Waste incineration power generation system based on pyrolysis gasification process

Abstract

According to the waste incineration power generation system based on the pyrolysis gasification technology, a pyrolysis gasification furnace is used for conducting waste pyrolysis gasification, generated combustible gas and biogas are mixed and then conveyed to a gas combustion chamber to be combusted, high-temperature flue gas with the high HCl content is generated, the high-temperature flue gas is led to an evaporator, and water is heated and converted into saturated steam; the residues are conveyed to a circulating fluidized bed incinerator to be mixed with auxiliary fuel for combustion, high-temperature flue gas with the low HCl content is generated, one path is led to a pyrolysis gasification furnace to provide heat for garbage pyrolysis gasification, the other path is led to a superheater to heat saturated steam, and generated superheated steam is conveyed to a steam turbine generator unit for power generation; high-temperature flue gas subjected to heat exchange through the evaporator and the superheater is mixed and enters a tail flue to utilize waste heat and finally enters a flue gas purification device. The method has the characteristics of being simple in principle, high in superheated steam parameter, high in heat energy utilization rate, high in reliability and the like, larger effective enthalpy drop is achieved, and the heat efficiency of a power generation system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste incineration power generation, in particular to a waste incineration power generation system based on pyrolysis gasification process. BACKGROUND

[0002] At present, the waste incinerator usually adopts medium-temperature and medium-pressure (4 MPa, 400℃) or medium-temperature and sub-high pressure (6.4 MPa, 450℃) main steam power generation, and the system efficiency of the power plant is low. This is mainly because the waste contains a large amount of PVC plastic and kitchen waste, which will produce a large amount of HCl gas during incineration, causing serious high-temperature corrosion of the metal heating surface and affecting the safe and stable operation of the equipment.

[0003] In the direct waste incineration power generation system, the content of HCl in the flue gas is high. Taking a waste incineration power plant as an example, the content of HCl in the original flue gas is 433.7-599.3 mg / m 3 When the flue gas passes through the pipe bundle with a pipe wall temperature exceeding 480℃, the chlorine corrosion reaction is intense, and the pipe will be quickly corroded, seriously affecting the service life of the equipment. In particular, the temperature of the superheated steam in the pipe is the key factor affecting the pipe wall temperature, in order to prevent the pipe wall temperature from exceeding 480℃, the waste incineration power plant generally limits the superheated steam temperature at the outlet of the high-temperature superheater to not exceed 450℃.

[0004] In the waste pyrolysis gasification incineration power generation system, the waste is heated to produce small molecule combustible gas under anaerobic or hypoxic conditions, and then the combustible gas is combusted under oxygen-rich conditions to produce high-temperature flue gas, which is used to generate steam and drive the steam turbine generator set to generate power. The pyrolysis and gasification of waste under anaerobic or hypoxic conditions can reduce the production of highly toxic pollutants such as dioxin; however, most of the waste incineration power generation systems based on pyrolysis gasification process do not pay special attention to the problem of HCl in the flue gas, similar to the direct waste incineration power generation system, the high-temperature chlorine corrosion of the heating surface still limits the improvement of the steam parameters of the system.

[0005] Most of the existing high-steam-parameter waste power generation technologies are based on common technologies, and use steam reheat to improve the pressure of the steam and increase the enthalpy of the steam, so as to realize greater effective enthalpy drop and improve the thermal cycle efficiency. However, the investment in reheat equipment needs to be increased, and the temperature of the superheated steam is still limited by the high-temperature corrosion of HCl.

[0006] In addition, the existing garbage pyrolysis gasification incineration power generation technology basically avoids the problem of high-temperature corrosion of HCl in the power generation system. According to the field project investigation, it is found that the existing garbage pyrolysis gasification process does not effectively solve the problem of high-temperature corrosion of HCl in the power generation system. Therefore, the steam parameters of the power generation system are still mainly medium-temperature and medium-pressure (4MPa, 400℃) and medium-temperature and sub-high pressure (6.4MPa, 450℃). Due to the limitation of temperature and pressure, the thermal cycle efficiency is relatively low. SUMMARY

[0007] The technical problem solved by the present application is to provide a garbage incineration power generation system based on a pyrolysis gasification process, which has a compact structure, is convenient to operate and has high stability.

[0008] In order to solve the above technical problems, the technical scheme adopted by the present application is: A garbage incineration power generation system based on a pyrolysis gasification process, comprising: a pyrolysis gasification furnace, a circulating fluidized bed incinerator, a gas combustion chamber, an evaporator, a superheater, a coal economizer, an air preheater, a steam turbine generator set and a flue gas purification device; the pyrolysis gasification furnace is used to realize the pyrolysis gasification of garbage under the condition of 650±50℃ and oxygen deficiency, and the generated combustible gas is transported to the gas combustion chamber, and the residue is transported to the circulating fluidized bed incinerator; the circulating fluidized bed incinerator is also connected with an auxiliary fuel storage bin, the auxiliary fuel storage bin is used to provide fuel containing low chlorine content and containing alkali metal components into the circulating fluidized bed incinerator, and the fuel is mixed with the residue of garbage pyrolysis for combustion; the high-temperature flue gas generated in the circulating fluidized bed incinerator is divided into two paths, one path leads to the pyrolysis gasification furnace to provide heat for the pyrolysis gasification of garbage, and the other path leads to the superheater to heat the saturated steam; the superheater is connected with the steam turbine generator set, and the superheated steam generated in the superheater enters the steam turbine generator set to generate power; the gas combustion chamber is also connected with a biogas storage tank, and the biogas storage tank is used to provide biogas to the gas combustion chamber for common combustion with the combustible gas generated by garbage pyrolysis, and the high-temperature flue gas generated in the gas combustion chamber is led to the evaporator to heat water into steam; the high-temperature flue gas mixed after heat exchange in the evaporator and the superheater is transported to the coal economizer, the feed water is heated through the coal economizer first, then the primary air is preheated through the air preheater, and finally the flue gas is purified through the flue gas purification device and discharged from the chimney.

[0009] As a further improvement of the present application, the temperature of the superheated steam at the outlet of the superheater is 540℃, and the pressure is 13.7MPa.

[0010] As a further improvement of the present application, the inlet of the pyrolysis gasifier is provided with a garbage hopper, the lower part of the garbage hopper is provided with a pusher, the pyrolysis gasifier is provided with a multi-stage grate, the upper part of the pyrolysis gasifier is provided with a pyrolysis gas outlet, and the outlet of the pyrolysis gasifier is provided with a slag falling pipe; the garbage falls from the garbage hopper, is pushed into the grate by the pusher for pyrolysis and gasification, the generated combustible gas enters the gas combustion chamber through the pyrolysis gas outlet, and the residue falls into the slag falling pipe.

[0011] As a further improvement of the present application, the lower part of the grate is provided with a slag falling hopper, the side of the slag falling hopper is provided with a high-temperature flue gas inlet connected with the high-temperature flue gas outlet of the circulating fluidized bed incinerator, the lower part of the slag falling hopper is provided with a slag falling conveyor connected with the slag falling pipe, and the lower part of the slag falling pipe is provided with a scraper conveyor for conveying the slag to the circulating fluidized bed incinerator.

[0012] As a further improvement of the present application, the scraper conveyor is provided between the circulating fluidized bed incinerator and a residue storage bin, the outlet end of the residue storage bin is provided with a crusher, and the outlet end of the crusher is connected to the circulating fluidized bed incinerator through a first feeder; the auxiliary fuel storage bin is provided between the circulating fluidized bed incinerator and a second feeder.

[0013] As a further improvement of the present application, the lower part of the circulating fluidized bed incinerator is provided with a wind distribution plate and a wind chamber, the wind chamber is connected to an air preheater through a pipeline, the preheated primary air is delivered to the wind chamber, and then enters the circulating fluidized bed incinerator through the wind distribution plate.

[0014] As a further improvement of the present application, the high-temperature flue gas outlet of the upper part of the circulating fluidized bed incinerator is connected to a cyclone separator, the gas outlet of the cyclone separator is connected to the pyrolysis gasifier and a superheater respectively, the solid outlet of the cyclone separator is connected to a return device connected to the circulating fluidized bed incinerator, so as to realize that the unburned particles separated by the cyclone separator are sent back to the circulating fluidized bed incinerator by the return device for further incineration.

[0015] As a further improvement of the present application, a gas mixer with dust removal function is provided between the pyrolysis gas outlet and the gas combustion chamber, the combustible gas generated by the pyrolysis gasifier and the biogas in the biogas storage tank are mixed uniformly in the gas mixer, and then enter the gas combustion chamber to mix with the air entering through the air inlet pipe and are ignited and burned by the burner in the gas combustion chamber.

[0016] As a further improvement of the present application, the top of the gas combustion chamber is provided with a spraying device for spraying leachate concentrate into the combustion chamber for incineration.

[0017] As a further improvement of the present application, the grate comprises high-temperature flue gas inlet holes arranged horizontally and compressed air inlet holes arranged vertically; the high-temperature flue gas generated by the circulating fluidized bed incinerator enters the pyrolysis gasifier through the high-temperature flue gas inlet holes to provide the required heat for the pyrolysis and gasification of the garbage and to disturb the garbage; the compressed air enters the pyrolysis gasifier through the compressed air inlet holes to push the garbage forward; and the interaction of the two kinds of gas can turn over the garbage and strengthen the heat and mass transfer.

[0018] Compared with the prior art, the present application has the following advantages: The garbage incineration power generation system based on the pyrolysis and gasification process of the present application can generate high-temperature flue gas with high HCl content by mixing and burning the mixed gas with high HCl content generated by the pyrolysis and gasification of the garbage and the biogas generated by the treatment of the garbage leachate in a certain proportion without increasing the reheating equipment, and the high-temperature flue gas sequentially passes through the heating surfaces such as evaporators, coal economizers and air preheaters, the temperature of the working medium in the tubes of these heating surfaces is not high, and the tube wall temperature is lower than 480 DEG C at which the chlorine corrosion is severe, so the service life of the equipment will not be seriously affected by the chlorine corrosion; the garbage pyrolysis and gasification residues and auxiliary fuel enter the fluidized bed incinerator for combustion to provide heat for the pyrolysis and gasification furnace and the superheater; and the auxiliary fuel is biomass particles such as wood, bamboo and rice husk or fuel with similar properties, which can supplement the insufficient heat supply of the pyrolysis and gasification residues alone and produce a large amount of alkali metal oxides or alkali metal salts during combustion due to the low chlorine content and the presence of a large amount of alkali metal components, thereby having strong dechlorination performance, so that the garbage residues are mixed and burned in the fluidized bed incinerator, and most of the chlorine-containing products are saved in the form of KCl or CaCl2, thereby further reducing the generation of HCl; since the HCl content in the flue gas is low, the high-temperature flue gas contacts the high-temperature superheater, even if the steam temperature at the outlet of the high-temperature superheater reaches 540 DEG C and the tube wall temperature exceeds 480 DEG C, the service life of the equipment will not be seriously affected by the chlorine corrosion; in the present application, the parameters of the superheated steam are improved to 13.7 MPa and 540 DEG C, so that the enthalpy of the steam is greatly improved, the work capacity is stronger, a larger effective enthalpy drop can be achieved, the high-temperature superheater can be prevented from being corroded by the flue gas with high HCl content, the main steam parameters can be improved, and thus the overall thermal efficiency of the power generation system is improved, and the power generation capacity per ton of garbage is increased. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The figure is a structural principle diagram of the garbage incineration power generation system based on the pyrolysis and gasification process in the specific embodiment of the present application; Figure 2 The figure is a structural principle diagram of the grate of the pyrolysis and gasification furnace in the specific embodiment of the present application; Legend: 1, pyrolysis gasifier; 2, circulating fluidized bed incinerator; 3, gas combustion chamber; 4, evaporator; 5, superheater; 6, coal economizer; 7, air preheater; 8, steam turbine generator set; 9, flue gas purification device; 10, chimney; 101, garbage hopper; 102, pusher; 103, grate; 1031, high-temperature flue gas inlet hole; 1032, compressed air inlet hole; 104, slag leakage hopper; 105, slag leakage conveyor; 106, slag falling pipe; 107, scraper conveyor; 108, pyrolysis gasification gas outlet; 201, residual slag storage bin; 202, auxiliary fuel storage bin; 203, crusher; 204, first feeder; 205, second feeder; 206, air distribution plate; 207, air chamber; 208, cyclone separator; 209, return device; 301, biogas storage tank; 302, gas mixer; 303, air inlet pipe; 304, burner; 305, injection device; 306, steam drum. DETAILED DESCRIPTION

[0020] The application will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the application is not limited thereby.

[0021] In the description of the application, it should be understood that the terms "side", "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0022] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implying the number of the indicated technical features, so that the features with "first" and "second" can include one or more of the features explicitly or implicitly, and in the description of the application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0023] EMBODIMENT Since about 80% of HCl produced by waste incineration comes from organic chlorine (mainly from PVC), and organic chlorine starts to release HCl gas at 200-360 ℃ and releases all at about 550 ℃. Therefore, under the condition of pyrolysis gasification of waste at 650±50 ℃ and oxygen deficiency, the mixed gas produced contains all the HCl released by organic chlorine and part of the HCl released by inorganic chlorine, that is, most of the HCl released by waste incineration is mixed with combustible gas and discharged, and the HCl content in the mixed gas is high; at the same time, a small amount of inorganic chlorine that can release HCl exists in the pyrolysis gasification residue.

[0024] As shown in Figure 1 The waste incineration power generation system based on the pyrolysis gasification process of the present application comprises a pyrolysis gasification furnace 1, a circulating fluidized bed incinerator 2, a gas combustion chamber 3, an evaporator 4, a superheater 5, an economizer 6, an air preheater 7, a steam turbine generator set 8 and a flue gas purification device 9. The pyrolysis gasification furnace 1 is used to realize the pyrolysis gasification of waste at about 650 ℃ and oxygen deficiency, and the combustible gas with high HCl content produced is delivered to the gas combustion chamber 3, and the residue is delivered to the circulating fluidized bed incinerator 2. The circulating fluidized bed incinerator 2 is also connected with an auxiliary fuel storage bin 202, and the auxiliary fuel storage bin 202 is used to provide fuel with low chlorine content and containing more alkali metal components into the circulating fluidized bed incinerator 2, which is mixed with the residue of waste pyrolysis and combusted to form high-temperature flue gas with low HCl content. On the one hand, the auxiliary fuel makes up for the insufficient heat supply of the pyrolysis gasification residue alone combustion, and on the other hand, the combustion of the auxiliary fuel will produce a large amount of alkali metal oxides or alkali metal salts, which have strong dechlorination performance, and the mixed combustion with the pyrolysis gasification residue saves most of the chlorine-containing products in the form of KCl or CaCl2, thereby further reducing the generation of HCl. The high-temperature flue gas produced in the circulating fluidized bed incinerator 2 is divided into two routes, one of which leads to the pyrolysis gasification furnace 1 to provide heat for waste pyrolysis gasification, and the other of which leads to the superheater 5 to heat saturated steam. The temperature of the superheated steam at the outlet of the superheater 5 is 540 ℃, and the pressure is 13.7 MPa. The superheater 5 is connected with the steam turbine generator set 8, and the superheated steam produced in the superheater 5 enters the steam turbine generator set 8 to generate electricity. The gas combustion chamber 3 is also connected with a biogas storage tank 301, and the biogas storage tank 301 is used to collect biogas produced by waste leachate treatment and provide biogas to the gas combustion chamber 3, which is combusted with the combustible gas produced by waste pyrolysis, and the high-temperature flue gas produced in the gas combustion chamber 3 leads to the evaporator 4 to heat water into steam. The high-temperature flue gas with high HCl content after heat exchange in the evaporator 4 is mixed with the high-temperature flue gas with low HCl content after heat exchange in the superheater 5 and delivered to the economizer 6, first heated to feed water, then preheated to primary air by the air preheater 7, realizes the cascade application of energy, and finally purified by the flue gas purification device 9 and discharged by the chimney 10.

[0025] In the present application, the mixed gas with high HCl content generated by waste pyrolysis gasification is mixed with biogas generated by waste leachate treatment in a certain proportion to produce high-temperature flue gas with high HCl content, which successively passes through the heating surfaces of the evaporator 4, the coal economizer 6, the air preheater 7, etc. to realize the cascade utilization of heat energy. According to theoretical calculation and engineering practice, the influence of flue gas temperature on the tube wall temperature of the heating surface is limited, and the working medium temperature is the key factor affecting the tube wall temperature of the heating surface. The saturated steam temperature under 13.7 MPa pressure is 329℃, so even if the steam pressure is set to 13.7 MPa, the temperature of the working medium at the outlet of the evaporator 4 is only 329℃, and the tube wall temperature of the evaporator 4 generally does not exceed 80℃ from the outlet working medium temperature, i.e. the tube wall temperature of the evaporator 4 is generally not more than 409℃, which is lower than the 480℃ at which the chlorine corrosion reaction is intense, and the service life of the equipment will not be seriously affected by chlorine corrosion. In addition, the working medium temperature in the tubes of the coal economizer 6 and the air preheater 7 is lower, and the equipment is less affected by chlorine corrosion.

[0026] As shown in Figure 1 , the inlet of the pyrolysis gasification furnace 1 is provided with a waste hopper 101, the lower part of the waste hopper 101 is provided with a pusher 102, the pyrolysis gasification furnace 1 is provided with a multi-stage grate 103, the upper part of the pyrolysis gasification furnace 1 is provided with a pyrolysis gasification gas outlet 108, and the outlet of the pyrolysis gasification furnace 1 is provided with a slag falling pipe 106. The waste falls from the waste hopper 101 and is pushed into the grate 103 by the pusher 102 for pyrolysis gasification, the generated combustible gas enters the gas combustion chamber 3 through the pyrolysis gasification gas outlet 108, and the residue falls into the slag falling pipe 106.

[0027] As shown in Figure 1 , a gas mixer 302 is arranged between the pyrolysis gasification gas outlet 108 and the gas combustion chamber 3. The biogas generated by the waste leachate treatment is purified and stored in a biogas storage tank 301, and then mixed with the combustible gas discharged from the pyrolysis gasification gas outlet 108 in the gas mixer 302 with dust removal function. On the one hand, it can complement each other, making the calorific value of the mixed gas more stable, which is conducive to the stable operation of the combustion equipment and improves the energy utilization efficiency; on the other hand, it can make full use of the energy of the two kinds of gas and improve the power generation capacity of the power generation equipment. The mixed gas enters the gas combustion chamber 3, mixes with the air entering through the air inlet pipe 303, is ignited and burned by the burner 304 to generate high-temperature flue gas with high HCl content, and leads to the evaporator 4 to heat and convert water into steam.

[0028] In the present embodiment, the top of the gas combustion chamber 3 is provided with a spraying device 305, which is used to spray the leachate concentrate into the gas combustion chamber 3 for incineration treatment, so as to realize the disposal of the leachate concentrate.

[0029] In the present embodiment, the evaporator 4 and the superheater 5 are both arranged in multiple stages for the reasons of optimizing heat exchange efficiency and reducing thermal deviation, etc.

[0030] In this embodiment, the feed water is heated by the coal economizer 6 and then enters the steam drum 306; the saturated steam is led out from the top of the steam drum 306 to the superheater 5, and the heated steam (13.7 MPa, 540℃) enters the steam turbine generator set 8 to generate electricity. The saturated water enters the heating surface of the evaporator 4 again to be heated to become a saturated steam-water mixture and then returns to the steam drum 306.

[0031] As shown in Figure 1 The slag chute 104 is provided below the grate 103, and a high-temperature flue gas inlet is provided on the side of the slag chute 104, which is connected with the high-temperature flue gas outlet of the circulating fluidized bed incinerator 2. A slag conveying machine 105 is provided below the slag chute 104, which is connected with the slag falling pipe 106. A scraper conveyor 107 is provided below the slag falling pipe 106, which is used to convey the slag to the circulating fluidized bed incinerator 2.

[0032] Further, a residual slag storage bin 201 is provided between the scraper conveyor 107 and the circulating fluidized bed incinerator 2, and a high-temperature-resistant crusher 203 is provided at the discharge end of the residual slag storage bin 201. The discharge end of the crusher 203 is connected with the circulating fluidized bed incinerator 2 through a first feeder 204. A second feeder 205 is provided between the auxiliary fuel storage bin 202 and the circulating fluidized bed incinerator 2.

[0033] In this embodiment, the slag collected by the slag chute 104 is first discharged through the discharge port to the slag conveying machine 105, then conveyed to the slag falling pipe 106 through the slag conveying machine 105, and finally enters the scraper conveyor 107 together with the garbage pyrolysis gasification residual slag and is conveyed to the residual slag storage bin 201. The residual slag in the residual slag storage bin 201 is crushed by the high-temperature-resistant crusher 203 and then sent into the circulating fluidized bed incinerator 2 by the first feeder 204. The fuel in the auxiliary fuel storage bin 202 is sent into the circulating fluidized bed incinerator 2 by the second feeder 205.

[0034] As shown in Figure 1 The circulating fluidized bed incinerator 2 is provided with a wind distribution plate 206 and an air chamber 207 at the lower part. The air chamber 207 is connected with the air preheater 7 through a pipeline, and the preheated primary air is conveyed to the air chamber 207 and then enters the circulating fluidized bed incinerator 2 through the wind distribution plate 206 to promote combustion. In other embodiments, the circulating fluidized bed incinerator 2 can also be replaced by a rotary bed incinerator or other incineration equipment that can achieve the same effect.

[0035] As shown in Figure 1As shown, the high-temperature flue gas outlet of the upper portion of the circulating fluidized bed incinerator 2 is connected to the cyclone separator 208, the gas outlet of the cyclone separator 208 is connected to the high-temperature flue gas inlet of the superheater 5 and the side of the slag tapping hole 104 respectively, and the solid outlet of the cyclone separator 208 is connected to the return device 209. The return device 209 is connected to the circulating fluidized bed incinerator 2 to realize that the unburned particles separated by the cyclone separator 208 are sent back to the circulating fluidized bed incinerator 2 by the return device 209 for continuous incineration.

[0036] In this embodiment, the auxiliary fuel is wood, bamboo, rice husk and other fuels with low chlorine content and containing a large amount of alkali metal components, which is mixed with the residual gasification residue of waste for combustion to produce high-temperature flue gas with low HCl content. The high-temperature flue gas is separated by the cyclone separator 208 to separate out the unburned particles, which are sent back to the circulating fluidized bed incinerator 2 by the return device 209 for continuous incineration; the high-temperature flue gas after separation of the unburned particles is divided into two paths by the adjusting baffle, one path leading to the pyrolysis gasification furnace 1 to provide heat for the pyrolysis gasification of waste, and the other path leading to the superheater 5 to heat the saturated steam.

[0037] In this embodiment, in order to protect the furnace wall material of the circulating fluidized bed incinerator 2 from high-temperature damage, the inner wall is provided with a water cooling pipe, and the inlet water is desalinated water, and the outlet water is discharged to the deaerator.

[0038] As shown, Figure 2 The grate 103 includes high-temperature flue gas inlet holes 1031 arranged in the horizontal direction and compressed air inlet holes 1032 arranged in the vertical direction. The high-temperature flue gas generated by the circulating fluidized bed incinerator 2 enters the pyrolysis gasification furnace 1 through the high-temperature flue gas inlet holes 1031 to provide the required heat for the pyrolysis gasification of waste and to disturb the waste. The compressed air enters the pyrolysis gasification furnace 1 through the compressed air inlet holes 1032 to push the waste forward and cooperate with the vertical disturbance of the high-temperature flue gas to overturn the waste and strengthen the heat and mass transfer. In this embodiment, the high-temperature flue gas output by the fluidized bed incinerator 2 not only provides heat for the pyrolysis gasification of waste, but also vertically disturbs the waste; the compressed air pushes the waste forward at a certain frequency and provides a small amount of oxygen for the pyrolysis gasification of waste; the interaction of the two gases can overturn the waste and strengthen the heat and mass transfer.

[0039] Due to the instability of the composition of waste, the heat provided by the pyrolysis gasification residue has fluctuation, which can be controlled by controlling the amount of auxiliary fuel added to ensure that the heat output by the fluidized bed incinerator 2 can meet the heat demand of the pyrolysis gasification furnace 1 and the superheater 5; at the same time, the amount of flue gas entering the pyrolysis gasification furnace 1 can be adjusted by means such as adjusting baffle to ensure that the temperature in the pyrolysis gasification furnace 1 is about 650°C, and the steam parameters entering the steam turbine generator set 8 are 13.7MPa and 540°C, and the system can be operated stably for a long time under this working condition.

[0040] In the embodiment, the pyrolysis gasification residues and auxiliary fuel enter the fluidized bed incinerator 2 to burn together, and provide heat for the pyrolysis gasification furnace 1 and the superheater 5. The auxiliary fuel is biomass particles such as wood, bamboo and rice husk or fuel with similar characteristics. On the one hand, it supplements the insufficient heat supply of the pyrolysis gasification residues alone burning, and on the other hand, wood, bamboo and rice husk contain low chlorine content and contain more alkali metal components, and combustion will produce a large amount of alkali metal oxides or alkali metal salts, which have strong dechlorination performance. In the fluidized bed incinerator 2, it is mixed and burned with the pyrolysis gasification residues, and most of the chlorine-containing products are saved in the form of KCl or CaCl2, thereby further reducing the generation of HCl. Therefore, the pyrolysis gasification residues containing less inorganic chlorine that can release HCl, the auxiliary fuel with strong dechlorination effect is added, and the HCl content of the high-temperature flue gas generated by mixed combustion is low, generally less than 50 mg / m 3 Similar to coal combustion. Due to the low HCl content in the flue gas, the high-temperature flue gas contacts the high-temperature superheater 5, even if the steam temperature at the outlet of the high-temperature superheater 5 reaches 540℃, and the pipe wall temperature exceeds 480℃, the service life of the equipment will not be seriously affected by chlorine corrosion.

[0041] The above is only the preferred embodiment of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical solutions falling within the concept of the present application shall fall within the protection scope of the present application. It should be noted that for ordinary skilled persons in the art, some improvements and decorations without departing from the principles of the present application shall also be considered as the protection scope of the present application.

Claims

1. A waste incineration power generation system based on pyrolysis and gasification process, characterized in that: include: A pyrolysis gasification furnace (1), a circulating fluidized bed incinerator (2), a gas combustion chamber (3), an evaporator (4), a superheater (5), an economizer (6), an air preheater (7), a steam turbine generator set (8) and a flue gas purification device (9); the pyrolysis gasification furnace (1) is used to realize pyrolysis and gasification of garbage at 650±50°C under an oxygen-deficient condition, and the generated combustible gas is transported to the gas combustion chamber (3), and the residue is transported to the circulating fluidized bed incinerator (2); the circulating fluidized bed incinerator (2) is also connected to an auxiliary fuel storage bin (202), and the auxiliary fuel storage bin (202) is used to provide fuel with a low chlorine content and containing alkali metal components to the circulating fluidized bed incinerator (2), and the fuel is used to be oxidized by the pyrolysis of garbage. The residues are mixed and burned; the high-temperature flue gas generated in the circulating fluidized bed incinerator (2) is divided into two paths, one path is led to the pyrolysis gasification furnace (1) to provide heat for the pyrolysis and gasification of garbage, and the other path is led to the superheater (5) to heat saturated steam; the superheater (5) is connected to the steam turbine generator set (8), and the superheated steam generated in the superheater (5) enters the steam turbine generator set (8) to generate electricity; the gas combustion chamber (3) is also connected to the biogas storage tank (301), and the biogas storage tank (301) is used to provide biogas to the gas combustion chamber (3) for co-combustion with the combustible gas generated by the pyrolysis of garbage, and the high-temperature flue gas generated in the gas combustion chamber (3) is led to the evaporator (4) for heating water and converting it into saturated steam; The high-temperature flue gas after heat exchange in the evaporator (4) is mixed with the high-temperature flue gas after heat exchange in the superheater (5) and then transported to the economizer (6). The high-temperature flue gas first heats the feed water in the economizer (6), then preheats the primary air in the air preheater (7), and finally is purified by the flue gas purification device (9) and discharged from the chimney (10).

2. The waste incineration power generation system based on pyrolysis gasification process according to claim 1 is characterized in that: The temperature of the superheated steam at the outlet of the superheater (5) is 540°C and the pressure is 13.7 MPa.

3. The waste incineration power generation system based on pyrolysis gasification process according to claim 2 is characterized in that: The pyrolysis gasification furnace (1) is provided with a garbage hopper (101) at the inlet, a pusher (102) at the lower part of the garbage hopper (101), a multi-stage grate (103) is provided in the pyrolysis gasification furnace (1), a pyrolysis gasification gas outlet (108) is provided at the upper part of the pyrolysis gasification furnace (1), and a slag drop pipe (106) is provided at the discharge port of the pyrolysis gasification furnace (1); garbage falls from the garbage hopper (101) and is pushed onto the grate (103) by the pusher (102) for pyrolysis and gasification, and the generated combustible gas enters the gas combustion chamber (3) through the pyrolysis gasification gas outlet (108), and the residue falls into the slag drop pipe (106).

4. The waste incineration power generation system based on pyrolysis gasification process according to claim 3 is characterized in that: A slag hopper (104) is provided below the grate (103), a high-temperature flue gas inlet is provided on the side of the slag hopper (104), and the high-temperature flue gas inlet is connected to the high-temperature flue gas outlet of the circulating fluidized bed incinerator (2). A slag conveyor (105) is provided below the slag hopper (104), and the slag conveyor (105) is connected to a slag dropping pipe (106). A scraper conveyor (107) is provided below the slag dropping pipe (106), and the scraper conveyor (107) is used to convey the slag to the circulating fluidized bed incinerator (2).

5. The waste incineration power generation system based on pyrolysis gasification process according to claim 4 is characterized in that: A residue storage bin (201) is provided between the scraper conveyor (107) and the circulating fluidized bed incinerator (2); a crusher (203) is provided at the discharge end of the residue storage bin (201); and the discharge end of the crusher (203) is connected to the circulating fluidized bed incinerator (2) via a first feeder (204); and a second feeder (205) is provided between the auxiliary fuel storage bin (202) and the circulating fluidized bed incinerator (2).

6. The waste incineration power generation system based on pyrolysis gasification process according to any one of claims 1 to 5, characterized in that: An air distribution plate (206) and an air chamber (207) are provided at the lower portion of the circulating fluidized bed incinerator (2). The air chamber (207) is connected to the air preheater (7) via a pipeline. The preheated primary air is transported to the air chamber (207) and then enters the circulating fluidized bed incinerator (2) through the air distribution plate (206).

7. The waste incineration power generation system based on pyrolysis and gasification process according to any one of claims 1 to 5, characterized in that: The high-temperature flue gas outlet at the upper portion of the circulating fluidized bed incinerator (2) is connected to a cyclone separator (208), the gas outlet of the cyclone separator (208) is respectively connected to the pyrolysis gasifier (1) and the superheater (5), the solid outlet of the cyclone separator (208) is connected to a return device (209), and the return device (209) is connected to the circulating fluidized bed incinerator (2) so that the unburned particles separated by the cyclone separator (208) are returned to the circulating fluidized bed incinerator (2) by the return device (209) for continued incineration.

8. The waste incineration power generation system based on pyrolysis and gasification process according to any one of claims 3 to 5, characterized in that: A gas mixer (302) with a dust removal function is provided between the pyrolysis gasification gas outlet (108) and the gas combustion chamber (3). The combustible gas generated by the pyrolysis gasification furnace (1) and the biogas in the biogas storage tank (301) are evenly mixed in the gas mixer (302) and then enter the gas combustion chamber (3), where they are mixed with the air entering through the air inlet pipe (303) and ignited and burned by the burner (304) in the gas combustion chamber (3).

9. The waste incineration power generation system based on pyrolysis and gasification process according to claim 8 is characterized in that: The top of the gas combustion chamber (3) is provided with an injection device (305), and the injection device (305) is used to spray the leachate concentrate into the gas combustion chamber (3) for coordinated incineration treatment.

10. The waste incineration power generation system based on pyrolysis gasification process according to any one of claims 3 to 5, characterized in that: The grate (103) includes a high-temperature flue gas inlet (1031) arranged in a horizontal direction and a compressed air inlet (1032) arranged in a vertical direction; the high-temperature flue gas generated by the circulating fluidized bed incinerator (2) enters the pyrolysis gasification furnace (1) through the high-temperature flue gas inlet (1031), provides the heat required for the pyrolysis and gasification of garbage, and disturbs the garbage; compressed air enters the pyrolysis gasification furnace (1) through the compressed air inlet (1032) to push the garbage forward; and the interaction between the two gases can flip the garbage and enhance heat and mass transfer.

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