next, is a column of 3 small boxes each marked F.D fan, and two lines are drawn from the tubular air heater box to the column of fan boxes with the top line connecting with the top FD fan and the bottom line connecting with the bottom FD fan. Another line connects the top FD fan to the middle FD fan which, in turn, is connected to the bottom FD fan.

#BoilerManual #AirAndGasFlow #Section3 #Page7

The total amount of combustion air required per cyclone is divided into three flow paths. A small take-off duct directs a portion of the combustion air from the windbox to the burner area of the cyclone

-------------------------------------------------- 7 ------------------------------------------------------
Alt = The top image is labeled Fig. 3 Fan vibration chart. At the top is an additional label of "Fan vibration guide". It is a logarithmic graph along the x axis in terms of 0 RPM, 1000 RPM, and 10,000 RPM. The y axis is in terms of Displacement--mils and is in terms of .01, 10, 1.0, 10 and 100. The lower curve begins at the left at the 7 mil displacement mark at x origin point of 100 PM. The lower curve ends at the .01 displacement mark at a little over the 40,000 RPM mark , and the area of the graph under that curve is labeled Good operation range. The upper curve begins on the left approximately at 25 displacement mils at the 100 RPM origin point on the x axis, and ends on the right at .01 displacement mils at the 60,000 RPM mark. The area between the two curves is marked as Rough operation, and the area above the upper curve is labeled Unacceptable.

Fig. 3 is labeled Combustion (secondary) air flow. It is a block diagram of what's indicated as "Center line cyclones. Leftmost is a box inside a box with the inner one marked Furnace and the outer one marked Windbox. 4 lines are drawn between it and the next slim box to the right marked Tot. air. Two lines are drawn between that box and the next box to the right marked Tubular air heater, and to the rightmost, next, is a column of 3 small boxes each marked F.D fan, and two lines are drawn from the tubular air heater box to the column of fan boxes with the top line connecting with the top FD fan and the bottom line connecting with the bottom FD fan. Another line connects the top FD fan to the middle FD fan which, in turn, is connected to the bottom FD fan.

#BoilerManual #AirAndGasFlow #Section3 #Page7

The total amount of combustion air required per cyclone is divided into three flow paths. A small take-off duct directs a portion of the combustion air from the windbox to the burner area of the cyclone

-------------------------------------------------- 7 ------------------------------------------------------
Alt = The top image is labeled Fig. 3 Fan vibration chart. At the top is an additional label of "Fan vibration guide". It is a logarithmic graph along the x axis in terms of 0 RPM, 1000 RPM, and 10,000 RPM. The y axis is in terms of Displacement--mils and is in terms of .01, 10, 1.0, 10 and 100. The lower curve begins at the left at the 7 mil displacement mark at x origin point of 100 PM. The lower curve ends at the .01 displacement mark at a little over the 40,000 RPM mark , and the area of the graph under that curve is labeled Good operation range. The upper curve begins on the left approximately at 25 displacement mils at the 100 RPM origin point on the x axis, and ends on the right at .01 displacement mils at the 60,000 RPM mark. The area between the two curves is marked as Rough operation, and the area above the upper curve is labeled Unacceptable.

Fig. 3 is labeled Combustion (secondary) air flow. It is a block diagram of what's indicated as "Center line cyclones. Leftmost is a box inside a box with the inner one marked Furnace and the outer one marked Windbox. 4 lines are drawn between it and the next slim box to the right marked Tot. air. Two lines are drawn between that box and the next box to the right marked Tubular air heater, and to the rightmost, next, is a column of 3 small boxes each marked F.D fan, and two lines are drawn from the tubular air heater box to the column of fan boxes with the top line connecting with the top FD fan and the bottom line connecting with the bottom FD fan. Another line connects the top FD fan to the middle FD fan which, in turn, is connected to the bottom FD fan.

#BoilerManual #AirAndGasFlow #Section3 #Page7

The total amount of combustion air required per cyclone is divided into three flow paths. A small take-off duct directs a portion of the combustion air from the windbox to the burner area of the cyclone

-------------------------------------------------- 7 ------------------------------------------------------
Alt = The top image is labeled Fig. 3 Fan vibration chart. At the top is an additional label of "Fan vibration guide". It is a logarithmic graph along the x axis in terms of 0 RPM, 1000 RPM, and 10,000 RPM. The y axis is in terms of Displacement--mils and is in terms of .01, 10, 1.0, 10 and 100. The lower curve begins at the left at the 7 mil displacement mark at x origin point of 100 PM. The lower curve ends at the .01 displacement mark at a little over the 40,000 RPM mark , and the area of the graph under that curve is labeled Good operation range. The upper curve begins on the left approximately at 25 displacement mils at the 100 RPM origin point on the x axis, and ends on the right at .01 displacement mils at the 60,000 RPM mark. The area between the two curves is marked as Rough operation, and the area above the upper curve is labeled Unacceptable.

Fig. 3 is labeled Combustion (secondary) air flow. It is a block diagram of what's indicated as "Center line cyclones. Leftmost is a box inside a box with the inner one marked Furnace and the outer one marked Windbox. 4 lines are drawn between it and the next slim box to the right marked Tot. air. Two lines are drawn between that box and the next box to the right marked Tubular air heater, and to the rightmost, next, is a column of 3 small boxes each marked F.D fan, and two lines are drawn from the tubular air heater box to the column of fan boxes with the top line connecting with the top FD fan and the bottom line connecting with the bottom FD fan. Another line connects the top FD fan to the middle FD fan which, in turn, is connected to the bottom FD fan.

#BoilerManual #FluidCirculation #Section2 #Page7
{begging pardon for the colored pencil checkerboard on the graph, folks.}

As more heat is added to the furnace tubes, the density difference will become greater, and more pumping power is available from the natural circulation in effect. Up to a point, circulation will naturally increase with increased heat input, providing more flow within the tubes which keeps the furnace tubes cooled as more steam is generated. However, at the critical pressure (3208 psi) natural circulation breaks down. There is no density differential to provide circulation.

A once-through or Universal Pressure (UP) boiler operates in a significantly different manner. All flow through the unit is created by forced circulation with no drum to separate the steam and return the water to the lower furnace circuits. Operating pressure is established by the boiler feed pumps and is independent of the amount of steam being generated. Flow is forced through a number of boiler passes by the feed pumps which are arranged in series, with the fluid picking up additional heat in each pass.

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Figure 7 labeled Steam generation -- subcritical pressure. The graph is laid out like Fig. 3 with points labeled differently (where the x column is labeled in terms of Temperature in degrees, incrementing every 100 degrees + from 300 to 1200; the y row is labeled in Enthalpy -- Btu/lb incrementing every 200 Btus/lb from 400 to 1600). Points A, B and C are on a straight line labeled 2000 psi; from left to right order are Points B, A and C, where C is the start of the steam curve that goes all the way up to the upper right corner of the graph. Point B is at 0% quality while A is at the 20% quality line, and C is at 100%.

#BoilerManual #FluidCirculation #Section2 #Page7
{begging pardon for the colored pencil checkerboard on the graph, folks.}

As more heat is added to the furnace tubes, the density difference will become greater, and more pumping power is available from the natural circulation in effect. Up to a point, circulation will naturally increase with increased heat input, providing more flow within the tubes which keeps the furnace tubes cooled as more steam is generated. However, at the critical pressure (3208 psi) natural circulation breaks down. There is no density differential to provide circulation.

A once-through or Universal Pressure (UP) boiler operates in a significantly different manner. All flow through the unit is created by forced circulation with no drum to separate the steam and return the water to the lower furnace circuits. Operating pressure is established by the boiler feed pumps and is independent of the amount of steam being generated. Flow is forced through a number of boiler passes by the feed pumps which are arranged in series, with the fluid picking up additional heat in each pass.

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Figure 7 labeled Steam generation -- subcritical pressure. The graph is laid out like Fig. 3 with points labeled differently (where the x column is labeled in terms of Temperature in degrees, incrementing every 100 degrees + from 300 to 1200; the y row is labeled in Enthalpy -- Btu/lb incrementing every 200 Btus/lb from 400 to 1600). Points A, B and C are on a straight line labeled 2000 psi; from left to right order are Points B, A and C, where C is the start of the steam curve that goes all the way up to the upper right corner of the graph. Point B is at 0% quality while A is at the 20% quality line, and C is at 100%.

#BoilerManual #FluidCirculation #Section2 #Page7
{begging pardon for the colored pencil checkerboard on the graph, folks.}

As more heat is added to the furnace tubes, the density difference will become greater, and more pumping power is available from the natural circulation in effect. Up to a point, circulation will naturally increase with increased heat input, providing more flow within the tubes which keeps the furnace tubes cooled as more steam is generated. However, at the critical pressure (3208 psi) natural circulation breaks down. There is no density differential to provide circulation.

A once-through or Universal Pressure (UP) boiler operates in a significantly different manner. All flow through the unit is created by forced circulation with no drum to separate the steam and return the water to the lower furnace circuits. Operating pressure is established by the boiler feed pumps and is independent of the amount of steam being generated. Flow is forced through a number of boiler passes by the feed pumps which are arranged in series, with the fluid picking up additional heat in each pass.

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Figure 7 labeled Steam generation -- subcritical pressure. The graph is laid out like Fig. 3 with points labeled differently (where the x column is labeled in terms of Temperature in degrees, incrementing every 100 degrees + from 300 to 1200; the y row is labeled in Enthalpy -- Btu/lb incrementing every 200 Btus/lb from 400 to 1600). Points A, B and C are on a straight line labeled 2000 psi; from left to right order are Points B, A and C, where C is the start of the steam curve that goes all the way up to the upper right corner of the graph. Point B is at 0% quality while A is at the 20% quality line, and C is at 100%.

#BoilerManual #FluidCirculation #Section2 #Page7
{begging pardon for the colored pencil checkerboard on the graph, folks.}

As more heat is added to the furnace tubes, the density difference will become greater, and more pumping power is available from the natural circulation in effect. Up to a point, circulation will naturally increase with increased heat input, providing more flow within the tubes which keeps the furnace tubes cooled as more steam is generated. However, at the critical pressure (3208 psi) natural circulation breaks down. There is no density differential to provide circulation.

A once-through or Universal Pressure (UP) boiler operates in a significantly different manner. All flow through the unit is created by forced circulation with no drum to separate the steam and return the water to the lower furnace circuits. Operating pressure is established by the boiler feed pumps and is independent of the amount of steam being generated. Flow is forced through a number of boiler passes by the feed pumps which are arranged in series, with the fluid picking up additional heat in each pass.

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Figure 7 labeled Steam generation -- subcritical pressure. The graph is laid out like Fig. 3 with points labeled differently (where the x column is labeled in terms of Temperature in degrees, incrementing every 100 degrees + from 300 to 1200; the y row is labeled in Enthalpy -- Btu/lb incrementing every 200 Btus/lb from 400 to 1600). Points A, B and C are on a straight line labeled 2000 psi; from left to right order are Points B, A and C, where C is the start of the steam curve that goes all the way up to the upper right corner of the graph. Point B is at 0% quality while A is at the 20% quality line, and C is at 100%.

#BoilerManual #FluidCirculation #Section2 #Page7
{begging pardon for the colored pencil checkerboard on the graph, folks.}

As more heat is added to the furnace tubes, the density difference will become greater, and more pumping power is available from the natural circulation in effect. Up to a point, circulation will naturally increase with increased heat input, providing more flow within the tubes which keeps the furnace tubes cooled as more steam is generated. However, at the critical pressure (3208 psi) natural circulation breaks down. There is no density differential to provide circulation.

A once-through or Universal Pressure (UP) boiler operates in a significantly different manner. All flow through the unit is created by forced circulation with no drum to separate the steam and return the water to the lower furnace circuits. Operating pressure is established by the boiler feed pumps and is independent of the amount of steam being generated. Flow is forced through a number of boiler passes by the feed pumps which are arranged in series, with the fluid picking up additional heat in each pass.

-------------------------------------------------- 7 ------------------------------------------------------
Alt = Figure 7 labeled Steam generation -- subcritical pressure. The graph is laid out like Fig. 3 with points labeled differently (where the x column is labeled in terms of Temperature in degrees, incrementing every 100 degrees + from 300 to 1200; the y row is labeled in Enthalpy -- Btu/lb incrementing every 200 Btus/lb from 400 to 1600). Points A, B and C are on a straight line labeled 2000 psi; from left to right order are Points B, A and C, where C is the start of the steam curve that goes all the way up to the upper right corner of the graph. Point B is at 0% quality while A is at the 20% quality line, and C is at 100%.

@Su_G #BoilerManual #UnitDescription #Section1 #Page7 is entirely block diagram, Figure 3 Boiler fluid cycle (water-steam-condensate), and I'm afraid my coloring job caused low contrast on the labels. I erased as much of that as I could, but still not sure it'll be readable. (Yeah--had to rework that image, sorry)

Alt = A block diagram with blocks set out over each edge of the paper with arrows indicating that the flow is circular; in the middle is a simplified circular array of double-sided arrows with the bottom side labeled WATER; left side labeled "WATER/STEAM MIXTURE"; top labeled "STEAM"; right side labeled "CONDENSATE".

The inner right side is parallel to the blocks on the outer right side labeled in top-down order and order of flow direction, "Condensor", Condensate pump", and "Condensate polisher".

The inner bottom side is parallel to the outer bottom set of blocks in order from right to left, in flow order, labeled "LP heaters", "Deaerator", "Boiler feed pumps", and "HP heaters".

The inner left side is parallel to the outer left side blocks but the order of flow is from bottom up. Labeled in flow order are: "Economizer", "Downcomers", "Cyclones", "Mix bottles", "Furnace", "Mix bottles", and "Roof inlet header".

The inner top side is parallel to the outer top row of blocks labeled "Roof tubes", "Convection pass", "PSH", "SSH", "HP turbine", "RH", and "IP & LP turbine". PSH = Primary Super Heater; SSH = Secondary Super Heater; HP = High Pressure; RH = Re Heater; IP = Intermediate Pressure; LP = Low Pressure.

-------------------------------------------------- 7------------------------------------------------------

@Su_G #BoilerManual #UnitDescription #Section1 #Page7 is entirely block diagram, Figure 3 Boiler fluid cycle (water-steam-condensate), and I'm afraid my coloring job caused low contrast on the labels. I erased as much of that as I could, but still not sure it'll be readable. (Yeah--had to rework that image, sorry)

Alt = A block diagram with blocks set out over each edge of the paper with arrows indicating that the flow is circular; in the middle is a simplified circular array of double-sided arrows with the bottom side labeled WATER; left side labeled "WATER/STEAM MIXTURE"; top labeled "STEAM"; right side labeled "CONDENSATE".

The inner right side is parallel to the blocks on the outer right side labeled in top-down order and order of flow direction, "Condensor", Condensate pump", and "Condensate polisher".

The inner bottom side is parallel to the outer bottom set of blocks in order from right to left, in flow order, labeled "LP heaters", "Deaerator", "Boiler feed pumps", and "HP heaters".

The inner left side is parallel to the outer left side blocks but the order of flow is from bottom up. Labeled in flow order are: "Economizer", "Downcomers", "Cyclones", "Mix bottles", "Furnace", "Mix bottles", and "Roof inlet header".

The inner top side is parallel to the outer top row of blocks labeled "Roof tubes", "Convection pass", "PSH", "SSH", "HP turbine", "RH", and "IP & LP turbine". PSH = Primary Super Heater; SSH = Secondary Super Heater; HP = High Pressure; RH = Re Heater; IP = Intermediate Pressure; LP = Low Pressure.

-------------------------------------------------- 7------------------------------------------------------

@Su_G #BoilerManual #UnitDescription #Section1 #Page7 is entirely block diagram, Figure 3 Boiler fluid cycle (water-steam-condensate), and I'm afraid my coloring job caused low contrast on the labels. I erased as much of that as I could, but still not sure it'll be readable. (Yeah--had to rework that image, sorry)

Alt = A block diagram with blocks set out over each edge of the paper with arrows indicating that the flow is circular; in the middle is a simplified circular array of double-sided arrows with the bottom side labeled WATER; left side labeled "WATER/STEAM MIXTURE"; top labeled "STEAM"; right side labeled "CONDENSATE".

The inner right side is parallel to the blocks on the outer right side labeled in top-down order and order of flow direction, "Condensor", Condensate pump", and "Condensate polisher".

The inner bottom side is parallel to the outer bottom set of blocks in order from right to left, in flow order, labeled "LP heaters", "Deaerator", "Boiler feed pumps", and "HP heaters".

The inner left side is parallel to the outer left side blocks but the order of flow is from bottom up. Labeled in flow order are: "Economizer", "Downcomers", "Cyclones", "Mix bottles", "Furnace", "Mix bottles", and "Roof inlet header".

The inner top side is parallel to the outer top row of blocks labeled "Roof tubes", "Convection pass", "PSH", "SSH", "HP turbine", "RH", and "IP & LP turbine". PSH = Primary Super Heater; SSH = Secondary Super Heater; HP = High Pressure; RH = Re Heater; IP = Intermediate Pressure; LP = Low Pressure.

-------------------------------------------------- 7------------------------------------------------------

@Su_G #BoilerManual #UnitDescription #Section1 #Page7 is entirely block diagram, Figure 3 Boiler fluid cycle (water-steam-condensate), and I'm afraid my coloring job caused low contrast on the labels. I erased as much of that as I could, but still not sure it'll be readable. (Yeah--had to rework that image, sorry)

Alt = A block diagram with blocks set out over each edge of the paper with arrows indicating that the flow is circular; in the middle is a simplified circular array of double-sided arrows with the bottom side labeled WATER; left side labeled "WATER/STEAM MIXTURE"; top labeled "STEAM"; right side labeled "CONDENSATE".

The inner right side is parallel to the blocks on the outer right side labeled in top-down order and order of flow direction, "Condensor", Condensate pump", and "Condensate polisher".

The inner bottom side is parallel to the outer bottom set of blocks in order from right to left, in flow order, labeled "LP heaters", "Deaerator", "Boiler feed pumps", and "HP heaters".

The inner left side is parallel to the outer left side blocks but the order of flow is from bottom up. Labeled in flow order are: "Economizer", "Downcomers", "Cyclones", "Mix bottles", "Furnace", "Mix bottles", and "Roof inlet header".

The inner top side is parallel to the outer top row of blocks labeled "Roof tubes", "Convection pass", "PSH", "SSH", "HP turbine", "RH", and "IP & LP turbine". PSH = Primary Super Heater; SSH = Secondary Super Heater; HP = High Pressure; RH = Re Heater; IP = Intermediate Pressure; LP = Low Pressure.

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@Su_G #BoilerManual #UnitDescription #Section1 #Page7 is entirely block diagram, Figure 3 Boiler fluid cycle (water-steam-condensate), and I'm afraid my coloring job caused low contrast on the labels. I erased as much of that as I could, but still not sure it'll be readable. (Yeah--had to rework that image, sorry)

Alt = A block diagram with blocks set out over each edge of the paper with arrows indicating that the flow is circular; in the middle is a simplified circular array of double-sided arrows with the bottom side labeled WATER; left side labeled "WATER/STEAM MIXTURE"; top labeled "STEAM"; right side labeled "CONDENSATE".

The inner right side is parallel to the blocks on the outer right side labeled in top-down order and order of flow direction, "Condensor", Condensate pump", and "Condensate polisher".

The inner bottom side is parallel to the outer bottom set of blocks in order from right to left, in flow order, labeled "LP heaters", "Deaerator", "Boiler feed pumps", and "HP heaters".

The inner left side is parallel to the outer left side blocks but the order of flow is from bottom up. Labeled in flow order are: "Economizer", "Downcomers", "Cyclones", "Mix bottles", "Furnace", "Mix bottles", and "Roof inlet header".

The inner top side is parallel to the outer top row of blocks labeled "Roof tubes", "Convection pass", "PSH", "SSH", "HP turbine", "RH", and "IP & LP turbine". PSH = Primary Super Heater; SSH = Secondary Super Heater; HP = High Pressure; RH = Re Heater; IP = Intermediate Pressure; LP = Low Pressure.

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