On Nov 12, a pilot unit that produces vinyl chloride through mercury-free catalysts was successfully put into operation. The unit was jointly developed by ChemChina’s Dezhou Shihua Chemical and Shanghai Advanced Research Institute of the CAS. It has a capacity of 2,000-5,000 tons and is a new technology for vinyl chloride production.
“Now that the unit is a success, we plan to produce 200,000 tons of vinyl chloride in Dezhou Shihua, and then promote the technology nationwide,” said Jiang Zhenghui, general manager of Dezhou Shihua. The rapid development of the project has brought a ray of hope to the PVC industry, he said.
A project test has passed expert reviews. Reactor temperature control, dichloroethane recovery and other key links were improved since the unit began operations at the end of August. It has been running steadily since. The new technology enables a productivity rate of more than 95 percent, featuring good product quality and high vinyl chloride content. The product is low in impurities and water and can directly go into rectification.
The technology has been named a key project in the national 973 and 863 programs. It uses acetylene and dichloroethane to synthesize vinyl chloride without mercury, creating an energy-conserving and environmentally-friendly method for PVC production. It not only eliminates mercury pollution, but also cuts raw material carbide use in half, saving 70 kilograms of standard coal per ton of PVC resin, or 1,000 yuan ($164.70) in costs.
Cutting the input of mercury in PVC production using the carbide method has become critical. Heads of the Ministry of Environmental Protection and the Ministry of Industry and Information Technology have visited Dezhou Shihua regarding the project, hoping to industrialize the technology to benefit society. Experts from the Asian Development Bank also came to the company to study the project, establishing plans to offer preferential loans to the green project.
For years, mercury-containing catalysts were added to PVC production using the carbide method, according to Zhang Wenlei, secretary-general of the China Chlor-Alkali Industry Association. The industry contributed to 60 percent of mercury use nationwide, which made China one of the biggest mercury producers and consumers around the world. On Oct 10, representatives from China and 91 other countries and regions signed the Minamata Convention on Mercury, which aims to cut mercury use by 50 percent per unit of PVC by 2020.