This invention relates to recovering energy from fossil resources that contain mineral material combined with organic material that are found in nature in the form of various coals, oil shales, oil sands, etc. These fossil resources may be processed individually or in combination to optimize the recovery of the energy contained in them. By way of example, the present invention will be described in detail as it relates to the recovery of oil and gas from oil shale per se, since it contains large amounts of mineral material (around 80%) and by reference to the application ofthis invention to coal per se since the mineral material in coal generally does not exceed 15%. The invention will also be described in detail by using oil shale and coal in combination, with the aid of a process flow diagram.
In 1983 a U.S. patent was issued to the applicant bearing U.S. Pat. No. 4,376,033 which covers the recovery of shale oil from shale. This patent discloses the pyrolysis of oil shale by making use of electrical power in a plurality of cells within which the shale is contained and insulating the outer walls of the cells from one another. By means of induction, said walls are heated to cause thermal energy from the walls of the cells to effect the pyrolysis of the shale and result in the release of the oil from the shale in vapor form that leaves from the top of the cells.
The raw shale, after being pyrolized, takes the form of spent shale which is discharged from the bottom of the cells. This spent shale is further processed by compression into blocks to reduce the volume of the spent shale in order to facilitate its disposal within the mine whence the raw shale was excavated. Prior to the delivery of the blocks to the mine, a sealer is applied to the blocks to make them impervious to water in order to prevent the contamination of the surroundings where the blocks are stored.
In 2005, a U. S. patent was issued to the applicant bearing U.S. Pat. No. 6,911,058 B2 relating to the processing of coal. It covers the feeding of coal into a chamber which is equipped with a mechanical pusher which advances the coal within the chamber while an oxidant is injected from the discharge end of said chamber to combust a portion of the coal to generate thermal energy that devolatilizes the coal, producing a hydrogen-rich gas and a hot char which is subsequently gasified. The disadvantage of this reference is the massive pusher required to maintain the movement of the coal within said chamber.
Objectives
In the recovery of oil from oil shale, the biggest impediment towards exploitation of this vast resource is the solid spent shale that is generated after pyrolysis. Since the volume of the spent shale is quite large, very voluminous, and produces a serious negative impact to the environment, the main object of this invention is to overcome this serious and objectionable factor by providing a method and apparatus that converts the spent shale into a dense, non-leaching slag by melting it and then re-solidifying it into a vitreous material which may have useful applications.
Another object of this invention is to convert the residue in the spent shale which is in the form of carbon and certain residual hydrocarbons to a valuable, hot synthesis gas via gasification, the synthesis gas being hereafter referred to as “syngas.”
Still another object of this invention is to improve the transfer of heat into the raw shale during its pyrolysis by making use of the hot syngas to hydroretort the raw shale by directly contacting the hot syngas at the optimum temperature and residence time with the shale to result in increasing the overall efficiency of oil recovery from the shale.
Therefore, another object of the present invention is to provide a pressurized system to effect the movement of the gases through the various steps of the method.
Further, another object of the invention is to provide an integrated method and apparatus to conduct same comprising hydroretorting, gasification, and product distillation.
Further still, another object of the present invention is to substitute coal for oil shale to produce gas(es), liquids(s) or a combination of both.
Yet another object of the present invention is to supplement the raw shale with a carbonaceous material such as coal in order to increase the oil yield and also provide sufficient carbon as fuel to be adequate to melt the relatively large quantities of spent shale into a hot liquidus material hereinafter referred to as molten “slag.”
It is another object of the present invention to recover thermal energy from the molten slag.
It is still another object of the present invention to quench the molten slag in order to re-solidify it and thus obtain a non-leaching, vitreous frit.
It is therefore another object of the present invention to produce a shale oil vapor product via hydroretorting which is fractionated yielding various liquid fractions and a non-condensable gas.
It is further another object of the present invention to produce a hydrogen-rich gas as a by-product which is useful in the upgrading of the recovered oil and/or in the manufacture of synthetic natural gas hereinafter referred to as SNG.
It is yet another object of the present invention to produce a hydrogen-rich gas as a by-product which is converted to a liquid product to supplement the liquid product extracted from the shale.
Other objects of the invention will appear from the following description and appended claims.
Before explaining in detail the present invention, it is to be understood that this invention is not limited to the details of construction and the arrangement of the parts illustrated in the accompanying drawings, since the invention may possess other embodiments. Also it is to be understood that the phraseology or terminology herein contained is for the purpose of description and not limitation. Reference is now made to the accompanying drawings forming a part of this specification wherein like reference numerals designate corresponding parts in the various figures.
In
Referring to
Referring to
To initiate the start-up of the method, a burner marked by numeral 53 is provided and mounted at the top of gasifier 11. An array of injectors marked by numeral 54 is provided at various locations in gasifier 11 for the introduction of an oxidant which may be air or oxygen, but preferably oxygen which is moderated with steam to produce a hot syngas in gasifier 11; this syngas serves as a medium for directly heating the raw shale by introducing it at the top of hydroretort 10, as shown in
Gasifier 11 possesses two main ports: port 56 for the entry of the hot spent shale from hot lockhopper 17, and common port 18 for the flow of the spent shale in the form of a molten, vitreous slag together with the syngas, both being produced in gasifier 11. As secondary ports, port 57 is for the introduction of the flue gas from burner 53, ports 58 for the introduction of the gasification oxidant and steam from injectors 54, and port 59 for the introduction of the oxidant from lance 55.
Referring to
With respect to syngas exhaust 60, it includes gas conduit 61 and temperature control heat exchanger 62 which moderates the temperature of the syngas and generates high-pressure steam. Exhaust conduit 19 is provided for directing the moderated syngas to the top of hydroretort 10 shown in
With respect to HRSG 12, it comprises a bottom manifold 63 for feed water, with inlet 64 for water delivery into manifold 63, a top manifold 65 for steam collection, and an array of vertical pipes configured as a cage and marked by numeral 66 which interconnects manifold 63 to manifold 65. The delivery of high-pressure steam out of manifold 65 and into steam drum 26 is effected via conduit 67; high pressure steam out of steam drum 26 is effected via conduit 68.
With respect to slag quench 13, it comprises conical quench section 69 which is integrated to the bottom of HRSG 12, and water tank 30 to maintain a designated level of water within quench section 69. Conduit 70 communicates bottom of tank 30 to section 69. An exit port denoted by numeral 71 is provided at the top of HRSG 12 for the exhaust of the low-pressure steam generated when the molten slag is quenched in the pool of water contained in conical quench section 69. This low-pressure steam (via conduit 72) is delivered to conveyor 16 (shown in
With respect to lockhopper 31 and slag tank/drag conveyor 32, upper valve 73 and lower valve 74 are provided, with valve 73 controlling the quenched slag into lockhopper 31 from quench section 69, and valve 74 controlling the quenched slag out of lockhopper 31 and into slag tank/drag conveyor 32. Slag tank/drag conveyor 32 is known in the art and is briefly herein described. It consists of a tank within which a drag-chain conveyor is installed. The conveyor is configured to drag particulate matter from the bottom of the tank and elevate it on a slope prior to discharging it at the end of the slope. The slag containing tank is denoted by numeral 75, and its discharge chute is denoted by numeral 76.
Referring to
Referring now to
Numeral 90 represents a sorbent regenerator, and 91 represents a desulfurizer which is followed by a shift converter 92, a CO2 separator 93, and a methanator 94. Other components that are illustrated include a sulfur condenser 95, a regenerator gas cooler denoted by numeral 96, and compressors 97 and 98. In the event that pure hydrogen is to be made as a side stream, separator 99 is included; it is equipped with a compressor marked by numeral 100.
While the operation of the improved method and apparatus of the instant invention may be comprehended from the foregoing description, it is believed that the operation may further be explained as hereinafter set forth.
Operation
Referring again to
As shown, the moderated syngas enters at the top of hydroretort 10 and flows downward with the shale/coal combination in a co-current mode while heating both the shale and coal to efficiently pyrolize them and generate a vapor product which leaves hydroretort 10 as stream 20; it is thence directed to a distillation column such as fractionator 14 which produces various liquid fractions that are characterized as stream 21 for light naphtha, 22 for heavy naphtha, 23 for light gas oil, and 24 for atmospheric heavy gas oil. The distillation bottoms are directed to gasifier 11, via stream 111 to be recycled, and the non-condensable gases inclusive of the syngas used to hydroretort the shale/coal (stream 25) are directed to gas cleanup 91 to be treated by means of a catalytic sorbent to remove the sulfur in the gas. The treated gases leave gas cleanup 91 via stream 113 and flow into shift converter 92 where the hydrogen content is brought to a level of 3 H2 to 1 CO by reacting with steam supplied via stream 114. The shifted gas (stream 115) is next directed to separator 93 to separate the CO2 produced in shift converter 92, to thus form a CO2 stream marked by numeral 116, and treated feed gas suitable for methanation as stream 117. Stream 116 may be compressed to the desired pressure by means of compressor 97 to form stream 118 to make it ready for sequestration. Stream 117 may be split into stream 119 and stream 120 if hydrogen is to be made from the treated gas in addition to the SNG; in such a case, stream 120 is directed to gas separator 99 to form a CO stream marked by numeral 121 which is compressed by compressor 100 to form stream 122 that is recycled into gasifier 11, and a hydrogen stream marked by numeral 123.
With respect to stream 119, it is directed to methanator 94 where it is reacted with a catalyst to form synthetic natural gas of pipeline quality which leaves as stream 124, and water that leaves as stream 125.
With respect to the catalytic sorbent that treats the gas in reactor 91, it leaves reactor 91 as stream 126 when it is spent; it joins catalyst make up fed via stream 127 to form together solid stream 128 which is conveyed pneumatically by compressed carrier gas stream 129 by making use of compressor 98. Solid stream 128 is fed to sorbent generator 90 where the sorbent is regenerated with an oxidant (stream 130) which may be moderated with steam (stream 131); both of these streams form a joint stream 132 which enters regenerator 90. The off-gas from regenerator 90, stream 133 is cooled in heat exchanger 96 and exits as stream 134 prior to entering sulfur condenser 95 where elemental sulfur is maintained in a molten state.
Within condenser 95, the non-condensable part of the off-gas and the molten sulfur are separated, and both leave as separate streams: stream 135 as sulfur, and stream 136 as a transport gas which, after compression in compressor 98, conveys the spent sobriety catalyst from the bottom of desulfurizer 91 to the top of regenerator 90. The sorbent catalyst which is regenerated flows from regenerator 90 into desulfurizer 91 by gravity via stream 137. The carrier gas (stream 129) which transports the spent sorbent from the bottom of desulfurizer 91 to the top of regenerator 91 after disengagement from the spent sorbent is exhausted into gasifier 11 to be recycled (stream not shown).
Using
Reference is now made to
Referring to
As the hot spent shale descends within gasifier 11 and syngas is generated by the reaction of carbon with oxygen and steam, both the spent shale and the syngas are directed to flow co-currently towards bottom 48 of gasifier 11, with the spent shale changing state from a solid to a semi-plastic thence to a liquid slag while both the syngas and the liquid slag flow from gasifier 11 via port 18. To maintain port 18 open, the syngas and the molten spent shale which takes the form of a slag, flow together through port 18 which serves as a common port. Lance 55 serves as a means to insure that common port 18 remains open; it supplies an oxidant such as oxygen via port 59 to combust a small portion of the syngas and maintain the temperature of bottom 48 of gasifier 11 above the melting point of the slag.
As the syngas and slag flow through common port 18, the syngas is separated from the slag by leaving gasifier 11 through port 60, while the slag falls freely into water pool 69 to be fully quenched, and re-solidifies into a grit as it shatters when it comes in contact with the water. Recovery of heat from the molten slag is effected by HRSG 12, and quench water make-up is furnished from tank 30.
Referring to
The syngas leaving gasifier 11 via port 60 is moderated in temperature within heat exchanger 62; thence it is directed to hydroretort 10 (shown in
Using this invention with coal per se, with such coal being low in ash, the use of HRSG 12 may be obviated since the benefit derived from a HRSG would be minimal. Justification of whether to exclude or include HRSG 12 is to be examined on a case-by-case basis by giving consideration to economics. Further, whether the use of the oxidant is pure oxygen or air, or a combination thereof in gasifier 11 and in lance 55 is an option to be considered on a case-by-case basis, depending upon the ultimate product(s) to be made. Additionally, consideration is to be given whether or not fractionator 14 is to be used in the processing of coal per se. The invention may also be used to produce liquids from the syngas, in whole or in part, by employing known technologies such as the Fischer Tropsch process.
It is submitted that the presentation made herein discloses a method and apparatus which can process fossil resource(s) such as coal, oil, shale, oil sand, etc., for producing abundant energy efficiently, and in an environmentally acceptable manner.