Sulfur poisoning of catalysts. Quarterly progress report, 1 July--30 September 1976. [Methanol synthesis from H/sub 2/ and CO; 17 refs]

Technical Report · Mon Nov 01 04:00:00 EST 1976

OSTI ID:7233172

Isakson, W E; Sancier, K M; Wise, H; Wood, B J

This study concerns the deactivation of catalysts used to produce fuels from CO and H/sub 2/O. The first phase of this research emphasized S poisoning of methanol-synthesis catalysts. During this reporting period an examination has been started of the role of C in Fischer-Tropsch catalysts. A discussion is presented of surface sulfidation and segregation with methanol-synthesis catalysts and the kinetics of C formation on Fischer-Tropsch catalysts. The thermodynamics and surface structures of S chemisorbed on transition metals are reviewed in the Appendix. Several iron-based Fisher-Tropsch catalysts were examined during reduction and carburization by thermogravimetric (TGA) and thermomagnetic (TMA) analyses. Catalyst B6 was reduced in H/sub 2/ and carburized in H/sub 2//CO = 3 at atmospheric pressure. The results indicate that the fresh catalyst contains 77 wt% ..gamma..-Fe/sub 3/O/sub 4/, the remainder is ..cap alpha..-Fe, promoters, and possibly, some carbidic compounds. Carburization carried out under temperature programming conditions in the range of 175 to 324/sup 0/C results in the formation of Hagg carbide, Fe/sub 2/C, as the only ferromagnetic phase. Carburizations performed isothermally indicate the formation of: Hagg carbide at 300 and 224/sup 0/C, a mixture of Hagg and hexagonal Fe/sub 2/C at 250/sup 0/C, and hexagonal Fe/sub 2/C at 200/sup 0/C. Formation of a precursor carbide is suggested during early stages of carburization at 324/sup 0/C. The TGA results indicate the existence of two successive diffusion-limited carburization rates. From the temperature dependence of these two rates processes, the isothermal work of diffusion was calculated to be 9.5 and 6.5 kcal mol/sup -1/.

• Research Organization: Stanford Research Inst., Menlo Park, CA (USA)
• OSTI ID: 7233172
• Report Number(s): PERC-0060-5
• Country of Publication: United States
• Language: English

Related Subjects

090221* -- Alcohol Fuels-- Chemical Synthesis-- (1976-1989)
10 SYNTHETIC FUELS
ALCOHOLS
CARBIDES
CARBON
CARBON COMPOUNDS
CARBURIZATION
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHEMISORPTION
CRYSTAL STRUCTURE
ELEMENTS
FISCHER-TROPSCH SYNTHESIS
GRAVIMETRIC ANALYSIS
HARDENING
HYDROXY COMPOUNDS
IRON
IRON COMPOUNDS
IRON OXIDES
KINETICS
MAGNETISM
METALS
METHANOL
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POISONING
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SULFUR
SURFACE HARDENING
SURFACE PROPERTIES
SURFACE TREATMENTS
SYNTHESIS
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
THERMOMAGNETISM
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YIELDS