Major breakthrough achieved in research on direct synthesis of olefins from syngas

Thread Content

Major breakthrough in direct conversion of syngas into olefins Author/Source: Date: 10-08-2016 Clicks: 43 The journal Nature published important findings on October 6th, reporting that a research team jointly formed by the Shanghai Institute of Advanced Study and ShanghaiTech University has made significant progress in the direct conversion of syngas into olefins. The project leader is Researcher Zhong Liangshu, with Shanghai University, East China Normal University, the Institute of Physics of the Chinese Academy of Sciences, and the Institute of Chemistry of the Chinese Academy of Sciences also contributing to some of the work. By adopting a novel catalyst active site structure, this study achieves the high-selective direct synthesis of olefins from syngas under mild conditions, which is of great significance for advancing the field of syngas catalytic conversion. At the same time, this achievement brings high economic benefits and will promote the development of coal chemical industry in our country. TEM image of the FTO catalyst. a, b, low-magnification TEM images ； c, d, e, high-magnification TEM images ； f, Schematic diagram of Co2C parallelepiped nanoparticles. In the field of energy and chemicals, olefins are a fundamental and highly valuable chemical raw material with high added value; many products such as synthetic fibers, synthetic rubbers, synthetic plastics, high-performance lubricants, higher-carbon alcohols, and high-density jet fuel are all manufactured using them as their basic raw materials. Therefore, the development level of the olefin industry and the balance between market supply and demand directly affect the development level and scale of the entire chemical industry. In recent years, to reduce dependence on petroleum resources, research at home and abroad has focused primarily on non-petroleum routes, that is, using coal or natural gas resources to directly or indirectly produce olefins. The current mainstream process involves first producing syngas from coal or natural gas (whose main components are carbon monoxide and hydrogen, namely CO and H2), then converting this syngas into methanol, and finally producing olefin products through methanol conversion routes (including the MTO process for converting methanol into ethylene and propylene, as well as the MTP process for converting methanol into propylene). This technology involves two main steps: the synthesis of methanol from syngas using a copper-based catalyst, and the conversion of methanol into olefins using a molecular sieve catalyst. If the number of reaction steps can be reduced and syngas can be directly converted into olefins with high selectivity, the process will be shorter and require less energy. The direct synthesis of olefins via the Fischer-Tropsch route using syngas refers to the process in which CO and H2, under the action of a catalyst, are used to synthesize olefins through the Fischer-Tropsch (abbreviated as FT) reaction pathway (also known as FTO). Currently, the main challenges in FTO are the improvement of olefin selectivity and the effective control of product distribution. Since FTO is a highly exothermic reaction, the excessive heat of reaction can easily lead to local overheating and temperature spikes, thereby promoting methanation and carbon deposition. The large amount of methane generated significantly reduces the overall yield of olefins. Furthermore, since olefins act as intermediate products during FT synthesis, they are highly prone to undergo secondary hydrogenation reactions to form saturated alkanes, thereby further reducing olefin selectivity. Given that the route for directly producing olefins from syngas is constrained by the factors mentioned above, it is necessary to develop entirely new catalytic active site structures in order to achieve excellent FTO catalytic performance, along with low methane selectivity and high olefin selectivity. Direct and efficient production of olefins from coal-based syngas: The Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Institute, Chinese Academy of Sciences (Low-Carbon Conversion Laboratory) is primarily engaged in the research and development of core technologies for the low-carbon conversion of carbonaceous resources. It has been focusing on the study of the structure-activity relationships and reaction networks involved in the catalytic conversion of syngas, as well as on the development of catalysts. Recently, the Low-Carbon Conversion Laboratory has creatively developed a new catalyst. It was found that under mild reaction conditions (250 oC and 1–5 atm), this catalyst enables the high-selective direct synthesis of olefins from syngas, with a methane selectivity as low as 5%, a selectivity for low-carbon olefins of up to 60%, and an overall olefin selectivity of over 80%. The olefin/alkane ratio can reach more than 30, demonstrating excellent FTO performance. To determine the nature of the catalyst’s active sites, the laboratory conducted in-depth structure-activity relationship studies combined with theoretical calculations, and identified that the structure of these active sites is a Co2C nanoprism with exposed surfaces of {101} and {020}. The relevant results of the aforementioned work were published in the journal Nature. Given China’s resource profile of limited oil and gas resources but abundant coal, this technology holds great prospects for industrial application and high economic benefits. At present, the Shanghai Advanced Research Institute of the Chinese Academy of Sciences has reached agreements with partner companies such as Shanxi Lu’an Group to collaborate on areas including the scale-up production of catalysts, reactor design, and process development, with the aim of achieving industrial demonstration and commercialization as soon as possible in order to promote the development of coal chemical industry in China.