Rate inhibition of steam gasification by adsorbed hydrogen. Technical progress report, October 1--December 31, 1995

Efforts during the ninth quarter of the grant period have focused on completing core matrix experiments and initiating experiments with coal char in addition to Saran char. Experimental progress was delayed somewhat during this quarter, as the turbomolecular pump on the mass spectrometer vacuum system malfunctioned and had to be replaced. That resulted in a one-month shutdown of the apparatus. During that time, progress was made on preparation of theses, manuscripts for publication, and proposals for future funding. New results this quarter include reactions to intermediate levels of conversion (20--30%) and correction of hydrogen content for char aging in several samples. The authors can now state conclusively that surface hydrogen concentration following gasification exclusively depends only conversion and not on gasification conditions such as gas composition or pressure. Surface hydrogen concentration initially increases very rapidly to about 10 cm{sup 3}/g at 1% carbon conversion, and then slowly increases out to 90 cm{sup 3}/g at 70% conversion, the highest levels they have measured. Initial results of gasification with unannealed and annealed coal char are given; results for unannealed and annealed Saran char are also given for comparison