Provided herein is a power generation system and method for transforming thermal energy, such as waste heat, into mechanical energy and/or electrical energy. The system employs features designed to accelerate start times, reduce size, lower cost, and be more environmentally friendly. The system may include multiple compressors on separate pinion shafts with multiple expanders, a temperature valve upstream of compressors with a mass management system downstream, an intercooler between compressors, and a cascade exchanger. In one embodiment, the system is configured to drive a synchronous generator, with the separate pinion shafts rotating at two separate, but constant, speeds.

Provided is a waste heat recovery power generation system, including: a compressor configured to compress a working fluid; a heat exchanger configured to recover waste heat from waste heat gas supplied from a waste heat source, the recovered waste heat heating the working fluid; a turbine configured to be driven by the working fluid heated by the recovered waste heat; and a recuperator configured to exchange heat between an output fluid of the turbine and an output fluid of the compressor to cool the output fluid of the turbine in which the output fluid of the compressor is branched into a first output fluid and a second output fluid of the compressor.

Extra heat in a closed cycle power generation system, such as a reversible closed Brayton cycle system, may be dissipated between discharge and charge cycles. An extra cooling heat exchanger may be added on the discharge cycle and disposed between a cold side heat exchanger and a compressor inlet. Additionally or alternatively, a cold thermal storage medium passing through the cold side heat exchanger may be allowed to heat up to a higher temperature during the discharge cycle than is needed on input to the charge cycle and the excess heat then dissipated to the atmosphere.

Systems and methods relating to use of external air for inventory control of a closed thermodynamic cycle system or energy storage system, such as a reversible Brayton cycle system, are disclosed. A method may involve, in a closed cycle system operating in a power generation mode, circulating a working fluid may through a closed cycle fluid path. The closed cycle fluid path may include a high pressure leg and a low pressure leg. The method may further involve in response to a demand for increased power generation, compressing and dehumidifying environmental air. And the method may involve injecting the compressed and dehumidified environmental air into the low pressure leg.

In some embodiments the disclosure is directed to a closed-loop piston engine system using a recirculating carbon dioxide (CO.sub.2) system with supercritical carbon dioxide (scCO.sub.2) as a working fluid. The closed-loop piston engine system may include a scCO.sub.2 injector; a superheating nozzle region; a first valve; a second valve; a piston moving in the cylinder and coupled with a crankshaft, the piston being driven toward a centerline of the crankshaft during a power stroke using a connecting rod and causing the crankshaft to rotate thereby causing one power stroke per piston per crankshaft rotation and thereby producing two power strokes for every single power stroke that a similar engine would produce if run as a hydrocarbon fuel powered internal combustion engine. The recirculating CO.sub.2 system recirculates the used carbon dioxide and there are no carbon dioxide emissions from the system.

A heat exchanger has arcuate inlet and outlet manifolds and a plurality of tube banks, each tube bank coupling one of the inlet manifold outlets to an associated one of the outlet manifold inlets. Each tube bank partially nests with one or more others of the tube banks and has: a first header coupled to the associated inlet manifold outlet and the associated the outlet manifold inlet; a second header; and a plurality of tube bundles each having a first end coupled to the associated first header and a second end coupled to the associated second header. A flowpath from the each inlet manifold outlet passes sequentially through flowpath legs formed by each of the tube bundles in the associated tube bank to exit the tube bank to the associated outlet manifold inlet.

The present disclosure relates to cogeneration of power and one or more chemical entities through operation of a power production cycle and treatment of a stream comprising carbon monoxide and hydrogen. A cogeneration process can include carrying out a power production cycle, providing a heated stream comprising carbon monoxide and hydrogen, cooling the heated stream comprising carbon monoxide and hydrogen against at least one stream in the power production cycle so as to provide heating to the power production cycle, and carrying out at least one purification step so as to provide a purified stream comprising predominately hydrogen. A system for cogeneration of power and one or more chemical products can include a power production unit, a syngas production unit, one or more heat exchange elements configured for exchanging heat from a syngas stream from the syngas production unit to a stream from the power production unit, and at least one purifier element configured to separate the syngas stream into a first stream comprising predominately hydrogen and a second stream.

The present disclosure relates to the technical field of coal chemical industry, and particularly discloses an integrated coal gasification combined power generation process with zero carbon emission, the process comprising: pressurizing air for performing air separation to obtain liquid oxygen and liquid nitrogen, wherein the liquid oxygen is used for gasification and power generation, the liquid nitrogen is applied as the coolant for the gasification and power generation, the liquid nitrogen and a part of liquid oxygen stored during the valley period with low electricity load are provided for use during the peak period with high electricity load; the pulverized coal delivered under pressure and high-pressure oxygen enter a coal gasification furnace for gasification, so as to generate high-temperature fuel gas, which subjects to heat exchange and purification, and then the high-pressure fuel gas enters into a combustion gas turbine along with oxygen and recyclable CO.sub.2 for burning and driving an air compressor and a generator to rotate at a high speed; the air compressor compresses the air to a pressure of 0.40.8 MPa, and the generator generates electricity; the high-temperature combustion flue gas performs the supercritical CO.sub.2 power generation, its coolant is liquid oxygen or liquid nitrogen; the heat exchanged combustion fuel gas subsequently perform heat exchange with liquid nitrogen, the liquid nitrogen vaporizes to drive a nitrogen turbine generator for generating electricity, the cooled flue gas is dehydrated and distilled to separate CO.sub.2, a part of CO.sub.2 is used for circulation and temperature control, and another portion of CO.sub.2 is sold outward as liquid CO.sub.2 product. The power generation process provided by the present disclosure not only solves the difficult problems of high water consumption, low power generation efficiency and small range of peak load adjustment capacity of the existing IGCC technology; but also can compress air with high unit volume for energy storage with a high conversion efficiency, and greatly reduce load of the air compressor, thereby perform CO.sub.2 capture and utilization with low-cost, zero NO.sub.x emission and discharging fuel gas at a normal temperature, and significantly improve the power generation efficiency.

A method of driving a turbine, the method comprising: (a) providing solid carbon dioxide; (b) heating the solid carbon dioxide to produce a high pressure carbon dioxide fluid; (c) passing the carbon dioxide over a blade of the turbine; and (d) collecting the carbon dioxide that has passed over the turbine blade; wherein carbon dioxide collected in step (d) is in solid form.

A plant for storing energy comprises a casing for the storage of a working fluid other than atmospheric air, in gaseous phase and in equilibrium of pressure with the atmosphere; a tank for the storage of said working fluid in liquid or supercritical phase with a temperature close to the critical temperature. The plant is configured to perform a closed cyclic thermodynamic transformation, first in one direction in a charge configuration and then in an opposite direction in a discharge configuration, between said casing and said tank. In the charge configuration the plant stores heat and pressure and in the discharge configuration the plant generates energy. The plant is also configured to define a closed circuit and to perform a closed thermodynamic cycle in the closed circuit with at least a part of the working fluid.