System and method for preparing high-quality synthesis gas from household garbage and carbon dioxide

Abstract

The invention discloses a system and a method for preparing high-quality synthesis gas from household garbage and carbon dioxide, the household garbage is firstly dewatered by a dryer, and then enters a low-temperature pyrolysis reactor, a medium-temperature pyrolysis reactor and a high-temperature pyrolysis reactor in sequence for pyrolysis and gasification reaction. Pyrolysis gas generated by the low-temperature pyrolysis reactor and the medium-temperature pyrolysis reactor passes through a dechlorination device and then enters a combustion chamber to be combusted to generate high-temperature flue gas to provide a heat source required by pyrolysis reaction. Carbon dioxide is introduced into the high-temperature pyrolysis reactor to perform gasification reaction with medium-temperature carbon, and synthesis gas generated after reaction enters the heat exchanger to perform heat exchange with cold water. And after the heat-exchanged synthesis gas enters a dryer to dry the household garbage, high-quality synthesis gas at low temperature can be obtained. External heat source supply is not needed, pyrolysis gasification reaction is carried out through heat provided by the household garbage, the pyrolysis efficiency and the energy self-sufficiency rate of the household garbage can be improved, generation and release of harmful substances containing chlorine and the like are effectively controlled, and environment friendliness and economical efficiency are both considered.

Description

Technical Field

[0001] The present invention belongs to the field of waste treatment, energy recovery and resource utilization, in particular to a pyrolysis and recycling technology for domestic waste, and relates to a system and method for producing high-quality synthesis gas from domestic waste and carbon dioxide. Background Art

[0002] With socioeconomic development and the continuous improvement of living standards, the amount of domestic waste generated continues to rise, and its composition is becoming increasingly complex, becoming a major obstacle to sustainable urban development. Currently, domestic waste contains a large amount of waste, including discarded cardboard, plastics, waste rubber, textiles, synthetic leather, and other complex components, making direct resource utilization difficult. Efficient, environmentally friendly, and economical disposal of domestic waste has become a critical issue in the field of solid waste treatment technology.

[0003] Current methods for treating domestic waste primarily rely on landfill, incineration, and biological treatment. While landfill, while relatively inexpensive, presents numerous challenges, including large land occupation, resource waste, leachate pollution, and greenhouse gas emissions, making it increasingly difficult to meet environmental standards. Incineration can rapidly reduce waste, but for domestic waste with complex composition and high levels of harmful components like chlorine, it can easily generate hazardous substances like dioxins, and its energy recovery rate is low. Biological treatment, however, is limited by the complexity of waste composition and its limited scope of application, making it difficult to address the comprehensive treatment of domestic waste on its own.

[0004] To address these issues, pyrolysis and gasification technologies, as a treatment process with advantages in waste reduction, harmlessness, and resource utilization, have received widespread attention in recent years. The pyrolysis process converts domestic waste into combustible gases, tar, and charcoal under anaerobic or anoxic conditions, and has excellent resource recovery potential. However, existing pyrolysis technologies still have certain shortcomings when applied to domestic waste treatment. For example, the pyrolysis process lacks reasonable zone temperature control, resulting in unstable product composition; the chlorine-containing components in the waste are released in a disorderly manner, increasing the burden of gas purification; and the high-temperature gasification and combustion units are not highly integrated, resulting in limited utilization efficiency of thermal energy and gas resources.

[0005] Chlorides in domestic waste primarily originate from chlorine-containing plastics, waste textiles, and paper products. Relevant literature indicates that when these chlorine-containing substances reach 350°C to 420°C during pyrolysis, they begin to decompose and release chlorine. The longer the temperature is maintained at 380°C to 420°C, the more effective it is for complete chlorine release from the waste. Chlorine removal during the pyrolysis of domestic waste is particularly important. Effective chlorine removal can significantly reduce hydrogen chloride emissions, minimize equipment corrosion during subsequent combustion or gasification, and inhibit the formation of highly toxic pollutants such as dioxins, thereby improving the cleanliness of the exhaust gas. Reducing the presence of chlorides during domestic waste treatment can also improve the quality of the gasification synthesis gas and reduce back-end purification costs. Summary of the Invention

[0006] In response to the problems existing in the prior art, the present invention provides a system and method for producing high-quality synthesis gas from domestic waste and carbon dioxide. The domestic waste pyrolysis system does not require an external heat source, can effectively solve the heat source supply problem in traditional pyrolysis technology, and maximize the economy and resource utilization rate of domestic waste treatment.

[0007] The present invention is achieved through the following technical solutions: A system for producing high-quality synthesis gas from domestic waste and carbon dioxide, comprising: a feeder, a dryer, a low-temperature pyrolysis reactor, a medium-temperature pyrolysis reactor, and a high-temperature pyrolysis reactor connected in sequence; The pyrolysis gas outlets of the low-temperature pyrolysis reactor and the medium-temperature pyrolysis reactor are connected to the dechlorination device and the combustion chamber in sequence; The flue gas outlet of the combustion chamber is connected in sequence to the flue gas pipelines of the high-temperature pyrolysis reactor, the medium-temperature pyrolysis reactor, the low-temperature pyrolysis reactor, and the flue gas purifier; The synthesis gas outlet of the high-temperature pyrolysis reactor is connected to the heat exchanger and the dryer in sequence.

[0008] Preferably, the dryer, low-temperature pyrolysis reactor, medium-temperature pyrolysis reactor, and high-temperature pyrolysis reactor all adopt a dual-chamber structure, including an inner chamber and an outer chamber. The inner chamber is provided with a material guide plate, and the outer chamber is provided with a flue gas guide vane. Each reactor forms a flue gas circulation loop with the combustion chamber through a heat exchanger.

[0009] Preferably, the operating temperature of the dryer is 105-150°C; The operating temperature of the low-temperature pyrolysis reactor is 150-450°C, and the material residence time is 30-80 minutes; The medium-temperature pyrolysis reactor has an operating temperature of 450-600°C and a material residence time of 20-40 minutes; The operating temperature of the high-temperature pyrolysis reactor is 600-1000° C., and the material residence time is 10-30 minutes.

[0010] Preferably, a first induced draft fan is provided on the pipeline between the heat exchanger and the dryer.

[0011] Preferably, a valve is provided on the carbon dioxide inlet pipeline of the high-temperature pyrolysis reactor.

[0012] Preferably, a second induced draft fan is provided on the outlet pipeline of the flue gas purifier.

[0013] Preferably, the feed inlet of the dryer is provided with a sealing device.

[0014] Preferably, the dryer, low-temperature pyrolysis reactor, medium-temperature pyrolysis reactor, and high-temperature pyrolysis reactor are all equipped with a PLC control unit and an automatic adjustment module, and closed-loop control of the temperature, flue gas flow, and material residence time of each zone is achieved through temperature sensors, flow meters, and online detectors for hydrogen chloride and hydrogen sulfide.

[0015] Preferably, the dechlorination device is provided with an absorbent spiral feeding system and a mixing reaction chamber, and calcium hydroxide dry powder is used as the absorbent.

[0016] A method for producing high-quality synthesis gas from domestic waste and carbon dioxide comprises the following steps: Domestic waste enters the dryer through the feeder, where it is dehydrated at 105-150°C to obtain dry material; The dried material is sequentially fed into a low-temperature pyrolysis reactor, a medium-temperature pyrolysis reactor, and a high-temperature pyrolysis reactor to undergo multi-stage pyrolysis and gasification reactions; The pyrolysis gas generated by multi-stage pyrolysis is dechlorinated by the dechlorination device and then enters the combustion chamber for combustion. The high-temperature flue gas generated by the combustion flows through the high-temperature pyrolysis reactor, the medium-temperature pyrolysis reactor, and the low-temperature pyrolysis reactor in sequence. After the heat required for pyrolysis is provided by indirect heat exchange, the flue gas is treated by the flue gas purifier and then discharged; Carbon dioxide is introduced into the high-temperature pyrolysis reactor to react with medium-temperature charcoal to generate synthesis gas. The synthesis gas is cooled by the heat exchanger and then enters the dryer to dry the domestic waste, and finally outputs high-quality synthesis gas.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: 1) The system and method provided by this invention can effectively improve the pyrolysis efficiency of domestic waste. Through a precise multi-stage heat exchange zone design, targeted pyrolysis and gasification reactions can be carried out at different temperatures, improving the resource utilization efficiency of domestic waste. Each temperature zone can effectively control and optimize the pyrolysis and gasification reaction temperatures of domestic waste, improving the conversion efficiency of gasification synthesis gas.

[0018] 2) The system and method provided by this invention can efficiently recycle domestic waste resources and reduce energy consumption. Pyrolysis oil and gas generated in the low-temperature and medium-temperature zones undergo dechlorination before entering the combustion chamber. The resulting high-temperature flue gas is fed into the pyrolysis reactor to provide a heat source, reducing external energy demand and lowering costs. In the high-temperature zone, the pyrolysis products from the medium-temperature zone are gasified with carbon dioxide to produce high-quality syngas, which can be recovered as fuel or a chemical feedstock.

[0019] 3) The system and method provided by this invention effectively remove harmful substances. Through precise airflow control and temperature regulation in the low- and medium-temperature zones, harmful elements such as chlorine and sulfur in the waste are converted to the maximum extent possible into the pyrolysis gas stream. The generated pollutants, such as hydrogen chloride and hydrogen sulfide, are then passed along with the pyrolysis gas stream into a dechlorination device for removal. The pyrolysis gas stream, after passing through the dechlorination device, enters the combustion chamber, where it is burned to generate high-temperature flue gas, which provides heat for the pyrolysis reaction. This process not only improves system safety and operational stability, but also prevents the formation of large amounts of pollutants in the gas.

[0020] 4) The present invention introduces carbon dioxide as a gasifying agent to participate in the high-temperature gasification reaction of domestic waste, which not only achieves the efficient generation of high-quality combustible gas, but also realizes the resource reuse of CO2, giving CO2 secondary utilization value, which is in line with the goal of coordinated utilization of domestic waste resources and high value of CO2, and helps to build a green and low-carbon solid waste treatment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a schematic diagram of a system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to the present invention; In the figure: 1-feeder; 2-dryer; 3-low-temperature pyrolysis reactor; 4-medium-temperature pyrolysis reactor; 5-high-temperature pyrolysis reactor; 6-first induced draft fan; 7-heat exchanger; 8-combustion chamber; 9-chlorine removal device; 10-flue gas purifier; 11-second induced draft fan; 12-valve. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] A pyrolysis technology solution suitable for treating domestic waste can achieve efficient removal of chlorides from domestic waste through effective segmented temperature control, atmosphere regulation, and product diversion design. This promotes the high-value utilization of resources such as combustible gas and tar, effectively controls the generation and emission of harmful gases such as dioxins, and ensures the output of high-quality gasification synthesis gas, thus meeting the demand for green, environmentally friendly, and low-carbon domestic waste treatment technologies. To address these issues, the present invention proposes a multi-zone coordinated pyrolysis treatment system for domestic waste, which can achieve efficient and clean pyrolysis of domestic waste and resource utilization of synthesis gas, and has good application prospects.

[0025] The present invention provides a system and method for producing high-quality synthesis gas from domestic waste and carbon dioxide. The system includes: a feeder 1, a dryer 2, a low-temperature pyrolysis reactor 3, a medium-temperature pyrolysis reactor 4, a high-temperature pyrolysis reactor 5, a dechlorination device 9, a combustion chamber 8, a flue gas purifier 10, a heat exchanger 7, a first induced draft fan 6, a first induced draft fan 11, and a valve 12.

[0026] Dryer 2 consists of an inner chamber and an outer chamber, each with an inlet and outlet. The inlet is sealed to prevent hot air from flowing back into the chamber. Dryer 2 operates at a temperature of 105-150°C, monitored and controlled by a temperature sensor. Dryer 2 uses a circulating hot air blower to dry the raw materials, keeping the humidity below 10%.

[0027] The low-temperature pyrolysis reactor 3 consists of an inner chamber and an outer chamber, both of which are equipped with an inlet and an outlet. The operating temperature of the low-temperature pyrolysis reactor 3 is 150-450°C, and the material residence time within it is 30-80 minutes. The inner wall of the inner chamber of the low-temperature pyrolysis reactor 3 is equipped with multiple guide plates to guide the material forward. The material residence time can be adjusted by rotating them. The inner wall of the outer chamber is equipped with multiple guide vanes to guide the flue gas forward. The flue gas flow rate can be controlled by adjusting the opening of the guide vanes.

[0028] The medium-temperature pyrolysis reactor 4 consists of an inner chamber and an outer chamber, both of which are equipped with an inlet and an outlet. The operating temperature of the medium-temperature pyrolysis reactor 4 is 450-600°C, and the material pyrolysis time in this area is 20-40 minutes. The inner wall of the medium-temperature pyrolysis reactor 4 is equipped with multiple guide plates to guide the material forward. The material residence time can be adjusted by rotating the guide plates. The inner wall of the outer chamber is equipped with multiple guide vanes to guide the flue gas forward. The flue gas flow rate can be controlled by adjusting the opening of the guide vanes. The high-temperature pyrolysis reactor 5 consists of an inner chamber and an outer chamber, both of which are provided with an inlet and an outlet. The operating temperature of the high-temperature pyrolysis reactor 5 is 600-1000°C, and the material stays in this area for 10-30 minutes. Carbon dioxide gas with a purity of not less than 99% is introduced at a flow rate of 5-20 m 3 / h. The inner wall of the pyrolysis reactor 5 is equipped with multiple guide plates for forward material movement. Rotation adjusts the material residence time. The outer wall of the chamber is equipped with multiple guide vanes for forward flue gas flow. Adjusting the opening of the guide vanes controls the flue gas flow rate.

[0029] The dechlorination unit 9 includes an absorbent storage tank, a spiral absorbent feeding system, and a mixing reaction chamber. The dechlorination unit 9 uses dry calcium hydroxide powder as the absorbent. The absorbent storage tank is connected to the mixing reaction chamber via a pipeline. A nozzle is installed in the mixing reaction chamber to spray Ca(OH)2 into the pyrolysis gas for reaction. The mixing reaction chamber temperature is controlled at 200-300°C, with a residence time of 30-60 minutes, achieving a dechlorination efficiency exceeding 95%.

[0030] Combustion chamber 8 is a vertical cylindrical structure, equipped with a grate and ignition device. The operating temperature of combustion chamber 8 is 800-1200°C, and temperature monitoring and control are achieved through temperature sensors. Several temperature sensors are installed above combustion chamber 8 to monitor flue gas temperature, which is precisely controlled by a PLC control system.

[0031] The flue gas purifier 10 adopts a multi-stage bag dust collector and an activated carbon adsorber. The start and stop of each stage of the purifier can be adjusted according to the actual situation through the valve 12. The working temperature of the purifier is controlled at 150-200°C, and the wind speed is 5-10m / s. The heat exchanger 7 adopts a plate heat exchanger, and the heat exchange between cold water and hot air is achieved through the coordinated work of the first induced draft fan 6 and the first induced draft fan 11. The heat exchange area of the heat exchanger 7 is 50-100m 2 , the heat exchange efficiency is not less than 85%.

[0032] The system also includes an intelligent control system, including temperature sensors, flow meters, and online detectors for hydrogen chloride and hydrogen sulfide. The PLC control system enables precise control and automatic adjustment of temperatures in each zone, automatically optimizing various parameters based on real-time monitoring data. The control system also features remote monitoring capabilities, allowing users to view operating status and adjust parameters in real time via mobile devices.

[0033] according to Figure 1 As shown, the connection relationship between the components can be described as follows according to the flow paths of materials, gases, flue gas and carbon dioxide: Material flow path: Domestic waste enters dryer 2 from feeder 1 for drying. The dried material enters low-temperature pyrolysis reactor 3, medium-temperature pyrolysis reactor 4 and high-temperature pyrolysis reactor 5 in sequence for multi-stage pyrolysis reaction.

[0034] Gas Flow Path: The pyrolysis gas produced by the low-temperature pyrolysis reactor 3 and the medium-temperature pyrolysis reactor 4 enters the dechlorination unit 9 for dechlorination. After dechlorination, the pyrolysis gas enters the combustion chamber 8 for combustion, generating high-temperature flue gas. The flue gas enters the flue gas purifier 10 for purification. The synthesis gas produced by the high-temperature pyrolysis reactor 5 enters the heat exchanger 7 for heat exchange with cold water, generating hot water. After heat exchange, the synthesis gas enters the dryer 2, providing a heat source for drying the domestic waste.

[0035] Flue Gas Flow Path: The high-temperature flue gas generated in combustion chamber 8 undergoes heat exchange through heat exchanger 7. After heat exchange, the flue gas sequentially enters high-temperature pyrolysis reactor 5, medium-temperature pyrolysis reactor 4, and low-temperature pyrolysis reactor 3, providing heat for the pyrolysis reaction. The flue gas exiting low-temperature pyrolysis reactor 3 enters flue gas purifier 10 for purification.

[0036] Carbon dioxide flow path: Carbon dioxide is controlled by valve 12 and enters the high-temperature pyrolysis reactor 5 to participate in the gasification reaction.

[0037] Auxiliary Equipment Function: The first and second induced draft fans 6 and 11 guide the flow of gas within the system, ensuring that the gas flows between components according to the predetermined process. The solid residue produced by the low-temperature pyrolysis reactor 3 and the high-temperature pyrolysis reactor 5 is discharged from the system through the corresponding exhaust ports.

[0038] In the present invention, domestic waste is first dehydrated by the dryer 2, and then enters the low-temperature pyrolysis reactor 3, the medium-temperature pyrolysis reactor 4, and the high-temperature pyrolysis reactor 5 for pyrolysis and gasification reactions. The pyrolysis gas generated by the low and medium-temperature pyrolysis reactors passes through the dechlorination device 9 and enters the combustion chamber 8 to burn and produce high-temperature flue gas. The high-temperature flue gas enters the high, medium, and low-temperature pyrolysis reactors in turn to provide the heat source required for the pyrolysis reaction, and then enters the flue gas purifier 10 to meet the emission standards. The high-temperature pyrolysis reactor 5 introduces carbon dioxide and medium-temperature char for gasification reaction. The high-temperature CO, CH4 and other high-quality synthesis gases generated after the reaction enter the heat exchanger 7 for heat exchange with cold water to produce hot water for external use. After the synthesis gas after heat exchange enters the dryer 2 to dry the domestic waste, high-quality synthesis gas at low temperature can be obtained. The present invention adopts the high-temperature flue gas indirect heat exchange method to carry out multi-stage pyrolysis reaction on domestic waste, realizes the adjustment of the reaction temperature and reaction time of each reaction zone, and ensures the full decomposition and resource utilization of complex domestic waste components. The present invention does not require an external heat source, but relies on the heat provided by the domestic waste itself to carry out pyrolysis and gasification reactions. It can improve the pyrolysis efficiency and energy self-sufficiency rate of domestic waste, effectively control the generation and release of harmful substances such as chlorine, and take into account both environmental protection and economy. It is suitable for building a green and low-carbon domestic waste resource treatment system and has broad industrial application prospects.

[0039] Example 1 Domestic waste is fed into the dryer evenly at a rate of 50 kg / h through a feeder for drying.

[0040] In the dryer, the raw materials are preliminarily dried. The humidity of the dried domestic waste can be controlled at around 10% by adjusting the temperature and flow of the synthesis gas. The dried domestic waste is then introduced into the low-temperature zone of the pyrolysis gasification reactor.

[0041] The low temperature zone is set at 400 o C. The material is pyrolyzed in the low temperature zone for 1 hour. During this process, the low temperature pyrolysis gas is passed into the dechlorination device, and the low temperature carbon material after pyrolysis in the low temperature zone is passed into the medium temperature zone.

[0042] The temperature in the medium temperature zone is set at 500 o C. The material is pyrolyzed in the medium temperature zone for 30 minutes, and the generated medium temperature pyrolysis gas is introduced into the dechlorination device. The medium temperature carbon material after pyrolysis in the medium temperature zone is introduced into the high temperature zone.

[0043] After the pyrolysis gas is dechlorinated by spraying Ca(OH)2 in the dechlorination device, the dechlorinated pyrolysis gas enters the combustion chamber for combustion, generating high-temperature flue gas.

[0044] The combustion chamber is fed with air of excess air coefficient 1.2, and the high temperature flue gas produced can be temperature-controlled by introducing cold air to control the flue gas temperature at 1100 oC, and then respectively exchange heat with the materials in the high temperature zone, medium temperature zone and low temperature zone. Finally, the flue gas enters the purification system and is discharged after purification.

[0045] The high temperature zone is set at 900 o C, control the CO2 flow rate at 10m 3 / h, to ensure that the gasification reaction is fully carried out, the material is gasified in this area for 30 minutes, and the high-temperature gasification gas generated in this process is introduced into the heat exchanger for heat exchange with cold water, outputting usable hot water and at the same time reducing the temperature of the gasification synthesis gas to 200 o C.

[0046] The cooled gasified synthesis gas is sent to the dryer for heat exchange and cooling with domestic waste, and finally a low-temperature, high-quality synthesis gas containing CO, CH4, etc. is obtained.

[0047] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. When a component is referred to as being "fixed to" another component, it can be directly on the other component or there can also be an intermediate component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there can be an intermediate component at the same time. When a component is considered to be "set on" another component, it can be directly set on the other component or there can be an intermediate component at the same time.

[0049] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0050] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0052] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in this industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A system for producing high-quality synthesis gas from domestic waste and carbon dioxide, characterized in that: include: A feeder (1), a dryer (2), a low-temperature pyrolysis reactor (3), a medium-temperature pyrolysis reactor (4), and a high-temperature pyrolysis reactor (5) connected in sequence; The pyrolysis gas outlets of the low-temperature pyrolysis reactor (3) and the medium-temperature pyrolysis reactor (4) are connected to the dechlorination device (9) and the combustion chamber (8) in sequence; The flue gas outlet of the combustion chamber (8) is connected in sequence to the flue gas pipelines of the high-temperature pyrolysis reactor (5), the medium-temperature pyrolysis reactor (4), the low-temperature pyrolysis reactor (3), and the flue gas purifier (10); The synthesis gas outlet of the high-temperature pyrolysis reactor (5) is connected to the heat exchanger (7) and the dryer (2) in sequence.

2. The system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to claim 1, characterized in that: The dryer (2), low-temperature pyrolysis reactor (3), medium-temperature pyrolysis reactor (4), and high-temperature pyrolysis reactor (5) all adopt a double-chamber structure, including an inner chamber and an outer chamber. The inner chamber is provided with a material guide plate, and the outer chamber is provided with a flue gas guide vane. Each reactor forms a flue gas circulation loop with the combustion chamber (8) through a heat exchanger (7).

3. The system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to claim 1, characterized in that: The operating temperature of the dryer (2) is 105-150°C; The low-temperature pyrolysis reactor (3) has an operating temperature of 150 to 450°C and a material residence time of 30 to 80 minutes; The medium-temperature pyrolysis reactor (4) has an operating temperature of 450 to 600°C and a material residence time of 20 to 40 minutes; The high-temperature pyrolysis reactor (5) has an operating temperature of 600 to 1000° C., and a material residence time of 10 to 30 minutes.

4. The system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to claim 1, characterized in that: A first induced draft fan (6) is provided on the pipeline between the heat exchanger (7) and the dryer (2).

5. The system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to claim 1, characterized in that: A valve (12) is provided on the carbon dioxide inlet pipeline of the high-temperature pyrolysis reactor (5).

6. The system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to claim 1, characterized in that: A second induced draft fan (11) is provided on the outlet pipeline of the flue gas purifier (10).

7. The system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to claim 1, characterized in that: The feed port of the dryer (2) is provided with a sealing device.

8. The system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to claim 1, characterized in that: The dryer (2), low-temperature pyrolysis reactor (3), medium-temperature pyrolysis reactor (4), and high-temperature pyrolysis reactor (5) are all equipped with a PLC control unit and an automatic adjustment module, and closed-loop control of the temperature, flue gas flow rate, and material residence time of each zone is achieved through temperature sensors, flow meters, and online detectors for hydrogen chloride and hydrogen sulfide.

9. The system for producing high-quality synthesis gas from domestic waste and carbon dioxide according to claim 1, characterized in that: The dechlorination device (9) is provided with an absorbent spiral feeding system and a mixing reaction chamber, and uses calcium hydroxide dry powder as the absorbent.

10. A method for producing high-quality synthesis gas from domestic waste and carbon dioxide, using the system according to any one of claims 1 to 9, characterized in that: The following steps are involved: Domestic waste enters the dryer (2) through the feeder (1), and is dehydrated at 105-150°C to obtain dry material; The dried material is sequentially fed into a low-temperature pyrolysis reactor (3), a medium-temperature pyrolysis reactor (4), and a high-temperature pyrolysis reactor (5) to undergo a multi-stage pyrolysis and gasification reaction; The pyrolysis gas generated by the multi-stage pyrolysis is dechlorinated by the dechlorination device (9) and then enters the combustion chamber (8) for combustion. The high-temperature flue gas generated by the combustion flows through the high-temperature pyrolysis reactor (5), the medium-temperature pyrolysis reactor (4), and the low-temperature pyrolysis reactor (3) in sequence. After the heat required for pyrolysis is provided by indirect heat exchange, the flue gas is treated by the flue gas purifier (10) and then discharged. Carbon dioxide is introduced into the high-temperature pyrolysis reactor (5) to react with the medium-temperature charcoal to generate synthesis gas. The synthesis gas is cooled by the heat exchanger (7) and then enters the dryer (2) to dry the domestic waste, and finally outputs high-quality synthesis gas.

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