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#BoilerManual #OptimizingCombustion #Section9 #Page22

9. Slag viscosity is a term describing how easily slag will flow at a specific temperature. It is important to cyclone furnaces because the slag must be thick enough to hold coal particles, but it must be fluid enough to run out the furnace when an excess builds up. For the cyclone furnace, we need a coal that has ash which melts and flows at 2600 F maximum.

10. The five conditions which affect coal-ash deposits in your furnace are:

........ 1. ___How much ash is in the coal.

........ 2. ___The make-up of the ash itself.

........ 3. ___Firing method.

........ 4. ___Equipment design.

........ 5. ___Operating conditions of the boiler.

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#BoilerManual #OptimizingCombustion #Section9 #Page22

9. Slag viscosity is a term describing how easily slag will flow at a specific temperature. It is important to cyclone furnaces because the slag must be thick enough to hold coal particles, but it must be fluid enough to run out the furnace when an excess builds up. For the cyclone furnace, we need a coal that has ash which melts and flows at 2600 F maximum.

10. The five conditions which affect coal-ash deposits in your furnace are:

........ 1. ___How much ash is in the coal.

........ 2. ___The make-up of the ash itself.

........ 3. ___Firing method.

........ 4. ___Equipment design.

........ 5. ___Operating conditions of the boiler.

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#BoilerManual #Ramping #Section8 #Page22

Questions for ramping

1. The ramp can be initiated when the unit load is ____% and there is ____ psi steam.

2. What valve controls flow from the flashtank to the turbine?

3. True or False.
With all other conditions met, the secondary superheater ramp may be started immediately after you get 700 F at the primary superheater outlet.

4. Many ramp conditions are automatic. What does the operator set?

5. On what do you base firing rate?

6. The ramp begins after the system has stabilized, the turbine is on _____________ and megawatt demand station is increased to _____________.

7. On this graph, at what point does the pressure ramp begin?

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#BoilerManual #Ramping #Section8 #Page22

Questions for ramping

1. The ramp can be initiated when the unit load is ____% and there is ____ psi steam.

2. What valve controls flow from the flashtank to the turbine?

3. True or False.
With all other conditions met, the secondary superheater ramp may be started immediately after you get 700 F at the primary superheater outlet.

4. Many ramp conditions are automatic. What does the operator set?

5. On what do you base firing rate?

6. The ramp begins after the system has stabilized, the turbine is on _____________ and megawatt demand station is increased to _____________.

7. On this graph, at what point does the pressure ramp begin?

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#BoilerManual #BypassSystem #Section7 #Page22

Answers for bypass system

1. Before universal pressure boilers can be fired, a minimum feedwater flow must be established. This is accomplished by the use of the bypass system.

2. The four modes of boiler operation are:

.......... 1. ___Cold Cleanup_______________

.......... 2. ___Hot Cleanup________________

.......... 3. ___Startup____________________

.......... 4. ___Ramping___________________

3. The cold cleanup mode is used to start water circulating through the system. As the name implies, it also provides a time for water cleanup before firing the boiler. Boiler feedwater should be circulated until cation conductivity is less than one micromho.

4. The cold cleanup mode begins by pumping water through the unit, bringing it up to 33% of full load flow. Valves for the superheaters and turbines should be closed. Water should be directed to the high pressure heaters, the economizer, the furnace tubes, the convection pass, and the flashtank. From the flashtank, the water is sent to the condenser and condensate polisher for water cleanup and back to the feed pump.

5. Hot cleanup is very similar to the cold cleanup phase. A major difference is that in hot cleanup, the unit is fired. This means that steam is being generated. Also in hot cleanup, steam is admitted to the primary superheater. Another difference is that since steam is being produced and sent to the flashtank, the 242 valve was allowed to open. This flashtank steam control valve helps control steam pressure in the flashtank and also provides heat recovery in the high pressure heaters and deaerator.

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#BoilerManual #BypassSystem #Section7 #Page22

Answers for bypass system

1. Before universal pressure boilers can be fired, a minimum feedwater flow must be established. This is accomplished by the use of the bypass system.

2. The four modes of boiler operation are:

.......... 1. ___Cold Cleanup_______________

.......... 2. ___Hot Cleanup________________

.......... 3. ___Startup____________________

.......... 4. ___Ramping___________________

3. The cold cleanup mode is used to start water circulating through the system. As the name implies, it also provides a time for water cleanup before firing the boiler. Boiler feedwater should be circulated until cation conductivity is less than one micromho.

4. The cold cleanup mode begins by pumping water through the unit, bringing it up to 33% of full load flow. Valves for the superheaters and turbines should be closed. Water should be directed to the high pressure heaters, the economizer, the furnace tubes, the convection pass, and the flashtank. From the flashtank, the water is sent to the condenser and condensate polisher for water cleanup and back to the feed pump.

5. Hot cleanup is very similar to the cold cleanup phase. A major difference is that in hot cleanup, the unit is fired. This means that steam is being generated. Also in hot cleanup, steam is admitted to the primary superheater. Another difference is that since steam is being produced and sent to the flashtank, the 242 valve was allowed to open. This flashtank steam control valve helps control steam pressure in the flashtank and also provides heat recovery in the high pressure heaters and deaerator.

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#BoilerManual #CycloneOperation #Section6 #Page22

Answers for cyclone operation

1. The four stages involved in cyclone startup are:

.......... 1. ___Furnace must be purged. ________________

.......... 2. ___The lighter mus be successfully ignited.______

.......... 3. ___Boiler must meet start-up conditions.________

.......... 4. ___Cyclone must be started_________________

2. Air flow is controlled by modulating the secondary air shutoff dampers, one at a time, until 25 to 30% total air flow is established. If air flow is under 25%, the dampers are opened, one at a time, until air flow is between 25 and 30% full load air flow.

3. The five boiler firing permissives necessary for cyclone startup are:

.......... 1. Boiler must be out of the trip mode.

.......... 2. Windbox-to-furnace differential pressure should be within correct limits.

.......... 3. Boiler air flow should be greater than 25% full load air flow.

.......... 4. Lighter oil pressure should be greater than 150 psi.

.......... 5. No cyclones should be in the start or stop sequence.

4. When the lighter start button is pushed the control system will first check to see that all boiler and lighter startup permissives have been met. Next, the lighter assembly is inserted and the spark probe is energized. Then, the oil valve opens, allowing oil to flow through the lighter. The oil is ignited by the energized lighter assembly, producing the flame.

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#BoilerManual #CycloneOperation #Section6 #Page22

Answers for cyclone operation

1. The four stages involved in cyclone startup are:

.......... 1. ___Furnace must be purged. ________________

.......... 2. ___The lighter mus be successfully ignited.______

.......... 3. ___Boiler must meet start-up conditions.________

.......... 4. ___Cyclone must be started_________________

2. Air flow is controlled by modulating the secondary air shutoff dampers, one at a time, until 25 to 30% total air flow is established. If air flow is under 25%, the dampers are opened, one at a time, until air flow is between 25 and 30% full load air flow.

3. The five boiler firing permissives necessary for cyclone startup are:

.......... 1. Boiler must be out of the trip mode.

.......... 2. Windbox-to-furnace differential pressure should be within correct limits.

.......... 3. Boiler air flow should be greater than 25% full load air flow.

.......... 4. Lighter oil pressure should be greater than 150 psi.

.......... 5. No cyclones should be in the start or stop sequence.

4. When the lighter start button is pushed the control system will first check to see that all boiler and lighter startup permissives have been met. Next, the lighter assembly is inserted and the spark probe is energized. Then, the oil valve opens, allowing oil to flow through the lighter. The oil is ignited by the energized lighter assembly, producing the flame.

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#BoilerManual #AirAndGasFlow #Section3 #Page22

for the same pressure differential readings on all cyclones. Figure 17 shows a typical air flow calibration curve.

PRIMARY-TERTIARY AIR FLOW MEASUREMENT

Primary-tertiary air flow is measured much in the same manner. An entrance cone located inside the windbox provides the pressure differential required to calculate air flow (Figure 18). In both cases, a high pressure reading (windbox pressure) and a low pressure reading (duct pressure) are compared and create the necessary pressure differential. Primary-tertiary air flow should be calibrated so that equal primary-tertiary air flows are obtained for the same flow differential readings on all cyclones. Figure 19 shows a typical air flow calibration curve.

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Alt = Labeled Fig.16 Bellmouth for measuring secondary air flow differential. This is a depiction of the secondary air ductwork that would be attached to a cyclone; air flow is designated by two arrows on the left of the duct pointing rightward. Two dampers are in the illustration, the Shut-off damper is marked on the left and next to it on the right is marked Secondary air control damper (velocity damper). Capping the left side of the duct is a dome shape marked as Perforated screen, and the air flow arrows indicate air flowing through it. Attached to the topside of the dome is what appears to be a pocket next to but below where the Shut off damper pivots, and the pocket is marked Low pressure tap (duct pressure). On the opposite side of the dome, at the bottom, is a circular representation with a gap indicated, pointed to with the marking High pressure tap (windbox pressure).

#BoilerManual #AirAndGasFlow #Section3 #Page22

for the same pressure differential readings on all cyclones. Figure 17 shows a typical air flow calibration curve.

PRIMARY-TERTIARY AIR FLOW MEASUREMENT

Primary-tertiary air flow is measured much in the same manner. An entrance cone located inside the windbox provides the pressure differential required to calculate air flow (Figure 18). In both cases, a high pressure reading (windbox pressure) and a low pressure reading (duct pressure) are compared and create the necessary pressure differential. Primary-tertiary air flow should be calibrated so that equal primary-tertiary air flows are obtained for the same flow differential readings on all cyclones. Figure 19 shows a typical air flow calibration curve.

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Alt = Labeled Fig.16 Bellmouth for measuring secondary air flow differential. This is a depiction of the secondary air ductwork that would be attached to a cyclone; air flow is designated by two arrows on the left of the duct pointing rightward. Two dampers are in the illustration, the Shut-off damper is marked on the left and next to it on the right is marked Secondary air control damper (velocity damper). Capping the left side of the duct is a dome shape marked as Perforated screen, and the air flow arrows indicate air flowing through it. Attached to the topside of the dome is what appears to be a pocket next to but below where the Shut off damper pivots, and the pocket is marked Low pressure tap (duct pressure). On the opposite side of the dome, at the bottom, is a circular representation with a gap indicated, pointed to with the marking High pressure tap (windbox pressure).

#BoilerManual #FluidCirculation #Section2 #Page22

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Alt = Figure 18 containing 2 parts where PART 1 depicts Unit 1 on the left side, labeled at the top as UNIT 1 FURNACE WALL CIRCUITRY. Depicted on the right side as labeled at the top is PART 2 showing Unit 2, labeled at the top as UNIT 2 FURNACE WALL CIRCUITRY. Both parts have the Roof inlet header pointed out. Both parts depict circuitry in 3 connected columns each, with each column topped by, respectively in left right order, "S.W. 2nd pass", "F.W. 2nd pass, and "R.W. screen". SW is presumed to mean "side wall"; FW = "front wall" and RW = "rear wall".
Comparing the SW column on both units, the only difference is that Unit 2's 2nd pass section is drawn to look longer than that of Unit 1; the Mix bottle between 2nd pass & 1st pass is labeled. The middle column FW is significantly different where Unit 1 shows, top down, its 2nd pass section, Mix bottle pointed out, then 1st pass section while on Unit 2, the top of the column shows a FW 3rd pass, then labeled Mix bottle, then 2nd pass which diverts to a labeled Mix bottle between it and the RW 2nd pass section in the RW column.
This central Mix bottle then also connects to both the FW and RW 1st pass sections. The two parts resume being identical on the bottom section with the furnace floor pointed out in both cases, and a central Cyclone discharge mix bottle pointed out. Plus I scribbled in the left hand margin.

#BoilerManual #FluidCirculation #Section2 #Page22

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Alt = Figure 18 containing 2 parts where PART 1 depicts Unit 1 on the left side, labeled at the top as UNIT 1 FURNACE WALL CIRCUITRY. Depicted on the right side as labeled at the top is PART 2 showing Unit 2, labeled at the top as UNIT 2 FURNACE WALL CIRCUITRY. Both parts have the Roof inlet header pointed out. Both parts depict circuitry in 3 connected columns each, with each column topped by, respectively in left right order, "S.W. 2nd pass", "F.W. 2nd pass, and "R.W. screen". SW is presumed to mean "side wall"; FW = "front wall" and RW = "rear wall".
Comparing the SW column on both units, the only difference is that Unit 2's 2nd pass section is drawn to look longer than that of Unit 1; the Mix bottle between 2nd pass & 1st pass is labeled. The middle column FW is significantly different where Unit 1 shows, top down, its 2nd pass section, Mix bottle pointed out, then 1st pass section while on Unit 2, the top of the column shows a FW 3rd pass, then labeled Mix bottle, then 2nd pass which diverts to a labeled Mix bottle between it and the RW 2nd pass section in the RW column.
This central Mix bottle then also connects to both the FW and RW 1st pass sections. The two parts resume being identical on the bottom section with the furnace floor pointed out in both cases, and a central Cyclone discharge mix bottle pointed out. Plus I scribbled in the left hand margin.

@Su_G #BoilerManual #UnitDescription #Section1 #Page22

Answers for unit description

1. The five material flow paths in your boiler are

..........1. _____Fuel (coal)________________________

..........2. ____Air______________________________

..........3. ____Flue gas__________________________

..........4. ____Steam____________________________

..........5. _____________________________________

2. Studded tubes provide a surface for refractory and slag to adhere to. This provides a layer of insulation

which reduces heat absorption in the cyclone and maintains high gas temperature to liquify coal ash and

complete combustion.

3. Gas recirculation alters the pattern of heat absorption in the boiler. This allows control of furnace

absorption which will effect {sic} steam temperature.Gas recirculation is of particular importance during

startups when furnace absorption is limited to achieve high steam temperature.

4. Coal enters the cyclone at the radial burner where primary air meets it. Primary air picks up the coal and

forces it into the barrel where it is ignited. In the barrel high velocity secondary air is added to complete

combustion in the cyclone. The ash that remains melts into a liquid slag that collects on the cyclone barrel

tubes. Incoming coal particles become lodged in the slag and are scrubbed by the secondary air to

complete combustion.

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This concludes section 1, Unit Description, of the B&W Boiler Training Manual.
The next section, section 2, is FLUID CIRCULATION, 41 pages long, so a separate thread of posts will be issued for that, and I'll add that its coverage of the nature of water as a liquid and a gas has importance in understanding today's climate crisis insofar as a warming atmosphere is capable of retaining a higher level of moisture without precipitation, and it underscores the importance of atmospheric pressure as well. Those concerned over climate issues would do well to read that part. Simply follow the #BoilerManual hashtag.

@Su_G #BoilerManual #UnitDescription #Section1 #Page22

Answers for unit description

1. The five material flow paths in your boiler are

..........1. _____Fuel (coal)________________________

..........2. ____Air______________________________

..........3. ____Flue gas__________________________

..........4. ____Steam____________________________

..........5. _____________________________________

2. Studded tubes provide a surface for refractory and slag to adhere to. This provides a layer of insulation

which reduces heat absorption in the cyclone and maintains high gas temperature to liquify coal ash and

complete combustion.

3. Gas recirculation alters the pattern of heat absorption in the boiler. This allows control of furnace

absorption which will effect {sic} steam temperature.Gas recirculation is of particular importance during

startups when furnace absorption is limited to achieve high steam temperature.

4. Coal enters the cyclone at the radial burner where primary air meets it. Primary air picks up the coal and

forces it into the barrel where it is ignited. In the barrel high velocity secondary air is added to complete

combustion in the cyclone. The ash that remains melts into a liquid slag that collects on the cyclone barrel

tubes. Incoming coal particles become lodged in the slag and are scrubbed by the secondary air to

complete combustion.

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This concludes section 1, Unit Description, of the B&W Boiler Training Manual.
The next section, section 2, is FLUID CIRCULATION, 41 pages long, so a separate thread of posts will be issued for that, and I'll add that its coverage of the nature of water as a liquid and a gas has importance in understanding today's climate crisis insofar as a warming atmosphere is capable of retaining a higher level of moisture without precipitation, and it underscores the importance of atmospheric pressure as well. Those concerned over climate issues would do well to read that part. Simply follow the #BoilerManual hashtag.