Membrane Contactor Applied for Acrylic Acid Removal from Acrylate Downstream Processing: An Environmental Techno-Economic Assessment

In acrylates industry, the conventional acrylic acid (AA) removal process using a water washing tower is costly by consuming a large amount of water. To replace the traditional water washing tower for acrylates production, a TiO₂ ceramic membrane contactor to extract AA is studied. An environmental techno-economic assessment (ETEA) is performed for the acrylate production process with a membrane contactor, and its results are benchmarked with those of the traditional process in this study. A model acrylate, 2-ethylhexyl acrylate (2-EHA) is taken as the product in the assessment. Our analysis is supported by novel experimental evidence, where we found a mass transfer coefficient of acrylic acid (0.003 m³/m²h) as the speed at which the membrane allows transferring acrylic acid from an acrylate esterification solution. We consider the full production process from 2-EHA esterification to purification, with a higher resolution for the downstream processing. A manufacturing scale of 20,000 ton/year is assumed. We find that the membrane process has a slightly higher manufacturing cost (€1,643/ton 2-EHA) compared to the water washing process (€1,629/ton 2-EHA), due to the high membrane cost of €25/ton 2-EHA. However, the membrane process has €20/ton 2-EHA lower cost from energy consumption and other operating cost, because 30% less water is demanded by the membrane contactor. The lower water consumption also results in a lower environmental impact than the water washing process, as indicated by scores of the 18 midpoint categories. The manufacturing cost of the membrane process will be lower than the water washing process when increasing the mass transfer coefficient to 0.005 m³/m²h.