Low temperature oxidation of hydrogen sulfide in the presence of oil shale

Claim 1

A method for recovering gaseous products from a first in situ oil shale retort in a subterranean formation containing oil shale, said first in situ retort containing an explosively expanded and fragmented permeable mass of particles containing oil shale and having a combustion zone and a retorting zone advancing therethrough, the method comprising the steps of: (a) introducing into the first in situ oil shale retort on the trailing side of the combustion zone a combustion zone feed comprising oxygen to advance the combustion zone through the fragmented mass of particles and produce combustion gas in the combustion zone; (b) passing said combustion gas and any unreacted portion of the combustion zone feed through a retorting zone in the fragmented mass of particles on the advancing side of the combustion zone, wherein oil shale is retorted and gaseous products including hydrocarbons are produced; (c) withdrawing a retort off gas comprising said gaseous products including hydrocarbons, combustion gas and any gaseous unreacted portions of the combustion zone feed from the first in situ oil shale retort from the advancing side of the retorting zone; and (d) reducing the hydrogen sulfide concentration of retort off gas from the first retort by the steps of: (i) during a first period of time introducing a gaseous combustion zone feed containing oxygen into a combustion zone in a second in situ oil shale retort in a subterranean formation containing oil shale and including alkaline earth metal carbonates, said second in situ retort containing an explosively expanded and fragmented permeable mass of formation particles containing oil shale and alkaline earth metal carbonates, wherein the gaseous combustion zone feed advances the combustion zone through the fragmented mass of particles and converts at least a portion of the alkaline earth metal carbonates to alkaline earth metal oxides and produces combusted oil shale particles; and thereafter (ii) during a second period of time introducing at least a portion of the retort off gas from the first retort into the second retort, introducing oxygen containing gas into the second retort for reacting at a temperature less than about 650° F oxygen in the oxygen containing gas with hydrogen sulfide in the retort off gas in the presence of combusted oil shale in the second retort to form compounds containing sulfur and oxygen, wherein at least a portion of the formed compounds containing sulfur and oxygen combine with alkaline earth metal oxides contained in the second retort, wherein gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the off gas is produced, and withdrawing such gas with relatively lower hydrogen sulfide concentration from the second retort.

Claim 2

A method for recovering gaseous products from a first in situ oil shale retort in a subterranean formation containing oil shale, said first in situ retort containing an explosively expanded and fragmented permeable mass of particles containing oil shale and having a combustion zone and a retorting zone advancing therethrough, the method comprising the steps of: (a) introducing into the first in situ oil shale retort on the trailing side of the combustion zone a combustion zone feed comprising oxygen to advance the combustion zone through the fragmented mass of particles and produce combustion gas in the combustion zone; (b) passing said combustion gas and any unreacted portion of the combustion zone feed through a retorting zone in the fragmented mass of particles on the advancing side of the combustion zone, wherein oil shale is retorted and gaseous products including hydrocarbons are produced; (c) withdrawing a retort off gas comprising said gaseous products including hydrocarbons, combustion gas and any gaseous unreacted portions of the combustion zone feed from the first in situ oil shale retort from the advancing side of the retorting zone; and (d) reducing the hydrogen sulfide concentration of retort off gas from the first retort by the steps of: (i) during a first period of time introducing a gaseous combustion zone feed containing oxygen into a combustion zone in a second in situ oil shale retort in a subterranean formation containing oil shale and including alkaline earth metal carbonates, said second in situ retort containing an explosively expanded and fragmented permeable mass of formation particles containing oil shale and alkaline earth metal carbonates, wherein the gaseous combustion zone feed advances the combustion zone through the fragmented mass of particles and converts at least a portion of the alkaline earth metal carbonates to alkaline earth metal oxides and produces combusted oil shale particles; and thereafter (ii) during a second period of time introducing at least a portion of the retort off gas from the first retort into the second retort, introducing oxygen containing gas into the second retort for reacting at a temperature less than about 650° F oxygen in the oxygen containing gas with hydrogen sulfide in the retort off gas in the presence of combusted oil shale in the second retort to form compounds containing sulfur and oxygen, wherein at least a portion of the formed compounds containing sulfur and oxygen combine with alkaline earth metal oxides contained in the second retort, wherein gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the off gas is produced, and withdrawing such gas with relatively lower hydrogen sulfide concentration from the second retort.

Claim 5

A method of decreasing hydrogen sulfide concentration of a gas comprising the steps of: introducing a gas containing relatively higher hydrogen sulfide concentration to a fragmented permeable mass of oil shale, wherein at least a portion of the oil shale has been treated to remove organic material prior to introducing the gas to the oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the introduced gas with oxygen in the presence of oil shale to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas; and withdrawing such gas having a relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 6

A method of decreasing hydrogen sulfide concentration of a gas comprising the steps of: introducing a gas containing relatively higher hydrogen sulfide concentration to a fragmented permeable mass of oil shale, wherein at least a portion of the oil shale has been treated to remove organic material prior to introducing the gas to the oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the introduced gas with oxygen in the presence of oil shale to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas; and withdrawing such gas having a relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 10

A method for decreasing hydrogen sulfide and total sulfur concentration of off gas from an in situ oil shale retort, the off gas containing fuel value components, comprising the steps of: forming at a temperature less than about 650° F sulfur and oxygen bearing compounds by combining the off gas with oxygen in the presence of a fragmented permeable mass of particles containing oil shale treated to remove organic materials, wherein at least a portion of the treated oil shale is at a temperature greater than about 300° F and at least a portion of the treated oil shale contains alkaline earth metal oxides for combining with the formed sulfur and oxygen bearing compounds, and wherein the treated oil shale contacted by the fuel value components is at a temperature less than the spontaneous ignition temperature of the fuel value components at the conditions at which the treated oil shale is contacted by the fuel value components.

Claim 11

A method for decreasing hydrogen sulfide and total sulfur concentration of off gas from an in situ oil shale retort, the off gas containing fuel value components, comprising the steps of: forming at a temperature less than about 650° F sulfur and oxygen bearing compounds by combining the off gas with oxygen in the presence of a fragmented permeable mass of particles containing oil shale treated to remove organic materials, wherein at least a portion of the treated oil shale is at a temperature greater than about 300° F and at least a portion of the treated oil shale contains alkaline earth metal oxides for combining with the formed sulfur and oxygen bearing compounds, and wherein the treated oil shale contacted by the fuel value components is at a temperature less than the spontaneous ignition temperature of the fuel value components at the conditions at which the treated oil shale is contacted by the fuel value components.

Claim 14

A method for removing hydrogen sulfide from a gas stream comprising the steps of: forming a first in situ oil shale retort in a subterranean formation containing oil shale, said in situ retort containing a fragmented permeable mass of formation particles containing oil shale and alkaline earth metal carbonates; producing combusted oil shale in the first retort by introducing a gaseous combustion zone feed comprising an oxygen supplying gas into a combustion zone in the fragmented mass for advancing the combustion zone through the fragmented mass of particles and producing combustion gas and combined oil shale and converting at least a portion of the alkaline earth metal carbonates to corresponding alkaline earth metal oxides; ending advancement of the combustion zone; thereafter, contacting, in the presence of oxygen, at a temperature greater than about 300° F and less than about 650° F formation particles in the first in situ retort with a process gas with relatively higher hydrogen sulfide concentration to form compounds containing sulfur and oxygen, wherein at least a portion of the formed compounds containing sulfur and oxygen combine with alkaline earth metal oxides contained in the retort to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the process gas; and withdrawing such gas with relatively lower hydrogen sulfide concentration from the first in situ oil shale retort.

Claim 15

A method for removing hydrogen sulfide from a gas stream comprising the steps of: forming a first in situ oil shale retort in a subterranean formation containing oil shale, said in situ retort containing a fragmented permeable mass of formation particles containing oil shale and alkaline earth metal carbonates; producing combusted oil shale in the first retort by introducing a gaseous combustion zone feed comprising an oxygen supplying gas into a combustion zone in the fragmented mass for advancing the combustion zone through the fragmented mass of particles and producing combustion gas and combined oil shale and converting at least a portion of the alkaline earth metal carbonates to corresponding alkaline earth metal oxides; ending advancement of the combustion zone; thereafter, contacting, in the presence of oxygen, at a temperature greater than about 300° F and less than about 650° F formation particles in the first in situ retort with a process gas with relatively higher hydrogen sulfide concentration to form compounds containing sulfur and oxygen, wherein at least a portion of the formed compounds containing sulfur and oxygen combine with alkaline earth metal oxides contained in the retort to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the process gas; and withdrawing such gas with relatively lower hydrogen sulfide concentration from the first in situ oil shale retort.

Claim 17

A method for decreasing hydrogen sulfide concentration of a gas stream comprising the steps of passing a gas containing relatively higher hydrogen sulfide concentration through an in situ oil shale retort containing an explosively fragmented permeable mass of combusted oil shale particles and including alkaline earth metal oxides, while concurrently introducing a source of oxygen into said retort to combine therein at a temperature up to about 650° F with said hydrogen sulfide and alkaline earth metal oxides to form alkaline earth metal sulfites, whereby the gas after passing through the retort is of relatively lower hydrogen sulfide concentration than the gas before passing through the retort.

Claim 18

A method for decreasing hydrogen sulfide concentration of a gas stream comprising the steps of passing a gas containing relatively higher hydrogen sulfide concentration through an in situ oil shale retort containing an explosively fragmented permeable mass of combusted oil shale particles and including alkaline earth metal oxides, while concurrently introducing a source of oxygen into said retort to combine therein at a temperature up to about 650° F with said hydrogen sulfide and alkaline earth metal oxides to form alkaline earth metal sulfites, whereby the gas after passing through the retort is of relatively lower hydrogen sulfide concentration than the gas before passing through the retort.

Claim 22

A method of decreasing hydrogen sulfide and total sulfur concentration of a gas comprising the steps of: introducing a gas with a first hydrogen sulfide concentration of a fragmented permeable mass of oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the gas with oxygen in the presence of the oil shale to yield gas having a second hydrogen sulfide concentration; and withdrawing such gas having the second hydrogen sulfide concentration from the fragmented permeable mass of oil shale, wherein the second hydrogen sulfide concentration is lower than the first hydrogen sulfide concentration.

Claim 23

A method of decreasing hydrogen sulfide and total sulfur concentration of a gas comprising the steps of: introducing a gas with a first hydrogen sulfide concentration of a fragmented permeable mass of oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the gas with oxygen in the presence of the oil shale to yield gas having a second hydrogen sulfide concentration; and withdrawing such gas having the second hydrogen sulfide concentration from the fragmented permeable mass of oil shale, wherein the second hydrogen sulfide concentration is lower than the first hydrogen sulfide concentration.

Claim 26

A method of decreasing hydrogen sulfide concentration of a gas comprising the steps of: introducing a gas containing relatively higher hydrogen sulfide concentration to a fragmented permeable mass of oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the gas with oxygen in the presence of the oil shale to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 27

A method of decreasing hydrogen sulfide concentration of a gas comprising the steps of: introducing a gas containing relatively higher hydrogen sulfide concentration to a fragmented permeable mass of oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the gas with oxygen in the presence of the oil shale to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 32

A method for decreasing hydrogen sulfide concentration of a gas stream comprising the step of passing a gas containing relatively higher hydrogen sulfide concentration through a first in situ oil shale retort containing an explosively fragmented permeable mass of oil shale particles, while concurrently introducing a source of oxygen into said first retort to combine therein at a temperature up to about 650° F with said hydrogen sulfide, whereby the gas after passing through the first retort is of relatively lower hydrogen sulfide concentration than the gas before passing through the retort.

Claim 33

A method for decreasing hydrogen sulfide concentration of a gas stream comprising the step of passing a gas containing relatively higher hydrogen sulfide concentration through a first in situ oil shale retort containing an explosively fragmented permeable mass of oil shale particles, while concurrently introducing a source of oxygen into said first retort to combine therein at a temperature up to about 650° F with said hydrogen sulfide, whereby the gas after passing through the first retort is of relatively lower hydrogen sulfide concentration than the gas before passing through the retort.

Claim 35

A method of decreasing hydrogen sulfide concentration of a gas comprising the steps of: introducing a gas containing relatively higher hydrogen sulfide concentration to a fragmented permeable mass of particles containing raw oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the introduced gas with oxygen in the presence of the raw oil shale to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the fragmented permeable mass.

Claim 36

A method of decreasing hydrogen sulfide concentration of a gas comprising the steps of: introducing a gas containing relatively higher hydrogen sulfide concentration to a fragmented permeable mass of particles containing raw oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the introduced gas with oxygen in the presence of the raw oil shale to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the fragmented permeable mass.

Claim 39

A method of decreasing hydrogen sulfide concentration of gas in a first in situ oil shale retort in a subterranean formation containing oil shale by forming sulfur from the hydrogen sulfide, said first in situ retort containing a fragmented permeable mass of formation particles containing raw oil shale, which comprises the steps of: introducing gas containing relatively higher hydrogen sulfide concentration into the first retort; introducing oxygen containing gas into the first retort for reacting oxygen in the oxygen containing gas with hydrogen sulfide in the gas of relatively higher hydrogen sulfide concentration at a temperature less than about 650° F in the presence of raw oil shale to produce sulfur and to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas containing hydrogen sulfide; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the first retort.

Claim 40

A method of decreasing hydrogen sulfide concentration of gas in a first in situ oil shale retort in a subterranean formation containing oil shale by forming sulfur from the hydrogen sulfide, said first in situ retort containing a fragmented permeable mass of formation particles containing raw oil shale, which comprises the steps of: introducing gas containing relatively higher hydrogen sulfide concentration into the first retort; introducing oxygen containing gas into the first retort for reacting oxygen in the oxygen containing gas with hydrogen sulfide in the gas of relatively higher hydrogen sulfide concentration at a temperature less than about 650° F in the presence of raw oil shale to produce sulfur and to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas containing hydrogen sulfide; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the first retort.

Claim 44

A method for reducing the hydrogen sulfide concentration of an off gas from an in situ oil shale retort comprising the steps of: introducing the off gas to a fragmented permeable mass of raw oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the off gas with about one mole of oxygen per two moles of hydrogen sulfide in the off gas in the presence of the raw oil shale to produce sulfur and to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the off gas; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 45

A method for reducing the hydrogen sulfide concentration of an off gas from an in situ oil shale retort comprising the steps of: introducing the off gas to a fragmented permeable mass of raw oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the off gas with about one mole of oxygen per two moles of hydrogen sulfide in the off gas in the presence of the raw oil shale to produce sulfur and to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the off gas; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 48

A method of decreasing hydrogen sulfide concentration of a gas containing hydrogen sulfide and water comprising the steps of: introducing a gas containing water and relatively higher hydrogen sulfide concentration to a fragmented permeable mass of oil shale, wherein at least a portion of the oil shale has been treated to remove organic material prior to introducing the gas to the oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the introduced gas with oxygen in the presence of oil shale and water to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas; and withdrawing such gas having a relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 49

A method of decreasing hydrogen sulfide concentration of a gas containing hydrogen sulfide and water comprising the steps of: introducing a gas containing water and relatively higher hydrogen sulfide concentration to a fragmented permeable mass of oil shale, wherein at least a portion of the oil shale has been treated to remove organic material prior to introducing the gas to the oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the introduced gas with oxygen in the presence of oil shale and water to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the introduced gas; and withdrawing such gas having a relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 50

A method for reducing the hydrogen sulfide concentration of an off gas from an in situ oil shale retort, the off gas containing hydrogen sulfide, particulates, and hydrocarbon containing aerosols, comprising the steps of: introducing the off gas to a fragmented permeable mass of oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the off gas with oxygen in the presence of the oil shale to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the off gas; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.

Claim 51

A method for reducing the hydrogen sulfide concentration of an off gas from an in situ oil shale retort, the off gas containing hydrogen sulfide, particulates, and hydrocarbon containing aerosols, comprising the steps of: introducing the off gas to a fragmented permeable mass of oil shale; reacting at a temperature less than about 650° F hydrogen sulfide in the off gas with oxygen in the presence of the oil shale to yield gas having a hydrogen sulfide concentration relatively lower than the hydrogen sulfide concentration of the off gas; and withdrawing such gas having relatively lower hydrogen sulfide concentration from the fragmented permeable mass of oil shale.