KR-102962493-B1 - MULTI-STAGE REACTOR FOR REVERSE WATER GAS SHIFT REACTION AND METHOD FOR PRODUCING SYNTHESIS GAS USING THE SAME

KR102962493B1KR 102962493 B1KR102962493 B1KR 102962493B1KR-102962493-B1

Abstract

One embodiment of the present invention provides a multistage reactor for reverse water gas reaction (RWGS), comprising: a first stage reactor that receives hydrogen and carbon dioxide to produce carbon monoxide and water by reverse water gas reaction and discharges the produced carbon monoxide and water and residual gas; a first heat exchanger located downstream of the first stage reactor and receives the carbon monoxide, water and residual gas discharged from the first stage reactor to condense; and a second stage reactor located downstream of the first heat exchanger and receives the residual gas from which the condensate has been removed after condensation to produce carbon monoxide and water by reverse water gas reaction and discharges the produced carbon monoxide and water and residual gas.

Inventors

정운호
구기영
박용하

Assignees

한국에너지기술연구원

Dates

Publication Date: 20260513
Application Date: 20231113

Claims (12)

As a multistage reactor for reverse water-gas reaction (RWGS), A first-stage reactor that receives hydrogen and carbon dioxide to produce carbon monoxide and water through a reverse water-gas reaction, and discharges the produced carbon monoxide, water, and residual gas; A first heat exchanger located downstream of the first stage reactor and receiving and cooling carbon monoxide, water, and residual gas discharged from the first stage reactor, and A first gas-water separator that separates and removes condensate from carbon monoxide, water, and residual gas cooled while passing through the first heat exchanger, and A second-stage reactor that receives residual gas from which condensate has been removed by the first gas-water separator, generates carbon monoxide and water by a reverse water-gas reaction, and discharges the generated carbon monoxide, water, and residual gas; A second heat exchanger that receives and cools carbon monoxide, water, and residual gas discharged from the above second-stage reactor, and It includes a second gas-water separator that separates and removes condensate from carbon monoxide, water, and residual gas that have been cooled by passing through the second heat exchanger, The first heat exchanger exchanges heat between the carbon monoxide, water, and residual gas discharged from the first stage reactor and the residual gas discharged from the first gas-water separator to reheat the residual gas discharged from the first gas-water separator and supply it to the second stage reactor. A multi-stage reactor for a reverse water-gas reaction, characterized in that the second heat exchanger exchanges heat between carbon monoxide, water, and residual gas discharged from the second stage reactor and residual gas discharged from the second gas-water separator to reheat residual gas discharged from the second gas-water separator.
In paragraph 1, A multi-stage reactor for a reverse water-gas reaction, further comprising a third stage reactor located downstream of the second heat exchanger, which receives residual gas from which condensate has been removed after condensation, generates carbon monoxide and water by a reverse water-gas reaction, and discharges the generated carbon monoxide and water and residual gas.
In paragraph 1, A multistage reactor for a reverse water-gas reaction, characterized by including a condenser located downstream of the first heat exchanger and condensing carbon monoxide, water, and residual gas discharged from the first heat exchanger.
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In paragraph 1, A multi-stage reactor for a reverse water-gas reaction, characterized by further including a preheater located downstream of the first heat exchanger and receiving the residual gas reheated from the first heat exchanger for additional heating.
In paragraph 6, The above second-stage reactor is, A multi-stage reactor for a reverse water-gas reaction, characterized by receiving residual gas further heated from the above preheater and generating carbon monoxide and water through a reverse water-gas reaction via an endothermic reaction.
In paragraph 1, The above-mentioned first-stage reactor or second-stage reactor is, A multi-stage reactor for a reverse water-gas reaction, characterized by being provided as an adiabatic reactor or equipped with an electric heater installed externally or internally, heating hydrogen and carbon dioxide to a temperature of 300 to 500°C to produce carbon monoxide and water by a reverse water-gas reaction.
A method for producing synthesis gas using a multistage reactor for reverse water gas reaction (RWGS), A first stage reactor that generates carbon monoxide and water through a reverse water-gas reaction using hydrogen and carbon dioxide supplied from the outside, and discharges the generated carbon monoxide and water and residual gas, and A step in which a first heat exchanger exchanges heat between the carbon monoxide, water, and residual gas discharged from the first stage reactor and the residual gas discharged from the first gas-water separator, thereby cooling the carbon monoxide, water, and residual gas discharged from the first stage reactor and reheating the residual gas discharged from the first gas-water separator and supplying it to the second stage reactor; The step of the above second-stage reactor receiving the reheated residual gas and generating carbon monoxide and water by a reverse water-gas reaction, and discharging the generated carbon monoxide and water and the residual gas, and A method for producing synthesis gas using a multistage reactor for a reverse water-gas reaction, comprising the step of a second heat exchanger exchanging heat between carbon monoxide, water, and residual gas discharged from the second stage reactor and residual gas discharged from the second gas-water separator, thereby cooling the carbon monoxide, water, and residual gas discharged from the second stage reactor and reheating the residual gas discharged from the second gas-water separator.
In Paragraph 9, A method for producing synthesis gas using a multistage reactor for a reverse water-gas reaction, further comprising the step of supplying residual gas from the second heat exchanger to a third stage reactor to produce carbon monoxide and water by a reverse water-gas reaction, and discharging the produced carbon monoxide and water and residual gas.
In Paragraph 9, A method for generating synthesis gas using a multistage reactor for a reverse water-gas reaction, characterized by further including the step of removing condensate generated as carbon monoxide, water, and residual gas are condensed from the first heat exchanger by the first gas-water separator.
In Paragraph 11, A method for producing synthesis gas using a multistage reactor for a reverse water-gas reaction, characterized by further including a step in which, after the carbon monoxide, water, and residual gas are condensed from the first heat exchanger, a condenser re-condenses the carbon monoxide, water, and residual gas.

Description

Multi-stage reactor for reverse water-gas shift reaction and method for producing synthesis gas using the same The present invention relates to a multistage reactor for a reverse water-gas reaction, and more specifically, to a multistage reactor for a reverse water-gas reaction that has an excellent carbon dioxide conversion rate while operating at a relatively low temperature. Globally, there is a continuing trend of developing and expanding the use of synthetic fuels (e-fuels) as a means of diversifying energy sources following the depletion of fossil fuels and reducing greenhouse gas emissions due to climate change. Meanwhile, as the need to reduce greenhouse gas emissions in the aviation sector to address climate change emerges, regulatory and response movements by the international community are becoming increasingly active. With the rapid increase in air traffic, interest in managing emissions and greenhouse gases around international aircraft and airports is growing. In particular, the global aviation industry accounts for 2% of worldwide carbon dioxide emissions, so measures to reduce greenhouse gas emissions are being considered. In the field of carbon dioxide reduction technology, the most important aspect is the technology for chemically converting generated carbon dioxide; a representative example is the catalytic process that converts carbon dioxide into methanol through a hydrogenation reaction. The conventional hydrogenation reaction of carbon dioxide is a one-step reaction that directly hydrogenates carbon dioxide, but it has the disadvantage of very low process efficiency due to the water produced when carbon dioxide undergoes hydrogenation. The reverse water-gas reaction was developed for the specific purpose of reducing carbon dioxide and utilizes a method in which hydrogen, a high-energy form, is added as a feedstock for the reaction. The reverse water-gas reaction is an endothermic reaction governed by thermodynamic equilibrium and must be operated at high temperatures of 600 to 800°C or higher to have sufficient reactivity. The synthesis of hydrocarbons by the conversion of carbon dioxide using hydrogen generally proceeds as a two-step continuous reaction. Specifically, the carbon dioxide conversion reaction consists of a first step in which carbon dioxide supplied as a reactant is converted into carbon monoxide via the Reverse Water Gas Shift (RWGS), and a second step in which the generated carbon monoxide combines with hydrogen via the Fischer-Tropsch (FTS) reaction to be converted into hydrocarbons (olefins, etc.). The first and second steps are carried out in separate reactors, and the water generated after the first step reaction is removed. The problem with this reverse water-gas reaction is that selective heating based on the location and section of the reactor is impossible, a temperature gradient occurs between the outside and inside of the reactor, and localized heating occurs, resulting in thermal cracking as a side effect. Since this side effect reduces the carbon monoxide yield and is a major cause of reduced process performance, controlling the heating conditions is a very important variable. In addition, since the downstream (second stage) reaction is operated at a relatively low temperature between 200 and 300°C, a temperature difference of 300 to 400°C occurs between the first and second stage reactions, and even if a high-efficiency heat exchanger is installed in this gap, there is an inevitable limit to the reduction in thermal efficiency. FIG. 1 is a conceptual diagram illustrating the concept of a multi-stage reactor for reverse water-gas reaction (RWGS) according to one embodiment of the present invention. FIG. 2 is a diagram illustrating the schematic configuration and operating principle of a multistage reactor according to one embodiment of the present invention. Figure 3 is a graph showing the carbon dioxide conversion rate according to the temperature of the endothermic reaction for each ratio of hydrogen to carbon dioxide in the RWGS reaction. Figure 4 is a graph showing the carbon dioxide conversion rate according to the ratio of hydrogen to carbon dioxide. FIG. 5 is a graph showing the results of the RWGS reaction performed stepwise in a multistage reactor according to the present invention. The present invention will be described below with reference to the attached drawings. However, the present invention may be implemented in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals. Throughout the specification, when it is stated that a part is "connected (connected, in contact, combined)" with another part, this includes not only cases where they are "directly connected," but also cases where they ar