Two-stage dry powder pressurized gasification technology

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Dry coal powder pressurized gasification technology 1. Introduction to coal gasification technology: With the support of the 863 Program, Xi’an Thermal Engineering Research Institute Co., Ltd. has, through over 10 years of research, developed a two-stage dry coal powder pressurized gasification technology. The gasifier features a water-cooled furnace chamber and liquid slag discharge. During operation, pulverized coal, steam, and oxygen are injected into the lower furnace, while a small amount of pulverized coal and steam are injected into the upper furnace. Utilize the sensible heat of the gas in the lower furnace chamber to drive the pyrolysis and gasification reactions of the coal in the upper furnace chamber, thereby improving the overall cold gas efficiency ； It also significantly reduces the temperature of the hot gas, lowering the gas at the furnace outlet below the ash melting point, thereby eliminating the need for a cold gas quenching process. Structure of the two-stage dry coal powder pressurized gasification furnace is shown below. This gasification furnace has obtained a **patent**. Schematic diagram of the two-stage dry coal powder pressurized gasification furnace; Patent certificate for the two-stage dry coal powder pressurized gasification furnace. 2. Technical features and advantages: • Gasification temperature range of 1300–1700°C, gasification reaction pressure of 0.5–4.0 MPa; carbon conversion rate of over 99%, with effective gas composition (CO+H2) reaching over 90%. It does not produce condensates such as tar and phenol, does not pollute the environment, and yields syngas of high quality ； • It has good adaptability to different types of coal; it can gasify lignite, bituminous coal, subbituminous coal, anthracite, as well as coal with high ash content and high ash fusion point, and operates in a stable and reliable manner ； • The gasification furnace features a water-cooled wall structure that uses slag to resist slag; it has no refractory brick lining, requiring minimal maintenance and no need for a backup furnace. The water wall has a service life of up to 20 years, while the burners have a service life of up to 10 years ； • Compared with advanced foreign dry gasification technologies, it achieves a 2–3 percentage point increase in cold gas efficiency and a 10–15% reduction in oxygen consumption ； Compared with water-coal slurry gasification technology, the efficiency of cold coal gas increases by 7–10%, while oxygen consumption is reduced by 20%–30% ； • The cold gas circulation cooling process can be omitted, which significantly reduces the system’s self-power consumption; at the same time, the size of the equipment in the gas cooler and purification systems is reduced by 1/2 ； • A two-stage dry coal powder gasifier can be equipped with a quenching process suitable for the chemical industry and a waste boiler process suitable for the power industry ； • The gasification system is entirely domestically produced, resulting in a cost that is about 40% lower than that of advanced foreign dry gasification furnaces. 3. History of technological development • In the 1990s, the concept of two-stage dry coal powder pressurized gasification technology was proposed ； • In 1995, a simulation method for the gasification process based on ASPEN PLUS (a chemical process design platform) was developed, and a simulation study was conducted on the performance of two-stage dry coal powder pressurized gasification ； Temperature field in a two-stage gasifier simulated by computer • In 1997, a test facility for pressurized dense-phase transportation and gasification of dry coal powder was built, with a coal processing capacity of 0.7–1.0 t/d; this facility was used to conduct research on the pressurized gasification of dry coal powder using 14 typical Chinese thermal coal types. Dry coal powder concentrated transport and gasification test facility of 0.7～1.0 t/d • In 2004, a pilot-scale dry coal powder pressurized gasification facility capable of handling 36～40 t/d of coal (10 MWth) was built. 36–40 t/h two-stage dry coal powder pressurized gasification pilot plant • In 2006, an industrial dry coal powder pressurized gasification plant with a capacity of 1,000–2,000 t/d was successfully developed. 4. Technical specifications of gasification: The two-stage dry coal powder pressurized semi-industrial plant with a capacity of 36–40 tons per day, which was developed as part of the **863 key project – “Dry Coal Powder Pressurized Gasification Technology”**, has passed 168 hours of continuous operation tests. It has now operated for over 2,200 hours in total, achieving the following technical specifications: • Carbon conversion rate ≥ 98% • Specific oxygen consumption: 300 Nm3 O2/1000 Nm3 (CO+H2) • Specific coal consumption: 520 kg/1000 Nm3 (CO+H2) • Cold gas efficiency ≥ 83% • Effective gas composition (CO+H2) ≥ 91% Composition of syngas from typical coal types Coal type Lignite Bituminous coal Sub-bituminous coal Anthracite CO (%) 61.9 62.38 62.36 69.93 H2 (%) 27.84 29.36 28.98 21.78 CH4 (%) 0.05 0.26 0.14 0 CO2 (%) 3.59 2.76 4.29 4.52 H2S+COS (%) 0.11 0.37 0.24 0.14 N2 (%) 6.51 4.87 3.99 3.61 Comparison with syngas composition specifications of major imported gasification units Coal gas composition Foreign wet gasification Foreign dry gasification Two-stage gasifier CO (%) 39.35 63.5 62.38 H2 (%) 30.78 26.50 29.36 CH4 (%) 11.43 1.60 0.26 CO2 (%) 16.43 1.90 2.76 H2S+COS (%) 0.04 0.02 0.37 N2 (%) 0.49 5.00 4.87 The types of coal that can be used for gasification include lignite, bituminous coal, sub-bituminous coal, and anthracite ； The moisture content range for coal suitable for gasification is 4%–35%. The ash content range for such coal is 5%–31%. The ash fusion point range is 1200°C–>1500°C. Control room for 36–40 t/d semi-industrial plants; flare system for 36–40 t/d semi-industrial plants; DCS control system for 36–40 t/d semi-industrial plants. Trends in cold gas efficiency and syngas composition as a function of the two-stage coal feeding ratio. 5. Engineering applications: • A 2000 tons/day two-stage dry coal powder pressurized gasification furnace (waste heat recovery system) has been applied in Huaneng Group’s “Green Coal Power” project, with completion scheduled for 2009. • A 1,000-ton/day two-stage dry coal powder pressurized gasification furnace (quenching process) has been applied to the 300,000-ton-per-year methanol production project of Inner Mongolia Shilin Chemical Co., Ltd., and is set to come online in 2008 ； 6. Green Coal Power Demonstration Projects of China Huaneng Group
• Support for major scientific research projects in recent years:
– “Feasibility Study on Integrated Gasification Combined Cycle (IGCC) Power Generation Demonstration Project”, part of the “Eighth Five-Year Plan” for scientific and technological research, 1993–1996;
– Key scientific and technological project of the power company: “Evaluation Equipment for Pressurized Gasification of Dry Coal Powder and Research on the Characteristics of Coal Gasification”, 1996–2000;
– Topic under the “Ninth Five-Year Plan” for key scientific and technological research: “Research and Development of High-Temperature Dust Removal Processes and Equipment for Coal Gas”, 1997–2000;
– Major basic research and development project: “Coal Pyrolysis, Gasification, and High-Temperature Purification”, 1999–2004;
– Key international cooperation project: “Research and Development of Pressurized Gasification Technology for Dry Coal Powder”, a collaboration between China’s Ministry of Science and Technology and the UK’s DTI, TPRI-Imperial College, 2000–2002;
– “Tenth Five-Year Plan” 863 Project: “Pressurized Gasification Technology for Dry Coal Powder” (pilot phase), 2001–2002;
– “Tenth Five-Year Plan” 863 Project: “Research and Development of High-Temperature Dust Removal Technology Using Electrostatically Enhanced Moving Particle Layer Filtration”, 2002–2004;
– Key “Tenth Five-Year Plan” 863 Project: “Pressurized Gasification Technology for Dry Coal Powder” (pilot-scale testing), 2002–2005;
– Shaanxi Province’s scientific and technological planning project: “Pilot-Scale Research Technology for Pressurized Gasification of Dry Coal Powder”, 2003–2005;
– 973 Project: “Research on the Flow, Phase Transformation, and Heat Transfer of High-Viscosity Coal Ash Slag”, 2004–2009;
– Key “Tenth Five-Year Plan” 863 Project: “Pilot-Scale Research on Pressurized Gasification Technology for Dry Coal Powder” (follow-up phase), 2005–2006;
– Major “Eleventh Five-Year Plan” 863 Project: “Research and Development of Pressurized Gasification Technology for Dry Coal Powder at a Capacity of 1,000 tons per day”, 2006–2009.

7. Contact Information
Technical Director: Xu Shisen
Phone/Fax: 029－82102309
Email: xushisen@tpri.com.cn
Technical Contact: Xu Yue
Phone/Fax: 029－82102308
Email: xuyue@tpri.com.cn
Technical Contact: Ren Yongqiang
Phone/Fax: 029－82102521
Email: renyongqiang@tpri.com.cn
Address: Xi’an Thermal Engineering Research Institute Co., Ltd., Green Coal Power Department, 710032
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