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#BoilerManual #OptimizingCombustion #Section9 #Page17

decreased boiler efficiency as well as the formation of combustible products that can present a hazardous condition in the convection pass and air heaters, as well as in the furnace.

In view of he great number of factors involved in the combustion of any fuel, it is obvious that the specific requirements for the proper combustion of the fuel must be considered a distinct problem. It is possible, however, from the foregoing to draw certain general requirements of proper combustion.

1. The admission of an air supply that will assure sufficient oxygen for complete combustion, (fuel/air ratio).

2. Since complete combustion is not necessarily efficient combustion, it must be secured without permitting the dilution of the products of combustion with excess air, (fuel/air ratio).

3. The air supply should be admitted at the proper time in such a manner tht the oxygen of the air comes into free and thorough contact with the combustible substances of the fuel, (time and turbulence).

4. The gases must be maintained at a temperature equal to or above their ignition point until combustion is complete, (temperature).

In this section of the operator training manual we have reviewed the principles of the combustion process and have examined the inefficiencies which result in combustion losses. Suitability of fuels in relation to cyclone operation as well as the by-products of combustion such as slag and coal ash, were examined along with the effect of operating variables on these deposits.

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#BoilerManual #OptimizingCombustion #Section9 #Page17

decreased boiler efficiency as well as the formation of combustible products that can present a hazardous condition in the convection pass and air heaters, as well as in the furnace.

In view of he great number of factors involved in the combustion of any fuel, it is obvious that the specific requirements for the proper combustion of the fuel must be considered a distinct problem. It is possible, however, from the foregoing to draw certain general requirements of proper combustion.

1. The admission of an air supply that will assure sufficient oxygen for complete combustion, (fuel/air ratio).

2. Since complete combustion is not necessarily efficient combustion, it must be secured without permitting the dilution of the products of combustion with excess air, (fuel/air ratio).

3. The air supply should be admitted at the proper time in such a manner tht the oxygen of the air comes into free and thorough contact with the combustible substances of the fuel, (time and turbulence).

4. The gases must be maintained at a temperature equal to or above their ignition point until combustion is complete, (temperature).

In this section of the operator training manual we have reviewed the principles of the combustion process and have examined the inefficiencies which result in combustion losses. Suitability of fuels in relation to cyclone operation as well as the by-products of combustion such as slag and coal ash, were examined along with the effect of operating variables on these deposits.

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#BoilerManual #Ramping #Section8 #Page17

If for some reason the ramp must be interrupted, the MW demand station can be lowered to match the MW demand thus, stopping the gradual ramped increase in load demand. When the ramp must be stopped, firing rate may have to be manually lowered to near its steady state value, as shown at point X on Figure 7. (Note that for any given steam flow there is only one firing rate which will maintain the correct steam temperature and flow). When the ramp is resumed by raising the MW demand station to 33% of full load firing rate should again be increased.

The curve for the de-ramp is also shown in Figure 7. When de-ramping the unit, firing rate must be below its normal steady state value. Heat stored in the boiler tube metals would tend to make steam temperatures high if the normal steady state firing program was followed.

Plots of several of the more important temperatures are shown in Figure 8. All should be allowed to stabilize at the correct values prior to the initial opening of the 201 at point B. There should be very little change between point B and the initiation of the ramp at point
C.

Gas temperature should increase steadily from point C as firing rate is increased. The thermoprobes will retract when gas temperature reaches approximately 1200 F. At this point firing rate control is based on actual steam temperature. SSH outlet temperature should steadily increase from its initial value to final steam temperature at the end of the ramp.

Both PSH outlet and convection pass outlet temperatures should be relatively constant throughout the ramp and should be used as guides for alteration of the firing rate. Sharp changes in either temperature indicate the need for manual adjustment. Of course, PSH outlet temperature can only be used as an indication of firing rate after the 207 valve is completely closed.

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#BoilerManual #Ramping #Section8 #Page17

If for some reason the ramp must be interrupted, the MW demand station can be lowered to match the MW demand thus, stopping the gradual ramped increase in load demand. When the ramp must be stopped, firing rate may have to be manually lowered to near its steady state value, as shown at point X on Figure 7. (Note that for any given steam flow there is only one firing rate which will maintain the correct steam temperature and flow). When the ramp is resumed by raising the MW demand station to 33% of full load firing rate should again be increased.

The curve for the de-ramp is also shown in Figure 7. When de-ramping the unit, firing rate must be below its normal steady state value. Heat stored in the boiler tube metals would tend to make steam temperatures high if the normal steady state firing program was followed.

Plots of several of the more important temperatures are shown in Figure 8. All should be allowed to stabilize at the correct values prior to the initial opening of the 201 at point B. There should be very little change between point B and the initiation of the ramp at point
C.

Gas temperature should increase steadily from point C as firing rate is increased. The thermoprobes will retract when gas temperature reaches approximately 1200 F. At this point firing rate control is based on actual steam temperature. SSH outlet temperature should steadily increase from its initial value to final steam temperature at the end of the ramp.

Both PSH outlet and convection pass outlet temperatures should be relatively constant throughout the ramp and should be used as guides for alteration of the firing rate. Sharp changes in either temperature indicate the need for manual adjustment. Of course, PSH outlet temperature can only be used as an indication of firing rate after the 207 valve is completely closed.

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#BoilerManual #BypassSystem #Section7 #Page17

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Alt = Labeled Fig. 4F Startup -- Turbine synchronized. Image is sideways, of course, with the bottom long the right edge and the top along the left edge, and resembles the others in this series but at this point the system as a whole is involved, with focus on the turbine. Please see the main text for details.

#BoilerManual #BypassSystem #Section7 #Page17

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Alt = Labeled Fig. 4F Startup -- Turbine synchronized. Image is sideways, of course, with the bottom long the right edge and the top along the left edge, and resembles the others in this series but at this point the system as a whole is involved, with focus on the turbine. Please see the main text for details.

#BoilerManual #CycloneOperation #Section6 #Page17

* Cyclone jacket cooling water on.
* Cyclone and lighter trips reset.

When the lighter is required by the cyclone sequence and all permissives are met, the Lighter Ready indicating light is lit.

CYCLONE START SEQUENCE

With the permissives for the boiler, cyclone and lighters satisfied, the cyclone start may be initiated. Depress the Cyclone Start pushbutton, it will backlight red.

With the initiation of the Cyclone Start pushbutton, the start lighter sequence can begin. When the Lighter Start pushbutton is depressed, the lighter assembly will be inserted and the high energy probe energized by the ignition transformer. After a purge delay, the oil valve is opened. At this point a 5 second lighter flame monitor delay will begin. When the delay times out, the secondary air shutoff damper must be at lightoff or above. Also, the primary/tertiary air damper must be open, the lighter must be inserted, and a lighter flame must be detected. With these conditions satisfied, the lighter is successfully lit.

Once the lighter is successfully lit, the Lighter On indicator will backlight red. When a lighter flame is being detected, the white Lighter Flame indicator is lit. {A note about the flame detectors--the naked eye can be fooled into thinking a lighter is lit when it is not just because the eye is likely blinded by other successfully lit cyclones, so an instrument is used incorporating a vacuum tube type detector manufactured by FyrEye...I hope I remember the spelling correctly.}

Following Lighter Successful the coal feeder may be started if the feeder outlet valve is open. Once the feeder speed exceeds 25%, the secondary air control damper will move to the firing position. The secondary air shutoff damper will be fully open. The primary/tertiary air shutoff damper will be at light off or fully open, depending on the windbox

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#BoilerManual #CycloneOperation #Section6 #Page17

* Cyclone jacket cooling water on.
* Cyclone and lighter trips reset.

When the lighter is required by the cyclone sequence and all permissives are met, the Lighter Ready indicating light is lit.

CYCLONE START SEQUENCE

With the permissives for the boiler, cyclone and lighters satisfied, the cyclone start may be initiated. Depress the Cyclone Start pushbutton, it will backlight red.

With the initiation of the Cyclone Start pushbutton, the start lighter sequence can begin. When the Lighter Start pushbutton is depressed, the lighter assembly will be inserted and the high energy probe energized by the ignition transformer. After a purge delay, the oil valve is opened. At this point a 5 second lighter flame monitor delay will begin. When the delay times out, the secondary air shutoff damper must be at lightoff or above. Also, the primary/tertiary air damper must be open, the lighter must be inserted, and a lighter flame must be detected. With these conditions satisfied, the lighter is successfully lit.

Once the lighter is successfully lit, the Lighter On indicator will backlight red. When a lighter flame is being detected, the white Lighter Flame indicator is lit. {A note about the flame detectors--the naked eye can be fooled into thinking a lighter is lit when it is not just because the eye is likely blinded by other successfully lit cyclones, so an instrument is used incorporating a vacuum tube type detector manufactured by FyrEye...I hope I remember the spelling correctly.}

Following Lighter Successful the coal feeder may be started if the feeder outlet valve is open. Once the feeder speed exceeds 25%, the secondary air control damper will move to the firing position. The secondary air shutoff damper will be fully open. The primary/tertiary air shutoff damper will be at light off or fully open, depending on the windbox

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#BoilerManual #CycloneDescription #Section5 #Page17

No more than four (4) cyclones in Path A and/or no more than four (4) cyclones in Path B can be fired at loads of 33% or less. No upper cyclones can be fired at loads below 33%. {I have a note jotted down that lower = odd; upper = even}

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Alt = Labeled Fig. 8 Cyclone water flow paths. This image is nearly identical to Section 2's Fig. 17 on page 19 of that section; instead of leaving the two arrows pointing rightward from cyclones A6 and A5, here they're marked To cyclone discharge mix bottle; at the bottom, Path A bears the additional marking of From cyclone supply downcomer, but a closer look shows that this marking is intended to apply to the Path A flows into each of the cyclones marked with solid input arrows (cyclones B6, B4, B2, A7, A5, A3 and A1); At the top, Part B bears the additional label as From cyclone supply downcomer, but that this marking is intended to apply to the Path A flows into each of the cyclones marked with dashed input arrows (cyclones B7, B5, B3, B1, A6, A4, and A2). Like Fig. 17, the FURNACE REAR WALL is marked as such at the top and the FURNACE FRONT WALL is marked at the bottom.

#BoilerManual #CycloneDescription #Section5 #Page17

No more than four (4) cyclones in Path A and/or no more than four (4) cyclones in Path B can be fired at loads of 33% or less. No upper cyclones can be fired at loads below 33%. {I have a note jotted down that lower = odd; upper = even}

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Alt = Labeled Fig. 8 Cyclone water flow paths. This image is nearly identical to Section 2's Fig. 17 on page 19 of that section; instead of leaving the two arrows pointing rightward from cyclones A6 and A5, here they're marked To cyclone discharge mix bottle; at the bottom, Path A bears the additional marking of From cyclone supply downcomer, but a closer look shows that this marking is intended to apply to the Path A flows into each of the cyclones marked with solid input arrows (cyclones B6, B4, B2, A7, A5, A3 and A1); At the top, Part B bears the additional label as From cyclone supply downcomer, but that this marking is intended to apply to the Path A flows into each of the cyclones marked with dashed input arrows (cyclones B7, B5, B3, B1, A6, A4, and A2). Like Fig. 17, the FURNACE REAR WALL is marked as such at the top and the FURNACE FRONT WALL is marked at the bottom.

#BoilerManual #Lighters #Section4 #Page17

do not scrape). To prevent the cap from seizing use a high temperature compound on the threads.

4. When an atomizer is removed for cleaning, be sure that thte manual oil valve at the lighter is closed to prevent the possibility of oil being discharged onto the burner platform.

5. Check all gaskets and joints.

6. Check 60 mesh filters in the fuel oil and purge air lines. When the pressure gauge on the control unit indicates less than normal oil or air pressure, the filters should be cleaned or replaced as required.

7. Adjust the flow control valves for the desired lighter travel speed.

8. The adjustable stops on the lighters must be adjusted to open the interlock valves.

9. All pressure switches are normally set to close at 70 psi which is the minimum recommended pressure.

10. The purge timer must be set to allow sufficient time to purge all oil from the oil lines between the control unit and the lighters. The correct time can be determined by observing the lighter flame during the purge period. Most of the oil has been purged when the flame goes out, but purge should be continued about 30 seconds beyond flame-out.

11. The cover on the electrical cabinet should be in place at all times, except for maintenance and adjustments. Otherwise, dust can prevent the electrical contacts from closing properly.

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#BoilerManual #Lighters #Section4 #Page17

do not scrape). To prevent the cap from seizing use a high temperature compound on the threads.

4. When an atomizer is removed for cleaning, be sure that thte manual oil valve at the lighter is closed to prevent the possibility of oil being discharged onto the burner platform.

5. Check all gaskets and joints.

6. Check 60 mesh filters in the fuel oil and purge air lines. When the pressure gauge on the control unit indicates less than normal oil or air pressure, the filters should be cleaned or replaced as required.

7. Adjust the flow control valves for the desired lighter travel speed.

8. The adjustable stops on the lighters must be adjusted to open the interlock valves.

9. All pressure switches are normally set to close at 70 psi which is the minimum recommended pressure.

10. The purge timer must be set to allow sufficient time to purge all oil from the oil lines between the control unit and the lighters. The correct time can be determined by observing the lighter flame during the purge period. Most of the oil has been purged when the flame goes out, but purge should be continued about 30 seconds beyond flame-out.

11. The cover on the electrical cabinet should be in place at all times, except for maintenance and adjustments. Otherwise, dust can prevent the electrical contacts from closing properly.

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#BoilerManual #AirAndGasFlow #Section3 #Page17

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Alt = Labeled DENSITY OF AIR TABLE 2 subtitled [b]Change with Temperature - Pressure Constant at 29.92 in. in Hg --that translates into 29.92 inches of Mercury column. The C & I Department did indeed have such a measuring device in its shop.
The table consists of 8 columns, actually 4 pairs with each pair of columns titled, respectively, Temp. F; Density Lb. per cu. ft.; the first pair lists Temp F from 0 to 90 in increments of 10 with corresponding Density measurements. Second pair similarly lists Temp F from 100 to 190; Third pair similarly lists Temp F from 200 to 450; finally, the fourth pair similarly lists Temp F from 500 to 1000.

#BoilerManual #AirAndGasFlow #Section3 #Page17

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Alt = Labeled DENSITY OF AIR TABLE 2 subtitled [b]Change with Temperature - Pressure Constant at 29.92 in. in Hg --that translates into 29.92 inches of Mercury column. The C & I Department did indeed have such a measuring device in its shop.
The table consists of 8 columns, actually 4 pairs with each pair of columns titled, respectively, Temp. F; Density Lb. per cu. ft.; the first pair lists Temp F from 0 to 90 in increments of 10 with corresponding Density measurements. Second pair similarly lists Temp F from 100 to 190; Third pair similarly lists Temp F from 200 to 450; finally, the fourth pair similarly lists Temp F from 500 to 1000.

#BoilerManual #FluidCirculation #Section2 #Page17

Flow enters each cyclone at the lower neck (inlet) header. From the upper neck (outlet) header, each cyclone supplies a separate circuit of another cyclone, which in turn supplies another. Figure 16 helps to illustrate this point. Notice that the natural progression is for the flow to be directed sequentially from front to rear through the cyclone circuits.

Let's follow an example of this typical flow path by referring to Chart I. Beginning with cyclone B7, feedwater enters the lower neck header, flows through the neck tubes, and discharges into the upper neck header. This competes the first circuit. Flow is directed to the second circuit (first barrel) of an adjacent cyclone B5.

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Alt = Labeled Figure 15 Cyclone circuitry -- (re-entrant throat). A complex drawing of the tubing skeleton of a cyclone with the neck facing forward at an angle. Across the top, lef to right, are pointed out the Re-entrant throat outlet header, Plane of the furnace wall tubes and re-entrant throat outlet header. Surrounding the neck in the middle is pointed out the Re-entrant throat. Across the bottom, left to right, is pointed out the Re-entrant throat inlet header, the Furnace sidewall tubes, the Cycloe inlet header (above which is the Slag tap. Then Re-entrant throat inlet header.

#BoilerManual #FluidCirculation #Section2 #Page17

Flow enters each cyclone at the lower neck (inlet) header. From the upper neck (outlet) header, each cyclone supplies a separate circuit of another cyclone, which in turn supplies another. Figure 16 helps to illustrate this point. Notice that the natural progression is for the flow to be directed sequentially from front to rear through the cyclone circuits.

Let's follow an example of this typical flow path by referring to Chart I. Beginning with cyclone B7, feedwater enters the lower neck header, flows through the neck tubes, and discharges into the upper neck header. This competes the first circuit. Flow is directed to the second circuit (first barrel) of an adjacent cyclone B5.

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Alt = Labeled Figure 15 Cyclone circuitry -- (re-entrant throat). A complex drawing of the tubing skeleton of a cyclone with the neck facing forward at an angle. Across the top, lef to right, are pointed out the Re-entrant throat outlet header, Plane of the furnace wall tubes and re-entrant throat outlet header. Surrounding the neck in the middle is pointed out the Re-entrant throat. Across the bottom, left to right, is pointed out the Re-entrant throat inlet header, the Furnace sidewall tubes, the Cycloe inlet header (above which is the Slag tap. Then Re-entrant throat inlet header.

@Su_G #BoilerManual #UnitDescription #Section1 #Page17

The furnace wall tubes are bent to accommodate the cyclone furnaces, observation ports and access doors, sootblowers, recirculated gas ports, and test connections. The floor tubes are bent to form the slag tap openings to discharge the molten ash into the slag tank beneath.

An integral windbox is attached to the furnace wall, in the burner zone of the unit. The windbox provides air distribution to the cyclone furnaces.

Convection Pass Enclosure

With the exception of the roof tubes, the convection pass enclosure for both the horizontal and pendant sections is constructed of membrane tubes.

The portion of the roof over the furnace is constructed of membrane panels. The remainder of the roof, over the pendant and horizontal convection pass, is made of loose tubes suitably spaced to provide for penetration of superheater and reheater tube legs. The convection pass roof tubes are of flat stud construction (Figure 9) between the areas of tube penetration. These flat studs protect and hold in place the backup refractory at the roof line. Roof tubes, tie bars and seal boxes are arranged to form a structural grid to contain furnace or penthouse pressure. Seals around penetrating tube legs are constructed with a layer of refractory at the roof line. Shop applied seal plates welded to the tube legs are seal welded together during erection to afford a completely metallic enclosure.

As a further protection against leakage of dust laden gases into the penthouse, provision is made to pressurize the enclosure slightly above the furnace pressure.

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@Su_G #BoilerManual #UnitDescription #Section1 #Page17

The furnace wall tubes are bent to accommodate the cyclone furnaces, observation ports and access doors, sootblowers, recirculated gas ports, and test connections. The floor tubes are bent to form the slag tap openings to discharge the molten ash into the slag tank beneath.

An integral windbox is attached to the furnace wall, in the burner zone of the unit. The windbox provides air distribution to the cyclone furnaces.

Convection Pass Enclosure

With the exception of the roof tubes, the convection pass enclosure for both the horizontal and pendant sections is constructed of membrane tubes.

The portion of the roof over the furnace is constructed of membrane panels. The remainder of the roof, over the pendant and horizontal convection pass, is made of loose tubes suitably spaced to provide for penetration of superheater and reheater tube legs. The convection pass roof tubes are of flat stud construction (Figure 9) between the areas of tube penetration. These flat studs protect and hold in place the backup refractory at the roof line. Roof tubes, tie bars and seal boxes are arranged to form a structural grid to contain furnace or penthouse pressure. Seals around penetrating tube legs are constructed with a layer of refractory at the roof line. Shop applied seal plates welded to the tube legs are seal welded together during erection to afford a completely metallic enclosure.

As a further protection against leakage of dust laden gases into the penthouse, provision is made to pressurize the enclosure slightly above the furnace pressure.

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