System and method for the production of sustainable aviation fuel

Abstract

The application discloses a preparation system and method of sustainable aviation fuel, comprising at least one distributed pyrolysis unit and one centralized gasification and synthesis unit; the distributed pyrolysis unit comprises a pyrolysis reactor and a condensation oil collecting device connected in sequence, the pyrolysis reactor is used for pyrolyzing household garbage into pyrolysis gas, the condensation oil collecting device is used for condensing the pyrolysis gas into pyrolysis oil, and the non-condensable gas outlet of the condensation oil collecting device is connected with the gas inlet of the pyrolysis reactor; the centralized gasification and synthesis unit comprises a gasification furnace, a synthesis gas purifier, a Fischer-Tropsch synthesis reactor and a rectifying column connected in sequence, the gasification furnace is connected with the condensation oil collecting device and is used for conveying the pyrolysis oil into the gasification furnace for gasification; the synthesis gas outlet of the gasification furnace is connected with the synthesis gas purifier, and the synthesis gas purifier is used for removing CO2 in the synthesis gas; the Fischer-Tropsch synthesis reactor is used for preparing the synthesis gas into Fischer-Tropsch oil, and the rectifying column is used for processing the Fischer-Tropsch oil into sustainable aviation fuel, so that the carbon conversion rate and the yield of the sustainable aviation fuel are improved.

Description

Technical Field

[0001] This invention relates to the field of solid waste disposal, and in particular to a system and method for preparing sustainable aviation fuel. Background Technology

[0002] Sustainable aviation fuel (SAF), due to its "zero-carbon / low-carbon" attributes and compatibility with existing infrastructure and power equipment, has become a key pathway for deep decarbonization in this field. Among different SAF preparation routes, using municipal solid waste as raw material and producing SAF through gasification and Fischer-Tropsch synthesis is one of the few routes that can currently compete with the mature HEFA (hydrogenation of esters and fatty acids) process. However, in existing technologies, such as patent JP2023011306A, a method for producing synthetic fuel is disclosed, which directly gasifies the raw material and performs Fischer-Tropsch synthesis to obtain SAF. However, this method not only results in a low carbon conversion rate in the gasification reaction but also reduces the yield of SAF. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the sustainable aviation fuel preparation routes in the prior art, and to provide a sustainable aviation fuel preparation system and method.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] This invention provides a sustainable aviation fuel preparation system, which includes at least one distributed pyrolysis unit and one centralized gasification synthesis unit;

[0006] The distributed pyrolysis unit includes a pyrolysis reactor and a condensation and oil collection device. The pyrolysis reactor is used to pyrolyze municipal solid waste to obtain pyrolysis gas. The pyrolysis gas outlet of the pyrolysis reactor is connected to the condensation and oil collection device, which is used to condense the pyrolysis gas into pyrolysis oil. The non-condensable gas outlet of the condensation and oil collection device is connected to the gas inlet of the pyrolysis reactor.

[0007] The centralized gasification synthesis unit includes a gasifier, a syngas purifier, a Fischer-Tropsch synthesis reactor, and a distillation column. The feed inlet of the gasifier is connected to the condensate oil collection device for conveying pyrolysis oil to the gasifier for gasification. The syngas outlet of the gasifier is connected to the gas inlet of the syngas purifier, which removes CO2 from the syngas. The syngas purifier has a purified gas outlet and a CO2 outlet. The CO2 outlet is connected to the feed inlet of the gasifier, and the purified gas outlet of the syngas purifier is connected to the gas inlet of the Fischer-Tropsch synthesis reactor. The Fischer-Tropsch oil outlet of the Fischer-Tropsch synthesis reactor is connected to the feed inlet of the distillation column, which processes the Fischer-Tropsch oil into sustainable aviation fuel.

[0008] In this scheme, the CO2 outlet of the syngas purifier is connected to the feed inlet of the gasifier. By reinjecting the CO2 separated by the syngas purifier into the feed inlet of the gasifier, not only can CO2 react with C to generate CO, increasing the SAF yield per unit of raw material, but the temperature inside the gasifier can also be adjusted by controlling the proportion of reinjected CO2, thus preventing the gasifier from becoming dangerous due to excessive temperature.

[0009] Preferably, when there are multiple distributed pyrolysis units, multiple condensation and oil collection devices are connected to the feed inlet of the gasifier to transport the pyrolysis oil from the multiple distributed pyrolysis units to the gasifier for gasification.

[0010] Preferably, the centralized gasification synthesis unit further includes a waste heat boiler and a sulfur-resistant shift reactor. The synthesis gas outlet of the gasifier is connected to the synthesis gas inlet of the sulfur-resistant shift reactor through the waste heat boiler. The steam inlet of the sulfur-resistant shift reactor is also connected to the steam outlet of the waste heat boiler. The synthesis gas outlet of the sulfur-resistant shift reactor is connected to the gas inlet of the synthesis gas purifier.

[0011] In this embodiment, a waste heat boiler recovers and utilizes the waste heat of syngas to generate steam, and the steam is fed into a sulfur-resistant shift reactor to carry out a water-gas shift reaction to adjust the molar ratio of H2 / CO, thereby improving the stability of the feedstock ratio entering the Fischer-Tropsch synthesis reactor and thus improving the stability of SAF quality.

[0012] Preferably, when the raw material for the gasifier also includes biochar, the centralized gasification synthesis unit further includes a coal mill, which is used to grind the pyrolysis oil and biochar into a slurry, and the outlet of the coal mill is connected to the inlet of the gasifier.

[0013] In this scheme, through co-grinding and pulping, biochar particles can be uniformly suspended in the carrier pyrolysis oil, thereby making the slurry exhibit shear refinement characteristics, which can solve the problems of pumping difficulties and atomization coking, and can also utilize the alkali metals of biochar to neutralize the acid corrosion of pyrolysis oil.

[0014] Preferably, the pyrolysis reactor includes a rotary kiln and a pyrolysis char incineration reactor. The pyrolysis char incineration reactor is integrally disposed at the tail end of the rotary kiln. The upper part of the pyrolysis char incineration reactor is provided with a pyrolysis char inlet, and the bottom includes a rotating grate. The rotating grate is also provided with a central pipe, which serves as the gas inlet of the pyrolysis reactor for introducing the gaseous raw material required for combustion in the pyrolysis char incineration reactor.

[0015] Preferably, the rotary kiln is provided with a pyrolysis gas outlet, which is connected to the condensate oil collection device via a cyclone dust collector, and the pyrolysis carbon outlet of the cyclone dust collector is connected to the pyrolysis carbon inlet of the pyrolysis carbon incineration reactor.

[0016] Preferably, the condensation and oil collection device includes a condenser, an oil-water separator, and an electrostatic precipitator. The condensate outlet of the condenser is connected to the oil-water separator, and the non-condensable gas outlet of the condenser is connected to the electrostatic precipitator. The electrostatic precipitator is used to collect residual pyrolysis oil in the non-condensable gas. The non-condensable gas outlet of the electrostatic precipitator is connected to the gas inlet of the pyrolysis reactor and the flue gas purification device, respectively.

[0017] In this scheme, flue gas recirculation not only reduces the amount of flue gas to be disposed of, but also lowers the combustion temperature of the pyrolytic char layer. This ensures complete combustion of the pyrolytic char while reducing dioxins and NOx emissions. x The generation of harmful and acidic gases.

[0018] Preferably, the flue gas purification device includes a waste heat recovery unit for recovering the waste heat of the non-condensable gas, and the hot air outlet of the waste heat recovery unit is connected to the gas inlet of the pyrolysis reactor.

[0019] This invention also provides a method for preparing sustainable aviation fuel, using the sustainable aviation fuel preparation system described in any one of the above claims, comprising the following steps:

[0020] S1. Domestic waste is fed into the pyrolysis reactor to undergo pyrolysis reaction to obtain pyrolysis gas. The pyrolysis gas is condensed into pyrolysis oil by the condenser oil collection device, and the non-condensable gas separated from the condenser oil collection device is recycled to the pyrolysis reactor to provide energy for the pyrolysis reaction.

[0021] S2. The pyrolysis oil, gasifying agent, and CO2 recycled from the syngas purifier to the gasifier are mixed and fed into the gasifier to carry out a gasification reaction to obtain syngas. The syngas is then sent to the syngas purifier to remove CO2 to obtain purified gas. Then, Fischer-Tropsch oil is produced through Fischer-Tropsch synthesis reaction and further processed into sustainable aviation fuel through distillation.

[0022] The preparation method preferably uses one or more of the following conditions:

[0023] The vaporizing agent is pure oxygen or air;

[0024] When the pyrolysis reactor includes a rotary kiln and a pyrolysis char incineration reactor, the reaction temperature of the rotary kiln is 300℃-600℃.

[0025] The residence time of the rotary kiln is 0.5h-1.5h;

[0026] The air equivalence ratio required for combustion in the pyrolysis char incineration reactor is 0.1-0.3;

[0027] After the non-condensable gas is circulated, the combustion temperature of the pyrolytic carbon incineration reactor is 850℃-900℃.

[0028] The temperature of the gasification reaction is 1200℃-1600℃;

[0029] The pressure of the gasification reaction inside the gasifier is 1MPa-5MPa;

[0030] The molar ratio of H2 to CO in the synthesis gas is 0.7-1.0;

[0031] The CO2 circulation rate is 30%-50% of the CO2 removed from the syngas purifier;

[0032] The reaction temperature inside the Fischer-Tropsch synthesis reactor is 200℃–240℃;

[0033] The reaction pressure inside the Fischer-Tropsch synthesis reactor is 2.1 MPa-2.4 MPa.

[0034] The preparation method preferably uses one or more of the following conditions, wherein the raw materials for the pyrolysis reaction also include a dechlorinating agent, and the mass ratio of the dechlorinating agent to the municipal solid waste is 1%-10%;

[0035] The dechlorinating agent is one of CaO, CaCO3, Na2CO3 or NaHCO3;

[0036] The pressure of the gasification reaction inside the gasifier is 2.1 MPa-2.4 MPa.

[0037] Preferably, the mass ratio of the dechlorinating agent to the municipal solid waste is 3%.

[0038] Preferably, in step S2: the raw material for the gasifier further includes biochar, and before the gasification reaction begins, the following steps are also included: the pyrolysis oil and biochar are mixed and ground into an oil-carbon slurry by a coal mill, and the oil-carbon slurry, gasifying agent and CO2 recycled from the syngas purifier to the gasifier are mixed and fed into the gasifier.

[0039] Before removing CO2 from the syngas, the process includes the following steps: recovering heat from the syngas through a waste heat boiler and sending the heated steam to a sulfur-resistant shift reactor to adjust the H2 / CO molar ratio in the syngas.

[0040] The preparation method preferably uses one or more of the following conditions:

[0041] The biochar is straw charcoal and / or wood chip charcoal;

[0042] The biochar accounts for less than 40% of the mass of the oil charcoal slurry;

[0043] The sulfur-resistant shift reactor is used to adjust the molar ratio of H2 / CO in the synthesis gas to 1.8-2.1;

[0044] The reaction temperature inside the sulfur-resistant shift reactor is 200℃-250℃;

[0045] The reaction pressure inside the sulfur-resistant shift reactor is 1 MPa-5 MPa;

[0046] The outlet temperature of the crude syngas from the waste heat boiler is 200℃-250℃.

[0047] The preparation method preferably uses one or more of the following conditions:

[0048] The biochar accounts for 10%-30% of the mass of the oil char slurry;

[0049] The reaction pressure inside the sulfur-resistant shift reactor is 2.1 MPa-2.4 MPa.

[0050] The positive and progressive effects of this invention are as follows:

[0051] 1. By preparing pyrolysis oil through a decentralized pyrolysis unit for municipal solid waste and transporting the pyrolysis oil to a centralized gasification synthesis unit to prepare sustainable aviation fuel, not only is the carbon conversion rate of the gasification reaction improved, thereby increasing the production of SAF, but the contradiction between distributed municipal solid waste disposal and large-scale Fischer-Tropsch synthesis is also resolved. This achieves large-scale, low-cost preparation of SAF while meeting the carbon emission reduction requirements of SAF.

[0052] 2. By reinjecting CO2 into the pressurized gasifier, not only is local overheating suppressed and the gasifier temperature distribution made uniform, but the recovered CO2 can also be used to react with carbon to generate CO, thereby increasing the yield of SAF per unit of raw material.

[0053] 3. By recovering waste heat through a waste heat recovery unit and feeding steam into a sulfur-resistant shift reactor, the molar ratio of H2 / CO in the gasification gas can be adjusted, thereby improving the stability of product quality.

[0054] 4. By using oil-carbon slurry mixed gasification, the alkali metals of biochar can neutralize the acidic corrosion of pyrolysis oil, preventing the pyrolysis oil from corroding the equipment; it can also maintain suspension stability and pumping viscosity, making the atomized particles of the gasification nozzle small and uniform, thereby improving the carbon conversion rate.

[0055] 5. By mixing domestic waste and dechlorinating agents, in-situ dechlorination through pyrolysis is achieved. At the same time, combined with flue gas recirculation, the generation of dioxins, NOx, and acidic gases is reduced, thereby reducing the cost of flue gas treatment. Furthermore, the waste heat of the flue gas can be used to power the pyrolysis reaction, further reducing the cost of the pyrolysis reaction.

[0056] 6. By integrating the internally heated rotary pyrolysis reactor with the pyrolysis char incineration reactor, the system footprint and operating costs are reduced. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the structure of a distributed pyrolysis unit in a system for preparing SAF from municipal solid waste according to an embodiment of the present invention.

[0058] Figure 2 This is a schematic diagram of the structure of a centralized gasification synthesis unit in a system for preparing SAF from municipal solid waste according to an embodiment of the present invention.

[0059] Explanation of reference numerals in the attached figures:

[0060] Pyrolysis reactor 1

[0061] Rotary kiln 1001

[0062] 1002 Pyrolysis Carbon Incineration Reactor

[0063] Rotary grate 1003

[0064] Central tube 1004

[0065] Cyclone dust collector 2

[0066] Condenser 3

[0067] Oil-water separator 4

[0068] Electrostatic precipitator 5

[0069] Wet deacidification unit 6

[0070] Catalytic oxidation reactor 7

[0071] SCR denitrification reactor 8

[0072] Waste heat recovery unit 9

[0073] Dust collector 10

[0074] Coal mill 11

[0075] Air Separator 12

[0076] Gasifier 13

[0077] Waste heat boiler 14

[0078] Sulfur-resistant shift reactor 15

[0079] Syngas Purifier 16

[0080] Fischer-Tropsch synthesis reactor 17

[0081] Distillation column 18

[0082] CO2 purification reactor 19 Detailed Implementation

[0083] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0084] Example 1

[0085] like Figure 1-2 As shown, this embodiment provides a sustainable aviation fuel preparation system, which includes 10 distributed pyrolysis units and 1 centralized gasification synthesis unit.

[0086] In this embodiment, the distributed pyrolysis unit includes a pyrolysis reactor 1 and a condensation and oil collection device. The pyrolysis gas outlet of the pyrolysis reactor 1 is connected to the condensation and oil collection device. The pyrolysis reactor 1 includes an internally heated rotary kiln 1001 and a pyrolysis char incineration reactor 1002. The pyrolysis char incineration reactor 1002 is integrally installed at the tail end of the internally heated rotary kiln 1001. After preliminary crushing, the municipal solid waste is fed into the internally heated rotary kiln 1001 for pyrolysis. The heat required for the pyrolysis reaction is provided by the high-temperature flue gas generated by the pyrolysis of char in the integrated pyrolysis char incineration reactor 1002 at the tail end of the internally heated rotary kiln 1001. The pyrolysis char in the pyrolysis char incineration reactor 1002 is generated by the pyrolysis of the municipal solid waste in the internally heated rotary kiln 1001, and the pyrolysis char generated by the pyrolysis of municipal solid waste is transported from the tail end of the internally heated rotary kiln 1001 to the pyrolysis char incineration reactor 1002. A rotary grate 1003 is provided at the bottom of the pyrolysis char incineration reactor 1002 to achieve uniform distribution of the pyrolysis char layer and discharge of slag within the pyrolysis char incineration reactor 1002. A central pipe 1004 is also provided in the rotary grate 1003, which serves as the gas inlet of the pyrolysis reactor 1002 for introducing the gaseous raw material required for incinerating the pyrolysis char.

[0087] In this embodiment, the pyrolysis gas outlet of the internally heated rotary kiln 1001 is connected to a condensation and oil collection device via a cyclone dust collector 102. The cyclone dust collector 102 is used to remove pyrolysis char and dust from the pyrolysis gas output from the pyrolysis gas outlet of the internally heated rotary kiln 1001. The pyrolysis char outlet of the cyclone dust collector 102 is connected to the pyrolysis char inlet of the pyrolysis char incineration reactor 1002, and is used to transport the pyrolysis char separated from the pyrolysis gas back to the pyrolysis char incineration reactor 1002 for incineration, thereby providing energy for the pyrolysis reaction of municipal solid waste.

[0088] In this embodiment, municipal solid waste, after preliminary crushing, is mixed with dechlorinating agent CaO and fed into an internally heated rotary kiln 1001 for pyrolysis reaction, achieving in-situ dechlorination through pyrolysis, thereby controlling dioxins and NO. x The formation of pollutants such as...

[0089] In other embodiments, the dechlorination agent may also be CaCO3, Na2CO3, or NaHCO3.

[0090] In this embodiment, the condensation and oil collection device includes a condenser 3, an oil-water separator 4, and an electrostatic precipitator 5. The gas inlet of the condenser 3 is connected to the gas outlet of the cyclone dust collector 102, the condensate outlet of the condenser 3 is connected to the oil-water separator 4, and the non-condensable gas outlet of the condenser 3 is connected to the gas inlet of the electrostatic precipitator 5. The pyrolysis gas after dust removal is condensed by spraying to obtain condensate. The obtained condensate is separated into pyrolysis oil and wastewater by the oil-water separator 4, and the pyrolysis oil is further stored. The non-condensable gas output from the non-condensable gas outlet of the condenser 3 is further collected as pyrolysis oil product by the electrostatic precipitator 5.

[0091] In this embodiment, the non-condensable gas outlet of the electrostatic precipitator 5 is connected to the central pipe 1004 of the bottom rotating grate 1003 in the pyrolytic carbon incineration reactor 1002. Through flue gas recirculation, not only is the amount of flue gas to be disposed of reduced, but the combustion temperature of the pyrolytic carbon layer is also lowered. This ensures complete combustion of the pyrolytic carbon while reducing dioxins and NOx. x The generation of harmful and acidic gases.

[0092] In this embodiment, the distributed pyrolysis reaction unit also includes a non-condensable gas purification device, the gas inlet of which is connected to the non-condensable gas outlet of the electrostatic precipitator 5.

[0093] In this embodiment, the non-condensable gas purification device includes a wet acid desulfurization unit 6, a catalytic oxidation reactor 7, an SCR denitrification reactor 8, a waste heat recovery unit 9, and a dust collector 10 connected in sequence. The wet acid desulfurization unit 6 is connected to the non-condensable gas outlet of the electrostatic precipitator 5 and is used to remove HCl and SO from the non-condensable gas. x Acidic gases. Catalytic oxidation reactor 7 is used to remove combustible components such as CO and H2 from non-condensable gases, and to increase the temperature of the non-condensable gases by catalytic oxidation of these combustible components. SCR denitrification reactor 8 is used to remove NO from flue gas. x The waste heat recovery unit 9 is used to recover the waste heat of non-condensable gas to heat air. The hot air outlet of the waste heat recovery unit 9 is connected to the hot air inlet of the catalytic oxidation reactor 7 and the central tube 1004 of the rotary grate 1003, respectively. The non-condensable gas outlet of the waste heat recovery unit 9 is also connected to the dust collector 10, through which dioxins and dust in the non-condensable gas are removed.

[0094] In this embodiment, the wet deacidifier 6 removes HCl and SO from the non-condensable gas by spraying. x The acidic gas is sprayed with NaOH solution; the catalytic oxidation reactor 7 uses Pd / γ-Al2O3 honeycomb catalyst, and the temperature rise of the non-condensable gas is provided by the catalytic oxidation of combustible gases such as CO or H2; the waste heat recovery unit 9 is a rotary air preheater, and the dust collector 10 is a bag dust collector with activated carbon adsorption.

[0095] In other embodiments, the solution sprayed by the wet deacidifier 6 is a Ca(OH)2 solution or other alkaline solutions, and the catalytic reactor uses a Pd / γ-Al2O3 short-bed particulate catalyst.

[0096] In this embodiment, the centralized gasification synthesis unit includes a pressurized gasifier 13, a syngas purifier 16, a Fischer-Tropsch synthesis reactor 17, and a distillation column 18. The feed inlet of the pressurized gasifier 13 is connected to a condenser and oil collection device, and the syngas outlet of the pressurized gasifier 13 is connected to the gas inlet of the syngas purifier 16. In this embodiment, the connection between the feed inlet of the pressurized gasifier 13 and the condenser and oil collection device means that the pyrolysis oil collected by the condenser and oil collection device in the distributed pyrolysis unit is centrally stored, transported in batches to the centralized gasification synthesis station, and then fed to the feed inlet of the pressurized gasifier 13.

[0097] In other embodiments, the feed inlet of the pressurized gasifier 13 can also be directly connected to the condensation and oil collection device via a pipeline.

[0098] In this embodiment, the syngas purifier 16 includes a dust removal mechanism and an acid removal washing mechanism, used to remove impurities such as CO2, dust, and H2S from the syngas. This embodiment uses wet dust removal to remove dust from the syngas, and a low-temperature methanol washing coupled purification process can be used to remove acidic gases from the syngas. The purified gas outlet of the syngas purifier 16 is connected to the gas inlet of the Fischer-Tropsch synthesis reactor 17, and the CO2 outlet of the syngas purifier 16 is connected to the feed inlet of the pressurized gasifier 13, used to reinject the CO2 separated in the syngas purifier 16 into the pressurized gasifier 13. The Fischer-Tropsch oil outlet of the Fischer-Tropsch synthesis reactor 17 is connected to the feed inlet of the distillation column 18, which is used to process the Fischer-Tropsch oil into sustainable aviation fuel.

[0099] In this embodiment, the CO2 outlet of the syngas purifier 16 is connected to the feed inlet of the gasifier 13 through the CO2 purification reactor 19. The CO2 purification reactor 19 purifies the CO2 removed by the syngas purifier 16. A portion of the purified CO2 is pressurized by the compressor and then circulated back to the feed inlet of the gasifier 13, thereby reacting with C to generate CO, increasing the SAF yield per unit of raw material. Another portion of CO2 is transported out as a green CO2 product.

[0100] In this embodiment, a gas flow regulator is also provided at the CO2 outlet of the syngas purifier 16. The gas flow regulator can adjust the reinjection ratio of CO2 circulating from the CO2 outlet to the feed port of the pressurized gasifier 13.

[0101] In this embodiment, a coal mill 11 is also installed at the feed inlet of the pressurized gasifier 13. The coal mill 11 co-mills the pyrolysis oil and biochar to form a slurry. The oil-carbon slurry is then transported to the pressurized gasifier 13 for gasification reaction via a feed pump installed at the feed inlet. Through co-milling and slurry preparation, biochar particles with a particle size of less than 200 mesh can be uniformly suspended in the carrier pyrolysis oil, thereby giving the slurry shear refinement characteristics. This solves the problems of pumping difficulties and atomization coking, and also allows the alkali metals of the biochar to neutralize the acidic corrosion of the pyrolysis oil.

[0102] In this embodiment, the pressurized gasifier 13 is also equipped with a temperature sensor. The temperature sensor is connected to the gas flow regulator at the CO2 outlet of the syngas purifier 16 via a controller. When the temperature sensor detects that the furnace temperature of the pressurized gasifier 13 exceeds a preset value, the controller controls the gas flow regulator to increase the CO2 reinjection ratio, thereby reducing the temperature of the pressurized gasifier 13 through the endothermic reaction of CO2 and C, and preventing the pressurized gasifier 13 from causing danger due to excessive temperature.

[0103] In this embodiment, the centralized gasification synthesis unit also includes a waste heat boiler 14 and a sulfur-resistant shift reactor 15. The synthesis gas outlet of the gasifier 13 is connected to the synthesis gas inlet of the sulfur-resistant shift reactor 15 through the waste heat boiler 14. After recovering the heat from the synthesis gas, the waste heat boiler 14 uses the recovered heat to heat the water in the waste heat boiler 14 to generate steam, and then sends the steam through the steam outlet to the sulfur-resistant shift reactor 15, thereby carrying out a water-gas shift reaction in the sulfur-resistant shift reactor 15 to adjust the molar ratio of H2 / CO.

[0104] In this embodiment, an online gas analyzer is also installed at the CO2 outlet of the syngas purifier 16. The online analyzer is connected to a gas flow regulator installed at the steam outlet of the waste heat boiler 14 via a controller. The online gas analyzer detects the H2 / CO molar ratio at the syngas outlet of the sulfur-resistant shift reactor 15. The controller controls the gas flow regulator to increase or decrease the steam flow rate entering the sulfur-resistant shift reactor 15, thereby precisely adjusting the H2 / CO molar ratio at the syngas outlet of the sulfur-resistant shift reactor 15 through the water-gas shift reaction, thereby improving the stability of SAF product quality. When the online analyzer detects that the H2 / CO molar ratio at the syngas outlet is too low, the controller can also control the gas flow regulator at the CO2 outlet of the syngas purifier 16 to reduce the CO2 reinjection ratio.

[0105] This embodiment also provides a method for preparing sustainable aviation fuel, using the above-mentioned sustainable aviation fuel preparation system, including the following steps:

[0106] Municipal solid waste with a moisture content of 50%-55% is mixed with 3% (by weight) of dechlorinating agent and fed into pyrolysis reactor 1 for pyrolysis to produce pyrolysis gas. The pyrolysis char incineration reactor 1002, integrated at the tail end of pyrolysis reactor 1, has an incineration temperature of 870℃ and requires an air equivalence ratio of 0.2 for combustion. The pyrolysis gas is condensed into pyrolysis oil by a condensation and oil collection device, and the non-condensable gas separated from the condensation and oil collection device is recycled back to pyrolysis reactor 1 to supply energy for the pyrolysis reaction.

[0107] Pyrolysis oil and straw charcoal are co-ground into a slurry using a coal mill 11. This slurry is then mixed with pure oxygen (a gasifying agent) and CO2 recycled from the syngas purifier 16 to the gasifier 13, and fed into the pressurized gasifier 13 for gasification to produce syngas. The syngas is then transported to a waste heat boiler 14 to recover waste heat, and the syngas, cooled to 210°C after waste heat recovery, is fed into a sulfur-resistant shift reactor 15. In the waste heat boiler 14, the recovered heat is used to heat water to generate steam, which is then fed into the sulfur-resistant shift reactor 15. In the sulfur-resistant shift reactor 15, a water-gas shift reaction is carried out at a temperature of 210°C and a pressure of 2.2 MPa to adjust the molar ratio of H2 / CO in the syngas to 2.05. The syngas purifier 16 removes CO2 from the syngas to obtain purified gas, which is then fed into the Fischer-Tropsch reactor. The Fischer-Tropsch synthesis reaction is carried out at a temperature of 220°C and a pressure of 2.2 MPa to produce Fischer-Tropsch oil. The Fischer-Tropsch oil is then distilled through a distillation column 18 to separate the components with different boiling points, and the C8-C16 components are selected as SAF.

[0108] In other embodiments, the Fischer-Tropsch oil is subjected to distillation and hydrotreating or hydrocracking processes via distillation column 18, and the C8-C16 components in the Fischer-Tropsch oil are extracted as SAF.

[0109] The specific process parameters and effect data of Example 1 are shown in Tables 1-3 below.

[0110] In Example 1, 21.6 tons of municipal solid waste and 1.22 tons of straw charcoal can produce 6.1 tons of oil-charcoal slurry, and 6.1 tons of oil-charcoal slurry can produce 1 ton of SAF (Self-Activated Fume Extract), with a production cost of 9,000 yuan per ton of SAF. Furthermore, by adjusting the molar ratio of H2 / CO in the syngas through a water-gas shift reaction, not only is the selectivity of SAF increased to over 45%, but the cetane number in the oil is also higher, resulting in better combustion performance.

[0111] Example 2

[0112] The difference between Example 2 and Example 1 is that the sustainable aviation fuel preparation system in Example 2 does not include a coal mill 11, and no exogenous biochar and pyrolysis oil are added for co-grinding and pulping. The rest of the system and other process parameters are exactly the same as in Example 1. The specific process parameters and effect data of Example 2 are shown in Tables 1-3 below.

[0113] In Example 2, 33.6 tons of municipal solid waste raw materials can be used to produce 7.6 tons of biochar slurry, and 7.6 tons of biochar slurry can be used to produce 1 ton of SAF. Moreover, due to the lack of neutralizing effect of alkali metals in biochar, the acidic corrosion of the feed pump and other devices at the feed inlet of gasifier 13 is aggravated, resulting in a significant reduction in equipment life.

[0114] Comparative Example 1

[0115] Compared to Example 1, the sustainable aviation fuel preparation system of Comparative Example 1 does not include a distributed pyrolysis unit, but only a centralized gasification synthesis unit, and does not have a circulation pipeline for reinjecting CO2 gas into the feed inlet of the pressurized gasifier 13. The rest of the system is the same as that of Example 1.

[0116] The difference between the sustainable aviation fuel preparation method of Comparative Example 1 and the sustainable aviation fuel preparation method of Example 1 is that the municipal solid waste in Comparative Example 1 is not treated by a distributed pyrolysis unit. Instead, the municipal solid waste is crushed, magnetically separated, and dried to reduce the moisture content to below 20%. After being made into derived fuel (RDF), it is directly fed into the circulating fluidized bed gasifier 13 for gasification reaction, and CO2 is not reinjected into the feed inlet of the gasifier 13. Other steps and process parameters are the same as in Example 1. The specific process parameters and effect data of Comparative Example 1 are shown in Tables 1-3 below.

[0117] In Comparative Example 1, 35 tons of municipal solid waste raw materials can produce 1 ton of SAF. However, since Comparative Example 1 did not have a distributed pyrolysis unit, the pretreatment process of municipal solid waste was long and could not be produced on a large scale, which increased the production cost of each ton of SAF to 16,000 yuan.

[0118] Comparative Example 2

[0119] The difference between Comparative Example 2 and Example 1 is that the oil-carbon slurry ratio used in Comparative Example 2 is different from that in Example 1, but the system, steps, and other process parameters used in Comparative Example 2 are exactly the same as those in Example 1. The specific process parameters and effect data of Comparative Example 2 are shown in Tables 1-3 below.

[0120] In Comparative Example 2, 17.0 tons of municipal solid waste and 3.2 tons of straw charcoal can produce 7 tons of oil-charcoal slurry, and 7 tons of oil-charcoal slurry can produce 1 ton of SAF. Moreover, due to the excessively high solid content in the oil-charcoal slurry, the viscosity of the slurry increases significantly, which not only increases the load on the feed pump and causes pressure fluctuations, but also causes severe coking of the nozzles, reducing the atomization effect of the nozzles and resulting in incomplete local reactions within the gasifier 13.

[0121] Comparative Example 3

[0122] The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 does not have a circulation pipeline for reinjecting CO2 gas into the feed inlet of the pressurized gasifier 13. The rest of the system and other process parameters are exactly the same as in Example 1. The specific process parameters and effect data of Comparative Example 3 are shown in Tables 1-3 below.

[0123] In Comparative Example 3, 23.7 tons of municipal solid waste and 1.3 tons of straw charcoal can produce 6.7 tons of oil-charcoal slurry, and 6.7 tons of oil-charcoal slurry can produce 1 ton of SAF. Moreover, due to the lack of CO2 reinjection, local hot spots appeared in the gasifier 13, and the temperature uniformity deteriorated, which not only reduced the gasification reaction efficiency and thus the SAF yield, but also may have caused safety risks to the gasifier 13.

[0124] Comparative Example 4

[0125] The difference between Comparative Example 4 and Example 1 is that: in Comparative Example 4, the waste heat boiler 14 and the sulfur-resistant shift reactor 15 were not set up to adjust the molar ratio of H2 / CO in the syngas. The molar ratio of H2 / CO in the syngas was 0.8. The rest of the system and other process parameters were exactly the same as in Example 1.

[0126] In Comparative Example 4, because the molar ratio of H2 / CO in the syngas was not adjusted, only 0.4 tons of SAF could be produced from 6.1 tons of oil-carbon slurry. The product contained more oxygenated organic matter, the SAF selectivity was only 25%, the cetane number of the oil was lower than that of Example 1, and the combustion performance was worse than that of Example 1.

[0127] Table 1 Composition of Municipal Solid Waste

[0128]

[0129] Table 2 Pyrolysis reaction parameters

[0130]

[0131] Table 3 Gasification reaction parameters

[0132]

[0133] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A system for preparing sustainable aviation fuel, characterized in that, It includes at least one distributed pyrolysis unit and one centralized gasification synthesis unit; The distributed pyrolysis unit includes a pyrolysis reactor and a condensation and oil collection device. The pyrolysis reactor is used to pyrolyze municipal solid waste to obtain pyrolysis gas. The pyrolysis gas outlet of the pyrolysis reactor is connected to the condensation and oil collection device, which is used to condense the pyrolysis gas into pyrolysis oil. The non-condensable gas outlet of the condensation and oil collection device is connected to the gas inlet of the pyrolysis reactor. The centralized gasification synthesis unit includes a gasifier, a syngas purifier, a Fischer-Tropsch synthesis reactor, and a distillation column. The feed inlet of the gasifier is connected to the condensate oil collection device for conveying pyrolysis oil to the gasifier for gasification. The syngas outlet of the gasifier is connected to the gas inlet of the syngas purifier, which removes CO2 from the syngas. The syngas purifier has a purified gas outlet and a CO2 outlet. The CO2 outlet is connected to the feed inlet of the gasifier, and the purified gas outlet of the syngas purifier is connected to the gas inlet of the Fischer-Tropsch synthesis reactor. The Fischer-Tropsch oil outlet of the Fischer-Tropsch synthesis reactor is connected to the feed inlet of the distillation column, which processes the Fischer-Tropsch oil into sustainable aviation fuel.

2. The sustainable aviation fuel preparation system as described in claim 1, characterized in that, The centralized gasification synthesis unit also includes a waste heat boiler and a sulfur-resistant shift reactor. The synthesis gas outlet of the gasifier is connected to the synthesis gas inlet of the sulfur-resistant shift reactor through the waste heat boiler. The steam inlet of the sulfur-resistant shift reactor is also connected to the steam outlet of the waste heat boiler. The synthesis gas outlet of the sulfur-resistant shift reactor is connected to the gas inlet of the synthesis gas purifier. And / or, when the raw material for the gasifier also includes biochar, the centralized gasification synthesis unit further includes a coal mill, which is used to grind the pyrolysis oil and biochar into a slurry, and the outlet of the coal mill is connected to the inlet of the gasifier.

3. The sustainable aviation fuel preparation system as described in claim 1, characterized in that, The pyrolysis reactor includes a rotary kiln and a pyrolysis char incineration reactor. The pyrolysis char incineration reactor is integrally installed at the tail of the rotary kiln. The upper part of the pyrolysis char incineration reactor is provided with a pyrolysis char inlet, and the bottom includes a rotating grate. The rotating grate is also provided with a central pipe, which serves as the gas inlet of the pyrolysis reactor for introducing the gaseous raw material required for combustion in the pyrolysis char incineration reactor. The rotary kiln is provided with a pyrolysis gas outlet, which is connected to the condensation and oil collection device through a cyclone dust collector. The pyrolysis carbon outlet of the cyclone dust collector is connected to the pyrolysis carbon inlet of the pyrolysis carbon incineration reactor. And / or, the condensation and oil collection device includes a condenser, an oil-water separator, and an electrostatic precipitator. The condensate outlet of the condenser is connected to the oil-water separator, and the non-condensable gas outlet of the condenser is connected to the electrostatic precipitator. The electrostatic precipitator is used to collect residual pyrolysis oil in the non-condensable gas. The non-condensable gas outlet of the electrostatic precipitator is connected to the gas inlet of the pyrolysis reactor and a flue gas purification device, respectively. The flue gas purification device includes a waste heat recovery unit, which is used to recover the waste heat of the non-condensable gas. The hot air outlet of the waste heat recovery unit is connected to the gas inlet of the pyrolysis reactor.

4. A method for preparing sustainable aviation fuel, characterized in that, The system for preparing sustainable aviation fuel as described in any one of claims 1-3 includes the following steps: S1. Domestic waste is fed into the pyrolysis reactor to undergo pyrolysis reaction to obtain pyrolysis gas. The pyrolysis gas is condensed into pyrolysis oil by the condenser oil collection device, and the non-condensable gas separated from the condenser oil collection device is recycled to the pyrolysis reactor to provide energy for the pyrolysis reaction. S2. The pyrolysis oil, gasifying agent, and CO2 recycled from the syngas purifier to the gasifier are mixed and fed into the gasifier to carry out a gasification reaction to obtain syngas. The syngas is then sent to the syngas purifier to remove CO2 to obtain purified gas. Then, Fischer-Tropsch oil is produced through Fischer-Tropsch synthesis reaction and further processed into sustainable aviation fuel through distillation.

5. The method for preparing sustainable aviation fuel as described in claim 4, characterized in that, The vaporizing agent is pure oxygen or air; When the pyrolysis reactor includes a rotary kiln and a pyrolysis char incineration reactor, the reaction temperature of the rotary kiln is 300℃-600℃. The residence time of the rotary kiln is 0.5h-1.5h; The air equivalence ratio required for combustion in the pyrolysis char incineration reactor is 0.1-0.3; After the non-condensable gas is circulated, the combustion temperature of the pyrolytic carbon incineration reactor is 850℃-900℃. The temperature of the gasification reaction is 1200℃-1600℃; The pressure of the gasification reaction inside the gasifier is 1MPa-5MPa; The molar ratio of H2 to CO in the synthesis gas is 0.7-1.0; The CO2 circulation rate is 30%-50% of the CO2 removed from the syngas purifier; The reaction temperature inside the Fischer-Tropsch synthesis reactor is 200℃–240℃; The reaction pressure inside the Fischer-Tropsch synthesis reactor is 2.1 MPa-2.4 MPa.

6. The method for preparing sustainable aviation fuel as described in claim 4, characterized in that, The raw materials for the pyrolysis reaction also include a dechlorinating agent, and the mass ratio of the dechlorinating agent to the municipal solid waste is 1%-10%. The dechlorinating agent is one of CaO, CaCO3, Na2CO3 or NaHCO3; The pressure of the gasification reaction inside the gasifier is 2.1 MPa-2.4 MPa.

7. The method for preparing sustainable aviation fuel as described in claim 6, characterized in that, The mass ratio of the dechlorinating agent to the domestic waste is 3%.

8. The method for preparing sustainable aviation fuel as described in claim 4, characterized in that, In step S2: The raw materials for the gasifier also include biochar. Before the gasification reaction begins, the following steps are also included: mixing and grinding the pyrolysis oil and biochar into an oil-carbon slurry using a coal mill, and then mixing the oil-carbon slurry, gasifying agent, and CO2 recycled from the syngas purifier to the gasifier and feeding it into the gasifier. Before removing CO2 from the syngas, the process includes the following steps: recovering heat from the syngas through a waste heat boiler and sending the heated steam to a sulfur-resistant shift reactor to adjust the H2 / CO molar ratio in the syngas.

9. The method for preparing sustainable aviation fuel as described in claim 8, characterized in that, The biochar is straw charcoal and / or wood chip charcoal; The biochar accounts for less than 40% of the mass of the oil charcoal slurry; The sulfur-resistant shift reactor is used to adjust the molar ratio of H2 / CO in the synthesis gas to 1.8-2.1; The reaction temperature inside the sulfur-resistant shift reactor is 200℃-250℃; The reaction pressure inside the sulfur-resistant shift reactor is 1 MPa-5 MPa; The outlet temperature of the crude syngas from the waste heat boiler is 200℃-250℃.

10. The method for preparing sustainable aviation fuel as described in claim 9, characterized in that, The biochar accounts for 10%-30% of the mass of the oil char slurry; The reaction pressure inside the sulfur-resistant shift reactor is 2.1 MPa-2.4 MPa.

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