Bus pipe thermal system for realizing machine-furnace decoupling and operation method
Technical Field
The invention belongs to the field of thermal power generation, and particularly relates to a bus pipe thermal system for realizing machine-furnace decoupling and an operation method.
Background
At present, large-capacity thermal power generating units (more than or equal to 300MW) are designed to operate in a unit system mode, namely, one boiler is matched with 1 specific steam turbine, the steam turbine drives a generator to generate electricity, and each independent unit basically presents a weak link state except a public part.
Compared with the main control unit, when the boiler equipment needs to be overhauled, has a fault, needs to be thermally reserved by a power grid dispatching unit or needs to be shut down, the corresponding steam turbine and the corresponding generator are forced to stop running simultaneously. This greatly affects unit flexibility to a certain extent, limiting the overall peak shaving capacity of the plant unit. In addition, because the boiler equipment needs to be maintained to work above a certain load lower limit value, the unit system operation mode greatly limits the lowest load value of the unit under the deep peak regulation operation condition, and the flexibility of the unit under the deep peak regulation operation condition is reduced.
On the other hand, with the continuous increase of the capacity of a novel clean energy power generation system such as photoelectricity and wind power, the fluctuation of a power grid is increased, and with the continuous development of national economy and the change of a power utilization structure, a power system also faces the contradiction that the peak-to-valley difference of the power grid is large and the peak regulation capability is insufficient, so that the power grid provides higher requirements for the thermal power generating unit to participate in peak regulation and even deep peak regulation.
Disclosure of Invention
The invention aims to provide a main pipe control thermodynamic system and an operation method for realizing machine-furnace decoupling, so that the flexibility of a unit under a deep peak regulation operation condition and the unit power generation amount of a boiler device under an accident state are improved.
The invention is realized by adopting the following technical scheme:
a main pipe thermal system for realizing machine-furnace decoupling comprises a steam-water system of a steam turbine set and an additional system; wherein, add the system and include: the system comprises a main steam communication main pipe, a cold reheating section steam communication main pipe, a hot reheating section steam communication main pipe, a deaerator steam extraction communication main pipe, a three-section steam extraction communication main pipe, a final water supply communication main pipe, a medium pressure cylinder steam exhaust communication main pipe, a condenser hot well water pouring pump and a condenser hot well water communication main pipe;
the main steam communication main pipe is respectively connected to a superheater outlet main steam pipeline of each unit boiler, a connection point is arranged on a pipeline between a boiler superheater outlet valve group and a steam turbine steam inlet valve group, and a single machine to main steam communication main pipe control and isolation valve group is arranged between the connection point and the main steam communication main pipe;
the cold reheating section steam communication main pipe is connected with reheating cold section steam pipelines of each unit boiler, the connection point is arranged on a pipeline between a high-pressure cylinder outlet of a steam turbine and a steam inlet valve bank of a boiler reheater, and a single machine to cold reheating section steam communication main pipe control and isolation valve bank is arranged between the connection point and the cold reheating section steam communication main pipe;
the hot reheating section steam communication main pipe is connected with reheating heating section steam pipelines of the boiler of each unit, the connection point is arranged on a pipeline between a boiler reheater steam outlet valve bank and an inlet of a steam turbine intermediate pressure cylinder, and a single machine to hot reheating section steam communication main pipe control and isolation valve bank is arranged between the connection point and the hot reheating section steam communication main pipe;
the deaerator steam extraction communication main pipe is connected with a pipeline from a steam turbine deaerator steam extraction to a deaerator, a connection point is arranged on the pipeline between a steam turbine deaerator steam extraction valve group and a deaerator steam inlet valve group, and a single machine to a deaerator steam extraction communication main pipe control and isolation valve group is arranged between the connection point and the deaerator steam extraction communication main pipe;
the three-section steam extraction communication main pipe is connected with a pipeline from three-section steam extraction to a third-stage high-pressure heater of each unit, a connection point is arranged on the pipeline between the three-section steam extraction valve group and a steam inlet valve group of a third-stage high-pressure heater system, and a single-unit to three-section steam extraction communication main pipe isolation and control valve group is arranged between the connection point and the three-section steam extraction communication main pipe;
the final water supply communication main pipe is connected with boiler water supply pipelines of the outlets of the high-pressure heater systems of the units, a connection point is arranged on the boiler water supply pipeline of the control valve group for isolating the outlet of the high-pressure heater system from the inlet of the boiler water supply economizer, and a single machine to the control valve group of the final water supply communication main pipe are arranged between the connection point and the final water supply communication main pipe;
the steam exhaust and communication main pipe of the intermediate pressure cylinder is connected with a steam inlet pipeline from the steam exhaust of the intermediate pressure cylinder to the low pressure cylinder of the steam turbine, a connection point is arranged on a pipeline between an outlet of the intermediate pressure cylinder of the steam turbine and an inlet valve group of the low pressure cylinder of the steam turbine, and a control and isolation valve group from a single machine to the steam exhaust and communication main pipe of the intermediate pressure cylinder is arranged between the connection point and the steam exhaust and communication main pipe of the intermediate pressure cylinder;
an inlet of a water pouring pump of the condenser hot well is led out of the condenser hot well through a bypass, an outlet pipeline is provided with a water pouring pump isolating and controlling valve set, and a three-way pipe is arranged behind a valve and is connected with a condensed water communicating main pipe of the hot well;
the condenser hot well water communicating main pipe is connected with condenser hot well condensed water pipelines of each unit, the connecting point is arranged on the condensed water pipeline between a hot well outlet and a condensed water pump, a single unit is arranged on the pipeline to the hot well condensed water communicating main pipe isolation and control valve bank, and the valve bank is arranged between the three-way pipe and the connecting point.
A further improvement of the present invention is that the add-on system further comprises: the high-pressure cylinder steam extraction communication main pipe is connected with pipelines of high-pressure cylinder steam extraction to high-pressure heater systems of the steam turbines of all the units, a connecting point is arranged on the pipeline between the steam extraction valve group of the high-pressure cylinder of the steam turbine and the steam inlet valve group of the high-pressure heater systems, and a single-machine high-pressure cylinder steam extraction communication main pipe control and isolation valve group is arranged between the connecting point and the high-pressure cylinder steam extraction communication main pipe.
A further improvement of the present invention is that the add-on system further comprises: the low-pressure cylinder extraction and communication main pipe is connected with a steam extraction pipeline of the low-pressure cylinder of the steam turbine, the connection point is arranged on the pipeline between the steam extraction valve set of the low-pressure cylinder of the steam turbine and the steam inlet valve set of the low-pressure heater system, and a single-machine to low-pressure cylinder extraction and communication main pipe control and isolation valve set is arranged between the connection point and the low-pressure cylinder extraction and communication main pipe.
The invention is further improved in that the steam-water system of the steam turbine set comprises boilers 1, 2, … … and n, wherein the outlet of a superheated steam pipeline of each boiler is communicated with the steam inlet of a high-pressure cylinder, the steam outlet of a high-pressure cylinder is communicated with the inlet of a reheated steam pipeline of the boiler, the outlet of the reheated steam pipeline of the boiler is communicated with the steam inlet of an intermediate-pressure cylinder, the steam outlet of the intermediate-pressure cylinder is communicated with the steam inlet of a low-pressure cylinder, the steam outlet of the low-pressure cylinder is communicated with a condenser, the steam outlet of the high-pressure cylinder is communicated with the steam inlet of a high-pressure heating system, the steam outlet of the intermediate-pressure cylinder is communicated with the steam inlet of a deaerator, the steam outlet of the low-pressure cylinder is communicated with the steam inlet of a low-pressure heating system, and the condenser, the condensate pump, the low-pressure heating system, the deaerator and the water feeding pump are sequentially communicated with the water inlet and the water outlet of the high-pressure heating system, and the water outlet of the high-pressure heating system is communicated with the inlet of a water feeding pipeline of the boiler.
The invention is further improved in that when only two units are provided, the two units are connected by using a communicating pipe equipped with an isolation valve group and a control valve group.
An operation method of a bus-controlled thermodynamic system for realizing machine-furnace decoupling is based on the bus-controlled thermodynamic system for realizing machine-furnace decoupling, and takes the shutdown of a boiler of a unit 1 in a plurality of units as an example, and comprises the following steps:
when the No. 1 boiler is stopped, closing a main steam isolation valve group, a reheating cold section steam isolation valve group and a hot section steam isolation valve group of the No. 1 boiler to prevent steam from flowing back to the stopped boiler; opening a main steam communication main pipe control and isolation valve group of the boiler, and supplying main steam to the No. 1 steam turbine and the steam turbine of the unit by the boilers of other units at the same time; opening a control and isolation valve group of a cold reheating section steam communication main pipe, enabling cold reheating steam of the No. 1 unit to enter the cold reheating section steam communication main pipe, and heating the reheating cold section steam of the No. 1 unit by boilers of other units; opening a hot reheating section steam communication main pipe control and isolation valve group, and supplying reheating section steam to the No. 1 steam turbine and a middle pressure cylinder of the unit by boilers of other units; closing a steam inlet isolation and control valve of the No. 1 high-pressure heater system, opening a steam extraction communication main pipe control and isolation valve group of the No. 1 high-pressure cylinder, reversely sending the extracted steam of the high-pressure cylinder to an adjacent unit, and not operating the No. 1 high-pressure heater system; closing an isolation and control valve of a third-stage high-pressure heater of the No. 1 machine, opening a control and isolation valve group of a three-section steam extraction communication main pipe of the No. 1 machine, reversely sending the three-section steam extraction of the No. 1 machine to an adjacent machine set, and not operating the third-stage high-pressure heater of the No. 1 machine; closing a steam inlet isolation and control valve of the machine deaerator No. 1, opening a steam extraction communication main pipe control and isolation valve group of the machine deaerator No. 1, pumping steam of the deaerator No. 1 and transferring the steam to an adjacent machine set, and not operating the machine deaerator No. 1; opening a steam exhaust communication main pipe control and isolation valve group of the No. 1 intermediate pressure cylinder, enabling the steam exhaust of the No. 1 intermediate pressure cylinder of the steam turbine to enter low pressure cylinders of the steam turbines of other units to do work, enabling the No. 1 low pressure cylinder of the steam turbine to be in a lowest steam inlet flow state, enabling the steam inlet flow to meet the lowest cooling steam requirement of the low pressure cylinder, and operating the unit which is transformed into the low pressure cylinder with zero output of the low pressure cylinder in a mode of zero output of the low pressure cylinder; closing a steam inlet isolation and control valve of the No. 1 low-pressure heater system, opening a low-pressure cylinder to draw steam and communicate with a main pipe control and isolation valve, reversely sending the low-pressure cylinder to other adjacent units, and not operating the No. 1 low-pressure heater system; opening condenser hot well water pouring pump and corresponding control, isolation valves, closing hot well condensate water normal control, isolation valves, closing hot well water communication main pipe control, isolation valves, pouring the condensate water of No. 1 machine to hot well water communication main pipe, to other unit hot wells, the condensate water of No. 1 machine enters into other unit low pressure heater systems to heat.
A further improvement of the invention is that boiler outages refer to maintenance, failure, unit two shift operation, unit hot standby, and all other situations where there is a planned or unexpected outage of the boiler plant.
The invention is further improved in that the valve group refers to a regulating valve and an isolating valve which are used, and the valves are electrically operated valves, pneumatic valves, hydraulic valves and manual valves.
Compared with the prior art, the invention has at least the following beneficial technical effects:
1. by using the invention, under the operating condition of deep peak regulation, the heat recovery system of the whole blowing-out unit can be out of work, the steam extracted by the high and medium pressure cylinders is totally poured to the heat recovery systems of other units, the blowing-out unit only has the high and medium pressure cylinders to do work externally, the low pressure cylinder is in the lowest steam inlet flow state or the zero output state, the steam inlet amount of the low pressure cylinder of the steam turbine of the blowing-out unit is totally sent back to the low pressure cylinders of other units, and the actual operating efficiency of the low pressure cylinder averaged by a plurality of units is improved.
2. By adopting the method, when partial unit boilers are shut down, are in hot standby or are in two-shift operation, the steam turbine of the blowing-out unit can obtain main and reheat steam by controlling the main pipes and the inter-unit connecting valve group, and the cold and reheat steam of the blowing-out unit is recovered, so that the blowing-out is not stopped.
3. By adopting the method, the regenerative system of the furnace shutdown unit does not work, the exhaust steam of the intermediate pressure cylinder is reversely sent to the low pressure cylinders of other units, and the average low pressure cylinder operation efficiency of a plurality of units is improved.
4. By using the method, the unit can realize further machine-furnace decoupling under the operating condition of 'less furnaces and multiple machines', and further reduce the output power rate of the steam turbine generator unit under the operating condition of deep peak shaving under the normal operating condition of the boiler in operation.
Drawings
Fig. 1 is a schematic structural view of the present invention.
Reference numbers (Pn refers to pump of nth unit, Vn refers to valve of nth unit):
pn-1, a water supply pump,
pn-2, a condensate pump,
pn-3, condenser hot well water pouring pump
Vn-1, a main steam communication main pipe control and isolation valve bank,
vn-2, a boiler main steam control and isolation valve bank,
vn-3, a reheating cold section steam is communicated with a main pipe control and isolation valve bank,
vn-4, a reheating cold section steam control and an isolation valve bank,
vn-5, a hot reheating section steam is communicated with a main pipe control and isolation valve bank,
vn-6, a reheating hot section steam control and an isolation valve bank,
vn-7, a high-pressure cylinder steam inlet control and an isolation valve bank,
vn-8, a middle pressure cylinder steam inlet control and an isolation valve group,
vn-9, a low-pressure cylinder steam inlet control and an isolation valve bank,
vn-10, a high-pressure cylinder steam extraction control and isolation valve bank,
vn-11, a deaerator steam extraction control and an isolation valve bank,
vn-12, three-stage steam extraction control and isolation valve bank,
vn-13, a high pressure heater system steam inlet control and an isolation valve set,
vn-14, a deaerator steam inlet control and an isolation valve bank,
vn-15, third-stage heater steam inlet control and isolation valve group,
vn-16, an inlet control and isolation valve bank of a boiler water supply economizer,
vn-17, a final water supply communication main pipe control and isolation valve group,
vn-18, a high-pressure cylinder steam extraction communication main pipe control and isolation valve group,
vn-19, a deaerator steam extraction and communication main pipe control and isolation valve bank,
vn-20, three-section steam extraction and communication main pipe control and isolation valve bank,
vn-22, a condenser hot well water pouring pump isolation and control valve bank,
vn-23, a condenser hot well water communication main pipe isolation and control valve group,
vn-24, the exhaust of the intermediate pressure cylinder is communicated with a main pipe isolation and control valve group,
vn-25, a low-pressure cylinder steam extraction control and isolation valve bank,
vn-26, a low-pressure cylinder steam extraction communication main pipe control and isolation valve group,
vn-27, a low-pressure heater system steam inlet control and an isolation valve group,
vn-28, a water inlet control of a low-pressure heater system and an isolation valve group.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
Referring to fig. 1, the main pipe thermal system for realizing machine-to-furnace decoupling provided by the invention comprises a conventional boiler, a steam-water system of a steam turbine set and an additional system. Wherein, add the system and include: the system comprises a main steam communication main pipe, a cold reheating section steam communication main pipe, a hot reheating section steam communication main pipe, a high-pressure cylinder steam extraction communication main pipe, a deaerator steam extraction communication main pipe, a three-section steam extraction communication main pipe, a final water supply communication main pipe, an intermediate pressure cylinder steam exhaust communication main pipe, a low-pressure cylinder steam extraction communication main pipe, a condenser hot well water pouring pump, a condenser hot well water communication main pipe and a corresponding control and shutoff valve set.
Wherein, the steam-water system of the steam turbine set comprises boilers 1, 2, … … and n, the outlet of the superheated steam pipeline of each boiler is communicated with the steam inlet of the high-pressure cylinder, the steam outlet of the high-pressure cylinder is communicated with the inlet of the reheated steam pipeline of the boiler, the outlet of the reheated steam pipeline of the boiler is communicated with the steam inlet of the intermediate pressure cylinder, the steam outlet of the intermediate pressure cylinder is communicated with the steam inlet of the low-pressure cylinder, the steam outlet of the low-pressure cylinder is communicated with the condenser, the steam outlet of the high-pressure cylinder is communicated with the steam inlet of the high-pressure heating system, the steam outlet of the intermediate pressure cylinder is communicated with the steam inlet of the deaerator, the steam outlet of the low-pressure cylinder is communicated with the steam inlet of the low-pressure heating system, and the condenser, the condensate pump, the low-pressure heating system, the deaerator and the water feeding pump are sequentially communicated with the water inlet and the water outlet of the high-pressure heating system, and the water outlet of the high-pressure heating system is communicated with the inlet of a water feeding pipeline of the boiler.
The connection mode of the main steam communication main pipe in the additionally-arranged system is as follows: the main steam communication main pipe is respectively connected to a superheater outlet main steam pipeline of each unit boiler, a connection point is arranged on a pipeline between a boiler superheater outlet valve bank Vn-2 and a steam turbine steam inlet valve bank Vn-7, and a single machine and a main steam communication main pipe control and isolation valve bank Vn-1 are arranged between the connection point and the main steam communication main pipe.
The connection mode of the steam communication main pipe of the cold reheating section in the additionally-arranged system is as follows: the cold reheating section steam communication main pipe is connected with reheating cold section steam pipelines of unit boilers, the connection point is arranged on a pipeline between a steam turbine high-pressure cylinder outlet and a boiler reheater steam inlet valve bank Vn-4, and a single machine to cold reheating section steam communication main pipe control and isolation valve bank Vn-3 is arranged between the connection point and the cold reheating section steam communication main pipe.
The connection mode of the hot reheating section steam communication main pipe in the additionally-arranged system is as follows: the hot reheating section steam communication main pipe is connected with reheating hot section steam pipelines of unit boilers, the connection point is arranged on a pipeline between a boiler reheater steam outlet valve bank Vn-6 and a steam turbine intermediate pressure cylinder steam inlet valve bank Vn-8, and a single machine to hot reheating section steam communication main pipe control and isolation valve bank Vn-5 is arranged between the connection point and the hot reheating section steam communication main pipe.
The connecting mode of the high-pressure cylinder steam extraction communication main pipe in the additionally-arranged system is as follows: the high-pressure cylinder steam extraction communication main pipe is connected with pipelines of high-pressure cylinder steam extraction to high-pressure heater systems of the turbines of the units, a connection point is arranged on the pipeline between the steam extraction valve bank Vn-10 of the high-pressure cylinder steam extraction valve bank of the turbine and the steam inlet valve bank Vn-13 of the high-pressure heater systems, and a single-machine high-pressure cylinder steam extraction communication main pipe control and isolation valve bank Vn-18 is arranged between the connection point and the high-pressure cylinder steam extraction communication main pipe.
The connecting mode of the deaerator steam extraction communication main pipe in the additionally-arranged system is as follows: the deaerator steam extraction communication mother pipe is connected with a pipeline from a steam turbine deaerator steam extraction to a deaerator, a connection point is arranged on the pipeline between a steam turbine deaerator steam extraction valve bank Vn-11 and a deaerator steam inlet valve bank Vn-14, and a single machine is arranged between the connection point and the deaerator steam extraction communication mother pipe, and a control valve bank Vn-19 and an isolation valve bank are arranged between the connection point and the deaerator steam extraction communication mother pipe.
The connection mode of the three-section steam extraction communication main pipe in the additionally-arranged system is as follows: the three-section steam extraction communication main pipe is connected with a pipeline from the three-section steam extraction of each unit to the third-stage high-pressure heater, a connection point is arranged on the pipeline between the three-section steam extraction valve bank Vn-12 and the steam inlet valve bank Vn-15 of the third-stage high-pressure heater system, and a single machine to the isolation and control valve bank Vn-20 of the three-section steam extraction communication main pipe is arranged between the connection point and the three-section steam extraction communication main pipe.
The final water supply communication main pipe in the additionally-arranged system is connected in a mode that: the final water supply communication main pipe is connected with boiler water supply pipelines at the outlets of the high-pressure heater systems of the units, the connection point is arranged on the boiler water supply pipeline of the control valve bank Vn-16 for isolating the outlet of the high-pressure heater system from the inlet of the boiler water supply economizer, and a single machine is arranged between the connection point and the final water supply communication main pipe to the control valve bank Vn-17 of the final water supply communication main pipe.
The connection mode of the steam exhaust and communication main pipe of the medium pressure cylinder in the additionally-arranged system is as follows: the intermediate pressure cylinder steam exhaust communication main pipe is connected with a steam exhaust pipeline from an intermediate pressure cylinder to a low pressure cylinder of the steam turbine, a connection point is arranged on a pipeline between a steam exhaust port of the intermediate pressure cylinder of the steam turbine and a steam inlet valve group Vn-9 of the low pressure cylinder of the steam turbine, and a single-machine to intermediate pressure cylinder steam exhaust communication main pipe control and isolation valve group Vn-24 is arranged between the connection point and the intermediate pressure cylinder steam exhaust communication main pipe.
The connecting mode of the steam extraction and communication main pipe of the low-pressure cylinder in the additionally-arranged system is as follows: the low-pressure cylinder steam extraction communication main pipe is connected with a steam extraction pipeline of the steam turbine low-pressure cylinder, the connection point is arranged on the pipeline between the steam extraction valve bank Vn-25 of the steam turbine low-pressure cylinder and the steam inlet valve bank Vn-27 of the low-pressure heater system, and a single-machine to low-pressure cylinder steam extraction communication main pipe control and isolation valve bank Vn-26 is arranged between the connection point and the low-pressure cylinder steam extraction communication main pipe.
The connection mode of the water pouring pump of the condenser hot well in the additionally-arranged system is as follows: an inlet of a water pouring pump Pn-3 of the condenser hot well is led out from the condenser hot well through a bypass, an outlet pipeline is provided with a water pouring pump isolation and control valve bank Vn-22, a three-way pipe is arranged behind the valve and is connected with a hot well condensed water communication main pipe.
The connection mode of the hot well condensed water communication main pipe in the additionally-arranged system is as follows: the hot well condensed water communication main pipe is connected with the hot well condensed water pipeline of each unit condenser, the connection point is arranged on the condensed water pipeline between the hot well outlet and the condensed water pump, a single unit is arranged on the pipeline to the hot well condensed water communication main pipe isolation and control valve bank Vn-23, and the valve bank is arranged between the three-way pipe and the connection point.
The invention provides an operation method of a bus-pipe thermal system for realizing machine-furnace decoupling, which takes the shutdown of a boiler of a No. 1 unit in a plurality of units as an example and comprises the following operation contents:
when the No. 1 boiler is stopped, the main steam isolation valve group V1-2, the cold reheat section steam isolation valve group V1-4 and the hot reheat section steam isolation valve group V1-6 of the No. 1 boiler are closed, and steam is prevented from flowing back to the stopped boiler. Opening a main steam communication main pipe control and isolation valve group V1-1 of a boiler of the No. 1 unit, and opening main steam communication main pipe control and isolation valve groups Vm-1(m is 2,3,4, …, n is the number of other running units and can be a plurality of units) of boilers of other running units, wherein the boilers of other units can simultaneously supply main steam for a steam turbine of the No. 1 unit and a steam turbine of the local unit; opening a cold reheating section steam communication main pipe control and isolation valve group V1-3, enabling cold reheating steam of the No. 1 unit to enter the cold reheating section steam communication main pipe, opening other running unit cold reheating section steam communication main pipe control and isolation valve group Vm-3, and heating the reheating cold section steam of the No. 1 unit by boilers of other units; opening a steam communication main pipe control and isolation valve group V1-5 of the hot reheating section, opening steam communication main pipe control and isolation valve groups Vm-5 of the hot reheating section of other running units, and supplying reheating heating section steam to a No. 1 steam turbine and a middle pressure cylinder of the unit by boilers of other units; closing a steam inlet isolation and control valve V1-13 of the No. 1 high-pressure heater system, opening a steam extraction and communication main pipe control and isolation valve group V1-18 of the No. 1 high-pressure cylinder, reversely sending the extracted steam of the high-pressure cylinder to an adjacent unit, and not operating the No. 1 high-pressure heater system; closing a steam inlet isolation and control valve V1-15 of the third-stage high-pressure heater of the No. 1 machine, opening a three-section steam extraction communication main pipe control and isolation valve group V1-20 of the No. 1 machine, reversely sending the three-section steam extraction of the No. 1 machine to an adjacent machine set, and not operating the third-stage high-pressure heater of the No. 1 machine; closing a steam inlet isolation and control valve V1-14 of the No. 1 deaerator, opening a steam extraction communication main pipe control and isolation valve group V1-19 of the No. 1 deaerator, and transferring the steam extraction of the deaerator to an adjacent unit, wherein the No. 1 deaerator does not run; opening a steam exhaust communication main pipe control and isolation valve group V1-24 of the No. 1 intermediate pressure cylinder, enabling the steam exhaust of the No. 1 intermediate pressure cylinder of the steam turbine to enter low pressure cylinders of other units of steam turbines to do work, enabling the No. 1 low pressure cylinder of the steam turbine to be in the lowest steam inlet flow state, enabling the steam inlet flow to meet the lowest cooling steam requirement of the low pressure cylinder, and enabling the unit which is transformed into the low pressure cylinder with zero output to operate in the mode of zero output of the low pressure cylinder; closing the steam inlet isolation and control valve V1-27 of the No. 1 machine low-pressure heater system, opening the low-pressure cylinder steam extraction communication main pipe control and isolation valve group V1-26, and sending the low-pressure cylinder steam extraction to other adjacent machine sets in a backward mode, wherein the No. 1 machine low-pressure heater system does not operate; opening a condenser hot well water pouring pump P1-3 and a corresponding control and isolation valve group V1-22, closing a low-pressure heater system water inlet control and isolation valve group V1-28, closing a hot well water communication main pipe control and isolation valve group V1-23, pouring all condensed water of the machine No. 1 to a hot well water communication main pipe to other machine set hot wells, and enabling the condensed water of the machine No. 1 to enter other machine set low-pressure heater systems for heating.
Table 1 shows the comparison between the operation states of the main valves and the equipment of the system under the conventional unit system operation condition and the operation states of the main valves and the equipment of the system under the less-furnace multi-machine operation condition by using the method of the present invention.
Table 1 takes two units as an example, the unit system operation is that the two units both operate normally, the less-furnace multi-machine system operation is that the No. 1 unit boiler stops operating, and the No. 2 unit boiler supplies main steam to the No. 1 unit turbine and the No. 2 unit turbine at the same time.
The invention provides a header pipe thermal system for realizing machine-furnace decoupling and an operation method thereof. By using the invention, under the operating condition of deep peak regulation, the heat recovery system of the whole blowing-out unit can be out of work, the steam extracted by the high and medium pressure cylinders is totally poured to the heat recovery systems of other units, the blowing-out unit only has the high and medium pressure cylinders to do work externally, the low pressure cylinder is in the lowest steam inlet flow state or the zero output state, the steam inlet amount of the low pressure cylinder of the steam turbine of the blowing-out unit is totally sent back to the low pressure cylinders of other units, and the actual operating efficiency of the low pressure cylinder averaged by a plurality of units is improved.