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Jinneng Tianyuan Shanxi Chemical completed the upgrade of its intermittent furnace. Author/Source: Sinochem News Network. Date: February 25, 2022. Clicks: 18. The cost of producing 1 ton of ammonia was reduced by over 230 yuan, resulting in an annual benefit increase of 92 million yuan； 48,000 tons of coal were saved in terms of physical quantity each year, resulting in a reduction of 140,800 tons of CO2 emissions. On February 24, good news came from Jiangxi Changyu Industrial Co., Ltd.: Jinneng Tianyuan Shanxi Chemical Co., Ltd. successfully upgraded the existing fixed-bed intermittent gasification unit by adopting Changyu’s low-pressure continuous pure oxygen gasification technology (DY furnace). The unit has been able to operate safely and stably for nearly a year now, with various technical parameters exceeding the design values; its overall performance is at an internationally advanced level, making it a model for the upgrading of similar fixed-bed intermittent gasification units in the region. According to calculations, after the renovation, the production cost per ton of ammonia is reduced by more than 230 yuan, and an annual production capacity of 400,000 tons of synthetic ammonia can generate an additional profit of 92 million yuan ； An annual savings of 48,000 tons of coal in physical form is achieved, which is equivalent to a reduction of 140,800 tons of CO2 emissions per year. It has good economic benefits, as well as favorable environmental and social benefits. According to Liu Baoguo, the technical lead of the project and technical director at Changyu Company, the renovation plan for Jinneng Tianyuan’s fixed-bed intermittent gasifier must be carried out in accordance with the principles of “safety, energy conservation, high efficiency, and environmental protection.” It involves making comprehensive, revolutionary improvements and optimized designs to the existing intermittent gasifier in terms of its process, control systems, equipment structure, materials, and manufacturing. These changes are expected to significantly raise the gasifier’s reaction temperature, speed, and efficiency compared to conventional intermittent gasifiers, thereby helping to achieve the goal of reducing carbon emissions. The entire renovation project is divided into two phases. In phase one, 4 units were renovated to handle the finely ground anthracite that is difficult to gasify using current gap furnaces; in phase two, all 32 gap furnaces will be converted into low-pressure continuous pure oxygen gasification furnaces (DY furnaces). The renovation plan makes use of the existing factory buildings and coal transportation systems, carrying out the renovations in phases to ensure that production at the enterprise is not disrupted, while still guaranteeing completion and commissioning as soon as possible. Liu Baoguo said that in the first phase of the project, four furnaces equipped with new devices were successfully put into operation on March 29, 2021. Based on their production and operational performance, the actual operating data (averages) for the low-pressure pure oxygen Changyu DY furnace indicate that the gasification feedstock used is small-grained anthracite coal from Jincheng, with a particle size of 8–40 mm and a fixed carbon content of around 80%. The proportion of useful gases (CO + H2) produced by the pure oxygen furnace is 83%–85%. The coal consumption per ton of ammonia is 980 kg; steam consumption per ton of ammonia is 800 kg; oxygen consumption per ton of ammonia is 480 Nm³. The steam decomposition rate exceeds 75%, while the residual carbon content in the ash is less than 5%. For the 2.8-meter pure oxygen furnace, the gas generation rate reaches 9,000–10,000 Nm³/h. Liu Baoguo explained that after the renovation, Jinneng Tianyuan Company’s gas production system was equipped with comprehensive environmental protection facilities; the circulating cooling water used in gas production is fed into intercooling units, resulting in no waste gas emissions, and 120 kilograms of anthracite can be saved per ton of synthetic ammonia produced. Steam consumption for feeding into the furnace decreased by 800 kilograms, while the oxygen consumption per ton of ammonia increased by 480 Nm3. The gas generation blowers and Roots blowers were eliminated, which reduced electricity consumption; there is no noise at the site as well, making it more environmentally friendly and in line with **environmental protection requirements. The number of operators at these positions has also decreased by over 30%, the amount of maintenance work has dropped by over 80%, and the number of start-up and shutdown cycles has been reduced by over 90%. Coal feeding and slag discharge in the unit are protected by nitrogen and steam purging; high-temperature radar carbon detectors are used for carbon layer measurement. The sealing is reliable, with no leaks. The process is simple, featuring one-way gasification with no backflow of gas, thus offering higher safety. The comprehensive safety facilities in place meet the requirements for safe production. The Changyu DY furnace features a high degree of automation and comprehensive safety (interlock) measures, enabling operation of the production facility without any human presence on site. Liu Baoguo said. According to Zheng Yuanlun, Chairman of Changyu Company, to date, Changyu’s low-pressure pure oxygen gasifier has been widely used in over 30 enterprises across various industries nationwide, including petrochemicals, fertilizers, coal chemical industry, coal coking, metallurgy, non-ferrous metals, new energy, and new materials. The longest continuous operation period without any major maintenance has exceeded six years. Zheng Yuanlun stated that the low-pressure pure oxygen continuous gasification DY Changyu furnace is a new type of gasification technology independently developed by the company, with fully independent intellectual property rights. It has successfully undergone an evaluation of its scientific and technological achievements organized by **authoritative institutions. Following the evaluation, industry experts unanimously agreed that the technology’s overall performance reaches international advanced levels, and it features multiple innovative aspects. Firstly, a low-pressure pure oxygen continuous gasification process is employed, using pure oxygen instead of air as the gasification agent. The gasification pressure is increased from atmospheric pressure to around 0.1 MPa, which effectively enhances the gasification reaction and replaces the high-volume, high-velocity purge gas system; there is no purge gas emission, thereby filling the gap in the field of fixed-bed systems where low-pressure pure oxygen is used for one-way continuous gas production, both domestically and internationally. Second, a vertical cylindrical furnace with a large height-to-diameter ratio was developed, which effectively increased the carbon layer height and gasification intensity, thereby improving the gasification efficiency. Thirdly, a jacket for a semi-tubular pressure-resistant structure featuring three tandem chambers with a high height-to-diameter ratio has been developed. It can withstand pressures of 1.3–2.5 MPaG. This design enhances the operational flexibility of the gasifier; it also offers good heat storage capacity, is resistant to scaling and high-temperature bubbling, prevents damage to the grate, and boasts a long service life. Zheng Yuanlun said that this technology builds on the advantages of existing fixed-bed gasifiers while overcoming their shortcomings, thereby developing a new type of low-pressure pure-oxygen continuous gasification technology (DY Changyu furnace) that is more advanced, offers higher energy efficiency, operates in a stable and reliable manner, and is also safer and more environmentally friendly. This is a more advanced and environmentally friendly gasification technology compared to fixed-bed batch gasifiers (UGI), single-stage furnaces, and two-stage furnaces. It provides an effective technical solution for upgrading traditional fixed-bed furnace systems, and it also offers a cost-effective, high-performance technology choice for the construction of new coal chemical plants or for the expansion of existing ones.