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Successful trial production of 90,000 tons of LNG at Ningxia Yufeng’s coke oven gas-based project Author/Source: Gasification World Date: April 20, 2023 Clicks: 47 On April 16, 2023, after more than 100 hours of intensive efforts, the LNG project of Ningxia Yufeng Chemical Co., Ltd. (referred to as “Ningxia Yufeng”) managed to produce LNG through its liquefaction system. Next, Ningxia Yufeng will continue to optimize the production processes, conduct 72-hour tests to ensure that the project meets performance standards, and make unremitting efforts to achieve operational capacity as soon as possible. The Xia Yufeng Chemical Circular Economy Project for producing 90,000 tons per year of LNG from coke oven gas is based on the existing production of ammonia from coke oven gas. Through technical upgrades, a facility is established that uses coke oven gas as the raw material (with natural gas serving as a supplementary feedstock when there is a shortage of coke oven gas, and it is introduced at the stage of precise desulfurization). The coke oven gas undergoes preprocessing, purification, shift reaction, decarburization, and deep cryogenic separation to isolate CH4 and CmHn from it, thereby creating a methane liquefaction unit with a nominal capacity of 90,000 tons per year; this results in an overall production capacity of 150,000 tons per year of ammonia along with 90,000 tons per year of LNG. In June 2022, the Industry and Information Technology Bureau of Zhongwei, Ningxia, announced that the energy-saving report for Ningxia Yufeng Chemical’s project to produce 90,000 tons per year of LNG using coke oven gas in a circular economy approach had been approved. In 2012, Ningxia Yufeng Chemical Co., Ltd. invested in building a synthetic ammonia plant with an annual production capacity of 150,000 tons, using the excess coke oven gas produced by Ningxia Yuguang Energy Industry Co., Ltd. located within the Ningxia Zhongwei Industrial Park. In order to make full use of the 1.2 million tons per year of by-product coke oven gas produced in the second phase of Ningxia Yuguang Energy Industry Co., Ltd., further expand production capacity, and adjust the product mix, in 2021 Ningxia Yufeng Chemical Co., Ltd. decided to build a liquefied methane plant with a nominal capacity of 90,000 tons per year, based on the existing ammonia synthesis facility. This plant will utilize coke oven gas as its raw material (with natural gas used as a supplementary feedstock when there is a shortage of coke oven gas, and it will be introduced at the stage of precise desulfurization); the process will involve pre-treatment, purification of the coke oven gas, shift reaction, decarburization, and deep cryogenic separation to isolate CH4 and CmHn from the gas. At the same time, Unit 1 and Unit 2 of the conversion unit as well as the waste heat boiler will be shut down; the hydrogen-rich gas separated by cryogenic methods will be mixed with nitrogen in a ratio of 3:1 and used in the existing ammonia synthesis plant to produce 150,000 tons of liquid ammonia per year. Upon completion of the technical upgrades for this project, the entire plant will have a production capacity of 150,000 tons per year of synthetic ammonia, along with 90,000 tons per year of LNG, achieved through the combination of existing facilities and new installations; the synthetic ammonia production capacity remains unchanged before and after the upgrades. Project Overview, Process Technology and Equipment Selection: This project involves an LNG production facility using residual coke oven gas, along with a technological upgrade for the synthesis of ammonia. The coke oven gas is purified, compressed, subjected to shift reaction (primary), decarburization (primary), methanation, and deep cryogenic separation to produce LNG. The non-condensable gases obtained through deep cryogenic separation are mixed with hydrogen and nitrogen before being fed into Ningxia Yufeng’s existing facility, which produces 150,000 tons per year of ammonia from coke oven gas. For the gas separation and purification in the LNG production process of Project L, cryogenic separation is employed. Gas liquefaction is achieved through a mixed refrigerant cycle combined with a nitrogen refrigeration cycle and liquid nitrogen washing. The LNG is stored in 5000 m3 atmospheric-pressure LNG storage tanks (fully metallic tanks); the equipment selected is appropriate and complies with energy-saving standards and regulations. Annual comprehensive energy consumption and types after the project is completed and reaches full capacity: The main types of energy consumed by the project are electricity and excess coke oven gas. The annual electricity consumption is 302.954 million kWh, and the consumption of residual coke oven gas is 480 million cubic meters. The annual production of LNG amounts to 90,000 tons. Once the technical upgrades are completed and the plant is operating at full capacity, the total comprehensive energy consumption will be 156,621.04 tce (in equivalent terms) and 207,911.15 tce (in equivalent value). Among them, for the product line producing 90,000 tons of LNG per year, the monthly increase in total energy consumption is 4,399.37 tce (in equivalent terms) and 27,618.65 tce (in equivalent value). Ningxia Yufeng Chemical Co., Ltd. was established on June 20, 2011. It is a key enterprise for investment attraction by the people’s government of Zhongwei City. The company’s projects include an ammonia production facility with an annual capacity of 150,000 tons, as well as a project to produce LNG at an annual rate of 90,000 tons by utilizing coke oven gas from the first and second phases of Ningxia Weizhong Energy’s operations, which have an annual output of 2.4 million tons of coke oven gas. These projects represent examples of initiatives that are currently encouraged for development, as well as projects related to comprehensive resource utilization and a green, low-carbon circular economy.