Mineral oils: processes and products – By treatment of solid mineral – e.g. – coal liquefaction – etc. – Including burning of feed or product
Patent
1983-08-24
1986-10-14
Metz, Andrew H.
Mineral oils: processes and products
By treatment of solid mineral, e.g., coal liquefaction, etc.
Including burning of feed or product
208428, C10G 100
Patent
active
046171070
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an improved continuous process for the recovery of hydrocarbon values, that is, oil and gaseous products, from oil shale with the simultaneous maximization of energy recovery from by-product streams.
Oil is conventionally recovered from oil shales by retorting at temperatures in the range of 400.degree. to 600.degree. C. The gaseous products evolved simultaneously with oil vapours during retorting comprise hydrogen and light hydrocarbons as well as impurities, such as carbon oxides and hydrogen sulphide. The solids residue after retorting contains a substantial portion of the fuel value of the original raw shale and is typically referred to as "spent shale". The oil yield and quality depends on the raw, or sometimes called fresh, shale assay and on the operating conditions in the retort. The raw shale oil must always be upgraded in one or several steps which include hydrotreatment.
BACKGROUND ART
One of the major problems with such a process is an efficient and economic manner of heat supply for oil shale retorting. Various solid and gaseous heat carriers have been proposed for retorting oil shale. Substantial dilution of the product vapours and gases from retorting occurs if the heat carrier is hot flue gas, generated for example by combustion of spent shale. Hot recycle gases such as hydrogen, beside having the above drawback, must be heated in a separate furnace using additional fuel and hence the overall thermal efficiency is decreased. Steam as a sole heat carrier is also thermally inefficient because of its high condensation heat.
Solid heat carriers have none of the above drawbacks but good mixing with raw shale must be provided in order to achieve a reasonable rate of heat transfer from the heat carrier solids to the raw shale particles. The TOSCO II process, for example, uses ceramic balls as the heat carrier which deliver their sensible heat to oil shale particles in a rotary retort. The balls must be separated from the smaller spent shale particles after retorting, usually by screening. The balls are then lifted by a mechanical elevator and heated by combustion gases, produced from burning external fuel, in a co-current moving bed heater. The raw shale particles are preheated in order to improve the thermal efficiency of the process and to minimize the expensive recirculation rate of the balls, and preheating is done in a series of dilute phase lift pipe heaters by hot gases leaving the ball heater.
The Lurgi process also uses a solid heat carrier in the form of particulate shale solids heated in a dilute phase lift pipe by partial combustion of residual carbonaceous matter. However, the residence time of solids in the pipe is short and usually only a small fraction of the fuel value of the spent shale is recovered and transferred to the heat carrier solids. Consequently, a large amount of recirculated heat carrier solids is needed to provide the necessary heat for the raw shale retorting. This can cause difficulty in controlling the quality and quantity of the oil product. Before entering the fluidized bed or moving bed retort, the two streams of solids are intensively mixed in a screw type mixer, and so the operation requires reasonable strengths of particles. For the abovementioned reasons, raw shale is also preheated by hot flue gases.
DISCLOSURE OF THE INVENTION
It is an object of this invention to provide a continuous process for the recovery of hydrocarbon values from oil shale using as a heat carrier the hot shale solids residue, which process does not have the aforementioned problems.
It has now been discovered that high yields and good quality of products, and a high thermal efficiency of the process can be achieved: by carrying out retorting in a retort in which the solids are well mixed, to which a purge gas which is also a reactant is supplied and by incorporating both the generation of a solid heat carrier and recovery of energy by combustion of spent shale in, for instance, one fluidized bed reactor, where the chemistry of the major
REFERENCES:
patent: 1343100 (1920-06-01), Thurlow
patent: 1703192 (1929-02-01), Hampton
patent: 2441386 (1948-05-01), Berg
patent: 3058904 (1962-10-01), Deering et al.
patent: 3252886 (1966-05-01), Crawford
patent: 3421868 (1969-01-01), Feldman
patent: 3464913 (1969-09-01), Berry
patent: 3487004 (1969-12-01), Berry
patent: 3546092 (1968-06-01), Whiteacre, 3rd
patent: 3573197 (1971-03-01), Gessner
patent: 3784462 (1974-01-01), Frick
patent: 3976558 (1976-08-01), Hall
patent: 4061105 (1977-01-01), Gifford, II
patent: 4063823 (1977-01-01), Baird, Jr. et al.
patent: 4071432 (1978-01-01), Knell et al.
patent: 4133381 (1979-01-01), Stewart
patent: 4183800 (1980-01-01), Mitchell et al.
patent: 4389950 (1983-06-01), Bertelsen
patent: 4396490 (1983-08-01), York
patent: 4404683 (1983-09-01), Vasalas
"The Properties of Spent Shale," Synthetic Fuels Data Handbook, Hendrickson, Cameron Engines Inc., 1975, pp. 91-93.
Mandelson John
McCarthy David J.
Sitnai Oto
Whitehead Alan B.
Comonwealth Scientific and Industrial Research Organization and
Metz Andrew H.
Myers Helane
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