Progress of domestic coal-to-oil projects and analysis of key technologies

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Progress of Domestic Coal-to-Oil Projects and Analysis of Key Technologies Author/Source: Huahua Network – Coal Chemical Industry (Author: Wang Shoujian, Chief Engineer of China National Chemical Engineering Corporation) Date: 2018-03-19 Clicks: 19 Article by Wang Shoujian, Chief Engineer of China National Chemical Engineering Corporation Progress of Coal-to-Oil Projects As of June 2017, there were 6 coal-to-oil projects in operation in China, including the Shenhua Ordos project with a capacity of 1.08 million tons per year for direct liquefaction, the Inner Mongolia Yitai Ordos project with a capacity of 160,000 tons per year for indirect liquefaction, the Shanxi Lu’an Changzhi project with a capacity of 160,000 tons per year for indirect liquefaction, the Shenhua Ordos project with a capacity of 180,000 tons per year for indirect liquefaction, the Yankuang Yulin project with a capacity of 1 million tons per year for indirect liquefaction, and the Shenhua Ningmei project with a capacity of 4 million tons per year for indirect liquefaction. The status of coal-to-oil operation projects is shown in Table 1. http://img.yf116.cn/image/img/20180319/927283404833.jpg http://img.yf116.cn/image/img/20180319/927563407660.jpg Based on the operational performance of the projects that are already in use, the Shenhua Ordos 1.08 million t/a direct liquefaction demonstration project has been operating continuously and stably, with a load rate of around 80%. The 180,000 t/a indirect liquefaction project shares the gasification unit with the direct liquefaction project; however, due to insufficient capacity of the gasification unit, it has not yet been put into use. It is expected that further optimizations will be made in the second and third phases of the direct liquefaction project ； The 160,000 t/a demonstration plant of Yitai and the 160,000 t/a demonstration plant of Lu’an both have the capacity to operate at full capacity, with the Yitai plant achieving good economic results ； The 1 million t/a project at Yankuang Yulin has achieved continuous, stable, and high-load commercial operation. The Shenhua Ningmei 4 million tons/year project is the world’s largest single-scale coal indirect liquefaction facility; Line A has been in trial operation for half a year, with a production load of around 50%–60% ； Line B is scheduled for trial operation in the second half of 2017. There are a total of 4 new coal-to-oil projects under the \"13th Five-Year Plan\" for the demonstration of advanced coal processing industries. As of June 2017, the construction of the first phase of the Lu’an Changzhi integrated project for the clean utilization of high-sulfur coal for oil, chemicals, electricity, and heat production, with a capacity of 1 million tons per year, was nearing completion. The 1 million tons per year indirect liquefaction project in Yitai Ili was in the process of undergoing design optimizations, while the 2 million tons per year coal indirect liquefaction project in Yitai Ordos had already seen its groundbreaking ceremony held, with design optimizations currently underway ； Some design tendering and other related work have been completed for Guizhou Yufu Bijie (Nayong) 2 million t/a coal indirect liquefaction project. The coal-to-oil reserve projects outlined in the \"13th Five-Year Plan for the Development of Advanced Coal Processing Industries\" total 3, including the follow-up project for the first phase of coal indirect liquefaction in Yulin, Shaanxi, the Yitai Ganquanbao coal indirect liquefaction project, and the second phase of Shenhua Ningxia’s coal indirect liquefaction project. The details of these projects are expected to be determined based on the progress of the preliminary projects. In addition, the Yitai Ordos 1.2 million t/a indirect liquefaction project for producing fine chemicals was put into trial operation in the first half of 2017. The status of the coal-to-oil projects under construction is shown in Table 2. http://img.yf116.cn/image/img/20180319/933113439115.jpg http://img.yf116.cn/image/img/20180319/933503443011.jpg Selection of key technologies for coal-to-oil projects; Selection of key technologies for direct coal liquefaction. The principle of direct coal liquefaction involves the use of solvents to extract components from coal, and under high temperature, high pressure, and in the presence of catalysts, hydrogenation of the coal slurry is carried out to alter the molecular structure of the complex organic compounds in coal, thereby increasing the H/C ratio and converting coal directly into liquid oil products. Direct coal liquefaction has a long history of development. Typical foreign processes include: the German IGOR process, the American HTI process, and the Japanese NEDOL process. Shenhua Group has also conducted research in the field of direct coal liquefaction for many years. Based on in-depth studies of the properties of Shenhua coal, the liquefaction process, and catalysts, it developed a direct coal liquefaction process with its own unique characteristics. This process has been validated through BSU tests (a total of 10 experiments carried out by Shenhua in collaboration with research institutions, spanning 249 days in total), PDU tests (5 scale-up experiments conducted by Shenhua in partnership with enterprises), and industrial demonstration units. The process flow for direct liquefaction is shown in Figure 1. http://img.yf116.cn/image/img/20180319/934373447766.jpg The Shenhua coal direct liquefaction project is the world’s first industrial project for coal direct liquefaction. In September 2002, the project received approval from the **National Development and Reform Commission. The first phase has a capacity of 3.2 million tons per year, with three production lines. To mitigate project risks, the first phase is implemented in stages, with the capacity of the first production line set at 1.08 million tons per year. The core units of Shenhua’s direct liquefaction project include coal liquefaction units, hydrogenation stabilization units, hydrogenation reforming units, light hydrocarbon recovery units, and hydrogen production units; in addition, there are supporting utility systems and auxiliary facilities as well. The overall process flow is shown in Figure 2. http://img.yf116.cn/image/img/20180319/935203452085.jpg The coal liquefaction unit for the first production line was originally intended to use the process technology of the American company HTI. However, this technology has issues such as an inability to operate stably over the long term, as well as a low utilization rate of the liquefaction reactor. In August 2003, Shenhua Group resolutely replaced it with a domestically developed coal direct liquefaction process technology; the catalyst used was the high-efficiency 863 coal direct liquefaction catalyst jointly developed by Shenhua Group and the China Coal Research Institute, and the fixed-bed hydrogenation process from the original HTI process was replaced with T-star hydrogenation. The key process technologies and equipment scale ultimately adopted for the first production line are shown in Table 3. http://img.yf116.cn/image/img/20180319/936123457219.jpg http://img.yf116.cn/image/img/20180319/936403460047.jpg http://img.yf116.cn/image/img/20180319/93753462519.jpg http://img.yf116.cn/image/img/20180319/940223482261.jpg Selection of key technologies for typical indirect liquefaction projects. Coal indirect liquefaction involves first gasifying coal entirely into syngas, and then using this syngas as a raw material to produce hydrocarbon fuel oils, as well as chemical raw materials and products through the Fischer-Tropsch process; alternatively, methanol can be synthesized first, and then fuel oils can be produced through the reformation and conversion of methanol. FT synthesis is the core of indirect liquefaction processes. Typical indirect liquefaction methods used both domestically and internationally include Sasol’s FT synthesis process in South Africa, Shell’s SMDS process in the Netherlands, the slurry-bed synthesis technology developed by the Shanxi Institute of Coal Chemistry under the Chinese Academy of Sciences, and Yankuang’s coal-to-oil technology. All these technologies are based on the FT synthesis method, and through improvements and optimizations in terms of processes and catalysts, they have been or are being applied in industrial-scale coal-to-oil production. The coal-to-oil process in the Fischer-Tropsch synthesis includes steps such as gasification of coal to produce syngas, catalytic synthesis of hydrocarbon products, as well as product separation and further processing. The process flow is shown in Figure 3. http://img.yf116.cn/image/img/20180319/941333489376.jpg http://img.yf116.cn/image/img/20180319/94203492057.jpg The coal indirect liquefaction projects that are currently in operation in China use the Fischer-Tropsch synthesis technology. The Yankuang Yulin project employs the low-temperature Fischer-Tropsch synthesis technology developed by Yankuang itself, while the Shenhua Ningmei Ningdong project with an annual production capacity of 4 million tons uses the medium-temperature slurry-bed Fischer-Tropsch synthesis technology provided by Zhongke Synthetic Oil Company. All other projects make use of the low-temperature Fischer-Tropsch synthesis technology offered by Zhongke Synthetic Oil Company. Regarding gasification technology, various companies have chosen advanced fluidized-bed pressurized gasification methods such as GSP coal powder pressurization, SHELL coal powder pressurization, GE coal-water slurry pressurization, and the multi-material slurry technology developed by the Northwest Research Institute, depending on the characteristics of the coal used. For purification technologies, German LURGI systems, domestically developed alternatives, and low-temperature methanol washing technology have all been employed. The selection of key technologies for typical coal indirect liquefaction projects is shown in Table 6. http://img.yf116.cn/image/img/20180319/943583503884.jpg http://img.yf116.cn/image/img/20180319/944273506780.jpg http://img.yf116.cn/image/img/20180319/944583509895.jpg http://img.yf116.cn/image/img/20180319/945363513653.jpg