SOEC-based integrated coupling inline upgrading system and process for biomass pyrolysis vapor

Abstract

The present invention relates to an SOEC-based integrated coupling inline upgrading system and process for biomass pyrolysis vapor. The system comprises a steam generator (1), a solid oxide electrolytic cell (SOEC) (5), an electrochemical workstation (9) and a fast pyrolysis furnace (11), wherein the SOEC (5) is of a sandwich structure consisting of an air electrode, an electrolyte and a fuel electrode arranged in sequence from top to bottom; the SOEC (5) is fixed in a heating furnace (6) by means of a hollow reaction tube (7); a steam intake tube a(4) is provided above the air electrode of the SOEC (5) and is in communication with the steam generator (1), and a feed tube b(8) is provided below the fuel electrode of the SOEC (5) and is in communication with the fast pyrolysis furnace (11) and an air pump (12); and the feed tube b(8) is located inside the hollow reaction tube (7), forming a double-layer reaction channel. Compared with the prior art, the present invention can significantly reduce the content of oxygen in biomass pyrolysis oil and improve the calorific value and stability of bio-oil.

Description

SOEC-based biomass pyrolysis steam integrated online quality improvement system and process Technical Field

[0001] This invention belongs to the field of biomass energy utilization technology, and relates to an integrated coupled upgrading process for biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC (solid oxide electrolyzer). Background Technology

[0002] Biomass pyrolysis technology has advantages such as full component utilization, strong raw material adaptability, and high conversion efficiency. It can efficiently convert biomass into easily stored and transportable, high-energy-density liquid bio-oil in a continuous and industrialized production process. Further upgrading and modification of bio-oil can yield aviation fuel and high-value chemicals. Pyrolysis technology has a wide range of applications and is flexible in scale.

[0003] Crude bio-oil obtained from biomass pyrolysis is characterized by low quality, complex composition, high oxygen content, low calorific value, high acid value, high viscosity, and poor stability, making it difficult to apply and process. This is mainly due to the large number of oxygen-containing functional groups in the crude bio-oil. The high oxygen content results in a lower heating value of only 13-18 MJ / kg, far lower than the 46 MJ / kg of gasoline. The presence of acidic oxygen-containing functional groups leads to a pH of around 2.5, making the crude bio-oil corrosive. Furthermore, the secondary reactions of highly reactive oxygen-containing functional groups cause the crude bio-oil to easily age and polymerize, making it difficult to store and transport for extended periods. Therefore, refining and upgrading are essential to improve the quality of crude bio-oil, enabling stable storage and transportation.

[0004] Currently, there are various methods for upgrading crude bio-oil, the most important of which include catalytic hydrogenation, catalytic cracking, catalytic esterification, and emulsification. Among these, catalytic hydrogenation is one of the most feasible methods for upgrading crude bio-oil. Catalytic hydrogenation removes oxygen from crude bio-oil in the form of H2O under certain temperature (>350℃) and high hydrogen partial pressure (10MPa-20MPa) with the help of a catalyst, thereby achieving the purpose of upgrading and modification. However, the reaction conditions for catalytic hydrogenation are relatively harsh (high temperature and high pressure), and an external hydrogen source is required. It can only be carried out in batches in a reactor, which reduces safety and economy, making continuous production difficult.

[0005] Patent CN118491439A discloses a reaction system for producing bio-oil through aqueous reforming coupled with catalytic hydrothermal liquefaction, including a catalytic hydrothermal liquefaction unit, a high-pressure gas separation and recycling unit, a product separation unit, and an aqueous reforming hydrogen production unit. The liquefied wastewater obtained from the hydrothermal liquefaction separation is used as water for biomass slurry preparation and as a raw material for the aqueous reforming reaction. Hydrogen and other gases obtained after high-pressure separation by a gas-liquid separator following the hydrothermal liquefaction reaction are directly compressed and boosted by a compressor before being fed back into the hydrothermal liquefaction reactor for reuse. The catalyst loaded in the hydrothermal liquefaction reactor has the functions of catalytic reforming of liquefied wastewater to produce hydrogen and hydrotreating and upgrading the hydrothermally liquefied bio-oil. During the hydrothermal liquefaction reaction, hydrogen can be produced in situ for use in the in-situ hydrotreating and upgrading of the hydrothermally liquefied bio-oil, thereby improving the quality of the bio-oil. However, the entire preparation process requires multiple recycling of the liquefied wastewater. In addition, the crude bio-oil needs to be miscible with the catalyst to promote the treatment, but then the upgraded bio-oil needs to be effectively separated from the solvent. This step not only increases the overall upgrading cost, but also limits the treatment scope to the aqueous phase of the crude bio-oil.

[0006] Patent CN202311469870.9 discloses a method for preparing biodiesel through hydrodeoxygenation and upgrading of bio-oils, comprising the steps of: (a) mixing pre-filtered raw bio-oils with hydrogen and adding it to a first fixed-bed reactor at a temperature of 150℃-300℃ for hydrosaturation and hydrodemetallization reactions; (b) mixing the product of step (a) with a sulfurizing agent and hydrogen, and carrying out a hydrodeoxygenation and upgrading reaction under the action of a hydrodeoxygenation and upgrading catalyst. This method divides the hydrogenation process into two stages, increasing the effectiveness of hydrosaturation and hydrodeoxygenation of bio-oils and improving the quality of biodiesel through staged catalyst configuration and staged temperature control. However, this method is a two-stage hydrogenation process, which is difficult to implement continuously and has limited applicability.

[0007] Electrochemical hydrogenation is an economical and environmentally friendly method for converting inexpensive raw materials into multifunctional chemicals. However, it is carried out in a liquid-phase low-temperature system, which has the following drawbacks: 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 crude bio-oil; 2) This method generates in-situ hydrogen protons 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, generally requiring more than 4 hours to reach the target conversion rate; 3) Due to the limitations of the above two points, liquid-phase electrocatalytic hydrogenation needs to be carried out in batches, making continuous production difficult and resulting in poor compatibility with upstream biomass pyrolysis oil production processes.

[0008] CN202211084348.4 discloses a medium-temperature electrochemical upgrading process for biomass pyrolysis steam. The key technical point is that biomass raw materials are continuously fed into a rapid biomass pyrolysis furnace via a screw feeder for rapid pyrolysis. The pyrolysis steam is directly introduced into the cathode channel of a proton exchange membrane electrolyzer without cooling, while water vapor generated by a steam generator is introduced into the anode of the proton exchange membrane electrolyzer. The proton exchange membrane electrolyzer is connected to an external DC power supply to carry out an electrochemical reaction, thereby upgrading the bio-oil in the pyrolysis steam. This technology directly electrochemically hydrogenates and upgrades biomass pyrolysis steam without condensation, significantly reducing the number of unsaturated bonds in the biomass pyrolysis oil, reducing its acidity and viscosity, increasing its calorific value and stability, and improving the quality of the biomass pyrolysis oil. However, the composition of biomass pyrolysis steam is complex, containing organic matter such as tar, phenols, and acids, and the proton exchange membrane is highly sensitive to impurities in the steam. These impurities can deposit on the surface of the catalyst or proton exchange membrane in the electrolyzer, leading to membrane poisoning, blockage, or catalyst deactivation, thus reducing electrochemical reaction efficiency. This necessitates additional gas purification steps, increasing process complexity and cost. Furthermore, proton exchange membrane electrolyzers are equipped with expensive precious metal catalysts. These materials are costly, and once deactivation or performance degradation occurs, frequent replacement may be necessary, especially in large-scale industrial applications, significantly increasing the manufacturing and maintenance costs of the equipment. Proton exchange membranes require proper humidity to function correctly; they cannot be too dry or too wet. During electrochemical upgrading, water vapor is both a reactant and a product, making the maintenance of water balance within the electrolyzer a challenge.

[0009] Furthermore, due to the hydrogen production performance limitations of the electrolyzer type used in CN202211084348.4, a symmetrical dual-electrolyzer structure must be designed to achieve continuous hydrogenation. This design results in the pyrolysis gas entering the reactor parallel to the reaction surface, leading to a significant amount of pyrolysis gas failing to effectively contact the reaction surface. Simultaneously, the time relaxation effect at the reaction interface on the same side further exacerbates concentration polarization (between the upper and lower reaction surfaces) and activation polarization (the difference between the left and right reaction surfaces within the same electrolyzer side). All these factors significantly reduce the hydrogen production performance of the electrolyzer and adversely affect reaction efficiency and product selectivity. Moreover, the dual-electrolyzer structure cannot effectively collect the products. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an integrated coupled upgrading system and process for biomass pyrolysis steam electrochemical hydrogenation saturated deoxygenation based on SOEC, which can continuously hydrodeoxygenate crude bio-oil, achieve high deoxygenation rate, and have high selectivity for aromatic liquid phase products.

[0011] The objective of this invention can be achieved through the following technical solution: a biomass pyrolysis steam electrochemical hydrogenation saturated deoxygenation integrated coupled quality improvement system based on SOEC. This system includes a steam generator, a solid oxide electrolysis cell (SOEC), an electrochemical workstation, and a rapid pyrolysis furnace. The SOEC has a sandwich structure, consisting of an air electrode, an electrolyte electrode, and a fuel electrode from top to bottom. The SOEC is fixed inside the heating furnace via a hollow reaction tube. An air inlet pipe a is located above the air electrode of the SOEC, connecting to the steam generator. A feed pipe b is located below the fuel electrode of the SOEC, connecting to the rapid pyrolysis furnace and an air pump. The feed pipe b is located inside the hollow reaction tube, forming a double-layer reaction channel.

[0012] The steam generated by the steam generator is electrolyzed on the air electrode surface of the SOEC to generate hydrogen protons, which then enter the fuel electrode side and undergo a gas-solid phase electrochemical hydrogenation and upgrading reaction with the gas from the pyrolysis of biomass in the fast pyrolysis furnace. The resulting reaction product flows in a countercurrent manner within the same chamber of the double-layer reaction channel, thereby forming continuous stirred tank reactor conditions to achieve online deep hydrogenation and upgrading of bio-oil.

[0013] Furthermore, the steam generator is connected to the air electrode of the SOEC through an air inlet pipe a wrapped with a heating pipe a; the lower end of the air inlet pipe a is 1.0-1.5cm away from the air electrode of the SOEC.

[0014] Furthermore, the sandwich-structured SOEC is a conventional commercially available product or prepared using existing technology; preferably, the air is extremely 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 ;

[0015] The electrolyte is BaZr. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ;

[0016] The fuel mentioned is Nio-BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ;

[0017] The air electrode and fuel electrode are respectively connected to an electrochemical workstation, which applies voltage to the SOEC to generate hydrogen protons.

[0018] Furthermore, the rapid pyrolysis furnace directly enters the fuel electrode of the SOEC through the feed pipe b wrapped by the heating pipe b; the upper end of the feed pipe b is 0.5-1.0 cm away from the fuel electrode of the 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.

[0019] The rapid pyrolysis furnace is connected in parallel with an air pump, which continuously pumps air into the feed pipe b, driving the pyrolysis gas to the fuel electrode of the SOEC.

[0020] Furthermore, the hydrodeoxygenation products are discharged to the cooling system through the discharge pipe wrapped by the heating pipe c, while the gaseous products are collected by the gas bag.

[0021] This invention also provides an integrated coupled upgrading process for biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on the aforementioned system, comprising the following steps:

[0022] S1: Water vapor 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℃.

[0023] S2: The heating furnace heats SOEC to 600-700℃ at a heating rate of 5-8℃ / min;

[0024] S3: The electrochemical workstation applies a constant voltage to the SOEC, maintaining the voltage at 1.3-1.4V, which enables the SOEC to start electrolysis mode, producing a large number of hydrogen protons from the fuel electrode at the lower end of the SOEC.

[0025] S4: After the biomass feedstock is pyrolyzed in the fast pyrolysis furnace, it is directly fed into the fuel electrode of SOEC through feed pipe b;

[0026] S5: At the same time, control the air flow rate of the air pump into the feed pipe b to be 50-60 mL / min, so as to drive the pyrolysis gas to the fuel electrode of SOEC;

[0027] S6: The feed flow input through feed pipe b flows perpendicular to the fuel electrode region. The pyrolysis gas undergoes a gas-solid phase electrochemical hydrogenation and upgrading reaction at the fuel electrode of SOEC. The resulting reaction product flow moves in a countercurrent manner in the same chamber, thus forming the conditions of a continuous stirred tank reactor.

[0028] S7: The reaction products are transported from the discharge pipe to the cooling system to obtain condensed liquid products;

[0029] S8: Non-condensable gases are collected by a gas bag.

[0030] Furthermore, the water content in the steam generated by the steam generator in step S1 is 3%-10%;

[0031] The flow rate of water vapor is controlled by a mass flow meter, and the temperature of water vapor is controlled by heating the inlet pipe a through the heating pipe a.

[0032] Furthermore, the pyrolysis conditions for the rapid pyrolysis furnace in step S4 are: heating to 500-600℃ at a heating rate greater than 10000℃ / s and holding for 1 second to complete rapid pyrolysis;

[0033] Biomass raw materials include wood processing residues, forestry logging residues, or crop straw agricultural residues.

[0034] Furthermore, in step S4, the heating pipe b wrapped around the feed pipe is heated to 300-350℃ to prevent condensation. Before the reaction, the rapid pyrolysis furnace needs to be continuously purged with nitrogen at a rate of 0.2L / h at room temperature for 0.5h.

[0035] Furthermore, the discharge pipe mentioned in step S7 is heated by heating pipe c, and the heating temperature is 120-150℃;

[0036] The cooling system temperature is controlled at -5 to -1℃.

[0037] The Solid Oxide Electrolysis Cell (SOEC) has a sandwich structure, consisting of an air electrode, an electrolyte, and a fuel electrode from top to bottom. SOECs can operate normally within the 500℃-850℃ range and exhibit significant compatibility with biomass pyrolysis processes. This invention utilizes the rapid reaction rate and operating range of SOECs, which are well-matched to biomass pyrolysis, to propose an online electrochemical upgrading process for biomass pyrolysis steam based on SOEC. The pyrolysis steam does not require condensation and directly enters the SOEC for online electrochemical hydrogenation and upgrading. Water vapor decomposes into oxygen and hydrogen protons at the air electrode. The hydrogen protons travel through the electrolyte to the fuel electrode, where they undergo a gas-solid phase reaction with the biomass pyrolysis steam at the three-phase interface. This process transforms unsaturated functional groups in the pyrolysis steam into saturated functional groups, thereby achieving online quality improvement of bio-oil.

[0038] This invention, based on SOEC hydrogen production technology, proposes a novel online quality improvement process integrating electrochemical hydrogenation and saturation deoxygenation of biomass pyrolysis steam. This invention achieves integrated online electrochemical hydrogenation and saturation deoxygenation of biomass pyrolysis steam through steps such as rapid biomass pyrolysis, SOEC voltage control, inlet and feed flow rate regulation, interface design, and gas-solid phase electrochemical reaction. Specifically: 1. Voltage is a key parameter controlling the electrochemical reaction, directly affecting the change in the reaction's free energy (ΔG). Voltage control needs to satisfy the following basic thermodynamic and kinetic relationships: ΔG = -nFE, where 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 electromotive force (voltage). When the voltage is too low, the reaction rate may be insufficient to drive the hydrogenation and deoxygenation reactions; when the voltage is too high, undesirable side reactions (electrode degradation) may occur. Therefore, the choice of voltage must find a balance between efficient hydrogenation and minimizing side reactions. 2. The flow rate control of the inlet gas and feed affects the residence time (τ) in the reactor, thus affecting the sufficiency of the gas-solid phase reaction. The relationship between residence time and flow rate generally follows the formula: V is the effective volume of the reactor, and Q is the volumetric flow rate of the inlet / feed. A shorter residence time may lead to incomplete reaction, while an excessively long residence time may result in the formation of byproducts. The inlet and feed flow rates need to be optimized based on the reactor size, reaction rate, and target yield of the reaction products. Interface design, especially the contact area and structure between the electrode and electrolyte, has a significant impact on the effectiveness of the reaction. The reaction rate is typically related to the effective surface area A of the electrode. eff The rate of gas-solid phase electrochemical reactions is directly proportional to the rate of mass transfer, which can be enhanced by improving interfacial activity or optimizing structural design. The rate of mass transfer is also limited by the mass transfer process, particularly the diffusion of reactants and products between the electrode and the reactant gas phase. The mass transfer rate is often described by the Sherwood number (Sh) and the Peckley number (Pe). K m Where L is the mass transfer coefficient, D is the characteristic length, and U is the diffusion coefficient, and U is the flow rate, the gas flow rate and reactor design need to be balanced to ensure that the mass transfer rate and reaction rate are matched. Compared with traditional thermocatalytic hydrogenation upgrading methods, the biomass pyrolysis steam in this 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, which can utilize redundant wind, solar and hydropower, significantly reducing the upgrading cost. The successful implementation of this invention is expected to break through the bottleneck problem of complex and costly processes for preparing high-value fuels from biomass pyrolysis, and will help promote the industrial application of high-value utilization technology of biomass pyrolysis.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] (1) In this invention, SOEC electrolysis for hydrogen production is coupled with biomass pyrolysis for hydrogenation. The SOEC used has higher energy efficiency because it operates at high temperatures (typically between 500°C and 850°C), allowing external heat energy to directly participate in the electrolysis reaction, thus reducing the required electrical energy input. Under high-temperature conditions, some reaction energy is provided by heat, resulting in lower voltage requirements and higher energy utilization, making the hydrogenation and upgrading system of this invention more energy-efficient. The SOEC can utilize waste heat from industrial processes or thermal energy from renewable energy sources (such as solar energy) to heat the electrolytic cell. This "thermoelectric synergy" not only reduces external power 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. Furthermore, the reaction rate in low-temperature electrolysis (such as PEMEC and alkaline electrolytic cells) is limited by temperature, resulting in lower hydrogen production efficiency. The operating characteristics of SOEC mean that this system does not require an external hydrogen source, and the high-temperature operating conditions help to increase hydrogen production. This system can directly utilize redundant wind, solar, and hydropower to produce hydrogen, making it very suitable for large-scale hydrogenation and upgrading industries.

[0041] (2) The novel process of this invention, through system design and simplified process flow, enables reactions to be carried out under catalyst-free conditions, avoiding problems such as short catalyst life, easy coking and deactivation, catalyst regeneration or replacement, low yield of upgraded bio-oil, and low H / C ratio. This differs from the expensive and condition-sensitive metal catalysts required for traditional hydrocracking, greatly improving the economic feasibility of high-value utilization of biomass pyrolysis. Furthermore, this system can be widely adapted to various biomass feedstocks, improving the universality and application scope of the process, and helping to promote the industrial promotion and market application of biomass pyrolysis technology.

[0042] (3) This invention couples SOEC electrolysis hydrogen production with biomass pyrolysis hydrogenation technology. The design, using an air pump to drive the pyrolysis gas into the hydrogenation reactor, allows the biomass pyrolysis steam to be directly upgraded online without condensation into crude bio-oil, successfully avoiding the condensation and reheating steps of traditional processes. This design not only makes the reaction conditions milder and the device structure simpler, but also optimizes the feeding process by combining the pyrolysis temperature with the SOEC operating temperature, significantly reducing energy consumption. Through more efficient resource utilization and energy conversion, this system effectively reduces the cost of producing high-value fuels from biomass pyrolysis, bringing significant economic advantages for industrial applications.

[0043] (4) The double-layer reaction channel designed in this invention enables the feed stream and reaction product stream to move countercurrently within the same chamber of the reactor. This ensures that a concentration gradient is maintained between the reactants (such as hydrogen and pyrolysis gas) and the reaction products (such as partially upgraded bio-oil), guaranteeing mass transfer and reaction rate. In the countercurrent configuration, the contact between the reactants and product streams is more precise and controllable, reducing unnecessary side reactions, especially at high temperatures, and preventing the formation of coke or other undesirable byproducts. This design helps improve the upgrading effect of bio-oil and the purity and quality of the final product.

[0044] (5) The countercurrent design is well-suited for continuous reaction processes, allowing reactants and products to flow continuously without frequent feed and discharge adjustments. Current electrochemical hydrogenation processes typically operate in a low-temperature liquid-phase system, requiring crude bio-oil to be miscible with the electrolyte and separated from it after upgrading. This not only increases costs but also limits the processing to the aqueous components of crude bio-oil. Liquid-phase electrocatalytic hydrogenation reactions are time-consuming, typically requiring over 4 hours to reach the target conversion rate. Such methods require batch processing, making continuous production difficult and resulting in poor compatibility with upstream biomass pyrolysis oil production processes. This system enables continuous hydrogenation and deoxygenation of crude bio-oil, which is particularly important for industrial-scale online deep hydrogenation and upgrading, improving the overall process efficiency and economics. The countercurrent operation also reduces the required reactor volume, allowing for a more compact design, saving space and material costs, and consequently reducing capital expenditures and maintenance expenses in industrial applications.

[0045] (6) This invention employs an SOEC electrolyzer and a single electrolyzer structure. This design allows for better control of the gas flow distribution, creating reaction conditions similar to a continuous stirred tank reactor. This avoids the problems of uneven gas flow and incomplete reaction that may occur in dual electrolyzers, ensuring that all pyrolysis gases are in full contact with the reaction interface, thereby optimizing hydrogen utilization and achieving online deep hydrogenation and upgrading of bio-oil. While ensuring the required hydrogen production, the single electrolyzer structure effectively avoids concentration polarization and activation polarization phenomena that may occur in dual electrolyzer designs. The single electrolyzer can maintain high-efficiency reactions under a wider range of reaction conditions, adapting to more diverse raw materials and operating conditions, and improving the system's scalability and applicability.

[0046] Furthermore, the single electrolyzer design optimizes the hydrogen reaction sites and creates a single hydrogen concentration gradient, further enabling the gradient diffusion-gradient reaction process of the pyrolysis gas. Hydrogen concentration gradient control facilitates dynamic regulation during the reaction, resulting in a more balanced and efficient reaction between hydrogen and pyrolysis gas. This innovative design significantly improves reaction selectivity, ultimately exceeding 97%. This technological innovation allows for the stable operation of continuous hydrogenation reactions with higher selectivity and efficiency, and significantly enhances the overall performance and stability of the reactor. Attached Figure Description

[0047] Figure 1 is a schematic diagram of an integrated coupled quality improvement system for biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC.

[0048] Figure reference numerals: 1 Steam generator; 2 Mass flow meter; 3 Heating pipe a; 4 Inlet pipe a; 5 SOEC; 6 Heating furnace; 7 Hollow reaction tube; 8 Feed pipe b; 9 Electrochemical workstation; 10 Heating pipe b; 11 Rapid pyrolysis furnace; 12 Air pump; 13 Heating pipe c; 14 Discharge pipe; 15 Cooling system; 16 Gas bag.

[0049] Figure 2 shows the GC-MS analysis image of the integrated coupled upgrading product of biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC in Example 1. Raw material: pine biomass pellets.

[0050] Figure 3 shows the GC-MS analysis image of the integrated coupled upgrading product of biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC in Example 2. Raw material: redwood biomass pellets.

[0051] Figure 4 shows the gas chromatography-mass spectrometry (PY-GC-MS) analysis image of the pine biomass pellets of Comparative Example 1 after pyrolysis. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0053] A biomass pyrolysis steam electrochemical hydrogenation saturated deoxygenation integrated coupled quality improvement system based on SOEC, as shown in Figure 1, includes: 1. Steam generator; 2. Mass flow meter; 3. Heating pipe a; 4. Inlet pipe a; 5. SOEC; 6. Heating furnace; 8. Feed pipe b; 7. Hollow reaction tube; 9. Electrochemical workstation; 10. Heating pipe b; 11. Rapid pyrolysis furnace; 12. Air pump; 13. Heating pipe c; 14. Discharge pipe; 15. Cooling system; 16. Gas bag.

[0054] SOEC 5 has a sandwich structure, consisting of an SOEC air electrode, an electrolyte electrode, and a fuel electrode from top to bottom. The air electrode is the La... 0.6 Sr 0.4 Co0.2 Fe 0.8 O 3-δ -BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ;

[0055] The electrolyte is BaZr. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ;

[0056] The fuel mentioned is Nio-BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ;

[0057] The SOEC5 is fixed inside the heating furnace 6 via a hollow reaction tube 7. An air inlet pipe a4 is provided above the air electrode of the SOEC5 to connect to the steam generator 1, and a feed pipe b8 is provided below the fuel electrode of the SOEC5 to connect to the rapid pyrolysis furnace 11. The feed pipe b8 is located inside the hollow reaction tube 7, forming a double-layer reaction channel.

[0058] Steam generator 1 is connected to the air electrode of SOEC 5 via an air inlet pipe a4 wrapped with heating pipe a3; the lower end of the air inlet pipe a4 is 1.0-1.5 cm away from the air electrode of SOEC 5. The water vapor generated by steam generator 1 is introduced into the air electrode.

[0059] 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 preheating part of the feed pipe b8 in the heating furnace 5 is 35 cm long.

[0060] After the biomass feedstock is pyrolyzed in the rapid pyrolysis furnace 11, it is separated by a gas-liquid separator. 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. The electrochemical workstation 9 applies voltage to the SOEC5. The water vapor delivered by the steam generator 1 is electrolyzed on the surface of the air electrode to generate hydrogen protons. After passing through the electrolyte, it enters the fuel electrode side and undergoes a gas-solid phase electrochemical hydrogenation and upgrading reaction with the gas from the rapid pyrolysis furnace 11 after pyrolysis of biomass. The resulting reaction product flows downward from the space between the hollow reaction tube 7 and the feed pipe b8 in the double-layer reaction channel. It moves in a countercurrent manner with the pyrolyzed gas in the same chamber, thereby forming the conditions of a continuous stirred tank reactor to realize the online deep hydrogenation and upgrading of bio-oil.

[0061] The rapid pyrolysis furnace 11 is connected in parallel with an air pump 12, which continuously pumps air into the feed pipe b8, driving the pyrolysis gas to the fuel electrode of SOEC5.

[0062] The bottom of the hollow reaction tube 7 extends out of the heating furnace 6 and is connected to the discharge pipe 14 on its side wall. The hydrodeoxygenation product is output from the hollow reaction tube 7 through the discharge pipe 14 wrapped by the heating pipe c13 to the cooling system 15, and the gaseous product is collected by the gas bag 16.

[0063] O2 generated by the electrolysis of water vapor on the air electrode surface diffuses into the heating furnace chamber 6, increasing the oxygen partial pressure of the air electrode and balancing the partial pressure of the fuel electrode caused by the feed flow, thus ensuring the normal progress of the electrochemical reaction.

[0064] The technical solution of this application will be described in detail below with reference to specific embodiments. Unless otherwise specified, the raw materials and equipment used in each embodiment are conventional raw materials and equipment in the field. For example, nano graphite powder can be Alfa's APS 7-11 micron, 99% commercially available product.

[0065] Example 1

[0066] I. Preparation of Solid Oxide Electrolyte (SOEC)

[0067] NiO and BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (This mixture can be a commercially available product or prepared using methods reported in existing literature. In this embodiment, reference DOI:10.1016 / j.jpowsour.2011.08.047 describes a solid-state method.) The mixture is prepared by mixing the powders at a mass ratio of 6:4, followed by the addition of 10 wt.% nano-graphite powder to the total mass of the resulting mixture, yielding composite fuel electrode powder. 0.30 g of the composite fuel electrode powder is weighed and poured into a 12 mm diameter pressing mold to obtain the composite fuel electrode substrate. 0.09 g of BaZr... 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ Electrolyte powder was sprinkled onto a composite fuel electrode substrate and uniaxially co-pressed at 100 MPa for 60 s. After depressurization and demolding, a semi-electrolytic cell green was obtained. Calcination in air at 1300 °C for 6 h sintered the electrolyte to achieve density, resulting in a fuel electrode-supported semi-electrolytic cell.

[0068] electrolyte powder BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δwith La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (The powder can be a commercially available product or prepared using methods reported in existing literature. In this embodiment, reference DOI:10.3390 / ma17040869 describes the preparation using the sol-gel method.) The powders are mixed at a mass ratio of 7:3 to obtain composite air electrode powder. The obtained composite air electrode powder is mixed with 6wt% ethyl cellulose-terpineol binder at a mass ratio of 1:1.5 to prepare a composite air electrode slurry. The obtained composite air electrode slurry is uniformly coated on the electrolyte side of the fuel electrode supporting semi-electrolyte cell and calcined in air at 1000°C for 1 hour to obtain a complete SOEC. The SOEC is fixed to the top of the feed pipe b 7 using high-temperature ceramic adhesive.

[0069] II. Integrated Coupling and Quality Improvement of Biomass Pyrolysis Steam Electrochemical Hydrogenation and Saturated Deoxygenation

[0070] 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 material. Before upgrading, the raw material is placed in an oven and dried at 120°C, weighed every 5 hours, until the mass of the pine biomass pellets no longer changes, for a total drying time of 50 hours.

[0071] 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. Heating pipe a3 heats the air inlet pipe a4 at a temperature of 220℃ to prevent condensation. The water vapor is introduced into the air electrode of SOEC5, and the lower end of the air inlet pipe a4 is controlled to be 1.0 cm away from the air electrode of SOEC5.

[0072] S2: Heating furnace 6 heats SOEC5 to 700℃ at a heating rate of 8℃ / min;

[0073] S3: Electrochemical workstation 9 applies a constant voltage to SOEC5, maintaining the voltage at 1.3V, causing SOEC5 to enter electrolysis mode, and a large number of hydrogen protons are produced at the fuel electrode at the lower end of SOEC5.

[0074] S4: Pine biomass pellets dried for 50 hours are pyrolyzed in a rapid pyrolysis furnace 11 (the temperature is raised to 500℃ at a rate greater than 10000℃ / s and held for 1 second to complete the rapid pyrolysis). Without cooling, the pellets are directly fed into the fuel electrode of SOEC5 through feed pipe b8. The upper end of feed pipe b8 is 1.5cm away from the fuel electrode of SOEC5. The temperature of heating pipe b10 is 300℃ to prevent condensation. Before the reaction, the pyrolysis furnace needs to be continuously purged with nitrogen at a rate of 0.2L / h at room temperature for 0.5h.

[0075] S5: Air pump 12 continuously pumps air into feed pipe b8 at a flow rate of 55 mL / min, driving the pyrolysis gas to the fuel electrode of SOEC5;

[0076] S6: The feed flow flows perpendicular to the fuel electrode region in the feed pipe b8, and the upper port of the feed pipe b8 is controlled to be 1.0 cm away from the fuel electrode of SOEC 5. The pyrolysis gas undergoes a gas-solid phase electrochemical hydrogenation and 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 the conditions of a continuous stirred tank reactor.

[0077] S7: The reaction product is transported from the discharge pipe 14 to the cooling system 15 to obtain the condensed liquid product, and the heating pipe c12 has a heating temperature of 120℃.

[0078] S8: Non-condensable gas is collected by gas bag 16.

[0079] Example 2

[0080] I. Preparation of Solid Oxide Electrolyte (SOEC)

[0081] Step (1) is the same as in Example 1 to obtain a solid oxide electrolytic cell.

[0082] II. Integrated Coupling and Quality Improvement of Biomass Pyrolysis Steam Electrochemical Hydrogenation and Saturated Deoxygenation

[0083] Biomass feedstocks include wood processing residues, forestry logging residues, and crop straw agricultural residues. In Example 2, purchased redwood biomass pellets were used as the biomass feedstock. Before upgrading, the feedstock was placed in an oven and dried at 120°C, weighed every 5 hours until the weight of the redwood biomass pellets no longer changed, for a total drying time of 50 hours.

[0084] 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 the air inlet pipe a4 at a temperature of 250℃ to prevent condensation. The water vapor is introduced into the air electrode of SOEC5, and the lower end of the air inlet pipe a4 is controlled to be 1.5 cm away from the air electrode of SOEC5.

[0085] S2: Heating furnace 6 heats SOEC5 to 650℃ at a heating rate of 5℃ / min;

[0086] S3: Electrochemical workstation 9 applies a constant voltage to SOEC5, maintaining the voltage at 1.4V, causing SOEC5 to enter electrolysis mode, and a large number of hydrogen protons are produced at the fuel electrode at the lower end of SOEC5.

[0087] S4: After the redwood biomass pellets dried for 50 hours are pyrolyzed in the rapid pyrolysis furnace 11 (the temperature is raised to 600℃ at a rate greater than 10000℃ / s and held for 1 second to complete the rapid pyrolysis), they are directly fed into the fuel electrode of SOEC5 through the feed pipe b8 without cooling. The upper end of the feed pipe b8 is 1 cm away from the fuel electrode of SOEC5. The temperature of the heating pipe b10 is 350℃ to prevent condensation. Before the reaction, the pyrolysis furnace needs to be continuously purged with nitrogen at a rate of 0.2 L / h at room temperature for 0.5 hours.

[0088] S5: Air pump 12 continuously pumps air into feed pipe b8 at a flow rate of 60 mL / min, driving the pyrolysis gas to the fuel electrode of SOEC5;

[0089] S6: The feed flow flows perpendicular to the fuel electrode region in the feed pipe b8, 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 and upgrading reaction at the fuel electrode of SOEC5, while the reaction product flow moves in a countercurrent manner in the same chamber, thus forming the conditions of a continuous stirred tank reactor.

[0090] S7: The reaction product is transported from the discharge pipe 14 to the cooling system 15 to obtain the condensed liquid product, and the heating pipe c12 has a heating temperature of 150℃.

[0091] S8: Non-condensable gas is collected by gas bag 16.

[0092] Comparative Example 1

[0093] Pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS) is an analytical method that combines pyrolysis technology with gas chromatography-mass spectrometry. This comparative example uses pine biomass pellets as raw material, and PY-GC-MS is used to analyze the product distribution before hydrogenation. Specific equipment parameters for PY-GC-MS are as follows: the pyrolysis mode is set to flash direct pyrolysis mode. Before the experiment, the quartz pyrolysis tubes are pre-cleaned using a tube furnace and an ultrasonic cleaner, and quartz wool is inserted. A blank sample is used for a preliminary experiment to ensure the analytical system is free of contaminants. High-purity nitrogen is used as the carrier gas at a flow rate of 50 mL / min. The temperature is increased to 700℃ at a rate of 10℃ / ms and held for 15 s. The transfer line temperature is stabilized at 300℃. The pyrolysis products are injected into the GC through a molten silica transfer tube. To reduce and avoid the influence of secondary reactions on the weight loss characteristics, the sample volume is controlled at 1 μL. The chromatographic column used was Restek VMS (inner diameter 30m × 0.25mm, film thickness 1.4μm). The chromatographic temperature conditions were as follows: 40℃ held for 60s, then increased to 240℃ at 8℃ / min and held for 24min. The split ratio was 1:50, the chromatographic interface temperature was 250℃, and the remaining temperatures were controlled at 200℃ to prevent condensation of the pyrolysis products.

[0094] The liquid products obtained in Examples 1-2 were analyzed using gas chromatography-mass spectrometry (GC-MS), and the gas products were analyzed using gas chromatography-flame ionization detector (GC-FID). The GC-MS quantitative methods were the internal standard method and the effective carbon number method. An appropriate reference substance (internal standard compound, here dichloromethane) was added to the sample, and the ratio of the response values ​​of the sample compound and the internal standard compound (called the relative response factor) was calculated. Quantification was performed using this relative response factor and the amount of the added internal standard compound; this is called the internal standard method. The specific calculation can be performed using the following formula:

[0095] Where ω i and ω is The concentrations of the analyte and internal standard compounds are respectively, σ is the relative response factor, and A is the concentration of the analyte and internal standard compounds. i and A is This represents the peak area ratio of the analyte and the internal standard.

[0096] The relative response value used in GC-FID is mainly related to the effective carbon number of the molecule. Therefore, the ratio of the response values ​​of the analyte and the internal standard can be calculated using the effective carbon number method. The effective carbon number method refers to the fact that the relative molar response (RMR) of a substance is directly proportional to the number of carbon atoms in the molecule. That is, the amount of substance of the analyte can be calculated by the following formula:

[0097] As shown in Figure 4, Py-GCMS represents the pyrolysis-gas chromatography-mass spectrometry technique, characterizing the product distribution before hydrogenation, and GC spectra represents the gas chromatogram, characterizing the product distribution after hydrogenation. GC-MS results show that the rapid pyrolysis products in Comparative Example 1 mainly include furan derivatives and small amounts of alkenes and aromatic derivatives. The total content of furan, 2-acetylfuran, and 5-methylfuranaldehyde accounts for more than 80% of the total pyrolysis products, and the pyrolysis products are more complex, with some coking products appearing, and a significant increase in the content of oxygen-containing compounds and aromatics.

[0098] As shown in Figure 2, GC spectra represent gas chromatograms, characterizing the distribution of products after hydrogenation. GC-MS results indicate that the main liquid-phase products after integrated coupled upgrading of biomass pyrolysis steam electrochemical hydrogenation and saturated deoxygenation based on SOEC are monocyclic aromatic hydrocarbons, containing small amounts of furan derivatives and oxygen-containing compounds. Compared to Comparative Example 1, SOEC electrocatalytic hydrogenation in Example 1 significantly upgraded the pyrolysis products, reducing the number of main products from 27 to 12. The proportion of oxygen-containing compounds in the products was significantly reduced, and no polymerization products appeared. The liquid-phase product selectivity for monocyclic aromatic hydrocarbons exceeded 80%, and the deoxygenation rate exceeded 90%.

[0099] As shown in Figure 3, GC spectra represent gas chromatograms, characterizing the distribution of products after hydrogenation. In Example 2, the relative content of furan derivatives increased, while the types and relative contents of polymerization products decreased. Apart from a small amount of α-pyranone obtained from planar hydrogen transfer of vinyl ketone [O=C=CH-CH=CH-CHO], the products contained only monocyclic aromatic compounds, with no other liquid phase substances. The selectivity of the aromatic liquid phase products in Example 2 exceeded 97%, the proportion of oxygen compounds was significantly reduced, and the deoxygenation rate also exceeded 90%.

[0100] Table 1. Calorific value and stability parameters of comparative examples and Examples 1 and 2 after hydrogenation upgrading.

[0101] Table 1 shows that hydrotreating significantly improves the calorific value and stability of bio-oil. The higher heating values ​​of Examples 1 and 2 are 58.2 MJ / kg and 57.4 MJ / kg, respectively, significantly higher than the 17.8 MJ / kg of the comparative example. The lower heating value also increases from 13.1 MJ / kg in the comparative example to 41.7 MJ / kg and 40.2 MJ / kg, respectively. This indicates that hydrotreating can significantly improve the calorific value of bio-oil, approaching the level of traditional fossil fuels. Furthermore, the acid value after hydrotreating decreased from 27.3 mg KOH / g in the comparative example to 10.1-11.3 mg KOH / g, indicating a significant reduction in acidic components and improved chemical stability. Regarding viscosity, the viscosities of Examples 1 and 2 are both between 4.5-4.6 cP, significantly lower than the 15.1 cP in the comparative example, indicating better fluidity of the bio-oil and improved processing and usage performance. Most notably, the oxygen content decreased from 47.2 wt.% in the comparative sample to 3.6-4.2 wt.% after hydrotreating, significantly improving calorific value and combustion performance. Overall, hydrotreating effectively improves the quality of bio-oil, optimizing key parameters such as calorific value, acid value, viscosity, and oxygen content, resulting in better fuel characteristics and industrial application potential.

[0102] Given that current electrochemical hydrogenation of bio-oil is limited to liquid-phase low-temperature hydrogenation systems, continuous operation is difficult, requiring the separation of hydrogenated bio-oil and electrolyte, resulting in low compatibility with upstream biomass pyrolysis processes. This invention utilizes the compatibility of the SOEC (Solar Electrochemical Enzyme Extraction) operating range with biomass pyrolysis to propose an online electrochemical upgrading system and process based on SOEC for biomass pyrolysis steam. This system features mild reaction conditions and a simple device structure, enabling effective electrochemical hydrogenation and deoxygenation under medium temperature, atmospheric pressure, low energy, and highly controllable reaction and input conditions, avoiding the high temperature, high pressure, and complex catalyst requirements common in traditional processes. This not only simplifies the equipment structure and reduces operating costs but also improves process safety and energy efficiency. The mildness is reflected in the fact that, compared to traditional hydrogenation processes, there is no need for high-pressure (>100 MPa) reactions to increase hydrogen solubility and reaction rate in bio-oil. The upgrading process proposed in this invention relies on electrochemical reactions for hydrogenation, eliminating the need for high-pressure hydrogen and enabling operation under atmospheric or low-pressure conditions. This not only reduces the need for complex pressurization equipment but also improves operational safety. Furthermore, the mild reaction conditions are also reflected in the use of SOEC for hydrogenation and upgrading, where the reaction voltage can be precisely controlled via an external electrochemical workstation. This high degree of controllability allows the reaction to proceed with hydrogenation and deoxygenation under controlled energy requirements, avoiding over-reaction and thus reducing unnecessary side reactions, especially coking or cracking. Since SOEC electrochemical reactions primarily rely on the action of solid electrolytes and electrode materials, complex chemical catalysts are unnecessary, as are catalyst regeneration or replacement processes. This differs from the expensive and condition-sensitive metal catalysts required in traditional hydrocracking, significantly simplifying the system's operating conditions and structural design.

[0103] The foregoing has shown and described the basic process, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A biomass pyrolysis steam integrated online upgrading system based on SOEC, the system comprising a steam generator (1), a solid oxide electrolysis cell (SOEC) (5), an electrochemical workstation (9), and a rapid pyrolysis furnace (11), wherein the SOEC (5) has a sandwich structure, consisting of an air electrode, an electrolyte electrode, and a fuel electrode from top to bottom, characterized in that... The SOEC (5) is fixed inside 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 to the steam generator (1). A feed pipe b (8) is provided below the fuel electrode of the SOEC (5) to connect to the rapid 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 steam generated by the steam generator (1) is electrolyzed on the air electrode surface of the SOEC (5) to generate hydrogen protons, which enter the fuel electrode side and react with the gas from the pyrolysis of biomass in the fast pyrolysis furnace (11) to undergo gas-solid phase electrochemical hydrogenation and upgrading reaction. The resulting reaction product flows in the same chamber of the double-layer reaction channel in a countercurrent manner, thereby forming the conditions of a continuous stirred tank reactor to realize the online deep hydrogenation and upgrading of bio-oil. The air electrode and the fuel electrode are respectively connected to the electrochemical workstation (9). The voltage control applied by the electrochemical workstation (9) to the SOEC (5) satisfies the following thermodynamic and kinetic relationship: ΔG=-nFE, where 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 battery electromotive force (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 formula: V is the effective volume of the reactor, and Q is the volumetric flow rate of the inlet / feed.

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

3. The online quality improvement system based on SOEC and integrated coupling of biomass pyrolysis steam as described in claim 1, characterized in that, The rapid pyrolysis furnace (11) enters the fuel electrode of SOEC directly through the feed pipe b (8) wrapped by the 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 SOEC; the length of the preheating part 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). The air pump (12) continuously pumps air into the feed pipe b (8), which drives the pyrolysis gas to the fuel electrode of SOEC.

4. The online quality improvement system based on SOEC and integrated coupling of biomass pyrolysis steam as described in claim 1, 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) to ensure that the reaction product flows in the same chamber of the double-layer reaction channel in a countercurrent manner.

5. The online quality improvement system based on SOEC and integrated coupling of biomass pyrolysis steam as described in 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 gaseous product is collected by the gas bag (16).

6. A biomass pyrolysis-steam integrated online upgrading process based on SOEC using the system described in any one of claims 1-5, characterized in that, Includes the following steps: S1: The steam generated by the steam generator (1) is introduced into the air electrode of SOEC (5) at a flow rate of 80-90 mL / min and a temperature of 200-250℃; S2: The heating furnace (6) heats SOEC (5) to 600-700℃ at a heating rate of 5-8℃ / min; S3: The electrochemical workstation (9) applies a constant voltage to the SOEC (5), maintaining the voltage at 1.3-1.4V, so that the SOEC (5) can start the electrolysis mode and produce a large number of hydrogen protons 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 is directly fed into the fuel electrode of SOEC through the feed pipe b (8); S5: At the same time, control the air flow rate of the air pump (12) into the feed pipe b (8) to be 50-60 mL / min, and drive the pyrolysis gas to the fuel electrode of SOEC; S6: The feed flow input through feed pipe b(8) flows perpendicular to the fuel electrode region. The pyrolysis gas undergoes a gas-solid phase electrochemical hydrogenation and upgrading reaction at the fuel electrode of SOEC. The resulting reaction product flows in the same chamber in a countercurrent manner, thus forming the conditions of a continuous stirred tank reactor. S7: The reaction product is transported from the discharge pipe (14) to the cooling system (15) to obtain the condensed liquid product; S8: Non-condensable gas is collected by the gas bag (16).

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

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

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

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