CN105907428B

CN105907428B - Device for preparing gas by grading, fast pyrolysis and gasification of small and medium-sized domestic garbage

Info

Publication number: CN105907428B
Application number: CN201610280033.5A
Authority: CN
Inventors: 田原宇; 乔英云; 田斌; 郝俊辉; 张华伟
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-04-29
Filing date: 2016-04-29
Publication date: 2020-01-03
Anticipated expiration: 2036-04-29
Also published as: CN105907428A

Abstract

The invention provides a device for preparing fuel gas by grading, fast pyrolysis and gasification of small and medium-sized domestic garbage, which comprises a deferrization crusher, a lifting pipe, a circulating fluidized bed, a gas distributor, an ash discharge pipe, a gas inlet pipe, a feed inlet, a first-stage gas-solid separator, a coarse ash circulating pipe, a material returning device, a second-stage gas-solid separator, a fine ash circulating pipe, an entrained flow bed, a fuel gas outlet, an air heat exchanger and the like; the front end of the circulating fluidized bed is sequentially provided with a deferrization crusher and a lifting pipe, the bottom of the circulating fluidized bed is provided with a gas distributor and an ash discharge pipe, the position which is 1000-plus-2000 mm away from the bottom is provided with an entrained flow bed, the position which is 500-plus-3000 mm away from the entrained flow bed is provided with an oil gas feed inlet, and the top is provided with a secondary gas-solid separator; the coarse particle ash circulating pipe of the first stage gas-solid separator is introduced into the bottom of the circulating fluidized bed, the fine particle ash circulating pipe of the second stage gas-solid separator is connected with the entrained flow bed through a material returning device, and the gas outlet is connected with the gas outlet through an air heat exchanger.

Description

Device for preparing gas by grading, fast pyrolysis and gasification of small and medium-sized domestic garbage

1. Field of the invention

The invention provides a device for preparing fuel gas by grading, fast pyrolysis and gasification of small and medium-sized domestic garbage, belonging to the field of environmental protection equipment.

2. Background of the invention

At present, urban garbage in various countries of the world is treated mainly by classified recovery, landfill, composting and incineration, cracking and gasification. The landfill treatment needs a large amount of land. Meanwhile, harmful ingredients in the garbage can cause serious pollution to the atmosphere, soil and water sources, so that the ecological environment is destroyed, and the human health is seriously harmed; the compost treatment is used for sorting and classifying the garbage, and the organic content of the garbage is required to be higher. Moreover, the composting treatment cannot be reduced, and a large amount of land still needs to be occupied.

The essence of incineration is to oxidize the organic waste into inert gases and inorganic incombustibles at high temperature and under sufficient oxygen supply to form a stable solid residue. Firstly, the garbage is put into an incinerator for combustion, heat energy is released, and then waste heat is recovered to supply heat or generate electricity. The flue gas is discharged after being purified, and a small amount of residual residues are discharged, buried or used for other purposes. The method has the advantages of rapid volume reduction capability, thorough high-temperature harmless treatment, small occupied area, heat energy recovery, inevitable generation of dioxin which is a highly toxic substance and is difficult to decompose in the chlorine-containing organic matters in the garbage due to the existence of oxygen, and bottleneck for restricting the application of garbage incineration.

The household garbage cracking is a newly developed technology in recent years, the utilization rate of garbage resources is high, dioxin is not generated, but oil products are complex in components and difficult to utilize, phenol water which is difficult to treat is generated, and in addition, the large-scale production is difficult to realize mainly by using a fixed bed technology; the domestic garbage gasification has high utilization rate of garbage resources, generates less dioxin, but has low gas heat value, needs to remove tar and has high utilization difficulty, and the large-scale production is difficult to realize mainly by a fixed bed technology at present.

The household garbage coupling fluidized bed graded pyrolysis gasifier (CN201220525246) solves the problem of flying ash of fluidized bed gasification, eliminates dioxin and peculiar smell from the source, reasonably utilizes heat energy to obtain fuel gas with high methane content, does not contain tar and does not produce phenol water, but has low drying efficiency of a drum dryer and high water content of garbage, so that the temperature and the heating rate of the hydro-sleeve type quick pyrolysis of the garbage are influenced, and the heat value of the fuel gas is reduced. In addition, the defects that water vapor generated by drying of the sleeve type roller dryer is difficult to carry to the bottom of the fluidized bed to be used as a gasifying agent, the sleeve of the synthetic gas is difficult to move and seal at high temperature and low speed, the amount of leachate is large, and the like are difficult to treat.

In the face of the phenomenon of waste enclosure, the development of clean energy waste treatment technology and equipment which can eliminate secondary pollution of dioxin, fly ash and peculiar smell and can reasonably utilize leachate and waste resource energy is urgently needed.

3. Summary of the invention

The invention aims to overcome the defects of the existing garbage pyrolysis gasification technology and provide a device for preparing fuel gas by grading, fast pyrolysis and gasification of small and medium-sized domestic garbage, which solves the problem of fly ash of fluidized bed gasification, eliminates dioxin and peculiar smell from the source, reasonably utilizes leachate and heat energy, obtains fuel gas with high methane content, and simultaneously does not contain tar and generate phenol water.

The technical scheme of the invention is as follows:

the device for preparing the fuel gas by the grading, fast pyrolysis and gasification of the small and medium-sized domestic garbage comprises a deferrization crusher, a lifting pipe, a garbage gas-solid separator, a solid feeding port, a circulating fluidized bed, a gas distributor, an ash discharge pipe, a gas inlet pipe, a material return port, a first-stage gas-solid separator, a coarse ash circulating pipe, a material return device, a second-stage gas-solid separator, a fine ash circulating pipe, an entrained flow bed, a fuel gas outlet, an air heat exchanger and the like; the front end of the circulating fluidized bed is sequentially provided with a deferrization pulverizer and a lifting pipe, the deferrization pulverizer is connected with the lifting pipe through a heat exchange air pipeline, and the top of the lifting pipe is provided with a garbage gas-solid separator; the gas outlet of the garbage gas-solid separator is connected with a gas distributor at the bottom of the circulating fluidized bed, and the solid outlet is connected with a solid feed inlet in the middle of the circulating fluidized bed through a feeder; the bottom of the circulating fluidized bed is provided with a gas distributor and an ash discharge pipe, a material return port is arranged at a position which is 1000mm away from the bottom, an entrained flow bed is arranged at a position which is 3000mm away from the material return port and is upward 300 mm away from the material return port, a solid feed port is arranged at a position which is 3000mm away from the entrained flow bed and is upward 500 mm away from the entrained flow bed, and the top of the circulating fluidized bed is provided with a secondary gas-solid separator; the coarse ash circulating pipe of the first stage gas-solid separator is connected with a material returning port at the bottom of the circulating fluidized bed through a material returning device, the fine ash circulating pipe of the second stage gas-solid separator is connected with the entrained flow bed through the material returning device, and the gas outlet of the second stage gas-solid separator is connected with the gas outlet through an air heat exchanger.

The circulating fluidized bed is formed by combining a turbulent fluidized bed at the lower part, a reactor carried at the upper part and an entrained flow bed communicated with the reactor in a Y shape at the lower part, the equivalent diameter of the turbulent fluidized bed is larger, the equivalent diameter of the reactor carried is smaller, and the diameter ratio is 2-3: 1; carry the reactor both can be the straight tube reactor that the equivalent diameter is homogeneous, also can be formed by the diameter through big small-end pipe fitting connection for the big small-end straight tube of different equivalent diameter multiples, the diameter ratio of big small-end straight tube is 1.2 ~ 2: 1; the equivalent diameter of the entrained flow bed is only 10-50% of the equivalent diameter of the turbulent fluidized bed.

The reaction temperature of the turbulent fluidized bed is 800-1200 ℃, the reaction temperature of the entrained flow bed is 1200-1600 ℃, the reaction temperature of the solid feed inlet of the entrained flow reactor is 700-1000 ℃, the reaction temperature of the upper part of the entrained flow reactor is 600-900 ℃, and the reaction temperature of the outlet of the heat exchange bin is 30-80 ℃.

The present invention will be described in detail with reference to examples.

4. Description of the drawings

FIG. 1 is a schematic structural diagram of a device for preparing fuel gas by classified rapid pyrolysis and gasification of small household garbage.

The drawings of the drawings are set forth below:

1. the system comprises a circulating fluidized bed 2, a gas distributor 3, a gas inlet pipe 4, a feeder 5, a first-stage gas-solid separator 6, a material returning device 7, a second-stage gas-solid separator 8, an entrained-flow bed 9, a gas outlet 10, a deferrization pulverizer 11, a lifting pipe 12, a turbulent fluidized bed 13, a entrained-bed reactor 14, a garbage gas-solid separator 15, an ash discharge pipe 16, a material returning port 17, a coarse ash circulating pipe 18, a fine ash circulating pipe 19, an air heat exchanger 20, a heat exchange air pipeline 21, a solid feed inlet

The process features of the present invention are described in detail below with reference to the accompanying drawings and examples.

5. Detailed description of the preferred embodiments

The device for preparing the fuel gas by the classified rapid pyrolysis and gasification of the small and medium-sized domestic garbage comprises a deferrization crusher (10), a lifting pipe (11), a garbage gas-solid separator (14), a feeder (4), a solid feeding hole (21), a circulating fluidized bed (1), a gas distributor (2), an ash discharge pipe (15), a gas inlet pipe (3), a material return hole (16), a first-stage gas-solid separator (5), a coarse ash circulating pipe (17), a material return device (6), a second-stage gas-solid separator (7), a fine ash circulating pipe (18), an entrained flow bed (8), a fuel gas outlet (9), an air heat exchanger (19), a heat exchange air pipeline (23) and the like; a deferrization crusher (10) and a lifting pipe (11) are sequentially arranged at the front end of the circulating fluidized bed (1), the deferrization crusher (10) is connected with the lifting pipe (11) through a heat exchange air pipeline (23), and a garbage gas-solid separator (14) is arranged at the top of the lifting pipe (11); a gas outlet of the garbage gas-solid separator (14) is connected with a gas distributor (2) at the bottom of the circulating fluidized bed (1), and a solid outlet is connected with a solid feeding hole (21) at the bottom of the circulating fluidized bed (1) through a feeder (4); the bottom of the circulating fluidized bed (1) is provided with a gas distributor (2) and an ash discharge pipe (15), a return port (16) is arranged at a position which is 300-1000mm away from the bottom, an entrained flow bed (8) is arranged at a position which is 300-3000mm away from the return port (16), a solid feed port (21) is arranged at a position which is 500-3000mm away from the entrained flow bed (8), and the top of the circulating fluidized bed is provided with a secondary gas-solid separator; a coarse ash circulating pipe (17) of the first-stage gas-solid separator (1) is connected with a material returning port (16) at the bottom of the circulating fluidized bed (1) through a material returning device (6), a fine ash circulating pipe (18) of the second-stage gas-solid separator (7) is connected with an entrained flow bed (8) through the material returning device (6), and a gas outlet of the second-stage gas-solid separator (7) is connected with a gas outlet (9) through an air heat exchanger (19).

The circulating fluidized bed (1) is formed by combining a turbulent fluidized bed (12) at the lower part, a carrying reactor (13) at the upper part and an entrained flow bed (8) communicated with the Y-shaped lower part of the carrying reactor (13), the turbulent fluidized bed (12) has larger equivalent diameter, the carrying reactor (13) has smaller equivalent diameter, and the diameter ratio is 2-3: 1; carry reactor (13) both can be the straight tube reactor that the equivalent diameter is homogeneous, also can be formed by the big or small straight tube of diameter for different equivalent diameter multiples through big or small head pipe connection, the diameter ratio of big or small straight tube is 1.2 ~ 2: 1; the equivalent diameter of the entrained flow bed (8) is only 10% -50% of the equivalent diameter of the turbulent fluidized bed (12).

The reaction temperature of the turbulent fluidized bed (12) is 800-.

When the operation is carried out in a specific way,

the household garbage is subjected to deferrization and crushing by a deferrization crusher (10), then, garbage particles of 0-6 mm are lifted and dried by air subjected to gas heat exchange through a lifting pipe (11), separated by a garbage gas-solid separator (14) at the top of the lifting pipe, the air containing peculiar smell steam after heat exchange returns to the bottom of a circulating fluidized bed (1) to serve as a gasifying agent, the hot garbage particles enter the middle lower part of the circulating fluidized bed (1) through a feeder (4) to be mixed with gasified gas and circulating ash, subjected to a hydrocracking reaction at the temperature of 800-; the top of the circulating fluidized bed (1) is subjected to gas-solid separation, the high-temperature large and medium particle carbon-containing hot ash separated by the first stage gas-solid separator (5) returns to the bottom of the circulating fluidized bed (1) through a material returning device (6), and is subjected to gasification reaction with air containing peculiar smell steam at 800-1100 ℃ after heat exchange, and the generated gasified gas and the circulating ash flow upwards together to form material circulation; the high-temperature fine semicoke separated by the second-stage gas-solid separator (7) is sent to an entrained flow bed (8) communicated with the middle lower part of the circulating fluidized bed (1) in a Y shape, enters the entrained flow bed (8) to react at 1200-1600 ℃ along a tangent line under the carrying of water vapor and an oxidant, and the generated high-temperature gas and liquid ash slag flow obliquely downwards in a cyclone manner to flow out of the entrained flow bed (8), and the high-temperature gas rises upwards to enter the middle lower part of the circulating fluidized bed (1) to provide heat for the hydro-pyrolysis of the tar in the fluidized bed; the liquid ash flows downwards to a circulating ash layer of the circulating fluidized bed (1), is solidified into solid ash through heat exchange, and participates in circulation or ash discharge along with the solid material of the circulating fluidized bed (1); the synthesis gas separated by the second-stage gas-solid separator (7) is used as a fuel gas product for external supply, thereby solving the problem of fly ash in fluidized bed gasification, eliminating dioxin, leachate and peculiar smell from the source and obtaining fuel gas with high methane content.

The common fluidized bed is usually of a structure with a small lower part and a large upper part, the upper part is large, the gas velocity is low, and particles which are slightly larger are difficult to circulate, so that the heat carried by the middle upper part of the fluidized bed is insufficient, the heat requirement of tar cracking cannot be met, and tar and phenol water pollution is difficult to eliminate. As the activity of the fly ash is low at 800-1100 ℃, the reaction in the fluidized bed is difficult to completely react, and the fly ash has to be discharged outside, thereby causing the fly ash pollution of the household garbage fluidized bed treatment. If the fly ash is melted and gasified in the entrained flow bed (8) at 1200-1600 ℃, the fly ash is melted, solidified and pollution-free, but the liquid slag discharge needs rapid cooling, the energy loss is large, and the ash discharge process is complex. In addition, the circulating fluidized bed (1) with a structure of big bottom and small top and the turbulent fluidized bed (12) at the bottom can prolong the retention time of the semicoke and increase the internal reflux, thereby ensuring that the high conversion efficiency is achieved when the heat carrier and the high-temperature coarse semicoke are gasified; the upper carrying bed reactor (13) reduces the diameter, increases the gas flow rate, can improve the circulation quantity and the particle size distribution range of a heat carrier, provides a sufficient heat source for the hydro-pyrolysis and the re-cracking of the garbage, thoroughly eliminates the tar, avoids the pollution of phenol water, and improves the methane content and the heat value of fuel gas; the entrained flow bed (8) with the Y-shaped communication at the middle and lower parts can melt and gasify the fly ash and the fine semicoke at 1200-1600 ℃, so that the fly ash is melted, solidified and pollution-eliminated, and simultaneously the high-temperature heat energy of the entrained flow bed is fully utilized. The specific structural combination is the optimal combination, the device for preparing the fuel gas by the graded rapid pyrolysis and gasification of the small and medium-sized domestic garbage can reasonably utilize heat energy and leachate, eliminate tar in the gasification process, solve the problem of fly ash in fluidized bed gasification, eliminate dioxin treated by the domestic garbage from the source, obtain the fuel gas with high methane content, and simultaneously, the fuel gas does not contain tar and does not produce phenol water; low oxygen consumption, high gasification efficiency, high gasification strength, small equipment volume, low steel consumption, greatly reduced fixed investment and simple ash discharge process.

Claims

1. The device for preparing the fuel gas by the graded fast pyrolysis and gasification of the small and medium-sized domestic garbage comprises a deferrization pulverizer, a lifting pipe, a garbage gas-solid separator, a solid feeding port, a circulating fluidized bed, a gas distributor, an ash discharge pipe, a gas inlet pipe, a material return port, a first-stage gas-solid separator, a coarse ash circulating pipe, a material return device, a second-stage gas-solid separator, a fine ash circulating pipe, a fuel gas outlet and an air heat exchanger, and is technically characterized in that the deferrization pulverizer and the lifting pipe are sequentially arranged at the front end of the circulating fluidized bed, the deferrization pulverizer is connected with the lifting pipe through a heat exchange air pipeline, and the garbage; the gas outlet of the garbage gas-solid separator is connected with a gas distributor at the bottom of the circulating fluidized bed, and the solid outlet is connected with a solid feed inlet in the middle of the circulating fluidized bed through a feeder; the bottom of the circulating fluidized bed is provided with a gas distributor and an ash discharge pipe, a material return port is arranged at a position which is 1000mm away from the bottom, an entrained flow bed is arranged at a position which is 3000mm away from the material return port and is upward 300 mm away from the material return port, a solid feed port is arranged at a position which is 3000mm away from the entrained flow bed and is upward 500 mm away from the entrained flow bed, and the top of the circulating fluidized bed is provided with a secondary gas-solid separator; the coarse ash circulating pipe of the first stage gas-solid separator is connected with a material returning port at the bottom of the circulating fluidized bed through a material returning device, the fine ash circulating pipe of the second stage gas-solid separator is connected with the entrained flow bed through the material returning device, and the gas outlet of the second stage gas-solid separator is connected with the gas outlet through an air heat exchanger.

2. The device for preparing the fuel gas by the staged fast pyrolysis and gasification of the small and medium-sized domestic garbage according to claim 1, wherein the circulating fluidized bed is formed by combining a turbulent fluidized bed at the lower part, a carrying reactor at the upper part and an entrained flow bed communicated with the carrying reactor in a Y shape at the lower part, the turbulent fluidized bed has a larger equivalent diameter and a smaller equivalent diameter of the carrying reactor, and the diameter ratio is 2-3: 1; carry the reactor both can be the straight tube reactor that the equivalent diameter is homogeneous, also can be formed by the diameter through big small-end pipe fitting connection for the big small-end straight tube of different equivalent diameter multiples, the diameter ratio of big small-end straight tube is 1.2 ~ 2: 1; the equivalent diameter of the entrained flow bed is only 10-50% of the equivalent diameter of the turbulent fluidized bed.

3. The device for preparing fuel gas by fractional fast pyrolysis and gasification of middle and small sized domestic garbage according to claim 1, wherein the turbulent fluidized bed has a reaction temperature of 800-.