WO2023050701A1

WO2023050701A1 - Low-temperature desulfurization and denitrification method and system for flue gas from coking plant

Info

Publication number: WO2023050701A1
Application number: PCT/CN2022/078044
Authority: WO
Inventors: 肖平; 汪世清; 李卫东; 许世森; 郜时旺; 刘练波; 牛红伟; 雷中辉; 易湘明
Original assignee: 中国华能集团清洁能源技术研究院有限公司; 华能湖南岳阳发电有限责任公司
Priority date: 2021-09-28
Filing date: 2022-02-25
Publication date: 2023-04-06
Also published as: CN113731161A; CN113731161B

Abstract

A low-temperature desulfurization and denitrification method and system for flue gas from a coking plant. The method comprises the following steps: reducing the temperature of flue gas to 120ºC-150ºC; desulfurizing the flue gas; dedusting the flue gas; reducing the temperature of the flue gas to 20ºC or below; desulfurizing and denitrifying the flue gas; and discharging the flue gas.

Description

Low-temperature desulfurization and denitrification method and system for coking plant flue gas

Cross References to Related Applications

This application is based on a Chinese patent application with application number 202111143265.3 and a filing date of September 28, 2021, and claims the priority of this Chinese patent application. The entire content of this Chinese patent application is hereby incorporated by reference into this application.

technical field

The present disclosure relates to the technical field of gas purification, in particular, to a method and system for low-temperature desulfurization and denitrification of flue gas from a coking plant.

Background technique

Due to the particularity of the production process of the coke oven, the hot flue gas discharged from the chimney contains sulfur dioxide, nitrogen oxides, and dust, among which the content of nitrogen oxides is relatively high. The flue gas needs to be desulfurized, denitrified and dust-removed before it can meet the emission requirements. In the related art, the treatment of the flue gas discharged from the coking plant needs to heat up the flue gas, but the denitrification method of the related art has a low denitrification efficiency.

Contents of the invention

The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent.

For this reason, the embodiments of the present disclosure propose a low-temperature desulfurization and denitrification method for coking plant flue gas. The low-temperature desulfurization and denitrification method for coking plant flue gas has the advantages of high desulfurization rate and high denitrification rate.

Embodiments of the present disclosure also propose a low-temperature desulfurization and denitrification system for coking plant flue gas. The low-temperature desulfurization and denitrification system for coking plant flue gas has the advantages of high desulfurization rate and high denitrification rate.

The low-temperature desulfurization and denitrification method for coking plant flue gas according to an embodiment of the present disclosure includes the following steps:

Lower the temperature of the flue gas to 120°C-150°C;

Desulfurizing the flue gas;

Dedusting the flue gas;

reducing the temperature of the flue gas to below 20°C;

Desulfurization and denitrification of the flue gas;

The flue gas is discharged.

The low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure reduces the temperature of the flue gas discharged from the coking plant to 120°C-150°C, and then performs the first desulfurization treatment. 120° C.-150° C.) has high desulfurization efficiency, which further increases the desulfurization rate of the low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure. The desulfurized flue gas is cooled again to reduce the temperature of the flue gas to below 20°C, and then the flue gas after the cooling treatment is subjected to desulfurization and denitrification treatment. The denitrification efficiency is high, which further increases the denitrification rate of the low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure.

In addition, the low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure performs multiple desulfurization treatments on the flue gas, thereby increasing the desulfurization rate of the low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure .

Therefore, the low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure has the advantages of high desulfurization rate and high denitrification rate.

In some embodiments, reducing the temperature of the flue gas to 120°C-150°C includes:

Pass the flue gas into the waste heat boiler to lower the temperature of the flue gas to 120°C-150°C.

In some embodiments, the reducing the temperature of the flue gas to below 20°C includes:

Pass the hot water in the waste heat boiler into the steam generator of the absorption refrigeration unit;

The flue gas is passed into the absorption refrigeration unit to exchange heat with the evaporator, so that the temperature of the flue gas is lowered to below 20°C.

In some embodiments, before the flue gas is passed into the absorption refrigeration unit to exchange heat with the evaporator, the flue gas is passed into a recooler to reduce the temperature of the flue gas to 30 ℃-60℃;

After the flue gas is desulfurized and denitrified, before the flue gas is discharged, the flue gas is passed into the recooler to cool the recooler.

In some embodiments, before the flue gas is passed into the recooler,

Passing the flue gas into the water cooler to reduce the temperature of the flue gas to 60°C-90°C;

Cooling water is fed into the water cooler to cool the water cooler.

The low-temperature desulfurization and denitrification system for coking plant flue gas according to an embodiment of the present disclosure includes:

A waste heat boiler, the waste heat boiler includes a first flue gas inlet, a first flue gas outlet and a first water outlet, and the flue gas can enter the waste heat boiler through the first flue gas inlet;

A desulfurization tower, the desulfurization tower includes a second flue gas inlet and a second flue gas outlet, the first flue gas outlet communicates with the second flue gas inlet, so that the flue gas is passed into the desulfurization tower , so as to desulfurize the flue gas;

An absorption refrigeration unit, the absorption refrigeration unit includes a steam generator and an evaporator, the steam generator includes a second water inlet, the evaporator includes a third flue gas inlet and a third flue gas outlet, the first A water outlet communicates with the second water inlet, so as to pass hot water in the waste heat boiler into the steam generator, and the second flue gas outlet communicates with the third flue gas inlet, so as to The flue gas is passed into the evaporator, thereby reducing the temperature of the flue gas;

A low-temperature adsorption tower, the low-temperature adsorption tower includes a fourth flue gas inlet and a fourth flue gas outlet, the third flue gas outlet communicates with the fourth flue gas inlet, so that the flue gas is passed into the low-temperature In the adsorption tower, the flue gas is desulfurized and denitrified.

The low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure cools the flue gas through the waste heat boiler to reduce the temperature of the flue gas. After cooling, the flue gas is desulfurized in the desulfurization tower. The desulfurization efficiency is high, so the desulfurization rate of the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure is increased. The flue gas after the desulfurization treatment of the desulfurization tower is cooled again by the absorption refrigeration unit, and the flue gas after cooling is subjected to desulfurization and denitrification treatment in the low-temperature adsorption tower. The denitrification rate of the low-temperature desulfurization and denitrification system used for coking plant flue gas in the embodiment. The denitrification rate of the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure can reach 98%.

In addition, the low-temperature desulfurization and denitration system for coking plant flue gas in the embodiment of the present disclosure performs multiple desulfurization treatments on the flue gas, thereby increasing the desulfurization rate of the low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure .

Therefore, the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure has the advantages of high desulfurization rate and high denitrification rate.

In some embodiments, the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiments of the present disclosure further includes a dust collector, the dust collector includes an air inlet and an air outlet, and the air inlet and the second flue gas The gas outlet is connected so that the flue gas is passed into the dust collector,

The gas outlet communicates with the third flue gas inlet, so that the second flue gas outlet communicates with the third flue gas inlet.

In some embodiments, the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiments of the present disclosure further includes a recooler, the recooler includes a fifth flue gas inlet and a fifth flue gas outlet, and the fifth The flue gas inlet communicates with the gas outlet so that the flue gas can be passed into the recooler to reduce the temperature of the flue gas,

The fifth flue gas outlet communicates with the third flue gas inlet so that the gas outlet communicates with the third flue gas inlet, and the recooler also includes a seventh flue gas inlet and a seventh flue gas inlet. outlet, the seventh flue gas inlet communicates with the fourth flue gas outlet, so that the flue gas can pass into the recooler, thereby cooling the recooler.

In some embodiments, the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure further includes a water cooler, the water cooler includes a sixth flue gas inlet and a sixth flue gas outlet, and the sixth flue gas The inlet is communicated with the gas outlet so that the flue gas is passed into the water cooler to reduce the temperature of the flue gas, and the sixth flue gas outlet is communicated with the fifth flue gas inlet so that The gas outlet communicates with the fifth flue gas inlet, and the water cooler further includes a third water inlet and a third water outlet, and the third water inlet is used to feed cooling water into the water cooler so as to The water cooler performs cooling.

In some embodiments, the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiments of the present disclosure further includes: a chimney; The tuyere is in communication with the seventh flue gas outlet, and the air outlet of the induced draft fan is in communication with the chimney, so as to discharge the flue gas.

Description of drawings

Fig. 1 is a schematic structural diagram of a low-temperature desulfurization and denitrification system for coking plant flue gas according to an embodiment of the present disclosure.

Fig. 2 is a schematic structural diagram of a low-temperature desulfurization and denitrification system for coking plant flue gas according to an embodiment of the present disclosure.

Reference signs:

Waste heat boiler 1; first flue gas inlet 11; first flue gas outlet 12; first water outlet 13; first water inlet 14;

Desulfurization tower 2; second flue gas inlet 21; second flue gas outlet 22;

Absorption refrigeration unit 3; steam generator 31; second water inlet 311; second water outlet 312;

Evaporator 32; third flue gas inlet 321; third flue gas outlet 322;

Low temperature adsorption tower 4; fourth flue gas inlet 41; fourth flue gas outlet 42;

Dust collector 5; air inlet 51; air outlet 52; dust outlet 53;

Recooler 6; first heat exchange component 61; fifth flue gas inlet 611; fifth flue gas outlet 612; second heat exchange component 62; seventh flue gas inlet 621; seventh flue gas outlet 622;

Water cooler 7; third heat exchange component 71; sixth flue gas inlet 711; sixth flue gas outlet 712; fourth heat exchange component 72; third water inlet 721; third water outlet 722;

induced draft fan 8; air inlet 81; air outlet 82; chimney 9.

Detailed ways

The present disclosure is made based on the inventors' discovery and recognition of the following facts and problems:

The difficulty of coke oven flue gas treatment is denitrification. Because SO ₂ in the flue gas will react with NH ₃ , if the temperature of the coke oven flue gas is too low, crystallization will occur, which will block the micropores on the surface of the denitrification catalyst and cause denitrification catalyst poisoning. The applicable temperature range of the relevant technology is 320°C-420°C, and the temperature of the flue gas from the coke oven exhaust to the flue gas treatment equipment is 180°C-300°C. The use of related technologies to treat the coke oven flue gas requires the heating of the coke oven flue gas treatment, and the denitrification efficiency of the denitrification method of the related art is low.

Embodiments of the present disclosure are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the figures are exemplary and are intended to explain the present disclosure and should not be construed as limiting the present disclosure.

As shown in FIG. 1 , the low-temperature desulfurization and denitrification system for coking plant flue gas according to an embodiment of the present disclosure includes a waste heat boiler 1 , a desulfurization tower 2 , an absorption refrigeration unit 3 and a low-temperature adsorption tower 4 .

The waste heat boiler 1 includes a first flue gas inlet 11 , a first flue gas outlet 12 and a first water outlet 13 , and flue gas can enter the waste heat boiler 1 through the first flue gas inlet 11 .

Specifically, as shown in FIG. 1 , the flue gas discharged from the coking plant (the flue gas temperature is 180°C-300°C) enters the waste heat boiler 1 through the first flue gas inlet 11 . It can be understood that the heat exchange between the flue gas and the waste heat boiler 1 can reduce the temperature of the high-temperature flue gas after the heat exchange between the flue gas and the waste heat boiler 1, wherein the temperature of the flue gas after lowering the temperature is between 120°C and 150°C, and the waste heat The water in boiler 1 heats up to hot water after absorbing the heat of the flue gas. The cooled flue gas is discharged from the first flue gas outlet 12 of the waste heat boiler 1 .

The desulfurization tower 2 includes a second flue gas inlet 21 and a second flue gas outlet 22, the first flue gas outlet 12 communicates with the second flue gas inlet 21, so that the flue gas is passed into the desulfurization tower 2, thereby desulfurizing the flue gas . Specifically, the flue gas discharged from the waste heat boiler 1 enters the desulfurization tower 2 through the second flue gas inlet 21, and the flue gas is desulfurized in the desulfurization tower 2, thereby removing sulfur compounds in the flue gas. After the flue gas is desulfurized, it is discharged from the second flue gas outlet 22 of the desulfurization tower 2 .

It can be understood that the height of the tower body of the desulfurization tower 2 is large, so that the flue gas in the desulfurization tower 24 can fully react in the desulfurization tower 2, so the embodiment of the present disclosure increases the volume of flue gas used in the coking plant. Desulfurization rate of low temperature desulfurization and denitrification method.

The absorption refrigeration unit 3 includes a steam generator 31 and an evaporator 32, the steam generator 31 includes a second water inlet 311, the evaporator 32 includes a third flue gas inlet 321 and a third flue gas outlet 322, the first water outlet 13 and The second water inlet 311 is communicated so as to pass the hot water in the waste heat boiler 1 into the steam generator 31 , the second flue gas outlet 22 is communicated with the third flue gas inlet 321 so as to pass the flue gas into the evaporator 32 , Thereby reducing the temperature of the flue gas.

Specifically, as shown in Figure 1, the flue gas treated by the desulfurization tower 2 enters the evaporator 32 through the third flue gas inlet 321, and the flue gas enters the evaporator 32 to exchange heat with the evaporator 32, and then the evaporator 32 The temperature of the flue gas is lowered to below 20° C., and the flue gas cooled by the evaporator 32 is discharged from the evaporator 32 through the third flue gas outlet 322 .

The low-temperature adsorption tower 4 comprises a fourth flue gas inlet 41 and a fourth flue gas outlet 42, and the third flue gas outlet 322 is communicated with the fourth flue gas inlet 41, so that the flue gas is passed into the low-temperature adsorption tower 4, thereby the flue gas Carry out desulfurization and denitrification.

Specifically, as shown in FIG. 1 , the flue gas that has been cooled is discharged through the third flue gas outlet 322 of the evaporator 32, and enters the low-temperature adsorption tower 4 from the fourth flue gas inlet 41 of the low-temperature adsorption tower 4 for desulfurization and desulfurization. For denitration treatment, the flue gas that has undergone desulfurization and denitrification treatment is discharged to the outside from the fourth flue gas outlet 42 .

The low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure cools the flue gas through the waste heat boiler 1 to reduce the temperature of the flue gas. After cooling, the flue gas is desulfurized in the desulfurization tower 2. The desulfurization efficiency is high, so the desulfurization rate of the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure is increased. The flue gas desulfurized by the desulfurization tower 2 is cooled again by the absorption refrigeration unit 3, and the flue gas after cooling is subjected to desulfurization and denitration treatment in the low-temperature adsorption tower 4. The flue gas denitrification efficiency after cooling again is high, so the increase The denitrification rate of the low-temperature desulfurization and denitrification system for coking plant flue gas according to the embodiment of the present disclosure is shown. The denitrification rate of the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure can reach 98%.

In some embodiments, the desulfurization tower 2 is provided with active coke for desulfurization. It can be understood that activated coke has a catalytic effect on the reaction of sulfur-containing compounds and oxygen in flue gas, and the surface of activated coke has micropores, which can absorb the reaction products of sulfur-containing compounds and oxygen, thereby achieving the goal of desulfurization. Effect.

In some embodiments, slaked lime may also be provided in the desulfurization tower 2 . Specifically, the desulfurization tower 2 desulfurizes the flue gas by reacting slaked lime with the flue gas, so the desulfurization tower 2 can remove sulfur compounds in the flue gas. Wherein, the desulfurization treatment of the flue gas by the desulfurization tower 2 includes dry desulfurization and semi-dry desulfurization.

In some embodiments, dry desulfurization is used to remove sulfur-containing compounds in flue dust, wherein dry slaked lime is used as an absorbent, and the flue gas in the desulfurization tower 2 reacts with dry slaked lime, thereby removing sulfur-containing compounds in the flue gas. In some embodiments, semi-dry desulfurization is used to remove sulfur compounds in the flue dust. Wherein, the slaked lime slurry is sprayed in the desulfurization tower 2, so that the slaked lime slurry is evenly distributed in the desulfurization tower 2, and the flue gas reacts with the slaked lime in the desulfurization tower 2, thereby removing sulfur compounds in the flue gas.

In some embodiments, the low-temperature adsorption tower 4 is provided with activated carbon. It can be understood that the activated carbon has a catalytic effect on the reaction of sulfur-containing compounds and oxygen in the flue gas, and the surface of the activated carbon has micropores, which can absorb sulfur-containing The product of the reaction between the compound and oxygen, and then achieve the effect of desulfurization. In addition, activated carbon catalyzes the reduction reaction of NO in the flue gas, and under the action of the reducing agent NH ₃ , NO is reduced to N ₂ , thereby achieving the purpose of denitrification and deamination.

In some embodiments, the waste heat boiler 1 further has a first water inlet 14 , the evaporator 32 further has a second water outlet 312 , and the second water outlet 312 communicates with the first water inlet 14 . The second water inlet 311 of the steam generator 31 communicates with the first water outlet 13 of the waste heat boiler 1 , and the first water inlet 14 of the waste heat boiler 1 communicates with the second water outlet 312 of the steam generator 31 . The hot water in the waste heat boiler 1 is discharged from the first water outlet 13 and enters the steam generator 31 through the second water inlet 311 . The hot water is discharged through the second water outlet 312 after being cooled by the steam generator 31 , and enters the waste heat boiler 1 from the first water inlet 14 of the waste heat boiler 1 to cool down the flue gas flowing into the waste heat boiler 1 . Furthermore, the water in the waste heat boiler 1 can be recycled, thus improving the utilization rate of water.

In some embodiments, as shown in FIG. 2 , the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure further includes a dust collector 5, and the dust collector 5 includes an air inlet 51 and an air outlet 52, and the air inlet 51 communicates with the second flue gas outlet 22 so as to pass the flue gas into the dust collector 5 , and the gas outlet 52 communicates with the third flue gas inlet 321 so that the second flue gas outlet 22 communicates with the third flue gas inlet 321 .

Specifically, the flue gas treated by the desulfurization tower 2 is discharged from the second flue gas outlet 22, and enters the dust collector 5 through the air inlet 51, and the dust collector 5 performs dust removal treatment on the flue gas, wherein the dust collector 5 can remove the flue gas The soot and active coke in the dust and the flue gas after dedusting are discharged from the gas outlet 52 of the dust collector 5 .

In addition, the dust collector 5 also includes a dust outlet 53, wherein the dust and active coke removed from the flue gas are discharged from the dust outlet 53 of the dust collector 5, thereby preventing the dust and active coke remaining in the dust collector 5 from causing secondary damage to the flue gas. secondary pollution.

In some embodiments, as shown in FIG. 2 , the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure further includes a recooler 6, and the recooler 6 includes a fifth flue gas inlet 611 and a fifth flue gas inlet 611. The gas outlet 612, the fifth flue gas inlet 611 communicates with the gas outlet 52, so as to pass the flue gas into the recooler 6, thereby reducing the temperature of the flue gas, the fifth flue gas outlet 612 communicates with the third flue gas inlet 321, Such that the gas outlet 52 communicates with the third flue gas inlet 321 .

Specifically, the dust treated by the dust collector 5 is discharged through the gas outlet 52, enters the recooler 6 through the fifth flue gas inlet 611, and the recooler 6 cools the flue gas, and the cooled flue gas is cooled from the recooler The fifth flue gas outlet 612 of the device 6 is discharged into the evaporator 32 through the third flue gas inlet 321, and then the temperature of the flue gas is lowered again.

In some embodiments, the recooler 6 further includes a seventh flue gas inlet 621 and a seventh flue gas outlet 622, the seventh flue gas inlet 621 communicates with the fourth flue gas outlet 42, so that the flue gas can be passed into the recooler 6, so as to cool the recooler 6. Specifically, the flue gas treated by the low-temperature adsorption tower 4 is discharged from the fourth flue gas outlet 42 and enters the recooler 6 through the seventh flue gas inlet 621 . Further, the flue gas is discharged from the seventh flue gas outlet 622 of the recooler 6 .

In some embodiments, the recooler 6 includes a first heat exchange assembly 61 and a second heat exchange assembly 62, the first heat exchange assembly 61 can exchange heat with the second heat exchange assembly 62, and the first heat exchange assembly 61 includes a second heat exchange assembly 62 Five flue gas inlets 611 and fifth flue gas outlets 612 . The second heat exchange component 62 includes a seventh flue gas inlet 621 and a seventh flue gas outlet 622 .

Specifically, as shown in Figure 2, the flue gas treated by the dust collector 5 enters the first heat exchange assembly 61 from the fifth flue gas inlet 611, and the flue gas discharged from the cryogenic adsorption tower 4 enters through the seventh flue gas inlet 621. The second heat exchanging component 62, the flue gas in the first heat exchanging component 61 exchanges heat with the flue gas in the second heat exchanging component 62 through the first heat exchanging component 61, thereby reducing the temperature.

It can be understood that the flue gas discharged from the low-temperature adsorption tower 4 is cooled through the recooler 6, and after the recooler 6 is cooled, the temperature is lowered again by the evaporator 32. Therefore, the temperature of the flue gas discharged from the low-temperature adsorption tower 4 lower than the temperature of the flue gas in the first heat exchange assembly 61, that is, the temperature of the flue gas in the second heat exchange assembly 62 is lower than the temperature of the flue gas in the first heat exchange assembly 61, so the second heat exchange assembly 62 The temperature of the flue gas in the first heat exchange component 61 can be reduced.

In some embodiments, as shown in FIG. 2 , the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure further includes a water cooler 7, and the water cooler 7 includes a sixth flue gas inlet 711 and a sixth flue gas outlet 712, the sixth flue gas inlet 711 communicates with the gas outlet 52, so as to pass the flue gas into the water cooler 7, thereby reducing the temperature of the flue gas, and the sixth flue gas outlet 712 communicates with the fifth flue gas inlet 611, so that the The gas port 52 communicates with the fifth flue gas inlet 611 .

Specifically, the dust treated by the dust collector 5 is discharged through the exhaust port, and enters the water cooler 7 through the sixth flue gas inlet 711, and further, the water cooler 7 performs cooling treatment on the flue gas. The cooled flue gas is discharged from the sixth flue gas outlet 712 and enters the recooler 6 through the fifth flue gas inlet 611 .

Further, the water cooler 7 further includes a third water inlet 721 and a third water outlet 722 , the third water inlet 721 is used to feed cooling water into the water cooler 7 so as to cool the water cooler 7 . Specifically, the cooling water enters the water cooler 7 from the third water inlet 721 to exchange heat with the flue gas of the water cooler 7, thereby reducing the temperature of the flue gas. The cooling water that has exchanged heat with the flue gas is discharged from the third water outlet 722 .

Further, the water cooler 7 includes a third heat exchange assembly 71 and a fourth heat exchange assembly 72, the third heat exchange assembly 71 can exchange heat with the fourth heat exchange assembly 72, and the third heat exchange assembly 71 includes a sixth flue gas inlet 711 and the sixth flue gas outlet 712 , the fourth heat exchange component 72 includes a third water inlet 721 and a third water outlet 722 .

Specifically, the flue gas treated by the dust collector 5 enters the third heat exchange assembly 71 from the sixth flue gas inlet 711, and the cooling water enters the fourth heat exchange assembly 72 from the third water inlet 721, so that the flue gas can pass through The third heat exchange component 71 exchanges heat with the cooling water in the fourth heat exchange component 72 . The treated flue gas is discharged from the sixth flue gas outlet 712 of the third heat exchange component 71 , and the cooling water after heat exchange with the flue gas is discharged from the third water outlet 722 of the fourth heat exchange component 72 .

In some embodiments, as shown in FIG. 2 , the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure includes a chimney 9 and an induced draft fan 8 .

The induced fan 8 includes an air inlet 81 and an air outlet 82. The air inlet 81 of the induced fan 8 communicates with the seventh flue gas outlet 622, and the air outlet 82 of the induced fan 8 communicates with the chimney 9 to discharge the flue gas.

Specifically, the flue gas discharged from the evaporator 32 is discharged from the seventh flue gas outlet 622 into the induced draft fan 8 , further, the flue gas is discharged from the air outlet 82 of the induced draft fan 8 . It can be understood that the induced draft fan 8 can achieve the circulation speed of flue gas in the low-temperature desulfurization and denitrification system for coking plant flue gas in the embodiment of the present disclosure.

The low-temperature desulfurization and denitrification method for coking plant flue gas according to the embodiments of the present disclosure will be described below with reference to the accompanying drawings. The low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure is implemented by using the above-mentioned low-temperature desulfurization and denitrification system for coking plant flue gas.

Lower the temperature of the flue gas to 120°C-150°C;

Desulfurizing the flue gas;

Dedusting the flue gas;

reducing the temperature of the flue gas to below 20°C;

Desulfurization and denitrification of the flue gas;

The flue gas is discharged.

In some embodiments, as shown in FIG. 1 , reducing the temperature of the flue gas to 120°C-150°C includes: passing the flue gas into a waste heat boiler to reduce the temperature of the flue gas to 120°C-150°C.

Specifically, the flue gas discharged from the coking plant enters the waste heat boiler 1 through the first flue gas inlet 11 . The flue gas exchanges heat with the waste heat boiler 1 to reduce the temperature of the high-temperature flue gas, wherein the temperature of the flue gas after lowering the temperature is 120°C-150°C, and the water in the waste heat boiler 1 absorbs the heat of the flue gas and heats up to become hot water. The cooled flue gas is discharged from the first flue gas outlet 12 of the waste heat boiler 1 .

The flue gas discharged from the waste heat boiler 1 enters the desulfurization tower 2 through the second flue gas inlet 21, and the flue gas is desulfurized in the desulfurization tower 2 to remove sulfur compounds in the flue gas. After the flue gas is desulfurized, it is discharged from the second flue gas outlet 22 of the desulfurization tower 2 .

The flue gas treated by the desulfurization tower 2 is discharged from the second flue gas outlet 22, and enters the dust collector 5 through the air inlet 51, and then the dust collector 5 performs dust removal treatment on the flue gas, wherein the dust collector 5 can remove dust from the flue gas. The flue dust and activated coke, the flue gas after dedusting is discharged from the gas outlet 52 of the dust collector 5 .

Therefore, the low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure reduces the temperature of the flue gas discharged from the coking plant to 120°C-150°C, and then performs the first desulfurization treatment, and the flue gas after cooling (Temperature at 120° C.-150° C.) has high desulfurization efficiency, which further increases the desulfurization rate of the low-temperature desulfurization and denitrification method for coking plant flue gas in the embodiment of the present disclosure.

In some embodiments, as shown in Figure 1, reducing the temperature of the flue gas to below 20°C includes:

Pass the hot water in the waste heat boiler to the steam generator 31 of the absorption refrigeration unit. Specifically, the hot water in the waste heat boiler 1 is discharged from the first water outlet 13 and enters the steam generator 31 through the second water inlet 311 . The hot water is discharged through the second water outlet 312 after being cooled by the steam generator 31 , and enters the waste heat boiler 1 from the first water inlet 14 of the waste heat boiler 1 to cool down the flue gas flowing into the waste heat boiler 1 . Furthermore, the water in the waste heat boiler 1 can be recycled, thus improving the utilization rate of water.

The flue gas is passed into the absorption refrigeration unit to exchange heat with the evaporator, so that the temperature of the flue gas drops below 20°C. Specifically, the flue gas treated by the desulfurization tower 2 enters the first heat exchange component 61 of the evaporator 32 through the third flue gas inlet 321 . After the flue gas enters the first heat exchange component 61, it exchanges heat with the second heat exchange component 62, thereby reducing the temperature of the flue gas in the first heat exchange component 61 to below 20°C. The flue gas cooled by the evaporator 32 exits the evaporator 32 from the third flue gas outlet 322 .

Further, the cooled flue gas is discharged through the third flue gas outlet 322 of the evaporator 32, and enters the cryogenic adsorption tower 4 from the fourth flue gas inlet 41 of the cryogenic adsorption tower 4 for desulfurization and denitration treatment. Further, the flue gas that has undergone desulfurization and denitration treatment is discharged from the fourth flue gas outlet 42 .

In some embodiments, before the flue gas is passed into the absorption refrigeration unit to exchange heat with the evaporator, the flue gas is passed into the recooler to reduce the temperature of the flue gas to 30°C-60°C.

Specifically, as shown in Figure 2, the dust treated by the dust collector 5 is discharged through the exhaust port, and enters the recooler 6 through the fifth flue gas inlet 611, and the recooler 6 cools the flue gas to make the flue gas The temperature of the gas drops to 30°C-60°C. The cooled flue gas is discharged from the fifth flue gas outlet 612 of the recooler 6 .

In addition, after the flue gas is desulfurized and denitrified, before the flue gas is discharged, the flue gas is passed into the recooler to cool the recooler.

Specifically, the low-temperature flue gas treated by the low-temperature adsorption tower 4 is discharged from the fourth flue gas outlet 42, and the low-temperature flue gas enters the second heat exchange assembly 62 of the recooler 6 through the seventh flue gas inlet 621, and then the A heat exchange component 61 is used for cooling. The flue gas after heat exchange is discharged from the seventh flue gas outlet 622 of the recooler 6 .

In some embodiments, as shown in Figure 2, before the flue gas is passed into the recooler, the flue gas is passed into a water cooler to lower the temperature of the flue gas to 60°C-90°C.

Specifically, the dust treated by the dust collector 5 is discharged through the exhaust port, and enters the water cooler 7 through the sixth flue gas inlet 711, and the water cooler 7 exchanges heat with the flue gas through cooling water to reduce the temperature of the flue gas to 60 ℃-90℃. The cooled flue gas is discharged from the sixth flue gas outlet 712, and enters the recooler 6 through the fifth flue gas inlet 611.

In some embodiments, cooling water is fed into the water cooler to cool the water cooler.

Specifically, the flue gas treated by the dust collector 5 enters the third heat exchange assembly 71 from the sixth flue gas inlet 711, and the cooling water enters the fourth heat exchange assembly 72 from the third water inlet 721, so that the flue gas can pass through The third heat exchange component 71 exchanges heat with the cooling water in the fourth heat exchange component 72 .

In describing the present disclosure, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientations or positional relationships indicated by "radial", "circumferential", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying the referred devices or elements Must be in a particular orientation, constructed, and operate in a particular orientation, and thus should not be construed as limiting on the present disclosure.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In this disclosure, terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense, for example, it can be a fixed connection or a detachable connection unless otherwise clearly defined and limited. , or integrated; can be mechanically connected, can also be electrically connected or can communicate with each other; can be directly connected, can also be indirectly connected through an intermediary, can be the internal communication of two components or the interaction relationship between two components, unless expressly defined otherwise. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present disclosure according to specific situations.

In the present disclosure, unless otherwise clearly stated and limited, a first feature being "on" or "under" a second feature may mean that the first and second features are in direct contact, or that the first and second features are indirect through an intermediary. touch. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In this disclosure, the terms "one embodiment," "some embodiments," "example," "specific examples," or "some examples" mean a specific feature, structure, material, or feature described in connection with the embodiment or example. Features are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure, and those skilled in the art can make the above-mentioned embodiments within the scope of the present disclosure. The embodiments are subject to changes, modifications, substitutions and variations.

Claims

A low-temperature desulfurization and denitrification method for coking plant flue gas, characterized in that it comprises the following steps:

Lower the temperature of the flue gas to 120°C-150°C;

Desulfurizing the flue gas;

Dedusting the flue gas;

reducing the temperature of the flue gas to below 20°C;

Desulfurization and denitrification of the flue gas;

The flue gas is discharged.
The low-temperature desulfurization and denitrification method for coking plant flue gas according to claim 1, characterized in that,

Said reducing the temperature of the flue gas to 120°C-150°C includes:

Pass the flue gas into the waste heat boiler to reduce the temperature of the flue gas to 120°C-150°C.
The low-temperature desulfurization and denitrification method for coking plant flue gas according to claim 2, wherein said reducing the temperature of the flue gas to below 20°C comprises:

Pass the hot water in the waste heat boiler into the steam generator of the absorption refrigeration unit;

The flue gas is passed into the absorption refrigeration unit to exchange heat with the evaporator, so that the temperature of the flue gas is lowered to below 20°C.
The low-temperature desulfurization and denitrification method for coking plant flue gas according to claim 3, characterized in that before the flue gas is passed into the absorption refrigeration unit to exchange heat with the evaporator, the flue gas The gas is passed into the recooler to reduce the temperature of the flue gas to 30°C-60°C;

After the flue gas is desulfurized and denitrified, before the flue gas is discharged, the flue gas is passed into the recooler to cool the recooler.
The low-temperature desulfurization and denitrification method for coking plant flue gas according to claim 4, characterized in that, before the flue gas is passed into the recooler,

Pass the flue gas into a water cooler to lower the temperature of the flue gas to 60°C-90°C;

Cooling water is fed into the water cooler to cool the water cooler.
A low-temperature desulfurization and denitrification system for coking plant flue gas, characterized in that it includes:

A waste heat boiler, the waste heat boiler includes a first flue gas inlet, a first flue gas outlet and a first water outlet, and the flue gas can enter the waste heat boiler through the first flue gas inlet;

A desulfurization tower, the desulfurization tower includes a second flue gas inlet and a second flue gas outlet, the first flue gas outlet communicates with the second flue gas inlet, so that the flue gas is passed into the desulfurization tower , so as to desulfurize the flue gas;

An absorption refrigeration unit, the absorption refrigeration unit includes a steam generator and an evaporator, the steam generator includes a second water inlet, the evaporator includes a third flue gas inlet and a third flue gas outlet, the first A water outlet communicates with the second water inlet, so as to pass hot water in the waste heat boiler into the steam generator, and the second flue gas outlet communicates with the third flue gas inlet, so as to The flue gas is passed into the evaporator, thereby reducing the temperature of the flue gas;

A low-temperature adsorption tower, the low-temperature adsorption tower includes a fourth flue gas inlet and a fourth flue gas outlet, the third flue gas outlet communicates with the fourth flue gas inlet, so that the flue gas is passed into the low-temperature In the adsorption tower, the flue gas is desulfurized and denitrified.
The low-temperature desulfurization and denitrification system for coking plant flue gas according to claim 6, further comprising a dust collector, the dust collector includes an air inlet and an air outlet, and the air inlet and the second The flue gas outlet is connected so that the flue gas can be passed into the dust collector,

The gas outlet communicates with the third flue gas inlet, so that the second flue gas outlet communicates with the third flue gas inlet.
The low-temperature desulfurization and denitrification system for coking plant flue gas according to claim 7, further comprising a recooler, the recooler includes a fifth flue gas inlet and a fifth flue gas outlet, and the first 5. The flue gas inlet communicates with the gas outlet so that the flue gas can be passed into the recooler to reduce the temperature of the flue gas,

The fifth flue gas outlet communicates with the third flue gas inlet so that the gas outlet communicates with the third flue gas inlet, and the recooler also includes a seventh flue gas inlet and a seventh flue gas inlet. outlet, the seventh flue gas inlet communicates with the fourth flue gas outlet, so that the flue gas can pass into the recooler, thereby cooling the recooler.
The low-temperature desulfurization and denitrification system for coking plant flue gas according to claim 8, further comprising a water cooler, the water cooler includes a sixth flue gas inlet and a sixth flue gas outlet, and the sixth flue gas The gas inlet is connected with the gas outlet so that the flue gas is passed into the water cooler to reduce the temperature of the flue gas, and the sixth flue gas outlet is connected with the fifth flue gas inlet to The gas outlet is communicated with the fifth flue gas inlet, and the water cooler further includes a third water inlet and a third water outlet, and the third water inlet is used to feed cooling water into the water cooler, so that The water cooler is cooled.
The low-temperature desulfurization and denitrification system for coking plant flue gas according to claim 9, further comprising:

chimney; and

An induced fan, the induced fan includes an air inlet and an air outlet, the air inlet of the induced fan communicates with the seventh flue gas outlet, and the air outlet of the induced fan communicates with the chimney, so that the The fumes are emitted.