【Ten Years of Great Progress in Chemical Technology】Development of Wet Oxidation Technology for Sulfur-Containing Waste Alkali Liquids Associated with Ethylene Production from 1.26 to 2022
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Ten years of rapid development in chemical technology – praise for China’s prosperity and strength. This is just a starting point; more participation from everyone will make things even more lively. HaiChuan becomes even better with your involvement; we welcome everyone to join in the forum discussions. Be careful with fire risks as the heat increases in July. On December 19, 2022, Sinopec’s “Ten Dragon” technology development project, namely “Development and industrial testing of wet oxidation technology for sulfur-containing waste alkali solutions associated with million-ton ethylene production,” successfully completed all its objectives and came to a successful conclusion. This project was developed jointly by Sinopec Zhenhai Refining & Chemical Co., Ltd., Sinopec (Dalian) Research Institute of Petrochemicals Co., Ltd., Sinopec Engineering Construction Company, East China University of Science and Technology, Ningbo New Materials Research Institute and other organizations. Its aim is to overcome foreign technological bottlenecks and address the problem of treating sulfur-containing waste alkali solutions in the process of expanding ethylene production facilities in China. The process package was approved by the company’s Technology Department in July 2020, and the project commenced operations in December 2020. In December 2021, the plant underwent a successful trial run, with a sulfide removal rate of over 99.99% and a COD removal rate that was nearly 3 percentage points higher than that of similar foreign technologies. This marked the first industrial application of large-scale wet oxidation treatment technology, with 100% localization of the equipment, instruments, and software used. From July to August 2022, industrial unit calibration was carried out. The calibration results show that, after oxidation, indicators such as the sulfide concentration in the waste alkaline solution, COD concentration, oxygen content in the exhaust gas, and the operating cost of the facility are all better than the targets set in the research design. Compared with internationally leading similar technologies, this device requires less investment, has lower operating costs, a longer service life, higher processing efficiency and automation levels, resulting in significant economic and social benefits.
In December 2022, the project passed the acceptance review by Sinopec’s Science and Technology Department. Through three years of intensive research, this project exceeded all the set targets; a total of 34 Chinese invention patents were applied for, of which 11 were granted, and 6 innovative achievements were obtained: a complete set of technologies for the wet oxidation of sulfur-containing waste alkali solutions associated with ethylene production on a scale of 1 million tons per year (with a treatment capacity of 19.2 t/h) was developed, enabling efficient, low-energy-consuming, and long-term stable operation of industrial plants. A circulating internal-loop reactor suitable for the wet oxidation of large-scale waste alkaline solutions was developed, and the reactor structure and material flow patterns under optimal operating conditions were determined to ensure the proper treatment of the waste alkaline solutions. A fractal distributor to enhance gas-liquid mass transfer was developed, utilizing bubbles of different dimensions to simultaneously improve the mass transfer efficiency and gas holdup within the reactor. An efficient, scale-resistant integrated energy utilization system has been developed to recover reaction heat while ensuring the stable operation of the equipment. A clog-resistant coupling process of inertial guidance pre-separation and micro-vortex fine separation was developed to achieve efficient separation under conditions of fluctuating gas flow, without any issues of scaling or blockage. An automatic control system for the device was developed to achieve full-automatic control throughout its operation process. Innovative control technologies such as \"no backflow during discharge from the liquid separation tank\" and \"online switching of high-pressure feed pumps\" were introduced, thereby reducing labor costs.