Isothermal shift technology for the first use in synthetic ammonia HT-L gas

Thread Content

Use of Isothermal Shift Technology in the Production of HT-L Gas for Ammonia Synthesis Author/Source: China Chemical Industry News Date: November 13, 2015 Clicks: 337 On November 10, reporters learned from Xinjiang Zhongneng Wanyuan Chemical Co., Ltd. that the company’s 300,000 tons per year ammonia synthesis plant and 520,000 tons per year urea production plant have been in operation successfully and stably for over two months now. This is the first application of the Anchun isothermal shift technology in the gas flow bed powder coal gasification process using an HT-L reactor for the conversion of high-CO crude syngas, thereby meeting the process requirements for a low CO content in the syngas used for ammonia production. The operation results show that, when compared with the design parameters, the performance of the isothermal conversion unit in this project meets all the design requirements and even exceeds them. According to Xu Shen, the chief project supervisor at Xinjiang Zhongneng Company, the gasification section of the company’s “30·52” project utilizes the HT-L pressurized coal gasification process, while the shift section makes use of isothermal low-temperature CO shift reactors and related system technologies developed by Hunan Anchun High-Tech Co., Ltd., which possess complete independent intellectual property rights. The core equipment in this system is the 3800-phase change heat transfer isothermal shift reactor, also developed by Anchun Company. The project was officially completed and put into production on August 22 this year, and the facility is currently operating stably. The inlet CO content of the isothermal shift system is 63.7%, with a water-to-gas ratio of 0.8; the outlet CO content is 0.62%, achieving a conversion rate as high as 99%. At full load, the resistance of the isothermal reactor is ≤0.02 MPa, and the system resistance is ≤0.1 MPa; 0.76 tons of steam at 4.0 MPa can be produced per ton of ammonia, thereby completely preventing overheating or uncontrolled temperature rises during startup and operation. Compared with traditional and other conversion technologies in use domestically, Anchun Company’s isothermal conversion technology features a small temperature difference within the catalytic bed, low system resistance, and high conversion efficiency. Its advantages of \"low temperature difference, low resistance, and high efficiency\" are quite evident; there are no hot spots, and the operation is natural, isothermal, making it a true isothermal conversion technology. It is understood that the phase-change heat transfer isothermal reactor and related application technologies passed the expert evaluation organized by the China Petroleum and Chemical Industry Federation at the end of last year. The evaluation committee deemed that the phase-change heat transfer isothermal reactor developed by Anchun Company has a rational structure and advanced technical specifications, reaching an internationally leading level; it also recommended accelerating the further development, promotion, and application of these technologies. The DDB phase-change heat transfer isothermal transformation reactor developed by Hunan Anchun has four main features: first, it enables precise control of the temperature in the reaction bed, with a temperature difference of <4°C; this results in high reaction efficiency, a long service life for the catalyst, and a high energy recovery rate ； Secondly, the radial distributor ensures even gas distribution, thereby effectively improving the utilization rate of the catalyst ； Thirdly, catalyst loading tubes are evenly distributed between the tube sheets in the design, ensuring uniform catalyst filling ； Fourth, it features a double-shell and double-sheet plate structure that effectively absorbs expansion stresses, ensuring safe use. The phase-change heat transfer isothermal shift reaction technology was first applied nationwide in 2012, and it has since been successfully used in the conversion of calcium carbide furnace exhaust gases with high CO content, as well as in the gasification conversion of water-coal slurry and pulverized coal, having withstood thorough market testing. This technology is applicable both to newly installed units and to the retrofitting of conventional conversion units. It can be used in calcium carbide furnace exhaust gases, as well as in various coal chemical plants for producing synthetic ammonia from coal, natural gas from coal, hydrogen from coal, oil from coal, ethylene glycol from coal, methanol from coal, olefins from coal, and sulfur from H2S. It is suitable for CO conversion of gas produced by pressurized continuous gasification of pulverized coal, pressurized continuous gasification of coal slurry, and batch fixed-bed gasification. Its technical and economic advantages are particularly evident in cases of CO conversion involving high CO levels and high gas-to-gas ratios.