By Holly Krutka
Executive Editor, Cornerstone
Dr. Li Yong-Wang is the founder and president of Synfuels China Technology Co., Ltd., a Beijing-based company focusing on advanced conversion technologies for coal, natural gas, and other energy assets since 2006. Dr. Li has also built up a series of subsidiary companies around the world. Synfuels China’s business is founded upon the expertise gained from research and development (R&D), three operational coal-to-liquid (CTL) plants, and the construction of the largest CTL plant in the world—producing 100,000 barrels of liquids per day (bpd), with an investment of about US$10 billion.
Considered one of the world’s top scientists focused on Fisher–Tropsch (FT) technology, Dr. Li is also a leading professor at the Chinese Academy of Science (CAS) in the Institute of Coal Chemistry. As the director of the Chinese National Engineering Laboratory of Indirect Coal Liquefaction and the National Energy Research Center for Clean Fuels From Coal, Dr. Li leads a research team that carries out advanced research projects in industrial coal and gas conversion processes.
Dr. Li has published more than 400 scientific papers, obtained more than 50 authorized patents, and holds one software copyright. His FT-focused research has won several international awards, such as Germany’s Alexander von Humboldt Award, several Chinese National Technology Invention and Scientific Innovation awards, and CAS’s Outstanding Science and Technology Achievement Prize.
Cornerstone sat down with Dr. Li to discuss what he sees in the future of coal conversion and the most pressing technological developments needed to address today’s energy challenges.
Q: What do you see as the advantages of Synfuels China’s indirect liquefaction technology?
A: Conventional FT slurry-phase processes operated in low-temperature mode, 220–250°C, can produce 400 tons of C3+ hydrocarbon products per ton of iron-based catalyst consumed. Employing a medium-temperature mode, 275°C, Synfuels China has pushed the productivity even higher, to 1200 tons of high-quality C3+ products per ton of proprietary iron-based catalyst used. Synfuels China’s CTL technologies and process demonstrates the further following advantages:
- The slurry-bed FT reactor can scale to a single-stage design producing 12,000 bpd, while other technologies can require dual-stage systems.
- The FT reactor can operate with a uniform temperature distribution, efficient recovery of reaction heat, easy catalyst-wax separation under automatic control, and online catalyst replacement to ensure the stable operation of the plant.
- The iron-based catalyst has high activity, high selectivity for C5+ (greater than 92%), and low methane selectivity (less than 3% by weight).
- There is a lower solid catalyst charge due to the ultra-active catalyst used.
- The FT process produces high-quality synthetic crudes with low oxygenates and about one-third fewer acids.
- The proprietary FT and product refining technologies are
easily retrofitted to CTL and gas-to-liquids (GTL) processes.
While other global companies may have a longer history of commercial technology deployment, Synfuels China has a rigorous R&D process that combines scientific knowledge with engineering expertise. By using the company’s proprietary technology, a potential partner has access to the most recent scientific research underlying that technology to develop the most efficient plant based on the project goals.
Synfuels China uses an integrated approach to project design and implementation that focuses on improving efficiency based on fundamental scientific research, discipline, and knowledge. Since each plant and process is unique, we are able to offer engineering design and construction plans based on the need of the client, so there is no “one-size-fits-all” plant design and each project is customized according to the techno-economic objectives for the proposed plant. Every case is different and different potential sites require different strategies—Synfuels China dedicates significant time from conceptual design to implementation to ensure the success of each project.
Q: Can you give us some insight into what you feel are the most pressing technology development needs for coal conversion and how Synfuels China’s research and development efforts are contributing to addressing these issues?
A: Converting coal to valuable end-products is an important technology in many parts of the world where coal is abundant, and natural gas or oil reserves are low. There are many areas where technological development is needed. For the FT process, the catalysts and the reactors work, but they are not optimal and improvements are needed. For example, through our integrated and rigorous R&D process, Synfuels China has already improved the overall energy conversion of its iron-based catalyst to close to the technical maximum of 45% and developed an efficient method for separating the wax from the catalyst. The challenges facing current conversion processes also include economic and environmental issues, such as wastewater management.
Synfuels China is working to address these challenges through improving the overall energy efficiency of their technology, which leads to lower costs and lower air and water emissions. Our most recent R&D effort focused on the proprietary step-wise liquefaction technology. This technology uses the newly developed direct hydro-treatment of coal, extracting part of the oil from low-rank and chemically active coals, and leaving the residue for syngas production. The syngas is then converted with our medium-temperature FT technology, leading to a significant improvement in energy conversion efficiency—for specific types of active coal, the overall energy efficiency of a plant is improved from 40–45% to 50–58%. The first project based on this new development is now in the planning stages and will combine the step-wise liquefaction technology with the company’s proprietary refining technology to produce super-clean gasoline.
Q: Specifically looking at catalysts for FT processes, scientists and engineers are principally focused on cobalt- and iron-based catalysts. What are the advantages and disadvantages of these approaches and what do you believe should be the focus for future FT catalyst development?
A: The catalyst is the fundamental key to the success of the FT process. BP, ConocoPhillips, Gulf, ExxonMobil, IFP, Johnson Matthey, Sasol, Shell, Statoil, and Syntroleum are among the companies that have developed a cobalt catalyst. At higher temperatures, cobalt catalysts produce excessive amounts of methane, so most development is focused on low-temperature FT synthesis applications. The catalyst must be designed with the choice of reactor predetermined. The reactor is also important as research has shown that cobalt catalysts are more active in fixed-beds, compared to slurry-bed reactors. However, slurry-bed reactors normally operate at a higher temperature (230°C) than fixed-bed reactors (210°C), so the productivity per gram of catalyst is actually higher in slurry-bed reactors.
Compared to the other metals suitable for FT reaction catalysts, iron is a cheap raw material and is, on average, 250 times less expensive than cobalt. Economically, aside from the raw material cost, a catalyst with higher activity and stability will last longer and cost less. While iron is believed to be more tolerant to poisoning (e.g., sulfur), the disadvantage is the iron catalyst can deactivate quickly, which requires additional catalyst input.
While the advantages of iron catalysts are numerous, the mechanism behind FT synthesis and the complexity of the iron catalyst transformations during activation and FT reactions are not fully understood. Some of this uncertainty is controlled by utilizing chemical-grade raw iron with minimal impurities. Structural and chemical promoters are used to improve the selectivity, activity, and reduce sintering compared to unmodified and unpromoted iron catalysts.
FT processes that use iron catalysts have greater control over product selectivity, either via changes in the process conditions or catalyst composition. For example, selectivity shifts from lighter to heavier hydrocarbons as the temperature is lowered. The product stream using iron-based catalysts depends predominately on the FT temperature, where low-temperature (200–250°C) FT reactions typically produce hydrocarbons longer than C21 and high-temperature (275–350°C) reactions will produce mostly light hydrocarbons.
Given the difference in the temperature and pressure at which cobalt and iron catalysts optimally operate, comparing catalysts tested at different conditions is potentially misleading. One of the critical objectives for developing more efficient catalysts is improving the useful life, activity, and stability of the catalyst so that it may be reused indefinitely with minimal additional catalyst input. Other general requirements for improving catalysts are high selectivity for desirable products (e.g., low methane and high C5+) and mechanical robustness (e.g., the optimal particle size and density). All of these characteristics are impacted by the reactor type, as well as the operating conditions and climate in which a plant is sited. A catalyst may react very differently in a lab environment versus, for example, a commercial-scale plant in Inner Mongolia.
The iron-based catalyst researched and developed by Synfuels China for our proprietary FT process is among the best. However, future R&D will also need to improve the catalysts used for upgrading and refining the FT synthetic crude product to marketable liquid fuels and chemicals. For example, super-clean gasoline is urgently needed in large cities in China, and supply can be insufficient or difficult to obtain from current oil refineries. Synfuels China has found that refining the synthetic crudes (i.e., syncrudes), from our proprietary FT process using an iron-based catalyst, into super-clean gasoline is more economical than refining the syncrudes into diesel. While this is mostly due to current market demand for clean transportation fuels and the global dominance of gasoline-fueled vehicles, one other reason for the higher economic efficiency of gasoline produced from coal-based syncrudes is that it is not technically efficient to refine cobalt-based FT syncrudes into gasoline due to their chemical composition. Since most indirect coal liquefaction technologies to this point have used cobalt-based catalysts at low temperatures in a reactor, the comparative advantage of Synfuels China’s iron-based catalyst and medium-temperature FT process is that the resulting syncrudes can be efficiently converted to a wide range of products—including diesel, gasoline, LPG, jet fuel, naphtha, etc.—whereas syncrudes from a FT process using a cobalt-based catalyst can have a more limited refining potential. While the advantages and disadvantages of each approach are too numerous to list in this interview, the future of catalyst development will need to focus on improving the activity, selectivity, productivity, stability, and lifetime of catalysts.
Q: What are your thoughts around how to best address the environmental challenges associated with the CTL industry, such as wastewater treatment in the FT process, energy efficiency, thermal efficiency, solid waste treatment, etc.? What is the approach of Synfuels China in addressing environmental issues compared to other global CTL leaders?
A: Synfuels China has focused its R&D efforts on improving the economics and minimizing the environmental impacts of its technologies and processes. This focus is motivated by a company culture that uses the most recent and advanced theories, tools, and other knowledge-based methods to address how technologies and processes can be improved and adapted in a rapidly changing market. While in the short run, many environment-driven changes to a technology or process can result in a large economic impact, Synfuels China takes an integrated approach that has demonstrated there can be immediate savings from increased technological efficiency.
Key areas of environmental R&D within the company include:
- Minimizing the environmental footprint of CTL plants, including integrated water management
- Advancing waste processing and disposal
- Using step-wise liquefaction scheme to increase efficiency, for suitable coals
- Producing sulfur-free, low-nitrogen, and low-olefin fuels
- Capturing and concentrating CO2 to greater than 99.8% (commercial grade)
- Minimizing input use, including feedstock and water, and recycling
- Using non-traditional feedstock like “waste” coal and other relatively low-cost inputs
Q: Specifically, what are your recommendations for CTL development in a carbon-constrained world?
A: Without additional installed carbon capture technology, Synfuels China’s existing CTL process can capture up to 70% of the CO2 emitted as a high-purity (>99.8%) commercially ready product for utilization, through enhanced oil recovery, and storage. The comparative ease of capturing CO2 in the CTL process makes this technology the least expensive option for initial commercial-scale demonstrations of carbon capture, utilization, and storage (CCUS) to learn more about market development, storage geology, pressure management, etc.
For some suitable low-rank coals, the step-wise liquefaction technology from Synfuels China will greatly improve the energy efficiency. That said, CTL and polygeneration plants have higher energy efficiencies than coal-fired power plants, which only access the heat potential of coal and not the potential of coal’s rich chemical composition. A higher energy (or thermal) efficiency means that more of the potential energy in coal is converted to usable energy in the final products. Thus, for the same amount of coal, less CO2 is emitted as more of the energy-rich carbon and other chemicals are converted into liquid products.
Q: Even if technical and environmental challenges associated with CTL are addressed, today’s energy market presents additional challenges. For example, in the face of China’s recent economic slowdown and transitioning energy mix and the depressed price of oil, what are the principal drivers for continued CTL projects in China and around the world?
A: Yes, currently oil is overproduced and the global price is quite low. However, as an example, our 4000 bpd plant in Inner Mongolia is still successful with a net profit of about US$8 per barrel of fuel products at the current oil prices, while many similar plants are losing money. Due to the increasingly smooth operations over the last five years, 70% of the capital investment is already recovered. While fuel prices in the U.S. tend to vary with the global oil price, the fuel prices in China are frequently higher and not equivalent to international oil prices. This is, in part, due to the energy taxation policy of China and also the fact that about 60% of oil is imported. The real situation is that the motor fuel price (and other end products) is currently at the level of US$100 per barrel of liquids (compared roughly to the global oil price of about ̴US$40 per barrel of crude) including the government tax of about US$25 per barrel of liquid fuel. This taxation policy is under discussion as the security of energy supply is a common national security concern. If China can use its own coal resources to produce liquid fuels, even on a limited scale, this may improve the affordability, availability, and quality of China’s fuel supply.
With historically low—and frequently volatile—energy prices, many places globally are facing increasing demand for power, fuels, and chemicals. To meet a growing population’s needs, energy security is key. Thus, even with more renewable energy and improved storage technologies, there will be a continued need for fossil-based fuels, lubricants, and chemicals. Therefore, Synfuels China and its affiliates’ vision is to advance toward an energy system that demonstrates “near zero” emissions due to high efficiencies and innovative integration strategies.
Despite market challenges, there are exciting opportunities around CTL. For example, there are enormous amounts of coal assets around the world, especially in the Americas, that would be ideal feedstock for Synfuels China’s proprietary CTL technology. Projects that offer plentiful coal reserves, developed markets, training for employees, comprehensive infrastructure, and adequate brackish water are prime opportunities where Synfuels China’s process could thrive.
The principal driver for continued CTL projects is integrated R&D by companies, laboratories, think tanks, universities, and other energy-focused institutions already involved in the commercialization of advanced conversion technologies. An important outcome of these collaborations will be a global network of public and private institutions engaged in research, development, and training for energy conversion-based global industry ready to address the world’s energy-related challenges.
Synfuels Americas, a subsidiary of Synfuels China, is already working with coal and gas producers that own energy resources that cannot be produced economically in today’s market. As the energy industry struggles with fluctuating energy costs, Synfuels China and its subsidiaries will help unlock untapped energy resources.
The content in Cornerstone does not necessarily reflect the views of the World Coal Association or its members.
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