Process and device for preparing hydrogen from hydrogen iodide in iodine-sulfur circulation

Abstract

The invention belongs to the related technical field of hydrogen preparation through thermochemical circulation, and provides a process and a device for preparing hydrogen from hydrogen iodide in iodine-sulfur circulation. The device comprises an HIX steam stripping section, a reaction rectifying section, a reaction gas washing section and a steam stripping gas washing process and device. A shell pass and a tube pass of a novel shell-and-tube heat integration composite tower are filled with a 1# filler and a 2# filler respectively, N tower sections of a composite section are coaxially and hermetically connected, and the HIX steam stripping section, the reaction rectifying section and a water washing section are coupled together, so that gradient utilization of energy is realized; the system mixed gas containing O2 and SO2 is used as the circulating stripping gas of the stripping section of the composite tower, so that the generation of S, H2S and a small amount of H2SO4 mingled in an HIX system is inhibited, and the recovery rate of SO2 in HIX is improved; and the tower bottom material liquid of the reaction section of the heat integration composite tower and the acidic water of the washing section and the stripping gas washing tower are returned to the front mixing tank of the Bensen reactor, so that the quality utilization rate of the system is improved.

Description

technical field [0001] The invention relates to a process and a device for preparing hydrogen from hydrogen iodide in an iodine-sulfur cycle, and belongs to the related technical field of thermochemical cycle preparation of hydrogen. Background technique [0002] The main energy supply in the world today comes from fossil fuels. However, fossil fuels are non-renewable and pollute the environment, which does not meet the requirements of carbon neutrality. There are solutions to reduce the environmental impact of fossil fuels, such as carbon capture, storage, and thermal decarbonization. However, while carbon capture can save environmental costs, it cannot be a long-term solution for energy sustainability. Due to the high energy density, cleanness and non-toxicity of hydrogen energy, the formation of more compounds and large reserves, hydrogen energy is considered to be an alternative energy carrier in the future. However, there are many disadvantages in the traditional hydr...

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Problems solved by technology

However, there are many disadvantages in the traditional hydrogen production method: fossil fuel dry gas hydrogen production process CO 2 There are many emissions, the prepared hydrogen contains sulfur, and high-purity hydrogen needs to be desulfurized and purified; the electrolytic hydrogen production process has low efficiency and high cost; the hydrogen obtained by biomass decomposition hydrogen production is limited and cannot be used in large-scale industries, etc.

The process of producing hydrogen from hydrogen iodide in the traditional iodine-sulfur cycle is complex, and the HIX decomposition process mainly includes phosphoric acid extraction, electrochemical decomposition and high-pressure reactive distillation

The process of the phosphoric acid extraction unit is complicated, and the introduction of impurities will affect the circulation and separation of the system; the electrochemical decomposition consumes a lot of energy, the hydrogen production efficiency is low, and it cannot be applied industrially. It is currently in the laboratory research stage; high-pressure reactive distillation, temperature High energy consumption, using traditional distillation equipment to process HIX stripping process, HIX reactive distillation process, HIX water washing process requires 3 rectification towers, and the stripping tower needs to consume energy, and the high temperature of the HIX reactive distillation tower and steam The coupling of the column is difficult, and the structure of the ordinary distillation column cannot be solved, and the cascade utilization of energy cannot be realized

The HIX stripping section of the traditional process does not involve the HIX stripping section directly into the HIX high-pressure reactive distillation process, and a small amount of SO in the gas phase 2 Bringing it into the HIX reaction distillation section will affect the energy consumption and safety performance of the HIX reaction system. If an inert gas is used for stripping, it will cause side reactions, which will increase the system cost and separation difficulty, and reduce the hydrogen production efficiency.

The recovery of acidic water in the traditional HIX decomposition hydrogen production process is insufficient, resulting in system I 2 and SO 2 Consumption, hydrogen production costs increase

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