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Public announcement on the environmental impact assessment for Weihua Group’s project to produce 500,000 tons per year of synthetic ammonia and 800,000 tons per year of urea. Author/Source: Energy & Chemical Industry Updates. Date: April 24, 2023. Clicks: 26. The implementation plan for upgrading the existing facilities at Weihua Group has been approved by the provincial authorities. The current production capacity of the plant consists of a 520,000 tons per year urea production unit, a 200,000 tons per year methanol production unit, and an 110,000 tons per year dimethyl ether production unit – totaling 830,000 tons per year. This capacity is to be upgraded to 800,000 tons per year of urea production, which involves upgrading the 500,000 tons per year synthetic ammonia production unit and the 800,000 tons per year urea production unit, as well as replacing the boiler system with one that can handle 240 tons per hour of heat output. On-site upgrading and renovation projects such as the renovation and construction of an air separation unit with a capacity of 60,000 standard cubic meters per hour. The upgrade and transformation utilize Jinhua furnace gasification, Co-Mo sulfur-resistant shift reaction, domestically produced low-temperature methanol washing, domestically produced liquid nitrogen washing, domestic low-pressure ammonia synthesis technology, as well as the high-efficiency and low-energy-consuming urea production process developed by Wuhuan Engineering Company. The total investment for the project is 4,343.51 million yuan. The first phase of the Shaanxi Weihe Coal Chemical Group, with an annual production capacity of 300,000 tons of synthetic ammonia and 520,000 tons of urea, came online in 1996. Phase II has an annual production capacity of 200,000 tons of methanol and 110,000 tons of dimethyl ether, and it came online in 2006. Phase 3 involves 400,000 tons of methanol, with commissioning in 2011. Phases I, II, and III all use GE coal-water slurry gasification. In April 2023, Shaanxi Weihe Coal Chemical Industry published a draft of the project’s environmental impact assessment report on its official website for public comments. Explanation of the on-site upgrading and modification process at Shaanxi Weihua: Process flow – The raw coal is processed into coal slurry and then gasified in Jinhua furnaces to produce the raw gas required for ammonia synthesis. In addition to supplying raw gas for this project, the gasification unit also provides raw gas for the existing Phase 3 project. The raw gas produced by the gasification unit undergoes Co-Mo-based sulfur-resistant shift reaction, which converts carbon monoxide in the raw gas into hydrogen. The acidic gases and other impurities in the feed gas are then removed through low-temperature methanol washing and gas purification, yielding purified gas and carbon dioxide. The purified gas is used to produce ammonia in an ammonia synthesis unit, and then ammonia is used to synthesize urea in a urea production unit. The allocation for each process is as follows. Gasification employs the Jinhua furnace gasification technology; the combustion chamber of this furnace features a water-cooled wall design, while the lower section makes use of radiant waste heat recovery technology. Install 3 gasifiers, with 2 in operation and 1 as a backup. The effective gas volume for gasification (CO+H2) is 283,400 m3/h. Gasification is carried out at a pressure of 6.5 MPa and a temperature of 1250°C. Create new. The conversion process utilizes a Co-Mo-based sulfur-resistant conversion technology, with a three-stage adiabatic conversion sequence. It can handle 148,400 m3/h of effective gas (CO+H2). Create new. Purification: The purification system includes acid gas removal and gas refining. Acid gas removal employs a domestically produced low-temperature methanol washing process, with a processing capacity of 148,000 m3/h for gaseous materials (CO+H2). The main components include a washing tower, an H2S concentration tower, a thermal regeneration tower, a methanol-water separation tower, an exhaust gas washing tower, and a nitrogen stripping tower ； Gas purification employs a domestically produced liquid nitrogen washing process, with a processing capacity for useful gas (CO+H2) of 144,900 m3/h. It mainly includes a nitrogen washing tower, coolers, and a fuel gas separator. Create new. For ammonia synthesis, domestic low-pressure ammonia synthesis technology is employed, with the synthesis pressure controlled at around 15 MPa; the tower internals feature a three-bed structure with two intermediate heat exchangers. The scale is 500,000 tons. Freezing is cooled using an ammonia centrifugal compressor. Create new. For urea synthesis, the technical solution of \"high-efficiency synthesis and low-energy-consuming urea production process\" developed by China Wuhuan Engineering Co., Ltd. is adopted. The scale is 800,000 tons. It mainly includes the urea synthesis tower, medium-pressure decomposition and recovery, low-pressure decomposition and recovery, evaporation and granulation, treatment of process condensates, the pickling system, etc. Create new. Sulfur recovery is achieved through air oxidation + partial combustion + a three-stage Claus process to produce liquid sulfur, with a granulation step in place to obtain solid sulfur. The sulfur recovery flue gas is sent to the boiler flue gas desulfurization system after combustion. Create new.