Oil shale ash-layer thickness and char combustion kinetics

Conference · Wed Apr 15 04:00:00 EDT 1992

OSTI ID:7296445

Aldis, D F; Singleton, M F; Watkins, B E; Thorsness, C B; Cena, R J

A Hot-Recycled-Solids (HRS) oil shale retort is being studied at Lawrence Livermore National Laboratory. In the HRS process, raw shale is heated by mixing it with burnt retorted shale. Retorted shale is oil shale which has been heated in an oxygen deficient atmosphere to pyrolyze organic carbon, as kerogen into oil, gas, and a nonvolatile carbon rich residue, char. In the HRS retort process, the char in the spent shale is subsequently exposed to an oxygen environment. Some of the char, starting on the outer surface of the shale particle, is burned, liberating heat. In the HRS retort, the endothermic pyrolysis step is supported by heat from the exothermic char combustion step. The rate of char combustion is controlled by three resistances; the resistance of oxygen mass transfer through the gas film surrounding the solid particle, resistance to mass transfer through a ash layer which forms on the outside of the solid particles as the char is oxidized and the resistance due to the intrinsic chemical reaction rate of char and oxygen. In order to estimate the rate of combustion of the char in a typical oil shale particle, each of these resistances must be accurately estimated. We begin by modeling the influence of ash layer thickness on the over all combustion rate of oil shale char. We then present our experimental measurements of the ash layer thickness of oil shale which has been processed in the HRS retort.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7296445
• Report Number(s): UCRL-JC-109240; CONF-9204147--4; ON: DE92019537
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
040500* -- Oil Shales & Tar Sands-- Properties & Composition
ASHES
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHARS
CHEMICAL REACTION KINETICS
COMBUSTION PRODUCTS
COMBUSTION PROPERTIES
ENERGY SOURCES
FOSSIL FUELS
FUELS
HEATING RATE
KINETICS
LAYERS
MASS TRANSFER
MATERIALS
MATHEMATICAL MODELS
OIL SHALES
PYROLYSIS PRODUCTS
REACTION KINETICS
RESIDUES
ROCKS
SEDIMENTARY ROCKS
SHALES