CN117091138B

CN117091138B - Household garbage thermal conversion-thermal separation coupling process and device

Info

Publication number: CN117091138B
Application number: CN202311337358.9A
Authority: CN
Inventors: 王建军; 王泽�; 王红伟; 孙子强; 房贤卓; 王瑞; 张靖旋
Original assignee: Zhongpeng Future Co ltd; Institute of Process Engineering of CAS
Current assignee: Zhongpeng Future Co ltd; Institute of Process Engineering of CAS
Priority date: 2023-10-17
Filing date: 2023-10-17
Publication date: 2024-03-01
Anticipated expiration: 2043-10-17
Also published as: CN117091138A

Abstract

The invention relates to a household garbage thermal conversion-thermal separation coupling process and a device, wherein the thermal conversion comprises two modes of baking and pyrolysis, and the thermal conversion-thermal separation coupling process comprises four steps of processes of a drying step, a thermal conversion crushing step, a primary fluidization thermal conversion screening step and a secondary fluidization thermal conversion screening step. The invention can realize the simultaneous thermal conversion, crushing and separation treatment of the household garbage materials, the coupling of the thermal conversion and the crushing separation processes are cooperated, the mutual reinforcement can obviously improve the thermal conversion reaction rate and conversion efficiency of the household garbage, and various sorting products including metal and nonmetal inorganic matters except the heat conversion upgrading fuel can be recovered at the same time, especially the obtained upgrading fuel has powdery state, is suitable for being used as a gasification raw material of a powder boiler and/or an entrained flow bed, and has outstanding recycling high-value utilization value.

Description

Household garbage thermal conversion-thermal separation coupling process and device

Technical Field

The invention relates to the field of household garbage incineration and resource utilization, wherein household garbage comprises primary municipal household garbage and rural household garbage, and in particular relates to a household garbage thermal conversion-thermal separation coupling process and device.

Background

The household garbage has complex components and comprises various components such as kitchen garbage, paper, plastic products, glass products, metal and the like. At present, domestic garbage is mainly treated by landfill, anaerobic fermentation, incineration and other modes (such as Chinese patent CN219036642U, CN 102897972A), however, land resources available for landfill are limited, anaerobic fermentation period is long, efficiency is low, and direct incineration can cause secondary pollution to the environment and generate a large amount of greenhouse gases. Meanwhile, thermochemical conversion and high-value utilization technologies including gasification, baking, pyrolysis and hydrothermal carbonization are receiving attention due to the great demand of energy.

However, the original garbage has the disadvantages of high water content, poor uniformity, low energy density and the like, so that the original garbage is not suitable for direct incineration or direct gasification, the original garbage can be incinerated or gasified after being subjected to pretreatment such as drying, crushing and the like, but the original garbage has more soft sticky components and poor crushability and grindability, and the pretreatment efficiency is extremely low, so that the implementation effect and the application efficiency of the garbage incineration or gasification technology are seriously limited, and therefore, the original garbage pretreatment technology is required to be developed, so that the original garbage pretreatment technology is suitable for being used as a combustion and gasification raw material, or the thermal conversion upgrading technology capable of directly carrying out conversion and crushing without crushing pretreatment.

The baking and pyrolysis are fuel thermal conversion upgrading technology under inert atmosphere, can obviously improve the fuel characteristics of household garbage, such as energy density, grindability, uniformity and the like, and can effectively improve the combustion stability of fuel or improve the refrigerant gas efficiency (CGE) and the quality of synthesis gas of gasification reaction in subsequent combustion or gasification reaction.

Despite the advantages of torrefaction or pyrolysis conversion, there are not so many practical applications that currently combine torrefaction or pyrolysis technology with household garbage incineration or gasification processes. The reason for this is that existing torrefaction and pyrolysis technologies still face several major problems. Firstly, compared with gasification and combustion, the operation temperature of baking or pyrolysis treatment is lower, so that the surface temperature of the material is raised slowly, the volume of the uncrushed material is larger, the internal temperature is raised more slowly, especially the converted surface product is attached to the outer side of the material, meanwhile, the heat conduction rate of the surface product is lower due to the porous product layer structure, the heat transfer to the inside of the material is further limited, the internal temperature rise of the material is not facilitated, the thermal conversion effect is poor, the production efficiency is lower, and the operation time is longer. Second, the composition and volume distribution of the waste material are very uneven, and at a certain temperature, a situation may occur in which small-particle easily-reacted materials have been completely converted, while large-volume difficultly-reacted materials have not been sufficiently reacted, resulting in low baking or pyrolysis efficiency.

In view of the above, the invention provides a technical scheme capable of carrying out thermal conversion, crushing and separation simultaneously, namely coupling and cooperation of the thermal conversion and crushing separation processes, and mutual reinforcement, wherein porous product shells formed on the surfaces of materials can be rapidly stripped in the thermal conversion and crushing processes, the interiors of the materials are exposed to the thermal conversion temperature, the thermal conversion reaction rate and conversion efficiency of household garbage are obviously improved, various sorting products except the thermal conversion and quality improvement fuel can be simultaneously recovered, and particularly the obtained quality improvement fuel has powdery state, is suitable for being used as a gasification raw material of a powder boiler and/or an entrained flow bed, and has outstanding recycling high-value utilization value.

Disclosure of Invention

In order to achieve the above purpose, the invention adopts the following technical scheme:

the contents in the present invention refer to mass contents unless otherwise specified; the operating temperature in the present invention refers to the temperature at which the solid material is discharged from a device.

The household garbage thermal conversion-thermal separation coupling process comprises a drying step, a thermal conversion crushing step, a primary fluidization thermal conversion screening step and a secondary fluidization thermal conversion screening step which are sequentially executed, wherein the drying step refers to drying treatment of the household garbage through a drying device so as to remove a large amount of water contained in the household garbage, and the obtained dry household garbage enters a downstream thermal conversion crushing device; the thermal conversion crushing step performs the thermal conversion treatment while crushing the dried household garbage.

The drying device can be a rotary drum drying device, a spiral conveying drying device, a crawler-type drying device and other conventional drying devices in the field; the heat preservation conveying is adopted between the drying device and the heat conversion crushing device at the downstream side of the drying device, so that heat loss in the conveying process between the two steps is reduced.

Preferably, the operation temperature of the drying step is 120-180 ℃;

preferably, the water content of the material treated by the drying step is not more than 5%;

preferably, the heat required by the drying step is provided by a first gas heat carrier, the first gas heat carrier at least comprises a first sweeping gas part, the first sweeping gas and the material to be dried are in heat and mass transfer in a direct contact mode, the heat required by the drying is provided for the material to be dried, and water vapor evaporated from the surface of the material is entrained; the gas phase stream produced after purging is passed through a combustion or flue gas cleaning system.

The thermal conversion crushing step is performed at a temperature not lower than the drying treatment temperature.

The limitation of the treatment temperature of the thermal conversion crushing step is important because part of the components in the household garbage, such as kitchen garbage, plastic products and the like, show soft adhesion at the drying temperature, so that the crushing process is not facilitated (problems of sticking of cutters, re-sticking of materials and the like can occur). In the prior art, the materials are cooled after the drying treatment to reduce the viscosity of the materials and then the crushing process is carried out. However, in the treatment step after crushing the materials, the materials still need to be heated for heat conversion operation, and obviously, the cooling before crushing and the reheating process after crushing cause a great deal of heat loss.

In order to avoid the heat loss of the part, the invention does not cool the materials before the crushing step, and simultaneously introduces heat conversion treatment in the crushing process to reduce the viscosity of the household garbage materials at the temperature, thereby overcoming the technical obstacle which is unfavorable for crushing at the drying temperature.

Specifically, a second gas heat carrier is provided for the materials to be crushed in the thermal conversion crushing step so as to realize the thermal conversion treatment while crushing.

The second gas heat carrier provides the material in the crushing stage with the temperature required by thermal conversion, so that the soft-sticky section can be rapidly decomposed and dehydrated and/or thermally converted to form a brittle product shell at the new soft-sticky section formed by crushing even if the material is crushed and forms a new soft-sticky section, and the crushing problem of the soft-sticky material is effectively solved.

The second gaseous heat carrier comprises at least a second sweep gas flowing over the surface of the material, the second sweep gas being capable of entraining moisture generated by decomposition of the material surface and fine fuel particles that are exfoliated from the material surface by the disruption.

Specifically, the thermal conversion crushing step is to perform thermal conversion and crushing treatment on materials from a drying device through crushing equipment under heating conditions, fine powder with smaller particle size and density in continuously peeled thermal conversion products enters a gas-solid separation device along with second purge gas, so that gas-phase products and powdery thermal conversion upgraded fuel are respectively obtained, and larger particles and blocks which are not fully converted enter a downstream primary fluidization thermal conversion screening step.

Preferably, the thermal conversion crushing step adopts a double-layer rotary drum device with inner and outer heat exchange simultaneously, wherein the inner drum is used as a crushing channel, a mechanical crushing part is arranged in the inner drum, two ends of the inner drum are respectively connected with a material outlet of a drying device and a material inlet of a downstream primary fluidized bed, and meanwhile, two ends of the inner drum are respectively provided with a second purge gas inlet and a second purge gas outlet, and the second purge gas is in concurrent contact with the material to be crushed in the inner drum; the second purge gas outlet is connected with a gas-solid separation device and is used for separating fine powder entrained in the second purge gas from the gas stream so as to obtain heat conversion upgraded fuel particles; and two ends of the outer cylinder are provided with second gas heat carrier inlets and outlets for introducing second gas heat carriers except the second purge gas into the interlayer of the inner cylinder and the outer cylinder.

Preferably, the action forms of the mechanical breaking member include shearing (metal cutters moving in reverse) and/or hammering (metal chain balls falling continuously);

preferably, the operating temperature of the thermal conversion crushing device is 180-250 ℃.

After the heat conversion crushing step, the residual granular materials are conveyed to a primary fluidized bed for primary fluidization heat conversion screening treatment.

Specifically, the primary fluidization heat conversion screening treatment is performed by supplying a third gas heat carrier to the lower part of the primary fluidized bed; inorganic particles generated by the thermal conversion crushing unit form grinding machine materials in the primary fluidized bed, wherein the density of the grinding machine materials is smaller than that of metal aluminum but larger than that of fine organic matters and fine fuel particles in household garbage; the grinding bed material is in a boiling and fluidization state in the fluidized bed by adjusting the supply amount and the gas speed of the third gas heat carrier, and the fluidization effect of the uneven particles is improved by mechanical vibration; the powdery thermal conversion upgraded fuel enters a gas phase along with the fluidizing gas and goes to a gas-solid separation unit; heavy components such as metal and part of large-particle organic matters are in a non-fluidized state and are deposited at the bottom of a bed to form a bottom material, and the bottom material enters a screw airflow bidirectional conveying mechanism under the action of mechanical vibration; the light materials (the light materials refer to light materials relative to metal) in the bottom materials are reversely blown back to the gas phase space of the fluidized bed in the screw gas flow bidirectional conveying mechanism, wherein large-particle organic matters which are not fully reacted are settled again and fully contacted with a gas heat carrier and a grinding bed material, and are continuously converted and crushed to obtain powdery heat conversion upgrading fuel; heavy materials in the bottom materials which are not blown back to the fluidized bed are discharged out of the system through a screw airflow bidirectional conveying mechanism, and the metal content of the discharged bottom materials is not less than 80%; the third gaseous heat carrier comprises flue gas having a pyrolysis gas and/or gasification gas and/or oxygen content of not more than 0.5% by volume.

The third gas heat carrier serves as a fluidizing gas to boil and fluidize the particulate matter in the primary fluidized bed on the one hand and to provide the particulate matter with a temperature required for thermal conversion on the other hand.

The supply amount, the gas speed and the vibration intensity of the third gas heat carrier are adjusted so that the grinding bed material is in a boiling and fluidization state in the fluidized bed.

The granular material from the thermal conversion crushing step contains organic particles such as kitchen, paper scraps, plastics and the like, and inorganic particles such as fine sand, soil, glass and the like also comprise metal blocks such as iron, copper, aluminum and the like. Wherein the density of the organic particles is smaller than that of the grinding bed material, and the density of the metal blocks is larger than that of the grinding bed material. Therefore, under the fluidization air speed and vibration conditions set by the invention, the grinding bed material taking inorganic particles as main components is in a boiling fluidization state in the primary fluidized bed; the organic component having a density less than that of the grinding bed material is heated by the third gaseous heat carrier, thereby undergoing thermal conversion at the surface thereof and forming a product shell, while also being subjected to continuous friction of the inorganic particles in a boiling state, which causes the product shell at the surface of the small organic particles to peel off and the new thermal conversion surface to be exposed to the third gaseous heat carrier, thereby accelerating the thermal conversion process. Although the larger-sized organic particles are difficult to fluidize in the early stage, the larger-sized organic particles gradually change into fluidizable small-sized organic particles as the surface thermal conversion reaction proceeds and the product shell is continuously peeled off due to friction with the abrasive bed material. On the other hand, since the density of the metal block is greater than that of the ground bed material, the metal block cannot be fluidized under the fluidization air velocity set by the invention, so that the bed material is enriched and formed at the bottom of the bed layer.

Preferably, in order to solve the problem of continuous accumulation of materials in the fluidized bed, the invention is provided with a screw airflow bidirectional conveying mechanism at the bottom of the primary fluidized bed for discharging the bottom materials taking metal blocks as main components, and a first overflow outlet is arranged at the middle upper part of the primary fluidized bed for discharging organic matters and inorganic matters particles which are not fully converted in a fluidized state.

Preferably, in order to improve the air flow uniform distribution characteristic in the fluidized bed and prevent large particle materials and metal blocks from blocking the air distribution channel of the fluidized air, the invention adopts the air pipelines which are crossed horizontally and longitudinally as air distribution plates and is arranged on a horizontal plane higher than the height of the bed charge, and the air caps are arranged at the crossing points of the air pipelines; large particle materials and metal blocks fall into a bottom material accumulation area with an inclined bottom surface at the lower part of the air distribution plate through a pipeline gap; the non-fluidized bed charge moves downwards along the inclined surface under the action of mechanical vibration and enters the screw airflow bidirectional conveying mechanism; the screw airflow bidirectional conveying mechanism comprises a horizontal conveying screw and a gas distributor arranged at the lower part of the horizontal conveying screw; the light and small materials in the screw are blown away from the screw by the air flow blown in from the lower part of the screw and returned to the upper space of the fluidized bed, and the large-particle organic components which are not fully converted in the returned materials are settled again and fully contacted with the gas heat carrier and the grinding bed material, so that collision friction with the bed material promotes the formation, stripping and reconversion of the product shells on the surfaces of the organic components, and the powdery thermal conversion upgraded fuel is obtained; heavy materials which are not blown back to the fluidized bed in the screw airflow bidirectional conveying mechanism are discharged out of the system under the pushing action of the screw, and the metal content of the discharged bottom materials is not less than 80%; the third gaseous heat carrier comprises flue gas having a pyrolysis gas and/or gasification gas and/or oxygen content of not more than 0.5% by volume.

Wherein, the particles blown off from the screw airflow bidirectional conveying mechanism return to the upper part of the gas phase space of the primary fluidized bed through an independent flowing return path; specifically, a baffle plate is arranged above the screw airflow bidirectional conveying mechanism, and a return path communicated with the upper part of a gas phase space of the first fluidized bed is constructed in the first fluidized bed; the bottom of the partition plate is higher than the sloping plate to form a passage for the bottom material to enter the screw airflow bidirectional conveying mechanism.

Preferably, the operating temperature of the primary fluidized heat conversion screening device is 280-310 ℃;

inorganic particles discharged from an overflow port of the primary fluidized bed comprise coarse sand, fine sand, glass slag and the like, and are mixed with more incompletely converted organic particles and partial product shell fragments. And (3) continuously introducing the part of materials into a secondary fluidized bed to carry out secondary fluidization heat conversion screening treatment.

In the secondary fluidized bed, a fourth gas heat carrier is introduced from the bottom of the secondary fluidized bed to serve as fluidizing gas; all materials are positioned at the upper part of the air distribution plate, the materials in the bed are in a boiling and fluidization state by adjusting the supply amount and the air speed of the fourth air heat carrier, and the fluidization effect of the uneven particles is improved by mechanical vibration; in the boiling process, the surfaces of the organic particles continue to undergo thermal conversion reaction and rub against fluidized inorganic particles, and peeled product shell scraps enter a gas phase along with a gas heat carrier, namely powdery thermal conversion upgraded fuel is discharged from the top of a secondary fluidized bed and goes to a gas-solid separation unit; the two-stage fluidized bed is provided with two material overflow outlets in the vertical direction respectively, heavier materials are discharged from the lower overflow outlet, and light materials are discharged from the upper overflow outlet; preferably, the overflow discharge of the lower part of the secondary fluidized bed mainly comprises glass slag and coarse sand grains, wherein the content of non-metal inorganic matters is not less than 95%; preferably, the overflow discharge of the upper part of the secondary fluidized bed is mainly fine sand particles, wherein the content of non-metal inorganic matters is not less than 98%; the fourth gaseous heat carrier comprises flue gas having a pyrolysis gas and/or gasification gas and/or oxygen content of not more than 0.5% by volume.

Preferably, the air distribution plate of the secondary fluidized bed is a horizontal metal plate with a hood uniformly embedded on the surface, and as large particle materials are obviously reduced, all bed materials are positioned at the upper part of the air distribution plate;

preferably, in order to improve the air flow uniform distribution characteristic in the fluidized bed and prevent large particles and accumulated metal blocks from blocking an air distribution channel of the fluidized air, the bottom of the secondary fluidized bed is provided with a vibrating device, and large particles which are difficult to fluidize are vibrated by the vibrating device to prevent the large particles from forming compact filling at the bottom of the fluidized bed so as to block the air distribution channel;

preferably, the operating temperature of the secondary fluidized heat conversion screening device is 310-600 ℃.

And outlets at the tops of the first-stage fluidized bed and the second-stage fluidized bed are respectively connected with a gas-solid separation device for separating product shell fragments and/or organic particles carried by the fluidizing gas from the gas flow to obtain the thermal conversion upgraded fuel.

Preferably, the oxygen content (all refer to volume content) of the first gas heat carrier in the invention is not more than 2%, the oxygen content of the second gas heat carrier is not more than 1%, and the oxygen content of the third and fourth gas heat carriers is not more than 0.5%. This oxygen content limitation can effectively avoid explosion risks during the thermal conversion process.

The invention also provides a device capable of executing the household garbage thermal conversion-thermal separation coupling process, which comprises a drying device, a thermal conversion crushing device, a primary fluidization thermal conversion screening device and a secondary fluidization thermal conversion screening device which are sequentially communicated; the devices are communicated by heat preservation so as to reduce heat loss in the conveying process.

The drying device can be a rotary drum drying device, a spiral conveying drying device, a crawler-type drying device and other conventional drying devices in the field.

The thermal conversion crushing device comprises an outer cylinder body and an inner cylinder body, wherein the bottom of the outer cylinder body is supported and fixed through a bracket; the inner cylinder body is rotatably sleeved in the outer cylinder body, the left end and the right end of the inner cylinder body are beyond the outer cylinder body and are rotationally sealed with the outer cylinder body, a jacket for circulating a second gas heat carrier is formed between the inner cylinder body and the outer cylinder body, and the two ends of the outer cylinder body are respectively provided with a second gas heat carrier air inlet and a second gas heat carrier air outlet; and an insulating layer is arranged on the outer side of the outer cylinder body.

The bottoms of the two ends of the inner cylinder body, which are beyond the outer cylinder body, are respectively provided with a pair of riding wheels, and the riding wheels are used for carrying out rolling support on the inner cylinder body; the outer surface of one end of the inner cylinder body is also provided with a gear, and the gear is matched with the driving device to drive the inner cylinder body to rotate.

The feeding end cap and the discharging end cap are respectively arranged at two ends of the inner cylinder body, and the feeding end cap and the discharging end cap are both sealed with the inner cylinder body in a rotating way and do not rotate along with the inner cylinder body. Wherein, the feeding end cap is provided with a material inlet which is used for introducing the dried household garbage into the inner cylinder body and a second purge gas inlet; the bottom of the discharging end cap is provided with a material outlet for discharging the materials subjected to thermal conversion crushing treatment, and the top of the discharging end cap is provided with a second purge gas outlet; the second purge gas outlet is connected with the gas-solid separation device.

The inner cylinder is internally provided with a crushing assembly, the crushing assembly comprises a bidirectional rotating shaft and a crushing part arranged on the bidirectional rotating shaft, and the crushing part comprises a shearing knife set and/or a rotary hammer set and/or a hammer set. The bidirectional rotating shaft consists of a plurality of sections of short shafts and reversing bevel gear sets, and the reversing bevel gear sets enable two adjacent short shafts to reversely rotate through three bevel gears which are meshed in sequence; crushing portions are provided on each stub shaft, respectively, so that the crushing portions on adjacent stub shafts are rotated reversely. One end of at least one short shaft extends out of the feeding end cap or the discharging end cap of the inner cylinder body and is in driving connection with the power component.

In order to further improve the crushing effect, a plurality of crushing parts are arranged on each short shaft, and the plurality of crushing parts on the same short shaft have two opposite rotation directions. Specifically, one part of the plurality of crushing parts on the same short shaft is fixedly connected with the short shaft through a fixed disc fixedly sleeved on the short shaft or directly connected with the short shaft, so that the first rotating direction is the same as the rotating shaft; the remaining crushing portion is rotatably connected to the stub shaft by a planetary gear assembly so as to have a second rotational direction opposite to the stub shaft. The planetary gear assembly comprises a sun gear fixedly sleeved with the short shaft, a transmission gear meshed with the sun gear, a gear ring meshed with the transmission gear and a frame (not shown in the figure) for fixing and/or supporting the sun gear, the transmission gear and the gear ring; the remaining crushing portion is fixed to the outer peripheral wall of the ring gear and thus has a second rotational direction opposite to the short axis.

Preferably, the crushing portions having opposite rotation directions on the same short axis are arranged at intervals from each other.

The inner cylinder body is obliquely arranged to convey the material to be crushed to the material outlet by utilizing the self gravity of the material. Or a conveying component is arranged in the inner cylinder body. The conveying part can be a conveying belt with two ends respectively fixed in the charging and discharging cap cover and positioned at the lower part of the inner cylinder body; or the conveying part can be a spiral blade fixed on the inner wall surface of the inner cylinder body, and when the inner cylinder body rotates, the spiral blade pushes the material to move towards the material outlet.

The primary fluidization heat conversion screening device comprises a primary fluidized bed, and a feed inlet of the primary fluidized bed is communicated with a material outlet of the heat conversion crushing device; the lower part of the primary fluidized bed is provided with a third gas heat carrier inlet communicated with a primary fluidized bed air distribution plate and a first discharge opening arranged at the bottom of one end of the screw airflow bidirectional conveying mechanism, the middle upper part of the primary fluidized bed is provided with a first overflow opening, and the top of the primary fluidized bed is provided with a third gas heat carrier outlet; the secondary fluidization heat conversion screening device comprises a secondary fluidized bed, and a feed inlet of the secondary fluidized bed is communicated with the first overflow port; the bottom of the secondary fluidized bed is provided with a fourth gas heat carrier inlet communicated with the air chamber.

Preferably, the primary and secondary fluidized beds in the present invention are vibratory fluidized beds (meaning fluidization with a vibratory assist gas rather than a substitute gas).

Specifically, as shown in fig. 5, the first-stage fluidized bed air distribution plate is formed by arranging air pipelines which are crossed transversely and longitudinally, and the air distribution plate is horizontally arranged; a hood is arranged at the intersection point of the gas pipeline; the gap size formed by the crossed gas pipelines is 15-20 mm.

Preferably, the bottom surface of the space below the air distribution plate of the primary fluidized bed is an inclined plate fixedly connected with the main body of the primary fluidized bed, the inclined plate forms an included angle of 5-10 degrees with the horizontal plane, and the primary fluidized bed is subjected to vibration action through motors arranged at four bottom corners of the fluidized bed.

A screw airflow bidirectional conveying mechanism which is in material communication with the upper surface of the sloping plate is arranged on one side of the lowest position of the sloping plate; the screw airflow bidirectional conveying mechanism comprises a horizontal conveying screw, wherein the lower part of the horizontal conveying screw is provided with a gas distributor axially arranged along the conveying screw, air flow is blown upwards through the gas distributor, light and small materials in the screw are blown away from the screw and returned to the upper space of the fluidized bed, and larger and heavier materials in the screw are discharged under the pushing action of the screw.

Preferably, the horizontal section of the primary fluidized bed is rectangular, and the length-width ratio is 2:1-4:1; to ensure a longer distance of movement and residence time of the bed material within the bed.

The boiling bed material of the primary fluidized bed enters the secondary fluidized bed through a first overflow port; and enabling a gas phase material flow flowing out of the top of the primary fluidized bed to enter a gas-solid separation unit, enabling the obtained gas phase material flow to enter a gas purification unit or a combustion unit, and collecting the obtained solid material which is powdery thermal conversion upgraded fuel for later use.

The air distribution plate of the secondary fluidized bed is a horizontal metal plate with a hood uniformly embedded on the surface, the lower part of the air distribution plate is an air chamber, and all bed materials are positioned on the upper part of the air distribution plate; the two-stage fluidized bed is provided with two bed material overflow outlets in the vertical direction, heavier materials are discharged from the lower second overflow outlet, and light materials are discharged from the upper third overflow outlet.

Preferably, the horizontal section of the fluidized bed of the secondary fluidization heat conversion screening device is rectangular, and the length-width ratio is 3:1-5:1; to ensure a longer distance of movement and residence time of the bed material within the bed.

Preferably, the vertical plane of the fluidized bed reactor of the secondary fluidization heat conversion screening device is rectangular, and the position of the upper overflow port is different from the position of the lower overflow port by more than 2 times of width.

Compared with the prior art, the invention has the following beneficial effects: the method has the advantages that the heat conversion crushing device is adopted to realize the side crushing and side heat conversion treatment of the household garbage, wherein a brittle product shell can be rapidly formed at a new section formed by crushing in the heat conversion process, the viscosity of materials is reduced, meanwhile, the product shell on the surface of the materials can be continuously crushed in the crushing process, the interior of the household garbage is exposed to the heat conversion atmosphere, and the obstruction of the product shell on the surface of the materials to the heat transfer of the interior of the household garbage materials is eliminated; that is, in the thermal conversion crushing step of the invention, the thermal conversion process and the crushing process can be mutually promoted, and better thermal conversion and crushing effects are objectively realized, and the dried materials can be crushed directly without cooling, so that heat loss is greatly reduced; the crushing part which rotates coaxially and reversely realizes the efficient crushing of household garbage materials, and the technical problem that massive materials enter a fluidized bed due to insufficient crushing so as to block a fluidization gas channel can be effectively avoided; through reasonable regulation and control of fluidization conditions, fluidization screening of materials such as metal blocks, glass slag, coarse and fine sand and the like mixed in household garbage material particles can be realized.

Drawings

FIG. 1 is a schematic flow chart of the process of the present invention;

FIG. 2 is a schematic diagram of a thermal conversion crushing device;

FIG. 3 is a schematic view of a crushing section fixedly connected to a stub shaft by a fixed disk;

FIG. 4 is a schematic illustration of the crushing section drivingly connected to a stub shaft through a planetary gear set;

FIG. 5 is a schematic view of a primary fluidized bed;

FIG. 6 is a schematic of a two-stage fluidized bed.

In the figure, 1 is a material inlet, 11 is a short shaft, 12 is a fixed disk, 13 is a central gear, 14 is a transmission gear, 15 is a gear ring, 2 is a second purge gas inlet, 3 is an outer cylinder, 31 is a second gas heat carrier inlet, 32 is a second gas heat carrier outlet, 33 is an outer cylinder heat insulation layer, 4 is an inner cylinder, 41 is a reversing bevel gear set, 42 is a shearing knife set, 43 is a rotary hammer set, 44 is a chain ball set, 5 is a second purge gas outlet, 6 is a material outlet, 7 is a primary fluidized bed, 71 is a primary fluidized bed feed inlet, 72 is a primary fluidized bed air distribution plate, 73 is a sloping plate, 74 is a third gas heat carrier outlet, 75 is a first overflow port, 76 is a partition plate, 77 is a return path, 8 is a secondary fluidized bed, 81 is a secondary fluidized bed feed inlet, 82 is a secondary fluidized bed air distribution plate, 83 is a fourth gas heat carrier outlet, 84 is a second overflow port, 85 is a third overflow port, 9 is a vibration device, and 10 is a screw airflow bidirectional conveying mechanism.

Detailed Description

Examples

To facilitate understanding of the present invention, examples are set forth below. It should be apparent to those skilled in the art that the examples are provided only to aid in understanding the present invention and should not be construed as limiting the invention in any way.

Example 1

The embodiment provides a household garbage thermal conversion-thermal separation coupling process, which comprises the following steps of:

s1, a drying step, which is used for drying the household garbage to remove a large amount of water contained in the household garbage;

s2, a thermal conversion crushing step, which is used for crushing and performing thermal conversion treatment on the dried household garbage to obtain massive and granular materials and powdery thermal conversion upgrading fuel;

s3, a first-stage fluidization heat conversion screening step, which is used for carrying out fluidization heat conversion screening treatment on the block-shaped and granular materials obtained by heat conversion crushing;

s4, a second-stage fluidization heat conversion screening step, which is used for carrying out fluidization heat conversion screening treatment on the materials discharged from the overflow port of the first-stage fluidized bed.

The operation temperature of the drying step is 120-180 ℃, and the water content of the material treated by the drying step is not more than 5%;

the heat required by the drying step is provided by a first gas heat carrier, the first gas heat carrier at least comprises a first sweeping gas part, and the first sweeping gas is in direct contact with the materials to be dried for heat and mass transfer; the gas phase stream produced after purging is passed through a combustion or flue gas cleaning system.

Specifically, a second gas heat carrier is provided for the materials to be crushed in the thermal conversion crushing step so as to realize the thermal conversion treatment while crushing. The second gas heat carrier at least comprises a second purge gas flowing along the surface of the material (the gas flowing direction is consistent with the material conveying direction), the second purge gas provides heat required by heat conversion for the material and entrains water evaporated from the surface of the material and fine product shell particles peeled off from the surface of the material due to crushing, the second purge gas then enters a gas-solid separation device to respectively obtain gas-phase products and powdery heat conversion upgraded fuels, and the large particles and blocks which are not fully converted enter a downstream first-stage fluidization heat conversion screening step.

The crushing form of the thermal conversion crushing step includes shearing and/or hammering. The operating temperature of the thermal conversion crushing device is 180-250 ℃.

The primary fluidized heat conversion screening treatment is performed by providing a third gaseous heat carrier to the lower portion of the primary fluidized bed.

The supply amount and the air speed of the third gas heat carrier are adjusted so that the bed material is in a boiling fluidization state in the fluidized bed.

Inorganic particles as grinding machine materials are in a boiling fluidization state in the primary fluidized bed; organic small particles with the density smaller than that of the grinding bed material and the particle size equivalent to that of the grinding bed material, peeled product shell particles and the like are discharged from the top of the primary fluidized bed along with the fluidizing gas, and the organic small particles are heated by the third gas heat carrier in the ascending process, so that thermal conversion occurs on the surfaces of the organic small particles and product shells are formed, and meanwhile, the grinding bed material in a boiling state and the continuous friction of inorganic particles are also born, and the friction effect enables the product shells on the surfaces of the organic small particles to peel off and enables new thermal conversion surfaces to be exposed to the third gas heat carrier. Organic particles with larger sizes are difficult to fluidize, accumulate at the bottom of the fluidized bed and rub against the bed material to continuously update the thermal conversion surface, and finally are converted into fluidizable small-size organic particles; the density of the metal block is higher than that of the grinding bed material, and the metal block cannot be fluidized under the fluidization air speed condition set by the embodiment, so that the metal block is enriched at the bottom of the bed layer.

The bottom of the primary fluidized bed is provided with a screw airflow bidirectional conveying mechanism which is used for discharging accumulated metal blocks, blowing light materials mixed in the metal blocks back into a gas phase space of the fluidized bed, settling larger organic matters again, fully contacting with a gas heat carrier and a grinding bed material, and continuously reacting and crushing; a first overflow outlet is provided in the middle upper part of the primary fluidized bed for distributing the accumulated inorganic particles and the organic components which have not yet been converted into the secondary fluidized bed.

The bottom of the primary fluidized bed is provided with a vibrating device. The vibrating device can improve the fluidization effect of uneven large-particle materials, and can convey heavy materials which cannot be fluidized and are deposited at the bottom of the bed into the screw airflow bidirectional conveying mechanism at the bottom of the primary fluidized bed under the action of inclined planes and gravity through mechanical vibration.

Preferably, the horizontal section of the primary fluidized bed is rectangular, and the length-width ratio is 2:1-4:1; to ensure that the bed material has longer movement distance and residence time in the bed;

and continuously introducing the materials discharged from the overflow port of the primary fluidized bed into the secondary fluidized bed for secondary fluidized heat conversion screening treatment.

In the secondary fluidized bed, the surface of the organic particles continuously undergoes a thermal conversion reaction and rubs with fluidized inorganic particles, and peeled product shell scraps are discharged from the top of the secondary fluidized bed; fine sand particles are discharged from an overflow port at the upper part of the secondary fluidized bed, and coarse sand and glass slag are discharged from an overflow port at the lower part of the secondary fluidized bed.

And the gas outlets at the tops of the first-stage fluidized bed and the second-stage fluidized bed are respectively connected with a gas-solid separation device for separating product shell fragments and/or organic particles carried by the fluidizing gas from the gas flow to obtain the thermal conversion upgraded fuel.

The horizontal section of the fluidized bed of the secondary fluidization heat conversion screening device is rectangular, and the length-width ratio is 3:1-5:1; to ensure that the bed material has longer movement distance and residence time in the bed;

the operating temperature of the secondary fluidization heat conversion screening device is 310-600 ℃.

Wherein the oxygen content of the first gas heat carrier is not more than 2%, the oxygen content of the second gas heat carrier is not more than 1%, and the oxygen content of the third and fourth gas heat carriers is not more than 0.5%.

Example 2

Referring to fig. 1-5, the embodiment provides a device for a household garbage thermal conversion-thermal separation coupling process, which comprises a drying device, a thermal conversion crushing device, a primary fluidization thermal conversion screening device and a secondary fluidization thermal conversion screening device which are sequentially communicated; the devices are communicated by heat preservation so as to reduce heat loss in the conveying process.

The drying device adopted in the embodiment is a rotary kiln drying device. Conventional drying devices in the art, such as screw conveyor drying devices, track type drying devices, etc., may also be employed.

The thermal conversion crushing device comprises an outer cylinder body 3 and an inner cylinder body 4, wherein the bottom of the outer cylinder body 3 is supported and fixed through a bracket 10; the inner cylinder 4 is rotatably sleeved in the outer cylinder 3, the left end and the right end of the inner cylinder 4 are beyond the outer cylinder 3 and are rotationally sealed with the outer cylinder 3, a jacket for circulating a second gas heat carrier is formed between the inner cylinder and the outer cylinder, and the two ends of the outer cylinder 3 are respectively provided with a second gas heat carrier air inlet 31 and a second gas heat carrier air outlet 32; the outer side of the outer cylinder body 3 is provided with a heat preservation layer 33.

The bottoms of the two ends of the inner cylinder 4, which are beyond the outer cylinder 3, are respectively provided with a pair of riding wheels, and the riding wheels are used for carrying out rolling support on the inner cylinder 4; the outer surface of one end of the inner cylinder 4 is also provided with a gear 8, and the gear 8 is matched with the driving device 7 to drive the inner cylinder 4 to rotate.

The two ends of the inner cylinder 4 are respectively provided with a feeding end cap and a discharging end cap, and the feeding end cap and the discharging end cap are both sealed with the inner cylinder 4 in a rotating way and do not rotate along with the inner cylinder 4. Wherein, the feeding end cap is provided with a material inlet 1 which is used for introducing the dried household garbage into the inner cylinder body, and a second purge gas inlet 2; the bottom of the discharging end cap is provided with a material outlet 6 for discharging the material subjected to the thermal conversion crushing treatment, and the top of the discharging end cap is provided with a second purge gas outlet 5; the second purge gas outlet 5 is connected with a gas-solid separation device.

The inside crushing subassembly that is equipped with of inner tube 4, crushing subassembly includes two-way pivot and sets up the epaxial crushing portion of two-way pivot, crushing portion includes shearing knife group 42 and/or rotary hammer group 43 and/or hammer group 44. The bidirectional rotating shaft consists of a plurality of sections of short shafts 11 and a reversing bevel gear set 41, and the reversing bevel gear set 41 enables two adjacent short shafts 11 to reversely rotate through three bevel gears which are sequentially meshed; crushing portions are provided on each of the stub shafts 11, respectively, so that the crushing portions on adjacent stub shafts 11 are reversely rotated. One end of at least one stub shaft 11 extends beyond the feed end cap or the discharge end cap of the inner barrel 4 and is drivingly connected to the power unit.

In order to further improve the crushing effect, a plurality of crushing parts are arranged on each short shaft 11, and the plurality of crushing parts on the same short shaft 11 have two opposite rotation reversals. Specifically, a part of the plurality of crushing parts on the same short shaft 11 is fixedly connected with the short shaft 11 through a fixed disc 12 fixedly sleeved on the short shaft 11 or directly, so that the first rotating direction is the same as the rotating shaft; the remaining crushing portion is then rotationally coupled to the stub shaft 11 by a planetary gear assembly so as to have a second rotational direction opposite to the stub shaft 11. The planetary gear assembly comprises a sun gear 13 fixedly sleeved with the short shaft 11, a transmission gear 14 meshed with the sun gear 13, a gear ring 15 meshed with the transmission gear 14, and a frame (not shown in the figure) for fixing and/or supporting the sun gear 13, the transmission gear 14 and the gear ring 15; the remaining crushing portion is fixed to the outer peripheral wall of the ring gear 15 and thus has a second rotational direction opposite to the stub shaft 11.

The crushing portions having opposite rotation directions on the same stub shaft 11 are arranged at intervals from each other.

The inner cylinder 4 is obliquely arranged to convey the material to be crushed to the material outlet 6 by utilizing the self gravity of the material. Alternatively, a conveying member (not shown) is provided in the inner cylinder 4. The conveying part can be a conveying belt with two ends respectively fixed in the charging and discharging cap cover and positioned at the lower part of the inner cylinder body 4; or the conveying component can be a helical blade fixed on the inner wall surface of the inner cylinder 4, and when the inner cylinder 4 rotates, the helical blade pushes the material to move towards the material outlet 6.

The primary fluidization heat conversion screening device comprises a primary fluidized bed 7, and a feed inlet 71 of the primary fluidized bed is communicated with a material outlet 6 of the heat conversion crushing device; as shown in fig. 5, the first-stage fluidized-bed air distribution plate 72 is formed by arranging gas pipelines which are crossed horizontally and longitudinally, and is horizontally arranged; the air outlet of the air pipeline is vertically upwards arranged; the gap size formed by the crossed gas pipelines is 15-20 mm. The middle upper part of the primary fluidized bed 7 is provided with a first overflow port 75, and the top of the primary fluidized bed is provided with a third gas heat carrier outlet 74; the secondary fluidized heat conversion screening device comprises a secondary fluidized bed 8, and a feed inlet 81 of the secondary fluidized bed is communicated with a first overflow port 75; the two-stage fluidized bed air distribution plate 82 is a horizontal metal plate with a hood uniformly embedded on the surface, the lower part of the air distribution plate is an air chamber, and all bed materials are positioned on the upper part of the air distribution plate; the two-stage fluidized bed 8 is provided with two bed material overflow outlets in the vertical direction, heavier materials are discharged from a lower second overflow outlet 85, and light materials are discharged from an upper third overflow outlet 84.

Preferably, the bottom surface of the lower space of the first-stage fluidized bed air distribution plate 72 is a sloping plate 73 fixedly connected with the first-stage fluidized bed main body, the included angle between the sloping plate 73 and the horizontal plane is 5-10 degrees, and the vibrating device 9 driven by a motor applies a vibrating action to the first-stage fluidized bed 7.

A screw airflow bidirectional conveying mechanism 10 which is in material communication with the upper surface of the inclined plate 73 is arranged on one side of the lowest position of the inclined plate 73; the screw airflow bidirectional conveying mechanism 10 comprises a horizontal conveying screw, wherein a gas distributor axially arranged along the conveying screw is arranged at the lower part of the horizontal conveying screw, airflow is blown upwards through the gas distributor, light and small materials in the screw are blown away from the screw and returned to the upper space of the fluidized bed, and larger and heavier materials in the screw are discharged under the pushing action of the screw.

Wherein the particles blown off from the screw gas flow bidirectional conveying mechanism 10 are returned to the upper part of the gas phase space of the primary fluidized bed 7 through an independent return path; specifically, by providing a partition plate 76 above the screw gas flow bidirectional conveying mechanism 10, a return path 77 communicating with the upper part of the gas phase space is constructed in the first fluidized bed 7; the bottom of the partition plate 76 is higher than the sloping plate 73, so that a passage for the bed material to enter the screw airflow bi-directional conveying mechanism 10 is formed.

Preferably, the horizontal section of the primary fluidized bed 7 is rectangular, and the length-width ratio is 2:1-4:1; to ensure a longer distance of movement and residence time of the bed material within the bed.

Preferably, the metal content of the non-fluidized bottom slag discharged by the screw of the screw airflow bidirectional conveying mechanism 10 is not less than 80%.

The boiling bed material of the primary fluidized bed 7 enters the secondary fluidized bed 8 through a first overflow port 75; the gas phase material flow flowing out from the top of the primary fluidized bed 7 enters a gas-solid separation unit, the obtained gas phase material flow enters a gas purification unit or a combustion unit, and the obtained solid material is powdery thermal conversion upgrading fuel and is collected for later use.

Preferably, the vertical section of the secondary fluidized bed 8 is rectangular, and the difference between the position of the upper overflow port and the position of the lower overflow port is more than 2 times of width.

Preferably, a vibrating device is arranged at the bottom of the secondary fluidized bed. The vibrating device can improve the fluidization effect of the uneven large-particle materials.

The lower part of the secondary fluidization heat conversion screening device overflows and discharges, mainly comprises glass slag and coarse sand grains, wherein the content of non-metal inorganic matters is not less than 95%, and is collected for later use; and (3) discharging the material overflowed from the upper part, mainly fine sand particles, wherein the content of non-metal inorganic matters is not less than 98%, and collecting the material for later use.

Preferably, the gas phase material flow of the secondary fluidization heat conversion screening device enters a gas-solid separation unit, the obtained gas phase material flow enters a gas purification unit or a combustion unit, and the obtained solid material is powdery heat conversion upgrading fuel and is collected for later use.

Preferably, the horizontal section of the secondary fluidized bed 8 is rectangular, and the length-width ratio is 3:1-5:1; to ensure a longer distance of movement and residence time of the bed material within the bed.

Application example 1

The method comprises the steps that the initial water content of a first household garbage raw material is 50%, the feeding amount is 2000kg/h, the feeding temperature is 30 ℃, the household garbage raw material enters a rotary kiln drying device with the solid discharging temperature being 140 ℃, a first gas heat carrier adopted by the device is hot flue gas with the oxygen content of 2%, and the water content of the household garbage is reduced to 3% after drying treatment. The dehydrated material from the drying device enters a thermal conversion crushing device with a discharge temperature of 228 ℃, a second gas heat carrier adopted by the device is hot flue gas with an oxygen content of 1%, and a gas phase material flow after treatment enters a gas-solid separation device to obtain thermal conversion quality-improving fuel; large-particle solid materials enter a downstream primary fluidization heat conversion screening device. The solid materials from the thermal conversion crushing device enter a first-stage fluidization thermal conversion screening device with the discharge temperature of 289 ℃, the adopted third gas heat carrier (fluidization gas) of the device is hot flue gas with the oxygen content of 0.5%, and the treated gas phase material flow enters a gas-solid separation device to obtain thermal conversion upgraded fuel; the non-fluidized bottom slag is discharged through a screw airflow bidirectional conveying mechanism at the bottom of the primary fluidized bed and is collected for standby; the boiling particles are discharged from the overflow port and enter a downstream secondary fluidization heat conversion screening device. The solid materials from the first-stage fluidization heat conversion screening device enter a second-stage fluidization heat conversion screening device with the discharging temperature of 550 ℃, a fourth gas heat carrier (fluidization gas) adopted by the device is hot flue gas with the oxygen content of 0.5%, and the treated gas phase material flow enters a gas-solid separation device to obtain heat conversion quality-improving fuel; discharging the materials with larger density and granularity from an overflow port at the lower part of the secondary fluidized bed, and collecting the materials for later use; the lighter and smaller particles are discharged from the system through an upper overflow port and collected for later use.

The heat conversion quality-improving fuel obtained by the three devices (a heat conversion crushing device, a primary fluidization heat conversion screening device and a secondary fluidization heat conversion screening device) has the total mass yield of 43 percent relative to the dry-base household garbage raw material, the particle size range of less than 1mm and the heat value of 23.3MJ/kg; the quality yield of the non-fluidized bottom slag recovered by the primary fluidization heat conversion screening device is 7%, the grain diameter range is 2 mm-15 mm, and the metal content is 82%; the yield of the solid material obtained from the overflow port at the lower part of the secondary fluidization heat conversion screening device is 3%, the grain diameter range is 2 mm-5 mm, and the content of nonmetallic inorganic matters is 95%; the yield of the solid material obtained from the overflow port at the upper part of the secondary fluidization heat conversion screening device is 14%, the particle size range is 0.5 mm-2 mm, and the content of non-metal inorganic matters is 98%.

Application example 2

No. two domestic garbage raw material with initial water content of 44.4%, feeding quantity of 1800kg/h and feeding temperature of 30 ℃. The same procedure as in application example 1 was adopted. The difference is that the solid discharge temperature in the drying step is 164 ℃; the discharging temperature of the thermal conversion crushing step is 210 ℃; the discharge temperature of the primary fluidization heat conversion screening step is 296 ℃; the discharge temperature of the secondary fluidization heat conversion screening step is 450 ℃. The gas heat carrier used in the four steps was identical to that of application example 1.

The heat conversion quality-improving fuel obtained by the three devices (a heat conversion crushing device, a primary fluidization heat conversion screening device and a secondary fluidization heat conversion screening device) has the total mass yield of 48 percent relative to the dry-base household garbage raw material, the particle size range of less than 1mm and the heat value of 23.5MJ/kg; the quality yield of the non-fluidized bottom slag recovered by the primary fluidization heat conversion screening device is 6%, the grain diameter range is 3 mm-12 mm, and the metal content is 80%; the yield of the solid material obtained from the overflow port at the lower part of the secondary fluidization heat conversion screening device is 8%, the grain diameter range is 2 mm-5 mm, and the content of nonmetallic inorganic matters is 96%; the yield of the solid material obtained from the overflow port at the upper part of the secondary fluidization heat conversion screening device is 12%, the particle size range is 0.5 mm-2 mm, and the content of non-metal inorganic matters is 99%.

Application example 3

No. three domestic garbage raw material, the initial water content is 37.5%, the feeding quantity is 1600kg/h, and the feeding temperature is 30 ℃. The same procedure as in application example 1 was adopted. The difference is that the solid discharging temperature in the drying step is 180 ℃; the discharging temperature of the thermal conversion crushing step is 250 ℃; the discharge temperature of the primary fluidization heat conversion screening step is 310 ℃; the discharge temperature of the secondary fluidization heat conversion screening step is 600 ℃. The gas heat carriers adopted in the four steps are all gasification gas of the quality-improving fuel of the household garbage.

The heat conversion quality-improving fuel obtained by the three devices (a heat conversion crushing device, a primary fluidization heat conversion screening device and a secondary fluidization heat conversion screening device) has the total mass yield of 35 percent relative to the dry-base household garbage raw material, the particle size range of less than 1mm and the heat value of 23.9MJ/kg; the quality yield of the non-fluidized bottom slag recovered by the primary fluidization heat conversion screening device is 2%, the grain diameter range is 2 mm-10 mm, and the metal content is 83%; the yield of the solid material obtained from the overflow port at the lower part of the secondary fluidization heat conversion screening device is 8%, the grain diameter range is 2 mm-5 mm, and the content of nonmetallic inorganic matters is 98%; the yield of the solid material obtained from the overflow port at the upper part of the secondary fluidization heat conversion screening device is 10%, the particle size range is 0.5 mm-2 mm, and the content of non-metal inorganic matters is 98%.

Application example 4

The initial water content of the No. four household garbage raw material is 28.6%, the feeding quantity is 1400kg/h, and the feeding temperature is 30 ℃. The same procedure as in application example 1 was adopted. The difference is that the solid discharging temperature in the drying step is 120 ℃; the discharging temperature of the thermal conversion crushing step is 180 ℃; the discharge temperature of the primary fluidization heat conversion screening step is 280 ℃; the discharge temperature of the secondary fluidization heat conversion screening step is 310 ℃; the gas heat carriers used in the four steps are pyrolysis gas at 600 ℃ of the quality improving fuel for the living garbage.

The heat conversion quality-improving fuel obtained by the three devices (a heat conversion crushing device, a primary fluidization heat conversion screening device and a secondary fluidization heat conversion screening device) has the total mass yield of 55 percent relative to the dry-base household garbage raw material, the grain size range of less than 1mm and the heat value of 22.7MJ/kg; the quality yield of the non-fluidized bottom slag recovered by the primary fluidization heat conversion screening device is 10%, the grain diameter range is 5 mm-15 mm, and the metal content is 85%; the yield of the solid material obtained from the overflow port at the lower part of the secondary fluidization heat conversion screening device is 10%, the grain diameter range is 2 mm-5 mm, and the content of nonmetallic inorganic matters is 97%; the yield of the solid material obtained from the overflow port at the upper part of the secondary fluidization heat conversion screening device is 15%, the particle size range is 0.5 mm-2 mm, and the content of non-metal inorganic matters is 99%.

Comparative example 1

The domestic waste feedstock and inlet conditions were the same as in example 1, but the process included only two units, drying and thermal conversion crushing, with the latter two fluidized thermal conversion screening units removed. The operating temperatures of the drying unit and the thermal conversion crushing unit were the same as in example 1. The results show that the mass yield of the obtained thermal conversion upgraded fuel relative to the dry-base household garbage raw material is 7%, the particle size range is less than 15mm, and the heat value is 21.3MJ/kg. The large-particle material obtained by recycling at the bottom of the thermal conversion crushing equipment has a mass yield of 85 percent relative to the dry-base household garbage raw material, and the composition is complex, and is a mixture of metal, non-metal inorganic matters and unconverted organic matter components. Compared with example 1, under this condition, the yield and the heat value of the heat conversion upgraded fuel were low, and multicomponent separation recovery could not be achieved.

Comparative example 2

The domestic waste feedstock and inlet conditions were the same as in example 1, but the process included only two units, drying and thermal conversion crushing, with the latter two fluidized thermal conversion screening units removed. The drying unit was operated under the same conditions as in example 1 and the thermal conversion crushing unit was operated at the same temperature as in the highest temperature secondary fluidized thermal conversion screening unit of example 1. The results show that the mass yield of the obtained thermal conversion upgraded fuel relative to the dry-base domestic garbage raw material is 18%, the particle size range is less than 0.7mm, and the heat value is 21.6MJ/kg. The large-particle materials obtained by recycling at the bottom of the thermal conversion crushing equipment have the particle size range of less than 10mm, the mass yield of the large-particle materials is 58 percent relative to the dry-basis household garbage raw materials, and the large-particle materials have complex compositions and are a mixture of metal, non-metal inorganic matters and unconverted organic matters. Compared with example 1, under this condition, the yield and the heat value of the heat conversion upgraded fuel were low, and multicomponent separation recovery could not be achieved.

Comparative example 3

The household garbage raw material and inlet conditions were the same as in example 1, except that in the thermal conversion crushing unit, the shearing and hammering internals for crushing the material were removed. The result shows that the domestic garbage materials are still larger blocks and have irregular shapes after passing through the unit due to the fact that the shearing and hammering inner members of the thermal conversion crushing unit are not arranged, so that the temperature rising rate inside the materials is low, the thermal conversion degree is low, the mass yield of the thermal conversion upgrading fuel obtained by the unit relative to the dry domestic garbage raw materials is 4%, the particle size range is smaller than 0.6mm, and the heat value is 21.8MJ/kg. And after the bulk materials at the bottom of the equipment enter the downstream primary fluidization heat conversion screening unit, even if a vibration mechanism is started, effective fluidization still cannot be realized, the fluidized bed has the problem of dead bed, continuous and stable material inlet and outlet cannot be formed, and the heat conversion reaction cannot be effectively carried out.

Comparative example 4

The household garbage raw material and the inlet conditions are the same as in the example 1, but a thermal conversion crushing unit is omitted in the process, and the process only comprises a drying unit and two fluidized thermal conversion screening units. The operating temperatures of the drying unit and both fluidized heat transfer screening units were the same as in example 1. The result shows that after the domestic garbage materials subjected to drying treatment are still softer, larger in blocks and quite irregular in shape, after the large-block materials at the bottom of the drying equipment enter the downstream primary fluidization heat conversion screening unit, even if a vibration mechanism is started, effective fluidization can not be realized, the fluidized bed is in a dead bed problem, continuous and stable material inlet and outlet can not be formed, and the heat conversion reaction can not be effectively carried out.

Comparative example 5

The raw materials and inlet conditions of the household garbage are the same as those of the embodiment 1, no gas heat carrier is introduced into the heat conversion crushing unit, and the materials are heated only through indirect heat exchange of a heat source outside the cylinder. The operating temperature of each unit was the same as in example 1. The results show that the material can only be heated by contacting with the wall due to the lack of the gas heat carrier in the thermal conversion crushing unit, the thermal conversion is slower, the embrittlement effect is poor, the crushing efficiency is reduced, the lower crushing efficiency inhibits the thermal conversion effect of the material, the yield of the thermal conversion upgraded fuel is reduced, and the metal recovery rate of the fluidization unit is also reduced.

The heat conversion quality-improving fuel obtained by the three devices (a heat conversion crushing device, a primary fluidization heat conversion screening device and a secondary fluidization heat conversion screening device) has the total mass yield of 32 percent relative to the dry-base household garbage raw material, the particle size range of less than 1mm and the heat value of 21.3MJ/kg; the quality yield of the non-fluidized bottom slag recovered by the primary fluidization heat conversion screening device is 14%, the grain diameter range is 2 mm-15 mm, and the metal content is 40%; the yield of the solid material obtained from the overflow port at the lower part of the secondary fluidization heat conversion screening device is 8%, the grain diameter range is 2 mm-5 mm, and the content of nonmetallic inorganic matters is 97%; the yield of the solid material obtained from the overflow port at the upper part of the secondary fluidization heat conversion screening device is 16%, the particle size range is 0.5 mm-2 mm, and the content of non-metal inorganic matters is 98%.

It should be noted that the above-mentioned embodiments are only specific implementation examples of the technical solution of the present invention, and not limiting the technical solution of the present invention, and the scope of the present invention is defined by the claims.

Claims

1. A household garbage thermal conversion-thermal separation coupling process is characterized in that: comprising the following steps performed in sequence:

s1, a drying step, wherein the operation temperature is 120-180 ℃, and the drying step is used for drying the household garbage so as to remove a large amount of water contained in the household garbage;

S2, performing heat conversion crushing, namely performing heat conversion treatment while crushing the material to be crushed by providing a second gas heat carrier for the material to be crushed, wherein the operation temperature is 180-250 ℃; the second gas heat carrier at least comprises a second purge gas flowing through the surface of the material to be crushed in a concurrent manner; the second purge gas provides heat required for thermal conversion to the material to be crushed and entrains moisture generated by thermal decomposition and fine fuel particles peeled off from the surface of the material; the fuel particles carried by the second purge gas are subjected to gas-solid separation to obtain powdery heat conversion upgraded fuel; the larger particles and the blocks which are not fully converted are sent to a first-stage fluidization heat conversion screening step; the second gas heat carrier comprises flue gas with the volume content of pyrolysis gas and/or gasification gas and/or oxygen not exceeding 1%;

s3, a primary fluidization heat conversion screening step, wherein the operation temperature is 280-310 ℃, and a primary fluidized bed is adopted for carrying out fluidization heat conversion screening treatment on the crushed materials; the fuel particles carried by the fluidization gas are subjected to gas-solid separation to obtain powdery thermal conversion upgraded fuel, heavy materials taking metal as a main component in the primary fluidized bed bottom material are discharged out of the system through a screw gas flow bidirectional conveying mechanism, and organic matters and inorganic matter particles which are not fully converted are discharged out of an overflow port of the primary fluidized bed and then are sent to a secondary fluidized thermal conversion screening step;

S4, a second-stage fluidization heat conversion screening step, wherein the operation temperature is 310-600 ℃, and a second-stage fluidized bed is adopted for carrying out fluidization heat conversion screening treatment on the materials discharged from an overflow port of the first-stage fluidized bed; the fuel particles carried by the fluidizing gas are subjected to gas-solid separation to obtain powdery thermal conversion upgraded fuel, heavier materials taking glass slag and coarse sand particles as main components are discharged from a lower overflow port of the secondary fluidized bed, and light materials taking fine sand particles as main components are discharged from an upper overflow port.

2. The domestic waste thermal conversion-thermal separation coupling process as claimed in claim 1, wherein: the water content of the material treated by the drying step is not more than 5%; the heat required for the drying step is provided by the first gas heat carrier; the first gas heat carrier comprises flue gas with a pyrolysis gas and/or gasification gas and/or oxygen volume content of not more than 2%.

3. The domestic waste thermal conversion-thermal separation coupling process as claimed in claim 1, wherein: performing a primary fluidized heat conversion screening process by providing a third gaseous heat carrier to a lower portion of the primary fluidized bed; forming grinding machine materials in the primary fluidized bed by inorganic particles generated in the thermal conversion crushing step, wherein the density of the grinding machine materials is smaller than that of metal aluminum but larger than that of fine organic matters and fine fuel particles in garbage; the grinding bed material is in a boiling and fluidization state in the fluidized bed by adjusting the supply amount and the gas speed of the third gas heat carrier, and the fluidization effect of the uneven particles is improved by mechanical vibration; the powdery thermal conversion upgraded fuel stripped from the surface of the organic material after grinding enters a gas phase along with the fluidization gas and goes to a gas-solid separation unit; the heavy components and part of large-particle organic matters are in a non-fluidized state and are deposited at the bottom of a bed to form a bottom material, and the bottom material enters a screw airflow bidirectional conveying mechanism under the action of mechanical vibration; the light materials in the base material are reversely blown back to the gas phase space of the fluidized bed in the screw gas flow bidirectional conveying mechanism, wherein large-particle organic matters which are not fully reacted are settled again and fully contacted with the gas heat carrier and the grinding bed material, and the light materials are continuously converted and continuously crushed to obtain powdery heat conversion quality-improving fuel; heavy materials in the bottom materials which are not blown back to the fluidized bed are discharged out of the system through a screw airflow bidirectional conveying mechanism, and the metal content of the discharged bottom materials is not less than 80%; the third gaseous heat carrier comprises flue gas having a pyrolysis gas and/or gasification gas and/or oxygen content of not more than 0.5% by volume.

4. A domestic waste thermal conversion-thermal separation coupling process as claimed in claim 3, wherein: overflowing materials of the first-stage fluidized bed enter the second-stage fluidized bed; introducing a fourth gas heat carrier from the bottom of the secondary fluidized bed as fluidizing gas; all materials are positioned at the upper part of the air distribution plate, the materials in the bed are in a boiling and fluidization state by adjusting the supply amount and the air speed of the fourth air heat carrier, and the fluidization effect of the uneven particles is improved by mechanical vibration; the powdery thermal conversion upgraded fuel enters a gas phase along with the fluidizing gas and goes to a gas-solid separation unit; and two material overflow outlets are respectively arranged in the vertical direction of the secondary fluidized bed, heavier materials are discharged from the lower overflow outlet, and light materials are discharged from the upper overflow outlet.

5. The household garbage thermal conversion-thermal separation coupling process as claimed in claim 4, wherein: the content of non-metal inorganic matters in overflow discharge at the lower part of the secondary fluidized bed is not less than 95%.

6. The domestic waste thermal conversion-thermal separation coupling process according to claim 5, wherein: the content of non-metal inorganic matters in overflow discharge at the upper part of the secondary fluidized bed is not less than 98%; the fourth gaseous heat carrier comprises flue gas having a pyrolysis gas and/or gasification gas and/or oxygen content of not more than 0.5% by volume.

7. A device for executing the household garbage thermal conversion-thermal separation coupling process of any one of claims 1-6, comprising a drying device, a thermal conversion crushing device, a primary fluidization thermal conversion screening device and a secondary fluidization thermal conversion screening device which are communicated in sequence; the heat preservation intercommunication between each device, its characterized in that: the thermal conversion crushing device comprises a fixed outer cylinder body (3) and an inner cylinder body (4) which is rotatably sleeved in the outer cylinder body (3), wherein the left end and the right end of the inner cylinder body (4) exceed the outer cylinder body (3) and are rotationally sealed with the outer cylinder body (3); the two ends of the inner cylinder body (4) are respectively provided with a feeding end cap and a discharging end cap, and the feeding end cap and the discharging end cap are both rotationally sealed with the inner cylinder body (4) and do not rotate along with the inner cylinder body (4); the feeding end cap is provided with a material inlet (1) and a second purge gas inlet (2); the bottom of the discharging end cap is provided with a material outlet (6), and the top of the discharging end cap is provided with a second purge gas outlet (5); the inner cylinder body (4) is internally provided with a crushing assembly.

8. The apparatus of claim 7, wherein: the crushing assembly comprises a bidirectional rotating shaft and a crushing part arranged on the bidirectional rotating shaft; the crushing part comprises a shearing knife group (42) and/or a rotary hammer group (43) and/or a hammer chain group (44); the bidirectional rotating shaft consists of a plurality of sections of short shafts (11) and a reversing bevel gear set (41), and the reversing bevel gear set (41) enables two adjacent short shafts (11) to reversely rotate through three bevel gears which are sequentially meshed; crushing parts are respectively arranged on the short shafts (11), so that the crushing parts on the adjacent short shafts (11) reversely rotate; one end of at least one short shaft (11) extends out of the feeding end cap or the discharging end cap of the inner cylinder (4) and is in driving connection with the power component.

9. The apparatus as recited in claim 8, wherein: each short shaft (11) is provided with a plurality of crushing parts, and one part of the crushing parts is fixedly connected with the short shaft (11) through a fixed disc (12) fixedly sleeved on the short shaft (11) or directly, so that the crushing parts have the same first rotation direction as the short shaft (11); the remaining crushing section is rotationally connected to the stub shaft (11) by means of a planetary gear assembly so as to have a second rotational direction opposite to the stub shaft (11).

10. The apparatus as claimed in claim 9, wherein: the planetary gear assembly comprises a central gear (13) fixedly sleeved with the short shaft (11), a transmission gear (14) meshed with the central gear (13), a gear ring (15) meshed with the transmission gear (14) and a frame for fixing and/or supporting the central gear (13), the transmission gear (14) and the gear ring (15); the remaining crushing portion is fixed to the outer peripheral wall of the ring gear (15).

11. The apparatus of claim 7, wherein: the primary fluidization heat conversion screening device comprises a primary fluidized bed (7), and a feed inlet of the primary fluidized bed is communicated with a material outlet (6) of the heat conversion crushing device; the horizontal section of the primary fluidized bed (7) is rectangular, and the length-width ratio is 2:1-4:1; the first-stage fluidized bed air distribution plate (72) is formed by arranging a plurality of crossed air pipelines which are horizontally arranged, an air cap is arranged at the crossing point of each air pipeline, the air pipelines are used for supplying a third air heat carrier to the first-stage fluidized bed, a first overflow port (75) is arranged at the upper middle part of the first-stage fluidized bed, and a third air heat carrier outlet (74) is arranged at the top of the first-stage fluidized bed; the secondary fluidization heat conversion screening device comprises a secondary fluidized bed (8), and a feed inlet of the secondary fluidized bed is communicated with a first overflow port (75); the second-stage fluidized bed air distribution plate (82) is a horizontal metal plate with uniformly embedded hoods on the surface, and an air chamber for supplying a fourth gas heat carrier is arranged below the second-stage fluidized bed air distribution plate; the tail end wall of the secondary fluidized bed (8) is respectively provided with a second overflow port (84) and a third overflow port (85) at different heights; the horizontal section of the secondary fluidized bed is rectangular, and the length-width ratio is 3:1-5:1; the difference in height between the second overflow port (84) and the third overflow port (85) is not less than 2 times the width of the secondary fluidized bed (8).

12. The apparatus as recited in claim 11, wherein: an inclined plate (73) is fixedly arranged below the first-stage fluidized bed air distribution plate (72), the included angle between the inclined plate and the horizontal plane is 5-10 degrees, a non-fluidized bed material accumulation area is formed between the first-stage fluidized bed air distribution plate (72) and the inclined plate (73), and large-particle materials and metal blocks fall into the bed material accumulation area through 15-20 mm air distribution plate pipeline gaps; the four feet of the primary fluidized bed (7) are respectively provided with a vibrating device (9) for applying vibration to the primary fluidized bed (7); the screw gas flow bidirectional conveying mechanism (10) communicated with the upper surface material of the inclined plate (73) is arranged on the outer side of the lowest position of the inclined plate (73), and comprises a horizontal conveying screw and a gas distributor arranged at the lower part of the horizontal conveying screw, purge gas is introduced into the screw gas flow bidirectional conveying mechanism (10) through the gas distributor, a baffle plate (76) is arranged above the screw gas flow bidirectional conveying mechanism (10), and a return path (77) communicated with the upper part of a gas phase space of the first-stage fluidized bed (7) is constructed; the bottom of the partition plate (76) is higher than the inclined plate (73) to form a passage for the bottom material to enter the screw airflow bidirectional conveying mechanism (10); the purging gas fluidizes light particles in the screw airflow bidirectional conveying mechanism (10) again and sends the light particles into the primary fluidized bed (7) again through a return path (77), and non-fluidized heavy materials are discharged out of the system under the pushing action of the screw; the secondary fluidized bed (8) is also provided with a vibrating device (9).