WO2012038424A2

WO2012038424A2 - Apparatus for heating the ground

Info

Publication number: WO2012038424A2
Application number: PCT/EP2011/066318
Authority: WO
Inventors: Michael Koolman; Bernd Wacker
Original assignee: Siemens Aktiengesellschaft
Priority date: 2010-09-24
Filing date: 2011-09-20
Publication date: 2012-03-29
Also published as: DE102010041329A1; WO2012038424A3

Abstract

The invention relates to an apparatus for heating the ground (1) with at least one inductive heater. In this case, at least one conductor loop (2), which runs at least partially in the ground (1) and has sectionally compensated inductance, is fed electrical energy via a convertor unit (3; 3'). The electrical energy is generated by at least one energy convertor (4), which converts a regenerative energy into electrical energy. The convertor unit (3; 3') converts the electrical energy generated by the energy converter (4) directly into a medium-frequency or high-frequency electrical energy.

Description

description

Device for heating soil

The invention relates to a device for heating soil with at least one inductive heating, wherein at least one at least partially extending in the ground conductor loop is fed with partially compensated inductance via an inverter unit with electrical energy.

Large parts of the world's oil reserves are in the form of oil sands. Oil sands are a mixture of rocks, clay, sand, water and bitumen or other heavy oils. In the following, merely representative of heavy, heavy oils or generally long-chain hydrocarbons is to be spoken only of bitumen, which with a viscosity of typically API 5 deg. up to 15 deg. occurring in a warehouse. The bitumen can be converted by means of further process steps into synthetic crude oil. Oil sands are partly located in strata of shallow depth, which are open to the open pit. But there are also large oil sands deposits that are not accessible to the open pit. Typically, the in-situ recovery is made from depths of 60 m and lower, as the degradation of the overburden then no longer seems worthwhile.

One method typically used to exploit such deposits is Steam Assisted Gravity Drainage.

(SAGD). Here, the present in a reservoir bitumen ^¬ men is heated by hot steam and the deposit made permeable by the vapor pressure. In this way, the Vis ^¬ viscosity of the bitumen is reduced, so that it can be promoted in liquid form and faster from the deposit. The change in viscosity of the bitumen occurs through a temperature increase.

Besides the most commonly used SAGD are also more Method for heating soil known, such as the so-called "Toe To Heel Air Injection" (THAI).

In addition to the promotion of bitumen, there are also other applications in which a warming of soil is useful or necessary. Thus, for example, the Austrei ^¬ exercise or microbial degradation of pollutants from or in contaminated soil can be enabled or accelerated by heating.

However, the above methods are associated with high steam consumption or partial consumption of hydrocarbons as fuel.

Therefore were electrical and / or electromagnetic drive Ver ^¬ developed for heating the soil in which electrical energy is converted ^¬ converts directly or indirectly into heat. In addition to purely resistive and inductive methods methods are known ge ^¬ been in the recent past.

From DE 10 2007 036 832 AI a device for in-situ recovery of a hydrocarbonaceous substance reducing its viscosity from an underground reservoir is known, which at least one leading out of the deposit production pipeline and at least two electrodes of an inductive and resistive against at least parts of Deposit has effective electrical heating.

From DE 10 2007 040 605 B3 a device for "in situ" promotion of bitumen or heavy oil from oil sand deposits is known as a reservoir, wherein the reservoir with heat ^¬ energy to reduce the viscosity of the bitumen or heavy oil is applied. For this purpose, an electrical / electromagnetic heating, and a conveyor pipe for carrying away of the liquefied bitumen or heavy oil are at least vorgese ^¬ hen. At a given depth of the reservoir are at least two linearly extended conductor out parallel in a horizontal direction out ^{¬ ¬} , wherein the ends of the conductors are electrically conductively connected inside or outside the reservoir and together form a conductor loop. The conductor loop realizes a given complex resistance. The two conductors are connected to an exter ^¬ NEN alternator for electrical power outside of the reservoir. In addition, the inductance of the conductor loop is partially compensated.

However, the need for electrical energy to mobilize viscous hydrocarbons or even to remove pollutants in contaminated soil can be significant. Nowadays, electrical energy from a conventional 50 Hz or 60 Hz power grid is usually used. However, the prerequisite is that the power grid with sufficient power is available, which is often not the case for geographically remote facilities, so that the electrical energy over long distances with high loss afflicted must be brought to the system.

With the solution of this problem, the DE 10 2008 047 219 AI deals. From this, a method for the extraction of bitumen and / or heavy oil from an underground deposit is known, in which the viscosity of the heavy oil 'in situ' he ^{¬ is} lowered, including the deposit energy in the form of vapor flowing through the deposit on the one hand and electrical power to the inductive and / or resistive heating, on the other hand. In this case, the energy for generating the steam and equally for electrical heating is generated decentrally at the location of the conveyors. For this purpose, for loading ^¬ drive an industrial turbine with coupled generator uses a part of the produced bitumen and / or heavy oil, on the one hand of the industrial turbine down- stream generator supplies the electric power for heating and on the other hand, an industrial turbine supplied arrange ^¬ ter boiler to produce steam by evaporation of water serves. However, such on-site power generation facilities often operate only suboptimal due to the relatively low power levels. In addition, fossil energy sources produced at the production by the usage-even appreciable C0 ₂ ~ quantities.

For example, bitumen production typically requires 8 to 12 MW of steam and / or 1 to 2 MW of electrical energy per production well. For a typical

50,000 bl / day of bitumen production plant thus become 50 to 100 MW of energy required for purely electrical heating, which means the electrical supply via a high voltage line, with e.g. 110 kV, provided that no on-site power generation is provided.

The invention has for its object to provide a device for heating soil with at least one inductive heating, which is energy efficient and pollutant operated.

This object is achieved by a device for Erwär ^¬ mung of soil with at least one inductive heating dissolved in an at least partially ^stabilized rich extending in the earth conductor loop with partially compensated lized inductance via a converter unit with electrical ^¬ shear energy is supplied at least. According to the invention elekt ^¬ innovative energy is generated by at least a power converter having a regenerative energy into electrical energy wan ^¬ punched. The inverter unit thereby converts the electrical energy converters produced by the energy directly into a ^¬ with medium- or high-frequency electrical energy. The electrical energy is advantageously in a range of 1 kHz to 300 kHz. Through the use of renewable energy sources, such as

Wind or solar radiation, the C0 ₂ load at the production site is significantly reduced. In addition, the direct conversion of electrical energy into required by the usual intermediate step of feeding into a conventional 50 Hz or 60 Hz power grid, avoided.

The generation of electrical energy from renewable energy sources is not constant, but is subject to strong fluctuations. This initially against the use of renewable energy sources-speaking disadvantage is compensated in the apparatus according to the invention characterized in that in the soil or the reservoir converted into heat electrical energy is stored in the ground. As long as energy is supplied, the temperature in the ground or the reservoir increases exponentially. Conversely, the temperature also decreases exponentially by heat conduction into the subterranean masses as soon as the energy supply is interrupted, but as long as the duration or amount of the energy supply is greater than the duration of the lack of energy supply the temperature of the soil or of the reservoir as a whole increases. The soil or reservoir thus acts as a heat storage with the result that the viscosity of the ^hydrocarbons to be pumped ^¬ decreases or increases the temperature of the expelled contaminants. The device according to the invention is easy to control with regard to temperature maintenance and thus also pressure guidance in the reservoir.

According to one embodiment of the invention, the energy converter comprises at least one wind turbine known per se, which has a rotor which is mechanically coupled to an alternator. A particularly good groove ^¬ utilization factor arises there when the wind turbine is operated in Gleitfrequenzbetrieb.

In an alternative embodiment, the energy converter is designed as a solar thermal power plant. The ^per se known solar thermal power plant has at least one industrial turbine, in the form of a gas or steam turbine, which is mechanically coupled to an alternator. The use of a solar thermal power plant provides the Mög ^¬ friendliness, generated for operation of the industrial turbine What ^¬ serdampf partially decouple to learn about a vapor, such as SAGD, in addition to heat the soil. Specifically, partially processed water vapor, in particular at a temperature of 200 ° C to 250 ° C, taken from the industrial turbine and introduced into the soil (1). In this way, a hybrid system is created which heats the soil both inductively and with the aid of superheated steam. This offers the particular advantage that the water vapor ^¬ due to the presence in solar thermal power plants typically night memory, for example can be generated in the form of a phase change memory with salt, around the clock. The continuous production of steam and electricity that is possible in this way means that the customer does not have to be designed for top performance.

As an alternative to using a solar thermal power plant, solar energy can also be used by using at least one photovoltaic module.

Advantageously, the power generator and consumer of the device according to the invention form a stand-alone grid. This one is independent of existing networks and can dispense in particular with the supply of high voltage lines.

To avoid losses due to energy transfer, it is also advantageous to arrange the energy converter decentralized in the vicinity of the soil to be heated.

According to a particularly simple embodiment of the converter unit, it has an intermediate circuit capacitor and an inverter connected downstream of the intermediate circuit capacitor. The energy converter comprises at least one Indust ^¬ rieturbine (solar thermal power plant) or a rotor (wind turbine), which are mechanically coupled to an alternating current generator ^¬ is the DC link capacitors Gate according to another embodiment of the invention, a rectifier, in particular in the form of a bridge rectifier, upstream.

Another embodiment of the invention provides that the output frequency of the converter unit is tuned to a resonant frequency of the conductor loop.

Since the conductor loop has a high self-inductance, a partial compensation is provided. Such a compensation is described in DE 10 2007 040 605 B3, which is fully included in the present application for the purpose of disclosure. By adjusting the output frequency of the converter unit to a resonance frequency of the conductive loop in an integrated line com pensation ^¬ can be realized.

Further features and advantages of the invention will become apparent from exemplary embodiments, which are explained below with reference to the drawings. Add:

1 is a schematic representation of a first embodiment of a device according to the invention for heating soil,

Fig. 2 is a schematic representation of a second embodiment of a device according to the invention for heating soil and

Fig. 3 is a schematic representation of a third embodiment of an inventive device for heating soil.

In the figures, identical or functionally identical compo nents ^¬ are each marked with the same reference numerals

The first embodiment shown schematically in FIG. 1 of a device according to the invention for heating natural gas. 1 includes an inductive heating, wherein a partially running in the soil 1 conductor loop 2 is fed via a Umrich ^¬ tereinheit 3 with electrical energy. The In ^¬ productivity of the loop is partially compensates. Suitable compensation methods with the aid of Se ^¬ rien- or transverse capacitances are described in DE 10 2007 040 605 B3. Is a Eignart in an integrated into the line of the conductive loop 2 compensation that must be off ^¬ tuned output frequency of the inverter unit 3 to a resonance frequency of the loop. 2 The signified ^¬ tet that the conductive loop 2 may be operated at that frequency, is wel ^¬ che typically in a range of 1 kHz to 300 kHz.

The electrical energy for feeding the conductor loop 2 is generated by an energy converter 4 in the form of one or more photovoltaic modules 5. The photovoltaic module 5 um ^¬ summarizes several solar cells and converts the light of the sun directly into electrical energy. The inverter unit 3 comprises an intermediate circuit capacitor 6 and the intermediate circuit capacitor 6 connected downstream of the inverter 7, and converts the electrical energy generated by the energy converter 4 directly in a medium or high-frequency elekt ^¬ innovative energy in the range of 1 kHz to 300 kHz. Due to the direct conversion of the electrical energy of the energy converter 4 ^¬ without the usual upstream feed to a conventional 50 Hz or 60 Hz mains associated energy losses are avoided. Advantageously, the power generator forms, so that the device can be operated independently of a mains power source in the form of over the inverter unit 3 to the photovoltaic module 5 is castle ^¬ NEN conductor loop 2, a stand-alone grid in the form of the photovoltaic module 5 and the power consumers. Is the energy converter 4 decentrally arranged in the vicinity of the soil to be heated, 1, no energy transfer ^¬ transmission to the site is required, so that energy loss caused thereby can be avoided. An alternative embodiment of a device according to the invention is shown schematically in FIG. This embodiment differs from the embodiment shown in FIG. 1 in that solar energy is used instead of solar energy, but wind energy is used as the regenerative energy source. Consequently, the energy converter 4 according to this ^{embodiment is designed} as a wind turbine 20, which converts the kinetic energy of the wind into electrical energy. The wind turbine 20 in this case comprises at least one rotor, eg in the form of a wind turbine 21 wherein the motion ^¬ energy of wind flow acting on the rotor blades, thereby causing the rotor to rotate. The rotor then passes the rotational energy to a preferably three-phase AC generator 22, which converts the rotational energy into electrical energy.

In this case, the inverter unit 3 'has a ^{rectified ¬} judge 23, which is connected upstream of a ^DC link capacitor 6'. To the DC link capacitor 6 'is followed in this imple mentation form an inverter 7'. The rectifier 23 may, for example, a bridge rectifier, in the case of a three Wechselstromgenera ^¬ tors 22 therefore be designed as a six-pulse rectifier.

In order to utilize the wind power plant 20 as highly as possible at ^different wind strengths and efficiently, it is advantageously operated in sliding frequency operation. FIG. 3 shows a further embodiment of the invention. Analogous to the imple mentation form according to Figure 1, solar energy is used as regenerative energy ^¬ source even in this ^imple mentation. In contrast to the first embodiment, however, no photovoltaic module but a solar thermal power plant 30 is used as energy converter.

The solar thermal power plant 30, which is shown in greatly simplified form in FIG. 3, comprises a solar field 31, in which the solar radiation is concentrated and converted into heat energy. The solar field 31 may include, for example, parabolic trough collectors, Fresnel collectors, solar towers or paraboloidal mirror collectors. In addition, a heat storage 32 - often referred to as night storage, for example in the form of a phase change memory with salt, vorgese ^¬ hen, in which the heat energy generated can be cached. Heat energy from the solar field 31 or the heat storage 32 is discharged in a steam generator 33 to a heat transfer medium in the form of water, which is vaporized and introduced via a first steam line 34 into a steam turbine 35 as working fluid. The steam turbine 35 is coupled mecha nically ^¬ preferably to a three-phase Wechselstromgenera ^¬ gate 22 '. In the steam turbine 35, the working fluid is relaxed, then again fed in a condenser 36 ver ^¬ liquefied and a return line 37 to the steam generator 33rd

The device according to the invention according to FIG. 3 is used, for example, in the context of "in situ" production of bitumen and / or heavy oil. Accordingly, an apparatus for Se ^¬ are groomed of the conveyed via a conveyor line 38 bitumen / heavy oil from the recirculated water is present, which is designated by the reference numeral. 39 To this device 39 is a unit 40 connected to the treatment and refurbishment of the recycled water. From the unit 40, the treated water is then fed back to the steam generator 33. A solar thermal power plant also offers the possibility of hybrid operation. In this case, the steam generated in the steam generator 33 can also be used directly to heat the soil 1, in addition to generating electrical energy via the steam turbine 34 and the alternator 22 '. This may be concretely in the form of a SAGD process, he ^¬ follow, for example, and is indicated in figure 3 by a second vapor pipe 41, which steam generator 33 with a laid in the ground 1 steam into ector connects 42nd The respective ones Flow directions of the steam are predetermined by appropriate Venti ^¬ le.

In conventional solar thermal power plants, the steam is heated to temperatures of 400 ° C to 450 ° C. For the introduction of steam in a SAGD production scheme, however, 200 ° C to 250 ° C are already sufficient. In order to achieve a controllable optimal hybrid scheme, therefore, a steam ^{extraction ¬ is provided} by a connecting line 43. The steam taken therefrom is partially processed and the residual steam energy is - instead of further relaxation in the steam turbine 35 and liquefaction in the condenser 36 - fed via the connecting line 41 to the injector 42. The soil 1 assumes the function of the capacitor. The converted with the high quality steam in the turbine energy part is converted in the generator 22 'in current, which is supplied to the conductor loop 2.

In this way, the energy contained in the steam is fully exploited ^¬ constantly, which increases the primary energy utilization ratio of about 40% up to 90%.

Claims

claims

1. A device for heating soil (1) with at least one inductive heating, wherein at least one at least partially in the soil (1) extending conductor loop (2) with partially compensated inductance via a Um ^¬ judge unit (3, 3 ') with electrical energy is fed, characterized in that the electrical energy is generated by at least one energy converter (4), which converts a regenerative energy into electrical energy, and the inverter unit (3; 3 ') the electrical energy generated by the energy converter (4) directly in a medium or high frequency electrical energy, in particular in the range of 1 kHz to 300 kHz, converts.

2. Apparatus according to claim 1, characterized in that the energy converter (4) converts wind energy or solar energy into electrical energy.

3. A device according to claim 2, characterized in that the energy converter (4) comprises at least one wind turbine (20) having a rotor (21) which is mechanically coupled to an alternator (22).

4. Apparatus according to claim 3, characterized in that the wind turbine (20) is operated in Gleitfrequenzbetrieb.

5. The device according to claim 2, characterized in that the energy converter (4) is designed as a solar thermal power plant (30) having at least one industrial turbine (35) which is mechanically coupled to an alternator (22 ').

6. Apparatus according to claim 5, characterized in that in the solar thermal power plant (30) water vapor for driving the industrial turbine (35) is generated and a partially from ^{¬ processed} steam, in particular with a temperature from 200 ° C to 250 ° C, taken from the industrial turbine and introduced into the soil (1).

7. The device according to claim 2, characterized in that the energy converter (4) comprises at least one photovoltaic module (5).

8. Device according to one of the preceding claims, characterized in that power generator and consumer of the device form a stand-alone grid.

9. Device according to one of the preceding claims, characterized in that the energy converter (4) is arranged decentrally in the vicinity of the soil to be heated (1).

10. Device according to one of the preceding claims, characterized in that the converter unit (3; 3 ') egg ^¬ nen intermediate circuit capacitor (6; 6') and the intermediate circuit capacitor (6; 6 ') downstream inverter (7; 7' ).

11. The device according to claim 10, characterized in that the energy converter (4) at least one industrial turbine (35) or a rotor (21) which are mechanically coupled to an alternator (22; 22 ') and the inverter unit (3') a rectifier (23), in particular bridge rectifier, an intermediate circuit capacitor (6 ') connected downstream of the rectifier (23) and an inverter (7') connected downstream of the intermediate circuit capacitor (6 ').

12. Device according to one of the preceding claims, characterized in that the output frequency of the Umricht- tereinheit (3; 3 ') is tuned to a resonant frequency of the conductor loop (2).