HYDROGEN COOLING

Abstract

Hydrogen liquification includes three streams of refrigerant at between 320 to 425 degrees F. A fourth stream has ambient temperature and pressure between 150 to 650 PSIA. Fourth stream cooling flows are cooled by heat exchangers to between 320 to 270 degrees F. A first flow of these cooling flows is reduced across a valve to a two-phase mixture directed to fourth warming flows. A separate fifth stream has ambient temperature and pressure of between 700 and 1200 PSIA. Fifth stream cooling flows have a first flow portion removed by a splitter at between 0 and 60 degrees F., and a second flow portion removed at between 160 and 100 degrees F. The first flow portion and a cooled flow of the second flow portion are feed into expanders that power fifth compressors to reduce a temperature of the fifth stream to serve as the first and second flow portions.

Claims

1. A hydrogen gas liquification system comprising: a first stream, a second stream and a third stream each including flows of one of fluid or gas at a temperature of between in 320 to 425 degrees Fahrenheit (F); a fourth stream not mixed with each of the first stream, the second stream and the third stream; the fourth stream having a first refrigerant having an ambient temperature of between 60 to 150 degrees F. and a pressure of between 150 to 650 pounds per square inch absolute (PSIA); the fourth stream cooled through fourth cooling flows by one or more heat exchangers to cryogenic temperatures in a range of between 320 to 270 degrees F., wherein a cryogenic liquid first refrigerant flow of the fourth cooling flows is reduced in pressure across a valve such that a temperature of the first refrigerant flow drops due to a Joule-Thomson effect, and a two-phase mixture of the first refrigerant flow is directed to fourth warming flows of the one or more heat exchangers to vaporize the liquid and heat the fluid of the first refrigerant flow to near-ambient conditions of a second refrigerant flow of the fourth warming flows, the second refrigerant flow of the fourth stream is then compressed and cooled through at least one compressor and cooling stage and returned to the fourth cooling flow; a fifth stream not mixed with each of the first stream, the second stream, the third stream or the fourth stream; the fifth stream having a second refrigerant having the ambient temperature of between 60 to 150 degrees F. and a high pressure of between 700 and 1200 PSIA; the fifth stream cooled through fifth cooling flows by the one or more heat exchangers; a first flow portion of the fifth stream removed by a splitter SP2 from a first refrigerant flow of the fifth cooling flows at a first temperature of between 0 and 60 degrees F., and a second remainder flow portion of the fifth stream removed by the splitter from the first refrigerant flow of the fifth cooling flows at a second and relatively colder temperature than the first temperature of between 160 and 100 degrees F.; and the first flow portion and a cooled flow of the second flow portion of the fifth stream each feed into an expander that mechanically powers a fifth compressor to reduce a temperature of the fifth stream to serve as fifth warming flows.

2. The system of claim 1, wherein each expander transfers work energy from fluid of each of the first flow portion and cooled flow into a shaft which powers the fifth compressors.

3. The system of claim 1, further comprising a third flow portion of the fifth stream as a gas or two-phase mixture is brought into the fifth warming flows of the one or more heat exchangers, wherein in the third flow portion of the fifth stream is fully vaporized and warmed and mixed with a fourth flow portion of the fifth stream by a recombiner or mixer such that a mixed stream flow is further warmed by a part of the one or more heat exchangers to the near ambient temperature of between 60 and 150 degrees F.; the mixed stream compressed and cooled through at least one compressor and cooling stage and sent to an input of a fifth compressor.

4. The system of claim 1, wherein during a turndown operation of the system, a mass flow of the fifth stream is reduced by reducing pressure of the second refrigerant by a selected percentage that is based on the percentage or amount of flowrate turndown desired.

5. The system of claim 4, wherein during the turndown operation the system is configured to run at a reduced flowrate at or below 30% of a full load flowrate the system is capable of running at.

6. The system of claim 4, wherein during the turndown operation, pressures of the fifth stream are reduced by releasing coolant, cryogenic fluid or nitrogen of the fifth stream at pressure release valve to lower electrical power needed by a compressor to perform compression of the fifth stream.

7. The system of claim 4, wherein reducing pressures of the second refrigerant includes maintaining a fixed pressure ratio or head change across stages of the fifth stream resulting in a relatively steady volumetric flow and head change through the compression and expansion stages resulting in high efficiency of operation with a reduced electrical load.

8. The system of claim 1, wherein the first refrigerant is nitrogen and the second methane; and wherein none of the liquid, gas or chemical in the fourth stream is combined or mixed with that of the fifth stream.

9. The system of claim 1, wherein the first refrigerant and the second refrigerant are each one of nitrogen, a hydrocarbon, oxygen, hydrogen, helium, or a mixture of these molecules; and wherein each of the first stream, the second stream and the third stream include one of product hydrogen; or refrigerants selected from one of hydrogen, helium, and neon or blends of multiple of those refrigerants.

10. An efficient pre-cooling Modified Reverse-Brayton Cycle hydrogen cooling system comprising: a first chemical stream, a second chemical stream and a third chemical stream each including flows of one of fluid or gas at a temperature of between in 320 to 425 degrees Fahrenheit (F); a fourth chemical stream having flows that are separate from flows of each of the first chemical stream, the second chemical stream and the third chemical stream; the fourth chemical stream cooled through fourth cooling flows by one or more heat exchangers to cryogenic temperatures in a range of between 320 to 270 degrees F. wherein a cryogenic liquid first refrigerant flow of the fourth cooling flows is reduced in pressure across a Joule-Thomson (J-T) valve such that a temperature and pressure of the first refrigerant flow drops due to a Joule-Thomson effect; a two-phase mixture of the first refrigerant flow is directed to fourth warming flows of the one or more heat exchangers to vaporize the liquid and heat the fluid of the first refrigerant flow to near-ambient conditions of a second refrigerant flow of the fourth warming flows, a fifth chemical stream separate from each of the first chemical stream, the second chemical stream, the third chemical stream and the fourth chemical stream; the fifth chemical stream having a refrigerant including nitrogen having the ambient temperature of between 60 to 150 degrees F. and a high pressure of between 700 and 1200 psia; the fifth chemical stream cooled through fifth cooling flows by the one or more heat exchangers; a first flow portion of the fifth chemical stream removed by a splitter from a first refrigerant flow of the fifth cooling flows at a first temperature of between 0 and 60 degrees F.; a second remainder flow portion of the fifth chemical stream removed by the splitter from the first refrigerant flow of the fifth cooling flows at a second and relatively colder temperature than the first temperature of between 160 and 100 degrees F.; the first flow portion of the fifth chemical stream feed into a first expander that mechanically uses a first shaft to power a first compressor of the fifth chemical stream to reduce a temperature of the fifth chemical stream to serve as a first flow portion of the fifth warming flow; and a cooled flow of the second flow portion of the fifth chemical stream feeds into a second expander that mechanically uses a second shaft to power a second compressor of the fifth chemical stream to reduce the temperature of the fifth chemical stream to serve as the second flow portion of the fifth warming flow.

11. The system of claim 10, wherein each of the first and second expanders transfer work energy from fluid of each of the first flow portion and cooled flow portion into the first and second shaft which power the first and second compressors, resulting in a reduced temperature of the fifth chemical stream.

12. The system of claim 10, wherein during a turndown operation of the system, a mass flow of the fifth stream is reduced by reducing pressure of the second refrigerant at a pressure release valve by a selected percentage that is based on the percentage or amount of flowrate turndown desired.

13. The system of claim 12, wherein during turndown operation of the system, the system is configured to run at or below 30% of a full load flowrate the system is capable of running at.

14. The system of claim 10, wherein the first refrigerant is not the same refrigerant as the second refrigerant; and wherein none of the liquid, gas or chemical in the fourth stream is combined or mixed with that of the fifth stream.

15. A method of hydrogen liquification comprising: providing a first stream, a second stream and a third stream each including flows of one of fluid or gas at a temperature of between in 320 to 425 degrees Fahrenheit (F); providing a fourth stream separate from each of the first stream, the second stream and the third stream, the fourth stream having a first refrigerant of primarily nitrogen having an ambient temperature of between 60 to 150 degrees F. and a pressure of between 150 to 650 psia (pounds per square inch absolute); cooling the fourth stream through fourth cooling flows by one or more heat exchangers to cryogenic temperatures in a range of between 320 to 270 degrees F.; reducing pressure of a cryogenic liquid first refrigerant flow of the fourth cooling flows across a Joule-Thomson valve such that a temperature of the first refrigerant flow drops due to a Joule-Thomson effect; directing a two-phase mixture of the first refrigerant flow to fourth warming flows of the one or more heat exchangers to vaporize the liquid and heat the fluid of the first refrigerant flow to near-ambient conditions of a second refrigerant flow of the fourth warming flows; providing a fifth stream not mixed with each of the first stream, the second stream, the third stream and the fourth stream, the fifth stream having a second refrigerant of primarily nitrogen having the ambient temperature of between 60 to 150 degrees F. and a high pressure of between 700 and 1200 psia; cooling the fifth stream through fifth cooling flows by the one or more heat exchangers; removing a first flow portion of the fifth stream by a splitter from a first refrigerant flow of the fifth cooling flows at a first temperature of between 0 and 60 degrees F.; removing a second remainder flow portion of the fifth stream by the splitter from the first refrigerant flow of the fifth cooling flows at a second and relatively colder temperature than the first temperature of between 160 and 100 degrees F.; and feeding each of the first flow portion and a cooled flow of the second flow portion of the fifth stream into expanders that mechanically use a shaft to power fifth compressors to reduce a temperature of the fifth stream to serve as fifth warming flows.

16. The method of claim 15, further comprising compressing and cooling the second refrigerant flow of the fourth stream through at least one compressor and cooling stage and returned to the fourth cooling flow.

17. The method of claim 15, further comprising transferring work energy from fluid of each of the first flow portion and the cooled flow into a shaft which powers the fifth compressors.

18. The method of claim 15, further comprising performing a turndown operation of the system including reducing a mass flow of the fifth stream by reducing pressure of the second refrigerant by a selected percentage that is based on a percentage of a desired turndown flowrate.

19. The method of claim 18, wherein the turndown operation includes reducing a system flowrate to below one of 30%, 70% or 80% of a full load flowrate the system is capable of running at.

20. The method of claim 18, wherein the turndown operation includes reducing a pressures of the fifth stream at a pressure release valve by releasing coolant, cryogenic fluid or nitrogen of the fifth stream to lower electrical power needed by a compressor to perform compression of the fifth stream.

21. The method of claim 15, wherein the first refrigerant is nitrogen and the second refrigerant is methane; and wherein none of the liquid, gas or chemical in the fourth stream is combined or mixed with that of the fifth stream.

Description

DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a ball and stick model of hydrogen gas.

[0013] FIG. 2 is a model of hydrogen gas focusing on electrons protons and interactions between atoms.

[0014] FIG. 3A is a drawing of an efficient hydrogen cooling system.

[0015] FIG. 3B is a drawing of another efficient hydrogen cooling system.

[0016] FIG. 4 is a flow chart of a process for efficient hydrogen cooling.

DETAILED DESCRIPTION

[0017] The technologies (e.g., systems, devices and methods) described herein provide a novel variation of the Modified Reverse-Brayton Cycle for efficient hydrogen cooling such as to liquify hydrogen gas. The technologies described herein may or may not use a Nitrogen Cycle since embodiment include using alternative fluids (e.g., chemicals or refrigerants) in independent or separate streams or flows D and E. The technologies described herein ensure that the high-pressure nitrogen or methane which is brought to the J-T valve of the Modified Reverse-Brayton Cycle to be condensed is instead maintained at a steady pressure throughout operation, avoiding the issues noted above for the Modified Reverse Brayton Cycle. In some cases, that J-T valve is valve V_Cond of stream D between flows D06 and D07. The descriptions herein prevent the mixture of the near-atmospheric nitrogen stream with the turboexpander exhaust nitrogen stream of the Modified Reverse Bayton Cycles, and thus optimize the ability of the new systems and methods to reduce their capacity without losing efficiency. The technologies herein may be or include systems such as system 300 that are pre-cooling system of a system that cools hydrogen gas, produces liquid hydrogen or are for liquification of hydrogen.

[0018] Liquid hydrogen is a versatile and valuable substance that has many important uses in a variety of different industries. The molecular structure of hydrogen gas as shown in FIG. 1 and FIG. 2 contribute to hydrogen's unique properties as a cryogenic liquid. Hydrogen gas, or diatomic hydrogen, is composed of two hydrogen atoms bonded together by a covalent bond. The molecular formula for hydrogen gas is H.sub.2. The molecular structure of hydrogen gas is simple, consisting of just two hydrogen atoms bonded together. One of the key physical properties of hydrogen gas is its low density. Hydrogen gas is the lightest of all gases, with a density of just 0.08988 g/L (sometimes rounded to 0.07 g/mL) at standard temperature and pressure. This low density is due to the small size of the hydrogen atom and the low atomic weight of hydrogen. Another important physical property of hydrogen gas is its flammability. Hydrogen gas is highly flammable and will ignite in the presence of an ignition source. This flammability is due to the chemical reactivity of hydrogen, which is a result of the high energy content of the bonds between the hydrogen atoms in the molecule.

[0019] Hydrogen gas has a very low boiling point, with a boiling point of just 252.87 C. at standard pressure. This low boiling point is due to the weak intermolecular forces between hydrogen molecules, which allows them to easily escape from the liquid phase into the gas phase. The low boiling point also allows hydrogen to be an excellent cryogenic liquid as hydrogen may remain a liquid at low temperatures that would make other chemicals solid. Liquid hydrogen may be used as a fuel for rockets. It is extremely lightweight and has a high energy content, making it an ideal choice for use in space travel. Along with rocket fuel, liquid hydrogen is also used in certain fuel cells. Fuel cells are devices that generate electricity through a chemical reaction, and they have the potential to be a clean and efficient source of energy. Liquid hydrogen is used as a fuel in certain types of fuel cells, particularly those that use proton exchange membrane (PEM) technology.

[0020] Liquid hydrogen is also used in the production of semiconductors. Some semiconductors are produced through a process called deposition, in which thin layers of material are deposited onto a substrate. Liquid hydrogen is used in some deposition processes as a coolant, helping to maintain the low temperatures that are necessary for the production of high-quality semiconductors. One of the most common industrial uses for liquid hydrogen is in the research and development of coolant and refrigerant. LH.sub.2 (liquid hydrogen, the addition of an L to the chemical symbol may indicate the chemical is in liquid form) has a very low boiling point, making it an effective choice for cooling equipment and materials to extremely low temperatures. This is particularly useful in fields such as cryogenics, which involves the study and use of materials at very low temperatures.

[0021] Liquid nitrogen (LN.sub.2) is a colorless, odorless, and tasteless cryogenic liquid that is produced by cooling and compressing atmospheric nitrogen gas. It is commonly used in a variety of applications due to its unique properties and versatility. One of the main uses of liquid nitrogen is as a refrigerant. LN.sub.2's extremely low boiling point of 196 C. makes it an effective choice for refrigeration and cryogenic storage.

[0022] Liquid helium is a cryogenic liquid that is produced by cooling and compressing helium gas. It is the coldest naturally occurring substance on Earth, with a boiling point of 269 C., and it has a number of unique properties and uses. One of the most well-known uses of liquid helium is as a coolant. Liquid helium's extremely low boiling point makes it an effective choice for cooling materials and equipment to very low temperatures. It is commonly used in research and development, particularly in the fields of cryogenics and superconductivity.

[0023] Liquid oxygen is a cryogenic liquid that may be produced by cooling and compressing oxygen gas. It is pale blue and transparent when in liquid form and when pumped in the disclosed system. One of the main uses of liquid oxygen is as a respiratory gas.

[0024] Liquid neon is a cryogenic liquid that is produced by cooling and compressing neon gas. It is a transparent liquid that has a number of unique properties and uses. One of the main uses of liquid neon is as a refrigerant. Liquid neon's extremely low boiling point of 246 C. makes it an effective choice for refrigeration and cryogenic storage.

[0025] Liquid argon is a cryogenic liquid that is produced by cooling and compressing argon gas. When in liquid form argon is colorless, odorless, and tasteless. One use of liquid argon is as a refrigerant. Argon's extremely low boiling point of 186 C. makes it an effective choice for refrigeration and cryogenic storage. It is commonly used to store materials at extremely low temperatures, such as biological samples and industrial chemicals.

[0026] Liquid methane is a cryogenic liquid produced by cooling and compressing methane gas. It is a colorless, odorless, and tasteless liquid that has a number of unique properties and uses. One of the main uses of liquid methane is as a fuel.

[0027] The efficient hydrogen cooling technologies (e.g., systems, devices and methods) described herein allow for stable and efficient turndown of a hydrogen liquefier's precooling section. This efficient operation allows for the economic operation of the hydrogen liquefier as demand for product falls below the nameplate capacity of the plant or when electrical grid's available power drops. The power may be measured as electrical power or watts such as in joules of energy per second and or voltage x current per second.

[0028] Multiple cryogenic liquids may be mixed together and/or used in the efficient hydrogen cooling technologies described herein. The cryogenic liquids may include those named herein, light hydrocarbons, refrigerants, nitrogen, methane, mixtures of those molecules and/or blends of multiple refrigerants.

Description of Apparatus

[0029] Referring now to FIG. 3A, a system 300 for efficient cooling of hydrogen. Such cooling may be or be part of a novel variation of the Modified Reverse-Brayton Cycle for efficient hydrogen cooling such as to liquify hydrogen gas into liquid hydrogen. System 300 may be or include a system that is a pre-cooling system of a system that cools hydrogen gas, produces liquid hydrogen or are for liquification of hydrogen. System 300 has stream A302, stream B304, and stream C306 which each or all represent streams which are used in the 320 to 425 F sections of a hydrogen cooling system which may include product hydrogen and refrigerants, such as hydrogen, helium, or neon, or blends of multiple refrigerants. A hydrogen cooling or liquification system can be considered efficient when the total electrical power consumption is low when normalized by the total amount of external cooling or total liquid production. This can be further analyzed by considering the efficiency not only at the design point but also during turndown when the demand for external cooling or liquid production is decreased. When this turndown occurs, the efficiency will become worse unless the electrical power can also be reduced using some design feature of the system. When this turndown occurs, the efficiency of cooling hydrogen may be more efficient or efficient when the electrical power can also be reduced using some design feature of the system, such as using streams D and E as part of the system as described herein. In some cases, the efficiency may be more efficient or efficient cooling of hydrogen includes the reduction of electrical power needed during turndown, such as by the compressors due to the reduction in pressure of stream E which is not combined with stream D and thus makes the system more efficient. In some cases, the efficiency may be more efficient or efficient cooling of hydrogen includes using expanders and shafts to power the compressors of stream E instead of using electrical power.

[0030] The configuration of stream D310 and stream -312 (or stream D310 and stream E352) are one basis of the technologies described herein wherein the nitrogen which is to be liquefied is kept in its stream D or loop (D) and not mixed with the primary refrigeration, refrigerant or cryogenic liquid of stream E or loop (E). That is, none of the liquid, gas or chemical in stream D is combined or mixed with any of the liquid, gas or chemical in stream E. In some cases, stream D does not touch or interact with stream E other than through heat exchangers HEX_1 through HEX_4. Stream D and E may change the temperature or each other through the heat exchangers HEX_1-4 as shown. Streams D and E may be pre-cooling streams.

[0031] The streams A-E flow through one or more of heat exchangers HEX_1-HEX_6 as shown. Each stream may be a stream of or including liquid, gas, or gas and fluid of a cryogenic or refrigerant matter, chemical and/or molecule. Each stream includes multiple sub-streams or flows such as stream E312 including flows E01, flow E02 . . . through flow E18. Each stream may include one or more stages such as heating, cooling, compressing and/or cooler stages. Each stream and flow moves or flows in the direction indicated by the arrows in the stream and of its flow, such as flow A01 of stream A flowing through heat exchanger HEX_1 to become flow A02, etc. In some cases, the heat exchangers can be combined such as combining HEX_1 and HEX_2 for streams A-D to have the combined heat exchange of those two exchangers. Each heat exchanger may be a brazed aluminum heat exchanger. The heat exchangers may exchange flows A-E that are warmest at HEX_1 and coolest at HEX_6, comparatively. For example, HEX_1 may cool each of flows A-E from top to bottom in the figure as shown. Streams A-E may change the temperature or each other through the heat exchangers HEX_1-6 as shown. For example, each stream A-E may cool down as it moves (e.g., from flow B01) down the figure from HEX_1 through HEX_6 (e.g., to flow B07); then it may warm or heat up as it moves (e.g., from flow B08) up the figure from HEX_6 through HEX_1 (e.g., to flow B14). Each of the beginning flows A01, B01 through E01 may be at ambient temperature (e.g., 50-100 degrees Fahrenheit).

[0032] Each of streams A-E can be or use a different refrigerant or cryogenic liquid. Streams D-E may be or use nitrogen or another cryogenic fluid such as methane. In some cases, stream D is nitrogen and stream E is methane. Using methane in both or a stream may require certain (e.g., temperature and pressure) adjustments for that/those streams, but would work. Streams B-C may be pre-cooled by streams D-E.

[0033] Stream A302 may begin as ambient gaseous hydrogen at flow A01 (the hydrogen input of the system 300) and end as a cooled gaseous hydrogen at flow A07 (the hydrogen output of the system 300) to be sent from the pre-cooling system 300 to a deep cooling system where the cooled hydrogen of flow A07 is liquified.

[0034] The flow from flows B07 to B08, from flow C07 to C08, from flow B14 to B01 and from flow C14 to C01 may be provided by various functions. These functions may be, include or consist of a change of pressure as required for the function of the deep cooling system. These streams may be compressed on the ambient temperature side (e.g., from flow B14 to B01 and from flow C14 to C01) and expanded on the cryogenic side (e.g., B07 to B08 and from flow C07 to C08).

[0035] Flows D01-D14 of stream D310 are composed of primarily nitrogen or methane. Flow D01 is typically ambient temperature (60 to 150 F, or about 125 F) and a moderate pressure (150 to 650 psia, or about 160 psia). In other cases, this moderate pressure may be 150 to 350 psia, or about 160 psia. The flow D01 is cooled through one or more heat exchangers (HEX_1 to HEX_5) to cryogenic (e.g., liquid) temperatures (320 to 270 F, or about 280 F) at flow D06. Cryogenic liquid nitrogen or methane at flow D06 is reduced in pressure across a (e.g., JT) valve V_Cond, wherein the temperature of flow D06 drops due to the Joule-Thompson Effect of that valve to be a two-phase (e.g., liquid and gas) mixture at flow D07 which is directed to one or more heat exchangers (HEX_6 to HEX_1) that warm up flow D07 to vaporize the liquid and heat the fluid to near-ambient conditions at flow D13. The warm flow D13 is then compressed through or by compressor CP_cond to flow D14 which is cooled through or by cooler C_Cond back up to the conditions in flow D01. Compressor CP_cond and cooler C_Cond may represent multiple compressor and cooling stages between flows D14 and D01. In most cases, each compressor and cooler are separate devices, though in some cases they are a combined compressor and cooler device. The compressors herein may be any device or system that increases pressure and the coolers herein may be any device or system that cools liquid and/or gas. The compressors may be centrifugal compressors and the coolers may be a water or air cooler.

[0036] During turndown operation, the temperature and pressures of all flows of D Stream (e.g., all stream D flows D01-D14) may be maintained near their design value.

[0037] During a turndown operation the system 300 is configured to maintain the current temperature and pressure at each flow of D stream while the system runs at a reduced flowrate of the streams A-E to roughly 30% of full load or 100% flowrate which the system is capable of running at. Turndown operation of system 300 may be maintaining the current temperature and pressure at each flow of D stream while the system runs at a reduced flowrate of the streams that is less than 80%, 70% or 30% of full load flowrate. The full load flowrate of the D Steam is determined in the design of the D system in order to provide sufficient refrigeration to streams A-C to reach their targeted temperature.

[0038] During this maintaining of the temperature and pressures of all flows of D stream, only flowrate may be adjusted during the turndown. In this case, because the temperature and pressure at flow D06 is maintained at a fixed point through off design conditions, the flow D06 will always be able to condense to the designed level, ensuring that cold two-phase nitrogen or methane of the flow D07 can always be used to cool Streams A-C to the desired level, such as through or using exchanger HEX_6. Flow D07 may be the coolest or coldest point in stream D or in streams A-E, and may be used to cool all of the streams A-C using exchanger HEX_6. Flow D01 or E01 may be the hottest or warmest point in streams A-E, and may be used to heat all of the streams A-C using exchanger HEX_1.

[0039] In some cases, the turndown operation of system 300 is or includes valve V_Cond lowering the pressure of flow D06, such as by using a globe cavitation trim valve. In some cases, valve V_Cond lowers pressure of flow D06 using a turbo expander.

[0040] This turndown operation of system 300 is achieved through typical means of compressor turndown (Inlet Guide Vanes, Slide Valves, Variable Frequency Drives, Unloaders, or other means depending on compressor technology). Due to the relatively small size of the condensate compressor (D Streams, such as compressor CP_Cond), turndown devices are of significantly reduced cost compared to the incorporation of the same technology (e.g., the required comparable compressors, such as in the E stream, that would be needed to satisfy the function of compressor CP_Cond) on the much larger recycle compressor (e.g., of those required comparable compressors in the E Streams). In some embodiments, even if a turndown device is not used, a recirculation valve may be incorporated with a relatively small impact on overall system efficiency due to the relatively small power draw of this compressor.

[0041] Stream E (such as flows E01-E17 of stream E312) are, include or are composed of primarily nitrogen or methane. Flow E01 is typically ambient temperature (60 to 150 F, or about 125 F) and is high pressure (700 to 1200 psia, or about 1100 psia). The flow E01 is cooled through one or more heat exchangers (HEX_1 for flows E02, E03 and E05; and then as flow E05 through HEX_2 for flow E06). A portion of flow E02 is removed by splitter SP2 at one temperature (0 to 60 F, or about 45 F) as flow E03 and the remainder is removed at a relatively colder temperature (160 to 100 F, or about 155 F) after HEX_ 2 as flow E06. Each of these E03 and E06 flows is fed into one or more expanders X_WTBX and X_CTBX, respectively, which reduce the pressure of the flow (40 to 125 psia, or about 80 psia) and transfers work energy from each of the fluids into a shaft Shaft_W and Shaft_C, respectively, for resulting in compressors CP_WTBB and CP_CTBB in a cooling effect for each flow to become E15 and E17. Flow E07 may be a gas or two-phase mixture (vapor fraction between 0 and 20%, or about 16%). This flow E07 is brought into one or more heat exchangers (HEX_4) where the flow is fully vaporized and warmed to be flow E08 and eventually mixed with Flow E04 by recombiner or mixer M2 to become flow E09. This combined flow as flow E09 is further warmed (HEX_3 to HEX_1) to near ambient temperature (60 to 150 F, or about 120 F) to become flow E12. The flow E12 is then compressed back up to the conditions in flow E01 through multiple compressor stages which may be driven by potentially multiple primary drivers such as motors and expanders. The expanders may perform an inverse operation of a compressor such as by converting change in pressure to (e.g., mechanical spinning of a shaft) work.

[0042] These stages or flows of stream E may include compressor CP_Recycle creating flow E13 from flow E12 and cooler C_Recycle creating flow E14 from flow E13. These stages may include compressor CP_WTBB creating flow E15 from flow E14 and cooler C_WTBB creating flow E16 from flow E15. These stages may include compressor CP_CTBB creating flow E17 from flow E16 and cooler C_CTBB creating flow E01 from flow E17. Compressor CP_WTBB may be driven by or powered mechanically by (e.g., rotating power, work or energy of) spinning shaft Shaft_W of or powered from expander X_WTBX. This compressor CP_WTBB may be powered by the spinning of Shaft_W without any additional electrical power to either that shaft or that compressor CP_WTBB. Compressor CP_CTBB may be powered mechanically by spinning shaft Shaft_C of or powered from expander X_CTBX. This compressor CP_WTBB may be powered by the spinning of Shaft_C without any additional electrical power to either that shaft or that compressor. In some cases, each set of the expander, shaft and compressor are a single device or system. In some cases, each set of the expander, shaft and compressor reduce the electrical power needed to power the system during full flow or turndown.

[0043] In some cases, compressor CP_WTBB, shaft Shaft_W and expander X_WTBX are not present or not used. Here, either flow E03 is not split off at splitter SP2 and flow E04 does not exist (e.g., and mixer M2 does not exist), or flow E04 is the same flow as flow E03; and flow E16 is the same flow as flow E14. In some cases, stream D is only one loop of flows (e.g., flows D01-D13 as shown) cooling only once through one or more of the heat exchangers and heating only once through one or more of the heat exchangers. In this case, stream D is not cooled then heated (or heated then cooled) more than once. In this case, stream D may have only one cooling flow and only one heating flow. In some cases, stream E is only one loop of flows (e.g., flows E01-D13 as shown) cooling only once through one or more of the heat exchangers and heating only once through one or more of the heat exchangers. In this case, stream E is not cooled then heated (or heated then cooled) more than once. In this case, stream E may have only one cooling flow and only one heating flow.

[0044] Also, expander X_WTBX drives Shaft_W using flow E03 as a flow input and flow E04 as a flow output, and the difference in pressure between flow E03 and flow E04 is used to power the Shaft_W. Expander X_WTBX may use pressure of flows E03 and E04, such as higher pressure gas from flow E03 as compared to lower pressure of flow E04, instead of an electrical motor, to drive the Shaft_W. Next, expander X_CTBX drives Shaft_C using flow E06 as a flow input and flow E07 as a flow output, and the difference in pressure between flow E06 and flow E07 is used to power the Shaft_C. Expander X_CTBX may use pressure of flows E06 and E07, such as high pressure gas from flow E06 as compared the lower pressure of flow E07, instead of an electrical motor, to drive the Shaft_C. In some cases, each of the expander, shaft and compressor can be a single device.

[0045] During turndown operation, the mass flow of all flows of E Stream (e.g., all stream E flows E01-E17) may be reduced by reducing the pressures of E stream (e.g., at pressure release valve) by a given percentage for all flows of E Stream. Removing the pressure at one location in stream E will release the pressure for all of stream E and flows of stream E. This reducing the pressures of E stream for or during turndown may lower or reduce the electrical power needed by any or all compressor to perform compression of streams and/or flows during the turndown. This reducing the pressures of E stream for or during turndown may be performed by releasing coolant, cryogenic fluid, nitrogen or methane at any location of stream E, such as at pressure release valve PR at flow E12. This reducing of pressure will lower or reduce the electrical power needed by the motor of compressor CP_Recycle (optionally and/or compressor C-Cond) to perform compression of flow E12 during the turndown. In other cases, increasing the pressures of all flows of E stream after (e.g., or not during turndown or during turnup) may be performed by adding coolant, cryogenic fluid, nitrogen or methane to any location of stream E, such as at flow E12 that will increase the electrical power needed by compressor CP_Recycle (optionally and/or compressor C-Cond) to perform compression of flow E12. That is, stream E has a much larger flow or stream mass than stream D, such as by being larger by 5, 15, 30 or up to 60 the flow of stream D.

[0046] All driven compressors may be designed to maintain a fixed pressure ratio or head change across their stages, streams or flows. This results is a relatively steady volumetric flow and head change through the compression and expansion stages of each stream. Thus, the turndown operating point of each compressor and expander within Stream E will be near the design point, resulting in high efficiency (e.g., higher than prior pre-cooling and liquid hydrogen creating systems) of operation as the equipment turns down. Temperatures are generally maintained near the design values except for flow E07 which may be a two-phase mixture and thus its temperature will drop as the pressure drops. As the mass flow of stream E is reduced in the compressors of that stream, the electrical load of (e.g., needed to power the compressors of stream E) compression drops by approximately the same ratio as the reduction in pressure. Thus, it is possible for the electrical load to be reduced to small percentages of the full load during turndown (e.g., 50% to 20%, or about 30% of the full load). In some cases, the electrical load is reduced to 20%, 30% or 40% of the full load of electrical power needed for power system 300 during turndown. This reduction of electrical load is primarily dictated by flow E12, which must stay above atmospheric pressure to avoid contamination or mechanical issues with that flow.

[0047] System 300 may be the size of a household living room or of a manufacturing building. In general, stream D reacts negatively to changes in pressure but has a positive reaction to changes in flow rate; while comparatively, stream E reacts more positively to changes in pressure but has a more negative reaction to changes in flow rate than stream D. In some cases, stream D has a liquid only flow D07, while stream E has gas in flow E07.

[0048] In some cases, system 300 is or is part of a hydrogen gas liquification system, a liquid hydrogen creation system or a pre-cooling Modified Reverse-Brayton Cycle system. System 300 may be an efficient pre-cooling Modified Reverse-Brayton Cycle hydrogen cooling system. System 300 includes a first stream A302, a second stream B304 and a third stream C306 each including flows A01-A07, B01-B14 and C01-C14 of chemical refrigerant fluid and/or gas (e.g., cryogenic liquid). Each or all these flows may be at a temperature of between in 320 to 425 degrees Fahrenheit (F). Flows B07 and C07 may be fluidly connected or coupled to flows B08 and C08 (respectively) directly or thorough intermediate devices, functions and/or stages. Flows B14 and C14 may be fluidly connected or coupled to flows B01 and C01 (respectively) directly or thorough intermediate devices, functions and/or stages.

[0049] Fourth stream D310 is not mixed with, does not mix fluid or gas with, and is separated from each of the first stream A, the second stream B and the third stream C. The fourth stream D310 is or has a first refrigerant, such as of primarily nitrogen. The first refrigerant may have an ambient temperature of between 60 to 150 degrees F. inclusive and a pressure of between 150 and 600 psia (pounds per square inch absolute) inclusive.

[0050] The fourth stream D310 is cooled through fourth cooling flows D01-D07 by one or more of heat exchangers HEX_1-HEX_5 to cryogenic temperatures in a range of between 320 to 270 degrees F. inclusive, wherein a cryogenic liquid (e.g., nitrogen) first refrigerant flow D06 of the fourth cooling flows is reduced in pressure across a valve V_Cond (e.g., by a Joule-Thomson or J-T valve) such that a temperature of the first refrigerant flow D06 drops to that of cooled flow D07 due to a Joule-Thomson effect of the valve, and a two-phase mixture or flow D07 of or from the first refrigerant flow D06.

[0051] Exchangers HEX_1-HEX_5 may be a subset or first group of the heat exchangers HEX_1-HEX_6 of the system. Flow D07 is then directed to fourth warming flows D07-D13 of the one or more of heat exchangers HEX_6-HEX_1 to vaporize the liquid and heat the fluid of the first refrigerant flow to near-ambient conditions of a second refrigerant flow D13 of the fourth warming flows. The second refrigerant flow D13 (e.g., the vaporized liquid) of the fourth stream is then compressed and cooled through at least one compressor and cooling stage CP_Cond and C_Cond and returned to the fourth cooling flow as flow D01.

[0052] A fifth stream E312 is not mixed with, does not mix fluid or gas with, and is separated from each of the first stream A, the second stream B, the third stream C and the fourth stream D310. No flow of the fifth stream E is mixed with any flow of the fourth stream D. The fifth stream E312 is or has a second refrigerant, such as of primarily nitrogen or methane. The second refrigerant may have an ambient temperature of between 60 to 150 degrees F. inclusive and a high pressure of between 700 and 1200 psia inclusive.

[0053] The fifth stream E312 is cooled through fifth cooling flows E01, E02, E05 and E06 by one or more of heat exchangers HEX_1-HEX_2. A first flow portion E03 of the fifth stream E is removed by a splitter SP2 from a first refrigerant flow E02 of the fifth cooling flows E at a first temperature of between 0 and 60 degrees F. inclusive and a second remainder flow portion E06 of the fifth stream E is removed by the splitter SP2 from the first refrigerant flow E02 at a second and relatively colder temperature than the first temperature of between 160 and 100 degrees F. inclusive.

[0054] The first flow portion E03 feeds into a first expander X_WTBX that mechanically uses a first shaft Shaft_W to power a first compressor CP_WTBB of the fifth chemical stream to increase the pressure of flow E14 or E15 to a pressure of between 400 and 800 psia inclusive. A cooled flow E06 of the second flow portion E06 feeds into a second expander X_CTBX that mechanically uses a second shaft Shaft_C to power a second compressor CP_CTBB of the fifth chemical stream to increase the pressure of flow E17 to the pressure of between 800 and 1200 psia inclusive. In some cases, each of the first flow portion E03 and a cooled flow E06 of the second flow portion E05 of the fifth stream are fed into expanders that mechanically use a shaft to power fifth compressors to reduce the temperature of the fifth stream to serve as the fifth warming flows (E04, E09, E10, E11 and E12) and flows (E07, E08, E09, E10, E11 and E12), respectively. In some cases, each of the first flow portion E03 and a cooled flow E06 are fed into expanders that mechanically use a shaft to power fifth compressors to reduce the temperature of the fifth stream to serve as the fifth warming flows (E09, E10 and E11) and flows (E08, E09, E10 and E11), respectively.

[0055] In some cases, each expander X_WTBX and X_CTBX transfers work energy from fluid of each of the flows E03 and E06 respectively, into the shafts Shaft_W and Shaft_C which powers the fifth compressors, resulting in a cooling effect of the E04 and E07 flows.

[0056] In some cases, a first flow portion E03 of the fifth chemical stream is feed into a first expander that mechanically uses a first shaft to power a first compressor of the fifth chemical stream to reduce a temperature of the fifth stream to serve as a stream first flow portion (e.g., flows E04, E09, E10, E11 and E12; or flows E09, E10 and E11) of the fifth warming flow. Also, a cooled flow E06 of the second flow portion of the fifth chemical stream may feeds into a second expander that mechanically uses a second shaft to power a second compressor of the fifth chemical stream to reduce the temperature of the fifth stream to serve as a stream second flow portion (e.g., flows E07, E08, E09, E10, E11 and E12; or flows E08, E09, E10 and E11) of the fifth warming flow.

[0057] A third flow portion E07 of the fifth stream E07, as a gas or two-phase mixture is brought into fifth warming flows E07-E12 of the one or more heat exchangers HEX_4-HEX_1, where the third flow portion E07 is fully vaporized and warmed to be flow E08, which is then mixed with a fourth flow portion E04 of the fifth stream by a mixer M2 such that a mixed stream flow E09 is further warmed by a part of the one or more heat exchangers HEX_3-HEX_1 to the near ambient temperature of between 60 and 150 degrees F. inclusive. The mixed stream E09 is then compressed and cooled through at least one compressor and cooling stage CP_ Recycle and C_Recycle and sent as flow E14 to an input of a fifth compressor CP_WTBB.

[0058] Compressor CP_WTBB outputs flow E15 to at least one cooling stage C_WTBB and from there as flow E16 as an input of a fifth compressor CP_CTBB. Compressor CP_CTBB outputs flow E17 cooled through at least one cooling stage C_CTBB and sent as flow E01 to exhanger HEX_1 which is cooled to be flow E02.

[0059] Flow E03 may be used as a flow input and flow E04 as a flow output to expander X_WTBX, and the difference in pressure or power between flow E03 and flow E04 is used to power the Shaft_W. Flow E06 may be used as a flow input and flow E07 as a flow output to expander X_CTBX, and the difference in pressure or power between flow E06 and flow E07 is used to power the Shaft_C. In some cases, E04 and E07 are the flow outputs of the expanders after pressure, energy or power is used from flow inputs E03 and E06 to create spinning of the shafts W and C.

[0060] During a turndown operation of the system 300, a mass flow of the fifth stream E is reduced by reducing pressure (e.g. at pressure release valve PR) of the second refrigerant by a given or selected percentage that is based on the percentage or amount of flowrate turndown desired. During the turndown operation the system 300 may run at a reduced flowrate at or below 30% or 70% of a full load flowrate the system is capable of. During the turndown operation, a pressures of the fifth stream E may be reduced by releasing coolant, cryogenic fluid, nitrogen or methane of the fifth stream E, such as at flow E12 to lower or reduce the electrical power needed by compressor CP_Recyle (and optionally compressor CP_Cond) to perform compression of the fifth stream E. Reducing pressures of the second refrigerant may include maintaining a fixed pressure ratio or head change across stages of the fifth stream E resulting in a relatively steady volumetric flow and head change through the compression and expansion stages of stream E resulting in high efficiency of operation with a reduced electrical load for stream E and/or system 300.

[0061] FIG. 3B is a drawing of another efficient hydrogen cooling system 350. System 350 is the same as system 300, except that system 350 has streams E352 that splits (e.g., at splitter SP3) flow E20 from E01 directly to X_WTBX which is then heated in HEX_01 and mixed with flow E10 (e.g., mixed with flow E22 at mixer M3). The pressure at E20 now is higher than that of E04, requiring a compressor CP_Recycle to equalize the pressures prior to mixing and further compression CP_Recycle2. This arrangement beneficially reduces the volumetric flows required to be handled by CP_Recycle.

[0062] In system 350, a fifth stream E352 is not mixed with, does not mix fluid or gas with, and is separated from each of the first stream A, the second stream B, the third stream C and the fourth stream D310. No flow of the fifth stream E is mixed with any flow of the fourth stream D. The fifth stream E352 is or has a second refrigerant, such as of primarily nitrogen or methane. The second refrigerant may have an ambient temperature of between 60 to 150 degrees F. inclusive and a high pressure of between 700 and 1200 psia inclusive.

[0063] The fifth stream E352 is cooled through fifth cooling flows E01, E02 and E03 by one or more of heat exchangers HEX_1-HEX_2. Flow E03 feeds into a second expander X_CTBX that mechanically uses a second shaft Shaft_C to power a second compressor CP_CTBB of the fifth chemical stream to increase the pressure of flow E15, which may be increased to a pressure of between 400 and 800 psia inclusive, to be flow E16. Flow E20 feeds into a first expander X_WTBX that mechanically uses a first shaft Shaft_W to power a first compressor CP_WTBB of the fifth chemical stream to increase the pressure of flow E13, which may be increased to a pressure of between 400 and 800 psia inclusive, to be flow E14.

[0064] In some cases, each of the flow E03 and E20 of the fifth stream are fed into expanders that mechanically use a shaft to power fifth compressors to reduce the temperature of the fifth stream to serve as the fifth warming flows (E04-E08) and flows (E21-E22), respectively. In some cases, each of the first flow portion E03 and a cooled flow E20 are fed into expanders that mechanically use a shaft to power fifth compressors to reduce the temperature of the fifth stream to serve as the fifth warming flows (E05-E07) and flow (E21), respectively.

[0065] In some cases, each expander X_WTBX and X_CTBX transfers work energy from fluid of each of the flows E20 and E03 respectively, into the shafts Shaft_W and Shaft_C which powers the fifth compressors, resulting in a cooling effect of the E21 and E04 flows, respectively.

[0066] In system 350, flow E04, as a gas or two-phase mixture is brought into fifth warming flows E05-E08 of the one or more heat exchangers HEX_4-HEX_1, where the flow E04 is fully vaporized and warmed to the near ambient temperature of between 60 and 150 degrees F. inclusive. The near ambient stream E08 is then compressed and cooled through at least one compressor and cooling stage CP_ Recycle and C_Recycle and sent as flow E10.

[0067] Flow E21 is brought into fifth warming flows E21-E22 of the one or more heat exchangers, to become warmed flow E22. Flows E10 and E22 are mixed by a recombiner or mixer M3 to become flow E11. Flow E11 is further compressed and cooled through at least one compressor and cooling stage CP_ Recycle2 (which may have feedback flow E12) and C_Recycle2 and sent as flow E13 as an input to fifth compressor CP_WTBB.

[0068] In system 350, compressor CP_WTBB outputs flow E14 to at least one cooling stage C_WTBB and from there as flow E15 as an input of a fifth compressor CP_CTBB. Compressor CP_CTBB outputs flow E16 cooled through at least one cooling stage C_CTBB and sent as flow E01 to a splitter SP3 to be split into flow E20 and flow E23 which is sent to exhanger HEX_1 and cooled to be flow E02.

[0069] Flow E20 may be used as a flow input and flow E21 as a flow output to expander X_WTBX, and the difference in pressure or power between flow E20 and flow E21 is used to power the Shaft_W. Flow E03 may be used as a flow input and flow E04 as a flow output to expander X_CTBX, and the difference in pressure or power between flow E03 and flow E04 is used to power the Shaft_C. In some cases, E21 and E04 are the flow outputs of the expanders after pressure, energy or power is used from flow inputs E20 and E03 to create spinning of the shafts W and C.

[0070] During a turndown operation of the system 350, a mass flow of the fifth stream E is reduced by reducing pressure (e.g. at pressure release valve PR) of the second refrigerant by a given or selected percentage that is based on the percentage or amount of flowrate turndown desired. During the turndown operation the system 350 may run at a reduced flowrate at or below 30% or 70% of a full load flowrate the system is capable of. During the turndown operation, a pressures of the fifth stream E may be reduced by releasing coolant, cryogenic fluid, nitrogen or methane of the fifth stream E, such as at flow E08 to lower or reduce the electrical power needed by compressor CP_Recyle (and optionally compressor CP_Cond and/or compressor CP_Recyle2) to perform compression of the fifth stream E. Reducing pressures of the second refrigerant may include maintaining a fixed pressure ratio or head change across stages of the fifth stream E resulting in a relatively steady volumetric flow and head change through the compression and expansion stages of stream E resulting in high efficiency of operation with a reduced electrical load for stream E and/or system 350.

[0071] In some cases, the first refrigerant of stream D is not the same refrigerant as the second refrigerant of stream E. None of the liquid, gas or chemical in the fourth stream D is combined or mixed with any of that of the fifth stream E. In some cases, the first refrigerant and the second refrigerant are each one of nitrogen, methane, a hydrocarbon, oxygen, hydrogen, helium, or a mixture of these molecules. In some cases, each of the first stream A, the second stream B and the third stream C include one of product hydrogen, product methane; or refrigerants selected from one of hydrogen, helium, and neon or blends of multiple of those refrigerants.

[0072] Alternative configurations include that the E loop's expander outlets are at different pressures. It is also understood that a different number of expanders operate in series or parallel within the E circuit. It is also understood that the expanders may drive other devices such as a motor or gearbox with multiple loads.

[0073] Alternative configurations include the refrigerant in either streams D or E are not primarily nitrogen but may be light hydrocarbons, oxygen, hydrogen, helium, or mixtures of these molecules.

Description of Methods

[0074] Referring now to FIG. 4, a process 400 for efficient hydrogen cooling starts at 405 and ends at 495. The process 400 may be executed by system 300 or 350. In some cases, process 400 is or is part of a method of hydrogen gas liquification, liquid hydrogen creation and/or modified pre-cooling Modified Reverse-Brayton Nitrogen Cycling.

[0075] The process 400 includes step 405 of providing a first stream A, a second stream B and a third stream C each including flows A01-A07, B01-B14 and C01-C14 of refrigerant at a temperature of between in 320 to 425 degrees Fahrenheit (F). Step 405 is providing the steams A, B and C of fluid and/or gas refrigerant or cryogenic liquid include product hydrogen and refrigerants, such as hydrogen, helium, or neon, or blends of multiple refrigerants. Step 405 may be providing the steams A, B and C as noted in descriptions for FIGS. 3A-3B.

[0076] Step 410 is providing a fourth stream D having a first refrigerant (such as of primarily nitrogen) having an ambient temperature of between 60 to 150 degrees F. and a pressure of between 150 to 600 psia. The fourth stream may be separate from each of the first stream A, the second stream B and the third stream C. Step 410 may be providing a fourth stream D not mixed with any of the first A, second B or third C streams. Step 410 may be providing the stream D as noted in descriptions for FIGS. 3A-3C.

[0077] Step 420 is cooling the fourth stream D through fourth cooling flows by one or more heat exchangers to cryogenic temperatures in a range of between 320 to 270 degrees F. Cooling flows D01-D06 of the fourth stream D through fourth cooling flows D01-D07 by one or more heat exchangers HEX_1 through HEX_5. Step 420 may be cooling the stream D through fourth cooling flows as noted in descriptions for FIGS. 3A-3C.

[0078] Step 430 is reducing pressure of the first refrigerant flow across a Joule-Thomson (JT) valve such that a temperature of that flow drops based on a Joule-Thomson effect of that valve. The valve may be a JT valve that reduces pressure of a cryogenic liquid first refrigerant flow D06 such that a temperature of that flow drops due to a Joule-Thomson effect to become flow D07. Step 430 may be reducing pressure of the first refrigerant flow through a JT valve V_Cond as noted in descriptions for FIGS. 3A-3C.

[0079] Step 440 is directing a two-phase mixture of the reduced pressure flow D07 of the first refrigerant flow D06 to fourth warming flows D07-D13 of the one or more heat exchangers HEX_6 through HEX_1. Directing the two-phase mixture D7 of the reduced pressure flow may be directing flow D07 to fourth warming flows D07-D13 of the one or more heat exchangers HEX_6 through HEX_1 to vaporize the liquid and heat the fluid of the first refrigerant flow D07 to near-ambient conditions of flow D13. Step 440 may be directing a two-phase mixture of the reduced pressure flow D07 as noted in descriptions for FIGS. 3A-3C.

[0080] Step 440 may also or optionally include compressing and cooling the second refrigerant flow D13 of the fourth stream through at least one compressor and cooling stage. This compressing and cooling flow D13 may be through compressor CP_Cond as flow D 14 and then through cooler C_Cond to return it as flow D01 the fourth cooling flow. This may be compressing and cooling flow D13 to be flow D01 as noted in descriptions for FIGS. 3A-3C.

[0081] Step 450 is providing a fifth stream E not mixed with any of the first A, second B, third C or fourth D streams. Fifth stream E may have a second refrigerant having the ambient temperature of between 60 to 150 degrees F. and a high pressure of between 700 and 1200 psia. Providing the fifth stream E may be providing a fifth stream E not mixed with each or any of the streams A-D. The fifth stream has a second refrigerant (such as of primarily nitrogen) having the ambient temperature of between 60 to 150 degrees F. and a high pressure of between 700 and 1200 psia. Step 450 may be providing a fifth stream E as noted in descriptions for FIGS. 3A-3C. In some cases, the first refrigerant is not the same as the second refrigerant. In some cases, the first refrigerant is the same as the second refrigerant. In some cases, none of the liquid, gas or chemical in the fourth stream D is combined or mixed with that of the fifth stream E.

[0082] Step 460 is cooling the fifth stream E through fifth cooling flows E02, E03, and E06 by the one or more heat exchangers. Cooling flow E01 may be cooled to be or through fifth cooling flows E02, E03, E05 and E06 by the one or more heat exchangers HEX_1 to HEX_2. Cooling the fifth stream E may be cooling flow E01 through exchanger HEX_1 to be flow E02, splitting flow E02 by splitter SP2 into flow E03 and into flow E05 which is cooled by exchanger HEX_2 to be flow E06. Step 460 may be cooling fifth stream E as noted in descriptions for FIGS. 3A-3C.

[0083] Step 470 is removing a first flow portion E03 of the fifth stream E from a first refrigerant flow E02 by a splitter SP2 to be at a first temperature of between 0 and 60 degrees F. The removing of flow E03 may be removing a portion of the flow E02 of by splitter SP2 to be first removed flow portion E03. Step 470 may be removing flow E03 as noted in descriptions for FIGS. 3A-3C.

[0084] Step 480 is removing a second remainder flow portion E05 of the fifth stream E from the first refrigerant flow E02 by the splitter SP2 to be at a second and relatively colder temperature (compared to the temperature of flow E03) of between 160 to 100 F. Removal of the second remainder flow portion may be removing a portion of the flow E02 of by splitter SP2 to be second removed flow portion E05. Flow E05 is cooled by exchanger HEX_2 to be cooled flow E06. Step 480 may be removing flow E05 and cooling it to be flow E06 as noted in descriptions for FIGS. 3A-3C.

[0085] Step 490 is feeding each of the first flow portion E03 and a cooled flow E06 of the second remainder flow portion E05 after HEX_2 into expanders X_WTBX and X_CTBX, respectively, transferring work energy from fluid of each of the first flow portion E03 and the cooled flow E06 into a shafts Shaft_W and Shaft_C which may power the fifth compressors CP_WTBB and CP_CTBB, respectively. Transfering the work energy results in a cooling effect of the flows E04 and E07 of stream E312 which are warmed in HEX_1-4. Step 490 may be feeding and transferring as noted in descriptions for FIGS. 3A-3C.

[0086] Step 490 may be feeding each of the first flow portion E03 and a cooled flow E06 of the second remainder flow portion E05 after HEX_2 into expanders X_WTBX and X_CTBX, respectively, that mechanically power the fifth compressors CP_WTBB and CP_CTBB to reduce a temperature of the fifth stream to serve as fifth warming flows, such as flows (E04, E09, E10, E11 and E12) and flows (E07, E08, E09, E10, E11 and E12), respectively.

[0087] In some cases, step 490 is or includes feeding a first flow portion E03 of the fifth chemical stream into a first expander that mechanically uses a first shaft to power a first compressor of the fifth chemical stream to reduce a temperature of the fifth stream E to serve as a stream first flow portion E04-E12 of the fifth warming flow. Step 490 may also be or include feeding a cooled flow E06 of the second flow portion of the fifth chemical stream into a second expander that mechanically uses a second shaft to power a second compressor of the fifth chemical stream to reduce the temperature of the fifth stream E to serve as the second flow portion E07-E12 of the fifth warming flow.

[0088] Step 495 may optionally include performing a turndown operation of the system. Performing a turndown operation of the system may include reducing a mass flow of the fifth stream E by reducing pressure of the second refrigerant (e.g., at pressure release valve) by a given or selected percentage that is based on the percentage or amount of desired turndown flowrate. The turndown operation may include reducing a system flowrate (e.g., of stream E) to (e.g., the system is configured to run at a power, electricity and/or renewable energy that provides) below 30% or 70% or 80% of a full load flowrate the system is capable of running at. The turndown operation may include reducing pressures of the fifth stream E by releasing coolant, cryogenic fluid or nitrogen of the fifth stream to lower electrical power needed by a compressor (e.g., centrifugal compressor CP_Recycle) to perform compression of flow E12 at pressure release valve PR of the fifth stream. Step 495 may be performing turndown as noted in descriptions for FIGS. 3A-3C.

[0089] Steps 490 or 495 may return to step 405 as shown by the arrows. In some cases, any step may return or proceed to any other step of process 400.

[0090] The steps of process 400 may all be performed simultaneously or at the same time or over the same period of time (such as over minutes, an hour, a few hours or a dozen hours. In other cases, they may occur in order of their step numbers.

[0091] A process similar to process 400 for system 300 may be performed for system 350.

[0092] System 300, system 350 and/or process 400 may be controlled by computer hardware and/or software. They may be controlled by non-transitory medium storing computer instructions that when executed by a processor cause a computer to perform and/or perform control of system 300, system 350 and/or process 400.

Closing Comments

[0093] Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and procedures disclosed or claimed. 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. With regard to flowcharts, additional and fewer steps may be taken, and the steps as shown may be combined or further refined to achieve the methods described herein. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments.

[0094] As used herein, plurality means two or more. As used herein, logic may be or include hardware and/or software needed to perform the function described for the logic. As used herein, a set of items may include one or more of such items. As used herein, whether in the written description or the claims, the terms comprising, including, carrying, having, containing, involving, and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases consisting of and consisting essentially of, respectively, are closed or semi-closed transitional phrases with respect to claims. Use of ordinal terms such as first, second, third, etc., 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 the claim elements. As used herein, and/or means that the listed items are alternatives, but the alternatives also include any combination of the listed items.