CN115253633A - Waste incineration flue gas purification method and system - Google Patents

Abstract

The invention discloses a method and a system for purifying waste incineration flue gas. The flue gas purification method comprises the following steps: carrying out dry deacidification treatment on the waste incineration flue gas; carrying out SCR denitration treatment on the waste incineration flue gas, wherein a catalyst adopted in the SCR denitration treatment comprises a low-temperature catalyst; and performing wet deacidification treatment on the waste incineration flue gas. The flue gas purification system comprises a dry-method deacidification tower (1), an SCR denitration dust removal device (2), a wet-method deacidification tower (4), an induced draft fan (5) and a chimney (6); the smoke inlet of the SCR denitration dust removal device is communicated with the smoke outlet of the dry-method deacidification tower, and the catalyst adopted by the SCR denitration dust removal device comprises a low-temperature catalyst; the smoke inlet of the wet deacidification tower is communicated with the smoke outlet of the SCR denitration dust removal device, and the smoke outlet of the wet deacidification tower is communicated with a chimney. The flue gas purification method and the flue gas purification system do not need to heat the waste incineration flue gas, and the process flow of flue gas purification is simple.

Description

Waste incineration flue gas purification method and system

technical field

The invention relates to a flue gas purification technology, in particular to a waste incineration flue gas purification method and system.

Background technique

At present, the domestic mainstream waste incineration flue gas purification process route is "SNCR denitration treatment → semi-dry deacidification treatment → dry deacidification treatment → activated carbon adsorption treatment → dust removal → GGH heat exchange → SGH heating → SCR denitrification treatment". However, the current waste incineration flue gas purification process route is too complicated, and because the current SCR denitrification treatment still has high requirements for the temperature of waste incineration flue gas, it is necessary for waste incineration flue gas to reach the temperature requirement of 300-350 ° C, but The flue gas temperature after semi-dry deacidification treatment is not high, usually only about 145°C, which cannot meet the flue gas temperature requirements of SCR denitrification treatment, so the waste incineration flue gas has to be heated before SCR denitrification treatment (GGH heat exchange and SGH heating), which leads to a large heat energy consumption in the entire process, which is not conducive to reducing production costs.

The following are the retrieved patent documents related to this field:

Chinese patent (patent number: CN202022060057.4) discloses a hazardous waste incineration flue gas purification system based on a catalytic ceramic fiber filter tube. Chinese patent (patent number: CN202022057185.3) discloses a waste incineration flue gas purification system based on ceramic filter elements and renewable activated carbon. The reaction temperature of the integrated ceramic fiber filter tube device adopted in the above patents is in the range of 300-350°C. The temperature window in this range is not suitable for the adsorption of heavy metals and dioxins by activated carbon. The activated carbon is in a desorption state at a temperature of about 300-350°C. There is no adsorption effect, so for heavy metals and dioxins, it is necessary to set up a separate adsorption device to remove them, which increases the process flow and equipment costs of flue gas treatment.

In addition, some other background technologies or concepts involved in the present invention are further described as follows:

The "SNCR denitrification treatment" mentioned in this article is a denitrification treatment process of the prior art. SNCR is a professional term in this field, which is the abbreviation of "selective non-catalytic reduction" in English, and the Chinese translation is "selective non-catalytic reduction". "Non-catalytic reduction" means that without the action of a catalyst, a reducing agent is sprayed in the temperature range of 800-1000 °C suitable for the denitrification reaction, and the nitrogen oxides in the flue gas are reduced to harmless nitrogen and water.

The "semi-dry deacidification treatment" mentioned herein is a deacidification treatment process in the prior art. Specifically, quicklime is prepared into a lime slurry solution (calcium hydroxide (Ca (OH) ₂ ) solution), and then pressurized to a high-speed rotary atomizer through a lime slurry pump to uniformly inject the rotary atomized solution into the spray reaction tower to react with the flue gas flowing in the tower to remove acid gas.

The "dry deacidification treatment" mentioned in this article is a deacidification treatment process of the prior art. Specifically, the solid deacidification powder is mixed and contacted with the flue gas by spraying, and the deacidification powder Usually, the powder of alkaline substances is used. The dispersed particles of alkaline deacidification powder contact with the acid gas in the flue gas to produce a chemical neutralization reaction to generate neutral salt particles, and then use dust removal equipment to remove the salt particles generated by the reaction. Together with the flue gas dust and unreacted deacidification powder, it is captured, so as to achieve the purpose of removing acid gas in the flue gas.

The "GGH heat exchange" mentioned in this article is a heat exchange process of the prior art. GGH is the abbreviation of "Gas Gas Heater" in English, and the Chinese translation is "flue gas-flue gas heat exchanger". In other words, the GGH heat exchanger of the prior art is used to exchange heat between two flowing media with temperature differences, so that the lower temperature medium is heated and the temperature rises, while the higher temperature medium is cooled and the temperature decreases . The GGH heat exchanger is a device in the prior art. This GGH heat exchanger uses the original flue gas to heat the desulfurized clean flue gas, so that the temperature of the exhaust gas reaches above the dew point, reducing the impact on the flue and the flue gas. Corrosion of the chimney increases the diffusion of pollutants.

The "SGH heating" mentioned in this article is a heating process of the prior art. SGH is the abbreviation of "Steam-Gas-Heater" in English, and the Chinese translation is "steam-gas heat exchanger". In other words, the SGH heat exchanger of the prior art uses steam to exchange heat with flue gas, so that the flue gas with a lower temperature is heated and the temperature rises. The SGH heat exchanger is a device in the prior art. This SGH heat exchanger uses steam to heat the desulfurized clean flue gas to raise the temperature of the flue gas to 300-350°C, which meets the requirements of the conventional SCR denitrification reaction. Temperature range, improve denitrification efficiency.

The "SCR denitration treatment" mentioned in this article is a treatment process of the prior art. SCR is a professional term in this field. It is the abbreviation of "Selective Catalytic Reduction" in English, and the Chinese translation is "Selective Catalytic Reduction The basic principle is that ammonia molecules (NH ₃ ) in ammonia water are used as denitrification reducing agent to react with nitrogen oxides (NO and NO ₂ ) in flue gas to generate harmless nitrogen gas (N ₂ ). Specifically, under the action of a catalyst, the denitrification reducing agent ammonia (NH ₃ ) selectively reduces nitrogen monoxide (NO) and nitrogen dioxide (NO ₂ ) to nitrogen (N ₂ ), and the oxidation reaction between ammonia (NH ₃ ) and oxygen (O ₂ ) hardly occurs, thereby improving the nitrogen selectivity and reducing the consumption of ammonia (NH ₃ ), the denitrification reducing agent. The catalysts used in traditional SCR denitration treatment are usually vanadium-titanium (V-Ti)-based or vanadium-tungsten-titanium (VW-Ti)-based catalysts.

Contents of the invention

The object of the present invention is to provide a method and system for purifying waste incineration flue gas. The flue gas purification method and system do not need to perform additional heat treatment on waste incineration flue gas, thereby avoiding waste of heat energy consumption, and the process flow of flue gas purification Simple, thereby reducing the investment in process equipment.

In order to realize above-mentioned technical purpose, the present invention adopts following technical scheme:

A method for purifying waste incineration flue gas, the method for purifying flue gas comprising:

S1, dry deacidification of waste incineration flue gas;

S2, performing SCR denitration treatment on the waste incineration flue gas, the catalyst used in the SCR denitration treatment includes a low-temperature catalyst;

S3, performing wet deacidification treatment on waste incineration flue gas;

S4, discharging waste incineration flue gas into the atmosphere.

Further, the low-temperature catalyst is a manganese-based catalyst and/or a copper-based catalyst.

Further, cerium and/or zirconium are added to the low-temperature catalyst.

Further, said S2 also includes: spraying activated carbon powder into the waste incineration flue gas during the SCR denitrification process.

Further, said S3 also includes: during the wet deacidification process, using a heat exchanger to exchange heat between the waste incineration flue gas before the wet deacidification treatment and the waste incineration flue gas after the wet deacidification treatment .

A waste incineration flue gas purification system, comprising a dry deacidification tower, an SCR denitrification and dust removal device, a wet deacidification tower, an induced draft fan and a chimney; the smoke inlet of the dry deacidification tower and the smoke exhaust of the waste incinerator The smoke inlet of the SCR denitrification and dust removal device is connected with the smoke outlet of the dry deacidification tower, and the catalyst used in the SCR denitrification and dust removal device includes a low-temperature catalyst; the smoke inlet of the wet deacidification tower It is connected with the smoke outlet of the SCR denitrification and dust removal device, and the smoke outlet of the wet deacidification tower is connected with the smoke inlet of the chimney, and the induced draft fan is arranged at the smoke inlet of the chimney.

Further, the low-temperature catalyst is a manganese-based catalyst and/or a copper-based catalyst.

Further, cerium and/or zirconium are added to the low-temperature catalyst.

Further, an activated carbon powder supply device is provided on the pipeline connected to the smoke inlet of the SCR denitrification and dust removal device.

Further, the flue gas purification system also includes a flow medium heat exchanger; the smoke inlet of the wet deacidification tower communicates with the smoke outlet of the SCR denitrification and dust removal device, which is the smoke inlet of the wet deacidification tower The exothermic medium pipeline through the flow medium heat exchanger is communicated with the smoke outlet of the SCR denitrification and dust removal device; the smoke outlet of the wet deacidification tower is communicated with the smoke inlet of the chimney, which is the The smoke outlet communicates with the smoke inlet of the chimney through the heated medium pipeline of the flowing medium heat exchanger.

In the waste incineration flue gas purification method and system of the present invention, manganese-based and/or copper-based low-temperature catalysts are used during SCR denitrification treatment, so that the temperature of waste incineration flue gas required for SCR denitrification treatment is controlled at 150-250°C Then, set the entire flue gas purification process route as dry deacidification treatment → SCR denitrification treatment → wet deacidification treatment. The temperature of waste incineration flue gas before dry deacidification treatment is 180-230 ℃, the temperature of waste incineration flue gas after dry deacidification treatment is maintained at about 180-230 ℃, this temperature is just suitable for SCR denitrification treatment, and there is no special requirement for the temperature of waste incineration flue gas in subsequent wet deacidification treatment , the entire flue gas purification process is carried out in the process of stepwise decrease in the flue gas temperature. During the implementation of the entire flue gas purification process, there is no need for complex process steps such as heating the waste incineration flue gas. In addition, the waste incineration flue gas temperature of about 180-230°C after dry deacidification treatment is also very suitable for the adsorption of heavy metals and dioxins by activated carbon, and the process of using activated carbon to adsorb heavy metals and dioxins can be implemented while performing SCR denitrification treatment .

Compared with the prior art, the waste incineration flue gas purification method and system of the present invention have two beneficial effects: on the one hand, no additional heat treatment is required for the waste incineration flue gas, thereby avoiding waste of heat energy consumption, saving energy, and reducing On the other hand, since the entire flue gas purification process only has three processes: dry deacidification treatment, SCR denitrification treatment, and wet deacidification treatment, the process of using activated carbon to adsorb heavy metals and dioxins in SCR The process of denitrification treatment is carried out at the same time, thereby simplifying the process flow of the entire flue gas purification and reducing the investment in process equipment.

Description of drawings

Fig. 1 is the flowchart of the waste incineration flue gas purification method of the present invention;

Fig. 2 is a schematic composition diagram of the waste incineration flue gas purification system of the present invention.

In the figure: 1-dry deacidification tower, 11-dry powder supply device, 12-ammonia water supply device, 13-activated carbon powder supply device, 2-SCR denitrification and dust removal device, 21-fly ash storage bin, 3-fluid medium heat exchange Device, 4- wet deacidification tower, 41- deacidification agent supply device, 5- induced draft fan, 6- chimney.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing and specific embodiment:

This embodiment provides a method for purifying flue gas from garbage incineration. The method purifies the flue gas generated by incinerating garbage in a garbage incinerator, makes it harmless, and then discharges it into the atmosphere, thereby achieving the purpose of protecting the atmospheric environment. The flue gas produced by the waste incinerator burning waste is called waste incineration flue gas.

The waste incinerator involved in this embodiment has a waste heat recovery device, and the temperature of the waste incineration flue gas is about 180-230°C when it is finally discharged after being processed by the waste heat recovery device.

Referring to Fig. 1 , the flue gas purification method of this embodiment includes the following steps S1 to S4.

S1, perform dry deacidification treatment on the waste incineration flue gas, and maintain the temperature of the treated waste incineration flue gas at about 180-230°C.

The "dry deacidification treatment" is an existing deacidification process commonly used, and the solid deacidification powder it adopts is also called "dry powder" in the art, and the most commonly used deacidification powder in actual production is Sodium bicarbonate (NaHCO ₃ ) powder, slaked lime (Ca(OH) ₂ ) powder.

Since the dry deacidification treatment has little effect on the flue gas temperature, the temperature of the waste incineration flue gas can still be maintained at about 180-230°C after dry deacidification treatment.

S2, performing SCR denitrification treatment on the waste incineration flue gas after the dry deacidification treatment.

In the flue gas purification method of this embodiment, in addition to the traditional vanadium-titanium (V-Ti)-based and vanadium-tungsten-titanium (V-W-Ti)-based catalysts, manganese ( Mn)-based and/or copper (Cu)-based low-temperature catalysts, and a small amount of cerium (Ce), zirconium (Zr) and other elements are added to the catalyst to enhance the dispersion of Mn and Cu active components in the catalyst , the low-temperature denitrification activity of the catalyst was significantly improved.

The manganese-based low-temperature catalyst includes MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ , MnO, etc., among which MnO ₂ and Mn ₂ O ₃ are the main ones. The activity per unit area of MnO ₂ and the selectivity of Mn ₂ O ₃ can reach 90% of NOx removal efficiency at 180℃.

The copper-based low-temperature catalyst includes CuO, Cu ₂ O, etc., and the NOx removal efficiency can reach 80% in the temperature range of 180-230°C.

In this embodiment, the SCR denitrification treatment uses a low-temperature catalyst. In this way, as long as the waste incineration flue gas is kept within the temperature range of 150-250°C, a good denitrification reaction can be achieved, usually 80% of the denitrification efficiency can be achieved. , and the temperature of waste incineration flue gas after dry deacidification treatment is about 180-230°C, just in the temperature range of 150-250°C, so there is no need for additional heating or cooling treatment of waste incineration flue gas.

In addition, in the temperature range of 150-250 ° C, it is beneficial for the adsorption of heavy metals and dioxins by activated carbon. Therefore, in the process of SCR denitration treatment of waste incineration flue gas, activated carbon is also sprayed into waste incineration flue gas Powder to absorb heavy metals and dioxins in waste incineration flue gas. In this way, there is no need to set up a special device for "activated carbon adsorption of heavy metals and dioxins". At the same time, vanadium-titanium-based and vanadium-tungsten-titanium-based catalysts can promote the reaction between dioxins and oxygen, and dioxins are easily decomposed into non-toxic substances such as CO ₂ , H ₂ O, and HCl. Decomposition, so as to truly realize the out-of-stock treatment and dioxin removal.

S3, performing wet deacidification treatment on the waste incineration flue gas, so as to further remove residual acid gas in the waste incineration flue gas, and further remove dust particles in the waste incineration flue gas. The deacidification agent used in the wet deacidification treatment is alkaline sodium hydroxide (NaOH) solution.

In this process, a heat exchanger is used to exchange heat between "waste incineration flue gas before wet deacidification treatment" and "waste incineration flue gas after wet deacidification treatment", so that the waste before wet deacidification treatment The temperature of the incineration flue gas is lowered, and the temperature of the waste incineration flue gas after the wet deacidification treatment is raised to 100-150°C, so as to prevent the occurrence of white smoke when the flue gas is subsequently discharged. The "white smoke situation" mentioned here refers to the phenomenon that the water vapor in the flue gas discharged from the chimney cannot be quickly absorbed by the atmosphere, resulting in condensation of water vapor, resulting in visual pollution of white smoke.

The heat exchanger described here refers to a flow medium heat exchanger, which is a device in the prior art. Specifically, there are two medium flow pipelines in the heat exchanger, and the medium flowing in these two pipelines can The heat is transferred to each other across the tube wall, so that the lower temperature medium is heated and the temperature is raised, while the higher temperature medium is cooled and the temperature is lowered. In this embodiment, the heat exchanger used is a heat exchanger called "GGH heat exchanger", which is also an existing heat exchanger, where GGH is the abbreviation of "Gas Gas Heater" in English , the Chinese translation is "flue gas-flue gas heat exchanger".

S4. Finally, discharge the waste incineration flue gas that has been purified into the atmosphere.

The steps S1 to S4 included in the flue gas purification method of this embodiment are now completed.

In the flue gas purification method of this embodiment, manganese (Mn)-based and/or copper (Cu)-based low-temperature catalysts are used during SCR denitrification treatment, so that the temperature of waste incineration flue gas required for SCR denitrification treatment is controlled at In the temperature range of 150-250°C, then, set the entire flue gas purification process route as "dry deacidification treatment → SCR denitrification treatment → wet deacidification treatment", the waste incineration smoke before dry deacidification treatment The gas temperature is about 180-230°C, and the temperature of the waste incineration flue gas after the dry deacidification treatment is maintained at about 180-230°C. There is no special requirement on the gas temperature. The entire flue gas purification process is carried out in the process of decreasing the flue gas temperature step by step. In this way, in the implementation process of the entire flue gas purification method, there is no need to carry out waste incineration flue gas. Complex process steps such as heat treatment. It can be seen that the flue gas purification method of this embodiment has two advantages. On the one hand, there is no need to perform additional heat treatment on the waste incineration flue gas, thereby avoiding waste of heat energy consumption, saving energy, and reducing production costs. On the other hand, since the entire flue gas purification process only has three processes of "dry deacidification treatment, SCR denitrification treatment, and wet deacidification treatment", the entire flue gas purification process is simplified. Reduced investment in process equipment. In addition, the waste incineration flue gas temperature of about 180-230°C after dry deacidification treatment is also very suitable for the adsorption of heavy metals and dioxins by activated carbon, and it is possible to implement "adsorption of heavy metals and dioxins by activated carbon" while performing SCR denitrification treatment process, which further simplifies the process flow of flue gas purification.

This embodiment also provides a waste incineration flue gas purification system, which is used to implement the above flue gas purification method.

Referring to FIG. 2 , the flue gas purification system of this embodiment includes a dry deacidification tower 1 , an SCR denitrification and dust removal device 2 , a wet deacidification tower 4 , a flow medium heat exchanger 3 , an induced draft fan 5 and a chimney 6 .

The smoke inlet of the dry deacidification tower 1 communicates with the smoke outlet of the garbage incinerator (not shown in the figure) through the flue gas pipeline, and the garbage incineration flue gas discharged from the garbage incinerator first enters the dry The dry deacidification treatment is carried out in the deacidification tower 1, and the temperature of the treated waste incineration flue gas is maintained at about 180-230° C., and it leaves through the smoke outlet of the dry deacidification tower 1.

A dry powder supply device 11 is arranged above the dry deacidification tower 1, and the function of the dry powder supply device 11 is to provide a deacidification powder (i.e. "dry powder") for the dry deacidification treatment, where the deacidification powder can be carbonic acid Sodium hydrogen (NaHCO ₃ ) powder or slaked lime (Ca(OH) ₂ ) powder.

It should be noted that the dry powder supply device 11 is a conventional configuration of the dry deacidification tower 1 in the prior art.

The smoke inlet of the SCR denitration and dust removal device 2 communicates with the smoke outlet of the dry deacidification tower 1 through the flue gas pipeline, and the waste incineration flue gas processed by the dry deacidification tower 1 enters the SCR denitrification and dust removal device 2 The SCR denitrification treatment is carried out in the middle, and the treated waste incineration flue gas leaves the smoke outlet of the SCR denitrification and dust removal device 2.

Inside the SCR denitrification and dust removal device 2, there is a catalyst-coated filter component. Different from the traditional filter component, the catalyst coated on the filter component is not only the traditional vanadium-titanium (V-Ti) base, vanadium-tungsten-titanium ( In addition to V-W-Ti)-based catalysts, there are also manganese (Mn)-based and/or copper (Cu)-based low-temperature catalysts, that is, the catalysts used in the SCR denitrification and dust removal device 2 include manganese (Mn)-based and/or copper-based (Cu)-based low-temperature catalyst, in this way, as long as the waste incineration flue gas is kept in the temperature range of 150-250 °C, a good denitrification reaction can be achieved, usually with a denitrification efficiency of 80%. After the waste incineration flue gas is treated by the dry deacidification tower 1, its temperature is about 180-230°C, just in the temperature range of 150-250°C, so there is no need for additional heating or cooling of the waste incineration flue gas deal with.

The catalyst-coated filter component can be a catalyst ceramic fiber tube or a catalyst filter bag. The catalyst ceramic fiber tube and the catalytic filter bag have the same size, and can be used interchangeably in the SCR denitrification and dust removal device 2. Among the catalytic ceramic fiber tube and the catalytic filter bag, the most economical equipment can be selected according to changes in market costs, thereby expanding the purification capacity. Application scenarios of flue gas technology.

Ammonia water supply device 12 and activated carbon powder supply device 13 are arranged on the pipeline connected by the smoke inlet of SCR denitrification and dust removal device 2, and the ammonia gas in the ammonia water provided by said ammonia water supply device 12 is used as the denitrification required for SCR denitrification treatment. The activated carbon powder provided by the activated carbon powder supply device 13 is used for "using the activated carbon powder to absorb heavy metals and dioxins in the waste incineration flue gas while performing SCR denitrification treatment on the waste incineration flue gas".

A fly ash storage bin 21 is arranged below the SCR denitrification and dust removal device 2, and the function of the fly ash storage bin 21 is to store salt particles, flue gas dust and unreacted deacidification powder generated during the SCR denitrification process.

It should be noted that the ammonia water supply device 12 , the fly ash storage bin 21 and the catalyst-coated filter components are conventional configurations of the SCR denitrification and dust removal device 2 in the prior art.

The flow medium heat exchanger 3 is a device in the prior art, which has two medium flow pipelines, wherein one medium flow pipeline is called heat release medium pipeline, and the other medium flow pipeline is called In the heating medium pipeline, the "temperature of the medium flowing in the heat releasing medium pipeline" is higher than the "temperature of the medium flowing in the heating medium pipeline", and the medium in the heat releasing medium pipeline can transfer heat through the pipe wall The medium for the heating medium pipeline. The flow medium heat exchanger 3 used in this embodiment is a heat exchanger called "GGH heat exchanger", which is also a conventional heat exchanger.

The smoke inlet of the wet deacidification tower 4 communicates with the smoke outlet of the SCR denitrification and dust removal device 2 through the flue gas pipeline and the heat release medium pipeline of the flow medium heat exchanger 3, and the wet deacidification tower 4 The smoke outlet of the chimney is communicated with the smoke inlet of the chimney 6 through the flue gas pipeline and the heated medium pipeline of the flow medium heat exchanger 3 , and the induced draft fan 5 is arranged on the flue gas pipeline connected with the smoke inlet of the chimney 6 .

The waste incineration flue gas processed by the SCR denitrification and dust removal device 2 enters the wet deacidification tower 4 for wet deacidification treatment, and the treated waste incineration flue gas exits from the flue outlet of the wet deacidification tower 4 . During this process, the flow medium heat exchanger 3 performs heat exchange between "the waste incineration flue gas before entering the wet deacidification tower 4" and "the waste incineration flue gas after leaving the wet deacidification tower 4", so that the waste incineration flue gas entering the wet deacidification tower 4 The temperature of the waste incineration flue gas before the wet deacidification tower 4 is lowered, and the temperature of the waste incineration flue gas after leaving the wet deacidification tower 4 is raised to 100-150°C, thereby preventing the smoke from occurring when the subsequent chimney 6 discharges flue gas. The condition of white smoke.

The wet deacidification tower 4 is provided with a deacidification agent supply device 41, and the deacidification agent supply device 41 is used to provide a deacidification agent for wet deacidification treatment. The deacidification agent here uses alkaline sodium hydroxide (NaOH) solution, and the flue gas enters the wet deacidification tower and further contacts with the sodium hydroxide solution in countercurrent, so that the flue gas and the sodium hydroxide solution can fully react, and at the same time pass through The circulation pump circulates the solution at the bottom of the wet deacidification tower.

It should be noted that the deacidification agent supply device 41 is a conventional configuration of the wet deacidification tower 4 in the prior art.

Finally, the waste incineration flue gas that has been purified is discharged into the atmosphere through the chimney 6 under the action of the induced draft of the induced draft fan 5 .

The flue gas purification system of this embodiment can realize the above-mentioned waste incineration flue gas purification method, thereby realizing the two advantages of the flue gas purification method, that is, on the one hand, it avoids waste of heat energy consumption, saves energy, and reduces Production cost, on the other hand, also simplifies the process flow of the whole flue gas purification, thereby reducing the investment in process equipment.

The above are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in this within the scope of protection of the invention.

Claims (10)

1. A method for purifying waste incineration flue gas, characterized in that: the method for purifying flue gas comprises: S1, dry deacidification of waste incineration flue gas; S2, performing SCR denitration treatment on the waste incineration flue gas, the catalyst used in the SCR denitration treatment includes a low-temperature catalyst; S3, performing wet deacidification treatment on waste incineration flue gas; S4, discharging waste incineration flue gas into the atmosphere. 2. The method for purifying waste incineration flue gas according to claim 1, characterized in that: the low-temperature catalyst is a manganese-based catalyst and/or a copper-based catalyst. 3. The method for purifying waste incineration flue gas according to claim 2, characterized in that cerium and/or zirconium are added to the low-temperature catalyst. 4. The method for purifying waste incineration flue gas according to claim 1, characterized in that: said S2 further comprises: spraying activated carbon powder into the waste incineration flue gas during the SCR denitrification process. 5. The method for purifying waste incineration flue gas according to claim 1, characterized in that: said S3 further comprises: during the wet deacidification process, using a heat exchanger to remove the waste incineration fume before wet deacidification The heat exchange is performed between the waste gas and the waste incineration flue gas after wet deacidification treatment. 6. A waste incineration flue gas purification system, characterized in that it includes a dry deacidification tower (1), an SCR denitrification and dust removal device (2), a wet deacidification tower (4), an induced draft fan (5) and a chimney ( 6); The smoke inlet of the dry deacidification tower (1) is connected with the smoke exhaust port of the garbage incinerator; The smoke inlet of the SCR denitration and dust removal device (2) is connected to the smoke outlet of the dry deacidification tower (1), and the catalyst used in the SCR denitration and dust removal device (2) includes a low-temperature catalyst; The smoke inlet of the wet deacidification tower (4) is connected with the smoke outlet of the SCR denitrification and dust removal device (2), and the smoke outlet of the wet deacidification tower (4) is connected with the smoke inlet of the chimney (6) , the induced draft fan (5) is arranged at the smoke inlet of the chimney (6). 7. The garbage incineration flue gas purification system according to claim 6, characterized in that: the low-temperature catalyst is a manganese-based catalyst and/or a copper-based catalyst. 8. The waste incineration flue gas purification system according to claim 7, characterized in that cerium and/or zirconium are added to the low-temperature catalyst. 9. The waste incineration flue gas purification system according to claim 6, characterized in that: an activated carbon powder supply device (13) is provided on the pipeline connected to the smoke inlet of the SCR denitrification and dust removal device (2). 10. The waste incineration flue gas purification system according to claim 6, characterized in that: the flue gas purification system further comprises a flow medium heat exchanger (3); The smoke inlet of the wet deacidification tower (4) is connected with the smoke outlet of the SCR denitrification and dust removal device (2), so that the smoke inlet of the wet deacidification tower (4) passes through the flow medium heat exchanger (3 ) The exothermic medium pipeline is connected with the smoke outlet of the SCR denitrification and dust removal device (2); The smoke outlet of the wet deacidification tower (4) is connected with the smoke inlet of the chimney (6), so that the smoke outlet of the wet deacidification tower (4) is heated by the flow medium heat exchanger (3) The medium pipeline communicates with the smoke inlet of the chimney (6).

Images