Coal liquids hydrotreatment: catalyst pore size effects

Conference · Fri Sep 01 04:00:00 EDT 1978 · Prepr., Div. Pet. Chem., Am. Chem. Soc.; (United States)

OSTI ID:6019668

Ahmed, M M; Crynes, B L

CO--Mo--Alumina catalysts are widely used in hydrotreatment operations. The active metals, cobalt and molybdenum, are present in the form of oxides in fresh catalysts. The sulfided form is observed to be responsible for the hydrotreating action of the catalyst. Most of the surface area of these catalysts lies within the internal porous structure. Access to the active sites within the catalysts pores depends on the support properties such as surface area and pore size distribution. In the case of coal-derived liquids, a variety of polynuclear aromatic compounds with a broad spectrum of molecular sizes are encountered. For efficient utilization of the catalyst, these molecules should diffuse into the porous structure to reach the active sites. Pore diffusional limitations have been observed in the hydrotreatment of petroleum crudes. Very little information is available regarding such effects in the hydrotreatment of coal derived liquids. The objective of this paper is to compare the activities of three Co--Mo--Alumina catalysts for hydrotreating coal-derived liquids. From the results the following conclusions can be drawn: (a) A reduction in the most frequent pore radius can result in a decreased activity for heteroatom removal from coal-derived liquids. (b) The relative size of the coal liquid molecules with respect to the pore diameter can play an important role in pore diffusion limited cases. (c) There can be an optimum pore size distribution for heteroatom removal from coal-derived liquids. (d) Catalysts lose surface area due to coking and ash depositions during coal liquids hydrotreatment operations. Most of the lost surface area can be recovered by burning off the carbonaceous deposits. (e) Ash depositions seem to cause permanent loss in catalyst surface area and pore volume.

• Research Organization: Oklahoma State Univ., Stillwater
• OSTI ID: 6019668
• Report Number(s): CONF-780902-P4
• Conference Information: Journal Name: Prepr., Div. Pet. Chem., Am. Chem. Soc.; (United States) Journal Volume: 23:4
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010402 -- Coal
Lignite
& Peat-- Purification & Upgrading
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COAL LIQUIDS
COBALT
CRYOGENIC FLUIDS
CRYSTAL STRUCTURE
DEACTIVATION
ELEMENTS
FLUIDS
HYDROGENATION
METALS
MICROSTRUCTURE
MOLYBDENUM
NITROGEN
NONMETALS
POROSITY
REFRACTORY METALS
REMOVAL
SULFUR
TRANSITION ELEMENTS