阅读说明：本技术 一种危废焚烧系统及其运行工艺 (Hazardous waste incineration system and operation process thereof ) 是由 沈宏伟 徐丽婷 王天娇 郭无双 侯霞丽 钱琨 吴穹 王丽霞 于 2021-08-23 设计创作，主要内容包括：本发明公开了一种危废焚烧系统及其运行工艺,该系统包括通过烟道依次连接的危废焚烧炉、一级余热锅炉、高温除尘器、二级余热锅炉、中高温除尘-脱硝脱二噁英装置、省煤器、GGH烟气换热器、引风机、烟囱；其中,干法脱酸系统通过烟道设置于所述二级余热锅炉和所述中高温除尘-脱硝脱二噁英装置之间；所述GGH烟气换热器另设烟道连接至湿法脱酸系统,所述湿法脱酸系统通过烟道回连至所述GGH烟气换热器。本发明的危废焚烧系统对危废的适应性强,有效解决二噁英的再生成问题,同时提高系统的能量利用率,缩短工艺链长度,实现危废的烟气超低排放。(The invention discloses a hazardous waste incineration system and an operation process thereof, wherein the system comprises a hazardous waste incinerator, a primary waste heat boiler, a high-temperature dust remover, a secondary waste heat boiler, a medium-high temperature dust removal-denitration and dioxin removal device, an economizer, a GGH flue gas heat exchanger, an induced draft fan and a chimney which are sequentially connected through a flue; the dry deacidification system is arranged between the secondary waste heat boiler and the medium-high temperature dedusting-denitration-dioxin removal device through a flue; the GGH flue gas heat exchanger is additionally provided with a flue connected to a wet deacidification system, and the wet deacidification system is connected to the GGH flue gas heat exchanger through the flue. The hazardous waste incineration system disclosed by the invention has strong adaptability to hazardous waste, effectively solves the problem of regeneration of dioxin, improves the energy utilization rate of the system, shortens the length of a process chain, and realizes ultralow emission of flue gas of the hazardous waste.)

1. A hazardous waste incineration system is characterized by comprising a hazardous waste incinerator, a primary waste heat boiler, a high-temperature dust remover, a secondary waste heat boiler, a dry deacidification system, a medium-high temperature dust removal-denitration and dioxin removal device, an economizer, a GGH flue gas heat exchanger, a wet deacidification system, an induced draft fan and a chimney;

the hazardous waste incinerator is sequentially connected with the primary waste heat boiler, the high-temperature dust remover, the secondary waste heat boiler, the medium-high temperature dust removal-denitration and dioxin removal device, the economizer and the GGH flue gas heat exchanger through a flue;

the dry deacidification system is arranged between the secondary waste heat boiler and the medium-high temperature dedusting-denitration and dioxin removal device through a flue;

the GGH flue gas heat exchanger comprises a flue gas inlet, a hot flue gas port, a cold flue gas port and a flue gas outlet, the coal economizer is connected to the flue gas inlet of the GGH flue gas heat exchanger through a flue, the hot flue gas port of the GGH flue gas heat exchanger is connected to the wet deacidification system through the flue, the wet deacidification system is connected back to the cold flue gas port of the GGH flue gas heat exchanger through the flue, and the flue gas outlet of the GGH flue gas heat exchanger is connected with the induced draft fan through the flue;

the induced draft fan is connected to the chimney through the flue.

2. The hazardous waste incineration system of claim 1, further comprising an incineration fly ash disposal system, wherein the hazardous waste incinerator, the primary waste heat boiler and the high temperature dust collector are respectively provided with a flue connected to the incineration fly ash disposal system.

3. The hazardous waste incineration system of claim 1, further comprising an ammonia injection system disposed between the primary exhaust-heat boiler and the high temperature dust collector; or between the high-temperature dust remover and the secondary waste heat boiler; or the device is arranged between the secondary waste heat boiler and the medium-high temperature dust removal-denitration and dioxin removal device.

4. The hazardous waste incineration system according to claim 1, further comprising a deacidification ash circulation system and a deacidification ash resource utilization system, both of which are connected to the medium-high temperature dust removal-denitration and dioxin removal device, wherein the deacidification ash circulation system is connected back to a position between the secondary waste heat boiler and the medium-high temperature dust removal-denitration and dioxin removal device through a flue.

5. The hazardous waste incineration system of claim 1, further comprising a waste heat utilization device, wherein the economizer is further provided with a flue which is sequentially connected with the secondary waste heat boiler and the primary waste heat boiler and is finally connected to the waste heat utilization device.

6. The hazardous waste incineration system of any one of claims 1-5, wherein the high temperature dust collector is a high temperature ceramic dust collector or a high temperature metal dust collector.

7. The hazardous waste incineration system according to any one of claims 1 to 5, wherein the medium-high temperature dust removal-denitration-dioxin removal device is an integrated device or a split design of a medium-high temperature dust removal device + SCR denitration-dioxin removal device; the filter element of the medium-high temperature dust removal-denitration and dioxin removal device is made of ceramic or metal.

8. The operation process of the hazardous waste incineration system of any one of claims 1-5, comprising the steps of:

step 1) after entering a hazardous waste incineration system, hazardous waste firstly enters a hazardous waste incinerator for incineration, the hazardous waste incinerator also comprises a secondary combustion chamber, the incineration temperature is higher than 1100 ℃, the smoke retention time is 2s, and therefore the yield of dioxin is reduced;

recovering heat of the high-temperature flue gas after incineration in the step 2) through a primary waste heat boiler, cooling to about 550 ℃, entering a high-temperature dust remover, and intercepting and removing most of dust in the flue gas;

step 3), enabling the dedusted flue gas to enter a secondary waste heat boiler, and recovering waste heat again, wherein the temperature of the flue gas is reduced to 250-300 ℃;

step 4) enabling the flue gas with the temperature of 250-300 ℃ to enter a medium-high temperature dedusting-denitration and dioxin-removing device, and spraying a deacidification agent through a dry deacidification system to react with the acid gas in the flue gas, so that the concentration of the acid gas is reduced, and the corrosion risk is reduced; the medium-high temperature dedusting-denitration and dioxin-removal device is also used as a deacidification reaction container;

the medium-high temperature dust removal-denitration and dioxin removal device is provided with a filter element, and a catalyst is covered on the filter element; dedusting by a filter element, collecting fly ash generated by a dry method, and ensuring that the dust reaches the standard; the catalyst simultaneously catalyzes and denitrates and removes dioxin, so that the dioxin is completely decomposed;

step 6) after passing through a medium-high temperature dust removal-denitration and dioxin removal device, the flue gas is subjected to denitration, dioxin removal, dust removal and partial deacidification, enters an economizer and is further recycled for residual energy, and the temperature of the flue gas is reduced to about 200 ℃;

step 7), allowing the flue gas at about 200 ℃ to pass through a GGH flue gas heat exchanger and then enter a wet deacidification system, removing the residual acid gas and refluxing to the GGH flue gas heat exchanger, wherein the GGH flue gas heat exchanger exchanges heat between the high-temperature flue gas before wet treatment and the low-temperature flue gas after wet treatment; in the high-temperature section, the temperature of the flue gas is reduced from 200 ℃ to about 100 ℃ and then the flue gas enters a wet deacidification system; in the low-temperature section, the flue gas at about 60 ℃ coming out of the wet deacidification system is heated to about 160 ℃; the flue gas before and after the wet method realizes non-contact heat exchange in the GGH flue gas heat exchanger;

and 8) finally, enabling the flue gas which flows back to the GGH flue gas heat exchanger through the wet deacidification system to enter an induced draft fan through a flue gas outlet, and discharging the clean flue gas into the atmosphere through a chimney through the induced draft fan after the clean flue gas reaches the standard.

9. The operation process of the hazardous waste incineration system according to claim 8, further comprising steps 9), 10), 11) and 12), specifically as follows:

step 9), taking ash generated by the hazardous waste incinerator, the primary waste heat boiler and the high-temperature dust remover as hazardous waste, and performing harmless treatment in an incineration fly ash disposal system;

step 10) spraying the reactant for SCR denitration into the flue gas by the ammonia spraying systemNH is generated after evaporation by utilizing the heat of high-temperature flue gas₃With NO in the presence of a catalyst_xReacting to produce harmless N₂(ii) a The injection point of the ammonia injection system can be selected between a first-stage waste heat boiler and a high-temperature dust remover, between the high-temperature dust remover and a second-stage waste heat boiler or between the second-stage waste heat boiler and a medium-high temperature dust removal-denitration and dioxin removal device;

step 11), circulating a part of the collected deacidification fly ash to the medium-high temperature dedusting-denitration and dioxin-removing device through a deacidification ash circulating system for further deacidification, so that the deacidification efficiency is improved, and the utilization rate of the deacidification agent is improved; the rest part is subjected to resource utilization through a deacidification ash resource utilization system;

and step 12) the primary waste heat boiler, the secondary waste heat boiler and the economizer recover the energy of the flue gas to a waste heat utilization device to realize waste heat utilization in a mode of heating steam by using the waste heat of the flue gas.

Technical Field

The invention belongs to the technical field of environmental protection, and particularly relates to a hazardous waste incineration system and an operation process thereof.

Background

Hazardous waste, also called hazardous waste, refers to solid waste with hazardous characteristics listed in the national hazardous waste list or identified according to the national hazardous waste identification standard and identification method. Hazardous waste contains a large amount of harmful substances, can cause huge damage to the surrounding environment, has great harm to human life, and therefore needs to be subjected to harmless treatment. The hazardous waste incineration is a technical scheme which is applied more at present, and can effectively realize harmlessness and reduction aiming at combustible hazardous waste. However, because the hazardous waste contains too many harmful components, the gas generated after high-temperature incineration contains high-concentration dioxin, dust and SO_x、HCl、NO_xEqual pollutionThe materials are discharged only after being treated by a flue gas purification system to reach the standard. Particularly, the content of dioxin and HCl is high, and dioxin is the most toxic substance known at present and is extremely harmful to human bodies; and the HCl with high concentration not only has high treatment difficulty, but also has strong corrosivity and extremely high requirements on the materials of the downstream equipment of the incinerator.

The hazardous waste incineration pollutants generally contain dust (fly ash) and NO_x、HCl、SO₂And harmful substances such as dioxin. Wherein, the dust generally adopts the sack cleaner, can effectively realize the dust removal purpose. The fly ash is collected under system equipment after incineration, and the main sources are dust in flue gas and ash generated by a flue gas purification process, such as deacidification ash and the like. Because the dust in the flue gas contains harmful substances such as heavy metals, most of the collected fly ash belongs to hazardous waste, and the treatment cost of the hazardous waste is very high. NO_xIs relatively low and SNCR denitrification can be used, but results in ammonia slip. The ammonia escaping at the rear end can react with HCl in the flue gas and the like at low temperature to generate aerosol, which not only causes pollution, but also leads to excessive dust. HCl and SO₂Due to the high initial concentration, it is generally necessary to couple various deacidification processes, such as dry process and wet process, to reach the emission standard. Dioxin is generally placed in a chamber that provides a flue gas residence time of > 1100 ℃ for 2s to reduce the original generation of dioxin. However, because a large amount of dioxin precursors are carried in flue gas, particularly dust, dioxin is generated in an interval of about 200-550 ℃, the existing hazardous waste incineration project generally adopts a water spray quench tower to rapidly cool the flue gas within 1s so as to avoid the area, and therefore the concentration of the dioxin is reduced. Even so, the concentration of dioxin in flue gas after quenching can still reach nearly 10ng-TEQ/Nm³And the rear end has the standard-reaching risk even if activated carbon adsorption is set. Meanwhile, because the quenching tower generally adopts water spray rapid evaporation quenching, on one hand, the waste heat energy of the flue gas at 200-550 ℃ is lost and cannot be utilized; on the other hand, along with the reduction of the temperature and the improvement of the water content, the corrosivity and the humidity of the flue gas after the quenching tower are greatly increased, and the problems of corrosion and blockage of equipment are more easily caused.

The patent and the application about the dangerous waste incineration system are more, and the current relatively mature mainstream process adopts: the technical combination of quenching, dry deacidification, activated carbon spraying, cloth bag and wet method is disclosed in patent No. CN 103611399B: according to the technology, incinerated flue gas is quenched by a double-fluid spray gun to avoid a dioxin regeneration interval, then dry deacidification is carried out, activated carbon adsorbs dioxin and heavy metals, cloth bag dust removal is carried out, and finally wet deacidification is carried out and then emission is carried out. The technology is applied more at present, but has the defects of incomplete dioxin reduction, high fly ash yield, low energy utilization rate, low deacidification efficiency, no denitration system, easy corrosion and easy blockage, low integral smoke emission standard and the like.

The publication number CN109185897B provides a set of gas purification and fly ash treatment system applied to high-chlorine dangerous waste incineration flue gas, wherein the flue gas purification adopts quenching, a catalytic cloth bag, dry deacidification, a cloth bag, water washing deacidification, alkali washing deacidification, wet electric precipitation and activated carbon layer adsorption. The technology mainly aims at the incineration of high-chlorine hazardous wastes, and therefore, multiple groups of process coupling are adopted in aspects of deacidification, dioxin removal and the like to improve the efficiency, the adaptability to hazardous waste raw materials is higher, and the purification efficiency is higher. However, the system is complex, and the problems of corrosion, blockage, low energy utilization rate and the like caused by rapid cooling are not solved.

The patent of publication No. CN211345334U adopts a waste heat boiler, an economizer, a semi-dry deacidification method, activated carbon injection, a dust remover, a heat exchanger, an SCR and a heat exchanger. The technology introduces devices such as a waste heat boiler, an economizer, a heat exchanger and the like, and recycles the waste heat of the flue gas generated by incineration; the coal economizer is used for realizing rapid cooling to reduce the generation of dioxin; deacidifying by adopting a semi-dry method technology; the rear end is connected with SCR for denitration to realize NO_xAnd (4) ultralow emission. But the technology has the problems of high quenching difficulty of the economizer, steam consumption and heating for low-temperature SCR, incomplete emission reduction of dioxin, low deacidification efficiency by a semidry method and the like.

In summary, the following problems mainly exist in the current system technology for hazardous waste incineration:

(1) adopt quench tower cooling to reduce the dioxin and generate, nevertheless if adopt the mode of water spray quench, can lose the waste heat of a large amount of flue gases, and arouse the corruption and the jam problem of rear end equipment. If adopt the economizer that CN211345334U mentioned, compare the high efficiency of direct evaporation heat transfer, the heat exchange efficiency of economizer is lower, and it is very big to cool down the flue gas fast in 1s, and the flue gas after the cooling is though the moisture content does not rise moreover, and corrosivity still is higher.

(2) The emission reduction of dioxin is not thorough, and the regeneration of the dioxin can be only reduced by the quenching tower, but the amount of the dioxin is still high after the dioxin is quenched. And the standard of dangerous waste is too low at present, and the requirement of carrying the standard exists. If the current national standard discharge standard of dangerous waste dioxin is 0.5ng-TEQ/Nm³In contrast, the national standard requirement of waste incineration is 0.1, and even the requirement of some projects is 0.01.

(3) The conventional technology has poor emission reduction effect, the current hazardous waste flue gas emission standard in China is far from the similar household garbage incineration standard, and the requirement of upgrading and modifying is bound to face in the future. If the system of CN109185897B is adopted, the whole process chain is too long and still cannot solve the problems of energy utilization, corrosion, blockage and the like.

(4) The prior art is not stable enough, the concentration of the smoke pollutants is greatly changed due to the complicated and variable nature of the hazardous waste, and the prior art obviously cannot bear the large fluctuation of the pollutants, for example, aiming at the high-chlorine hazardous waste, a more-process and more-efficient system like CN109185897B is needed.

(5) The adoption of dry deacidification leads to great increase of the fly ash amount, while the fly ash collected by a single dust remover has dust in flue gas and deacidification byproducts, which can only be regarded as dangerous waste, and the treatment cost is greatly increased.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the hazardous waste incineration system and the operation process thereof, which have strong adaptability to hazardous waste, effectively solve the problem of dioxin regeneration, simultaneously improve the energy utilization rate of the system, shorten the length of a process chain and realize ultralow emission of flue gas of the hazardous waste.

The invention is realized by the following technical scheme:

a hazardous waste incineration system comprises a hazardous waste incinerator, a primary waste heat boiler, a high-temperature dust remover, a secondary waste heat boiler, a dry deacidification system, a medium-high temperature dust removal-denitration and dioxin removal device, an economizer, a GGH flue gas heat exchanger, a wet deacidification system, an induced draft fan and a chimney;

the hazardous waste incinerator is sequentially connected with the primary waste heat boiler, the high-temperature dust remover, the secondary waste heat boiler, the medium-high temperature dust removal-denitration and dioxin removal device, the economizer and the GGH flue gas heat exchanger through a flue;

the dry deacidification system is arranged between the secondary waste heat boiler and the medium-high temperature dedusting-denitration and dioxin removal device through a flue;

the GGH flue gas heat exchanger comprises a flue gas inlet, a hot flue gas port, a cold flue gas port and a flue gas outlet, the coal economizer is connected to the flue gas inlet of the GGH flue gas heat exchanger through a flue, the hot flue gas port of the GGH flue gas heat exchanger is connected to the wet deacidification system through the flue, the wet deacidification system is connected back to the cold flue gas port of the GGH flue gas heat exchanger through the flue, and the flue gas outlet of the GGH flue gas heat exchanger is connected with the induced draft fan through the flue;

the induced draft fan is connected to the chimney through the flue.

Preferably, the system further comprises an incineration fly ash disposal system, and the hazardous waste incinerator, the primary waste heat boiler and the high-temperature dust remover are respectively provided with a flue connected to the incineration fly ash disposal system.

Preferably, the system further comprises an ammonia injection system, wherein the ammonia injection system is arranged between the primary waste heat boiler and the high-temperature dust remover; or between the high-temperature dust remover and the secondary waste heat boiler; or the device is arranged between the secondary waste heat boiler and the medium-high temperature dust removal-denitration and dioxin removal device.

Preferably, the system further comprises a deacidification ash circulation system and a deacidification ash resource utilization system, wherein the deacidification ash circulation system and the deacidification ash resource utilization system are both connected with the medium-high temperature dedusting-denitration-dioxin removal device, and the deacidification ash circulation system is connected between the secondary waste heat boiler and the medium-high temperature dedusting-denitration-dioxin removal device through a flue.

Preferably, the system further comprises a waste heat utilization device, and the economizer is additionally provided with a flue which is sequentially connected with the secondary waste heat boiler and the primary waste heat boiler and is finally connected to the waste heat utilization device.

Preferably, the high-temperature dust remover is a high-temperature ceramic dust remover or a high-temperature metal dust remover.

Preferably, the medium-high temperature dust removal-denitration and dioxin removal device is an integrated device or a split design of a medium-high temperature dust removal device and an SCR denitration and dioxin removal device; the filter element of the medium-high temperature dust removal-denitration and dioxin removal device is made of ceramic or metal.

An operation process of a hazardous waste incineration system comprises the following steps:

step 1) after entering a hazardous waste incineration system, hazardous waste firstly enters a hazardous waste incinerator for incineration, the hazardous waste incinerator also comprises a secondary combustion chamber, the incineration temperature is higher than 1100 ℃, the smoke retention time is 2s, and therefore the yield of dioxin is reduced;

recovering heat of the high-temperature flue gas after incineration in the step 2) through a primary waste heat boiler, cooling to about 550 ℃, entering a high-temperature dust remover, and intercepting and removing most of dust in the flue gas;

step 3), enabling the dedusted flue gas to enter a secondary waste heat boiler, and recovering waste heat again, wherein the temperature of the flue gas is reduced to 250-300 ℃;

step 4) enabling the flue gas with the temperature of 250-300 ℃ to enter a medium-high temperature dedusting-denitration and dioxin-removing device, and spraying a deacidification agent through a dry deacidification system to react with the acid gas in the flue gas, so that the concentration of the acid gas is reduced, and the corrosion risk is reduced; the medium-high temperature dedusting-denitration and dioxin-removal device is also used as a deacidification reaction container;

the medium-high temperature dust removal-denitration and dioxin removal device is provided with a filter element, and a catalyst is covered on the filter element; dedusting by a filter element, collecting fly ash generated by a dry method, and ensuring that the dust reaches the standard; the catalyst simultaneously catalyzes and denitrates and removes dioxin, so that the dioxin is completely decomposed;

step 6) after passing through a medium-high temperature dust removal-denitration and dioxin removal device, the flue gas is subjected to denitration, dioxin removal, dust removal and partial deacidification, enters an economizer and is further recycled for residual energy, and the temperature of the flue gas is reduced to about 200 ℃;

step 7), allowing the flue gas at about 200 ℃ to pass through a GGH flue gas heat exchanger and then enter a wet deacidification system, removing the residual acid gas and refluxing to the GGH flue gas heat exchanger, wherein the GGH flue gas heat exchanger exchanges heat between the high-temperature flue gas before wet treatment and the low-temperature flue gas after wet treatment; in the high-temperature section, the temperature of the flue gas is reduced from 200 ℃ to about 100 ℃ and then the flue gas enters a wet deacidification system; in the low-temperature section, the flue gas at about 60 ℃ coming out of the wet deacidification system is heated to about 160 ℃; the flue gas before and after the wet method realizes non-contact heat exchange in the GGH flue gas heat exchanger;

and 8) finally, enabling the flue gas which flows back to the GGH flue gas heat exchanger through the wet deacidification system to enter an induced draft fan through a flue gas outlet, and discharging the clean flue gas into the atmosphere through a chimney through the induced draft fan after the clean flue gas reaches the standard.

Preferably, the method further comprises the following steps of 9), 10), 11) and 12):

step 9), taking ash generated by the hazardous waste incinerator, the primary waste heat boiler and the high-temperature dust remover as hazardous waste, and performing harmless treatment in an incineration fly ash disposal system;

step 10) spraying a reactant for SCR denitration into the flue gas by an ammonia spraying system, and evaporating by utilizing the heat of the high-temperature flue gas to generate NH₃With NO in the presence of a catalyst_xReacting to produce harmless N₂(ii) a The injection point of the ammonia injection system can be selected between a first-stage waste heat boiler and a high-temperature dust remover, between the high-temperature dust remover and a second-stage waste heat boiler or between the second-stage waste heat boiler and a medium-high temperature dust removal-denitration and dioxin removal device;

step 11), circulating a part of the collected deacidification fly ash to the medium-high temperature dedusting-denitration and dioxin-removing device through a deacidification ash circulating system for further deacidification, so that the deacidification efficiency is improved, and the utilization rate of the deacidification agent is improved; the rest part is subjected to resource utilization through a deacidification ash resource utilization system;

and step 12) the primary waste heat boiler, the secondary waste heat boiler and the economizer recover the energy of the flue gas to a waste heat utilization device to realize waste heat utilization in a mode of heating steam by using the waste heat of the flue gas.

The invention has the following beneficial effects:

(1) dust removal is carried out at a high-temperature section, so that the resynthesis of dioxin in a low-temperature region is avoided. Therefore, a quench tower is not needed, the residual heat of the flue gas can be recycled, and the problems of corrosion, blockage and the like caused by water spray quenching are avoided. The reason why the hazardous waste dioxin is high is that the hazardous waste dioxin is resynthesized at about 200-550 ℃, and the fly ash is a main reactant and a catalyst source for the dioxin resynthesizing, so that the fly ash in the flue gas is almost completely removed at a high temperature, the resynthesizing of the dioxin is greatly reduced, and a quench tower is avoided.

(2) After the high-temperature section removes dust, the dust content in the flue gas is greatly reduced, and the abrasion of the flue gas to subsequent equipment is reduced.

(3) By adopting a medium-high temperature denitration technology, the denitration efficiency is higher, and ultralow emission is realized. Because the denitration temperature is high, and arrange behind high temperature ceramic dust remover, consequently need not to heat the flue gas, also need not to worry ammonium bisulfate or alkali metal poisoning risk, the system operation cost is low, the efficient and the longe-lived of catalyst.

(4) The two-stage dust remover is arranged to separate fly ash with high smoke toxicity from nontoxic and harmless deacidification ash, the fly ash is treated as hazardous waste, and the deacidification ash can be recycled. Compared with the conventional scheme (the two schemes are mixed to cause that both the fly ash and the fly ash are treated as hazardous waste), the scheme effectively reduces the yield of the fly ash as the hazardous waste.

(5) A catalytic dioxin removal device is arranged instead of activated carbon injection, so that on one hand, dioxin is removed more thoroughly; on the other hand, avoid spouting the active carbon and lead to producing the danger again useless.

(6) Set up multistage waste heat utilization system, the flue gas heat after burning obtains the maximize recovery, improves the economic benefits of burning factory. Compared with the conventional hazardous waste incineration system which needs quenching to cause that the flue gas waste heat at 200-550 ℃ can not be utilized, the system can almost fully utilize the flue gas waste heat.

(7) The GGH system is arranged before the wet process, so that the finally discharged flue gas has higher temperature, the corrosion of the flue gas to a draught fan and a chimney is reduced, the diffusivity of the flue gas is also improved, the landing concentration of pollutants is reduced, and the harm of the pollutants to the environment is reduced.

(8) SCR denitration is used instead of SNCR, so that ammonia escape is low, and excessive ammonia, HCl and the like in the flue gas are prevented from generating ammonium chloride and other aerosols under the low-temperature condition, and dust exceeds the standard.

(9) The multi-stage series connection mode is adopted, two-stage deacidification and two-stage dust removal are carried out, dioxin is removed in two stages, the flue gas purification efficiency is high, the adaptability to raw materials is strong, and ultralow emission is realized.

Drawings

FIG. 1 is a process flow diagram of a hazardous waste incineration system of the present invention;

FIG. 2 is a partial enlarged view of a GGH flue gas heat exchanger;

in the figure: 1. a hazardous waste incinerator; 2. a primary exhaust-heat boiler; 3. a high temperature dust remover; 4. a secondary waste heat boiler; 5. a dry deacidification system; 6. a middle-high temperature dust removal-denitration and dioxin removal device; 7. a coal economizer; 8. a GGH flue gas heat exchanger; 8-1, a flue gas inlet; 8-2, hot flue gas ports; 8-3, a cold flue gas port; 8-4, a flue gas outlet; 9. a wet deacidification system; 10. an induced draft fan; 11. a chimney; 12. an incineration fly ash disposal system; 13. an ammonia injection system; 14. a deacidification ash circulation system; 15. a deacidification ash resource utilization system; 16. a waste heat utilization device.

Detailed Description

The invention is described in further detail below with reference to specific embodiments and with reference to the following drawings.

Example 1

A hazardous waste incineration system is shown in figure 1 and comprises a hazardous waste incinerator 1, a primary waste heat boiler 2, a high-temperature dust remover 3, a secondary waste heat boiler 4, a dry deacidification system 5, a medium-high temperature dust removal-denitration and dioxin removal device 6, an economizer 7, a GGH flue gas heat exchanger 8, a wet deacidification system 9, an induced draft fan 10 and a chimney 11.

The hazardous waste incinerator 1 is sequentially connected with the primary waste heat boiler 2, the high-temperature dust remover 3, the secondary waste heat boiler 4, the medium-high temperature dust removal-denitration and dioxin removal device 6, the economizer 7 and the GGH flue gas heat exchanger 8 through a flue.

The dry deacidification system 5 is arranged between the secondary waste heat boiler 4 and the medium-high temperature dedusting-denitration and dioxin-removing device 6 through a flue.

As shown in fig. 2, the GGH flue gas heat exchanger 8 includes a flue gas inlet 8-1, a hot flue gas port 8-2, a cold flue gas port 8-3, and a flue gas outlet 8-4, the economizer 7 is connected to the flue gas inlet 8-1 of the GGH flue gas heat exchanger 8 through a flue, the hot flue gas port 8-2 of the GGH flue gas heat exchanger 8 is connected to the wet deacidification system 9 through a flue, the wet deacidification system 9 is connected back to the cold flue gas port 8-3 of the GGH flue gas heat exchanger 8 through a flue, and the flue gas outlet 8-4 of the GGH flue gas heat exchanger 8 is connected to the induced draft fan 10 through a flue.

The induced draft fan 10 is connected to the chimney 11 through a flue.

As shown in fig. 1, the system further comprises an incineration fly ash disposal system 12, and the hazardous waste incinerator 1, the primary waste heat boiler 2 and the high temperature dust collector 3 are respectively provided with a flue connected to the incineration fly ash disposal system 12.

As shown in fig. 1, the system further comprises an ammonia injection system 13, wherein the ammonia injection system 13 is arranged between the primary exhaust-heat boiler 2 and the high-temperature dust remover 3; or between the high-temperature dust remover 3 and the secondary waste heat boiler 4; or between the secondary exhaust-heat boiler 4 and the medium-high temperature dust removal-denitration and dioxin removal device 6.

As shown in fig. 1, the system further comprises a deacidification ash circulation system 14 and a deacidification ash resource utilization system 15, both of which are connected with the medium-high temperature dust removal-denitration and dioxin removal device 6, wherein the deacidification ash circulation system 14 is connected between the secondary waste heat boiler 4 and the medium-high temperature dust removal-denitration and dioxin removal device 6 through a flue.

As shown in fig. 1, the system further comprises a waste heat utilization device 16, and the economizer 7 is additionally provided with a flue which is sequentially connected with the secondary waste heat boiler 4 and the primary waste heat boiler 2 and is finally connected to the waste heat utilization device 16.

According to a preferable scheme, the high-temperature dust remover 3 can adopt a high-temperature ceramic dust remover and also can adopt other forms, such as a high-temperature metal dust remover, and only the requirements of high temperature resistance, corrosion resistance and high dust removal efficiency are met.

In a preferred embodiment, the medium-high temperature dust removal-denitration-dioxin removal device 6 only needs to have the functions of denitration, dioxin removal and dust removal, and can be an integrated device or a split design, such as a medium-high temperature dust removal device plus an SCR denitration-dioxin removal device. The filter element of the medium-high temperature dust removal-denitration and dioxin removal device 6 can adopt a ceramic process and can also adopt other materials such as metal and the like.

According to a preferable scheme, the waste heat utilization system can adopt waste heat boilers (a primary waste heat boiler 2 and a secondary waste heat boiler 4) and can also adopt other devices capable of recovering heat.

Example 2

The hazardous waste incineration system of embodiment 1 is used for carrying out waste incineration treatment, and as shown in fig. 1, the method comprises the following specific steps:

(1) after the dangerous waste (garbage) enters a dangerous waste incineration system, the dangerous waste incinerator 1 is firstly incinerated, the dangerous waste incinerator 1 further comprises a secondary combustion chamber, the incineration temperature is more than 1100 ℃, and the smoke retention time is 2s so as to reduce the yield of dioxin.

(2) The heat in the incinerated high-temperature flue gas is recovered by the primary waste heat boiler 2, the high-temperature flue gas is cooled to about 550 ℃ and enters the high-temperature dust collector 3 (high-temperature ceramic dust collector), the high-temperature ceramic dust collector adopts a ceramic filter element, the high-temperature ceramic dust collector has the characteristics of high dust collection efficiency, temperature resistance, corrosion resistance and the like, the dust collection efficiency is more than 99.9 percent, and most of dust in the flue gas can be intercepted and removed.

(3) And (4) allowing the dedusted flue gas to enter a secondary waste heat boiler 4, recovering waste heat again, and reducing the temperature of the flue gas to 250-300 ℃. Because the regeneration of the dioxin mainly depends on a chlorine source, a carbon source, a heavy metal catalyst and the like in the dust, the regeneration of the dioxin is greatly inhibited in the cooling process after the dust is removed at the temperature of more than 550 ℃, the rapid cooling is not needed, and the cooling and the energy recovery can be realized by adopting a conventional waste heat boiler.

(4) The flue gas with the temperature of 250-300 ℃ enters a medium-high temperature dedusting-denitration and dioxin-removing device 6, and deacidification agents such as calcium hydroxide or sodium bicarbonate are sprayed into the flue gas through a dry deacidification system 5 to react with acid gas in the flue gas, so that the concentration of the acid gas is reduced, and the corrosion risk is reduced. The medium-high temperature dust removal-denitration and dioxin removal device 6 is also used as a deacidification reaction container.

(5) The middle-high temperature dust removal-denitration and dioxin removal device 6 is provided with a catalytic ceramic filter element, and a catalyst is covered on the ceramic filter element. And (3) dedusting by using a filter element, and collecting fly ash generated by a dry method to ensure that the dust reaches the standard. The catalyst simultaneously catalyzes denitration and dioxin removal, the dioxin removal principle is complete decomposition, and the purification mode is the most thorough.

(6) After passing through the middle-high temperature dust removal-denitration and dioxin removal device 6, the flue gas is subjected to denitration, dioxin removal, dust removal and partial deacidification, enters the economizer 7 to further recover residual energy, and the temperature of the flue gas is reduced to about 200 ℃. At the moment, the content of pollutants in the flue gas, especially acid gas and dust, is greatly reduced, so that the risks of corrosion and blockage of rear-end equipment are greatly reduced.

(7) The flue gas with the temperature of about 200 ℃ passes through the GGH flue gas heat exchanger 8 and then enters the wet deacidification system 9, the residual acid gas is removed and flows back to the GGH flue gas heat exchanger 8, and the GGH flue gas heat exchanger 8 exchanges heat between the high-temperature flue gas before the wet process and the low-temperature flue gas after the wet process. In the high temperature section, the temperature of the flue gas is reduced from 200 ℃ to about 100 ℃, and then the flue gas enters the wet deacidification system 9, and in the low temperature section, the flue gas with the temperature of about 60 ℃ coming out of the wet deacidification system 9 is heated to about 160 ℃. The flue gas before and after the wet method realizes non-contact heat exchange in the GGH flue gas heat exchanger 8, greatly improves the diffusivity of flue gas emission, reduces the landing concentration of flue gas pollutants, and reduces the corrosion of the flue gas to the induced draft fan 10, the chimney 11 and the like.

(8) And finally, the flue gas which flows back to the GGH flue gas heat exchanger 8 through the wet deacidification system 9 enters an induced draft fan 10 through a flue gas outlet 8-4, and the clean flue gas is discharged into the atmosphere through a chimney 11 through the induced draft fan 10 after reaching the standard.

(9) The fly ash collected by the dangerous waste incinerator 1, the primary waste heat boiler 2 and the high-temperature dust collector 3 contains harmful substances such as more heavy metals, still belongs to dangerous waste, and needs to be collected in a unified way and specially treated. Therefore, the ash generated by the hazardous waste incinerator 1, the primary waste heat boiler 2 and the high-temperature dust collector 3 enters the incineration fly ash disposal system 12 for harmless treatment.

(10) The ammonia injection system 13 injects ammonia or urea and the like into the flue gas as reactants for SCR denitration, and NH is generated after evaporation by utilizing the heat of the high-temperature flue gas₃With NO in the presence of a catalyst_xReacting to produce harmless N₂. The injection point of the ammonia injection system 13 can be selected to be at a proper position (as shown in fig. 1, it can be arranged between the primary exhaust-heat boiler 2 and the high-temperature dust remover 3, or between the high-temperature dust remover 3 and the secondary exhaust-heat boiler 4, or between the secondary exhaust-heat boiler 4 and the middle-high temperature dust removal-denitration and dioxin removal device 6), if it is injected in front of the high-temperature dust remover 3, it is helpful to suppress the generation of dioxin, and the mixing of ammonia is more uniform. The SCR denitration has the advantages of high denitration efficiency, low reactant consumption, low ammonia escape and the like, and the catalytic dioxin removal can completely decompose dioxin, so that the SCR denitration is the most thorough dioxin emission reduction mode.

(11) Because the original flue gas is subjected to high-temperature dust removal, the dust content in the flue gas is extremely low, the fly ash collected by the medium-high temperature dust removal-denitration and dioxin removal device 6 is mainly a deacidification byproduct, and part of the fly ash can be circulated to the medium-high temperature dust removal-denitration and dioxin removal device 6 through the deacidification ash circulation system 14 to be further deacidified, so that the deacidification efficiency is improved, and the utilization rate of the deacidification agent is improved. The residual by-product components are single, the content of harmful heavy metals and dioxin is low, and the deacidification ash resource utilization system 15 can be used for resource utilization.

(12) The primary waste heat boiler 2, the secondary waste heat boiler 4 and the economizer 7 recover the energy of the flue gas to the waste heat utilization device 16 to realize waste heat utilization in a mode of heating steam by using the waste heat of the flue gas.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the spirit and scope of the present invention, and any modifications, equivalents, improvements, etc. made by those skilled in the art without departing from the design concept of the present invention shall fall within the protection scope of the present invention.