阅读说明：本技术 一种脱硫浆液闪蒸回收烟气余热和水分的系统及方法 (System and method for recovering flue gas waste heat and moisture by desulfurization slurry flash evaporation ) 是由 彭烁 周贤 宋润 王绍民 钟迪 王保民 于 2020-04-29 设计创作，主要内容包括：本发明提供的一种脱硫浆液闪蒸回收烟气余热和水分的系统及方法,包括汽轮机、凝汽器、混合器、给水加热器、脱硫塔、闪蒸罐和气液混合器,其中,汽轮机上设置有过热蒸汽入口和排汽出口,所述排汽出口连接有凝汽器的蒸汽入口,所述汽轮机上的抽汽出口连接给水加热器的抽汽入口；所述凝汽器上的凝结水出口连接混合器的凝结水入口,所述混合器的凝结水出口连接给水加热器的给水入口；所述脱硫塔上设置有脱硫浆液入口和烟气入口,所述脱硫浆液入口连接有闪蒸罐的浆液出口；所述脱硫塔上的浆液出口连接闪蒸罐的浆液入口；所述闪蒸罐上的蒸汽出口连接气液混合器上的蒸汽入口；所述气液混合器上的补水出口连接混合器的补水入口。(The system and the method for recovering flue gas waste heat and moisture by flash evaporation of desulfurization slurry comprise a steam turbine, a condenser, a mixer, a feed water heater, a desulfurization tower, a flash tank and a gas-liquid mixer, wherein the steam turbine is provided with a superheated steam inlet and a steam exhaust outlet, the steam exhaust outlet is connected with a steam inlet of the condenser, and a steam extraction outlet on the steam turbine is connected with a steam extraction inlet of the feed water heater; a condensed water outlet on the condenser is connected with a condensed water inlet of the mixer, and a condensed water outlet of the mixer is connected with a feed water inlet of the feed water heater; the desulfurization tower is provided with a desulfurization slurry inlet and a flue gas inlet, and the desulfurization slurry inlet is connected with a slurry outlet of the flash tank; a slurry outlet on the desulfurizing tower is connected with a slurry inlet of the flash tank; a steam outlet on the flash tank is connected with a steam inlet on a gas-liquid mixer; and a water supplementing outlet on the gas-liquid mixer is connected with a water supplementing inlet of the mixer.)

1. The system for recovering flue gas waste heat and moisture by virtue of flash evaporation of desulfurization slurry is characterized by comprising a steam turbine (1), a condenser (2), a mixer (4), a feed water heater (5), a desulfurization tower (6), a flash tank 8() and a gas-liquid mixer (11), wherein the steam turbine (1) is provided with an overheated steam inlet and an exhaust steam outlet, the exhaust steam outlet is connected with a steam inlet of the condenser (2), and an exhaust steam outlet on the steam turbine (1) is connected with an exhaust steam inlet of the feed water heater (5); a condensed water outlet on the condenser (2) is connected with a condensed water inlet of a mixer (4), and a condensed water outlet of the mixer (4) is connected with a feed water inlet of a feed water heater (5); a desulfurization slurry inlet and a flue gas inlet are arranged on the desulfurization tower (6), and the desulfurization slurry inlet is connected with a slurry outlet of the flash tank (8); a slurry outlet on the desulfurizing tower (6) is connected with a slurry inlet of the flash tank (8); a steam outlet on the flash tank (8) is connected with a steam inlet on a gas-liquid mixer (11); and a water supplementing outlet on the gas-liquid mixer (11) is connected with a water supplementing inlet of the mixer (4).

2. The system for recovering the flue gas waste heat and the moisture by the flash evaporation of the desulfurization slurry as claimed in claim 1, wherein a condensed water outlet on the condenser (2) is connected with a condensed water inlet of the mixer (4) through a circulating pump (3).

3. The system for recovering the flue gas waste heat and the moisture by the flash evaporation of the desulfurization slurry as claimed in claim 1, wherein the feed water heater (5) is provided with a hydrophobic outlet and a steam outlet, and the steam outlet is connected with a thermodynamic system.

4. The system for recovering the waste heat and the moisture of the flue gas by the flash evaporation of the desulfurization slurry as claimed in claim 1, wherein the desulfurization slurry inlet on the desulfurization tower (6) is arranged above the flue gas inlet; the flue gas inlet is connected with a draught fan.

5. The system for recovering the waste heat and the moisture in the flue gas by the flash evaporation of the desulfurization slurry as claimed in claim 1, wherein a slurry outlet on the desulfurization tower (6) is connected with a slurry inlet of the flash evaporation tank (8) through a slurry pump (7).

6. The system for recovering the flue gas waste heat and the moisture by the flash evaporation of the desulfurization slurry as claimed in claim 1, wherein a water replenishing inlet is arranged on the gas-liquid mixer (11).

7. The system for recovering the flue gas waste heat and the moisture by the flash evaporation of the desulfurization slurry as claimed in claim 1, wherein the water supplementing outlet of the gas-liquid mixer (11) is connected with the water supplementing inlet of the mixer (4) through a pressure pump (9).

8. The system for recovering the waste heat and the moisture of the flue gas by the flash evaporation of the desulfurization slurry as claimed in claim 1, wherein a flue gas outlet arranged on the desulfurization tower (6) is connected with a chimney (10).

9. The method for recovering the waste heat and the moisture of the flue gas by the flash evaporation of the desulfurization slurry is characterized in that the system for recovering the waste heat and the moisture of the flue gas by the flash evaporation of the desulfurization slurry based on any one of claims 1 to 8 comprises the following steps:

the flue gas and the desulfurization slurry sprayed from the top of the flue gas in the desulfurization tower (6) have desulfurization reaction, and simultaneously, the temperature is reduced and the humidity is increased; the desulfurization slurry at the bottom of the desulfurization tower (6) is fed into a flash tank (8), the desulfurization slurry in the flash tank (8) is cooled through an evaporative cooling process to become cold slurry, and the cold slurry is fed into the desulfurization tower (6) and sprayed into the tower from the top;

after the superheated steam enters the steam turbine (1), a rotor of the steam turbine (1) is pushed to rotate to do work, the steam which does work is discharged from a steam outlet of the steam turbine (1), is cooled by cooling water in the condenser (2) and is condensed into water, and after the steam enters the mixer (4 () to be mixed with water supplement discharged from the gas-liquid mixer (11), the mixed water enters the water supply heater (5) to be heated by the backheating steam extraction of the steam turbine (1).

Technical Field

The invention belongs to the field of energy conservation and water conservation of coal-fired power stations, and particularly relates to a system and a method for recovering flue gas waste heat and moisture by flash evaporation of desulfurization slurry.

Background

In the primary energy which has been proved in China, coal occupies nearly 90 percent, and according to the latest statistics, the total installed capacity of coal and electricity reaches about 11.9 hundred million kilowatts in 2019. Coal power provides important power guarantee for national economic development and people's life in China, however, smoke and SO generated by coal power₂、NO_xHeavy metal pollutants such as mercury and a large amount of carbon dioxide greenhouse gas cause serious environmental problems. The energy-saving and emission-reducing technology is a long-term development strategy in China for coordinating the contradiction between the environment and the power development, promoting the high efficiency of the coal-electricity industry and developing the energy-saving and emission-reducing technology.

The utility boiler, as the first large energy consumption equipment in China, consumes about 15 million tons of standard coal each year, accounting for nearly 50% of the total coal consumption in China. At present, the thermal efficiency of large-scale power station boilers is generally about 90-94%, and the heat loss of exhaust smoke accounts for more than half of the total heat loss, so that huge waste heat resources are stored. And a large amount of moisture contained in the boiler exhaust gas is discharged to the atmosphere. If the waste heat of the boiler flue gas can be deeply utilized, the thermal power generating unit can save a large amount of coal consumption, thereby reducing pollutant emission and saving water, and having great significance to the strategy of energy conservation and emission reduction in China.

Disclosure of Invention

The invention aims to provide a system and a method for recovering flue gas waste heat and moisture by desulfurization slurry flash evaporation, which solve the problems that waste heat resources of a power station boiler in the prior art are wasted and environmental pollution is caused.

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

the invention provides a system for recovering flue gas waste heat and moisture by flash evaporation of desulfurization slurry, which comprises a steam turbine, a condenser, a mixer, a feed water heater, a desulfurization tower, a flash tank and a gas-liquid mixer, wherein the steam turbine is provided with a superheated steam inlet and a steam exhaust outlet, the steam exhaust outlet is connected with a steam inlet of the condenser, and a steam extraction outlet on the steam turbine is connected with a steam extraction inlet of the feed water heater; a condensed water outlet on the condenser is connected with a condensed water inlet of the mixer, and a condensed water outlet of the mixer is connected with a feed water inlet of the feed water heater; the desulfurization tower is provided with a desulfurization slurry inlet and a flue gas inlet, and the desulfurization slurry inlet is connected with a slurry outlet of the flash tank; a slurry outlet on the desulfurizing tower is connected with a slurry inlet of the flash tank; a steam outlet on the flash tank is connected with a steam inlet on a gas-liquid mixer; and a water supplementing outlet on the gas-liquid mixer is connected with a water supplementing inlet of the mixer.

Preferably, a condensed water outlet on the condenser is connected with a condensed water inlet of the mixer through a circulating pump.

Preferably, the feed water heater is provided with a drainage outlet and a steam outlet, and the steam outlet is connected with a thermodynamic system.

Preferably, the desulfurization slurry inlet on the desulfurization tower is arranged above the flue gas inlet; the flue gas inlet is connected with a draught fan.

Preferably, the slurry outlet on the desulfurization tower is connected with the slurry inlet of the flash tank through a slurry pump.

Preferably, a water replenishing inlet is arranged on the gas-liquid mixer.

Preferably, the water replenishing outlet of the gas-liquid mixer is connected with the water replenishing inlet of the mixer through a pressure pump.

Preferably, a flue gas outlet arranged on the desulfurizing tower is connected with a chimney.

A method for recovering flue gas waste heat and moisture by desulfurization slurry flash evaporation is based on a system for recovering flue gas waste heat and moisture by desulfurization slurry flash evaporation, and comprises the following steps:

the flue gas and the desulfurization slurry sprayed from the top of the flue gas in the desulfurization tower have desulfurization reaction, and simultaneously, the temperature is reduced and the humidity is increased; feeding the desulfurization slurry at the bottom of the desulfurization tower into a flash tank, cooling the desulfurization slurry in the flash tank into cold slurry through an evaporative cooling process, feeding the cold slurry into the desulfurization tower, and spraying the cold slurry into the tower from the top;

after the superheated steam enters the steam turbine, a rotor of the steam turbine is pushed to rotate to do work, the steam after doing work is discharged from a steam outlet of the steam turbine, is cooled by cooling water in a condenser, is condensed into water, enters a mixer to be mixed with water supplement discharged from a gas-liquid mixer, and then enters a water supply heater to be heated by backheating steam extraction of the steam turbine.

Compared with the prior art, the invention has the beneficial effects that:

according to the system and the method for recovering the flue gas waste heat and the moisture by the flash evaporation of the desulfurization slurry, the steam flashed by the flash evaporation tank carries sensible heat and latent heat of the flue gas, is mixed with the supplemented water and then is conveyed to a thermodynamic system, so that the heat of the desulfurization slurry in the wet desulfurization tower can be recovered, the aim of deeply recovering the flue gas waste heat after desulfurization is indirectly fulfilled, the energy utilization efficiency is improved, and the obvious economic benefit is achieved; a large amount of water vapor is extracted from the desulfurization slurry through a flash tank, and the water vapor is condensed in an absorption heat pump and then is mixed with the demineralized water replenishing water of the power plant and then is conveyed to a thermodynamic system, so that the water consumption of the power plant is reduced; after the desulfurization slurry is subjected to flash evaporation, the evaporative cooling of the desulfurization slurry is realized, the temperature and the water content of the flue gas leaving the desulfurization tower can be greatly reduced after the cold slurry is sprayed on the flue gas, and the aim of eliminating white smoke plume is fulfilled.

Drawings

Fig. 1 is a schematic view of the structure according to the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1, the system for recovering flue gas waste heat and moisture by flash evaporation of desulfurization slurry provided by the invention comprises a steam turbine 1, a condenser 2, a circulating pump 3, a mixer 4, a feed water heater 5, a desulfurization tower 6, a slurry pump 7, a flash tank 8, a booster pump 9, a chimney 10 and a gas-liquid mixer 11, wherein a steam exhaust outlet on the steam turbine 1 is connected with a steam inlet of the condenser 2, and a condensed water outlet on the condenser 2 is connected with a condensed water inlet of the mixer 4 through the circulating pump 3; the condensed water outlet of the mixer 4 is connected with the feed water inlet of the feed water heater 5.

The steam turbine 1 is provided with a superheated steam inlet and a steam extraction outlet.

The steam extraction outlet is connected with a steam extraction inlet on the water supply heater 5.

And a steam outlet is arranged on the feed water heater 5 and is connected with a deaerator.

The feed water heater 5 is provided with a drainage outlet.

And a flue gas inlet and a desulfurization slurry inlet are formed in the desulfurization tower 6, wherein the desulfurization slurry inlet is connected with a slurry outlet of the flash tank 8.

The desulfurization slurry inlet is arranged above the flue gas inlet.

And a slurry outlet on the desulfurizing tower 6 is connected with a slurry inlet of the flash tank 8 through a slurry pump 7.

A steam outlet on the flash tank 8 is connected with a steam inlet on a gas-liquid mixer 11.

And a water supplementing inlet and a water supplementing outlet are arranged on the gas-liquid mixer 11.

And a water supplementing outlet of the gas-liquid mixer 11 is connected with a water supplementing inlet of the mixer 4 through a pressure pump 9.

And a flue gas outlet arranged on the desulfurizing tower 6 is connected with a chimney 10.

The working process is as follows:

the flue gas from the induced draft fan and the desulfurization slurry sprayed from the top of the induced draft fan are subjected to desulfurization reaction in the desulfurization tower 6, and simultaneously, the temperature is reduced and the humidity is increased; the desulfurization slurry at the bottom of the desulfurization tower 6 is sent into a flash tank 8 through a slurry pump 7, the desulfurization slurry in the flash tank 8 is subjected to an evaporative cooling process to flash steam, and is cooled to become cold slurry which is sent into the desulfurization tower 6 and sprayed into the tower from the top; the flue gas leaves the desulfurizing tower 6 after spraying and desulfurizing reaction, and is sent into a chimney 10 to be discharged into the atmosphere.

Superheated steam enters the steam turbine 1, the rotor of the steam turbine 1 is pushed to rotate to do work, the steam after doing work is discharged from the steam outlet of the steam turbine 1, is cooled by cooling water in the condenser 2, is condensed into water, is boosted by the circulating pump 3, enters the mixer 4 and is mixed with water supplement coming out of the pressure pump 9, enters the feed water heater 5 and is heated by the backheating steam extraction of the steam turbine 1, and then is sent to the deaerator.

The invention has the beneficial effects that:

1. the steam carries latent heat and sensible heat and carries thermodynamic system after power plant's demineralized water moisturizing mixes, can retrieve the heat of the interior desulfurization thick liquid of wet flue gas desulfurization tower, indirectly reaches the purpose of the flue gas waste heat after the degree of depth recovery desulfurization, improves energy efficiency, has apparent economic benefits.

2. A large amount of water vapor is extracted from the desulfurization slurry by a flash evaporation method, and the water vapor is mixed with the supplemented water of the power plant desalted water and then is conveyed to a thermodynamic system, so that the water consumption of the power plant is reduced.

3. After a large amount of water vapor is extracted from the desulfurization slurry by a flash evaporation method, the problem of water balance in the desulfurization tower is solved, and equipment failure caused by pool expansion of the desulfurization tower is avoided.

4. After the desulfurization slurry is subjected to flash evaporation, the evaporative cooling of the desulfurization slurry is realized, the temperature and the water content of the flue gas leaving the desulfurization tower can be greatly reduced after the cold slurry is sprayed on the flue gas, and the aim of eliminating white smoke plume is fulfilled.