CN204320061U - A kind of reclaiming device realizing discarded object in flue gas purifying method - Google Patents

Abstract

The utility model discloses a recovery and regeneration device for waste in a flue gas purification method. The recovery and regeneration device includes a waste water regeneration system connected with flue gas purification equipment. A treatment unit for desulfurization and denitrification, the waste water regeneration system is a reuse unit for separating the desulfurization and denitrification waste water of the flue gas purification unit and producing Na ₂ SO ₄ and NaNO ₃ products respectively. The device is easy to operate, not only can remove pollutants in the original flue gas, reduce environmental pollution, but also can obtain Na ₂ SO ₄ , NaNO ₃ products, which greatly reduces the cost of air pollutant treatment, avoids secondary pollution, and has the advantages of Good social benefits and economic value.

Description

A device for recovering and regenerating waste in a flue gas purification method

technical field

The utility model relates to a device for recovering and regenerating waste in a flue gas purification method, in particular to the absorption and regeneration technology of desulfurization and denitrification waste water in the recovered flue gas, and belongs to the field of industrial flue gas reuse.

Background technique

The continuous progress of petroleum and chemical industries has not only promoted economic development, but also caused pollution to the environment. At present, the global pollution problem has become increasingly serious, and has attracted widespread attention and attention from all over the world, especially coal-fired power plants. , coal-fired boilers, and waste incineration flue gas emissions, etc., have seriously polluted the atmosphere. We know that coal-fired flue gas contains a large amount of harmful substances such as soot, carbon dioxide, SO ₂ and NO _X. Among them, fuel combustion emissions Carbon dioxide is the main substance that causes the greenhouse effect; SO ₂ , NO _X and fly ash particles are the main sources of air pollution; The components are also SO ₂ and NO _x . According to reports, about 70% of China's urban suspended particulate levels exceed the standard, and SO ₂ in the atmosphere around 2/3 of the cities exceeds the standard. Therefore, in order to improve the air quality of the current environment, the control and emission reduction of these pollutants is even more urgent.

According to the state of desulfurization reaction substances in the reaction process, flue gas desulfurization can generally be divided into three categories: wet desulfurization, dry desulfurization and semi-dry desulfurization. The purified gas obtained after desulfurization has removed most of SO _X and NO _X can be discharged from the flue if it meets the emission standards; the product of desulfurization reaction is desulfurization and denitrification wastewater, which is classified according to different treatment methods, usually including discarding method and recycling method. Among them, the discarding method is to discard the waste slag of the desulfurization reaction in a certain way without recycling. Its main advantages are simple equipment, easy operation, low investment and operating costs, but the waste slag needs to occupy a site for stacking, which is likely to cause secondary pollution; The recovery method is to further process the product of flue gas desulfurization, so that it can be recycled as a by-product, turning harm into profit. However, the process is more complicated, the operation is more difficult, and the investment and operation costs are higher. Of course, as countries all over the world pay more and more attention to environmental protection in the process of energy production, the recovery and reuse of desulfurization products has become an indispensable industrial measure for the existing flue gas desulfurization industry.

Patent document CN102489136A (a method for recycling flue gas desulfurization wastewater, 2011.12.16) and patent document CN101531384A (process for preparing electronic grade magnesium hydroxide and ammonium sulfate from flue gas desulfurization circulating slurry by magnesium method, 2009.03.05) respectively reveal that limestone/ In the lime-gypsum wet process and magnesium oxide desulfurization process, the recycling process of desulfurization products gypsum slurry and magnesium sulfate slurry has opened up the prospects for the regeneration and utilization of desulfurization by-products in the limestone/lime-gypsum wet process and magnesium oxide process desulfurization process , but in actual industrial operation, because the flue gas purification products are different according to the different pollutant absorbents, for this reason, the utility model came into being.

Utility model content

The purpose of this utility model is to provide a recovery and regeneration device for waste in the flue gas purification method. The recovery and regeneration device is an industrial equipment for preparing Na ₂ SO ₄ and NaNO ₃ by recovering SOx and NOx in the original flue gas. The gas is firstly processed by the flue gas purification equipment to obtain purified gas. The SOx and Nox in the original flue gas are captured into the desulfurization and denitrification wastewater to form a mixed solution containing a certain concentration of sodium sulfate and sodium nitrate, and then pass through the wastewater regeneration system. Produce Na ₂ SO ₄ and NaNO ₃ products. This device is easy to operate. It can not only remove pollutants in the original flue gas and reduce environmental pollution, but also obtain Na ₂ SO ₄ and NaNO ₃ products, which greatly reduces air pollution. It reduces the cost of material treatment, avoids secondary pollution, and has good social and economic value.

The utility model is realized through the following technical scheme: a device for recycling waste in the flue gas purification method, the recycling device is an industrial equipment for preparing Na ₂ SO ₄ and NaNO ₃ by recovering SOx and NOx in the original flue gas , its structure is as follows: the recovery and regeneration device includes a wastewater regeneration system connected with flue gas purification equipment, the flue gas purification equipment is a processing unit for realizing the desulfurization and denitrification of the original flue gas, and the waste water regeneration system is to separate flue gas The gas purification unit desulfurizes and denitrates waste water and makes Na ₂ SO ₄ and NaNO ₃ reuse units respectively. The utility model has simple operation process and low operation difficulty. It can not only remove pollutants in the original flue gas but also obtain Na ₂ SO ₄ , NaNO ₃ products greatly reduce the cost of air pollutant treatment and avoid secondary pollution.

In the utility model, the flue gas purification equipment includes a flue gas rough purification system and an absorption tower which are sequentially connected to the main flue, and the raw flue gas is successively purified by the flue gas and washed by the absorption tower to remove most of the SOx and NOx pollutants are removed by producing a mixed solution containing a certain concentration of sodium sulfate and sodium nitrate, that is, desulfurization and denitrification wastewater. The flue gas rough purification system involved in the utility model overcomes the traditional flue gas purification system. The powder machine system is crushed into absorbent particles, and then sent into the main flue through the dry powder injector to mix and react with the original flue gas. The flue gas purification system described in the utility model is mainly composed of interconnected auxiliary flue Composed of the main flue, the main flue is connected to the main flue and the absorption tower, and an impact mill pulverizing classifier is arranged in the auxiliary flue, and the impact mill pulverizing classifier is used to realize the pulverization of the absorbent And sent to the gas powder conveying device of the main flue together with the auxiliary flue gas. In actual operation, the raw flue gas from the main flue is transported to the absorption tower along the main flue, and a part of the raw flue gas passes through the entrance of the auxiliary flue. The other part of the original flue gas remains in the main flue, called flue gas. In the actual application process, the volume ratio of flue gas to auxiliary flue gas is (9～ 39): 1. The auxiliary flue gas drives the absorbent into the impact mill crushing classifier. The absorbent is pretreated in the impact mill crushing classifier and reacts with the auxiliary flue gas. The obtained gas-powder mixture passes through the outlet of the auxiliary flue It is sent to the main flue, and then mixed with the flue gas in the main flue, and then sent to the absorption tower. The absorbent in the gas powder mixture is active due to the reaction, and is sent to the main flue and flue When the gas is mixed and reacted, its desulfurization and denitrification efficiency is also high, and the actual use effect is good.

The main flue is a flue gas passage for the flue gas to pass through. In order to improve the sufficient mixing and contact of the gas-powder mixture and the flue gas, the utility model is provided with a gas mixer on the main flue; The auxiliary flue is a flue gas bypass channel connected with the main flue, and the outlet of the auxiliary flue is connected to the gas mixer.

In order to better realize the above structure, the utility model is also provided with a flue gas booster fan on the main flue, and the flue gas booster fan is arranged in front of the entrance of the auxiliary flue.

In the actual production process, the layout of the impact mill, pulverizer and classifier can be set in the following two ways:

One is that the impact mill, crushing and classifying machine includes a pulverizer, a classifier and a high-pressure induced draft fan arranged in the auxiliary flue, and the pulverizer, the classifier and the high-pressure induced draft fan are arranged along the conveying direction of the auxiliary flue gas. Set up in sequence, an absorbent inlet is provided on the pulverizer, the auxiliary flue gas is sent into the pulverizer, classifier and high-pressure induced draft fan sequentially along the auxiliary flue, and the absorbent and auxiliary flue gas are sent into the pulverizer, The absorbent is dispersed and turbulent in the space of the pulverizer, and is crushed through the synergistic effect of the pulverizer and the auxiliary flue gas. The crushed absorbent is sent to the classifier for screening under the drive of the auxiliary flue gas, and a part of the absorbent is absorbed The absorbent is mixed with the flue gas to form a gas-powder mixture, which is sent to the gas mixer through a high-pressure induced draft fan, and the other part of the absorbent is returned to the pulverizer for further pulverization.

An absorbent metering control assembly is arranged at the absorbent inlet, and the absorbent metering control assembly includes an absorbent metering and distributing device, an absorbent conveying device, and an absorbent silo connected in sequence, and the absorbent metering and distributing The device is connected with the absorbent inlet, and the absorbent is first sent into the absorbent silo, then sent to the absorbent metering and distributing device through the absorbent conveying device, and then sent to the pulverizer to realize the metered introduction of the absorbent. , the absorbent is usually excessive, and at the same time, it must be measured according to the content of pollutants in the original flue gas. For the original flue gas, the pollutant content is usually in the range of 200-9000mg/ ^Nm3 . The mixing ratio of the gas is 100-920g/Nm ³ , and the obtained gas-powder mixture is sent to the gas mixer after pretreatment by the impact mill, pulverizer and classifier, and the mixing ratio of the absorbent and the flue gas is 6-46g/Nm ³ .

Since the high-pressure induced draft fan is installed behind the classifier, the mill and classifier operate under negative pressure, which can avoid dust leakage from the mill and classifier, but it is necessary to improve the wear resistance of the high-pressure induced draft fan. Therefore, the utility model The flow channel of the high-pressure induced draft fan is made of wear-resistant material, which has the beneficial effects of increasing the wear resistance of the high-pressure induced draft fan and improving the service life of the high-pressure induced draft fan.

The other is that the impact mill pulverizing classifier includes a high-pressure induced draft fan, a pulverizer, and a classifier arranged in the auxiliary flue, and the described high-pressure induced draft fan, pulverizer, and classifier are along the auxiliary flue gas transportation The direction is set in sequence, and the absorbent inlet is set on the pulverizer, and the absorbent is directly sent to the pulverizer, and the absorbent is dispersed and turbulent in the space of the pulverizer, and passes through the pulverizer and auxiliary flue gas The synergistic effect of the absorbent is broken, and the crushed absorbent is sent to the classifier for screening under the drive of the auxiliary flue gas, and a part of the absorbent is mixed with the auxiliary flue gas to form a gas-powder mixture, which is sent to the gas mixing machine under the power provided by the high-pressure induced draft fan. The other part of the absorbent is returned to the pulverizer for further pulverization.

Further, an absorbent metering control assembly is provided at the absorbent inlet, and the absorbent metering control assembly includes an absorbent metering and distributing device, an absorbent conveying device, and an absorbent silo connected in sequence, and the absorbent The agent metering distribution device is connected with the absorbent inlet.

For the pulverizer, an air pipe is connected to the pulverizer, and the air can also be used to drive the spatial dispersion and turbulence of the absorbent in the pulverizer, so that the pulverization of the absorbent can also be realized, and the operation is very flexible.

In the utility model, the absorption tower is a reaction device equipped with a spray layer and a desulfurization liquid circulation system, the flue gas purification equipment is connected with the absorption tower, and the top of the absorption tower is equipped with a At the bottom of the absorption tower, there is a waste water pipe for the discharge of desulfurization and denitrification waste water. The specific operation process is as follows: the raw flue gas is roughly purified by the flue gas purification equipment and then sent to the absorption tower. The spray layer is arranged in the absorption tower. The nozzles distributed above spray out at high pressure and form a large number of desulfurization mist droplets with large specific surface area. Head-on contact, strong turbulent flow occurs, the gas and liquid two phases undergo sufficient mass and heat transfer, and SO ₂ in the flue gas mixture is absorbed in large quantities; on the other hand, after the absorbent particles in the flue gas mixture enter the tower, the same With the air flow upstream, fully contact with the desulfurization liquid from top to bottom, the excess absorbent particles dissolve into the desulfurization liquid, and the washing slurry (desulfurization and denitrification wastewater) continues to circulate in the tower under the action of the desulfurization liquid circulation system Absorb the residual SO ₂ , NO _Y and heavy metal oxides in the flue gas, and the removal efficiency of SO ₂ can be as high as 99%. The purified gas after desulfurization can be discharged directly from the flue after reaching the national emission standard. During the circulation process, due to the continuous absorption of SO ₂ , after reaching a certain concentration, it is sent to the wastewater regeneration system by the wastewater pipeline.

The wastewater regeneration system is mainly composed of successively connected settling tanks, wastewater evaporators, primary solid-liquid separation equipment, sodium nitrate crystallizers and secondary solid-liquid separation equipment. The described settling tanks are connected to wastewater pipelines. clarification equipment; the waste water evaporator is connected to the clear liquid outlet of the settling tank; the _Na2SO4 suspended solids outlet and the first-stage filtrate outlet are provided on the first-stage solid-liquid separation device _; The solid-liquid separation equipment is equipped with NaNO ₃ suspended solid outlet and secondary filtrate outlet. In the utility model, the desulfurization and denitrification wastewater is sent to the sedimentation tank by the wastewater pipeline, and after the dust and impurities in the desulfurization and denitrification wastewater are clarified by the sedimentation tank, The supernatant liquid is sent to the waste water evaporator for evaporation and concentration to obtain concentrated waste water; then the concentrated waste water is sent to the first-level solid-liquid separation equipment to obtain Na ₂ SO ₄ suspended solids and the first-level filtrate, and the first-level filtrate is sequentially sent to Enter sodium nitrate crystallizer and secondary solid-liquid separation equipment to obtain _NaNO3 suspended solids and secondary filtrate.

A pipeline mixer is provided on the wastewater pipeline, and a flocculant inlet is also provided on the pipeline mixer. The function of the pipeline mixer is to quickly mix the flocculant solution and the washing slurry (ie: desulfurization and denitrification wastewater) evenly , the flocculant is pumped to the pipeline mixer through metering delivery. The position of the pipeline mixer should be as close as possible to the absorption tower to facilitate the flocculation of dust. The desulfurization and denitrification wastewater is flocculated and clarified in the settling tank to flocculate the dust and impurities in the desulfurization and denitrification wastewater. After settling down, the supernatant liquid is sent to the waste water evaporator for evaporation and concentration to obtain concentrated waste water; the precipitated sludge (impurities and dust that have been flocculated) is sent to the waste water filter, and the waste residue obtained by filtering is transported outside, and the filtrate is returned to the waste water for evaporation The device circulates and evaporates and concentrates.

The flocculant is composed of polyacrylamide and sodium polyacrylamide, the mass ratio of polyacrylamide and sodium polyacrylamide is 1:3, wherein sodium polyacrylamide is a linear, soluble polymer Compounds, the carboxyl groups on the molecular chain are due to the electrostatic repulsion, which makes the twisted polymer chains stretch, and promotes the exposure of the adsorptive functional groups to the surface. Because these active points are adsorbed on the suspended particles in the solution, the formation of interparticle The bridging of the suspended particles accelerates the settlement of suspended particles; in addition to having the same effect as sodium polyacrylamide, polyacrylamide can also neutralize the charge on the particle surface to promote flocculation.

The two flocculants are compounded at a ratio of 1:3 to form a composite flocculant, which has the best flocculation effect and can effectively remove dust in the washing slurry (desulfurization and denitrification wastewater), and its light transmittance is comparable to that of a pure solution without dust. The light transmittance is basically the same, which fully shows that the dust removal effect of the solution after flocculation is good, and the combination of these two flocculants is very suitable for the pH value of the desulfurization solution 6-8, which meets the conditions for dust flocculation, without any treatment, and can be directly Add flocculation.

The flocculant described in the utility model is an aqueous solution with a mass fraction of 0.05% to 0.1%. It takes a certain time to dissolve the flocculant, so adding a low-concentration solution makes the mixing effect of the flocculant and the desulfurization liquid better, so as to achieve Better flocculation effect.

The dosage of the flocculant is determined by the dust content in the original flue gas. In the utility model, the dosage of the flocculant is 0.05% to 0.20% of the dust mass in the desulfurization and denitrification wastewater, and the dosage of the composite flocculant is small. Can greatly save operating costs.

The pipeline mixer is a nozzle type, perforated plate type, vortex type or helical blade type pipeline mixer, which can control the flow rate well and complete the flocculation reaction in the mixer without additional reaction zone, and the equipment occupies a small area. Save investment.

In the utility model, the settling tank is an inclined tube settling tank or a scraper settling tank.

The wastewater evaporator involved in the utility model is mainly used to increase the concentration of the washing slurry (desulfurization and denitrification wastewater) so as to separate Na ₂ SO ₄ . The wastewater evaporator is a multi-effect evaporator or an MVR evaporator, and the MVR evaporator is The upgraded product of the traditional evaporator can use low-temperature and low-pressure steaming technology and clean energy as electric energy to generate steam and separate the moisture in the medium. It is an efficient and energy-saving evaporation equipment.

A condensed water pipe is connected between the condensed water outlet of the waste water evaporator and the absorption tower, and the condensed water generated by the waste water evaporator is sent to the absorption tower through the condensed water pipe for use as supplementary water.

A condensed water pipe is connected between the condensed water outlet of the waste water evaporator and the absorption tower, and the condensed water generated by the waste water evaporator is sent to the absorption tower through the condensed water pipe for use as supplementary water.

Further, _a sodium nitrate dryer and a sodium nitrate automatic packaging machine are sequentially connected to the _Na2SO4 suspended solid outlet; a sodium nitrate dryer and a sodium nitrate automatic packaging machine are sequentially connected to the _NaNO3 suspended solid outlet. Packing Machine. The operating principle of the utility model is very simple. The Na ₂ SO ₄ suspended solids and NaNO ₃ suspended solids separated from the washing slurry (desulfurization and denitrification wastewater) are dried and sent to the packaging machine to obtain bagged products. In the actual production process, The selection of equipment is also very simple, it can be selected directly according to the characteristics of the material, and it has a wide range of applications, such as:

The first-stage solid-liquid separation equipment is a scraper discharge centrifuge, a piston pusher centrifuge, a horizontal screw centrifuge or a vacuum belt filter.

The secondary solid-liquid separation equipment is a scraper discharge centrifuge, a piston pusher centrifuge, a horizontal screw centrifuge or a vacuum belt filter.

The sodium nitrate crystallizer is a DTB crystallizer, an OSLO crystallizer or an FC crystallizer, and the DTB type crystallizer belongs to a magma internal circulation crystallizer, which has high production strength and can produce larger grains , and the crystallizer is not easy to scar; the OSLO crystallizer is an OSLO cooling crystallizer, the circulating feed liquid is cooled by an external cooler to achieve supersaturation, and then enters the suspension bed through a vertical pipeline to make the crystal grow, and the produced The crystal has the advantages of large volume, uniform particles, large production capacity, continuous operation and low labor intensity; FC crystallizer is also called forced circulation crystallizer, the crystallization chamber has a conical bottom, and the crystal slurry is discharged from the conical bottom. , through the circulation pipe, sent to the heat exchanger by the circulation pump, after being heated, it enters the crystallization chamber again, and so on, so as to realize the continuous crystallization process.

The sodium sulfate dryer is a vibrating fluidized bed dryer, a rotary dryer, an airflow dryer or a boiling dryer.

The sodium nitrate drier is a vibrating fluidized bed drier, rotary drier, air flow drier or boiling drier.

A heat exchanger is arranged between the first-level solid-liquid separation equipment and the sodium nitrate crystallizer, and the medium inlet end of the heat exchanger is connected with the first-level filtrate outlet and the second-level filtrate outlet respectively; The medium outlet end of the heater is connected with a primary filtrate pipeline for delivering the primary filtrate to the sodium nitrate crystallizer and a secondary filtrate pipeline for transmitting the secondary filtrate to the waste water evaporator. In the utility model, the primary filtrate and the secondary filtrate The primary filtrate is heat-exchanged through a heat exchanger, so that the primary filtrate is cooled and sent to a sodium nitrate crystallizer, so that sodium nitrate can be crystallized by cold crystallization; the secondary filtrate is preheated and then sent to a waste water evaporator for continued concentration and separation of Na ₂ SO ₄ .

Compared with the prior art, the utility model has the following advantages and beneficial effects:

(1) This utility model is a recovery and regeneration equipment for preparing Na ₂ SO ₄ and NaNO ₃ by using SOx and NOx in flue gas. While realizing flue gas purification, it recovers SOx and NOx in flue gas and obtains SOx and NOx containing The desulfurization and denitrification wastewater (washing slurry), the desulfurization and denitrification wastewater through precipitation, separation and regeneration, respectively to obtain Na ₂ SO ₄ and NaNO ₃ products, this process is simple to operate, not only can remove the pollutants in the original flue gas, reduce Environmental pollution, Na ₂ SO ₄ , NaNO ₃ products can also be obtained, which greatly reduces the cost of air pollutant treatment, avoids secondary pollution, and has good social benefits and economic value.

(2) The flue gas rough purification involved in this utility model includes: introducing the absorbent into the impact mill, pulverizer and classifier through the auxiliary flue gas. For desulfurization and denitrification treatment, the absorbent in the gas-powder mixture is active due to the reaction. After being sent into the main flue, it is mixed with the flue gas and reacted, which greatly improves the desulfurization and denitrification efficiency of the absorbent, and is beneficial to the subsequent absorption. The desulfurization and denitrification treatment efficiency of the tower has a very high promotion effect.

(3) The design of the utility model is reasonable, and an auxiliary flue is set on the main flue, and the absorbent is introduced into the impact mill, pulverizer and classifier by the auxiliary flue gas for pretreatment. In the utility model, the airflow entering the impact mill, pulverizer and classifier In order to assist the flue gas, the use of other gases to reduce the concentration of pollutants in the flue gas and the temperature of the flue gas is avoided. At the same time, since the airflow introduced is the auxiliary flue gas, the auxiliary flue gas can also be combined with the absorbent while pretreating the absorbent. The absorbent reacts to make the absorbent active, which is conducive to improving the desulfurization and denitrification efficiency of the flue gas. In the auxiliary flue, the rough purification rate of the flue gas can reach 90% to 99%.

(4) The principle of the utility model is simple. The auxiliary flue gas and absorbent are introduced into the impact mill and classifier for crushing with the high-pressure induced draft fan. The synergistic crushing of the grinding, pulverizing and classifying machine and the auxiliary flue gas has high crushing efficiency, and the specific surface area and porosity of the pretreated absorbent are greatly increased. In the actual use process, the absorbent is crushed to a particle size of ≤40μm, Particles with a pore volume ≥ 0.03 m ³ /g and a specific surface area ≥ 14.02 m ² /g.

(5) The auxiliary flue gas used in this utility model comes from the original flue gas. In actual use, due to the high temperature of the original flue gas, the absorbent can react with the auxiliary flue gas more effectively while being crushed. Improve the treatment efficiency of the absorbent. In actual use, the temperature of the auxiliary flue gas entering the impact mill, pulverizer and classifier can reach 90-200°C, and the actual use effect is good.

(6) The impact mill, pulverizer and classifier involved in this utility model is mainly composed of a pulverizer, a classifier and a high-pressure induced draft fan. Different from the traditional pulverizer system, the impact mill pulverizer and classifier adopted in the utility model cancels the The setting of the traditional cyclone and bag collector avoids the agglomeration of the crushed absorbent, fully maintains the activity of the pre-treated absorbent, and is extremely practical.

(7) The utility model is flexible in operation, and the impact mill pulverizing classifier involved includes two working conditions. One is that the pulverizer and classifier adopt positive pressure operation, which can avoid the wear of the absorbent particles on the fan after pulverization, and reduce the The wear-resistant requirements of the equipment are met; the other is that the mill and classifier are operated under negative pressure, which can avoid dust leakage from the mill and classifier, but the degree of wear-resistant treatment of the high-pressure induced draft fan needs to be improved.

(8) During negative pressure operation, in order to reduce the wear of the absorbent particles on the high-pressure induced draft fan, the flow channel of the high-pressure induced draft fan involved in the utility model adopts anti-corrosion treatment, which can increase the wear resistance of the high-pressure induced draft fan and improve the high-pressure induced draft fan. Beneficial effect on fan life.

(9) The utility model is also equipped with a gas mixer on the main flue, which can fully and evenly mix the gas-powder mixture sent into the main flue with the flue gas, which is beneficial to the adsorption of the absorbent on the flue gas. Coarse purification, in the main flue, the initial purification rate of the introduced gas-powder mixture and flue gas can reach 80-99%, and the desulfurization and denitrification efficiency is high.

(10) While improving the desulfurization and denitrification efficiency in the flue gas rough purification process, the utility model also reduces the purification pressure of the subsequent absorption tower. In the actual operation process, the removal efficiency of the absorption tower for _SO2 in the flue gas mixture can be Up to 99%, the desulfurization slurry produced in the desulfurization process is sent to the recovery and regeneration process for treatment, and no waste water is generated.

(11) The flocculant involved in this utility model can effectively remove the flue gas dust in the flue gas wet desulfurization liquid, and its light transmittance is basically the same as that of the pure solution without dust, which fully shows that the solution after flocculation The dust removal effect is good; the compound flocculant of the utility model is very suitable for the pH value and temperature of the desulfurization liquid, meets the conditions of dust flocculation, and can be directly added to the flocculation without any treatment; 0.05% ~ 0.20% of 0.05%, small dosage, can greatly save operating costs.

(12) The utility model adds flocculant aqueous solution to the desulfurization and denitrification wastewater through the pipeline mixer, and the desulfurization and denitrification wastewater is flocculated and clarified in the settling tank without adjusting the pH value or setting up a reaction zone, and the equipment occupies a small area , saving investment to a great extent.

(13) The pipe mixer of the utility model can be set as a spiral static pipe mixer, and the angle between the inlet pipe of desulfurization and denitrification wastewater and the inlet pipe of flocculant is 12-16°, which can well control the desulfurization The flow velocity of the denitration wastewater in the pipeline mixer is 0.8-1.2m/s, and the flow velocity of the flocculant aqueous solution in the pipeline mixer is 0.9-1.0m/s, and the flocculation reaction is completed in the mixer without additional reaction zones. And the mixing performance is good, the efficiency is high, and the operation is stable.

(14) The flocculation temperature of the utility model is 40-45°C, which is in line with the temperature of desulfurization and denitrification wastewater, and the temperature is stable, so there is no need to frequently adjust the amount of flocculant, and the operation is stable.

(15) The operating principle of the utility model is very simple. The Na ₂ SO ₄ suspended solids and NaNO ₃ suspended solids separated from the desulfurization and denitrification wastewater are dried and sent to the packaging machine to obtain bagged products. In the actual production process, the equipment The selection of the material is also very simple, it can be selected directly according to the characteristics of the material, and it has a wide range of applications.

Description of drawings

Fig. 1 is a schematic flow chart of the utility model.

Fig. 2 is a structural layout diagram of the pulverizer and classifier described in the utility model when they are operated under positive pressure.

Fig. 3 is a structural schematic diagram of the absorption tower described in the present invention.

Among them, 1—main flue, 2—auxiliary flue, 3—spray layer, 4—absorption tower, 5—flue, 6—wastewater pipe, 7—circulation pump, 8—condensate pipe, 9—air pipe, 10—the primary filtrate pipeline, 11—the secondary filtrate pipeline.

Detailed ways

The utility model will be further described in detail below in conjunction with the examples, but the implementation of the utility model is not limited thereto.

Example 1:

The utility model proposes a recycling device for waste in the flue gas purification method, which mainly involves the production process of recovering SOx and NOx in the original flue gas to prepare Na ₂ SO ₄ and NaNO ₃ . In this embodiment, the original The flue gas is firstly processed by the flue gas purification equipment to obtain purified gas. SOx and Nox in the original flue gas are captured into the desulfurization and denitrification wastewater to form a mixed solution containing a certain concentration of sodium sulfate and sodium nitrate, namely: desulfurization and denitrification wastewater, Then Na ₂ SO ₄ and NaNO ₃ in the desulfurization and denitrification wastewater are separated by a wastewater regeneration system to produce Na ₂ SO ₄ and NaNO ₃ products. The device is easy to operate, not only can remove pollutants in the original flue gas, reduce environmental pollution, but also can obtain Na ₂ SO ₄ , NaNO ₃ products, which greatly reduces the cost of air pollutant treatment, avoids secondary pollution, and has the advantages of Good social benefits and economic value.

Example 2:

The difference between this embodiment and Example 1 is that the coarse flue gas purification involved in this embodiment is compared with the traditional flue gas purification method, the absorbent is metered and sent to the pulverizer system for crushing, and the pulverized absorbent particles are passed through The dry powder injector is sent into the main flue 1 to mix and react with the raw flue gas. In the traditional method, the purification efficiency of the absorbent to the raw flue gas is usually about 50%, and the desulfurization efficiency is low. In order to improve the absorbent work efficiency, the present embodiment proposes the following design: the original flue gas in the main flue is sent into the absorption tower 4 through the flue gas system, and the improvement of the flue gas system is that the flue gas system is mainly composed of the auxiliary flue 2 and the interconnected auxiliary flue The main flue is composed of 1. At the same time, an impact mill pulverizing classifier is installed in the auxiliary flue 2. The process flow is as follows: the original flue gas from the main flue is sent to the absorption tower 4 along the main flue 1. The original flue gas is split to form auxiliary flue gas and flue gas. The absorbent is sent to the impact mill, pulverizer and classifier in the auxiliary flue 2 along with the auxiliary flue gas for pretreatment (crushing), and the obtained gas-powder mixture enters the main flue 1. After mixing and reacting with the flue gas, it is sent to the absorption tower 4. In actual operation, the absorbent sent to the impact mill pulverizer with the auxiliary flue gas is pulverized and reacts with the auxiliary flue gas to obtain gas. Powder mixture, the absorbent in the gas-powder mixture is active due to the reaction, and when it is sent to the main flue 1 for mixed reaction with flue gas, its desulfurization and denitrification efficiency is also high. The rough purification rate of the gas can reach 90-99%. After the gas-powder mixture is sent to the main flue 1, the rough purification rate of the flue gas in the main flue 1 can reach 80-90%. At the same time, it can also effectively The design is very reasonable to reduce the purification pressure of the subsequent absorption tower 4 as much as possible.

Example 3:

The difference between this embodiment and Embodiment 2 is that in this embodiment, after the original flue gas is split, the volume ratio of the flue gas passing through the main flue 1 and the auxiliary flue gas passing through the auxiliary flue 2 is 9: 1.

In the actual application process of this embodiment, the original flue gas is sent into the main flue 1 through the flue gas booster fan, and a part of the original flue gas enters the auxiliary flue 2 through the entrance of the auxiliary flue 2, which is called auxiliary flue gas. A part of the original flue gas remains in the main flue 1, which is called flue gas. The auxiliary flue gas drives the absorbent and enters the impact mill crushing classifier together. The absorbent is pretreated in the impact mill crushing classifier and combined with the auxiliary flue gas. reaction, the obtained gas-powder mixture is sent to the main flue 1 through the outlet of the auxiliary flue 2, and then mixed and reacted with the flue gas in the main flue 1, and sent to the absorption tower 4 together.

Example 4:

The difference between this embodiment and Embodiment 3 is that in this embodiment, the impact mill pulverizing classifier is mainly composed of a pulverizer, a classifier and a high-pressure induced draft fan, and the absorbent and auxiliary flue gas are sent into the pulverizer along with the high-pressure induced draft fan. The absorbent is pulverized and then sent to the classifier with the auxiliary flue gas for screening. In the actual operation process, the gas-powder mixture can be selected by adjusting the speed of the classifier. Usually, the particle size of the absorbent in the gas-powder mixture It is controlled at ≤40μm, that is, the absorbent with a particle size of ≤40μm is mixed with auxiliary flue gas to obtain a gas-powder mixture, and the absorbent with a particle size>40μm is returned to the mill for further pulverization.

Since the amount of absorbent introduced is related to the pollutant content in the original flue gas, it is necessary to monitor the pollutants in the original flue gas during actual use. After the absorbent is measured and controlled according to the monitoring data, the The absorbent is fed into the pulverizer. This embodiment is suitable for rough purification of raw flue gas with a pollutant content within the range of 200 mg/Nm ³ . The maximum mixing ratio of the introduced absorbent and auxiliary flue gas is 100 g/Nm ³ . After pretreatment by the impact mill, pulverizer and classifier, the rough purification rate of the absorbent to the auxiliary flue gas can reach 99%.

Example 5:

The difference between this example and Example 4 is that in this example, the absorbent used includes a mixture of NaHCO ₃ , KHCO ₃ , Ca(HCO ₃ ) ₂ , and Mg(HCO ₃ ) ₂ , and in this mixture NaHCO ₃ , KHCO ₃ , Ca(HCO ₃ ) ₂ , and Mg(HCO ₃ ) ₂ have a mass ratio of 1:0.05:0.05:0.05, which can be applied to rough purification of raw flue gas desulfurization and denitrification. The chemical reaction process includes:

Desulfurization: 2HCO ₃ ^— + SO ₂ + ½O ₂ ↔ SO ₄ ^{2 —} + H ₂ O + 2CO ₂ ;

2HCO ₃ ^— + SO ₃ → SO ₄ ^{2 —} + 2 CO ₂ + H ₂ O;

Denitrification: 2HCO ₃ ^— + SO ₂ + NO + O ₂ ↔ SO ₄ ^{2 —} + NO ₂ + H ₂ O + 2CO ₂ ;

2HCO ₃ ^— + 2NO ₂ + ½ O ₂ ↔ 2NO ₃ ^— + H ₂ O + 2CO ₂ ;

4SO ₃ + 2NO ₂ ↔ 4SO ₄ ^{2 —} + N ₂ ;

2NO + 2SO ₂ ↔ 2SO ₃ + N ₂ ;

2HCO ₃ ^— + SO ₃ ↔ SO ₄ ^{2 —} + H ₂ O + 2CO ₂ .

Embodiment 6:

The difference between this example and Example 4 is that in this example, the absorbent used includes a mixture composed of Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , and MgCO ₃ . In this mixture, Na ₂ CO ₃ , K ₂ The mass ratio of CO ₃ , CaCO ₃ , and MgCO ₃ is 1:0.05:0.1:0.05, which is suitable for rough purification of desulfurization and denitrification of raw flue gas. The chemical reaction process includes:

Desulfurization: 2CO ₃ ^— + SO ₂ + ½O ₂ ↔ SO ₄ ^{2 —} + H ₂ O + 2CO ₂ ;

2CO ₃ ^— + SO ₃ → SO ₄ ^{2 —} + 2 CO ₂ + H ₂ O;

Denitrification: 2CO ₃ ^— + SO ₂ + NO + O ₂ ↔ SO ₄ ^{2 —} + NO ₂ + H ₂ O + 2CO ₂ ;

2CO ₃ ^— + 2NO ₂ + ½O ₂ ↔ 2NO ₃ ^— + H ₂ O + 2CO ₂ ;

4SO ₃ + 2NO ₂ ↔ 4SO ₄ ^{2 —} + N ₂ ;

2NO + 2SO ₂ ↔ 2SO ₃ + N ₂ ;

2CO ₃ ^— + SO ₃ ↔ SO ₄ ^{2 —} + H ₂ O + 2CO ₂ .

Embodiment 7:

The difference between this embodiment and embodiment 4 is that: this embodiment is provided with a gas mixer on the main flue 1, and the gas powder mixture and the flue gas are fully mixed and reacted in the gas mixer, in order to ensure the desulfurization and denitrification of the flue gas Efficiency, the mixing ratio of absorbent and flue gas in the gas-powder mixture should be 6g/Nm ³ . In the actual application process, the determination of the amount of absorbent introduced by the pulverizer requires not only the detection of the total amount of pollutants in the raw flue gas, but also the detection of the total amount of pollutants in the main flue 1 after the gas mixer. The detection can only be completed when the two data are jointly fed back to the metering control system of the absorbent. Smoke component detector, the detection signal of the original smoke pollutants is sent to the control system, the control system calculates the total amount of pollution to be treated according to the original smoke detection signal, and then sets the absorption dose to be added, and adds the absorbent The quantity signal is transmitted to the absorbent metering distribution device, and the absorbent is sent to the pulverizer. The purified flue gas detector is installed on the purified flue gas pipeline to automatically detect the pollutants, flow, pressure and temperature of the rough purified flue gas, and the detected flue gas signal is combined with the pulse metering signal of the absorbent metering and distribution device Feedback to the control system, the control system corrects the set value of the absorbent according to the feedback signal and constitutes a complete control system.

Embodiment 8:

The difference between this embodiment and Embodiment 7 is that the high-pressure induced draft fan used in this embodiment is arranged at the front end of the pulverizer, as shown in Figure 2, the auxiliary flue gas is sent into the high-pressure induced draft fan along the auxiliary flue 2, and then sent in sequence Into the pulverizer and classifier, in this embodiment, the pulverizer and classifier are operated under positive pressure, which can avoid the wear of the high-pressure induced draft fan by the absorbent particles after pulverization, and reduce the wear resistance requirements of the equipment. In the actual application process, the absorbent is directly sent to the pulverizer, the absorbent is dispersed and turbulent in the space of the pulverizer, and is crushed through the synergy of the pulverizer and the auxiliary flue gas, and the crushed absorbent is Driven by the auxiliary flue gas, it is sent to the classifier for screening, and a part of the absorbent is mixed with the airflow to form a gas-powder mixture, which is sent to the gas mixer under the power provided by the high-pressure induced draft fan, and the other part of the absorbent is returned to the pulverizer for further pulverization . In the present embodiment, the operating pressure of the high-pressure induced draft fan is 10kPa, a part of the operating pressure is to overcome the resistance of the mill and classifier, about 5kPa, and the other part is to overcome the resistance of the gas mixer, about 5kPa, that is: The pressure of the gas-powder mixture sent to the gas mixer is 5 kPa.

Embodiment 9:

The difference between this embodiment and Embodiment 7 is: the classifier adopted in this embodiment is arranged at the front end of the high-pressure induced draft fan, as shown in Figure 1, the auxiliary flue gas is sent into the pulverizer, classifier and machine successively along the auxiliary flue 2 High-pressure induced draft fan. In this embodiment, the mill and classifier are operated under negative pressure, which can avoid dust leakage from the pulverizer and classifier, but the degree of wear resistance of the high-pressure induced draft fan needs to be improved. In the actual application process, the absorbent and the auxiliary flue gas are sent into the pulverizer, and the absorbent is dispersed and turbulent in the space of the pulverizer, and is crushed through the synergy of the pulverizer and the auxiliary flue gas. Driven by the auxiliary flue gas, the absorbent is sent to the classifier for screening, a part of the absorbent is mixed with the airflow to form a gas-powder mixture, and sent to the gas mixer through a high-pressure induced draft fan, and the other part of the absorbent is returned to the pulverizer to continue smash. In the present embodiment, the operating pressure of the high-pressure induced draft fan is 13kPa, a part of the operating pressure is to overcome the resistance of the mill and classifier, about 8kPa, and the other part is to overcome the pressure of the gas mixer, about 5kPa, that is: sent to The pressure of the gas-powder mixture in the gas mixer is 5 kPa.

In this embodiment, in order to avoid the wear and corrosion of the absorbent particles on the high-pressure induced draft fan, the flow path of the high-pressure induced draft fan should be treated with anti-corrosion treatment, which has the effect of increasing the wear resistance of the high-pressure induced draft fan and improving the service life of the high-pressure induced draft fan Beneficial effect.

Example 10:

The difference between this embodiment and Embodiment 1 is that in this embodiment, the absorption tower 4 includes a spray layer 3 and a desulfurization liquid circulation system. As shown in FIG. 3 , the main flue 1 is connected to the middle of the absorption tower 4. The top of the absorption tower 4 is provided with a flue 5 for discharging the purified gas, and the bottom of the absorption tower 4 is provided with a waste water pipeline 6 for discharging the desulfurized slurry. The specific operation process is as follows: the gas-powder mixture is sent into the main flue 1 The flue gas mixture formed after mixing and reacting with the flue gas is sent to the absorption tower 4 through the main flue 1, and the spray layer 3 is arranged in the absorption tower 4, for example, three layers of spray layers 3 are arranged in the absorption tower 4, After the desulfurization liquid circulation system pressurizes the circulating pump 7, the desulfurization liquid is sprayed out at high pressure from the nozzles distributed on the three-layer spray layer 3, and a large number of desulfurization droplets with a large specific surface area are formed. On the one hand, the flue gas mixture enters the In the middle part of the absorption tower 4, the temperature is rapidly lowered and humidified in the tower, and it is in direct contact with the desulfurization mist droplets moving in the reverse direction at a high speed, and a strong turbulent flow occurs, and the gas and liquid two phases conduct sufficient mass transfer and heat transfer. ₂ is absorbed in a large amount; on the other hand, after the absorbent particles in the flue gas mixture enter the tower, they also go upstream with the air flow and fully contact with the top-down desulfurization liquid, and the excess absorbent particles dissolve into the desulfurization liquid In the process, as the desulfurization slurry circulates in the tower under the action of the desulfurization liquid circulation system to continue to absorb the residual SO ₂ , NO _Y and heavy metal oxides in the flue gas, the coverage rate of the spray mist cone generated by the three-layer nozzle on the cross section of the desulfurization tower It can reach more than 200%, and the removal efficiency of SO ₂ can reach as high as 99%. After the desulfurized purified gas reaches the national emission standard, it can be directly discharged from the flue 5. During the circulation process of the desulfurized slurry, due to the continuous absorption of SO ₂ , when the concentration of Na ₂ SO ₄ in the desulfurization slurry reaches 26%, it will be sent to the sewage treatment station by the waste water pipeline 6. In the above process, the desulfurization solution can be sodium bicarbonate solution or a mixture of sodium carbonate, sodium sulfate, and sodium nitrate.

Example 11:

The difference between this embodiment and Embodiment 10 is that in this embodiment, the flocculant is first transported by a metering delivery pump, which is connected to the waste water pipeline 6 through a pipeline, and its position is as close as possible to the absorption tower 4. The dosage is determined according to the dust content in the raw flue gas. Normally, the dosage of the flocculant is 0.05% of the dust mass in the desulfurization and denitrification wastewater. As shown in Figure 1, in order to quickly and evenly mix the flocculant and washing slurry (ie: desulfurization and denitrification wastewater), a pipeline mixer, such as a nozzle-type pipeline mixer, is arranged on the wastewater pipeline 6, and its position is as close as possible to the absorption tower 4.

The desulfurization and denitrification wastewater mixed with flocculant is sent to the sedimentation tank by the pipeline mixer to flocculate and settle the dust and impurities in the desulfurization and denitrification wastewater, and then the wastewater filter is arranged, and the supernatant liquid in the sedimentation tank is sent to the wastewater evaporator Evaporation and concentration are carried out to obtain concentrated wastewater; the sedimentation sludge in the settling tank is sent to the wastewater filter to flocculate the settled impurities and dust, and the waste residue obtained by filtering is transported outside, and the filtrate is returned to the wastewater evaporator to circulate evaporation and concentration.

In this example, the flocculant is an aqueous solution with a mass fraction of 0.05%, composed of polyacrylamide and sodium polyacrylamide, wherein the mass ratio of polyacrylamide and sodium polyacrylamide is 1:3; the waste water evaporator uses Multi-effect evaporator; settling tank adopts inclined tube settling tank.

Example 12:

The difference between this embodiment and Embodiment 11 is that in this embodiment, a condensed water pipe 8 is connected between the condensed water outlet of the waste water evaporator and the absorption tower 4, the waste water evaporator adopts an MVR evaporator, and the settling tank adopts a scraper settling tank. In actual operation, the supernatant liquid clarified by the settling tank is sent to the MVR evaporator for evaporation and concentration. During the evaporation process, the MVR evaporator will generate a large amount of condensed water. In order to realize the full utilization of condensed water, this embodiment is equipped with The condensed water pipe 8 returns the condensed water produced by the MVR evaporator to the absorption tower 4 for use as supplementary water, which has the purpose of saving energy and reducing consumption, and has a good actual use effect.

Example 13:

The difference between this embodiment and Embodiment 11 is that this embodiment is also provided with a heat exchanger, such as: a plate heat exchanger, and the primary filtrate and the secondary filtrate are heat exchanged through the heat exchanger, so as to cool the primary filtrate. The purpose of the secondary filtrate preheating, its working process is as follows: the primary filtrate and the secondary filtrate are sent into the heat exchanger respectively, and the primary filtrate is sent to the sodium nitrate crystallizer by the primary filtrate pipeline 10 after being cooled by the heat exchanger; After the secondary filtrate is heated up by the heat exchanger, it is sent to the waste water evaporator through the secondary filtrate pipeline 11, evaporated and concentrated again, and then sent to the primary solid-liquid separation equipment to complete the subsequent separation of Na ₂ SO ₄ and NaNO ₃ .

Example 14:

The difference between this example and Example 1 is that in this example, both the first-level solid-liquid separation equipment and the second-level solid-liquid separation equipment use a scraper discharge centrifuge, and the _Na2SO4 obtained from the first-level solid-liquid separation equipment ₄ Suspended solids are dried by a sodium sulfate dryer, and then sent to a sodium sulfate _automatic packaging machine to obtain _Na2SO4 products. _NaNO3 suspended solids obtained from secondary solid-liquid separation equipment are dried by a sodium nitrate dryer, and then sent to nitric acid Sodium automatic packaging machine to obtain _NaNO3 products, among which, sodium sulfate dryer and sodium nitrate dryer are both used as vibrating fluidized bed dryers, and sodium nitrate crystallizers are DTB crystallizers.

Example 15:

The difference between this example and Example 1 is that in this example, both the first-level solid-liquid separation equipment and the second-level solid-liquid separation equipment use piston pusher centrifuges, and the _Na2SO4 obtained from the first-level solid-liquid separation equipment ₄ Suspended solids are dried by a sodium sulfate dryer, and then sent to a sodium sulfate _automatic packaging machine to obtain _Na2SO4 products. _NaNO3 suspended solids obtained from secondary solid-liquid separation equipment are dried by a sodium nitrate dryer, and then sent to nitric acid Sodium automatic packaging machine to obtain _NaNO3 products, among which, sodium sulfate dryer and sodium nitrate dryer are both used as airflow dryers, and sodium nitrate crystallizers are OSLO crystallizers.

Example 16:

This embodiment is suitable for industrial environments where the pollutant content of the original flue gas is 9000 mg/Nm ³ , the original flue gas includes flue gas and auxiliary flue gas with a volume ratio of 39:1, wherein the auxiliary flue gas is along the auxiliary flue 2 The flue gas is sent to the impact mill, pulverizer and classifier, and the flue gas is sent to the gas mixer along the main flue 1.

A pulverizer, a classifier and a high-pressure induced draft fan are arranged in sequence in the auxiliary flue 2, and the auxiliary flue gas is sent to the pulverizer of the auxiliary flue 2 along the entrance of the auxiliary flue 2; the absorbent is first sent into the absorbent silo, Then it is sent to the absorbent metering and distribution device through the absorbent conveying device, and then sent to the pulverizer after metering. The absorbent is dispersed and turbulent in the space in the pulverizer, and is absorbed by the synergistic effect of the pulverizer and auxiliary flue gas. Crushed, the crushed absorbent is driven by the auxiliary flue gas to the classifier for screening, adjust the speed of the classifier to 1000r/min, control the particle size of the crushed absorbent to be ≤20μm, and absorb the particle size of the absorbent >20μm The absorbent returns to the pulverizer to continue crushing, and the absorbent with a particle size of ≤20 μm is mixed with the auxiliary flue gas to obtain a gas-powder mixture; the purpose of the high-pressure induced draft fan is to provide power for the auxiliary flue gas, so that the auxiliary flue gas can drive the absorbent From the pulverizer to the classifier, the obtained gas-powder mixture has a certain pressure and can be stably sent to the gas mixer to react with the flue gas. In this example, NaHCO ₃ is selected as the absorbent, the maximum mixing ratio of its introduction amount and auxiliary flue gas is 920g/Nm ³ , the pressure of the high-pressure induced draft fan is set at 13kPa, and part of the operating pressure is to overcome the pulverizer and classification The resistance of the machine is about 8kPa, and the other part is to overcome the pressure of the gas mixer, which is about 5kPa, that is, the pressure of the gas-powder mixture sent to the gas mixer is 5kPa.

In this embodiment, in order to avoid the wear and corrosion of the absorbent particles on the high-pressure induced draft fan, the flow path of the high-pressure induced draft fan should be treated with anti-corrosion treatment, which has the effect of increasing the wear resistance of the high-pressure induced draft fan and improving the service life of the high-pressure induced draft fan Beneficial effect.

After the absorbent is pretreated by the impact mill, pulverizer and classifier, the rough purification rate of the auxiliary flue gas in the auxiliary flue 2 can reach 95%, and the obtained gas-powder mixture is sent to the gas at a pressure of 5kPa through the outlet of the auxiliary flue 2. The mixer is used to mix with the flue gas in the main flue 1. The maximum mixing ratio of the absorbent in the gas-powder mixture to the flue gas is 46g/Nm ³ . After full mixing and reaction, the flue gas purification rate can be It reaches 85%, without the need for gas-powder separation, and it is directly sent to the subsequent process of flue gas purification—absorption tower 4 through the main flue 1.

In this embodiment, the absorption tower 4 includes a spray layer 3 and a desulfurization liquid circulation system. As shown in FIG. At the bottom of the absorption tower 4, there is a waste water pipeline 6 for discharging the desulfurization slurry. The specific operation process is as follows: the gas-powder mixture is sent into the main flue 1 and the flue gas formed after the flue gas is mixed and reacted The mixture is then sent to the absorption tower 4 through the main flue 1, and the spray layer 3 is arranged in the absorption tower 4, for example, three layers of spray layers 3 are arranged in the absorption tower 4, after the desulfurization liquid circulation system pressurizes the circulation pump 7 , the desulfurization liquid is sprayed at high pressure from the nozzles distributed on the three-layer spray layer 3, and a large number of desulfurization mist droplets with a large specific surface area are formed. On the one hand, the flue gas mixture enters the middle part of the absorption tower 4 and rapidly cools down in the tower Humidification, and head-on contact with the desulfurization droplets moving in the reverse direction at high speed, strong turbulent flow occurs, the gas and liquid two phases conduct sufficient mass and heat transfer, and SO ₂ in the flue gas mixture is absorbed in large quantities; on the other hand, the flue gas After the absorbent particles in the mixture enter the tower, they also go up with the air flow countercurrently and fully contact with the desulfurization liquid from top to bottom. Under the action, the circulation in the tower continues to absorb the residual SO ₂ , NO _Y and heavy metal oxides in the flue gas. The spray mist cone generated by the three-layer nozzle can cover more than 200% of the desulfurization tower section, and the removal of SO ₂ The efficiency can be as high as 99%. The desulfurized purified gas can be discharged directly from the flue 5 after reaching the national emission standard. During the circulation of the desulfurized slurry, due to the continuous absorption of SO ₂ , when the concentration of Na ₂ SO ₄ in the desulfurized slurry After reaching 24%, it is sent to the sewage treatment station by the waste water pipeline 6. In the above process, sodium bicarbonate solution can be used as the desulfurization solution.

The washing slurry is discharged from the waste water pipeline 6 at the bottom of the absorption tower 4, and a pipeline connected to a metering delivery pump is arranged near the absorption tower 4. The metering delivery pump is used to realize the metered addition of the flocculant. In this embodiment, the flocculant is The aqueous solution with a mass fraction of 0.1% is composed of polyacrylamide and sodium polyacrylamide, wherein the mass ratio of polyacrylamide and sodium polyacrylamide is 1:3. In the actual operation process, the amount of flocculant added should be determined according to the dust content in the original flue gas. Usually, the amount of flocculant used is 0.20% of the dust mass in the washing slurry. As shown in Figure 1, in order to quickly mix the flocculant with the washing slurry (i.e. desulfurization and denitrification wastewater) uniformly, a spiral blade pipeline mixer is arranged on the wastewater pipeline 6, and the spiral blade pipeline mixer mixes the flocculant The washing slurry is sent to the inclined tube sedimentation tank to flocculate and settle the dust and impurities in the washing slurry, and then the wastewater filter is arranged, and the supernatant in the inclined tube sedimentation tank is sent to the multi-effect evaporator for evaporation and concentration to obtain concentrated wastewater ; The sedimentation sludge in the settling tank is sent to the waste water filter for flocculation of the settled impurities and dust, and the waste residue obtained by filtration is transported outside, and the filtrate is returned to the multi-effect evaporator to circulate and evaporate and concentrate.

The concentrated waste water obtained by the multi-effect evaporator is sent to the primary solid-liquid separation equipment to realize the separation of Na ₂ SO ₄ , and Na ₂ SO ₄ suspended solids and primary filtrate are obtained respectively, and the primary filtrate is sent to sodium nitrate crystallization in turn device and secondary solid-liquid _separation equipment to realize the separation of NaNO ₃ and obtain NaNO ₃ suspended solids and secondary filtrate respectively _. Automatic packaging machine, Na ₂ SO ₄ product can be obtained; NaNO ₃ suspended solid is dried by sodium nitrate dryer, and then sent to sodium nitrate automatic packaging machine, NaNO ₃ product can be obtained. In the actual production process, the first-level solid-liquid separation equipment and the second-level solid-liquid separation equipment adopt horizontal screw centrifuges, the sodium nitrate crystallizer adopts FC crystallizer, and the sodium sulfate dryer and sodium nitrate dryer adopt rotary dryer .

Example 17:

The difference between this embodiment and Embodiment 16 is that: this embodiment is provided with a tubular heat exchanger between the first-level solid-liquid separation equipment and the sodium nitrate crystallizer, and the first-level filtrate and the second-level filtrate are separated by the tubular heat exchanger. Heat exchange to achieve the purpose of cooling the primary filtrate and preheating the secondary filtrate. The working process is as follows: the primary filtrate and the secondary filtrate are sent to the tubular heat exchanger respectively, and the primary filtrate is sent to the into the sodium nitrate crystallizer; the secondary filtrate is sent to the waste water evaporator after being heated by the heat exchanger, evaporated and concentrated again, and then sent to the primary solid-liquid separation equipment to complete the subsequent separation of _Na2SO4 and _NaNO3 .

Example 18:

The difference between this embodiment and Embodiment 17 is that this embodiment is also connected with an air duct 9 on the pulverizer. With the aid of the external air of the mill, it disperses and turbulences in the space inside the mill, and is crushed through the synergistic effect of the mill and the auxiliary flue gas.

Example 19:

It is suitable for industrial environments where the pollutant content of the original flue gas is 6000mg/Nm3. The original flue gas includes flue gas and auxiliary flue gas with a volume ratio of 14:1. The auxiliary flue gas is sent to the impact mill along the auxiliary flue 2 for crushing Classifier, the flue gas is sent to the gas mixer along the main flue 1.

In the auxiliary flue 2, a high-pressure induced draft fan, a pulverizer and a classifier are sequentially arranged, and the auxiliary flue gas is sent to the high-pressure induced draft fan and the pulverizer in the auxiliary flue 2 along the entrance of the auxiliary flue 2; into the absorbent silo, and then sent to the absorbent metering and distribution device through the absorbent conveying device, and then sent to the pulverizer after metering. The absorbent is dispersed and turbulent in the space of the pulverizer, and passed through the pulverizer and auxiliary The synergistic effect of the flue gas is crushed, and the crushed absorbent is sent to the classifier for screening under the drive of the auxiliary flue gas. The absorbent with a particle size > 30 μm returns to the pulverizer to continue crushing, and the absorbent with a particle size of ≤ 30 μm is mixed with the auxiliary flue gas to obtain a gas-powder mixture; the purpose of the high-pressure induced draft fan is to provide power for the auxiliary flue gas, so that the auxiliary The flue gas can drive the absorbent from the pulverizer to the classifier, and the obtained gas-powder mixture has a certain pressure, which can be stably sent to the gas mixer to react with the flue gas. In this example, Na ₂ CO ₃ is selected as the absorbent, the maximum mixing ratio of its introduction amount and auxiliary flue gas is 150g/Nm ³ , the pressure of the high-pressure induced draft fan is set at 12kPa, and part of the operating pressure is to overcome the And the resistance of the classifier is about 7kPa, and the other part is to overcome the pressure of the gas mixer, about 5kPa, that is: the pressure of the gas-powder mixture sent to the gas mixer is 5 kPa.

After the absorbent is pretreated by the impact mill, pulverizer and classifier, the rough purification rate of the auxiliary flue gas in the auxiliary flue 2 can reach 95%, and the obtained gas-powder mixture is sent to the gas at a pressure of 5kPa through the outlet of the auxiliary flue 2. The mixer is used to mix the flue gas in the main flue 1. The maximum mixing ratio of the absorbent in the gas-powder mixture to the flue gas is 10g/Nm ³ . When it reaches 90%, there is no need for gas-powder separation, and it is directly sent to the subsequent process of flue gas purification-absorption tower 4 through the main flue 1.

In this embodiment, the absorption tower 4 includes a spray layer 3 and a desulfurization liquid circulation system. As shown in FIG. The flue 5 through which the gas is discharged is provided at the bottom of the absorption tower 4 with a waste water pipeline 6 for discharging the desulfurization slurry. The flue gas mixture is then sent to the absorption tower 4 through the main flue 1, and the spray layer 3 is arranged in the absorption tower 4. For example, there are three layers of spray layers 3 arranged in the absorption tower 4, and the desulfurization liquid circulation system adds to the circulation pump 7 After desulfurization, the desulfurization liquid is sprayed at high pressure from the nozzles distributed on the three-layer spray layer 3, and a large number of desulfurization mist droplets with a large specific surface area are formed. On the one hand, the flue gas mixture enters the middle part of the absorption tower 4, Rapid cooling and humidification, and head-on contact with desulfurization mist droplets moving in the opposite direction at high speed, a strong turbulent flow occurs, the gas and liquid two phases conduct sufficient mass transfer and heat transfer, and a large amount of SO ₂ in the flue gas mixture is absorbed; on the other hand, After the absorbent particles in the flue gas mixture enter the tower, they also go up with the air flow countercurrently and fully contact the desulfurization liquid from top to bottom. The excess absorbent particles dissolve into the desulfurization liquid and circulate in the desulfurization liquid with the desulfurization slurry Under the function of the system, the circulation in the tower continues to absorb the residual SO ₂ , NO _Y and heavy metal oxides in the flue gas. The spray mist cone generated by the three-layer nozzle can cover more than 200% of the desulfurization tower section, and the SO ₂ The removal efficiency can reach as high as 99%. The purified gas after desulfurization can be directly discharged from the flue 5 after reaching the national emission standard. During the circulation process of the desulfurization slurry, due to the continuous absorption of SO ₂ , when the Na ₂ SO ₄ in the desulfurization slurry After the concentration of the concentration reaches 26%, it is sent to the sewage treatment station by the waste water pipeline 6. In the above process, sodium bicarbonate solution can be used as the desulfurization solution.

The washing slurry is discharged from the waste water pipeline 6 at the bottom of the absorption tower 4, and a pipeline connected to a metering delivery pump is arranged near the absorption tower 4. The metering delivery pump is used to realize the metered addition of the flocculant. In this embodiment, the flocculant is The aqueous solution with a mass fraction of 0.075% is composed of polyacrylamide and sodium polyacrylamide, wherein the mass ratio of polyacrylamide and sodium polyacrylamide is 1:3. In the actual operation process, the amount of flocculant added should be determined according to the dust content in the original flue gas. Usually, the amount of flocculant used is 0.12% of the dust mass in the washing slurry. As shown in Figure 1, in order to quickly mix the flocculant with the washing slurry (i.e. desulfurization and denitrification wastewater), a porous plate pipeline mixer is arranged on the wastewater pipeline 6, which is located close to the absorption tower 4, and the porous plate pipeline mixer will The washing slurry mixed with flocculant is sent to the scraper sedimentation tank to flocculate and settle the dust and impurities in the washing slurry, and then the waste water filter is arranged, and the supernatant in the scraper sedimentation tank is sent to the MVR evaporator for evaporation and concentration , to obtain concentrated wastewater; the sedimentation sludge in the scraper sedimentation tank is sent to the wastewater filter to filter the settled impurities and dust, and the waste residue obtained by filtering is transported outside, and the filtrate is returned to the multi-effect evaporator to circulate and evaporate and concentrate.

The concentrated wastewater obtained from the MVR evaporator is sent to the first-stage solid-liquid separation equipment to realize the separation of Na ₂ SO ₄ , to obtain Na ₂ SO ₄ suspended solids and the first-stage filtrate respectively, and the first-stage filtrate is sent to the sodium nitrate crystallizer in turn and secondary solid-liquid _separation equipment to realize the separation of NaNO ₃ and obtain NaNO ₃ suspended solids and secondary filtrate respectively _. Packaging machine, Na ₂ SO ₄ product can be obtained; NaNO ₃ suspended solid is dried by sodium nitrate dryer, and then sent to sodium nitrate automatic packaging machine, NaNO ₃ product can be obtained. In the actual production process, the first-level solid-liquid separation equipment and the second-level solid-liquid separation equipment adopt vacuum belt filters, the sodium nitrate crystallizer adopts DTB crystallizer, and the sodium sulfate dryer and sodium nitrate dryer adopt boiling dryer .

Example 20:

The difference between this embodiment and Embodiment 19 is that in this embodiment, a spiral plate heat exchanger is arranged between the primary solid-liquid separation equipment and the sodium nitrate crystallizer, and the primary filtrate and the secondary filtrate are separated by the spiral plate heat exchanger. Heat exchange to achieve the purpose of cooling the primary filtrate and preheating the secondary filtrate. The working process is as follows: the primary filtrate and the secondary filtrate are sent to the tubular heat exchanger respectively, and the primary filtrate is sent to the into the sodium nitrate crystallizer; the secondary filtrate is sent to the waste water evaporator after being heated by the heat exchanger, evaporated and concentrated again, and then sent to the primary solid-liquid separation equipment to complete the subsequent separation of _Na2SO4 and _NaNO3 .

Example 21:

The difference between this embodiment and Embodiment 19 is that this embodiment is also connected with an air duct 9 on the pulverizer. With the aid of the external air of the mill, it disperses and turbulences in the space inside the mill, and is crushed through the synergistic effect of the mill and the auxiliary flue gas.

Example 22:

The difference between this example and Example 16 is that this example is suitable for rough purification of raw flue gas with a pollutant content in the range of 4000 mg/Nm ³ , and the raw flue gas includes flue gas with a volume ratio of 12:1 and Auxiliary flue gas, wherein the auxiliary flue gas is sent to the impact mill crushing classifier along the auxiliary flue 2, and the flue gas is sent to the gas mixer along the main flue 1.

A pulverizer, a classifier and a high-pressure induced draft fan are arranged in sequence in the auxiliary flue 2, and the auxiliary flue gas is sent to the pulverizer of the auxiliary flue 2 along the entrance of the auxiliary flue 2; the absorbent is first sent into the absorbent silo, Then it is sent to the absorbent metering and distribution device through the absorbent conveying device, and then sent to the pulverizer after metering. The absorbent is dispersed and turbulent in the space in the pulverizer, and is absorbed by the synergistic effect of the pulverizer and auxiliary flue gas. Broken, the crushed absorbent is driven by the auxiliary flue gas to the classifier for screening, adjust the speed of the classifier to 800r/min, control the particle size of the crushed absorbent to be ≤30μm, and absorb the particle size of the absorbent >30μm The absorbent returns to the pulverizer to continue crushing, and the absorbent with a particle size of ≤30 μm is mixed with the auxiliary flue gas to obtain a gas-powder mixture; the purpose of the high-pressure induced draft fan is to provide power for the auxiliary flue gas, so that the auxiliary flue gas can drive the absorbent From the pulverizer to the classifier, the obtained gas-powder mixture has a certain pressure and can be stably sent to the gas mixer to react with the flue gas. In this example, the mass ratio of the absorbent is NaHCO ₃ : Mg(HCO ₃ ) ₂ = 1:0.1, the maximum mixing ratio of its introduction amount and auxiliary smoke is 143g/Nm ³ The pressure is set at 12kPa, part of the operating pressure is to overcome the resistance of the mill and classifier, about 7kPa, and the other part is to overcome the pressure of the gas mixer, about 5kPa, that is: the gas-powder mixture sent to the gas mixer The pressure is 5 kPa.

After the absorbent is pretreated by the impact mill, pulverizer and classifier, the rough purification rate of the auxiliary flue gas in the auxiliary flue 2 can reach 92%, and the obtained gas-powder mixture is sent to the The gas mixer is used to mix the flue gas in the main flue 1. The maximum mixing ratio of the absorbent in the gas-powder mixture to the flue gas is 11g/Nm ³ . It can reach 80%, without gas-powder separation, directly sent to the absorption tower 4 through the main flue 1.

In this embodiment, in order to avoid the wear and corrosion of the pollutants in the flue gas on the high-pressure induced draft fan, the flow of the high-pressure induced draft fan should be treated with anti-corrosion treatment, which can increase the wear resistance of the high-pressure induced draft fan and improve the use of the high-pressure induced draft fan. Beneficial effects on longevity.

Example 23:

This embodiment is suitable for rough purification of raw flue gas with a pollutant content in the range of 8000 mg/Nm ³ . The raw flue gas includes flue gas and auxiliary flue gas with a volume ratio of 18:1, wherein the auxiliary flue gas is along the auxiliary flue gas. The flue 2 is sent to the impact mill, pulverizer and classifier, and the flue gas is sent to the gas mixer along the main flue 1.

In the auxiliary flue 2, a high-pressure induced draft fan, a pulverizer and a classifier are sequentially arranged, and the auxiliary flue gas is sent to the high-pressure induced draft fan and the pulverizer in the auxiliary flue 2 along the entrance of the auxiliary flue 2; into the absorbent silo, and then sent to the absorbent metering and distribution device through the absorbent conveying device, and then sent to the pulverizer after metering. The absorbent is dispersed and turbulent in the space of the pulverizer, and passed through the pulverizer and auxiliary The synergistic effect of the flue gas is crushed, and the crushed absorbent is sent to the classifier for screening under the drive of the auxiliary flue gas. The absorbent with a particle size > 20 μm returns to the pulverizer for further crushing, and the absorbent with a particle size of ≤ 20 μm is mixed with the auxiliary flue gas to obtain a gas-powder mixture; the purpose of the high-pressure induced draft fan is to provide power for the auxiliary flue gas, so that the auxiliary The flue gas can drive the absorbent from the pulverizer to the classifier, and the obtained gas-powder mixture has a certain pressure, which can be stably sent to the gas mixer to react with the flue gas. In this example, the absorbent is selected as a mixture with a mass ratio of Na ₂ CO ₃ : K ₂ CO ₃ =1:0.05, and the maximum mixing ratio of its introduction amount and auxiliary flue gas is 247g/Nm ³ , and the high-pressure induced draft fan The pressure is set at 13kPa, part of the operating pressure is to overcome the resistance of the mill and classifier, about 8kPa, and the other part is to overcome the pressure of the gas mixer, about 5kPa, that is: the gas-powder mixture sent to the gas mixer The pressure is 5 kPa.

After the absorbent is pretreated by the impact mill, pulverizer and classifier, the rough purification rate of the auxiliary flue gas in the auxiliary flue 2 can reach 94%, and the obtained gas-powder mixture is sent to the The gas mixer is used to mix the flue gas in the main flue 1. The maximum mixing ratio of the absorbent in the gas-powder mixture to the flue gas is 13g/Nm ³ . After fully mixing and reacting, the purification rate of the flue gas It can reach 89%, without gas-powder separation, and it is directly sent to the absorption tower 4 through the main flue 1.

The above is only a preferred embodiment of the utility model, and does not limit the utility model in any form. Any simple modification or equivalent change made to the above embodiments according to the technical essence of the utility model falls within the scope of the present utility model. Within the protection scope of the present utility model.

Claims (13)

1. one kind realizes the reclaiming device of discarded object in flue gas purifying method, it is characterized in that: described reclaiming device comprises the waste water reclamation system being connected with flue gas purifying equipment, described flue gas purifying equipment is the processing unit realizing former flue gas desulfurization and denitrification, and described waste water reclamation system is separating flue clean unit desulphurization denitration waste water and obtains Na respectively ₂sO ₄and NaNO ₃the recycling unit of product.

2. a kind of reclaiming device realizing discarded object in flue gas purifying method according to claim 1, it is characterized in that: described flue gas purifying equipment comprises the thick cleaning system of the flue gas be connected with main chimney flue successively and absorption tower (4), described flue gas purification system is primarily of the auxiliary flue (2) be interconnected and flue collector (1) composition, described flue collector (1) is communicated in main chimney flue and absorption tower (4), impact grinding pulverizing grading machine is provided with in described auxiliary flue (2), described impact grinding pulverizing grading machine is pulverized for realizing absorbent and delivers to the gas powder conveying device of flue collector (1) in the lump with auxiliary flue gas.

3. a kind of reclaiming device realizing discarded object in flue gas purifying method according to claim 2, is characterized in that: described flue collector (1) is the exhaust gases passes passed through for flue gas, and described flue collector (1) is provided with gas mixer; Described auxiliary flue (2) is the flue gas bypass passageways be connected with flue collector (1), and auxiliary flue (2) port of export is connected on gas mixer.

4. a kind of reclaiming device realizing discarded object in flue gas purifying method according to claim 3, it is characterized in that: described impact grinding pulverizing grading machine comprises flour mill, grader and the high-pressure suction fan be located in auxiliary flue, described flour mill, grader and high-pressure suction fan set gradually along the throughput direction of auxiliary flue gas, and described flour mill is provided with absorbent entrance.

5. a kind of reclaiming device realizing discarded object in flue gas purifying method according to claim 3, it is characterized in that: described impact grinding pulverizing grading machine comprises high-pressure suction fan, flour mill and the grader be located in auxiliary flue (2), described high-pressure suction fan, flour mill and grader set gradually along the throughput direction of auxiliary flue gas, and described flour mill is provided with absorbent entrance.

6. a kind of reclaiming device realizing discarded object in flue gas purifying method according to any one of claim 4 or 5, it is characterized in that: be provided with absorbent measure control assembly at described absorbent entrance, described absorbent measure control assembly comprises the absorbent metered dispensing unit, absorbent conveying device and the absorbent feed bin that are connected successively, and described absorbent metered dispensing unit is connected with absorbent entrance.

7. a kind of reclaiming device realizing discarded object in flue gas purifying method according to claim 6, is characterized in that: on described flour mill, be connected with air duct (9).

8. a kind of reclaiming device realizing discarded object in flue gas purifying method according to claim 2, it is characterized in that: described absorption tower (4) is for being provided with the consersion unit of spraying layer (3) and the doctor solution circulatory system, the thick cleaning system of described flue gas is connected with absorption tower (4), be provided with the flue (5) of discharging for purified gas at the top of absorption tower (4), be then provided with the waste pipe (6) of discharging for desulphurization denitration waste water in the bottom of absorption tower (4).

9. a kind of reclaiming device realizing discarded object in flue gas purifying method according to claim 8, it is characterized in that: described waste water reclamation system is primarily of settling tank, waste water evaporimeter, one-level solid-liquid separating equipment, sodium nitrate crystallizer and the secondary solid-liquid separating equipment composition be connected successively, and described settling tank is the clarifying equipment be connected with waste pipe; Described waste water evaporimeter is connected to the purified liquor outlet of settling tank; Described one-level solid-liquid separating equipment is provided with Na ₂sO ₄suspended solid outlet and one-level filtrate (liquid; Described secondary solid-liquid separating equipment is provided with NaNO ₃suspended solid outlet and secondary filtrate (liquid.

10. a kind of reclaiming device realizing discarded object in flue gas purifying method according to claim 9, is characterized in that: on described waste pipe, be provided with pipe-line mixer, this pipe-line mixer is also provided with flocculant entrance.

11. want a kind of reclaiming device realizing discarded object in flue gas purifying method described in 9 according to right, it is characterized in that: between the condensation-water drain and absorption tower of described waste water evaporimeter, be connected with condensate pipe (8).

12. a kind of reclaiming devices realizing discarded object in flue gas purifying method according to claim 9, is characterized in that: at described Na ₂sO ₄suspended solid outlet is connected with dried over sodium sulfate machine and sodium sulphate automatic packaging machine in turn; At described NaNO ₃suspended solid outlet is connected with sodium nitrate drying machine and sodium nitrate automatic packaging machine in turn.

13. a kind of reclaiming devices realizing discarded object in flue gas purifying method according to any one of claim 10 ~ 12, it is characterized in that: between described one-level solid-liquid separating equipment and sodium nitrate crystallizer, be provided with heat exchanger, the medium inlet end of described heat exchanger is connected with one-level filtrate (liquid, secondary filtrate (liquid respectively; Then being connected with at the media outlet end of described heat exchanger supplies one-level filtrate be delivered to the one-level filtrate conduit (10) of sodium nitrate crystallizer and be delivered to the secondary filtrate conduit (11) of waste water evaporimeter for secondary filtrate.