CN116371192A - Coke oven flue gas integrated purification and byproduct recycling system and process - Google Patents

Abstract

The invention discloses a coke oven flue gas integrated purification and byproduct recycling process which comprises the following steps: the coke oven flue gas is subjected to dust removal and then is regulated to 200+/-20 ℃, is sent into a GGH heat exchanger, is cooled to 120-140 ℃, is sent into a desulfurization and denitrification integrated purification tower from the lower part, is subjected to countercurrent contact with ammonia water to remove sulfur oxides, partial nitrogen oxides and particulate matters, is subjected to photooxidation demisting, dust removal and purification section to remove free water, and simultaneously removes sulfur oxides, nitrogen oxides, ammonia salts and the like, the temperature of the flue gas at the outlet of the purification tower is 50-70 ℃, is increased to 120+/-20 ℃ through the GGH heat exchanger, and enters the dry process integrated purification tower to carry out desulfurization, denitrification, dioxin removal and heavy metal removal and dust removal, and is discharged. The integrated purified active coke is recycled for 4 to 10 times, and the active carbon or the active coke is manufactured by water washing, alkali washing and deep activation; the byproducts such as dust removal, undersize and the like generated during the cyclic regeneration and the deep activation are used for preparing a water treatment agent or preparing a soil conditioner by compounding with desulfurization byproducts.

Description

A coke oven flue gas integrated purification and by-product resource utilization system and process

technical field

The invention relates to the technical field of flue gas treatment and purification, in particular to a coke oven flue gas integrated purification and by-product resource utilization system and process.

Background technique

Ammonia flue gas desulfurization technology is one of the most commonly used desulfurization methods in coking. This process can not only desulfurize efficiently but also remove some nitrogen oxides. The by-product is ammonium sulfate, which realizes resource recovery and utilization. It is the most effective and environmentally friendly wet flue gas desulfurization technology for controlling acid rain and sulfur dioxide pollution. The ammonia-based flue gas desulfurization process is generally divided into three major steps: desulfurization absorption, intermediate product treatment, and by-product manufacturing. According to the different processes and by-products, it can be divided into ammonia-fertilizer method, ammonia-acid method, ammonia-ammonium sulfite method, etc. However, the existing ammonia process itself has the problem of ammonia escape; and the ammonia process is a wet desulfurization process, and the problem of white smoke at the outlet exists; Smoke cannot be discharged through the original chimney. Ammonia desulfurization alone will cause corrosion to the chimney because the outlet temperature is too low and the water content is too high. If the temperature of the chimney is too low, the suction will be insufficient and smoke cannot be discharged normally. Therefore, the ammonia desulfurization of the prior art is usually a self-supporting chimney, the chimney is fed with hot air for thermal backup, and the system has two outlets.

The activated coke flue gas desulfurization and denitrification integrated purification process is also widely used. It has the integration of desulfurization and denitrification, no white smoke and rain, and removes harmful substances such as dioxins and heavy metals while desulfurization and denitrification. However, the desulfurization process requires more active coke Therefore, the desulfurization system must be equipped with a regenerated active coke system as a supporting system. The regeneration system consumes a lot of energy, and the regenerated active coke cannot be regenerated indefinitely, and the saturated activated coke that has reached the number of regenerations cannot be used as a resource.

Contents of the invention

The purpose of the present invention is to provide a coke oven flue gas integrated purification and by-product resource utilization system and process.

In order to achieve the above object, the technical scheme adopted in the present invention is specifically as follows:

A coke oven flue gas integrated purification and by-product resource utilization process, specifically:

After the coke oven flue gas is dedusted by the dust removal equipment, the temperature is adjusted to 200±20°C by the temperature adjustment equipment, and the flue gas is pressurized to 7500±500Pa by the booster fan, and the coke oven flue gas is sent to the hot side inlet of the GGH heat exchanger , the temperature of the flue gas at the hot side outlet of the GGH heat exchanger drops to 120-140°C, and it is sent to the desulfurization and denitrification integrated purification tower, where the flue gas is in countercurrent contact with ammonia water to remove sulfur dioxide and part of the nitrogen in the flue gas Oxide and particulate matter; after flue gas desulfurization, the temperature is reduced to 50-70°C, and the free water, sulfur oxides, and nitrogen oxides in the flue gas are further eliminated by passing through the photo-oxygen demisting and dust-removing purification section on the top of the desulfurization and denitrification integrated purification tower. Remove; after the flue gas enters the GGH heat exchanger again for heat exchange, the temperature rises from 50-70°C to 120±20°C, and after the ammonia water is sprayed into the flue gas through the atomizer in the ammonia injection section, the flue gas enters the dry integration The purification tower removes sulfur dioxide, nitrogen oxides, particulate matter, dioxins, and heavy metals in the flue gas; the purified flue gas is discharged into the chimney.

The by-products of the system are the concentrated ammonium sulfate solution discharged from the desulfurization and denitrification integrated purification tower, and the saturated activated coke discharged from the dry integrated purification tower; Coal blending in the coking plant to produce coke; saturated activated coke particles need to be sieved after regeneration, and the regenerated activated coke particles reaching the particle size are sent back to the dry process integrated purification tower for recycling; the undersieve is combined with concentrated ammonium sulfate solution to prepare soil conditioner ; The saturated active coke is regenerated and recycled to prepare high-performance activated coke and activated carbon products.

Wherein, the photo-oxygen demisting and dust-removing purification section is equipped with a high-efficiency fog-removing and dust-removing system and a photo-oxygen catalytic oxidation system.

Specific layout (from bottom to top): 2-layer plate demister + 1-layer tube bundle turbulent demister + wet electronic precipitator (WESP) + photo-oxygen catalytic oxidation system (UV light source + reaction tray + nanomaterial + BAC) , Each floor is equipped with a spray flushing system (for flushing the mist eliminator or dust collector).

When working, the flue gas first passes through the 2-layer plate demister to remove most of the large liquid droplets and dust with a large diameter, and then passes through the tube bundle turbulent flow demister to remove most of the small liquid droplets and dust with a small diameter. WESP wet electronic precipitator removes tiny liquid droplets and smoke in the flue gas;

The photo-oxygen catalytic oxidation system is specifically composed of reaction trays, nanomaterials, UV light sources, _H2O2 injection systems, _BAC layers, and flushing spray systems; both the front and back of the reaction trays are coated with nanomaterials; among them, WESP The top of the wet electronic precipitator is sprayed with nano-materials, and a _UV light source is set on the upper part of the _WESP wet electronic precipitator. Set up the BAC layer;

When working, the UV light source irradiates the nanomaterials on _both sides of the reaction tray _to generate free hydroxyl groups (OH) and active oxygen (O ₂ ^- ) with strong oxidizing ability. When the gas passes through the photo-oxygen catalytic oxidation system, a photocatalytic oxidation reaction occurs, so that SO _X and NOx are oxidized to SO ₄ ^2- and NO ₃ ^- , and after being washed by the spray flushing system, sulfate and nitrate are formed and fall to the bottom of the desulfurization tower. The BAC layer set on the top of the photo-oxygen catalytic oxidation reaction section, through the combined structure and effect of biological activated carbon (BAC) adsorption enrichment, water film capture and biochemical decomposition, prevents O ₃ from escaping and polluting the environment on the one hand, and adsorbs on the other hand , Decompose SO _x , NO _x and other pollutant components in flue gas.

Wherein, when the desulfurization and denitrification integrated purification tower is applied in a coking plant, the ammonia distillation condensate in the ammonia distillation section of the plant can be used for desulfurization.

Wherein, the desulfurization product of the desulfurization and denitrification integrated purification tower-ammonium sulfate solution is used to prepare the soil conditioner.

Wherein, after the coke oven flue gas is led out from the underground flue, if the dust content of the flue gas exceeds 100 mg/Nm ³ , additional dust removal equipment is required for dust removal.

Wherein, the flue gas temperature at the outlet of the temperature adjustment equipment is 200±20°C, which can be realized by means of a waste heat boiler, an air cooler, and a water cooler alone or in combination.

Wherein, the photo-oxygen defogging and dust-removing purification section can remove 20-40% of nitrogen oxides.

The coke oven flue gas integrated purification and by-product resource utilization system adopted in the process of the present invention includes successively connected dust removal equipment, temperature adjustment equipment, booster fan, GGH heat exchanger and desulfurization and denitrification integrated purification tower. The top of the tower is equipped with a photooxygen demist and dust removal section, the outlet of the photooxygen demist and dust removal section is connected to the GGH heat exchanger, and the GGH heat exchanger is followed by an ammonia spray section and a dry integration purification tower.

Wherein, the inlet temperature of the desulfurization and denitrification integrated purification tower is 120-140°C, wherein the flow velocity of the desulfurization section (i.e. the lower half of the desulfurization and denitrification integrated purification tower, that is, the lower half of the tower body below the variable diameter) is 3m/s , the flow velocity of the photo-oxygen defogging and dust removal purification section is 2m/s; the pH of the liquid at the bottom of the desulfurization section is 6.5-7.5; the density of the ammonium sulfate solution and ammonia water solution at the bottom of the desulfurization section is 1.03-1.08mg/cm ³ . When the density is greater than 1.08, turn on the discharge pump to discharge the ammonium sulfite solution, and when the density is less than or equal to 1.03, stop the discharge pump.

Wherein, the inlet temperature of the dry-process integrated purification tower is 120±20° C., and the gas velocity in the dry-process integrated purification tower is 0.2-0.3 m/s.

Among them, the saturated activated coke discharged from the dry integrated purification tower is transferred to the regeneration converter, and the regeneration converter is heated to 300-400°C, and steam is introduced at a pressure of 2-3 bar for regeneration. The activated coke is decomposed, and the active coke is regenerated, and the regenerated active coke is sent back to the dry integrated purification tower for continued use. The underscreen and dust can be used to prepare soil improvers. The regeneration process can be cycled up to 7 times; It is sent to the front end of the dust removal equipment, and after heat exchange, it enters the ammonia desulfurization and denitrification integrated tower and the dry integrated purification tower for purification and discharge.

Among them, when the activated coke deacidifies and purifies the flue gas in the dry integrated purification tower, the deacidified products H ₂ SO ₄ , HNO ₃ , HCl, HF, etc. dissolve the ash in the activated coke, and combine with the moisture in the flue gas to produce erosion and pore formation function, forming new pores and channels, expanding the specific surface area, and enriching the functional groups of active coke. After repeated adsorption-etching-desorption for 4 to 10 times through the use and regeneration cycle of the dry-process integrated purification tower and regeneration converter, the saturated active coke discharged from the dry-process integrated purification tower is washed and soaked for 1 to 2 hours to dissolve the After the acidic component, it is washed and soaked with 5% ammonia water for 0.5 hours, then washed with fresh running water until the pH of the effluent is between 8 and 9, then transported to the activation furnace, and activated at 900 to 1150 ° C in the activation furnace to obtain High-performance activated coke or activated carbon; the high-temperature tail gas generated during the regeneration and activation of activated coke and activated carbon can be sent to the front end of the dust removal equipment, and after heat exchange, it enters the ammonia desulfurization and denitrification integrated tower and the dry integrated purification tower for purification and discharge; the second The water in the second washing process is weakly alkaline water, which can be reused in the first washing process to neutralize the acidic substances adsorbed in the active coke; the wastewater from alkali washing and first washing is sent to the water treatment section for purification.

Process principle of the present invention:

(1) Desulfurization and denitrification integrated purification tower

On the basis of the traditional ammonia desulfurization tower, the present invention couples the photo-oxygen demist and dust removal purification section. Through transformation, the traditional ammonia desulfurization tower has a certain denitrification ability while improving the demist and dust removal ability. Under the condition of low oxides, the outlet index can directly meet the emission requirements, the system transformation period is short, the land occupation is small, and the investment is low. In the photo-oxygen demisting and dedusting purification section, WESP (wet electronic precipitator), TBS (rotary sink coupling) and photocatalytic oxidation section (or BAC section) are combined through the rational layout of the space to achieve the use of the smallest space to complete the dedusting Fog, dust removal, and denitrification capabilities.

Among them, TBS (rotary sink coupling) mainly refers to the 1-layer tube bundle turbulent flow demister, which uses the principle of rotary sink coupling to increase the efficiency of dust removal and mist removal.

(2) Coking industry ammonia desulfurization and activated coke denitrification resource integration process

The ammonia distillation section of the coking industry can provide about 10% ammonia water for desulfurization, and the products of ammonia desulfurization can be sent to the ammonium sulfate section of the coking plant to refine ammonium sulfate after treatment. The invention uses a GGH heat exchanger to reheat the flue gas at the desulfurization outlet with the high-temperature flue gas at the desulfurization inlet, raise the temperature of the flue gas to 120±20°C, and then send it to a dry-process integrated purification tower for denitrification of the flue gas. In this denitrification process, the reaction is a reduction reaction, and it is necessary to supplement the reducing agent—ammonia water. After the combination of ammonia desulfurization and activated coke denitrification process, the escaped ammonia from ammonia desulfurization can be used as part of the ammonia source for activated coke denitrification, which solves the problem of ammonia escape. problems, and reduces external supplemental ammonia sources. The system uses a desulfurization and denitrification integrated purification tower to effectively control the dust content in the flue gas, and through the temperature adjustment of the GGH, the purpose of flue gas whitening and return to the chimney emission is achieved. The denitrification tower simultaneously removes dioxins and heavy metals in the flue gas while denitrifying.

(3) Active coke regeneration process

In this active coke regeneration process, due to the ammonia desulfurization at the front, the saturation rate of the active coke is greatly reduced during the denitrification process, providing sufficient production time for regeneration, and the saturated active coke discharged from the dry integrated purification tower can be operated to regeneration Furnace, the temperature is 300℃～400℃, and 2～3bar steam is introduced for regeneration. It can also be washed with water to dissolve the acidic substances in the surface layer and the interior of the void, and then transported to the regeneration converter through the system, and the temperature is 900～1150℃ for regeneration and activation. High performance active coke.

The high-temperature tail gas generated by the regeneration of activated coke can be sent to the front end of the GGH heat exchanger, and after heat exchange, it enters the ammonia desulfurization and denitrification integrated tower and the dry integrated purification tower for purification and discharge.

(4) High-performance active coke manufacturing process

In this high-performance active coke manufacturing process, the active coke discharged from the dry-process integrated purification tower is adsorbed and saturated in the process of desulfurization and denitrification, and a large amount of acidic substances are adsorbed inside. The surface and internal pores are corroded by acidic substances, and the active coke will be more efficient There are many pores and active sites to improve the adsorption capacity of activated coke. It is necessary to dissolve the acidic substances in the surface layer of the active coke and the inside of the gap by washing with water. The active sites on the surface of the active coke are exposed more, which can improve its catalytic activity; Then increase the basic groups on its surface through alkali washing. In this process, ammonia water can be added to increase the basic groups of active coke, enhance its desulfurization and denitrification effects, and improve the reaction ability of activated coke to acid flue gas and nitrogen oxides. The reduction performance of the active coke; and then remove the unattached alkaline substances by washing with water; finally, through the high temperature activation of 900-1150 ° C, the active sites of the active coke are reduced and activated, the activity of the active coke groups is enhanced, and the excess water of the active coke is removed. The process of improving the performance of active coke can be carried out after the active coke is regenerated about 4 to 10 times, so that it can achieve higher activity and obtain the best market value under the premise of good structural strength.

The high-temperature flue gas generated by the regeneration of activated coke is sent to the front end of the GGH heat exchanger, and after heat exchange, it enters the ammonia desulfurization and denitrification integrated tower and the dry integrated purification tower for purification and discharge.

The water in the second washing process is relatively clean weak alkaline water, which can be reused in the first washing process to neutralize the acidic substances adsorbed in the active coke and improve the utilization rate of alkali; The waste water is sent to the water treatment section for purification.

Outstanding effect and advantage of the present invention

(1) Resource recycling

Ammonia desulfurization uses the ammonia distillation condensate in the ammonia distillation section of the factory area for desulfurization, and the desulfurization product ammonium sulfate solution is used to prepare soil conditioners. The coke powder and dedusting ash produced during the screening of activated coke are used for coal blending to produce coke, and no waste is generated in the whole system.

(2) Efficient use of heat

The process adopts GGH heat exchanger for heat exchange, and uses the heat of the original flue gas to reheat the desulfurized flue gas. It achieves the denitrification process conditions and the temperature conditions for tail gas dewhitening without external heating sources.

(3) Ammonia escape control for ammonia desulfurization

After the combination of ammonia desulfurization and activated coke denitrification technology, the ammonia escaped from ammonia desulfurization can be used as a reducing agent for activated coke denitrification, thereby consuming the escaped ammonia and achieving the purpose of controlling ammonia escape.

(4) Whitening, dioxin and heavy metal removal

Through system coupling, the whole system performs dust removal, temperature rise, adsorption and other processes on the flue gas to achieve the purpose of flue gas whitening, dioxin removal, and heavy metal removal.

(5) Reduce the amount of denitrification reducing agent

After the combination of ammonia desulfurization and activated coke denitrification technology, the ammonia escaped from ammonia desulfurization can be used as a reducing agent for activated coke denitrification, thereby reducing the use of external ammonia.

(6) The flue gas can be returned to the chimney for discharge, and the system has a single exhaust port

This process does not require a separate hot standby treatment for the chimney. After the system is heated by GGH, the flue gas temperature reaches 120±20°C, and the flue gas can be sent into the chimney for discharge. The whole system has only one outlet.

(7) Extended active coke analysis cycle

Compared with the active coke desulfurization and denitrification integrated process, the active coke analysis cycle of the process of the present invention is longer, which saves a lot of analysis costs.

(8) Active coke can be recycled and reused

Through the process of this system, the active coke not only satisfies the regeneration and use of the system, but also solves the disadvantages of excessive regeneration and waste of active coke, and prepares it into higher-value high-performance active coke products, maximizing economic benefits .

The coke oven flue gas integrated purification and by-product resource utilization system and its process according to the present invention will be further described below in conjunction with the description of the drawings and specific embodiments.

Description of drawings

Figure 1 is a schematic diagram of a coke oven flue gas integrated purification and by-product resource utilization system;

Figure 2 is a process flow diagram of the coke oven flue gas integrated purification and by-product resource utilization system;

Figure 3 is a diagram of the concentration change of flue gas after passing through each purification section of the system; specifically, after the incoming gas passes through ammonia desulfurization (WFGD) + photooxygen demist and dust removal purification section (APDT) + active coke integrated purification process (IFGC) Changes in concentration of SO ₂ , NO ₂ , and dust after purification in each purification stage;

Figure 4 is a diagram of the removal rate of flue gas after passing through each purification section of the system; specifically, after the incoming gas passes through ammonia desulfurization (WFGD) + photooxygen demist and dust removal purification section (APDT) + active coke integrated purification process (IFGC) The removal rate of SO ₂ , NO ₂ , and dust content after purification in each purification stage.

Detailed ways

As shown in Figure 1, a coke oven flue gas integrated purification and by-product resource utilization system includes dust removal equipment 1, temperature adjustment equipment 2, booster fan 3, GGH heat exchanger 4 and desulfurization and denitrification integrated purification Tower 6, the top of the desulfurization and denitrification integrated purification tower 6 is provided with a photooxygen defogging and dust removal purification section 5, and the outlet of the photooxygen demisting and dust removal purification section 5 is connected with the GGH heat exchanger 4, and the GGH heat exchanger 4 is also sequentially installed There are ammonia injection section 7 and dry integrated purification tower 8.

The inlet temperature of the desulfurization and denitrification integrated purification tower 6 is 120-140°C, the flow velocity of the desulfurization section (that is, the lower half of the desulfurization and denitrification integrated purification tower 6 is 3-5m/s, and the flow velocity of the photo-oxygen demisting and dust-removing purification section is 2-5m/s. 4m/s; the pH of the liquid at the bottom of the desulfurization section is 6.5-7.5, and the density of the ammonium sulfate solution and ammonia water solution at the bottom of the desulfurization section is 1.03-1.08mg/cm ^{3 .} When less than or equal to 1.03, stop the slurry pump.

The inlet temperature of the dry integrated purification tower 8 is 120±20° C., and the flue gas velocity in the dry integrated purification tower 6 is 0.25 m/s.

As shown in Figure 2, the coke oven flue gas integrated purification and by-product resource utilization process using the above system is as follows:

After the coke oven flue gas is drawn out from the underground flue, it is dedusted by dust removal equipment, and the boiler, air cooler, and water cooler are individually or combined with temperature adjustment equipment 2 to 200±20°C, and the flue gas is pressurized by the booster fan 3 before being sent into the GGH heat exchanger 4, GGH heat exchanger 4 lowers the flue gas temperature to 120-140°C and enters the desulfurization and denitrification integrated purification tower 6, where the flue gas is in countercurrent contact with ammonia water to remove the pollutants in the flue gas Sulfur dioxide, some nitrogen oxides and particulate matter.

After the flue gas is desulfurized, the temperature is lowered to about 50-70°C, and at the top of the desulfurization and denitrification integrated purification tower 6, it passes through the photo-oxygen demisting and dust-removing purification section 5, in which a large amount of water vapor and dust in the flue gas are captured and removed; Oxygen mist removal and dust removal purification section 5 can remove 40% of nitrogen oxides.

After the flue gas is exchanged by the GGH heat exchanger 4 again, the temperature rises from 50-70°C to 120±20°C. After the ammonia water is sprayed into the flue gas through the atomizer in the ammonia injection section 7, the flue gas enters the dry integration process. The purification tower 8 removes sulfur dioxide, nitrogen oxides, particulate matter, dioxins, and heavy metals in the flue gas; the purified flue gas is passed into the chimney 9 to be discharged.

Among them, the photo-oxygen demist and dust removal purification section 5 is equipped with a high-efficiency fog and dust removal system and a photo-oxygen catalytic oxidation system.

The high-efficiency fog and dust removal system specifically includes (from bottom to top): 2-layer plate-type mist eliminator + 1-layer tube bundle turbulent flow fogger, dust collector);

The specific plan is: the flue gas first passes through the 2-layer plate demister to remove most of the large droplets and dust with a large diameter, and then passes through the tube bundle turbulent flow demister to remove most of the small droplets and dust with a small diameter, and then passes through the WESP (wet electronic precipitator) to remove the tiny dust in the flue gas to reduce the dust content below the emission requirements. If the resistance of the desulfurization tower exceeds a certain limit, turn on the spray flushing system (or turn it on regularly) to flush the mist eliminator and dust removal device.

The photo-oxygen catalytic oxidation system consists of reaction trays, nano-materials, UV light source, H ₂ O ₂ injection system, BAC layer, and flushing spray system. Specifically: spray nanomaterials on the top of WESP (wet electronic precipitator), and set UV light source on the upper part of WESP (wet electronic precipitator), and add _H2O2 injection system in this section, and set reaction _tray above it , and below are coated with nanomaterials), a UV light source is set above the reaction tray, and a BAC (activated carbon) layer is set up.

The specific scheme is: the front and back of the reaction tray are coated with nanomaterials, and the UV light source irradiates the nanomaterials on both sides of the reaction tray to generate free hydroxyl groups (·OH) and active oxygen (O ₂ ^- ) with strong oxidizing ability, and at the same time According to the NOx concentration, H ₂ O ₂ can be sprayed. When the flue gas passes through the photo-oxygen catalytic oxidation system, a photocatalytic oxidation reaction occurs, so that SO _X and NOx are oxidized to SO ₄ ^2- and NO ₃ ^- , after being washed by the spray flushing system The formation of sulfate and nitrate falls to the bottom of the desulfurization tower, and the BAC layer set on the top of the photo-oxidation catalytic oxidation reaction section, through the combined structure and effect of biological activated carbon (BAC) adsorption enrichment, water film capture and biochemical decomposition, on the one hand prevents O ₃ , etc. escape and pollute the environment, on the other hand, it absorbs and decomposes SO _x , NO _x and other polluting components in the flue gas.

The by-products of the system are the concentrated ammonium sulfate solution discharged from the desulfurization and denitrification integrated purification tower, and the saturated activated coke discharged from the dry integrated purification tower; Coal blending in the coking plant to produce coke; saturated activated coke particles need to be sieved after regeneration, and the regenerated activated coke particles reaching the particle size are sent back to the dry process integrated purification tower for recycling; the undersieve is combined with concentrated ammonium sulfate solution to prepare soil conditioner ; The saturated active coke is regenerated and recycled to prepare high-performance activated coke and activated carbon products.

The saturated active coke discharged from the dry integrated purification tower is transported to the regeneration converter, which is heated to 300-400°C and fed with steam (2-3 bar) for regeneration. The sulfur inside the saturated active coke is decomposed at high temperature out, the active coke is regenerated, and the regenerated active coke is sent back to the dry integrated purification tower for continued use. The undersize and dust ash can be used to prepare soil improvers. The regeneration process can be cycled up to 7 times. The decomposed acidic flue gas is sent to the front end of the dust removal equipment, and after heat exchange, it enters the ammonia desulfurization and denitrification integrated tower and the dry integrated purification tower for purification before being discharged.

Among them, the saturated activated coke or activated carbon discharged from the dry-process integrated purification tower after 4 to 10 cycles of use and regeneration of the dry-process integrated purification tower and regeneration converter is washed and soaked for 1 to 2 hours to dissolve the acidic components. , washed with 5% ammonia water and soaked for 0.5 hours, then washed with fresh running water until the pH of the effluent is between 8 and 9, then transported to the activation furnace, and activated at 900 to 1150 ° C in the activation furnace to obtain high performance. Activated coke or activated carbon; the high-temperature tail gas generated during the regeneration and activation of activated coke and activated carbon can be sent to the front end of the dust removal equipment, and after heat exchange, it enters the desulfurization and denitrification integrated purification tower and the dry integrated purification tower to be purified and then discharged. The water in the second washing process is relatively clean weakly alkaline water, which can be reused in the first washing process to neutralize the acidic substances adsorbed in the active coke and improve the utilization rate of alkali; alkaline washing and the first water washing The waste water is sent to the water treatment section for purification.

The concentration change of the flue gas after each purification stage and the removal rate of the flue gas after each purification stage are shown in Figure 3-4.

Among them, the "outlet" in Figure 3 is set in the middle and upper part of the chimney as the outlet monitoring point of the whole system. The "IFGC outlet" is set on the flue at the outlet of the IFGC equipment to monitor the flue gas at the outlet of the IFGC equipment. In the flow chart in Figure 1, the monitoring data of the "outlet" and "IFGC outlet" are the same, but the positions of the monitoring points are different.

From the effect data of this system, it can be clearly seen that SO ₂ and NOx in the flue gas have been discharged up to the standard, and the pollutants such as dioxins and heavy metals in the flue gas have been effectively purified, and ammonia escape and white smoke have been eliminated. Feather and other issues.

After the activated coke flue gas is purified in this system, the saturated activated coke can be regenerated 4 to 10 times at 300-400°C, and the activated coke with reduced performance can be prepared by processes such as water washing, alkali washing, water washing, and 900-1150°C activation. Activated carbon for added value.

When this system produces high-quality active coke for denitrification, the specific surface area (BET) of the initially installed active coke is 200-300m ² /g, the desulfurization value is ≥25mg/g, and the denitrification rate is ≥60%. The specific surface area (BET) of the active coke is 400-500m ² /g, the desulfurization value is ≥40mg/g, and the denitrification rate is ≥80%.

When this system produces high-quality activated carbon, the specific surface area (BET) of the initially loaded activated carbon is 200-300m ² /g, and the iodine adsorption value is ≥200mg/g; after regeneration and upgrading by this system, the specific surface area (BET) of the activated carbon is 800- 1000m ² /g, iodine adsorption value ≥ 800mg/g.

The above-mentioned embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Variations and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (10)

1. A coke oven flue gas integrated purification and byproduct recycling process is characterized in that: the method comprises the steps of (1) dedusting coke oven flue gas, regulating the temperature to 200+/-20 ℃ through a temperature regulating device (2), pressurizing the flue gas to 7500+/-500 Pa through a pressurizing fan (3), sending the coke oven flue gas into a hot side inlet of a GGH heat exchanger (4), reducing the temperature of flue gas at a hot side outlet of the GGH heat exchanger (4) to 120-140 ℃, sending the flue gas into a desulfurization and denitrification integrated purification tower (6), and enabling the flue gas to be in countercurrent contact with ammonia water in the desulfurization and denitrification integrated purification tower (6) to remove sulfur dioxide, partial nitrogen oxides and particulate matters in the flue gas; the temperature of the flue gas after desulfurization is reduced to 50-70 ℃, and free water, sulfur oxides and nitrogen oxides in the flue gas are further removed through a photooxidation defogging dust removal purification section (5) at the top of a desulfurization and denitrification integrated purification tower (6); after the flue gas enters the GGH heat exchanger (4) again for heat exchange, the temperature is increased from 50-70 ℃ to 120+/-20 ℃, ammonia water is sprayed into the flue gas in the ammonia spraying section (7) through an atomizer, and the flue gas enters the dry method integrated purifying tower (8) to remove sulfur dioxide, nitrogen oxides, particulate matters, dioxin and heavy metals in the flue gas; the purified flue gas is led into a chimney (9) for emission;

the system by-product is saturated active coke discharged from a desulfurization and denitrification integrated purification tower (6) and a dry integrated purification tower (8); the saturated active coke is sieved, the complete saturated active coke particles on the sieve are regenerated by a regenerating furnace, and the undersize is used for preparing coke by blending coal in a coking plant; sieving is needed after the saturated active coke particles are regenerated, and the regenerated active coke particles with the particle size are sent back to the dry method integrated purifying tower for recycling; the undersize is combined with concentrated ammonium sulfate solution to prepare a soil conditioner; the saturated active coke is recycled for 4 to 10 times and then is used for preparing active coke and active carbon products with high performance.

2. The coke oven flue gas integrated purification and byproduct recycling process according to claim 1, wherein: a high-efficiency defogging and dedusting system and a photo-oxygen catalytic oxidation system are arranged in the photo-oxygen defogging and dedusting purification section (5);

the efficient demisting and dedusting system specifically comprises a 2-layer plate type demister, a 1-layer tube bundle turbulence demister and a WESP wet type electronic dust collector which are arranged from bottom to top, wherein each layer is provided with a spray flushing system;

during operation, the flue gas firstly passes through a 2-layer plate type demister to remove most of large liquid drops and smoke dust with larger diameter, then passes through a tube bundle turbulence demister to remove most of small liquid drops and smoke dust with smaller diameter, and passes through a WESP wet type electronic dust remover to remove micro liquid drops and smoke dust in the flue gas;

the photo-oxygen catalytic oxidation system comprises a reaction tower plate, a nano material, a UV light source and H ₂ O ₂ The system comprises a spraying system, a BAC layer and a flushing spraying system; the front and back sides of the reaction tower plate are coated with nano materials; wherein, the top end of the WESP wet type electronic dust collector is sprayed with nano materials, the upper part of the WESP wet type electronic dust collector is provided with a UV light source, and meanwhile, the section is additionally provided with H ₂ O ₂ The jet system is provided with a reaction tray above which a UV light source is arranged and a BAC layer is arranged upwards;

when in operation, the UV light source irradiates the nano material on the two sides of the reaction tower plate to generate free hydroxyl (OH) and active oxygen (O) with strong oxidizing ability ₂ ^- ) At the same time, H can be injected according to the concentration of NOx ₂ O ₂ When the flue gas passes through the photo-oxygen catalytic oxidation system, photo-catalytic oxidation reaction occurs to make SO _X And oxidation of NOx to SO ₄ ^2- And NO ₃ ^- The sulfate and nitrate formed after being washed by a spray washing system fall into the bottom of the desulfurization tower, and the BAC layer arranged at the top of the photo-oxygen catalytic oxidation reaction section prevents O by the combined structure-effect of biological activated carbon BAC adsorption enrichment, water film trapping and biochemical decomposition ₃ Dissipation, environmental pollution, adsorption and decomposition of SO in flue gas _X 、NO _x 。

3. The coke oven flue gas integrated purification and byproduct recycling process according to claim 1, wherein: the desulfurization and denitrification integrated purification tower (6) can utilize ammonia evaporation condensate of an ammonia evaporation working section in a factory to carry out desulfurization when being applied in a coking plant; and preparing the soil conditioner by using the desulfurization product-ammonium sulfate solution of the desulfurization and denitrification integrated purification tower (6).

4. The coke oven flue gas integrated purification and byproduct recycling process according to claim 1, wherein: after the coke oven flue gas is led out from the underground flue, if the dust content of the flue gas exceeds 100mg/Nm ³ A dust removal device (1) is additionally arranged for dust removal; the temperature of the outlet flue gas of the temperature regulating device (2) is 200+/-20 ℃, and the temperature can be realized by a single mode or a combined mode of a waste heat boiler, an air cooler and a water cooler.

5. The coke oven flue gas integrated purification and byproduct recycling process according to claim 1, wherein: the photooxidation demisting, dedusting and purifying section (5) can remove 20-40% of nitrogen oxides.

6. The coke oven gas integrated purification and byproduct recycling system adopted by the process of any one of claims 1-5, which is characterized in that: including continuous dust collecting equipment (1), tempering equipment (2), booster fan (3), GGH heat exchanger (4) and integrative purifying column (6) of SOx/NOx control in proper order, the top of integrative purifying column (6) of SOx/NOx control is equipped with light oxygen defogging dust removal purification section (5), the export of light oxygen defogging dust removal purification section (5) is linked together with GGH heat exchanger (4), still be equipped with ammonia spraying section (7) and dry process integration purification column (8) after GGH heat exchanger (4) in proper order.

7. The coke oven flue gas integrated purification and byproduct recycling system according to claim 6, wherein: a high-efficiency defogging and dedusting system and a photo-oxygen catalytic oxidation system are arranged in the photo-oxygen defogging and dedusting purification section (5);

the efficient demisting and dedusting system specifically comprises a 2-layer plate type demister, a 1-layer tube bundle turbulence demister and a WESP wet type electronic dust collector which are arranged from bottom to top, wherein each layer is provided with a spray flushing system;

the photo-oxygen catalytic oxidation system comprises a reaction tower plate, a nano material, a UV light source and H ₂ O ₂ The system comprises a spraying system, a BAC layer and a flushing spraying system; the front and back sides of the reaction tower plate are coated with nano materials; wherein, the top end of the WESP wet type electronic dust collector is sprayed with nano materials, the upper part of the WESP wet type electronic dust collector is provided with a UV light source, and meanwhile, the section is additionally provided with H ₂ O ₂ And the spraying system is provided with a reaction tray above which a UV light source is arranged, and a BAC layer and a spraying layer are arranged upwards.

8. The coke oven flue gas integrated purification and byproduct recycling system according to claim 7, wherein: the inlet temperature of the desulfurization and denitrification integrated purification tower (6) is 120-140 ℃, the flow rate of the desulfurization section is 4-10 m/s, and the flow rate of the photooxidation demisting and dedusting purification section is 2-4 m/s; the pH value of the liquid at the bottom of the desulfurization section is 6.5-7.5; the density of the ammonium sulfate solution and the aqueous ammonia solution at the bottom of the desulfurization section is 1.03-1.08 mg/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The inlet temperature of the dry method integrated purification tower (8) is 120+/-20 ℃, and the flow rate of the flue gas in the dry method integrated purification tower (8) is 0.2-0.3 m/s.

9. The coke oven flue gas integrated purification and byproduct recycling system according to claim 8, wherein: saturated active coke discharged from the dry method integrated purifying tower (8) is transported and conveyed to a regenerating converter, the regenerating converter is heated to 300-400 ℃, steam is introduced, the pressure is 2-3 bar, the regenerating is carried out, sulfur in the saturated active coke is resolved at high temperature, the active coke is regenerated, the regenerated active coke is returned to the dry method integrated purifying tower (8) for continuous use, and the undersize and the dust ash can be used for preparing a soil conditioner, and the regenerating process is circulated for 10 times at most; the analyzed acid flue gas is sent to the front end of the dust removing equipment (1), enters an ammonia desulfurization and denitrification integrated tower (3) and a dry method integrated purification tower (8) after heat exchange, and is discharged after purification.

10. The coke oven flue gas integrated purification and byproduct recycling system according to claim 9, wherein: when the active coke deacidifies and purifies the flue gas in the dry method integrated purifying tower (8), deacidifying the product H ₂ SO ₄ 、HNO ₃ The ash in the active coke is dissolved by HCl, HF and the like, and the ash is combined with water in the flue gas to generate erosion pore-forming effect, so that new pores and channels are formed, the specific surface area is enlarged, and the functional groups of the active coke are enriched. The saturated active coke discharged from the dry integrated purifying tower (8) is washed and soaked for 1-2 hours to dissolve out acid components, then is washed and soaked for 0.5 hour by 5% ammonia water alkali, is washed by fresh running water until the effluent water is between pH8 and 9, is transported to an activating furnace for activation, and is activated in the activating furnace at 900-1150 ℃ to obtain high-performance active coke or active carbon; the high-temperature tail gas generated in the regeneration and activation of the active coke and the active carbon can be sent to the front end of the dust removing equipment (1), and enters an ammonia desulfurization and denitrification integrated (3) tower and a dry method integrated purification tower (8) for purification and then is discharged after heat exchange; the water in the second water washing process is alkalescent water, and can be recycled in the first water washing process to neutralize acidic substances adsorbed in the active coke; the waste water of alkali washing and first water washing is sent to a water treatment section for purification.

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