HEAT EXCHANGER AND/OR HEAT EXCHANGER-REACTOR INCLUDING CHANNELS HAVING THIN WALLS BETWEEN ONE ANOTHER

Abstract

The invention relates to a heat exchanger-reactor or heat exchanger including at least three stages with on each stage at least one area of millimetric channels that promote the exchange of heat and at least one distribution area upstream and/or downstream of the area of millimetric channels. The invention is characterized in that: said heat exchanger-reactor or heat exchanger is a component devoid of assembly interfaces between the various stages; and the channels in the area of millimetric channels are separated by walls less than 3 mm thick.

Claims

1-8. (canceled)

9. An exchanger-reactor comprising at least first, second, and third stages with, on each stage, at least one millimeter-scale channels zone encouraging exchanges of heat and at least one distribution zone upstream and/or downstream of the millimeter-scale channels zone, wherein: said exchanger-reactor or exchanger is a component that has no assembly interfaces between the various stages, and the channels of the millimeter-scale channels zone are separated by walls of a thickness less than 3 mm; said exchanger-reactor is a catalytic exchanger-reactor; the first stage comprises at least a distribution zone and at least a millimeter-scale channels zone adapted and configured for circulating a gaseous stream at a temperature at least greater than 700 C. so that the circulated gaseous stream supplies some of the heat necessary for the catalytic reaction; the second stage comprises at least a distribution zone and at least a millimeter-scale channels zone for circulating a gaseous stream reagent in a lengthwise direction of the millimeter-scale channels covered with catalyst in order to cause the gaseous stream to react and produce a gaseous product stream; the third stage comprises at least a distribution zone and at least a millimeter-scale channels zone for circulating the gaseous product stream produced on the second plate so that the circulated gaseous product stream supplies some of the heat necessary for the catalytic reaction; and on the second and the third stages, a system adapted and configured to circulate the gaseous product stream from the second stage to the third stage.

10. The exchanger-reactor of claim 9, wherein the channels of the millimeter-scale channels zone are separated by walls of a thickness less than 2 mm.

11. The exchanger-reactor of claim 9, wherein the channels of the millimeter-scale channels zone are separated by walls of a thickness less than 1.5 mm.

12. The exchanger-reactor of claim 9, wherein the cross sections of the millimeter-scale channels are circular in shape.

13. The use of an additive manufacturing method for the manufacture of the exchanger-reactor of claim 9.

14. The use of claim 13, wherein the additive manufacturing method uses, as base material, at least one micrometer-scale metallic powder.

15. The use of claim 13, wherein the additive manufacturing method is used for the manufacture of the connectors of the exchanger-reactor.

16. The use of claim 13, wherein the additive manufacturing method uses as energy source at least one laser.

17. A method of producing syngas employing the exchanger-reactor of claim 9.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0057] FIG. 1 illustrates various dimensions of etched plates to be defined in order to obtain the desired mechanical integrity.

[0058] FIG. 2 illustrates the steps performed during the manufacture of millistructured reactor-exchangers and/or exchangers.

[0059] FIG. 3 is a photo micrograph of a cross-section of a millistructured exchanger or reactor-exchanger including a semicircular channel made by a chemical etching technique.

[0060] FIG. 4 is a photo micrograph of a cross-section of a millistructured exchanger or reactor-exchanger including cylindrical channels made by an additive manufacturing technique.

DETAILED DESCRIPTION OF THE INVENTION

[0061] As a preference, the additive manufacturing method uses: [0062] as base material, at least one micrometer-scale metallic powder, and/or [0063] at least a laser as an energy source.

[0064] Specifically, the additive manufacturing method may employ micrometer-scale metallic powders which are melted by one or more lasers in order to manufacture finished items of complex three-dimensional shapes. The item is built up layer by layer, the layers are of the order of 50 m, according to the precision for the desired shapes and the desired deposition rate. The metal that is to be melted may be supplied either as a bed of powder or by a spray nozzle. The lasers used for locally melting the powder are either YAG, fiber or CO.sub.2 lasers and the melting of the powders is performed under an inert gas (argon, helium, etc.). The present invention is not confined to a single additive manufacturing technique but applies to all known techniques.

[0065] Unlike the traditional machining or chemical etching techniques, the additive manufacturing method makes it possible to create channels of cylindrical cross section which offer the following advantages (FIG. 4):

[0066] (i)better ability to withstand pressure and thus allow a significant reduction in channel wall thickness, and

[0067] (ii)of allowing the use of pressure equipment design rules that do not require a burst test to be carried out in order to prove the effectiveness of the design as is required by section VIII div.1 appendix 13.9 of the ASME code.

[0068] Specifically, the design of an exchanger or of a reactor-exchanger produced by additive manufacturing, making it possible to create channels of cylindrical cross section, relies on the usual pressure equipment design rules that apply to the dimensioning of the channels, distributors and collectors of cylindrical cross sections that make up the millistructured reactor-exchanger or exchanger.

[0069] By way of example, the sizing of the wall of straight channels of rectangular cross section (value t3 in FIG. 1) of an exchanger-reactor made of nickel alloy (HR 120), dimensioned in accordance with ASME (American Society of Mechanical Engineers) section VIII div. 1 appendix 13.9, is 1.2 mm. By using channels of cylindrical cross section, this wall thickness value as calculated by ASME section VIII div. 1 is then just 0.3 mm, representing a fourfold reduction in the wall thickness needed to withstand the pressure.

[0070] The reduction in the volume of material associated with this saving makes it possible (i) either to reduce the overall size of the apparatus for the same production capability given that the number of channels needed to achieve the target production capability is lower and thus occupies less space, (ii) or to increase the production capability of the apparatus while maintaining the overall size thereof, thereby allowing more channels to be included and thus a larger throughput of reagents to be treated. For example, the reduction in wall thickness allowed by the change in shape of the channels offered by additive manufacturing makes it possible to reduce by 30% the overall volume of an exchanger-reactor that offers the same hydrogen production capability as an exchanger-reactor manufactured by the assembly of chemically machined plates.

[0071] In addition, in the case of a milli-structured exchanger-reactor or exchanger produced from a noble alloy with a high nickel content, the necessary reduction of material tends toward an eco design that is beneficial to the environment while at the same time reducing the cost of raw materials.

[0072] Additive manufacturing techniques ultimately make it possible to obtain items said to be solid which unlike assembly techniques such as diffusion brazing or diffusion bonding, have no assembly interfaces between each etched plate. This property goes towards improving the mechanical integrity of the apparatus by eliminating, by construction, the presence of lines of weakness and by thereby eliminating a source of potential failure.

[0073] Obtaining solid components by additive manufacture and eliminating diffusion brazing or diffusion bonding interfaces makes it possible to consider numerous design possibilities without being confined to wall geometries designed to limit the impact of potential assembly defects such as discontinuities in the brazed joints or in the diffusion-bonded interfaces.

[0074] Additive manufacture makes it possible to create shapes that are inconceivable using traditional manufacturing methods and thus the manufacture of the connectors for the millistructured reactor-exchangers or exchangers can be done in continuity with the manufacture of the body of the apparatus. This then makes it possible not to have to perform the operation of welding the connectors to the body, thereby making it possible to eliminate a source of impairment to the structural integrity of the equipment.

[0075] Control over the geometry of the channels using additive manufacture allows the creation of channels of circular cross section which, aside from the good pressure integrity that this shape brings with it, also makes it possible to have a channel shape that is optimal for the deposition of protective coatings and catalytic coatings which are thus uniform along the entire length of the channels.

[0076] By using this additive manufacturing technology, the gain in productivity aspect is also permitted through the reduction in the number of manufacturing steps. Specifically, the steps of creating a reactor using additive manufacture drop from seven to four (FIG. 5). The critical steps, those that may cause the complete apparatus or the plates that make up the reactor to be scrapped, of which there were four when using the conventional manufacturing technique by assembling chemically etched plates, drop to two with the adoption of additive manufacture. Thus, the only steps to remain are the additive manufacturing step and the step of applying coatings and catalysts.

[0077] By way of example, a reactor-exchanger according to the invention can be used for the production of syngas. Further, an exchanger according to the invention can be used in an oxy-combustion process for preheating oxygen.

[0078] In the context of hydrogen production of less than 5 Nm.sup.3/h, let us consider the example of an exchanger-reactor having the following dimensional properties: [0079] nickel-based materials (Inconel 601-625-617-690) [0080] channels 2 mm in diameter for the reagent and return channels [0081] channels 1 mm in diameter for the heat supply channels [0082] wall thickness 0.4 mm [0083] effective length of channels 288 mm [0084] number of reagent channels 432 [0085] number of return channels 216 [0086] number of heat supply channels 918 [0087] width of exchanger-reactor 66 mm [0088] overall length of exchanger-reactor 350 mm [0089] height of exchanger-reactor 95 mm [0090] the reagent channels and the return channels are coated with a protection against corrosion [0091] the reagent channels are coated with catalyst
From the following input conditions:

TABLE-US-00001 Reagent gas Heat transfer fluid Flow rate Nm.sup.3/h 7.70 43 Temperature C. 519.22 822.18 Pressure bar 11 11 Composition CH.sub.4 0.19 0 H.sub.2O 0.62 0 CO.sub.2 0.04 0 H.sub.2 0.14 0 CO 0.0015 0 N.sub.2 0.0000 1
The above described equipment allows the following performance to be achieved:

TABLE-US-00002 Gas produced Flue gases Flow rate Nm.sup.3/h 10.24 43 Temperature C. 585.15 610.8 Pressure bar 11 11 Composition CH.sub.4 0.02 0 (mol basis) H.sub.2O 0.31 0 CO.sub.2 0.06 0 H.sub.2 0.51 0 CO 0.1 0 N.sub.2 0.0000 1 Pressure drop mbar 1.05 122
For an equivalent component exhibiting the same properties as the example and manufactured according to conventional techniques of chemical machining and assembly by brazing or by diffusion welding, the component dimensions imposed notably by mechanical strength constraints would be 350 mm126 mm84 mm. The total volume of the component produced by additive manufacturing is therefore considerably reduced in comparison with the equivalent exchanger-reactor produced using conventional manufacturing methods.

[0092] While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.

[0093] The singular forms a, an and the include plural referents, unless the context clearly dictates otherwise.

[0094] Comprising in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing i.e. anything else may be additionally included and remain within the scope of comprising. Comprising is defined herein as necessarily encompassing the more limited transitional terms consisting essentially of and consisting of; comprising may therefore be replaced by consisting essentially of or consisting of and remain within the expressly defined scope of comprising.

[0095] Providing in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.

[0096] Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.

[0097] Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.

[0098] All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.