阅读说明：本技术 一种构型自适应灵活清洁协同燃煤发电系统及运行方法 (Configuration self-adaptive flexible clean cooperative coal-fired power generation system and operation method ) 是由 刘明 严俊杰 刘继平 种道彤 邢秦安 于 2020-05-24 设计创作，主要内容包括：本发明公开了一种构型自适应灵活清洁协同燃煤发电系统及运行方法,该系统省煤器布置有给水调节阀组,通过给水调节阀组可以实现烟气、工质间换热流程的调整,可以根据负荷进行构型的自适应调整,改变烟气、工质间的换热流向,从而调节SCR脱硝装置的入口温度,实现SCR脱硝装置的全工况高效运行。本发明系统投资低,采用本发明的系统锅炉效率高、运行灵活性高。(The invention discloses a configuration self-adaptive flexible clean cooperative coal-fired power generation system and an operation method thereof.A coal economizer of the system is provided with a water supply regulating valve group, the adjustment of a heat exchange flow between flue gas and a working medium can be realized through the water supply regulating valve group, the configuration self-adaptive regulation can be carried out according to load, and the heat exchange flow direction between the flue gas and the working medium is changed, so that the inlet temperature of an SCR (selective catalytic reduction) denitration device is regulated, and the full-working-condition efficient operation of the SCR denitration device is realized. The system has low investment, and the boiler adopting the system has high efficiency and high operation flexibility.)

1. A configuration self-adaptive flexible clean cooperative coal-fired power generation system is characterized in that: the device comprises an economizer (2) and an SCR denitration device (4) which are sequentially arranged in a flue of a boiler (1) along the flow direction of flue gas; the lower port of the economizer (2) is connected with a boiler water supply inlet through a second water supply regulating valve (32) and a first water supply regulating valve (31) by a pipeline, and the second water supply regulating valve (32) and the first water supply regulating valve (31) are connected with a water wall water supply inlet through a fifth water supply regulating valve (35) by a pipeline; the upper port of the economizer (2) is connected with a water cooling wall water supply inlet through a third water supply regulating valve (33) by a pipeline, and the upper port of the economizer (2) is connected with a boiler water supply inlet through a fourth water supply regulating valve (34) and a sixth water supply regulating valve (36) by pipelines; the boiler feed water inlet is also connected with the water wall feed water inlet through a seventh feed water regulating valve (37) by a pipeline.

2. A configuration adaptive flexible clean collaborative coal fired power generation system according to claim 1, wherein: and the boiler feed water inlet is communicated with the outlet of the first-stage regenerative heater with the highest pressure of the turbine regenerative system.

3. A configuration adaptive flexible clean collaborative coal fired power generation system according to claim 1, wherein: the first water supply regulating valve (31) to the seventh water supply regulating valve (37) are automatic regulating valves.

4. The method of claim 1, wherein the method comprises: through adjusting the regulating valve group of a water supply regulating valve (31) to a water supply regulating valve (37), the downstream and upstream relations of flue gas and water supply in the economizer (2) are changed, so that the inlet flue gas temperature of the SCR denitration device (4) is adjusted to meet the requirement of the working temperature interval of the SCR denitration device (4), and the specific adjusting method is as follows:

1) if the measured temperature of the flue gas at the inlet of the SCR denitration device (4) is higher than the highest working temperature of the SCR denitration device, firstly closing a seventh water supply regulating valve (37), if the temperature of the flue gas at the inlet of the SCR denitration device (4) is still higher than the highest working temperature of the SCR denitration device, closing a fourth water supply regulating valve (34), a fifth water supply regulating valve (35) and a sixth water supply regulating valve (36), opening a first water supply regulating valve (31), a second water supply regulating valve (32) and a third water supply regulating valve (33), enabling boiler feed water to enter the economizer (2) from the lower port of the economizer (2) and then flow out from the upper port of the economizer (2) to enter a water-cooled wall, and at the moment, the flue gas in the economizer (2) and the feed water;

2) if the temperature of flue gas at the inlet of the SCR denitration device (4) is measured to be lower than the highest working temperature, gradually opening a fourth water supply regulating valve (34), a fifth water supply regulating valve (35) and a sixth water supply regulating valve (36), and gradually closing a first water supply regulating valve (31) and a third water supply regulating valve (33), so that boiler feed water enters the economizer (2) from the upper port of the economizer (2) and then flows out from the lower port of the economizer (2) to enter a water-cooled wall, and at the moment, the flue gas in the economizer (2) and the feed water are in a forward flow relation; if the inlet flue gas temperature of the SCR denitration device (4) is still lower than the lowest working temperature, the No. seven water supply regulating valve (37) is gradually opened, so that the water supply directly enters the water-cooled wall through a bypass.

5. The method of claim 4, wherein the method comprises: the working temperature range of the SCR denitration device (4) is 300-400 ℃.

6. The method of claim 4, wherein the method comprises: when adjusting the regulating valve group of the first water supply regulating valve (31) to the seventh water supply regulating valve (37), attention is paid to the linkage of the switch of the water supply regulating valve, so that the stability of water pressure is maintained.

Technical Field

The invention belongs to the field of coal-fired power generation, and particularly relates to a configuration self-adaptive flexible clean cooperative coal-fired power generation system and an operation method.

Background

The construction of a clean, low-carbon, safe and efficient energy system is the development direction of energy structure transformation in China. Therefore, in recent years, the scale installed capacity of renewable energy in China is rapidly developed, and the utilization efficiency of conventional fossil energy is gradually improved. However, the time-varying characteristics of wind power and solar power generation are strong, and the operation safety of a power grid is threatened. For this reason, it is highly desirable to improve the operational flexibility of conventional coal-fired power generating units, i.e., to improve the variable load interval and variable load rate of the coal-fired power generating units. Therefore, coal-fired power generating units present new features of operation that frequently vary in depth and load.

However, when the train is operated at a low load, the denitration efficiency of the coal-fired train is significantly reduced. The main reason is that the SCR denitration catalyst has a proper working temperature interval, but when the unit is in load reduction operation, the temperature of the flue gas at the inlet of the SCR is reduced, so that the SCR denitration device is difficult to operate in the proper operating temperature interval, and the denitration efficiency is reduced. The existing method for improving the flue gas temperature at the SCR inlet mainly comprises a flue gas bypass, a coal economizer grading arrangement, a water supply bypass and the like. But the work load of the flue gas bypass technology is large, and the boiler efficiency is obviously reduced; the coal economizer is arranged and modified in a grading manner, so that the workload is large; the flue gas temperature regulation performance of the water supply bypass technology is limited, and the operation safety of the economizer is not easy to guarantee.

How to improve the full-working-condition operation performance of the coal-fired power station, improve the operation flexibility and the operation efficiency of the coal-fired power station and reduce the pollutant emission is an urgent need of the coal-fired power generation technology.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to provide a configuration self-adaptive flexible clean cooperative coal-fired power generation system and an operation method thereof. The system has low investment, and the boiler adopting the system has high efficiency and high operation flexibility.

In order to achieve the purpose, the invention adopts the following technical scheme:

a configuration self-adaptive flexible clean cooperative coal-fired power generation system comprises a coal economizer 2 and an SCR denitration device 4 which are sequentially arranged in a flue of a boiler 1 along the flow direction of flue gas; the lower port of the economizer 2 is connected with a boiler water supply inlet through a second water supply regulating valve 32 and a first water supply regulating valve 31 by pipelines, and the second water supply regulating valve 32 and the first water supply regulating valve 31 are connected with a water wall water supply inlet through a fifth water supply regulating valve 35 by pipelines; the upper port of the economizer 2 is connected with a water-cooled wall feed water inlet through a third feed water regulating valve 33 by a pipeline, and the upper port of the economizer 2 is connected with a boiler feed water inlet through a fourth feed water regulating valve 34 and a sixth feed water regulating valve 36 by pipelines; the boiler feed water inlet is also connected with the water wall feed water inlet through a seventh feed water regulating valve 37 by a pipeline.

And the boiler feed water inlet is communicated with the outlet of the first-stage regenerative heater with the highest pressure of the turbine regenerative system.

The first water supply regulating valve 31 to the seventh water supply regulating valve 37 are automatic regulating valves.

According to the operation method of the configuration self-adaptive flexible cleaning cooperative coal-fired power generation system, the downstream and upstream relations between the flue gas and the feed water in the economizer 2 are changed by adjusting the regulating valve groups of the first water supply regulating valve 31 to the seventh water supply regulating valve 37, so that the inlet flue gas temperature of the SCR denitration device 4 is regulated to meet the requirement of the SCR denitration device 4 on the working temperature interval, and the specific regulating method is that the inlet flue gas temperature of the SCR denitration device 4 is measured:

1) if the temperature of the flue gas at the inlet of the SCR denitration device 4 is measured to be higher than the highest working temperature, firstly closing the seventh water supply regulating valve 37, if the temperature of the flue gas at the inlet of the SCR denitration device 4 is still higher than the highest working temperature, closing the fourth water supply regulating valve 34, the fifth water supply regulating valve 35 and the sixth water supply regulating valve 36, opening the first water supply regulating valve 31, the second water supply regulating valve 32 and the third water supply regulating valve 33, enabling the boiler feed water to enter the economizer 2 from the lower port of the economizer 2 and then flow out from the upper port of the economizer 2 to enter a water cooling wall, and enabling the flue gas in the economizer 2 and the feed water to be in a countercurrent relationship at the moment;

2) if the temperature of the flue gas at the inlet of the SCR denitration device 4 is measured to be lower than the highest working temperature, gradually opening a fourth water supply regulating valve 34, a fifth water supply regulating valve 35 and a sixth water supply regulating valve 36, and gradually closing a first water supply regulating valve 31 and a third water supply regulating valve 33, so that the boiler feed water enters the economizer 2 from the upper port of the economizer 2 and then flows out from the lower port of the economizer 2 to enter a water cooling wall, and at the moment, the flue gas in the economizer 2 and the feed water are in a forward flow relationship; if the temperature of the flue gas at the inlet of the SCR denitration device 4 is still lower than the lowest working temperature, the No. seven water supply regulating valve 37 is gradually opened, so that the feed water directly enters the water-cooled wall through a bypass.

The working temperature range of the SCR denitration device 4 is 300-400 ℃.

When adjusting the regulating valve group of the first water supply regulating valve 31 to the seventh water supply regulating valve 37, attention is paid to the linkage of the opening and closing of the water supply regulating valves, so that the stability of the water pressure is maintained.

The system can realize self-adjustment and self-adaptation of the configuration when the unit operates at different loads, and the operation method can maintain the temperature operation range of the denitration device and ensure the operation safety of the economizer. The invention can be adopted when the operation flexibility of the coal-fired unit which frequently operates with variable load is improved and the denitration efficiency is improved.

Compared with the prior art, the invention has the following advantages:

(1) the invention can enlarge the denitration operation interval of the SCR system and realize high-efficiency denitration under all working conditions;

(2) the invention has low modification cost, and can obviously reduce the modification cost of SCR full-working-condition denitration;

(3) the invention can reduce the temperature of the working medium at the outlet of the economizer in the adjusting process and ensure the operation safety of the economizer.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention.

FIG. 2 is a comparative graph of SCR inlet flue gas temperature for a coal-fired power generating unit.

FIG. 3 is a temperature comparison chart of the working medium at the outlet of the economizer of the present invention for a case of a coal-fired power generating set.

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 configuration self-adaptive flexible clean cooperative coal-fired power generation system comprises an economizer 2 and an SCR denitration device 4 which are sequentially arranged in a flue of a boiler 1 along a flue gas flow direction; the lower port of the economizer 2 is connected with a boiler water supply inlet through a second water supply regulating valve 32 and a first water supply regulating valve 31 by pipelines, and the second water supply regulating valve 32 and the first water supply regulating valve 31 are connected with a water wall water supply inlet through a fifth water supply regulating valve 35 by pipelines; the upper port of the economizer 2 is connected with a water-cooled wall feed water inlet through a third feed water regulating valve 33 by a pipeline, and the upper port of the economizer 2 is connected with a boiler feed water inlet through a fourth feed water regulating valve 34 and a sixth feed water regulating valve 36 by pipelines; the boiler feed water inlet is also connected with the water wall feed water inlet through a seventh feed water regulating valve 37 by a pipeline.

As a preferred embodiment of the invention, the boiler feed water inlet is communicated with the outlet of the primary regenerative heater with the highest pressure of the turbine regenerative system, so that the temperature of the boiler feed water inlet can be maintained in a proper temperature range.

As a preferred embodiment of the present invention, the first to seventh water supply regulating valves 31 to 37 are automatic regulating valves, which can improve the regulating performance of the system.

The operation method of the configuration self-adaptive flexible cleaning cooperative coal-fired power generation system changes the downstream and upstream relations of flue gas and feed water in the economizer 2 by adjusting the regulating valve groups from the first water supply regulating valve 31 to the seventh water supply regulating valve 37, so that the inlet flue gas temperature of the SCR denitration device 4 is regulated to meet the requirement of the working temperature interval of the SCR denitration device 4, and the specific regulating method is that the inlet flue gas temperature of the SCR denitration device 4 is measured:

1) if the temperature of the flue gas at the inlet of the SCR denitration device 4 is measured to be higher than the highest working temperature, firstly closing the seventh water supply regulating valve 37, if the temperature of the flue gas at the inlet of the SCR denitration device 4 is still higher than the highest working temperature, closing the fourth water supply regulating valve 34, the fifth water supply regulating valve 35 and the sixth water supply regulating valve 36, opening the first water supply regulating valve 31, the second water supply regulating valve 32 and the third water supply regulating valve 33, enabling the boiler feed water to enter the economizer 2 from the lower port of the economizer 2 and then flow out from the upper port of the economizer 2 to enter a water cooling wall, and enabling the flue gas in the economizer 2 and the feed water to be in a countercurrent relationship at the moment;

2) if the temperature of the flue gas at the inlet of the SCR denitration device 4 is measured to be lower than the highest working temperature, gradually opening a fourth water supply regulating valve 34, a fifth water supply regulating valve 35 and a sixth water supply regulating valve 36, and gradually closing a first water supply regulating valve 31 and a third water supply regulating valve 33, so that the boiler feed water enters the economizer 2 from the upper port of the economizer 2 and then flows out from the lower port of the economizer 2 to enter a water cooling wall, and at the moment, the flue gas in the economizer 2 and the feed water are in a forward flow relationship; if the temperature of the flue gas at the inlet of the SCR denitration device 4 is still lower than the lowest working temperature, the No. seven water supply regulating valve 37 is gradually opened, so that the feed water directly enters the water-cooled wall through a bypass.

The working temperature range of the SCR denitration device 4 is 300-400 ℃.

In a preferred embodiment of the present invention, when adjusting the set of the first to seventh feed adjusting valves 31 to 37, the stability of the water pressure is maintained by paying attention to the linkage of the opening and closing of the feed adjusting valves.

The system can switch the system configuration when the unit operates in different intervals, so that the temperature of the flue gas at the SCR inlet is maintained in the active operation interval of the SCR denitration catalyst. As shown in FIG. 2, when the load factor of the coal-fired power generation system is below 0.5, the system and the operation method of the invention are adopted to maintain the flue gas temperature at the SCR inlet above 300 ℃. Compared with the conventional flue gas bypass and low-temperature economizer which are arranged in a grading manner, the invention has low modification cost. As shown in figure 3, compared with the conventional water supply bypass system, the temperature of the working medium at the outlet of the economizer is low, the operation safety of the economizer can be ensured, and the temperature of the working medium at the outlet of the economizer can be reduced by 12 ℃ when the load factor of a case unit is 0.3.