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Graphite heat exchangers are primarily used in the chlor-alkali industry for key processes such as hydrochloric acid concentration, hydrogen chloride gas recovery and synthesis, as well as waste heat recovery. Thanks to their excellent resistance to strong acid corrosion and high heat transfer efficiency, they have become essential core equipment in this field. During the chlor-alkali production process, large amounts of dilute hydrochloric acid are produced as a by-product, and its concentration needs to be increased through evaporation and concentration or hydrogen chloride desorption processes. Traditional metal heat exchangers are highly susceptible to corrosion and failure in high-temperature hydrochloric acid steam environments, whereas graphite heat exchangers can withstand hydrochloric acid solutions and hydrogen chloride gas at temperatures above 80°C, ensuring the long-term operation of the system. When used in conjunction with a multi-effect evaporation (MVP) system, graphite equipment undertakes the task of heat exchange between different effect stages, enabling a reduction in steam consumption per unit of production by 30% to 50%, thereby significantly improving energy efficiency. In addition, graphite heat exchangers are also widely used in the following applications: the cooling systems of hydrogen chloride synthesis furnaces, where an immersion or spray design is employed to cool the graphite furnace body through water jackets, ensuring that the heat generated by the reaction is removed promptly. Residual heat recovery from electrolyzers: It can withstand the highly alkaline environment of high-concentration sodium hydroxide solutions, enabling the recovery and utilization of heat during the electrolysis process. Treatment of wastewater containing organic solvents: Prevents the precipitation of metal ions from contaminating the solution or intermediates, thereby ensuring product purity; it is particularly suitable for the production of pharmaceutical-grade chemicals. The main types of heat exchanger structures include shell-and-tube, plate, and block-and-hole types. Among them, plate heat exchangers have a heat transfer efficiency 3–5 times higher than that of tube heat exchangers, with a heat recovery rate exceeding 90%, making them more suitable for applications with high energy-saving requirements. Although graphite materials have a low tensile strength and are only suitable for low-pressure environments (usually ≤0.5 MPa), their density and corrosion resistance can be significantly improved through treatments such as impregnation with phenolic resin or polytetrafluoroethylene.