Device and method for extracting carbon-containing substances from oil sand

Abstract

The invention relates to a device for extracting carbon-containing substances, in particular bitumen, from oil sands. The device comprises two separate steam circuits. The first steam circuit is a closed steam circuit, in which a steam turbine (3) is operating. The second steam circuit is an open steam circuit and is used for extracting carbon-containing substances, in particular bitumen, from oil sands. The steam turbine (3) comprises an intermediate steam removal facility (4), wherein the intermediate steam is used to evaporate the water/vapor in the second steam circuit via a heat exchanger. The invention further relates to a method for extracting carbon-containing substances by means of the previously described device.

Claims

1. A device for extracting carbonaceous substances from oil sands, the device comprising: at least two separate steam circuits, wherein a first steam circuit of the at least two separate steam circuits comprises at least one first steam generator and a steam turbine that is connected to the at least one first steam generator and has an intermediate steam extraction point, wherein a second steam circuit of the at least two separate steam circuits comprises at least one second steam generator, an injection pipeline, a production pipeline, and a water processing plant, wherein steam is introducible into an oil sand via the injection pipeline, the carbonaceous substances being dischargeable from the oil sand via the production pipeline, and a bitumen being separateable from water in the water processing plant, and wherein the intermediate steam extraction point of the first steam circuit is in functional communication with a first heat exchanger of the second steam circuit.

2. The device of claim 1, wherein the steam turbine is connected on an output side to a first generator for power generation, and wherein the device further comprises an electric/electromagnetic heater for heating the oil sands, the electric/electromagnetic heater being operateable with electric power that is generated by the first generator.

3. The device of claim 2, wherein the device further comprises at least one heat engine that is connected on an output side to a second generator for power generation, and wherein electric power that is generated by the second generator is useable for simultaneous or alternative heating of the oil sands by the electric/electromagnetic heater.

4. The device of claim 3, wherein the steam generation is carried out in the first steam circuit by a second heat exchanger, and wherein superheated exhaust gas of the at least one heat engine is used for steam generation in the first steam circuit.

5. The device of claim 3, wherein the at least one heat engine comprises a gas turbine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic and simplified view of one embodiment of a device for extracting carbonaceous substances.

DETAILED DESCRIPTION

(2) FIG. 1 shows an exemplary embodiment of a device for extracting carbonaceous substances (e.g., bitumen) from oil sands. The oil sands are located in deposits 14 in the ground. If the rock layer above the deposit 14 is not excessively large, the mining of the oil sands is carried out by open cast mining. After a specified depth of, for example, more than 60 m, the open cast mining is no longer economical, however, so that use is made of the in-situ process that is described in the description introduction.

(3) The device according to one or more of the present embodiments for such an in-situ process includes at least two separate steam circuits 1, 5 (e.g., a first steam circuit 1 and a second steam circuit 5). The first steam circuit 1 includes, for example, at least one first steam generator 2 and a steam turbine 3 that is connected to the first steam generator 2 and has an intermediate steam extraction point 4. The second steam circuit 5 includes at least one second steam generator (e.g., in the form of a first heat exchanger 7), an injection pipeline 8, a production pipeline 9, and a water processing plant 10. The injection pipeline 8 and the production pipeline 9 may extend horizontally inside the deposit 14 (not shown in FIG. 1). The injection pipeline 8 and the production pipeline 9 extend, for example, in parallel and typically at a distance of about 5 m to 10 m from each other. In the horizontal direction, the pipes extend inside the deposit 14 over a length of between several hundred meters and a few kilometers. Via the injection pipeline 8, steam may be introduced into the deposit 14 and consequently into the oil sand. The superheated steam provides a breaking up of the long-chain hydrocarbons and a reduction of the viscosity of the bitumen. By breaking up the long-chain hydrocarbons of the highly viscous bitumen and by reducing the viscosity, the bitumen becomes free-flowing. The free-flowing bitumen sinks towards the bottom in the process on account of gravitational force and may then be transported to the surface as a bitumen-water emulsion. For the transporting, simple oil lift pumps 15, for example, are suitable.

(4) The bitumen-water emulsion may then be processed in a corresponding processing plant 10 to form crude oil. The water of the bitumen-water emulsion is recovered in the processing plant 10 and fed again to the second steam generator 6 via a corresponding feedback line 16. The intermediate steam extraction point 4 of the first steam circuit 1 is in functional communication with the first heat exchanger 7 of the second steam circuit 5. This provides that the superheated steam is extracted from the intermediate steam extraction point, and thermal energy in the first heat exchanger 7 is released to the water/steam of the second steam circuit 5 and consequently provides evaporation of the water in the second steam circuit 5. During this, there is no direct contact between the water/steam of the first steam circuit 1 and the water/steam of the second steam circuit 5. The first steam circuit 1 is operated as a closed steam circuit. As a result of this, no contamination of the water/steam in the first steam circuit 1 may occur. Contamination of the water/steam of the first steam circuit 1 with bitumen is therefore excluded. As a result of this, the operational reliability of the device according to one or more of the present embodiments noticeably increases compared with the devices that are described in the prior art. The steam turbine and the associated auxiliary units and pipelines may be produced from simpler materials. As a result of this, the costs for the steam turbine may be reduced. The steam turbine 3 is connected on the output side to a first generator G1. The generator G1 generates electric power that serves directly for operating an electric/electromagnetic heater 11. The electric/electromagnetic heater also serves for heating the oil sand deposits. The electric/electromagnetic heater 11 is introduced in the deposit in addition to the injection and production pipelines. As a result of the additional electric/electromagnetic heater 11, a particularly efficient heating of the deposit is achieved. As a result of this, an efficient breaking up of the long-chain hydrocarbons and a substantial lowering of the viscosity of the bitumen are achieved. As a result of this, the deposit may be mined in a very efficient manner.

(5) The device also includes a heat engine in the form of a gas turbine 12 that is connected on the output side to a second generator G2. The generator G2 also generates electric power that may be used for operating the electric/electromagnetic heater 11. Provision may be made for switching that enables the electric/electromagnetic heater 11 to be operated either solely via the steam turbine 3, solely via the gas turbine 12, or via the gas turbine 12 and the steam turbine 3, or corresponding generators, at the same time. Depending on the required electric power, the gas turbine 12 may be correspondingly designed.

(6) The electric power that is generated by the generators G1 and G2 and not required may be additionally used for operating additional and auxiliary units of the plant or be fed into an electricity network.

(7) The steam generation in the first steam circuit is carried out in the exemplary embodiment by a second heat exchanger 13. The second heat exchanger 13 is fed by hot exhaust gas of the heat engine 12, and in this case, the hot exhaust gas passes through the second heat exchanger 13 in counterflow to the water/steam of the first steam circuit 1. The second heat exchanger 13 may be additionally heated by a fired boiler or the like.

(8) The method according to one or more of the present embodiments for extracting carbonaceous substances (e.g., bitumen) from oil sands by the previously described device is explained briefly below. Steam is generated in the first steam generator 2 in the first steam circuit 1 and fed to the steam turbine 3. A first portion of the steam is largely fully expanded in the steam turbine 3 and then condensed in an additional condenser 16 and fed to the first steam generator 2 via additional pumps 17, 18 and a degassing-/deaerating device 19. A second portion of the steam is extracted from the steam turbine 3 at the intermediate steam extraction point 4. The steam that is extracted from the intermediate steam extraction point 4 and has a higher temperature is fed back to the first steam generator 2 of the first steam circuit 1 via a first heat exchanger 7 of the second steam circuit 5. The steam flows, for example, through the first heat exchanger 7 in counterflow to the water/steam of the second steam circuit 5 and in the process releases a portion of the heat to the water/steam of the second steam circuit 5. As a result of this, steam is generated in the first heat exchanger 7 of the second steam circuit 5 and is introduced into the oil sand via the injection pipeline 8. The superheated steam heats the oil sand and provides a breaking up of the long-chain hydrocarbons of the carbonaceous substances and leads to a reduction of the viscosity. As a result of this, sinking of the bitumen-water emulsion occurs on account of gravitational force. The bitumen-water emulsion may be discharged via the production pipeline 9 and fed to a processing plant 10. A simple oil lift pump 15 is used for this purpose. In the processing plant 10, the bitumen is separated from the water. The bitumen may then be processed to form crude oil. The water that is separated from the bitumen is fed again to the first heat exchanger 7 and evaporated. Water that is lost in the process is replaced.

(9) The device according to one or more of the present embodiments is distinguished by two separate steam circuits, where a first steam circuit exists as a closed steam circuit and the steam turbine is operated within the closed steam circuit. The first, closed, steam circuit is not in communication with the carbonaceous substances so that contamination of the first steam circuit, and consequently contamination of the steam turbine, may not occur. As a result of this, the operational reliability of the steam turbine is increased and the use of high-quality materials may be dispensed with. As a result of this, a cost reduction results. The extraction of the carbonaceous substances from the oil sands is carried out in a second, open, steam circuit. In this circuit, it does not matter if residues of bitumen are present in the steam.

(10) The elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent of dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent. Such new combinations are to be understood as forming a part of the present specification.

(11) While the present invention has been described above by reference to various embodiments, it should be understood that many changes and modifications can be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.