Breakthrough achieved in co-gasification of coal and natural gas

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Breakthrough in Co-gasification of Coal and Natural Gas Author/Source: Date: 11-22-2018 Clicks: 9. A few days ago, the key research project undertaken by the Northwest Chemical Industry Research Institute for Yanchang Petroleum Group, titled “Pilot Study on Synthesis Gas Production through Co-gasification of Coal and Natural Gas,” was completed following multiple tests conducted in Xingping, Shaanxi. Breakthrough progress was achieved, and thanks to its independent innovation efforts, the institute developed another original gasification technology for Yanchang Petroleum. In practical production, the atomic composition of coal, characterized by a high proportion of carbon and a low proportion of hydrogen, requires the use of shift reactions to adjust the carbon-to-hydrogen ratio during the conversion of coal into syngas, resulting in significant emissions of carbon dioxide. Some companies reduce carbon dioxide emissions and improve resource utilization efficiency by fully integrating the production of syngas from coal with that from natural gas, which has a higher hydrogen content and lower carbon content; this is achieved by operating two gasification systems in parallel and mixing the syngas produced by these systems to achieve a balance of hydrocarbons and elements. With the support of the leadership of Yanchang Petroleum Group, the Northwest Research Institute, through a series of targeted studies, creatively proposed a technical approach that involves introducing water-coal slurry and natural gas into the same gasifier via multiple channels and one or several nozzles, in order to produce syngas together. This approach aims to further enhance the efficient conversion of coal and natural gas as well as energy coupling, reduce equipment investment, increase the operational flexibility of the equipment, and lower production costs. During the reaction process, the gas-solid ratio is increased by introducing natural gas, which raises the gas flow velocity inside the furnace, enhances the atomization of the feed coal, expands the effective reaction volume within the furnace, increases the conversion rate of carbon in the feed coal, and reduces oxygen consumption as well as raw material usage. At the same time, by adjusting the feed ratio of coal to natural gas, the composition of the syngas can be flexibly modified (the H2/CO ratio in the syngas can be adjusted within the range of 1.1–1.5), to suit various chemical syntheses, and it is also easy to increase the production capacity of a single furnace. After multiple industrial pilot tests, the project accumulated a total of approximately 360 hours of effective testing time, and passed the on-site acceptance test based on 72 hours of continuous stable operation. The test results show that the carbon conversion rate in the raw coal is greater than 98%, the effective conversion rate of natural gas is greater than 90%, and the content of useful gases in the syngas exceeds 92%. Compared with the \"water-coal slurry gasification + partial oxidation of natural gas\" process route, this technical setup reduces oxygen consumption by about 5%, coal consumption by about 2%, and natural gas consumption by about 1% per thousand cubic meters of useful gas produced. The test also verified the reliability of core equipment such as the gasifier and nozzles, as well as the feeding control systems for slurry, natural gas, and oxygen. The successful pilot-scale demonstration of the technology for co-gasification of coal and natural gas to produce syngas means that the Northwest Research Institute of Chemical Engineering has become the first company in China to possess proprietary technology for the fluidized-bed co-gasification of solid, liquid, and gaseous feedstocks. This advancement helps to change the situation in China’s coal chemical industry, where only one type of feedstock is used, by enabling the rational utilization of coal, natural gas, and other hydrocarbon resources. It reduces equipment investment, energy consumption, and resource usage, thereby lowering carbon emissions and contributing to the development of a greener industrial sector. Additionally, this technology can be applied to the co-gasification of coal with other organic gases, helping to reduce pollution from organic waste gases and enable their recycling. This technology also holds great practical significance for the peak-shaving utilization of natural gas after production and for promoting the development of the chemical industry.