(659c) Techno-Economic and Life Cycle Analysis for the Production of Renewable Acrylonitrile from Non-Food Biomass

The industrial sector anticipates an 11-18% annual increase in the market for carbon fiber, specifically driven by the motivation to reduce weight for vehicles. Currently, the highest performance carbon fibers are produced by heat treatment or controlled pyrolysis of polyacrylonitrile (PAN). The precursor acrylonitrile (ACN) monomer is currently produced via ammoxidation of propylene, a high volume commodity chemical subject to the volatility of the petrochemical market. Propylene accounts for approximately 70% of the total ACN production cost. The goal of this work is to develop a cost-effective, low environmental impact process for production of ACN from biomass-derived sugars, such that the ACN meets all chemical specifications of and is a direct replacement for conventional propylene-based ACN.

Southern Research (SR) has developed the biomass to ACN (B2ACN) process under a cooperative agreement with the Department of Energy during Phase I. The process is currently being designed for Phase II pilot studies at a scale of kg/hr. Briefly, B2ACN is a multi-step catalytic process for the conversion of sugars from non-food biomass to ACN at mild conditions. The process utilizes known pretreatment methods for recovery of sugars from any type of biomass. In the first reaction step, sugars are converted to glycols/glycerol using a novel multi-functional catalyst. After desired separation, glycerol is then converted to a gas phase intermediate acrolein in the second reaction step, which is followed by ammoxidation of acrolein to acrylonitrile in the final reaction step. Critical performance attributes of the acrylonitrile product are compared to a propylene-derived standard for production readiness in the PAN and carbon fiber processes. The process has been optimized for heat recovery and separations. Phase I experimental results and initial estimates show a significant reduction in greenhouse gas (GHG) emissions of up to ~37% and cost reduction of up to ~15-22% compared to propylene-derived ACN. This paper will discuss the techno-economic and lifecycle impact on the production of ACN with respect to key variables, including feed materials, impurity/by-product separations, catalysts, utilities, water utilization, and green field capital expenditures tailored to downstream applications. The motivation of this study is to provide a guide to end consumers and brand owners to realize the potentials and pitfalls of the process for further improvements and adoption.