Techno-economic and life cycle analysis of different types of hydrolysis process for the production of p-Xylene

Abstract

The need for producing renewable chemicals and fuels from lignocellulosic biomass has increased due to economic and environment reasons. However, most of the chemicals studied to date are produced using sugars, which is readily available from biomass as their starting raw materials rather than lignocellulose, which increase the minimum selling price of produced chemicals. In this work a novel one-step saccharification (combining pretreatment and hydrolysis) process of biomass using molten salt hydrates (MSHs), an inorganic salt solution, to produce sugars and further integration of the upstream process to produce p-Xylene is investigated. We compared our one-step process with reported commercial relevant dilute acid (DA) and concentrated acid (CA) processes using detailed techno-economic analysis and life cycle analysis. The production of p-Xylene using the DA process is more costly compared to the MSH and CA processes. The cost of raw materials and utilities are the two major cost factors for the MSH process. From the life cycle analysis point of view, CA perform better than MSH process, while the DA process is less environmentally friendly mainly due to high reaction temperatures and usage of steam because of the dilute nature of the process.