WO2017045602A1 - Coke oven flue gas desulfurization and denitrification combined purification process and apparatus - Google Patents

Abstract

A coke oven flue gas desulfurization and denitrification combined purification process and apparatus. The process comprises the following steps: desulfurizing coke oven flue gas at low temperature drop by means of a rotating spray semi-dry method in a desulfurization system; filtering particles in a dust removal manner in a dust removal and denitrification system, and denitrating the coke oven flue gas desulfurized at the low temperature drop and filtered in the dust removal manner in a dust removal and denitrification integrated device (3a) by using a selective catalytic reduction method; and returning the denitrated flue gas to a coke oven flue (6), and discharging the flue gas by means of a coke oven chimney (7). The apparatus comprises: an induced draught system, a desulfurization system, and a dust removal and denitrification system.

Description

Coke oven flue gas desulfurization and denitration combined purification process and device Technical field

The invention relates to the technical field of coke oven flue gas purification, in particular to a coke oven flue gas desulfurization and denitration combined purification process and device.

Background technique

In recent years, the state clearly the coking industry in SO _2, coke oven flue gas emission concentration index in NO _X, the requirements of ₂ NO _X emissions of SO, strictly controlled. Coal-fired power plant flue gas, high concentrations of SO ₂ and NO _X, of atmospheric pollution, desulfurization, denitrification work carried out early, current methods is quite mature, significant effect desulfurization and denitration. However, in the case of the coke oven flue gas, due to its own characteristics, the desulfurization and denitration technology of the power plant is not suitable for the desulfurization and denitrification of the coke oven flue gas. The specific reasons are as follows:

(1) The temperature of the coke oven flue gas is relatively low, generally between 180 °C and 290 °C.

(2) The SO ₂ content in the coke oven flue gas is generally 100-200 mg/Nm ³ . For the coking plant with high organic sulfur content in the raw coal or serious coke oven leakage, the SO in the coke oven flue gas ₂ content can reach 350mg/Nm ³ or more.

(3) The new coking plant, the exhaust gas recirculation technique, heating means segmentation technology can be effectively controlled in the NO _X content of <500mg / Nm ^3; For existing business or special area, can not be met by improving the coke oven heating method NO _X emission standards, measures must be taken after the denitration of flue gas.

(4) The coking method requires that the coke oven chimney must be kept in a hot standby state to ensure the normal and safe production of the coke oven; the temperature of the coke oven flue gas after desulfurization and denitrification purification must be higher than the flue gas dew point temperature, and should not be lower than 130 °C. .

(5) The actual operation of the coke oven shows that as the coke oven age increases, the furnace wall will inevitably lead to cross-leakage; the tar produced in the carbonization chamber will be inserted into the coke oven flue gas, and the tar is a strong viscous substance. A potential threat to the catalyst that can cause permanent damage to the catalyst.

Since the temperature of the coke oven flue gas is lower than the temperature of the conventional SCR catalyst of the power plant, and the flue gas contains SO ₂ , the conventional SCR denitration method of the power plant directly generates a large amount of ammonium sulfate salt, blocks the catalyst, and the tar in the flue gas. The viscous component must adhere to the surface of the catalyst, causing permanent damage and failure to properly denitrify. The direct use of the normal temperature wet desulfurization of the power plant will cause the temperature of the coke oven flue gas to fail to meet the emission requirements. Although the low temperature problem can be solved by heating the coke oven flue gas, it will cause energy waste and increase the investment and operating costs. Therefore, it is necessary to develop a desulfurization and denitration purification process and device for coke oven flue gas.

Summary of the invention

technical problem

The invention provides a coke oven flue gas desulfurization and denitration combined purification process and device, and combines rotary spray drying desulfurization with low temperature SCR denitrification to realize high-efficiency desulfurization and denitrification of coke oven flue gas, and the process is simple, accounting for The land area is small and the equipment investment is small.

Technical solutions

In order to achieve the above object, the present invention provides a coke oven flue gas desulfurization and denitration combined purification process, comprising the following steps:

In the desulfurization system, the coke oven flue gas is subjected to rotary spray semi-dry method for low-temperature desulfurization; in the dust removal and denitration system, the particulate matter is subjected to dust removal and filtration; and the selective catalytic reduction method is used for desulfurization and dust removal after low temperature drop. The coke oven flue gas is denitrified in the dust removal and denitrification integrated equipment; and the flue gas after denitration is sent back to the coke oven flue and discharged through the coke oven chimney.

In addition, the preferred solution is that the rotary spray semi-dry method low temperature desulfurization process comprises: the coke oven flue gas is sucked out from the coke oven flue at the root of the coke oven chimney by the induced draft fan, and is transported into the desulfurization through the flue gas pipeline. a system; wherein the desulfurization system is composed of a desulfurization tower, a sodium-based desulfurizer solution preparation unit, a circulating ash solution preparation unit, and a solution delivery unit; and in the desulfurization system, a sodium-based desulfurizer that is transported to the desulfurization tower top tank through the solution delivery unit The solution is atomized into a sodium-based desulfurizer particle of 50-100 μm by a nebulizer; the flue gas stream of the coke oven is uniformly distributed in the desulfurization tower through a flue gas distributor at the top of the desulfurization tower, and the sodium-based desulfurizing agent after atomization The fine particles are fully reacted in the desulfurization tower to form sodium sulfite and sodium sulfate, thereby removing SO ₂ from the flue gas of the coke oven, and the flue gas after desulfurization of the coke oven flue gas enters the dust removal and denitration. system.

In addition, the preferred solution is that the dust removal and filtration process of the particulate matter comprises: the dust removal and denitration system is provided with a dust removal filter bag, a desulfurization ash collection and transportation device, and the flue gas first enters the filter bag purification function section of the dust removal and denitration integrated device, the flue. The dust in the gas is blocked outside the filter bag and adheres to the surface of the filter bag, and the pressure equalization of the filter bag resistance layer causes the flue gas to be evenly distributed on the cross section of the filter layer.

In addition, a preferred solution is to denitrify the coke oven flue gas subjected to low temperature desulfurization and dust removal filtration by a selective catalytic reduction method, including: the filtered flue gas is subjected to a mixed pyrolysis regeneration section and injected. ammonia mixed, and then into functional segments denitration catalyst, NO _x in the flue gas is reduced to N ₂ in the ammonia catalyst denitration.

In addition, a preferred solution is that the particulate matter in the flue gas filtered by the dust removal and denitration integrated device and the reactant formed by the desulfurization are transported to the circulating ash solution preparation unit through the desulfurization ash collection and conveying device to prepare a circulating ash solution. After that, it is sent to the top tank at the top of the desulfurization tower through the solution conveying unit, and participates in the desulfurization process of the coke oven flue gas, so that the unreacted sodium-based desulfurizing agent is fully utilized.

In addition, the preferred solution is that in the dust removal and denitration system, the ammonia gas is mixed and diluted with the purified flue gas extracted by the ammonia dilution fan in the ammonia gas-flue gas mixer, and then sent to the dust removal and denitration integrated device for denitration. reaction.

In addition, a preferred solution is that the gas hot blast stove periodically sends the high temperature pyrolysis gas to the mixed pyrolysis regeneration section in the dust removal and denitration integrated equipment to realize in situ pyrolysis regeneration of the denitration catalyst.

In addition, the present invention also provides a coke oven flue gas desulfurization and denitration combined purification device, comprising an air induction system, a desulfurization system and a dust removal and denitration system, wherein the air introduction system is used for attracting and returning the coke oven flue gas, The coke oven flue gas circulation purification provides power; the desulfurization system is used to remove SO ₂ from the coke oven flue gas; the dust removal and denitration system is used to dedust the flue gas after desulfurization, and then the flue gas after dedusting The gas is subjected to denitration treatment.

In addition, a preferred solution is that the air intake system includes a flue gas duct, an induced draft fan disposed on the flue gas duct, and a wind electric control valve disposed on the flue gas duct between the coke oven flue and the desulfurization tower, and the setting The air supply electric valve on the flue gas pipeline between the induced draft fan and the coke oven flue; wherein the induced draft fan is equipped with a variable frequency motor or a coupler or a permanent magnet governor, and the air blower is adjusted to adjust the wind The electric control valve provides the pressure required for normal operation of the desulfurization system and the dust removal and denitration system.

In addition, a preferred solution is that the desulfurization system includes a desulfurization tower, a sodium-based desulfurizer solution preparation unit, a circulating ash solution preparation unit, and a solution delivery unit; wherein a coke oven flue gas inlet and an atomizer are disposed at the top of the desulfurization tower. The top tank and the flue gas distributor are connected to the atomizer at the liquid outlet of the top tank, and the liquid inlet of the top tank is connected to the sodium-based desulfurizer solution preparation unit and the circulating ash solution preparation unit.

In addition, a preferred solution is that the sodium-based desulfurizer solution preparation unit includes a sodium-based desulfurizer storage bin, a variable frequency discharge valve, a weighing feeder, a dosing tank, a solution tank, and a heating water tank; and, for preparing a sodium base The desulfurizer solution is used for desulfurization of the coke oven flue gas.

In addition, a preferred solution is that the circulating ash solution preparation unit comprises a desulfurization ash silo, a variable frequency discharge valve, a fixed frequency discharge valve, a weighing feeder, a circulating ash solution tank; and, for preparing the collected desulfurization ash The solution is reused after reusing the sodium-based desulfurizing agent therein.

In addition, a preferred solution is that the solution delivery unit comprises a sodium-based desulfurizer solution pump, a circulating ash solution pump and a solution delivery pipe, a valve; and, for conveying the formulated sodium-based desulfurizer solution and the circulating ash solution to the Top can.

In addition, the preferred solution is that the dust removal and denitration system comprises an integrated dust removal and denitration device, an ammonia dilution fan, an ammonia gas-flue gas mixer and a desulfurization ash collection and transportation device; and the dust removal and denitration integrated device includes a filter bag purification from bottom to top. Functional section, mixed pyrolysis regeneration section, denitration catalyst functional section;

The flue gas pipeline drawn from the coke oven flue is connected to the desulfurization tower and the dust removal and denitration integrated equipment in turn; the dust removal and denitration integrated equipment is connected to the induced draft fan; the atomizer at the top of the desulfurization tower is connected with the top tank, and is respectively connected by the solution conveying unit. The sodium-based desulfurizer solution preparation unit and the circulating ash solution preparation unit, and the circulating ash solution preparation unit is connected to the bottom ash bin of the dust removal and denitration integrated device through the desulfurization ash collection and transportation device.

In addition, a preferred solution is that the filter bag purifying functional section includes a ash silo, a closed ash discharge valve, a flue gas inlet, a gas flow uniform baffle, a filter bag, and a pulse blowing device;

The ash silo is arranged under the dust removal and denitration integrated arrangement, the closed ash discharge valve is arranged at the ash silo discharge port, the flue gas inlet is arranged on the side wall of the upper part of the filter bag purifying functional section, and the filter bag is vertically embedded in the flower The inside of the plate hole is evenly distributed along the longitudinal direction, and the airflow uniform baffle is disposed between the flue gas inlet and the filter bag, and the upper part of the filter bag is provided with a pulse blowing device.

In addition, a preferred solution is that the mixed pyrolysis regeneration section includes a jet pyrolysis gas delivery injection structure, an ammonia spray structure, and a mixed current sharing structure;

The pyrolysis gas conveying injection structure comprises a plurality of air supply ducts arranged in parallel, each air supply duct is provided with an air volume regulating valve, and the air supply duct of the orifice plate is arranged on the air supply duct of the desulfurization tower; the ammonia spray structure is arranged Above the pyrolysis gas transport injection structure body, a plurality of parallel sprayed ammonia pipelines are arranged, each of which has an ammonia spray regulating valve, and an ammonia injection nozzle is uniformly distributed on the ammonia spray pipeline; the mixed current sharing structure is arranged Above the ammonia spray structure, it is composed of 1 to 4 layers of porous plates having a curved corrugation or an angular corrugation shape, and adjacent layers are staggered at an angle of 90° in the corrugation direction.

In addition, a preferred solution is that the denitration catalyst functional section includes a denitration catalyst and a purified flue gas outlet, the denitration catalyst is disposed in two to four layers, and the purified flue gas outlet is disposed in the dust removal and denitration. The top of the device.

In addition, a preferred solution is that the ammonia gas-flue gas mixer is disposed on the ammonia gas transmission pipeline of the dust removal and denitration integrated device, the ammonia gas inlet is connected to the ammonia gas outer line, and the flue gas inlet is connected through the ammonia gas dilution fan. Flue gas pipeline behind the fan.

In addition, a preferred solution is that the filter bag in the dust removal and denitration integrated device adopts pulse backflushing, and the compressed air pipe is connected to the compressed air unit; and the pyrolysis gas in the mixed pyrolysis regeneration section of the dust removal and denitration integrated device The conveying pipe is connected to the external gas hot blast stove.

In addition, a preferred solution is that the purification device further includes a public auxiliary system, wherein the public auxiliary system includes a compressed air unit and steam, a process water unit; compressed air in the compressed air unit, is used for filter bag pulse cleaning; steam, process The steam in the water unit is used to prepare the sodium-based desulfurizer solution and the circulating ash solution; the steam, the process water in the process water unit, the sodium-based desulfurizer solution and the circulating ash solution, and the cooling and anti-sulfurization system rinse.

Compared with the prior art, the beneficial effects of the present invention are:

1) Rotary spray drying desulfurization can effectively remove SO ₂ from flue gas, effectively prevent the formation of ammonium sulfate in the denitration section to block the catalyst; the desulfurization product is 50-100um dry particles, and the particulate matter enters the dust removal section from the desulfurization tower. On the outer surface of the dust filter bag, the filter bag is pre-sprayed, which can effectively adsorb viscous pollutants such as tar in the flue gas and protect the catalyst;

2) The sodium-based desulfurizing agent which is not completely reacted in the dust removal and desulfurization system is blocked from adhering to the outer surface of the filter bag, and continues to react with SO ₂ in the flue gas to further improve the desulfurization efficiency;

3) The dust removal and denitrification integrated equipment can filter and collect the desulfurization ash, and then re-feed it to the desulfurization tower after the second liquid distribution to realize the recycling of the desulfurization ash and improve the utilization rate of the sodium-based desulfurizer;

4) Efficient dust removal before denitrification, reducing the wear of dust on the denitration catalyst and prolonging the service life of the catalyst;

5) Integrate flue gas dedusting and denitrification, save one investment, reduce operating costs and reduce floor space;

6) Through the pressure equalization of the filter bag filter layer and the static pressure mixed layer, the flue gas velocity field and temperature field distribution are more uniform, and the denitration efficiency is further improved;

7) The system temperature is lowered, which can meet the requirements of the coking method. The coke oven chimney must always be in the hot standby state.

In order to achieve the above and related objects, one or more aspects of the present invention include the details which will be described later Features that are specified and particularly indicated in the claims. The following description and the annexed drawings set forth in detail However, these aspects are indicative of only some of the various ways in which the principles of the invention may be employed. Moreover, the invention is intended to include all such aspects and their equivalents

DRAWINGS

Other objects and results of the present invention will become more apparent and appreciated from the <RTIgt; In the drawings: FIG. 1 is a schematic flow chart of a coke oven flue gas desulfurization and denitration combined purification process according to an embodiment of the present invention;

2 is a schematic structural view of a coke oven flue gas desulfurization and denitration combined purification process according to an embodiment of the present invention.

In the figure: 1a. induced draft fan, 1b. wind electric control valve, 1c. air supply electric valve, 1d. flue gas pipeline, 2a. desulfurization tower, 2b. sodium-based desulfurizer solution preparation unit, 2c. circulating ash solution Preparation unit, 2d. solution delivery unit, 2e. flue gas distributor, 2f. top tank, 2g. atomizer, 3a. dust removal and denitrification integrated equipment, 3b. ammonia dilution fan, 3c. ammonia gas - flue Gas mixer, 3d. Desulfurization ash collection and transportation equipment, 3e. Gas hot air furnace, 3f. Filter bag purification function section, 3g. Mixed pyrolysis regeneration section, 3h. Denitration catalyst functional section, 4a. Compressed air unit, 4b. Steam , process water unit, 5. ammonia outside line, 6. coke oven flue, 7. coke oven chimney.

Detailed ways

In the following description, for the purposes of illustration However, it is apparent that these embodiments may be practiced without these specific details.

The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings:

In order to illustrate the coke oven flue gas desulfurization and denitration combined purification process provided by the present invention, FIG. 1 shows a coke oven flue gas desulfurization and denitration combined purification process according to an embodiment of the present invention.

As shown in FIG. 1 , the coke oven flue gas desulfurization and denitration combined purification process provided by the present invention comprises the following steps: S110: in the desulfurization system, the coke oven flue gas is subjected to rotary spray semi-dry method to reduce desulfurization at a low temperature;

S120: in the dust removal and denitration system, the particulate matter is subjected to dust filtration; and the selective catalytic reduction method is used to denitrate the coke oven flue gas which has undergone low temperature desulfurization and dust removal filtration in the dust removal and denitration integrated device;

S130: The flue gas after denitration is sent back to the coke oven flue, and is discharged through the coke oven chimney.

The above is the flow of the coke oven flue gas desulfurization and denitrification combined purification process, that is, before the flue gas denitration, the rotary spray semi-dry method is used to efficiently dehumidify and desulfurize, and then the residual ammonia produced by the coking plant steaming section is used or purchased. The ammonia vapor evaporated by the liquid ammonia is used as a reducing agent, and the denitration process is carried out by the selective catalytic reduction method. The denitration process is carried out in the integrated equipment for dust removal and denitration, and the particulate matter is removed by dust removal before denitration.

In order to explain the above process flow in detail, FIG. 2 shows the structure of the coke oven flue gas desulfurization and denitration combined purification process of the embodiment of the present invention.

As shown in FIG. 2, the coke oven flue gas desulfurization and denitration combined purification process of the present invention specifically comprises the following steps:

1) The coke oven flue gas is sucked from the coke oven flue 6 of the coke oven chimney 7 under the action of the induced draft fan 1a, and is transported into the desulfurization system through the flue gas pipeline 1d; the induced draft fan 1a is equipped with a variable frequency motor, The fan 1a performs frequency conversion speed regulation (may also use coupling speed regulation or permanent magnet speed regulation) and adjusts the wind electric control valve 1b on the flue gas duct 1d of the coke oven flue gas inlet end, which can ensure the normal production of the coke oven The required negative pressure value and the pressure value required for the normal operation of the desulfurization and dust removal and denitration system; that is, the fan is equipped with a variable frequency motor or a coupler or a permanent magnet governor, and the frequency converter is controlled by the frequency converter or the fluid coupling is used. Speed regulation or permanent magnet speed regulation mode to adjust the speed and adjust the wind electric control valve to provide the coke oven with the pressure required for the normal production of the coke oven, and meet the pressure requirements required for the normal operation of the desulfurization system and the dust removal and denitration system;

2) The desulfurization system is composed of a desulfurization tower 2a, a sodium-based desulfurizer solution preparation unit 2b, a circulating ash solution preparation unit 2c, and a solution delivery unit 2d, and the Na ₂ CO ₃ solution prepared by the sodium-based desulfurizer solution preparation unit 2b is transported through the solution. The unit 2d is sent to the top tank 2f at the top of the desulfurization tower 2a, and then the sodium-based desulfurizer solution flows into the atomizer 2g, and the atomizer 2g atomizes the sodium-based desulfurizer solution into 50-100 μm particles;

3) The flue gas stream of the coke oven is uniformly distributed in the desulfurization tower 2a through the flue gas distributor 2e at the top of the desulfurization tower 2a, and the coke oven flue gas and the atomized sodium-based desulfurizer particles are sufficiently contained in the desulfurization tower 2a. Mixing, SO ₂ reacts with sodium-based desulfurizer particles to form sodium sulfite and sodium sulfate, removes SO ₂ from the coke oven flue gas, and powdered sodium sulfite and sodium sulfate enters the dust removal and denitration system with the desulfurized flue gas. ;

4) The dust removal and denitration system is provided with a dust removal and denitrification integrated device 3a, an ammonia gas dilution fan 3b, an ammonia gas-flue gas mixer 3c and a desulfurization ash collection and transportation device 3d; the flue gas first enters the dust removal and denitration integrated device 3a. The bag purifying function section 3f, the dust in the flue gas is blocked outside the filter bag and attached to the surface of the filter bag, and the pressure equalization effect of the filter bag resistance layer makes the flue gas uniformly distributed on the cross section of the filter layer;

5) The filtered flue gas through 3g mixing ammonia gas is mixed with the pyrolysis of sprayed into the regeneration zone and then enters the denitration catalyst functional segments 3h, NO _x in the flue gas is reduced in ammonia denitration catalyst into N ₂ ;

6) After the dust removal and denitration, the flue gas flows out from the top of the dust removal and denitration integrated device 3a, and is sent back to the coke oven flue 6 through the induced draft fan 1a and the air supply electric valve 1c, and is discharged through the coke oven chimney 7;

7) The particulate matter in the flue gas filtered in the dedusting and denitrification integrated device 3a and the reactant generated by the desulfurization are transported to the circulating ash solution preparation unit 2c in the desulfurization system through the desulfurization ash collection and transport device 3d, and are configured into a cycle. The ash solution is then sent to the top tank 2f at the top of the desulfurization tower 2a via the solution transport unit 2d to participate in the coke oven flue gas desulfurization process, so that the unreacted sodium-based desulfurizing agent is fully utilized.

In the dust removal and denitration system, the residual ammonia water generated from the steaming plant of the coking plant or the ammonia vapor evaporated by the purchased liquid ammonia is mixed with the purified flue gas extracted by the ammonia dilution fan 3b in the ammonia gas-flue gas mixer 3c. After dilution, it is sent to the dust removal and denitration integrated device 3a for denitration reaction.

The gas hot blast stove 3e periodically sends the high temperature pyrolysis gas to the mixed pyrolysis regeneration section 3g in the dust removal and denitration integrated equipment 3a to promote the regeneration of the denitration catalyst.

It is used to realize a coke oven flue gas desulfurization and denitration combined purification device, comprising a desulfurization tower 2a and a dust removal and denitrification integrated device 3a, and a dust removal and denitration integrated device 3a is provided with a filter bag purification function section 3f from the bottom to the top, and a mixed pyrolysis The regeneration section 3g and the denitration catalyst functional section 3h; the flue gas pipeline 1d drawn from the coke oven flue 6 is sequentially connected to the desulfurization tower 2a and the dust removal and denitration integrated equipment 3a to form a flue gas circulation purification system, and the dust removal and denitration integrated equipment 3a is connected. The flue gas duct 1d of the coke oven flue 6 is provided with an induced draft fan 1a equipped with a variable frequency motor; the atomizer 2g at the top of the desulfurization tower 2a is connected with the top tank 2f, and the sodium-based desulfurizer solution is respectively connected through the solution transport unit 2d. The preparation unit 2b and the circulating ash solution preparation unit 2c, the circulating ash solution preparation unit 2c is connected to the bottom ash silo of the dust removal and denitration integrated device 3a through the desulfurization ash collection and transport device 3d.

Specifically, in the embodiment of the present invention, the filter bag purifying function section 3f in the dust removal and denitration integrated device includes a ash silo, a closed ash discharge valve, a flue gas inlet, a gas flow uniform baffle, a filter bag, and a pulse spray. Blowing device; the ash bin is located below the filter bag purifying function section of the dust removal and denitrification integrated equipment, and the closed ash discharging valve is installed at the ash silo discharge port; the flue gas inlet is arranged at the upper side of the desulfurizing dust collecting and purifying filter bag purifying function section On the wall, the multi-row filter bags are vertically embedded in the flower plate holes, and are evenly distributed along the longitudinal direction. The air flow uniform baffles are disposed between the flue gas inlet and the filter bag, and the upper part of the filter bag is provided with a pulse blowing device. Among them, the ash silo is used to collect and store the particulate matter separated from the flue gas. One function of the closed ash discharge valve is to prevent the outside air from penetrating into the device through the discharge port to reduce the temperature of the flue gas, and the other function is to discharge the ash silo. Dust particles collected.

The upper part of the filter bag purifying function section 3f includes a flue gas inlet, a gas flow uniform baffle, a filter bag, and a pulse blowing device. The flue gas inlet is arranged on the side tower body above the filter bag purifying function section, and the multi-row filter bag is vertically embedded in the filter bag purifying function segment flower plate hole, and is evenly distributed along the longitudinal direction, and the airflow uniform baffle is arranged at Between the flue gas inlet and the filter bag. The airflow uniform baffle is a labyrinth structure composed of angled steel plates, which can coarsely separate the coarse pulverized coal powder contained in the dust gas, and at the same time conduct diversion of the dusty flue gas to make the airflow distribution on the surface of the filter bag uniform and avoid The dust-containing gas directly washes the surface of the filter bag, which affects the efficiency and service life of the filter bag. The pulse blowing device is arranged in the clean air area of the upper part of the filter bag for pulse backflushing and cleaning the filter bag.

The mixed pyrolysis regeneration section 3g includes an ammonia spray structure, a pyrolysis gas transport injection structure, and a mixed current sharing structure. The pyrolysis gas conveying injection structure body is composed of a plurality of air supply ducts arranged in parallel, and each air supply duct is provided with an air volume regulating valve, and the air supply ducts are arranged on the air supply ducts in the tower; the ammonia spray structure is arranged Above the pyrolysis gas conveying injection structure, a plurality of parallel spraying ammonia pipelines are arranged, each of the ammonia spraying pipelines is provided with an ammonia spraying regulating valve, and the ammonia spraying pipeline is uniformly distributed with an ammonia injection port; the mixed current sharing structure It is arranged above the ammonia spraying structure, and is composed of 1 to 4 layers of porous plates having an arc-shaped corrugation or an angular corrugation shape, and the adjacent two layers are staggered at an angle of 90° in the corrugation direction. In addition, the denitration catalyst functional section 3h includes a denitration catalyst and a purified flue gas outlet, the denitration catalyst is arranged in layers 2 to 4, and the purified flue gas outlet is disposed at the top of the dust removal and denitration integrated device.

A wind electric control valve 1b is arranged on the flue gas duct 1d between the coke oven flue 6 and the desulfurization tower 2a, and a flue gas electric valve is arranged on the flue gas duct 1d between the draft fan 1a and the coke oven flue 6. 1c.

The ammonia gas transmission pipe of the dust removal and denitration integrated device 3a is provided with an ammonia gas-flue gas mixer 3c, the ammonia gas inlet of the ammonia gas-flue gas mixer 3c is connected to the ammonia gas outer line 5, and the flue gas inlet is passed through the ammonia gas. The dilution fan 3b is connected to the flue gas duct 1d (in the direction of flue gas transport) after the draft fan 1a.

The sodium-based desulfurizing agent solution preparation unit 2b and the circulating ash solution preparation unit 2c are additionally connected to the steam, process water unit 4b.

A flue gas distributor 2e is provided at the top of the desulfurization tower 2a.

The filter bag in the dust removal and denitrification integrated device 3a adopts pulse backflushing and cleaning, and the compressed air pipe is connected to the external compressed air unit 4a; the pyrolysis gas delivery pipe in the mixed pyrolysis regeneration section 3g of the dust removal and denitration integrated device is connected to the external Gas hot blast stove 3e.

Based on the specific process flow of the above-mentioned coke oven flue gas desulfurization and denitrification combined purification, the present invention also provides a coke oven flue gas desulfurization and denitration combined purification device including an air intake system, a desulfurization system, a dust removal and denitration system, and a public auxiliary system, a coke oven Flue gas circulation purification, coke oven flue gas flow path is coke oven flue 6 → desulfurization tower 2a → dust removal and denitrification integrated equipment 3a → induced draft fan 1a → coke oven flue 6 → coke oven chimney 7 → outer row.

The air intake system includes a flue gas duct 1d, an induced draft fan 1a disposed on the flue gas duct 1d, a wind electric control valve 1b, and a blower electric valve 1c for attracting and returning the coke oven flue gas, which is a coke oven The flue gas circulation purification provides power; the induced draft fan 1a is installed at the end of the coke oven flue gas circulation purification system, and the desulfurization tower 2a and the dust removal and denitration integrated device 3a are in a negative pressure operation state. The induced draft fan 1a is equipped with a variable frequency motor or a coupler or a permanent magnet governor. By adjusting the induced draft fan 1a and adjusting the take-up electric control valve 1b, the negative pressure value required for the normal production of the coke oven can be ensured. The pressure value required for the normal operation of the desulfurization and dedusting and denitration system.

The desulfurization system comprises a desulfurization tower 2a, a sodium-based desulfurizer solution preparation unit 2b, a circulating ash solution preparation unit 2c and a solution delivery unit 2d for removing SO ₂ from the coke oven flue gas; the desulfurization tower 2a is provided with a coke oven smoke The gas inlet, the atomizer 2g, the top tank 2f and the flue gas distributor 2e, the liquid outlet of the top tank 2f is connected to the atomizer 2g, the liquid inlet is connected to the sodium-based desulfurizer solution preparation unit 2b, and the circulating ash solution is prepared. Unit 2c.

The sodium-based desulfurizer solution preparation unit 2b is provided with a sodium-based desulfurizer storage bin, a variable frequency discharge valve, a weighing feeder, a liquid distribution tank, a solution tank, and a heating water tank for preparing a certain concentration of sodium-based desulfurizer solution. Used for desulfurization of coke oven flue gas. The circulating ash solution preparation unit 2c is provided with a desulfurization ash silo, a frequency conversion discharge valve, a fixed frequency discharge valve, a weighing feeder, and a circulating ash solution tank for formulating the collected desulfurization ash into a solution. The sodium-based desulfurizing agent is reused and then discharged. The solution conveying unit 2d is provided with a sodium-based desulfurizing agent solution pump, a circulating ash solution pump, a solution conveying pipe, and a valve for conveying the formulated sodium-based desulfurizing agent solution and the circulating ash solution to the top tank 2f at the top of the desulfurization tower 2a. .

The lower part of the desulfurization tower 2a is provided with a flue gas outlet, the bottom is provided with a cone ash hopper, and the ash hopper outlet is provided with a lock gas discharge valve; the desulfurization ash collection and transportation equipment 3d comprises a scraper and a bucket lifter for dedusting and denitrification. The desulfurized ash discharged from the chemical plant 2a is sent to the circulating ash solution preparation unit 2c of the desulfurization system.

The dust removal and denitration system includes dust removal and denitrification integrated equipment 3a, ammonia dilution fan 3b, ammonia gas-flue gas mixer 3c, desulfurization ash collection and transportation equipment 3d and gas hot air furnace 3e; flue gas after desulfurization is integrated in dust removal and denitration the first filter unit 3a dust, and then mixed with the diluted ammonia gas, into the catalyst layer; NO _X in the flue gas is reacted with ammonia over a catalyst, NO _X is reduced to produce nitrogen gas.

The dust removal and denitrification integrated device 3a has a particulate matter purifying function, and the flue gas first contacts the filter bag to prevent the dust from entering the denitration layer, and at the same time, the uniform pressure of the filter bag resistance layer is used to realize the uniform distribution of the flue gas on the cross section of the filter layer; The unreacted sodium-based desulfurizing agent is blocked from adhering to the outer surface of the filter bag, and continues to react with SO ₂ in the flue gas to further improve the desulfurization efficiency.

The public auxiliary system includes a compressed air unit 4a and steam, a process water unit 4b, compressed air for filter bag pulse cleaning, steam and process water for formulating a sodium-based desulfurizer solution and a circulating ash solution; and part of the process water for the desulfurization system Cooling and backwashing.

The coke oven flue gas desulfurization and denitration combined purification device and the flue gas pipeline provided by the invention are provided with thermal insulation materials to ensure the system temperature is lowered, and the temperature requirements of the coke oven chimney 7 are discharged.

It can be seen from the above embodiments that the coke oven flue gas desulfurization and denitration combined purification process and device provided by the invention combines desulfurization by rotary spray drying with desulfurization of low temperature SCR to realize high-efficiency desulfurization and denitrification of the flue gas of the coke oven. The process is simple, the floor space is small, and the equipment investment is small.

The coke oven flue gas desulfurization and denitration combined purification process and apparatus according to the present invention are described above by way of example with reference to the accompanying drawings. However, it should be understood by those skilled in the art that various improvements can be made to the coke oven flue gas desulfurization and denitration combined purification process and apparatus proposed by the present invention without departing from the scope of the present invention. Therefore, the scope of the invention should be determined by the content of the appended claims.

Claims (20)

1. A coke oven flue gas desulfurization and denitration combined purification process comprises the following steps:

   In the desulfurization system, the coke oven flue gas is subjected to rotary spray semi-dry method to reduce desulfurization at a low temperature;

   In the dust removal and denitration system, the particulate matter is subjected to dust filtration; and the selective catalytic reduction method is used to denitrate the coke oven flue gas which has undergone low temperature desulfurization and dust removal filtration in the dust removal and denitration integrated device;

   The flue gas after denitration is sent back to the coke oven flue and discharged through the coke oven chimney.
2. The coke oven flue gas desulfurization and denitration combined purification process according to claim 1, wherein the rotary spray semi-dry process low temperature desulfurization process comprises:

   The coke oven flue gas is sucked out from the coke oven flue at the root of the coke oven chimney by the induced draft fan, and is transported into the desulfurization system through the flue gas pipeline; wherein the desulfurization system is prepared by a desulfurization tower and a sodium-based desulfurizer solution preparation unit. , a circulating ash solution preparation unit and a solution delivery unit;

   In the desulfurization system, the sodium-based desulfurizer solution delivered to the top tank of the desulfurization tower through the solution transport unit is atomized into a sodium-based desulfurizer particle of 50-100 μm by an atomizer;

   The coke oven flue gas stream is evenly distributed in the desulfurization tower through a flue gas distributor at the top of the desulfurization tower, and the atomized sodium-based desulfurizer particles are fully reacted in the desulfurization tower to form sodium sulfite and Sodium sulfate is used to remove SO ₂ from the flue gas of the coke oven, and the flue gas of the sodium sulfite desulfurization with the flue gas of the coke oven enters the dust removal and denitration system.
3. The coke oven flue gas desulfurization and denitration combined purification process according to claim 2, wherein the process of dust removal and filtration of the particulate matter comprises:

   The dust removal and denitration system is provided with a dust filter bag and a desulfurization ash collection and transportation device. The flue gas first enters the filter bag purification function section of the dust removal and denitration integrated device, and the dust in the flue gas is blocked outside the filter bag and attached to the filter bag. The surface of the filter bag, while the pressure equalization of the filter bag resistance layer, allows the flue gas to be evenly distributed across the cross section of the filter layer.
4. The coke oven flue gas desulfurization and denitration combined purification process according to claim 1, wherein the process of denitrification of the coke oven flue gas subjected to low temperature desulfurization and dust removal filtration by the selective catalytic reduction method comprises :

   The filtered flue gas through a regenerative pyrolysis mixing section mixing with the injected ammonia, before entering the denitration catalyst functional segments, NO _x in the flue gas is reduced to N ₂ in the ammonia catalyst denitration.
5. The coke oven flue gas desulfurization and denitration combined purification process according to claim 3, wherein

   The particulate matter in the flue gas filtered in the dust removal and denitration integrated device and the reactant formed by the desulfurization are transported to the circulating ash solution preparation unit through the desulfurization ash collection and conveying device, and are formulated into a circulating ash solution. The top tank which is sent to the top of the desulfurization tower through the solution conveying unit participates in the desulfurization process of the coke oven flue gas, so that the unreacted sodium-based desulfurizing agent is fully utilized.
6. The coke oven flue gas desulfurization and denitration combined purification process according to claim 3, wherein in the dust removal and denitration system, ammonia gas is extracted in the ammonia gas-flue gas mixer and the ammonia gas dilution fan After the purification, the flue gas is mixed and diluted, and then sent to the dust removal and denitration integrated device for denitration reaction.
7. The coke oven flue gas desulfurization and denitration combined purification process according to claim 3, wherein the gas hot blast stove periodically sends the high temperature pyrolysis gas to the mixed pyrolysis regeneration section in the dust removal and denitration integrated device. Promote regeneration of the denitration catalyst.
8. The utility model relates to a coke oven flue gas desulfurization and denitration combined purification device, which comprises: an air introduction system, a desulfurization system and a dust removal and denitration system, wherein

   The air guiding system is configured to attract and return the coke oven flue gas to provide power for the coke oven flue gas circulation purification;

   The desulfurization system is used for removing SO ₂ from the flue gas of the coke oven;

   The dust removal and denitration system is used for dedusting the flue gas after desulfurization, and then denitrifying the flue gas after dedusting.
9. The coke oven flue gas desulfurization and denitration combined purification device according to claim 8, wherein

   The air guiding system includes a flue gas duct, an induced draft fan disposed on the flue gas duct, and a wind electric regulating valve disposed on the flue gas duct between the coke oven flue and the desulfurization tower, and is disposed at a blower electric valve on the flue gas duct between the induced draft fan and the coke oven flue; wherein

   The induced draft fan is equipped with a variable frequency motor or a coupler or a permanent magnet governor, and provides normal operation for the desulfurization system and the dust removal and denitration system by adjusting the induced draft fan and adjusting the air intake electric regulating valve. The pressure required.
10. The coke oven flue gas desulfurization and denitration combined purification device according to claim 8, wherein

    The desulfurization system includes a desulfurization tower, a sodium-based desulfurizer solution preparation unit, a circulating ash solution preparation unit, and a solution delivery unit; wherein

    Providing a coke oven flue gas inlet, an atomizer, a top tank and a flue gas distributor at a top of the desulfurization tower, and connecting the atomizer to a liquid outlet of the top tank, the top tank The liquid inlet is connected to the sodium-based desulfurizer solution preparation unit and the circulating ash solution preparation unit.
11. The coke oven flue gas desulfurization and denitration combined purification device according to claim 10, wherein

    The sodium-based desulfurizer solution preparation unit includes a sodium-based desulfurizer storage tank, a variable frequency discharge valve, a weighing feeder, a liquid distribution tank, a solution tank, and a heating water tank;

    It is used to prepare sodium-based desulfurizer solution for desulfurization of coke oven flue gas.
12. The coke oven flue gas desulfurization and denitration combined purification device according to claim 10, wherein

    The circulating ash solution preparation unit comprises a desulfurization ash silo, a variable frequency discharge valve, a fixed frequency discharge valve, a weighing feeder, a circulating ash solution tank; and, for formulating the collected desulfurization ash into a solution, and recycling the same The sodium-based desulfurizing agent is then discharged.
13. The coke oven flue gas desulfurization and denitration combined purification device according to claim 10, wherein

    The solution delivery unit includes a sodium-based desulfurizer solution pump, a circulating ash solution pump and a solution delivery conduit, and a valve; and is configured to deliver the formulated sodium-based desulfurizer solution and the circulating ash solution to the top tank.
14. The coke oven flue gas desulfurization and denitration combined purification device according to claim 10, wherein

    The dust removal and denitration system comprises an integrated dust removal and denitration device, an ammonia dilution fan, an ammonia gas-flue gas mixer and a desulfurization ash collection and transportation device;

    The dust removal and denitration integrated device comprises a filter bag purification function section, a mixed pyrolysis regeneration section and a denitration catalyst functional section from bottom to top;

    a flue gas pipeline leading from the coke oven flue is connected to the desulfurization tower and the dust removal and denitration integrated device in sequence; the dust removal and denitration integrated device is connected to the induced draft fan; and the atomizer at the top of the desulfurization tower is connected with the top tank And connecting, by the solution transport unit, the sodium-based desulfurizer solution preparation unit and the circulating ash solution preparation unit, respectively, the circulating ash solution preparation unit passes through the desulfurization ash collection and transportation device Connect the bottom ash bin of the dust removal and denitrification integrated equipment.
15. The coke oven flue gas desulfurization and denitration combined purification device according to claim 14, wherein

    The filter bag purification function section comprises a ash silo, a closed ash discharge valve, a flue gas inlet, a gas flow uniform baffle, a filter bag and a pulse blowing device; wherein

    The ash silo is disposed under the dust removal and denitration integrated device, the sealed ash discharge valve is disposed at a ash discharge port, and the flue gas inlet is disposed on a sidewall of the upper portion of the filter bag purification function section The filter bag is vertically embedded in the flower plate hole and is evenly distributed in the longitudinal direction, and the airflow uniform baffle is disposed between the flue gas inlet and the filter bag, and the filter bag is provided with a pulse spray Blowing device.
16. The coke oven flue gas desulfurization and denitration combined purification device according to claim 14, wherein

    The mixed pyrolysis regeneration section includes an ammonia spray structure, a pyrolysis gas transport injection structure, and a mixed current sharing structure; wherein

    The pyrolysis gas delivery injection structure comprises a plurality of air supply ducts arranged in parallel, each air supply duct is provided with an air volume regulating valve, and the air supply duct of the orifice plate is evenly distributed on the air supply duct of the desulfurization tower;

    The ammonia spraying structure is disposed above the pyrolysis gas conveying injection structure body, and comprises a plurality of parallel spraying ammonia pipelines, each of which has an ammonia spraying regulating valve, and the ammonia spraying pipeline is uniformly distributed with ammonia. Jet port

    The mixed current sharing structure is disposed above the ammonia spraying structure, and is composed of 1 to 4 layers of porous plates having a curved corrugation or an angular corrugation shape, and the adjacent two layers are separated by a 90° angle according to the corrugation direction. Staggered.
17. The coke oven flue gas desulfurization and denitration combined purification device according to claim 14, wherein

    The denitration catalyst functional section includes a denitration catalyst and a purification flue gas outlet, the denitration catalyst is disposed in a layer of 2 to 4, and the purified flue gas outlet is disposed at the top of the desulfurization tower.
18. The coke oven flue gas desulfurization and denitration combined purification device according to claim 14, wherein

    The ammonia gas-flue gas mixer is disposed on the ammonia gas transmission pipeline of the dust removal and denitration integrated device, the ammonia gas inlet is connected to the ammonia gas outer line, and the flue gas inlet is connected to the induced draft fan through the ammonia gas dilution fan. Flue gas pipeline.
19. The coke oven flue gas desulfurization and denitration combined purification device according to claim 14, wherein

    The filter bag in the dust removal and denitration integrated device adopts pulse back-blowing cleaning, and the compressed air pipe is connected to the compressed air unit;

    The pyrolysis gas delivery pipe in the mixed pyrolysis regeneration section of the dust removal and denitration integrated device is connected to an external gas hot air furnace.
20. The coke oven flue gas desulfurization and denitration combined purification device according to claim 19, further comprising a public auxiliary system, wherein

    The public auxiliary system includes the compressed air unit and steam, and a process water unit;

    The compressed air in the compressed air unit is used for pulse cleaning of the filter bag;

    The steam, the steam in the process water unit, is used to prepare a sodium-based desulfurizer solution and a circulating ash solution; the steam, the process water in the process water unit, is used to prepare a sodium-based desulfurizer solution and a circulating ash solution, and The desulfurization system is cooled and backwashed.

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