阅读说明：本技术 脱除烟气重金属污染物的改性高岭土喷射系统及其方法 (Modified kaolin injection system and method for removing heavy metal pollutants in flue gas ) 是由 唐玉婷 丁思淳 陈晓斌 孙勇 马晓茜 于 2019-11-19 设计创作，主要内容包括：本发明公开了脱除烟气重金属污染物的改性高岭土喷射系统及其方法。所述喷射系统包括改性单元和喷射单元,改性单元包括混合器、给料器、干燥器、引风机、旋风分离器和振动料斗,混合器的一侧设置高岭土和腐殖酸入口,混合器的另一侧通过给料器连接至干燥器；干燥器连接至旋风分离器的入口,旋风分离器顶部的气体出口连接引风机,旋风分离器的底端出口连接至振动料斗；喷射单元包括进料器、气固混合加速器、罗茨风机和具有喷口的喷射管道,振动料斗与气固混合加速器之间设置进料器,罗茨风机和喷射管道连接至气固混合加速器的两端,罗茨风机将气固混合加速器中的物料吹入喷射管道。改性单元以及喷射单元配合运行,保证整个过程的封闭、连续、安全。(The invention discloses a modified kaolin injection system and a method for removing heavy metal pollutants in flue gas. The spraying system comprises a modification unit and a spraying unit, the modification unit comprises a mixer, a feeder, a dryer, an induced draft fan, a cyclone separator and a vibration hopper, one side of the mixer is provided with kaolin and humic acid inlets, and the other side of the mixer is connected to the dryer through the feeder; the dryer is connected to an inlet of the cyclone separator, a gas outlet at the top of the cyclone separator is connected with the induced draft fan, and an outlet at the bottom end of the cyclone separator is connected to the vibration hopper; the injection unit comprises a feeder, a gas-solid mixing accelerator, a Roots blower and an injection pipeline with a nozzle, the feeder is arranged between the vibration hopper and the gas-solid mixing accelerator, the Roots blower and the injection pipeline are connected to two ends of the gas-solid mixing accelerator, and the Roots blower blows materials in the gas-solid mixing accelerator into the injection pipeline. The modification unit and the injection unit are matched to operate, so that the whole process is closed, continuous and safe.)

1. The modified kaolin injection system for removing heavy metal pollutants in flue gas is characterized by comprising a modification unit and an injection unit, wherein the modification unit comprises a mixer (5), a feeder (6), a dryer (7), an induced draft fan (8), a cyclone separator (9) and a vibration hopper (10), one side of the mixer (5) is provided with a kaolin and humic acid inlet, and the other side of the mixer (5) is connected to the dryer (7) through the feeder (6); the dryer (7) is connected to an inlet of the cyclone separator (9), a gas outlet at the top of the cyclone separator is connected with the induced draft fan (8), so that materials in the dryer (7) are sucked into the cyclone separator (9) through the induced draft fan (8), and an outlet at the bottom end of the cyclone separator (9) is connected to the vibration hopper (10); the injection unit comprises a feeder (11), a gas-solid mixing accelerator (12), a Roots blower (13) and an injection pipeline (15) with a nozzle, wherein the feeder (11) used for controlling the amount of materials entering the gas-solid mixing accelerator (12) is arranged between a vibration hopper (10) and the gas-solid mixing accelerator (12), the Roots blower (13) and the injection pipeline (15) are connected to two ends of the gas-solid mixing accelerator (12), and the Roots blower (13) blows the materials in the gas-solid mixing accelerator (12) into the injection pipeline (15).

2. The system according to claim 1, wherein the modifying unit further comprises an extractor and a centrifugal pump (4), the extractor comprises a precession extrusion unit (1), a storage chamber (2) and a waste chamber (3), the precession extrusion unit (1) is positioned above the storage chamber (2), holes are arranged on the side wall of the precession extrusion unit (1), the precession extrusion unit (1) is connected with the waste chamber (3) through a pipeline, alkali liquor and humus soil are connected above the precession extrusion unit (1), the acid liquor is connected to the storage chamber (2), and an outlet of the storage chamber (2) is connected to the mixer (5) through the centrifugal pump (4) so as to introduce the humus acid into the mixer (5).

3. System according to claim 1, characterized in that three rotatable rollers are arranged in the mixer (5), offset from each other, with blades on the rollers.

4. The system according to claim 3, wherein the injection unit further comprises a check valve and an air compressor (16), the check valve being disposed between the gas-solid mixing accelerator (12) and the injection pipe (15), and between the air compressor (16) and the injection pipe (15); the injection system further comprises an electronic control system (17), wherein the electronic control system (17) is electrically connected with the injection unit and the power utilization unit of the improvement unit.

5. The system according to claim 1, characterized in that the injection unit further comprises a blow valve (14), the blow valve (14) is arranged between the roots blower (13) and the gas-solid mixing accelerator (12); the draught fan (8) is also connected with a pipeline between the gas-solid mixing accelerator (12) and the injection pipeline (15).

6. The system according to claim 1, characterized in that the centrifugal pump (4), the extractor, the mixer (5), the dryer (7) and the transfer piping are made of stainless steel material; the extractor and the mixer (5) are both provided with heating units and wrapped with heat insulation materials.

7. The system according to claim 1, characterized in that the modification unit further comprises a water storage tank (19), the liquid outlet of the dryer (7) being connected to the water storage tank (19); a precession stirring unit is arranged in the dryer (7); the vibration hopper (10) is provided with a vibration unit.

8. The method for removing heavy metal pollutants in flue gas by using the injection system as claimed in any one of claims 1 to 7, wherein humic acid and kaolin are fully mixed in the mixer (5) to obtain modified kaolin, the injection system generates negative pressure by using the induced draft fan (8), the modified kaolin dried in the dryer (7) is sucked into the cyclone separator (9), and the modified kaolin is separated and then enters the vibration hopper (10); the feeder (11) controls the modified kaolin in the vibration hopper (10) to quantitatively enter the gas-solid mixing accelerator (12); the modified kaolin is blown into the injection pipeline (15) in the flue gas pipeline (20) by the Roots blower (13), and then is uniformly injected into the flue gas pipeline (20) by the injection pipeline (15).

9. The method according to claim 8, characterized in that the water in the water storage tank (19) is heated by the flue gas in the flue gas duct (20) and then enters the dryer (7) to dry the modified kaolin; the temperature of the dryer (7) is controlled between 110 ℃ and 120 ℃, and the drying time of the material is not less than 12 h.

10. The method according to claim 8, characterized in that the humic acid is mixed with alkali liquor in a precession extrusion unit (1), the precession extrusion unit (1) is used for precession extrusion of the material, the dissolved humic acid is extruded into a storage chamber (2) through small holes on the side wall of the precession extrusion unit (1), the remaining humic acid in the precession extrusion unit (1) is conveyed to a waste material chamber (3) through a pipeline, the acid liquor is used for adjusting the pH value in the storage chamber (2), and then the humic acid is conveyed into a mixer (5) through a centrifugal pump (4), and the mass ratio of the humic acid solution to the kaolin in the mixer (5) is 1: 10-1: 30.

Technical Field

The invention belongs to the technical field of removal of heavy metal pollutants in flue gas, and particularly relates to a modified kaolin injection system and a method for removing the heavy metal pollutants in the flue gas.

Background

Coal, as a substance consisting of complex elements, generates a large amount of toxic and harmful substances after combustion, including heavy metals such as mercury, arsenic, lead, cadmium, chromium, and the like. The household garbage also has complex components, and SO is generated in the incineration process _X、NO _XAnd common pollutants such as CO and HCl can also generate dioxin and heavy metal with strong toxicity. These heavy metals produced are mainly concentrated on submicron particles (PM 1, i.e. aerodynamic diameter ≦ 1 μm) and are difficult to effectively capture by conventional atmospheric pollutant treatment facilities. Heavy metals in the flue gas mainly stay in the atmosphere in the form of aerosol, are difficult to degrade, and can be continuously accumulated in the natural environment and biological organisms, thereby possibly causing serious environmental pollution and disease threats. Mercury released during the coal burning process is mainly emitted into the atmosphere in gaseous form along with the flue gas. Currently, the researchers generally consider the tail flue gas adsorbent injection technology to be the most promising heavy metal emission control technology. The technology utilizes the adsorbability of the adsorbent to heavy metal elements in the flue gas to lead the heavy metals to be gathered into particles in the adsorbent so as to be captured by subsequent dust removal equipment. The used adsorbents mainly comprise a series of inorganic adsorbents such as activated carbon, fly ash and calcium-based adsorbents, wherein the activated carbon adsorbents have high efficiency of removing heavy metals, but have high cost; although the cost of other mineral adsorbents is low, the adsorption effect on heavy metals is not ideal. Therefore, some cheap adsorbents can be selected and modified to improve the heavy metal removal capacity.

At present, the types of adsorbents found by people are various, and each adsorbent has advantages and disadvantages, and an adsorbent material with strong adsorption capacity and low price is difficult to select, so that the application of a single-material adsorbent has strong limitation. The composite adsorbent well overcomes the defects of a single adsorbent, and integrates the advantages of different adsorbent materials to meet industrial requirements. The composite adsorbent is roughly classified into inorganic/organic adsorbents, inorganic/inorganic adsorbents, and organic/organic adsorbents in terms of material types, wherein the inorganic/organic adsorbents combine the advantages of inorganic and organic materials, and the preparation cost of the adsorbents is reduced while the adsorption capacity is improved. The kaolin is a natural clay mineral resource widely existing in nature, can adsorb and remove heavy metals in smoke after effective modification, and is a cheap and good alternative adsorbent. Humic acid is a high molecular polymer widely existing in soil, has rich hydroxyl and carboxyl, and has strong adsorbability and complexation on heavy metal ions.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention provides the modified kaolin injection system and the method for removing the heavy metal pollutants in the flue gas. In addition, each link in the system realizes real-time monitoring of the electric control device, the whole flue gas treatment process is simple to operate, safe and reliable, and the working efficiency of workers is greatly improved.

The invention is realized by adopting at least one of the following technical schemes.

The modified kaolin injection system for removing heavy metal pollutants in flue gas comprises a modification unit and an injection unit, wherein the modification unit comprises a mixer, a feeder, a dryer, an induced draft fan, a cyclone separator and a vibration hopper, one side of the mixer is provided with a kaolin and humic acid inlet, and the other side of the mixer is connected to the dryer through the feeder; the dryer is connected to an inlet of the cyclone separator, a gas outlet at the top of the cyclone separator is connected with the induced draft fan, so that materials in the dryer are sucked into the cyclone separator through the induced draft fan, and an outlet at the bottom end of the cyclone separator is connected to the vibration hopper; the injection unit comprises a feeder, a gas-solid mixing accelerator, a Roots blower and an injection pipeline with a nozzle, the feeder for controlling the amount of materials entering the gas-solid mixing accelerator is arranged between the vibration hopper and the gas-solid mixing accelerator, the Roots blower and the injection pipeline are connected to two ends of the gas-solid mixing accelerator, the Roots blower blows the materials in the gas-solid mixing accelerator into the injection pipeline, and the injection pipeline is provided with the nozzle.

Further, the modified unit still includes extractor and centrifugal pump, and the extractor is including precession extrusion unit, apotheca and waste material room, and precession extrusion unit is located the top of apotheca, sets up the hole on the precession extrusion unit lateral wall, and precession extrusion unit passes through the pipeline with the waste material room and links to each other, and alkali lye and humus soil are connected to precession extrusion unit top, and the acidizing fluid is connected to the apotheca, thereby the apotheca export is connected to the blender through the centrifugal pump and is introduced the humic acid in the blender.

Furthermore, three rotatable rollers are arranged in the mixer and are distributed in a vertically staggered manner, and the rollers are provided with blades.

Further, the injection unit further comprises a standby air compressor, and when the pressure loss at the two ends of the gas-solid mixture conveying pipeline exceeds a limit value, namely the wind speed of the roots blower exceeds the requirement of the system, the roots blower 20 is replaced by the standby air compressor with smaller wind volume.

Further, the injection unit also comprises a check valve and an air compressor, wherein the check valve is arranged between the gas-solid mixing accelerator and the injection pipeline and between the air compressor and the injection pipeline; the injection system further comprises an electric control system which is electrically connected with the injection unit and the electricity utilization unit of the improvement unit. The air compressor belongs to a system protection device and is also used for blowing blockage when a spraying pipeline is blocked, and before the blowing blockage starts, the electric control system can automatically suspend the operation of the spraying system. The check valve belongs to a system protection device, prevents the backflow phenomenon of gas and adsorbent, and ensures the safe operation of the Roots blower and the air compressor.

Further, the injection unit also comprises an emptying valve, and the emptying valve is arranged between the Roots blower and the gas-solid mixing accelerator; the induced draft fan is still connected with the pipeline between gas-solid mixing accelerator and the injection pipeline, namely is connected to the modified kaolin conveying pipeline, and the quality loss of the modified kaolin in the conveying process is prevented.

Furthermore, the injection pipeline is provided with a plurality of nozzles, and a plurality of feeding modes of simultaneous feeding are adopted to ensure the uniform distribution of particles and pressure in the pipeline, so that the modified kaolin is uniformly dispersed in the flue as much as possible, and the pipeline blockage is prevented.

Furthermore, the centrifugal pump, the extractor, the mixer, the dryer and the conveying pipeline are all made of stainless steel materials, so that the corrosion resistance and the wear resistance of the equipment are improved. The extractor and the mixer are both provided with heating units and wrapped with heat insulation materials so as to deal with cold weather and protect the safe operation of the system. In addition, the outside of the infusion pipeline is also wrapped with a heat insulation material to prevent the occurrence of frost cracking.

Further, the modification unit further comprises a water storage tank, and the liquid outlet of the dryer is connected to the water storage tank.

Furthermore, a precession stirring unit is arranged in the dryer, so that the materials are dried uniformly.

Further, the vibration hopper is provided with a vibration unit to prevent the modified kaolin from caking.

According to the method for removing heavy metal pollutants in flue gas by using the jet system, humic acid and kaolin are fully mixed in a mixer to obtain modified kaolin, a draught fan enables the jet system to generate negative pressure, the modified kaolin dried in a dryer is sucked into a cyclone separator, and the modified kaolin is separated and then enters a vibration hopper; the feeder controls the modified kaolin in the vibrating hopper to quantitatively enter the gas-solid mixing accelerator; the modified kaolin is blown into the injection pipeline in the flue gas pipeline by the Roots blower, and then is uniformly injected into the flue by the injection pipeline.

Furthermore, water in the water storage tank is heated by flue gas in the flue gas pipeline and then enters the dryer to dry the modified kaolin, so that the flue gas is prevented from directly entering the dryer pipeline to cause blockage, the maintenance cost is further increased, water resources are saved, the energy utilization rate is increased, and the smoke exhaust temperature is reduced.

Further, the temperature of the dryer is controlled between 110 ℃ and 120 ℃, and the drying time of the material is not less than 12 hours.

Further, mixing humic acid and alkali liquor in a precession extrusion unit, carrying out precession extrusion on the materials by the precession extrusion unit, extruding dissolved humic acid into a storage chamber through small holes in the side wall of the precession extrusion unit, conveying the residual humic acid in the precession extrusion unit to a waste chamber through a pipeline, adjusting the pH value in the storage chamber by using acid liquor, and then conveying the humic acid into a mixer through a centrifugal pump, wherein the mass ratio of the humic acid solution to the kaolin in the mixer is 1: 10-1: 30.

The feeder controls humic acid modified kaolin in the hopper to enter the gas-solid mixing accelerator according to a certain proportion, and the feeding speed of the feeder is consistent with that of the kaolin so as to ensure that the whole spraying system continuously and reliably runs.

The modification unit relates to preparation of humic acid, feeding and modification of kaolin and aggregate; the injection unit relates to the mixing of the modified kaolin and air and the injection in the flue.

Compared with the prior art, the invention has the following advantages that: the system mainly aims at removing heavy metal pollutants such as mercury, arsenic, lead, cadmium, chromium and the like in flue gas of coal-fired power plants and waste incineration power plants. The modification unit and the injection unit are matched to operate, so that the whole process is closed, continuous and safe. High-temperature flue gas is used for providing heat in the drying process, so that the energy utilization rate is improved, and the smoke exhaust temperature is reduced; and in the drying process, water obtained by drying is used as a circulating heating medium, so that water resources are saved. The whole system is monitored by the electric control system, the response is rapid, the control precision is high, the operation is simple and convenient, and the working efficiency is high. The hopper for storing the modified kaolin is a vibration hopper, so that the modified kaolin is prevented from caking in the storage process. The equipment contacting with corrosive substances adopts corrosion-resistant stainless steel, so that the service life and the safety of the equipment are improved. The long-time stable operation of the injection pipeline is ensured by the feeding mode of feeding at multiple positions simultaneously, and the uniformity of the adsorbent in the flue is ensured.

Drawings

FIG. 1 is a process flow diagram of the modified kaolin injection system for removing heavy metal pollutants from flue gas of the present invention.

Wherein, 1-precessing the extrusion unit; 2-a storage chamber; 3-a waste chamber; 4-a centrifugal pump; 5-a mixer; 6-a feeder; 7-a dryer; 8-induced draft fan; 9-a cyclone separator; 10-vibrating the hopper; 11-a feeder; 12-gas-solid mixing accelerator; 13-Roots blower; 14-an evacuation valve; 15-an injection pipe; 16-an air compressor; 17-an electronic control system; 18-centrifugal water pump; 19-a water storage tank; 20-flue gas pipeline.

Detailed Description

The following further describes embodiments of the present invention in conjunction with the following examples and figures, but the practice of the present invention is not limited thereto.

As shown in the attached figure 1, the invention provides a modified kaolin injection system for removing heavy metal pollutants in flue gas, which mainly comprises a modification unit and an injection unit, wherein the two units are matched to operate, so that the whole process is closed, continuous and safe.

Modified unit includes the extractor, centrifugal pump 4, blender 5, dispenser 6, desicator 7, draught fan 8, cyclone 9 and vibration hopper 10, the extractor is including precession extrusion unit 1, apotheca 2 and waste room 3, precession extrusion unit 1 is located apotheca 2 top, set up the hole on the precession extrusion unit 1 lateral wall, precession extrusion unit 1 links to each other through the pipeline with waste room 3, alkali lye and humus soil are connected to precession extrusion unit 1 top, the acidizing fluid is connected to apotheca 2, thereby 2 exports in apotheca are connected to 5 one side of blender through centrifugal pump 4 and are introduced humic acid into blender 5, and 5 homonymies of blender still set up the kaolin entry, set up three rotatable gyro wheel in the blender 5, upper and lower dislocation distribution, have the blade on the gyro wheel. The other side of the mixer 5 is connected to a dryer 7 through a feeder 6; the material in the dryer 7 is sucked into a cyclone separator 9 through an induced draft fan 8, and the outlet at the bottom end of the cyclone separator 9 is connected to a vibration hopper 10; the injection unit comprises a feeder 11, a gas-solid mixing accelerator 12, a Roots blower 13 and an injection pipeline 15 with a nozzle, the feeder 11 used for controlling the amount of materials entering the gas-solid mixing accelerator 12 is arranged between the vibration hopper 10 and the gas-solid mixing accelerator 12, the Roots blower 13 and the injection pipeline 15 are connected to two ends of the gas-solid mixing accelerator 12, the Roots blower 13 blows the materials in the gas-solid mixing accelerator 12 into the injection pipeline 15, and the injection pipeline 15 is provided with a nozzle. The injection duct 15 is arranged in the flue duct 20.

The air compressor 16 belongs to a system protection device and is used for blowing blockage when the injection pipeline is blocked, and before the blowing blockage starts, the electric control system can automatically suspend the operation of the injection system.

The injection unit also comprises an air release valve 14 and check valves, and the check valves are arranged between the gas-solid mixing accelerator 12 and the injection pipeline 15 and between the air compressor 16 and the injection pipeline 14; the air release valve 14 is arranged between the Roots blower 13 and the gas-solid mixing accelerator 12 and used for adjusting the air quantity required by the conveying pipeline; the draught fan 8 is also connected with a pipeline between the gas-solid mixing accelerator 12 and the injection pipeline 15, namely connected to a modified adsorbent conveying pipeline; the injection pipeline 15 is provided with a plurality of nozzles, a feeding mode of feeding at a plurality of positions simultaneously is adopted, a precession stirring unit is arranged in the dryer 9, the vibration hopper 10 is provided with a vibration unit, the modification unit further comprises a water storage tank 19, and a liquid outlet of the dryer 9 is connected to the water storage tank 19.

The centrifugal pump 4, the extractor, the mixer 5, the dryer 7 and corresponding conveying pipelines are made of stainless steel materials and are corrosion-resistant and wear-resistant. The extractor and the mixer 5 are both provided with heating devices and wrapped with heat insulation materials so as to deal with cold weather and protect the safe operation of the system. In addition, the outside of the infusion pipeline is also wrapped with a heat insulation material to prevent the occurrence of frost cracking.

When the spraying system starts to operate, firstly, humus soil and alkali liquor NaOH are mixed and conveyed in a precession extrusion unit 1, materials are precession extruded by the precession extrusion unit 1, dissolved humic acid is extruded into a storage chamber 2 through small holes on the side wall of the precession extrusion unit 1, the rest materials in the precession extrusion unit 1 are conveyed to a waste material chamber 3 through a pipeline, acid liquor is connected to the storage chamber 2 so as to adjust the pH value of the solution, then an electric control system 17 controls a centrifugal pump 4 to convey the humic acid in the storage chamber 2 into one end of a mixer 5, meanwhile, kaolin is introduced into the mixer 5, the electric control system 17 controls the humic acid solution and the kaolin in the mixer 5 to collide at a high speed in the mixer 5 according to the mass ratio of 1:20, so that the humic acid solution and the kaolin are fully mixed to obtain wet modified kaolin, then the wet modified kaolin is dried in a dryer 7, an induced draft fan 8 is opened, under the action of a draught fan 8, the modified kaolin enters a vibration hopper 10 through a cyclone separator 9 to be stored for later use. The vibration hopper 10 is provided with a vibration device to prevent agglomeration of the modified kaolin. The feeder 11 controls the modified kaolin in the vibrating hopper 10 to enter the gas-solid mixing accelerator 12; under the work of the Roots blower 13, the modified kaolin and air are fully mixed in the gas-solid mixing accelerator 12 and enter the injection pipeline 15 through the conveying pipeline, and the electronic control system controls the injection pipeline 15 to uniformly inject the modified kaolin into the flue 18.

When the pressure loss at the two ends of the gas-solid mixture conveying pipeline exceeds a limit value, namely the wind speed of the Roots blower is far beyond the requirement of the system, the electric control system controls the Roots blower 13 to stop running, and the spare air compressor is replaced to convey the modified kaolin and air into the injection pipeline 15.

The drier 7 provides heat by high-temperature flue gas, dries the modified kaolin, and controls the drying temperature between 110 ℃ and 120 ℃ and the drying time of the materials to be not less than 12 h. The water produced during the drying process is transported to a water tank 19 and is recycled for use in the dryer after being heated by the flue gas in a flue gas duct 20.

Both the check valve and the air compressor 16 are protection devices for the injection system to ensure safe operation of the system. Wherein, the check valve protects the induced draft fan 8 and the air compressor 16; the air compressor 16 performs the blowing and blocking operation of the injection pipeline 15, specifically, when the injection pipeline 15 is blocked, the electronic control system 17 automatically suspends the operation of the injection system, and the air compressor 16 starts to perform the blowing and blocking operation.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any equivalent alterations, modifications or improvements made by those skilled in the art to the above-described embodiments using the technical solutions of the present invention are still within the scope of the technical solutions of the present invention.