Liquid fuel production method

Abstract

To provide a liquid fuel production method that can define the feed ratio of hydrogen and steam so that the carbon monoxide amount is increased by hydrogen supply and the H2 / CO ratio after gasification becomes 2 or more.SOLUTION: A liquid fuel production method comprises: a gasification step of generating a synthesis gas from a biomass raw material; an electrolytic step of generating hydrogen from water by electricity generated using renewable energy; a liquid fuel production step of producing a liquid fuel using the synthesis gas generated by the gasification step and hydrogen generated by the electrolytic step; and a controlling step of controlling the gasification step and the electrolytic step, where the masses of the biomass raw material (B) introduced in the liquid fuel production step, steam (S), and hydrogen (H) satisfy the following formulas (1) to (4): H / B≤-0.031×S / B+0.079 (1); H / B≥-0.028×S / B+0.056 (2); S / B≥0.5 (3); and H / B>0 (4).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing liquid fuel. [Background technology]

[0002] In recent years, electrosynthetic fuels, which are made from hydrogen generated using electricity generated by renewable energy sources and carbon sources such as biomass and carbon dioxide emitted from factories, have been attracting attention as an alternative to fossil fuels.

[0003] The general procedure for producing liquid fuels such as methanol and gasoline using biomass as a feedstock is as follows: a gasification process in which biomass feedstock that has undergone a specified pretreatment is gasified together with hydrogen, oxygen, and steam in a gasifier to produce a synthesis gas containing hydrogen and carbon monoxide; a cleaning process in which the synthesis gas that has been produced is cleaned and tar is removed; an H2 / CO ratio adjustment process in which the H2 / CO ratio of the synthesis gas that has undergone the cleaning process is adjusted to a target ratio corresponding to the liquid fuel to be produced; a desulfurization process in which sulfur components are removed from the synthesis gas that has undergone the H2 / CO ratio adjustment process; and a fuel production process in which liquid fuel is produced from the synthesis gas that has undergone the desulfurization process. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-147504 Summary of the Invention [Problem to be solved by the invention]

[0005] In the gasification process, biomass undergoes pyrolysis, producing a mixed gas containing hydrogen, carbon monoxide, carbon dioxide, methane, and other gases. Of the gases produced by pyrolysis, hydrogen and carbon monoxide are used as raw materials for liquid fuel. When producing liquid fuel from hydrogen and carbon monoxide, it is necessary to control the H2 / CO ratio to an appropriate value. If the H2 / CO ratio can be controlled within an appropriate range and the gasifier can be operated under conditions that maximize the amount of carbon monoxide produced within that range, the yield of liquid fuel can be maximized.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a method for producing liquid fuel that increases the amount of carbon monoxide by supplying hydrogen and that can specify the supply ratio of hydrogen to water vapor so that the H2 / CO ratio after gasification is 2 or more, thereby contributing to improved quality control in the production process and ultimately to energy efficiency. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides the following means. [1] A liquid fuel production method for producing liquid fuel from biomass feedstock, a gasification step for producing synthesis gas from biomass feedstock; an electrolysis process that produces hydrogen from water using electricity generated using renewable energy; a liquid fuel production process in which liquid fuel is produced using the synthesis gas produced in the gasification process and the hydrogen produced in the electrolysis process as raw materials; a control step for controlling the gasification step and the electrolysis step, A method for producing a liquid fuel, wherein the mass of the biomass material (B), the mass of the steam (S), and the mass of the hydrogen (H) introduced into the liquid fuel production step satisfy the following formulas (1) to (4): H / B≦-0.031×S / B+0.079 (1) H / B≧-0.028×S / B+0.056 (2) S / B≧0.5 (3) H / B>0 (4)

[0008] The present invention can increase the amount of carbon monoxide by supplying hydrogen, and can specify the supply ratio of hydrogen to steam so that the H2 / CO ratio after gasification is 2 or more. [Effects of the Invention]

[0009] According to the present invention, the amount of carbon monoxide can be increased by supplying hydrogen, and the supply ratio of hydrogen to steam can be specified so that the H2 / CO ratio after gasification is 2 or more. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the configuration of a fuel production system used in a method for producing liquid fuel according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing the results of an experiment investigating the H2 / CO ratio and the amount of liquid fuel produced. [Figure 3] FIG. 10 is a diagram showing the results of an experiment investigating the H2 / CO ratio when S / B and H / B are varied. [Figure 4] This is a graph created based on Figure 3, with the vertical axis representing H / B and the horizontal axis representing S / B. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a method for producing a liquid fuel according to one embodiment of the present invention will be described with reference to the drawings.

[0012] [Fuel production system] FIG. 1 is a diagram showing the configuration of a fuel production system according to one embodiment of the present invention. As shown in FIG. 1, the fuel production system 1 includes a biomass feedstock supply device 2 that supplies biomass feedstock, a gasification device 3 that gasifies the biomass feedstock supplied from the biomass feedstock supply device 2 to produce synthesis gas containing hydrogen and carbon monoxide, a liquid fuel production device 4 that produces liquid fuel using the synthesis gas supplied from the gasification device 3 and the hydrogen produced by an electrolysis device 60 as raw materials, a power generation facility 5 that generates electricity using renewable energy, a hydrogen generation and supply device 6 that generates hydrogen and oxygen from water using the electricity generated in the power generation facility 5 and supplies the produced hydrogen and oxygen to the gasification device 3, and a control device 7 that controls the gasification device 3, the power generation facility 5, and the hydrogen generation and supply device 6, and liquid fuel is produced from the biomass feedstock using these components.

[0013] The biomass raw material supply device 2 performs predetermined pre-processing on biomass raw materials such as rice grains, bagasse, and wood, and supplies the pre-processed biomass raw materials to the gasification furnace 30 of the gasification device 3 via the raw material supply path 20. Here, the pre-processing of the biomass raw materials includes, for example, a drying process for drying the raw materials and a crushing process for crushing the raw materials.

[0014] The gasification apparatus 3 includes a gasification furnace 30 that gasifies the biomass raw material supplied via the raw material supply path 20, a gasification furnace sensor group 31 consisting of a plurality of sensors that detect the internal condition of the gasification furnace 30, a water supply device 32 that supplies water into the gasification furnace 30, an oxygen supply device 33 that supplies oxygen or air into the gasification furnace 30, a heating device 34 that heats the gasification furnace 30, a scrubber 35 that cleans the synthesis gas discharged from the gasification furnace 30, and a desulfurization device 36 that removes sulfur components from the synthesis gas cleaned by the scrubber 35 and supplies the cleaned synthesis gas to the liquid fuel production apparatus 4.

[0015] The water supply device 32 supplies water stored in a water tank (not shown) into the gasifier 30. The oxygen supply device 33 supplies oxygen stored in an oxygen tank (not shown) into the gasifier 30. The heating device 34 heats the gasifier 30 by consuming fuel supplied from a fuel tank (not shown) and electricity supplied from a power source (not shown). The amount of water supplied from the water supply device 32 to the gasifier 30, the amount of oxygen supplied from the oxygen supply device 33 to the gasifier 30, and the amount of heat input from the heating device 34 to the gasifier 30 are controlled by the control device 7. Note that in the fuel production system 1, there are cases where it is not necessary to actively supply water from the water supply device 32 to the gasifier 30 by supplying hydrogen from the hydrogen generation and supply device 6 (described below) into the gasifier 30 or into the raw material supply path 20. In this case, the water supply device 32 can be omitted from the fuel production system 1.

[0016] When water, oxygen, heat, etc. are fed into the gasification furnace 30, which has been charged with biomass raw material, using the water supply device 32, oxygen supply device 33, and heating device 34 described above, a total of 10 types of gasification reactions and their reverse reactions, such as those shown in the following formulas (1-1) to (1-5), proceed within the gasification furnace 30, and synthesis gas containing hydrogen and carbon monoxide is produced.

[0017] [ka]

[0018] The gasification furnace sensor group 31 is composed of, for example, a pressure sensor that detects the pressure inside the gasification furnace 30, a temperature sensor that detects the temperature inside the gasification furnace 30, an H2 / CO sensor that detects the H2 / CO ratio corresponding to the ratio of hydrogen to carbon monoxide in the synthesis gas inside the gasification furnace 30, and a CO2 sensor that detects carbon dioxide inside the gasification furnace 30. Detection signals from these sensors that make up the gasification furnace sensor group 31 are sent to the control device 7.

[0019] The gasification device 3 mixes the synthesis gas generated by the gasification reactions shown in the above formulas (1-1) to (1-5) and the reverse reaction thereof with hydrogen supplied from a hydrogen generation and supply device 6 described below, thereby adjusting the H2 / CO ratio of the synthesis gas to a predetermined target ratio corresponding to the liquid fuel to be produced (for example, when producing methanol, the target H2 / CO ratio is 2), and then supplies this synthesis gas to the liquid fuel production device 4.

[0020] The liquid fuel production device 4 is equipped with a methanol synthesis device, an MTG (Methanol To Gasoline) synthesis device, an FT (Fischer Tropsch) synthesis device, an upgrading device, etc., and by using these, liquid fuels such as methanol and gasoline are produced from synthesis gas adjusted to a predetermined H2 / CO ratio in the gasification device 3.

[0021] The power generation facility 5 is composed of a wind power generation facility that generates electricity using wind power, which is a renewable energy, a solar power generation facility that generates electricity using sunlight, which is also a renewable energy, etc. The power generation facility 5 is connected to a hydrogen generation and supply device 6, and electricity generated using renewable energy in the wind power generation facility, solar power generation facility, etc. can be supplied to the hydrogen generation and supply device 6. The power generation facility 5 is also connected to a commercial power grid 8. As a result, some or all of the electricity generated in the power generation facility 5 can be supplied to the commercial power grid 8 and can also be sold to an electric power company.

[0022] The hydrogen generation and supply device 6 includes an electrolysis device 60, a hydrogen filling pump 61, a hydrogen tank 62, a pressure sensor 63, and a hydrogen supply pump 64, and uses these to generate hydrogen using electricity supplied from the power generation equipment 5, and supplies the generated hydrogen to the gasification device 3.

[0023] The electrolysis device 60 is connected to the power generation facility 5, and generates hydrogen and oxygen from water by electrolysis using power supplied from the power generation facility 5. The electrolysis device 60 is also connected to the commercial power grid 8. This allows the electrolysis device 60 to generate hydrogen and oxygen not only using power supplied from the power generation facility 5, but also using power supplied from the commercial power grid 8 by purchasing power from an electric power company. The amounts of hydrogen and oxygen generated by the electrolysis device 60 are controlled by the control device 7.

[0024] The hydrogen filling pump 61 compresses the hydrogen produced by the electrolysis device 60 and fills it into the hydrogen tank 62. The amount of hydrogen filled by the hydrogen filling pump 61 is controlled by the control device 7. The hydrogen tank 62 stores the hydrogen compressed by the hydrogen filling pump 61. The pressure sensor 63 detects the internal tank pressure of the hydrogen tank 62 and sends a detection signal to the control device 7. The remaining amount of hydrogen in the hydrogen tank 62 is calculated by the control device 7 based on the detection signal of the pressure sensor 63. Therefore, in this embodiment, the hydrogen remaining amount acquisition means for acquiring the remaining amount of hydrogen in the hydrogen tank 62 is made up of the pressure sensor 63 and the control device 7.

[0025] The hydrogen supply pump 64 supplies hydrogen stored in the hydrogen tank 62 into the gasification furnace 30 of the gasification apparatus 3. The amount of hydrogen supplied from the hydrogen supply pump 64 into the gasification furnace 30 is controlled by the control device 7. Note that, although Fig. 1 illustrates a case in which hydrogen stored in the hydrogen tank 62 is supplied into the gasification furnace 30 by the hydrogen supply pump 64, the present invention is not limited to this. The hydrogen stored in the hydrogen tank 62 may be supplied upstream of the gasification furnace 30, more specifically, into the raw material supply path 20 for the biomass raw material.

[0026] The control device 7 is a computer that controls the amount of water supplied by the water supply device 32, the amount of oxygen supplied by the oxygen supply device 33, the amount of heat input by the heating device 34, the amount of hydrogen produced by the electrolysis device 60, the amount of hydrogen filled by the hydrogen filling pump 61, and the amount of hydrogen supplied by the hydrogen supply pump 64, based on detection signals from the gasification furnace sensor group 31 and detection signals from the pressure sensor 63 of the hydrogen tank 62, etc.

[0027] [Liquid fuel manufacturing method] A liquid fuel production method according to one embodiment of the present invention is a liquid fuel production method for producing liquid fuel from biomass feedstock, and includes: a gasification process for producing synthesis gas from the biomass feedstock; an electrolysis process for producing hydrogen from water using electricity generated using renewable energy; a liquid fuel production process for producing liquid fuel using the synthesis gas produced in the gasification process and the hydrogen produced in the electrolysis process as feedstocks; and a control process for controlling the gasification process and the electrolysis process, wherein the mass of the biomass feedstock (B), the mass of water vapor (S), and the mass of hydrogen (H) introduced into the liquid fuel production process satisfy the following formulas (1) to (4): H / B≦-0.031×S / B+0.079 (1) H / B≧-0.028×S / B+0.056 (2) S / B≧0.5 (3) H / B>0 (4)

[0028] In the above formulas (1) to (4), H / B is the ratio of the mass of hydrogen (H) to the mass of biomass material (B), and S / B is the ratio of the mass of steam (S) to the mass of biomass material (B).

[0029] In the method of producing liquid fuel using biomass gasification technology (Biomass to Liquid: BtL), biomass material is thermally decomposed and converted into gas, and then the hydrogen (H2) and carbon monoxide (CO) contained in the gas are used to produce liquid fuel. In the production of liquid fuel by BtL, one of the reactions shown in the following equations (5) to (7) is used. As can be seen from equations (5) to (7) below, the desired reaction will not occur unless the H2 / CO ratio is 2.

[0030] nCO+2(n+1)H2→C n H 2n+2 +nH2O (5) nCO+2nH2→C n H 2n +nH2O (6) CO+2H2→CH3OH (7)

[0031] As a result of experimental confirmation by the present inventors, it has been found that, as shown in FIG. 2, when the H2 / CO ratio is 2.0 or more and 2.5 or less, the amount of liquid fuel produced is maximized.

[0032] Therefore, the present inventors conducted an experiment to investigate the H2 / CO ratio when S / B and H / B were varied, and obtained the results shown in FIG. In Figure 3, the amount of carbon monoxide increased when hydrogen was supplied under all conditions. In Figure 3, the region above the bold line in the graph is the region where the amount of carbon monoxide increases and the H2 / CO ratio becomes 2 or more.

[0033] Based on FIG. 3, the graph shown in FIG. 4 was created with H / B on the vertical axis and S / B on the horizontal axis. From the results shown in Figure 4, the ratio of hydrogen to steam was set to achieve ideal gasification based on the experimental results. The linear equation for an H2 / CO ratio of 2.0 is H / B = -0.028 × S / B + 0.056. The linear equation for an H2 / CO ratio of 2.5 is H / B = -0.031 × S / B + 0.079. Therefore, in order to maintain the H2 / CO ratio at or above 2.0 and below 2.5, the above formulas (1) and (2) must be satisfied. That is, when H / B exceeds -0.031 × S / B + 0.079, the H2 / CO ratio exceeds 2.5, resulting in a decrease in the amount of liquid fuel produced. When H / B is less than -0.028 × S / B + 0.056, the H2 / CO ratio is less than 2.0, resulting in a decrease in the amount of liquid fuel produced.

[0034] By satisfying the above formula (3), the biomass raw material can be thermally decomposed and gasified.

[0035] By satisfying the above formula (4), liquid fuel can be produced.

[0036] According to the liquid fuel production method of this embodiment, the amount of carbon monoxide is increased by supplying hydrogen, and the supply ratio of hydrogen to water vapor can be specified so that the H2 / CO ratio after gasification is 2 or more.

[0037] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as set forth in the claims. [Explanation of symbols]

[0038] 1. Fuel production system 2. Biomass raw material supply device 20 Raw material supply route 3 Gasifier 30 Gasifier 31 Gasifier sensors 32 Water supply equipment 33 Oxygen supply device 34 Heating device 35 Scrubba 36 Desulfurization equipment 4 Liquid fuel production equipment 5. Power generation facilities 6. Hydrogen generation and supply device 60 Electrolyzer 61 Hydrogen filling pump 62 Hydrogen Tank 63 Pressure Sensor 64 Hydrogen supply pump 65 Carbon dioxide capture equipment 66 Carbon Dioxide Tank 67 Carbon Dioxide Conversion Device 68 Fuel synthesis device 7 Control Device

Claims

[Claim 1] A method for producing liquid fuel from a biomass feedstock, a gasification step for producing synthesis gas from biomass feedstock; an electrolysis process that produces hydrogen from water using electricity generated using renewable energy; a liquid fuel production process in which liquid fuel is produced using the synthesis gas produced in the gasification process and the hydrogen produced in the electrolysis process as raw materials; a control step for controlling the gasification step and the electrolysis step, The method for producing a liquid fuel, wherein the mass of the biomass material (B), the mass of the steam (S), and the mass of the hydrogen (H) introduced into the liquid fuel production step satisfy the following formulas (1) to (4): H / B≦-0.031×S / B+0.079 (1) H / B≧-0.028×S / B+0.056 (2) S / B≧0.5 (3) H / B>0 (4)

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