Odor and solid waste low-nitrogen coupling combustion treatment system

Abstract

The application discloses a low-nitrogen coupling combustion treatment system for garbage pit odor and solid garbage, which comprises a garbage pit, at least one odor incineration mechanism and a garbage incinerator, wherein the garbage pit is provided with an odor outlet, the odor incineration mechanism comprises an incineration chamber for burning waste gas, an odor inlet connected with the incineration chamber, a fuel inlet and a combustion odor outlet, the odor inlet is connected with the odor outlet of the garbage pit through an odor conveying pipeline, the fuel inlet is connected with a fuel source through a fuel conveying pipeline, and the combustion odor outlet is connected with a combustion air inlet of the garbage incinerator through a flue gas discharging pipeline, so as to use high-temperature low-oxygen flue gas discharged by the odor incineration mechanism as combustion air of the garbage incinerator, so that garbage incineration is carried out in a high-temperature low-oxygen environment, the generation of nitrogen oxides can be effectively reduced, the coking phenomenon of the garbage incinerator can be greatly prevented, the combustion efficiency is improved, and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of waste treatment, in particular to a waste pit odor and solid waste low nitrogen coupling combustion treatment system capable of treating odor and preventing coking of waste incineration and saving energy. BACKGROUND

[0002] In recent years, the amount of municipal waste has increased rapidly with the continuous increase in population, the acceleration of urbanization and the improvement of living standards. There are mainly three ways for the harmless disposal of municipal waste in China: landfill, incineration and composting. The disposal of municipal waste in China is mainly landfill, and the proportion of incineration and composting is relatively small, but the proportion of incineration is increasing every year. Compared with landfill, incineration has the advantages of volume reduction, weight reduction and energy reuse. If landfill is continued to be the main method, more and more cities will be surrounded by waste in the near future, which forces China to speed up the construction of waste incineration plants.

[0003] The waste in the municipal solid waste incineration plant will be stored and dried for a certain amount of time before incineration, so a certain amount of waste leachate will be produced. Waste leachate is a kind of high-concentration organic wastewater with complex composition, which is recognized as one of the most difficult wastewater to meet the standard in the world. The typical characteristics of waste leachate are high BOD and COD concentration, high heavy metal concentration, large variation in water quality and quantity, high ammonia nitrogen content and imbalance of microbial nutrients. It not only has a very foul and unpleasant odor, but also the relevant indicators are 10-100 times of the general municipal wastewater. If the municipal waste leachate is directly discharged into the environment, it will cause serious pollution to the surrounding soil and water, and plants cannot grow in the place where the waste leachate is discharged.

[0004] During the incineration of municipal solid waste, high-content dioxin and heavy metal fly ash will be deposited in the tail gas purification equipment. According to the "Standard for Pollution Control on Landfill of Municipal Solid Waste GB 16889-2008", it is clearly stipulated that the fly ash of municipal solid waste incineration belongs to hazardous waste, and the landfill requires that the moisture content of fly ash of municipal solid waste incineration is less than 30%, the content of dioxin is less than 3 ug TEQ / Kg, and the leaching toxicity of heavy metals is less than the corresponding standard value. In particular, dioxin (PCDD / Fs) is the general term for polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzofuran (PCDFs). It is considered as "the most toxic substance in the world", and its most harmful is the irreversible "three toxicities" of teratogenicity, carcinogenicity and mutagenicity; once it enters the biological body, it accumulates in the biological body fat layer and organs and almost cannot be excreted or degraded, causing accumulative poisoning and seriously affecting the surrounding ecological environment.

[0005] In addition, a large amount of organic waste gas is produced during the fermentation process of the waste pit storing waste, which has a very foul odor and seriously pollutes the surrounding environment. The existing waste pit organic waste gas treatment methods are as follows: Figure 1As shown, waste gas from the garbage pit is at a temperature of 20°C. It is then drawn through a heat exchanger and heated to approximately 220°C before being introduced into the incinerator for combustion. The 300°C steam generated by the fuel incinerator serves as the heat source for the heat exchanger. This treatment model has serious drawbacks. Waste gas is prone to leakage, polluting the surrounding environment and impacting the lives of nearby residents. Furthermore, the incineration process for organic waste gas consumes energy, resulting in no cost savings. Incinerators burn garbage at relatively low temperatures, producing high ash content and prone to coking on the furnace walls, which reduces the incinerator's service life and efficiency. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned existing technologies and provide a garbage pit odor and solid waste low-nitrogen coupled combustion treatment system that can effectively remove garbage pit odor pollution while reducing coking in garbage incinerators, and is energy-saving and easy to implement.

[0007] To achieve the above-mentioned objectives, the present invention provides a garbage pit odor and solid waste low-nitrogen coupled combustion treatment system, which comprises: a garbage pit, at least one odor incineration mechanism and a garbage incinerator, wherein the garbage pit is provided with an odor outlet, and the odor incineration mechanism comprises: an incineration chamber for burning waste gas, an odor inlet connected to the incineration chamber, a fuel inlet and a combustion odor outlet, the odor inlet is connected to the odor outlet of the garbage pit through an odor conveying pipe, the fuel inlet is connected to the fuel source through a fuel conveying pipe, and the combustion odor outlet is connected to the combustion air inlet of the garbage incinerator through a flue gas exhaust pipe, so as to quote the high-temperature, low-oxygen flue gas discharged by the odor incineration mechanism as the combustion air of the garbage incinerator.

[0008] Optionally, a hot air duct is provided between the odor incineration mechanism and the waste incinerator, and the hot air duct is provided with an air inlet, a first air outlet and a second air outlet, wherein the air inlet is connected to the odor incineration mechanism; the first air outlet is connected to the chimney through a first exhaust duct, and a valve is provided on the first exhaust duct; the second air outlet is connected to the combustion air inlet of the waste incinerator through the second exhaust duct to quote the high-temperature and low-oxygen flue gas discharged by the odor incineration mechanism as the combustion air of the waste incinerator.

[0009] Optionally, the hot air duct is provided with a regulating air inlet, to which a fan is connected for introducing air and regulating the flue gas temperature and oxygen content, so that the flue gas temperature is controlled at about 220°C and the oxygen content is controlled at about 15-18%, which can effectively reduce the generation of nitrogen oxides in the waste incinerator and prevent coking.

[0010] Optionally, a first heat exchanger is provided between the odor incineration mechanism and the hot air pipe, the first heat exchanger being provided with a high-temperature gas inlet, a medium-temperature gas outlet, an odor inlet, and an odor exhaust outlet, and the odor incineration mechanism is also provided with an odor branch inlet; the high-temperature gas inlet is connected to the combustion odor outlet of the odor incineration mechanism, the medium-temperature gas outlet is connected to the air inlet of the hot air pipe, the odor inlet is connected to the odor outlet of the garbage pit through an odor branch pipe, and the odor exhaust outlet of the first heat exchanger is connected to the odor branch inlet of the odor incineration mechanism through a pipe, thereby the first heat exchanger draws out part of the odor in the garbage pit, and in the first heat exchanger, the flue gas with a temperature of up to 800°C generated by the odor incineration mechanism is heated into hot odor with a temperature of more than 500°C, and then introduced into the odor incineration mechanism for mixed combustion with the fuel.

[0011] Preferably, a main valve is installed on the odor transport pipeline, and auxiliary valves are installed on the odor branch pipeline. When the device is initially running, the main valve is opened and the auxiliary valve is closed. After the system has been running for a while, the main valve is closed and the auxiliary valve is opened. If a problem arises in the odor branch pipeline and requires maintenance, the auxiliary valve is closed and the main valve is opened. In this case, the odor is directly burned without heating. Although this wastes some energy, the device can continue to operate normally without shutting down.

[0012] Optionally, the garbage pit odor and solid waste low-nitrogen coupled combustion treatment system is provided with at least two odor incineration mechanisms, which are switched when in use. When one of the odor incineration mechanisms is damaged or needs maintenance, the other odor incineration mechanism can be switched to operate, so that the waste gas can be treated uninterruptedly to reduce pollution and danger.

[0013] Optionally, the garbage pit odor and solid waste low-nitrogen coupled combustion treatment system is provided with three odor incineration mechanisms, and during operation, two of the odor incineration mechanisms are in operation and the other one is on standby.

[0014] Optionally, a second heat exchanger is further included, which includes: a cold air inlet, a hot air outlet, a hot steam inlet, and a condensed water outlet; the hot air duct is also provided with an air inlet, which is connected to the hot air outlet of the second heat exchanger, and the hot steam inlet of the second heat exchanger is connected to the steam exhaust system of the steam turbine. Thus, the second heat exchanger uses the waste heat of steam exhaust from the steam turbine in the steam exhaust system of the steam turbine to preheat the air, and then the hot air enters the hot air duct and mixes with the flue gas.

[0015] Optionally, the steam turbine steam exhaust system includes a steam turbine, a deaerator, and a gas separator connected in sequence, and the gas outlet of the gas separator is connected to the hot steam inlet of the second heat exchanger.

[0016] Optionally, the gas distribution tank can also be provided with a branch outlet, which is connected to the inlet of the absorption refrigeration system, so that part of the heat is used for refrigeration, and the cold air produced is supplied to the office area of ​​the production workshop; the outlet of the absorption refrigeration system is connected to the inlet of the deaerator through a condensate pipe, so that the high-temperature condensate formed after refrigeration returns to the deaerator through the condensate pipe.

[0017] Optionally, a third heat exchanger is also included, which includes: a hot flue gas inlet, a cold flue gas outlet, a cold water inlet and a steam outlet, the hot flue gas inlet is connected to the steam outlet of the waste incinerator, the cold flue gas outlet is connected to the chimney, the cold water inlet is connected to the cold water source, and a steam pipe is provided at the steam outlet, which is connected to the air inlet of the turbine of the turbine steam exhaust system through the steam pipe.

[0018] Compared with the prior art, the advantages and beneficial effects of the present invention include: (1) pollution reduction: the waste gas from the garbage pit can be completely treated to avoid leakage and pollution of the environment; (2) energy saving: the waste heat is fully recovered and utilized, effectively saving energy consumption; (3) low operating cost: the waste heat is recovered and utilized, and the system transformation and operation management are simple and low-cost; (4) the high-temperature and low-oxygen flue gas emitted by the odor incineration mechanism is used as the combustion air of the garbage incinerator, so that the garbage incineration is carried out in a high-temperature and low-oxygen environment, which can effectively reduce the generation of nitrogen oxides, thereby preventing the garbage incinerator from coking to a great extent, improving the combustion efficiency, and extending the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a garbage pit odor treatment system in the prior art.

[0020] Figure 2 This is a structural schematic diagram of the first embodiment of the garbage pit odor and solid waste low-nitrogen coupled combustion treatment system of the present invention.

[0021] Figure 3 This is a structural schematic diagram of the second embodiment of the garbage pit odor and solid waste low-nitrogen coupled combustion treatment system of the present invention.

[0022] Figure 4 This is a structural schematic diagram of a third embodiment of the garbage pit odor and solid waste low-nitrogen coupled combustion treatment system of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The accompanying drawings show the specific structure of the preferred embodiment of the present invention. The structural features of each component, and if there is a description of the direction (up, down, left, right, front and back), it is based on Figure 1The structure shown is for reference description, but the actual application direction of the present invention is not limited thereto.

[0024] Please refer to Figure 2 As a non-limiting embodiment, the garbage pit odor and solid waste low-nitrogen coupled combustion treatment system provided by the present invention includes a garbage pit 10, three odor incineration mechanisms 20, three heat exchangers 30, a hot air pipe 40 and a garbage incinerator 50.

[0025] The garbage pit 10 is provided with an odor outlet 101 , and the odor incineration mechanism 20 includes: an incineration chamber 200 for burning odor, an odor inlet 201 connected to the incineration chamber 200 , a fuel inlet 202 , and a combustion odor outlet 203 .

[0026] The odor outlet 101 of the garbage pit 10 is connected to the odor inlet 201 of the odor incineration mechanism 20 through the odor conveying pipe L1. The odor conveying pipe L1 is provided with an exhaust fan P, so as to achieve the effect of extracting the odor in the garbage pit 10 into the odor incineration mechanism 20 for combustion.

[0027] The fuel inlet 202 of the odor incineration mechanism 20 is connected to a fuel source S via a fuel delivery pipeline L2. Fuel source S is natural gas, which has the advantages of high calorific value and low pollution. The fuel mixes with the heated odor and then burns at high temperatures within the incineration chamber 200, effectively incinerating the odor, eliminating environmental pollution and generating heat for utilization.

[0028] The combustion odor outlet 203 of the odor incineration mechanism 20 is connected to the hot air pipe 40 through the flue gas exhaust pipe L3, so that the high-temperature low-oxygen exhaust gas generated by the mixed combustion of fuel and odor is discharged into the hot air pipe. The hot air pipe 40 is provided with an air inlet 400, a first air outlet 401 and a second air outlet 402. Figure 2 As shown, the air inlet 400 is connected to the combustion odor outlet 203 of the odor incineration mechanism 20. The first exhaust port 401 is connected to the chimney Y through the first exhaust duct S1. The first exhaust duct S1 is provided with a valve F. Therefore, when the waste incinerator 50 does not need combustion air, the flue gas can be discharged directly through the chimney Y.

[0029] The hot air pipe 40 is connected to the combustion air inlet (not shown in the figure) of the garbage incinerator 50 through the second exhaust duct S2, and the high-temperature, low-oxygen flue gas discharged by the odor incineration mechanism 20 is used as the combustion air of the garbage incinerator 50. This can enable garbage incineration to be carried out in a high-temperature (not exceeding the upper limit temperature of the garbage incinerator) and low-oxygen environment, and can effectively reduce the production of nitrogen oxides and carbon monoxide, thereby preventing the garbage incinerator from coking to a great extent, improving combustion efficiency, and extending the life of the furnace body.

[0030] The hot air pipe 40 is also provided with a regulating air inlet 403, to which a regulating fan TP is connected for introducing air and regulating the flue gas temperature and oxygen content, so that the flue gas temperature is controlled at about 220°C and the oxygen content is controlled at about 15-18%, thereby effectively reducing the generation of nitrogen oxides in the waste incinerator and preventing coking.

[0031] In this non-limiting embodiment, Figure 2 As shown, a first heat exchanger 30 is provided between the odor incineration mechanism 20 and the hot air pipe 40. The first heat exchanger 30 is provided with a high-temperature gas inlet 301, a medium-temperature gas outlet 302, an odor inlet 303, and an odor outlet 304. The odor incineration mechanism 20 is also provided with an odor branch inlet 204.

[0032] The high-temperature gas inlet 301 of the first heat exchanger 30 is connected to the combustion odor outlet 203 of the odor incineration mechanism 20, the medium-temperature gas outlet 302 is connected to the air inlet 400 of the hot air pipe 40, the odor inlet 303 is connected to the odor outlet 101 of the garbage pit 10 through the odor branch pipe L4, and the odor exhaust port 304 is connected to the odor branch inlet 204 of the odor incineration mechanism 20 through a pipe. Thus, the odor in the garbage pit 10 is led out to the first heat exchanger 30, and the waste flue gas with a temperature of up to 800°C generated by the odor incineration mechanism 20 is heated to a hot air temperature of more than 500°C, and then introduced into the incineration chamber 200 to be mixed with the fuel for combustion. The odor is burned after being heated, which not only saves energy, but also improves the combustion efficiency of the odor incineration mechanism 20, reduces the external fuel consumption of the odor incineration mechanism 20, and achieves the purpose of recycling most of the waste heat of the exhaust gas.

[0033] Therefore, valve V1 is installed on odor delivery pipe L1, and valve V4 is installed on odor branch pipe L4. When the system first starts running, valve V1 is opened and valve V4 is closed. After the system has been running for a while, valve V1 is closed and valve V4 is opened. If a problem occurs in odor branch pipe L4 and requires maintenance, valve V4 is closed and valve V1 is opened. In this case, the odor is directly burned without heating. Although this wastes some energy, the system can still operate normally without shutting down.

[0034] In this non-limiting embodiment, more than two odor incineration mechanisms 20 are provided, which are switched when in use. When one of the odor incineration mechanisms is damaged or needs maintenance, another odor incineration mechanism can be switched to operate, so that the odor can be treated uninterruptedly and the risk of pollution and leakage can be reduced.

[0035] In the present invention, three odor incineration mechanisms 20 are provided, with a heat exchanger 30 positioned between each odor incineration mechanism 20 and the hot air pipe 40. The garbage pit 10 is equipped with three odor outlets 101, each connected to one of the three heat exchangers 30 via a branch line L4. The odor outlet 304 of each heat exchanger 30 is connected to the fuel inlet 202 of the corresponding odor incineration mechanism 20 via a pipe. Thus, when the entire system is in operation, two of the odor incineration mechanisms 20 can be in operation, while the other is in standby. This ensures thorough odor treatment, minimizes pollution, and provides sufficient low-oxygen, high-temperature exhaust gas for combustion in the garbage incinerator.

[0036] As another non-limiting embodiment, Figure 3 As shown, the second heat exchanger 60 is also included, and the second heat exchanger 60 includes a cold air inlet 601, a hot air outlet 602, a hot steam inlet 603, and a condensed water outlet 604. The hot air pipe 40 is provided with an air inlet 404, which is connected to the hot air outlet 602 of the second heat exchanger 60. The hot steam inlet 603 of the second heat exchanger 60 is connected to the steam turbine exhaust system 70, thereby utilizing the waste heat of steam discharged from the gas separator 703 in the steam turbine exhaust system 70 to preheat the air. The hot air then enters the hot air pipe 40 and mixes with the high-temperature, low-oxygen flue gas (exhaust gas). This effectively recovers the waste heat of steam discharged from the gas separator 703, further recycling energy.

[0037] like Figure 3 As shown, the steam turbine steam exhaust system 70 includes a steam turbine 701, a deaerator 702, and a gas separator 703, which are connected in sequence. The gas outlet 7031 of the gas separator 703 is connected to the hot steam inlet 603 of the second heat exchanger 60. As a result, steam from the steam turbine 701 passes through the deaerator 702 and then enters the gas separator 703, effectively recycling waste heat from the steam turbine exhaust system and saving energy. As a simplification, the steam turbine exhaust port can be directly connected to the gas separator, eliminating the deaeration step. As a non-limiting embodiment, a first switch valve (not shown) can be set on the pipeline connecting the gas separator 703 and the turbine 701 near the gas separator 703, and a second switch valve (not shown) can be set on the pipeline connecting the deaerator 702 and the turbine 701 near the deaerator 702. When the deaerator 702 is required to work, the second switch valve is opened and the first switch valve is closed at the same time. When the deaerator 702 is not required to work, the first switch valve is opened and the second switch valve is closed at the same time.

[0038] In this non-limiting embodiment, gas distributor 703 can be provided with a branch outlet 7032, which is connected to the inlet (not shown) of absorption refrigeration system 90, thereby utilizing some of the heat for cooling, with the resulting cold air being supplied to the production workshop and office areas. The outlet (not shown) of absorption refrigeration system 90 is connected to the inlet (not shown) of deaerator 702 via condensate pipe Z2, allowing the high-temperature condensate formed after cooling to return to deaerator 702 via condensate pipe Z2.

[0039] As another non-limiting embodiment, Figure 4 As shown, the system also includes a third heat exchanger 80, which includes: a hot flue gas inlet 801, a cold flue gas outlet 802, a cold water inlet 803 and a steam outlet 804. The hot flue gas inlet 801 is connected to the flue gas outlet (unnumbered) of the waste incinerator 50, the cold flue gas outlet 802 is connected to the chimney (not shown in the figure), and the cold water inlet 803 is connected to the cold water source (not shown in the figure). A steam pipe Z1 is provided at the steam outlet 804, and the steam pipe Z1 is connected to the steam inlet (unnumbered) of the turbine 701 of the turbine steam exhaust system 70, so that the steam generated by the heat burned in the waste incinerator 50 can be input into the turbine for power generation. The third heat exchanger 80 can be used to adjust the steam temperature and pressure of the turbine.

[0040] The above are only preferred embodiments of the present invention and should not be used to limit the scope of implementation of the present invention. That is, simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the invention description are still within the scope of the patent of the present invention.

Claims

1. A garbage pit odor and solid waste low-nitrogen coupled combustion treatment system, comprising: A garbage pit, at least one odor incineration mechanism, and a garbage incinerator, characterized in that the garbage pit is provided with an odor outlet, the odor incineration mechanism comprises: an incineration chamber for burning odor, an odor inlet connected to the incineration chamber, a fuel inlet, and a combustion odor outlet, the odor inlet being connected to the odor outlet of the garbage pit via an odor delivery pipe, the fuel inlet being connected to a fuel source via a fuel delivery pipe, and the combustion odor outlet being connected to the combustion air inlet of the garbage incinerator via a flue gas exhaust pipe; A hot air pipe is provided between the odor incineration mechanism and the waste incinerator, and the hot air pipe is provided with an air inlet, a first air outlet, and a second air outlet, wherein the air inlet is connected to the odor incineration mechanism; the first air outlet is connected to the chimney through a first exhaust duct, and the first exhaust duct is provided with a valve; the second air outlet is connected to the combustion air inlet of the waste incinerator through a second exhaust duct to quote the high-temperature, low-oxygen flue gas discharged by the odor incineration mechanism as the combustion air of the waste incinerator; The hot air pipe is also provided with a regulated air inlet, to which a fan is connected to regulate the flue gas temperature and oxygen content, so that the flue gas temperature is controlled at 220°C and the oxygen content is controlled at 15-18%, thereby effectively reducing the generation of nitrogen oxides in the waste incinerator and preventing coking; A first heat exchanger is provided between the odor incineration mechanism and the hot air pipe. The first heat exchanger is provided with a high-temperature gas inlet, a medium-temperature gas outlet, an odor inlet, and an odor exhaust outlet. The odor incineration mechanism is also provided with an odor branch inlet; the high-temperature gas inlet is connected to the combustion odor outlet of the odor incineration mechanism, the medium-temperature gas outlet is connected to the air inlet of the hot air pipe, the odor inlet is connected to the odor outlet of the garbage pit through an odor branch pipe, and the odor exhaust outlet of the first heat exchanger is connected to the odor branch inlet of the odor incineration mechanism through a pipe.

2. The garbage pit odor and solid waste low-nitrogen coupled combustion treatment system according to claim 1 is characterized in that: The garbage pit odor and solid waste low-nitrogen coupled combustion treatment system is provided with at least two odor incineration mechanisms.

3. The garbage pit odor and solid waste low-nitrogen coupled combustion treatment system according to claim 2 is characterized in that: The garbage pit odor and solid waste low-nitrogen coupled combustion treatment system is provided with three odor incineration mechanisms.

4. The garbage pit odor and solid waste low-nitrogen coupled combustion treatment system according to claim 3 is characterized in that: It also includes a second heat exchanger, which includes: a cold air inlet, a hot air outlet, a hot steam inlet, and a condensed water outlet; the hot air pipe is also provided with an air inlet, which is connected to the hot air outlet of the second heat exchanger, and the hot steam inlet of the second heat exchanger is connected to the turbine steam exhaust system.

5. The garbage pit odor and solid waste low-nitrogen coupled combustion treatment system according to claim 4 is characterized in that: The steam turbine steam exhaust system includes a steam turbine, a deaerator, and a gas separator connected in sequence, and the gas outlet of the gas separator is connected to the hot steam inlet of the second heat exchanger.

6. The garbage pit odor and solid waste low-nitrogen coupled combustion treatment system according to claim 5 is characterized in that: The gas separator is further provided with a branch outlet, which is connected to the inlet of the absorption refrigeration system; the outlet of the absorption refrigeration system is connected to the inlet of the deaerator through a condensed water pipe.

7. The garbage pit odor and solid waste low-nitrogen coupled combustion treatment system according to claim 6 is characterized in that: It also includes a third heat exchanger, which includes: a hot flue gas inlet, a cold flue gas outlet, a cold water inlet and a steam outlet, the hot flue gas inlet is connected to the steam outlet of the waste incinerator, the cold flue gas outlet is connected to the chimney, the cold water inlet is connected to the cold water source, and a steam pipe is provided at the steam outlet, and the steam outlet is connected to the air inlet of the turbine of the turbine steam exhaust system through the steam pipe.

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