A system and method for producing methanol / saf synthesis gas by multi-mode biomass staged directional gasification

Abstract

This invention discloses a system and method for producing methanol / SAF syngas through multi-mode biomass graded directional gasification, comprising: a double-cylinder gasifier with a coaxial sleeve structure, wherein an annular cavity is formed between the inner cylinder and the outer furnace shell to constitute a cooling and alkali-catching unit; the inner cylinder is arranged from top to bottom as a carbonization section, a functional reaction section, and a gasification section, each section having an independent gas distribution device; a subcritical water purification unit; a tail gas combustion and heating unit; and an ash and slag treatment and recycling unit; providing three types and six furnace types through modular configuration: Type I two-stage furnace for main syngas production, Type II three-stage furnace for deep syngas upgrading, and Type III two-stage furnace for co-producing carbon materials and dynamic activation; the method includes raw material matching, graded directional gasification, annular channel cooling and alkali catching at 550-650℃, tar graded purification, multi-stage energy recovery, and ash and slag recycling; this invention achieves zero waste by controlling alkali metals through a three-stage process of "source fixation - annular channel collection - subcritical water washing" and utilizing all components of ash and slag for resource utilization.

Description

Technical Field

[0001] This invention belongs to the field of biomass energy and green chemical technology, specifically relating to a biomass gasification system and method for producing methanol and / or sustainable aviation fuel (SAF) syngas, and particularly a multi-mode staged directional gasification system that can be flexibly configured according to the characteristics of the raw materials and product requirements. Background Technology

[0002] With the advancement of global "dual carbon" goals, the demand for green liquid fuels is surging. Biomass gasification to produce methanol and sustainable aviation fuel (SAF) can achieve carbon emission reductions of over 85%, making it one of the most promising technological pathways.

[0003] Biomass gasification is a thermochemical process that converts biomass into syngas under limited oxygen supply conditions. Current technologies largely follow the traditional coal gasification design paradigm, failing to fully consider the fundamental differences between biomass and coal in terms of elemental composition, volatile matter content, ash fusion point, and alkali metal occurrence forms, resulting in the following core bottlenecks: 1. Poor raw material adaptability: Biomass ash melting points vary significantly (1100-1350℃), and tar content can differ by several times. Existing furnace designs are fixed and cannot flexibly switch ash discharge modes (solid / molten) according to raw material characteristics, nor do they have a graded purification scheme configured according to tar content differences.

[0004] 2. Alkali metal corrosion slagging and tar-alkali metal synergistic deposition: Biomass has a much higher alkali metal content than coal, which easily precipitates at high temperatures to form low-melting-point eutectics. Simultaneously, tar and alkali metals mix in the 400-500℃ temperature range to form a difficult-to-remove conductive hard scale. Existing curing agent methods and high-temperature alloying methods both have shortcomings, lacking a multi-stage synergistic control system of "source fixation – process capture – end-of-pipe purification".

[0005] 3. Low energy utilization efficiency and low ash resource utilization: The overall thermal efficiency of the system is generally less than 50%, the cooling method of high-temperature moving parts is crude, and ash is mostly disposed of as waste.

[0006] 4. Insufficient system flexibility: The product structure is simple and lacks the flexible production capacity of "one source, multiple outputs".

[0007] The present invention aims to overcome the above-mentioned technical bottlenecks and provide a novel gasification system and method with flexible multi-mode configuration, efficient control of alkali metals, tar classification treatment, energy cascade utilization and resource recycling. Summary of the Invention

[0008] A system for multi-mode biomass staged directional gasification to produce methanol / SAF syngas includes: Double-cylinder gasifier: It adopts a coaxial sleeve structure, consisting of an outer furnace shell and an inner cylinder coaxially disposed within it. An annular cavity is formed between the inner cylinder and the outer furnace shell, serving as an annular channel for cooling and alkali-collecting. The internal space of the inner cylinder is arranged from top to bottom as a carbonization section, a functional reaction section, and a gasification section, each section equipped with an independent gas distribution device. Syngas is discharged through the gas outlet at the top of the annular cavity.

[0009] Subcritical water purification unit: The air inlet is connected to the gas outlet and is used for deep purification of the syngas.

[0010] Exhaust gas combustion heating unit: The inlet is connected to the purge gas outlet of the downstream synthesis unit, and the outlet is connected to the steam inlet of the double-cylinder gasifier.

[0011] Ash and slag treatment and circulation unit: The inlet is connected to the slag discharge port of the double-cylinder gasifier and the ash discharge port of the annular channel cooling and alkali removal unit, and the outlet is connected to the raw material pretreatment unit.

[0012] The system provides three types of furnaces through modular configuration: Type I: Main syngas production furnace (two-stage furnace for carbonization and gasification, with options for solid or molten slag discharge); Type II syngas deep upgrading furnace (with the addition of a mid-stage activation section and integration of a four-channel activation gas preparation device, forming a three-stage furnace of carbonization-activation-gasification). Type III co-production carbon material furnace (spiral or rake type two-stage dynamic furnace for carbonization and activation).

[0013] II. Methodology and Scheme A method for preparing methanol / SAF synthesis gas using the above system includes: 1. Raw material compatibility: Biomass raw materials are mixed with mineral flux inhibitors and high-melting-point recycled ash to control the ash melting point; 2. Staged directional gasification: The upper carbonization section is filled with superheated steam for low-temperature carbonization; the middle section utilizes a high-temperature activated coke layer or activated gas to achieve tar cracking and alkali metal fixation; the lower section is filled with a mixture of pure oxygen and steam as a gasifying agent to complete gasification. 3. Annular channel cooling and alkali capture: The temperature of the annular cavity is controlled at 550-650℃ to condense and capture gaseous alkali metals. 4. Tar grading and purification: Select either single-stage subcritical water purification or two-stage purification (external reforming + subcritical water) based on the tar content of the raw material; 5. Multi-stage energy recovery: cascade heat recovery is achieved through inner cylinder cooling, outer furnace shell jacket, exhaust gas combustion, and integrated cooling of high-temperature components, with complete self-sufficiency in steam; 6. Ash and slag recycling: Extract potassium fertilizer and return the high-melting-point components to step 1 for recycling.

[0014] III. Beneficial Effects 1. Tar Classification Treatment: Purification paths are configured according to the different tar contents. Low-tar operation saves approximately 10 million RMB in investment (for a 50,000-ton / year methanol project). Total tar removal rate > 99.9%, effluent tar < 0.5 mg / Nm³. 3 .

[0015] 2. Three-stage alkali metal control (80%-90% source fixation + 80%-90% annular channel capture + subcritical water washing >99%), with a total removal rate >99.9%, avoiding the 400-500℃ tar viscosity temperature range, eradicating the co-deposition problem.

[0016] 3. Four-stage energy cascade utilization: The system thermal efficiency is increased from the traditional 45%-50% to over 64%, and can reach 78% when E / F type furnaces co-produce carbon materials, with 100% self-sufficiency in steam.

[0017] 4. Resource utilization of all components of ash and slag: extract potassium fertilizer (K2O≥20%), and recycle high-melting-point components as fluxing agents to achieve "zero waste".

[0018] 5. Modular and Multi-Production: Three types of six furnaces can be flexibly switched to produce syngas, upgrade materials, or co-produce carbon materials. The E / F type furnace co-produces high-quality activated carbon (specific surface area ≥1500m²). 2 / g), carbon materials account for up to 60.7% of revenue.

[0019] 6. Long equipment life: The integrated cooling structure controls the wall temperature of the high-temperature zone below 400℃, and the expected life of the equipment is 15-20 years, which is 1-2 times longer than the traditional method. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the Type A furnace (slag melting mode) of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of the Type B furnace (solid slag mode) of the present invention.

[0022] Figure 3 This is a schematic diagram of the structure of the C-type furnace (three-stage solid slag) of the present invention.

[0023] Figure 4 This is a schematic diagram of the structure of the D-type furnace (three-section slag) of the present invention.

[0024] Figure 5 This is a schematic diagram of the structure of a public steam drum.

[0025] Figure 6 This is a schematic diagram of a four-channel activated gas preparation device.

[0026] Figure 7 This is a schematic diagram of the structure of the E-type furnace (spiral type) of the present invention.

[0027] Figure 8 This is a bottom view of the spiral blade half-pipe cooling unit 271A.

[0028] Figure 9 for Figure 8 Enlarged view of part A in the middle.

[0029] Figure 10 for Figure 8 Enlarged view of section B in the middle.

[0030] Figure 11 This is a schematic diagram of the structure of the F-type furnace (rake type) of the present invention.

[0031] Figure 12 This is a schematic diagram of the structure of the activation section (rake type).

[0032] Figure 13 for Figure 11 Enlarged view of section C.

[0033] Figure 14 for Figure 11 Enlarged view of section D in the middle.

[0034] Figure 15 This is a schematic diagram of the cooling system for the rake arm of a rake furnace.

[0035] Figure 16 This is a bottom view of the rake-type shelf half-pipe cooling unit 271B.

[0036] Figure 17 This is a system connection diagram.

[0037] Figure 18 This is a schematic diagram of a steam superheating system.

[0038] Figure 19 This is a schematic diagram of a three-tube swirl distribution device.

[0039] Figure 20 This is a schematic diagram showing the γ-angle of the vaporizing agent nozzle rotation.

[0040] Figure 21 This is a schematic diagram showing the rotation angle β of the vaporizing agent nozzle.

[0041] Figure 22 This is a schematic diagram showing the α-angle of the vaporizing agent nozzle rotation. Detailed Implementation

[0042] I. Overall System Composition The system of this invention includes: a staged directional reaction unit, a ring-channel cooling and alkali removal unit, a subcritical water purification unit, a tail gas combustion and heating unit, an ash and slag treatment and circulation unit, and a supporting steam power and process gas preparation unit. The system achieves complete steam self-sufficiency through multi-stage energy recovery, achieves a total removal rate >99.9% through three-stage alkali metal control, and achieves an outlet tar content <0.5 mg / Nm³ through tar staged treatment. 3 .

[0043] II. Hierarchical Directional Reaction Unit This unit adopts a coaxial sleeve furnace body structure as a general platform and provides three types of modular furnace configurations.

[0044] 2.1 General structural features (see Figure 1 , Figure 2 ) The furnace body is a coaxial sleeve-type pressure vessel, including: Inner cylinder (201): Vertical cylindrical shape, made of 310S or Incoloy 625, with a temperature resistance of ≥1200℃, its inner cavity forms the main reaction channel. The bottom of the inner cylinder is open, forming a furnace bottom gas collecting cavity (202) with the bottom of the lower reaction zone. The outer wall of the inner cylinder is welded with a spiral cooling channel (2011) for introducing cooling steam.

[0045] Outer furnace shell (203): Coaxially sleeved on the outside of the inner cylinder, made of Q345R or 310S, with a design pressure of 0.1-3.0MPa. An annular cavity (204) is formed between the outer furnace shell and the inner cylinder, with a gap width of 100-300mm.

[0046] Gas flow path: The cracked gas generated in the upper reaction zone descends to the bottom gas collecting chamber (202) and mixes with the gasified gas or activated gas generated in the lower reaction zone; the mixed gas turns back and rises into the annular cavity (204) for buffering, pressure stabilization and gravity settling; the clean crude synthesis gas is discharged from the gas outlet (205) at the top of the annular cavity.

[0047] 2.2 Segmented water jacket structure of the outer furnace shell (see...) Figure 5 ) The outer furnace shell (203) is equipped with an integrated water jacket, which is divided into two sections and connected in parallel with the combustion chamber semi-pipe strip jacket (145) to the common steam drum (121): Upper section: Water tank jacket (231), corresponding to the carbonization section, full water volume structure, connected to the steam drum through riser pipe (1211a) and downcomer pipe (1212a).

[0048] Lower section: Half-pipe vertical jacket (232), corresponding to the gasification section / activation section, is welded from a vertical half-pipe (2321), with the lower header (2322) and upper header (2323) at both ends, and then connected to the steam drum through the riser pipe (1211b) and the downcomer pipe (1212b).

[0049] Combustion chamber semi-pipe strip jacket (145): Located on the outer wall of the combustion chamber of the four-channel activated gas preparation device (140), and connected to the steam drum through the riser pipe (1451) and the downcomer pipe (1452).

[0050] The public steam drum (121) has a working pressure of 0.5 to 1.3 MPa and is equipped with a saturated steam outlet (1213), a feedwater inlet (1214), a level gauge (1215), and a safety valve (1216) to achieve a coordinated natural circulation of the three heat sources.

[0051] 2.3 Common Core Components: A three-tube swirl distribution device (see...) Figure 19-22 ) All furnace types employ a three-tube swirl distribution device (210) in the key gas distribution section. Multiple gas distribution units (211) are evenly arranged along the circumference of the furnace body. Each unit consists of an inner ring nozzle (2111), a middle ring nozzle (2112), and an outer ring nozzle (2113). The outlet ends of the three nozzles are equipped with guide vanes with different swirl angles: α (horizontal tangential angle) is 15°±2°, β (vertical upward tilt angle) is 30°±2°, and γ (vertical downward tilt angle) is 45°±2°. Multiple layers are arranged along the height direction, with adjacent gas distribution layers having opposite swirl directions (odd-numbered layers rotate left-handed, even-numbered layers rotate right-handed), forming a three-dimensional staggered turbulent mixing field.

[0052] 2.4 Reaction Section Division (see...) Figure 1 , 2 3, 7, 11) The inner cylinder (201) is arranged from top to bottom as follows: (a) Upper low-temperature carbonization section (221 / 231 / 241): Height 2-9m, operating temperature 500-650℃, high-temperature superheated steam of 800-1000℃ is introduced for biomass pyrolysis and carbonization.

[0053] (b) Mid-section functional reaction section: 5-7m high, operating temperature 800-1100℃, composed of high-temperature porous activated coke. This coke layer is rich in natural catalytic components such as calcium, magnesium, silicon, and aluminum, achieving in-situ tar cracking and in-situ chemical fixation of alkali metals without the need for external catalysts. Different furnace types have different implementation methods: Type I furnaces (Types A and B) do not have independent activation gas distribution; Types II and III furnaces (Types C, D, E, and F) have independent activation sections with activated gas introduced.

[0054] (c) Lower gasification section (222 / 233): Height 3-5m, operating temperature 900-1150℃ (solid slag mode) or >1200℃ (molten slag mode). A rotary grate (2222) and slag discharge port (solid slag mode) are provided at the bottom, and a gas distribution device (2221) is provided on the side wall (molten slag mode). The slag discharge method is controlled by adjusting the oxygen / steam ratio.

[0055] 2.5 Cooling and Heat Recovery System Inner cylinder half-pipe spiral cooling channel (2011): the inlet is connected to medium-pressure saturated steam (0.5-2.5MPa, 180-250℃), and the outlet is connected to the recovery steam manifold (2012), which preheats the saturated steam to 300-600℃ (first-stage energy recovery).

[0056] Outer furnace shell jacket and combustion chamber half-pipe jacket: The inlet is connected to the boiler feedwater or steam drum downcomer, and the outlet steam-water mixture is returned to the common steam drum (second-level energy recovery).

[0057] The steam recovery manifold (2012) collects preheated steam and sends it to the steam superheating system (133) for further heating to 800-1000℃ for reuse.

[0058] 2.6 Specific structural configurations of the three types of furnaces Category I: Main syngas production furnace type (two-stage furnace) Type B furnace (solid slag mode, standard): Adopts a general structure, with a solid slag mode in the lower gasification section, operating temperature <1150℃, and solid slag discharge. Suitable for high ash melting point raw materials (wood chips, nutshells, etc.).

[0059] Type A furnace (slag melting mode, optional): Based on Type B, the lower section is changed to slag melting mode, with an operating temperature >1200℃. It is equipped with a slag melting pool (2223) and a liquid slag discharge port (2224), and is suitable for low ash melting point raw materials (straw, etc.).

[0060] Category II: Syngas Deep Upgrading Furnace (Three-Stage Furnace) Type C furnace (solid slag mode): Based on the Type B furnace, an intermediate activation section is added between the carbonization section and the gasification section. It is equipped with a multi-layer three-tube swirl distribution device (210), which is connected to the outlet of a four-channel activation gas preparation device (140) through an insulated pipe. The activation gas temperature is 1000-1200℃, and the CO2 / H2O volume ratio is adjustable from 1:9 to 6:4.

[0061] Type D furnace (slag melting mode): Based on the Type A furnace, an intermediate activation section is added, with the same configuration as the Type C furnace, and the lower section maintains the slag melting mode.

[0062] Category III: Co-production carbon material furnace type (dynamic activation two-stage furnace) Type E furnace (dynamic spiral type, see below) Figure 7 , 8): Coaxial sleeve structure, upper carbonization section (241), lower activation section (242A). The top of the central shaft (2421A) is driven by a geared motor (2421A-1) with a speed of 0.1-5 rpm; the spiral blades (2422A) are continuously welded with a blade inclination angle of 25-45° and a pitch of 300-600 mm. The activation gas distribution device (2423) is equipped with a multi-layer three-tube swirl distribution device (210), which is connected to the four-channel activation gas preparation device (140) through the activation gas main pipe (2423-1). The furnace bottom is equipped with a carbon discharge mechanism (2424), including a water-cooled spiral discharge machine (2424-1), an activated carbon cooler (2424-2), and a finished product silo (2424-3).

[0063] Type F furnace (dynamic rake type, see below) Figure 11 , 12 The activation section (242B) adopts a central shaft rake-type multi-chamber structure. The central shaft (2421B) rotates at 0.05-3 rpm; the multi-layer rake arms (2422B) are axially layered with a layer spacing of 700-1800 mm. Each layer of rake arms is radially distributed and has rake teeth (2423B) fixed at the end, maintaining a gap of 5-10 mm with the furnace bottom or inner wall.

[0064] 2.7E / F type furnace integrated cooling structure (see Figure 15 , 16 ) Type E and Type F furnaces operate under extreme conditions of 1000-1200℃ and are equipped with two sets of synergistic cooling structures: (1) Central shaft double-tube double-cylinder cooling structure: suitable for central shaft cooling of E-type and F-type furnaces. It includes an inner tube (261 / 251) and an outer ring tube (262 / 252). The inner tube transports low-temperature saturated cooling steam (180-250℃, 0.5-1.3MPa). The upper part of the inner tube is connected to a low-temperature rotary joint, and the lower part is equipped with a sealing element and a drainage hole (267 / 257). The outer ring tube collects high-temperature superheated steam. The upper part is equipped with a sealing element, and the lower part is connected to a high-temperature rotary joint and a return hole (268 / 258). For F-type furnaces, each layer of rake arm (2422B) is equipped with an inner rake arm tube (251a) and an outer rake arm ring tube (252a), which are connected to the drainage hole (257) and the return hole (258) respectively. The rake teeth (2423B) are equipped with micro channels.

[0065] (2) Parallel half-pipe grouped cooling structure for spiral blades (270A): for spiral blades of type E furnace (2422A). The spiral blade is divided into N groups (N≥2, preferably 4-8 groups) of cooling units (271A) from top to bottom. Each group is equipped with a low-temperature saturated steam collection box (272) at the top, which is connected to the inner tube drainage hole (267) of the central shaft; each group is equipped with a high-temperature superheated steam collection box (273) at the bottom, which is connected to the outer ring tube return hole (268) of the central shaft. Multiple concentric parallel half-pipes (R5-R70mm) are welded on the surface or back of the spiral blade to form a closed flow channel.

[0066] (3) Rake-type shelf grouping cooling structure (270B): for F-type furnace rake-type shelves. The shelf is divided into N groups of cooling units (271B) from top to bottom. Involute spiral half-pipes (R5-R70mm) are welded on the surface or back of the shelf to form spiral cooling channels (274B). The two ends of the channel are connected to the drainage hole (257') and the return hole (258') respectively.

[0067] Cooling medium flow: Medium-pressure saturated steam enters the inner pipe → is distributed to each cooling unit through the diversion hole → flows through the parallel half pipe / involute spiral half pipe / rake arm inner pipe to absorb heat from the equipment → is heated to 300-600℃ superheated steam → flows into the outer ring pipe through the return hole → is sent to the recovery steam manifold (2012) → is sent to the steam superheating system (133) and superheated to 800-1000℃ → is reused as carbonization steam or activation gas conditioning gas.

[0068] III. Steam Power and Process Gas Preparation Unit (100) 3.1 Multi-stage waste heat boiler system (110): including a first-stage (113), a second-stage (112), and a third-stage (111) waste heat boiler, which sequentially recover the sensible heat of the crude syngas discharged from the gas outlet (205) to produce saturated steam at 180±20℃.

[0069] 3.2 Common Steam Drum System (120): The common steam drum (121) has a working pressure of 0.5-1.3MPa. The riser and fallr pipes of the upper section water tank type jacket (231), the lower section half pipe vertical jacket (232), and the combustion chamber half pipe strip jacket (145) are connected in parallel.

[0070] 3.3 Four-channel activation gas preparation device (140) (see) Figure 6The coaxial nested four-ring burner consists of, from the inside out, a central ignition channel (141), a fuel gas channel (142), a pure oxygen channel (143), and a conditioning gas channel (144). The conditioning gas channel is supplied with 800-1000℃ superheated steam from the steam superheating system (133). The outlet ends of the first and second rings form an oxygen-deficient combustion chamber, generating high-temperature flue gas >1400℃. This flue gas is then subjected to forced convection cooling and chemical conditioning by the high-speed injection of conditioning gas from the third ring. By adjusting the ratio of the three gas streams, the outlet process gas temperature is precisely controlled at 1000-1200℃, and the CO2 / H2O volume ratio is continuously adjustable from 1:9 to 6:4.

[0071] 3.4 Steam Buffer and Distribution System (130): The steam buffer tank (131) maintains a stable pressure of 0.5±0.05MPa. The steam distribution station (132) is divided into three routes: the first route reduces the pressure to 150-250℃ and sends it to the gasification section; the second route sends it to the equipment cooling steam pipeline network (1322); and the third route enters the steam superheating system (133). The steam superheating system includes a superheated burner (1331) and a shell-and-tube superheater (1332), which superheats the steam to 800-1000℃.

[0072] IV. Annular Channel Cooling and Alkali-Collecting Unit The inner wall of the annular cavity (204) is provided with circumferential trapezoidal or triangular ash-collecting ribs (rib height 10-30mm, spacing 50-150mm), and equipped with a pulse backflushing system (0.6-0.8MPa) and / or a strong magnetic scraper brush as an online ash-cleaning mechanism. By adjusting the cooling medium flow rate of the inner cylinder semi-pipe spiral cooling channel (2011) and the outer furnace shell jacket, the gas temperature and wall temperature in the annular cavity are precisely controlled at 550-650℃, so that the gaseous alkali metal precipitates out and is captured in solid powder form. The bottom ash discharge port is connected to the ash and slag treatment unit.

[0073] V. Subcritical Water Purification Unit The main body is a jacketed horizontal screw conveyor reactor (300), made of 316L / duplex steel, with a design pressure ≥20MPa. It has 3-5 sets of atomizing nozzles (301) along the axial direction, with an atomized particle size of 50-200μm and a screw speed of 0.5-5rpm. The working process is as follows: crude syngas first enters the jacket layer (temperature reduced to 400-500℃), is compressed to 3-17MPa, and then enters the reactor, where it comes into countercurrent contact with subcritical water preheated to 250-350℃. Operating conditions: temperature 250-350℃, pressure 3-17MPa, water-to-gas ratio 0.2-0.3, residence time 10-30 seconds. The tar content of the purified syngas at the outlet is <0.5mg / Nm³. 3 Alkali metal content < 0.1 mg / Nm 3 .

[0074] VI. Exhaust Gas Combustion Heating Unit The combustion chamber inlet receives downstream exhaust gas and is equipped with a porous swirl low-NOx burner with an air coefficient of 1.05-1.20, producing high-temperature flue gas at 1000-1200℃. The flue gas flows sequentially through the radiant section (producing saturated steam at 150-250℃), the convection section (superheating to 300-600℃), and the economizer (preheating boiler feedwater to 80-100℃), finally superheating the steam to 900±50℃ and sending it back to the gasifier.

[0075] VII. Ash and Slag Treatment and Recycling Unit High-temperature ash slag is cooled to <100℃ by a water-cooled screw conveyor and then enters a separation unit, where it is separated into potassium-containing components and high-melting-point components through physical sorting or chemical leaching. The potassium-containing components are concentrated by evaporation, crystallization, and drying to obtain potassium fertilizer (K2O≥20%). The high-melting-point components (CaO 15-30%, SiO2 30-50%, Al2O3 10-25%, ash melting point ≥1300℃) enter the circulating ash slag bin and are returned to the raw material pretreatment unit for recycling as a fluxing agent.

[0076] VIII. A method for producing methanol / SAF syngas through multi-mode staged directional gasification of biomass. Step 1: Raw material compatibility and pretreatment Biomass raw materials are crushed and dried to a particle size ≤50mm and a moisture content ≤15%, then mixed with high-melting-point recycled ash and mineral flux inhibitors. The Al / Si molar ratio is adjusted to >0.42, and the CaO / (Al2O3+SiO2) molar ratio is 0.3-0.5, so that the ash melting point is ≥1200℃ (solid slag mode) or ≥1300℃ (molten slag mode). The flux inhibitor and recycled ash are added at 5-30% each.

[0077] Step 2: Three-stage staged directional gasification Upper carbonization section: Introduce superheated steam at 800-1000℃, maintain temperature at 500-650℃, and hold for 30-60 minutes.

[0078] Mid-stage functional reaction section: For Class II / Class III furnaces, 1000-1200℃ activation gas (CO2 / H2O=1:9~6:4) is introduced, the temperature is 800-1000℃, and the residence time is 4-10 seconds; for Class I furnaces, pyrolysis gas is used to contact and crack the activated coke layer.

[0079] Lower gasification section: Pure oxygen and steam at 150-250℃ are introduced, with an oxygen-to-carbon ratio of 0.2-0.4 and a steam-to-carbon ratio of 0.5-1.0. The temperature is 900-1150℃ (solid slag) or >1200℃ (molten slag), and the residence time is 15-30 minutes.

[0080] Step 3: Cooling and alkali-collecting in the annular channel Control the temperature of the annular cavity to 550-650℃, achieve a collection efficiency of 80-90%, and clean the ash regularly.

[0081] Step 4: Tar Grading Processing Choose between single-stage subcritical water purification or two-stage purification (external high-temperature reforming + subcritical water) based on the tar content of the raw material.

[0082] Step 5: Multi-stage energy recovery and steam closed-loop The system achieves four-stage utilization through inner cylinder half-pipe cooling, outer furnace shell jacket, exhaust gas combustion, and integrated cooling, with a thermal efficiency of ≥64%.

[0083] Step 6: Ash and Slag Treatment and Recycling The gasification ash residue is mixed and separated with the ash collected in the annular channel to extract potassium fertilizer, and the high-melting-point components are returned to step 1.

[0084] Step 7 (applicable to Type III furnaces): Co-production of carbon materials Start the central shaft drive mechanism, with the screw shaft rotating at 0.1-5 rpm or the rake shaft at 0.05-3 rpm, and introduce activation gas to directionally prepare a specific surface area ≥1500 m². 2 / g of activated carbon. Simultaneously, an integrated cooling structure is used to recover heat.

[0085] IX. Examples The following examples are based on measured data from an industrial demonstration device that has been running continuously for more than 720 hours, and energy balance has been ensured through thermal calculations.

[0086] Example 1: Type B furnace (Class I solid slag mode) for treating forestry waste Furnace specifications: Total height 19m, inner diameter Φ3.6m, carbonization section height 9m, gasification section height 5m, annular cavity gap 200mm.

[0087] Raw materials: pine wood chips, dry basis processing capacity 8.5t / h, lower heating value 18.2MJ / kg, moisture content 12%.

[0088] Consumption and Products: Alkali metal control: Source fixation rate 88.5%, annular channel collection rate 87.2%, alkali metal concentration at outlet after subcritical water washing 0.08 mg / Nm³ 3 The overall removal rate was 99.94%. The purified tar content was 0.27 mg / Nm³. 3 .

[0089] Slag mode (Type A furnace) optional configuration: When processing low ash melting point raw materials, switch to Type A furnace, operating temperature >1200℃, increase pure oxygen per ton of raw material by about 9%, alkali metal source fixation rate by about 82.5%, potash fertilizer production increased by about 129% (165kg / h), effective gas concentration 93.7%, thermal efficiency 63.8%.

[0090] Example 2: Processing high-tar mixed feedstock using a C-type furnace (Type II three-stage upgrading) Furnace specifications: Total height 22m, inner diameter Φ3.6m, carbonization section height 8m, activation section height 6m, gasification section height 5m.

[0091] Raw materials: Mixed raw materials (50% corn stalks + 50% sawdust), processing capacity 7.5t / h, lower heating value 17.5MJ / kg, moisture content 10%.

[0092] Four-channel activation gas parameters: fuel gas 380 Nm 3 / h, pure oxygen 420Nm 3 / h, conditioning steam 1850kg / h (920℃), outlet activation gas 1085℃, CO2 / H2O≈1:1.

[0093] Consumption and Products: Tar: 625 mg / Nm³ at the carbonization section outlet 3 After activation, the concentration dropped to 320 mg / Nm³. 3 Subcritical water concentration: 0.31 mg / Nm³ 3 The total removal rate of alkali metals was 99.76%.

[0094] Slag mode (D-type furnace) optional configuration: When processing low ash melting point high tar raw materials, switch to D-type furnace, which increases pure oxygen per ton of raw material by about 12%, alkali metal source fixation rate by about 94.8%, potash fertilizer production by about 110%, and thermal efficiency by 63.5%.

[0095] Example 3: Processing walnut shells using an E-type furnace (Class III gas-coke co-production). Furnace specifications: Total height 19m, inner diameter Φ3.6m, carbonization section height 10m, activation section height 9m, screw shaft pitch 400mm, rotation speed 0.8rpm. Integrated cooling: medium-pressure saturated steam 3200kg / h (210℃), outlet temperature 495℃.

[0096] Raw material: walnut shells, processing capacity 5.0 t / h, lower heating value 19.0 MJ / kg, moisture content 8%.

[0097] Four-channel activation gas: 380 Nm of pure oxygen 3 / h, conditioning steam 1680kg / h (920℃), outlet 1085℃.

[0098] Consumption and Products: Activated carbon: specific surface area 1520m² 2 / g, iodine adsorption 1180mg / g, methylene blue 210mg / g, strength 92%.

[0099] Example 4: F-type furnace (Class III rake type) for processing coconut shells Furnace specifications: Total height 19m, inner diameter Φ3.6m, rake shaft speed 1.2rpm, layer spacing 1200mm, 6 rake arms per layer. Integrated cooling: Steam 2800kg / h, outlet temperature 502℃.

[0100] Raw material: coconut shell, processing capacity 4.8t / h, lower heating value 18.8MJ / kg, moisture content 10%.

[0101] Four-channel activation gas: 350 Nm of pure oxygen 3 / h, conditioning steam 1550kg / h (920℃), outlet 1090℃, CO2 / H2O=1.2:1.

[0102] Consumption and Products: Activated carbon: specific surface area 1560m² 2 / g, iodine adsorption 1220mg / g, methylene blue 225mg / g, strength 91.5%.

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for producing methanol / SAF syngas through multi-mode staged directional gasification of biomass, characterized in that, include: The double-cylinder gasifier adopts a coaxial sleeve structure, including an outer furnace shell and an inner cylinder coaxially disposed inside it; an annular cavity is formed between the inner cylinder and the outer furnace shell, which constitutes an annular channel cooling and alkali-collecting unit; the internal space of the inner cylinder is arranged from top to bottom as a carbonization section, a functional reaction section and a gasification section, and each section is equipped with an independent gas distribution device; the syngas is discharged through the gas outlet at the upper part of the annular cavity; A subcritical water purification unit, whose air inlet is connected to the gas outlet, is used for deep purification of syngas; The exhaust gas combustion heating unit has its inlet connected to the vent gas outlet of the downstream synthesis unit, and its outlet connected to the steam inlet of the double-cylinder gasifier. The ash and slag treatment and circulation unit has its inlet connected to the slag discharge port of the double-cylinder gasifier and the ash discharge port of the annular channel cooling and alkali-collecting unit, and its outlet connected to the raw material pretreatment unit.

2. The system according to claim 1, characterized in that, The system provides three types of furnaces through modular configuration: Type I is a syngas-producing furnace, which is a two-stage furnace for carbonization and gasification, and has two modes: solid slag discharge or molten slag discharge. The Type II syngas deep upgrading furnace is a three-stage furnace consisting of a Type I furnace with the addition of a mid-stage activation section and an integrated four-channel activation gas preparation device, forming a carbonization-activation-gasification process. Type III co-production carbon material furnaces include spiral carbonization-activation two-stage furnaces and rake carbonization-activation two-stage furnaces.

3. The system according to claim 1, characterized in that, The outer furnace shell is equipped with an integrated water jacket segmented along the height direction: the upper segment is a water tank type jacket, corresponding to the carbonization section; the lower segment is a semi-pipe vertical jacket, corresponding to the gasification section or activation section; the combustion chamber outer wall of the four-channel activation gas preparation device is equipped with a semi-pipe strip jacket; the water tank type jacket, the semi-pipe vertical jacket and the semi-pipe strip jacket are connected in parallel to the same common steam drum, forming a multi-heat source coordinated steam and water natural circulation system.

4. The system according to claim 1, characterized in that, All furnace types employ a swirl distribution device consisting of at least three pipes per set in the key gas distribution section. The device includes multiple gas distribution units evenly arranged around the furnace body. Each gas distribution unit consists of an inner ring nozzle, a middle ring nozzle, and an outer ring nozzle. The outlet ends of the three nozzles are equipped with guide vanes with different swirl angles. Multiple layers are arranged along the height of the furnace body, and the swirl directions of adjacent gas distribution layers are opposite.

5. The system according to claim 2, characterized in that, The four-channel activation gas preparation device in the Type II syngas deep upgrading furnace is a coaxial nested four-ring burner, including a central ignition channel, a fuel gas channel, a pure oxygen channel, and a conditioning gas channel; the conditioning gas channel is used to introduce superheated steam from the steam superheating system; by adjusting the airflow ratio of each channel, the outlet process gas temperature is controlled at 1000-1200℃, and the CO2 / H2O volume ratio is continuously adjustable from 1:9 to 6:

4.

6. The system according to claim 2, characterized in that, The spiral or rake-type carbonization-activation two-stage furnace in the Class III co-production carbon material furnace type is equipped with an integrated cooling structure, including: a central axis double-tube double-cylinder cooling structure, and a semi-tube group cooling structure set on the spiral blade or rake arm plate; the central axis double-tube double-cylinder cooling structure consists of an inner tube and an outer ring tube arranged coaxially, the inner tube is connected to the cooling steam source and has a diversion hole, and the outer ring tube is connected to the recovery steam manifold and has a return hole; the semi-tube group cooling structure includes multiple independent cooling units, the inlet of each unit is connected to the diversion hole, and the outlet is connected to the return hole. The cooling medium is distributed to each cooling unit through the inner tube and the diversion hole to absorb heat, and then flows into the outer ring tube for recovery through the return hole.

7. The system according to claim 1, characterized in that, The annular channel cooling and alkali-catching unit includes: circumferential ash-catching ribs set on the inner wall of the annular cavity, and an online ash-removing mechanism; through the coordinated cooling of the inner cylinder cooling channel and the outer furnace shell jacket, the gas temperature and wall temperature in the annular cavity are controlled at 550-650℃, so that the gaseous alkali metals are selectively precipitated in solid form and captured.

8. The system according to claim 1, characterized in that, The subcritical water purification unit includes a jacketed horizontal spiral feeder reactor; the inlet of the jacket layer of the reactor is connected to the gas outlet of the annular channel cooling and alkali-collecting unit for recovering the sensible heat of the syngas; multiple sets of atomizing nozzles are arranged axially inside the reactor for spraying subcritical water; the operating temperature inside the reactor is 250-350℃, the operating pressure is 3-17MPa, the water-to-gas volume ratio is 0.2-0.3, and the syngas residence time is 10-30 seconds; the gas phase outlet of the reactor is connected to the downstream synthesis unit.

9. The system according to claim 1, characterized in that, The ash and slag treatment and recycling unit includes: a separation device for separating mixed ash and slag into potassium-containing components and high-melting-point components; an alkali metal extraction device for extracting potassium fertilizer from the potassium-containing components; and a recycling ash and slag bin for storing the high-melting-point components and returning them to the raw material pretreatment unit for recycling as a fluxing agent.

10. A method for preparing methanol / SAF synthesis gas using the system according to any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: Raw material compatibility. Mix biomass raw materials with mineral flux inhibitors and high-melting-point recycled ash, and adjust the ash melting point to the target range. Step 2: Staged directional gasification. In the carbonization section, superheated steam is introduced for low-temperature carbonization; in the middle section, a high-temperature activated coke layer or activation gas is introduced to achieve tar cracking and alkali metal fixation; in the lower section, a gasification agent of pure oxygen and steam is introduced to complete the gasification, and solid or molten slag is discharged according to the furnace type; when using a Class III furnace type, solid carbon material is collected at the end of the activation section. Step 3: Cooling and capturing alkali in the annular channel, controlling the temperature of the annular cavity at 550-650℃, so that the gaseous alkali metal condenses, precipitates and is captured; Step 4: Tar grading and purification. Depending on the tar content of the raw material, either single-stage subcritical water purification or two-stage purification of external reforming and subcritical water is selected. Step 5: Multi-stage energy recovery, through the cooling of the inner cylinder, the outer furnace shell jacket, the combustion of the exhaust gas and the integrated cooling of high-temperature components, to achieve cascade heat recovery, and the superheated steam produced is completely self-sufficient and reused in the gasification process; Step 6: Ash and slag recycling. Potassium fertilizer is extracted from the ash and slag, and the high-melting-point components are returned to Step 1 for recycling.

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