A biomass carbonization pretreatment system and method coupled with green methanol production

Abstract

The present application provides a kind of biomass charring system coupled with methanol production. Specifically, the present application provides a biomass charring system coupled with methanol production, wherein the system comprises a biomass charring module, a methanol production module, and an air separation module. The present system realizes deep coupling of biomass charring and methanol production, reduces energy consumption and the demand for nitrogen, and realizes the recycling of heat energy in the biomass charring process and the methanol synthesis process and the synergistic utilization of charring by-products. The present system significantly reduces the required cost while improving the utilization rate of materials and carbon resources in the whole system.

Description

Technical Field

[0001] This invention relates to the field of energy and chemical production, and in particular to a biomass carbonization pretreatment system and method coupled with green methanol production. Background Technology

[0002] Driven by global low-carbon goals, the demand for green methanol and green jet fuel in high-carbon industries such as shipping and aviation, which are difficult to electrify, is experiencing explosive growth. Policies such as the International Maritime Organization (IMO) and the European Union Carbon Market (ETS) are further mandating the replacement of marine fuels with green fuels. The synthesis of green methanol through biomass gasification coupled with green hydrogen is currently the most promising low-carbon fuel production route for industrialization, capable of achieving near-zero carbon emissions throughout its entire life cycle.

[0003] Biomass carbonization pretreatment is a core upstream step in the entire biomass-to-green methanol production chain. Its product quality, energy consumption level, and operational stability directly determine the downstream gasification efficiency, synthesis catalyst life, and overall project economics. Currently, the industry has begun to explore the integrated design of biomass carbonization and methanol production, but existing solutions all have significant technical shortcomings and cannot meet the engineering implementation requirements of large-scale green methanol projects. Summary of the Invention

[0004] One of the objectives of this invention is to provide a biomass carbonization pretreatment system and method coupled with green methanol production; The second objective of this invention is to achieve a system coupling and energy cascade utilization technology between biomass carbonization pretreatment and the entire downstream green methanol / jet fuel production process.

[0005] The third objective of this invention is to deeply couple biomass carbonization with green methanol synthesis and production, thereby achieving energy cascade utilization, shared public systems, and full-scale collaborative treatment of by-products, and fundamentally reducing the investment and operating costs of the carbonization system.

[0006] In a first aspect of the invention, a biomass carbonization system coupled with methanol production is provided, the system comprising a biomass carbonization module, a methanol production module, and an air separation module, wherein... The biomass carbonization module includes: a crushing and screening pretreatment unit, a heat exchange unit, a carbonization pretreatment unit, and a tail gas circulation fan; wherein... The crushing and screening pretreatment unit includes: a biomass raw material inlet and a biomass outlet; The heat exchange unit includes: a gas inlet and a hot flue gas outlet; The carbonization pretreatment unit includes: a biomass feed inlet, a hot flue gas inlet, a biomass char outlet, and a carbonization tail gas outlet; The biomass outlet of the crushing and screening pretreatment unit is connected to the biomass inlet of the carbonization pretreatment unit. The hot flue gas outlet of the heating unit is connected to the hot flue gas inlet of the carbonization pretreatment unit via a pipeline. 80%-90% of the carbonization tail gas of the carbonization pretreatment unit is sent to the gas inlet of the heat exchange unit via a pipeline through a tail gas circulation fan. The methanol production module includes: a pulverizing unit, a gasification unit, a syngas purification unit, a methanol synthesis unit, and a methanol finished product receiving unit; wherein... The powder-making unit includes: a biochar inlet and a biochar powder outlet; The gasification unit includes: an oxygen inlet, a biomass charcoal powder inlet, and a combustible gas outlet; The syngas purification unit includes: a combustible gas inlet and a syngas outlet; The methanol synthesis unit includes: a synthesis gas inlet and a methanol product outlet; The methanol product receiving unit includes: a methanol product inlet; The biochar outlet of the carbonization pretreatment unit is connected to the biochar inlet of the pulverizing unit; the biochar powder outlet of the pulverizing unit is connected to the biochar powder inlet of the gasification unit; the combustible gas outlet of the gasification unit is connected to the combustible gas inlet of the syngas purification unit via a pipeline; the syngas outlet is connected to the syngas inlet via a pipeline; and the methanol product outlet of the methanol synthesis unit is connected to the methanol product inlet of the methanol product receiving unit via a pipeline. The air separation module includes: an air inlet, an oxygen outlet, and a nitrogen outlet. The oxygen outlet of the air separation module is connected to the oxygen inlet of the gasification unit via a pipeline, and the nitrogen outlet of the air separation module is connected to the gas inlet of the heating unit. After the air enters the air separation module, the oxygen and nitrogen are separated. The oxygen enters the gasification unit through the oxygen outlet via a pipeline, and the nitrogen enters the heating unit through the nitrogen outlet via a pipeline.

[0007] In another preferred embodiment, the carbonization pretreatment unit includes a drying unit and a carbonization unit connected in series. The drying unit is used to dry the biomass, and the carbonization unit is used to carbonize the dried biomass.

[0008] In another preferred embodiment, the system further includes: a gas-fired boiler unit, a steam header unit, and a chimney exhaust unit, wherein, The gas-fired boiler unit includes: a venting gas and flash steam inlet, a third steam outlet, and a flue gas outlet; The steam header unit includes: a first steam inlet, a second steam inlet, a third steam inlet, and a steam outlet; The chimney emission unit includes a flue gas inlet; The methanol synthesis unit of the system also includes: a first steam outlet, a purge gas outlet, and a flash vapor outlet; The system vaporization unit further includes: a second steam outlet; The system heat exchange unit also includes a steam inlet; The steam outlet of the steam header unit is connected to the steam inlet of the heat exchange unit via a pipeline; the purge gas and flash steam outlets of the methanol synthesis unit are connected to the purge gas and flash steam inlets of the gas-fired boiler unit via pipelines; the flue gas outlet of the gas-fired boiler unit is connected to the flue gas inlet of the chimney emission unit via a pipeline; the first steam outlet of the methanol synthesis unit is connected to the first steam inlet of the steam header unit via a pipeline; the second steam outlet of the gasification unit is connected to the second steam inlet of the steam header unit via a pipeline; and the third steam outlet of the gas-fired boiler unit is connected to the third steam inlet of the steam header unit via a pipeline.

[0009] In another preferred embodiment, a closed scraper conveyor is provided between the carbonization pretreatment unit and the pulverizing unit to feed the biomass char outlet of the carbonization pretreatment unit into the biomass char inlet of the pulverizing unit. A pneumatic conveying system is provided between the pulverizing unit and the gasification unit to deliver the biochar powder from the biochar powder outlet of the pulverizing unit to the biochar powder inlet.

[0010] In another preferred embodiment, the heat exchange unit further includes a condensate outlet; the gas boiler unit further includes a condensate inlet; wherein the condensate outlet of the heat exchange unit is connected to the condensate inlet of the gas boiler unit via a pipe.

[0011] In another preferred embodiment, the carbonized exhaust gas is further purified using a cyclone dust collector when it enters the heat exchange unit via an exhaust gas recirculation fan.

[0012] In another preferred embodiment, the system gas boiler unit further includes: a carbonization tail gas inlet; The pipeline that sends 80%-90% of the carbonization tail gas from the carbonization pretreatment unit to the gas inlet of the heat exchange unit via the tail gas circulation fan also includes a branch line. The branch line delivers 10%-20% of the carbonization tail gas to the carbonization tail gas inlet of the gas-fired boiler unit, and a pump valve is installed between the branch line and the main pipeline.

[0013] In another preferred embodiment, the system further includes safety interlocking devices, wherein the safety interlocking devices include: process parameter over-limit interlocking devices and equipment operating status interlocking devices.

[0014] In another preferred embodiment, the process parameters include, but are not limited to, oxygen content and combustible gas concentration.

[0015] In another preferred embodiment, the operating status of the equipment includes, but is not limited to, equipment pressure and equipment temperature.

[0016] In another preferred embodiment, the system also includes integration with a public system.

[0017] In another preferred embodiment, the utility system includes a nitrogen system, a circulating cooling water system, a compressed air system, and an electrical system.

[0018] In another preferred embodiment, the system further includes an algorithm model for integrated control of the entire process.

[0019] In another preferred embodiment, the biomass carbonization module is used in conjunction with a material level monitoring system in the silo.

[0020] In another preferred embodiment, the algorithm model is selected from the group consisting of: dynamic control model based on real-time load, model predictive control, and PID adaptive control.

[0021] In a second aspect, the present invention provides a method for the carbonization of biomass coupled with methanol production, comprising the following steps: S1. Separate nitrogen and oxygen from the air to obtain oxygen and nitrogen; S2. The nitrogen obtained in step S1 and the carbonization tail gas generated during the carbonization of 80%-90% of biomass are heat-exchanged with the steam in the steam header to generate hot flue gas and condensate. S3. The hot flue gas obtained in step S2 is subjected to carbonization pretreatment together with the crushed and screened biomass to prepare biochar. Then the biochar is pulverized to prepare biochar powder. S4. The oxygen obtained in step S1 and the biomass char powder obtained in step S3 are fed into the gasification unit for gasification treatment to prepare combustible gas and second steam. S5. After purifying the combustible gas obtained in step S4, methanol is synthesized to prepare methanol, first vapor, purge gas and flash vapor. S5. The condensate obtained in step S3 is sent to the gas boiler for water supply. The carbonization tail gas from 10%-20% of the biomass carbonization, the release gas obtained in step S5, and the flash steam are sent to the gas boiler for combustion. The tail gas is discharged after meeting the standards, and the third steam is prepared at the same time.

[0022] In another preferred embodiment, the steam preparation of the steam header includes the following steps: N1, the first vapor generated during methanol synthesis; N2, the second steam generated during the gasification of recycled biomass charcoal powder; N3, the third steam generated when the carbonization tail gas, purge gas and flash steam of 10%-20% biomass carbonization are sent to the gas-fired boiler for combustion. N4. The steam recovered in steps N1, N2, and N3 is sent to the steam header to prepare the steam for the steam header.

[0023] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a biomass carbonization system for coupled methanol production according to an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of a biomass carbonization system coupled with methanol production according to Embodiment 2 of this application. Detailed Implementation

[0026] Through extensive and in-depth research, the inventors have discovered for the first time a biomass carbonization system coupled with methanol production. This system achieves deep coupling between biomass carbonization and methanol production, reducing the demand for nitrogen and enabling the recycling of heat energy and the synergistic utilization of carbonization byproducts during both processes. This system significantly reduces costs while also improving the overall utilization rate of materials and carbon resources. Based on this, the present invention was completed.

[0027] the term Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0028] As used herein, the terms “comprising,” “including,” and “containing” are used interchangeably and include not only closed definitions but also semi-closed and open definitions. In other words, the terms include “consisting of” and “substantially consisting of”.

[0029] As used herein, when referring to a specific enumerated value, the term “about” means that the value can vary by no more than 1% from the enumerated values. For example, as used herein, the expression “about 100” includes all values ​​between 99 and 101 (e.g., 99.1, 99.2, 99.3, 99.4, etc.).

[0030] Disadvantages of existing technology Existing biomass carbonization pretreatment systems mostly operate independently, relying on high-quality energy sources such as natural gas and biomass combustion for heat. The pyrolysis gas produced as a byproduct of carbonization is often directly burned and emitted, failing to integrate with downstream gasification and green methanol synthesis chemical systems. This results in low overall energy efficiency and high operating costs. The main drawbacks are as follows: First, the biomass carbonization process is a high-energy-consuming process, requiring a continuous input of a large amount of heat energy to maintain the reaction conditions. The independently set heat source system not only increases the project investment and operating costs, but also causes a loss of energy cascade utilization efficiency. Secondly, the biomass carbonization unit is isolated from the downstream gasification and methanol synthesis units, which only achieves simple material transportation and fails to achieve deep coupling of heat energy, utility systems, tail gas treatment and load control. This results in the independent construction of utility systems for each unit and the repeated installation of nitrogen production, circulating water and tail gas treatment equipment, which significantly increases the project investment and operating costs.

[0031] Overall solution of the present invention Based on the material and energy characteristics of the entire green methanol synthesis process, an engineering scheme with four coupling dimensions is proposed.

[0032] (1) Coupling of thermal energy cascade utilization: The low-pressure steam by-product of methanol synthesis section, the waste heat of high-temperature synthesis gas in gasifier, and the combustion heat of methanol synthesis off-gas are recovered as auxiliary heat sources for drying and carbonization processes in carbonization system, reducing the consumption of external heat sources in carbonization system; at the same time, the waste heat of carbonization products and pyrolysis gas is recovered for raw material pre-drying, realizing the cascade utilization of thermal energy throughout the process.

[0033] (2) Carbonization tail gas treatment coupling: After purification, part of the carbonization tail gas is used as inert protection gas for the carbonization system and the remaining part is sent to the gas boiler to recover heat. No separate tail gas treatment device is set up.

[0034] (3) Material transfer and process flow coupling: The carbonization system discharge is directly and closedly transported to the pulverizing unit, and then directly connected to the gasifier feeding system through the pneumatic conveying system, realizing the closed and continuous conveying of the whole process of "carbonization-pulverizing-gasification", reducing intermediate storage and transfer links, reducing material loss and equipment investment, while avoiding material moisture absorption and oxidation, and ensuring stable feed quality.

[0035] (4) Coupling of public systems and control systems: The public works such as nitrogen, circulating cooling water, compressed air and fire protection systems of the carbonization system are all shared with the chemical system, and no separate construction is required, which greatly reduces equipment investment and operation and maintenance costs; the DCS control system of the carbonization system communicates and links with the DCS system of the gasification and methanol synthesis section, and dynamically adjusts the processing capacity of the carbonization system according to the load changes of the chemical system, so as to realize the integrated coordinated control of the whole process.

[0036] Energy utilization rate of this invention Compared with existing technologies, this invention breaks through the technical barriers that separate biomass carbonization pretreatment from downstream gasification and methanol synthesis units, and achieves deep coupling of the entire process in multiple dimensions.

[0037] This invention constructs a three-stage closed-loop cascade utilization system for methanol synthesis-gasification-carbonization, achieving differentiated matching and efficient utilization of thermal energy. This significantly reduces the external heat energy input to the carbonization unit and effectively improves the overall energy utilization rate. Furthermore, through deep coupling of common systems, it enables the co-construction and sharing of common utilities such as nitrogen and circulating water, avoiding redundant equipment investment, reducing investment per unit capacity, and lowering the operating cost of the carbonization unit. Through full-process material-load coordinated control, this invention achieves 100% compatibility between the quality of carbonization products and the requirements of downstream gasification feed, solving the pain points of poor product compatibility and insufficient system stability in existing technologies. By coupling the consumption of by-products with downstream systems, it achieves full on-plant utilization of carbonization by-products, significantly reducing environmental treatment costs. This invention can be directly applied to the engineering design and implementation of a 100,000-ton-level green methanol / aviation fuel integrated project.

[0038] The main advantages of this invention include: (1) The methanol synthesis-gasification-carbonization three-stage thermal energy closed-loop cascade utilization system in this invention is based on the precise matching of thermal energy levels in the three production stages, realizing the differentiated utilization and closed-loop recovery of thermal energy, fundamentally solving the industry pain point of high energy consumption in the biomass carbonization process.

[0039] (2) The present invention constructs a common system deep coupling module for carbonization unit and gasification and methanol synthesis unit, realizing the co-construction and sharing of common works such as nitrogen, circulating water and instrument air, avoiding repeated equipment investment and greatly reducing project investment and operating costs.

[0040] (3) The present invention establishes a material-load coordinated linkage control system for the entire process of carbonization-gasification-methanol synthesis, which realizes precise load matching of the three production units and adaptive control of carbonization product quality, ensuring 100% compatibility between carbonization products and gasification feed requirements, and greatly improving the stability of continuous system operation.

[0041] (4) This invention constructs a coupled disposal path for carbonization by-products and downstream gasification and syngas purification units, realizing the full-scale synergistic utilization of carbonization by-products within the plant, which not only reduces environmental treatment costs but also improves the utilization rate of materials and carbon resources in the entire system.

[0042] The present invention will be further illustrated 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 invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, percentages and parts are weight percentages and parts by weight.

[0043] Example 1: In the entire process of green methanol synthesis, there is a large amount of recoverable low-grade waste heat, which can cover part of the heat consumption demand of the biomass carbonization system. In this embodiment, a four-stage thermal energy cascade coupling scheme is used to realize the recovery and utilization of waste heat, effectively reducing the external energy consumption of the carbonization system.

[0044] Primary heat source: Low-pressure saturated steam, a byproduct of the methanol synthesis process. The methanol synthesis reaction is a strongly exothermic reaction, and the methanol synthesis section can produce 2.5MPa steam as a byproduct, which is the core heat source of the carbonization system.

[0045] The coupling scheme of this embodiment is as follows: the by-product steam from methanol synthesis is directly connected to the heat exchange system of the carbonization pretreatment unit through the heat exchange pipeline network to provide a constant temperature heat source for the low-temperature carbonization reaction; the condensate (temperature ≥100℃) after steam heat exchange is returned to the boiler feedwater system of the chemical system to form a closed loop.

[0046] Secondary heat source: Waste heat from high-temperature syngas in the gasifier The gasifier uses an entrained flow gasifier, and the syngas temperature at the gasifier outlet reaches as high as 1300℃. After being recovered by the waste heat boiler, 1.6~2.5MPa steam can be produced as a by-product, which can be used as a supplementary heat source for the carbonization system.

[0047] This implementation coupling scheme involves directly connecting the by-product steam from the gasification unit to the heat exchange system of the carbonization pretreatment unit via a steam header.

[0048] Tertiary heat source: Waste heat from the combustion of methanol synthesis off-gas The methanol synthesis process generates off-gas containing combustible components such as H2, CO, and CH4. Traditional processes often directly feed this off-gas into a flare for combustion, resulting in energy waste. After recovering hydrogen from the methanol synthesis off-gas through pressure swing adsorption, the remaining desorbed gas mainly consists of hydrogen and methane, which is a high-quality clean fuel that can be sent to a boiler station for fuel recovery.

[0049] This implementation coupling scheme involves burning methanol synthesis off-gas in a gas-fired boiler, and then feeding the resulting steam into the carbonization system. The carbonization system's associated hot blast stove produces steam at 200-250°C, which serves as a supplementary and peak-shaving heat source for the raw material drying and carbonization systems, ensuring system stability under fluctuating raw material characteristics and load changes. Alternatively, waste heat from the gas-fired boiler flue gas can be utilized, with the purified combustion gas fed into the carbonization unit as a drying medium, achieving full waste heat recovery.

[0050] Fourth-stage waste heat: Waste heat recovery and utilization from the carbonization system To address the waste heat generated by the carbonization system itself, an in-plant recovery and recycling system will be established to achieve optimal energy utilization. (1) Waste heat recovery from cooling of carbonization products: The temperature of the biomass char discharged from the carbonization pretreatment unit is about 200℃~240℃. A closed-loop spiral cooler is used, with nitrogen gas from the heat exchange unit as the cooling medium to recover the waste heat of the biomass char. The nitrogen gas is preheated from room temperature to above 150℃ to reduce the heat source consumption of the drying process. (2) Waste heat recovery of carbonization tail gas: The tail gas discharged during the carbonization process still has a high temperature. After being removed by cyclone dust removal, it is recycled back into the carbonization furnace.

[0051] Exhaust gas treatment coupling solution The low-temperature carbonization process of biomass produces byproducts such as pyrolysis gas, tar, wood vinegar, and non-condensable tail gas. This study has developed a full-scale resource utilization coupling scheme, in which all byproducts are utilized in conjunction with downstream chemical systems, resulting in no secondary pollution and improving the overall economic efficiency of the project. This scheme can increase the resource utilization rate of byproducts to 100% and eliminate solid waste discharge.

[0052] Carbonization tail gas recycling and co-utilization scheme The non-condensable exhaust gas produced by the carbonization system, after purification, mainly consists of N2, CO2, and a small amount of combustible components, with extremely low oxygen content (≤0.2 vol%), making it an excellent inert protective gas.

[0053] This implementation scheme adopts a "recycling as the main method and surplus disposal as a supplementary method" approach. After being purified by cyclone dust removal, about 80% to 90% of the carbonization tail gas is sent to the carbonization reactor through a circulating fan as an inert protective gas to replace purchased nitrogen, thereby reducing nitrogen consumption and operating costs. The remaining tail gas is sent to the chemical system's gas boiler for combustion, achieving zero exhaust gas discharge.

[0054] exhaust gas harmless treatment solution During the low-temperature carbonization process, the tail gas of biomass carbonization includes a small amount of pyrolysis gas and tar produced by pyrolysis. The main components of the pyrolysis gas are combustible components such as CO, CO2, H2, CH4, and CnHm, while the main components of the tar are organic components such as phenols, organic acids, and aromatics. It cannot be directly emitted.

[0055] This implementation scheme combines two approaches: First, a portion of the exhaust gas generated during the carbonization process is recycled. The remaining exhaust gas is then fed into a gas-fired boiler system via a closed pipeline for combustion. This scheme eliminates the need for exhaust gas incineration and flue gas purification devices in traditional carbonization systems, significantly reducing equipment investment and maintenance costs.

[0056] Material transfer coupling scheme Material transfer end-to-end coupling solution In traditional processes, biomass carbonization, pulverization, and gasification are designed independently, with multiple raw material and product silos in between. Transportation is done by truck or through open conveyors, resulting in high material loss (≥5%), susceptibility to moisture absorption and mold growth, large footprint, and high investment costs. This study proposes a closed-loop, continuous conveying coupling scheme for the entire "carbonization-pulverization-gasification" process. (1) The biomass char discharged from the carbonization reactor is cooled and then directly fed into the ultrafine coal mill of the pulverizing unit via a closed scraper conveyor, without the need for intermediate storage. (2) The biomass ultrafine powder produced by the coal mill is classified and collected, and then directly and sealed to the feed hopper at the top of the gasifier through the pneumatic conveying system, which is seamlessly connected with the gasification system. (3) The entire process is protected by inert gas, and the oxygen content is controlled below 0.5 vol% throughout the process to avoid material oxidation and spontaneous combustion, and to ensure safe transportation; (4) The material silo is equipped with material level monitoring and interlocked with the carbonization system, pulverizing system and gasification system. The processing capacity of the carbonization system is dynamically adjusted according to the feed amount of the gasifier to achieve supply and demand balance throughout the process.

[0057] (5) Benefits: This solution can reduce more than 3 intermediate storage warehouses, reduce the system footprint and equipment investment, reduce material loss, and greatly improve the continuity and stability of the entire process.

[0058] Public system shared coupling scheme All utilities required for the biomass carbonization system are shared with the downstream chemical system and do not need to be constructed separately. Specific coupling schemes are shown in Table 1. Table 1 Shared Coupling Scheme for Public Systems Integrated Coupling Scheme for Control Systems The carbonization system adopts a DCS distributed control system, which achieves bidirectional communication and linkage with the DCS systems of the downstream gasification and methanol synthesis sections. The core coupling functions are: (1) Load linkage control: Based on the operating load of the methanol synthesis section and the gasifier, the feed rate, carbonization temperature and heat source flow rate of the carbonization system are automatically adjusted to achieve adaptive matching of the load throughout the process and avoid material accumulation or insufficient supply. (2) Data sharing and centralized monitoring: The operating parameters, equipment status and alarm information of the carbonization system are all uploaded to the central control room of the chemical system, realizing centralized monitoring and unified scheduling of the whole plant. There is no need to set up a separate control room for the carbonization system, reducing the configuration of operation and maintenance personnel (approximately 30% reduction in operation and maintenance personnel). (3) Safety interlocking: The emergency shutdown, oxygen content exceeding standard interlocking, and over-temperature and over-pressure interlocking of the carbonization system are linked with the gasification system feeding system and public system to ensure the safe operation of the entire plant (for example, when the gasifier trips, the carbonization system immediately cuts off the feed and purges).

[0059] Based on the aforementioned four-stage heat source recovery, this invention constructs a biomass carbonization pretreatment system coupled with green methanol production. The biomass carbonization system coupled with green methanol production is as follows: Figure 1 As shown.

[0060] This system pre-treats biomass raw materials by crushing and screening them in a crushing and screening pre-treatment unit, and then sends them to a carbonization pre-treatment unit. At the same time, oxygen and nitrogen in the air are separated, and the nitrogen is sent through a heat exchange unit to generate hot flue gas. The hot flue gas is then sent to the carbonization pre-treatment unit to carbonize the biomass.

[0061] 80-90% of the carbonization tail gas generated during the carbonization process is used as inert protective gas to replace purchased nitrogen. It is sent to the heat exchange unit through the tail gas circulation fan to generate hot flue gas to carbonize biomass, thereby reducing nitrogen consumption and operating costs. The remaining 10-20% of the carbonization tail gas is sent to the gas boiler unit through a branch of the tail gas circulation fan pipeline.

[0062] While the heat exchange unit generates hot flue gas, the condensate produced is sent into the gas-fired boiler unit as boiler feedwater.

[0063] After the biochar is fed into the pulverizing system for pulverization, it is sent to the gasification unit. At the same time, oxygen separated from the air is sent to the gasification unit to gasify the biochar powder. During the gasification of the biochar powder, combustible gas and secondary steam are generated. The combustible gas is sent to the syngas purification unit for purification, and the secondary steam is sent to the steam collector unit for collection.

[0064] The purified combustible gas is sent to the methanol synthesis unit to synthesize methanol, and the resulting methanol product is sent to the methanol product receiving unit.

[0065] During the synthesis of methanol, purge gas, flash vapor, and first steam are generated. The first steam is sent to a steam header unit for collection. The purge gas and flash vapor are sent to a gas-fired boiler, which generates third steam, which is also sent to the steam header unit. The steam collected in the steam header is sent to a heat exchange unit to supplement the hot flue gas used for carbonizing biomass.

[0066] This embodiment is an overall design scheme for a biomass carbonization pretreatment system coupled with green methanol production.

[0067] Example 2: like Figure 2As shown, this embodiment provides a biomass carbonization pretreatment system coupled with green methanol production.

[0068] After being crushed and screened in the pretreatment unit, the biomass raw material is sent to the carbonization pretreatment unit. At the same time, oxygen and nitrogen in the air are separated. The nitrogen is sent to the heat exchange unit. 80-90% of the carbonization tail gas generated during the carbonization process is used as inert protective gas and sent to the heat exchange unit through the tail gas circulation fan. After being heated, it generates hot flue gas to carbonize the biomass, reducing nitrogen consumption and operating costs. The remaining 10-20% of the carbonization tail gas is sent to the gas boiler unit through a branch of the tail gas circulation fan pipeline for combustion. After meeting the standards, it is sent to the chimney emission unit for discharge.

[0069] After the biochar is fed into the pulverizing system for biochar pulverization, it is sent to the gasification unit, where oxygen separated from the air is also sent to the gasification unit to gasify the biochar powder.

[0070] When biomass charcoal powder is gasified, it produces combustible gas, which is then sent to a syngas purification unit for purification.

[0071] The purified combustible gas is sent to the methanol synthesis unit to synthesize methanol, and the resulting methanol product is sent to the methanol product receiving unit. During the methanol synthesis process, purge gas and flash vapor are generated, and the purge gas and flash vapor are sent to the gas boiler for combustion.

[0072] Steam generated by the gas-fired boiler is sent to a heat exchange unit to produce hot flue gas, which carbonizes the biomass. Meanwhile, condensate generated by the heat exchange unit is sent to the gas-fired boiler for water supply. Finally, the flue gas generated by the gas-fired boiler is sent to the chimney emission unit for treatment and discharge.

[0073] This embodiment is a preferred design scheme for a biomass carbonization pretreatment system coupled with green methanol production.

[0074] It should be noted that the components or devices mentioned in the embodiments of this application are all logical modules. Physically, a logical module can be a physical module, a part of a physical module, or a combination of multiple physical modules. The physical implementation of these logical modules themselves is not the most important factor; rather, the combination of functions implemented by these logical modules is the key to solving the technical problem proposed in this application. Furthermore, to highlight the innovative aspects of this application, the above-described system embodiments have not introduced components or devices that are not closely related to solving the technical problem proposed in this application. This does not mean that other components or devices do not exist in the above embodiments.

[0075] It should be noted that in the claims and description of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. It should also be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A biomass carbonization system coupled with methanol production, characterized in that, The system includes a biomass carbonization module, a methanol production module, and an air separation module, wherein... The biomass carbonization module includes: a crushing and screening pretreatment unit, a heat exchange unit, a carbonization pretreatment unit, and a tail gas circulation fan; wherein... The crushing and screening pretreatment unit includes: a biomass raw material inlet and a biomass outlet; The heat exchange unit includes: a gas inlet and a hot flue gas outlet; The carbonization pretreatment unit includes: a biomass feed inlet, a hot flue gas inlet, a biomass char outlet, and a carbonization tail gas outlet; The biomass outlet of the crushing and screening pretreatment unit is connected to the biomass inlet of the carbonization pretreatment unit. The hot flue gas outlet of the heating unit is connected to the hot flue gas inlet of the carbonization pretreatment unit via a pipeline. 80%-90% of the carbonization tail gas of the carbonization pretreatment unit is sent to the gas inlet of the heat exchange unit via a pipeline through a tail gas circulation fan. The methanol production module includes: a pulverizing unit, a gasification unit, a syngas purification unit, a methanol synthesis unit, and a methanol finished product receiving unit; wherein... The powder-making unit includes: a biochar inlet and a biochar powder outlet; The gasification unit includes: an oxygen inlet, a biomass charcoal powder inlet, and a combustible gas outlet; The syngas purification unit includes: a combustible gas inlet and a syngas outlet; The methanol synthesis unit includes: a synthesis gas inlet and a methanol product outlet; The methanol product receiving unit includes: a methanol product inlet; The biochar outlet of the carbonization pretreatment unit is connected to the biochar inlet of the pulverizing unit; the biochar powder outlet of the pulverizing unit is connected to the biochar powder inlet of the gasification unit; the combustible gas outlet of the gasification unit is connected to the combustible gas inlet of the syngas purification unit via a pipeline; the syngas outlet is connected to the syngas inlet via a pipeline; and the methanol product outlet of the methanol synthesis unit is connected to the methanol product inlet of the methanol product receiving unit via a pipeline. The air separation module includes: an air inlet, an oxygen outlet, and a nitrogen outlet. The oxygen outlet of the air separation module is connected to the oxygen inlet of the gasification unit via a pipeline, and the nitrogen outlet of the air separation module is connected to the gas inlet of the heating unit. After the air enters the air separation module, the oxygen and nitrogen are separated. The oxygen enters the gasification unit through the oxygen outlet via a pipeline, and the nitrogen enters the heating unit through the nitrogen outlet via a pipeline.

2. The biomass carbonization system coupled with methanol production as described in claim 1, characterized in that, The system also includes: a gas-fired boiler unit, a steam header unit, and a chimney emission unit, wherein... The gas-fired boiler unit includes: a venting gas and flash steam inlet, a third steam outlet, and a flue gas outlet; The steam header unit includes: a first steam inlet, a second steam inlet, a third steam inlet, and a steam outlet; The chimney emission unit includes a flue gas inlet; The methanol synthesis unit of the system also includes: a first steam outlet, a purge gas outlet, and a flash vapor outlet; The system vaporization unit further includes: a second steam outlet; The system heat exchange unit also includes a steam inlet; The steam outlet of the steam header unit is connected to the steam inlet of the heat exchange unit via a pipeline; the purge gas and flash steam outlets of the methanol synthesis unit are connected to the purge gas and flash steam inlets of the gas-fired boiler unit via pipelines; the flue gas outlet of the gas-fired boiler unit is connected to the flue gas inlet of the chimney emission unit via a pipeline; the first steam outlet of the methanol synthesis unit is connected to the first steam inlet of the steam header unit via a pipeline; the second steam outlet of the gasification unit is connected to the second steam inlet of the steam header unit via a pipeline; and the third steam outlet of the gas-fired boiler unit is connected to the third steam inlet of the steam header unit via a pipeline.

3. The biomass carbonization system coupled with methanol production as described in claim 1, characterized in that, A closed scraper conveyor is provided between the carbonization pretreatment unit and the pulverizing unit to feed the biomass char outlet of the carbonization pretreatment unit into the biomass char inlet of the pulverizing unit. A pneumatic conveying system is provided between the pulverizing unit and the gasification unit to deliver the biochar powder from the biochar powder outlet of the pulverizing unit to the biochar powder inlet.

4. The biomass carbonization system coupled with methanol production as described in claim 1, characterized in that, The heat exchange unit further includes a condensate outlet; the gas boiler unit further includes a condensate inlet; wherein the condensate outlet of the heat exchange unit is connected to the condensate inlet of the gas boiler unit via a pipe.

5. The biomass carbonization system coupled with methanol production as described in claim 1, characterized in that, The gas-fired boiler unit of the system also includes: a carbonization tail gas inlet; The pipeline that sends 80%-90% of the carbonization tail gas from the carbonization pretreatment unit to the gas inlet of the heat exchange unit via the tail gas circulation fan also includes a branch line. The branch line delivers 10%-20% of the carbonization tail gas to the carbonization tail gas inlet of the gas-fired boiler unit, and a pump valve is installed between the branch line and the main pipeline.

6. The biomass carbonization system coupled with methanol production as described in claim 1, characterized in that, The system also includes safety interlocking devices, which include: process parameter over-limit interlocking devices and equipment operating status interlocking devices.

7. The biomass carbonization system coupled with methanol production as described in claim 1, characterized in that, The system also includes integration with public systems.

8. The biomass carbonization system coupled with methanol production as described in claim 6, characterized in that, The utility system includes a nitrogen system, a circulating cooling water system, a compressed air system, and an electrical system.

9. A method for biomass carbonization coupled with methanol production, characterized in that, Includes the following steps: S1. Separate nitrogen and oxygen from the air to obtain oxygen and nitrogen; S2. The nitrogen obtained in step S1 and the carbonization tail gas generated during the carbonization of 80%-90% of biomass are heat-exchanged with the steam in the steam header to generate hot flue gas and condensate. S3. The hot flue gas obtained in step S2 is subjected to carbonization pretreatment together with the crushed and screened biomass to prepare biochar. Then the biochar is pulverized to prepare biochar powder. S4. The oxygen obtained in step S1 and the biomass char powder obtained in step S3 are fed into the gasification unit for gasification treatment to prepare combustible gas and second steam. S5. After purifying the combustible gas obtained in step S4, methanol is synthesized to prepare methanol, first vapor, purge gas and flash vapor. S5. The condensate obtained in step S3 is sent to the gas boiler for water supply. The carbonization tail gas from 10%-20% of the biomass carbonization, the release gas obtained in step S5, and the flash steam are sent to the gas boiler for combustion. The tail gas is discharged after meeting the standards, and the third steam is prepared at the same time.

10. The method as described in claim 8, characterized in that, The steam preparation for the steam header includes the following steps: N1, the first vapor generated during methanol synthesis; N2, the second steam generated during the gasification of recycled biomass charcoal powder; N3, the third steam generated when the carbonization tail gas, purge gas and flash steam of 10%-20% biomass carbonization are sent to the gas-fired boiler for combustion. N4. The steam recovered in steps N1, N2, and N3 is sent to the steam header to prepare the steam for the steam header.

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