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Ningxia Yufeng Chemical’s 90,000-ton/year LNG production project using coke oven gas goes into operation Author/Source: Gasification World Date: April 28, 2023 Clicks: 78 On April 24, it was learned from Baoji Taihe Petrochemical Engineering Co., Ltd. that the 90,000-ton/year LNG production facility built using this company’s technology by Ningxia Yufeng Chemical Co., Ltd. had seen its main construction completed by the end of December last year, as a result of nearly a year’s effort on the part of the construction team. On April 12 this year, various processes began to operate with gas fed into the system for trial production, and qualified LNG was produced on the 16th. After 72 hours of continuous and stable operation, the production rate of LNG exceeded 10 tons per hour, fully meeting the design capacity of the facility. It is understood that Ningxia Yufeng Chemical is a key enterprise for investment attraction by the people of Zhongwei City. In 2012, the company made use of the 30,000 cubic meters per hour of coke oven gas surplus produced by Ningxia Yuguang Energy Industry Co., Ltd. in the Zhongwei Industrial Park in Ningxia, and through catalytic conversion, it invested in building a synthetic ammonia production facility with an annual capacity of 150,000 tons. In order to make full use of the 60,000 cubic meters per year of coke oven gas generated as a by-product in the first and second phases of Ningxia Yuguang Energy’s facilities, with a total production capacity of 2.4 million tons per year, and to further expand production scale and adjust the product mix, in November 2021, Ningxia Yufeng Chemical decided to carry out technical upgrades to the existing ammonia synthesis plants, making rational use of some of those facilities. On top of the existing plant capable of producing 150,000 tons of ammonia per year from coke oven gas, they planned to build a project that utilizes coke oven gas to produce 90,000 tons of LNG per year as part of a circular economy approach. It is reported that the key technological improvement in this project involves integrating the production of LNG alongside synthetic ammonia; the original synthetic ammonia process has been optimized through modifications such as pretreatment, purification, reforming, decarburization, deep desulfurization, and methanation of coke oven gas. For the separation and purification of process gases, cryogenic separation methods are used, while gas liquefaction is achieved through a mixed refrigerant cycle combined with a nitrogen refrigeration cycle and liquid nitrogen washing. This approach enables the separation of CH4 and CmHn from the gases. At the same time, Section 1 and Section 2 furnaces of the conversion unit as well as the waste heat boiler in the existing ammonia synthesis plant will be shut down; the hydrogen-rich gas separated by deep cooling will be mixed with nitrogen in a 3:1 ratio to be used in the existing ammonia synthesis plant to produce 150,000 tons of liquid ammonia per year. The main energy sources consumed in this project are electricity and excess coke oven gas; the annual consumption of electricity is 302.954 million kWh, while the consumption of excess coke oven gas is 480 million cubic meters. The annual production volume of LNG is 90,000 tons. Wang Wanhe explained that, based on the current conditions in the LNG market, the project generates an additional annual revenue of 450 million yuan for the company, as well as an additional annual profit of 225 million yuan. At the same time, the capacity of the company’s existing ammonia synthesis plants also increased slightly, and processes such as catalytic conversion were discontinued, which reduced consumption and improved efficiency. The overall market competitiveness of the enterprise **has improved**. 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 for the production of 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 storage is carried out in 5000 m3 atmospheric pressure LNG storage tanks (fully metallic tanks). The equipment selected is appropriate and complies with energy-saving standards and specifications. 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 for resource utilization and the promotion of a green, low-carbon circular economy.