Heat utilization system of slag cooler and low-temperature economizer of circulating fluidized bed heat supply unit
Technical Field
The utility model relates to a circulating fluidized bed boiler technical field, concretely relates to circulating fluidized bed heat supply unit slag cooler and low temperature economizer heat utilization system.
Background
The circulating fluidized bed heat supply unit has the advantages of wide fuel adaptability, high combustion efficiency, high-efficiency desulfurization and NOxLow emission, simple structure, convenient operation and the like, thereby being widely applied in the field of electric power. At present, in the thermal production operation of the circulating fluidized bed boiler, a condensed water pair is generally adoptedThe heat of a slag cooler and a low-temperature economizer in the boiler system is absorbed, and the recovered heat is transmitted to a condensate system.
However, the production mode has certain defects, namely, the heat recovered by the slag cooler and the low-temperature economizer has lower heat efficiency under the pure condensation working condition of the power station; and secondly, the reduction of the through flow of the condensed water of the low-pressure heater leads to the reduction of the condensed steam extraction amount, the operation efficiency of the low-pressure heater of the steam turbine system can be reduced, and then the temperature of the condensed water to the outlet water of the deaerator is reduced, so that the heat efficiency of the power station is influenced. Therefore, the heat recovery systems of the slag cooler and the low-temperature economizer of the circulating fluidized bed boiler need to be redesigned and modified.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model provides a circulating fluidized bed heat supply unit slag cooler and low temperature economizer heat utilization system can improve the waste heat utilization ratio of slag cooler and low temperature economizer, improves low pressure feed water heater's operating efficiency and power station thermal efficiency.
In order to realize the technical purpose, the utility model discloses a technical scheme is: the heat utilization system comprises a slag cooler, a low-temperature economizer, a #3 low-pressure heater, a #2 low-pressure heater and a #1 low-pressure heater, wherein the #3 low-pressure heater, the #2 low-pressure heater and the #1 low-pressure heater are used for heating condensed water step by step, the condensed water is heated by the #3 low-pressure heater and then is conveyed to the slag cooler, and the slag cooler and the low-temperature economizer are connected in series through a slag cooler water outlet pipeline; still contain the plate heat exchanger that is used for city heat supply network circulating water heat transfer, plate heat exchanger heat supply network side is established ties with city heat supply network circulation pipeline through manual valve of plate heat exchange network side inflow and manual valve of plate heat exchange network side play water respectively, plate heat exchanger passes through low temperature economizer outlet pipe way and establishes ties with low temperature economizer, and plate heat exchanger's condensate side inlet end and condensate side outlet end have the board to trade the bypass pipeline in parallel, are provided with respectively on plate heat exchanger's condensate side inlet end, condensate side outlet end, the board trade bypass pipeline that the board trades condensate side inflow motorised valve, the board trades condensate side and goes out the water motorised valve, the board trades bypass inlet motorised valve, the delivery port that bypass pipeline was traded to the board communicates with #1 low pressure feed water heater and #2 low pressure feed water heater's inlet pipeline respectively.
Furthermore, a slag cooler water outlet manual valve is arranged at the slag cooler water outlet, the slag cooler water outlet manual valve is respectively connected with the low-temperature economizer water inlet pipeline and the slag cooler water return to low-pressure addition pipeline, and the slag cooler water return to low-pressure addition pipeline is provided with a slag cooler water return to low-pressure addition manual valve and a slag cooler water return to low-pressure addition electric adjusting valve.
Furthermore, the water inlet pipeline of the slag cooler is sequentially provided with a slag cooler water inlet electric adjusting valve, a slag cooler water inlet manual valve and a flowmeter along the flow direction of condensed water, and the water inlet of the slag cooler water inlet electric adjusting valve is communicated with the water outlet of the #3 low-pressure heater.
Furthermore, a slag cooler bypass pipeline is connected between the water inlet of the slag cooler water inlet electric adjusting valve and the water inlet of the low-pressure heater water inlet electric valve of the #2 low-pressure heater, and a slag cooler bypass electric adjusting valve is arranged on the slag cooler bypass pipeline.
Furthermore, a water outlet manual valve of the low-temperature economizer is arranged at a water outlet of the low-temperature economizer and is respectively connected with a water inlet electric valve at the side of the plate-changed condensed water and a water inlet electric valve of the plate-changed bypass; and the water inlet of the low-temperature economizer is provided with a low-temperature economizer water inlet manual valve and a low-temperature economizer water inlet electric valve, and the low-temperature economizer water inlet manual valve is respectively communicated with a slag cooler water outlet manual valve and a slag cooler water return-to-low-pressure-feed manual valve on a slag cooler water return-to-low-pressure-feed pipeline.
Further, the plate-replacing bypass water inlet electric valve is respectively communicated with a water inlet of the plate-replacing condensed water side water inlet electric valve and a water outlet of the plate-replacing condensed water side water outlet electric valve.
Furthermore, a low-saving return water to #1 low-pressure-adding manual valve and a low-saving return water to #1 low-pressure-adding electric valve are arranged on a pipeline between the water outlet of the plate-replacing bypass pipeline and the water inlet of the #1 low-pressure heater; and a low-saving water-to- #2 low-water-adding manual valve and a #2 low-water-adding manual main valve are sequentially arranged on the pipeline between the water outlet of the plate exchange bypass pipeline and the water inlet of the #2 low-pressure heater along the flow direction of condensed water, and the water inlet of the #2 low-water-adding manual main valve is simultaneously connected with the water outlet of a slag cooler water returning-to-low-water-adding manual regulating valve on the pipeline.
Furthermore, a water inlet and a water outlet of the #1 low-pressure heater, the #2 low-pressure heater and the #3 low-pressure heater are respectively provided with a low-pressure heater water inlet electric valve and a low-pressure heater water outlet electric valve.
Furthermore, a water inlet of the low-pressure heater water inlet electric valve and a water outlet of the low-pressure heater water outlet electric valve are respectively communicated with a low-pressure heater bypass pipeline, and the low-pressure heater bypass pipeline is provided with the low-pressure heater bypass electric valve.
According to the utility model discloses, following beneficial effect can be reached:
1. the slag cooler and the low-temperature economizer are arranged in series, and the condensed water can be used for recycling the heat of the slag cooler and the low-temperature economizer at the same time through once circulation and improving the temperature of the condensed water.
2. Through establishing ties plate heat exchanger in city heat supply network water circulation pipeline and low temperature economizer outlet pipe way, simultaneously because the board trades interior condensate side pressure and is higher than city heat supply network side pressure, the board trades the operation in-process, and the heat supply circulating water through the heat supply network side is difficult for leaking and leaks into the board and trades the condensate side, and condensate and city heat supply network circulating water direct contact do not, do not interfere each other, not only can guarantee the cleanliness factor of condensate quality of water, can also further guarantee the safe operation each other.
In urban heating seasons, the circulating water of the urban heat supply network is heated by adopting a high-temperature condensed water heat exchange mode, the low-temperature condensed water after heat exchange is led to a water inlet pipeline of the low-pressure heater so as to improve the temperature of the circulating water of the urban heat supply network, and meanwhile, the outlet water temperature is reduced due to the fact that the condensed water passes through the plate heat exchanger, and the requirement of the water inlet water temperature of the #2 low-pressure heater is met. When the urban heat supply needs to be operated at full load, the low-saving backwater to #1 low-pressure manual valve and the low-saving backwater to #1 low-pressure electric valve are closed, and the low-saving backwater to #2 low-pressure manual valve and the #2 low-pressure manual main water valve are opened, so that the cooled condensed water is introduced into the #2 low-pressure heater, the flow of the condensed water of the #2 low-pressure heater is increased, and the operation efficiency of the #2 low-pressure heater is improved; when the heat supply temperature needs to be adjusted in urban heat supply, the plate is opened again to change the bypass water inlet electric valve, and through adjusting the opening amount of the plate, part of high-temperature condensed water enters the plate through the plate and changes the bypass electric valve to reduce the through flow of the water inlet at the side where the plate is changed with the condensed water, and then the temperature of the circulating water of the heat supply network can be flexibly adjusted to adapt to the degree of the plate change investment, so that the requirement of the urban heat supply effect is met.
In non-heating seasons of cities, the flow direction of condensed water in a water outlet pipeline of the economizer can be quickly and conveniently switched by opening the plate-changing bypass water inlet electric valve, the low-saving return water to #1 low-adding manual valve and then closing the plate-type heat exchanger condensed water inlet side water inlet electric valve, the water outlet electric valve and the low-saving return water to #2 low-adding manual valve, so that the condensed water can timely exit the plate-type heat exchanger and then enter the plate-changing bypass, the stable operation of a system can be ensured, and the heat efficiency of a power station can be further improved.
3. The slag cooler backwater to low-pressure electric regulating valve is arranged on the slag cooler backwater to low-pressure electric regulating pipeline, the slag cooler backwater to low-pressure electric regulating valve is closed in urban heating seasons, and condensed water in the slag cooler water outlet pipeline directly enters the plate heat exchanger after being introduced into the low-temperature economizer, so that the heat exchange efficiency of the plate heat exchanger is ensured, the utilization rate of the heat of the condensed water is improved, and the economic benefit of the condensed water is further improved; in non-heat supply seasons of cities, the slag cooler is opened to return water to the low-voltage electric regulating valve, a certain opening degree is kept, and the running stability of the low-pressure heater and the low-temperature economizer can be ensured.
4. Because three groups of low-pressure heaters are arranged in series, and a manual valve and an electric valve are connected in series in a water inlet pipeline of the low-pressure heaters, condensed water after plate replacement or plate bypass replacement can be sent to the low-pressure heaters of different levels for graded heating, so that the temperature of the condensed water is improved, and the thermal efficiency of a power station is further improved.
5. Through setting up cold sediment ware bypass electric control valve, be convenient for when cold sediment ware or cold sediment ware supporting pipeline break down, can accurately switch and overhaul to guarantee the safe operation of whole unit.
Drawings
Fig. 1 is a structural view of the heat utilization system of the slag cooler and the low-temperature economizer of the circulating fluidized bed heat supply unit of the utility model.
In the figure, 1, a condensate water pipeline, 2, #3 low-pressure heaters, 3, #3 low-pressure heater water outlet pipeline, 4, a slag cooler bypass electric regulating valve, 5, a slag cooler water inlet electric regulating valve, 6, a slag cooler water inlet manual valve, 7, a flowmeter, 8, a slag cooler water outlet manual valve, 9, a low-temperature economizer water inlet manual valve, 10, a low-temperature economizer water inlet electric valve, 11, a slag cooler water return to low-pressure manual valve, 12, a slag cooler water return to low-pressure electric regulating valve, 13, a low-temperature economizer water outlet manual valve, 14, a plate-changing condensate water side water inlet electric valve, 15, a plate-changing condensate water side water outlet electric valve, 16, a plate-changing bypass water inlet electric valve, 17, a low-pressure return water to #1 low-pressure manual valve, 18, a low-pressure return water to #1 low-pressure electric valve, 19, a low-pressure return water to #2 low-pressure manual valve, 20, #2 low-pressure water inlet manual valve, 21, and a 2 low-pressure heater, 22. the system comprises an urban heat supply network circulation pipeline, 23 a low-saving backwater to #2 low water inlet pipeline, 24 a low-saving backwater to #1 low water inlet pipeline, 25, #1 low-pressure heaters, 26 a plate exchange bypass pipeline, 27 a plate heat exchange network side water inlet manual valve, 28 a plate heat exchange network side water outlet manual valve, 29 a low-temperature economizer, 30 a slag cooler, 31 a plate heat exchanger, 32 a slag cooler water outlet pipeline, 33 a low-temperature economizer water outlet pipeline, 34 a slag cooler backwater to a low water inlet pipeline.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the heat utilization system of the slag cooler and the low-temperature economizer of the circulating fluidized bed heating unit comprises a slag cooler 30, a low-temperature economizer 29, and #3 low-pressure heaters 2, #2 low-pressure heaters 21, and #1 low-pressure heaters 25 for heating condensed water step by step. The condensed water is heated by the #3 low-pressure heater 2 and then conveyed into the slag cooler 30 to cool the coal slag in the slag cooler, and the slag cooler 30 and the low-temperature economizer 29 are connected in series through the slag cooler water outlet pipeline 32, so that the condensed water can simultaneously recover the heat of the slag cooler 30 and the low-temperature economizer 29 through once circulation, the temperature of the condensed water is further increased, and the heat recovery efficiency is improved. In addition, the heat utilization system also comprises a plate heat exchanger 31 for exchanging heat of the circulating water of the urban heat supply network, the plate heat exchanger 31 is connected with the low-temperature economizer 29 in series through a low-temperature economizer water outlet pipeline 33, and condensed water passing through the slag cooler 30 and the low-temperature economizer 29 can be introduced into the condensed water side of the plate heat exchanger 31. The condensed water side water inlet end and the condensed water side water outlet end of the plate heat exchanger 31 are connected in parallel with a plate-changing bypass pipeline 26, a plate-changing condensed water side water inlet electric valve 14, a plate-changing condensed water side water outlet electric valve 15 and a plate-changing bypass water inlet electric valve 16 are respectively arranged on the condensed water side water inlet end, the condensed water side water outlet end and the plate-changing bypass pipeline 26 of the plate heat exchanger 31, the plate-changing bypass water inlet electric valve 16 is closed when the urban heat supply season is full of load and opened in the urban non-heat supply season, and the water outlet of the plate-changing bypass pipeline 26 is respectively communicated with the water inlet pipelines of the #1 low-pressure heater 25 and the #2 low-pressure heater 21.
More specifically, the plate heat exchanger 31 belongs to a surface heat exchanger, the pressure of the plate heat exchange condensate side is greater than the pressure of the urban heat supply network side, and the heat supply network side of the plate heat exchanger 31 is connected in series with the urban heat supply network circulation pipeline 22 through a plate heat exchange network side water inlet manual valve 27 and a plate heat exchange network side water outlet manual valve 28 respectively. And a water inlet and a water outlet of the #1 low-pressure heater 25, the #2 low-pressure heater 21 and the #3 low-pressure heater 2 are respectively provided with a low-pressure heater water inlet electric valve and a low-pressure heater water outlet electric valve, so that the condensed water can be controlled to smoothly flow into the low-pressure heater, and the heat efficiency of the low-pressure heater is ensured. The water inlet of the low-pressure heater water inlet electric valve and the water outlet of the low-pressure heater water outlet electric valve are respectively connected with a low-pressure heater bypass pipeline, and the low-pressure heater bypass pipeline is provided with a low-pressure heater bypass electric valve. The bypass electric valve of the low-pressure heater is in a normally closed state and is opened only when the low-pressure heater fails, so that the loop can be timely and accurately overhauled.
As shown in fig. 1, a manual slag cooler water outlet valve 8 is arranged at a water outlet of the slag cooler 30, the manual slag cooler water outlet valve 8 is respectively connected with a water inlet pipeline of the low-temperature economizer 29 and a slag cooler water return low-pressure pipeline 34, and during urban heating seasons, condensed water directly flows into the water inlet pipeline of the low-temperature economizer 29 through the manual slag cooler water outlet valve 8 and does not flow through the slag cooler water return low-pressure pipeline 34; in the non-heating season, the water flows from the water inlet pipeline of the low-temperature economizer 29 and the return water of the slag cooler to the low-pressure pipeline 34 at the same time. The slag cooler backwater to low-pressure feed pipeline 34 is provided with a slag cooler backwater to low-pressure feed manual valve 11 and a slag cooler backwater to low-pressure feed manual regulating valve 12. The slag cooler backwater to low-pressure manual valve 11 and the slag cooler backwater to low-pressure electric regulating valve 12 are both closed in urban heating seasons, the slag cooler backwater to low-pressure manual valve 11 is fully opened in urban non-heating seasons, and the slag cooler backwater to low-pressure electric regulating valve 12 keeps about 10% of opening degree. And the water inlet pipeline of the slag cooler 30 sequentially flows through the slag cooler water inlet electric adjusting valve 5, the slag cooler water inlet manual valve 6 and the flowmeter 7 along the direction of condensed water flow, and then enters the slag cooler. The water inlet of the slag cooler water inlet electric adjusting valve 5 is communicated with the water outlet of the #3 low-pressure heater 2, so that condensed water preheated by the #3 low-pressure heater 2 can flow into the slag cooler, and meanwhile, the opening degree of the slag cooler water inlet electric adjusting valve 5 can be adjusted to ensure that the whole unit can run stably. Be connected with cold sediment ware bypass pipeline between the water inlet of cold sediment ware intake electronic accent valve 5 and the water inlet of the low pressure heater intake electrically operated valve of #2 low pressure heater 21, be provided with cold sediment ware bypass electronic accent valve 4 on the cold sediment ware bypass pipeline, when cold sediment ware normal operating, cold sediment ware bypass electronic accent valve 4 is in normally closed state, only when cold sediment ware 30 or its supporting pipeline breaks down, cold sediment ware bypass electronic accent valve 4 just opens, the staff of being convenient for overhauls.
As shown in fig. 1, a low-temperature economizer water outlet manual valve 13 is arranged at a water outlet of a low-temperature economizer 29, and the low-temperature economizer water outlet manual valve 13 is respectively connected with a plate-changing condensed water side water inlet electric valve 14 and a plate-changing bypass water inlet electric valve 16; a low-temperature economizer water inlet manual valve 9 and a low-temperature economizer water inlet electric valve 10 are arranged at a water inlet of the low-temperature economizer 29, and the low-temperature economizer water inlet manual valve 9 is respectively connected with a slag cooler water outlet manual valve 8 and a slag cooler water return-to-low addition manual valve 11 on a slag cooler water return-to-low addition pipeline 34. In the urban heating season, after condensed water flows out of the water outlet electric valve 8 of the slag cooler, the water inlet manual valve 9 of the low-temperature economizer and the water inlet electric valve 10 of the low-temperature economizer are opened, and the condensed water can flow into the low-temperature economizer 29; in non-heating seasons of cities, after condensed water flows out of the water outlet electric valve 8 of the slag cooler, the water inlet manual valve 9 of the low-temperature economizer, the water inlet electric valve 10 of the low-temperature economizer and the slag cooler are opened to the low-heating manual valve 11, and the condensed water simultaneously flows into the low-temperature economizer 29 and the slag cooler to return water to the low-heating pipeline 34.
Preferably, the plate replacement bypass water inlet electric valve 16 is respectively communicated with the water inlet of the plate replacement condensed water side water inlet electric valve 14 and the water outlet of the plate replacement condensed water side water outlet electric valve 15. A low-saving return water to #1 low-pressure-adding manual valve 17 and a low-saving return water to #1 low-pressure-adding electric valve 18 are arranged on a pipeline between the water outlet of the plate-replacing bypass pipeline 26 and the water inlet of the #1 low-pressure heater 25; a low-saving return water to #2 low-adding manual valve 19 and a #2 low-adding water manual main valve 20 are sequentially arranged on a pipeline between the water outlet of the plate exchange bypass pipeline 26 and the water inlet of the #2 low-pressure heater 21 along the flow direction of condensed water, and the water inlet of the #2 low-adding water manual main valve 20 is simultaneously connected with the water outlet of the slag cooler return water to low-adding electric regulating valve 12 on a slag cooler return water to low-adding pipeline 34.
According to the operation requirement, the working principle is as follows:
the condensed water flows into the #3 low-pressure heater 2 through the condensed water pipeline 1, the #3 low-pressure heater 2 preheats the condensed water, and then the condensed water sequentially flows into the slag cooler 30 through the slag cooler water inlet electric adjusting valve 5, the slag cooler water inlet manual valve 6 and the flowmeter 7 to cool the coal slag in the slag cooler 30, and then the condensed water flows out into the slag cooler water outlet pipeline 32 through the slag cooler water outlet manual valve 8.
In the heating season, the temperature of low-saving outlet water after plate heat exchange meets the requirement of #2 low-adding inlet water temperature, the slag cooler backwater is closed to the low-adding manual valve 11, the plate heat exchange bypass electric valve 16, the low-temperature economizer backwater to the #1 low-adding manual valve 17 and the low-temperature economizer backwater to the #1 low-adding electric valve 18, condensed water only flows into the low-temperature economizer 29 through the low-temperature economizer inlet water manual valve 9 and the low-temperature economizer inlet electric valve 10 to cool high-temperature flue gas, and the condensed water after twice waste heat recovery flows into the plate heat exchanger 31 through the low-temperature economizer outlet water manual valve 13, the plate heat exchange condensed water side inlet electric valve 14 and the plate heat exchange condensed water side outlet electric valve 15, so that the condensed water flows into the plate heat exchanger 31 to exchange heat with the hot-network circulating water. Meanwhile, as the plate heat exchanger 31 belongs to a surface heat exchanger, and the pressure of the plate exchange condensate side is greater than that of the urban heat supply network side, in the normal operation process of the plate heat exchanger, the heat supply network circulating water is not easy to leak and enters the plate exchange condensate side, so that the condensate and the urban heat supply network circulating water are not in direct contact and do not interfere with each other, and the safe operation between the condensate and the urban heat supply network circulating water can be ensured.
The condensed water after heat exchange enters a plate exchange bypass 26 through a plate exchange condensed water side water outlet electric valve 15, then enters a #2 low-pressure heater 21 for heating after passing through a low-saving return water to a #2 low-pressure water adding manual valve 19 and a #2 low-pressure water adding manual main valve 20, then enters a #1 low-pressure heater 25 for heating, and finally, the heated condensed water flows into the next process of the steam turbine system.
When the heating temperature needs to be adjusted to city heat supply network circulating water, open the board and trade bypass intake motorised valve 16, through adjusting its aperture volume, during some high temperature condensate traded bypass motorised valve 16 and got into board and traded bypass pipeline 26 through the board to reduce the board and trade the through flow that the condensate side was intake, and then can adjust the temperature of heat supply network circulating water in a flexible way, trade the degree that drops into with the adaptation board, thereby satisfy the requirement of city heating effect.
According to the calculation of urban heat supply season of 2019 and 2020 year, when the unit runs at 85% rated load, the temperature of condensed water in a #3 low-pressure heater water outlet pipeline is about 55 ℃, the temperature of condensed water on the side of a plate heat exchanger and the temperature of return water on the side of the plate heat exchanger are about 81 ℃ and 55 ℃, and the flow rate is 322 t/h; the return water temperature of the circulating water side of the urban heat network of the plate heat exchanger is 47 ℃ and 72 ℃, the flow rate is 304t/h, the heat efficiency is nearly 91% through calculation, and the annual income is nearly 130 ten thousand yuan.
In non-heating seasons of cities, the outlet water temperature of the low province meets the inlet water temperature requirement of the #1 low-pressure heater, the slag cooler backwater to low-pressure water adding manual valve 11, the plate-changing bypass water inlet electric valve 16, the low-pressure water returning to the #1 low-pressure water adding manual valve 17 and the low-pressure water returning to the #1 low-pressure electric valve 18 are opened, the plate-changing condensate side water inlet electric valve 14, the plate-changing condensate side water outlet electric valve 15 and the low-pressure water returning to the #2 low-pressure water adding manual valve 19 are closed, meanwhile, the slag cooler backwater to the low-pressure electric regulating valve 12 keeps about 10% of opening, and at least part of condensate returns to the low-pressure water adding pipeline 34 through the slag cooler backwater to flow into the #2 low-pressure water adding main valve 20 and then flows into the #2 low; most of the condensed water flows into the low-temperature economizer 29, flows into the plate-change bypass pipe 26 through the plate-change bypass electric valve 16, flows into the #1 low-pressure heater 25 through the #1 low-pressure manual valve 17 for low-level return water and the #1 low-pressure electric valve 18 for low-level return water, is heated, and finally flows into the next process of the steam turbine system.
In the normal operation process, cold sediment ware bypass electricity transfers valve 4 and low pressure feed water heater bypass motorised valve all is in the closed condition, and when the pipeline broke down, cold sediment ware bypass electricity transfers valve 4 and low pressure feed water heater bypass motorised valve just opens to guarantee can timely effectual maintenance of pipeline.
It should be noted that the above embodiments are only used for illustrating the present invention, but the present invention is not limited to the above embodiments, and any simple modification, equivalent change and modification made to the above embodiments by the technical spirit of the present invention all fall into the protection scope of the present invention.