FR3015651A1 - METHOD AND APPARATUS FOR HEATING A FLUID - Google Patents

Abstract

In a fluid heating process, fluid is heated by heat exchange with at least one member (G, G ', E) for heating comprising at least one element with magnetocaloric properties (G, G') integrated in a suitable circuit to drive a magnetic flux. The element is in alternating thermal contact with a cold source constituted by the fluid to be heated (3) and a hot source (11, 11A) and the variation of the magnetic flux by the magnetocaloric effect generates energy. electrical and / or mechanical.

Description

The present invention relates to a method and apparatus for heating a cryogenic fluid to provide a heated gas. A cryogenic fluid is a fluid that is at a temperature below 20 ° C, or even -55 ° C, or even -100 ° C. A cryogenic liquid is a liquid which is in liquid form at a temperature below -20 ° C, or even at -55 ° C or at -100 ° C. The invention relates more particularly to a method for producing gas under pressure at a predetermined temperature and a pressure determined from a liquefied gas tank stored at cryogenic temperature, in which liquefied gas is extracted from the tank and is then heated by exchange. thermal device with at least one heating element. The invention particularly relates to a method or an installation for producing and distributing gas, especially compressed gas, from at least one cryogenic tank containing liquefied gas. The invention may more particularly relate to a method or facility for supplying gas at non-cryogenic temperatures (i.e., -80 ° C to room temperature) from cryogenic tanks. Industrial users requiring relatively large amounts of gas generally produce their gas from cryogenic storage. Indeed, cryogenic tanks can store relatively large quantities of gas. Air gases such as nitrogen, oxygen, and argon have a cryogenic storage temperature of between 80K and 110K and therefore have a high densification capacity in the liquid state. The cryogenic tank supplies a gas supply installation at specified non-cryogenic temperatures (for example between -40 ° C. and 20 ° C.) and at determined pressures. Depending on the applications, the gas can thus be produced at a pressure close to atmospheric pressure or at higher pressure levels, for example between 100 and 800 bar, in particular between 200 and 500 bar. Thus, hydrogen stored in cryogenic form (for example at 20K) can provide typically very high pressure hydrogen (eg 500 to 800bar) to automotive vehicles running on fuel cells.

To do this, the gas stored at cryogenic temperatures is heated and vaporized by the user's installation, typically using atmospheric evaporators and heaters. These cryogenic storage systems make it possible to reduce the need for transport logistics and increase the autonomy of the consumers, but require a step of liquefaction and maintenance of the fluid at cryogenic temperatures which are expensive in the energy and economic balance of the installation. Magnetic refrigeration is based on the use of magnetic materials having a magnetocaloric effect. Reversible, this effect results in a variation of their temperature when they are subjected to the application of an external magnetic field. On the other hand, if the materials are subjected to a varying temperature, the magnetic conductivity of the materials varies. The optimal ranges of use of these materials are in the vicinity of their Curie temperature (Tc). It is known from Alves et al., "Simulation of a Thermomagnetic Motor using NiFe Alloy and Gd". , 5th International Conference on Ambient Temperature Refrigeration, 2012, converting heat into engine work and / or electricity by modifying a magnetic field created by a magnetocaloric effect material. The modification of the field makes it possible to create a motor work 20 makes it possible to create a motor work and / or an electric current. Examples of electric generators using a material having a magnetocaloric effect using a cold source and a hot source are given in FR-A-2914503 and US-A-8453466. A magnetic refrigeration device employs magnetocaloric material elements that generate heat when magnetized and absorb heat when demagnetized. It can implement a magnetocaloric material regenerator to amplify the temperature difference between the "hot source" and the "cold source": it is called active magnetic refrigeration recovery. A heat pump is a thermodynamic device for transferring a quantity of heat from a medium considered as "transmitter" (supplying medium), said "cold" source to a "receiver" medium of calories, said "hot" source. The cold source is the medium from which the heat is extracted and the hot source the medium where it is reinjected, the cold source being at a colder temperature than the hot source.

An ambient temperature is the temperature of the ambient air in which the process is located, or a temperature of a cooling water circuit related to the air temperature. A subambient temperature is at least 10 ° C below room temperature. A cryogenic temperature is below -20 ° C, or even -55 ° C, or even 100 ° C. An object of the present invention is to overcome all or part of the disadvantages of the prior art noted above.

It is an object of the present invention to promote the cold generated by the vaporization and / or the heating of a cryogenic liquid, in particular the vaporization and / or the heating in an emergency vaporizer or the vaporization and / or the heating in a system for supplying gas from a cryogenic liquid storage.

It is often necessary to vaporize and / or heat a cryogenic liquid to provide gas. Usually the liberated frigories are transferred to the fluid that heats the liquid, which may be air, water or water vapor, and the frigories are then lost to the atmosphere. According to one object of the invention, there is provided a fluid heating process, or even a liquefied gas, up to a predetermined temperature, at a predetermined pressure in which fluid is heated, or even vaporized in the case of a liquid, by heat exchange with at least one heating element, characterized in that the at least one heating element comprises at least one element with magnetocaloric properties, integrated in a circuit capable of driving a magnetic flux, said at least one element being in contact thermal alternately with a cold source, constituted by the fluid to be heated, or even the liquid to be vaporized, and a hot source constituted by the ambient or another source hotter than the fluid to be heated and means for generating energy electrical and / or mechanical by varying the magnetic flux by the magnetocaloric effect.

According to other optional aspects: the fluid to be heated has at least one of the following fluids as main / main component: air, nitrogen, oxygen, argon, dioxide carbon, methane, helium, hydrogen, carbon monoxide. the fluid to be heated contains at least 40 mol% of one of the following fluids: air, nitrogen, oxygen, argon, carbon dioxide, methane, helium , hydrogen, carbon monoxide. the fluid to be heated contains at least 60 mol% of one of the following fluids: air, nitrogen, oxygen, argon, carbon dioxide, methane, helium , hydrogen, carbon monoxide. the fluid to be heated contains at least 75 mol% of one of the following fluids: air, nitrogen, oxygen, argon, carbon dioxide, methane, helium , hydrogen, carbon monoxide. the fluid comes from a fluid reservoir, stored at optionally cryogenic temperature. - The fluid from the reservoir is first compressed in a pump before being heated by means of the heating member. the fluid is a liquid. - The liquid is first preheated and then vaporized, then finally possibly reheated to a temperature close to room temperature. a first heating member serves to vaporize the liquid and a second heating member serves to heat the vaporized liquid and optionally a third heating member serves to preheat the liquid to be vaporized, at least one of the first, second and third members comprising least one element with magnetocaloric properties, integrated in a circuit capable of driving a magnetic flux. the fluid heated by the member is at a pressure below its critical pressure - the fluid heated by the member is at a pressure greater than its critical pressure - the fluid to be heated is put in direct contact with the element with properties magnetocaloric. the heat exchange of the heating is carried out through a heat exchanger with a coolant having been in contact with the magnetocaloric element. - The heat exchange is carried out through an intermediate heat transfer circuit with the coolant having been in contact with the element with magnetocaloric properties. - At least a portion of the fluid is heated and / or vaporized by means of a vaporizer independent of the heating member. According to another object of the invention, there is provided a method of liquefying a gas to produce a liquid and vaporizing the liquid in which the vaporization of the liquid is carried out according to one of the preceding claims if the price of electricity is above a threshold and the liquefaction of the gas takes place if the price of electricity is below the threshold, preferably by cooling the gas by magnetic refrigeration. According to another object of the invention, there is provided a fluid heating apparatus, or even liquefied gas, up to a predetermined temperature, at a predetermined pressure comprising means for allowing heat transfer between the fluid that is to be heated. , or even vaporized in the case of a liquid, and at least one heating element, characterized in that the at least one heating element comprises at least one element with magnetocaloric properties, integrated in a circuit capable of driving a magnetic flux, said at least one element being in thermal contact alternately with a cold source, constituted by the fluid to be heated, or even the liquid to be vaporized, and a hot source constituted by the ambient or another source hotter than the fluid to be heated and means for generating electrical and / or mechanical energy by varying the magnetic flux by the magnetocaloric effect. According to other objects of the invention: the apparatus comprises means for sending the liquefied gas to be heated to a vaporizer connected in series or in parallel with the heating member. the fluid is the only fluid that heats up by heat exchange with the heating member. the fluid is heated in an exchanger in which only one or more fluids reheated by the heating member (s) provide (s) calories. the apparatus does not include any element making it possible to produce the fluid to be heated at low temperature. the heat exchanger is disposed outside of any thermally insulated enclosure - the vaporizer is disposed outside any thermally insulated enclosure The invention may also relate to any alternative device or method comprising any combination of the above or above characteristics. below.

Other features and advantages will appear on reading the following description, with reference to the figures in which: - Figure 1 shows a schematic and partial view illustrating the structure and operation of a first example of installation of production of gas according to the invention, - Figures 2 and 3 show schematic and partial views illustrating the structure and operation of, respectively a second and a third examples of gas production plant according to the invention, - the figure 4 is a diagrammatic and partial view illustrating the structure and operation of a fourth example of a gas production installation according to the invention; FIGS. 5 and 6 show schematic and partial views illustrating the structure and operation of respectively a fifth and a sixth example of a gas production plant according to the invention.

FIG. 1 illustrates a first example of an installation for producing gas under pressure at a determined temperature Tf (for example 20 ° C.) and a determined pressure Pf (for example 7 bar) from a tank S of liquefied gas stored at cryogenic TO temperature (e.g. -175 ° C) and atmospheric pressure. The installation comprises a fluid withdrawal circuit of the reservoir S. This withdrawal circuit comprises a withdrawal line 1 of liquid connecting in series a discharge valve and a pump P. The withdrawal line is connected downstream of the pump P with two lines 3.5 in parallel. The pipe 3 is connected to a heat exchanger E with plates and fins and the pipe 5 is connected to a vaporizer V for heat exchange with the ambient air. The lines 3 and 5 meet downstream of the exchanger E and the vaporizer V in a common line 7. The gas at the pressure Pf determined and the determined temperature Tf can be supplied to the application. If vaporization is impossible in exchanger E because of a failure, the liquid can vaporize in the vaporizer by passing through line 5. A fluid 9 is heated by means of a heating member G which is connected a fluid 11 constituting a hot source. The fluid 11 may for example be ambient air or another fluid at a higher temperature than the fluid 3. The fluid 9 is sent to the heat exchanger E as the only fluid supplying calories. It serves to preheat, vaporize the fluid 3 to form a gas and to heat this gas. The fluid 9 thus cooled is sent to the heating member G. The member G comprises at least one element with magnetocaloric properties, integrated in a circuit capable of conducting a magnetic flux. The cooling resulting from the vaporization and / or heating of the fluid 3 modifies the magnetic flux and makes it possible to generate electrical and / or mechanical energy.

FIG. 2 illustrates an alternative embodiment which differs from the embodiment of FIG. 1 only in that line 5 is absent and the pipe is connected first to exchanger E and then to vaporizer V in series, so that the pipe 7 is the continuation of the pipe 3. Here, if the vaporization is not carried out or is not carried out entirely in the heat exchanger E, it can be carried out or terminated in the vaporizer V connected in series. FIG. 3 illustrates an alternative embodiment that differs from the embodiment of FIG. 1 in that the storage S is under pressure and that the pump P is absent. Figure 4 illustrates yet another variant of installation.

The installation of FIG. 4 differs from the installation of FIG. 1 in that the exchanger E is connected to two members G, G 'comprising at least one element with magnetocaloric properties, integrated in a circuit capable of driving a magnetic flux. A first member G 'has a hot source 11A and is connected to the exchanger E by means of a fluid 9A in order to vaporize the fluid 3 by means of a fluid 9A. The member G connected to the hot source 11 can provide heat sensitive to the fluid 3 by means of the fluid 9. It could be added a third member to preheat the liquid to vaporize 3. Alternatively one of the heating members could be a heater electric.

Another alternative would be to use one or two members G, G 'comprising at least one element with magnetocaloric properties, integrated in a circuit able to conduct a magnetic flux in the diagram of FIG. 2 and to terminate the heating or vaporization at means of a heat exchanger V with the ambient air.

Figure 5 illustrates yet another variant of a gas supply installation. The warming member G can be integrated in the exchanger E, so that the fluid 9 is not used to transfer the heat. Figure 6 illustrates yet another variant of 1 "installation of Figure 5 with the vaporizer V in series.

The facilities and methods described above allow gas to be produced from a cryogenic reserve while simultaneously producing electricity (or mechanical work) and heating, to heat and vaporize the gas to be dispensed at a temperature. higher than its cryogenic storage temperature. It may be envisaged to vaporize the liquid and generate mechanical and / or electrical energy only at certain periods, for example when the price of electricity exceeds a first threshold. It is possible to combine such a vaporization process with a liquefaction process which serves to liquefy gas which will then be vaporized in a process according to one of the figures already described. Thus the gas can be liquefied to store it when the price of electricity is below the first threshold, for example at night, and vaporized to produce electricity when the electricity is more expensive, for example during peaks of electricity. consumption.

Refrigeration for liquefaction is preferably performed by cooling the gas with magnetic refrigeration. Optionally the same member G; G 'provides at least a portion of the heat for vaporization and at least a portion of the refrigeration for liquefaction. For all the figures, the variation of the magnetic flux by the magnetocaloric effect in the element can generate electrical energy to be exported or used in the process. If not or in addition, the variation may generate mechanical energy to drive, for example, a rotating machine of the process or a generator.

Claims (16)

REVENDICATIONS1. Process for heating a fluid, or even a liquefied gas, up to a predetermined temperature (Tf), at a predetermined pressure in which fluid is heated, or even vaporized in the case of a liquid, by heat exchange with at least one member ( G, G ', E), characterized in that the at least one heating element comprises at least one element with magnetocaloric properties (G, G') integrated in a circuit capable of conducting a magnetic flux, the said at least one an element being in thermal contact alternately with a cold source, constituted by the fluid to be heated (3), or even the liquid to be vaporized, and a hot source (11, 11A) constituted by the ambient or another warmer source that the fluid to be heated and the variation of the magnetic flux by the magnetocaloric effect generates electrical and / or mechanical energy. 2. Method according to claim 1 wherein the fluid (3) has at least one of the following fluids as main / main component: air, nitrogen, oxygen, argon, carbon dioxide, methane, helium, hydrogen, carbon monoxide. 3. Method according to one of the preceding claims wherein the fluid (3) is derived from a fluid reservoir (S), stored at optionally cryogenic temperature. 4. Method according to claim 3 wherein the fluid (3) from the tank (S) is first compressed in a pump (P) before being heated by means of the heating member (G, G '). . 5. Method according to one of the preceding claims wherein the fluid (3) is a liquid. 6. The method of claim 5 wherein the liquid (3) is first preheated and then vaporized, then finally optionally reheated to a temperature close to room temperature. 7. The method of claim 6 wherein a first heating member (G, G ') is used to vaporize the liquid and a second member (G, G') for heating is used to heat the vaporized liquid and optionally a third heating member is used to preheat the liquid to be vaporized, at least one of the first, second and third members comprising at least one element with magnetocaloric properties, integrated in a circuit capable of conducting a magnetic flux. 8. Method according to one of the preceding claims wherein the fluid (3) heated by the member (G, G ', E) is at a pressure below its critical pressure 9. Method according to one of claims 1 to 7 wherein the fluid (3) heated by the member (G, G ', E) is at a pressure greater than its critical pressure 10. Method according to one of the preceding claims wherein the fluid to be heated (3) is brought into direct contact with the element with magnetocaloric properties (G, G '). 11. Method according to one of claims 1 to 9 wherein the heat exchange of the heating is carried out through a heat exchanger (E) with a coolant (9, 9A) having been in contact with the element with properties magnetocaloric (G, G '). 12. Method according to one of claims 1 to 9 wherein the heat exchange is carried out through an intermediate coolant circuit with the coolant having been in contact with the element magnetocaloric properties (G, G '). 13. Method according to one of the preceding claims wherein at least a portion of the fluid (1, 5) is heated and / or vaporized by means of a vaporizer (V) independent of the heating member (G, G '). , E). 14. A method of liquefying a gas to produce a liquid and vaporizing the liquid (1) in which the vaporization of the liquid is carried out according to one of the preceding claims if the price of electricity is above a threshold and the liquefaction of the gas is carried out if the price of the electricity is below the threshold, preferably by cooling or even liquefying the gas by magnetic refrigeration. 15. Apparatus for heating a fluid, or even a liquefied gas, up to a determined temperature (Tf), at a predetermined pressure, comprising means for allowing a transfer of heat between fluid (1, 3) which is to be heated or vaporized in the case of a liquid, and at least one member (G, G ', E) for heating, characterized in that the at least one heating element comprises at least one element with magnetocaloric properties (G, G'), integrated in a circuit capable of conducting a magnetic flux, said at least one element being in thermal contact alternately with a cold source, constituted by the fluid to be heated, or even the liquid to be vaporized, and a hot source (11, 11A) constituted by the ambient or another source hotter than the fluid to be heated and means for generating electrical and / or mechanical energy by varying the magnetic flux by the magnetocaloric effect. 16. Apparatus according to claim 15 comprising means for sending the liquefied gas to be heated to a vaporizer (V) connected in series or in parallel with the heating member (G, G ', E).