Municipal solid waste treatment system, treatment process, and methanol production system for methanol production.

Abstract

The present application relates to solid waste catalytic treatment technical field, specifically relates to a kind of for preparing methanol domestic waste treatment system, treatment process and preparation methanol system.The domestic waste treatment system includes: screw feeder and pyrolysis device, wherein screw feeder has first mixed material inlet, recovered catalyst inlet and second mixed material outlet, and first mixed material inlet is used to input domestic waste and fresh catalyst;Pyrolysis device has second mixed material inlet, recovered catalyst outlet, second mixed material inlet is connected with second mixed material outlet, and recovered catalyst outlet is connected with recovered catalyst inlet.The waste catalyst after catalytic pyrolysis reaction of domestic waste is used for in-situ ash melting point regulation of pyrolysis carbon in the present application, the regulation of ash melting point is realized, the sorting separation step of waste catalyst is avoided simultaneously, and the gasification product obtained after treatment of the present application includes carbon monoxide and hydrogen, and can be used for raw material gas of methanol synthesis.

Description

Technical Field

[0001] This invention relates to the field of solid waste catalytic treatment technology, and more specifically, to a municipal solid waste treatment system, treatment process, and methanol preparation system for methanol production. Background Technology

[0002] Due to its complex composition, high water content, and low calorific value, municipal solid waste presents a significant challenge in achieving its reduction, harmlessness, and resource utilization. Currently, the main methods for treating municipal solid waste include sanitary landfill, incineration, composting, and pyrolysis. Incineration is the most widely used method, using high-temperature combustion to fully oxidize combustible components and recover waste heat for power generation or steam production. However, incineration typically produces acidic gases, heavy metals, and especially dioxins, which to some extent restricts the development of the incineration industry. In recent years, pyrolysis gasification technology has emerged in the waste treatment field due to its advantages such as strong raw material adaptability, no dioxin production, and low investment. Furthermore, the products obtained from waste pyrolysis gasification can be used in the production of methanol.

[0003] Waste pyrolysis gasification technology refers to the process of pyrolysis and gasification of organic components in municipal solid waste under anaerobic or gasifying agent conditions, generating solid carbon, combustible gas, and pyrolysis oil. The complex composition of municipal solid waste makes direct gasification difficult, leading to increased attention on pyrolysis-plus-gasification methods in recent years. This method primarily converts municipal solid waste into relatively uniform pyrolysis char through pyrolysis, which is then used in a gasifier to produce syngas. This significantly reduces the difficulty of waste gasification. Among pyrolysis-plus-gasification methods, coal-water slurry gasification technology, with its simple furnace design and easy feed control, has been widely used as a raw material for syngas production. Coal-water slurry gasification typically uses a fluidized bed furnace and liquid ash discharge. This requires the melting temperature of the gasified ash to be lower than the gasification temperature; otherwise, energy consumption will increase, potentially affecting the stable operation of the gasifier. However, existing municipal solid waste pyrolysis processes lack effective technical means to control the ash melting temperature, thus failing to guarantee the operational stability of the gasifier. In addition, existing municipal solid waste pyrolysis processes also face the problem of difficulties in catalyst recycling. Summary of the Invention

[0004] In view of this, the present invention aims to at least partially solve one of the technical problems in the related art. To this end, the present invention provides a municipal solid waste treatment system and process that can effectively control the ash melting temperature of municipal solid waste and can directly recover and reuse spent catalysts.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] According to one aspect of this application, an embodiment of this application provides a municipal solid waste treatment system, the treatment system comprising:

[0007] The screw feeder has a first mixed material inlet, a recycled catalyst inlet, and a second mixed material outlet, wherein the first mixed material inlet is used to input municipal solid waste and fresh catalyst;

[0008] A pyrolysis apparatus having a second mixture inlet and a recovered catalyst outlet, the second mixture inlet being connected to the second mixture outlet and the recovered catalyst outlet being connected to the recovered catalyst inlet.

[0009] In addition, the municipal solid waste treatment system according to this application may also have the following additional technical features:

[0010] The municipal solid waste treatment system also includes a crusher and a drying device. The drying device has a municipal solid waste inlet, a fresh catalyst inlet, and a first mixed material outlet, with the first mixed material inlet connected to the first mixed material outlet. The outlet of the crusher is connected to the municipal solid waste inlet.

[0011] In some embodiments, the municipal solid waste treatment system further includes a mixing silo located between the drying device and the screw feeder, wherein the first mixed material outlet is connected to the inlet of the mixing silo, and the outlet of the mixing silo is connected to the first mixed material inlet.

[0012] In some embodiments, the municipal solid waste treatment system further includes a heat exchanger, a burner, and a pulping device. The pyrolysis device also has a pyrolysis liquid product outlet and a heating inlet. The pulping device has a pyrolysis liquid inlet. The pyrolysis liquid product outlet is connected to the inlet of the heat exchanger. The first outlet of the heat exchanger is connected to the pyrolysis liquid inlet. The second outlet of the heat exchanger is connected to the inlet of the burner. The outlet of the burner is connected to the heating inlet.

[0013] In some embodiments, the pyrolysis apparatus further includes a pyrolysis gas outlet connected to the gas inlet of the drying apparatus.

[0014] In some embodiments, the drying apparatus includes a rotary kiln dryer.

[0015] In some embodiments, the pyrolysis apparatus includes a rotary kiln pyrolysis reactor.

[0016] In some embodiments, the pulping apparatus also has a solids inlet connected to the recovered catalyst outlet.

[0017] In some embodiments, the pulping device also has an outlet for the material to be gasified; the municipal solid waste treatment system also includes a gasification device having an inlet for the material to be gasified, the inlet being connected to the outlet for the material to be gasified.

[0018] According to another aspect of this application, embodiments of this application provide a municipal solid waste treatment process for preparing methanol, the process comprising the following steps:

[0019] The mixture containing municipal solid waste to be treated and fresh catalyst is fed into a screw feeder for mixing to obtain the mixture.

[0020] The mixture is fed into a pyrolysis device for pyrolysis treatment to obtain pyrolytic solid material and pyrolytic liquid material;

[0021] The pyrolysis solid material includes a mixture of recovered catalyst and pyrolysis carbon. At least a portion of the pyrolysis solid material is returned to the screw feeder to participate in the reaction again, and at least a portion of the pyrolysis liquid material is supplied to a pulping device for pulping treatment.

[0022] In some embodiments, the processing technology includes the following steps:

[0023] The municipal solid waste to be treated and the fresh catalyst are fed into a drying device for drying, and the municipal solid waste to be treated and the fresh catalyst are initially mixed in the drying device to obtain a first mixture.

[0024] The first mixture is fed to a screw feeder for secondary mixing to obtain a second mixture;

[0025] The second mixture is fed into a pyrolysis device for pyrolysis treatment to obtain pyrolysis solid material and pyrolysis liquid material;

[0026] The pyrolysis solid material includes a mixture of recovered catalyst and pyrolysis carbon. At least a portion of the pyrolysis solid material is returned to the screw feeder to participate in the reaction again, and at least a portion of the pyrolysis liquid material is supplied to a pulping device for pulping treatment.

[0027] In some of the embodiments, the processing technology satisfies at least one of the following features (1) to (5): (1) the temperature of the drying treatment is 120℃ to 150℃; (2) the mass of the fresh catalyst is 1% to 10% of the mass of the municipal solid waste to be treated; (3) the fresh catalyst includes a molecular sieve catalyst; (4) the temperature of the pyrolysis treatment is 350℃ to 450℃; (5) the total mass of the pyrolysis solid material obtained by the pyrolysis treatment is m1, and the mass of the pyrolysis solid material returned to the screw feeder is m2, wherein m1 and m2 satisfy: m2 = (10% to 30%) * m1.

[0028] In some of these embodiments, the household waste to be treated is crushed waste, and the particle size of the crushed waste is ≤30mm.

[0029] In some embodiments, the first mixture is fed to the screw feeder after passing through a mixing bin.

[0030] In some embodiments, a portion of the pyrolysis solids is returned to the screw feeder for further reaction, while the remainder is fed to a pulping unit for pulping. The pulp obtained from the pulping unit is then fed to a gasification unit for gasification.

[0031] In some embodiments, the pyrolysis liquid material is supplied to a pulping device for pulping after heat exchange via a heat exchanger.

[0032] In some embodiments, a portion of the pyrolysis gas obtained from the pyrolysis treatment is supplied to a burner after heat exchange via a heat exchanger, and the material after combustion in the burner is supplied to the pyrolysis device for heating the pyrolysis device.

[0033] In some embodiments, a portion of the pyrolysis gaseous material obtained from the pyrolysis treatment is supplied to a drying device for drying.

[0034] According to another aspect of this application, an embodiment of this application provides a methanol production system for co-gasification of municipal solid waste. The methanol production system includes the aforementioned municipal solid waste treatment system and a methanol synthesis device; wherein the outlet of the gasification device in the municipal solid waste treatment system is connected to the inlet of the methanol synthesis device.

[0035] Implementing the technical solution of the present invention has at least the following beneficial effects:

[0036] In this embodiment, the provided municipal solid waste treatment system and process uses a screw feeder to mix and transport the mixed materials. The mixed materials then enter a pyrolysis unit for in-situ catalytic pyrolysis. After pyrolysis, the resulting pyrolysis solid material includes a mixture of recovered catalyst and pyrolysis carbon. At least a portion of this pyrolysis solid material is returned to the screw feeder for further reaction. Therefore, this application directly returns the pyrolysis solid material containing recovered catalyst (waste catalyst) and pyrolysis carbon to the screw feeder for further reaction. In other words, the waste catalyst after the catalytic pyrolysis of municipal solid waste is used for in-situ ash melting point control of pyrolysis carbon. The ash melting point is controlled through the phase transformation reaction between the waste catalyst and the ash in the pyrolysis carbon at high temperature. This avoids the sorting and separation steps of deactivated catalyst, reduces catalyst costs, and fully utilizes the catalyst's value.

[0037] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0038] Figure 1 The diagram shown is a schematic diagram of a municipal solid waste treatment system provided in an embodiment of the present invention.

[0039] Figure 2 The diagram shown is a schematic diagram of another municipal solid waste treatment system provided in an embodiment of the present invention.

[0040] Figure 3 The figure shown is a ternary phase diagram of the chemical composition of municipal solid waste ash calculated by Factsage according to an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 10-Crusher;

[0043] 20-Drying unit; 201-Domestic waste inlet; 202-Fresh catalyst inlet; 203-First mixture outlet; 204-Gas inlet;

[0044] 30 - Mixing bin;

[0045] 40 - Screw feeder; 401 - First mixture inlet; 402 - Recovered catalyst inlet; 403 - Second mixture outlet;

[0046] 50 - Pyrolysis unit; 501 - Second mixture inlet; 502 - Catalyst recovery outlet; 503 - Pyrolysis liquid product outlet; 504 - Heating inlet; 505 - Pyrolysis gas outlet;

[0047] 60 - Heat exchanger; 601 - First outlet; 602 - Second outlet;

[0048] 70 - Burner;

[0049] 80 - Pulping unit; 801 - Pyrolysis liquid inlet; 802 - Solid inlet; 803 - Material to be gasified outlet;

[0050] 90 - Gasification device; 901 - Inlet for material to be gasified. Detailed Implementation

[0051] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0052] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges or individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] As analyzed in the background section, current coal-water slurry gasification technology requires the melting temperature of the gasification ash to be lower than the gasification temperature; otherwise, it will increase energy consumption and even affect the stable operation of the gasifier. Currently, municipal solid waste can be mainly divided into kitchen waste, paper, wood and bamboo, rubber and plastic, and textiles. Due to the high proportion of paper in municipal solid waste, and the addition of bleaching agents during paper production, as well as the addition of calcium carbonate to rubber and plastics to improve product performance, the calcium content in municipal solid waste ash is very high, reaching approximately 50%. Calcium oxide (CaO), as an alkaline oxide, can both lower and raise the ash melting temperature. When the calcium content is at a low mass fraction, calcium has a positive effect on regulating the ash melting temperature; however, when the calcium content is high, it leads to a rapid increase in the ash melting temperature. Currently, the low silicon and aluminum content and high calcium content of municipal solid waste ash significantly increase its ash melting temperature. Therefore, how to efficiently and easily control the ash melting point of municipal solid waste has become a key factor and a difficult problem in ensuring the stable operation of the waste gasification process.

[0055] Furthermore, the quality of oil produced during current waste pyrolysis processes is generally poor, especially the formation of tar, which can lead to wall blockage and other problems affecting the normal operation of the pyrolysis furnace. Common methods for treating tar include high-temperature cracking or water washing, but these methods cannot avoid problems such as high energy consumption, low efficiency, or secondary pollution from wastewater. Catalytic pyrolysis has certain applications in biomass pyrolysis reactions because it can reduce tar production and improve oil quality to some extent. Catalytic pyrolysis refers to the directional control of pyrolysis products under the action of a catalyst. It is generally divided into in-situ catalysis and ex-situ catalysis. In-situ catalysis directly mixes the catalyst with the feedstock for the pyrolysis reaction, which has the advantages of sufficient contact and simple process. However, after the reaction, the catalyst is mixed with the pyrolysis char, and the problem of sorting and recovering the deactivated catalyst arises. Currently, catalyst sorting is usually done by sieving, water washing, or filtration, but these methods inevitably increase the complexity of the in-situ catalytic pyrolysis process. Therefore, finding a simple technology for sorting or utilizing spent catalysts after catalytic pyrolysis has become one of the problems that needs to be solved in catalytic pyrolysis technology.

[0056] Furthermore, methanol is an important chemical raw material. It can be used as a gasoline additive, to synthesize gasoline, to synthesize acetic acid and acetic anhydride, or in methanol engines. With the continuous expansion and development of methanol applications, the market for methanol is becoming increasingly broad. Therefore, this invention treats municipal solid waste and applies the resulting gasification products, such as gasified coal gas rich in carbon monoxide and hydrogen, to methanol production. Using this as a raw material to produce methanol is beneficial for realizing the resource utilization of waste pyrolysis char.

[0057] In view of this, this invention addresses two main technical problems currently faced by in-situ catalytic pyrolysis processes for municipal solid waste: the control of the ash melting point of municipal solid waste and the sorting, recycling, and reuse of spent catalysts. This invention provides a municipal solid waste treatment system and process for methanol production, as well as a system for the co-processing of municipal solid waste with biomass gasification to produce methanol. This system and process are methods for the co-processing of spent catalytic pyrolysis catalysts and the control of the ash melting temperature of municipal solid waste. It can solve the problems of sorting and separating deactivated catalysts and the high melting point of pyrolysis ash during the pyrolysis and gasification process of municipal solid waste. The gasification products obtained after treatment can also be used in methanol production, achieving resource utilization. The following is a detailed description of this application.

[0058] Please see Figures 1 to 2 As shown, in some embodiments, a municipal solid waste treatment system is provided, which includes a drying device 20, a screw feeder 40, a pyrolysis device 50, and a pulping device 80.

[0059] The drying unit 20 is used to dry the municipal solid waste and fresh catalyst, and the two materials can be initially mixed within the drying unit 20. The screw feeder 40 is used to further mix the initially mixed municipal solid waste and fresh catalyst. The screw feeder 40 also serves as a material conveyor, transporting the well-mixed mixture of municipal solid waste and fresh catalyst to the pyrolysis unit 50. The pyrolysis unit 50 is used to pyrolyze the municipal solid waste under the action of the catalyst. The pulping unit 80 is used to pulp the material obtained after pyrolysis.

[0060] In this application, a portion of the pyrolysis solid material obtained after pyrolysis treatment, namely a portion containing recycled catalyst (waste catalyst) and pyrolysis carbon, is directly returned to the screw feeder 40 for further reaction. This not only achieves direct recycling of the waste catalyst without the need for sorting and screening, thus reducing catalyst costs, but also allows for the control of the ash melting temperature of municipal solid waste through the addition of the waste catalyst, fully utilizing the catalyst's value. Simultaneously, it solves the problems of sorting and separating deactivated catalyst (waste catalyst) and the high melting point of pyrolysis carbon ash during the pyrolysis and gasification process of municipal solid waste. In detail:

[0061] (1) Current biomass catalytic pyrolysis can improve product quality. Commonly used catalysts include activated carbon, metal oxides, and molecular sieves. These catalysts are usually in granular or powder form. During in-situ catalytic pyrolysis, the catalyst is uniformly mixed with the material. After pyrolysis, the catalyst is distributed in the pyrolyzed carbon, making it difficult to recycle the waste catalyst. Therefore, it is necessary to solve the problem of difficult recycling of waste catalyst. (2) Currently, the liquid ash discharge of the fluidized bed gasifier requires the gasification ash melting temperature to be lower than the gasification temperature. However, due to the high calcium content in the waste, the ash melting point of the waste is usually greater than 1500℃, which is much higher than the commonly used operating temperature of 1300℃ for fluidized bed gasifiers. If the equipment is to operate stably, the gasifier temperature needs to be increased, which greatly increases the gasification energy consumption. At the same time, the characteristics of low silicon and aluminum content and high calcium content in municipal solid waste (as shown in Table 1 below) make it impossible to control the ash melting temperature like adding calcium to coal ash. Therefore, it is necessary to find a simple and effective method for controlling the ash melting temperature of municipal solid waste, which is crucial for the operational stability of the gasifier. (3) For some high-calcium coals, quartz and other substances are often added to control the ash melting point. However, the calorific value of municipal solid waste is much lower than that of coal. Even after pyrolysis, the calorific value of the pyrolyzed char is usually low. If SiO2 (such as quartz) is added during the gasification process to control the ash melting point, the calorific value of the waste pyrolyzed char will be further reduced, which may lead to difficulties in the operation of the gasifier. Therefore, it is necessary to find a flux and control process that can control the ash melting point of waste without having a significant impact on the calorific value of the raw materials.

[0062] Based on the aforementioned problems, the inventors of this application, after extensive research, proposed a method for controlling the ash melting point of municipal solid waste using spent catalysts. Based on this method, they proposed a process system and method for synergistically treating spent catalysts from catalytic pyrolysis and controlling the ash melting temperature of municipal solid waste. This method primarily addresses the issues of separating deactivated catalysts during the pyrolysis and gasification process of municipal solid waste and the high ash melting point of pyrolyzed char. This approach of controlling the ash melting point of municipal solid waste using spent catalysts involves using the spent catalysts from the catalytic pyrolysis reaction of municipal solid waste for in-situ ash melting point control of pyrolyzed char. Ash melting point control is achieved through a high-temperature phase transformation reaction between the spent catalyst and the ash in the pyrolyzed char. This avoids the separation steps of deactivated catalysts, reduces catalyst costs, and fully utilizes the catalyst's value.

[0063] The principle of using spent catalysts to regulate the ash melting temperature of municipal solid waste lies in calculating the ternary phase diagram based on the chemical composition of the municipal solid waste ash using Factsage. Figure 3 It is known that by normalizing silicon dioxide (SiO2), aluminum oxide (Al2O3), and calcium oxide (CaO) as the main components of ash, only when the mass fraction of CaO in the ash is at a certain value can the melting temperature be reduced. However, the CaO content in municipal solid waste is excessive, so other metal fluxing agents should be added to reduce the CaO content. Since the main components of molecular sieve catalysts are SiO2 and a small amount of Al2O3, the molecular sieves do not change their composition after catalytic pyrolysis deactivation. Thus, considering the characteristics of materials such as municipal solid waste ash, which have high calcium content and low silicon and aluminum content, adding an appropriate amount of waste molecular sieve fluxing agent to the ash causes the molecular sieve framework structure to collapse during high-temperature gasification. The main component, SiO2, reacts chemically with the excess CaO in the ash, lowering the ash melting point and solving the gasification problem caused by the high melting point of municipal solid waste ash.

[0064] It should be understood that Factsage software is widely used to calculate multi-element phase diagrams under different constraints, and has been extensively studied in the areas of ash melting point and crystal composition characteristics of multi-element coal ash. The model in this application is a ternary phase diagram model constructed after simplification and normalization based on the elemental composition characteristics of actual municipal solid waste ash. Furthermore, the relationship between the proportions of SiO2, Al2O3, and CaO and the ash melting point is generally agreed upon in the relevant field.

[0065] Furthermore, in in-situ catalytic pyrolysis, the uniformity of the mixing between the catalyst and the material usually has a significant impact on the catalytic effect. This application, through the installation of the drying device 20 and the screw feeder 40, not only serves the functions of drying and feeding, but also ensures thorough mixing of the municipal solid waste to be treated with the catalyst. This eliminates the need for a separate mixing device, simplifies the process, and avoids the impact of uneven mixing between the catalyst and the material on the catalytic effect during in-situ catalytic pyrolysis.

[0066] In this application, the municipal solid waste treatment system provided can be applied to methanol production, such as in the co-gasification of municipal solid waste with biomass to produce methanol, so as to realize resource utilization and reduce methanol production costs.

[0067] It should be understood that methanol production requires syngas, which is carbon monoxide (CO) + hydrogen (H2). This application uses municipal solid waste as raw material, converting it into CO and H2 through a series of chemical treatment processes. For example, in the gasification unit of a waste treatment system, pyrolytic carbon and pyrolysis liquid are used as raw materials. After gasification, syngas composed of CO and H2 is obtained. This syngas can then be used to produce methanol after purification and compression. The specific synthesis process and apparatus for methanol are relatively mature in the prior art, and this application does not limit them. This application mainly provides syngas composed of CO and H2 that can be used to produce methanol.

[0068] The following section provides a more detailed description of the specific equipment and processing conditions of this municipal solid waste treatment system and process.

[0069] In some specific embodiments, the municipal solid waste treatment system also includes a crusher 10, a mixing silo 30, a heat exchanger 60, a burner 70, and a gasification device 90. That is, the municipal solid waste treatment system may include a crusher 10, a drying device 20, a mixing silo 30, a screw feeder 40, a pyrolysis device 50, a heat exchanger 60, a burner 70, a pulping device 80, and a gasification device 90.

[0070] In this municipal solid waste treatment system, the crusher 10 is used to crush the municipal solid waste to be processed, thereby improving the calorific value and homogeneity of the waste material. The crusher 10 has an inlet and an outlet. The municipal solid waste to be processed is fed into the crusher 10 from the inlet, and the crusher 10 is used to crush the waste particles to the target particle size, such as crushing the waste particles to below 30mm, thereby improving the calorific value and homogeneity of the waste material.

[0071] Optionally, the household waste can be sorted before being fed to the crusher 10. For example, the household waste that has been sorted to remove inorganic materials such as glass and metal can be fed into the crusher 10.

[0072] It should be noted that this application does not impose any specific restrictions on the type of household waste. As an example, the household waste can be raw waste from which inorganic matter has been removed, wherein the mass content of paper, rubber and plastic, textiles, and wood and bamboo is approximately in the range of 20-25%: 25-30%: 25-30%: 15-20%.

[0073] In this municipal solid waste treatment system, the drying device 20 can be used to dry the municipal solid waste and fresh catalyst to be treated. Simultaneously, the municipal solid waste and fresh catalyst can be initially mixed within the drying device 20. The drying device 20 has a municipal solid waste inlet 201, a fresh catalyst inlet 202, and a first mixed material outlet 203. The outlet of the crusher 10 is connected to the municipal solid waste inlet 201 of the drying device 20, and the fresh catalyst inlet 202 can be used to add fresh catalyst. Optionally, the municipal solid waste inlet 201 and the fresh catalyst inlet 202 can be the same inlet, or they can be two inlets. For example, the fresh catalyst inlet 202 can be located on a pipe connected to the municipal solid waste inlet 201; this application does not limit this.

[0074] It should be understood that a fresh catalyst refers to a catalyst that has not participated in a reaction.

[0075] Optionally, the drying device 20 adopts a rotary kiln dryer. By using a rotary kiln dryer, i.e., a drying rotary kiln, both material drying and material mixing can be achieved.

[0076] It should be noted that this application does not limit the specific structure or model of the rotary kiln dryer. Its specific structure or form can refer to the relevant prior art. As long as it is rotary kiln type and can be used for drying and mixing, it does not limit the purpose of this application.

[0077] Therefore, the municipal solid waste material crushed by the crusher 10 can be dried together with fresh catalyst in a rotary dryer. The fresh catalyst can be in powder or granular form. In this way, under high temperature and furnace rotation, some of the moisture in the waste can be removed and the catalyst and municipal solid waste material can be initially mixed. The mixture falls into the mixing bin 30 through the first mixing outlet 203 of the drying device 20.

[0078] Optionally, the drying temperature for the drying process is 120℃~150℃.

[0079] Optionally, the mass of the fresh catalyst is 1% to 10% of the mass of the municipal solid waste to be treated; that is, the mass ratio of the fresh catalyst to the municipal solid waste to be treated is 1% to 10%. Preferably, the mass of the fresh catalyst is about 5% of the mass of the municipal solid waste to be treated.

[0080] Optionally, the fresh catalyst used in this application can be a molecular sieve catalyst, such as a ZSM-5 molecular sieve catalyst or a USY molecular sieve catalyst.

[0081] In this municipal solid waste treatment system, the mixing bin 30 is located between the drying device 20 and the screw feeder 40. The mixing bin 30 has an inlet and an outlet. The first mixing material outlet 203 of the drying device 20 is connected to the inlet of the mixing bin 30, and the outlet of the mixing bin 30 is connected to the first mixing material inlet 401 of the screw feeder 40.

[0082] By setting up a mixing bin 30 between the drying device 20 and the screw feeder 40, the mixing bin 30 can be used to temporarily store or transfer the mixture obtained after mixing by the drying device 20, which helps to improve the flexibility of the entire system and facilitates operation.

[0083] Optionally, in some cases, the mixing bin 30 may not be provided. For example, the first mixing material outlet 203 of the drying device 20 may be directly connected to the first mixing material inlet 401 of the screw feeder 40.

[0084] The specific structural form of the mixing silo 30 can be selected and set according to the actual situation, and this application does not limit it.

[0085] In this municipal solid waste treatment system, the screw feeder 40 has a first mixed material inlet 401, a recovered catalyst inlet 402, and a second mixed material outlet 403. The first mixed material inlet 401 of the screw feeder 40 is connected to the first mixed material outlet 203 of the drying device 20, or the first mixed material inlet 401 of the screw feeder 40 is connected to the outlet of the mixing bin 30. The recovered catalyst inlet 402 can be connected to the recovered catalyst outlet 502 of the pyrolysis device 50, and the second mixed material outlet 403 can be connected to the second mixed material inlet 501 of the pyrolysis device 50. Optionally, the first mixed material inlet 401 and the recovered catalyst inlet 402 can be the same inlet, or they can be two inlets; this application does not limit this.

[0086] The screw feeder 40 can serve both as a material conveyor and as a material mixer. Specifically, the catalyst (including fresh and recycled catalyst) and waste materials can be further mixed using the screw feeder 40. Simultaneously, the screw feeder 40 can also convey the fully mixed material to the pyrolysis unit 50.

[0087] In this application, the pyrolysis solid material containing the recovered catalyst obtained after pyrolysis in the pyrolysis unit 50 can be directly returned to the screw feeder 40 for further reaction, without having to be returned to the drying unit 20. This saves energy and simplifies the process.

[0088] Therefore, in the in-situ catalytic pyrolysis process, the uniformity of the mixture between the catalyst and the material usually has a significant impact on the catalytic effect. This application, through the installation of the drying device 20 and the screw feeder 40, not only serves to dry and transport the material, but also achieves thorough mixing of the municipal solid waste to be treated with the catalyst, eliminating the need for a separate mixing device, simplifying the process, and reducing equipment costs.

[0089] In this municipal solid waste treatment system, the pyrolysis device 50 has a second mixed material inlet 501, a catalyst recovery outlet 502, and a pyrolysis liquid product outlet 503. Furthermore, the pyrolysis device 50 also has a heating inlet 504 and a pyrolysis gas outlet 505.

[0090] In this municipal solid waste treatment system, heat exchanger 60 has an inlet, a first outlet 601, and a second outlet 602. Burner 70 has an inlet and an outlet.

[0091] In this municipal solid waste treatment system, the drying device 20 can also have a gas outlet.

[0092] Therefore, the second mixing material inlet 501 of the pyrolysis device 50 is connected to the second mixing material outlet 403 of the screw feeder 40; the recovered catalyst outlet 502 (also called the pyrolysis solid material outlet) of the pyrolysis device 50 is connected to the recovered catalyst inlet 402 of the screw feeder 40, and the recovered catalyst outlet 502 of the pyrolysis device 50 can also be connected to the solid inlet 802 of the pulping device 80. The pyrolysis liquid product outlet 503 of the pyrolysis device 50 is connected to the inlet of the heat exchanger 60, or the pyrolysis liquid product outlet 503 of the pyrolysis device 50 is connected to the pyrolysis liquid inlet 801 of the pulping device 80, the first outlet 601 of the heat exchanger 60 is connected to the pyrolysis liquid inlet 801 of the pulping device 80, the second outlet 602 of the heat exchanger 60 is connected to the inlet of the burner 70, and the outlet of the burner 70 is connected to the heating inlet 504 of the pyrolysis device 50. The pyrolysis gas outlet 505 of the pyrolysis device 50 is connected to the gas inlet 204 of the drying device 20.

[0093] Optionally, the pyrolysis unit 50 adopts a rotary kiln pyrolysis reactor.

[0094] In this application, the mixture after being mixed by the screw feeder 40 is fed into the pyrolysis unit 50. If fed into a rotary kiln pyrolysis reactor for anaerobic pyrolysis, the rotation of the kiln further enhances the uniformity of mixing between the waste material and the catalyst, allowing the catalyst to fully exert its catalytic effect. In the pyrolysis unit 50, the anaerobic pyrolysis reaction, relying on the catalytic effect of the catalyst, refers to the thermochemical transformation process of the waste material in an oxygen-free environment. The entire reaction process is relatively complex, typically including thermal cracking, polycondensation, dehydrogenation, and hydrogenation. Furthermore, due to the addition of the catalyst, catalytic cracking and shape-selective catalysis reactions may also occur during the pyrolysis process, ultimately converting the raw materials into small-molecule hydrocarbons, carbon monoxide, carbon dioxide, coke, and other substances.

[0095] Optionally, the pyrolysis temperature is 350℃ to 450℃. By controlling the pyrolysis temperature within this range, a higher pyrolysis char yield can be obtained.

[0096] After the pyrolysis reaction is completed, pyrolysis solid products (pyrolysis solid materials), pyrolysis liquid products (pyrolysis liquid materials), and pyrolysis gaseous products are obtained. The pyrolysis solid products mainly include the catalyst and pyrolysis char. A portion of these solid products can be returned to the screw feeder 40 through the catalyst recovery outlet 502 for further reaction, while another portion can enter the pulping unit 80 through the catalyst recovery outlet 502 for pulping treatment. Pyrolysis liquid products, such as light oils or hydrocarbons, can enter the heat exchanger 60 through the pyrolysis liquid product outlet 503 for heat exchange. The heat-exchanged pyrolysis liquid products can then enter the pulping unit 80 for pulping treatment. Furthermore, pyrolysis liquid products and / or pyrolysis gaseous products can enter the heat exchanger 60 for heat exchange. The heat-exchanged material (such as non-condensable gas) enters the burner 70 through the second outlet 602 of the heat exchanger 60 for combustion treatment. The combusted material can then be supplied to the heating inlet 504 of the pyrolysis unit 50 through the outlet of the burner 70 for heating the pyrolysis unit 50. Since the pyrolysis gas products still have a certain amount of heat, they can be supplied to the gas inlet 204 of the drying device 20 through the pyrolysis gas outlet 505. The pyrolysis gas products are used to heat the drying device 20. In addition, the flue gas at the outlet is discharged after being purified to meet the standards.

[0097] That is, in the embodiments of this application, under the action of a catalyst, municipal solid waste undergoes in-situ catalytic pyrolysis in the pyrolysis device 50. The heavy tar components in the pyrolysis liquid produced by pyrolysis are further cracked into small molecule hydrocarbons. The light oil and some water are cooled by the heat exchanger 60 (such as a condenser) and then used in the subsequent pulping device 80. The non-condensable gas produced by pyrolysis is burned by the burner 70 and then used to heat the pyrolysis device 50. The gas at the outlet of the pyrolysis device 50 still has a certain amount of heat and can be used to heat the drying device 20. The flue gas at the outlet is discharged after being purified to meet the standards.

[0098] Furthermore, after pyrolysis, the obtained pyrolysis solids mainly consist of waste catalyst and pyrolysis carbon. The catalyst and pyrolysis carbon can be discharged from the tail end of the pyrolysis unit 50, for example, via the catalyst recovery outlet 502. Part of the pyrolysis solids can be returned to the screw feeder 40, and the remaining pyrolysis solids can be supplied to the pulping unit 80. Optionally, in some embodiments, the total mass of the pyrolysis solids obtained from the pyrolysis treatment is m1, and the mass of the pyrolysis solids returned to the screw feeder 40 is m2, where m1 and m2 satisfy: m2 = (10%~30%)*m1. As examples, m2 = 10%*m1, 15%*m1, 20%*m1, 25%*m1, or 30%*m1, etc.

[0099] In this application, the catalyst may still retain some activity after a single-pass pyrolysis reaction, and the pyrolytic char obtained by pyrolysis typically has a rich porous structure and some trace metals, which show certain benefits for tar treatment. Therefore, the mixture of pyrolytic char and catalyst does not need to be sorted. 10% to 30% of the pyrolysis solids are added back to the screw feeder 40 and sent to the pyrolysis unit 50 to participate in the reaction again, improving the utilization efficiency of the catalyst. The remaining pyrolysis solids enter the slurry preparation unit 80, where they are ground and mixed with some pyrolysis oil to form a slurry for use as feedstock in the subsequent gasification system.

[0100] Therefore, by directly recycling the mixture containing waste catalyst and pyrolytic carbon, there is no need to consider the separation of catalyst and pyrolytic carbon in the mixture. On the one hand, the amount of catalyst used in the whole process can be reduced, thus reducing the cost of catalyst. On the other hand, the residual value of the catalyst can be fully utilized, which can play a role in regulating the melting temperature of municipal solid waste ash.

[0101] In this municipal solid waste treatment system, the pulping device 80 has a pyrolysis liquid inlet 801 and a solid inlet 802; the pulping device 80 also has a material outlet 803 for the material to be gasified. The gasification device 90 has a material inlet 901 for the material to be gasified.

[0102] The pyrolysis liquid inlet 801 of the pulping device 80 can be connected to the first outlet 601 of the heat exchanger 60; the solid inlet of the pulping device 80 can be connected to the recovered catalyst outlet 502 (pyrolysis solid material outlet) of the pyrolysis device 50; and the gasification material outlet 803 of the pulping device 80 is connected to the gasification material inlet 901 of the gasification device 90.

[0103] It should be noted that this application does not impose specific restrictions on the inlet and outlet settings of each device in the municipal solid waste treatment system. Each inlet or outlet only needs to be able to input or output the corresponding material; this does not limit the purpose of the invention. For example, the municipal solid waste inlet 201 and the fresh catalyst inlet 202 of the drying device 20 can be one inlet, two inlets, or the fresh catalyst inlet 202 can be connected to a pipeline connected to the municipal solid waste inlet 201. These can all be selected and set according to specific actual conditions.

[0104] In this application, the pulping device 80 described above can produce a slurry composed of pyrolytic carbon and oil mixed with a portion of the catalyst. The slurry is then transported to the gasification device 90, such as a gasifier. Under the high-temperature environment of the gasifier, the catalyst skeleton structure collapses, and the main component becomes SiO2. At high temperature, SiO2 combines with CaO in the pyrolytic carbon ash, consuming the excess CaO in the ash. This achieves the control of the melting temperature of the waste pyrolytic carbon ash and enables the direct utilization of the spent catalytic pyrolysis catalyst.

[0105] It should be noted that the above-mentioned pulping device and gasification device both adopt existing technologies. For example, the gasification device can adopt a fluidized bed. The specific structure and operation reaction principle of the pulping device and gasification device can refer to relevant existing technologies (such as relevant coal gasification equipment). This application does not limit them in this regard.

[0106] In some embodiments, a municipal solid waste treatment process is also provided, the process comprising the following steps:

[0107] The municipal solid waste to be treated and the fresh catalyst are respectively fed into the drying device 20 for drying treatment, and the municipal solid waste to be treated and the fresh catalyst are initially mixed in the drying device 20 to obtain the first mixture.

[0108] The first mixture is fed to the screw feeder 40 for secondary mixing to obtain the second mixture;

[0109] The second mixture is fed into the pyrolysis unit 50 for pyrolysis treatment to obtain pyrolysis solid material and pyrolysis liquid material;

[0110] The pyrolysis solid material includes a mixture of recovered catalyst and pyrolysis carbon. At least a portion of the pyrolysis solid material is returned to the screw feeder 40 to participate in the reaction again, and at least a portion of the pyrolysis liquid material is supplied to the pulping device 80 for pulping treatment.

[0111] The municipal solid waste treatment process provided in this invention is simple, easy to operate, highly feasible, and easy to industrialize.

[0112] It should be understood that the "domestic waste treatment system" and the "domestic waste treatment process" are based on the same inventive concept. All the features and advantages described above for the "domestic waste treatment system" also apply to the "domestic waste treatment process", and will not be repeated here.

[0113] Optionally, the aforementioned domestic waste to be treated is crushed waste, and the particle size of the crushed waste is ≤30mm.

[0114] In this application, the municipal solid waste needs to be crushed before being fed into the drying device 20. For example, the municipal solid waste, after being sorted and having inorganic materials such as glass and metal removed, is first crushed into particles smaller than 30mm on the crusher 10 to improve the calorific value and uniformity of the waste material. Then, the crushed waste can be fed into the drying device 20.

[0115] Optionally, the municipal solid waste material crushed by the crusher 10 can be dried together with fresh catalyst in a rotary kiln dryer. The fresh catalyst can be in powder or granular form. In this way, under high temperature and furnace rotation, some of the moisture in the waste can be removed and the catalyst and municipal solid waste material can be initially mixed. The resulting first mixture falls into the mixing bin 30 through the first mixture outlet 203 of the drying device 20.

[0116] In this embodiment of the application, the drying temperature is 120℃~150℃; for example, it can be any one of 120℃, 130℃, 140℃, 150℃ or any range between two.

[0117] Optionally, the mass of the fresh catalyst is 1% to 10% of the mass of the municipal solid waste to be treated; that is, the mass ratio of the fresh catalyst to the municipal solid waste to be treated is 1% to 10%, preferably around 5%. For example, this mass ratio can be any one of 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, or any range between two.

[0118] Optionally, the fresh catalyst used in this application can be a molecular sieve catalyst, such as a ZSM-5 molecular sieve catalyst or a USY molecular sieve catalyst.

[0119] Optionally, the first mixture is fed into the screw feeder 40 after passing through the mixing bin 30. That is, the first mixture obtained after processing by the drying device 20 enters the mixing bin 30, and the material exiting the mixing bin 30 is then fed into the screw feeder 40. The screw feeder 40 can function as both a material conveyor and a mixer. A second mixture can be obtained under the action of the screw feeder 40.

[0120] The aforementioned second mixture can be fed to the pyrolysis unit 50 by the screw feeder 40 for anaerobic pyrolysis. For example, by using a rotary kiln pyrolysis reactor, the mixing uniformity of the waste material and catalyst can be further enhanced by the rotation of the furnace body, allowing the catalyst to fully exert its catalytic effect. Optionally, the pyrolysis temperature is 350℃~450℃. By controlling the pyrolysis temperature within this range, a higher pyrolysis char yield can be obtained. As an example, the pyrolysis temperature can be any one of 350℃, 360℃, 370℃, 380℃, 400℃, 420℃, or 450℃, or a range between any two.

[0121] After the pyrolysis reaction is completed, pyrolysis solids, pyrolysis liquids, and pyrolysis gaseous products are obtained. The pyrolysis solids mainly include the catalyst and pyrolysis char. Optionally, a portion of the pyrolysis solids is returned to the screw feeder 40 to participate in the reaction again, while the remaining portion is fed to the pulping device 80 for pulping treatment. The slurry obtained from the pulping device 80 is then fed to the gasification device 90 for gasification treatment.

[0122] Optionally, the total mass of the pyrolysis solids obtained from the pyrolysis treatment is m1, and the mass of the pyrolysis solids returned to the screw feeder 40 is m2. m1 and m2 satisfy the following condition: m2 = (10%–30%) * m1. In this embodiment, 10%–30% of the pyrolysis solids are re-added to the screw feeder 40 and sent to the pyrolysis unit 50 to participate in the reaction again, improving the utilization efficiency of the catalyst. The remaining pyrolysis solids enter the slurry preparation unit 80, where they are ground and mixed with some pyrolysis oil to form a slurry for use as feedstock in the subsequent gasification system.

[0123] Therefore, based on the above, the municipal solid waste treatment system and process provided in this application is a process system and method that can synergistically treat waste catalyst from municipal solid waste catalytic pyrolysis and regulate the ash melting temperature of municipal solid waste. It not only achieves direct utilization of deactivated waste catalyst, avoiding complex catalyst sorting and separation processes, reducing the difficulty of the process route, and increasing the utilization value of waste catalyst; but also allows for in-situ regulation of the ash melting point of high-calcium, low-silicon-aluminum content materials (such as municipal solid waste) from the raw material end, reducing the complexity of subsequent ash melting point regulation processes. Simultaneously, due to the role of the catalyst during the pyrolysis reaction, the quality of the pyrolysis oil is improved, the oxygen content is reduced, and the calorific value is increased. Thus, the subsequent mixing of pyrolysis oil and pyrolysis char for gasification feedstock also results in a correspondingly higher calorific value. Therefore, the impact of using waste catalyst to regulate the ash melting point of waste on the calorific value of the gasification feedstock is smaller compared to substances such as quartz.

[0124] In some embodiments, a system for producing methanol from municipal solid waste through co-gasification with biomass is also provided, comprising the aforementioned municipal solid waste treatment system and a methanol synthesis unit; wherein the outlet of the gasification unit 90 in the municipal solid waste treatment system is connected to the inlet of the methanol synthesis unit. The municipal solid waste treatment system and process of this application can be applied to the production of methanol from municipal solid waste through co-gasification with biomass to achieve resource utilization and reduce methanol production costs. Other devices in the methanol production system, such as the methanol synthesis unit, can refer to existing technologies and are not limited thereto.

[0125] The following describes the implementation methods of this application. The implementation methods described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the implementation methods, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents, materials, or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0126] Example 1

[0127] A municipal solid waste treatment process includes the following steps:

[0128] First, the sorted household waste, after removing inorganic materials such as glass and metal, is crushed to a particle size of less than 30mm in a crusher.

[0129] The municipal solid waste to be treated and the fresh catalyst (molecular sieve catalyst, such as ZSM-5 molecular sieve catalyst or USY molecular sieve catalyst) are then fed into a drying device (rotary dryer) for drying. The drying temperature is 120℃~150℃. The fresh catalyst can be in powder or granular form. The mass ratio of the fresh catalyst to the municipal solid waste to be treated is 1%~10%, preferably about 5%. The municipal solid waste to be treated and the fresh catalyst are initially mixed in the drying device to obtain the first mixture.

[0130] The first mixture obtained after being processed by the drying device enters the mixing silo. The material coming out of the mixing silo is then fed to the screw feeder for secondary mixing to obtain the second mixture.

[0131] The second mixture is fed into the pyrolysis unit by a screw feeder for anaerobic pyrolysis. The rotary kiln pyrolysis reactor further enhances the uniformity of mixing between the waste material and the catalyst through furnace rotation, allowing the catalyst to fully exert its catalytic effect. Relying on the catalytic effect of the catalyst, the pyrolysis temperature can be set to a lower temperature of 350℃~450℃ to obtain a higher pyrolysis char yield.

[0132] Under the action of a catalyst, municipal solid waste undergoes in-situ catalytic pyrolysis in a pyrolysis unit. The heavy tar components in the pyrolysis liquid are further cracked into small molecule hydrocarbons. Light oil and some water are cooled by a heat exchanger (such as a condenser) and then used in a subsequent pulping unit. The non-condensable gas produced by pyrolysis is burned by a burner and then used to heat the pyrolysis unit. The gas at the outlet of the pyrolysis unit still has a certain amount of heat and can be used to heat the drying unit. The flue gas at the outlet is purified and discharged after meeting the standards.

[0133] After pyrolysis, the obtained pyrolysis solids mainly consist of spent catalyst and pyrolysis char, which can be discharged from the tail end of the pyrolysis unit. A portion of the pyrolysis solids can be returned to the screw feeder, while the remainder can be fed to the slurry preparation unit. In this application, after a single-pass pyrolysis reaction, the catalyst may still retain some activity, and the pyrolysis char obtained typically has a rich porous structure and some trace metals, showing certain benefits for tar treatment. Therefore, the mixture of pyrolysis char and catalyst does not need to be sorted; 10%–30% of the pyrolysis solids are added back to the screw feeder and sent to the pyrolysis unit to participate in the reaction again, improving catalyst utilization efficiency. The remaining pyrolysis solids enter the slurry preparation unit, are ground, and then mixed with some pyrolysis oil to form a slurry for use as feedstock in the subsequent gasification system.

[0134] To verify that adding waste catalyst can be used to control the ash melting problem of municipal solid waste, the following experiments were conducted in this embodiment.

[0135] Using the municipal solid waste ash described in Table 1 as a base, different proportions of ZSM-5 catalyst were added to it, and the ash melting point temperature was measured. The results are shown in Table 2.

[0136] Table 1 Chemical composition and flow temperature of paper ash and municipal solid waste ash

[0137]

[0138] In Table 1, FT represents the flow temperature.

[0139] In addition, the four characteristic temperatures of ash are described in the national standard GB / T219-2008, so the characteristic descriptions of paper ash, household waste ash, etc. in Table 1 can be referred to this description.

[0140] As can be seen from Table 1, the calcium content in paper ash is extremely high. Since about 20-25% of the components in garbage are paper, the calcium content in garbage ash is also relatively high to some extent.

[0141] Table 2 Ash melting temperature of municipal solid waste ash mixed with catalyst flux

[0142]

[0143] In Table 2, directly added SiO2 is used to represent molecular sieve catalysts. Since the SiO2 content varies in molecular sieve catalysts other than pure silicon molecular sieves due to different silicon-to-aluminum ratios, the amount of SiO2 added is used here for judgment. In actual operation, adjustments can be made based on the SiO2 content in the molecular sieve.

[0144] Table 2 shows that adding molecular sieve catalysts can regulate the melting temperature of municipal solid waste ash. When the addition ratio is 20%, the ash melting point decreases from 1442℃ to 1111℃, but when the addition ratio is greater than 20%, the melting temperature begins to rise. Therefore, in actual production, adding an appropriate proportion of molecular sieve catalysts can significantly reduce the ash melting point.

[0145] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0146] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0147] It should be noted that the terms "and / or" or " / " used herein are merely descriptions of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The singular forms "a," "described," and "the" used in the embodiments of the invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0148] In the detailed description and claims, a list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A domestic waste processing system for the production of methanol, characterised in that, The household garbage treatment system comprises: a screw feeder (40) having a first mixed material inlet (401) for inputting household garbage and fresh catalyst, a recovered catalyst inlet (402), and a second mixed material outlet (403); a pyrolysis device (50) having a second mixed material inlet (501) connected with the second mixed material outlet (403) and a recovered catalyst outlet (502) connected with the recovered catalyst inlet (402); a slurry preparation device (80) having a solid inlet (802) connected with the recovered catalyst outlet (502); the slurry preparation device (80) further has a gasification material outlet (803); a gasification device (90) having a gasification material inlet (901) connected with the gasification material outlet (803); in the gasification device, direct utilization of waste catalyst after catalytic pyrolysis is realized, and the catalyst is a molecular sieve catalyst.

2. The household waste processing system according to claim 1, characterized in that The household garbage treatment system further comprises a crusher (10) and a drying device (20) having a household garbage inlet (201), a fresh catalyst inlet (202), and a first mixed material outlet (203) connected with the first mixed material inlet (401); an outlet of the crusher (10) is connected with the household garbage inlet (201).

3. The household waste processing system according to claim 2, characterized in that the drying device (20) comprises a rotary furnace dryer; and / or, the pyrolysis device (50) comprises a rotary furnace pyrolysis reactor.

4. The household waste processing system according to claim 2, characterized in that The household garbage treatment system further comprises a mixing bin (30) located between the drying device (20) and the screw feeder (40), an inlet of the mixing bin (30) is connected with the first mixed material outlet (203), and an outlet of the mixing bin (30) is connected with the first mixed material inlet (401); and / or, The household garbage treatment system further comprises a heat exchanger (60), a combustor (70), and a slurry preparation device (80), the pyrolysis device (50) further has a pyrolysis liquid product outlet (503) and a heat supply inlet (504), and the slurry preparation device (80) has a pyrolysis liquid inlet (801); the pyrolysis liquid product outlet (503) is connected with an inlet of the heat exchanger (60), a first outlet (601) of the heat exchanger (60) is connected with the pyrolysis liquid inlet (801), a second outlet (602) of the heat exchanger (60) is connected with an inlet of the combustor (70), and an outlet of the combustor (70) is connected with the heat supply inlet (504); and / or, The pyrolysis device (50) further has a pyrolysis gas outlet (505) connected with a gas inlet (204) of the drying device (20).

5. A process for the preparation of methanol from domestic waste, characterized in that, The household garbage treatment system according to any one of claims 1-4, comprising the following steps: a mixture containing the household garbage to be treated and fresh catalyst is fed into a screw feeder (40) for mixing to obtain a mixed material; the mixed material is fed into a pyrolysis device (50) for pyrolysis treatment to obtain pyrolysis solid material and pyrolysis liquid material; wherein the pyrolysis solid material comprises a mixture of recovered catalyst and pyrolysis carbon, at least part of the pyrolysis solid material is returned to the screw feeder (40) for further reaction, and at least part of the pyrolysis liquid material is fed into a pulping device (80) for pulping treatment.

6. The process according to claim 5, wherein The treatment process further comprises: the household garbage to be treated and fresh catalyst are separately fed into a drying device (20) for drying treatment, and the household garbage to be treated and fresh catalyst are initially mixed in the drying device (20) to obtain a first mixed material; then, the first mixed material is fed into a screw feeder (40) for mixing.

7. The process according to claim 6, characterized in that, The treatment process satisfies at least one of the following features (1)-(10): (1) the temperature of the drying treatment is 120-150°C; (2) the mass of the fresh catalyst is 1-10% of the mass of the household garbage to be treated; (3) the temperature of the pyrolysis treatment is 350-450°C; (4) the total mass of the pyrolysis solid material obtained by the pyrolysis treatment is m1, the mass of the pyrolysis solid material returned to the screw feeder (40) is m2, and m1 and m2 satisfy: m2=(10-30)%*m1; (5) the household garbage to be treated is broken garbage, and the particle size of the broken garbage is ≤30mm; (6) the first mixed material is fed into the screw feeder (40) after passing through a mixing bin (30); (7) part of the pyrolysis solid material is returned to the screw feeder (40) for further reaction, and the remaining part of the pyrolysis solid material is fed into a pulping device (80) for pulping treatment, and pulp obtained by the pulping device (80) is fed into a gasification device (90) for gasification treatment; (8) the pyrolysis liquid material is fed into the pulping device (80) for pulping treatment after heat exchange in a heat exchanger (60); (9) part of the pyrolysis gas material obtained by the pyrolysis treatment is fed into a combustor (70) after heat exchange in the heat exchanger (60), and the material after combustion of the combustor (70) is fed into the pyrolysis device (50) for heating the pyrolysis device (50); (10) part of the pyrolysis gas material obtained by the pyrolysis treatment is fed into the drying device (20) for drying treatment.

8. A system for preparing methanol from municipal solid waste and biomass in a gasification process, characterized in that, The household garbage treatment system according to any one of claims 1-4, and a methanol synthesis device; wherein the outlet of the gasification device (90) in the household garbage treatment system is connected with the inlet of the methanol synthesis device.

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