【Ten Years of Rapid Development in Chemical Equipment】1749–2015: The World’s First Unit for the Purification of Waste Sulfuric Acid Produced by the High-Temperature Pyrolysis of Calcium Carbide to Produce Acetylene

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Happy May Day 2024! Safety first. Let’s give praise and support to the achievements made in China’s chemical technology and equipment sector. **********************【Ten Years of Progress in Chemical Equipment】A continuously updated summary post is available; feel free to join the discussions at https://bbs.hcbbs.com/thread-3576046-1-1.html (Source: Haichuan Chemical Forum Website) ***************** To address the environmental issues posed by waste sulfuric acid generated during production, Beiyuan Chemical Company has established a project for the cracking and recycling of 30,000 tons of waste sulfuric acid per year, thereby enabling the reuse of this waste and putting into practice the environmental concept of \"low-carbon production and efficient utilization\". Upon completion, the project will be the world’s first facility for the purification of waste sulfuric acid produced by the high-temperature pyrolysis calcium carbide method for acetylene production. 　　 The project involves a cracking unit with a production capacity of 30 kt/a of waste sulfuric acid (75%), utilizing the MECS process package from the United States. Natural gas is used as fuel, along with sulfur, to crack acetylene and purify the waste sulfuric acid. The facility is designed to produce 20,000 tons per year of 98% sulfuric acid, while the excess SO2 is used to manufacture 10,000 tons per year of Na2SO3. The process technology comprises five steps: cracking, purification, drying, conversion, and absorption of waste sulfuric acid. Specifically, the waste sulfuric acid is sprayed into the cracking furnace in a mechanically atomized form, where it undergoes cracking due to the high temperatures generated by the combustion of organic substances present in natural gas, sulfur, and the waste sulfuric acid itself. The gases emerging from the cracking furnace are cooled, washed, and demisted, after which they are dehydrated using 93% sulfuric acid. Subsequently, a vanadium catalyst is used to convert SO2 into SO3, and 98% sulfuric acid is then used to absorb the SO3 produced, resulting in sulfuric acid with a concentration of 98.5% that can be reused in chemical manufacturing, thereby enabling the recycling of waste sulfuric acid. This technical equipment is at the international forefront, with all its parameters exceeding **environmental protection requirements. 　　 Since the project commenced in September 2014, Beiyuan Chemical Company has overcome various difficulties such as tight deadlines, heavy workload, and climate impacts to ensure timely completion and high construction quality. To date, the civil works for the spent sulfuric acid cracking project have been successfully completed and installed, and the installation team has begun working on the prefabrication of non-standard equipment and steel structures within the plant area, indicating that another significant step has been taken toward the project’s timely commissioning. 　　 It is reported that the project covers an area of about 15 mu, with a total investment of 125.16 million yuan, and is set to be completed and put into operation by the end of this year. Once completed, the project will save over 30 million yuan annually in costs related to the purchase of sulfuric acid and the treatment of waste sulfuric acid. It will also completely resolve the environmental issues caused by waste sulfuric acid, thereby improving the company’s economic and environmental performance.