Design and Techno-Economic Feasibility of a Sustainable Styrene Production Plant Integrating Corn Stover-Derived Bioethanol

This paper presents a comprehensive design, implementation, and feasibility analysis of a sustainable styrene production plant that integrates conventional ethylbenzene dehydrogenation with bio-based feedstock processing. Located on the Gujarat coastline, India, the proposed facility is designed to produce 220,000 tonnes per year of styrene while addressing environmental, social, and economic sustainability objectives. Agricultural corn stover sourced from local farms is valorised via pretreatment, enzymatic hydrolysis, and two-phase simultaneous saccharification and fermentation (TPSSF), achieving ethanol yields of up to 477 kg per tonne of biomass. Bioethanol is subsequently alkylated with benzene over a beta-zeolite catalyst, delivering a 95% conversion with respect to bioethanol and 85.8% selectivity to ethylbenzene. This intermediate is then dehydrogenated at 550 °C using a potassium-promoted iron oxide catalyst to produce styrene with a 96.2% selectivity. Extensive heat integration, benzene recycling, and a steam-to-ethylbenzene ratio of 7:1 enhance energy efficiency and process robustness. Techno-economic analysis demonstrates that the plant remains commercially viable and profitable despite the incorporation of renewable feedstocks. The utilisation of corn stover reduces biomass waste and greenhouse gas emissions, lowers dependence on fossil resources, and supports local employment and supply chains. By embedding sustainability, safety, process integration, and economic assessment within a unified design framework, this work provides an industry-relevant and transferable model for low-carbon styrene manufacture aligned with UN Sustainable Development Goals 7, 12 and 13.