JPH0755104A - Starting method for hot-banked boiler - Google Patents

Abstract

PURPOSE:To prevent damages which can occur due to thermal stress at the time of starting a hot-banked boiler on connection part between a furnace wall and a heat recovery area, suppress the decrease of main steam pressure at starting and stabilize the flow rate of feed water introduced into the furnace wall. CONSTITUTION:Low temperature fluid C1 which has been held in lower part of a hot-banked furnace wall 1 is extracted downward before a feed water pump 8 is started. High temperature fluid H1 held in upper part of the furnace wall 1 is not immediately sent to a steam separator 12. The high temperature fluid H1 is sent to the steam separator 12 after high temperature fluid H2 which has been held in upper part of an economizer 6 is sent to the lower part of the furnace wall 1. In this way, low temperature fluid C2 flows to a furnace wall outlet A after the high temperature fluids H1, H1 has been sent. The high temperature fluid and the low temperature fluid, therefore, do not repeatedly alternate with each other in passing through the furnace wall outlet A. Fluctuating thermal stress is not applied on the connection part of the furnace wall 1. The boiler is prevented from being cooled by the discharge of the low temperature fluid, that is, the decrease of the main steam pressure is suppressed and the variation of water level HL in a steam separator tank 13 caused by pressure does not occur repeatedly so that the feed water flow rate is stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for starting a hot-banked boiler facility.

[0002]

2. Description of the Related Art An example of a general boiler is shown in FIG. 8, in which 1 is a furnace wall having a fuel burner 2 at the bottom,
3 is a rear transmission part (superheater) connected to the upper rear part of the furnace wall 1, 4 is a reheater accommodated in the rear transmission part 3, 5 is a superheater accommodated in the rear transmission part 3, and 6 is The economizer stored in the rear transmission part 3 is an exhaust gas duct connected to the lower part of the rear transmission part 3.

An outline of the flow of water and steam in such a boiler is shown in FIGS. 9 to 12, in which 8 is a water supply pump, and 9 is water for supplying water from the water supply pump 8 to the economizer 6. Water pipe,
Reference numeral 10 denotes water heated by the economizer 6 for the furnace wall tube 1a of the furnace wall 1.
Connecting pipe for supplying the steam generated in the furnace wall pipe 1a to the steam separator 12, and 13 a separated water discharge pipe for separating the separated water separated by the steam separator 12 Air-water separation tank supplied via
The recirculation water supply pipe for returning the water in 3 to the water supply pipe 9, 16 is a boiler recirculation pump connected to the middle part of the recirculation water supply pipe 15, and 17 is a boiler recirculation water pipe in the middle part of the recirculation water supply pipe 15. A recirculation flow rate control valve 18 connected downstream of the circulation pump 16 is connected to the upstream side of the boiler recirculation pump 16 of the recirculation water supply pipe 15 via a drain pipe 19 and the steam separation tank 13 It is a water level control valve that opens when the water level inside reaches the upper limit. The steam from which the water has been separated by the steam separator 12 is sent to a high-pressure steam turbine (not shown) through the superheater 5, and the steam discharged from the high-pressure steam turbine is reheated by the reheater 4 shown in FIG. It can be reheated and supplied to a low-pressure steam turbine (not shown). The steam discharged from the low-pressure steam turbine is returned to water by a condenser (not shown) and can be circulated to the feed water pump 8. Has become.

In the above-mentioned boiler, during normal operation, the combustion gas generated by the combustion of the fuel injected from the fuel burner 2 in the furnace surrounded by the furnace wall 1 rises in the furnace. While heating the water and steam flowing in the furnace wall tube 1a of the furnace wall 1 and being fed into the rear transfer section 3, in the rear transfer section 3, the steam in the furnace wall tube forming the rear transfer section 3 is heated. And the superheater 5 and the reheater 4 shown in FIG.
The steam flowing inside is superheated to heat the water flowing through the economizer 6, and then discharged to the atmosphere via the exhaust gas duct 7.

On the other hand, the water discharged from the water supply pump 8 is
The water is introduced from the water supply pipe 9 into the economizer 6, and heated in the economizer 6 by the exhaust gas descending the rear transmission part 3, and is supplied to the furnace wall pipe 1a of the furnace wall 1 through the connecting pipe 10. In 1a,
The combustion gas rising in the furnace is heated to generate steam.

The steam generated in the furnace wall tube 1a enters the steam-water separator 12 through the connecting pipe 11, and the steam whose water has been separated by the steam-water separator 12 is superheated by the rear transfer section 3 and the superheater 5. Is introduced into the high-pressure steam turbine, is discharged after being driven with the high-pressure steam turbine, and is supplied to the reheater 4. In the reheater 4, the low-pressure steam turbine is reheated by the exhaust gas flowing down the rear transfer section 3. Is discharged to the water by driving the low-pressure steam turbine, returned to water by the condenser, sucked by the water supply pump 8, discharged, and sent to the economizer 6 again.

The water separated by the steam / water separator 12 flows into the steam / water separation tank 13, and when the water level in the steam / water separation tank 13 is between the upper limit water level and the lower limit water level, the recirculation flow rate control is performed. The valve 17 is opened, and the water in the steam / water separation tank 13 is sent from the recirculation water supply pipe 15 to the water supply pipe 9 by the boiler recirculation pump 16 and merges with the water from the water supply pump 8 to save the coal.
Sent to.

Further, when the water level in the steam / water separation tank 13 exceeds the upper limit water level, the water level control valve 18 opens and the water in the steam / water separation tank 13 is discharged from the drain pipe 19 to the condenser until the water level reaches a predetermined level. Be drained to.

Further, when the boiler is stopped, the fuel burner 2 is extinguished, the feed water pump 8, the boiler recirculation pump 16 are stopped, and the recirculation flow rate control valve 17, the water level control valve 18, etc. are also closed.

When the boiler is stopped after the operation, the boiler holds hot cans (hot banking) with the valves 17 and 18 closed, but a convection phenomenon occurs in the furnace wall tube 1a and the economizer 6. Generated, and as a result, furnace wall tube 1a as shown in FIG.
Upper area X ₁ and steam separator 12 inside steam separator tank 1
The high temperature fluid H ₁ stays in the area _{3 and} the area X ₂ above the economizer 6 is reduced.
Of high temperature fluid (steam) H ₂ equal to or higher than the high temperature fluid H ₁ stays in the area, and low temperature fluid C ₁ stays in the area Y ₁ below the furnace wall tube _{1 a} and stays in the area below the economizer 6. A phenomenon occurs in which the low temperature fluid C ₂ having substantially the same temperature and pressure as the low temperature fluid C ₁ stays in Y ₂ and its rear part.

When the boiler is restarted from the above hot banking state, a restart command is issued.
As a stage before igniting the fuel burner 2, the water supply pump 8 is started and water is started to be supplied from the water supply pipe 9 to the economizer 6. For this reason, the fluid in each device will be extruded in a random manner.

That is, the low temperature fluid C _{2 in the} lower part of the economizer 6 is pushed by the water from the water supply pump 8 and moves to the upper part of the economizer 6, and the high temperature fluid H _{2 in the} upper part of the economizer 6 is the furnace wall tube 1a. The low temperature fluid C _{1 in the} lower part of the furnace wall tube 1a moves to the upper part of the furnace wall tube 1a, and the high temperature fluid H _{1 in the} upper part of the furnace wall tube 1a flows into the lower part.
a Extruded outside to enter the steam separator 12, steam separator 1
The high temperature fluid H _{1 in 2} is sent to the superheater 5 and its downstream side (see FIGS. 9 and 10).

When water is still supplied, the water in the lower part of the economizer 6 moves to the upper part of the economizer 6, and the low temperature fluid C _{2 in the} upper part of the economizer 6 is added.
Flows into the lower part of the furnace wall tube 1a, the high temperature fluid H _{2 in the} lower part of the furnace wall tube 1a moves to the upper part of the furnace wall tube 1a, and the low temperature fluid C _{1 in the} upper part of the furnace wall tube 1a passes through the steam separator 12 It is sent to the separation tank 13 (see FIGS. 10 and 11). At this time, when the water level of the steam separation tank 13 reaches the upper limit, the water level control valve 18 opens and the water containing the low temperature fluid C ₁ in the steam separation tank 13 is discharged to the condenser.

When the water supply from the water supply pump 8 is further continued, the water in the economizer 6 flows into the lower part of the furnace wall pipe 1a, and the low temperature fluid C _{2 in the} lower part of the furnace wall pipe 1a moves to the upper part of the furnace wall pipe 1a. Then
The high temperature fluid H _{2 on the} upper part of the furnace wall tube 1a is sent to the steam separator 12 and the steam separation tank 13 (see FIGS. 11 and 12),
The water level in the steam separation tank 13 decreases.

After that, when the low temperature fluid C ₂ is sent to the steam separator 12 and the steam separator tank 13 (FIG. 12), the water level rises, the water level control valve 18 opens, and the boiler recirculation pump 16 is started. At this time, the water in the steam separation tank 13 is
Part of the water is discharged to the condenser, and the rest is circulated by the boiler recirculation pump 16 to enter the recirculation water supply pipe 15 into the water supply pipe 9 and to the economizer 6 together with the water from the water supply pump 8. Supplied. When the boiler recirculation pump 16 is started, the fuel burner 2 shown in FIG. 8 is ignited and combustion is started.

The situation at the time of restarting the boiler will be explained with a graph. When the water supply pump 8 is started at time t _{0 as} shown in FIG. 13 during hot banking of the boiler, a constant water supply pump flow rate W _BFP. Is maintained and water is supplied.

Further, as shown in FIG. 10, when the low temperature fluid C ₁ starts to flow into the furnace wall tube outlet portion A, the temperature T of the furnace wall tube outlet portion A rapidly drops as shown after time t _{1 in} FIG. Started
As shown in FIG. 16, the pressure P in the steam separator 12 is the time t.
After ₂ , the cold fluid C ₁ starts to drop sharply, and the low temperature fluid C ₁ enters the steam / water separation tank 13 from the steam / water separator 12, so as shown in FIG. 17, after time t ₃ , the water level _HL of the steam / water separation tank 13 is reached. Rapidly rises and the water level control valve 18 opens.

As shown in FIG. 11, when the high temperature fluid H ₂ initially in the economizer 6 reaches the upper part of the furnace wall tube 1a and starts passing through the furnace wall tube outlet portion A, as shown in FIG. The temperature T at the outlet A of the furnace wall tube begins to rise at time t ₅ , reaches a peak at time t ₇ , and then gradually decreases.

When the high temperature fluid H ₂ begins to enter the steam / water separator 12 through the outlet A of the furnace wall tube, the pressure P in the steam / water separator 12 is increased by the high temperature fluid H ₂ after time t _6. , It peaks at time t ₈ and then gradually falls. In this case, the pressure P at time t ₈ becomes lower than the pressure at the time of hot banking, but this is due to the low temperature fluid originally retained in the lower part of the furnace wall tube 1a and the upper part of the furnace wall tube 1a and the separation of steam and water. This is because the container 12 has been cooled.

[0020] cryogen C ₂ begins to be transmitted from Rokabekan 1a, low temperature fluid C ₂ flows into the gas-water separator tank 13 via a steam separator 12, Therefore, steam-water separator tank 13
The inner water level H _L gradually increases, and reaches an upper limit at time t _{9 as} shown in FIG. And Thus, the gas-water separator tank 1 at time t ₉
When the water level H _{L in} 3 reaches the upper limit, the boiler recirculation pump 1
6 is started and a constant recirculation pump flow rate W _BRP is maintained as shown in FIG. At this time, the water level control valve 18 is also opened, and a part of the water in the steam separation tank 13 is drained to the condenser.

Furthermore, when the boiler is restarted, the high temperature fluid is filled in the rear transmission part 3, and as shown in FIG. 18, the time t ₀ gradually decreases as time elapses. Is small.

It should be noted that the times t _{0 to} t in FIGS.
₉ indicates the time of the above phenomenon as the subscript has a larger value with respect to the time t ₀ .

[0023]

The conventional hot banking boiler equipment start-up method has the following problems.

I) At startup, the high temperature fluid H ₁ , the low temperature fluid C ₁ , the high temperature fluid H ₂ , and the low temperature fluid C ₂ sequentially pass through the upper portion of the furnace wall tube 1a, so the furnace wall tube 1a is repeatedly heated and cooled. received,
Therefore, a large thermal stress is repeatedly generated at the connecting portion between the furnace wall tube 1a and the rear transmission portion 3.

Ii) In the furnace wall tube 1a, the steam separator 12 and the steam separation tank 13, a high-pressure high-temperature fluid H ₁ , a low-pressure low-temperature fluid C ₁ , a high-pressure high-temperature fluid H ₂ and a low-pressure low-temperature fluid are provided. C ₂
Since the fluid is sent in this order, the pressure fluctuation in the steam separation tank 13 is repeated, and therefore the water level _HL changes greatly repeatedly, and it takes time until the boiler recirculation pump 16 can be stably operated. In addition, the boiler pressure drops significantly during this period, resulting in a loss of startup time.

In view of the above-mentioned situation, the present invention prevents a large temperature difference from being repeatedly generated in the connecting portion between the furnace wall tube and the rear transmission part, suppresses the main steam pressure drop at the time of preparation for starting, and separates the steam / water separation tank. The purpose of the present invention is to provide a method for starting hot-boiled boiler equipment so that the water level in the system does not fluctuate repeatedly.

[0027]

The present invention is directed to a water supply pump, a economizer that heats water supplied by the water supply pump with exhaust gas, and water that is heated by the economizer using combustion gas. Furnace wall connected to the rear transmission part so as to generate steam, steam-water separating means for removing moisture from the steam generated in the furnace wall, and water separated by the steam-water separating means for saving the steam. When the boiler equipment provided with the boiler recirculation pump for circulating to the furnace is restarted after hot banking, the low temperature fluid remaining in the lower part of the furnace wall is extracted, and then the water supply pump is started.

[0028]

[Operation] After the low temperature fluid remaining in the lower part of the furnace wall is discharged to the outside of the system, water supply is started by the water supply pump, and at the same time, the high temperature fluid remaining in the upper part of the economizer is opened for a certain time by opening the steam vent valve. And then close the steam vent valve. Then, the high temperature fluid staying in the upper part of the furnace wall is sent to the steam-water separating means, and all the high temperature fluid in the furnace wall is sent to the steam-water separating means, and then the water is transferred from the furnace wall to the steam-water separating means. However, the low temperature fluid staying in the lower part of the furnace wall disappeared, the temperature of the furnace wall did not decrease much, and therefore the temperature difference between the connection part of the furnace wall and the rear transmission part became small, and this connection part Is not subject to repetitively changing thermal stress.

Further, by releasing the low temperature fluid staying in the lower part of the furnace wall and the high temperature fluid staying in the upper part of the economizer to the outside of the system, the fluid temperature of the steam separator after the start of the water supply greatly fluctuates. The internal pressure is relatively stable. Therefore, the water level in the steam separation means does not repeatedly change due to the fluctuation of the pressure in the steam separation means, and therefore the amount of water circulated from the steam separation means to the economizer by the boiler recirculation pump repeatedly changes. In no case, a stable water supply is provided.

[0030]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 7 show an embodiment of the present invention.

In the present embodiment, the blow pipe 21 is connected to a position near the inlet of the furnace wall pipe 1a of the connecting pipe 10 which connects the coal economizer 6 and the furnace wall pipe 1a, and a middle portion of the blow pipe 21 is conventionally used. A blow valve 22 is connected to the steam-removing valve 23 and a steam vent valve 23 is installed at the outlet of the economizer 6. In FIGS. 1 to 4, the same components as those shown in FIGS. 9 to 12 are designated by the same reference numerals.

Also in the present embodiment, at the time of hot banking, as shown in FIG.
Is closed, the feed water pump 8 and the boiler recirculation pump 16 are stopped, and a high-temperature high-temperature fluid H ₁ is supplied from the upper part of the furnace wall pipe 1a to the steam-water separator 12, the steam-water separation tank 13, and the steam-water separator 12. Stay in the upper part of the economizer 6, and the high temperature fluid H ₂ equivalent to the high temperature fluid H ₁ respectively accumulates in the upper part of the economizer 6, and the low temperature low temperature fluid C _{1 in} the lower part of the furnace wall tube 1a and the lower part of the economizer 6 A low temperature fluid having substantially the same pressure as that of the low temperature fluid C ₁ is retained in the space.

When the boiler is restarted from the hot banking state shown in FIG. 1, the blow valve 22 is opened in response to the boiler start command, and the low temperature fluid remaining in the lower part of the furnace wall tube 1a is opened. (Water) C ₁ is discharged into a blow tank (not shown) through the connecting pipe 10 and the blow pipe 21. The high temperature fluid H ₁ continues to stay in the upper part of the furnace wall tube 1a (see FIG. 2). The time for which the blow valve 22 is kept open varies depending on the amount of the low temperature fluid C ₁ , the pressure of the high temperature fluid H ₁ , and the like, but it is determined theoretically and empirically in advance by trial operation or the like.

When the low temperature fluid C _{1 in the} lower part of the furnace wall tube 1a is discharged from the blow tube 21, the blow valve 22 is closed and the driving of the water supply pump 8 is started to introduce water into the economizer 6 to supply water. Simultaneously with the start, the steam vent valve 23 at the outlet of the economizer 6 is opened for a certain time. Therefore, the high temperature fluid H ₂ in the economizer 6 is
Is discharged to the outside of the system from the economizer 6 through the vapor vent valve 23 by the low temperature fluid C _{2 under the} economizer 6. Since the low temperature fluid C ₁ is discharged from the lower portion of the furnace wall tube 1a, the water supply pump 8
For a while after starting up the high temperature fluid H above the furnace wall tube 1a
₁ is not extruded from the high temperature fluid H ₂ , and the furnace wall tube 1a
The state of staying in the upper part is continued (see FIG. 3).

When the water supply by the water supply pump 8 is further continued, the low temperature fluid C ₂ in the economizer 6 and the water (low temperature fluid) from the water supply pump 8 are also introduced from the lower part of the furnace wall tube 1a into the furnace wall tube 1a. When the water level of the low temperature fluid C ₂ in the furnace wall tube 1a increases, the high temperature fluids H ₂ and H ₁ are pushed up by the low temperature fluid C ₂ to the steam separator 12 and the steam separation tank 13. enter. In this case, until the high temperature fluids H ₁ and H ₂ are extruded from the upper part of the furnace wall tube 1a, a large temperature difference does not occur at the connection part between the furnace wall tube 1a and the rear transmission part 3.

From the upper part of the furnace wall tube 1a, high temperature fluids H ₁ and H _{2 are} introduced.
When There is exhausted the total amount, in Rokabekan 1a is filled with cryogen C _2, further by continuing the water supply from the water supply pump 8, a low temperature fluid C ₂ is Rokabekan 1a from the furnace wall tube outlet portion A It is discharged to the connecting pipe 11 through the water, is introduced into the steam separation tank 13 through the steam separator 12, and the water level of the steam separation tank 13 rises.

When the water level in the steam / water separation tank 13 reaches the upper limit, the water level control valve 18 is opened, a part of the water is discharged to the condenser, and the boiler recirculation pump 16 is started to activate the gas. The water in the water separation tank 13 is recirculated water supply pipe 15
After being sent to the water supply pipe 9, it is supplied to the economizer 6 together with the water from the water supply pump 8. At this time, air-water separation tank 1
The low temperature fluid C ₂ is continuously supplied to the inside of the interior 3 from the furnace wall pipe 1a, but since the water level control valve 18 is opened, the water level of the steam separation tank 13 gradually decreases to a predetermined water level. The water level control valve 18 is closed. Boiler recirculation pump 1
When 6 is started, the fuel burner 2 shown in FIG. 8 ignites,
Combustion is started.

FIG. 5 shows the situation when the boiler is restarted as described above.
6, FIG. 7, FIG. 13, FIG. 14, and FIG. 18, the water supply pump 8 is operated during hot banking of the boiler.
As shown in FIG. 3, after starting at time t ₀ , the constant water supply pump flow rate W _BFP is maintained and water supply is performed.

Further, as shown in FIG. 2, in the state where the high temperature fluid H ₁ stays in the upper part of the furnace wall tube 1a, as shown in FIG.
The high temperature fluid H ₂ in the economizer 6 flows into the lower part of the furnace wall tube 1a, and the high temperature fluids H ₁ and H ₂ are further extruded from the furnace wall tube 1a by the low temperature fluid C ₂ from the economizer 6. As shown in FIG. 5, the temperature T of the furnace wall tube outlet portion A decreases at a slow speed, and the time t ₁₁ at which the low temperature fluid C ₂ reaches the furnace wall tube outlet portion A is t _11.
After that, the temperature at the outlet A of the furnace wall tube gradually decreases without decreasing relatively rapidly. Therefore, the temperature T at the outlet A of the furnace wall tube does not repeat high temperature and low temperature conditions and the rate of temperature change is small, and the fluctuating heat at the connection between the end of the furnace wall tube 1a and the end of the rear transmission section 3 is changed. Since the stress does not act repeatedly, only static thermal stress acts on the connection portion, and the connection portion is unlikely to be damaged.

When all of the high temperature fluids H ₁ and H ₂ in the furnace wall tube 1a are discharged to the outside of the furnace wall tube 1a, the low temperature fluid C ₂ is subsequently discharged from the furnace wall tube 1a and the low temperature fluid C ₂ becomes Steam separator 12
And flows into the steam separation tank 13. Therefore, in FIG.
As shown in FIG. 7, the pressure P in the steam-water separator 12 slowly decreases, and as shown in FIG. 7, the water level _HL of the steam-water separation tank 13 also rises after time t ₁₅ , and the boiler recirculation pump 16 turns on. After the time t _{16 when} starting (after t _{9 in} FIG. 14), it is lowered and is maintained at a preset constant water level.

Since the pressure P in the steam / water separator 12 drops relatively slowly, the water level in the steam / water separation tank 13 does not repeatedly fluctuate largely due to pressure fluctuations, but is discharged from the boiler recirculation pump 16. Recirculation water supply pipe 15
The flow rate of the water supplied from the water supply pipe 9 to the furnace wall pipe 1a is stable.

Each time is t ₁₁ , t ₁₃ , t ₁₅ , t ₁₄ , t ₁₂ ,
The order of t ₁₆ represents the time when the above phenomenon occurs with reference to the time t _{0 of} FIG. 13.

The present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0045]

According to the method for starting a hot-banked boiler facility according to the present invention, the thermal stress that fluctuates does not repeatedly act on the connection portion between the furnace wall and the rear transmission portion, so that the connection portion is less likely to be damaged. Also, since the pressure in the steam separation tank does not fluctuate repeatedly, the water level in the steam separation tank also does not fluctuate repeatedly due to pressure fluctuations. The flow rate of water supplied to the furnace wall pipe through the water supply pipe is stabilized, and the low-temperature fluid discharge can suppress various internal effects such as reduction in internal pressure and main steam pressure.

[Brief description of drawings]

FIG. 1 shows an outline of the arrangement of equipment used for carrying out the method of the present invention, and a high temperature fluid is at the upper part of the furnace wall tube and an upper part of the economizer, and a low temperature fluid is at the lower part of the furnace wall tube and the lower part of the economizer. It is a schematic diagram which shows a state.

FIG. 2 shows an outline of the arrangement of equipment used for carrying out the method of the present invention, in which the high temperature fluid is at the upper part of the furnace wall tube and the upper part of the economizer, and the low temperature fluid is at the lower part of the economizer and the lower part of the furnace wall tube FIG. 6 is a schematic diagram showing a state in which the low temperature fluid that has stagnated is blown out of the system.

FIG. 3 is a schematic diagram showing an outline of the arrangement of equipment used for carrying out the method of the present invention, and showing a state in which the high temperature fluid is in the upper and lower portions of the furnace wall tube and the low temperature fluid is in the entire economizer.

FIG. 4 is a schematic diagram showing an outline of the arrangement of equipment used for carrying out the method of the present invention and showing a state in which a low temperature fluid is present in both the furnace wall tube and the economizer.

FIG. 5 is a graph showing the relationship between temperature at the furnace wall tube outlet and time when the method of the present invention is carried out.

FIG. 6 is a graph showing the relationship between the pressure in the steam separator and time when carrying out the method of the present invention.

FIG. 7 is a graph showing the relationship between the water level of a steam separation tank and time when the method of the present invention is carried out.

FIG. 8 is a side view showing an outline of a boiler to which the method of the present invention or the conventional method is applied.

FIG. 9 shows an outline of the arrangement of equipment used when performing a conventional method, and shows a state in which a high temperature fluid is at the upper part of the furnace wall tube and the upper part of the economizer and a low temperature fluid is at the lower part of the furnace wall tube and the lower part of the economizer. It is a schematic diagram which shows.

FIG. 10 is a schematic diagram showing an outline of the arrangement of equipment used when performing a conventional method, and showing a state in which a high temperature fluid is at the lower part of the furnace wall tube and a low temperature fluid is at the upper part of the furnace wall tube and the upper part of the economizer. is there.

FIG. 11 is a schematic diagram showing an outline of the arrangement of equipment used when performing a conventional method, and showing a state in which a high temperature fluid is in the upper part of the furnace wall tube and a low temperature fluid is in the lower part of the furnace wall tube and the entire economizer. is there.

FIG. 12 is a schematic diagram showing an outline of arrangement of equipment used when performing a conventional method and showing a state in which a low temperature fluid is present in the entire furnace wall tube and the entire economizer.

FIG. 13 is a graph showing the relationship between the feed water pump flow rate and time when the conventional method or the method of the present invention is performed.

FIG. 14 is a graph showing the relationship between recirculation pump flow rate and time when the conventional method or the method of the present invention is performed.

FIG. 15 is a graph showing the relationship between the temperature at the furnace wall tube outlet and time when the conventional method is carried out.

FIG. 16 is a graph showing the relationship between the pressure in the steam separator and time when the conventional method is carried out.

FIG. 17 is a graph showing the relationship between the water level of a steam separation tank and time when the conventional method is carried out.

FIG. 18 is a graph showing the relationship between the temperature of the rear transmission part and the time when the conventional method is performed.

[Explanation of symbols]

1 Furnace wall 3 Post-transmission section 6 Coal saver 8 Water supply pump 12 Steam separator (steam separation means) 13 Steam separation tank (steam separation means) 16 Boiler recirculation pump H ₁ , H ₂ high temperature fluid (steam) ) C ₁ , C ₂ low temperature fluid (water)

Claims (1)

[Claims] 1. A water supply pump, a economizer that heats the water supplied by the water pump with exhaust gas, and a post-conduction system that heats the water heated by the economizer with combustion gas to generate steam. Part connected to the furnace wall, steam-water separating means for removing water from steam generated in the furnace wall, and a boiler recirculation pump for circulating the water separated by the steam-water separating means to the economizer. When restarting the boiler equipment provided with and after hot banking, after extracting the low-temperature fluid remaining in the lower part of the furnace wall, the hot water supply pump is activated, starting method.