CN105709597B - A kind of the flue gas ash removal mercury removal device and its processing method of plasma reactor joint membrane bag filter - Google Patents

Abstract

The invention provides a flue gas dust removal and mercury removal device with a plasma reactor combined with a film-coated filter bag and a processing method thereof. The device is a two-stage structure, including a plasma reactor and a bag filter, and a plasma reaction The filter is connected to the bag filter through the air inlet pipe, and the bag filter has a built-in film filter bag. The invention combines the plasma with the film-coated filter bag, uses the action of the plasma to charge and coagulate the dust in the flue gas, and at the same time, the oxygen-containing free radicals in the plasma can oxidize the elemental mercury, and then the gas passes through When covering the filter bag, on the one hand, it can remove dust, on the other hand, the mercury removal catalyst on the filter bag can further oxidize and remove elemental mercury, and the oxygen free radicals generated by the plasma can also improve the activity of the catalyst, thereby improving the Removal efficiency of fine particulate matter and elemental mercury.

Description

A flue gas dedusting and mercury removal device with a plasma reactor combined with a film-coated filter bag and its Approach

technical field

The invention belongs to the field of flue gas purification, and relates to a flue gas dust removal and mercury removal device and a processing method thereof, in particular to a flue gas dust removal and mercury removal device with a plasma reactor combined with a film-coated filter bag and a processing method thereof.

Background technique

In coal-fired power plants and petrochemical fields, a large amount of dust, SO _x , NO _x or heavy metals and other pollutants will be produced during the combustion process. In recent years, with the improvement of environmental protection regulations and the enhancement of people's awareness of environmental protection, fine particulate matter and heavy metal pollutants have received great attention from researchers at home and abroad because of their great harm to the environment and human body. In order to increase environmental protection and improve the environment, the newly released boiler air pollutant emission standard on May 16, 2014 stipulates that the maximum emission concentration standard for new coal-fired boiler particulate matter is 50mg/m ³ , and the emission standard for key areas is 30mg/m ³ , and the emission standard of elemental mercury is also reduced to 0.05mg/m ³ . Fine particulate matter mainly refers to solid particles with an aerodynamic equivalent diameter of ≤10 μm. Due to the small particle size, the specific surface area is greatly increased, and it is easy to become the carrier or reactant of other toxic and harmful substances (such as acid oxides, toxic heavy metals, etc.). Fine particulate matter is very harmful to the environment and human health. Studies have shown that fine particulate matter, especially PM2.5, has an important impact on the reduction of atmospheric visibility. Compared with coarse particulate matter, fine particulate matter (PM2.5) has the ability to reduce visibility. Stronger, is the main cause of haze weather. In addition, particles smaller than 10um can enter the lungs through the nose, causing respiratory and lung diseases.

For the removal of particulate matter in the flue gas, there are many types of dust collectors in the industry, such as the existing industrial dust removal technologies such as cyclone dust collectors and bag dust collectors, which have poor removal effects on fine particles, while electrostatic precipitators and wet dust collectors It is difficult for a dust collector to capture fine dust particles of 0.1-1 μm. Therefore, for the removal of fine particles in the industry, researchers have proposed a variety of new high-efficiency dust removal technologies, such as the promotion and improvement of low-pressure drop high-efficiency electrostatic dust removal, wet electrostatic dust removal technology, electric bag composite dust removal technology and plasma method. The method of fine particles to improve the removal efficiency of fine particles.

Mercury in flue gas generally has three forms: particulate mercury, oxidized mercury and elemental mercury. Among them, particulate mercury and oxidized mercury can be removed in subsequent desulfurization devices, and can also be attached to particulate matter and removed by dust removal devices. However, due to the high volatility and low water solubility of elemental mercury, it is difficult to be removed by the above devices , and are discharged into the atmosphere together with the flue gas, causing environmental pollution.

CN 101693465A discloses an integrated denitrification and demercury method with adsorption and synergistic plasma action. Nitrogen gas is added to the gas containing nitric oxide and mercury and mixed so that the peak voltage is not lower than 3000 volts and the frequency of the pulse power supply is not lower. The high-frequency and high-voltage electric field below 500 Hz realizes simultaneous denitrification and mercury removal. Although this method utilizes the method of adsorbing synergistic plasma, its removal effect on fine particles in the gas to be treated is poor, and the removal effect on elemental mercury is not ideal at the same time.

CN 101716451A discloses a method for removing various pollutants in flue gas by combining discharge plasma and absorption. In the method, after the coal-burning or incineration flue gas is treated by electric dust removal or bag dust removal, it passes through the pre-washing tower, the primary discharge plasma reactor, the primary absorption tower, the secondary discharge plasma reactor and the secondary absorption tower in sequence. . The pre-scrubbing tower is used for flue gas pre-purification, cooling and absorption liquid concentration; the primary discharge plasma reactor is used for NO oxidation and fine particle charging, trapping and removal; the primary absorption tower is used for SO ₂ , NO _x and charge Electric fine particles are washed and removed; the secondary discharge plasma reactor is used for the oxidation of elemental Hg and the charging and trapping of acid mist and ammonium mist; the secondary absorption tower is used for the washing and removal of oxidized Hg and other pollutants remove. However, this method has a poor removal effect on fine particulate matter, especially PM2.5, and the elemental mercury in it is also difficult to remove, and is emitted into the atmosphere together with the flue gas.

Contents of the invention

Aiming at the above-mentioned problems in the prior art that fine particles with a particle size of less than 10um in the flue gas and elemental mercury are difficult to remove, the present invention provides a flue gas dust removal and mercury removal device with a plasma reactor combined with a film-coated filter bag and its treatment method. The method combines the plasma with the film-coated filter bag, and uses the action of the plasma to charge and coagulate the dust in the flue gas, and at the same time, the oxygen-containing free radicals in the plasma can oxidize the elemental mercury, and then the gas is When passing through the film-coated filter bag of the bag filter, on the one hand, it can remove fine dust, on the other hand, the mercury removal catalyst on the filter bag can further oxidize and remove elemental mercury, and the oxygen free radicals generated by the plasma can improve the catalyst. active. The device and treatment method of the invention can greatly improve the removal efficiency of fine particles and the oxidation removal efficiency of elemental mercury, and reduce the energy consumption of plasma and the wear of filter bags.

For reaching this purpose, the present invention adopts following technical scheme:

In the first aspect, the present invention provides a flue gas dedusting and mercury removal device, the device includes a plasma reactor and a bag filter, the plasma reactor and the bag filter are connected through an inlet pipe, and the bag filter has Covered filter bags.

In the present invention, the plasma in the plasma reactor has a better charging and coagulation effect on fine particles with a diameter less than 10um. When the flue gas passes through the plasma reactor, in the plasma environment, the particles in the flue gas will Heteropolar charges are generated. Because the particles carry heterogeneous charges, under the action of electric field force and Coulomb force, fine particles continue to undergo thermal motion and collide to produce condensation, especially some ultrafine particles can reach the surface of fly ash in the form of electrophoresis and adhere The large particles are then removed, and a large number of active free radicals will be generated in the plasma reactor, which can oxidize elemental mercury, and the oxygen free radicals generated by the plasma can improve the catalyst activity in the subsequent process.

In the present invention, the film-coated filter bag adheres to the polytetrafluoroethylene layer loaded with catalyst, which can further remove fine dust and elemental mercury, has high removal efficiency of fine dust and elemental mercury, and can reduce plasma energy consumption.

The size of the plasma reactor and the bag filter in the present invention can be adjusted according to the amount of flue gas to be treated.

As a preferred version of the present invention, the plasma reactor is a line-plate structure, and the line-plate structure can facilitate the collection of particles.

As a preferred solution of the present invention, the plasma reactor includes an electrode, which is a high-voltage electrode, and its voltage is 0-100KV and does not include 0.

Preferably, the electrodes are connected to a power source.

Preferably, the power supply is a high-frequency power supply, and the high-frequency power supply refers to a power supply with a frequency range of more than 100KHz. The use of high-frequency electrodes has higher power conversion efficiency and better charge intensity.

Preferably, the power supply is any one of AC and DC power supply, pulse power supply or radio frequency power supply.

Preferably, the outer wall of the plasma reactor is connected to a ground wire.

As a preferred solution of the present invention, the bag filter also includes a clean air chamber, which is located at the outlet of the film-coated filter bag, and the flue gas purified by the film-coated filter bag is collected in the clean air chamber, and then passed through The outlet pipe of the bag filter is discharged outside.

As a preferred solution of the present invention, the film-coated filter bag uses polyimide fiber and/or polytetrafluoroethylene material as the base cloth material, and a catalyst-loaded polytetrafluoroethylene layer is adhered to the base cloth material.

Preferably, the catalyst is a mercury removal catalyst.

Preferably, the mercury removal catalyst is Mn-Ce/TiO ₂ catalyst, but not limited to Mn-Ce/TiO ₂ catalyst, especially catalysts that can perform mercury removal catalysis are also suitable for the present invention, but Mn-Ce/TiO The TiO ₂ catalyst has the best effect. The mercury removal catalyst can lower the reaction temperature and has higher mercury removal ability.

In a second aspect, the present invention provides a treatment method for the above-mentioned flue gas dedusting and mercury removal device, the method is:

The flue gas to be treated is firstly treated by plasma to remove dust particles and preliminary mercury removal, then carry out dust removal with film-coated filter bags and further catalyze mercury removal, and finally obtain purified flue gas.

As a preferred solution of the present invention, the plasma treatment is performed in a plasma reactor.

Preferably, the processing voltage of the plasma treatment is 0-100KV and does not include 0, such as 5kV, 10kV, 30kV, 50kV, 70kV or 100kV, etc., but it is not limited to the listed values, and other values within the listed range are feasible.

As a preferred solution of the present invention, the dust removal of the film-coated filter bag is carried out in a bag filter.

As a preferred solution of the present invention, the catalyst used in the film-coated filter bag dust removal is a mercury removal catalyst.

Preferably, the mercury removal catalyst is a Mn-Ce/TiO ₂ catalyst.

Preferably, the dust removal temperature of the film-coated filter bag is 150-300°C, such as 150°C, 170°C, 200°C, 230°C, 250°C, 270°C or 300°C, etc., but not limited to the listed values, Other values within the listed ranges are possible.

As a preferred version of the present invention, the method is:

The flue gas to be treated first enters the plasma reactor, and after plasma treatment to remove dust particles and preliminary mercury removal, it enters the bag filter for dust removal and further catalytic mercury removal, and finally the purified flue gas .

In the present invention, the flue gas to be treated enters the plasma reactor first, and in the plasma reactor, in order to charge the dust, a large amount of gas ions must first be obtained. Under the action of an external high-voltage electric field, in the plasma reactor, gas molecules ionize electrons and ions, and the generated high-energy electrons collide with other gas molecules, the gas ionization intensifies, and then an electron avalanche occurs, producing a large number of charged particles. The entire reaction The organ finally contains a large number of high-energy electrons, ions and free radicals. Under the action of an electric field, the charged particles are charged due to the chaotic thermal motion and the collision of the dust during diffusion. Plasma makes passing dust carry different (positive and negative) charges, attracts itself under the action of Coulomb force, and condenses into large particles. Effective collection of fine particulate matter. After the dust is charged, it moves like a dust collecting plate under the action of an electric field, and when it reaches the electrode plate, it releases the charge and deposits it. In addition, because a large number of active free radicals are generated in the plasma, a series of chemical reactions can occur, and the elemental mercury can be effectively oxidized and removed.

After plasma treatment to remove dust particles and preliminary mercury removal, it enters the bag filter for dust removal with film-coated filter bags. The base cloth material inside the film-coated filter bags can further effectively remove particulate matter in the flue gas, and then the flue gas The catalyst-loaded polytetrafluoroethylene layer can effectively oxidize and remove the remaining elemental mercury in the flue gas, and achieve simultaneous and efficient removal of fine particles and elemental mercury to meet environmental protection requirements.

Compared with the prior art, the present invention has the following beneficial effects:

The invention combines the plasma with the film-coated filter bag, uses the action of the plasma to charge and coagulate the dust in the flue gas, and at the same time, the oxygen-containing free radicals in the plasma can oxidize the elemental mercury, and then the gas passes through When covering the filter bag, on the one hand, it can remove dust, on the other hand, the mercury removal catalyst on the filter bag can further oxidize and remove elemental mercury, and the oxygen free radicals generated by the plasma can also improve the activity of the catalyst and make the flue gas The removal efficiency of fine particles in the plasma is over 99%, and the removal efficiency of elemental mercury is over 95%, and the plasma energy consumption is reduced by about 20% compared with the prior art.

Description of drawings

Fig. 1 is the structural representation of flue gas dedusting and mercury removal device of the present invention;

Fig. 2 is the structural representation of the plasma reactor in the flue gas dedusting and mercury removal device;

Fig. 3 is the sectional view of the A-A section of plasma reactor;

Fig. 4 is a schematic structural view of a film-coated filter bag in a flue gas dedusting and mercury removal device;

Among them, 1-intake pipe, 2-plasma reactor, 3-bag filter, 4-outlet pipe, 5-electrode, 6-power supply, 7-grounding wire, 8-base cloth material, 9-PTFE Vinyl layer, 10-air inlet, 11-coated filter bag, 12-clean air chamber, 13-air outlet.

Detailed ways

Below in conjunction with several specific embodiments, illustrate and help to further understand the present invention, but the specific details of embodiment are only in order to illustrate the present invention, do not represent all technical solutions under the present invention conceive, therefore should not be interpreted as to the present invention generally The technical solution defines that some insubstantial changes that do not deviate from the inventive concept in the eyes of a skilled person, such as simple changes or replacements with technical features having the same or similar technical effects, all fall within the protection scope of the present invention.

As shown in Figures 1, 2 and 3, the present invention provides a flue gas dedusting and mercury removal device, which includes a plasma reactor 2 and a bag filter 3, and the plasma reactor 2 and the bag filter 3 pass through The air inlet pipe 1 is connected, and the bag filter 3 has a built-in film filter bag 11 .

Described plasma reactor 2 is wire-plate structure, comprises electrode 5, and electrode can be various shapes such as zigzag etc., and electrode 5 is connected with power supply 6, and power supply 6 is high-frequency power supply, and further is AC-DC power supply, pulse power supply or Any kind of RF power supply.

The outer wall of the plasma reactor 2 is connected to the ground wire 7 .

The bag filter 3 also includes a clean air chamber 12 located at the outlet of the film-coated filter bag 11 , the clean air chamber 12 is connected to the air outlet pipe 4 , and the air outlet pipe 4 is connected to the air outlet 13 .

The film-coated filter bag 11 uses polyimide fiber and/or polytetrafluoroethylene material as the base cloth material 8, and the polytetrafluoroethylene layer 9 loaded with catalyst is adhered on the base cloth material 8, and the structure is as shown in Figure 4 Shown; The catalyst is a mercury removal catalyst; The mercury removal catalyst is a Mn-Ce/TiO ₂ catalyst.

Example 1:

This embodiment provides the following flue gas dedusting and mercury removal device:

The device is a two-stage structure, including a plasma reactor 2 and a bag filter 3, the plasma reactor 2 and the bag filter 3 are connected through the intake pipe 1, and the bag filter 3 has a built-in film filter bag 11 .

The plasma reactor 2 has a wire-plate structure and includes an electrode 5 connected to an AC and DC power supply 6 , and the outer wall of the plasma reactor 2 is connected to a ground wire 7 .

The shown bag filter 3 also includes a clean air chamber 12 located at the outlet of the film-coated filter bag 11 , the clean air chamber 12 is connected to the air outlet pipe 4 , and the air outlet pipe 4 is connected to the air outlet 13 .

The film-coated filter bag 11 uses polyimide fiber material as the base cloth material 8, and on the base cloth material 8, adheres the polytetrafluoroethylene layer 9 loaded with catalyst, and the catalyst is Mn-Ce/TiO _Catalyst .

The above-mentioned device is used to treat the simulated flue gas. The content of fine particles in the simulated flue gas is 5g/m ³ , and the content of elemental mercury is 20ug/m ³ . The treatment method is as follows:

The simulated flue gas to be treated enters the plasma reactor 2 through the air inlet 10, and the high-voltage electrode of the plasma reactor 2 and the reactor form a high-voltage electric field with a voltage of 50KV, which ionizes the gas and contains a large amount of charged particles. When the fine particles pass through the electric field, they are charged with different charges through electric field charging and diffusion charging. Under the action of the electric field, the charged particles are continuously agglomerated into larger-sized soot particles, and at the same time, some active oxygen radicals are generated in the plasma to oxidize the flue gas. The elemental mercury in the air, after plasma treatment to remove dust particles and preliminary mercury removal, the flue gas enters the film-coated filter bag 11 in the bag filter 3 through the intake pipe 1, and passes through the polyimide filter bag 11. The fiber base cloth material 8 can further filter the fine dust in the flue gas, and the elemental mercury in the flue gas is oxidized and removed through the polytetrafluoroethylene layer 9 loaded with Mn-Ce/TiO ₂ catalyst. The temperature of filter bag dedusting is 200°C, and then the flue gas is discharged from the device through the clean gas chamber 12, the gas outlet pipe 4 and the gas outlet 13.

The content of fine particulate matter in the final treated flue gas is 10-30mg/m ³ , and the content of elemental mercury is 0.8-2ug/ ^m3 , that is, the removal efficiency of particulate matter is over 99%, and the removal efficiency of elemental mercury is over 90%. , and reduces the energy consumption of the plasma by about 20% compared with the prior art.

Example 2:

In the device used in this embodiment, except that the power supply 6 is a pulse power source, other components and connection methods of the device are the same as those in Embodiment 1.

The flue gas dedusting and mercury removal device is used to process the simulated flue gas, except that the high-voltage electrode of the plasma reactor 2 and the reactor form a voltage of 50KV, and the temperature of the film-coated filter bag dust removal is 300 ° C, the processing method is the same as that of Example 1 In the same way, the content of fine particulate matter in the final treated flue gas is 10-30mg/m ³ , and the content of elemental mercury is 0.6-1.5ug/ ^m3 , that is, the removal efficiency of particulate matter is over 99%, and the removal efficiency of elemental mercury The efficiency is more than 92%, and the plasma energy consumption is reduced by about 25% compared with the prior art.

Example 3:

The devices and connection methods used in this embodiment are the same as those in Embodiment 1.

The flue gas dust removal and mercury removal device is used to process the simulated flue gas, except that the high-voltage electrode of the plasma reactor 2 and the reactor form a voltage of 100KV, and the temperature of the film-coated filter bag dust removal is 150 ° C, the treatment method is the same as that of Example 1 In the same way, the content of fine particulate matter in the final treated flue gas is 10-30mg/m ³ , and the content of elemental mercury is 0.6-1.5ug/ ^m3 , that is, the removal efficiency of particulate matter is over 99%, and the removal efficiency of elemental mercury The efficiency is more than 93%, and the energy consumption of the plasma is reduced by about 22% compared with the prior art.

Comparative example 1:

This comparative example only uses the plasma reactor 2 to process the simulated flue gas, the content of the simulated flue gas is the same as in Example 1, the structure and treatment process of the plasma reactor 2 are the same as in Example 1, and finally after the treatment The content of fine particulate matter in the final flue gas is 0.8g/m ³ , and the content of elemental mercury is 4.5ug/m ³ , that is, the removal efficiency of particulate matter is about 85%, and the removal efficiency of elemental mercury is about 75%.

Comparative example 2:

In this comparative example, only the bag filter 3 is used to process the simulated flue gas, the content of the simulated flue gas is the same as in Example 1, the structure and treatment process of the bag filter 3 are the same as in Example 1, and finally after treatment The content of fine particulate matter in the final flue gas is 0.1g/m ³ , and the content of elemental mercury is 6.5ug/m ³ , that is, the removal efficiency of particulate matter is about 95%, and the removal efficiency of elemental mercury is about 65%.

Based on the results of Examples 1-3 and Comparative Examples 1-2, it can be seen that the present invention combines plasma with a film-coated filter bag, and uses the action of plasma to charge and condense the dust in the flue gas, At the same time, the oxygen-containing free radicals in the plasma can oxidize elemental mercury, and then when the gas passes through the film-coated filter bag, on the one hand, it can remove fine dust, and on the other hand, the mercury removal catalyst on the filter bag can further oxidize and remove elemental mercury , and the oxygen free radicals generated by the plasma can also improve the activity of the catalyst, so that the removal efficiency of the fine particles in the flue gas is over 99%, the removal efficiency of the elemental mercury is over 92%, and the energy consumption of the plasma is compared with the existing There are techniques that reduce around 20%.

The applicant declares that the present invention illustrates the detailed methods of the present invention through the above-mentioned examples, but the present invention is not limited to the above-mentioned detailed methods, that is, it does not mean that the present invention must rely on the above-mentioned detailed methods to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (14)

1. a kind of flue gas ash removal mercury removal device, which is characterized in that described device is two-part structure, including plasma reactor (2) it is connected with sack cleaner (3), plasma reactor (2) with sack cleaner (3) by air inlet pipe (1), bag-type dusting Membrane bag filter (11) built in device (3)；

The plasma reactor (2) includes electrode (5), and the electrode (5) is connected with power supply (6), and the power supply (6) is height Frequency power, the high frequency electric source refer to power supply of the supply frequency range in more than 100KHz；

Wherein, the membrane bag filter (11) is using polyimide fiber and/or polytetrafluoroethylene material as scrim material (8), Adherency load has the polytetrafluoroethylene ethylene layer (9) of catalyst in scrim material (8)；

The catalyst is demercuration catalyst.

2. flue gas ash removal mercury removal device according to claim 1, which is characterized in that the plasma reactor (2) is Line plank frame.

3. flue gas ash removal mercury removal device according to claim 1, which is characterized in that the power supply (6) for power of alterating and direct current, Any one in the pulse power or radio-frequency power supply.

4. flue gas ash removal mercury removal device according to claim 1, which is characterized in that the plasma reactor (2) Outer wall is connected with ground wire (7).

5. flue gas ash removal mercury removal device according to claim 1, which is characterized in that the sack cleaner (3) further includes Air-purifying chamber (12), air-purifying chamber (12) is positioned at the exit of membrane bag filter (11).

6. flue gas ash removal mercury removal device according to claim 1, which is characterized in that the demercuration catalyst is Mn-Ce/ TiO₂Catalyst.

7. according to the processing method of claim 1-6 any one of them flue gas ash removal mercury removal devices, which is characterized in that the side Method is：

Pending flue gas first it is plasma-treated removing dust particle and preliminary demercuration after, carry out membrane bag filter dedusting go forward side by side One step is catalyzed demercuration, finally obtains purified flue gas.

8. processing method according to claim 7, which is characterized in that the corona treatment is in plasma reactor (2) it is carried out in.

9. processing method according to claim 7, which is characterized in that the processing voltage of the corona treatment for 0~ 100KV and not include 0.

10. processing method according to claim 7, which is characterized in that the membrane bag filter dedusting is in sack cleaner (3) Middle progress.

11. processing method according to claim 7, which is characterized in that used catalyst is in the membrane bag filter dedusting Demercuration catalyst.

12. processing method according to claim 11, which is characterized in that the demercuration catalyst is Mn-Ce/TiO₂Catalysis Agent.

13. processing method according to claim 7, which is characterized in that the temperature of the membrane bag filter dedusting for 150~ 300℃。

14. processing method according to claim 7, which is characterized in that the method is：

Pending flue gas is introduced into plasma reactor (2), and plasma-treated removing dust particle takes off with preliminary After mercury, membrane bag filter dedusting is carried out into sack cleaner (3) and is further catalyzed demercuration, finally obtains purified cigarette Gas.