The present disclosure relates generally to environments and applications that use turbo-shaft turbine engines as the prime mover to rotate a load. The present disclosure will primarily relate to the high pressure pumping industry, particularly to pump systems and methods for hydraulic fracturing.
Fracturing is an oilfield operation that stimulates production of hydrocarbons, such that the hydrocarbons may more easily or readily flow from a subsurface formation to a well. For example, a fracturing system may be configured to fracture a formation by pumping a fracturing fluid into a well at high pressure and high flow rates. Some fracturing fluids may take the form of a slurry including water, proppants, and/or other additives, such as thickening agents and/or gels. The slurry may be forced via one or more pumps into the formation at rates faster than can be accepted by the existing pores, fractures, faults, or other spaces within the formation. As a result, pressure builds rapidly to the point where the formation may fail and may begin to fracture. By continuing to pump the fracturing fluid into the formation, existing fractures in the formation are caused to expand and extend in directions farther away from a well bore, thereby creating flow paths to the well bore. The proppants may serve to prevent the expanded fractures from closing when pumping of the fracturing fluid is ceased or may reduce the extent to which the expanded fractures contract when pumping of the fracturing fluid is ceased. Once the formation is fractured, large quantities of the injected fracturing fluid are allowed to flow out of the well, and the production stream of hydrocarbons may be obtained from the formation.
Prime movers may be used to supply power to a plurality of fracturing pumps for pumping the fracturing fluid into the formation. Traditionally, these high pressure, high volume pumping applications use diesel reciprocating engines to drive each of the plurality of reciprocating piston pumps in a system to deliver fluid to subsurface geological formations and fracture these formations to release the hydrocarbons for production. Also, a plurality of gas turbine engines may each be mechanically connected to a corresponding fracturing pump and may be operated to drive the corresponding fracturing pump. A fracturing unit may include a gas turbine engine or other type of prime mover and a corresponding fracturing pump, as well as auxiliary components for operating and controlling the fracturing unit, including electrical, pneumatic, and/or hydraulic components. The gas turbine engine, fracturing pump, and auxiliary components may be connected to a common platform or trailer for transportation and set-up as a fracturing unit at the site of a fracturing operation, which may include up to a dozen or more of such fracturing units operating together to perform the fracturing operation. In order to supply electrical, pneumatic, and/or hydraulic power for operation of the auxiliary components, an additional prime mover may be used.
In the field of hydraulic fracturing or fracking, the use of conventional diesel engines may be replaced with turbine engines to either directly drive a pump from the turbine output shaft or use the turbine to generate electrical power and distribute that power to electrical motors directly connected to pumps (e.g., electrical fracking) for the present disclosure. The replacement of reciprocating diesel engines with turbine engines, for example, may allow reduction in space and weight conventionally required by a prime mover as well as an increase in power density, thereby allowing greater values of shaft horse power (SHP) and torque to be generated and resulting in a reduction of fracturing trailers required to generate hydraulic horse power (HHP) demand.
A turbine engine also may have a reduction gearbox connected to it, or used in association with it, to allow for high speed rotation of a turbine output shaft to be reduced to a useable speed while still utilizing maximum power and torque. In fracturing applications, for example, the ratio of reduction for the high speed gearbox may be as high as a 11:1 reduction ratio as understood by those skilled in the art.
In the disclosure, Applicant has recognized that the replacement of reciprocating diesel engines with turbine engines may not eradicate requirements or needs for auxiliary systems onboard a fracturing trailer. The turbine engine still requires power to be delivered to fuel systems and lubrication systems as well as electrical and instrumentation devices. In addition to the turbine power requirements, other installed machinery onboard a fracturing trailer requires external power to drive lubrication systems, cooling systems, pumps and associated electrical devices. Some machinery and components may include the reciprocating fracturing pumps and the reduction gearbox. Currently these auxiliary support systems are powered using hydraulics or electrical power generation that includes a reciprocating diesel engine being directly connected to a hydraulic pump or an assembly of hydraulic pumps or an electrical generator. The assembly of these systems may be expensive, complicated, space consuming and heavy, which all contribute to building and compliance difficulties of hydraulic fracturing trailers according to government and industry standards.
Accordingly, in the disclosure, Applicant has recognized that there is a need for an efficient, compact power generation system to be used onboard a turbine driven hydraulic fracturing pumping trailer that may use turbine waste energy to assist in powering trailer auxiliary functions and allowing for recovered energy to be stored and used when needed.
In an embodiment, for example, a hydraulic fracturing power generation system, positioned onboard a hydraulic fracturing trailer assembly, includes a high-power hydraulic fracturing generation assembly having a turbine engine mounted to the hydraulic fracturing trailer assembly, a reduction gear box connected to the turbine engine and mounted to the hydraulic fracturing trailer assembly, a drive shaft connected to the reduction gear box and mounted to the hydraulic fracturing trailer assembly, and a turbine engine exhaust diffuser section mounted to the hydraulic fracturing trailer assembly and connected to the turbine engine, a reciprocating plunger pump connected to the drive shaft and mounted to the hydraulic fracturing trailer assembly, and a thermoelectric power generation assembly mounted to the hydraulic fracturing trailer assembly. The thermoelectric power generation assembly includes a turbine engine exhaust stack assembly mounted to the hydraulic fracturing trailer assembly and connected to the turbine engine exhaust diffuser section, a set of thermo-electric generator (TEG) sub-assemblies connected to the turbine exhaust stack sub-assembly to generate electric power responsive heat from the exhaust stack sub-assembly, and a power storage and distribution source mounted to the hydraulic fracturing trailer assembly to store and distribute power generated from the set of TEG sub-assemblies across the hydraulic fracturing trailer assembly. The power storage and distribution source, for example, may include a set of batteries, and the system also may have a diesel engine alternator mounted to the hydraulic fracturing trailer assembly and connected to the set of TEG sub-assemblies to enhance production and distribution of electrical power across the hydraulic fracturing trailer assembly. The system additionally may have a turbine engine starter motor mounted to the hydraulic fracturing trailer assembly so that the set of TEG assemblies operatively charges the power source, e.g., the set of batteries, thereby to enhance supply of power to the turbine engine starter motor for starting the turbine engine. In embodiments, the turbine engine, for example, may be a dual shaft turbine engine with an exhaust stack assembly equipped with TEGs that are then connected to an energy storage device, and from that storage device the energy is distributed around the fracturing trailer as a source of power.
An embodiment of a method to generate thermoelectric power for a hydraulic fracturing trailer assembly having a high-power hydraulic fracturing generation assembly positioned thereon, for example, may include operating a high-power turbine engine of the power generation assembly when adjacent a fracturing well site so as to produce exhaust gas therefrom, supplying the exhaust gas from the high-power turbine engine into a turbine engine exhaust stack assembly, and generating thermoelectric power from a set of thermoelectric generation (TEG) assemblies responsive to heat from the exhaust gas in the turbine engine exhaust stack assembly so as to supply power to a power storage and distribution source associated with the hydraulic fracturing trailer assembly. The method also may include operating a diesel engine alternator when connected to the set of TEG assemblies to enhance production and distribution of electrical power across the high-power hydraulic fracturing generation assembly. In embodiments of the disclosure, the turbine engine exhaust stack assembly may include an exhaust stack housing and a TEG housing mount assembly, and the set of TEG assemblies may be mounted to the exhaust stack housing via the TEG housing mount assembly so that the TEG assemblies receive heat from the turbine engine exhaust stack assembly when mounted to the exhaust stack housing. The method further may include controlling power levels associated with components of the high-power hydraulic fracturing generation assembly via a controller and the set of TEG assemblies.
In another embodiment, an assembly of thermo-electric generators (TEGs) may be installed on the exhaust stack assembly of a dual shaft turbine engine, for example, but in addition to the TEGs in place, the energy recovery system is used in conjunction with a solar energy recovery assembly that includes TEGs, energy storage devices, solar panels, and electrical circuit protection that is then distributed around a fracturing trailer. In still another embodiment, a method for storing the generated power on a separate trailer is disclosed. The energy storage trailer would include battery bank systems, circuit protection components, electrical switch gear as well as related electrical controlling components to monitor system variables.
The present disclosure may be more readily described with reference to the accompanying drawings, which are included to provide a further understanding of the embodiments of the present disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure, and together with the detailed description, serve to explain principles of the embodiments discussed herein. According to common practice, the various features of the drawings discussed below are not necessarily drawn to scale. Dimensions of various features and elements in the drawings can be expanded or reduced to more clearly illustrate embodiments of the invention.
The disclosure is described in various embodiments in the following description with the reference to the figures, in which like numbers and text represent the same or similar elements. Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. As used herein, the term “plurality” refers to two or more items or components. The terms “comprising,” “including,” “carrying,” “having,” “containing,” and “involving,” whether in the written description or the claims and the like, are open-ended terms, i.e., to mean “including but not limited to,” unless otherwise stated. Thus, the use of such terms is meant to encompass the items listed thereafter, and equivalents thereof, as well as additional items. The transitional phrases “consisting of” and “consisting essentially of,” are closed or semi-closed transitional phrases, respectively, with respect to any claims. Use of ordinal terms such as “first,” “second,” “third,” and the like in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish claim elements.
The described features, structures, or characteristics of the disclosure may be combined in any suitable manner in one or more embodiments as will be understood by those skilled in the art. In the following description, numerous specific details are recited to provide a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the disclosure may be practiced without one or more of the specific details, or with other methods, components, materials and so forth. In other instances, well known structures, materials, or operations are not shown or described in details to avoid obscuring aspects of the disclosure.
The disclosure includes a turbine engine pump assembly 100 (see
As illustrated in
In an embodiment, a hydraulic fracturing power generation system 80, positioned onboard a hydraulic fracturing trailer assembly 90, includes a high-power hydraulic fracturing generation assembly 100 having a turbine engine 120 mounted to the hydraulic fracturing trailer assembly 90, a reduction gear box 150 connected to the turbine engine 120 and mounted to the hydraulic fracturing trailer assembly 90, a drive shaft 170 connected to the reduction gear box 150 and mounted to the hydraulic fracturing trailer assembly 90, and a turbine engine exhaust diffuser section 160 mounted to the hydraulic fracturing trailer assembly 90 and connected to the turbine engine 120, a reciprocating plunger pump 300 connected to the drive shaft 170 and mounted to the hydraulic fracturing trailer assembly 90, and a thermoelectric power generation assembly 400 mounted to the hydraulic fracturing trailer assembly 90. The thermoelectric power generation assembly 400 includes a turbine engine exhaust stack assembly 45 mounted to the hydraulic fracturing trailer assembly 90 and connected to the turbine engine exhaust diffuser section 160, a set of thermo-electric generator (TEG) sub-assemblies 420, 430, 440 connected to the turbine exhaust stack assembly 45 to generate electric power responsive heat from the exhaust stack assembly 45, and a power storage and distribution source 510 mounted to the hydraulic fracturing trailer assembly 90 to store and distribute power generated from the set of TEG sub-assemblies 420, 430, 440 across the hydraulic fracturing trailer assembly 90, as shown in
The power storage and distribution source 510, for example, also may include a set of batteries 520, and the system 80 also may have a diesel engine alternator 260 mounted to the hydraulic fracturing trailer assembly 90 and connected to, or otherwise in electrical communication with, the set of TEG sub-assemblies 420, 430, 440 to enhance production and distribution of electrical power across the hydraulic fracturing trailer assembly 90. The system 80 additionally may have a turbine engine starter motor 270, as will be understood by those skilled in the art, mounted to the hydraulic fracturing trailer assembly 90 so that the set of TEG assemblies 420, 430, 440 operatively charges the power source 510, e.g., the set of batteries 520, thereby to enhance supply of power to the turbine engine starter motor 270 for starting the turbine engine 120. In embodiments, the turbine engine 120, for example, may be a dual shaft turbine engine with an exhaust stack assembly 45 equipped with the TEGs 420, 430, 440 that are then connected to an energy storage device 510, and from that storage device 510 the energy is distributed around the fracturing trailer 90 as a source of power.
Embodiments of a thermoelectric power generation system further may include an electrical controller 600 positioned in electrical communication with the set of TEG sub-assemblies 420, 430, 440 to control and monitor power levels of components associated with the hydraulic fracturing power generation system 80 via the TEG sub-assemblies. Also, the high-power hydraulic fracturing generation assembly 100 still further may include a turbine engine starter motor 270 mounted to the hydraulic fracturing trailer assembly 90, and the set of TEG sub-assemblies 420, 430, 440 may be positioned operatively to charge the set of batteries 520 to power the turbine engine starter motor 270 for starting the turbine engine 120.
As shown in
Due to a large amount of TEGs being installed,
A power diagram of the TEG is shown in
In embodiments of a thermoelectric power generation system, the system further may include a solar energy recovery sub-assembly 530 positioned to collect and generate power responsive to solar exposure, and the set of TEG assemblies may be positioned to operate in conjunction with the solar energy recovery sub-assembly to enhance production and distribution of electrical power. The solar energy recovery sub-assembly 530 can be placed at any location where it is possible to capture energy from the sun and can have any configuration (e.g., tiltable) that can assist in capturing solar energy. Also, embodiments may include an onboard electrical supervisory control and data acquisition (SCADA) sub-assembly 540, and the set of TEG assemblies may be positioned to operationally supply power the onboard electrical SCADA sub-assembly to enhance monitoring and operations of other components and circuitry associated with the power generation assembly.
In addition, the set of batteries 520 of the system may be one or more sets of batteries. In embodiments, a fracturing pump auxiliary sub-assembly may be included that may have one or more lube pumps, one or more heat exchangers, one or more pump instruments, and additional sets batteries (or other power sources) and be positioned adjacent the hydraulic fracturing trailer assembly. Accordingly, in such embodiments, as will be understood by those skilled in the art, the set of TEG assemblies may operate to charge a second or additional sets of batteries, thereby to supply power to the fracturing pump auxiliary sub-assembly. Also, some embodiments may include a turbine engine auxiliary sub-assembly having one or more of a fuel sub-assembly, a gearbox sub-assembly, and an air supply sub-assembly, and the set of TEG assemblies may operate to charge the second or additional sets of batteries to supply power to the turbine engine auxiliary sub-assembly.
In a conventional fracturing set up, including a reciprocating diesel engine acting as the prime mover, the power generation is usually provided from an alternator that is directly mounted from a power take-off (PTO) on the engine. In an electrical fracturing set up, the power generation that is supplied from the main turbine genset is conditioned through transformers and switch gear to be able to be used for trailer auxiliaries. The use of an alternator installed on the direct drive turbine engine gearbox which, in turn, is then connected to a reciprocating plunger pump is not a feasible way to generate power. This is primarily a concern with dual shaft turbine engines that may see the Gas Generating Turbine (N1) turn with the Power Shaft (N2) remaining static which in the case of an alternator being installed on the gearbox would result in no power generation. In conjunction with the issue of the two engine shafts rotating separately, there is the case of the turbine engines output speed being variable which is an inevitable condition through the fracturing process. To combat these two complications, a diesel engine connected to a generator, or in other cases a hydraulic pump, is installed to support the power required by the auxiliary systems. These power assemblies are costly, require a lot of maintenance, and take up a lot of space onboard the factoring trailer. The installation of TEG assemblies on the direct drive turbine pump trailer would allow for the reduction in size of the auxiliary engine or, in some cases, the removal of the auxiliary engine from the trailer. The impact of these reductions and removals would not only allow for free space to be increased but also may allow for a reduction in weight allowing for the trailer to be comfortably compliant with state DOT weight and dimension trailer regulations, for example.
An embodiment of a method to generate thermoelectric power for a hydraulic fracturing trailer assembly having a high-power hydraulic fracturing generation assembly positioned thereon, for example, may include operating a high-power turbine engine of the power generation assembly when adjacent a fracturing well site so as to produce exhaust gas therefrom, supplying the exhaust gas from the high-power turbine engine into a turbine engine exhaust stack assembly, and generating thermoelectric power from a set of thermoelectric generation (TEG) assemblies responsive to heat from the exhaust gas in the turbine engine exhaust stack assembly so as to supply power to a power storage and distribution source associated with the hydraulic fracturing trailer assembly. The method also may include operating a diesel engine alternator when connected to the set of TEG assemblies to enhance production and distribution of electrical power across the high-power hydraulic fracturing generation assembly. In embodiments of the disclosure, the turbine engine exhaust stack assembly may include an exhaust stack housing and a TEG housing mount assembly, and the set of TEG assemblies may be mounted to the exhaust stack housing via the TEG housing mount assembly so that the TEG assemblies receive heat from the turbine engine exhaust stack assembly when mounted to the exhaust stack housing. The method further may include controlling power levels associated with components of the high-power hydraulic fracturing generation assembly via a controller and the set of TEG assemblies.
Using TEGs for thermal energy recovery can improve the reliability of the sub-assemblies. These devices, for example, may be solid state, have no moving parts to break or wear, and may operate effectively without failures or otherwise last a long time under sever operating conditions. The TEG assemblies also produce no noise pollution, unlike other methods for power generation, as well as generate no greenhouse gases. As demonstrated in
This U.S. Non-Provisional patent application claims priority to and the benefit of, under 35 U.S.C. § 119(e), U.S. Provisional Application No. 62/705,358, filed Jun. 23, 2020, entitled “Energy Recovery for High Power Pumping Systems and Methods Using Exhaust Gas Heat to Generate Thermoelectric Power,” the disclosure of which is incorporated herein by reference in its entirety.
Having now described some illustrative embodiments of the disclosure, it should be apparent to those skilled in the art that the foregoing is merely illustrative and not limiting, having been presented by way of example only. Numerous modifications and other embodiments are within the scope of one of ordinary skill in the art and are contemplated as falling within the scope of the present disclosure. In particular, although many of the examples presented herein involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. Those skilled in the art should appreciate that the parameters and configurations described herein are exemplary and that actual parameters and/or configurations will depend on the specific application in which the systems, methods, and or aspects or techniques of the disclosure are used. Those skilled in the art should also recognize or be able to ascertain, using no more than routine experimentation, equivalents to the specific embodiments of the disclosure. It is, therefore, to be understood that the embodiments described herein are presented by way of example only and that, within the scope of any appended claims and equivalents thereto, the disclosure may be practiced other than as specifically described. Furthermore, the scope of the present disclosure shall be construed to cover various modifications, combinations, additions, alterations, etc., above and to the above-described embodiments, which shall be considered to be within the scope of this disclosure. Accordingly, various features and characteristics as discussed herein may be selectively interchanged and applied to other illustrated and non-illustrated embodiment, and numerous variations, modifications, and additions further may be made thereto without departing from the spirit and scope of the present disclosure as set forth in the appended claims.
This U.S. Non-Provisional patent application claims priority to and the benefit of, under 35 U.S.C. § 119(e), U.S. Provisional Application No. 62/705,358, filed Jun. 23, 2020, entitled “Energy Recovery for High Power Pumping Systems and Methods Using Exhaust Gas Heat to Generate Thermoelectric Power,” the disclosure of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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62705358 | Jun 2020 | US |