Thread Content
International Advanced Technology for Continuous Gasification Using Low-Pressure Pure Oxygen – Author/Source: Sinochem News Network; Date: June 28, 2020; Clicks: 7. This technology features strong compatibility with various raw materials, low investment requirements, excellent gasification performance, and a carbon conversion rate of ≥99.5%. On June 23, the Chinese Chemical Society held a video evaluation meeting in Beijing to assess the scientific and technical achievements of the “Low-Pressure Pure Oxygen Continuous Gasification Technology (DY Changyu Furnace)” project developed by Jiangxi Changyu Industrial Co., Ltd. A scientific and technological achievement evaluation committee composed of 8 renowned domestic experts from institutions such as the Chinese Chemical Society, the Petroleum and Chemical Industry Planning Institute, Shanghai Damen Chemical Engineering Technology Co., Ltd., and East China University of Science and Technology, in fields including petrochemicals, chemical engineering planning, chemical process and systems engineering, coal chemical industry, production and design technologies for nitrogen fertilizers, and chemical engineering, unanimously agreed that this technical achievement is innovative and possesses independent intellectual property rights; its overall performance is at an internationally advanced level, and they approved its evaluation as a scientific and technological achievement. At the same time, it is recommended that project owners accelerate the renovation of existing outdated gasification technologies as well as their promotion and application in suitable fields. Tang Wanjin, the chief engineer of CHANGYU Company, told reporters that this technology has been adopted and applied in various industries across the country. To date, more than 400 sets of DY CHANGYU furnaces are in use by enterprises in sectors such as petrochemicals, non-ferrous metallurgy, coal chemistry, coal coking, and ceramics, delivering good economic and environmental benefits. Industrial application results show that this furnace type has strong adaptability to various raw materials, requires low investment, and exhibits excellent gasification performance: gas generation rate ≥ 1500 Nm3/h•m2, carbon conversion rate ≥ 99.5%, effective gas composition of 82–86%, specific coal consumption of 440–460 kg, specific oxygen consumption of 210–220 Nm3, specific steam consumption of 440–590 kg, steam decomposition rate of 75–80%, and residue carbon in ash ≤ 0.6%. At the same time, 11 new invention and utility model patents were developed, including a method for producing water gas through continuous oxygen-based gasification in a fixed-bed system, a method for automatic slag removal from a gasifier using a track system, and a new type of dual-drive mechanism for the pressure-resistant bottom of fixed-bed gas generators. The evaluation committee noted that this achievement, through integrated innovative design and systematic optimization of coal gasification technology and gasifiers, has developed a new gasification technology with independent intellectual property rights, featuring multiple innovations: first, it adopts a low-pressure pure oxygen continuous gasification process, using pure oxygen instead of air as the gasifying 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, resulting in no purge gas emissions. This fills the gap at home and abroad in the field of fixed-bed systems for producing gas using low-pressure pure oxygen in a continuous manner. Secondly, an upright cylindrical furnace with a high height-to-diameter ratio was developed, which effectively increased the carbon layer height and gasification intensity, thereby improving the gasification efficiency. Thirdly, a jacket with a semi-tubular pressure-resistant structure featuring a high height-to-diameter ratio was developed; it can withstand pressures of up to 2.5 MPaG. This design increases the operational flexibility of the gasification furnace, provides good heat retention, reduces the likelihood of scarring, makes it less susceptible to high-temperature bubbling, prevents damage to the furnace grates, and ensures a long service life. According to Zheng Xiaolun, vice chairman of Changyu Company, Changyu is a comprehensive enterprise group engaged in gasification technology research and development, equipment manufacturing, project construction, and gas operation. It is a high-tech enterprise that possesses various gasification technologies as well as multiple independent intellectual property rights, and it also serves as a platform for high-level talents to innovate and start businesses. The company maintains a long-term strategic partnership in the areas of production, education, and research with China Dongfang Electric Group. It always focuses on technological research and development; it has a large-scale gasification R&D center, and employs numerous masters, doctors, and experts in gasification technology. It is currently the most capable team in terms of technological research and development in the field of gasification in China. The company has built several pilot-scale gasification platforms of different types, and possesses strong capabilities in equipment manufacturing. Tang Wanjin said that this technology represents a more advanced and environmentally friendly gasification method compared to fixed-bed batch gasifiers (UGI), single-stage furnaces, and two-stage furnaces. It provides an effective pathway for upgrading traditional fixed-bed furnace systems, as well as offering a cost-effective, high-performance technical solution for new coal chemical enterprises. News link: China is characterized by abundant coal but a shortage of oil and gas. In the coming period, coal will continue to play an important role as a fundamental energy source. Coal chemical industry represents an effective way to utilize coal in a clean and efficient manner, and it is also a crucial component of China’s industrial development. Coal gasification is the process of converting coal into clean gas, and it represents the key technology in coal chemical industry. Based on the way coal moves within the furnace, coal gasification techniques can be divided into three main categories: fixed-bed, fluidized-bed, and gas-flow bed. Some fixed-bed gasification technologies use air as the gasifying agent to produce coal gas, such as one-stage and two-stage furnaces, as well as intermittent gasifiers (UGI). As the earliest types of gasification technology introduced, these have been widely used and developed in China, making significant contributions to the growth of the country’s coal chemical industry. However, with the adjustment of industrial policies and the development of modern coal chemical technologies, traditional fixed-bed gasification technologies that use air as a gasifying agent have been classified as restricted types due to their environmental drawbacks, and their use is required to be phased out gradually. At present, the intermittent gasification (UGI) technology remains the dominant technique in China’s fertilizer industry. Its drawbacks include the inability to produce continuously, low production capacity per furnace, high emissions of waste gases during the production process, and a residual carbon content in the ash of around 20%, which is difficult to reduce further. If transformation using large-scale fluidized bed technology (water-coal slurry or pulverized coal gasification) is adopted, first, the investment is too high for most enterprises to afford; second, the raw material source must be changed from anthracite to bituminous coal and lignite; third, due to the high gasification pressure, most of the existing equipment cannot be used. From an economic and practical perspective, it is imperative to develop new processes and equipment based on fixed-bed gasifiers used for synthesizing syngas, in order to improve production efficiency and thermal efficiency, enhance the quality of the gas, boost environmental protection standards, and reduce production costs. To this end, Jiangxi Changyu Industrial Co., Ltd. has drawn on the advantages of existing fixed-bed gasification furnaces while overcoming their shortcomings, and developed a new type of low-pressure pure-oxygen continuous gasification furnace (DY Changyu Furnace) that features more advanced technology, higher energy efficiency, stable and reliable operation, as well as improved safety and environmental performance, providing technical support for companies undertaking new construction projects or those expanding their facilities.