Method for producing combustible gas through chemical chain gasification of waste plastics by using red-mud-based composite bone-shell oxygen carrier
By combining waste plastic, bones and shells in kitchen waste with red mud, forming a composite oxygen carrier, and performing chemical chain gasification reaction at high temperatures, the problem of insufficient utilization of inert components in kitchen waste is solved, and efficient production and resource utilization of combustible gases are achieved.
Patent Information
- Application Number
- CN202510208941.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-25
- Publication Date
- 2025-05-30
AI Technical Summary
The prior art is difficult to effectively deal with inert components in complex components in kitchen waste, especially waste plastics and shellfish substances, resulting in insufficient resource utilization.
By combining the waste plastic, bones and shells in kitchen waste with industrial waste red mud, a red mud-based composite bone shell oxygen carrier is formed, and these materials are converted into combustible gas through chemical chain gasification reaction at high temperature.
It realizes efficient conversion of inert components in kitchen waste, improves the yield and hydrogen content of combustible gases, reduces disposal costs, and broadens the resource utilization path of red mud.
Smart Images
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Abstract
Description
Technical Field:
[0001] The present invention relates to the technical field of chemical looping gasification energy utilization of kitchen waste, and specifically relates to a method for producing combustible gas by chemical looping gasification of waste plastics using a red mud-based composite bone shell oxygen carrier. Background Art:
[0002] Currently, there are two major categories of treatment technologies for kitchen waste. One is traditional non-resource treatment technologies, mainly including landfill and incineration, etc. The other treatment technology is resource treatment technology, such as aerobic composting and anaerobic digestion, etc. Compared with traditional technologies, aerobic composting of kitchen waste has less impact on the environment and can achieve reduction, harmlessness, and resource utilization. However, the components of kitchen waste in China are relatively complex. From a physical composition perspective, it mainly includes water, meat, bones, rice, shells, and animal and vegetable oils, etc. In the biogas residues after aerobic composting and anaerobic digestion, there are still many inert components that are not easily degraded, such as plastic bags, shellfish bones, etc. How to deal with inert components still faces many challenges. Therefore, it is necessary to explore and develop new harmless utilization routes for inert components of kitchen waste to achieve resource disposal of waste plastics and inert components in kitchen waste and improve the added value of products. Summary of the Invention:
[0003] The purpose of the present invention is to provide a method for producing combustible gas by chemical looping gasification of waste plastics using a red mud-based composite bone shell oxygen carrier, to achieve efficient disposal of waste plastics and inert components in kitchen waste, and solve the problem of insufficient utilization of inert components in the existing kitchen waste treatment technology.
[0004] The present invention is realized through the following technical solutions:
[0005] A method for producing combustible gas by chemical looping gasification of waste plastics using a red mud-based composite bone shell oxygen carrier, the method comprising the following steps:
[0006] (1) Classify, dry, crush, calcine, and screen waste plastics, bones, and shells in the difficult-to-treat components after anaerobic and aerobic fermentation of kitchen waste; the calcination is carried out in a muffle furnace at 890 - 900 °C with a heating rate of 8 - 10 k / min for 6 - 8 h;
[0007] (2) Dry, grind, calcine, and screen industrial waste red mud and set it aside; the calcination is carried out in a muffle furnace at 890 - 900 °C with a heating rate of 8 - 10 k / min for 6 - 8 h;
[0008] (3) Grind and mix the bones and shells obtained in step (1) and the red mud obtained in step (2) in different mass ratios using an agate mortar tool and uniformly mix them, and then calcine them at a high temperature of 890 - 900 °C to form a composite oxygen carrier;
[0009] (4) Put the waste plastics obtained in step (1) into the hopper above the vertical tube furnace, and place the composite oxygen carrier obtained in step (3) in the vertical tube furnace;
[0010] (5) Introduce N 2 into the vertical tube furnace, and set the temperature of the vertical tube furnace to 950 °C. When the required temperature is reached, open the hopper to allow the waste plastics to fall into the heating zone of the quartz tube and contact with the composite oxygen carrier to start the gasification reaction. The reaction time is 20 - 40 min.
[0011] In step (1), the drying temperature of the waste plastics is 58 - 60 °C, and the drying temperature of the bones and shells is 110 - 120 °C; the drying time is 24 h; the size of the waste plastic particles obtained after screening is 0.5 - 0.9 mm, and the size of the bone and shell particles is 80 - 120 mesh.
[0012] In step (2), the drying temperature of the red mud is 110 - 120 °C; the drying time is 24 h; the size of the screened particles is 80 - 120 mesh.
[0013] In step (3), the mass ratio of bone to red mud is 0:1 - 2.5:1, preferably 1.5 - 2:1; most preferably 1.5:1, and the mass ratio of shell to red mud mixture is 0:1 - 2.5:1, preferably 2 - 2.5:1, most preferably 2:1; the mass ratio of bone to shell is 1:5 - 5:5, preferably 3:4 - 4:5, most preferably 3:4.
[0014] In step (3), the calcination time is 6 - 8 h, the heating rate is 10 k / min. After calcination, the composite oxygen carrier is screened to 80 - 100 mesh and stored in a 120 °C drying oven for standby.
[0015] In step (5), the flow rate of N 2 is 90 - 100 ml / min, and the heating rate of the tube furnace is 8 - 10 k / min.
[0016] After the gasification reaction in step (5), switch to dry air for an oxidation reaction for 30 min to realize the regeneration of the oxygen carrier.
[0017] Specifically, in step (5), the end of the quartz tube is connected to a tail gas purification device and a collection device to remove the tar and moisture in the tail gas and collect the combustible gas.
[0018] The tail gas purification device includes an ice bath cooling system and a discolored silica gel dryer; the collection device uses an aluminum foil gas sampling bag.
[0019] The components of the collected combustible gas are H 2 , CO, CH 4 etc.
[0020] The present invention utilizes the acidic sites on the surface of hydroxyapatite crystals in the bones of kitchen waste and the strongly basic CaO in shells, and through their synergistic effect, it can promote the dehydration and catalytic dehydrogenation reactions of the hydroxyl (-OH) and carboxyl (-COOH) groups in the tar molecules generated during the high-temperature pyrolysis gasification stage of plastics to be converted into unsaturated compounds, and then crack to generate small molecule gases such as H 2 , CO and CH 4 etc., and increase the hydrogen content. In addition, at high temperatures, Fe 2 O 3 in the red mud will form oxygen vacancies, enhancing the adsorption and activation ability of oxygen-containing compounds, and releasing molecular oxygen during the reduction process, which can promote the oxidative decomposition of waste plastics and improve the conversion efficiency. Therefore, the inert components of bones and shells in kitchen waste cooperate with red mud to reduce the formation of tar, increase the hydrogen content in combustible gases, and particularly can also increase the yield of combustible gases, achieving the efficient conversion of waste.
[0021] The beneficial effects of the present invention are as follows:
[0022] (1) The present invention utilizes the synergistic effect of the inert components of bones and shells in kitchen waste, and jointly constructs a composite oxygen carrier with industrial waste red mud to increase the hydrogen content in combustible gases when catalytically gasifying organic solid waste plastics in kitchen waste to produce combustible gas. In particular, it can also increase the yield of combustible gases; at the same time, it is cheaper, has a wide source, and can be reused compared with synthetic oxygen carriers, reducing the disposal cost and high-value and resource utilization of waste plastics, providing technical support for alleviating the energy and environmental pressure in China and expanding the resource disposal of other organic solid wastes.
[0023] (2) Through chemical looping gasification technology, the waste plastics and inert components (bones and shells) in kitchen waste and industrial bulk waste red mud are resourcefully and energy-efficiently co-disposed, achieving the purpose of treating waste with waste; at the same time, it also broadens the resource utilization path of red mud and reduces environmental pollution pressure. Specific implementation method:
[0024] The following is a further description of the present invention, rather than a limitation of the present invention.
[0025] The red mud used in the comparative examples and examples of the present invention comes from a certain aluminum smelter, and its XRF analysis results are shown in Table 1:
[0026] Table 1 XRF elemental analysis of red mud
[0027]
[0028] The bones and shells used in the examples of the present invention are selected from cafeteria swill. Its XRF analysis results are shown in Table 2:
[0029] Table 2 XRF elemental analysis of bones and shells
[0030]
[0031] Example 1: Method for producing combustible gas by chemical looping gasification of waste plastics using a red mud-based composite bone shell oxygen carrier
[0032] The method comprises the following steps:
[0033] (1) The waste plastics in the difficult-to-treat components after anaerobic and aerobic fermentation of kitchen waste are dried at 60 °C for 24 h and then processed into particles with a size of 0.5 - 0.9 mm; the bones and shells in the kitchen waste are classified, dried at 120 °C for 24 h, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then ground and pulverized into particles with a size of 80 - 120 mesh, and stored in a drying oven at 120 °C for standby.
[0034] (2) The red mud is dried at 120 °C for 24 h, ground, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then screened to a particle size of 80 - 120 mesh, and stored in a drying oven at 120 °C for standby.
[0035] (3) 1.2 g of bones and 1.5 g of shells obtained in step (1) are ground and mixed evenly with 0.6 g of red mud obtained in step (2) in an agate mortar, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then screened to a particle size of 80 - 120 mesh to obtain a composite oxygen carrier.
[0036] (4) 0.15 g of the waste plastics obtained in step (1) is placed in the upper hopper of a vertical tube furnace; the composite oxygen carrier obtained in step (3) is placed in the vertical tube furnace.
[0037] (5) N is introduced into the vertical tube furnace at a flow rate of 100 ml / min 2 , the temperature of the vertical tube furnace is set to 950 °C, and the heating rate is 10 k / min. When the required temperature is reached, the upper hopper is opened to allow the waste plastics to fall into the heating zone of the quartz tube to contact the composite oxygen carrier and start the gasification reaction. After 30 min of the reduction reaction time of the oxygen carrier, dry air with a flow rate of 100 ml / min is switched on for 30 min of the oxidation reaction to realize the regeneration of the composite oxygen carrier.
[0038] (6) An ice bath cooling system, a discolored silica gel dryer, and an aluminum foil gas sampling bag are connected in sequence at the end of the quartz tube.
[0039] Comparative Example 1: Method for producing combustible gas by chemical looping gasification of waste plastics using red mud (blank control)
[0040] The method comprises the following steps:
[0041] (1) After anaerobic and aerobic fermentation of kitchen waste, the waste plastics in the difficult-to-treat components are dried at 60 °C for 24 h and then processed into particles with a size of 0.5 - 0.9 mm.
[0042] (2) The red mud is dried at 120 °C for 24 h, ground, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, then sieved to a particle size of 80 - 120 mesh, and placed in a drying oven at 120 °C for storage for later use.
[0043] (3) Put 0.15 g of the waste plastics obtained in step (1) into the upper hopper of the vertical tube furnace; put 0.6 g of the red mud obtained in step (2) into the vertical tube furnace.
[0044] (4) Pass N at a rate of 100 ml / min into the vertical tube furnace. 2 , set the temperature of the vertical tube furnace to 950 °C and the heating rate to 10 k / min. When the required temperature is reached, open the upper hopper to allow the waste plastics to fall into the heating zone of the quartz tube and contact with the red mud oxygen carrier to start the gasification reaction. After 30 min of the reduction reaction time of the oxygen carrier, switch to dry air with a flow rate of 100 ml / min and carry out the oxidation reaction for 30 min to realize the regeneration of the red mud oxygen carrier.
[0045] (5) Connect an ice bath cooling system, a discolored silica gel dryer, and an aluminum foil gas sampling bag in sequence at the end of the quartz tube.
[0046] Comparative Example 2: A method for chemical looping gasification of waste plastics to produce combustible gas using a red mud-based composite bone oxygen carrier
[0047] It includes the following steps:
[0048] (1) After anaerobic and aerobic fermentation of kitchen waste, the waste plastics in the difficult-to-treat components are dried at 60 °C, and after a drying time of 24 h, they are processed into particles with a size of 0.5 - 0.9 mm; the bones in the kitchen waste are dried at 120 °C for 24 h, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, then ground and crushed into particles with a size of 80 - 120 mesh, and placed in a drying oven at 120 °C for storage for later use.
[0049] (2) The red mud is dried at 120 °C for 24 h, ground, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, then sieved to a particle size of 80 - 120 mesh, and placed in a drying oven at 120 °C for storage for later use.
[0050] (3) Grind and mix 1.2 g of the bones obtained in step (1) and 0.6 g of the red mud obtained in step (2) evenly in an agate mortar, calcine in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then sieve to a particle size of 80 - 120 mesh to obtain a composite oxygen carrier.
[0051] (4) Put 0.15 g of waste plastic obtained in step (1) into the hopper above the vertical tube furnace; put the composite oxygen carrier obtained in step (3) into the vertical tube furnace.
[0052] (5) Pass N at a flow rate of 100 ml / min into the vertical tube furnace 2 , set the temperature of the vertical tube furnace to 950 °C, and the heating rate to 10 k / min. When the required temperature is reached, open the upper hopper to allow the waste plastic to fall into the heating zone of the quartz tube and contact the composite oxygen carrier to start the gasification reaction. After 30 min of the reduction reaction of the oxygen carrier ends, switch to dry air with a flow rate of 100 ml / min and carry out the oxidation reaction for 30 min to realize the regeneration of the composite oxygen carrier.
[0053] (6) Connect an ice bath cooling system, a discolored silica gel dryer, and an aluminum foil gas sampling bag to the end of the quartz tube in sequence.
[0054] Comparative Example 3: A method for producing combustible gas by chemical looping gasification of waste plastic using a red mud-based composite shell oxygen carrier
[0055] It includes the following steps:
[0056] (1) The waste plastic in the difficult-to-treat components after anaerobic and aerobic fermentation of kitchen waste is dried at 60 °C for 24 h and then processed into particles with a size of 0.5 - 0.9 mm; classify the shells in the kitchen waste, dry them at 120 °C for 24 h, and calcine them in a muffle furnace at 900 °C and a heating rate of 10 k / min for 6 h, then grind and crush them into particles with a size of 80 - 120 mesh. Store them in a drying oven at 120 °C for standby.
[0057] (2) Dry the red mud at 120 °C for 24 h, then grind it, calcine it in a muffle furnace at 900 °C and a heating rate of 10 k / min for 6 h, and then screen it to a particle size of 80 - 120 mesh, and store it in a drying oven at 120 °C for standby.
[0058] (3) Grind and mix 1.5 g of the shell obtained in step (1) and 0.6 g of the red mud obtained in step (2) evenly in an agate mortar, calcine them in a muffle furnace at 900 °C and a heating rate of 10 k / min for 6 h, and then screen them to a particle size of 80 - 120 mesh to obtain the composite oxygen carrier.
[0059] (4) Put 0.15 g of waste plastic obtained in step (1) into the hopper above the vertical tube furnace; put the composite oxygen carrier obtained in step (3) into the vertical tube furnace.
[0060] (5) Pass N at a flow rate of 100 ml / min into the vertical tube furnace 2, set the temperature of the vertical tube furnace to 950 °C and the heating rate to 10 k / min. When the required temperature is reached, open the upper bunker to let the waste plastics fall into the heating zone of the quartz tube to contact with the composite oxygen carrier and start the gasification reaction. After 30 minutes of the reduction reaction of the oxygen carrier ends, switch to dry air with a flow rate of 100 ml / min and carry out the oxidation reaction for 30 minutes to realize the regeneration of the composite oxygen carrier.
[0061] (6) Connect an ice bath cooling system, a discolored silica gel dryer, and an aluminum foil gas sampling bag to the end of the quartz tube in sequence.
[0062] Example 2: A method for chemical looping gasification of waste plastics by an iron red mud-based composite bone shell oxygen carrier to produce combustible gas
[0063] It includes the following steps:
[0064] (1) After anaerobic and aerobic fermentation of kitchen waste, the waste plastics in the difficult-to-treat components are dried at 60 °C for 24 h and then processed into particles with a size of 0.5 - 0.9 mm; classify the bones and shells in the kitchen waste, dry them at 120 °C, with a drying time of 24 h, and calcine them in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then grind and crush them into particles with a size of 80 - 120 mesh. Store them in a drying oven at 120 °C for standby.
[0065] (2) Dry the iron red mud at 120 °C for 24 h, then grind it, calcine it in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then screen it to a particle size of 80 - 120 mesh. Store it in a drying oven at 120 °C for standby.
[0066] (3) Grind and mix 0.9 g of bones and 1.2 g of shells obtained in step (1) with 0.6 g of iron red mud obtained in step (2) evenly in an agate mortar, calcine it in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then screen it to a particle size of 80 - 120 mesh to obtain the composite oxygen carrier.
[0067] (4) Put 0.15 g of waste plastics obtained in step (1) into the upper bunker of the vertical tube furnace; put the composite oxygen carrier obtained in step (3) into the vertical tube furnace.
[0068] (5) Pass 100 ml / min of N 2 , set the temperature of the vertical tube furnace to 950 °C and the heating rate to 10 k / min. When the required temperature is reached, open the upper bunker to let the waste plastics fall into the heating zone of the quartz tube to contact with the composite oxygen carrier and start the gasification reaction. After 30 minutes of the reduction reaction of the oxygen carrier ends, switch to dry air with a flow rate of 100 ml / min and carry out the oxidation reaction for 30 minutes to realize the regeneration of the composite oxygen carrier.
[0069] (6) Connect an ice bath cooling system, a discolored silica gel desiccator, and an aluminum foil gas sampling bag to the end of the quartz tube in sequence.
[0070] Comparative Example 4: A method for producing combustible gas by chemical looping gasification of waste plastics using a red mud-based composite bone oxygen carrier
[0071] It includes the following steps:
[0072] (1) The waste plastics in the difficult-to-treat components after anaerobic and aerobic fermentation of kitchen waste are dried at 60 °C for 24 h and then processed into particles with a size of 0.5 - 0.9 mm; the bones and shells in the kitchen waste are classified, dried at 120 °C for 24 h, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then ground and pulverized into particles with a size of 80 - 120 mesh. Place them in a drying oven at 120 °C for storage and standby.
[0073] (2) The red mud is dried at 120 °C for 24 h and then ground, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then screened to a particle size of 80 - 120 mesh, and placed in a drying oven at 120 °C for storage and standby.
[0074] (3) Grind and mix 0.9 g of the bones obtained in step (1) and 0.6 g of the red mud obtained in step (2) evenly in an agate mortar, calcine in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then screen to a particle size of 80 - 120 mesh to obtain a composite oxygen carrier.
[0075] (4) Put 0.15 g of the waste plastics obtained in step (1) into the hopper above the vertical tube furnace; put the composite oxygen carrier obtained in step (3) into the vertical tube furnace.
[0076] (5) Pass N 2 with a flow rate of 100 ml / min into the vertical tube furnace, set the temperature of the vertical tube furnace to 950 °C, and the heating rate to 10 k / min. When the required temperature is reached, open the upper hopper to make the waste plastics fall into the heating area of the quartz tube to contact the composite oxygen carrier and start the gasification reaction. After 30 min of the reduction reaction time of the oxygen carrier ends, switch to dry air with a flow rate of 100 ml / min and carry out an oxidation reaction for 30 min to realize the regeneration of the composite oxygen carrier.
[0077] (6) Connect an ice bath cooling system, a discolored silica gel desiccator, and an aluminum foil gas sampling bag to the end of the quartz tube in sequence.
[0078] Comparative Example 5: A method for producing combustible gas by chemical looping gasification of waste plastics using a red mud-based composite shell oxygen carrier
[0079] It includes the following steps:
[0080] (1) After drying the waste plastics, which are difficult to treat in the components of food waste after anaerobic and aerobic fermentation, at 60 °C for 24 h, they are processed into particles with a size of 0.5 - 0.9 mm; the shells in the food waste are classified, dried at 120 °C for 24 h, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then ground and pulverized into particles with a size of 80 - 120 mesh. They are placed in a drying oven at 120 °C for storage and standby.
[0081] (2) After drying the red mud at 120 °C for 24 h, it is ground, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then screened to a particle size of 80 - 120 mesh. It is placed in a drying oven at 120 °C for storage and standby.
[0082] (3) 1.2 g of the shells obtained in step (1) and 0.6 g of the red mud obtained in step (2) are ground and mixed evenly in an agate mortar, calcined in a muffle furnace at 900 °C with a heating rate of 10 k / min for 6 h, and then screened to a particle size of 80 - 120 mesh to obtain a composite oxygen carrier.
[0083] (4) 0.15 g of the waste plastics obtained in step (1) is placed in the upper hopper of a vertical tube furnace; the composite oxygen carrier obtained in step (3) is placed in the vertical tube furnace.
[0084] (5) Pass N 2 with a flow rate of 100 ml / min into the vertical tube furnace, set the temperature of the vertical tube furnace to 950 °C, and the heating rate to 10 k / min. When the required temperature is reached, open the upper hopper to allow the waste plastics to fall into the heating zone of the quartz tube and come into contact with the composite oxygen carrier to start the gasification reaction. After 30 min of the reduction reaction of the oxygen carrier ends, switch to dry air with a flow rate of 100 ml / min and carry out the oxidation reaction for 30 min to realize the regeneration of the composite oxygen carrier.
[0085] (6) Connect an ice bath cooling system, a discolored silica gel dryer, and an aluminum foil gas sampling bag to the end of the quartz tube in sequence.
[0086] Table 3 Yields of pyrolysis waste plastic combustible gas and total combustible gas yields in Comparative Examples 1 - 5 and Examples 1 - 2
[0087]
[0088] As can be seen from Table 3, compared with Comparative Examples 1 - 3 in Example 1, and compared with Comparative Examples 1, 4 - 5 in Example 2, it can be known that both the inert components bone and shell in the food waste are added, and the mass ratio of bone to shell is 3:4 - 4:5. The two act synergistically to jointly construct a composite oxygen carrier with industrial waste red mud to improve the hydrogen content in the combustible gas when catalyzing the gasification of organic solid waste plastics in food waste to produce combustible gas. In particular, in Example 2, the CO content in the combustible gas and the total combustible gas yield are also increased.
Claims
1. A method for producing combustible gas by chemical chain gasification of waste plastics using a red mud-based composite bone shell oxygen carrier, characterized in that: The method comprises the following steps: (1) Classifying and drying, crushing, calcining, and screening the waste plastics, bones, and shells in the difficult-to-treat components of the kitchen waste after anaerobic and aerobic fermentation; the calcination is carried out in a muffle furnace at 890-900° C. and a heating rate of 8-10 k / min for 6-8 hours; (2) drying, grinding, calcining, and screening the industrial waste red mud for later use; the calcination is carried out in a muffle furnace at 890-900° C. and a heating rate of 8-10 k / min for 6-8 hours; (3) grinding and mixing the bones and shells obtained in step (1) and the red mud obtained in step (2) in different mass ratios using an agate mortar tool, and calcining at a high temperature of 890 to 900° C. to form a composite oxygen carrier; (4) placing the waste plastics obtained in step (1) into a silo above a vertical tube furnace, and placing the composite oxygen carrier obtained in step (3) in the vertical tube furnace; (5) N2 is introduced into the vertical tube furnace, and the temperature of the vertical tube furnace is set to 950°C. When the temperature reaches the required temperature, the silo is opened to allow the waste plastic to fall into the quartz tube heating zone and contact with the composite oxygen carrier to start a gasification reaction. The reaction time is 20 to 40 minutes.
2. The method according to claim 1, characterized in that In step (1), the drying temperature of the waste plastic is 58-60° C., and the drying temperature of bones and shells is 110-120° C.; the drying time is 24 hours; the waste plastic particles obtained after screening have a size of 0.5-0.9 mm, and the bone and shell particles have a size of 80-120 mesh.
3. The method according to claim 1, characterized in that In step (2), the red mud drying temperature is 110-120° C.; the drying time is 24 hours; and the sieved particle size is 80-120 mesh.
4. The method according to claim 1, characterized in that: In step (3), the mass ratio of bones to red mud is 0:1 to 2.5:1, the mass ratio of shells to red mud is 0:1 to 2.5:1, and the mass ratio of bones to shells is 1:5 to 5:
5.
5. The method according to claim 1, characterized in that In step (3), the mass ratio of bones to red mud is 1.5-2:1, the mass ratio of shells to red mud is 2-2.5:1, and the mass ratio of bones to shells is 3:4-4:
5.
6. The method according to claim 1, characterized in that In step (3), the calcination time is 6 to 8 hours, the heating rate is 10k / min, and after the calcination is completed, the composite oxygen carrier is sieved to 80 to 100 mesh and stored in a 120°C drying oven for use.
7. The method according to claim 1, characterized in that In step (5), the N2 flow rate is 90-100 ml / min, and the heating rate of the tubular furnace is 8-10 k / min.
8. The method according to claim 1, characterized in that After the gasification reaction in step (5) is completed, the air is switched to dry air and an oxidation reaction is carried out for 30 minutes to achieve regeneration of the oxygen carrier.
9. The method according to claim 1, characterized in that: In particular, in step (5), the end of the quartz tube is connected to a tail gas purification device and a collection device, and the combustible gas is collected after removing impure tar and water from the tail gas.
10. The method according to claim 1, characterized in that The tail gas purification device comprises an ice bath cooling system and a color-changing silica gel dryer; and the collecting device adopts an aluminum foil gas collection bag.