The wastewater treatment system for China Anlian United Coal Chemical’s 1.7 million tons per year methanol and converted olefins production project has seen the completion of the entire process flow

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The wastewater treatment system for Zhong’an United Coal Chemical’s 1.7 million tons per year methanol and converted olefins production project has achieved full operational capability. Author/Source: Huahua Network – Coal Chemicals. Date: 2020-01-05. Clicks: 77. On December 20th and 25th, the high-salinity water evaporation and crystallization units in this wastewater treatment system were able to separate sodium sulfate and sodium chloride from the wastewater generated by the plant, marking the achievement of the goal of treating wastewater on a differentiated basis and enabling its resource utilization. The Zhong’an United Wastewater Treatment Plant is a supporting facility for coal chemical projects; construction began in May 2018, with a total investment of over 1 billion yuan. It consists of two sections: conventional wastewater treatment and high-salinity water treatment. The wastewater treatment plant is primarily used to treat saline wastewater, production wastewater, domestic wastewater, and cleaning wastewater generated by coal chemical plants, thereby meeting the environmental requirements stipulated in the project’s environmental impact assessment, which require that all wastewater be reused and not discharged outside. Industrial wastewater has a complex composition and low biodegradability, making its treatment quite challenging. Coal chemical industry wastewater, with its high levels of salts, hardness, fluoride, and silicon, poses an even greater technical challenge in terms of achieving full reuse of the wastewater; moreover, crystallizing the main salt components such as sodium sulfate and sodium chloride to meet the standards for industrial nitrate and salt products is also a worldwide challenge. To achieve the goal of \"zero discharge\" of wastewater, Sinopec Group has listed the Zhongan United wastewater \"zero discharge\" project as one of its key projects. A team composed of technical experts from design, research and development, and production units was formed to work on this technical challenge. Through the relentless efforts of these scientists and engineers, proprietary technologies for the \"zero discharge\" treatment of high-salinity wastewater were developed, and these technologies have been successfully applied in the wastewater treatment processes of Zhongan United’s coal chemical industry. The Zhongan United coal chemical plant generates wastewater, and after being treated by biochemical and reclaimed water treatment systems, most of this water is reused. The high-salinity water generated during the treatment process has a complex composition, high concentration, and significant fluctuations. After numerous investigations, analyses, and experiments by the technical team, a treatment process comprising pretreatment, membrane concentration, nanofiltration separation, and multi-effect evaporation crystallization was ultimately determined. The designed capacity for treating this high-salinity water is 360 m3/h; it is possible to reuse all the treated water, and industrial-grade sodium chloride and sodium sulfate products can be obtained for export, thereby achieving recycling of water resources and salt. The high-salinity water treatment unit at the Zhongan United Wastewater Treatment Plant is Sinopec’s first \"zero-discharge\" system capable of achieving the crystallization of salts. The implementation of a complete \"zero-discharge\" technology process for wastewater is of great significance for both Zhongan United and Sinopec. It not only helps these companies achieve sustainable development but also serves as a model for the application of wastewater treatment technologies in the coal chemical industry, making a positive contribution to advancing the clean and efficient use of coal in China on a global scale. The 1.7 million tons per year coal-to-methanol and converted olefins project of Zhongan United Coal Chemical Co., Ltd. is a large-scale coal chemical integration project established through a joint investment by Sinopec Great Wall Energy Chemical Company and Anhui Wanbei Coal and Electricity Group; it is one of the landmark projects in Sinopec’s coal chemical business. The approved total investment for the first phase of this project is 26.7 billion yuan, of which 20.2 billion yuan is allocated to coal chemical projects and 6.5 billion yuan to coal mining projects. The project will involve the construction of facilities for producing 1.7 million tons per year of methanol, as well as 350,000 tons per year of linear low-density polyethylene and 350,000 tons per year of polypropylene. It will also rely on 856 million tons of coal resources, of which 406 million tons are in exploitable reserves; in addition, a coal mine with an annual production capacity of 4 million tons will be built.