Electrocatalytic reactor for synthesizing fuel from biomass and molecules derived therefrom

Abstract

The present invention relates to an electrocatalytic reactor for synthesizing fuel from biomass and molecules derived therefrom, comprising an electrolysis unit, an electrolyte circulation unit, and a cooling unit. The electrolysis unit comprises an anode chamber housing, an anode chamber membrane reinforcing piece, a proton exchange membrane, a cathode chamber membrane reinforcing piece, and a cathode chamber housing which are arranged in sequence. The anode chamber housing and the cathode chamber housing are each divided into two communicated chambers by an inwardly recessed cooling water channel on a surface of the housing. The cathode and anode chamber housings are used to accommodate cathode and anode electrolyte liquids and corresponding cathode and anode electrode sheets, respectively. The present invention improves the structure of each component of an apparatus and the arrangement thereof, such that, compared with the prior art, the present invention solves the problems of numerous by-products, unbalanced internal pressure, difficult replacement of electrodes, and complex cooling in an electrosynthesis process. Additionally, the present invention is simple to manufacture and is suitable for mass production of reactors and products thereof.

Description

An electrocatalytic reactor for synthesis of fuels from biomass and its derived molecules TECHNICAL FIELD

[0001] The present invention is in the field of biomass energy utilization, and more specifically, to a design of a reactor for synthesis of low carbon fuels from biomass and its derived molecules using electricity. BACKGROUND

[0002] With the decreasing supply of fossil fuels and the increasing environmental problems, biomass is considered as a promising fuel source. Biomass has high energy storage, clean and renewable, and is a very potential alternative energy. At present, the production of bio-oil, fuel gas, biochar and other products by fast pyrolysis of biomass has become an effective way to utilize biomass resources. However, due to the characteristics of high viscosity, high moisture content, high oxygen content, corrosiveness and chemical instability of bio-oil, its direct application is limited. Therefore, bio-oil should be upgraded by hydration before being used to produce liquid fuels. The traditional hydrogenation and upgrading process is carried out at high temperature. However, bio-oil is prone to polymerization when heated. Due to its thermal instability at high temperature, bio-oil polymerizes to form coke, which blocks the active sites of the catalyst and the reactor, affecting the stability of the upgrading process.

[0003] For the electro-synthesis of fuels, simple electro-synthesis reactors have been demonstrated before. Most of the demonstrations were carried out at laboratory scale. The reactors have been demonstrated to be "membrane-less", or they can use a membrane that exchanges protons (Proton Exchange Membrane, PEM) or hydroxyl ions (Alkaline Exchange Membrane AEM). Most commonly, these electro-synthesis reactors are used to produce hydrogen gas by water splitting reaction, with oxygen as the by-product. Large-scale, industrial-scale water splitting electro-analyzers have been demonstrated and are commercially available. It has recently been demonstrated that syngas (CO and H2) can be synthesized from CO2 and H2 by electro-synthesis, with H2O as the by-product. These demonstrations are usually limited to laboratory scale. There is currently no industrial-scale membrane reactor that can directly utilize electricity to hydrogenate and upgrade bio-derived molecules obtained from biomass. In terms of fuels, this means producing alkanes, alkenes, alcohols or the like from the original molecules of biomass. Here, biomass is defined as any plant or animal matter (such as wood, agricultural waste and by-products, food waste and by-products, municipal solid waste, straw, potato, corn cob, rice husk, etc.) that has recently obtained carbon from atmospheric carbon dioxide, rather than fossil carbon from petroleum products. However, the concept of laboratory-scale demonstration of electrocatalytically driven biomass conversion to increase the value of bio-molecules has been demonstrated in previous studies.

[0004] The typical structure of a membrane reactor in electrocatalytic synthesis is similar to that of a proton exchange membrane fuel cell and / or electrolytic cell. The membrane reactor generally includes: 1) a proton exchange membrane (such as sodium ion), 2) a catalyst material, 3) an electrolyte solution.

[0005] Electrode catalysts are also an important part of the picture, with several materials having been proven and used as catalyst materials. Pure metals include Pt, Ru, Ni, Co, Fe, Cr, Pd, Ir. These pure metals are usually deposited in thin films on a less expensive conductive substrate (such as stainless steel or carbon). Metal particles of various sizes from microns to nanometers are also used as catalysts. These small particles are usually coated on a conductive material or “substrate”. Conductive materials used include stainless steel, carbon (such as graphite, hard / glassy carbon), nickel foam, etc. Metal oxides, metal hydroxides are also used as catalysts, most notably iron hydroxide and nickel doped compounds. These are mainly used for water splitting for hydrogen production, with limited applications in carbon dioxide abatement and biomass upgrading.

[0006] Electrolytes for electrocatalysis can be alkaline, acidic or salt based. The vast majority of electrolytes are alkaline solutions with high pH (>7). These are mainly used for water splitting. Acid catalysis has also been proven at laboratory scale. However, even at laboratory scale, acid catalysis is considered an underdeveloped technology. Electro-catalytic synthesis of fuels and value added chemicals in an acidic environment at industrial scale has not been proven. At industrial scale, alkalinity is usually provided by NaOH or KOH solutions. Alkaline electrolyzers for water splitting are the most mature technology, and these have been applied at industrial scale for the production of green hydrogen, with a significant premium in price over fossil hydrogen.

[0007] Conventional hydrogenation of biologically derived molecules: Molecules from biomass can be converted into useful fuels on appropriate catalysts through a thermal process at high temperature and pressure. This is a hydrogenation process, where typically gaseous hydrogen molecules react with the biological molecules. The gaseous hydrogen molecules are produced separately. The need for gaseous hydrogen limits the opportunity for decarbonization of this standard hydrogenation process, as the cost of green electrocatalytic hydrogen remains too high to enable low commercialization, and is not expected to be competitive for at least the next 7-15 years. Where inexpensive fossil hydrogen (typically from natural gas reforming) can be used to hydrogenate existing hydrocarbons from biomass, this technology can have some minimal commercial penetration. This has been successfully used in the so-called “Hydroprocessed Esters and Fatty Acids” (HEFA) pathway to produce biodiesel fuel blends, with biomass feedstock utilization up to 20%. The process converts fatty acids and biodiesel esters into pure long-chain liquid alkanes through hydrogenation. However, large biomass fractions typically cannot be used in these processes, as their catalysts are converted by fossil fuels and large free fatty acid fractions, with a tendency to cause plugging and fouling in typical processes. These conventional fossil fuel hydrogenation systems have high capital costs (approximately $500 million), and the owners and operators of these systems are typically large fossil fuel companies, who are not willing to process large amounts of biologically derived molecules through existing systems. Neste Corporation is one of the leading companies for biomass hydrogenation, with a large (approximately 1 billion liters / year) biomass hydrogenation plant in Singapore that utilizes fossil hydrogen produced from natural gas reforming. The selling price of this biofuel is still approximately 4 times higher than conventional diesel, primarily due to the relatively high feedstock price, which indicates that this technology cannot enable liquid biofuels to compete with existing fossil fuels. In summary, there are numerous obstacles to manufacturing large amounts of liquid biofuels using conventional hydrogenation technology, and these systems cannot handle large synthetic conversion reactions of biofuels.

[0008] Conversion of biologically derived molecules using electricity in simple reactors has been demonstrated. Molecules that have been converted include vegetable oils, long-chain fatty acids, medium-chain fatty acids, and other various less common molecules. The value-added of the molecules typically converts the molecules into products suitable for use in industries other than energy (pharmaceuticals / healthcare, polymers / plastics, chemicals, etc.). In this context, the molecules are typically deoxygenated and converted into alkanes, alkenes, alcohols, or similar. While there are relatively limited reports of direct conversion of biological molecules into alkanes or alkenes fuels, there have been demonstrations. There are currently no industrial-scale systems suitable for electro-synthesis and conversion of biologically derived molecules into high-quality fuels.

[0009] It is well known that there are many problems with laboratory scale membrane based reactor cases. Among these problems, pressure imbalance leading to membrane strain, thinning, plastic deformation and tearing due to the generation of gas bubbles on one side of the sealed flow cell reactor relative to the other. Membrane fouling due to contact with organics is also considered to be a major problem limiting its application in large scale industrial systems. The reactor cooling method associated with industrial scale systems is also not well developed. Simple methods for replacing and recycling the deactivated catalyst on the electrode have not been well developed and are not well documented.

[0010] In view of the above, we have designed an electrochemical based reactor for the synthesis of low carbon fuels from biomass and its derived molecules under mild conditions. In this process, the bio-oil produced from pyrolysis is not utilized as it requires external energy input and does not produce a uniform, homogenous organic product as described above. Instead, acid hydrolysis is used to hydrolyze cellulose and starch to obtain high and uniform individual molecules, mainly simple carbohydrates / sugars, which can be directly dissolved in aqueous based electrolyte solutions. Subsequently, these sugars are electrocatalytically converted to alkane fuels through various deoxygenation steps. The process involves the use of various electrocatalytic steps to remove oxygen from these cellulose derived molecules. These steps involve the use of corrosion resistant metal (platinum (111), nickel, titanium, alloys) catalysts to remove double bond oxygen and hydroxyl (-OH) groups in the electrolytic media. Subsequently, the use of flat platinum (111) electrodes in alkaline electrolyte media (Kolbe reaction) is used to synthesize molecules with longer carbon chain lengths from the remaining fatty acids. The carbon hydride molecules produced in this process are free of oxygen and are suitable as replacement fuels for diesel and gasoline engines. SUMMARY

[0011] In view of the above deficiencies or improvements in the prior art, the present invention aims to provide an electrocatalytic reactor for the synthesis of fuels from biomass and its derived molecules. The reactor design of the present invention solves the problems of multiple by-products, internal pressure imbalance, electrode replacement difficulty and cooling complexity in the process of electro-synthesis, is simple to manufacture and suitable for batch production of the reactor and its products. The electrocatalytic reactor device comprises an electrolysis unit, an electrolyte circulation unit and a cooling unit, and the components arranged in each unit are connected to each other.

[0012] The electrolysis unit comprises an anode chamber shell, an anode chamber membrane reinforcement sheet, a proton exchange membrane, a cathode chamber membrane reinforcement sheet and a cathode chamber shell, the anode chamber shell and the cathode chamber shell are provided with the anode chamber membrane reinforcement sheet and the cathode chamber membrane reinforcement sheet, and the proton exchange membrane is arranged between adjacent anode chamber membrane reinforcement sheets and cathode chamber membrane reinforcement sheets; the anode chamber shell and the cathode chamber shell are both divided into two cavities in communication by a cooling water groove channel recessed inward from the outer surface of the shell; the anode chamber shell is used for containing an anolyte liquid and internally mounting an anode electrode sheet; the cathode chamber shell is used for containing a catholyte liquid and internally mounting a cathode electrode sheet; the electrolysis unit provides direct current to the anode chamber and the cathode chamber through the anode electrode sheet and the cathode electrode sheet respectively, the anode chamber performs an oxidation reaction to generate oxygen and protons, the protons reach the cathode chamber through the proton exchange membrane, and the dissolved biomolecules in the cathode chamber perform an electrochemical hydrogenation reaction, so as to obtain fuel and value-added chemicals.

[0013] The salt in the electrolyte liquid in the anode chamber can be selected from the commonly used salt in the art to make the electrolyte conduct electricity, and the pH is adjusted by using an acid or a base, and oxygen is released in the anode chamber. The cathode chamber also contains salt and acid or base, but its main function is to contain dissolved biomolecules and make them react, and these biomolecules will be reduced by electrocatalytic analysis. The salt in the electrolyte solution includes but is not limited to Na, K and Mg, sulfate, chloride, acetate and phosphate. The electrolyte on the anode oxidation side and the cathode reduction side is alkaline or acidic and can be selected, and the alkalinity will be provided by a NaOH or KOH solution. The acidity will be provided by an acid, including but not limited to sulfuric acid, acetic acid, phosphoric acid. The electrolyte also includes additives for improving the suspension and / or separation of liquid products, which include methanol, ethanol, acetate, acetate, isopropanol, acetone, choline, glycerol and / or biologically derived by-products in the reactor electrosynthesis process.

[0014] The electrolyte circulation unit comprises electrolyte inlets and outlets located on both the anode chamber housing and the cathode chamber housing, and an electrolyte pumping assembly connecting the electrolyte inlets and outlets in each chamber. The electrolyte pumping assembly connects the electrolyte inlets and outlets in each chamber to circulate the electrolyte through the reactor. Since each chamber has multiple electrolyte inlets and outlets on the side, to take advantage of the chamber cavity structure, the electrolyte inlets and outlets are specified to come from different chambers separated by the cooling water channels in the corresponding chamber. The electrolyte pumping assembly is located outside the electrolysis unit and includes a cathode electrolyte pumping assembly and an anode electrolyte fluid pumping assembly. The device contains at least one electrolyte peristaltic pump (e.g., a high-performance liquid chromatography "HPLC" pump) and a container for storing different electrolytes. The pumping assembly connects the electrolyte inlets and outlets of the cathode chamber housing to move the electrolyte fluid through the reactor, which allows unreacted biomolecules to enter the electrocatalytic reactor chamber through the inlet and enter the subsequent separation and purification process through the outlet. The electrolyte inlet of the anode chamber is connected to the electrolyte outlet by the anode electrolyte fluid pumping assembly to form a circulation loop. Purified water (e.g., deionized water, distilled water) is added to this circulation loop to make up the water used in the electrocatalytic process, which converts water into oxygen and protons.

[0015] The cooling device comprises a cooling water channel recessed inwardly on the surface of the anode chamber housing and the cathode chamber housing, a cooling water inlet and a cooling water outlet at both ends of the cooling water channel, and a corresponding anode cooling water channel cover and a cathode cooling water channel cover on the upper part of the cooling water channel. The cooling unit is used to cool the electrode sheets in the anode and cathode chambers. Since the reactor is a symmetrical structure, this example is described for the anode, and the cathode structure and function are the same, so they will not be described again. The cooling unit is used to cool the anode electrode sheets in the anode chamber. Water enters the cooling water inlet, flows through the cooling water channel, and exits from the cooling water outlet. A separate water circulation unit connects the cooling water inlet and outlet in a closed loop, passing through a chiller that reduces the heat in the water flow. The material at the bottom of the cooling water channel that contacts the electrode plate has the smallest thickness to ensure good thermal contact with the electrode material on the opposite side of the channel. This is to reduce the temperature of the electrode, and the benefit is that lower temperatures reduce the amount of byproducts in the electrocatalytic process. At high flow rates, a large amount of current is discharged through the electrolyte. Since the electrolyte is the part of the path through the reactor that has the most resistance to current flow, it naturally heats up when a large amount of power passes through it at a high flow rate suitable for industrial processes. This feature improves the yield of the desired fuel by allowing the dissolved biomolecules to undergo electrochemical hydrogenation under pre-set temperature conditions.

[0016] The conductive path connects from the anode electrode through the power supply bolt, and connects the cathode electrode through a similar bolt. The electrodes then provide energy through the conductive electrolyte solution, through the proton exchange membrane to the cathode electrode.

[0017] Further, the cooling water channel is square, and the cathode chamber and the anode chamber surrounded by the cooling water channel and the anode / cathode chamber shell are inner grooves with square grooves, which are anode / cathode liquid flow chambers, respectively. The anode / cathode electrolyte inlet is located at the lower half of the side of the inner groove, and the electrolyte outlet is located at the upper half of the side of the inner groove. The electrolyte inlets and outlets of the anode chamber and the cathode chamber are located on both sides of the chamber, and the electrolyte inlets and outlets of the anode chamber and the cathode chamber do not interfere with the connection of the outer pipe. In addition, the electrolyte outlets, electrolyte inlets, cooling water outlets, and cooling water inlets on both sides of the cathode chamber and the anode chamber are designed with threaded openings. This design allows flexible adjustment of the closed and open states of the outlets according to specific use requirements. When discharge (gas or liquid) is needed, the outlets can be opened by loosening the sealing bolts; and in the case of no discharge (gas or liquid), the outlets can be tightly closed by tightening the sealing bolts.

[0018] Further, the anode chamber and the cathode chamber are provided with a labyrinthine turbulent structure at the bottom, which causes local backflow of the anode / cathode liquid in the reaction cavity, improves the uniformity of the liquid in the cavity, and prolongs the reaction time of the liquid on the surface of the electrode.

[0019] Further, the middle part of the inner groove of the anode / cathode chamber is provided with outwardly recessed parallel strip-shaped bands with a certain spacing. The direction of the strip-shaped bands is perpendicular to the axial direction of the cooling water channel. The strip-shaped bands are installed with adaptive anode / cathode electrode sheets. The size range of the electrode sheets is 5-50mm in width, 0.1-3mm in thickness, and 50-1250mm in length. The spacing between the electrodes is 3-5cm, so as to improve the efficiency of electrocatalysis. The anode / cathode electrolyte gap layer is reserved between the anode / cathode electrode sheets and the anode / cathode chamber membrane reinforcing sheets, so that the electrolyte can pass through. For the cathode, the biomolecules suspended in the water-based electrolyte solution fill the inflow cavity and continue to enter the electrolyte gap layer. The current is applied to remove oxygen in the biomolecules in contact with the electrode, and the catalyst on the electrode adds hydrogen to the molecules, removes oxygen, and produces water as a product.

[0020] Further, the membrane reinforcement sheet of the cathode and anode chamber is perforated at the position opposite to the gap layer of the cathode and anode electrolyte, to allow contact with the electrolyte solution. After the bio-molecules are converted in the electro-catalytic channel, the electrolyte solution with the converted molecules flows into the overflow chamber and out of the reactor. The converted molecules are more hydrophobic or insoluble in water than the original bio-molecules, and can be easily separated from the water-based electrolyte. The easy separation of the fuel product is another advantage of this design. Gravity-assisted separation and membrane protection can be directly combined here, and the direction of the reactor housing unit can be tilted to prevent the hydrophobic molecules from contacting the electrodes or membranes.

[0021] Further, a bi-directional pressure valve is provided on the top of the cathode and anode chamber housing, and a liquid outlet is provided on the bottom. A bi-directional pressure valve is provided on the top of the chamber to regulate the pressure during the electro-catalytic process, and can be inflated or deflated according to the pressure balance needs. The pressure changes due to the evolution of gas during the hydrogenation of bio-molecules. The gas produced during the reaction (H2, CO2) can be easily adjusted by the bi-directional pressure valve to regulate the pressure. The flow and pressure of the overflow chamber can be adjusted to ensure that there is always gas in the overflow chamber, and no liquid contacts the bi-directional pressure valve. Through the bi-directional pressure valve, these gases can be collected and stored, or transported to further processes to produce more fuel (for example, electro-catalytic reduction of carbon dioxide and Fischer-Tropsch synthesis of fuel). The oxygen evolved can also be collected through the overpressure / pressure relief valve on the opposite side of the proton exchange membrane, which is configured and functions the same as the valve on the reduction side. Most reactors do not describe gas collection, so this is also an important improvement over traditional reactors.

[0022] Further, the cooling unit is water flowing through the reactor channel in close contact with the back of the electrode material, and the cathode and anode chamber housing is equipped with a thermocouple and an electronic thermostat to monitor the temperature of the reactor according to the settings on the cooler, and the thermocouple is used to detect the temperature of the electrolyte solution in the cathode and anode chamber housing, and the thermostat is used to control the output power of the water chiller according to the temperature detected by the thermocouple, and to change the power of the heating resistance wire in the cathode and anode chamber to control the temperature of the electrolyte in the cathode and anode chamber.

[0023] Further, in terms of materials or materials, the reactor system is composed of two parts, separated by a perforated rigid plate reinforced membrane. The membrane will exchange protons, and is generally a commercial Nafion exchange membrane (brand: DuPont). The reactor half-plate and the main body will be made of stainless steel, aluminum or rigid and / or thermosetting polymers, including glass, nylon, polytetrafluoroethylene or similar materials. The design of the body itself can withstand a pressure of up to 120 pounds. The reactor contains narrow channels a few millimeters wide, through which the reactants suspended in the electrolyte will flow.

[0024] The electrode substrate will be made of stainless steel or graphite and coated with a catalyst material. The catalyst material will consist of metals including but not limited to Pt(111), Co, Ni, Cu, Al, Zn, Pd, Ir, Sn, In, Mn, Fe, Sr, La, Ga, Mo, W, Ag, B, Ti, V, Bi, Pb. Alloys, combinations of these metals, for example combinations of copper, aluminum and nickel. Compounds of these metals including but not limited to oxides, hydroxides, hydroxides, sulfides, oxysulfides, nitrides, oxynitrides, phosphides, oxophosphides, phosphates, borates, borohydrates, fluorides or similar substances. High surface area electrodes can be used including metal foams. Nanomaterials and complex nanocomposites of the above materials can be utilized. The electrodes can also be mounted directly on perforated separation / reinforcement sheets on the membrane. This facilitates separation of products or organics in the lighter layer with less density on top of the channel.

[0025] The applied current density is between 50mA / cm 2 and 500mA / cm 2 .

[0026] The purpose of the flow is to have the velocity of the laminar flow between 1 cm / s and 10 cm / s through the channel.

[0027] The bidirectional pressure valve will maintain the pressure on both sides of the membrane at a constant value between 0.4 Mpa and 3 MPa. It is this regulation of pressure that avoids the pressure imbalance leading to membrane strain, thinning, plastic deformation and tearing.

[0028] The reactor operates between the freezing point and the boiling point of the electrolyte (-4-100°C).

[0029] Further, the reactor of the present invention is applied to synthesize fuels and value-added chemicals from biomass and biologically derived molecules, the biomass being any plant or animal matter that has recently obtained carbon from carbon dioxide in the atmosphere (for example, wood, agricultural waste and by-products, food waste and by-products, municipal solid waste, straw, potato, corn cob, rice husk, etc.). The biomass is subjected to acid hydrolysis to obtain a uniform single biomolecule raw material, and the biomolecules obtained by hydrolysis include simple anhydrous compounds / sugars (such as glucose, fructose, xylose), furan, 5-hydroxymethylfurfural, cellobiose, mono- and polyols (such as sorbitol), mono- and diacids (such as gluconic acid and gluconic acid), etc. These biomolecules can be directly dissolved in a water-based electrolyte solution. Subsequently, the biomolecule raw material is electrocatalytically converted into alkane fuels through various deoxygenation steps, and the resulting products include saturated fatty acids (such as hexanoic acid), alkanes (such as hexane), olefins (such as hexene), alcohols (such as hexanol).

[0030] By means of the above technical solutions conceived by the present invention, the following beneficial effects can be achieved compared with the prior art:

[0031] Gravity assisted organic separation: The reactor will be adjusted so that gravity will assist in separating the reacted material from the unreacted material, forming a layer of less dense organic material in the channel that will naturally rise from the electrode, reducing the possibility of further electrocatalytic reactions with the electrode material, thus limiting the production of byproducts and increasing selectivity.

[0032] Pressure balancing: A simple bi-directional pressure valve will be used to balance the pressure on both sides. The pressure on the oxygen evolution electrode side will be generated by the production of oxygen gas bubbles, supplemented by a compressor as needed. The pressure on the biomolecule hydrogenation side will be generated by a compressor, supplemented by H2 and any gaseous products such as simple volatile hydrocarbons (CH4, CO, formate, etc.).

[0033] Simple electrode replacement logic: Since the electrodes can be detached and embedded in the body, and can be detached into different reactors with low manufacturing cost, the electrodes can be easily removed and replaced in the design.

[0034] Simplified electrode cooling: The electro-synthesis reactor can consume a large amount of electricity in use. Therefore, this design actively cools the electrodes by flowing cooling water through the back of the electrode channel in a simple way. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is an exploded view of a single reactor.

[0036] Figure 2 is an external view of a single reactor.

[0037] Figure 3 is a perspective view of the membrane and perforated reinforcement sheet.

[0038] Figure 4 is a water cooling channel and various inlets / outlets.

[0039] Figure 5 is a side view of half a reactor.

[0040] Figure 6 is an angular view of the internal structure of the reactor.

[0041] Figure 7 is a bottom view of the reactor housing.

[0042] Figure 8 is a schematic diagram of the reactor: a) bottom, b) side, c) top view.

[0043] Figure 9 is a schematic diagram of the reactor channel: a) side view, b) end view.

[0044] Figure 10 is a raw material molecule, cellulose and hemicellulose and their derivatives.

[0045] Figure 11 is a schematic diagram of the electrolyte flow in the cathode and anode chambers: a) cathode chamber for biomolecule reduction reaction; b) anode chamber for oxygen production.

[0046] Figure 12 is a schematic diagram of the electrical connection of the reactor chamber, anode and cathode.

[0047] The meanings of the reference numerals in Figures 1-12 are as follows: 1 - anode cooling water tank cover, 2 - anode chamber shell, 3 - anode chamber membrane reinforcing sheet, 4 - proton exchange membrane, 5 - cathode chamber membrane reinforcing sheet, 6 - cathode chamber shell, 7 - cathode cooling water tank cover, 8 - reinforcing sheet perforation, 9 - electrolyte inlet, 10 - electrolyte outlet, 11 - cooling water inlet, 12 - cooling water outlet, 13 - cooling water tank passage, 14 - electrode bolt hole, 15 - gas vent, 16 - anode electrode sheet, 17 - liquid discharge port, 18 - anode electrode liquid gap layer, 19 - outflow cavity, 20 - inflow cavity, 21 - cathode electrode liquid gap layer, 22 - cathode electrode sheet, 23 - bidirectional pressure valve, 24 - biomass raw material acidolysis tank, 25 - fractional distillation purification tank, 26 - electrolyte pumping assembly, 27 - conductive bolt, 28 - power supply. DETAILED DESCRIPTION

[0048] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0049] As shown in Figures 1-2, the present embodiment provides an electrocatalytic reactor for synthesizing fuel from biomass and its derived molecules, which comprises an electrolysis unit, an electrolyte circulation unit and a cooling unit, and the components arranged in each unit are connected to each other, wherein: the electrolysis unit comprises an anode chamber shell 2, an anode chamber membrane reinforcing sheet 3, a proton exchange membrane 4, a cathode chamber membrane reinforcing sheet 5 and a cathode chamber shell 6, the anode chamber shell 2 and the cathode chamber shell 6 are provided with the anode chamber membrane reinforcing sheet 3 and the cathode chamber membrane reinforcing sheet 5, and the adjacent anode chamber membrane reinforcing sheet 3 and cathode chamber membrane reinforcing sheet 5 are provided with the proton exchange membrane 4;

[0050] As shown in Figure 4, the anode chamber shell 2 and the cathode chamber shell 6 are each divided into two cavities in communication by a cooling water tank passage 13 which is recessed inward from the outer surface of the shell;

[0051] As shown in Figures 6 and 9, the anode chamber shell 2 is used to contain anode electrolyte liquid and is internally provided with an anode electrode sheet 16; the cathode chamber shell 6 is used to contain cathode electrolyte liquid and is internally provided with a cathode electrode sheet 22; the electrolysis unit provides direct current to the anode chamber and the cathode chamber through the anode electrode sheet 16 and the cathode electrode sheet 22 respectively, the anode chamber performs oxidation reaction to produce oxygen and protons, the protons reach the cathode chamber through the proton exchange membrane, and the dissolved biomolecules in the cathode chamber perform electrochemical hydrogenation reaction;

[0052] As shown in Fig. 4, Fig. 11, the electrolyte circulation unit includes electrolyte inlet 9, electrolyte outlet 10 and electrolyte pumping assembly 26 arranged on both anode chamber shell 2 and cathode chamber shell 6, electrolyte pumping assembly 26 connects electrolyte inlet 9 and electrolyte outlet 10 in anode and cathode shells, electrolyte inlet 9 and electrolyte outlet 10 are from different chambers in the corresponding shell separated by cooling water channel, electrolyte is circulated through the reactor. The cooling device includes cooling water channel 13 arranged in anode chamber shell 2 and cathode chamber shell 6, cooling water inlet 11 and cooling water outlet 12 located at both ends of cooling water channel 13, and anode cooling water channel cover 1 and cathode cooling water channel cover 7 located at the upper part of cooling water channel 13.

[0053] As shown in Fig. 5- Fig. 6, the cooling water channel 13 is square, the cathode chamber and anode chamber surrounded by the cooling water channel 13 are inner square grooves, the inner square grooves are anode and cathode liquid flow chambers respectively, anode and cathode electrolyte inlets are located at the lower half of the side of the inner square grooves, and anode and cathode electrolyte outlets are located at the upper half of the side of the inner square grooves, the electrolyte inlets and electrolyte outlets of the anode chamber and the cathode chamber are located at both sides of the chamber, and the electrolyte inlets and electrolyte outlets of the anode chamber and the cathode chamber do not interfere with the connection of the outer pipe. In addition, the electrolyte inlets, electrolyte outlets, cooling water outlets and cooling water inlets on both sides of the cathode chamber and the anode chamber are designed with threaded openings, according to the need for discharge (gas or liquid), when discharge (gas or liquid) is needed, the outlets can be opened by loosening the sealing bolts; and in the case where discharge (gas or liquid) is not needed, the outlets can be tightly closed by tightening the sealing bolts. In particular, the electrode liquid inlet 9 and the gas vent hole 15 can share a threaded opening, which can be used as a rapid venting channel when the pressure in the chamber is high and emergency venting is needed.

[0054] The bottom of the anode chamber and the cathode chamber is provided with a labyrinthine turbulent structure, which causes local backflow of anode and cathode liquid in the reaction cavity, improves the uniformity of the liquid in the cavity, and prolongs the reaction time of the liquid on the electrode surface.

[0055] As shown in Fig. 6- Fig. 7, the protruding position in the middle of the anode and cathode chamber inner grooves is provided with outwardly recessed parallel strip-shaped bands with a certain spacing, the direction of the strip-shaped bands is perpendicular to the axial direction of the cooling water channel, the parallel strip-shaped bands are installed with adaptive anode and cathode electrode sheets, the size range of the electrode sheets is width 5-50mm, thickness 0.1-3mm and length 50-1250mm, and the spacing between the electrode sheets is 3-5cm. The anode and cathode electrode sheets and the anode and cathode chamber membrane reinforcing sheets are kept apart by an anode and cathode electrolyte gap layer through which electrolyte can pass.

[0056] As shown in Figure 3, the membrane reinforcement sheet is perforated at the position opposite to the anode and cathode electrolyte gap layer, forming a reinforcement sheet perforation 8 to allow contact with the electrolyte solution.

[0057] As shown in Figures 5-6, 8, 11, a bidirectional pressure valve 23 is provided above the anode and cathode chamber housing, and a liquid outlet 17 is provided below the anode and cathode chamber housing. The bidirectional pressure valve 23 can be inflated or deflated according to the pressure balance requirement, and will keep the pressure on both sides of the membrane at a constant value between 0.4 MPa and 3 MPa.

[0058] As shown in Figure 6, the cooling unit is a water flow through the reactor channel 13 in close contact with the back of the electrode material. The anode and cathode chamber housing is equipped with a thermocouple and an electronic thermostat. The temperature of the reactor is monitored according to the setting on the cooler. The thermocouple is used to detect the temperature of the electrolyte solution in the anode and cathode chamber housing. The thermostat is used to control the output power of the water chiller according to the temperature detected by the thermocouple, and to change the power of the heating resistance wire in the cathode chamber to control the temperature of the electrolyte in the cathode chamber.

[0059] As shown in Figure 11, the electrolyte pumping assembly 26 is composed of an HPLC peristaltic pump and an electrolyte storage tank located on the pipeline. After the acid hydrolysis product biomolecules in the biomass raw material acid hydrolysis tank 24 are mixed with the cathode electrolyte, the pumping assembly connects the electrolyte inlet 9 of the cathode chamber housing with the electrolyte outlet 10, so that the electrolyte fluid moves through the reactor, which will make the unreacted biomolecules enter the electrocatalytic reactor chamber through the inlet and enter the subsequent fractionation and purification tank 25 for separation and purification. The electrolyte inlet 10 of the anode chamber is connected with the electrolyte outlet 10 through the anode electrolyte fluid pumping assembly 26, forming a circulating loop. Purified water (such as deionized water, distilled water) is added to this circulating loop to make up the water used in the electrocatalytic process, which will convert water into oxygen and protons.

[0060] As shown in Figure 12, the electrical connection diagram of the reactor chamber, anode and cathode, the power supply 28 is connected to the cathode electrode sheet 22 and the anode electrode sheet 17 through the conductive bolt 27 to carry out the electrocatalytic reaction.

[0061] Standardized, "off-the-shelf" electrical and fluid connection schemes and pressure valves can be used in the structure. The electrode wires and electrical connections will be made through the extension screw connection shown in Figure 4.

[0062] In this example, the electrode sheet substrate will be made of stainless steel or graphite and coated with a catalyst material. One or more of the noble metals such as platinum, gold, palladium, etc. can be used as the cathode catalyst material; one or more of graphite, nickel, iron hydroxide, and nickel-doped compounds can be used as the anode catalyst material. The proton exchange membrane in this example is Nafion-117. Electrolyte preparation: The electrolyte preparation is simple, just add the reactants, salts, organics, etc. to water and adjust the pH with an acid (such as H2SO4, acetic acid, or similar) or base (NaOH, KOH). In this example, the electrolyte is a salt solution, which can be a dilute solution of a single acid or base, or a buffer solution of inorganic salts, such as potassium dihydrogen phosphate and dipotassium hydrogen phosphate, or sodium carbonate and sodium bicarbonate.

[0063] The reactor body will have several ports. The exit for the reaction fuel and electrolyte 10 and the entry for the reactant and electrolyte 9 are shown in Figures 4 and 8. Figure 4 shows several ports to make the design more symmetrical and configurable.

[0064] Gravity feed and product separation: The reactor can be installed in a direction such that the electrolyte channels are perpendicular to the ground, parallel to the vector of gravity, or inclined to the gravity to take advantage of the density difference between the electrolyte channels to separate the electrolyte and the product.

[0065] Electrical connection: Long bolts can be used to connect the electrodes to the reactor housing. A voltage (0.3-5V) can then be applied to the electrodes to obtain a current density between 50-500 mA / cm2.

[0066] Liquid flow and gas collection during operation: The large chamber above and below the electrolyte gap layer 18 is mainly used to separate gas and liquid. In the effluent chamber 19, gas and liquid are separated by the electrolyte outlet 10 to discharge the product molecules (i.e. fuel) suspended in the electrolyte solution. Gas is collected by an overpressure or bidirectional pressure valve 23, as shown in Figure 8.

[0067] Figure 10 shows that the raw material molecules, cellulose and hemicellulose, and their derivatives, after acid hydrolysis of biomass, obtain uniform single biomolecule raw materials, and the hydrolysis of biomolecules includes cellulose, hemicellulose, hexose, hexose acid, pentose, deoxyhexose acid, which are converted into saturated fatty acids (such as hexanoic acid), alkanes (such as hexane), olefins (such as hexene), alcohols (such as hexanol) through the process of electrocatalytic hydrogenation in this reactor. By electrolytic condensation again, the carbon chain length can be extended from C5-C6 to C8-C10 or even longer fuel molecules.

[0068] The reactor has two modes of operation: one is gravity feed without suction, and the other is active suction of fluid through the system. All the liquid in the reactor can be discharged through the liquid discharge port 17.

[0069] If the reactor is run in a gravity feed configuration, the reactants will be introduced into the top chamber and subsequently run down the channel where the electro-synthesis will take place. The gas bubbles (such as H2, O2, CO2, small organic molecules) that are produced by the electro-catalytic process in the reactor channel will be filtered back through the reactant and electrolyte flow, and the gas will collect at the top of the reactor. This gas can be vented out of the reactor and collected through the vent / over-pressure valve at the top of the reactor housing. The bottom chamber can then fill with electrolyte and electro-synthesis products. These products can be collected as they flow out of the bottom of the reactor under the force of gravity. The flow rate can be controlled simply using the pipe diameter and connection restriction as the fluid passes out of the reactor bottom.

[0070] If a pumped reactor is used, appropriate for delivering chemicals and electrolytes of various pH values, the reactants will be introduced into the lower chamber of the reactor. When this lower chamber is full, the reactants will flow up the electro-synthesis channel at a rate determined by the pumping rate. The gases produced during the electro-synthesis process will be collected just as in the case of gravity feed, the only difference being that now they are swept to the top chamber of the reactor with the flow of fluid. The fluid in the top chamber of the reactor contains products and electrolyte. This can be removed from the reactor through connections on either side of the top chamber. These gases are again collected through the over-pressure / vent valve at the top of the reactor housing.

[0071] The gravity fed configuration is attractive because it requires minimal external energy to move the fluid. The pumped configuration can better control the fluid flow rate and can more efficiently collect the gases.

[0072] In both configurations, the pressure will be regulated by the fluid flow rate and the gas compressor connected to the top chamber.

[0073] The design of the reactor in the embodiments improves the management of the gases produced during the electro-synthesis process, can equalize the pressure across the membrane, and can collect the gases under pressure. The design allows for gravity feed and gravity assisted product separation, extends the membrane life by reducing membrane fouling, which is a major problem for membrane reactors that utilize organic species. The embodiments simplify the integrated water cooling that is in close proximity to the electrodes, enabling simple manufacturing that is suitable for mass production of the reactors and their products.

[0074] The above description is only the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An electrocatalytic reactor for the synthesis of fuels from biomass and its derived molecules, characterized by, The application relates to an electrolysis device, which comprises an electrolysis unit, an electrolyte circulation unit and a cooling unit, and components arranged in the units are connected with each other, wherein the electrolysis unit comprises an anode chamber shell, an anode chamber membrane reinforcing sheet, a proton exchange membrane, a cathode chamber membrane reinforcing sheet and a cathode chamber shell, the anode chamber shell and the cathode chamber shell are provided with the anode chamber membrane reinforcing sheet and the cathode chamber membrane reinforcing sheet, and the proton exchange membrane is arranged between adjacent anode chamber membrane reinforcing sheets and cathode chamber membrane reinforcing sheets; the anode chamber shell and the cathode chamber shell are both divided into two cavities which are communicated by a cooling water groove channel which is concave to the inner surface of the shell; the anode chamber shell is used for containing an anode electrolyte liquid and is internally provided with an anode electrode sheet; the cathode chamber shell is used for containing a cathode electrolyte liquid and is internally provided with a cathode electrode sheet; the electrolysis unit provides direct current to the anode chamber and the cathode chamber through the anode electrode sheet and the cathode electrode sheet respectively, the anode chamber carries out oxidation reaction to generate oxygen and protons, the protons reach the cathode chamber through the proton exchange membrane, and the biomass and the derived molecules dissolved in the cathode chamber carry out electrochemical hydrogenation reaction. The electrolyte circulation unit comprises electrolyte inlets and outlets arranged on the anode chamber shell and the cathode chamber shell and an electrolyte pumping assembly, the electrolyte pumping assembly connects the electrolyte inlets and the electrolyte outlets in the anode chamber shell and the cathode chamber shell, and the electrolyte inlets and the electrolyte outlets are respectively from different cavities in the corresponding shells which are separated by the cooling water channel, so that the electrolyte is circulated through the reactor. The cooling device comprises the cooling water groove channels which are concave to the inner surface of the shell in the anode chamber shell and the cathode chamber shell, cooling water inlets and outlets located at both ends of the cooling water groove channels and anode cooling water groove covers and cathode cooling water groove covers located at the upper portions of the cooling water groove channels.

2. The electro-catalytic reactor of claim 1, wherein: The cooling water groove channel is square, the cathode chamber and the anode chamber surrounded by the cooling water groove channel and the anode chamber shell and the cathode chamber shell are inner grooves with square grooves, the inner grooves are anode and cathode liquid flow chambers respectively, the anode and cathode electrolyte inlets are located at the lower half portions of the side surfaces of the inner grooves, the electrolyte outlets are located at the upper half portions of the side surfaces of the inner grooves, the electrolyte inlets and the electrolyte outlets of the anode chamber and the cathode chamber are located at the two sides of the chambers, and the electrolyte inlets and the electrolyte outlets of the anode chamber and the cathode chamber do not interfere with each other when connecting the outer pipes.

3. The electro-catalytic reactor of claim 2, wherein: The electrolyte outlets, the electrolyte inlets, the cooling water outlets and the cooling water inlets on the two sides of the cathode chamber and the anode chamber are designed as threaded openings, the outlets and inlets can be opened by loosening the sealing bolts when discharging is needed, and the outlets and inlets can be tightly closed by tightening the sealing bolts when discharging is not needed.

4. The electro-catalytic reactor of claim 1, wherein: The anode chamber and the cathode chamber are provided with labyrinth turbulent structures at the bottom portions, so that the anode and cathode liquids generate local reflux in the reaction cavities, the uniformity of the liquids in the cavities is improved, and the reaction time of the liquids on the electrode surfaces is prolonged.

5. The electro-catalytic reactor of claim 1, wherein: The parallel strip-shaped bands are outwardly recessed and have a certain interval at the position of the protrusion in the middle of the groove in the cathode and anode chamber. The direction of the strip-shaped bands is perpendicular to the axial direction of the cooling water groove channel. The parallel strip-shaped bands are installed with the adapted cathode and anode electrode sheets. The size range of the electrode sheets is 5-50mm in width, 0.1-3mm in thickness and 50-1250mm in length. The interval between the electrodes is 3-5cm. The cathode and anode electrode sheets and the cathode and anode chamber membrane reinforcing sheets are kept apart by the cathode and anode electrolyte gap layer which allows the electrolyte to pass through.

6. The electro-catalytic reactor of claim 1, wherein: The cathode and anode chamber membrane reinforcing sheets are perforated at the position opposite to the cathode and anode electrolyte gap layer to allow contact with the electrolyte solution.

7. The electro-catalytic reactor of claim 1, wherein: The upper part of the cathode and anode chamber shell is provided with a bidirectional pressure valve, and the lower part is provided with a liquid outlet. The bidirectional pressure valve keeps the pressure on both sides of the membrane at a constant value between 0.4Mpa and 3MPa.

8. The electro-catalytic reactor of claim 1, wherein: The cooling unit is a water flow through the reactor channel in close contact with the back of the electrode material. The cathode and anode chamber shell is equipped with a thermocouple and an electronic thermostat. The temperature of the reactor is monitored according to the settings on the cooler. The thermocouple is used to detect the temperature of the electrolyte solution in the cathode and anode chamber shell. The thermostat is used to control the output power of the water chiller according to the temperature detected by the thermocouple, and the power of the heating resistance wire in the cathode chamber is changed to control the temperature of the electrolyte in the cathode chamber.

9. The electro-catalytic reactor of claim 1, wherein: The electrolyte pumping assembly is composed of an HPLC peristaltic pump and an electrolyte storage tank located on the pipeline. After the acid hydrolysis product biomolecules in the biomass raw material acid hydrolysis tank are mixed with the cathode electrolyte, the pumping assembly connects the electrolyte inlet and outlet of the cathode chamber shell to make the electrolyte flow through the reactor. This will make the unreacted biomolecules enter the electro-catalytic reactor chamber through the inlet and enter the subsequent fractionation and purification tank for separation and purification. The electrolyte inlet of the anode chamber is connected with the electrolyte outlet through the anode electrolyte fluid pumping assembly to form a circulating loop.

10. The electro-catalytic reactor of claim 1, wherein: The cathode and anode electrode sheet substrate is made of graphite and coated with a catalyst material. Platinum is used as the cathode catalyst material, and nickel is used as the anode catalyst material.

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