Method for producing methanol

Abstract

The present invention relates to a method for producing methanol, comprising the following steps. (a) A step of producing hydrogen supply raw materials by electrolysis; (b) A step of providing carbon oxide raw materials during the electrolysis operation period of step (a); (c) A step of obtaining methanol synthesis gas by mixing at least a portion of the hydrogen feed and a carbon oxide source consisting of carbon monoxide and / or carbon dioxide feed; (d) A step of adjusting the molar content of hydrogen, carbon monoxide and / or carbon dioxide from step (c) so that the module M((H2-CO2) / (CO2+CO)) is between 1.9 and 2.2; (e) A step of converting methanol synthesis gas to methanol in one or more boiling water reactors during a period when the electrolysis of step (a) is not being operated; (f) Interrupting the conversion of methanol synthesis gas in one or more boiling water reactors by heat exchange with boiling water; Here, in step (f), one or more boiling water reactors are heated by one or more auxiliary heaters to maintain the boiling of the water in one or more boiling water reactors.

Description

【Technical Field】 【0001】 Methanol is an important chemical feedstock used in various industries, including plastics, adhesives, and solvents. Typically, the methanol reaction involves the catalytic conversion of carbon oxides and hydrogen gas. In the present invention, the methanol reaction is carried out in a so-called boiling water type reactor. 【Background Art】 【0002】 The design of a boiling water type reactor for methanol synthesis consists of a reaction vessel containing a plurality of tubes filled with an effective catalyst for the exothermic methanol synthesis reaction. Catalyst tubes are installed inside the reaction vessel. The catalyst is usually composed of copper and zinc oxide, which are known as effective catalysts for the methanol synthesis reaction. 【0003】 The reaction vessel is equipped with a cooling system for cooling the catalyst layer. This cooling system is designed to maintain the temperature of the catalyst layer within a predetermined range for the methanol synthesis reaction. A water-cooled system using boiling water is preferred for the cooling system. The cooling system is a water-cooled system that circulates water inside the reaction vessel to remove excess heat. 【0004】 During operation, the reactants, carbon oxides and hydrogen gas, are introduced into the reaction vessel at a controlled rate. The reactants pass through the catalyst bed, where they are partially converted to methanol. The remaining portion forms a methanol synthesis loop and is recycled (re-circulated, reused) to the reactor. 【0005】 The design of a boiling water type reactor for methanol synthesis offers several advantages compared to conventional methanol production methods. 【0006】 The main advantage of using a boiling water type reactor is that the reaction can proceed more effectively by efficiently removing the reaction energy and maintaining the temperature close to an equilibrium state. 【0007】 The production of green methanol, which is methanol produced using renewable carbon sources and hydrogen generated by electrolysis from renewable energy sources such as wind, solar, and hydropower, faces several challenges that must be overcome to achieve large-scale production and widespread adoption. 【0008】 Under normal operation, a boiling water reactor provides the cooling necessary for the exothermic reaction of methanol synthesis. However, if the supply of hydrogen is insufficient due to the instability of renewable electricity, the methanol yield may decrease. In some cases, the process may even come to a complete halt until renewable electricity becomes available again. If the generation of reaction heat stops within the boiling water reactor, methanol synthesis will eventually come to a complete halt, and the reactor temperature will gradually decrease due to heat loss. 【0009】 The methanol reactor can maintain a high temperature during hot standby using a starting steam ejector with an auxiliary steam supply. The steam ejector is used to heat the methanol reactor during startup from a cold state, and a similar system can be applied to maintaining the high temperature. However, if the starting steam system needs to be running continuously, or if such a system does not exist, an electric heater can be used as the starting heater. 【0010】 To prevent such disruptions from affecting the methanol synthesis process, it is necessary to maintain the reactor coolant temperature at a constant level. This can be achieved by providing auxiliary heating to the reactor coolant in addition to the heat supplied from the boiling water reactor. The auxiliary heating helps maintain the reactor coolant temperature at a safe level, ensuring the efficient and continuous operation of the methanol synthesis process. 【0011】 There are two main reasons for maintaining pressure / temperature on the shell side when a boiling water reactor is in standby mode: - When methanol catalysts are exposed to low temperatures, there is a risk that wax will condense inside the catalyst, leading to catalyst deactivation. - When the reactor is cooled and then reheated during restart, frequent use of this procedure poses a risk of fatigue stress. Maintaining a constant boiling water pressure during standby mode minimizes reactor temperature fluctuations, eliminating the need to consider fatigue stress in the mechanical design. [Overview of the Initiative] [Problems that the invention aims to solve] 【0012】 Therefore, there is a need for a reliable and effective auxiliary heating device that can be used in the event of a failure in the methanol synthesis process, thereby ensuring the efficient and continuous operation of the process. The present invention aims to provide such a system, as will be described in detail below. [Means for solving the problem] 【0013】 The present invention provides a method for producing methanol, comprising the following steps: (a) A step of producing hydrogen supply raw materials by electrolysis; (b) A step of providing carbon oxide feedstock during the electrolysis operation period of step (a); (c) A step of obtaining methanol synthesis gas by mixing at least a portion of a hydrogen feed and a carbon oxide source consisting of at least a portion of a carbon monoxide and / or carbon dioxide feed; (d) A step of adjusting the molar content of hydrogen, carbon monoxide and / or carbon dioxide from step (c) so that the module M((H2-CO2) / (CO2+CO)) is between 1.9 and 2.2; (e) A step of converting methanol synthesis gas to methanol in one or more boiling water reactors during a period when the electrolysis of step (a) is not being operated; (f) Interrupting the conversion of methanol synthesis gas in one or more boiling water reactors by heat exchange with boiling water; Here, in step (f), one or more boiling water reactors are heated by one or more auxiliary heaters to maintain the boiling of the water in one or more boiling water reactors. 【0014】 In embodiments of the present invention, one or more boiling water reactors are heated by a common auxiliary heater in step (f). 【0015】 In one embodiment, one or more auxiliary heaters are electric heaters. These electric heaters are preferably positioned as part of a riser / downcomer system to one or more boiling water reactors. 【0016】 The riser / downcomer is a pipe or channel that extends along the core of the reactor. The primary function of the riser / downcomer is to supply cooling water from the top to the bottom of the reactor vessel by natural circulation, where it enters the core. 【0017】 In one embodiment, a common electric heater is positioned as part of the steam drum of the methanol reactor and supplies heat that is circulated through the boiling water reactor by a circulation pump. 【0018】 In one embodiment, the heat input of the electric heater is controlled by adjusting the power input to maintain the water-side pressure of the boiling water reactor. 【0019】 In one embodiment, the electric heater is used for heating during startup of the boiling water reactor. 【0020】 An advantage of this embodiment is that it eliminates the need for an ejector, which is typically used when starting up a conventional boiling water reactor. 【0021】 In one embodiment, the electrolysis is powered by renewable energy. 【0022】 In one embodiment, the electrolysis is carried out using a solid oxide electrolysis apparatus. 【0023】 In one embodiment, the carbon dioxide source is pure CO2 with a concentration > 95%, more preferably > 99%. 【0024】 In one embodiment, the carbon dioxide is of biological and / or anthropogenic origin. Carbon dioxide of biological origin refers to carbon dioxide (CO2) released into the atmosphere by natural biological processes or the combustion of biomass (such as wood and agricultural residues). 【0025】 Anthropogenic carbon dioxide emissions refer to carbon dioxide (CO2) released into the atmosphere as a result of human activities. These emissions are mainly due to the combustion of fossil fuels (such as coal, oil, and natural gas) in energy production, transportation, and industrial processes. 【0026】 In one embodiment, CO2 is partially converted to CO by electrolysis or another electrolytic process. 【0027】 In one embodiment, at least a portion of the methanol is further converted to gasoline or jet fuel.

Claims

[Claim 1] (a) A step of producing hydrogen supply raw materials by electrolysis; (b) Providing carbon oxide feedstock during the electrolysis operation period of step (a); (c) A step of obtaining methanol synthesis gas by mixing at least a portion of the hydrogen feed and a carbon oxide source consisting of carbon monoxide and / or carbon dioxide feed; (d) A step of adjusting the molar content of hydrogen, carbon monoxide and / or carbon dioxide from step (c) so that the module M((H2-CO2) / (CO2+CO)) is between 1.9 and 2.2; (e) During the period when the electrolysis of step (a) is not in operation, the step of converting methanol synthesis gas to methanol in one or more boiling water reactors; (f) Interrupting the carbon oxide feed in step (b) and stopping methanol production in one or more methanol reactors; A method for producing methanol, including The method wherein, in step (f), one or more boiling water reactors are heated by one or more auxiliary heaters to maintain the boiling of water in one or more boiling water reactors. [Claim 2] The method according to claim 1, wherein in step (f), one or more boiling water reactors are heated by a common auxiliary heater. [Claim 3] The method according to claim 1 or 2, wherein one or more of the auxiliary heaters are electric heaters. [Claim 4] The method according to claim 3, wherein one or more electric heaters are located within the riser / downcomer system of one or more boiling water reactors. [Claim 5] The method according to claim 3, wherein a common electric heater is located as part of the steam drum of the methanol reactor, and heat is circulated through the boiling water reactor by a circulation pump. [Claim 6] The method according to claim 3 or 4, wherein the heat input of the electric heater is controlled by adjusting the power input to maintain the water-side pressure of the boiling water reactor. [Claim 7] The method according to any one of claims 1 to 6, wherein the electric heater is used to heat the boiling water reactor during startup. [Claim 8] The method according to any one of claims 1 to 7, wherein the electrolysis is operated using renewable energy. [Claim 9] The method according to any one of claims 1 to 8, wherein the electrolysis is carried out in a solid oxide electrolysis apparatus. [Claim 10] The method according to any one of claims 1 to 9, wherein the carbon oxide source is pure CO2 with a concentration of >95%, more preferably >99%. [Claim 11] The method according to any one of claims 1 to 10, wherein the carbon dioxide is of biological and / or anthropogenic origin. [Claim 12] The method according to any one of claims 1 to 11, wherein CO2 is partially converted to CO by electrolysis or in another electrolytic apparatus. [Claim 13] The method according to any one of claims 1 to 12, wherein at least a portion of the methanol is further converted into gasoline or jet fuel.

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