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Methanol is an important basic raw material in the organic chemical industry, and it can be used to produce various chemical products such as formaldehyde, acetic acid, methyl methacrylate (MMA), and dimethyl terephthalate (DMT). China’s methanol consumption structure is as follows: MTBE, dimethyl ether, and blended fuels account for 33%, formaldehyde accounts for 30%, acetic acid accounts for 12%, esters (including dimethyl carbonate (DMC), DMT, MMA, and methyl acrylate, etc.) account for 10%, pesticides account for 6%, and pharmaceuticals account for 6%. The structure of methanol consumption abroad is shown in Table 1. There are two processes for methanol production: the coal gasification process and the natural gas-to-methanol process. In Europe and the United States, methane is primarily produced using natural gas as a raw material. This process offers the advantages of low investment costs and no pollution, and there is no need to worry much about finding markets for by-products. However, our country lacks cheap natural gas resources, while coal reserves are relatively abundant; therefore, most of the methanol production capacity comes from coal gasification processes. 1 Coal gasification There are mainly 4 techniques for producing syngas from coal as raw material: Dexaco water-coal slurry gasification, Sherwood powder coal gasification, Lurgi pulverized coal gasification, and UGI atmospheric pressure gasification. UGI’s atmospheric gasification technology is mature and reliable, but it requires the use of smokeless lump coal; it also has drawbacks such as limited design capacity and high emissions of waste gases, which prevent it from meeting the needs of large-scale production. Although Lurgi gasification technology is mature and large-scale units of this type are already in operation in China, its biggest drawback is the low gasification temperature. The harmful substances generated, such as tar and wastewater, are difficult to treat, resulting in high pollution levels. The utilization rate of raw materials is low, and the methane content in the crude syngas is high; therefore, it is only suitable for use as city gas and not as a suitable source of syngas. The Shell Coal Gasification Process (SCGP) is one of the most advanced coal gasification technologies in the world today, achieving new levels in terms of safety, efficiency, and environmental protection. The high-quality gas produced by this process can be used as a feed gas for ammonia and methanol synthesis. The service life of the water wall is 25 years, while the design life of the nozzles is 1 year. However, since dry powder is used as the feed, the gasification pressure cannot be too high, which makes operation somewhat difficult. Pressurized gasification of water-coal slurry was successfully developed by Texaco in the United States in the 1970s, and the first large-scale pilot commercial plant was built in the early 1980s; it is now being successfully applied in China. In addition to high oxygen consumption, this technology has the following characteristics: (1) A single furnace can process a large amount of coal, resulting in high production capacity ； (2) It features high gasification pressure and low power consumption, as well as a high content of useful gases (CO+H2), making it suitable for use as syngas ； (3) Good suitability of raw materials and high utilization rate ； (4) Less waste generation ； (5) Large number of users, high rate of domestic equipment usage. The biggest drawback of the Texaco process is the short lifespan of the burners, which is only 45 days, and the refractory bricks need to be replaced annually, with a replacement period of 45 days as well. Taking a 300,000 t/a methanol plant as an example, the investment in gasification process equipment is approximately 1.556 billion yuan, as detailed in Table 2. In addition to methanol, coal gasification processes can produce various by-products, making them suitable for being located near power plants or chemical plants. Still taking the 300,000 t/a plant as an example, the estimated methanol production cost is shown in Table 3. The raw material prices in Table 3 are based on recent market prices in China. Since last year, coal prices have been rising continuously, resulting in **higher production costs for methanol compared to previous years. In 2003, when the coal price was 250 yuan per ton, the production cost of methanol was only around 1,000 yuan per ton. Note: ① The unit for electricity consumption is kW h per ton of methanol, while the price is expressed in yuan per kW h. 2 Methanol production from natural gas – Europe and the United States have abundant natural gas resources, and methanol is primarily produced using natural gas as a raw material. For example, 96% of the methanol production capacity in the United States comes from natural gas processes. ICI and LuChi are the main suppliers of technology for producing methanol from natural gas using low-pressure methods. The methanol plants of Air Products and Chemicals Inc. and Celanese in Clear Lake, Texas, as well as Lyondell’s methanol facility, use ICI’s technology. Beaumont Methanol Company, Celanese’s methanol plant in Bishop, Texas, Gulf Chemical, Eastman Chemical, Enron Methanol Company, and Millennium Petrochemical use LuChi’s technology. Only Terra Industries uses Haldor-Topsoe’s low-pressure technology. The investment costs for the three technologies are shown in Table 4, while the comparison of methanol production costs is provided in Table 5. Note: Based on the construction of a 2,500 t/d methanol plant in the United States. ①10% × Investment within the factory premises ； ②25%×(Investment within the plant + Costs for equipment not part of the plan) ③ 25%×(Utilities). As can be seen from Table 5, the production cost of methanol is greatly influenced by the scale of the plant; the larger the scale of the plant, the lower its production costs. For plants of the same scale, ICI has the lowest production cost, followed by Haldor-Topsoe, with the Ruchi process having the highest cost. The main reason for the lower cost of ICI is that the investment cost for the reactor is **lower than that in the Ruchi process. As can be seen from Table 3, although the costs of the supports and heat exchange devices are slightly higher than those in the Ruchi process, the cost of the reactor is only half of that in the Ruchi process, while the cost of the heating furnace is only 15% of that in the Ruchi process. All three processes are two-stage methods: first, syngas is produced from natural gas, and then methanol is synthesized. The yields vary by little, within 5%. The investment cost for natural gas-based processes is relatively low; a 300,000 t/a methanol plant requires only 400 million yuan, which is 1/4 of the cost associated with coal gasification processes. The estimated production costs for methanol are shown in Tables 6 and 7. It can be seen that the advantages of using natural gas to produce methanol become evident when coal prices are currently high, with production costs being about 50 yuan per ton lower than those of the coal gasification process. Currently, the market price of methanol is around 2,500 yuan per ton, with profit margins in the methanol industry reaching as high as 40%. However, the volatile nature of energy prices is not entirely due to market forces, and it remains to be seen whether the large number of methanol production facilities that have come online recently will be able to catch up with the opportunities for high profits. Note: ① The unit of consumption for natural gas and nitrogen is m3 per ton of methanol, while the price is in yuan per m3 ； ②The power consumption is expressed in kW h per ton of methanol, while the price is given in yuan per kW h ； ③Unless otherwise specified, the unit of material consumption is t/t methanol ； ④Unless otherwise specified, the price is in yuan per ton.