Household garbage incineration fly ash pyrolysis flue gas purification system

Abstract

The utility model relates to a flue gas purification system for household garbage incineration fly ash pyrolysis. The flue gas purification system comprises a bag-type dust collector I, a flue gas heater I, a deacidification tower I, an activated carbon adsorption device, a bag-type dust collector II, a denitration reactor, a deacidification tower II, an induced draft fan and a chimney which are sequentially connected along a flue gas flow path, the purification system further comprises a first flue gas heat exchanger, a second flue gas heater and a second flue gas heat exchanger, flue gas subjected to dust removal through the second bag-type dust remover enters the first flue gas heat exchanger and the second flue gas heater to be heated, and the heated flue gas enters the denitration reactor to be subjected to denitration reaction. The flue gas after denitration reaction is returned to the flue gas heat exchanger I to be subjected to heat exchange and cooling with the flue gas before temperature rise, then the flue gas enters a flue gas heat exchanger II to be cooled again, the cooled flue gas enters a deacidification tower II to be subjected to deacidification reaction, and the flue gas after deacidification reaction is returned to the flue gas heat exchanger II to be subjected to heat exchange and temperature rise; and the flue gas subjected to heat exchange and temperature rise enters a chimney through an induced draft fan and then is discharged. According to the device, various pollutants in the incineration fly ash pyrolysis flue gas can be effectively removed, and the flue gas can be discharged after reaching the standard.

Description

Technical Field

[0001] The utility model belongs to the technical field of harmless resource utilization of domestic waste incineration fly ash, and particularly relates to a pyrolysis flue gas purification system for domestic waste incineration fly ash. Background Art

[0002] Domestic waste incineration fly ash, hereinafter referred to as "fly ash", is derived from fly ash collected from the flue gas of waste incineration power plants, including fluidized bed fly ash and grate furnace fly ash. The main components in fly ash are CaO, SiO2, Na2O, K2O, Fe2O3, Al2O3, and MgO, among which the mass fraction of CaO is the highest, being 20.4 - 37.9%. The main harmful substances are heavy metals (such as Zn, Pb, Cu, Cr, Cd, Ni, and Hg, etc.) and dioxin-like organic compounds. The mass fraction of chlorine in incineration fly ash is the highest, which can exceed 25% at most, and the proportion of soluble chlorine in the total chlorine is 40.6 - 83.9%. Among them, it contains carcinogenic dioxin-like organic substances and trace inorganic heavy metal substances, and is listed as "HW18" hazardous waste.

[0003] Currently, the main treatment methods for the harmless resource utilization of domestic waste incineration fly ash are co-processing in cement kilns, high-temperature melting, high-temperature sintered ceramsite, low-temperature pyrolysis, etc. After the fly ash is treated by high-temperature technology, the flue gas contains a large amount of acidic gases, volatile heavy metal gases, dioxins and other harmful gases. If not treated, it will not only cause serious pollution to the ecological environment, but also pose a serious threat to human health. Content of the Utility Model

[0004] Based on the above-mentioned drawbacks and deficiencies existing in the prior art, one of the purposes of the present utility model is to at least solve one or more of the above problems existing in the prior art. In other words, one of the purposes of the present utility model is to provide a pyrolysis flue gas purification system for domestic waste incineration fly ash that meets one or more of the foregoing requirements.

[0005] In order to achieve the above object of the utility model, the present utility model provides the following solution:

[0006] A pyrolysis flue gas purification system for domestic waste incineration fly ash, comprising a bag filter I, a flue gas heater I, a deacidification tower I, an activated carbon adsorption device, a bag filter II, a denitration reactor, a deacidification tower II, an induced draft fan and a chimney, which are sequentially connected along the flue gas flow path;

[0007] The purification system further includes a first flue gas heat exchanger, a second flue gas heater, and a second flue gas heat exchanger. The flue gas after being dust-removed by the second bag filter enters the first flue gas heat exchanger and the second flue gas heater for temperature rise. The flue gas after temperature rise enters the denitration reactor for denitration reaction. The flue gas after denitration reaction returns to the first flue gas heat exchanger to exchange heat with the flue gas before temperature rise for temperature reduction, and then enters the second flue gas heat exchanger for further temperature reduction. The flue gas after temperature reduction enters the second acid removal tower for acid removal reaction. The flue gas after acid removal reaction returns to the second flue gas heat exchanger for heat exchange and temperature rise, and the flue gas after heat exchange and temperature rise is discharged into the chimney through the induced draft fan.

[0008] As a preferred solution, the inlet of the first bag filter is connected to the smoke exhaust port of the pyrolysis furnace.

[0009] As a preferred solution, the first acid removal tower is equipped with a first acid removal reagent bin.

[0010] As a preferred solution, the activated carbon adsorption device adopts an activated carbon injection adsorption system.

[0011] As a preferred solution, the denitration reactor is equipped with a denitration reducing agent generating device.

[0012] As a preferred solution, the denitration reactor is an SCR denitration reactor.

[0013] As a preferred solution, the dust emission concentration at the outlets of the first bag filter and the second bag filter ≤ 10mg / Nm 3 .

[0014] As a preferred solution, the heating methods of the first flue gas heater and the flue gas heater are burner or electric heater.

[0015] As a preferred solution, the second acid removal tower is equipped with a second acid removal reagent bin.

[0016] As a preferred solution, the ash hopper of the second bag filter adopts electric heat tracing.

[0017] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0018] (1) The present utility model adopts two-stage flue gas heaters, realizing the removal of different pollutants at different temperatures, and the process design has strong reliability;

[0019] (2) The present utility model adopts two-stage flue gas heat exchangers, realizing the recovery and utilization of heat energy and saving energy;

[0020] (3) The present utility model adopts two-stage bag filters to remove particulate matters, and the emission concentration of particulate matters ≤ 10mg / Nm 3 , and the particulate matter removal rate reaches 99.95%, and the process design has strong reliability;

[0021] (4) The present utility model adopts two-stage deacidification, and the deacidification efficiency is ≥ 95%;

[0022] (5) The present utility model adopts SCR denitration, and the catalyst efficiency is ≥ 98%;

[0023] (6) The present utility model can meet the operation of the purification system under 20% - 110% load, and the system has a large operable space;

[0024] (7) The present utility model can make the pyrolysis tail gas meet the emission standards. Description of the Drawings

[0025] Figure 1 It is a structural diagram of the pyrolysis flue gas purification system for municipal solid waste incineration fly ash in Embodiment 1 of the present utility model. Detailed Embodiment

[0026] In order to more clearly illustrate the embodiments of the present utility model, the specific embodiments of the present utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other embodiments can be obtained.

[0027] Embodiment 1:

[0028] As Figure 1 shown, the pyrolysis flue gas purification system for municipal solid waste incineration fly ash in this embodiment includes a pyrolysis furnace 1, a bag filter 2, a flue gas heater 3, a deacidification tower 4, an activated carbon adsorption device 5, a bag filter 6, a flue gas heat exchanger 7, a flue gas heater 8, a denitration reactor 9, a flue gas heat exchanger 10, a deacidification tower 11, an induced draft fan 12, and a chimney 13.

[0029] The deacidification tower 4 in this embodiment adopts a first deacidification agent for primary deacidification. The first deacidification agent can be sodium bicarbonate, calcium hydroxide, sodium hydroxide, ammonia water, etc.; specifically, the deacidification tower 4 is equipped with a deacidification agent bin 14 and an automatic feeding device. The deacidification agent bin 14 is used to store the first deacidification agent, and the automatic feeding of the first deacidification agent is realized through the automatic feeding device.

[0030] The activated carbon adsorption device 5 in this embodiment adopts an activated carbon injection adsorption system to remove dioxins and heavy metals. The specific structure of the activated carbon injection adsorption system can refer to the prior art and will not be elaborated here.

[0031] The specification requirements of the bag filter 2 and the bag filter 6 in this embodiment are that the dust emission concentration at the outlet of the dust collector is ≤ 10 mg / Nm 3Among them, the flue gas, activated carbon powder, deacidification agent I, and treatment products enter the bag filter 6 together, forming a filter cake on the surface of the filter bags of the dust collector, which can further remove pollutants. To prevent the filter bags from caking, the ash hopper is electrically heated.

[0032] In this embodiment, the flue gas after being dust-removed by the bag filter 6 enters the flue gas heat exchanger 7 and the flue gas heater 8 for temperature increase. The heated flue gas enters the denitration reactor 9 for denitration reaction. The flue gas after the denitration reaction returns to the flue gas heat exchanger 7 to exchange heat with the flue gas before temperature increase (i.e., the flue gas after being dust-removed by the bag filter 6) for temperature reduction, and then enters the flue gas heat exchanger 10 for further temperature reduction. The cooled flue gas enters the deacidification tower 11 for deacidification reaction. The flue gas after the deacidification reaction returns to the flue gas heat exchanger 10 for heat exchange and temperature increase. The flue gas after heat exchange and temperature increase enters the chimney 13 through the induced draft fan 12 and is discharged.

[0033] In this embodiment, the denitration reactor 9 is an SCR denitration reactor, and the denitration reactor is equipped with a denitration reductant generation device 15. The denitration reductant can be urea, methanol, or ammonia water.

[0034] In this embodiment, the flue gas heater 3 and the flue gas heater 8 are composed of a set of burners or electric heaters and their auxiliary systems.

[0035] In this embodiment, the inlet and outlet flue ducts of the denitration reactor 9 adopt flue gas heat exchange to recover part of the heat to heat the flue gas temperature at the inlet of the denitration reactor, and at the same time reduce the emission temperature to protect the low-temperature equipment in the subsequent sections.

[0036] In this embodiment, the deacidification tower 11 uses deacidification agent II for deacidification and particulate removal. The deacidification tower II is equipped with a deacidification agent bin II 16 for storing deacidification agent II. The deacidification agent II can be sodium bicarbonate, calcium hydroxide, sodium hydroxide, or ammonia water.

[0037] In this embodiment, the inlet and outlet of the deacidification tower 11 are configured with flue gas to reduce the temperature of the flue gas entering the deacidification tower to protect the tower internals from high-temperature impact, and at the same time increase the flue gas discharge temperature to reduce "white smoke".

[0038] The purification process of the domestic waste incineration fly ash pyrolysis flue gas purification system in this embodiment is as follows:

[0039] S1. The flue gas generated by the pyrolysis furnace 1 flows through the bag filter 2 and the flue gas heater 3 for primary dust removal and primary temperature increase;

[0040] S2. The heated flue gas undergoes a chemical reaction with deacidification agent I in the deacidification tower 4, and after leaving the deacidification tower 4, it undergoes an adsorption reaction with the activated carbon sprayed by the activated carbon adsorption device 5;

[0041] S3. After the adsorption reaction, the flue gas flows through the bag filter 6 for secondary dust removal;

[0042] S4. After dust removal, the flue gas enters the flue gas heat exchanger 7 and the flue gas heater 8 for reheating;

[0043] S5. The reheated flue gas is mixed with the denitrification reducing agent and then enters the denitrification reactor 9 for denitrification reaction;

[0044] S6. The flue gas after denitrification reaction returns to the flue gas heat exchanger 7 to be cooled with the flue gas before reheating and then enters the flue gas heat exchanger 10 for further cooling;

[0045] S7. The cooled flue gas enters the acid removal tower 11 to react with the second acid removal agent for acid removal;

[0046] S8. The flue gas after acid removal reaction returns to the flue gas heat exchanger 10 for reheating again, and finally is discharged into the chimney 13 through the induced draft fan 12.

[0047] Example 2:

[0048] The municipal solid waste incineration fly ash pyrolysis flue gas purification system of this example is different from that of Example 1 in that:

[0049] The activated carbon adsorption device uses a conventional activated carbon adsorption device to replace the activated carbon injection adsorption system in Example 1, and can also remove dioxins and heavy metals;

[0050] Other structures are the same as those in Example 1.

[0051] Example 3:

[0052] The municipal solid waste incineration fly ash pyrolysis flue gas purification system of this example is different from that of Example 1 in that:

[0053] The two flue gas heaters can be configured with various independent burners or electric heaters and their ancillary systems;

[0054] Other structures are the same as those in Example 1.

[0055] Example 4:

[0056] The municipal solid waste incineration fly ash pyrolysis flue gas purification system of this example is different from that of Example 1 in that:

[0057] The denitrification reactor can also use a denitrification reactor of other existing denitrification processes;

[0058] Other structures are the same as those in Example 1.

[0059] Example 5:

[0060] The municipal solid waste incineration fly ash pyrolysis flue gas purification system of this example is different from that of Example 1 in that:

[0061] The acid removal tower can be manually fed without an additional acid removal agent bin;

[0062] Other structures are the same as those in Embodiment 1.

[0063] The above description only details the preferred embodiments and principles of the present utility model. For those of ordinary skill in the art, according to the idea provided by the present utility model, there will be changes in the specific implementation manners, and these changes should also be regarded as the protection scope of the present utility model.

Claims

1. A pyrolysis flue gas purification system for municipal solid waste incineration fly ash, characterized in that It includes a first bag filter, a first flue gas heater, a first deacidification tower, an activated carbon adsorption device, a second bag filter, a denitration reactor, a second deacidification tower, an induced draft fan and a chimney, which are connected in sequence along the flue gas flow path; The purification system further includes a first flue gas heat exchanger, a second flue gas heater and a second flue gas heat exchanger. The flue gas after being dust-removed by the second bag filter enters the first flue gas heat exchanger and the second flue gas heater to be heated up. The heated flue gas enters the denitration reactor for denitration reaction. The flue gas after the denitration reaction returns to the first flue gas heat exchanger to exchange heat with the flue gas before heating up and is cooled down, then enters the second flue gas heat exchanger to be cooled down again. The cooled flue gas enters the second deacidification tower for deacidification reaction. The flue gas after the deacidification reaction returns to the second flue gas heat exchanger to exchange heat and be heated up. The flue gas heated up by heat exchange is discharged into the chimney through the induced draft fan.

2. The municipal solid waste incineration fly ash pyrolysis flue gas purification system according to claim 1, wherein The inlet of the first bag filter is connected to the smoke exhaust port of the pyrolysis furnace.

3. The municipal solid waste incineration fly ash pyrolysis flue gas purification system according to claim 1, wherein, The first deacidification tower is equipped with a first deacidification reagent bin.

4. The municipal solid waste incineration fly ash pyrolysis flue gas purification system according to claim 1, characterized in that, The activated carbon adsorption device adopts an activated carbon injection adsorption system.

5. The domestic waste incineration fly ash pyrolysis flue gas purification system according to claim 1, characterized in that, The denitration reactor is equipped with a denitration reductant generation device.

6. The municipal solid waste incineration fly ash pyrolysis flue gas purification system according to claim 1, wherein, The denitration reactor is an SCR denitration reactor.

7. The pyrolysis flue gas purification system for municipal solid waste incineration fly ash according to claim 1, wherein, The outlet flue dust emission concentration of the bag filter 1 and the bag filter 2 ≤ 10 mg / Nm 3 .

8. The flue gas purification system for pyrolysis of municipal solid waste incineration fly ash according to claim 1, wherein The heating methods of the first flue gas heater and the second flue gas heater are burners or electric heaters.

9. The municipal solid waste incineration fly ash pyrolysis flue gas purification system according to claim 1, wherein The second deacidification tower is equipped with a second deacidification reagent bin.

10. The municipal solid waste incineration fly ash pyrolysis flue gas purification system according to claim 1, wherein, The ash hopper of the second bag filter adopts electric heat tracing.

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