Patent Grant
12037996
The present invention relates generally to gas compressors, and more particularly to gas compressors that are capable of near isothermal operation.
Currently, gas compression is dominated by electrically driven motors and is a very energy-intensive process. The several energy conversion processes required from power plant to the compressor (fuel→shaft power→electricity→transmission/distribution→shaft power→compression) result in energy losses at each step, which compound into large losses and high primary-energy-use intensity. Furthermore, state-of-the-art compressors used in vapor compression cycles essentially undergo adiabatic compression, which is an energy-inefficient compression trajectory.
There is shown in U.S. Pat. No. 10,519,923 a near isothermal combined compressed gas pumped hydroelectricity storage. A pump directs a working liquid to pressurize a gas that is confined within a pressurized gas vessel. The pump can be powered by electricity provided by a renewable resource such as solar or wind, or by the grid during off-peak periods. The disclosure of this patent is hereby incorporated fully by reference.
A gas compressor system, comprising a a compression liquid holding tank, a combustion tank, and a compression tank. The combustion tank can have a compression liquid inlet in fluid communication with the compression liquid holding tank, a combustible fluid inlet for fluid communication with a combustible fluid source, an ignition system for igniting the combustible fluid, and a compression liquid flow opening. A compression liquid and a compressible gas are provided. A pump is provided for pumping the compression liquid from the compression liquid holding tank to the combustion tank.
The compression tank can have a compression liquid flow opening. The compression liquid flow opening of the compression tank can be in liquid communication with the compression liquid flow opening of the combustion tank.
A valve for controlling flow of the compression liquid between the compression liquid holding tank and the combustion tank can be provided. A valve for controlling fluid communication between the combustion tank and the compression tank can be provided. A valve for controlling the flow of combustible fluid with the combustion tank can also be provided.
The combustible fluid is flowed into the combustion tank and compressible gas is provided in the compression tank. The compression liquid is pumped by the pump from the compression liquid holding tank to the combustion tank, compressing the combustible fluid. The combustible fluid is ignited by the ignition system causing the compression liquid to flow from the combustion tank to the compression tank, compressing the compressible gas in the compression tank. The compressing of the compressible gas can be isothermal.
The compression tank can include at least one selected from the group consisting of a compressible gas inlet and a compressible gas outlet. The compression tank can include a valve for controlling the flow of the compressible gas. The compression tank can have a spray head for introducing compression liquid into the compression tank as a spray.
The combustible fluid can beany suitable combustible fluid. The combustible fluid can be at least one selected from the group consisting of natural gas, gasoline, and diesel fuel. The ignition system can be a suitable ignition system for the combustible fluid that is being used. For example, the ignition system can include a spark generator.
A hydraulic pressure intensifier can be provided. The hydraulic pressure intensifier can increase the pressure of the compression liquid flowing from the combustion tank to the compression tank.
The compressible gas can be selected from many possible compressible gases. The compressible gas can be, for example, at least one selected from the group consisting of air, hydrogen, CO2, natural gas, hydrocarbon gases, and refrigerant gases.
A refrigeration or heat pump system according to the invention can include a gas compressor system according to the invention, and a condenser or gas cooler, an expansion device, and an evaporator. The compressible gas can be a suitable refrigerant.
A method for compressing a gas can include the steps of providing a compression liquid holding tank, a combustion tank and a compression tank. The combustion tank can have a compression liquid inlet in fluid communication with the compression liquid holding tank, a combustion gas inlet for communicating with a combustion gas source, and a compression liquid outlet. The compression tank can have a compression liquid flow opening. The compression liquid flow opening of the compression tank can be in liquid communication with the compression liquid flow opening of the combustion tank.
A compression liquid is provided in the compression liquid holding tank. A compressible gas is provided in the compression tank/. A combustible fluid is flowed into the combustion tank. The compression liquid is pumped from the compression liquid holding tank to the combustion tank, compressing the combustion gas;
The combustible fluid is combusted, causing the compression liquid to flow from the combustion tank to the compression tank, compressing the compressible gas in the compression tank. The compressed compressible gas upon changing of the valve causes the compression liquid to flow to the combustion tank to displace and remove combustion gases from the combustion tank. The compression of the compressible gas can be isothermal.
A gas compressor includes a compression liquid holding tank, a combustion tank and a compression tank. The combustion tank can have a compression liquid inlet in fluid communication with the compression liquid holding tank, a combustible fluid inlet for fluid communication with a combustible fluid source, an ignition system for igniting the combustible fluid, and a compression liquid flow opening. A compression liquid can be provided. A pump is provided for pumping the compression liquid from the compression liquid holding tank to the combustion tank. The compression tank can have a compression liquid flow opening, the compression liquid flow opening of the compression tank being in liquid communication with the compression liquid flow opening of the combustion tank. A valve can be provided for controlling fluid communication between the combustion tank and the compression tank. A valve can be provided for controlling the flow of combustible fluid with the combustion tank. The combustible fluid is flowed into the combustion tank and compressible gas is provided in the compression tank, the compression liquid is pumped by the pump from the compression liquid holding tank to the combustion tank, compressing the combustible fluid, and the combustible fluid is ignited by the ignition system causing the compression liquid to flow from the combustion tank to the compression tank, compressing the compressible gas in the compression tank. The gas compressor can further include a hydraulic pressure intensifier to increase the pressure of the compression liquid from the combustion tank to the compression tank.
There are shown in the drawings embodiments that are presently preferred it being understood that the invention is not limited to the arrangements and instrumentalities shown, wherein:
A gas compressor system according to the invention includes a compression liquid holding tank, a combustion tank and a compression tank. The relative dimensions, design, and materials of these tanks can vary according to the design parameters of intended use of the gas compressor system.
The combustion tank includes a compression liquid inlet in fluid communication with the compression liquid holding tank. A combustible fluid inlet is provided for fluid communication between the combustion tank and a combustible fluid source.
Compression liquid flow openings with suitable connected conduits allows the flow of a compression liquid into and from the compression liquid holding tank, the combustion tank, and the compression tank. The compression liquid flows between the combustion tank and the liquid holding tank, and between the combustion tank and the compression tank. A pump can be provided for pumping the compression liquid from the compression liquid holding tank to the combustion tank.
The compression tank has a compression liquid flow opening to permit the inflow and/or outflow of compression liquid. A separate compression liquid inlet and compression liquid outlet are possible. The compression liquid flow opening of the compression tank is in liquid communication with the compression liquid flow opening of the combustion tank.
Valves can control the flow of the compression liquid between the combustion tank and compression liquid holding tank and the combustion tank. Valves controls the flow of compression liquid between the combustion tank and the compression tank. Valves can control the flow of combustible fluid and combustion products to and from the combustion tank. Valves can control the flow of compressible gas into and from the compression tank. The design of these valves can vary. The valves can be the same design or different designs.
Many different compression liquids are possible. Examples include water, oils, and hydraulic fluids. Other compression liquids are possible. The compression liquid should be substantially unreactive with the combustible fluid or combustion reaction products, and with the gas being compressed. The compression liquid should also be substantially stable at the desired operating conditions such as temperature and pressure of the gas compressor. The compression liquid should also be immiscible with the compressible gas.
A combustible fluid is provided. Many different combustible fluids are possible. The combustible fluid can include natural gas. Oxygen from a suitable gas source such as air can be added. The combustible fluid can comprise a liquid fuel sprayed and combined with oxygen prior to ignition, for example, gasoline or diesel fuel and oxygen gas.
A compressible gas is provided. The compressible gas constitutes the working fluid of the gas compressor system, and accordingly different compressible gases can be used for different purposes. The compressible gas in one embodiment can be a refrigerant for the refrigeration cycle of a heating, ventilation, air conditioning and refrigeration HVAC&R system. Many such synthetic and natural refrigerants are known, such as R32, R410A, R515B, R717 (ammonia), R290, and R744 (CO2). Other compressible gases can be used, for example in energy storage applications. Examples of such gases are air, hydrogen, CO2, ammonia and hydrocarbon gases. The invention can be used to compress natural gas to make compressed natural gas (CNG) and liquid natural gas (LNG).
In operation, the combustible fluid is flowed into the combustion tank and the compressible gas is provided in the compression tank. The compression liquid is pumped by the pump from the compression liquid holding tank to the combustion tank, compressing the combustible fluid. The combustible fluid is ignited by the ignition system causing the compression liquid to flow from the combustion tank to the compression tank, compressing the compressible gas in the compression tank.
The compression tank can include a spray head for introducing compression liquid into the compression tank as a spray. The spray assists in keeping the process near isothermal. The term isothermal as used herein means an isothermal compression efficiency of at least 95, 95.5, 96, 96.5, 97, 97.5, 98, 98.5, 99, 99.5 or 100%, or within a range of any high value and low value selected from these values. The droplets sizes of the spray can vary. The spray droplets remove some or most of the heat of compression from the compressible gas. The removal of some or most of the compression heat brings the pressure-volume trajectory of the compression process closer to the isothermal trajectory.
The gas compressor system can include a hydraulic pressure intensifier to increase the pressure of the compression liquid flowing from the combustion tank to the compression tank. Hydraulic pressure intensifiers take in a fluid at one pressure, and discharge the liquid at another, usually higher, pressure.
An ignition system is provided for igniting the combustible fluid. The ignition system can include a spark generator. Other ignition systems for igniting combustible fluids are possible, for example diesel-like ignition.
The design and sizing of the pumps that are used in the invention can vary. Pumps in some instance can be omitted where for example suitable head is available to drive the movement of the liquid is a desired fashion.
A refrigeration system includes a gas compressor system, a condenser or gas cooler, an expansion device, and an evaporator. The gas compressor system includes a compression liquid holding tank, a combustion tank, and a compression tank. The combustion tank includes a compression liquid inlet in fluid communication with the compression liquid holding tank, a combustible fluid inlet for fluid communication with a combustible fluid source, an ignition system for igniting the combustible fluid, and a compression liquid flow opening. A pump is provided for pumping the compression liquid from the compression liquid holding tank to the combustion tank. The compression tank has a compression liquid flow opening. The compression liquid flow opening of the compression tank is in liquid communication with the compression liquid flow opening of the combustion tank. A valve can be provided for controlling fluid communication between the combustion tank and the compression tank. A valve can be provided for controlling the flow of combustible fluid with the combustion tank. A combustible fluid is flowed into the combustion tank and a compressible gas is provided in the compression tank. The compression liquid is pumped by the pump from the compression liquid holding tank to the combustion tank, compressing the combustible fluid. The combustible fluid is ignited by the ignition system causing the compression liquid to flow from the combustion tank to the compression tank, compressing the compressible refrigerant gas in the compression tank. This compressed refrigerant gas can then be used as part of an HVAC&R system.
The HVAC&R system can be any suitable such system which requires compression of a refrigerant. Such systems typically include a condenser or gas cooler, an expansion device, and an evaporator. The invention can be used with a heat pump system.
A method for compressing a gas includes the steps of providing a compression liquid holding tank, and providing a combustion tank. The combustion tank includes a compression liquid inlet in fluid communication with the compression liquid holding tank, a combustion gas inlet for communicating with a combustion gas source, and a compression liquid outlet. A compression liquid is provided in the compression liquid holding tank. A compression tank is provided, and can include a compression liquid flow opening. The compression liquid flow opening of the compression tank being in liquid communication with the compression liquid flow opening of the combustion tank.
A compressible gas is provided in the compression tank. The combustible fluid is flowed into the combustion tank. The compression liquid is pumped from the compression liquid holding tank to the combustion tank, compressing the combustion gas. The combustible fluid is combusted causing the compression liquid to flow from the combustion tank to the compression tank, compressing the compressible gas in the compression tank. The compressed compressible gas upon changing of the valve causes the compression liquid to flow to the combustion tank to displace and remove combustion gases from the combustion tank. The compression of the compressible gas can be isothermal or near isothermal. The method can include the step of utilizing a hydraulic pressure intensifier to increase the pressure of the compression liquid from the combustion tank to the compression tank.
There is shown in
A combustible fluid can enter the combustion tank 18 through a suitable combusted gas inlet conduit 50. A valve 52 can be used to control the flow of combustible fluid 54 into the combustion tank 18 as shown by arrows 56 as the level of compression liquid 38 falls as shown by arrow 58. Gas combustion products can exit the combustion tank 18 through a suitable exhaust conduit 62 which can be controlled by a valve 66.
The compression liquid 38 can exit the combustion tank 18 through a compression liquid exit conduit 70 which communicates with compression liquid flow openings in the combustion tank 18 and the compression tank 22. Compression liquid 38 can flow from the conduit 70 and a spray head supply conduit 74 and control valve 76 to spray head 78. The compression liquid 38 can alternatively flow through a branch 80 and control valve 84 into the compression tank 22. An ignition system such as spark generator 124 is provided in the combustion tank 18.
A compressible gas 88 enters the compression tank 22 through a suitable conduit 92. Flow of the compressible gas 88 into the compression tank 22 is controlled through a suitable valve 96 and in the open condition the valve 96 permits flow of compressible gas into the compression tank 22 is indicated by arrows 100. The flow of compressible gas 88 out of the compression tank 22 can be through a conduit 104 and can be controlled by a valve 108.
The flow of compression liquid out of the compression tank 22 is through a suitable conduit 112 which communicates with compression liquid flow openings in the combustion tank 18 and the compression tank 22. The flow of compression liquid out of the compression tank 22 can be assisted by pump 116 and controlled by control valve 120.
A suitable processor 130 can be provided to control operation of the gas compressor assembly 10. The processor 130 can communicate with the valves, pumps and other process equipment such as temperature and pressure sensors. This communication can be through suitable wired or wireless connections.
As shown in
As shown in
The ignition system is then operated to combust the combustible fluid 54, as shown in
System is charged and the compressible gas is in a compressed condition and can be stored in that condition until use of the compressed gas is desired. As shown in
The gas compressor system 10 is cycled back to the original condition beginning with removal of the compression liquid 38 from the compression tank 22 to the combustion tank 18, as shown by arrows 170 in
The valve 66 is closed when the combusted the gases 162 have exited the combustion tank 18, as shown in
The pressure of the compression liquid 38 entering the compression tank 22 can be increased by the operation of a suitable pump. Alternatively, a pressure increasing device 182 such as a hydraulic pressure intensifier 186 can be utilized, as shown in
The gas compressor system of the invention can be used as part of an HVAC&R system. There is shown in
The invention has many possible applications across a wide range of energy systems and devices, including vapor-compression heating/cooling, industrial compressed gas distribution, CO2 compression/storage, hydrogen compression/storage, and others. The invention enables a step reduction in gas/refrigerant compression primary energy consumption through site utilization of NG, reducing the number of energy conversion steps by half and achieving (near) isothermal compression. Additional benefits include decoupling of heating, ventilation, air-conditioning and refrigeration (HVAC&R) and cooling system loads from the grid and simpler geometric compressor designs. The invention also can provide adjustable compression ratio capabilities that make one compressor compatible with all refrigerants and applications and maintains high compression efficiency during part-load operation. The system can be modular, and parallel or series combinations of the gas compressor system of the invention can be utilized to provide a more continuous source of the compressed compressible gas. In series, the invention can act as a multistage compressor for extremely high-pressure applications such as hydrogen gas compression.
Sprayed droplets with broad range of diameter sizes of 10 to 2500 micrometers can be employed. More specifically, the droplet size that is most beneficial to this technology range is 300 to 900 micrometers and the most optimal range is 400 to 700 micrometers. The droplet size can be 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, 550, 575, 600, 625, 650, 675, 700, 725, 750, 775, 800, 825, 850, 875, and 900 micrometers, or within a range of any high value and low value selected from these values. In HVAC&R applications, scroll-type compressors are typically the compressors of choice and are limited to maximum efficiencies of around 65%. In hydrogen compression, compressor efficiencies are stated to currently be around 65-70%, with a goal of reaching 80%. The invention combines the gas compressor technology which enables site utilization of NG to drive compression, thereby improving efficiency by reducing the number of energy conversion steps needed and bringing the primary energy source to the end use, and utilizes liquid piston compression combined with advanced heat exchange via micron-sized sprayed droplets to achieve near isothermal compression, which is an energy-efficient, thermodynamically ideal compression trajectory.
Compared with adiabatic compression—the state-of-the-art compression trajectory for existing compressor technologies—isothermal compression has the potential to save 10-24% of specific energy consumption. This is shown in
Table 1 presents a comparison between the proposed compressor and the state of the art. Note that the primary fuel to compression efficiency in the state of the art electric scroll compressors is approximately η˜17-26% (i.e., natural gas→shaft power in power plants (η1˜55%)→electricity (η2˜97%)→electricity transmission/distribution (η3˜85%)→motor (η4˜55-90%)→scroll compressor (η5˜65%)). By eliminating the above conversion losses and introducing a direct conversion of natural gas combustion pressure to refrigerant (or gas) compression, the primary fuel to compression efficiency of the proposed technology is calculated to be 55%.
The invention could provide annual energy savings of up to 10,000 TBTU primary energy with at-scale deployment across most/all compressor applications. Compressed air systems account for 10% of all electricity and 16% of all motor system energy use by US manufacturers, or approximately 91,000 GWh/year. The use of the gas compressor system of the invention at scale in industrial compressed air systems could result in savings of 9,105-21,852 GWh (31-75 TBTU) per year. The invention has the potential to decouple several energy systems loads such as HVAC, compressed air, CO2 compression, and hydrogen compression from the electrical grid, which is already overstrained, by burning natural gas locally to drive compression. The gas compressor of the invention is less complex than state-of-the-art compressor designs in an engineering sense, leading to simpler geometries and streamlined, cheaper manufacturing processes. In addition, the gas compressor system of the invention can reduce overall primary energy use by enabling site utilization of abundant natural gas, avoiding significant energy losses incurred through the many energy conversion steps needed to convert primary energy to the electricity required to power state-of-the-art compressors. This can double the primary fuel to compression efficiency and can significantly benefit vapor compression technology.
The invention as shown in the drawings and described in detail herein disclose arrangements of elements of particular construction and configuration for illustrating preferred embodiments of structure and method of operation of the present invention. It is to be understood however, that elements of different construction and configuration and other arrangements thereof, other than those illustrated and described may be employed in accordance with the spirit of the invention, and such changes, alternations and modifications as would occur to those skilled in the art are considered to be within the scope of this invention as broadly defined in the appended claims. In addition, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
This application claims priority to U.S. Provisional Patent Application No. 63/084,742 filed on Sep. 29, 2020, entitled “FUEL DRIVEN NEAR ISOTHERMAL COMPRESSOR”, the entire disclosure of which incorporated herein by reference.
This invention was made with government support under Contract No. DE-AC05-00OR22725 awarded by the U.S. Department of Energy. The government has certain rights in this invention.
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| Number | Date | Country | |
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| 63084742 | Sep 2020 | US |
