Production of maleic anhydride in China

Thread Content

The industrial production of maleic anhydride in our country began in the 1950s, but its development was very slow due to limitations in reactor design and manufacturing capabilities, as well as poor catalyst performance, high consumption, severe pollution, and small-scale production facilities. It was not until the 1980s, when China introduced several 10,000-ton capacity maleic anhydride production units, that the industry for maleic anhydride production in the country began to develop on a normal track. In 1986, Tianjin Zhonghe Chemical Factory introduced technology from the American company SD to build China’s first industrial production facility for maleic anhydride using the benzene oxidation method, with a capacity of 10 kt/a ； In 1995, the Synthetic Chemical Factory in Suzhou, Jiangsu Province, introduced Langsha Company’s benzene-based fixed-bed maleic anhydride technology to build an industrial plant. In 1997, the Danyang Chemical Plant in Jiangsu Province collaborated with Italy to build a 10kt/a phthalic anhydride production facility. The successful introduction of such facilities, along with years of effort to understand and adapt the imported technology, coupled with China’s own experience in upgrading small-scale kiloton-level anhydride production units, has led to a significant improvement in China’s technical capabilities for producing anhydride. In 1996, a 6kt/a fixed-bed benzene-based maleic anhydride production plant developed and designed in China was put into operation at Qifeng Chemical Factory in Zibo, Shandong. In 1999, the domestically produced 10,000-ton/year benzene-based fixed-bed maleic anhydride plant built by Tianjin Zhonghe Chemical Factory was put into operation successfully. Based on actual production assessments, various economic indicators such as product quality and raw material consumption were essentially the same as those of the imported plants. At present, the technology for producing maleic anhydride using a benzene fixed-bed oxidation method in our country is quite mature. The process is similar to that of the AlusllisldUCB method, but distillation under azeotropic conditions with xylene is used for post-treatment. In the fixed-bed unit for producing maleic anhydride via benzene oxidation, domestic catalysts are used in combination with imported catalysts. At present, there are two units in our country that use butane to produce maleic anhydride. One of them is a 10kt/a maleic anhydride production facility built and put into operation in 1994 by the Panjin Organic Chemical Factory in Liaoning, using the fixed-bed water absorption process supplied by the American company SD. Another set is a 15 kt/a maleic anhydride production plant that was put into operation in 1996 by Shandong Dongying Shengli Oil Chemical Co., Ltd., which adopted the butane fluidized bed solvent absorption process technology from Lummus of the United States. Compared with the benzene method, due to the constraints imposed by China’s resource conditions, the development of domestic production technology for n-butane maleic anhydride has progressed relatively slowly. At present, the plant at Panjin Organic Chemical Factory is operating normally, but it relies on imported catalysts. Meanwhile, the fluidized-bed maleic anhydride plant owned by Shandong Dongying Shengli Oil Chemical Co., Ltd. has a very low operational rate for various reasons and is essentially shut down. At present, there are over 20 manufacturers of maleic anhydride in China. The total production capacity was 185 kt in 2000, rising to 234 kt in 2002, with a production volume of around 174 kt. Tianjin Zhonghe Chemical Factory is currently the largest manufacturer of maleic anhydride in China, accounting for about 20% of the country’s total maleic anhydride production. As of September 2006, the number of manufacturers of maleic anhydride and fumaric acid across the country had increased to 28, of which 9 companies produced both maleic anhydride and fumaric acid. By 2008, it is expected that another 16 units with a total production capacity of 350,000 tons will be built and put into operation, while 12 units with a total production capacity of 300,000 tons will begin construction. The main manufacturers of maleic anhydride in China in 2002 are shown in Table 1.2 on the following page. As China’s maleic anhydride production capacity continues to increase, output also keeps rising. In 1997, China’s production of maleic anhydride was only 53 kt; it increased to 140 kt in 2001 and further to 174 kt in 2002. The average annual growth rate of production from 1997 to 2002 was approximately 26.8%. China imports a certain amount of maleic anhydride each year, and this import volume is on the rise year by year, although the total import volume remains low.