SOEC-based biomass pyrolysis steam integrated coupling online upgrading system and process

Abstract

The invention relates to an SOEC-based biomass pyrolysis steam integrated coupling online upgrading system and process, the system comprises a steam generator, a solid oxide electrolytic tank SOEC, an electrochemical workstation and a rapid pyrolysis furnace, the SOEC is of a sandwich structure and sequentially comprises an air electrode, an electrolyte and a fuel electrode from top to bottom, the SOEC is fixed in the heating furnace through a hollow reaction pipe, an air inlet pipe a is arranged above an air electrode of the SOEC and is communicated with the steam generator, and a feeding pipe b is arranged below a fuel electrode of the SOEC and is communicated with the rapid pyrolyzing furnace and an air pump; the feeding pipe b is positioned in the hollow reaction pipe to form a double-layer reaction channel. Compared with the prior art, the oxygen content of the biomass pyrolytic oil can be remarkably reduced, and the heat value and stability of the bio-oil can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass energy utilization, and relates to an integrated coupled upgrading process of biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC (solid oxide electrolysis cell). Background Art

[0002] Biomass pyrolysis technology has the advantages of full component utilization, strong raw material adaptability and high conversion efficiency. It can efficiently transform biomass into liquid bio-oil with high energy density and easy storage and transportation in a continuous and industrialized production mode. Further quality improvement and modification can produce aviation fuel and high-value chemicals. Pyrolysis technology has a wide range of uses and flexible scale. Distributed biomass pyrolysis technology conforms to the characteristics of my country's dispersed biomass resources. It is one of the effective ways to truly realize the development and utilization of biomass "according to local conditions", which will help my country achieve the 3060 carbon peak and carbon neutrality goals as soon as possible.

[0003] The crude bio-oil obtained by pyrolysis of biomass has low quality, complex composition, high oxygen content, low calorific value, high acid value, high viscosity and poor stability, which makes the bio-oil difficult to use and handle. This is mainly because the crude bio-oil contains a large number of oxygen-containing groups. The high oxygen content makes the low calorific value of crude bio-oil only 13-18 MJ / kg, which is much lower than the 46 MJ / kg of motor gasoline; the presence of acidic oxygen-containing groups causes the pH of crude bio-oil to be around 2.5, which is corrosive; the secondary reaction of highly active oxygen-containing functional groups causes crude bio-oil to be prone to aging and polymerization, making it difficult to store and transport for a long time. Therefore, it is necessary to refine and improve the quality of crude bio-oil so that it can be stably stored and transported.

[0004] There are many methods for upgrading crude bio-oil at present, the most important methods are catalytic hydrogenation, catalytic cracking, catalytic esterification, emulsification, etc. Among them, catalytic hydrogenation is one of the most feasible methods for upgrading crude bio-oil. Catalytic hydrogenation is to remove oxygen in the crude bio-oil in the form of H2O under the action of a catalyst at a certain temperature (>350 ℃) and high hydrogen partial pressure (10 MPa-20 MPa), so as to achieve the purpose of quality improvement. However, the reaction conditions of catalytic hydrogenation are relatively harsh (high temperature and high pressure), and an external hydrogen source is required. It can only be carried out through batch reactions in reactors, which reduces safety and economy and is difficult to produce continuously.

[0005] Patent CN118491439A discloses a reaction system for producing hydrogen by aqueous phase reforming coupled with catalytic hydrothermal liquefaction to produce bio-oil, including a catalytic hydrothermal liquefaction unit, a gas high-pressure separation and reuse unit, a product separation unit, and an aqueous phase reforming hydrogen production unit. The liquefied wastewater obtained by hydrothermal liquefaction separation is used as water for biomass slurry preparation and raw material for aqueous phase reforming reaction. The hydrogen obtained by high-pressure separation of the gas-liquid separator after the hydrothermal liquefaction reaction is directly compressed and pressurized by a compressor and then sent to the hydrothermal liquefaction reactor for reuse. The catalyst loaded in the hydrothermal liquefaction reactor has the functions of catalytic aqueous phase reforming of liquefied wastewater to produce hydrogen and hydrothermal liquefaction of bio-oil to hydrogenate and improve the quality of bio-oil. In the process of hydrothermal liquefaction reaction, hydrogen can be produced in situ for in-situ hydrogenation and quality improvement of hydrothermal liquefaction of bio-oil to improve the quality of bio-oil. However, the liquefied wastewater needs to be recycled multiple times in the entire preparation process. In addition, the crude bio-oil must first be miscible with the catalyst to facilitate processing, but then the upgraded bio-oil must be effectively separated from the solvent. This step not only increases the overall upgrading cost, but also limits the scope of treatment to the aqueous phase of the crude bio-oil.

[0006] Patent CN202311469870.9 A method for preparing biodiesel by hydrogenation and deoxygenation of bio-oil, comprising the steps of: (a) mixing the pre-filtered raw bio-oil with hydrogen, and adding it to a first fixed bed reactor at a temperature of 150°C-300°C for hydrogenation saturation and hydrogenation demetallization reaction. (b) mixing the product of step (a) with a sulfiding agent and hydrogen, and carrying out a hydrogenation and deoxygenation reaction under the action of a hydrogenation and deoxygenation catalyst. Through the method of the present invention, the hydrogenation process is divided into two stages, and the effects of hydrogenation and deoxygenation of bio-oil are increased by the hierarchical configuration of the catalyst and the hierarchical control of the reaction temperature, thereby improving the quality of biodiesel. However, this method belongs to a two-stage hydrogenation process, which is difficult to produce continuously and has limited promotion.

[0007] Electrochemical hydrogenation is an economical and environmentally friendly method for converting cheap raw materials into multifunctional chemicals. However, it is completed in a liquid phase low-temperature system and has the following defects: 1) The crude bio-oil to be upgraded needs to be miscible with the electrolyte, and the upgraded bio-oil needs to be separated from the electrolyte, which increases the upgrading cost and can only process the aqueous phase component of the crude bio-oil; 2) This method generates in-situ H through electrical energy at room temperature and pressure, which has the problems of large mass transfer resistance and low reaction rate. Therefore, the reaction time of liquid phase electrocatalytic hydrogenation is relatively long, and it generally takes more than 4 hours to reach the target conversion rate; 3) Limited by the above two points, liquid phase electrocatalytic hydrogenation needs to be carried out in batches, which is difficult to produce continuously and has poor matching with the front-end biomass pyrolysis oil production process.

[0008] CN202211084348.4 discloses a medium-temperature electrochemical upgrading process for biomass pyrolysis steam, the technical solution of which is to continuously feed the biomass raw material into the biomass fast pyrolysis furnace through a screw feeder for fast pyrolysis; the pyrolysis steam is directly passed into the cathode channel of the proton ceramic exchange membrane electrolyzer without cooling, and the water vapor generated by the steam generator is passed into the anode of the proton ceramic exchange membrane electrolyzer; the proton ceramic exchange membrane electrolyzer is externally connected to a DC power supply for electrochemical reaction, thereby completing the upgrading of bio-oil in the pyrolysis steam. This technology directly electrochemically hydrogenates and upgrades the biomass pyrolysis steam without condensation, significantly reducing the number of unsaturated bonds in the biomass pyrolysis oil, reducing the acidity and viscosity of the biomass pyrolysis oil, improving its calorific value and stability, and improving the quality of the biomass pyrolysis oil, but the composition of the biomass pyrolysis steam is complex, including organic matter such as tar, phenols, and acids, and the proton exchange membrane has a high sensitivity to impurities in the steam. These impurities may be deposited on the surface of the catalyst or proton exchange membrane in the electrolytic cell, causing membrane poisoning, clogging or catalyst deactivation, and reducing the efficiency of the electrochemical reaction. This results in the need for additional gas purification steps, which increases the complexity and cost of the process. In addition, proton exchange membrane electrolyzers are equipped with expensive precious metal catalysts. These materials are expensive and may need to be replaced frequently once they become deactivated or their performance degrades, especially in large-scale industrial applications. This will significantly increase the manufacturing and maintenance costs of the equipment. The normal operation of the proton exchange membrane depends on proper humidity, which should not be too dry or too wet. In the process of electrochemical quality improvement, water vapor is both a reactant and a reaction product. How to maintain the water management balance inside the electrolytic cell is a challenge.

[0009] In addition, due to the hydrogen production performance limitations of the electrolytic cell type used in CN202211084348.4, if a continuous hydrogenation reaction is to be achieved, a symmetrical dual electrolytic cell structure must be designed. This design makes the pyrolysis gas enter the reactor in a parallel structure with the reaction surface, resulting in a large amount of pyrolysis gas being unable to effectively contact the reaction surface. At the same time, due to the time relaxation effect when the reaction interface on the same side contacts the pyrolysis gas, this further exacerbates the concentration polarization (between the upper and lower reaction surfaces) and activation polarization (the difference between the left reaction surface and the right reaction surface in the electrolytic cell on the same side). All these factors greatly reduce the hydrogen production performance of the electrolytic cell and have an adverse effect on the reaction efficiency and product selectivity. In addition, the dual electrolytic cell structure cannot effectively collect the product. Summary of the invention

[0010] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a biomass pyrolysis steam electrochemical hydrogenation saturated deoxygenation integrated coupling quality improvement system and process based on SOEC, which can continuously hydrodeoxygenate crude bio-oil, have a high deoxygenation rate and high selectivity for aromatic liquid phase products.

[0011] The object of the present invention can be achieved by the following technical scheme: a biomass pyrolysis steam electrochemical hydrogenation saturation deoxygenation integrated coupling upgrading system based on SOEC, the system includes a steam generator, SOEC, an electrochemical workstation, and a fast pyrolysis furnace, the SOEC is a sandwich structure, which is an air electrode-electrolyte-fuel electrode from top to bottom, characterized in that the SOEC is fixed in the heating furnace through a hollow reaction tube, an air inlet pipe a is provided above the air electrode of the SOEC to connect to the steam generator, and a feed pipe b is provided below the fuel electrode of the SOEC to connect to the fast pyrolysis furnace and the air pump; the feed pipe b is located inside the hollow reaction tube to form a double-layer reaction channel; The water vapor generated by the steam generator is electrolyzed on the air electrode surface of the SOEC to generate H, which then enters the fuel electrode side and reacts with the gas from the fast pyrolysis furnace after pyrolysis of biomass to undergo gas-solid phase electrochemical hydrogenation and upgrading reaction. The resulting reaction product flow moves in the same chamber of the double-layer reaction channel in a countercurrent manner, thereby forming the conditions of a continuous stirred tank reactor and realizing online deep hydrogenation and upgrading of bio-oil.

[0012] Furthermore, the steam generator is connected to the air electrode of the SOEC through an air inlet pipe a wrapped by a heating pipe a; the lower end of the air inlet pipe a is 1.0-1.5 cm away from the air electrode of the SOEC.

[0013] Furthermore, the sandwich structure SOEC is a conventional commercial product or is prepared using existing technology. Preferably, the air is La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; The electrolyte is BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; The fuel is Nio-BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; The air electrode and the fuel electrode are respectively connected to an electrochemical workstation, and the electrochemical workstation applies voltage to the SOEC to generate H.

[0014] Furthermore, the fast pyrolysis furnace directly enters the fuel electrode of SOEC through a feed pipe b wrapped by a heating pipe b; the upper end of the feed pipe b is 0.5-1.0 cm away from the fuel electrode of SOEC; the feed pipe b is located inside the hollow reaction tube, the pipe diameter ratio is 1:2.5, and the length of the preheating part of the feed pipe b in the heating furnace is 35 cm; The fast pyrolysis furnace is connected in parallel with an air pump, through which air is continuously pumped into the feed pipe b, driving the pyrolysis gas to the fuel pole of the SOEC.

[0015] Furthermore, the hydrodeoxygenation product is output to the cooling system through a discharge pipe wrapped by the heating pipe c, and the gas phase product is collected by an air bag.

[0016] The present invention also provides a biomass pyrolysis steam electrochemical hydrogenation saturation deoxygenation integrated coupling quality improvement process based on SOEC using the system, comprising the following steps: S1: The steam generated by the steam generator is introduced into the air electrode of the SOEC at a flow rate of 80-90 mL / min and a temperature of 200-250 °C; S2: The heating furnace heats the SOEC to 600-700 °C at a heating rate of 5-8 °C / min; S3: The electrochemical workstation applies a constant voltage to the SOEC, and the voltage is maintained at 1.3-1.4 V, so that the SOEC starts the electrolysis mode, and a large amount of H is produced from the fuel electrode at the lower end of the SOEC; S4: After the biomass feedstock is pyrolyzed in the fast pyrolysis furnace, it directly enters the fuel electrode of the SOEC through the feed pipe b; S5: At the same time, the air flow rate of the air pump pumped into the feed pipe b is controlled to be 50-60 mL / min, driving the pyrolysis gas to the fuel electrode of the SOEC; S6: The feed stream input through the feed pipe b flows perpendicular to the fuel electrode area, and the pyrolysis gas undergoes a gas-solid phase electrochemical hydrogenation upgrading reaction at the fuel electrode of the SOEC, and the resulting reaction product stream moves in a countercurrent manner in the same chamber, thereby forming a continuous stirred tank reactor condition; S7: The reaction product is transported from the discharge pipe to the cooling system to obtain a condensed liquid product; S8: Non-condensable gases are collected by air bags.

[0017] Further, the water content of the water vapor generated by the steam generator in step S1 is 3%-10%; The flow rate of water vapor is controlled by a mass flow meter, and the temperature of water vapor is controlled by heating the air inlet pipe a through the heating pipe a.

[0018] Further, the pyrolysis conditions of the fast pyrolysis furnace in step S4 are: heating to 500-600°C at a heating rate greater than 10000°C / s and staying for 1s to complete the fast pyrolysis; Biomass raw materials include wood processing residues, forestry logging residues or crop straw agricultural residues.

[0019] Furthermore, in step S4, the temperature of the heating pipe b wrapped outside the feed pipe b is 300-350° C. to prevent condensation, and the fast pyrolysis furnace needs to be purged with nitrogen at a rate of 0.2 L / h for 0.5 h at room temperature before the reaction.

[0020] Furthermore, the discharge pipe in step S7 is heated by a heating pipe c, and the heating temperature is 120-150°C; The cooling system temperature is controlled at minus 5-1 ℃.

[0021] The Solid Oxide Electrolysis Cell (SOEC) is a sandwich structure, which consists of an air electrode, an electrolyte, and a fuel electrode from top to bottom. SOEC can work normally in the range of 500 ℃-850 ℃, and has great compatibility with the biomass pyrolysis process. The present invention proposes an online electrochemical upgrading process of biomass pyrolysis steam based on SOEC by utilizing the characteristics of SOEC's fast reaction rate and the matching working range with biomass pyrolysis. The pyrolysis steam does not need to be condensed and directly enters the SOEC for online electrochemical hydrogenation and upgrading. Water vapor decomposes into oxygen and hydrogen protons at the air electrode, and the hydrogen protons reach the fuel electrode through the electrolyte, and react with the biomass pyrolysis steam at the three-phase interface of the fuel electrode in a gas-solid phase, thereby converting the unsaturated functional groups in the pyrolysis steam into saturated functional groups, and improving the quality of bio-oil online.

[0022] Based on the SOEC hydrogen production technology, the present invention proposes a new process for online quality improvement of biomass pyrolysis steam electrochemical hydrogenation saturation deoxygenation integrated coupling. The present invention can achieve online electrochemical hydrogenation saturation-deoxygenation integrated coupling quality improvement of biomass pyrolysis steam through the steps of rapid biomass pyrolysis, SOEC voltage control, air intake and feed flow rate regulation, interface relationship design and gas-solid electrochemical reaction. Specifically: 1. Voltage is a key parameter for controlling electrochemical reactions, which directly affects the free energy change of the reaction ( ). Voltage control requires the following basic thermodynamic and kinetic relationships to be satisfied: , ΔG is the Gibbs free energy of the reaction, n is the number of electron transfers, F is the Faraday constant, and E is the cell voltage. When the voltage is too low, the reaction rate may not be sufficient to drive the hydrogenation and deoxygenation reactions; when the voltage is too high, it may induce undesirable side reactions (electrode degradation). Therefore, the choice of voltage must find a balance between effective hydrogenation reactions and minimization of side reactions. 2. The flow rate control of the inlet gas and feed will affect the residence time in the reactor ( ), thus affecting the sufficiency of gas-solid phase reaction. The relationship between residence time and flow rate usually follows the following formula: , V is the effective volume of the reactor, Q is the volume flow rate of the inlet gas / feed, a shorter residence time may lead to incomplete reaction, while a longer residence time may lead to the formation of by-products. The inlet gas and feed flow rates need to be optimized according to the size of the reactor, the reaction rate and the target yield of the reaction product. The interface design, especially the contact area and structure of the electrode and the electrolyte, has an important influence on the effectiveness of the reaction. The reaction rate is usually related to the effective surface area A of the electrode. eff The rate of gas-solid electrochemical reactions is also limited by mass transfer processes, especially the diffusion of reactants and products between the electrodes and the reactant gas phase. The mass transfer rate is often described by the Sherwood number Sh and the Peclet number Pe: , , is the mass transfer coefficient, L is the characteristic length, D is the diffusion coefficient, U It is the flow rate, therefore, the gas flow rate and reactor design need to be balanced to ensure that the mass transfer rate and reaction rate match. Compared with the traditional thermal catalytic hydrogenation quality improvement method, the biomass pyrolysis vapor in the present invention does not need to be condensed into crude bio-oil, and can be upgraded online, avoiding energy loss; at the same time, no external hydrogen source is required, and redundant wind, solar and hydropower can be consumed, greatly reducing the cost of quality improvement. The successful implementation of the present invention is expected to break through the bottleneck problem of the current complex process and high cost of preparing high-value fuels by biomass pyrolysis, and contribute to the industrial promotion of high-value utilization technology of biomass pyrolysis.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) In the present invention, SOEC electrolysis hydrogen production is coupled with biomass pyrolysis hydrogenation technology, wherein the adopted SOEC has higher energy efficiency. Since SOEC operates at high temperature (usually between 500°C and 850°C), external heat energy can directly participate in the electrolysis reaction, thereby reducing the required electrical energy input. Under high temperature conditions, part of the reaction energy is provided by heat, so the voltage required for the electrolysis reaction is lower and the electrical energy utilization rate is higher, which makes the hydrogenation and upgrading system of the present invention more energy-efficient. SOEC can use waste heat from industrial processes or thermal energy from renewable energy sources (such as solar energy) to heat the electrolysis cell. This "thermal and electric synergy" approach not only reduces the external electrical energy demand, but also makes the entire system more sustainable, especially when integrated with energy systems such as high-temperature industrial processes or solar thermal power plants. In addition, the reaction rate in low-temperature electrolysis (such as PEMEC and alkaline electrolysis cells) is limited by temperature, and the hydrogen production efficiency is low. The working characteristics of SOEC make this system unnecessary for external hydrogen source, and the high temperature operation condition helps to increase hydrogen production. Through this system, redundant wind energy, solar energy and hydropower can be directly used to produce hydrogen, so this system is very suitable for large-scale hydrogenation and upgrading industry.

[0024] (2) The new process of the present invention can react without catalysts through system design and simplified process flow, avoiding the problems of short catalyst life, easy coking and deactivation, catalyst regeneration or replacement process, low yield of upgraded bio-oil and low H / C ratio. This is different from the expensive metal catalysts required for traditional hydrocracking and is sensitive to operating conditions. It greatly improves the economic feasibility of high-value utilization of biomass pyrolysis. In addition, the system can be widely adapted to a variety of biomass raw materials, improve the universality and application scope of the process, and help promote the industrial promotion and market application of biomass pyrolysis technology.

[0025] (3) The present invention couples the SOEC electrolysis hydrogen production with the biomass pyrolysis hydrogenation technology. The design of an air pump driving the pyrolysis gas into the hydrogenation reactor allows the biomass pyrolysis steam to be directly upgraded online without condensing into crude bio-oil, successfully avoiding the condensation and reheating steps in the traditional process. This design not only makes the reaction conditions milder and the device structure simpler, but also combines the pyrolysis temperature with the working temperature of SOEC to optimize the feeding process and greatly reduce energy consumption. Through more efficient resource utilization and energy conversion, this system effectively reduces the cost of preparing high-value fuels by pyrolysis of biomass, bringing significant economic advantages for industrial applications.

[0026] (4) The double-layer reaction channel designed in the present invention can realize the movement of the feed flow and the reaction product flow in the same chamber of the reactor in a countercurrent manner, so as to ensure that the concentration gradient between the reactants (such as hydrogen, pyrolysis gas) and the reaction products (such as partially upgraded bio-oil) is always maintained, thereby ensuring mass transfer and reaction rate. Under the countercurrent configuration, the contact between the reactants and the product flow is more precise and controllable, reducing the occurrence of unnecessary side reactions, especially in high temperature environments, avoiding the generation of coke or other undesirable byproducts. This design helps to improve the quality improvement effect of bio-oil and the purity and quality of the final product.

[0027] (5) The countercurrent design is very suitable for continuous reaction processes. Reactants and products can flow continuously without frequent feed and discharge adjustments. The current electrochemical hydrogenation process is usually carried out in a liquid phase low-temperature system. It requires the crude bio-oil to be miscible with the electrolyte and separated from the electrolyte after upgrading. This not only increases the cost, but also limits the treatment of the aqueous phase component of the crude bio-oil. The liquid phase electrocatalytic hydrogenation reaction time is long, usually requiring more than 4 hours to reach the target conversion rate. This type of method needs to be carried out in batches, making it difficult to achieve continuous production, and has poor compatibility with the front-end biomass pyrolysis oil production process. This system can continuously hydrogenate and deoxygenate crude bio-oil, which is particularly important for industrial-scale online deep hydrogenation and upgrading, and can improve the production efficiency and economy of the entire process. The countercurrent operation mode can also reduce the volume required for the reactor, which makes the equipment more compact, saves space and material costs, and thus reduces capital expenditures and maintenance costs in industrial applications.

[0028] (6) The present invention adopts a SOEC electrolytic cell and a single electrolytic cell structure. This design can better control the gas flow distribution, so that the reactor forms reaction conditions similar to those of a continuous stirred tank, avoiding the problems of uneven gas flow and insufficient reaction that may occur in the dual electrolytic cell, ensuring that all pyrolysis gases are in full contact with the reaction interface, thereby optimizing the utilization rate of hydrogen and achieving online deep hydrogenation and quality improvement of bio-oil. Under the premise of ensuring the required hydrogen production, the single electrolytic cell structure effectively avoids the concentration polarization and activation polarization phenomena that may occur in the dual electrolytic cell design. The single electrolytic cell can maintain efficient reaction under a wider range of reaction conditions, adapt to more diverse raw materials and operating conditions, and improve the scalability and applicability of the system.

[0029] In addition, the single electrolytic cell design can optimize the hydrogen reaction site and form a single hydrogen concentration gradient, further realizing the gradient diffusion-gradient reaction process of the pyrolysis gas. Hydrogen concentration gradient control helps in dynamic regulation during the reaction process, making the reaction of hydrogen and pyrolysis gas more balanced and effective. This innovative design significantly improves the selectivity of the reaction, ultimately making the reaction selectivity exceed 97%. Through this technological innovation, the continuous hydrogenation reaction can be kept stable with higher reaction selectivity and efficiency, and the overall performance and stability of the reactor can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the integrated coupled upgrading system of biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC.

[0031] Figure numerals: 1 steam generator; 2 mass flow meter; 3 heating pipe a; 4 air inlet pipe a; 5 SOEC; 6 heating furnace; 7 hollow reaction tube; 8 feed pipe b; 9 electrochemical workstation; 10 heating pipe b; 11 fast pyrolysis furnace; 12 air pump; 13 heating pipe c; 14 discharge pipe; 15 cooling system; 16 air bag.

[0032] Figure 2 This is the GC-MS analysis image of the product of the integrated coupling upgrading of biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC in Example 1. Raw material: pine biomass particles.

[0033] Figure 3 This is the GC-MS analysis image of the product of the integrated coupling upgrading of biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC in Example 2. Raw material: redwood biomass particles.

[0034] Figure 4 This is a gas chromatography-mass spectrometry (Py-GCMS) analysis image of the pine biomass particles after thermal cracking in Comparative Example 1. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] An integrated coupled upgrading system of biomass pyrolysis steam electrochemical hydrogenation saturation deoxygenation based on SOEC, such as Figure 1 As shown: including 1 steam generator; 2 mass flow meter; 3 heating pipe a; 4 air inlet pipe a; 5 SOEC; 6 heating furnace; 7 hollow reaction tube; 8 feed pipe b; 9 electrochemical workstation; 10 heating pipe b; 11 fast pyrolysis furnace; 12 air pump; 13 heating pipe c; 14 discharge pipe; 15 cooling system; 16 air bag.

[0037] Among them, SOEC 5 is a sandwich structure, which is SOEC air electrode-electrolyte-fuel electrode from top to bottom. The air electrode is La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; The electrolyte is BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; The fuel is Nio-BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; The SOEC 5 is fixed in the heating furnace 6 through the hollow reaction tube 7. An air inlet pipe a4 is provided above the air electrode of the SOEC 5 to connect with the steam generator 1. A feed pipe b8 is provided below the fuel electrode of the SOEC 5 to connect with the fast pyrolysis furnace 11. The feed pipe b8 is located inside the hollow reaction tube 7 to form a double-layer reaction channel. The steam generator 1 is connected to the air electrode of the SOEC 5 through the air inlet pipe a4 wrapped by the heating pipe a3; the lower end of the air inlet pipe a4 is 1.0-1.5 cm away from the air electrode of the SOEC 5. The water vapor generated by the steam generator 1 is introduced into the air electrode, The fast pyrolysis furnace 11 directly enters the fuel electrode of SOEC 5 through the feed pipe b8 wrapped by the heating pipe b10; the upper end of the feed pipe b8 is 0.5-1.0 cm away from the fuel electrode of SOEC; the length of the preheating part of the feed pipe b8 in the heating furnace 5 is 35 cm; After the biomass raw material is pyrolyzed in the fast pyrolysis furnace 11, it is separated by a gas-liquid separator, and the gas enters the fuel electrode from bottom to top through the feed pipe b8. The air electrode and the fuel electrode are respectively connected to the electrochemical workstation 9, and the electrochemical workstation 9 applies voltage to the SOEC 5. The water vapor transported by the steam generator 1 is electrolyzed on the surface of the air electrode to generate H, which enters the fuel electrode side after passing through the electrolyte, and undergoes a gas-solid phase electrochemical hydrogenation and upgrading reaction with the gas from the fast pyrolysis furnace 11 after pyrolysis of the biomass. The resulting reaction product flow flows downward from the space between the hollow reaction tube 7 and the feed pipe b8 in the double-layer reaction channel, and moves in a countercurrent manner in the same chamber with the pyrolyzed gas, thereby forming a continuous stirred tank reactor condition, and realizing online deep hydrogenation and upgrading of bio-oil.

[0038] The fast pyrolysis furnace 11 is connected in parallel with an air pump 12, and air is continuously pumped into the feed pipe b8 through the air pump 12, driving the pyrolysis gas to the fuel pole of the SOEC5.

[0039] The bottom of the hollow reaction tube 7 extends out of the heating furnace 6 and is connected to a discharge pipe 14 on its side wall. The hydrodeoxygenation product is output from the hollow reaction tube 7 to the cooling system 15 through the discharge pipe 14 wrapped by the heating pipe c13, and the gas phase product is collected by the air bag 16.

[0040] O2 generated by the electrolysis of water vapor on the surface of the air electrode diffuses into the cavity of the heating furnace 6, increasing the oxygen partial pressure of the air electrode, balancing the partial pressure of the fuel electrode caused by the feed flow, and ensuring the normal progress of the electrochemical reaction.

[0041] The technical solution of the present application will be described in detail below in conjunction with specific embodiments. Unless otherwise specified, the raw materials and equipment used in each embodiment are conventional raw materials and equipment in the art. For example, nano graphite powder can be APS7-11 micron, 99% commercially available product from Alfa. Example 1

[0042] 1. Preparation of Solid Oxide Electrolytic Cell (SOEC) NiO and BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (It can be a commercially available product or prepared by the method reported in existing literature. In this embodiment, reference DOI: 10.1016 / j.jpowsour.2011.08.047 adopts solid phase method) Mix the mixture in a mass ratio of 6:4, and then add 10 wt.% of the total mass of the mixture to obtain a composite fuel electrode powder. Weigh 0.30 g of the composite fuel electrode powder and pour it into a tableting mold with a diameter of 12 mm to obtain a composite fuel electrode substrate. Add 0.09 g of BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ The electrolyte powder was sprinkled on the composite fuel electrode substrate, uniaxially pressed for 60 s at a pressure of 100 MPa, and then demolded to obtain a semi-electrolyzer embryo. The electrolyte was sintered and compacted in an air atmosphere at 1300 °C for 6 h to obtain a fuel electrode-supported semi-electrolyzer.

[0043] The electrolyte powder BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ with La0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (It can be a commercially available product or prepared by the method reported in the existing literature. In this embodiment, reference document DOI: 10.3390 / ma17040869 is prepared by sol-gel method) The powder is mixed in a mass ratio of 7:3 to obtain a composite air electrode powder. The obtained composite air electrode powder is mixed with 6wt% ethyl cellulose-pinene alcohol binder in a mass ratio of 1:1.5 to prepare a composite air electrode slurry. The obtained composite air electrode slurry is evenly coated on the electrolyte side of the fuel electrode supporting semi-electrolyzer, and calcined in an air atmosphere at 1000°C for 1 h to obtain a complete SOEC. Use high-temperature ceramic glue to fix the SOEC to the top of the feed tube b7.

[0044] 2. Biomass pyrolysis steam electrochemical hydrogenation saturation deoxygenation integrated coupling quality improvement Biomass raw materials include wood processing residues, forestry logging residues and crop straw agricultural residues. In this embodiment, purchased pine biomass pellets are used as the biomass raw materials of this example. Before upgrading, the raw materials are placed in an oven at 120 ° C for drying, and weighed every 5 hours until the mass of the pine biomass pellets no longer changes. The total drying time is 50 hours.

[0045] S1: Steam generator 1 generates water vapor with a water content of 3%, and the flow rate is controlled by mass flow meter 2 to be 85 mL / min. The heating pipe a3 heats the air inlet pipe a4 at a temperature of 220 °C to prevent condensation, and the water vapor is passed into the air electrode of SOEC 5. The lower end of the air inlet pipe a4 is controlled to be 1.0 cm away from the air electrode of SOEC 5; S2: Heating furnace 6 heats SOEC5 to 700 °C at a heating rate of 8 °C / min; S3: The electrochemical workstation 9 applies a constant voltage to SOEC5, and the voltage is maintained at 1.3 V, so that SOEC5 enters the electrolysis mode, and the fuel electrode at the lower end of SOEC5 produces a large amount of H; S4: After pyrolysis in the fast pyrolysis furnace 11 (heating rate greater than 10000 ℃ / s to 500 ℃ and stay for 1 s to complete fast pyrolysis), the pine biomass particles dried for 50 hours are directly fed into the fuel electrode of SOEC 5 through the feed pipe b8 without cooling. The upper end of the feed pipe b8 is 1.5 cm away from the fuel electrode of SOEC 5. The temperature of the heating pipe b10 is 300 ℃ to prevent condensation. Before the reaction, the pyrolysis furnace needs to be purged with nitrogen at room temperature at a rate of 0.2 L / h for 0.5 h. S5: The air pump 12 continuously pumps air into the feed pipe b8 at a flow rate of 55 mL / min, driving the pyrolysis gas to the fuel electrode of SOEC 5; S6: The feed flow flows in the feed pipe b8 perpendicular to the fuel electrode area, and the upper end of the feed pipe b8 is controlled to be 1.0 cm away from the fuel electrode of SOEC 5. The pyrolysis gas undergoes gas-solid phase electrochemical hydrogenation upgrading reaction at the fuel electrode of SOEC 5, while the reaction product flow moves in a countercurrent manner in the same chamber, thereby forming a continuous stirred tank reactor condition.

[0046] S7: The reaction product is transported from the discharge pipe 14 to the cooling system 15 to obtain a condensed liquid product, and the heating temperature of the heating pipe c12 is 120° C.; S8: The non-condensable gas is collected by the air bag 16. Example 2

[0047] 1. Preparation of Solid Oxide Electrolytic Cell (SOEC) Step (i) is the same as in Example 1 to prepare a solid oxide electrolytic cell.

[0048] 2. Biomass pyrolysis steam electrochemical hydrogenation saturation deoxygenation integrated coupling quality improvement Biomass raw materials include wood processing residues, forestry logging residues and crop straw agricultural residues. In Example 2, purchased redwood biomass particles are used as the biomass raw materials of this example. Before upgrading, the raw materials are placed in an oven at 120 ° C for drying, and weighed every 5 hours until the mass of the redwood biomass particles no longer changes. The total drying time is 50 hours.

[0049] S1: Steam generator 1 generates water vapor with a water content of 3%, and the flow rate is controlled by mass flow meter 2 to be 80 mL / min. Heating pipe a3 heats inlet pipe a4 at a temperature of 250 °C to prevent condensation, and water vapor is passed into the air electrode of SOEC5. The lower end of inlet pipe a4 is controlled to be 1.5 cm away from the air electrode of SOEC5. S2: heating furnace 6 heats SOEC 5 to 650 °C at a heating rate of 5 °C / min; S3: The electrochemical workstation 9 applies a constant voltage to SOEC5, and the voltage is maintained at 1.4 V, so that SOEC5 enters the electrolysis mode, and the fuel electrode at the lower end of SOEC5 produces a large amount of H; S4: After the dried redwood biomass particles are pyrolyzed in the fast pyrolysis furnace 11 (the heating rate is greater than 10000 ℃ / s and the temperature is raised to 600 ℃ and the temperature is kept for 1 second to complete the fast pyrolysis), they are directly fed into the fuel electrode of SOEC 5 through the feed pipe b8 without cooling. The upper end of the feed pipe b8 is 1 cm away from the fuel electrode of SOEC 5. The temperature of the heating pipe b10 is 350 ℃ to prevent condensation. Before the reaction, the pyrolysis furnace needs to be purged with nitrogen at room temperature at a rate of 0.2 L / h for 0.5 h. S5: The air pump 12 continuously pumps air into the feed pipe b8 at a flow rate of 60 mL / min, driving the pyrolysis gas to the fuel electrode of SOEC 5; S6: The feed flow flows in the feed pipe b8 perpendicular to the fuel electrode area, and the upper end of the feed pipe b8 is controlled to be 0.5 cm away from the fuel electrode of SOEC5. The pyrolysis gas undergoes a gas-solid phase electrochemical hydrogenation upgrading reaction at the fuel electrode of SOEC5, while the reaction product flow moves in a countercurrent manner in the same chamber, thereby forming a continuous stirred tank reactor condition.

[0050] S7: The reaction product is transported from the discharge pipe 14 to the cooling system 15 to obtain a condensed liquid product, and the heating temperature of the heating pipe c12 is 150° C.; S8: The non-condensable gas is collected by the air bag 16.

[0051] Comparative Example 1 Pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS) is an analytical method that combines pyrolysis technology with gas chromatography-mass spectrometry. In this comparative example, pine biomass particles were used as raw materials, and the product distribution before hydrogenation was analyzed by pyrolysis-gas chromatography-mass spectrometry. Specific equipment parameters of PY-GC-MS: The pyrolysis mode was set to flash direct pyrolysis mode. Before the experiment, the experimental quartz pyrolysis tube was cleaned with a tube furnace and an ultrasonic cleaner, and quartz wool was inserted. A blank sample was used for a preliminary experiment to ensure that there were no other contaminants in the analysis system. The instrument carrier gas was high-purity nitrogen with a carrier gas flow rate of 50 mL / min. The temperature was increased to 700 ℃ at a heating rate of 10 ℃ / ms and then maintained for 15s. The transfer line temperature was stabilized at 300 ℃, and the pyrolysis products were injected into the GC through a fused silica transfer tube. In order to reduce and avoid the influence of secondary reactions on the weight loss characteristics, the sample volume used was controlled to 1 μL. The chromatographic column used was Restek VMS (inner diameter 30 m×0.25 mm, film thickness 1.4 μm). The chromatographic heating conditions were: maintain at 40 °C for 60 s, then increase the temperature to 240 °C at 8 °C / min and maintain for 24 min. The split ratio was 1:50, the chromatographic interface temperature was 250 °C, and the remaining temperatures were controlled at 200 °C to prevent condensation of pyrolysis products.

[0052] The liquid product obtained in Example 1-2 was analyzed using a gas chromatography mass spectrometer (GC-MS), and the gas product was analyzed using a gas chromatography-flame ionization detector (GC-FID). The GC-MS quantitative method is the internal standard method and the effective carbon number method. Select an appropriate reference substance (internal standard compound, here dichloromethane) to add to the sample to be tested, calculate the ratio of the response value of the test compound and the internal standard compound (called the relative response factor), and quantify it based on the relative response factor and the content of the added internal standard compound, which is called the internal standard method. The specific calculation can be performed by the following formula: ;in and are the contents of the test compound and the internal standard compound, respectively. is the relative response factor, and is the peak area ratio of the test compound and the internal standard compound.

[0053] The relative response value used for GC-FID is mainly related to the effective carbon number of the molecule, so the ratio of the response value of the test compound and the internal standard compound can be calculated by the effective carbon number method. The effective carbon number method means that the relative molar response value (RMR) of the substance is proportional to the number of carbon atoms in the molecule, that is, the amount of the substance of the test compound can be calculated by the following formula: ; like Figure 4 As shown, Py-GCMS represents pyrolysis-gas chromatography-mass spectrometry, which characterizes the product distribution before hydrogenation, and GC spectrum represents gas chromatography spectrum, which characterizes the product distribution after hydrogenation. The GC-MS results show that the rapid pyrolysis products in Comparative Example 1 mainly include furan group derivative compounds and a small amount of olefins and aromatic derivative compounds. Among them, the total content of furan, 2-acetylfuran and 5-methylfuranaldehyde accounts for more than 80% of the overall pyrolysis products, and the pyrolysis products are more complex, with some coking products, and the content of oxygen-containing compounds and aromatic hydrocarbons increased significantly.

[0054] like Figure 2 As shown, the GC spectrum represents the gas chromatography spectrum, which characterizes the distribution of products after hydrogenation. The GC-MS results show that the main liquid products after the integrated coupling upgrading of biomass pyrolysis steam electrochemical hydrogenation saturated deoxygenation based on SOEC are monocyclic aromatic hydrocarbons, containing a small amount of furan derivatives and oxygen-containing compounds. Compared with Comparative Example 1, the electrocatalytic hydrogenation of SOEC in Example 1 has a significant hydrogenation and upgrading effect on the pyrolysis products, and the main products are reduced from 27 to 12. The proportion of oxygen-containing compounds in the product is significantly reduced, and no polymerization products appear. The selectivity of liquid products of monocyclic aromatic hydrocarbons exceeds 80%, and the deoxygenation rate exceeds 90%.

[0055] like Figure 3As shown, the GC spectrum represents the gas chromatography spectrum, which characterizes the distribution of products after hydrogenation. In Example 2, the relative content of furan derivatives has increased, and the types and relative contents of polymerization products have decreased. In addition to a small amount of α-pyrone obtained by planar hydrogen transfer of vinyl ketone [O=C= CH-CH = CH-CHO], the product contains only monocyclic aromatic compounds and no other liquid phase substances. The selectivity of the aromatic liquid phase product in Example 2 exceeds 97%, the proportion of oxygen compounds is significantly reduced, and the deoxygenation rate also exceeds 90%.

[0056] Table 1 Calorific value and stability parameters of comparative examples and examples 1 and 2 after hydrogenation

[0057] The data in Table 1 show that hydrogenation significantly improves the calorific value and stability of bio-oil. The high calorific values ​​of Example 1 and Example 2 are 58.2 MJ / kg and 57.4 MJ / kg, respectively, which are significantly higher than the 17.8 MJ / kg of the comparative example, and the low calorific value is also increased from 13.1 MJ / kg of the comparative example to 41.7 MJ / kg and 40.2 MJ / kg. This shows that the calorific value of bio-oil can be greatly improved by hydrogenation and upgrading, approaching the level of traditional fossil fuels. In addition, the acid value after hydrogenation treatment is reduced from 27.3 mgKOH / g of the comparative example to 10.1-11.3 mgKOH / g, indicating that the acidic components are significantly reduced and the chemical stability is improved. In terms of viscosity, the viscosity of Example 1 and Example 2 is 4.5-4.6 cP, which is significantly lower than the 15.1 cP of the comparative example, indicating that the fluidity of the bio-oil is better and the handling and use performance are improved. Most notably, the oxygen content was reduced from 47.2 wt.% in the control to 3.6-4.2 wt.% after hydrogenation, which greatly improved the calorific value and combustion performance. Overall, hydrogenation effectively improved the quality of bio-oil, optimizing its key parameters such as calorific value, acid value, viscosity and oxygen content, showing better fuel properties and industrial application potential.

[0058] In view of the fact that the current electrochemical hydrogenation of bio-oil is limited to the liquid phase low-temperature hydrogenation system, it is difficult to operate continuously, and the hydrogenated bio-oil and electrolyte need to be separated, which has a low compatibility with the front-end biomass pyrolysis process. The present invention utilizes the characteristics of SOEC working range matching biomass pyrolysis, and proposes an online electrochemical upgrading system and process of biomass pyrolysis steam based on SOEC. The system has the characteristics of mild reaction conditions and simple device structure, and can perform effective electrochemical hydrogenation and deoxygenation under medium temperature, normal pressure, low energy and highly controllable reaction and input conditions, avoiding the high temperature, high pressure and complex catalyst requirements commonly seen in traditional processes. This not only simplifies the equipment structure and reduces the operating cost, but also improves the safety and energy efficiency of the process. The mildness is reflected in that compared with the traditional hydrogenation process, there is no need to react under high pressure (>100 MPa) to increase the solubility and reaction rate of hydrogen in bio-oil. The upgrading process proposed in the present invention relies on electrochemical reaction for hydrogenation, does not require the introduction of high-pressure hydrogen, and can be operated under normal pressure or low pressure conditions. This not only reduces the demand for complex pressurization equipment, but also improves the safety of operation. In addition, the mildness of the reaction conditions is also reflected in the use of SOEC for hydrogenation and quality improvement, and the reaction voltage can be precisely controlled by an external electrochemical workstation. This high degree of controllability allows the reaction to be hydrogenated and deoxygenated under controllable energy requirements, avoiding the problem of overreaction, thereby reducing unnecessary side reactions, especially avoiding the occurrence of side reactions such as coking or cracking. Since the SOEC electrochemical reaction mainly relies on the action of solid electrolytes and electrode materials, no complex chemical catalysts are required, nor is there a need for catalyst regeneration or replacement processes. This is different from the expensive and operating condition-sensitive metal catalysts required for traditional hydrocracking, which greatly simplifies the operating conditions and structural devices of the system.

[0059] The above shows and describes the basic process, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is determined by the attached claims and their equivalents.

Claims

1. A biomass pyrolysis steam integrated coupling online upgrading system based on SOEC, the system comprising a steam generator (1), SOEC (5), an electrochemical workstation (9), and a fast pyrolysis furnace (11), wherein the SOEC (5) is a sandwich structure, which is composed of an air electrode, an electrolyte, and a fuel electrode from top to bottom, and is characterized in that: The SOEC (5) is fixed in the heating furnace (6) via a hollow reaction tube (7); an air inlet pipe a (4) is provided above the air electrode of the SOEC (5) to connect with the steam generator (1); a feed pipe b (8) is provided below the fuel electrode of the SOEC (5) to connect with the fast pyrolysis furnace (11) and the air pump (12); the feed pipe b (8) is located inside the hollow reaction tube (7) to form a double-layer reaction channel; The water vapor generated by the steam generator (1) is electrolyzed on the air electrode surface of the SOEC (5) to generate H, and enters the fuel electrode side to react with the gas from the fast pyrolysis furnace (11) after pyrolysis of biomass to produce gas-solid phase electrochemical hydrogenation and upgrading reaction. The resulting reaction product flow moves in the same chamber of the double-layer reaction channel in a countercurrent manner, thereby forming a continuous stirred tank reactor condition, and realizing online deep hydrogenation and upgrading of bio-oil; The air electrode and the fuel electrode are respectively connected to an electrochemical workstation (9), and the voltage applied by the electrochemical workstation (9) to the SOEC (5) satisfies the following thermodynamic and kinetic relationships: , ΔG is the Gibbs free energy of the reaction, n is the number of electrons transferred, F is the Faraday constant, and E is the cell voltage; The relationship between the residence time and flow rate of the air inlet pipe a (4) and the feed pipe b (8) entering the hollow reaction tube (7) follows the following formula: , V is the effective volume of the reactor and Q is the volume flow rate of the inlet gas / feed.

2. According to claim 1, a biomass pyrolysis steam integrated coupling online upgrading system based on SOEC is characterized in that: The steam generator (1) is connected to the air electrode of the SOEC (5) through an air inlet pipe a (4) wrapped by a heating pipe a (3); the lower end of the air inlet pipe a (4) is 1.0-1.5 cm away from the air electrode of the SOEC (5).

3. The SOEC-based biomass pyrolysis steam integrated coupling online upgrading system according to claim 1 is characterized in that: The fast pyrolysis furnace (11) directly enters the fuel electrode of the SOEC through a feed pipe b (8) wrapped by a heating pipe b (10); the upper end of the feed pipe b (8) is 0.5-1.0 cm away from the fuel electrode of the SOEC; the length of the preheating section of the feed pipe b (8) in the heating furnace (6) is 30-40 cm; The fast pyrolysis furnace (11) is connected in parallel with an air pump (12), and air is continuously pumped into the feed pipe b (8) through the air pump (12), thereby driving the pyrolysis gas to the fuel electrode of the SOEC.

4. The SOEC-based biomass pyrolysis steam integrated coupling online upgrading system according to claim 1 is characterized in that: The feed pipe b (8) is located inside the hollow reaction tube (7), and the pipe diameter ratio of the feed pipe b (8) to the hollow reaction tube (7) is 1:(2-3), so as to ensure that the reaction product flow moves in the same chamber of the double-layer reaction channel in a countercurrent manner.

5. The SOEC-based biomass pyrolysis steam integrated coupling online upgrading system according to claim 1, characterized in that: The hydrodeoxygenation product is output to the cooling system (15) through the discharge pipe (14) wrapped by the heating pipe c (13), and the gas phase product is collected by the gas bag (16).

6. A biomass pyrolysis steam integrated coupled online upgrading process based on SOEC using the system as described in any one of claims 1 to 5, characterized in that: The following steps are involved: S1: The steam generated by the steam generator (1) is introduced into the air electrode of the SOEC (5) at a flow rate of 80-90 mL / min and a temperature of 200-250 °C; S2: The heating furnace (6) heats the SOEC (5) to 600-700 °C at a heating rate of 5-8 °C / min; S3: The electrochemical workstation (9) applies a constant voltage to the SOEC (5), and the voltage is maintained at 1.3-1.4 V, so that the SOEC (5) starts the electrolysis mode, and a large amount of H is produced from the fuel electrode at the lower end of the SOEC (5); S4: After the biomass feedstock is pyrolyzed in the fast pyrolysis furnace (11), it directly enters the fuel electrode of the SOEC through the feed pipe b (8); S5: At the same time, the air pump (12) is controlled to pump air into the feed pipe b (8) at a flow rate of 50-60 mL / min, driving the pyrolysis gas to the fuel electrode of the SOEC; S6: The feed stream input through the feed pipe b (8) flows perpendicularly to the fuel electrode area, and the pyrolysis gas undergoes a gas-solid phase electrochemical hydrogenation and upgrading reaction at the fuel electrode of the SOEC, and the resulting reaction product stream moves in a countercurrent manner in the same chamber, thereby forming a continuous stirred tank reactor condition; S7: The reaction product is transported from the discharge pipe (14) to the cooling system (15) to obtain a condensed liquid product; S8: The non-condensable gas is collected by the gas bag (16).

7. The SOEC-based biomass pyrolysis steam integrated coupling online upgrading process according to claim 6 is characterized in that: Step S1: the water content of the water vapor generated by the steam generator (1) is 3%-10%; The flow rate of water vapor is controlled by a mass flow meter (2), and the temperature of water vapor is controlled by heating an air inlet pipe a (4) through a heating pipe a (3).

8. The SOEC-based biomass pyrolysis steam integrated coupling online upgrading process according to claim 6 is characterized in that: In step S4, the pyrolysis conditions of the fast pyrolysis furnace (11) are: heating at a rate greater than 10000°C / s to 500-600°C and staying there for 1s to complete the fast pyrolysis; Biomass raw materials include wood processing residues, forestry logging residues or crop straw agricultural residues; In step S4, the temperature of the heating pipe b (10) wrapped outside the feed pipe b (8) is 300-350°C to prevent condensation. Before the reaction, the fast pyrolysis furnace (11) needs to be purged with nitrogen at a rate of 0.2 L / h for 0.5 h at room temperature.

9. The SOEC-based biomass pyrolysis steam integrated coupling online upgrading process according to claim 6, characterized in that: The discharge pipe (14) in step S7 is heated by the heating pipe c (13) at a heating temperature of 120-150°C; The temperature of the cooling system (15) is controlled at -5-1°C.

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