Green chemical engineering is regarded as one of the most efficient means of achieving sustainable development in chemical industries. Better and more environmentally friendly products and processes can be obtained with improvements in green product/process engineering, which mainly relies on the precise control of chemical changes and physical processes at the molecular level—that is, on molecular chemical engineering. This photograph was taken from the Wanhua Chemical Co., Ltd., in Ningbo, China, and shows an example of the industrial application of green chemical engineering technologies. Utilizing high-gravity technology based on the rotating packed-bed (RPB) reactor (developed by the Beijing University of Chemical Technology) to intensify molecular mixing, along with phosgene technology integration, Wanhua built the world’s largest diphenylmethane diisocyanate (MDI) industrial production line in 2010. This line produces better quality with less consumption, allowing Wanhua to maintain the highest market occupancy in the domestic market and to export to international markets.