Warrendale, PA - The Sinopec Maoming Company selected Siemens (formerly USFilter) to supply a wet air oxidation (WAO) system for the treatment of spent caustic. The system, designed by Siemens Zimpro Products will be installed at Sinopec's new ethylene facility being constructed in Maoming, Guangdong Province, in the People's Republic of China.
Using WAO technology will help Sinopec alleviate two problems frequently associated with ethylene spent caustic: disposal and odor. The technology destroys odorous sulfides and allows acid neutralization of the spent caustic, and discharge to conventional biological treatment.
"WAO is state-of-the-art technology for treating ethylene spent caustic," said Hans Werner Linne, head of I&S in China. "Sinopec has realized the benefits of using the technology at its new, world-class ethylene facility, and we're proud to help make their operations more economical and efficient."
Wet oxidation is the oxidation of soluble or suspended components in an aqueous environment using oxygen as the oxidizing agent. When air is used as the source of oxygen the process is referred to as wet air oxidation (WAO).
A common industrial application for wet air oxidation is treatment of spent caustic wastewater streams generated by ethylene plants and refineries. The process is used for complete oxidation of reduced sulfur species such as sulfides and mercaptides. By increasing temperature and pressure, complex organic contaminants such as phenols can also be broken down to either carbon dioxide and water, or biodegradable organics. By applying wet air oxidation, odor issues can be eliminated and the treated spent caustic is suitable for discharge to a conventional biological treatment process.
Wet air oxidation, developed and commercialized by Zimpro, is widely used to treat both refinery and ethylene spent caustic. In recent years, the company has supplied more than 25 wet oxidation systems for spent caustic treatment.
This latest system is the third Zimpro wet air oxidation system installed in mainland China. Fujian Petrochemical Company, Ltd., Xiacuo, Fujian, China; and the Shanghai Ethylene Cracker Complex in Shanghai, China also use Zimpro wet air oxidation systems.