Novel carbons from Illinois coal for natural gas storage. Technical report, September 1--November 30, 1994

The goal of this project is to develop a technology for producing microengineered adsorbent carbons from Illinois coal and to evaluate the potential application of these novel materials for storing natural gas for use in emerging low pressure, natural gas vehicles (NGV). Potentially, about two million tons of adsorbent could be consumed in natural gas vehicles by year 2000. If successful, the results obtained in this project could lead to the use of Illinois coal in a growing and profitable market that could exceed 6 million tons per year. During this reporting period, a pyrolysis-gasification reactor system was designed and assembled. Four carbon samples were produced from a {minus}20+100 mesh size fraction of an Illinois Basin Coal (IBC-106) using a three-step process. The three steps were: coal oxidation in air at 250 C, oxicoal (oxidized coal) devolatilization in nitrogen at 425 C and char gasification in 50% steam-50% nitrogen at 860 C. These initial tests were designed to evaluate the effects of pre-oxidation on the surface properties of carbon products, and to determine optimum reaction time and process conditions to produce an activated carbon with high surface area. Nitrogen-BET surface areas of the carbon products ranged from 700--800 m{sup 2}/g. Work is in progress to further optimize reaction conditions in order to produce carbons with higher surface areas. A few screening tests were made with a pressurized thermogravimetric (PTGA) to evaluate the suitability of this instrument for obtaining methane adsorption isotherms at ambient temperature and pressures ranging from one to 30 atmospheres. The preliminary results indicate that PTGA can be used for both the adsorption kinetic and equilibrium studies