Mercury Usage in Acetylene-based PVC Production to Decrease     

In recent years, more and more mercury has been exposed to the environment globally and thus, it aroused much attention of relative organizations from various countries on mercury pollution from industrial production. Small-scale gold mining and vinyl chloride monomer production based on acetylene are the top two mercury consuming sectors worldwide.
   China possesses abundant coal but meager crude oil resources. So China's production capacity of acetylene-based PVC (polyvinyl chloride) with coal as raw materials is much bigger than that with oil as raw materials. However, PVC production by acetylene process must use mercury as catalysts. China is the world's largest manufacturer of PVC, and Chinese enterprises using acetylene process usually discharge small quantities of mercury along with wastewater during their production, contributing to the mercury pollution.
   Therefore, China, in particular the Chinese acetylene-based PVC industry, plays a pivotal role in the world's mercury pollution reduction campaign.
   In mid-2009, the Ministry of Environmental Protection, China Petroleum and Chemical Industry Association, China Chlor-Alkali Industry Association, the U.S. Natural Resources Defense Council, the Chemical Registration Center of SEPA as well as dozens of domestic PVC enterprises like Xinjiang Tianye Co., Ltd., Yibin Tianyuan Group Co., Ltd., Qingdao Haijing Chemical Co., Ltd. and Hebei Shenghua Chemical Industry Co,. Ltd. met in Beijing to discuss the mercury abatement problems in China's acetylene-based PVC production, and also to develop an implementation plan together with the United Nations Environment Program (UNEP). As reported, the UNEP decides to speed up voluntary actions in addressing mercury contamination and open international negotiations, and also draft a global legally binding document on mercury reduction in 2010.
   Since the 1980s, China's chemical industry has started to pay attention to mercury discharge problems in chemical production. For example, China promulgated a regulation that only certificated companies are allowed to produce and recover mercury containing catalyst so as to reduce the discharge of mercury. At the same time, China also organized the research and development of environmentally friendly low-mercury catalyst, and made great efforts to promote technologies of controlling mercury pollution. Today, some domestic PVC manufacturers focus on the research and development of low-mercury and mercury-free catalysts in an effort to find substitutes for the existing high-mercury catalysts. Of them, companies like Xinjiang Tianye Co., Ltd., Shandong Hengtong Chemicals Co., Ltd., Shandong Haihua Company Limited, Tangshan Sanyou Chemical Industries Co., Ltd., and other dozens of companies have began to use low-mercury catalysts. At the same time, some forward-looking companies like Xinjiang Tianye Co., Ltd. are dedicated to develop mercury-free catalysts so as to eliminate mercury discharge in the production.
   However, seen from the current mercury pollution control progress, China's acetylene-based PVC companies have not yet come up to the expectations of the international community. Only less than a half of the PVC manufacturers in China are doing their utmost to study mercury-free catalysts, most of the acetylene-based PVC manufacturers still need to strengthen R&D efforts and capital investment in substitutes for high-mercury catalysts.
   In addition, mercury also plays an important role in thermometers, batteries, lightening and other areas. Coal-fired power generation is another big source of mercury pollution in China, for coal is often associated with heavy metals such as mercury. In particular, in areas like Guizhou province, the mercury content in coal is much higher than in northeastern China, Inner Mongolia and other places. Moreover, along with the implementation of the western China development strategy and the construction of west-east power transmission project, a large number of coal-fired power plants are built right in Guizhou province.
   At present, although China has launched the development of mercury removal equipments, most of the researchers are still seeking their way in mercury reduction and removal practices, because there is no large-scale commercial success experience for reference.