Evaluation of two acrylic acid production processes from renewable crude glycerol: Rigorous process design, techno-economic evaluation, and life cycle assessment

Abstract

This study aims to propose and evaluate two acrylic acid (AA) production processes that utilize bio-based crude glycerol as a feedstock. Scheme 1 employs acrolein as an intermediate, while Scheme 2 utilizes allyl alcohol as an intermediate. For process intensification, Scheme 1 employs a one-pot reactor configuration that couples the glycerol dehydration and oxidation reactions and uses an additional reactor to suppress the formation of side products. Scheme 2 implements a membrane that helps prevent the multiple azeotropic distillation between water and other substances. Furthermore, both processes were systematically optimized based on varying levels of information available in the process (i.e., three objectives for Scheme 1, single objective for Scheme 2). From a techno-economic evaluation, Scheme 2 (2.136 USD/kg) slightly outperforms Scheme 1 (2.514 USD/kg) in terms of the minimum required selling price (MRSP). Both values are significantly higher than the market price (1.24–1.32 USD/kg) based on the conventional process that uses propene as a feedstock. Subsequently, a cradle-to-gate life cycle assessment was conducted to compare these processes across five impact categories (i.e., global warming potential, fossil source scarcity, human non-carcinogenic toxicity, water consumption, and terrestrial acidification). We have observed that Scheme 1 can be more sustainable than Scheme 2 and the conventional process if the issue associated with the acrolein left in the wastewater can be addressed. In contrast, Scheme 2 is far from environmentally friendly even compared to the conventional process, primarily because of the use of formic acid as a co-reactant.