TITLE: Hydrogasification of carbon adsorbed on sulfur-poisoned dispersed metal catalysts. Final report.

AUTHOR: J. G. McCarty;   B. J. Wood.

INST.  AUTHOR: SRI International, Menlo Park, CA. Materials Research Lab.

SPONSOR: Department of Energy, Washington, DC.

LANGUAGE: English

PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  Dec 93,  12p.

NTIS ORDER NO.: DE94005845INW

ABSTRACT:

The temperature programmed reaction of 1- to 10-atom hydrogen (TPRH) with carbon deposited on alumina supported Ni, Ru, and Co and on fused Fe catalysts has been developed to examine the effect of sulfur poisoning on coking rates and the nature of the deposited carbon. A new procedure, passivation by carbon deposition on clean reduced metals and low temperature (20--50 C) exposure to recirculate dilute H(sub 2)S with moderate 0.1 atm partial pressure of CO(sub 2) was used to slow the rate of sulfur chemisorption. This method facilitated slow uniform sulfur chemisorption to fractional saturation coverages. Fractional sulfur poisoning generally blocked sites of active surface carbon (or hydrocarbon fragments) while suppressing rates of hydrogasification as shown by the increasing temperatures in the TPRH hydrogasification rate versus temperature spectra. Fractional sulfur poisoning (e.g., half saturation) appears to inhibit H(sub 2) gasification with surface carbon surprisingly without strongly affecting catalytic activity. Sulfur poisoning to saturation levels (defined here as (approximately)1 ppm H(sub 2)S in 1-atm H(sub 2) at 500 C) always results in complete loss of activity and is also marked by the growth of a very unreactive form of carbon.

REPORT  NUMBER: DOE/ER/13689-T3

CONTRACT  NUMBER: FG03-87ER13689