China National Petroleum Corp. (CNPC) (Beijing) has began construction on a USD 42 million natural gas purification plant in Wanzhou City, the economic center of the Three Gorges Reservoir area. The plant, on 5.3 hectares of land, will treat 2 million cum per day of raw natural gas to provide an annual natural gas purification capacity of 600 million cum. The plant will use methyl diethanolamine in natural gas desulfurization, triethylene glycol will be used in the dehydration process, and heat stress granules technology will be adopted for sulfur recycling.