Manufacturing process for an exchanger-reactor or an exchanger by additive manufacturing

Abstract

The invention relates to a method for manufacturing a heat exchanger-reactor or an exchanger comprising a plurality of first stages and a plurality of stacked second stages, each stage being divided into a heat exchange zone and a distribution zone, said heat exchange zone and distribution zone respectively comprising a plurality of heat exchange channels intended to circulate a fluid, and a plurality of distribution channels fluidically connected with said plurality of heat exchange channels and intended to distribute the fluid in the heat exchange zone or to evacuate the fluid from said heat exchange zone, said method comprising a step of manufacturing the distribution zone carried out with a powder bed additive manufacturing method, and a step of manufacturing the heat exchange zone carried out with a concentrated energy deposition additive manufacturing method. Abstract figure: Fig. 1

Description

Title of the invention: Method for manufacturing an exchanger-reactor or an exchanger by additive manufacturing

[0001] The present invention relates to a method of manufacturing an exchanger-reactor or an exchanger, more particularly a milli-structured exchanger-reactor or a milli-structured exchanger, the manufacturing method comprising steps carried out by additive manufacturing.

[0002] In particular, the invention can be applied to an exchanger-reactor intended for the implementation of endothermic or exothermic catalytic reactions. The invention can find applications in several processes. It can be used in particular as an exchanger-reactor in reactions of the reforming type of hydrocarbons such as methane for the production of synthesis gas comprising hydrogen, or as an exchanger in oxycombustion processes for preheating oxygen. The invention can also be applied to a catalytic exchanger-reactor which liquefies a flow of gaseous hydrogen against a flow of refrigerant fluid such as liquid nitrogen.

[0003] A method for manufacturing a milli-structured heat exchanger-reactor using an additive manufacturing method is known from the prior art. Document FR3032783A1 defines a milli-structured heat exchanger-reactor as a chemical reactor where the exchanges of matter and heat are intensified by means of a channel geometry whose characteristic dimensions, such as the hydraulic diameter, are of the order of a millimeter. The channels constituting the geometry of these milli-structured exchangers-reactors are generally etched on plates assembled together, each of which constitutes a stage of the apparatus. The multiple channels that make up a single plate are generally linked to each other and passages are arranged to allow the transfer of the fluid used (gaseous or liquid phase) from one plate to another.Milli-structured exchanger-reactors are supplied with reactants by a distributor or a distribution zone, one of the roles of which is to ensure a homogeneous distribution of the reactants in all the channels. Document FR3032783A1 also discloses the details of a manufacturing process for such an exchanger-reactor. This process consists first of supplying powders of the desired material, then of producing a reactor and fluid connectors by additive manufacturing by means of layer-by-layer fusion of the powder.

[0004] Document FR3064348A1 discloses an exchanger-reactor comprising at least two fluid distribution zones, two fluid collection zones, two fluid connectors attached to the distribution and collection areas, an inlet, an outlet and an exchange area allowing heat transfer between the channels of the first fluid and second fluid. This exchanger-reactor is manufactured in a single block by additive manufacturing.

[0005] Document FR3096768A1 discloses another exchanger-reactor comprising a first series of stacked wall stages for the flow of a first fluid and a second series of stacked wall stages for the flow of a second fluid. Each stage is in particular divided into an exchange zone and a distribution zone and each of these zones is made up of multiple channels. The exchanger-reactor also comprises protuberances capable of changing at least one direction of a fluid. This exchanger-reactor is produced in one piece by an additive manufacturing process, preferably a laser fusion process on a metal powder bed.

[0006] These heat exchanger-reactor and exchanger manufacturing processes are limited because they do not allow the manufacturing of large heat exchanger-reactors and heat exchangers. It is the size of the machines implementing additive manufacturing that limits the size of the components that can be manufactured by this manufacturing method. In addition, these manufacturing processes impose very long cycle times.

[0007] The present invention aims to effectively remedy these drawbacks by proposing a method for manufacturing an exchanger-reactor or exchanger by additive manufacturing which places less constraints on the size of the exchanger-reactor or exchanger thus manufactured and which is quicker to implement than current solutions.

[0008] The invention then relates to a method for manufacturing an exchanger-reactor or an exchanger comprising a plurality of first stages and a plurality of second stages stacked in a stacking direction,

[0009] - each first stage being divided, following a longitudinal direction which is or thogonal to the stacking direction, into a first heat exchange zone and a first distribution zone, said first heat exchange zone comprising a first plurality of heat exchange channels intended to circulate a first fluid, said first distribution zone comprising a first plurality of distribution channels fluidly connected with said first plurality of heat exchange channels and intended to distribute said first fluid in said first heat exchange zone or to evacuate said first fluid from said first heat exchange zone,

[0010] - each second stage being divided, in the longitudinal direction, into a second heat exchange zone and a second distribution zone, said second heat exchange zone comprising a second plurality of heat exchange channels intended to circulate a second fluid, said second distribution zone comprising a second plurality of distribution channels fluidically connected with said second plurality of heat exchange channels and intended to distribute said second fluid in said second heat exchange zone or to evacuate said second fluid from said second heat exchange zone, said method being characterized in that it comprises at least:

[0011] - a first step of manufacturing said first and second dis zones tribute carried out by means of an additive manufacturing process on a powder bed,

[0012] - a second step of manufacturing said first and second exchange zones heat produced using an additive manufacturing process by depositing material under concentrated energy.

[0013] The invention will be better understood upon reading the following description and examining the accompanying figure. This figure is given only for illustrative purposes but in no way limits the invention.

[0014] [Fig-1] is a schematic representation of a heat exchanger-reactor according to an embodiment of the invention;

[0015] With reference to [Fig.l], the manufacturing method relates to an exchanger-reactor 1 or an exchanger 1. In one embodiment, the method relates to a milli-structured exchanger-reactor or a milli-structured exchanger. This exchanger-reactor 1 comprises a plurality of walls stacked along the stacking direction Z. This exchanger-reactor 1 also comprises at least one first stage and at least one second stage. These stages are delimited by a pair of adjacent walls. Thus the stages are stacked along the stacking direction Z. In one embodiment, the exchanger-reactor 1 comprises more than three stages. In one embodiment the exchanger-reactor 1 or the exchanger 1 comprises a plurality of first stages and a plurality of second stages. Each stage is divided along the longitudinal direction A which is orthogonal to the stacking direction Z, into a heat exchange zone 12, 22 and a distribution zone 11, 21.Thus the first stage defines a first heat exchange zone 12 comprising a first plurality of heat exchange channels intended to circulate at least a first fluid. The second stage defines a second heat exchange zone 22 comprising a second plurality of heat exchange channels intended to circulate at least a second fluid. In this way, the second fluid is placed in indirect heat exchange relationship with the first fluid. Each stage also defines at least one distribution zone 11. Thus the first stage defines a first distribution zone 11 comprising a first plurality of distribution channels fluidly connected with the first plurality of heat exchange channels. Indeed the distribution channels correspond to the extension of the heat exchange channels. Thus the first distribution zone 11 makes it possible to distribute the first. fluid in said first exchange zone 12 or to evacuate the first fluid from said first exchange zone 12. The second stage defines a second distribution zone 21 comprising a second plurality of distribution channels fluidly connected with the second plurality of heat exchange channels. Indeed, the distribution channels correspond to the extension of the heat exchange channels. Thus, the second distribution zone 21 makes it possible to distribute the second fluid in said second exchange zone 22 or to evacuate the second fluid from said second exchange zone 22. [Fig.l] shows the exchange zones 12, 22 and the distribution zones 11, 21 superimposed on each other in the stacking direction Z.

[0016] In one embodiment, the pluralities of channels have, for example, a cylindrical section whose diameter is of the order of a few millimeters. In one embodiment, these channels have a square section. In one embodiment, the channels located in said first and / or second exchange zone 12, 22 are rectilinear channels.

[0017] According to the method of the invention, a first step of the method of the invention consists of manufacturing the first and second distribution zones 11, 21 of the first and second stages. The manufacturing of the first and second distribution zones 11, 21 is carried out by means of a manufacturing method called LPBF (acronym for Laser Powder Bed Fusion in English), that is to say by laser fusion on a powder bed. For example, a possible method of the invention is the SLM (acronym for Selective Laser Melting in English) or SLS (acronym for Selective Laser Sintering in English), that is to say by melting or sintering a powder bed. LPBF type methods make it possible to produce complex geometries, it is therefore a method suitable for manufacturing the first and second distribution zones 11, 21.This manufacturing technique thus makes it possible to produce the first and second distribution zones 11, 21 with good resolution. In one embodiment, the channels of the first and second distribution zones 11, 21 are millimeter channels, that is to say channels whose cylindrical section has a diameter of the order of a few millimeters. According to the invention, these millimeter channels are also obtained with great precision.

[0018] First, a metal powder is supplied to the LPBF process machine. Then the first and second distribution zones 11, 21 are built up by melting or sintering the powder layer by layer along the longitudinal axis A. Then, the distribution zones 11, 21 are freed from the unmelted powder. The distribution zones 11, 21 are also cleaned. In one embodiment, surfacing is carried out on the surfaces of the distribution zones 11, 21. This surfacing allows in particular to improve the surface condition, for example it allows to reduce the average surface roughness. This surfacing can for example be carried out by a machining operation such as a milling operation.

[0019] In one embodiment, a plurality of distribution zones 11, 21 are produced by LPBF.

[0020] In one embodiment, several additional distribution zones 11, 21 are produced by LPBF. In one embodiment, these additional distribution zones 11, 21 are assembled together with the first and second distribution zones 11, 21 for example by welding or brazing.

[0021] According to the method of the invention, a second step of the method of the invention consists of manufacturing the first and second exchange zones 12, 22. The exchange zones 12, 22 are produced using a manufacturing method called DED (acronym for Directed Energy Deposition in English), i.e. by concentrated energy deposition. The additive manufacturing method by concentrated energy deposition has the particularity of allowing faster manufacturing. In one embodiment, the first and second heat exchange zones 12, 22 do not have a complex geometry. The additive manufacturing method by concentrated energy deposition is thus suitable for manufacturing the exchange zones 12, 22. This manufacturing according to the invention makes it possible to increase productivity by being faster than the production of these exchange zones 12, 22 by an LPBF method.In one embodiment, the first and second heat exchange zones 12, 22 consist of straight channels. Thus, the production of these exchange zones 12, 22 is even faster.

[0022] The previously constructed distribution zones 11, 21 are therefore placed in a concentrated energy deposition additive manufacturing machine for the manufacture of the exchange zones 12, 22. The channels of the exchange zones are manufactured along the longitudinal axis A, in continuity with the distribution channels. Thanks to the method of the invention, the heat exchange zone 12, 22 can be produced in a single operation. In one embodiment, the channels of the exchange zones are straight and do not have any geometric complexity. Thus, the manufacturing method according to the invention is faster than the methods of the prior art. Furthermore, thanks to the concentrated energy deposition additive manufacturing method, the thickness of the walls of the channels obtained is less than 1.5 mm. In one embodiment of the invention, the channels have a square cross-section. Thus, the manufacture of the exchange zones 12, 22 is even faster.

[0023] The exchange zones 12, 22 are thus manufactured directly on the distribution zones 11, 21. It is then not necessary to carry out a welding step between the distribution zones 11, 21 and the exchange zones 12, 22. The manufacture of the exchanger-reactor 1 or exchanger 1 requires fewer manufacturing steps and is thus faster thanks to the method of the invention.

[0024] Thanks to the method of the invention, the heat exchanger-reactor 1 or the heat exchanger 1 can have larger dimensions than those of the exchanger-reactor and exchanger of the prior art. It is known that the manufacturing chamber of an LPBF machine typically makes it possible to achieve a component with a maximum width of between 500 and 800 mm and a maximum height of between 500 and 1000 mm. It is known that the manufacturing chamber of a DED machine typically makes it possible to achieve a component with a maximum width of between 900 and 1000 mm and a maximum height of between 900 and 1500 mm. Thus, thanks to the combination of the two additive manufacturing methods, the dimensions of the exchanger-reactor 1 obtained are larger than if the exchanger-reactor 1 or the exchanger 1 had been produced using only an LPBF type method.

Claims

[Claim 1] Claims A method of manufacturing an exchanger-reactor or an exchanger comprising a plurality of first stages and a plurality of second stages stacked in a stacking direction (Z), - each first stage being divided, in a longitudinal direction (A) which is orthogonal to the stacking direction (Z), into a first heat exchange zone (12) and a first distribution zone (11), said first heat exchange zone (12) comprising a first plurality of heat exchange channels intended to circulate a first fluid, said first distribution zone (11) comprising a first plurality of distribution channels fluidically connected with said first plurality of heat exchange channels and intended to distribute said first fluid in said first heat exchange zone (12) or to evacuate said first fluid from said first heat exchange zone (12), - each second stage being divided,along the longitudinal direction (A), into a second heat exchange zone (22) and a second distribution zone (21), said second heat exchange zone (22) comprising a second plurality of heat exchange channels intended to circulate a second fluid, and at least one second distribution zone (21) comprising a second plurality of distribution channels fluidically connected with said second plurality of heat exchange channels and intended to distribute said second fluid in said second heat exchange zone (22) or to evacuate said second fluid from said second heat exchange zone (22), said method being characterized in that it comprises at least:, - a first step of manufacturing said first and second distribution zones (11, 21) carried out by means of an additive manufacturing process on a powder bed, - a second step of manufacturing said first and second heat exchange zones (12, 22) carried out by means of an additive manufacturing process by concentrated energy deposition.

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