Fluid bed retorting process and system

Claim 2

A fluid bed process for use in producing synthetic fuels, comprising the steps of: commencing retorting of raw solid, hydrocarbon-containing material selected from the group consisting of oil shale, tar sands, uintaite, lignite and peat in a mixing chamber having a maximum transverse cross-sectional area substantially greater than the maximum transverse cross-sectional area of a vertical lift pipe extending substantially vertically above said mixing chamber by feeding said raw solid, hydrocarbon-containing material and substantially completely combusted solid heat carrier material into said mixing chamber through separate feed lines and injecting a fluidizing lift gas into said mixing chamber separately from said combusted material, in the absence of a sufficient amount of air and molecular oxygen to support combustion, to fluidize and mix said raw and combusted material in said mixing chamber; continuing retorting and fluidizing of said raw solid, hydrocarbon-containing material with said substantially completely combusted material and said fluidizing lift gas in said lift pipe located in vertical alignment above said mixing chamber; and substantially completing retorting of said solid, hydrocarbon-containing material with said substantially completely combusted material in an overhead solids-containing vessel positioned in vertical and coaxial alignment above said lift pipe and said mixing chamber.

Claim 3

A fluid bed process in accordance with claim 1 further including controlling the retorting time in said mixing chamber and said lift pipe by transporting said raw solid-hydrocarbon material and said substantially completely combusted material generally upwardly through said mixing chamber with said fluidizing lift gas at a first selected flow velocity and generally upwardly through said lift pipe at a faster second selected flow velocity, and wherein said retorting is substantially completed in a solids-containing vessel having a maximum transverse cross-sectional area substantially greater than the maximum transverse cross-sectional area of said mixing chamber.

Claim 4

A fluid bed process for retorting oil shale for use in producing synthetic fuels, comprising the steps of: feeding raw fluidizable oil shale into a mixing chamber having a maximum transverse cross-sectional area substantially greater than the maximum transverse cross-sectional area of a vertical lift pipe extending substantially vertically above said mixing chamber; feeding fluidizable substantially combusted spent oil shale into said mixing chamber; heating said fluidizable raw oil shale in said mixing chamber by contacting said raw oil shale with said substantially combusted spent oil shale fed into said mixing chamber at a temperature sufficient to liberate shale oil and light hydrocarbon gases from said raw oil shale without decomposing a substantial amount of carbonates; fluidizing and mixing said raw and substantially combusted shale in said mixing chamber by injecting a fluidizing lift gas into said mixing chamber separately from said shale at a pressure and flow rate sufficient to transport said raw and combusted shale, shale oil and light hydrocarbon gases generally upward through said mixing chamber to said lift pipe for a sufficient residence time to partially retort said raw oil shale in said mixing chamber while minimizing cracking of said shale oil and light hydrocarbon gases emitted therefrom; conveying said shale and said liberated shale oil and light hydrocarbon gases generally upwardly through said lift pipe to an overhead solids-containing vessel positioned in vertical alignment above said lift pipe with said fluidizing lift gas for a sufficient residence time to continue retorting of said row oil shale while minimizing cracking of said shale oil and light hydrocarbon gases; moving said conveyed shale generally downwardly in said solids-containing vessel to a solids discharge outlet by gravity flow for a sufficient residence time to substantially complete retorting of said raw oil shale while minimizing cracking of said liberated shale oil and light hydrocarbon gases; substantially preventing combustion of said raw oil shale, shale oil and light hydrocarbon gases in said mixing chamber, lift pipe and vessel by substantially preventing air from entering therein; withdrawing said shale oil and gases from an upper portion of said solids-containing vessel; discharging said shale from said solids discharge outlet; transporting said discharged shale to the bottom portion of a combustor lift pipe; combusting, fluidizing and carrying said discharged shale generally upwardly in said combustor lift pipe with air to a combustor vessel positioned in vertical alignment above said combustor lift pipe; substantially completing combustion of said discharged shale in said combustor vessel; withdrawing combustion gases from said combustor vessel; removing said combusted shale from said combustor vessel; and feeding said combusted shale to said mixing chamber.

Claim 5

A fluid bed process for retorting oil shale for use in producing synthetic fuels, comprising the steps of: feeding raw fluidizable oil shale into a mixing chamber having a maximum transverse cross-sectional area substantially greater than the maximum transverse cross-sectional area of a vertical lift pipe extending substantially vertically above said mixing chamber; feeding fluidizable substantially combusted spent oil shale into said mixing chamber; heating said fluidizable raw oil shale in said mixing chamber by contacting said raw oil shale with said substantially combusted spent oil shale fed into said mixing chamber at a temperature sufficient to liberate shale oil and light hydrocarbon gases from said raw oil shale without decomposing a substantial amount of carbonates; fluidizing and mixing said raw and substantially combusted shale in said mixing chamber by injecting a fluidizing lift gas into said mixing chamber separately from said shale at a pressure and flow rate sufficient to transport said raw and combusted shale, shale oil and light hydrocarbon gases generally upward through said mixing chamber to said lift pipe for a sufficient residence time to partially retort said raw oil shale in said mixing chamber while minimizing cracking of said shale oil and light hydrocarbon gases emitted therefrom; conveying said shale and said liberated shale oil and light hydrocarbon gases generally upwardly through said lift pipe to an overhead solids-containing vessel positioned in vertical alignment above said lift pipe with said fluidizing lift gas for a sufficient residence time to continue retorting of said row oil shale while minimizing cracking of said shale oil and light hydrocarbon gases; moving said conveyed shale generally downwardly in said solids-containing vessel to a solids discharge outlet by gravity flow for a sufficient residence time to substantially complete retorting of said raw oil shale while minimizing cracking of said liberated shale oil and light hydrocarbon gases; substantially preventing combustion of said raw oil shale, shale oil and light hydrocarbon gases in said mixing chamber, lift pipe and vessel by substantially preventing air from entering therein; withdrawing said shale oil and gases from an upper portion of said solids-containing vessel; discharging said shale from said solids discharge outlet; transporting said discharged shale to the bottom portion of a combustor lift pipe; combusting, fluidizing and carrying said discharged shale generally upwardly in said combustor lift pipe with air to a combustor vessel positioned in vertical alignment above said combustor lift pipe; substantially completing combustion of said discharged shale in said combustor vessel; withdrawing combustion gases from said combustor vessel; removing said combusted shale from said combustor vessel; and feeding said combusted shale to said mixing chamber.

Claim 6

A fluid bed process in accordance with claim 3 further including the step of baffling said shale in said solids-containing vessel to facilitate downward movement and help minimize backmixing of said shale.

Claim 7

A fluid bed process in accordance with claim 3 including recycling said light hydrocarbon gas from said solids-containing vessel to said mixing chamber for use as said fluidizing lift gas.

Claim 8

A fluid bed process in accordance with claim 3 wherein said fluidizing lift gas includes from about 10% to about 30% by weight carbon dioxide to help suppress carbonate decomposition during retorting.

Claim 9

A fluid bed process in accordance with claim 3 including forming a spouted bed in said mixing chamber with said fluidizing lift gas.

Claim 10

A fluid bed process for retorting oil shale, comprising the steps of: feeding fluidizable raw oil shale particles between ambient temperature and 700° F. into a mixing chamber having a maximum transverse cross-sectional area substantially greater than the maximum transverse cross-sectional area of a vertical lift pipe extending substantially vertically above said mixing chamber; feeding fluidizable, substantially completely combusted spent oil shale at a temperature from 1000° F. to 1400° F. into said mixing chamber at a solids flux flow rate ratio of combusted oil shale to raw oil shale from 3:1 to 10:1; fluidizing and mixing said combusted oil shale and said raw oil shale in said mixing chamber at a temperature from 900° F. to 1200° F. for a sufficient time to partially retort said raw oil shale in said mixing chamber without cracking a substantial proportion of said shale oil and light hydrocarbon gases emitted therefrom by injecting a fluidizing lift gas in the absence of air and molecular oxygen at a pressure from 30 psig to 100 psig, between ambient temperature and 1000° F., into said mixing chamber to transport and entrain said shale generally upwardly through said mixing chamber at a velocity of 2 ft/sec to 4.5 ft/sec into said lift pipe, said gas having a residence time in said mixing chamber of 0.5 seconds to 5 seconds, said mixing chamber being maintained at a pressure of 30 psig to 50 psig; conveying said shale oil and said shale generally upwardly through said lift pipe at a solids density of 3 lbs/ft 3 to 20 lbs/ft 3 with said gases to an overhead solids-containing vessel positioned in vertical and coaxial alignment with and above said vertical lift pipe and said mixing chamber and having a transverse cross-sectional area from 5 to 10 times greater than said mixing chamber to continue retorting said raw oil shale in said lift pipe without cracking a substantial proportion of the liberated shale oil and light hydrocarbon gases; gravitating said shale generally downwardly in said solids-containing vessel to a solids discharge outlet to substantially complete retorting of said raw oil shale in said solids-containing vessel without cracking a substantial proportion of the liberated shale oil and light hydrocarbon gases; withdrawing said shale oil and gases from an upper portion of said solids-containing vessel; discharging said shale from said solids outlet to a combustor; and substantially completely combusting said shale in a combustor.

Claim 11

A fluid bed process for retorting oil shale, comprising the steps of: feeding fluidizable raw oil shale particles between ambient temperature and 700° F. into a mixing chamber having a maximum transverse cross-sectional area substantially greater than the maximum transverse cross-sectional area of a vertical lift pipe extending substantially vertically above said mixing chamber; feeding fluidizable, substantially completely combusted spent oil shale at a temperature from 1000° F. to 1400° F. into said mixing chamber at a solids flux flow rate ratio of combusted oil shale to raw oil shale from 3:1 to 10:1; fluidizing and mixing said combusted oil shale and said raw oil shale in said mixing chamber at a temperature from 900° F. to 1200° F. for a sufficient time to partially retort said raw oil shale in said mixing chamber without cracking a substantial proportion of said shale oil and light hydrocarbon gases emitted therefrom by injecting a fluidizing lift gas in the absence of air and molecular oxygen at a pressure from 30 psig to 100 psig, between ambient temperature and 1000° F., into said mixing chamber to transport and entrain said shale generally upwardly through said mixing chamber at a velocity of 2 ft/sec to 4.5 ft/sec into said lift pipe, said gas having a residence time in said mixing chamber of 0.5 seconds to 5 seconds, said mixing chamber being maintained at a pressure of 30 psig to 50 psig; conveying said shale oil and said shale generally upwardly through said lift pipe at a solids density of 3 lbs/ft 3 to 20 lbs/ft 3 with said gases to an overhead solids-containing vessel positioned in vertical and coaxial alignment with and above said vertical lift pipe and said mixing chamber and having a transverse cross-sectional area from 5 to 10 times greater than said mixing chamber to continue retorting said raw oil shale in said lift pipe without cracking a substantial proportion of the liberated shale oil and light hydrocarbon gases; gravitating said shale generally downwardly in said solids-containing vessel to a solids discharge outlet to substantially complete retorting of said raw oil shale in said solids-containing vessel without cracking a substantial proportion of the liberated shale oil and light hydrocarbon gases; withdrawing said shale oil and gases from an upper portion of said solids-containing vessel; discharging said shale from said solids outlet to a combustor; and substantially completely combusting said shale in a combustor.

Claim 12

A fluid bed process in accordance with claim 8 wherein said raw oil shale is fed into said mixing chamber at a temperature from 250° F. to 600° F. and said completely combusted shale is fed into said mixing chamber at a temperature from 1100° F. to 1300° F.

Claim 13

A fluid bed process in accordance with claim 8 wherein said raw oil shale is fed into said mixing chamber at a temperature from 300° F. to 400° F. and said completely combusted shale is fed into said mixing chamber at a temperature from 1150° F. to 1250° F.

Claim 14

A fluid bed process in accordance with claim 8 where at least some of said light hydrocarbon gases are recycled from said solids-containing vessel to said mixing chamber and used for at least a portion of said fluidizing lift gas.

Claim 15

A fluid bed process in accordance with claim 8 wherein said shale is combusted by: moving said discharged shale by gravity flow to the bottom portion of a combustor lift pipe injecting air into the bottom portion of said combustor lift pipe at a velocity of 20 ft/sec to 75 ft/sec and at a pressure from 20 psig to 80 psig; partially burning carbon residue contained in said retorted oil shale in said combustor lift pipe at a temperature from 1000° F. to 1400° F.; transporting and fluidizing said partially burnt shale with said air substantially vertically upwardly to a combustor vessel positioned generally vertically above said combustor lift pipe; substantially completing combustion of the carbon residue contained in said oil shale in 1 minute to 10 minutes in said combustor vessel; withdrawing combustion gases from an upper portion of said combustor vessel; and discharging said combusted oil shale by gravity flow from the lower portion of said combustor vessel to said mixing chamber.