CN210434269U

CN210434269U - Dust and white removing device for tail gas three-circulation loop after wet desulphurization of boiler flue gas

Info

Publication number: CN210434269U
Application number: CN201921138830.5U
Authority: CN
Inventors: 张明; 李妮妮; 薛晶; 阮建林; 侯勇团
Original assignee: SHAANXI XINYU SURFACE ENGINEERING CO LTD
Current assignee: SHAANXI XINYU SURFACE ENGINEERING CO LTD
Priority date: 2019-07-19
Filing date: 2019-07-19
Publication date: 2020-05-01
Anticipated expiration: 2029-07-19

Abstract

The utility model belongs to the technical field of heat transfer technique and environmental engineering among the chemical engineering, a three circulation loop dust removal white device of tail gas behind boiler flue gas wet flue gas desulfurization is related to, including the desulfurizing tower, the wash bowl, plate heat exchanger, the cooling tower, the desulfurizing tower is flue gas cooling section from bottom to top in proper order, the absorption section, the cooling water washing section, high-efficient defogging section, reheat section, chimney, flue gas cooling section lateral wall is provided with the flue gas inlet port, boiler flue gas gets into the flue gas cooling section of desulfurizing tower from the flue gas inlet port, boiler flue gas after the cooling gets into the cooling water washing section through the absorption section afterwards, after the boiler flue gas after washing gets rid of partial liquid drop through high-efficient defogging section, get into reheat section after heaing up, boiler flue gas after the intensification emits into the atmosphere through direct vent chimney. The utility model discloses a white process that disappears of dust removal is realized to three independent endless loop, to newly-built project investment province, and then the tower body range of change is little to the transformation project, and newly-increased equipment area is little outside the tower, and the investment is economized.

Description

Dust and white removing device for tail gas three-circulation loop after wet desulphurization of boiler flue gas

Technical Field

The utility model belongs to the technical field of heat transfer technique and environmental engineering among the chemical engineering, a three circulation circuit dust removal and white elimination devices of tail gas behind boiler flue gas wet flue gas desulfurization is related to.

Background

China still uses coal as main fossil energy and SO generated by coal-fired boiler₂The emission is the main cause of acid rain formation and also the main pollutant causing air pollution. China has become the first major coal-producing nation in the world, and with the comprehensive implementation of the atmospheric pollutant emission standard GB13223-2011 of thermal power plants in China, the wet desulphurization efficiency is high, so the wet desulphurization device for flue gas desulphurization of the coal-fired boiler flowers all the time in China. Meanwhile, a plurality of problems are derived secondarily, such as trailing phenomenon caused by aerosol generated by an ammonia method, outlet smoke saturation, and long white smoke caused by high smoke plume humidity. At present, colored smoke plumes are treated in China, and various smoke whitening technologies are brought forward.

In order to reduce or eliminate white plume emitted from a wet flue pipe, the current technical genre mainly includes several directions. (1) The first technical route is as follows: the GGH technology is adopted, namely outlet wet flue gas is heated by high-temperature flue gas entering the tower through the GGH, and the smoke exhaust temperature is increased, so that the aim of eliminating white smoke is fulfilled. (2) The second technical route is as follows: and (3) adopting a slurry cooling technology, cooling by a desulfurization solution to reduce the temperature of the flue gas, and then passing the outlet wet flue gas through a GGH or steam heater to realize temperature rise and white elimination. (3) The technical route is three: the outlet wet flue gas is condensed and then heated and whitened by a GGH or steam heater.

The three technical routes in the prior art respectively have the following problems:

(1) the problem of the first technical route is as follows: the equipment is huge and is influenced by the corrosion and the dust deposition of acid dew points, and the operation period is short.

(2) The second technical route has the following problems: slurry cooling makes water balance difficult to control, difficult to operate, and slurry coolers are prone to fouling, plugging and wear.

(3) The third technical route has the following problems: the wet flue gas at the outlet is indirectly condensed by adopting a heat exchanger, so that the installation and equipment cost is higher.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a three circulation circuit dust removal of boiler flue gas wet flue gas desulfurization back tail gas white device that disappears, the equipment of solving the prior art route existence is huge and receive the corruption and the influence of deposition of acid dew point, and the operation cycle is short, the thick liquid cooling makes the water balance uncontrollable, is difficult to operate, and the easy scale deposit of thick liquid cooler blocks up wearing and tearing scheduling problem.

The utility model discloses an implementation process as follows:

the utility model provides a three circulation circuit dust removal white device that disappears of tail gas behind boiler flue gas wet flue gas desulfurization, includes desulfurizing tower, wash bowl, plate heat exchanger, cooling tower, the desulfurizing tower is flue gas cooling section, absorption section, cooling water washing section, high-efficient defogging section, reheat section, chimney from bottom to top in proper order, the flue gas cooling section lateral wall of desulfurizing tower is provided with the flue gas inlet port, boiler flue gas enters the flue gas cooling section of desulfurizing tower from the flue gas inlet port, and the boiler flue gas after the cooling gets into the cooling water washing section through the absorption section afterwards, and after the boiler flue gas after the washing got rid of part liquid drop through high-efficient defogging section, got into reheat section intensification back, the boiler flue gas after the intensification discharged the atmosphere through direct vent chimney, the desulfurizing tower is connected with wash bowl, plate heat exchanger respectively, the wash bowl is connected with plate heat exchanger, plate heat exchanger is connected with the cooling tower.

Further, a down-flow pipe is arranged at the lower end of the cooling water washing section and connected with a washing tank, a supplement water pipe is arranged at the upper part of the washing tank and connected with the flue gas cooling section, a first valve is arranged on the supplement water pipe, a fresh process water pipe is arranged at the upper end of the washing tank, and the fresh process water pipe supplements fresh process water for the washing tank.

Further, a cooling water spray head is arranged in the cooling water washing section, and the cooling water spray head forms a spray layer of the cooling water washing section; the high-efficient defogging section is 2 high-efficient combination formula defroster groups.

Further, a built-in reheating heat exchanger is arranged in the reheating section, the built-in reheating heat exchanger is installed and fixed on a supporting beam in the desulfurizing tower, a heating steam inlet and a condensed water outlet are arranged on the side wall of the reheating section of the desulfurizing tower, the heating steam inlet is connected with a heating steam generator through a heating steam pipe, the condensed water outlet is connected with a condensed liquid refining device through a condensed water pipe, the heat source of the built-in reheating heat exchanger adopts low-pressure heating steam for heating, the heating steam generator generates heating steam, the heating steam enters the built-in reheating heat exchanger in the reheating section from a heating steam inlet on the side wall of the reheating section through the heating steam pipe, condensation is performed after heat exchange to generate condensed water, the condensed water enters the condensate refining device from a condensed water pipe through a condensed water outlet, and the heating steam generator and the condensate refining device are common structures in the prior art.

Further, the plate heat exchanger is made of 316L stainless steel, TA1 titanium alloy or 2205 duplex alloy steel.

Further, a first circulating pump is arranged between the rinsing bath and the plate heat exchanger.

Furthermore, the rinsing bath is connected with a first circulating pump through a first circulating pipe, the first circulating pump is connected with the plate heat exchanger through a second circulating pipe, the plate heat exchanger is connected with the cooling water rinsing section through a third circulating pipe, and a circulating pipe valve is arranged on the second circulating pipe.

Furthermore, the rinsing bath is connected with a first circulating pump through a first circulating pipe, the first circulating pump is connected with the cooling water rinsing section through an adjusting pipe, and an adjusting pipe valve is arranged on the adjusting pipe.

Further, a fourth circulating pipe is arranged on the side wall of the lower part of the cooling tower, a second circulating pump is arranged on the fourth circulating pipe, the fourth circulating pipe is connected with the plate type heat exchanger, a fifth circulating pipe is arranged on the side wall of the upper part of the cooling tower, and the fifth circulating pipe is connected with the plate type heat exchanger; the cooling tower is an open type cooling tower or an evaporative type cooling tower.

Furthermore, cooling water in the cooling tower is pressurized by the second circulating pump, then sequentially passes through the fourth circulating pipe, the plate heat exchanger and the fifth circulating pipe to circulate, and then returns to the cooling tower.

Heating steam generator can be replaced by the abundant low pressure heating steam of power plant or boiler. The 2 groups of efficient combined type demisters are multilayer pp material coalescence type wire mesh efficient demisting structures.

The utility model discloses an actively the effect:

(1) boiler flue gas wet flue gas desulfurization back tail gas three-cycle return circuit dust removal disappears and whitely installs and adopts washing water cooling method, and it is very big to adopt external high-efficient plate heat exchanger heat transfer coefficient, and in the washing water walking board of the area of washing pump export, the velocity of flow is fast, is difficult for the scale deposit, and heat transfer area is little, and the appearance is compact, and the slab can be dismantled, makes things convenient for artifical maintenance clearance, and the investment is economized, can practice thrift investment more than 40%, and area is little. The prior art usually adopts a built-in tilting and submerging type cooling method for a circulation box, the flow rate of washing water in a water trough (outside a pipe) of the process is low, residual slurry solids from flue gas at an absorption section can cause the outer part of a heat exchange pipe to be covered, the efficiency can be gradually reduced, long-period operation is difficult to guarantee, and overhauling and cleaning are difficult.

(2) The cooling tower that three circulation circuit dust removal of boiler flue gas wet flue gas desulfurization back tail gas disappears white device and adopts is open-type cooling tower or evaporation formula cooling tower.

(3) The utility model discloses a module heater can be dismantled for built-in fin formula to built-in reheat heat exchanger that white device of three circulation circuit dust removals of boiler flue gas wet flue gas desulfurization back tail gas adopted, the tubular product matter can be the stainless steel, the fin material can be 304 or 316L stainless steel, perhaps 2205 two-way alloy steel, and adopt low pressure pressurized steam to heat and belong to phase transition heat transfer, intraductal condensation heat transfer coefficient is very high, and adopt fin increase outside of tubes clean flue gas heat transfer coefficient, total heat transfer coefficient is big, consequently required heat transfer area is less, because the tower sectional area is big, it is less to occupy highly in the tower, about 400 give other care of 600mm height, be particularly suitable for old tower white intensification transformation, to newly-built device, the investment is more sparingly. The steam in the reheating section 15 flows away from the pipe to release phase change heat, and wet flue gas flowing outside the heating pipe enhances heat transfer due to the fins, reduces gas phase thermal resistance outside the pipe, increases the total heat transfer coefficient, increases the temperature difference, and is favorable for quick temperature rise reheating. The prior art generally adopts an external heating medium water heating and heat exchange method, belongs to non-phase change heat transfer and has small heat transfer coefficient, a front heat exchanger of the process is arranged in a flue, and cannot realize self-cleaning, the surface of the heat exchanger is easily covered by ash content of flue gas, so that the heat transfer efficiency is reduced, and long-period operation cannot be realized.

(4) Boiler flue gas wet flue gas desulfurization back tail gas three-cycle return circuit dust removal white device that disappears is provided with the auxiliary line that is used for adjusting the temperature winter and adjusts the pipe promptly, and it is according to the difference of flue gas load, through control adjusting valve, adopts partial washing water to walk plate heat exchanger bypass and adjusts the temperature.

(5) Boiler flue gas wet flue gas desulfurization back tail gas three-circulation loop dust removal and white device's 2 high-efficient combination formula defroster of group be the high-efficient defogging structure of multilayer pp material coalescence formula silk screen, and the export liquid drop is steerable within 30mg Nm 3.

Drawings

FIG. 1 is a process flow diagram of a dust and white removing device of a tail gas three-circulation loop after wet desulphurization of boiler flue gas;

in the figure, 1 a desulfurizing tower, 2 a washing tank, 3 a plate heat exchanger, 4 a cooling tower, 11 a flue gas cooling section, 12 an absorption section, 13 a cooling water washing section, 131 a cooling water spray head, 14 a high-efficiency demisting section, 15 a reheating section, 151 a heating steam pipe, 152 a condensate pipe, 16 a chimney, 17 a flue gas inlet, 50 a downcomer, 51 a supplement water pipe, 511 a first valve, 52 a fresh process water pipe, 53 a first circulating pipe, 54 a second circulating pipe, 541 a circulating pipe valve, 55 a third circulating pipe, 56 a regulating pipe, 561 a regulating pipe valve, 57 a fourth circulating pipe, 58 a fifth circulating pipe, 61 a first circulating pump and 62 a second circulating pump.

Detailed Description

The present invention will be further described with reference to the following examples.

In order to solve the equipment that prior art route exists huge and receive the corruption and the influence of deposition of acid dew point, the operation cycle is short, the thick liquid cooling makes the water balance difficult to control, is difficult to operate, and the easy scale deposit of thick liquid cooler blocks up wearing and tearing scheduling problem, the utility model provides a simple, reliable, the interior three circulation loop dust removal of boiler flue gas wet flue gas desulfurization back tail gas white device that integrates in the tower.

Example 1

The device for removing dust and white dust in the tail gas three-circulation loop after wet desulfurization of boiler flue gas is shown in fig. 1 and comprises a desulfurizing tower 1, a rinsing bath 2, a plate heat exchanger 3 and a cooling tower 4, wherein the desulfurizing tower 1 sequentially comprises a flue gas cooling section 11, an absorption section 12, a cooling rinsing section 13, a high-efficiency demisting section 14, a reheating section 15 and a chimney 16 from bottom to top, a flue gas inlet 17 is formed in the side wall of the flue gas cooling section 11 of the desulfurizing tower 1, the boiler flue gas enters the flue gas cooling section 11 of the desulfurizing tower 1 from the flue gas inlet 17, the cooled boiler flue gas then enters the cooling rinsing section 13 through the absorption section 12, the boiler flue gas after being rinsed is subjected to partial liquid drop removal by the high-efficiency demisting section 14 and then enters the reheating section 15 for warming, the warmed boiler flue gas is discharged into the atmosphere through the direct discharging chimney 16, and the desulfurizing tower 1 is respectively connected with the rinsing bath 2 and, the rinsing bath 2 is connected with a plate heat exchanger 3, and the plate heat exchanger 3 is connected with a cooling tower 4. The lower end of the cooling water washing section 13 is provided with a downcomer 50, the downcomer 50 is connected with the washing tank 2, the upper part of the washing tank 2 is provided with a supplement water pipe 51, the supplement water pipe 51 is connected with the flue gas cooling section 11, the supplement water pipe 51 is provided with a first valve 511, the upper end of the washing tank 2 is provided with a fresh process water pipe 52, and the fresh process water pipe 52 supplements fresh process water for the washing tank 2. A cooling water spray head 131 is arranged in the cooling water washing section 13, and the cooling water spray head 131 forms a spray layer of the cooling water washing section 13; the efficient demisting section 14 is 2 groups of efficient combined demisters. A built-in reheating heat exchanger is arranged in the reheating section 15, the built-in reheating heat exchanger is installed and fixed on a supporting beam in the desulfurizing tower 1, a heating steam inlet and a condensed water outlet are arranged on the side wall of the reheating section 15 of the desulfurizing tower 1, the heating steam inlet is connected with the heating steam generator through a heating steam pipe 151, the condensed water outlet is connected with the condensed liquid refining device through a condensed water pipe 152, the heat source of the built-in reheating heat exchanger is heated by adopting low-pressure heating steam, the heating steam generator generates heating steam, the heating steam enters the built-in reheating heat exchanger in the reheating section 15 from a heating steam inlet on the side wall of the reheating section 15 through a heating steam pipe 151, condensation is performed after heat exchange to generate condensed water, the condensed water enters the condensate refining device from a condensed water pipe 152 through a condensed water outlet, and the heating steam generator and the condensate refining device are of common structures in the prior art. The plate heat exchanger 3 is made of 316L stainless steel, TA1 titanium alloy or 2205 duplex alloy steel, the plate thickness of the plate heat exchanger 3 is 0.4-0.6mm, the channel width is 8mm, the corrugation depth is 4mm, and the plate heat exchanger 3 is fixed by adopting a bolt compression type or a welding type. A first circulating pump 61 is arranged between the rinsing bath 2 and the plate heat exchanger 3. The washing tank 2 is connected with a first circulating pump 61 through a first circulating pipe 53, the first circulating pump 61 is connected with the plate heat exchanger 3 through a second circulating pipe 54, the plate heat exchanger 3 is connected with the cooling water washing section 13 through a third circulating pipe 55, and a circulating pipe valve 541 is arranged on the second circulating pipe 54. And simultaneously, arranging an auxiliary line pipeline: the rinsing bath 2 is connected with a first circulating pump 61 through a first circulating pipe 53, the first circulating pump 61 is connected with the cooling and rinsing section 13 through an adjusting pipe 56, and an adjusting pipe valve 561 is arranged on the adjusting pipe 56. A fourth circulating pipe 57 is arranged on the lower side wall of the cooling tower 4, a second circulating pump 62 is arranged on the fourth circulating pipe 57, the fourth circulating pipe 57 is connected with the plate heat exchanger 3, a fifth circulating pipe 58 is arranged on the upper side wall of the cooling tower 4, and the fifth circulating pipe 58 is connected with the plate heat exchanger 3; the cooling tower 4 is an open cooling tower or an evaporative cooling tower. The cooling water in the cooling tower 4 is pressurized by the second circulating pump 62, and then sequentially circulates through the fourth circulating pipe 57, the plate heat exchanger 3 and the fifth circulating pipe 58 and then returns to the cooling tower 4.

Example 2

The boiler design capacity of a certain chemical enterprise is 4 multiplied by 150t/h, the original initial desulfurization design is calcium spraying in the boiler, the boiler builds a flue gas ammonia desulfurization device, a boiler-tower process is adopted, sub-saturation absorption and a steam evaporation crystallization process outside the tower are carried out, and the full load flue gas amount of a single tower is about 18.5 multiplied by 10⁴Nm3/h, the designed coal sulfur content is 1%, the designed outlet sulfur dioxide emission concentration can reach below 35mg, the designed outlet nitrogen oxide can reach below 50mg, the designed operation is only about 15mg of dust, the original flue gas outlet smoke exhaust temperature is 51 ℃, and the ultra-clean index can not be met. And is accompanied by the phenomenon of raindrops in the outlet flue gas.

Reform transform original device according to fig. 1, wash the raw water promptly and spray the layer and reform transform, increase and spray the coverage to satisfy the requirement of new liquid-gas ratio, demolish 1 original group of roof defroster, increase 2 high-efficient combination formula demisters and increase 3m with former barrel, and newly-increased supporting beam, newly-increased a set of built-in fin steam heater, tower outer wall flange mouth, be connected with heating steam pipe 151, condensate pipe 152 respectively. The plate heat exchanger 3 is designed to have a thermal load of 320 x 10⁴kcal/h, heat exchange area of 357m²Design a circulation volume of 400m³The temperature of cold water at the water inlet washing section is 32 ℃, the temperature of circulating upper water from the cooling tower 4 is 30 ℃, the designed return water temperature is 35 ℃ under the working condition of summer, and the designed treated water quantity of the closed cooling tower is 650m³And/h, the design temperature difference is 5 ℃, two circulating water pumps are adopted, one is opened and the other is prepared, two cycles are realized, the heat of the first cycle is transferred to the second cycle through the plate exchange, and finally the heat is brought into the atmosphere through the closed cooling tower 4. After the boiler flue gas wet desulphurization tail gas three-circulation loop dust and white removal device is practiced, the temperature of the flue gas after washing is reduced to 45 ℃, and then the flue gas is passed through a multi-stage combined demisting device, so that the content of liquid drops entering a reheating temperature raising section is less than 30mg/Nm³The temperature of the flue gas is increased by steam heating in the pipeTo 70 ℃, the atmosphere is amplified by the chimney exhaust. In the implementation of the embodiment, the online monitoring of the ultra-clean dust outlet instrument shows that the outlet dust data is 3.6mg/Nm³The control requirement of ultra-clean emission dust is realized, and the white elimination of the flue gas is realized.

The working principle of the dust and white removing device for the tail gas three-circulation loop after wet desulphurization of the boiler flue gas is as follows: (1) one circulation: the boiler flue gas passes through a flue gas cooling section 11 and an absorption section 12 in the desulfurizing tower 1 and enters a cooling water washing section 13, so that saturated wet flue gas is atomized by cold water, sprayed, cooled, dehumidified and dedusted, then the flue gas goes to a high-efficiency demisting section 14, most liquid drops are removed, and then the flue gas enters a reheating section 15. The dust-containing water returned from the cooling and washing section 13 returns to the washing tank 2 through the downcomer 50, and the dust-containing water is pressurized by the first circulating pump 61, then sent to the in-plate channel of the plate heat exchanger 3 for cooling, and then sent to the spray layer of the cooling and washing section 13 for cooling the flue gas, which is a cycle. (2) And (2) two cycles: circulating water of an outer plate channel of the plate heat exchanger 3 comes from the cooling tower 4, is pressurized by the second circulating pump 62 and then is sent to the plate heat exchanger 3 to exchange heat with water used for washing in the plate, and circulating return water after temperature rise returns to the cooling tower 4, which is a two-cycle process. (3) Three cycles: the flue gas after washing cooling is demisted through the high-efficiency demisting section 14, enters the reheating section 15, is heated and then is discharged into the atmosphere through the direct-discharge chimney 16, the heating heat source of the reheating section 15 is heated by adopting low-pressure heating steam, and the condensed water out of the reheating section 15 returns to the condensate refining device through the condensate pipe 152, which is a three-cycle process. When the flue gas is washed by the circulated water, the liquid-gas ratio is not lower than 2.1L/Nm³The temperature difference of the first circulating water after heat exchange by the plate heat exchanger 3 is suitable to be 5-8 ℃, the heat exchange cold source is the second circulating cooling water, the temperature difference of the second circulating cooling water before and after plate heat exchange by the plate heat exchanger 3 is not less than 5 ℃ in summer, and the temperature difference of the water temperature of the first circulating water and the water temperature of the second circulating water is not less than 2 ℃. The total logarithmic heat transfer temperature difference of the plate heat exchanger 3 is not more than 4 ℃, and the heat transfer process with small temperature difference is adopted. The heating steam pressure of the three cycles is not lower than 0.5MPa (A), the design temperature of the unsaturated flue gas at the outlet is not lower than 70 ℃, and the heating steam quantity can be controlled according to the external climate condition until the white smoke disappears. The rinsing bath 4 is periodically filled with make-up waterThe dust-containing water discharged from the pipe 51 is used as make-up water for the flue gas cooling section 11, and fresh process water is supplemented to maintain the water balance of the rinsing bath 4, so that the concentration of the dust in the absorption liquid decreases from top to bottom of the tower. The regulating pipe 56 is used as a working condition in winter to save circulating water.

Compared with the prior art, the utility model discloses a white process that disappears of dust is realized to three independent endless loop, to newly-built project investment province, then tower body range of change is little to the transformation project, and newly-increased equipment area is little outside the tower, and the investment is economized. The heat transfer coefficient of water in the plate heat exchanger 3 to water can be up to 3000W/m²The other heat exchangers can not meet the requirement, the plate gap is small, the structure is compact, and the heat exchange area provided by unit volume is 250-1000m²/m²And the tower type solar cell can be made into a tower type so as to save the occupied area. The three-cycle heating adopts steam heating, the heat transfer temperature difference is large, the heat transfer coefficient of the tubular fins is large, the required heat exchange area is small, and the sectional area of the tower is large, so that the height occupied by the reheat heat exchanger is small, and the workload of the change of the tower body is small no matter a new device or an old device is reconstructed. The cooling water of the two circulation loops adopts circulating cooling water, the cooling tower can be an open type or a closed type, the circulating water quality is required to be stable, and the cooling tower is not easy to scale and does not contain visible solid suspended matters after being treated by adding medicine.

The method for removing dust and white in the boiler flue gas wet desulphurization tail gas three-circulation loop dust and white removing device comprises the following steps:

(1) flue gas desulfurization: the boiler flue gas is cooled by the sprayed absorption liquid through the flue gas cooling section 11 in the desulfurizing tower 1, the moisture of the absorption liquid is evaporated and continuously concentrated, most of the smoke dust is washed, the flue gas reaching the saturation temperature enters the absorption section 12, the flue gas is continuously and circularly absorbed by the sprayed absorption liquid in the absorption section 12, and the flue gas is washed again to remove dust and remove SO₂For the purpose of absorption, the absorbent is replenished in the absorption section 12.

(2) Cooling, condensing and dedusting flue gas: the desulfurized saturated wet flue gas from the absorption section 12 passes through the gas-lifting partition plate and then enters the cooling water washing section 13 to be sprayed with cold water by circulation, so that the temperature of the flue gas is reduced by 5-6 ℃, and residual dust in the flue gas is condensed as condensation nuclei in the form of liquid drops and mixed into falling circulating hot water. The heat transfer direction in the process is from gas phase to liquid phase, the water temperature is lower, the saturated vapor pressure of corresponding water is also low, the partial pressure of gas phase vapor is higher than that of liquid phase, vapor is transferred from the gas phase to the liquid phase, namely, condensation of water occurs, in the area, the liquid phase obtains sensible heat from the gas phase and latent heat released by vapor condensation, and the process is characterized in that the heat and mass are carried out in the same direction, and the water temperature is increased. The dust-containing water after temperature reduction and dust removal is supplemented into the flue gas temperature reduction section 11 through the rinsing bath 2, and the fresh process water is supplemented into the rinsing bath 2 again, so that the water balance of the rinsing bath 2 is realized, and the concentration of dust in circulating water in the rinsing bath 2 is reduced.

(3) Demisting wet flue gas: the saturated flue gas from the cooling water washing section 13 passes through a high-efficiency demisting section 14 to remove most of liquid drops, and the high-efficiency demisting section 14 adopts a plurality of layers of pp coalescent microporous wire nets, so that the content of the outlet mist drops is controlled at 30mg/Nm³In the method, the mechanical moisture is recovered to the maximum extent and then enters the reheating section 15 so as to reduce the steam consumption of the reheating section.

(4) Flue gas reheating section 15: the demisted wet flue gas enters the reheating section 15 to be heated and then is discharged into the atmosphere through a direct exhaust chimney 16, a heating heat source of the reheating section 15 adopts low-pressure heating steam for heating, and condensed water out of the reheating section 15 returns to a condensate refining device, which is a three-cycle process.

(5) Cooling by circulating water: the water in the rinsing tank 4 is pressurized to be first circulating water, the first circulating water is cooled by second circulating water from the cooling tower 4 through the plate heat exchanger 3, and the second circulating water is returned to the cooling tower 4 for cooling treatment after being heated.

The foregoing is a more detailed description of the invention, taken in conjunction with the specific preferred embodiments, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of conceiving, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.

Claims

1. The utility model provides a three circulation circuit dust removal and white elimination devices of tail gas after boiler flue gas wet flue gas desulfurization which characterized in that: including desulfurizing tower (1), wash bowl (2), plate heat exchanger (3), cooling tower (4), desulfurizing tower (1) is flue gas cooling section (11), absorption section (12), cooling water washing section (13), high-efficient defogging section (14), reheat section (15), chimney (16) from bottom to top in proper order, flue gas cooling section (11) lateral wall of desulfurizing tower (1) is provided with flue gas inlet port (17), boiler flue gas gets into flue gas cooling section (11) of desulfurizing tower (1) from flue gas inlet port (17), and boiler flue gas after the cooling gets into cooling water washing section (13) through absorption section (12) afterwards, and after the boiler flue gas after the washing got rid of part liquid drop through high-efficient defogging section (14), gets into reheat section (15) after the intensification, and boiler flue gas after the intensification goes into the atmosphere through direct vent chimney (16), desulfurizing tower (1) respectively with wash bowl (2), The plate heat exchanger (3) is connected, the rinsing bath (2) is connected with the plate heat exchanger (3), and the plate heat exchanger (3) is connected with the cooling tower (4).

2. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 1, characterized in that: the lower extreme of cooling washing section (13) is provided with downcomer (50), downcomer (50) are connected with wash bowl (2), wash bowl (2) upper portion is provided with supplementary water pipe (51), supplementary water pipe (51) are connected with flue gas cooling section (11), be provided with first valve (511) on supplementary water pipe (51), wash bowl (2) upper end is provided with fresh technology water pipe (52), fresh technology water pipe (52) supply fresh technology water for wash bowl (2).

3. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 1, characterized in that: a cooling water spray head (131) is arranged in the cooling water washing section (13), and the cooling water spray head (131) forms a spray layer of the cooling water washing section (13); the efficient demisting section (14) is 2 groups of efficient combined demisters.

4. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 1, characterized in that: the device is characterized in that a built-in reheating heat exchanger is arranged in the reheating section (15), the built-in reheating heat exchanger is fixedly arranged on a supporting beam in a desulfurizing tower (1), a heating steam inlet and a condensate outlet are formed in the side wall of the reheating section (15) of the desulfurizing tower (1), the heating steam inlet is connected with a heating steam generator through a heating steam pipe (151), the condensate outlet is connected with a condensate refining device through a condensate pipe (152), a heat source of the built-in reheating heat exchanger is heated by low-pressure heating steam, the heating steam generator generates heating steam, the heating steam enters the built-in reheating heat exchanger in the reheating section (15) from the heating steam inlet in the side wall of the reheating section (15) through the heating steam pipe (151), the condensate is condensed after heat exchange to generate condensate, and the condensate enters the condensate refining device through the condensate outlet from the condensate pipe (152), the heating steam generator and the condensate refining device are common structures in the prior art.

5. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 1, characterized in that: the plate heat exchanger (3) is made of 316L stainless steel, TA1 titanium alloy or 2205 duplex alloy steel.

6. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 1, characterized in that: and a first circulating pump (61) is arranged between the rinsing bath (2) and the plate heat exchanger (3).

7. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 6, characterized in that: the washing tank (2) is connected with a first circulating pump (61) through a first circulating pipe (53), the first circulating pump (61) is connected with the plate heat exchanger (3) through a second circulating pipe (54), the plate heat exchanger (3) is connected with the cooling water washing section (13) through a third circulating pipe (55), and a circulating pipe valve (541) is arranged on the second circulating pipe (54).

8. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 6, characterized in that: the washing tank (2) is connected with a first circulating pump (61) through a first circulating pipe (53), the first circulating pump (61) is connected with the cooling water washing section (13) through a regulating pipe (56), and a regulating pipe valve (561) is arranged on the regulating pipe (56).

9. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 1, characterized in that: a fourth circulating pipe (57) is arranged on the side wall of the lower part of the cooling tower (4), a second circulating pump (62) is arranged on the fourth circulating pipe (57), the fourth circulating pipe (57) is connected with the plate type heat exchanger (3), a fifth circulating pipe (58) is arranged on the side wall of the upper part of the cooling tower (4), and the fifth circulating pipe (58) is connected with the plate type heat exchanger (3); the cooling tower (4) is an open type cooling tower or an evaporative type cooling tower.

10. The boiler flue gas wet desulphurization after-tail gas three-circulation loop dust and white removal device according to claim 9, characterized in that: and cooling water in the cooling tower (4) is pressurized by a second circulating pump (62), then sequentially passes through a fourth circulating pipe (57), the plate heat exchanger (3) and a fifth circulating pipe (58) to circulate, and then returns to the cooling tower (4).