Nature confirms a milestone breakthrough in China’s coal-to-olefins technology: high efficiency and low consumption

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Nature confirms a milestone breakthrough in coal-based olefin production in China: high efficiency and low consumption. Author/Source: Date: 2016-03-07. Clicks: 16. Recently, the internationally renowned journal Nature has confirmed another major breakthrough in Chinese science and technology. On March 4, Bao Xinhe, a representative of the Ren faction, researcher at the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences (hereinafter referred to as the \"Dalian Institute of Chemical Physics\"), and academician of the Chinese Academy of Sciences, revealed this latest research finding. 　　It is reported that the team led by Academician Bao Xinhe (currently the executive vice president and professor at Fudan University) and Researcher Pan Xiulian has made a significant breakthrough in the research on direct olefin production from coal gasification, overturning the Fischer-Tropsch route (abbreviated as F-T) that has been used in coal chemical processing for over 90 years. By abandoning the water-gas shift process for hydrogen production, which involves high water and energy consumption, they creatively utilized the syngas generated from coal gasification – a mixture of purified CO and H2 – and, with the help of a new type of composite catalyst, achieved high-selectivity in the one-step production of low-carbon olefins. This approach resolved the dilemma in traditional coal chemical catalytic reactions, where activity and selectivity often trade off against each other, providing guidelines for the design of efficient catalysts and catalytic reaction processes. This achievement has been hailed by the industry as a \"milestone breakthrough in the field of coal conversion.\" Nature acknowledges a landmark breakthrough in coal-to-gas technology in China: high efficiency and low consumption. On March 4th, Academician Bao Xinhe, who is renowned nationwide, presented these achievements at the Institute of Physics, Chinese Academy of Sciences, in Beijing. 　　Olefins are one of the most important raw materials in modern industry. In our country, olefins are primarily obtained from petroleum refining, which poses significant costs and environmental challenges; therefore, coal-based chemical processing as an alternative to petroleum-based chemical processing represents a new path for energy development that has been explored in our country in recent years. 　　This research achievement was published in the American journal Science on March 4, and applications have been filed for Chinese invention patents as well as international PCT patents. The same issue of Science published an expert commentary titled “Surprised by Selectivity,” arguing that this process will be highly competitive in industrial applications in the future. 　　In 1923, the Fischer-Tropsch process was invented by German scientists Fischer and Tropsch, which uses syngas to produce high-carbon chemicals and liquid fuels from coal. Although this process is not perfect – it generates large amounts of carbon dioxide, consumes a lot of water, has poor product selectivity, and requires significant energy for subsequent processing – the international energy and chemical industries continue to consider it irreplaceable. 　　Today, this process has been overturned by researchers at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences—they abandoned the water-gas shift hydrogen production method, which is characterized by high water and energy consumption, and instead used the mixed gas generated from coal gasification (after purification) to obtain low-carbon olefins with high selectivity. When the one-way conversion of CO is 17%, the selectivity for low-carbon hydrocarbon products reaches 94%, with the selectivity for low-carbon olefins (ethylene, propylene, and butylene) being greater than 80%. It broke the limit of the traditional Fischer-Tropsch synthesis process, where the selectivity for low-carbon olefins was at most 58% (the SF limit). 　　The traditional F-T process uses metals (in reduced form) as catalysts. On the surface of metal catalysts, CO molecules are activated and dissociated into C atoms and O atoms. These C and O atoms react with hydrogen adsorbed on the catalyst surface to form methylene (CH2) intermediates, while water molecules are released. The methylene intermediates undergo free polymerization on the catalyst surface through a migration insertion reaction, yielding hydrocarbon products with different numbers of carbon atoms (ranging from one to thirty, and sometimes even up to hundreds of carbon atoms). The carbon atom number distribution of the hydrocarbon products in the entire reaction is wide, resulting in low selectivity for the target product. At the same time, this process requires a large amount of hydrogen to remove the O atoms generated by the dissociation of CO on the surface of the metal catalyst, and this valuable hydrogen is obtained through water-gas shift reaction (CO + H2O → H2 + CO2). The water-gas shift reaction is an energy-intensive process that also results in the release of large amounts of CO2. 　　The process developed by researchers at the Dalian Institute of Chemical Physics uses partially reduced composite oxides as catalysts. CO molecules adsorb onto the oxygen-deficient sites of these catalysts and dissociate; gaseous hydrogen molecules then react selectively with the resulting C atoms to form methylene radicals. Meanwhile, the oxygen atoms generated from the dissociation of CO on the catalyst surface tend to react with another CO molecule, forming CO2. Unlike the traditional F-T process, the methylene radicals generated at oxygen-deficient sites do not remain on the catalyst surface or undergo surface polymerization reactions; instead, they quickly enter the pores of the molecular sieve, where they undergo selective coupling reactions in the confined environment of those pores, resulting in the formation of low-carbon olefins and thereby **increasing the selectivity of the products**. By regulating the pore structure and acid properties of molecular sieves, the product molecules can be modified in a controlled manner. Nature confirms a milestone breakthrough in coal-to-gas production in China: high efficiency and low consumption. This breakthrough eliminates the excess oxygen atoms involved in the formation of hydrocarbons by using CO instead of H2; it does so without altering the total CO2 emissions, thereby eliminating the energy- and water-intensive water-gas shift reaction. In principle, it opens up a new pathway for converting coal with low water consumption (no water cycle involved in the process), successfully addressing the question that has long concerned the Premier – namely, whether it is possible to carry out coal chemical processing without or with minimal use of water. 　　At the same time, Academician Bao Xinhe’s team creatively combined oxide catalysts with molecular sieves, thereby effectively separating two types of catalytic active centers: those responsible for CO activation and those responsible for intermediate coupling. This approach allowed the “free radicals” that arise in traditional Fischer-Tropsch processes in a random and uncontrolled manner to be confined within a “cage” (the molecular sieve); by restricting their behavior, these free radicals were transformed into the desired target products, namely low-carbon olefins. It overcomes the \"see-saw\" problem of trade-offs between activity and selectivity in traditional catalytic reactions, providing a guide for the design of efficient catalysts and catalytic reaction processes. 　　In addition to water conservation and reducing CO2 emissions through improved processes (by shortening procedures and lowering energy consumption), the new invention developed by Academician Bao Xinhe’s team also offers significant economic benefits. According to the preliminary assessment by Sinopec Engineering Construction Co., Ltd. (SEI), under the current conditions, the internal rate of return (IRR) for this project can exceed 14%. 　　“Technology must provide support for the ‘energy revolution’. ”Bao Xinhe said that many chemical companies, both domestic and international, are very interested in the further application and promotion of this process. Following careful evaluation and consultations, the Dalian Institute of Chemical Physics has now reached preliminary agreements with major domestic chemical enterprises as well as renowned foreign chemical companies to work together on areas such as catalyst preparation and process development, with the aim of achieving industrial demonstration and commercialization as soon as possible, and striving to turn this original achievement into real productive capacity. 　　When Dr. Schwab, an expert from Germany’s BASF company who had been working on research related to the FTTO process for producing olefins for over twenty years, learned about the basics of this process, he said in frustration, “Why didn’t we think of this idea first?” ”Academician Bao Xinhe replied with pride, “You’ve already come up with so many ideas; it’s time for us now.” 　　The confidence behind these words stems from the dedication of an excellent research team over several decades, as well as China’s growing capabilities in scientific research: for this single study alone, the team spent more than nine years working in collaboration with various domestic research institutions, including the Hefei Synchrotron Radiation Facility, and making use of various high-end research devices developed independently. During this period, aside from filing multiple Chinese invention patents and international PCT patents, the team did not publish a single article on related research. 　　The research on related projects has been funded by the **National Natural Science Foundation of China, the Ministry of Science and Technology, and the Strategic Priority Research Program of the Chinese Academy of Sciences. The original title is: Nature confirms a milestone breakthrough in China’s coal-to-gas technology: high efficiency and low consumption. It must be wrong; it should be coal-derived olefins.