阅读说明：本技术 一种烟气余热和水分回收协同消白烟装置的工作方法 (Working method of white smoke eliminating device with cooperation of flue gas waste heat and moisture recovery ) 是由 张山山 吴巧玲 姬海宏 宋华伟 于 2021-05-27 设计创作，主要内容包括：本发明烟气余热和水分回收协同消白烟装置的工作方法,它属于火电厂领域。本发明包括汽轮机低压缸、凝汽器、凝结水泵、第二换热器、除雾器、第一集水装置、第三换热器、低压再热器、冷却水喷洒装置、第二集水装置、集水池、第一换热器和脱硫吸收塔,汽轮机低压缸、凝汽器、凝结水泵、第二换热器、第一换热器、低压加热器依次相连,第二换热器配备除雾器和第一集水装置,汽轮机低压缸分别与低压再热器、第三换热器连接,第三换热器配备第二集水装置和冷却水喷洒装置；第一集水装置、第二集水装置与集水池连接；集水池与脱硫吸收塔连接,集水池与冷却水喷洒装置连接。本发明满足结构设计合理、高效回收烟气余温和水分,并有效消除白色烟羽等要求。(The invention discloses a working method of a white smoke eliminating device by using flue gas waste heat and moisture recovery in a synergistic manner, and belongs to the field of thermal power plants. The system comprises a steam turbine low-pressure cylinder, a condenser, a condensate pump, a second heat exchanger, a demister, a first water collecting device, a third heat exchanger, a low-pressure reheater, a cooling water spraying device, a second water collecting device, a water collecting tank, a first heat exchanger and a desulfurization absorption tower, wherein the steam turbine low-pressure cylinder, the condenser, the condensate pump, the second heat exchanger, the first heat exchanger and the low-pressure heater are sequentially connected, the second heat exchanger is provided with the demister and the first water collecting device, the steam turbine low-pressure cylinder is respectively connected with the low-pressure reheater and the third heat exchanger, and the third heat exchanger is provided with the second water collecting device and the cooling water spraying device; the first water collecting device and the second water collecting device are connected with the water collecting tank; the water collecting tank is connected with the desulfurization absorption tower and the cooling water spraying device. The invention meets the requirements of reasonable structural design, high-efficiency recovery of residual temperature and moisture of flue gas, effective elimination of white smoke plume and the like.)

1. A working method of a white smoke removing device with cooperation of flue gas waste heat and moisture recovery is characterized in that: the device comprises a steam turbine low-pressure cylinder (1), a condenser (2), a condensate pump (3), a second heat exchanger (4), a demister (5), a first water collecting device (6), a third heat exchanger (7), a low-pressure reheater (8), a cooling water spraying device (9), a second water collecting device (10), a cooling water pump (11), a water collecting tank (12), a water supplementing pump (13), a first heat exchanger (14), a desulfurization absorption tower (15), a chimney (16), a control valve (17) and a safety valve (18), wherein the first heat exchanger (14) and the second heat exchanger (4) are respectively arranged in an inlet flue and an outlet flue of the desulfurization absorption tower (15), and the steam turbine low-pressure cylinder (1), the condenser (2), the condensate pump (3), the second heat exchanger (4), the first heat exchanger (14) and the low-pressure heater (8) are sequentially connected; the second heat exchanger (4) is provided with a demister (5) and a first water collecting device (6); the third heat exchanger (7) is arranged between the second heat exchanger (4) and the chimney (16); the low-pressure steam turbine cylinder (1) is respectively connected with the low-pressure reheater (8) and the third heat exchanger (7), and a control valve (17) is arranged between the low-pressure steam turbine cylinder (1) and the third heat exchanger (7); the third heat exchanger (7) is provided with a second water collecting device (10) and a cooling water spraying device (9); the first water collecting device (6) and the second water collecting device (10) are connected with a water collecting tank (12); the water collecting tank (12) is connected with the desulfurization absorption tower (15), and the desulfurization water replenishing pump (13) is arranged between the water collecting tank (12) and the desulfurization absorption tower (15); the water collecting tank (12) is connected with the cooling water spraying device (9), and the cooling water pump (11) is arranged between the water collecting tank (12) and the cooling water spraying device (9); the safety valve (18) is arranged on the second water collecting device (10);

the working method of the smoke waste heat and moisture recovery cooperative white smoke elimination device comprises the following specific steps:

s1: the method comprises the following steps that firstly, flue gas is absorbed by condensed water through a first heat exchanger (14) and then cooled, the flue gas enters a desulfurization absorption tower (15) to become saturated flue gas, then enters a second heat exchanger (4) to be subjected to heat exchange and cooling by the condensed water, the cooled flue gas enters a third heat exchanger (7) to be heated and whitened by high-temperature hot flue gas pumped out by a low-pressure cylinder (1) of a steam turbine, and the whitened flue gas is discharged into the atmosphere from a chimney (16);

s2: condensed water of the condenser (2) enters a second heat exchanger (4) through a condensed water pump (3) to absorb the heat of the flue gas at the outlet of the desulfurization absorption tower (15), and then enters a first heat exchanger (14) to absorb the heat of the high-temperature flue gas at the inlet of the desulfurization absorption tower (15), so that the deep recovery of the flue gas waste heat is realized, and after the deep recovery of the flue gas waste heat is completed, the condensed water enters a low-temperature heater (8) to be reused after heat absorption;

s3: a certain amount of high-temperature flue gas is extracted by the steam turbine low-pressure cylinder (1), and enters the third heat exchanger (7) to heat the flue gas before entering the chimney (16), so that the white smoke elimination is realized;

s4: condensed water generated by the second heat exchanger (4) falls into the first water collecting device (6), cooling water of the third heat exchanger (7) enters the second water collecting device (10), both of the cooling water and the cooling water enter the water collecting tank (12), a part of water in the water collecting tank (12) enters the cooling water spraying device (9) of the third heat exchanger (7) through the condensed water pump (11) to cool and liquefy redundant exhaust gas, and liquefied water also enters the water collecting tank (12); the water in the water collecting tank (12) is supplemented to the desulfurization absorption tower (15) through a water supplementing pump (13).

Technical Field

The invention relates to a working method, in particular to a working method of a white smoke elimination device with cooperation of flue gas waste heat and moisture recovery, and belongs to the fields of white smoke elimination, waste heat utilization and moisture recovery of a thermal power plant.

Background

At present, the flue gas desulfurization of domestic coal-fired units mostly adopts a limestone-gypsum method process, in a wet desulfurization system, absorption liquid is directly contacted with high-temperature flue gas, and water in a desulfurizer solution absorbs heat and is vaporized, so that the flue gas is humidified and cooled, the moisture content of the flue gas is increased, and the dew point temperature of the flue gas is increased. When the steam saturated flue gas is directly discharged from a chimney, the outside temperature is more likely to be lower than the dew point temperature, and a large amount of water vapor is condensed into small water drops, so that the moisture condensation is more likely to occur, and the phenomenon of 'white smoke' is generated.

In addition, the inlet flue gas and the outlet flue gas of the wet desulphurization have certain recoverable waste heat, particularly the temperature of the inlet flue gas of the desulphurization is generally 90-140 ℃, the flue gas has huge waste heat recovery potential, and the temperature of the outlet flue gas is generally 50-60 ℃, and also has certain waste heat recovery potential. After the flue gas passes through the desulfurization system, the absorption liquid is in direct contact with the high-temperature flue gas, the moisture content of the outlet flue gas is increased, and the saturated steam flue gas has huge moisture recovery potential.

The invention discloses an invention patent named as a dual recycling system for waste heat and water in exhaust smoke of a boiler of a thermal power plant, wherein the publication date of the invention is 2017, 08 and 22 months, and the publication number of the invention is CN 107084384A. The system provided by the invention has two stages of heat and water recovery devices which are respectively arranged at two sides of a desulfurizing tower, wherein the first stage of heat and water recovery device is arranged in front of the desulfurizing tower, and the second stage of heat and water recovery device is arranged behind the desulfurizing tower; the first-stage heat and water recovery device consists of a flue gas cooler and a flue gas waste heat and water recovery device, the second-stage heat and water recovery device consists of a flue gas fine particulate matter and water collaborative removal device and a flue gas waste heat and water recovery device, and the whole system is formed by connecting a condensed water pipeline and a valve; the flue gas flows through this system, realizes the recovery of flue gas sensible heat, latent heat and moisture, and the sensible heat of retrieving and latent heat are all used for heating the condensate water, and the moisture of retrieving is used for condensate water moisturizing and desulfurizing tower moisturizing. The invention has good spontaneity, can recycle and utilize more than 80% of the waste heat of the discharged smoke and more than 40% of the moisture of the discharged smoke in the smoke, but can not well solve the problem that the waste heat of the smoke and the moisture are recycled to eliminate white smoke in a synergic manner, and has low working efficiency, so the invention also has the defects.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides the working method of the smoke waste heat and moisture recovery cooperative white smoke elimination device, which has the advantages of simple and reasonable structural design, safety, reliability, high-efficiency recovery of the waste heat and moisture of smoke, effective elimination of white smoke plume and convenient operation.

The technical scheme adopted by the invention for solving the problems is as follows: the working method of the smoke waste heat and moisture recovery cooperative white smoke elimination device is characterized in that: the device comprises a steam turbine low-pressure cylinder, a condenser, a condensate pump, a second heat exchanger, a demister, a first water collecting device, a third heat exchanger, a low-pressure reheater, a cooling water spraying device, a second water collecting device, a cooling water pump, a water collecting tank, a water supplementing pump, a first heat exchanger, a desulfurization absorption tower, a chimney, a control valve and a safety valve, wherein the first heat exchanger and the second heat exchanger are respectively arranged at an inlet flue and an outlet flue of the desulfurization absorption tower, and the steam turbine low-pressure cylinder, the condenser, the condensate pump, the second heat exchanger, the first heat exchanger and the low-pressure heater are sequentially connected; the second heat exchanger is provided with a demister and a first water collecting device; the third heat exchanger is arranged between the second heat exchanger and the chimney; the low-pressure cylinder of the steam turbine is respectively connected with the low-pressure reheater and the third heat exchanger, and a control valve is arranged between the low-pressure cylinder of the steam turbine and the third heat exchanger; the third heat exchanger is provided with a second water collecting device and a cooling water spraying device; the first water collecting device and the second water collecting device are connected with the water collecting tank; the water collecting tank is connected with the desulfurization absorption tower, and the desulfurization water replenishing pump is arranged between the water collecting tank and the desulfurization absorption tower; the water collecting tank is connected with the cooling water spraying device, and the cooling water pump is arranged between the water collecting tank and the cooling water spraying device; the safety valve is arranged on the second water collecting device;

the working method of the smoke waste heat and moisture recovery cooperative white smoke elimination device comprises the following specific steps:

s1: the method comprises the following steps that firstly, flue gas is subjected to heat absorption by condensed water through a first heat exchanger and then cooled, enters a desulfurization absorption tower to become saturated flue gas, then enters a second heat exchanger to be subjected to heat exchange and cooling by the condensed water, the cooled flue gas enters a third heat exchanger to be heated and whitened by high-temperature hot flue gas extracted by a low-pressure cylinder of a steam turbine, and the whitened flue gas is discharged into the atmosphere from a chimney;

s2: condensed water of the condenser enters the second heat exchanger through the condensed water pump to absorb the heat of the flue gas at the outlet of the desulfurization absorption tower and then enters the first heat exchanger to absorb the heat of the high-temperature flue gas at the inlet of the desulfurization absorption tower, so that the deep recovery of the waste heat of the flue gas is realized, and after the deep recovery of the waste heat of the flue gas is completed, the condensed water enters the low-temperature heater to be reused after absorbing heat;

s3: the low-pressure cylinder of the steam turbine extracts a certain amount of high-temperature flue gas, and the high-temperature flue gas enters the third heat exchanger to heat the flue gas before entering the chimney, so that the white elimination of the flue gas is realized;

s4: condensed water generated by the second heat exchanger falls into the first water collecting device, cooling water of the third heat exchanger enters the second water collecting device, the cooling water and the third water collecting device both enter the water collecting pool, a part of water in the water collecting pool enters the cooling water spraying device of the third heat exchanger through the condensed water pump to cool and liquefy redundant exhaust gas, and liquefied water also enters the water collecting pool; and water in the water collecting tank is supplemented to the desulfurization absorption tower through a water supplementing pump.

Compared with the prior art, the invention has the following advantages and effects: the whole structure is reasonable in design, the waste heat and the moisture of the smoke are efficiently recovered, and the requirements of white smoke plume and the like are effectively eliminated; the first heat exchanger and the second heat exchanger are used for heat exchange between the flue gas and the liquid; the third heat exchanger is used for heat exchange between the flue gas and the steam; the control valve can realize remote online control; the demister is arranged at the flue gas side outlet of the second heat exchanger and is used for removing condensed water in the flue gas; the first water collecting device is arranged at the bottom of the flue gas side outlet of the second heat exchanger and used for collecting the generated liquid water; the second water collecting device is arranged at the bottom of the steam side outlet of the third heat exchanger and used for collecting cooling water; the cooling water spraying device is used for cooling and liquefying the redundant exhaust gas; the safety valve is used for automatically releasing pressure when the internal pressure of the second water collecting device is overlarge.

Drawings

Fig. 1 is a schematic structural diagram of an apparatus according to an embodiment of the present invention.

In the figure: the system comprises a steam turbine low-pressure cylinder 1, a condenser 2, a condensate pump 3, a second heat exchanger 4, a demister 5, a first water collecting device 6, a third heat exchanger 7, a low-pressure reheater 8, a cooling water spraying device 9, a second water collecting device 10, a cooling water pump 11, a water collecting tank 12, a water replenishing pump 13, a first heat exchanger 14, a desulfurization absorption tower 15, a chimney 16, a control valve 17 and a safety valve 18.

Detailed Description

The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.

Examples are given.

Referring to fig. 1, the smoke waste heat and moisture recovery cooperative "white smoke abatement" device in this embodiment includes a steam turbine low pressure cylinder 1, a condenser 2, a condensate pump 3, a second heat exchanger 4, a demister 5, a first water collection device 6, a third heat exchanger 7, a low pressure reheater 8, a cooling water spray device 9, a second water collection device 10, a cooling water pump 11, a water collection tank 12, a water replenishing pump 13, a first heat exchanger 14, a desulfurization absorption tower 15, a chimney 16, a control valve 17, and a safety valve 18; the first heat exchanger 14 and the second heat exchanger 4 are respectively arranged on an inlet flue and an outlet flue of the desulfurization absorption tower 15, and the steam turbine low-pressure cylinder 1, the condenser 2, the condensate pump 3, the second heat exchanger 4, the first heat exchanger 14 and the low-pressure heater 8 are sequentially connected; the second heat exchanger 4 is provided with a demister 5 and a first water collecting device 6; the third heat exchanger 7 is arranged between the second heat exchanger 4 and the chimney 16; the low-pressure turbine cylinder 1 is respectively connected with the low-pressure reheater 8 and the third heat exchanger 7, and a control valve 17 is arranged between the low-pressure turbine cylinder 1 and the third heat exchanger 7; the third heat exchanger 7 is provided with a second water collecting device 10 and a cooling water spraying device 9; the first water collecting device 6 and the second water collecting device 10 are connected with a water collecting tank 12; the water collecting tank 12 is connected with the desulfurization absorption tower 15, and the desulfurization water replenishing pump 13 is arranged between the water collecting tank 12 and the desulfurization absorption tower 15; the water collecting tank 12 is connected with the cooling water spraying device 9, and the cooling water pump 11 is arranged between the water collecting tank 12 and the cooling water spraying device 9; a safety valve 18 is installed at the second water collecting device 10.

The first heat exchanger 14 and the second heat exchanger 4 are gas-liquid heat exchangers for heat exchange between flue gas and liquid; the third heat exchanger 7 exchanges heat for gas and steam and is used for exchanging heat between the flue gas and the steam.

The control valve 17 in this embodiment is an electric valve, and can realize remote online control.

The demister 5 of this embodiment is installed at the flue gas side outlet of the second heat exchanger 4, and is used for removing condensed water in the flue gas.

The first water collecting device 6 in this example is installed at the bottom of the flue gas side outlet of the second heat exchanger 4 for collecting the generated liquid water.

The second water collecting device 10 of the present example is installed at the bottom of the steam side outlet of the third heat exchanger 7 for collecting the cooling water.

The cooling water spraying device 9 is arranged at the upper part of the second water collecting device 10 and is used for cooling and liquefying redundant exhaust gas.

The safety valve 18 in this embodiment is a pneumatic safety valve, and is used for automatically releasing the pressure when the internal pressure of the second water collecting device 10 is too high.

The working method of the smoke waste heat and moisture recovery cooperative white smoke elimination device comprises the following steps:

s1: the flue gas firstly passes through the first heat exchanger 14, is cooled after being absorbed by condensed water, enters the desulfurization absorption tower 15 to become saturated flue gas, then enters the second heat exchanger 4 to be subjected to heat exchange and cooling by the condensed water, the cooled flue gas enters the third heat exchanger 7 to be heated and whitened by high-temperature hot flue gas pumped out by the steam turbine low-pressure cylinder 1, and the whitened flue gas is discharged into the atmosphere from a chimney 16;

s2: condensed water of the condenser 2 enters the second heat exchanger 4 through the condensed water pump 3 to absorb the heat of the flue gas at the outlet of the desulfurization absorption tower 15 and then enters the first heat exchanger 14 to absorb the heat of the high-temperature flue gas at the inlet of the desulfurization absorption tower 15, so that the deep recovery of the waste heat of the flue gas is realized, and after the deep recovery of the waste heat of the flue gas is completed, the condensed water enters the low-temperature heater 8 to be reused after heat absorption;

s3: the steam turbine low pressure cylinder 1 extracts a certain amount of high temperature flue gas, and the flue gas enters the third heat exchanger 7 to heat the flue gas before entering the chimney 16, so that the white smoke elimination is realized;

s4: condensed water generated by the second heat exchanger 4 falls into the first water collecting device 6, cooling water of the third heat exchanger 7 enters the second water collecting device 10, both the condensed water and the cooling water enter the water collecting pool 12, a part of water in the water collecting pool 12 enters the cooling water spraying device 9 of the third heat exchanger 7 through the condensed water pump 11 to cool and liquefy redundant exhaust gas, and liquefied water also enters the water collecting pool 12; the water in the water collecting tank 12 can be supplemented to the desulfurization absorption tower 15 through the water supplementing pump 13.

And will be apparent to those skilled in the art from the foregoing description.

In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an illustration of the structure of the present invention. Equivalent or simple changes in the structure, characteristics and principles of the invention are included in the protection scope of the patent. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.