MECS Inc. is a U.S.-based process technology and equipment supplier focused on sulfuric acid production and related emissions control. Originating as Monsanto Enviro-Chem Systems, the company is headquartered in St. Louis, Missouri, and operates as part of Elessent Clean Technologies. MECS licenses process designs and provides engineered systems for greenfield plants and revamps, as well as solutions for spent acid regeneration used by refiners and chemical producers.
Its portfolio includes sulfuric acid catalysts, heat recovery systems, corrosion‑resistant equipment (such as ZeCor alloy components), and Brink mist eliminators for acid mist control. MECS also offers plant optimization, maintenance, and technical support aimed at improving energy efficiency, reliability, and environmental performance. The company serves customers in fertilizers, metals and mining, refining, and broader chemical manufacturing, with installations and service support worldwide.