JP2024511600A - System and method for precooling in hydrogen or helium liquefaction processing - Google Patents

Abstract

Systems and processes are described herein for precooling hydrogen or helium gas streams for liquefaction using liquid nitrogen, with reduced energy consumption and liquid nitrogen usage. The system includes a stream of pressurized liquid nitrogen, at least one turboexpander, and at least one heat exchanger. [Selection diagram] Figure 1

Description

This disclosure relates to a pre-cooling process using liquid nitrogen in the liquefaction of hydrogen or helium. More specifically, the present disclosure relates to a method for precooling hydrogen or helium gas using a process based on the supply of liquid nitrogen, the method comprising at least one turboexpander and one or more heat exchangers. These work together to reduce the amount of nitrogen required for pre-cooling and reduce the energy consumed in the pre-cooling process.

Liquefaction of hydrogen and helium requires large consumption of energy. Hydrogen has the second lowest boiling point of all substances, boiling at -253°C at atmospheric pressure. Only helium has a lower boiling point. The liquefaction process is divided into several stages such as hydrogen compression, pre-cooling, and liquefaction. In the pre-cooling stage of hydrogen liquefaction, hydrogen gas may be cooled from ambient temperature to approximately -191°C. Large-scale hydrogen liquefiers utilize liquid nitrogen supplied from an associated nitrogen/air liquefaction plant. Hydrogen and helium liquefaction processes frequently use liquid nitrogen for pre-cooling purposes in the liquefaction process. The use of liquid nitrogen reduces the overall energy requirements in the production of liquid hydrogen or liquid helium. Furthermore, the liquid nitrogen obtained for this application is produced separately with considerable energy consumption. Direct evaporation of liquid nitrogen, conventionally supplied at low pressure and low temperature for evaporation and superheating, as a means of pre-cooling the hydrogen or helium prior to liquefaction, is a method of combining a hot hydrogen or helium fluid with a cold nitrogen fluid. Requires a large temperature difference between

FIG. 5 is an example of a conventional pre-cooling treatment of hydrogen gas with liquid nitrogen (500). Liquid nitrogen (LIN) is provided in stream (504) and hydrogen gas (warm or ambient temperature) is provided in stream (501). A stream of liquid nitrogen (504) and a stream of hydrogen gas (501) flow in opposite directions through a heat exchanger (502), resulting in a cooled stream of hydrogen gas (503) and a stream of warmed nitrogen gas (505). The conditions of the liquid nitrogen supplied are typical of those produced by cryogenic air separation plants.

The pre-cooling process directly impacts the overall energy required for hydrogen or helium liquefaction. The energy required for pre-cooling, represented by the energy to produce the required liquid nitrogen, is a significant portion of the total energy for liquefying liquid hydrogen or helium. Recent research has focused on means to reduce the overall energy required to liquefy hydrogen or helium by various means to provide pre-cooled refrigeration, and on means to reduce the amount of liquid nitrogen required. I have combined it.

A method of precooling hydrogen or helium gas prior to liquefaction using a stream of liquid nitrogen is disclosed. This method consists of a. ) providing a pressurized liquid nitrogen stream containing liquid nitrogen at a pressure of about 15 bar(a) to about 70 bar(a); b. ) passing the pressurized liquid nitrogen stream and the partially cooled hydrogen or helium gas stream through a first heat exchanger that exchanges heat between the pressurized liquid nitrogen stream and the partially cooled hydrogen or helium gas stream; obtaining a partially warmed nitrogen stream and a pre-cooled hydrogen or helium gas stream; c. ) passing a first partially warmed nitrogen stream through one or more turboexpanders that reduce the temperature and pressure of the partially warmed nitrogen stream to obtain a cold nitrogen stream; d. ) passing the cold nitrogen stream through a first heat exchanger and a second heat exchanger to obtain a pre-cooled hydrogen or helium gas stream and a fully warmed nitrogen gas stream. Step (d) includes passing the cold nitrogen stream through a first heat exchanger that exchanges heat between the cold nitrogen stream and the partially cooled hydrogen or helium gas stream to the second partially warmed nitrogen gas stream and the precooled nitrogen gas stream. a second heat exchanger for exchanging heat between the second partially heated nitrogen gas stream and the heated hydrogen or helium gas stream; passing a nitrogen gas stream to obtain a fully warmed nitrogen gas stream and a partially cooled hydrogen or helium gas stream. The first heat exchanger and the second heat exchanger may be separate devices or two parts within one heat exchanger. The method may further include utilizing a supplemental refrigeration system coupled to the second heat exchanger.

Step (a) includes providing a stream of liquid nitrogen produced at a saturation pressure of less than about 10 bar(a) and subsequently increasing the pressure of the stream of liquid nitrogen to obtain a pressurized stream of liquid nitrogen. But that's fine. Step (a) comprises providing a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a); and increasing the pressure of the first portion of the liquid nitrogen stream to obtain a pressurized liquid nitrogen stream. The second portion of the liquid nitrogen stream may pass through the first heat exchanger to obtain a third partially heated nitrogen stream. The third partially warmed nitrogen stream can be passed through a second heat exchanger to obtain a second fully warmed nitrogen gas stream. Pressurized liquid nitrogen has a pressure of about 15 bar(a) to about 70 bar(a), or about 20 bar(a) to about 55 bar(a).

The pressurized liquid nitrogen stream may be split into a first pressurized liquid nitrogen stream and a second pressurized liquid nitrogen stream, the first pressurized liquid nitrogen stream and the second pressurized liquid nitrogen stream and a first heat exchanger for exchanging heat between the first and second pressurized liquid nitrogen streams and the partially cooled hydrogen or helium gas stream.

a. ) providing a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a); b. ) directing a first portion of the liquid nitrogen stream to a first heat exchanger to obtain a first partially warmed nitrogen stream; c. ) directing the first partially warmed nitrogen stream to a second heat exchanger to obtain a first fully warmed nitrogen gas stream; c. ) increasing the pressure of the second portion of the liquid nitrogen stream to obtain a pressurized liquid nitrogen stream at a pressure of about 15 bar(a) to about 70 bar(a); d. ) passing a pressurized liquid nitrogen stream and a partially cooled hydrogen or helium gas stream in opposite directions through a first heat exchanger to obtain a second partially warmed nitrogen gas stream and a precooled hydrogen or helium gas stream; step; e. ) passing the second partially heated nitrogen gas stream through a second heat exchanger that exchanges heat between the second partially warmed nitrogen gas stream and the warm hydrogen or warm helium gas stream; obtaining a nitrogen gas stream and a partially cooled hydrogen or helium gas stream; f. ) passing a second fully warmed nitrogen gas stream through one or more turboexpanders that reduce the temperature and pressure of the second fully warmed nitrogen gas stream to obtain a cold nitrogen stream; e. ) A third partially warmed nitrogen gas stream and a pre-cooled hydrogen or helium stream are passed through a first heat exchanger that exchanges heat between the cold nitrogen stream and a partially cooled hydrogen or helium gas stream. obtaining a gas flow; f. ) passing a third partially heated nitrogen gas stream through a second heat exchanger that exchanges heat between the third partially heated nitrogen gas stream and a warm hydrogen or warm helium gas stream; Another method for precooling hydrogen or helium gas using a liquid nitrogen stream is disclosed, the method comprising obtaining a nitrogen gas stream and a partially cooled hydrogen or helium gas stream. Step (g) includes passing the second fully warmed nitrogen stream through one or more compressors and one or more turboexpanders before passing the second fully warmed nitrogen stream through the one or more turboexpanders. It may also include a step of passing through a cooler. Step (g) may include passing the second fully warmed nitrogen stream through two turboexpanders connected in series. The method may further include utilizing a supplemental refrigeration system coupled to the second heat exchanger.

The pressurized liquid nitrogen stream may be split into a first pressurized liquid nitrogen stream and a second pressurized liquid nitrogen stream; the first pressurized liquid nitrogen stream and the second pressurized liquid nitrogen stream are separately The heat exchanger may be passed through the first heat exchanger, and in some cases, it may be passed through the second heat exchanger.

The method may include a system for recooling the second or third fully warmed nitrogen gas stream, the system for recooling comprising i. ) passing the second or third fully warmed nitrogen gas stream through a first compressor and a first cooler to obtain a compressed and cooled nitrogen gas stream, the first compressor a second heat exchanger and a first cooler; ii. ) passing the compressed and cooled nitrogen gas stream through one or more turboexpanders; iii). passing the turbo-expanded nitrogen gas stream through a second heat exchanger to obtain a fourth fully warmed nitrogen gas stream. Step (ii) includes passing the compressed and cooled nitrogen gas stream through two turboexpanders connected in series.

A pre-cooling system using liquid nitrogen for hydrogen or helium liquefaction is also disclosed. The system comprises: a stream of warm hydrogen or helium gas; a stream of pressurized liquefied nitrogen from a source of liquefied nitrogen; a heat exchanger; a partially heated nitrogen gas coupled to the heat exchanger and discharged from the heat exchanger. and at least one turboexpander configured to reduce the temperature of the stream. The heat exchanger exchanges heat between the pressurized liquefied nitrogen stream and the warm hydrogen or warm helium gas stream to increase the temperature of the pressurized liquefied nitrogen stream and decrease the temperature of the hot hydrogen or warm helium gas stream. , a pre-cooled hydrogen or helium gas stream, and a warm nitrogen gas stream. In another aspect, the system exchanges heat between a pressurized liquefied nitrogen stream and a partially cooled hydrogen or helium gas stream to increase the temperature of the pressurized liquefied nitrogen stream to form a partially warmed nitrogen gas stream. a first heat exchanger configured to reduce the temperature of the partially heated hydrogen or helium gas stream; at least one heat exchanger configured to reduce the temperature of the partially warmed nitrogen gas stream; a turboexpander; exchanging heat between a partially warmed nitrogen gas stream and a hot hydrogen or warm helium gas stream to increase the temperature of the partially warmed nitrogen gas stream to obtain a fully warmed nitrogen gas stream; a second heat exchanger configured to reduce the temperature of the hot hydrogen or hot helium gas stream.

The system also includes at least one compressor and at least one cooler configured to receive the warm nitrogen gas stream discharged from the heat exchanger, after passing through the at least one compressor and at least one cooler. It may also include at least one turboexpander configured to receive a flow of warm nitrogen gas, and/or optionally a valve coupled to the turboexpander.

1 is a schematic diagram of a system for pre-cooling hydrogen gas using liquid nitrogen, first and second heat exchangers, a turbo expander, and supplemental refrigeration. FIG. 1 is a schematic diagram of a system for precooling hydrogen gas using liquid nitrogen, first and second heat exchangers, a turbo expander, supplemental refrigeration, and other components. FIG. 1 is a schematic diagram of a system for precooling hydrogen gas using liquid nitrogen, first and second heat exchangers, multiple turboexpanders, multiple compressors, multiple coolers, auxiliary refrigeration, and other components; be. 1 is a schematic diagram of a system for precooling hydrogen gas using liquid nitrogen, first and second heat exchangers, two turboexpanders, two compressors, two coolers, and other components. be. 1 is a schematic diagram of a conventional system for precooling hydrogen or helium gas using liquid nitrogen; FIG.

The process disclosed herein was developed to reduce to some extent the amount of liquid nitrogen required to pre-cool hydrogen or helium gas in the liquefaction process. These processes and pre-cooling systems employ additional steps and equipment to more fully utilize the amount of liquid nitrogen supplied to the pre-cooling system. That is, externally derived liquid nitrogen is consumed at a lower flow rate compared to conventional precooling systems. It is also understood that if liquid nitrogen is also used to pre-cool other hydrogen or helium streams used in the liquefaction process (so-called recycle streams), measures to reduce the consumption of liquid nitrogen there are also applicable. be done.

In the method disclosed herein for precooling hydrogen or helium gas using a stream of liquid nitrogen, the liquid nitrogen feed is pressurized to increase its cooling capacity in heat exchange with the hydrogen or helium gas. The heated nitrogen is then mechanically expanded to a lower temperature and reintroduced for heat exchange with hydrogen or helium. In fact, the supplied liquid nitrogen passes through the same heat exchanger a second time (within the loop), thus reducing the amount of liquid nitrogen required and the associated energy required for its production. The energy costs for producing this reduced amount of liquid nitrogen are thereby reduced. The overall cost of liquefaction is reduced, which is of commercial importance, since this cost is a significant component of the energy cost for producing liquid hydrogen or liquid helium. The cost of pre-cooling can be reduced by about 20% to about 50%.

As used herein, the term "mechanically expanding" includes any device that is utilized to produce work by reducing the enthalpy of the fluid being expanded, such as a turboexpander or a reciprocating engine.

In conventional liquid nitrogen precooling processes for hydrogen, the liquid nitrogen consumption is about 7 to about 10 kg of liquid nitrogen per kg of liquid hydrogen. In the pre-cooling process disclosed herein, liquid nitrogen consumption can be from about 4 to about 6 kg of liquid nitrogen per kg of liquid hydrogen, or from about 4.30 to about 5.35 kg of liquid nitrogen. This is a significant reduction in liquid nitrogen consumption over conventional processes.

A method is disclosed for precooling hydrogen or helium gas using a stream of liquid nitrogen, whereby an overall reduction in the amount of liquid nitrogen is used compared to conventional precooling.

The method includes a pressurized liquid nitrogen stream that can have a pressure of about 15 bar(a) to about 70 bar(a), about 20 bar(a) to about 60 bar(a), or 20 bar(a) to about 50 bar(a). including the steps of preparing. The pressurized liquid nitrogen may have a temperature of about -147°C to about -196°C, about -169°C to about -195°C, or about -189°C to about -194°C.

Pressurized liquid nitrogen may be supplied directly to the methods disclosed herein. Alternatively, liquid nitrogen may be supplied from an external source having a saturation pressure of about 1 bar(a) to about 10 bar(a), which may then be pressurized by any means known in the art. Liquid nitrogen may be pressurized by utilizing a pump or by compressing to increase pressure.

In one embodiment, the pressurized liquid nitrogen stream may be split into a first pressurized liquid nitrogen stream and a second pressurized liquid nitrogen stream, the first pressurized liquid nitrogen stream and the second pressurized liquid nitrogen stream. Each of the nitrogen streams may be directed through a first heat exchanger to exchange heat between each of the first and second pressurized liquid nitrogen streams and the partially cooled hydrogen or helium gas stream. good. The two partially warmed nitrogen streams passed separately through the first heat exchanger may be combined into a single stream before being directed through the at least one turboexpander.

In one embodiment, a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a) is provided to the system, and the first portion of the liquid nitrogen stream and the second (or remaining) portion of the liquid nitrogen stream are Divert the flow. The first portion of the liquid nitrogen stream may have increased pressure by any means known in the art, such as by pumping or compression, to obtain a pressurized liquid nitrogen stream. A second portion of the pressurized liquid nitrogen stream may be conducted separately from the path of the pressurized liquid nitrogen stream to the first heat exchanger and then optionally to the second heat exchanger.

As used herein, "pump" refers to a mechanical device that increases the pressure of a liquid.

A hot hydrogen or helium gas stream is provided for pre-cooling and may be provided from one or more hydrogen or helium feed streams or from a circulating hydrogen or helium feed stream. The hot hydrogen gas stream may be produced from natural gas, water electrolysis, or other chemical methods. The hot hydrogen or helium gas stream may be supplied from a source external to the liquefaction process, or may be a recycle stream from other parts within the process. The hot hydrogen gas stream may be at any pressure suitable for its final liquefaction. The hot hydrogen gas stream may have a pressure of about 20 bar(a) to about 80 bar(a), or about 20 bar(a) to about 40 bar(a), and/or about 25°C to about 35°C. It may have a temperature of The warm hydrogen gas stream may have a composition of about 75% ortho and about 25% para spin isomers.

Ortho-para conversion of hydrogen gas may be incorporated as the hydrogen gas is cooled. The ortho-para conversion may take place in the first heat exchanger and in the second heat exchanger, the passage of the heat exchanger(s) optionally being filled with a catalyst for the feed hydrogen. There is. The catalyst may be any known for use in the art for this purpose. This may improve the overall energy efficiency of the liquefaction process. The pre-cooled hydrogen gas stream has a temperature of from about -173°C to about -196°C, from about -180°C to about -196°C, or from about -190°C to about -192°C, and/or from about 15 bar(a) to It may have a pressure of about 100 bar(a), or from about 20 bar(a) to about 80 bar(a). The pre-cooled hydrogen gas stream may be about 53% ortho and about 47% para.

As used herein, "heat exchanger" refers to any device capable of transferring thermal or cold energy from one medium to another, such as between at least two separate fluids. means. Heat exchangers include "direct heat exchangers" and "indirect heat exchangers". The heat exchanger may therefore be of any suitable design, for example a co-current or counter-current heat exchanger, an indirect heat exchanger (e.g. a spiral heat exchanger, or a plate fin heat exchanger such as a blazed aluminum plate fin type). , direct contact heat exchanger, shell and tube heat exchanger, spiral type, hairpin type, core type, core and kettle type, printed circuit type, double tube type, etc., or any other type of known heat exchanger. It may be.

As used herein, a first heat exchanger transfers energy between opposing streams in the cooling step of the process, while a second heat exchanger transfers energy between opposing streams in the heating section of the process. transfer energy between A pre-cooled hydrogen or helium gas stream exits the first heat exchanger, while a fully warmed nitrogen gas stream exits the second heat exchanger. The first and second heat exchangers may be two parts of one heat exchanger, or they may be two separate heat exchangers. When the first and second heat exchangers are two parts of one heat exchanger, the heat exchanger includes multiple outlets for flow therethrough, including, but not limited to, various outlets of the unit. The location of the valve's exit point is mentioned.

As used herein, the term "indirect heat exchange" means bringing two fluids into a heat exchange relationship without physical contact or mixing of the fluids with each other. Core-in-kettle heat exchangers and blazed aluminum plate fin heat exchangers are examples of devices that promote indirect heat exchange.

The next step includes passing the partially warmed nitrogen stream through at least one turboexpander that reduces the temperature and pressure of the partially warmed nitrogen stream to obtain a cold nitrogen stream. The turboexpander may be coupled to the first heat exchanger by any means known in the art. The turboexpander exhaust may flow to the first heat exchanger. The turboexpander may include a brake, such as a blower, fan, or oil pump, to circulate and cool and dissipate energy. The turboexpander may be coupled to a compressor to capture energy produced by the turboexpander.

By passing through one turboexpander, the warm nitrogen stream can be cooled from about 30 degrees to about 130 degrees, or from about 50 degrees to about 100 degrees, and/or at a pressure of about 2 bar to about 100 bar, 4 bar to about 60 bar. , or about 30 bar to about 50 bar. The temperature and pressure of the stream can be further reduced by passing the stream through a second turboexpander connected in series with the first turboexpander. The first turboexpander may be coupled to a second turboexpander.

As used herein, a "turboexpander" is a device that achieves a decrease in temperature by creating a decrease in pressure while at the same time being able to be removed or captured to assist in the required cooling process by performing work. refers to any device that is used to produce useful energy that can be used to generate energy, such as, but not limited to, inward radial flow devices typically used in cryogenic processing. Turbo expanders use the energy of expanded gas to generate mechanical energy through rotation. A turboexpander rotates at high speed and energy can then be transferred through a shaft to a compressor, which recovers energy by compressing another feed gas stream. This process pulls up the pressurized feed gas stream to the compressor, which allows useful energy to be supplied back to the system.

Optionally, the method includes passing a partially warmed nitrogen stream through at least one compressor and at least one turboexpander in any order and returning via a first heat exchanger or a second heat exchanger. obtaining a flow of cold nitrogen. This method involves passing a partially warmed nitrogen stream through two to five compressors and two to five turboexpanders, and returning the cold nitrogen stream via a first heat exchanger or a second heat exchanger. It may also include a step of obtaining. The method involves passing a partially warmed nitrogen stream through 2 to 5 compressors, 2 to 5 turboexpanders, and 2 to 5 coolers, with cold nitrogen returning via a first heat exchanger. The method may include a step of obtaining a flow. The same number of coolers as compressors may be used in the process. One or more of the turboexpanders may be connected to one compressor by a shaft.

As used herein, "chiller" refers to any water or air cooler known in the art that extracts heat from a system, such as a fin-fan unit, shell, or shell for cooling a process stream with outside air. Refers to an and-tube type unit, or a plate cooler that uses a water or brine system to cool a process stream from elevated temperatures to near ambient temperature. Passing the stream through the cooler can reduce the temperature of the stream from about 40°C to about 100°C.

When passing the cold nitrogen stream through the first heat exchanger, this creates a loop in the process of pre-cooling, and this is the second pass of the nitrogen stream through the first heat exchanger. This allows the same initially supplied nitrogen to be recycled and used countercurrently to cool the hydrogen or helium gas stream a second time in the first heat exchanger. The cold nitrogen stream may be passed through a valve before passing through the first heat exchanger a second time in the pre-cooling process. Turboexpanders have a limited range of pressure ratios (inlet pressure/outlet pressure), so if necessary, instead of adding a second turboexpander, for example, a valve can be added to the system to further reduce the pressure. You may let them. Therefore, when using a valve, there is a pressure drop in the nitrogen flow across the valve. The valve may reduce the temperature and pressure of the nitrogen stream and increase the proportion of gas in the nitrogen stream.

After passing through the second heat exchanger, the fully warmed nitrogen gas stream has a temperature of about 15°C to about 30°C, or about 20°C to about 28°C, and about 0.5 bar(a) to about 2 bar(a ), or from about 1 bar(a) to about 2 bar(a). The fully warmed nitrogen gas stream passes through another processing loop including at least one turboexpander and optionally at least one compressor for pressurization and cooling, and then to a second heat exchanger. May be reintroduced. The fully warmed nitrogen gas stream passes through another processing loop for pressurization and cooling, including at least one turboexpander and optionally at least one compressor, then a first heat exchanger and It may then be reintroduced into the second heat exchanger.

A pre-cooling system using liquid nitrogen for hydrogen or helium liquefaction is also disclosed. The system exchanges heat between a stream of warm hydrogen or helium gas; a stream of pressurized liquefied nitrogen from a source of liquefied nitrogen; a stream of pressurized liquefied nitrogen and a partially cooled hydrogen or helium gas stream; a first heat exchanger configured to increase the temperature of the pressurized liquefied nitrogen stream to obtain a partially warmed nitrogen gas stream and reduce the temperature of the partially cooled hydrogen or helium gas stream; at least one turboexpander configured to reduce the temperature of the heated nitrogen gas stream; exchanging heat between the partially heated nitrogen gas stream and the heated hydrogen or warm helium gas stream to produce the partially heated nitrogen gas; and a second heat exchanger configured to increase the temperature of the gas stream and decrease the temperature of the hot hydrogen or helium gas stream. The first heat exchanger or the second heat exchanger may be coupled to one turboexpander. The pre-cooling system may include a valve connected to one turboexpander. The valve may be configured to reduce the pressure of the nitrogen gas flow.

The precooling system includes at least one compressor and at least one cooler, and optionally at least one turboexpander configured to receive the fully warmed nitrogen gas flow after passing through the second heat exchanger. May include. The pre-cooling system may include at least one turboexpander configured to receive the warm nitrogen gas flow after passing through at least one compressor and at least one cooler. The precooling system includes 1 to 4 compressors, 1 to 4 coolers, and 1 to 4 compressors configured to receive the fully heated nitrogen gas flow after passing through a second heat exchanger. each compressor is connected to a cooler, and one to four turboexpanders are connected after the compressor and cooler in the system.

A pre-cooling system using liquid nitrogen for hydrogen or helium liquefaction is also disclosed, the system comprising: a stream of warm hydrogen or warm helium gas; a stream of pressurized liquefied nitrogen from a source of liquefied nitrogen; a stream of pressurized liquefied nitrogen. and a hot hydrogen or hot helium gas stream to increase the temperature of the pressurized liquefied nitrogen stream to obtain a warm nitrogen gas stream, and lower the temperature of the hot hydrogen or hot helium gas stream to precool it. a heat exchanger configured to obtain a heated hydrogen or helium gas stream; coupled to the heat exchanger and configured to reduce the temperature of a partially heated nitrogen gas stream discharged from the heat exchanger; at least one turboexpander. The precooling system includes at least one compressor and at least one cooler configured to receive the warm nitrogen gas flow after passing through the heat exchanger, and optionally at least one compressor and at least one cooler. It may also include at least one turboexpander configured to receive the warm nitrogen gas flow therethrough. The pre-cooling system may also include a valve coupled to the turboexpander configured to reduce the pressure of the nitrogen gas stream.

Systems and processes for precooling hydrogen or helium gas using a stream of liquid nitrogen are described herein. Particular embodiments of the present disclosure include those set forth in the following paragraphs described with reference to the figures. Although some configurations are described with specific reference to only one figure (e.g., FIGS. 1, 2, 3, 4, etc.), they are equally applicable to other figures and may be modified from other figures or the discussion above. May be used in combination with

1-4 illustrate non-limiting examples of various systems and processes 100, 200, 300, 400 for pre-cooling hydrogen or helium gas using a stream of liquid nitrogen in accordance with this disclosure. The liquid nitrogen stream (LIN) 104, 204, 304, 404 is supplied from any LIN supply system, such as one or more tankers, tanks, pipelines, etc., or any combination thereof. The system includes at least one heat exchanger, for example a first heat exchanger 131, 231, 331, 431 and a second heat exchanger 130, 230, 330, 430. These systems include pumps 132, 232, 332, 432 for receiving a liquid nitrogen stream and increasing the pressure to create a pressurized liquid nitrogen stream 105, 250, 306, 406. The pressurized liquid nitrogen stream may be split into more than one stream, eg, two streams 250, 240. Hot hydrogen or helium gas is supplied from any source in stream 101, 201, 301, 401, which is partially cooled via a second heat exchanger in hydrogen or helium gas stream 102, 202, 302, 402, which obtains a pre-cooled hydrogen or helium gas stream 103, 203, 303, 403 via a first heat exchanger for further cooling.

FIG. 1 shows a system 100 for precooling hydrogen or helium gas using a stream of liquid nitrogen. Liquid nitrogen flow 104 is directed through pump 132 to increase pressure. The pressurized liquid nitrogen stream 105 passes through a first heat exchanger 131 that transfers energy between the opposingly flowing partially cooled hydrogen or helium gas stream 102 and the pressurized liquid nitrogen stream 105, thereby Increase the temperature of the nitrogen stream. Partially warmed nitrogen gas stream 106 then passes through turboexpander 133 to obtain cold nitrogen gas stream 107 having a lower pressure and lower temperature than stream 106. It is envisioned that the system may include more than one turboexpander connected in series to reduce the temperature and pressure of the nitrogen stream before re-entering the first heat exchanger. The disclosure also provides that multiple turboexpanders, such as 2, 3, or 4 turboexpanders, may be connected in series at each specified location of the turboexpanders if further reduction in flow pressure is required. Good, including alternative embodiments.

The cold nitrogen gas stream 107 then completes the loop via the first heat exchanger, and on the second pass of the nitrogen gas stream through the first heat exchanger, the partially cooled hydrogen or helium gas stream 102 and a cold nitrogen stream 107 to obtain a partially warmed nitrogen gas stream 108 and a pre-cooled hydrogen or helium gas stream 103.

Partially warmed nitrogen gas stream 108 then passes through a second heat exchanger 130 where energy is transferred between hot hydrogen or warm helium gas stream 101 and partially warmed nitrogen gas stream 108 to achieve complete heating. A warm nitrogen gas stream 109 and a partially cooled hydrogen or helium gas stream 102 are obtained, which then passes through a first heat exchanger 131 .

The second heat exchanger 130 may include supplemental refrigeration, shown here as propene streams 114, 115. Liquid propene stream 114 passes through a second heat exchanger that exchanges heat between supplemental refrigeration and hot hydrogen or warm helium gas stream 101 and exits as gaseous propene stream 115. The second heat exchanger may include supplemental refrigeration coupled to the second heat exchanger. Supplemental refrigeration supplements the coolant for the pre-cooling process and may be supplied from any other known source of refrigeration. Supplemental refrigeration may be vapor compression refrigeration, absorption refrigeration, mixed refrigerant refrigeration, or any other means known to extract heat from hot hydrogen or helium gas streams. Auxiliary refrigeration may include one refrigeration stream or two refrigeration streams that may be the same or different. The supplemental refrigeration may be a propene refrigeration stream that provides a liquid stream at a temperature of about -20°C to -50°C and exits the system as a gas stream.

Having described embodiments of the disclosure, further aspects will now be described. FIG. 2 shows a system 200 for precooling hydrogen or helium gas using a stream of liquid nitrogen. In FIG. 2, liquid nitrogen is pumped to high pressure and after evaporation and superheating for hydrogen cooling, passes through a turbo expander and returns for further cooling of the hydrogen. A valve 235 is shown between flows 208 and 209 to meet the aerodynamic constraints of the turboexpander as needed. Supplemental refrigeration is provided as part of the refrigeration process, for example from propene vapor-compression refrigeration, at a temperature level significantly higher than that of liquid nitrogen.

In the system of FIG. 2, the divided pressurized liquid nitrogen streams 240, 250 pass through a first heat exchanger 231, which warms the divided pressurized liquid nitrogen streams 240, 250 and maintains a substantially constant pressure. For example, the pressure difference may be less than about 1 bar(a). Although it is envisioned that the streams may exit any desired outlet to achieve the desired heat exchange, each of the split partially warmed nitrogen streams 241, 251 exits the first heat exchanger at a different outlet. The separated partially warmed nitrogen streams 241 , 251 are then combined into a single partially warmed nitrogen stream 207 and passed to a turboexpander 233 connected to a brake 234 . As it passes through the turboexpander, one warm nitrogen stream 207 is cooled, the pressure is reduced, and the amount of liquid in the stream is also reduced, for example from about 0% in stream 207 to about 6% in stream 208. It increases to about 10%. A valve 235 is shown between the turbo expander 233 and the first heat exchanger 231, which cools the cold nitrogen stream 208 before returning to the first heat exchanger and passing through the first heat exchanger a second time. The temperature and pressure of nitrogen stream 208 is reduced. By passing through the first heat exchanger 231, the cold, low pressure nitrogen stream 209 is warmed. Upon passing through the first heat exchanger 231, the liquid in the cold, low pressure nitrogen stream 209 is vaporized such that the partially warmed nitrogen gas stream 210 is approximately 0% liquid. The partially warmed nitrogen gas stream is then directed through a second heat exchanger 230 where the partially warmed nitrogen gas stream 210 is heated and the warm hydrogen or warm helium gas stream 201 is cooled to completely warm nitrogen. A gas stream 211 and a partially cooled hydrogen or helium gas stream 202 are obtained. It can be seen from the figure that the partially warmed nitrogen gas stream 210 exits the first heat exchanger 231 and then enters the second heat exchanger 230, although the first and second heat exchangers are In the case of two parts of one unit, it can be understood that the flow flows directly from the first heat exchanger to the second heat exchanger while remaining within one heat exchanger unit. The second heat exchanger 230 may include supplemental refrigeration, such as propene streams 214, 215. The liquid propene stream 214 passes through a second heat exchanger 230 that exchanges heat between the auxiliary refrigeration and the hot hydrogen or hot helium gas stream 201, such that the liquid propene stream 214 passes through the second heat exchanger to the gas propene. It comes out as stream 215. Table 2 includes a list of the streams and equipment shown in FIG. 2, as well as the characteristics of each of the streams. The liquid nitrogen consumption calculated by dividing the LIN feed flow rate by the pre-cooled hydrogen flow rate (ie, the flow rate of streams 204/203) is 5.18 kg LIN/kg LH ₂ .

Figure 3 shows a process and system for precooling hydrogen or helium gas using a liquid nitrogen stream and four turboexpander-compressors and auxiliary refrigeration supplied at -26°C to -46°C. 300 is shown. The system of FIG. 3 is configured such that liquid nitrogen stream 304 is diverted and a portion of the liquid nitrogen supply is routed through pump 332 to obtain pressurized liquid nitrogen stream 306. Another portion of the liquid nitrogen supply 305 passes through valve 384 and stream 325 then enters a first heat exchanger 331 where it is warmed to obtain a first partially warmed nitrogen gas stream 326 and then This is passed through a second heat exchanger for further warming to obtain a first fully warmed nitrogen gas stream 327. A stream of pressurized liquid nitrogen 306 also passes through a first heat exchanger 331, whereby the temperature of the stream of pressurized liquid nitrogen 306 increases and the pressure remains substantially constant, for example with a pressure difference of about 1 bar (a ) may be less than The second partially warmed nitrogen gas stream 322 then passes through a second heat exchanger 330 for further warming and exits through a central outlet to obtain a nitrogen gas stream 307, each of which is sent to a compressor 335, 336. Nitrogen gas streams 308, 309 are obtained through coupled turboexpanders 333, 334. The turboexpander may be designed to drive a compressor, pump, hydraulic brake, or any other similar power consuming device that extracts energy from the system 300. Upon passing through the first turboexpander 333 , the nitrogen gas stream 307 is cooled to a cold nitrogen gas stream 308 . Upon passing through the second turboexpander 334, the cold nitrogen gas stream 308 is cooled to a cold, low pressure nitrogen gas stream 309. Each turboexpander reduces the pressure of the nitrogen flow through it. optionally a second turboexpander to reduce the temperature and pressure of the low temperature, low pressure nitrogen stream before it returns to the first heat exchanger and passes through the first heat exchanger a second time; There may be a valve (not shown) between the heat exchanger and the first heat exchanger. After passing through the first heat exchanger 331, the third partially warmed nitrogen gas stream 310 then passes through the second heat exchanger 330, where the third partially warmed nitrogen gas stream 310 is heated. Warm hydrogen gas stream 301 is cooled to provide a fully warmed nitrogen gas stream 311 and a partially cooled hydrogen gas stream 302. The second heat exchanger 330 has two auxiliary refrigeration systems as shown, including a first auxiliary refrigeration system comprising propene streams 350, 351 and a second auxiliary refrigeration system comprising propene streams 360, 361. Supplemental refrigeration may also be included. In these supplemental refrigeration systems, the liquid propene stream 350, 360 passes through a second heat exchanger that exchanges heat between the propene stream and the hot hydrogen gas stream 301, such that the liquid propene stream 350, 360 has a second heat exchanger. It passes through the exchanger and exits as gas propene streams 351, 361.

In FIG. 3, a fully warmed nitrogen gas stream 311 passes through four sets of compressors 335, 336, 337, 338 followed by coolers 382, 383, 381, 380, and then a third and fourth turbo-expander. 339 and 340. It is envisioned that any number of compressor and cooler sets (eg, 1 to 6) followed by any number of turboexpanders (eg, 1 to 4) may be incorporated into the system. The compressor and subsequent cooler remove the heat of compression with outside air or with cooling water or brine. Nitrogen stream 311 passes through a compressor, nitrogen stream 312 passes through a condenser, nitrogen stream 313 passes through a compressor, nitrogen stream 314 passes through a condenser, nitrogen stream 315 passes through a compressor, After nitrogen stream 316 passes through a cooler, nitrogen stream 317 passes through a compressor, nitrogen stream 318 passes through a cooler, and nitrogen streams 319, 320 pass through a turboexpander, nitrogen gas stream 321 is 2 heat exchanger 330, fully warmed nitrogen gas stream 323 is combined with fully warmed nitrogen gas stream 327 to obtain a combined fully warmed nitrogen gas stream 324.

Table 3 includes a list of the streams and equipment shown in FIG. 3, as well as the characteristics of each of the streams. The liquid nitrogen consumption calculated by dividing the LIN feed flow rate by the pre-cooled hydrogen flow rate is 4.30 kg LIN/kg LH ₂ .

FIG. 4 shows a process and system 400 for precooling hydrogen or helium gas using a stream of liquid nitrogen, where the system includes two turboexpander-compressor sets for precooling without the use of an auxiliary refrigeration unit. including combinations of The system of FIG. 4 is configured such that the liquid nitrogen supply is split into two streams, with a first portion of the liquid nitrogen supply passing through pump 432 to obtain pressurized liquid nitrogen stream 406. Another portion of the liquid nitrogen supply 405 passes through a first heat exchanger 431 where it is warmed and vaporized to obtain a first partially warmed nitrogen gas stream 421 which is then used for further warming. A first fully warmed nitrogen gas stream 422 is obtained through a second heat exchanger. The pressurized liquid nitrogen stream 406 is split into two pressurized liquid nitrogen streams 409, 407, each passing through a first heat exchanger 431 and exiting from a different outlet, thereby increasing the temperature of the pressurized liquid nitrogen stream. The pressure remains substantially constant, eg, the pressure difference is less than about 1 bar(a), and then joins the second partially warmed nitrogen gas stream 411. The second partially warmed nitrogen gas stream 411 then passes through a second heat exchanger 430 for further warming to obtain a fully warmed nitrogen gas stream 412. In this example, the fully warmed nitrogen gas stream 412 passes through two sets of compressors 434, 436 followed by coolers 481, 480, followed by turboexpanders 435, 433, each of which , 436. It is envisioned that any number of compressor and cooler pairs (eg, 1 to 6) followed by any number of turboexpanders (eg, 1 to 4) may be incorporated into the system. Stream 412 goes through the compressor, stream 413 goes through the cooler, stream 414 goes through the compressor, stream 415 goes through the cooler, stream 416 goes through the turbo expander, and stream 417 goes through the turbo expander. After passing through the expander, the low temperature, low pressure nitrogen gas stream 418 passes through a first heat exchanger 431 to obtain another partially warmed nitrogen gas stream 419, and then passes through a second heat exchanger 430 to obtain a completely heated nitrogen gas stream 419. A warmed nitrogen gas stream 420 is obtained which is combined with stream 422 to obtain a combined complete warmed nitrogen gas stream 423.

Table 4 includes a list of the streams and devices shown in FIG. 4, as well as the characteristics of each of the streams. The liquid nitrogen consumption calculated by dividing the LIN feed flow rate by the pre-cooled hydrogen flow rate is 5.35 kg LIN/kg LH ₂ .

A conventional pre-cooling process is shown in FIG. 5 and described above. Table 5 includes a list of the streams and devices shown in FIG. 5, as well as the characteristics of each of the streams. By dividing the flow rate of liquid nitrogen stream 504 by the flow rate of pre-cooled hydrogen stream 503, the liquid nitrogen requirement is 7.28 kg of liquid nitrogen per kg of hydrogen supply (7.28 kg LIN/kg LH ₂ ), where hydrogen is also subjected to ortho-para transformation.

While this disclosure has described what are considered to be various aspects and certain preferred embodiments of this disclosure, those skilled in the art will be able to make changes and modifications thereto without departing from the spirit of this disclosure. It will be appreciated that the present disclosure is intended to include all such changes and modifications as fall within the true scope of this disclosure.

Claims (30)

A method for precooling hydrogen or helium gas using a stream of liquid nitrogen, the method comprising:
a. providing a pressurized liquid nitrogen stream containing liquid nitrogen at a pressure of about 15 bar(a) to about 70 bar(a);
b. passing the pressurized liquid nitrogen stream and the partially cooled hydrogen or helium gas stream through a first heat exchanger that exchanges heat between the pressurized liquid nitrogen stream and the partially cooled hydrogen or helium gas stream; obtaining a first partially warmed nitrogen stream and a pre-cooled hydrogen or helium gas stream;
c. passing the first partially warmed nitrogen stream through one or more turboexpanders that reduce the temperature and pressure of the partially warmed nitrogen stream to obtain a cold nitrogen stream;
d. passing the cold nitrogen stream through the first heat exchanger and second heat exchanger to obtain the pre-cooled hydrogen or helium gas stream and a fully warmed nitrogen gas stream. Step (d) comprises passing the cold nitrogen stream through the first heat exchanger that exchanges heat between the cold nitrogen stream and the partially cooled hydrogen or helium gas stream. obtaining a gas stream and said pre-cooled hydrogen or helium gas stream; , through the second partially warmed nitrogen gas stream to obtain a fully warmed nitrogen gas stream and the partially cooled hydrogen or helium gas stream. 3. The method of claim 2, wherein the first heat exchanger and the second heat exchanger are separate devices. 2. The method of claim 1, wherein the first heat exchanger and the second heat exchanger are parts within one heat exchanger. 5. A method according to any preceding claim, wherein the pressurized liquid nitrogen has a pressure of about 15 bar(a) to about 70 bar(a). 5. A method according to any preceding claim, wherein the pressurized liquid nitrogen has a pressure of about 20 bar(a) to about 55 bar(a). step (a) providing a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a); and subsequently increasing the pressure of the liquid nitrogen stream to obtain the pressurized liquid nitrogen stream. 7. The method according to any one of claims 1 to 6, comprising: step (a) providing a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a); and increasing the pressure of the first portion of the liquid nitrogen stream to obtain the pressurized liquid nitrogen stream. Method. 9. The method of claim 8, further comprising passing the second portion of the liquid nitrogen stream through the first heat exchanger to obtain a third partially warmed nitrogen stream. 10. The method of claim 9, further comprising directing the third partially warmed nitrogen stream through the second heat exchanger to obtain a second fully warmed nitrogen gas stream. 11. The method of any one of claims 1 to 10, further comprising utilizing an auxiliary refrigeration system coupled to the second heat exchanger. The pressurized liquid nitrogen stream is divided into a first pressurized liquid nitrogen stream and a second pressurized liquid nitrogen stream, and the first pressurized liquid nitrogen stream and the second pressurized liquid nitrogen stream are divided into the first heat exchanger. 3. The method of claim 2, wherein streams of pressurized liquid nitrogen are passed separately to exchange heat between the first and second streams of pressurized liquid nitrogen and the partially cooled hydrogen or helium gas stream. 13. A method according to any preceding claim, wherein step (c) comprises passing the first partially warmed nitrogen stream through one or two turboexpanders. 13. Any of claims 1 to 12, wherein step (c) comprises passing the first partially warmed nitrogen stream through one or more compressors before passing it through the one or more turboexpanders. The method described in paragraph 1. 15. The method of any one of claims 12 to 14, further comprising utilizing an auxiliary refrigeration system coupled to the second heat exchanger. A method for precooling hydrogen or helium gas using a stream of liquid nitrogen, the method comprising:
a. providing a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a);
b. directing a first portion of the liquid nitrogen stream to a first heat exchanger to obtain a first partially warmed nitrogen stream;
c. directing the first partially warmed nitrogen stream to a second heat exchanger to obtain a first fully warmed nitrogen gas stream;
d. increasing the pressure of the second portion of the liquid nitrogen stream to obtain a pressurized liquid nitrogen stream at a pressure of about 15 bar(a) to about 70 bar(a);
e. passing the pressurized liquid nitrogen stream and partially cooled hydrogen or helium gas stream in opposing directions through the first heat exchanger to generate a second partially warmed nitrogen gas stream and precooled hydrogen or helium gas stream; Steps to obtain;
f. A second fully heated nitrogen gas stream is passed through the second heat exchanger that exchanges heat between the second partially warmed nitrogen gas stream and a warm hydrogen or warm helium gas stream. obtaining a heated nitrogen gas stream and said partially cooled hydrogen or helium gas stream;
g. passing the second fully warmed nitrogen gas stream through one or more turboexpanders that reduce the temperature and pressure of the second fully warmed nitrogen gas stream to obtain a cold nitrogen stream;
h. The third partially warmed nitrogen gas stream and the pre-cooled nitrogen gas stream are passed through the first heat exchanger that exchanges heat between the cold nitrogen stream and the partially cooled hydrogen or helium gas stream. obtaining a hydrogen or helium gas stream;
i. A third fully heated nitrogen gas stream is passed through the second heat exchanger that exchanges heat between the third partially warmed nitrogen gas stream and a warm hydrogen or warm helium gas stream. obtaining a heated nitrogen gas stream and said partially cooled hydrogen or helium gas stream. before step (g) passing said second fully warmed nitrogen stream through one or more turboexpanders, passing said second fully warmed nitrogen stream through one or more compressors and one or more 17. The method of claim 16, including passing through a cooler. 17. The method of claim 16, wherein step (g) comprises passing the second fully warmed nitrogen stream through two turboexpanders connected in series. The pressurized liquid nitrogen stream is divided into a first pressurized liquid nitrogen stream and a second pressurized liquid nitrogen stream; the first pressurized liquid nitrogen stream and the second pressurized liquid nitrogen stream are separated from the pressurized liquid nitrogen stream. 19. The method according to any one of claims 16 to 18, wherein the heat exchanger is passed through one heat exchanger separately. 20. A method according to any one of claims 16 to 19, wherein the first heat exchanger and the second heat exchanger are separate devices. 20. A method according to any one of claims 16 to 19, wherein the first heat exchanger and the second heat exchanger are parts within one heat exchanger. 22. The method of any one of claims 16 to 21, further comprising utilizing an auxiliary refrigeration system coupled to the second heat exchanger. A method further comprising a system for recooling the second or third fully warmed nitrogen gas stream, the system for recooling comprising:
i. passing said second or third fully warmed nitrogen gas stream through a first compressor and a first cooler to obtain a compressed and cooled nitrogen gas stream, said first compressor is coupled to the second heat exchanger and the first cooler;
ii. passing the compressed and cooled nitrogen gas stream through one or more turboexpanders;
iii. passing the turbo-expanded nitrogen gas stream through the second heat exchanger to obtain a fourth fully warmed nitrogen gas stream. 24. The method of claim 23, wherein step (ii) comprises passing the compressed and cooled nitrogen gas stream through two turboexpanders connected in series. A pre-cooling system using liquid nitrogen for hydrogen or helium liquefaction, the system comprising:
a stream of hot hydrogen or helium gas;
a pressurized liquefied nitrogen stream from a source of liquefied nitrogen;
heat exchange between the pressurized liquefied nitrogen stream and a warm hydrogen or warm helium gas stream to increase the temperature of the pressurized liquefied nitrogen stream to obtain a warm nitrogen gas stream; a heat exchanger configured to reduce the temperature of the stream to obtain a pre-cooled nitrogen gas stream;
and at least one turboexpander coupled to the heat exchanger and configured to reduce the temperature of a partially warmed nitrogen gas stream discharged from the heat exchanger. 26. The precooling system of claim 25, further comprising at least one compressor and at least one cooler configured to receive the warm nitrogen gas stream discharged from the heat exchanger. 27. The precooling system of claim 26, further comprising at least one turboexpander configured to receive the warm nitrogen gas flow after passing through the at least one compressor and the at least one cooler. 26. The precooling system of claim 25, further comprising a valve coupled to the turboexpander configured to reduce the pressure of the nitrogen gas stream. A pre-cooling system using liquid nitrogen for hydrogen or helium liquefaction, comprising:
a stream of hot hydrogen or helium gas;
a pressurized liquefied nitrogen stream from a source of liquefied nitrogen;
exchanging heat between the pressurized liquefied nitrogen stream and a partially cooled hydrogen or helium gas stream to increase the temperature of the pressurized liquefied nitrogen stream to obtain a partially warmed nitrogen gas stream; a first heat exchanger configured to reduce the temperature of the hydrogen or helium gas stream;
at least one turboexpander configured to reduce the temperature of the partially heated nitrogen gas stream;
exchanging heat between the partially warmed nitrogen gas stream and the warmed hydrogen or warm helium gas stream to increase the temperature of the partially warmed nitrogen gas stream to obtain a fully warmed nitrogen gas stream; a second heat exchanger configured to reduce the temperature of the hydrogen or hot helium gas stream. 30. The precooling system of claim 29, further comprising at least one compressor and at least one cooler configured to receive the fully warmed nitrogen gas stream after passing through the second heat exchanger.