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Process, coal gasification, review: A brief overview of several coal gasification processes. There are currently many mature or relatively mature pressurized coal gasification processes available in China, and there is a wealth of literature and materials available for a comparative analysis of these various processes. Here, only the characteristics of some of the main coal gasification processes and the problems existing at present are briefly discussed. 1. TEXACO water-coal slurry gasification: This process uses water-coal slurry as the feed material, liquid slag as the by-product, and pressure gasification in a fluidized bed; the water-coal slurry reacts with pure oxygen under high temperature and pressure to produce gas. The main structure of the gasification furnace is a single-nozzle bottom-fed type for water-coal slurry; most of them employ a water cooling process. The maximum capacity of a single furnace can currently reach 2,000 tons of coal per day. The operating pressure is usually 4 MPa or 6.5 MPa, with a few projects achieving 8.4 MPa as well. The first plant in our country to adopt this technology was Shandong Lunan Fertilizer Factory, which began operations in 1993; subsequently, several other plants adopted it as well, and currently there are about a dozen such plants. Representative examples include the Wei River (gasification pressure of 6.0 MPa), Huainan (gasification pressure of 4.0 MPa), and southern Shandong (gasification pressure of 2.0 MPa). Since China has fully mastered the TEXACO gasification process and accumulated extensive experience in this area, the equipment manufacturing, installation, and project implementation take less time. There is also rich experience in operating such facilities, which means that it takes a relatively short time to reach the desired performance levels. The main issues are the need for a certain selection of coal quality, as well as relatively low gasification efficiency, higher oxygen consumption, and a short lifespan of the refractory bricks. However, as these facilities have been in operation in China for longer periods of time, some of these problems have been effectively resolved. 2. Multi-nozzle opposed water-coal slurry gasification: This technology was developed during the Ninth Five-Year Plan period through collaboration between East China University of Science and Technology, Yankuang Lunan Fertilizer Plant, and China Tianchen Chemical Engineering Company. It passed the appraisal and acceptance organized by the former **Petroleum and Chemical Industry Bureau in October 2000. The demonstration plant is Yankuang Guotai Chemical Co., Ltd., which has built two gasification units capable of processing 1,150 tons of coal per day; the operating pressure is 4.0 MPa. These units produce 240,000 tons of methanol per year, while also generating 71.8 MW of electricity as a by-product. The device was put into operation in October 2005. The second project is the application in the domestic production project for large-scale nitrogen fertilizers at Hualu Hengsheng Chemical Co., Ltd., where a multi-nozzle opposed water-coal slurry gasification unit was installed, capable of processing 750 tons of coal per day at an operating pressure of 6.5 MPa; this unit came online at the beginning of June 2005. This process still falls under the category of water-coal slurry gasification. The main difference from TEXACO’s approach is that it uses opposed multi-nozzles instead of a single nozzle used by TEXACO, which enhances heat and mass transfer and results in better gasification performance. However, multiple nozzles require multiple control systems, which increases the equipment costs and the amount of maintenance work needed. Since it is domestic technology, the costs associated with process packages and proprietary technology licenses are significantly lower compared to imported technologies. 3. SHELL powder gasification: The main structure of the gasifier consists of dry coal powder fed through multiple nozzles for upward flow gasification in a waste heat boiler; a cold furnace wall is used, and cold gas is returned to the furnace to cool the hot gas. Gas cooling is carried out using a waste heat boiler system. Due to the outstanding technical advantages of Shell’s gasification technology, it has attracted a number of domestic companies to adopt it, with over a dozen such companies at present. The biggest drawback of this process is the high investment cost, with extremely expensive equipment ； Using a waste heat exchanger for syngas heat exchange increases costs; for chemical processes that require steam, direct water cooling is a more reasonable approach ； High power consumption is required for drying, coal grinding, high-pressure nitrogen, and pressurizing the syngas used for quenching in the furnace, among other things. Currently, five units that are in operation within China include Hubei Shuanghuan, three Sinopec units (Hubei Fertilizer, Anqing Petrochemical, and Yueyang Petrochemical), and Liuhua. 4. Xi’an Thermal Power Institute’s two-stage dry coal powder pressurized gasification technology: the gasifier features a water-cooled furnace chamber and liquid slag discharge. During operation, pulverized coal, water vapor, and oxygen are injected into the lower furnace, while a small amount of pulverized coal and water vapor are injected into the upper furnace. The sensible heat of the gas in the lower furnace is utilized to drive the pyrolysis and gasification reactions of the coal in the upper furnace, 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; this eliminates the need for a cold gas quenching process. This gasification furnace has been granted a **patent**. There are currently no industrial plants operating using this technology, but a 2,000 tons/day two-stage dry coal powder pressurized gasification furnace (waste boiler process) has been applied in Huaneng Group’s “green coal power” project, with completion expected in 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., with operation expected to begin in 2008. 5. HT-L gasification technology: This technology was developed by the Beijing Aerospace Power Research Institute of China National Space Administration. The design of its gasification furnace combines the advantages of SHELL and TEXACO, and demonstration projects are currently being carried out, including those conducted by Anhui Linquan Chemical Co., Ltd. and Puyang Longyu Chemical. 6. Multi-component Slurry Gasification Process of the Northwest Research Institute of Chemical Industry: The Multi-component Slurry Gasification technology (MCSG) is a large-scale coal gasification technology developed by the Northwest Research Institute of Chemical Industry. This technology utilizes the concept of wet gasized fluidized bed gasification; carbon-containing materials such as coal, petroleum coke, and petroleum asphalt, along with oils (crude oil, heavy oil, residue oil, etc.) and water, are optimally mixed to form a multi-component slurry. When this slurry is mixed with oxygen through nozzles, it is instantly gasified. This technology features wide adaptability to different feedstocks, advanced gasification parameters, maturity and reliability, and low investment costs. To date, three industrial units using this technology are in stable operation in China. 7. GSP gasification technology: The main structure of the gasifier in this technology is a single-nozzle bottom-fed pressurized dry coal powder fluidized bed gasification system; depending on the intended use of the gas produced, direct water quenching can be employed, as in the case of users who require chemical synthesis gas. Heat can also be recovered from waste boilers to generate high-pressure steam; this is the case for IGCC power generation users. The GSP gasification technology is owned by the German Siemens Group. The main problem with the GSP gasification technology is its shortcomings in terms of single-furnace capacity and long-term operational performance. The units that have been put into operation so far have a single-furnace capacity of only 720 tons of lignite per day, and their operating time records are not very long either.