An Evaluation of Low-BTU Gas from Coal as an Alternate Fuel for Process Heaters

As the price gap between oil and natural gas and coal continues to widen, Monsanto has carefully searched out and examined opportunities to convert fuel use to coal. Preliminary studies indicate that the low-btu gas produced by fixed-bed, air blown gasifiers could potentially replace the natural gas now used in process heaters. The technology is well established and requires less capital than the higher-btu process heaters. Low-btu gas has sufficient heating value and flame temperature to be acceptable fuel for most process heaters. Economics for gas production appear promising, but somewhat uncertain. Rough evaluations indicate rates of return of as much as 30-40%. However, the economics are very dependent on a number of site- specific considerations including: coal vs. natural gas prices, economic life of the gas-consuming facility, quantity of gas required, need for desulfurization, location of gasifiers in relation to gas users, existence of coal unloading and storage facilities, etc. Two of these factors, the difference between coal and natural gas prices and the project life are difficult to predict. The resulting uncertainty has caused Monsanto to pursue coal gasification for process heaters with cautious optimism, on a site by site basis