Houston-based Synthesis Energy Systems , Inc. will announce a $105 million deal on Wednesday to help build three plants in China that turn coal into synthetic gas. The deal for the U.S. chemical firm underscores the growing market in coal gasification as China looks to reduce carbon emissions while satisfying its voracious appetite for energy. China and the U.S. last month agreed to new limits on carbon emissions, starting in 2025. Looking to deploy its seemingly infinite reserves of coal, China has been encouraging its state-backed companies to forge partnerships with Western chemicals companies. It aims to increase its production of synthetic gas from coal to around 10% by 2020 from almost nothing a few years ago. There are currently 118 gasification plants in China, and another 60 under construction, according to an Energy Department database.