Sustainable\nStyrene Production through Chemical Looping\nOxidative Dehydrogenation: An Experimentally Informed Technoeconomic\nStudy

Styrene is an important and growing commodity chemical\nfeedstock\nfor rubber and plastic products. State-of-the-art catalytic dehydrogenation\n(DH) of ethylbenzene suffers from high energy consumption and equilibrium\nlimitations, resulting in a substantial carbon footprint. We recently\nreported a chemical looping oxidative dehydrogenation (CL-ODH) approach\nthat offers enhanced product yields and the potential for lower emissions.\nBuilding upon experimental results obtained under industrially compatible\nconditions, this research conducts a comprehensive technoeconomic\ncomparison between CL-ODH and the commercial DH process. We modeled\nand analyzed both process schemes to determine energy consumption,\nCO<sub>2</sub> emissions, capital cost, operating cost, and estimated\ngross margin. Sensitivity analyses were performed on critical performance\nparameters of CL-ODH, namely, single-pass conversion, selective hydrogen\ncombustion (SHC), and steam-to-ethylbenzene ratio (S/E). The sensitivity\nanalyses confirmed the potential advantage of CL-ODH versus state-of-the-art\ntechniques, even with conservative catalyst performance assumptions.\nThe comprehensive technoeconomic analysis revealed that the base-case\nCL-ODH scheme reduces energy consumption by 40% while lowering CO<sub>2</sub> emissions by 40%. Additionally, we estimate a 122% increase\nin the gross margin. With more optimistic assumptions and further\ncatalyst optimizations, up to an 87% decrease in energy consumption\ncan potentially be achieved. Our findings demonstrate that CL-ODH\ntechnology meets the “practical minimum energy consumption”\nfor styrene production published by the United States Department of\nEnergy (USDOE).