CN-121975545-A - Method and system for preparing green aviation kerosene by cooperation of biogas and lignin

CN121975545ACN 121975545 ACN121975545 ACN 121975545ACN-121975545-A

Abstract

The invention discloses a method and a system for preparing green aviation kerosene by combining marsh gas and lignin, wherein the method comprises the steps of carrying out ternary autothermal reforming reaction on the pretreated marsh gas and byproduct gas generated by hydrodeoxygenation of lignin to generate synthetic gas; one path of synthesis gas is subjected to Fischer-Tropsch synthesis reaction to generate Fischer-Tropsch synthesis oil mainly comprising straight-chain alkane, the other path of synthesis gas is used for producing high-purity hydrogen, the hydrogen reacts with pretreated lignin to generate aromatic-rich biological crude oil, the Fischer-Tropsch synthesis oil is blended with the aromatic-rich biological crude oil to obtain blend oil, and the blend oil is subjected to hydrofining and fractionation to obtain a green aviation kerosene product. The invention successfully realizes the efficient cooperative conversion of the biogas and the lignin through the multi-technology coupling and the system-level innovation, not only provides a reliable path for the large-scale production of the green aviation fuel, but also has obvious carbon emission reduction benefit and economic advantage.

Inventors

FAN LEI
XU GUOFENG
WANG JIANGTAO
GONG RUJING
WANG JIN
QI YU

Assignees

中海油石化工程有限公司

Dates

Publication Date: 20260505
Application Date: 20260202

Claims (10)

1. A method for preparing green aviation kerosene by combining biogas and lignin is characterized by comprising the following steps: S1, preprocessing a methane raw material and a lignin raw material; S2, hydrodeoxygenation is carried out on the lignin raw material pretreated in the step S1, byproduct gas generated by hydrodeoxygenation and the biogas raw material pretreated in the step S1 are fed into a plasma-assisted ternary reforming reactor together, steam and oxygen are fed into the reactor, a plasma ignition device is adopted for starting and stable combustion, and ternary autothermal reforming reaction is carried out in the presence of a multifunctional nickel-based reforming catalyst to generate synthesis gas; s3, dividing the synthesis gas generated in the step S2 into two paths according to a variable proportion, wherein the first path of synthesis gas is sent into a Fischer-Tropsch synthesis reactor to generate Fischer-Tropsch synthesis oil mainly containing linear alkane under the action of a Co-based catalyst; S4, introducing the high-purity hydrogen produced in the step S3 into a lignin catalytic depolymerization and hydrodeoxygenation reactor, and reacting with the lignin raw material pretreated in the step S1 under the action of a sulfide catalyst to generate aromatic hydrocarbon-rich biological crude oil; s5, blending the Fischer-Tropsch synthetic oil obtained by the Fischer-Tropsch synthetic reaction in the step S3 with the aromatic hydrocarbon-rich biological crude oil obtained in the step S4 to obtain blend oil; and S6, hydrofining and fractionating the blend oil obtained in the step S5 to finally obtain a green aviation kerosene product.
2. The method for preparing green aviation kerosene by combining marsh gas and lignin according to claim 1, wherein the pretreatment of the marsh gas raw material comprises desulfurization and desilication oxygen alkane purification treatment, and the specific method for the pretreatment of the marsh gas raw material comprises the following steps: S111, reducing the total sulfur content of the biogas to below 1 ppm by using chemical adsorption; S112, the desulfurized biogas raw material passes through a desilication oxygen alkane device filled with an adsorbent, and the total siloxane concentration in the biogas raw material is reduced to below 0.1 mg/m 3 ; the lignin raw material pretreatment comprises drying and crushing, and the specific method for the lignin raw material pretreatment comprises the following steps: s121, drying the lignin raw material to reduce the moisture content of the lignin raw material to below 5%; S122, crushing the dried lignin raw material to enable the particle size of the lignin raw material to be smaller than 2mm.
3. The method for preparing green aviation kerosene by combining biogas and lignin according to claim 1 is characterized in that the operation condition of the lignin hydrodeoxygenation is that the lignin raw material pretreated in the step S1 is subjected to hydrodeoxygenation reaction in a hydrogen atmosphere with the temperature of 280-380 ℃ and the pressure of 5-10 MPa in the presence of a hydrodeoxygenation catalyst.
4. The method for preparing green aviation kerosene by combining marsh gas and lignin according to claim 1, wherein the byproduct gas generated by hydrodeoxygenation of lignin raw material comprises the following components in percentage by volume: 10% -25% of carbon dioxide; 5% -35% of methane; 5% -15% of C1-C4 light hydrocarbon; 30% -50% of hydrogen.
5. The method for preparing green aviation kerosene by combining marsh gas and lignin according to claim 1, wherein the reaction temperature of the ternary autothermal reforming reaction is 750-850 ℃ and the pressure is 0.5-2.0 MPa; The circulation amount of the byproduct gas accounts for 5 wt% -15 wt% of the total feeding amount of the plasma auxiliary ternary reforming reactor; In the ternary autothermal reforming reaction, the molar ratio of the core components of the reaction raw materials in the plasma-assisted ternary reforming reactor is controlled to be CH 4 ：H 2 O：CO 2 ：O 2 =1 (0.5-0.7): 0.8-1): 0.4-0.6.
6. The method for preparing green aviation kerosene by combining marsh gas and lignin according to claim 1, wherein the molar flow distribution ratio of the first path of synthesis gas to the second path of synthesis gas is 7:3; the Fischer-Tropsch synthesis reactor has the reaction conditions that the temperature is 210-230 ℃ and the pressure is 2.0-2.5 MPa.
7. The method for preparing green aviation kerosene by combining marsh gas and lignin according to claim 1, wherein the method for producing high-purity hydrogen is characterized in that the second path of synthesis gas is introduced into a water gas shift reactor, the CO content in the second path of synthesis gas is reduced to be less than 1.0 vol% at the temperature of 250-350 ℃, then the second path of synthesis gas is introduced into a PSA unit for hydrogen extraction, the operating pressure of the PSA unit is 1.5-3.0 MPa, the desorption pressure is normal pressure to micro negative pressure, and hydrogen with the purity of more than 99.5% is obtained through 4-10 towers for cyclic operation.
8. The method for preparing green aviation kerosene by combining methane and lignin according to claim 1 is characterized in that the reaction conditions of the lignin catalytic depolymerization and hydrodeoxygenation reactor are that the temperature is 350-420 ℃, the pressure is 12-18 MPa, the hydrogen partial pressure is not lower than 8MPa, the mass flow ratio of hydrogen to lignin raw materials in the feed is (0.05-0.15): 1, and the sulfide catalyst is selected from a supported NiMo-S system or a supported CoMo-S system.
9. The method for preparing green aviation kerosene by combining biogas and lignin according to claim 1 is characterized in that the mass ratio of Fischer-Tropsch synthetic oil obtained by Fischer-Tropsch synthetic reaction in step S3 to aromatic-rich biological crude oil obtained by step S4 in the blend oil is (4-8): 1, and the aromatic content in the blend oil is 8-25 wt%.
10. A system for preparing green aviation kerosene by combining marsh gas and lignin according to the method of any one of claims 1 to 9 is characterized by comprising a raw material pretreatment unit, a ternary autothermal reforming reaction unit, a biological crude oil production unit, a Fischer-Tropsch synthesis unit, a hydrogen production unit, a product blending unit, a hydrofining and fractionating unit, an oxyhydrogen gas supply unit, a power supply unit and a waste heat utilization unit; The raw material pretreatment unit comprises a biogas pretreatment unit and a lignin pretreatment unit (16); the biogas pretreatment unit is connected with the ternary autothermal reforming reaction unit; The biogas pretreatment unit comprises a biogas purification unit (1) and a reforming section compressor (2) which are sequentially connected, and an outlet of the reforming section compressor (2) is connected with a ternary autothermal reforming reaction unit; The lignin pretreatment unit (16) is connected with the biological crude oil production unit, a byproduct gas outlet of the biological crude oil production unit is connected with the ternary self-heating reforming reaction unit, a biological crude oil outlet of the biological crude oil production unit is connected with the product blending unit (18), and the product blending unit (18) is connected with the hydrofining and fractionating unit; the ternary autothermal reforming reaction unit comprises a plasma-assisted ternary reforming reactor (3) and a plasma ignition device (4) arranged at the inlet of a combustion zone of the plasma-assisted ternary reforming reactor (3); the synthesis gas outlet of the ternary autothermal reforming reaction unit is connected with a synthesis gas distribution unit (6) through a waste heat utilization unit; One outlet of the synthesis gas distribution unit (6) is connected with the Fischer-Tropsch synthesis unit, and the other outlet is connected with the hydrogen production unit; the Fischer-Tropsch synthesis unit comprises a Fischer-Tropsch synthesis reactor (7) and a Fischer-Tropsch product separator (8) which are connected in sequence, wherein a C5+ alkane fraction outlet of the Fischer-Tropsch product separator (8) is connected with a product blending unit (18); The hydrogen production unit comprises a water gas shift reactor (9) and a PSA hydrogen purification unit (13) which are connected in sequence, wherein a hydrogen outlet of the PSA hydrogen purification unit (13) is connected with a hydrogen buffer tank (14) of the oxyhydrogen gas supply unit; The hydrogen and oxygen supply unit comprises an electrolytic water device (11), an oxygen buffer tank (12) and a hydrogen buffer tank (14) which are respectively connected with the electrolytic water device (11), wherein the outlet of the hydrogen buffer tank (14) is respectively connected with the biological crude oil production unit and the hydrofining reactor (19) through a reaction section compressor (15); The power supply unit supplies power to the water electrolysis device (11); The hydrofining and fractionating unit comprises a hydrofining reactor (19) and a product fractionating tower (21) connected with a refined oil outlet of the hydrofining reactor (19); the waste heat utilization unit comprises a waste heat boiler (5) and a steam turbine (22) connected with a high-pressure steam outlet of the waste heat boiler (5), and the steam turbine (22) is connected with a generator; Medium-pressure steam discharged by the steam turbine (22) is respectively introduced into the heat pump rectifying system (20) and the lithium bromide refrigerator (23), the lithium bromide refrigerator (23) provides cold energy for the PSA hydrogen purification unit (13) and the Fischer-Tropsch product separator (8), and the heat pump rectifying system (20) supplies heat for the product fractionating tower (21) in a high-efficiency manner.

Description

Method and system for preparing green aviation kerosene by cooperation of biogas and lignin Technical Field The invention belongs to the technical field of biomass energy and green chemical industry, and particularly relates to a method and a system for preparing green aviation kerosene by cooperation of biogas and lignin. Background The need to deal with climate change and drive aviation decarburization has become a global consensus. Sustainable aviation fuels (Sustainable Aviation Fuel, SAF) are considered the most effective way to achieve aviation emissions reduction in the mid-to-short term because they can directly replace traditional petroleum-based aviation fuels. At present, the production raw materials and technical routes of SAF show diversified development, mainly comprising esters and fatty acid Hydrogenation (HEFA), alcohol injection fuel (ATJ), fischer-Tropsch synthesis (FT-SPK) and the like. The Fischer-Tropsch synthesis route takes synthesis gas generated by biomass gasification as a raw material, and the synthesis gas is used for catalyzing and synthesizing straight-chain alkane, and the product has the characteristics of high cetane number and extremely low sulfur content, and is approved to be blended with conventional aviation kerosene for use in a proportion of not more than 50 percent. However, FT-SPK consists mainly of linear and isoparaffins, with little aromatics. Aviation fuel standards are tightly defined for aromatic content (typically 8% -25%) as they are critical to the swelling properties of engine seals. Insufficient aromatic hydrocarbon content may cause potential safety hazards such as fuel leakage, which becomes a technical bottleneck limiting the use of FT-SPK as a full-scale (100%) SAF. On the other hand, lignin is the most abundant renewable aromatic polymer in nature and is an ideal source of aromatic components of biological aviation kerosene. Lignin can be converted into biocrude rich in aromatic compounds such as alkylbenzenes, alkylnaphthalenes, etc. by catalytic depolymerization and Hydrodeoxygenation (HDO) techniques. However, this process generally requires the consumption of a large amount of expensive hydrogen gas, and the reaction conditions are severe, and the individual treatment economy is poor. Biogas (the main components are CH 4 and CO 2) is a product of anaerobic fermentation of organic waste, and the traditional utilization mode (power generation and purification into biological natural gas) has limited economic added value. The methane is a more valuable path for preparing the synthetic gas through reforming, but the traditional steam reforming has extremely high energy consumption, the dry reforming can utilize CO 2 but has the problems of serious carbon deposition, quick catalyst deactivation and the like, and the autothermal reforming can realize energy coupling, but has poor combustion stability and poor adaptability to raw material fluctuation. In the prior art, schemes combining biomass gasification Fischer-Tropsch synthesis with oil and fat hydroprocessing have been proposed to reconcile product components, but the sources of raw materials are limited. Research and exploration have also been conducted to separate methane reforming from biomass conversion, but the following significant problems exist: (1) The system is complex, the energy consumption is high, the investment of two independent production lines is large, hydrogen and energy are required to be externally supplied, and the overall energy efficiency is low; (2) The carbon emission reduction potential is not fully exerted, the internal circulation of materials and energy is not realized, and the carbon emission in the process is higher; (3) The economy is poor, and the high hydrogen cost and the external energy consumption lead to the lack of competitiveness of the production cost; (4) The product components and flexibility are poor, and the hydrocarbon composition, particularly the aromatic hydrocarbon content of the final fuel is difficult to precisely control. Therefore, an innovative integrated process is urgently needed in the field, two cheap and abundant biomass wastes of methane and lignin can be subjected to efficient cooperative conversion, the defects of the prior art are overcome through process strengthening and energy coupling, and full-proportion green aviation kerosene with qualified components is economically and efficiently produced. The ideal solution should be capable of realizing self-balancing of heat in the reaction process, solving the carbon deposition problem in the reforming process, reducing hydrogen consumption by utilizing byproduct waste in the process, and finally directly producing qualified aviation kerosene products through component blending at the molecular level. Disclosure of Invention The invention aims to solve the technical problems of low raw material utilization rate, insufficient aromatic hydrocarbon content, high energy consumption, large