An exhaust energy recovery system (EERS) and associated methods for an engine are disclosed. An embodiment of an EERS, for example, includes an inlet duct that is configured to divert exhaust gas from an exhaust duct of the engine into the recovery system and an outlet duct configured to return the exhaust gas to the exhaust duct downstream of the inlet duct. The recovery system is configured to heat components or fluids associated with engine to operating temperatures. The recovery system may be part of a mobile power system that is mounted to a single trailer and includes an engine and a power unit such as a high pressure pump or generator mounted to the trailer. Methods of operating and purging recovery systems are also disclosed.

An exhaust energy recovery system (EERS) and associated methods for an engine are disclosed. An embodiment of an EERS, for example, includes an inlet duct that is configured to divert exhaust gas from an exhaust duct of the engine into the recovery system and an outlet duct configured to return the exhaust gas to the exhaust duct downstream of the inlet duct. The recovery system is configured to heat components or fluids associated with engine to operating temperatures. The recovery system may be part of a mobile power system that is mounted to a single trailer and includes an engine and a power unit such as a high pressure pump or generator mounted to the trailer. Methods of operating and purging recovery systems are also disclosed.

Methods and systems for supply of fuel for a turbine-driven fracturing pump system used in hydraulic fracturing may be configured to identify when the supply pressure of primary fuel to a plurality of gas turbine engines of a plurality of hydraulic fracturing units falls below a set point, identify a gas turbine engine of the fleet of hydraulic fracturing units operating on primary fuel with highest amount of secondary fuel available, and to selectively transfer the gas turbine engine operating on primary fuel with the highest amount of secondary fuel from primary fuel operation to secondary fuel operation. Some methods and systems may be configured to transfer all gas turbine engines to secondary fuel operation and individually and/or sequentially restore operation to primary fuel operation and/or to manage primary fuel operation and/or secondary fuel operation for portions of the plurality of gas turbine engines.

Methods and systems for supply of fuel for a turbine-driven fracturing pump system used in hydraulic fracturing may be configured to identify when the supply pressure of primary fuel to a plurality of gas turbine engines of a plurality of hydraulic fracturing units falls below a set point, identify a gas turbine engine of the fleet of hydraulic fracturing units operating on primary fuel with highest amount of secondary fuel available, and to selectively transfer the gas turbine engine operating on primary fuel with the highest amount of secondary fuel from primary fuel operation to secondary fuel operation. Some methods and systems may be configured to transfer all gas turbine engines to secondary fuel operation and individually and/or sequentially restore operation to primary fuel operation and/or to manage primary fuel operation and/or secondary fuel operation for portions of the plurality of gas turbine engines.

Embodiments of drive equipment for mobile hydraulic fracturing power units and methods for changing and controlling the drive equipment are disclosed. The mobile power units include a gas turbine engine that provides mechanical power to drive shaft which is connected to the drive equipment such that the drive equipment is driven by the engine. The drive equipment may be a hydraulic fracturing pump or an electrical generator. The drive shaft is rotated at a speed suitable for the hydraulic fracturing pump and the electrical generator includes a step up gearbox to increase a rotational speed of the drive shaft for use by the electrical generator. The drive equipment may be secured to a skid that is field changeable with a crane or a fork lift to change the drive equipment at a well pad based on the demands of the well pad.

A system includes a gas turbine engine having a low speed spool, a high speed spool, and a combustor. The system also includes a low spool motor configured to augment rotational power of the low speed spool. The system further includes a controller configured to cause fuel flow. The controller is operable to control the low spool motor to drive rotation of the low speed spool responsive to a thrust command while the controller does not command fuel flow to the combustor.

The present invention discloses a hydraulic fracturing system for driving a plunger pump with a turbine engine, including a fracturing equipment comprising a turbine engine fueled by natural gas or diesel as a power source, an exhaust system, and a plunger pump; a high-low pressure manifold; a blending equipment adapted to blend a fracturing base fluid; and a sand-mixing equipment adapted to provide the fracturing base fluid and a fracturing proppant to the high-low pressure manifold. A first end of the high-low pressure manifold is connected to the fracturing equipment through a connection pipeline. A second end of the high-low pressure manifold is connected to a wellhead. An exhaust end of the turbine engine is connected to the exhaust system whereas an output driving end of the turbine engine is connected to the plunger pump via a connection device. The connection device comprises at least a reduction gearbox. An input speed of the reduction gearbox matches an output driving speed of the turbine engine, and an input torque of the reduction gearbox matches an output driving torque of the turbine engine. The exhaust system may include a diffuser.

A hybrid powerplant is provided for an aircraft. This aircraft hybrid powerplant includes a housing, an electric machine, a heat engine and a geartrain. The housing includes a containment zone located within the housing. The electric machine is arranged within the containment zone. The heat engine is arranged partially or completely within the housing and outside of the containment zone. The geartrain is arranged partially or completely within the housing and partially or completely outside of the containment zone. The electric machine, the heat engine and the geartrain are operatively interconnected.

A hybrid powerplant is provided for an aircraft. This aircraft hybrid powerplant includes a housing, an electric machine, a heat engine and a geartrain. The housing includes a containment zone located within the housing. The electric machine is arranged within the containment zone. The heat engine is arranged partially or completely within the housing and outside of the containment zone. The geartrain is arranged partially or completely within the housing and partially or completely outside of the containment zone. The electric machine, the heat engine and the geartrain are operatively interconnected.

A hybrid powerplant can include a fuel cell cycle system configured to generate a first power using a fuel and an oxidizer. The powerplant can also include a supercritical carbon dioxide (sCO.sub.2) cycle system operatively connected to the fuel cell cycle to receive heat from the fuel cell cycle to cause the sCO.sub.2 cycle system to generate a second power.