【Ten Years of Rapid Development in Chemical Engineering Equipment】The “Saiding Furnace Low-Rank Coal 4.0 MPa Gasification Technology” developed from 2017 to 2022 won the Second Prize for Scientific and Technological Progress

Coal gasification technology is the cornerstone of coal chemical industry, especially in the production of coal-based natural gas; the core component of this technology is the gasifier. The SD gasifier’s pressurized coal gasification technology represents a major approach in this field, and it is an proprietary technology developed over many years as part of the key research projects undertaken by SD Engineering Co., Ltd. during the \"Seventh Five-Year Plan\" and \"Eighth Five-Year Plan\" periods. In 2007, Saiding Company was the first in China to propose and put into practice the idea of using low-rank coal as a raw material, along with Saiding-type coal crushers and pressurized gasification to produce natural gas. The main advantage of this process is its ability to utilize low-quality coal for gasification, as well as to achieve efficient gasification of coal with high moisture content (30–40%) and high ash content (over 30%), something that is difficult to accomplish with other gasification methods. In addition, this gasification technology boasts the unique advantages of high thermal efficiency and low oxygen consumption. Using low-rank coal as raw material and the Saiding furnace coal crushing pressurized gasification process to produce natural gas, the high methane content in the raw gas at the exit of the gasifier can be utilized, thereby reducing the size of subsequent purification and synthesis units, lowering investment costs, and improving energy conversion efficiency. Saiding Corporation conducted an analysis and comparison of coal-to-natural gas production with coal-to-oil, coal-to-methanol, dimethyl ether production, and coal-fired power generation in terms of investment, processing costs, transportation costs, overall thermal efficiency, conversion rates, waste heat utilization rates, and the price of thermal energy. In coal-to-natural gas projects that use Saiding’s reactors as the core technology, the CO conversion rate is close to 100%, the hydrogen conversion rate is 99%, the CO2 conversion rate is 98%, and the overall effective energy conversion rate is 60–65%. This figure is 17% higher than that of methanol production, 15–25% higher than that of oil production, and 27% higher than that of power generation. Coal-to-natural gas production using Saiding furnaces as the core overcomes the drawback of low calorific value associated with traditional coal-based gas production. It requires the least amount of water per unit of heat generated, and the wastewater resulting from methane synthesis contains almost no harmful substances, making it easy to utilize; thus, it is the most water-saving energy product.

Aiming at the product requirements and characteristics of raw coal for the **first approved coal-to-natural gas project**, SDI Company, leveraging its years of technical expertise and innovation, has successfully developed a coal crushing and pressurized gasification process using SDI furnaces with a diameter of Φ3.8m and a pressure of 4.0 MPa. This technology has been applied in projects such as Inner Mongolia Datang International Kesikteng Coal-to-Natural Gas Co., Ltd., Xinjiang Qinghua Coal-to-Natural Gas Co., Ltd., as well as other ongoing projects related to coal gas production, ammonia synthesis, and methanol production. Among them, the Datang Keqi coal-to-natural gas project has seen its gasification unit put to the test since it began operation in 2013. The gasifier design calls for 15 units in operation with 1 as a backup; in practice, 13 gasifiers are sufficient to achieve a daily production capacity of 4 million standard cubic meters of SNG. The wastewater treatment load is 95% of the designed value. The oxygen demand per gasifier can be increased from the designed value of 5232 Nm3/h to 5800 Nm3/h, allowing for a wide operating range and flexibility in adjustments. It is also possible to operate the gasifiers at high loads over extended periods – a single gasifier has been operated continuously for up to 241 days. The average online rate of the gasifiers is 93.7%, while the average service life of the vulnerable components, such as the ash lock valves, is 187 days. A production state of full capacity or even overload has been reached. The qualified natural gas produced in the first series of the Datang Keqi project was successfully integrated into Beijing’s gas distribution network on December 23, 2013, marking the successful operation of the world’s first coal pulverization pressurized gasification furnace operating at 4.0 MPa.

This technology completely overcomes the technical challenges associated with the clean and efficient gasification of low-quality lignite at an operating pressure of 4.0 MPaG. The increase in gasification pressure enhances the overall energy utilization efficiency of coal-to-natural gas projects. The successful operation of the 4.0 MPa coal pulverization pressurized gasifier demonstrates the safety, reliability, and stability of this technology, representing a significant improvement in China’s coal gasification technology level. Given that the Saiding furnace features unique counter-current bed gasification, high thermal efficiency, the production of methane with a high concentration during the gasification process, and the generation of by-products such as coal tar, phenol, and ammonia, it holds great prospects for development in the coal-to-natural gas industry and the hierarchical utilization of coal. Saiding Company has completed over 170 projects in China related to the technology of pressurized coal gasification as well as the design and general contracting of gasification units; it is also the engineering company that has implemented this pressurized coal gasification technology on the widest scale worldwide. The gasification technology using Sideng furnaces for low-rank coal at 4.0 MPa, proposed by the company, has been successfully applied in **four coal-to-natural gas projects approved by the National Development and Reform Commission, where stable high-load production has been achieved. The 4.0 MPa Saiding furnace using low-rank coal as raw material was first applied in Inner Mongolia’s Datang Keqi coal-to-natural gas project in China; subsequently, the Xintian coal-to-natural gas project in Ili was built, which is currently the largest of its kind in the world. Once the design targets are met, the Yili Xintian coal-to-natural gas project will be able to produce 2 billion cubic meters of pure natural gas per year. The project can convert 6.77 million tons of coal into 2 billion cubic meters of natural gas each year, which will be sent to Zhejiang; this amount accounts for about one-third of Zhejiang’s current natural gas consumption. The sales revenue from natural gas alone will amount to 3.366 billion yuan. In 2021, the Yili Xintian Coal-to-Natural Gas Project won the **Quality Project Gold Award**. At present, the 4.0 MPa gasification technology for low-rank coal using Saiding furnaces has been successfully applied in various large-scale coal chemical enterprises such as Yili Xintian Coal Chemical Co., Ltd. and Xinjiang Qinghua Energy Group Co., Ltd. Its operational performance, as well as investment and cost levels, are superior to those of similar technologies both domestically and internationally, resulting in significant economic, social, and environmental benefits. As the most typical representative of the fixed-bed gasification process, Saiding Furnace is the only company in China that possesses coal crushing, pressurized solid slag discharge gasification technology. The promotion and application of Saiding Furnace have driven the upgrading of manufacturing industries and mechanical and electrical equipment in China, generating significant economic and social benefits. Meanwhile, under the strategic goal of achieving carbon neutrality, Saiding Company has actively responded to this call by optimizing and upgrading this technology, as well as expanding its applications in areas such as biomass. With the rapid development of coal-to-gas conversion and new-type urbanization, the gap in natural gas supply in China will continue to widen. The “Saiding Furnace” gasification technology can not only gasify low-grade coal, but also use non-fossil energy sources as raw materials for gasification, thereby producing chemical products such as natural gas and helping to achieve the overall goals of carbon reduction, emission cutback, and carbon sequestration.

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