Economics of gasoline production from underground coal gasification via Mobil-M process

A conceptual process design and cost estimate is presented for a facility producing approximately 100 m/sup 3//h (15,000 barrels per day) of M-gasoline via methanol from synthesis gas generated by gasification of coal in situ. The design was based on experimental data obtained at the Laramie Energy Technology Center on the linked vertical well in situ coal gasification process. In-place coal consumption is 756 Mg/h (20,000 tons/day), based on a subbituminous Wyoming coal. The capital investment was estimated to be $535 million in first quarter 1978 dollars. M-gasoline product price was calculated as a function of debt/equity ratio, annual earning rates on debt and equity, in-place coal cost, and plant factor (onstream efficiency). Using a debt/equity ratio of 70/30, an interest rate on debt of 9%, an after-tax earning rate on equity of 15%, an in-place coal cost of $5.50/Mg ($5/ton), an LPG (propane) by-product credit of $3.80/GJ ($4/10/sup 6/ Btu), and a plant factor of 90%, the product price of M-gasoline (including mixed butane LPG) is about $240/m/sup 3/ ($0.90/gas) at the plant gate. Calculated overall thermal efficiency for the facility was 22%, based on in-place coal.