A powder metallurgy preparation device and method for a foamed metal catalyst bed for hydrogen production

Abstract

The invention discloses a powder metallurgy preparation device and method for a foamed metal catalyst bed for hydrogen production, and relates to the technical field of products made from metal powder, comprising a lower base plate, an upper base plate, an inner straight mold, an inner oblique mold, a heat exchange tube group, an outer mold, an outer ring, a cover plate, an inner ring, etc.; a closed space surrounded by the lower base plate, the inner straight mold, the inner oblique mold, the heat exchange tube group, the outer mold and the cover plate is a molding inner cavity; a mixture of metal powder and a foaming agent is foamed and sintered in the molding inner cavity; the inner cylindrical surface and the outer cylindrical surface of the molding inner cavity are the inner facade and the outer facade respectively, and the inner facade and the outer facade are both irregular curved surfaces with periodic changes and uneven surfaces, and the surface area is significantly increased compared with the cylindrical surface; the heat exchange tube group is a consumable part, and together with the sintered foamed metal, a foamed metal catalyst bed assembly is formed, and each time the foamed metal is sintered, a heat exchange tube group is consumed; both ends of the heat exchange tube group are transparent, so that the mixture in the molding inner cavity is heated more evenly during foaming and sintering.

Description

Technical Field

[0001] The invention relates to the technical field of products made from metal powders, and in particular to a powder metallurgy preparation device and method for a foamed metal catalyst bed for hydrogen production. Background Art

[0002] Foam metal is a special metal material containing foam pores, which has many advantages and broad application prospects. Regarding the preparation of foam metal, the patent with announcement number CN109530701B proposes a foaming mold for preparing foam metal by powder metallurgy. At the same time, the patent with announcement number CN109652674B proposes a foaming method for preparing foam metal by powder metallurgy. Combined with the aforementioned foaming mold, plate-shaped foam metal can be prepared by sintering a mixture of metal powder and foaming agent.

[0003] The foam metal obtained by the above process has air permeability and a large specific surface area. It is used as a catalytic carrier and carries a catalyst to carry out methanol reforming to produce hydrogen, which will achieve technical requirements such as fast chemical reaction rate and high methanol conversion rate. It is known that the existing foam metal catalyst beds for hydrogen production are mostly hollow cylindrical structures (such as the invention with publication number CN116062687A), similar to honeycomb coal. The mold for preparing the foam metal with this structure is relatively simple, similar to the honeycomb coal mold. However, in order to further improve the chemical reaction rate and further improve the methanol conversion rate, the structure of the honeycomb coal-shaped foam metal catalyst bed is improved, and the inner and outer surfaces of the corresponding foam metal are shaped differently and the internal heat pipe channel is complicated, so that the external surface area is significantly increased and the temperature gradient is more uniform during heating. In this case, its special structure greatly increases the difficulty of research and development of its preparation device and method. Summary of the invention

[0004] The purpose of the present invention is to provide a powder metallurgy preparation device for efficiently preparing a foam metal catalyst bed for hydrogen production with a special-shaped outer surface shape, and to propose a corresponding use method thereof.

[0005] In view of the above technical problems, the technical solution adopted by the present invention is: a powder metallurgy preparation device for a foam metal catalyst bed for hydrogen production, comprising a lower base plate, a support column, an upper base plate, an adjustment handle, an adjustment block, a core shaft, an inner straight mold, an inner oblique mold, a heat exchange tube group, an outer mold, an outer ring, a cover plate, an inner ring, a pressure plate, a limit block, a first screw, and a second screw; the lower base plate is fixedly connected to the upper base plate by a plurality of support columns evenly distributed around the circumference; the adjustment block is fixedly mounted on the lower base plate; an internal thread is arranged in the adjustment block; an external thread is arranged on the adjustment handle; the adjustment handle and the adjustment block are threadedly connected by internal and external threads; the lower part of the core shaft is rotatably mounted on the lower base plate; external spline structures are arranged at both ends of the core shaft; internal spline holes are arranged on the adjustment handle and the center of the inner ring; the lower end of the core shaft The outer spline structure is inserted into the inner spline hole of the adjusting handle; the inner spline hole of the inner ring is sleeved on the outer spline structure at the upper end of the core shaft; the outer ring is rotatably mounted on the upper base plate; the cover plate is buckled between the inner ring and the outer ring; the first ends of multiple pressure plates are fixedly mounted on the upper base plate by first screws evenly distributed around the circumference; the second end of each pressure plate is used to contact and press the cover plate; the first ends of multiple limit blocks are fixedly mounted on the outer ring evenly distributed around the circumference by second screws; the second end of each limit block is used to be fixedly connected to the upper base plate by a second screw; multiple inner straight molds and inner oblique molds evenly distributed around the circumference and alternately arranged are slidably mounted between the inner ring and the lower base plate; a heat exchange tube group is fixedly mounted between the cover plate and the lower base plate; multiple outer molds evenly distributed around the circumference are slidably mounted between the outer ring and the lower base plate.

[0006] Preferably, the lower base plate is provided with a plurality of circumferentially evenly distributed outer straight grooves, a plurality of circumferentially evenly distributed inner straight grooves 1 and a plurality of circumferentially evenly distributed inner straight grooves 2; the outer ring is provided with a plurality of circumferentially evenly distributed outer arc grooves; the inner ring is provided with a plurality of circumferentially evenly distributed inner arc grooves 1 and a plurality of circumferentially evenly distributed inner arc grooves 2; an inner sliding column 1 is provided at each of the two ends of the inner straight mold; an inner sliding column 2 is provided at each of the two ends of the inner inclined mold; an outer sliding column is provided at each of the two ends of the outer mold; the line shape of the center line of the outer arc groove and the center line of the inner arc groove 1 are both a section of circular arc line; the line shape of the center line of the inner arc groove 2 is two sections of circular arc lines connected to each other and tangent at the connection; the inner sliding column 1 is used for sliding cooperation with the inner straight groove 1 and the inner arc groove 1; the inner sliding column 2 is used for sliding cooperation with the inner straight groove 2 and the inner arc groove 2; the outer sliding column is used for sliding cooperation with the outer straight groove and the outer arc groove.

[0007] Preferably, the outer ring is used to control the separation and closing of all outer molds; the inner ring is used to control the separation and closing of all inner straight molds and inner oblique molds; the enclosed space surrounded by the lower base plate, the closed inner straight mold, the closed inner oblique mold, the heat exchange tube group, the closed outer mold and the cover plate is the molding inner cavity; the outer side surface of the space body formed by the closed inner straight mold and the inner oblique mold, that is, the inner cylindrical surface of the molding inner cavity is the inner facade; the inner side surface of the space body formed by the closed outer mold, that is, the outer cylindrical surface of the molding inner cavity is the outer facade; both the inner facade and the outer facade are curved surfaces that change periodically in a wavy shape along the axial and circumferential directions, and such curved surfaces areo - xyz The parametric equation in the space rectangular coordinate system is:

[0008] ;

[0009] Where, R is the radius of the base circle, mm; A is the amplitude of fluctuation, mm; K is the frequency of fluctuation, for the exterior facade, K is an integer greater than or equal to 3, for the interior facade, K is an even number greater than or equal to 4; T is the frequency of fluctuation along the z Change period in the axial direction; H-height boundary value, mm; t -Angular position parameter, rad.

[0010] Preferably, when all outer molds are closed, the contact surfaces of every two adjacent outer molds are xoy The projection on the plane is a straight line segment, and the straight line on which the straight line segment lies passes through the origin o ; The number of inner straight molds and inner oblique molds is the same; when all inner straight molds and inner oblique molds are closed, the contact surface between the first inner straight mold and its two adjacent inner oblique molds is xoy The projection on the plane is two parallel straight line segments, and the straight lines parallel to these two straight line segments and equidistant from them pass through the origin. o .

[0011] Preferably, the heat exchange tube group includes an outer tube joint, a corrugated tube, and an inner tube joint; the corrugated tube is wavy in the circumferential direction, and has a plurality of wave crests and wave troughs, an outer tube joint is arranged on each wave crest, and an inner tube joint is arranged on each wave trough.

[0012] Preferably, the center line of the corrugated tube is a tube curve. o - xyz The parametric equation in the space rectangular coordinate system is:

[0013] ;

[0014] Where, r-radial distribution radius, mm; h-axial amplitude, mm; s-wave number; u -Angular position parameter, rad.

[0015] Preferably, the lower base plate is provided with a plurality of circumferentially evenly distributed positioning holes 1 for sleeve-fitting the inner pipe joint; the cover plate is provided with a plurality of circumferentially evenly distributed positioning holes 2 for sleeve-fitting the outer pipe joint.

[0016] Preferably, all the outer straight grooves, the inner straight groove 1, the inner straight groove 2, the outer arc grooves, the inner arc groove 1 and the inner arc groove 2 are located outside the inner space of the forming inner cavity.

[0017] Preferably, it also includes bolts and nuts; the lower base plate, the support columns and the upper base plate are fixedly connected by the bolts and nuts.

[0018] The present invention also provides a sintering preparation method of a powder metallurgy preparation device for a foamed metal catalyst bed for hydrogen production, comprising the following steps:

[0019] Step 1: mixing metal powder or alloy powder with a foaming agent to obtain a mixed material;

[0020] Step 2: Manually rotate the adjustment handle to drive the inner ring through the mandrel, and the inner ring drives all the inner straight molds and inner inclined molds to slide until they are completely closed;

[0021] Step 3: Manually rotate the limit block to drive the outer ring, which drives all the outer molds to slide until they are completely closed, and then fix the second end of the limit block to the upper base plate through the second screw;

[0022] Step 4: insert a new heat exchange tube group on the lower bottom plate, so that all the inner tube joints are inserted into all the positioning holes 1, and then pour the prepared mixed material into the molded inner cavity for several times. After each pouring of the mixed material, it must be compacted manually or with the help of tools until the last time the mixed material is poured, so that the positioning hole 2 is aligned with the outer tube joint, and then manually insert the cover plate, compact the mixed material with the cover plate, and then press the cover plate with the second end of the pressing plate, and tighten the first screw at the first end of the pressing plate to lock the entire molded inner cavity;

[0023] Step 5: Place the entire device in an industrial furnace for foaming, the temperature is controlled at 650°C to 690°C, the bottom of the multiple bolts serve as the fulcrum of the device in the industrial furnace, and the foaming time is controlled at 1-2 hours;

[0024] Step six: After foaming is completed, take out the entire device, cool it naturally to room temperature, then manually remove all the first screws and pressure plates, manually remove the second screws at the second end of all the limit blocks, and manually rotate the adjustment handle and the limit block to drive all the outer molds to move outward to the maximum separation state, and drive all the inner straight molds and inner inclined molds to move inward and shrink to the minimum separation state. Then, by dragging the outer pipe joint, remove the sintered metal foam catalyst bed together with the heat exchange tube group and the cover plate. The metal foam catalyst bed and the heat exchange tube group constitute an integrated component. Finally, remove the cover plate from the metal foam catalyst bed and the heat exchange tube group.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) The inner and outer facades of the molding cavity are both irregular curved surfaces with periodic changes and uneven surfaces, which can sinter a foam metal catalyst bed of a corresponding shape. Compared with the honeycomb coal-shaped foam metal catalyst bed in the prior art, the outer surface area is increased by 10% to 15%, which significantly improves the use effect; (2) The heat exchange tube group is a consumable part, and together with the sintered foam metal, it constitutes a foam metal catalyst bed assembly. Each time the foam metal is sintered, a heat exchange tube group is consumed. However, both ends of the heat exchange tube group are transparent, and the main body adopts a periodic wavy structure, so that the mixed material in the molding cavity is heated more evenly during foaming and sintering, and the molding effect is better; (3) The lower base plate is arranged in conjunction with the linkage transmission structure of the outer ring and the inner ring, so that the structure of the entire device is compact, and the position switching of all inner straight molds, inner inclined molds and outer molds is more efficient and smooth, so that efficient demolding after sintering is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional view of the sintered state of the overall structure of the present invention.

[0027] Figure 2 It is a perspective projection diagram of the sintered state of the overall structure of the present invention.

[0028] Figure 3 It is a schematic diagram of the mechanism principle of the sintering state of the overall structure of the present invention.

[0029] Figure 4 It is a schematic diagram of the inner cavity structure of the molding in the sintered state of the present invention.

[0030] Figure 5 It is a cross-sectional view of the overall structure of the present invention in a demoulding state.

[0031] Figure 6 It is a perspective projection diagram of the demoulding state of the overall structure of the present invention.

[0032] Figure 7 It is a schematic diagram of the mechanism principle of the overall structure of the present invention in the demoulding state.

[0033] Figure 8 It is a schematic diagram of the molding inner cavity structure in the demoulding state of the present invention.

[0034] Fig. 9 It is a schematic diagram of the parts structure of the lower base plate of the present invention.

[0035] Fig.10 This is a diagram showing the change in posture of the internal structure of the present invention from the sintering state to the demoulding state.

[0036] Fig.11 It is a schematic diagram of the parts structure of the outer ring of the present invention.

[0037] Fig.12It is a schematic diagram of the parts structure of the inner ring of the present invention.

[0038] Fig.13 This is a schematic diagram of the appearance of the sintered state of the overall structure of the present invention. Figure 1 .

[0039] Fig.14 This is a schematic diagram of the appearance of the sintered state of the overall structure of the present invention. Figure 2 .

[0040] Fig.15 It is a structural cross-sectional view of the heat exchange tube group of the present invention.

[0041] Fig.16 This is a schematic diagram of the sintered finished product of the foam metal catalyst bed for hydrogen production of the present invention.

[0042] In the figure: 1-lower base plate; 2-support column; 3-upper base plate; 4-positioning handle; 5-positioning block; 6-mandrel; 7-inner straight mold; 8-inner inclined mold; 9-heat exchange tube group; 10-outer mold; 11-outer ring; 12-cover plate; 13-inner ring; 14-pressing plate; 15-limiting block; 16-bolt; 17-nut; 18-first screw; 19-second screw; 20-outer facade; 21-inner facade; 22-metal Foam catalytic bed; 101-outer straight groove; 102-positioning hole one; 103-inner straight groove one; 104-inner straight groove two; 701-inner sliding column one; 801-inner sliding column two; 901-outer pipe joint; 902-wave pipe; 903-inner pipe joint; 904-tube curve; 1001-outer sliding column; 1101-outer arc groove; 1201-positioning hole two; 1301-inner arc groove one; 1302-inner arc groove two. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods, wherein the accompanying drawings are only used for exemplary descriptions and represent only schematic diagrams rather than actual drawings, and should not be understood as limiting the present invention; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted.

[0044] Figures 1 to 15 A preferred embodiment of the present invention is given. In this embodiment, the maximum outer diameter of the device body is 205 mm, and the maximum height of the device body is 128 mm; the bolt 16 is of M12×110; the first screw 18 is of M8×12 hexagon socket head screw; the second screw 19 is of M4×12 hexagon socket head screw; the outer pipe joint 901 and the inner pipe joint 903 are both of two-pipe diameter; the structural schematic diagram of the sintered product based on the principle of the present invention is shown in FIG. Fig.16 shown.

[0045] like Figure 1 , Figure 5 , Fig.13 and Fig.14 As shown, the lower base plate 1 is fixedly connected to the upper base plate 3 by eight support columns 2 evenly distributed around the circumference; in this embodiment, the lower base plate 1, the support columns 2 and the upper base plate 3 are fixedly connected by bolts 16 and nuts 17; the adjustment block 5 is fixedly installed on the lower base plate 1; the adjustment block 5 is provided with an internal thread; the adjustment handle 4 is provided with an external thread; the adjustment handle 4 and the adjustment block 5 are threadedly connected by internal and external threads; the lower part of the core shaft 6 is rotatably installed on the lower base plate 1; the two ends of the core shaft 6 are provided with external spline structures; the adjustment handle 4 and the center of the inner ring 13 are provided with internal spline holes; the external spline structure at the lower end of the core shaft 6 is inserted into the internal spline hole of the adjustment handle 4; the internal spline hole of the inner ring 13 is sleeved on the external spline structure at the upper end of the core shaft 6; the external spline structure can slide axially along the core shaft 6 in the internal spline hole; the outer ring 1 1 is rotatably mounted on the upper base plate 3; the cover plate 12 is buckled between the inner ring 13 and the outer ring 11; the first ends of the four pressing plates 14 are fixedly mounted on the upper base plate 3 by the first screws 18 in a circumferentially uniform manner; the second end of each pressing plate 14 is used to contact and press the cover plate 12; the first ends of the two limit blocks 15 are fixedly mounted on the outer ring 11 in a circumferentially uniform manner by the second screws 19; the second end of each limit block 15 is used to be fixedly connected to the upper base plate 3 by a second screw 19; eight inner straight molds 7 and inner oblique molds 8 that are uniformly distributed and alternately arranged in the circumference are slidably mounted between the inner ring 13 and the lower base plate 1, that is, four inner straight molds 7 and four inner oblique molds 8; a heat exchange tube group 9 is fixedly mounted between the cover plate 12 and the lower base plate 1; eight outer molds 10 that are uniformly distributed in the circumference are slidably mounted between the outer ring 11 and the lower base plate 1.

[0046] like Fig. 9 As shown, the lower base plate 1 is provided with eight outer straight grooves 101 evenly distributed around the circumference, four inner straight grooves 103 evenly distributed around the circumference, and four inner straight grooves 2 104 evenly distributed around the circumference.

[0047] like Fig.11 As shown, the outer ring 11 is provided with eight outer arc grooves 1101 evenly distributed around the circumference, and the center line of the outer arc groove 1101 is a segment of an arc line, namely, arc mn.

[0048] like Fig.12 As shown, four inner arc grooves 1301 evenly distributed around the circumference and four inner arc grooves 2 1302 evenly distributed around the circumference are provided on the inner ring 13; the center line of the inner arc groove 1301 is a segment of circular arc, i.e., arc df; the center line of the inner arc groove 2 1302 is two segments of circular arcs connected to each other and tangent at the connection, i.e., arc ac, and arc ac is formed by connecting arc ab and arc bc.

[0049] like Figure 4 and Figure 8As shown, an inner slide column 1 701 is provided at each end of the inner straight mold 7; an inner slide column 2 801 is provided at each end of the inner inclined mold 8; an outer slide column 1001 is provided at each end of the outer mold 10; the inner slide column 1 701 is used for sliding cooperation with the inner straight groove 103 and the inner arc groove 1 1301; the inner slide column 2 801 is used for sliding cooperation with the inner straight groove 2 104 and the inner arc groove 2 1302; the outer slide column 1001 is used for sliding cooperation with the outer straight groove 101 and the outer arc groove 1101.

[0050] like Figure 1 , Figure 4 , Figure 5 and Figure 8 As shown, the outer ring 11 is used to control the separation and closing of all outer molds 10; the inner ring 13 is used to control the separation and closing of all inner straight molds 7 and inner oblique molds 8; the enclosed space surrounded by the lower base plate 1, the closed inner straight mold 7, the closed inner oblique mold 8, the heat exchange tube group 9, the closed outer mold 10 and the cover plate 12 is the molding inner cavity; the outer side surface of the space body formed by the closed inner straight mold 7 and the inner oblique mold 8, that is, the inner cylindrical surface of the molding inner cavity is the inner facade 21; the inner side surface of the space body formed by the closed outer mold 10, that is, the outer cylindrical surface of the molding inner cavity is the outer facade 20; the inner facade 21 and the outer facade 20 are both curved surfaces that change periodically in a wavy shape along the axial direction and the circumferential direction; in this embodiment, the outer facade 20 is o - xyz The parametric equation in the space rectangular coordinate system is:

[0051] ;

[0052] Interior facade 21 o - xyz The parametric equation in the space rectangular coordinate system is:

[0053] ;

[0054] In the above two formulas, t - angular position parameter, rad; in particular, the shape structure of the outer facade 20 and the inner facade 21 of this embodiment is based on the above equations, around z The axis rotates 11.25°. xoy The projection of the plane is Fig.10 shown.

[0055] like Fig.10 As shown, when all outer molds 10 are closed, the contact surfaces of every two adjacent outer molds 10 are xoy The projection on the plane is a straight line segment, and the straight line on which the straight line segment lies passes through the origin o; When all the inner straight molds 7 and the inner oblique molds 8 are closed, the projections of the contact surfaces of the first inner straight mold 7 and its two adjacent inner oblique molds 8 on the xoy plane are two parallel straight line segments, and the straight lines parallel to and equidistant from the two straight line segments ( Fig.10 In y Axis) through the origin o .

[0056] like Fig.15 As shown, the heat exchange tube group 9 includes an outer tube joint 901, a wave tube 902, and an inner tube joint 903; the wave tube 902 is wavy in the circumferential direction, and has eight wave crests and wave troughs, each wave crest is provided with an outer tube joint 901, and each wave trough is provided with an inner tube joint 903; the center line of the wave tube 902 is a tube curve 904. In this embodiment, the tube curve 904 is o - xyz The parametric equation in the space rectangular coordinate system is:

[0057] ;

[0058] In the formula, u - Angular position parameter, rad; in this embodiment, the outer diameter of the wave tube 902 is 6.86 mm.

[0059] like Figure 3 , Figure 7 and Fig. 9 As shown, the lower base plate 1 is provided with eight circumferentially evenly distributed positioning holes 102 for sleeve-fitting the inner pipe joint 903; the cover plate 12 is provided with eight circumferentially evenly distributed positioning holes 1201 for sleeve-fitting the outer pipe joint 901.

[0060] like Figure 2 and Figure 6 As shown, all the outer straight grooves 101, the inner straight groove 103, the inner straight groove 104, the outer arc groove 1101, the inner arc groove 1301 and the inner arc groove 2 1302 are located outside the inner space of the molding cavity.

[0061] exist Figure 2 , Figure 3 , Figure 6 and Figure 7 In the figure, the dotted line is the outline of the part that is viewed from above.

[0062] The method for sintering using the device described in this embodiment comprises the following steps:

[0063] Step 1: mixing metal powder or alloy powder with a foaming agent to obtain a mixed material;

[0064] Step 2: Manually rotate the adjustment handle 4, which is driven by the core shaft 6 to drive the inner ring 13, and the inner ring 13 drives all the inner straight molds 7 and the inner inclined molds 8 to slide until they are completely closed;

[0065] Step 3: Manually rotate the limit block 15 to drive the outer ring 11, and the outer ring 11 drives all the outer molds 10 to slide until they are completely closed, and then fix the second end of the limit block 15 to the upper base plate 3 through the second screw 19;

[0066] Step 4: insert a new heat exchange tube group 9 on the lower base plate 1, so that all the inner tube joints 903 are inserted into all the positioning holes 1 102, and then pour the prepared mixed material into the molded inner cavity for multiple times, and compact it manually or with the help of tools after each pouring of the mixed material, until the last time the mixed material is poured, so that the positioning hole 2 1201 is aligned with the outer tube joint 901, and then manually insert the cover plate 12, and compact the mixed material with the cover plate 12, and then press the cover plate 12 with the second end of the pressing plate 14, and tighten the first screw 18 at the first end of the pressing plate 14 to lock the entire molded inner cavity;

[0067] Step 5: Place the entire device in an industrial furnace for foaming, the temperature is controlled at 680°C, the bottoms of the eight bolts 16 serve as the fulcrum of the device in the industrial furnace, and the foaming time is controlled at 1.5 hours;

[0068] Step six: After foaming is completed, take out the entire device, cool it naturally to room temperature, then manually remove all the first screws 18 and the pressure plate 14, manually remove the second screws 19 at the second end of all the limit blocks 15, and manually rotate the adjustment handle 4 and the limit block 15 to drive all the outer molds 10 to move outward to the maximum separation state, and drive all the inner straight molds 7 and the inner inclined molds 8 to move inward and shrink to the minimum separation state. Then, by dragging the outer pipe joint 901, the sintered metal foam catalyst bed 22, together with the heat exchange tube group 9 and the cover plate 12, are removed. The metal foam catalyst bed 22 and the heat exchange tube group 9 constitute an integrated component. Finally, the cover plate 12 is removed from the metal foam catalyst bed 22 and the heat exchange tube group 9.

[0069] The mode switching principle of the demoulding state and the sintering state of the present invention is as follows: Fig.11 As shown, in this embodiment, the value of ∠mon is 22.5°, the center line of the outer straight groove 101 is a straight line segment, and its length is equal to the length difference between the line segment om and the line segment on; the two outer slide posts 1001 on the outer mold 10 are slidably installed in the outer straight groove 101 and the outer arc groove 1101 respectively; when the outer slide post 1001 in the outer arc groove 1101 moves from the starting point to the end point, since the outer straight groove 101 is fixed, the outer slide post 1001 in the outer straight groove 101 will be forced to move from the starting point to the end point, that is, the degree of freedom of the mechanism composed of the outer ring 11, the outer mold 10 and the lower base plate 1 is 1. When the outer ring 11 reciprocates within the range of 0° to 22.5°, it will drive the outer mold 10 to move back and forth between the demoulding state and the sintering state. Fig.10 ; Similarly, if Fig.12As shown, the values ​​of ∠aoc and ∠dof are both 90°, the values ​​of ∠aob and ∠doe are both 60°, the center line of the inner straight groove 103 is a straight line segment, and its length is equal to the length difference between the line segment od and the line segment of; the center line of the inner straight groove 104 is a straight line segment, and its length is equal to the length difference between the line segment oa and the line segment oc; the two inner slide posts 1 701 on the inner straight mold 7 are slidably installed in the inner straight groove 103 and the inner arc groove 1301 respectively; when the inner slide post 1 701 in the inner arc groove 1301 moves from the starting point to the end point, since the inner straight groove 103 is fixed, it will force the inner slide post 1 701 in the inner straight groove 103 to move from the starting point to the end point. Move to the end point, that is, the degree of freedom of the mechanism composed of the inner ring 13, the inner straight mold 7 and the lower base plate 1 is 1; the two inner slide columns 801 on the inner inclined mold 8 are slidably installed in the inner straight groove 104 and the inner arc groove 1302 respectively; when the inner slide column 801 in the inner arc groove 1302 moves from the starting point to the end point, since the inner straight groove 104 is fixed, the inner slide column 801 in the inner straight groove 104 will be forced to move from the starting point to the end point, that is, the degree of freedom of the mechanism composed of the inner ring 13, the inner inclined mold 8 and the lower base plate 1 is 1; when the inner ring 13 reciprocates within the range of 0° to 90°, it will drive the inner straight mold 7 and the inner inclined mold 8 to move back and forth between the demoulding state and the sintering state, refer to Fig.10 ; It should be noted that if Fig.12 As shown, in the arc segment ab, the inner inclined die 8 does not undergo radial displacement, which is to make way for movement, that is, in the 60° driving rotation range corresponding to the arc segment ab, the inner straight die 7 first displaces, corresponding to the arc segment de, and then in the movement range corresponding to the arc bc and the arc ef, the inner straight die 7 and the inner inclined die 8 displace simultaneously. At this time, the inner straight die 7 and the inner inclined die 8 do not contact each other, and their movements do not interfere with each other.

[0070] exist Fig.10 In the figure, the solid line is the sintering state of the inner cavity, and the dotted line is the demoulding state of the inner cavity. Fig.10 The dotted contour in the figure does not interfere with the solid contour in the sintered state. Fig.16 The sintered product shown can be easily taken out along the axial direction of the mandrel 6 in the demoulding state.

Claims

1. A powder metallurgy preparation device for a foamed metal catalyst bed for hydrogen production, comprising a lower base plate (1), a support column (2), an upper base plate (3), a position adjustment handle (4), a position adjustment block (5), a mandrel (6), an inner straight mold (7), an inner oblique mold (8), a heat exchange tube group (9), an outer mold (10), an outer ring (11), a cover plate (12), an inner ring (13), a pressure plate (14), a limit block (15), a first screw (18), and a second screw (19), characterized in that: The lower base plate (1) is fixedly connected to the upper base plate (3) via a plurality of circumferentially evenly distributed support columns (2); the adjusting block (5) is fixedly mounted on the lower base plate (1); an internal thread is provided inside the adjusting block (5); an external thread is provided on the adjusting handle (4); the adjusting handle (4) and the adjusting block (5) are threadedly connected via the internal thread and the external thread; the lower part of the mandrel (6) is rotatably mounted on the lower base plate (1); external spline structures are provided at both ends of the mandrel (6); internal spline holes are provided at the center of the adjusting handle (4) and the inner ring (13); the external spline structure at the lower end of the mandrel (6) is inserted into the internal spline hole of the adjusting handle (4); the internal spline hole of the inner ring (13) is sleeved on the external spline structure at the upper end of the mandrel (6); the outer ring (11) is rotatably mounted on the upper base plate (3) The cover plate (12) is buckled between the inner ring (13) and the outer ring (11); the first ends of the plurality of pressure plates (14) are fixedly mounted on the upper base plate (3) by means of first screws (18) in a circumferentially uniform manner; the second end of each pressure plate (14) is used to contact and press the cover plate (12); the first ends of the plurality of limit blocks (15) are fixedly mounted on the outer ring (11) in a circumferentially uniform manner by means of second screws (19); the second end of each limit block (15) is used to be fixedly connected to the upper base plate (3) by means of a second screw (19); a plurality of inner straight molds (7) and inner oblique molds (8) that are evenly distributed around the circumference and alternately arranged are slidably mounted between the inner ring (13) and the lower base plate (1); a heat exchange tube group (9) is fixedly mounted between the cover plate (12) and the lower base plate (1); A plurality of circumferentially evenly distributed outer molds (10) are slidably mounted between the outer ring (11) and the lower base plate (1); a plurality of circumferentially evenly distributed outer straight grooves (101), a plurality of circumferentially evenly distributed inner straight grooves 1 (103) and a plurality of circumferentially evenly distributed inner straight grooves 2 (104) are arranged on the lower base plate (1); a plurality of circumferentially evenly distributed outer arc grooves (1101) are arranged on the outer ring (11); a plurality of circumferentially evenly distributed inner arc grooves 1 (1301) and a plurality of circumferentially evenly distributed inner arc grooves 2 (1302) are arranged on the inner ring (13); an inner sliding column 1 (701) is arranged at each end of the inner straight mold (7); an inner sliding column 2 (801) is arranged at each end of the inner oblique mold (8); an outer sliding column (1001) is arranged at each end of the outer mold (10); the outer arc groove (11 The center line of the inner arc groove (1301) and the center line of the inner arc groove (1301) are both arc lines; the center line of the inner arc groove (1302) is two arc lines connected to each other and tangent at the connection, wherein the center of the first arc line is located on the axis of the inner ring (13); the inner sliding column (701) is used for sliding cooperation with the inner straight groove (103) and the inner arc groove (1301); the inner sliding column (801) is used for sliding cooperation with the inner straight groove (104) and the inner arc groove (1302); when the inner sliding column (801) moves along the first arc line in the inner arc groove (1302), the inner inclined mold (8) does not undergo radial displacement relative to the inner ring (13), and is used to make way for the movement of the inner straight mold (7) relative to the inner ring (13);The outer sliding column (1001) is used for slidingly cooperating with the outer straight groove (101) and the outer arc groove (1101); the outer ring (11) is used for controlling the separation and closing of all the outer molds (10); the inner ring (13) is used for controlling the separation and closing of all the inner straight molds (7) and the inner inclined molds (8); the closed space surrounded by the lower base plate (1), the closed inner straight mold (7), the closed inner inclined mold (8), the heat exchange tube group (9), the closed outer mold (10) and the cover plate (12) is the molding space. Inner cavity; the outer side surface of the space body formed by the closed inner straight mold (7) and the inner oblique mold (8), that is, the inner cylindrical surface of the molded inner cavity is the inner facade (21); the inner side surface of the space body formed by the closed outer mold (10), that is, the outer cylindrical surface of the molded inner cavity is the outer facade (20); the inner facade (21) and the outer facade (20) are both curved surfaces that change in a periodic wave shape along the axial direction and the circumferential direction; when all the outer molds (10) are closed, the contact surfaces of every two adjacent outer molds (10) are; xoy The projection on the plane is a straight line segment, and the straight line on which the straight line segment lies passes through the origin o ; The number of inner straight dies (7) and inner oblique dies (8) is the same; when all inner straight dies (7) and inner oblique dies (8) are closed, the contact surface between the first inner straight dies (7) and its two adjacent inner oblique dies (8) is xoy The projection on the plane is two parallel straight line segments, and the straight lines parallel to these two straight line segments and equidistant from them pass through the origin. o The heat exchange tube group (9) comprises an outer tube joint (901), a corrugated tube (902), and an inner tube joint (903); the corrugated tube (902) is wavy in the circumferential direction and has a plurality of wave crests and wave troughs, an outer tube joint (901) is provided on each wave crest, and an inner tube joint (903) is provided on each wave trough.

2. The powder metallurgy preparation device for a foamed metal catalyst bed for hydrogen production according to claim 1, characterized in that: The curved surface corresponding to the inner facade (21) or the outer facade (20) is o - xyz The parametric equation in the space rectangular coordinate system is: ； Where, R is the radius of the base circle, mm; A is the amplitude of fluctuation, mm; K is the frequency of fluctuation, for the outer facade (20), K is an integer greater than or equal to 3, for the inner facade (21), K is an even number greater than or equal to 4; T is the frequency of fluctuation along the z Change period in the axial direction; H-height boundary value, mm; t -Angular position parameter, rad.

3. The powder metallurgy preparation device for a foamed metal catalyst bed for hydrogen production according to claim 2, characterized in that: The center line of the corrugated tube (902) is the tube curve (904). o - xyz The parametric equation in the space rectangular coordinate system is: ； Where, r-radial distribution radius, mm; h-axial amplitude, mm; s-wave number; u -Angular position parameter, rad.

4. A powder metallurgy preparation device for a foamed metal catalyst bed for hydrogen production as claimed in any one of claims 1 to 3, characterized in that: The lower base plate (1) is provided with a plurality of evenly distributed positioning holes (102) for sleeve-fitting the inner pipe joint (903); the cover plate (12) is provided with a plurality of evenly distributed positioning holes (1201) for sleeve-fitting the outer pipe joint (901).

5. The powder metallurgy preparation device for a foamed metal catalyst bed for hydrogen production according to claim 4, characterized in that: All of the outer straight grooves (101), the inner straight groove one (103), the inner straight groove two (104), the outer arc groove (1101), the inner arc groove one (1301) and the inner arc groove two (1302) are located outside the internal space of the molding inner cavity.

6. The powder metallurgy preparation device for a foamed metal catalyst bed for hydrogen production according to claim 5, characterized in that: It also includes bolts (16) and nuts (17); the lower base plate (1), the support column (2) and the upper base plate (3) are fixedly connected by the bolts (16) and the nuts (17).

7. The sintering preparation method of a powder metallurgy preparation device for a foamed metal catalyst bed for hydrogen production according to claim 6, characterized in that: The following steps are involved: Step 1: mixing metal powder or alloy powder with a foaming agent to obtain a mixed material; Step 2: Manually rotate the adjustment handle (4), which is driven by the core shaft (6) to drive the inner ring (13), and the inner ring (13) drives all the inner straight molds (7) and the inner inclined molds (8) to slide until they are completely closed; Step 3: Manually rotate the limit block (15) to drive the outer ring (11), so that the outer ring (11) drives all the outer molds (10) to slide until they are completely closed, and then fix the second end of the limit block (15) to the upper base plate (3) by means of a second screw (19); Step 4: insert a new heat exchange tube group (9) on the lower base plate (1) so that all the inner tube joints (903) are inserted into all the positioning holes (102), and then pour the prepared mixed material into the molded inner cavity in multiple times. After each pouring of the mixed material, it must be compacted manually or with the help of a tool until the last time the mixed material is poured in, so that the positioning hole (1201) is aligned with the outer tube joint (901), and then manually insert the cover plate (12), compact the mixed material with the cover plate (12), and then press the cover plate (12) with the second end of the pressing plate (14), and tighten the first screw (18) at the first end of the pressing plate (14) to lock the entire molded inner cavity; Step 5: placing the entire device in an industrial furnace for foaming, the temperature is controlled at 650° C. to 690° C., the bottoms of the plurality of bolts (16) serve as the fulcrum of the device in the industrial furnace, and the foaming time is controlled at 1-2 hours; Step 6: After the foaming is completed, the entire device is taken out and naturally cooled to room temperature. Then, all the first screws (18) and the pressure plate (14) are manually removed, and the second screws (19) at the second ends of all the limit blocks (15) are manually removed. By manually rotating the adjustment handle (4) and the limit block (15), all the outer molds (10) are driven to move outward to the maximum separation state, and all the inner straight molds (7) and the inner inclined molds (8) are driven to move inward and shrink to the minimum separation state. Then, by dragging the outer pipe joint (901), the sintered metal foam catalyst bed (22) is removed together with the heat exchange tube group (9) and the cover plate (12). The metal foam catalyst bed (22) and the heat exchange tube group (9) constitute an integrated component. Finally, the cover plate (12) is removed from the metal foam catalyst bed (22) and the heat exchange tube group (9).

Images