Gasoline from Coal and/or Biomass with CO₂ Capture and Storage. 1. Process Designs and Performance Analysis

Abstract

Fifteen alternative process designs for the production of synthetic gasoline from coal, biomass, or coal+biomass via gasification, methanol synthesis, and methanol-to-gasoline synthesis are analyzed, including some that produce a substantial electricity co-product and some that employ CO 2 capture, with CO 2 stored in deep saline formations or via injection for enhanced oil recovery. This paper reports process mass/energy balance simulation results and fuel-cycle greenhouse gas (GHG) emissions comparisons. A companion paper addresses economic and strategic issues. Key findings of the performance analysis include: i) for two plants designed with the same liquid fuel output, but with one co-producing electricity, the additional feedstock needed for coproduction is converted to electricity more efficiently than if that feedstock were used in a stand-alone power plant; ii) plants using only coal as feedstock have fuel-cycle GHG emissions greater than the conventional fossil fuels their products would displace, except for a coproduction system with CO 2 capture and storage (CCS) which has about 40% less emissions; iii) plants that co-process 35% to 47%sustainably-provided biomass with coal achieve net zero fuel-cycle GHG emissions; iv) the logistics of biomass supply constrain these latter plants to modest scales (< 10,000 barrels per day gasoline); and v) a biomass-only plant with CCS has highly negative net GHG emissions and a more severe scale constraint (~ 4,000 bpd).

Comparison of Coal/Biomass Co-processing Systems with CCS for Production of Low-carbon Synthetic Fuels: Methanol-to-Gasoline and Fischer-tropsch

“…For all the cases, we have developed detailed mass, energy, and carbon balance simulations using Aspen Plus software, as described by Liu et al 5,6 The amount of coal processed at each facility is set using different criteria. For coal-only systems maximizing liquid fuels production, the plants are designed with coal input that results in 50,000 barrels per day of FT fuels or synthetic gasoline production.…”

“…The wholesale price of conventional LPG is estimated as a function of crude oil price from a regression correlation of wholesale propane prices and refiner crude oil acquisition costs in the U.S. propane ($/bbl) = 0.7062* Crude acquisition cost ($/bbl) + 5.5852. 6 …”

“…5 By co-processing some sustainably produced biomass with coal to make FT or MTG fuels and using CCS, fuel-cycle GHG emissions of the resulting fuels can be as low as zero, thereby providing both energy security and carbon mitigation benefits. 5,6,7 This paper presents a detailed comparative technical and economic assessment of the production from coal or coal/biomass of synthetic diesel and gasoline via FT synthesis and synthetic gasoline via MTG technology. Designs include ones without and with CCS and ones without and with substantial electricity co-production.…”

Gasoline from Coal via DME with Electricity Co-production and CO2 Capture

“…Most of the important process design parameter assumptions are the same as used by Liu, et al 2 For the one-step DME synthesis, we predict the DME production and purge gas composition from Eqns. 1 to 3, assuming chemical equilibrium.…”

“…1 Liu, et al 2 have analyzed the performance and cost of coal gasification based gasoline production systems with CO 2 capture and using the methanol-to-gasoline (MTG) process 3 of ExxonMobil. MTG is a two-step process in which synthesis gas is first converted to methanol in a fixed-bed reactor over a copper-based hydrogenation catalyst.…”