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#BoilerManual #OptimizingCombustion #Section9 #Page14

although excess air has no direct effect on deposit strength, the higher gas temperatures caused by increased furnace wall slagging, do affect superheater deposition.

Sintering time, or reaction time, is also a very important factor in determining deposit characteristics. Figure 5 shows that if a deposit is not promptly removed, the strength of the deposit increases many times. Thus, establishing sootblower operating frequency and coverage is also an extremely important facet of the overall problem of ash deposition.

FUEL/AIR MEASUREMENT AND CONTROL

On multi-cyclone installations the feeder drives are calibrated so that uniform fuel flow is delivered for the same master signal. The total air

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Alt = Labeled Fig. 3 Viscosity--temperature relationship. A graph laid out with the x axis in terms of Slag temperature--F incremented every 100 degrees. The y axis is in terms of Viscosity--poise, incremented in logarithmic terms, increment markings as follows: 10, 20, 50, 100, 200, 500, 1000, 2000, 5000 and 10000. There are two curves; the leftmost curve begins on the left just before the intersection of 1000 poise and 2000 degrees, then runs downward to where it stops just after the intersection of 20 poise and 2500 degrees; it's marked Reducing atmosphere.

The rightmost curve starts on the left just past the intersection of 10,000 poise and 2100 degrees, then descends where the curve ends at just under 25 poise where it intersects with roughly 2550 degrees.

#BoilerManual #OptimizingCombustion #Section9 #Page14

although excess air has no direct effect on deposit strength, the higher gas temperatures caused by increased furnace wall slagging, do affect superheater deposition.

Sintering time, or reaction time, is also a very important factor in determining deposit characteristics. Figure 5 shows that if a deposit is not promptly removed, the strength of the deposit increases many times. Thus, establishing sootblower operating frequency and coverage is also an extremely important facet of the overall problem of ash deposition.

FUEL/AIR MEASUREMENT AND CONTROL

On multi-cyclone installations the feeder drives are calibrated so that uniform fuel flow is delivered for the same master signal. The total air

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Alt = Labeled Fig. 3 Viscosity--temperature relationship. A graph laid out with the x axis in terms of Slag temperature--F incremented every 100 degrees. The y axis is in terms of Viscosity--poise, incremented in logarithmic terms, increment markings as follows: 10, 20, 50, 100, 200, 500, 1000, 2000, 5000 and 10000. There are two curves; the leftmost curve begins on the left just before the intersection of 1000 poise and 2000 degrees, then runs downward to where it stops just after the intersection of 20 poise and 2500 degrees; it's marked Reducing atmosphere.

The rightmost curve starts on the left just past the intersection of 10,000 poise and 2100 degrees, then descends where the curve ends at just under 25 poise where it intersects with roughly 2550 degrees.

#BoilerManual #Ramping #Section8 #Page14

The 200 valves begin to open just before D as the 201 reaches 80% open. Since approximately 20% load can be carried by the 201 valve, the 200 valves are pulsed open to provide the additional flow requirements at point E. The pressure ramp is complete with the 200 valves open and the unit at 33% load.

Throttle pressure should not change with the initial opening of the 201 valves. A simple flow exchange takes place. Some of the flow which was initially through the 207 valve to the flashtank will be passed directly from the PSH outlet through the 201 to the turbine. Steam flow from the flashtank through the 205 valve will be reduced by the amount of flow through the 201. MW's will increase slightly, as shown in Figure 6B, to correspond to the manual increase in turbine loading.
the 201's. {sic. This is a stray from I don't know what paragraph--it just sits here in the book, orphaned. I'll take this time to note that as a rule I re-type things as I find them on any given page, but I've made exceptions when I find obvious typos or inconsistencies in punctuation, tab intents and minor grammar issues. Purists should note well that I've also scanned every page of this thing.}

During the actual pressure ramp, both throttle pressure and MW's should increase linearly to normal operating pressure and 33% load at point E. For throttle pressure, this is shown by the dotted line on Figure 6B. Actually, most of the pressure drop across the 200 valves is relieved with their initial opening, and throttle pressure will probably rise to normal levels as shown by the solid line. There may also be a slight increase in MW's above the curve shown to correspond to the increased throttle pressure.

As the 201 valves are opened, flow to the turbine is increased as flow through the boiler is maintained at 33% by the boiler feed pumps. To compensate for the increased flow through the 201's, flow to the flashtank must be reduced. This is accomplished by closing the 207 and 202 valves as shown in Figure 6C.

At the time the SSH pressure ramp is started, the 207 valve opening is programmed off of PSH outlet temperature. With the initial opening of the 201 valves at point B, flow through the PSH will try to increase. An

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#BoilerManual #Ramping #Section8 #Page14

The 200 valves begin to open just before D as the 201 reaches 80% open. Since approximately 20% load can be carried by the 201 valve, the 200 valves are pulsed open to provide the additional flow requirements at point E. The pressure ramp is complete with the 200 valves open and the unit at 33% load.

Throttle pressure should not change with the initial opening of the 201 valves. A simple flow exchange takes place. Some of the flow which was initially through the 207 valve to the flashtank will be passed directly from the PSH outlet through the 201 to the turbine. Steam flow from the flashtank through the 205 valve will be reduced by the amount of flow through the 201. MW's will increase slightly, as shown in Figure 6B, to correspond to the manual increase in turbine loading.
the 201's. {sic. This is a stray from I don't know what paragraph--it just sits here in the book, orphaned. I'll take this time to note that as a rule I re-type things as I find them on any given page, but I've made exceptions when I find obvious typos or inconsistencies in punctuation, tab intents and minor grammar issues. Purists should note well that I've also scanned every page of this thing.}

During the actual pressure ramp, both throttle pressure and MW's should increase linearly to normal operating pressure and 33% load at point E. For throttle pressure, this is shown by the dotted line on Figure 6B. Actually, most of the pressure drop across the 200 valves is relieved with their initial opening, and throttle pressure will probably rise to normal levels as shown by the solid line. There may also be a slight increase in MW's above the curve shown to correspond to the increased throttle pressure.

As the 201 valves are opened, flow to the turbine is increased as flow through the boiler is maintained at 33% by the boiler feed pumps. To compensate for the increased flow through the 201's, flow to the flashtank must be reduced. This is accomplished by closing the 207 and 202 valves as shown in Figure 6C.

At the time the SSH pressure ramp is started, the 207 valve opening is programmed off of PSH outlet temperature. With the initial opening of the 201 valves at point B, flow through the PSH will try to increase. An

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#BoilerManual #BypassSystem #Section7 #Page14

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Alt = Labeled Fig. 4C Startup -- Pressure and temperature control. The image is, like the others in this set, sideways with the bottom long the right edge and the top along the left edge, and identical to the others in this set except in this one, the Primary Superheater (PSH) is more involved as depicted by the heavy lines drawn to it. Again, it's the main text that describes best what is happening here.
to it. Again, it's the main text that describes best what is happening here.

#BoilerManual #BypassSystem #Section7 #Page14

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Alt = Labeled Fig. 4C Startup -- Pressure and temperature control. The image is, like the others in this set, sideways with the bottom long the right edge and the top along the left edge, and identical to the others in this set except in this one, the Primary Superheater (PSH) is more involved as depicted by the heavy lines drawn to it. Again, it's the main text that describes best what is happening here.
to it. Again, it's the main text that describes best what is happening here.

#BoilerManual #CycloneOperation #Section6 #Page14

BOILER AIR FLOW DAMPER CONTROL

One minute after a boiler trip, the secondary air shutoff dampers are commanded to light-off. With all cyclone shutoff dampers and control dampers open (including the flue gas recirculation system), the FD and ID fan inlet vanes are opened, until boiler air flow is 25-30% of full load air flow. The air flow is maintained for not less than 5 minutes, to complete the purge cycle.

Whenever the boiler is not tripped, the system will try to maintain boiler air flow between 25% and 30%.

If total boiler air flow is greater than 30%, the damper control scheme, Sequence 4, will initiate a close signal to the secondary air damper controller beginning with cyclone B6. After a 10 second time delay (T.D.O.) if the total air flow is still greater than 30%, the secondary air damper on cyclone A2 will begin to close. Subsequently a 10 second time delay will initiate a close command to the next cyclone (B2) and the next (A6) and so forth until the air flow goes below 30%. The remaining cyclone damper controls will time out. If

the air flow is below 25%, the same procedure is followed with the only difference being the dampers are opened rather than closed.

If after cycling through all the cyclones a demand signal still exists, whether for more or less air flow, an alarm will be annunciated. If air flow is greater than 30%, the annunciator indicates available dampers closed. If the air flow is less than 25% the annunciator indicates available dampers open. {A word about annunciators--you'd expect those to be in the control room, but they're actually elsewhere and at Baldwin, a company called Sentry made units that had large white, labeled lights to go with the alarms.}

Note: When unit load is above 30%, the alarm available dampers closed will be present.

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#BoilerManual #CycloneOperation #Section6 #Page14

BOILER AIR FLOW DAMPER CONTROL

One minute after a boiler trip, the secondary air shutoff dampers are commanded to light-off. With all cyclone shutoff dampers and control dampers open (including the flue gas recirculation system), the FD and ID fan inlet vanes are opened, until boiler air flow is 25-30% of full load air flow. The air flow is maintained for not less than 5 minutes, to complete the purge cycle.

Whenever the boiler is not tripped, the system will try to maintain boiler air flow between 25% and 30%.

If total boiler air flow is greater than 30%, the damper control scheme, Sequence 4, will initiate a close signal to the secondary air damper controller beginning with cyclone B6. After a 10 second time delay (T.D.O.) if the total air flow is still greater than 30%, the secondary air damper on cyclone A2 will begin to close. Subsequently a 10 second time delay will initiate a close command to the next cyclone (B2) and the next (A6) and so forth until the air flow goes below 30%. The remaining cyclone damper controls will time out. If

the air flow is below 25%, the same procedure is followed with the only difference being the dampers are opened rather than closed.

If after cycling through all the cyclones a demand signal still exists, whether for more or less air flow, an alarm will be annunciated. If air flow is greater than 30%, the annunciator indicates available dampers closed. If the air flow is less than 25% the annunciator indicates available dampers open. {A word about annunciators--you'd expect those to be in the control room, but they're actually elsewhere and at Baldwin, a company called Sentry made units that had large white, labeled lights to go with the alarms.}

Note: When unit load is above 30%, the alarm available dampers closed will be present.

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#BoilerManual #CycloneDescription #Section5 #Page14

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Alt = Labeled Fig. 7 Recommended size distribution ranges of coals burned in the cyclone furnace. This is a complex logarithmic graph that is marked at the top SCREEN OPENING, mm. To the left of this marking is an INTERPOLATION SCALE with divisions marked out as such from 1 to 10. The x axis is labeled SCREEN OPENING INCHES, contradicting the marking on top as being in mm. But the increments have 2 parallel labels, the top one in terms of U.S. STANDARD SIEVE DESIGNATION and the lower one in terms of TYLER SIEVE DESIGNATION. The y axis is labeled on both sides of the x axis as PER CENT PASSING BY WEIGHT, incremented from 1 to 99. There is an insert on the lower right of a chart comparing U.S. standard sieve designation to Absolute minimum % passing by wt., which is subdivided to compare Bituminous to Lignite & subbituminous types of coal thus:

U.S. Standard sieve designation..............................Absolute minimum % by wt.
....................................................................Bituminous.......................Lignite & subbituminous
........................ 4 ............................................ 90 ............................................. 97.5
........................ 8 ............................................ 73 ............................................. 88
...................... 16 ............................................ 52 ............................................. 70
...................... 30 ............................................ 34 ............................................. 50
...................... 50 ............................................ 21 ............................................. 34
.................... 100 ............................................ 12 ............................................. 22
.................... 200 ............................................... 7 ............................................ 13

#BoilerManual #CycloneDescription #Section5 #Page14

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Alt = Labeled Fig. 7 Recommended size distribution ranges of coals burned in the cyclone furnace. This is a complex logarithmic graph that is marked at the top SCREEN OPENING, mm. To the left of this marking is an INTERPOLATION SCALE with divisions marked out as such from 1 to 10. The x axis is labeled SCREEN OPENING INCHES, contradicting the marking on top as being in mm. But the increments have 2 parallel labels, the top one in terms of U.S. STANDARD SIEVE DESIGNATION and the lower one in terms of TYLER SIEVE DESIGNATION. The y axis is labeled on both sides of the x axis as PER CENT PASSING BY WEIGHT, incremented from 1 to 99. There is an insert on the lower right of a chart comparing U.S. standard sieve designation to Absolute minimum % passing by wt., which is subdivided to compare Bituminous to Lignite & subbituminous types of coal thus:

U.S. Standard sieve designation..............................Absolute minimum % by wt.
....................................................................Bituminous.......................Lignite & subbituminous
........................ 4 ............................................ 90 ............................................. 97.5
........................ 8 ............................................ 73 ............................................. 88
...................... 16 ............................................ 52 ............................................. 70
...................... 30 ............................................ 34 ............................................. 50
...................... 50 ............................................ 21 ............................................. 34
.................... 100 ............................................ 12 ............................................. 22
.................... 200 ............................................... 7 ............................................ 13

#BoilerManual #Lighters #Section4 #Page14

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Alt = Labeled Fig. 8 Oil purge. The image is on its side such that the bottom is along the right edge of the page and the top is along its left, and it utilizes the mechanical symbols identified in the printed key on page 7. This image is identical to Fig. 5 except the solenoid conditions show what has occurred for the Oil Purge condition.

#BoilerManual #Lighters #Section4 #Page14

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Alt = Labeled Fig. 8 Oil purge. The image is on its side such that the bottom is along the right edge of the page and the top is along its left, and it utilizes the mechanical symbols identified in the printed key on page 7. This image is identical to Fig. 5 except the solenoid conditions show what has occurred for the Oil Purge condition.

#BoilerManual #AirAndGasFlow #Section3 #Page14

should be calibrated, preferably at normal operating pressure and temperature. The relationship between air flow and pressure differential is a square root curve, which means that the differential varies with the square of the flow.

To illustrate this, consider this example. Looking at Figure 10, we see that at 50% rated air flow, the differential pressure is 1 1/4 inches of water {they used a water-filled manometer for the measurement as depicted in Figure 11--the C&I Dept. did in fact have such a manometer in the shop, with red colored water in it}. At twice this air flow, or 100%, the differential pressure is four times greater at 5 inches of water. Anytime the flow is doubled, the differential pressure will be quadrupled. The inverse of this relationship is also true. If the differential pressure is known the flow can be calculated. If twice the present flow is required across a certain restriction, then the flow must be increased until the differential has quadrupled.

As long as the temperature of the fluid, its pressure and restriction do not change, this relationship olds true. Because the actual nature of the

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Alt = Labeled Fig. 10 Square root curve for air flow. X axis is marked Rated air flow (percent) and is incremented in 10s from 0 to 100 with only the 50% line and the 100% line marked as such. Y axis is marked as Differential pressure (inches of water) incremented 0 to 5 with each line marked sequentially. The curve originates at zero and increases at a low angle until around the 40% mark and increases rapidly to the 100% mark.

#BoilerManual #AirAndGasFlow #Section3 #Page14

should be calibrated, preferably at normal operating pressure and temperature. The relationship between air flow and pressure differential is a square root curve, which means that the differential varies with the square of the flow.

To illustrate this, consider this example. Looking at Figure 10, we see that at 50% rated air flow, the differential pressure is 1 1/4 inches of water {they used a water-filled manometer for the measurement as depicted in Figure 11--the C&I Dept. did in fact have such a manometer in the shop, with red colored water in it}. At twice this air flow, or 100%, the differential pressure is four times greater at 5 inches of water. Anytime the flow is doubled, the differential pressure will be quadrupled. The inverse of this relationship is also true. If the differential pressure is known the flow can be calculated. If twice the present flow is required across a certain restriction, then the flow must be increased until the differential has quadrupled.

As long as the temperature of the fluid, its pressure and restriction do not change, this relationship olds true. Because the actual nature of the

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Alt = Labeled Fig. 10 Square root curve for air flow. X axis is marked Rated air flow (percent) and is incremented in 10s from 0 to 100 with only the 50% line and the 100% line marked as such. Y axis is marked as Differential pressure (inches of water) incremented 0 to 5 with each line marked sequentially. The curve originates at zero and increases at a low angle until around the 40% mark and increases rapidly to the 100% mark.

#BoilerManual #FluidCirculation #Section2 #Page14

Cyclone circulation

The cyclone furnace, in the form of a horizontal cylinder is compeletely water-cooled by connection to the main boiler circulation.

The fluid leaving the economizer outlet header is divided equally into the downcomers, one on each side of the unit (Figure 13). Each downcomer supplies seven cyclones, four on one wall and three on the opposing wall. There are 14 cyclones on the unit with seven (7) on the front wall and seven (7) on the rear wall. The cyclone flow paths are interconnected between the front and rear walls as follows: The lower four cyclones on one wall are connected with the upper three cyclones on the opposing wall.

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Alt = Labeled "Figure 13 Cyclone supply downcomer". Simplified drawing of a boiler furnace with the economizer outlet header pointed out and the line shown between that and where the cyclone location is illustrated, labeled "Cyclone supply downcomer".

#BoilerManual #FluidCirculation #Section2 #Page14

Cyclone circulation

The cyclone furnace, in the form of a horizontal cylinder is compeletely water-cooled by connection to the main boiler circulation.

The fluid leaving the economizer outlet header is divided equally into the downcomers, one on each side of the unit (Figure 13). Each downcomer supplies seven cyclones, four on one wall and three on the opposing wall. There are 14 cyclones on the unit with seven (7) on the front wall and seven (7) on the rear wall. The cyclone flow paths are interconnected between the front and rear walls as follows: The lower four cyclones on one wall are connected with the upper three cyclones on the opposing wall.

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Alt = Labeled "Figure 13 Cyclone supply downcomer". Simplified drawing of a boiler furnace with the economizer outlet header pointed out and the line shown between that and where the cyclone location is illustrated, labeled "Cyclone supply downcomer".

@Su_G #BoilerManual #UnitDescription #Section1 #Page14

UNIT CONSTRUCTION

The boiler may be regarded as having two distinct areas (based upon the type of heat transfer taking place), the furnace and the convection pass. This distinction is graphically illustrated in Figure 5.

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Alt = simplified sketch of the entire furnace which can be imagined to be in the shape of an inverted fish hook with the barb on the right side of the page. The labeled Furnace area is along the shank; the convection pass is the horizontal bit between the shank and the barb. Cyclone locations and unlabeled tube areas near the barb part are indicated but not labeled.

@Su_G #BoilerManual #UnitDescription #Section1 #Page14

UNIT CONSTRUCTION

The boiler may be regarded as having two distinct areas (based upon the type of heat transfer taking place), the furnace and the convection pass. This distinction is graphically illustrated in Figure 5.

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Alt = simplified sketch of the entire furnace which can be imagined to be in the shape of an inverted fish hook with the barb on the right side of the page. The labeled Furnace area is along the shank; the convection pass is the horizontal bit between the shank and the barb. Cyclone locations and unlabeled tube areas near the barb part are indicated but not labeled.