Gasoline from Woody Biomass via Thermochemical Gasification, Methanol Synthesis, and Methanol-to-Gasoline Technologies: A Technoeconomic Analysis

This work describes a technoeconomic analysis of the feasibility of making gasoline using biomass-derived syngas that was completed at the National Renewable Energy Laboratory (NREL). The process includes the following steps: (1) biomass gasification of woody residues, which produces a syngas rich in hydrogen and carbon monoxide; (2) syngas cleanup by means of tar reforming and scrubbing, followed by the removal of acid gases; (3) synthesis of methanol from clean syngas by passing it over a copper/zinc oxide/alumina catalyst; (4) conversion of methanol to gasoline using a ZSM-5 zeolite catalyst, first developed by Exxon Mobil as the methanol-to-gasoline (MTG) technology; and (5) multiple gasoline separation and finishing processes. The process was modeled in Aspen Plus, and information taken from the Aspen Plus simulation was used to complete a discounted cash flow rate of return (DCFROR) analysis. The results of the DCFROR, using a poplar wood feedstock cost of $55.89/dry metric tonne ($50.70/dry U.S. ton), give an estimated plant gate price (PGP) of $15.73/GJ ($16.60/M1'vlBtu) (2007 U.S. dollars) for gasoline and LPG (liquefied petroleum gas). The corresponding unit prices for gasoline and LPG are $0.52/L ($1.95/gal) and $0.40/L ($1.53/gal), respectively, with yields of 229.9 L of gasoline and 38.8 L of LPG per metric tonne of dry biomass (55.1 gal of gasoline and 9.3 gal of LPG per short ton of dry biomass). This report is a future look at the potential of the biomass-to-gasoline process, based on calculations for an nth plant and 2012 technology targets for clean syngas from biomass as established in the Multi-Year Program Plan of the U.S. Department of Energy (DOE) Office of the Biomass Program.