SK Engineering & Construction Co., one of South Korea\'s leading builders, said Monday that it and its Thai partner have won a US$100 million order to expand a chemical plant in Thailand. SK E&C said it plans to complete the project in Thailand\'s Map Ta Phut industrial complex by 2015 under a deal with PTT Global Chemical Pcl, Thailand\'s biggest petrochemical company. The project calls for SK E&C and PTT Maintenance and Engineering Co., a subsidiary of PTT Global Chemical, to boost annual production of paraxylene and benzene by 120,000 tons and 50,000 tons, respectively. K E&C said it holds a 45 percent stake in the project, while PTT Maintenance and Engineering holds the rest. SK E&C is an unlisted construction arm of SK Group, South Korea\'s third-largest conglomerate