JP2017133697A - Chemical heat storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chemical heat storage device capable of transferring heat efficiently to a heating object from a reactor by improving thermal conductivity of the reactor.SOLUTION: A chemical heat storage device includes a reactor and an adsorber connected to the reactor via an NHsupply pipe. The reactor has a plurality of press molded bodies 16A having a curved cross section. The press molded body 16A includes: a heat storage material part 17 made of a pellet-like heat storage material which generates heat by chemically reacting with NH; and a heat transfer member 18 having an L-shaped cross section in which heat conductivity is higher than that of the heat storage material. The heat transfer member 18 is constituted by: a body part 19 for transferring the heat generated from the heat storage material part 17; and an auxiliary part 20 provided so as to bend with respect to the body part 19, at an end part inside the body part 19. A principal surface of the body part 19 is a surface vertical with respect to a press direction of the press molded body 16A.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a chemical heat storage device that heats a heating object provided in an exhaust system of an engine, for example.

As a conventional chemical heat storage device, for example, a device described in Patent Document 1 is known. The chemical heat storage device described in Patent Document 1 includes a heat storage material that generates heat by chemically reacting with ammonia (NH ₃ ), a reactor that heats the oxidation catalyst, and the reactor and the NH ₃ supply pipe. And a reservoir for storing NH ₃ . When NH ₃ is supplied from the reservoir to the reactor, NH ₃ and the heat storage material chemically react to generate heat from the heat storage material, and the oxidation catalyst is heated by the heat.

JP 2013-234625 A

  However, in the above prior art, since the heat conductivity of the heat storage material itself is low, the heat generated from the heat storage material is difficult to be transmitted to the oxidation catalyst (heating object). For this reason, there existed a problem that an oxidation catalyst was not fully heated at the time of heat_generation | fever of a thermal storage material.

  An object of the present invention is to provide a chemical heat storage device capable of efficiently transferring heat from a reactor to an object to be heated by improving the thermal conductivity of the reactor.

  The present invention is a chemical heat storage device for heating an object to be heated, which is arranged around the object to be heated, and is made up of a heat storage material that chemically reacts with the reaction medium to generate heat and stores the heat to desorb the reaction medium. A reactor having a press-molded body including a material part and a heat transfer member having a higher heat conductivity than the heat storage material, a reactor connected to the reactor and the reaction medium so as to circulate, and a reservoir for storing the reaction medium; The heat transfer member has a sheet-like main body portion for transmitting heat generated from the heat storage material portion toward the object to be heated, and the main surface of the main body portion is a surface perpendicular to the pressing direction of the press-molded body. It is characterized by becoming.

  Thus, in the chemical heat storage device of the present invention, the reactor is arranged around the object to be heated, and is made of a heat storage material that chemically reacts with the reaction medium to generate heat and stores the heat to desorb the reaction medium. It has a press-molded body including a heat storage material portion and a heat transfer member having a higher thermal conductivity than the heat storage material. And the heat-transfer member has a sheet-like main-body part for conveying the heat which generate | occur | produced from the thermal storage material part toward a heating target object. By setting it as such a structure, the heat which generate | occur | produced from the thermal storage material part by the chemical reaction with a reaction medium and a thermal storage material comes to be transmitted to a heating target object through the main-body part of a heat-transfer member. Accordingly, the heat conductivity of the press-molded body is increased. Moreover, the press molding body containing a heat storage material part and a heat-transfer member is produced by press molding. At this time, the main surface of the sheet-like main body portion is a surface perpendicular to the pressing direction of the press-molded body. For this reason, when the heat storage material part is pressed together with the heat transfer member during the production of the press-molded body, the main body part of the heat transfer member is not easily crushed. Therefore, the high heat conductivity of the press-molded body can be ensured. As described above, since the thermal conductivity of the reactor is improved, heat can be efficiently transferred from the reactor to the object to be heated.

  The heat transfer member may further include an auxiliary portion provided so as to be bent with respect to the main body portion at an end portion on the heating object side in the main body portion. In such a configuration, since the area of the region for transferring heat to the object to be heated in the heat transfer member becomes large, heat can be transferred from the reactor to the object to be heated more efficiently.

  The press-molded body may be formed by alternately stacking a plurality of heat storage material portions and heat transfer members. By providing a plurality of heat transfer members in this manner, the heat generated from the heat storage material part can easily reach the heat transfer member, so that heat can be more efficiently transferred from the reactor to the object to be heated.

  A plurality of through holes through which the reaction medium passes may be formed in the main body. In such a configuration, since the reaction medium introduced into the heat storage material portion of the reactor moves through the through holes of the main body portion and moves through the heat storage material portion, the reaction medium is rapidly supplied to most of the heat storage material portion. be able to.

  According to the present invention, heat can be efficiently transferred from the reactor to the object to be heated by improving the thermal conductivity of the reactor.

It is a schematic block diagram which shows the exhaust gas purification system provided with one Embodiment of the chemical heat storage apparatus which concerns on this invention. It is a front view of the structure containing the heat exchanger and reactor shown in FIG. FIG. 3 is a perspective view of the press-molded body shown in FIG. 2. It is a perspective view of the heat-transfer member shown in FIG. It is sectional drawing which shows the method of producing the press molding shown in FIG. 2 by press molding. It is sectional drawing which shows the ideal example and actual example of a press molding which has the structure where the heat-transfer member stood along the press direction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic configuration diagram showing an exhaust purification system including an embodiment of a chemical heat storage device according to the present invention. In the figure, an exhaust purification system 1 is provided in an exhaust system of a diesel engine 2 (hereinafter simply referred to as an engine 2) of a vehicle, and removes harmful substances (environmental pollutants) contained in exhaust gas discharged from the engine 2. It is a purification system.

  The exhaust purification system 1 includes a heat exchanger 4 provided in an exhaust pipe 3 connected to the engine 2, a diesel oxidation catalyst (DOC) 5, a diesel exhaust particulate filter (DPF) 6, A selective reduction catalyst (SCR: Selective Catalytic Reduction) 7 and an ammonia slip catalyst (ASC: Ammonia Slip Catalyst) 8 are provided. These heat exchangers 4, DOC5, DPF6, SCR7, and ASC8 are sequentially arranged from the exhaust upstream side to the exhaust downstream side.

  The heat exchanger 4 exchanges heat between exhaust gas flowing in the exhaust pipe 3 and a reactor 11 described later. As shown in FIG. 2, the heat exchanger 4 includes an outer cylinder 4a and a heat exchange member 4b disposed inside the outer cylinder 4a. The heat exchange member 4b has a honeycomb structure. The heat exchange member 4b is not particularly limited to a honeycomb structure, and a known heat exchange structure can be used.

The DOC 5 is a catalyst that oxidizes and purifies HC and CO contained in the exhaust gas. The DPF 6 is a filter that collects and removes particulate matter (PM) contained in the exhaust gas. The SCR 7 is a catalyst that reduces and purifies NOx contained in the exhaust gas with urea or ammonia (NH ₃ ). ASC8 is a catalyst for oxidizing the NH ₃ having passed through the SCR7.

  Further, the exhaust purification system 1 includes the chemical heat storage device 10 of the present embodiment. The chemical heat storage device 10 is a device that heats the heat exchanger 4 that is an object to be heated without energy by storing heat (exhaust heat) of the exhaust gas and using the exhaust heat when necessary. is there.

As shown in FIGS. 1 and 2, the chemical heat storage device 10 includes a reactor 11 disposed around the heat exchanger 4 outside the exhaust pipe 3, and the reactor 11 and the NH ₃ supply pipe 12. And an adsorber 13 connected to be able to circulate NH ₃ as a reaction medium. The NH ₃ supply pipe 12 is provided with a valve 14 for opening and closing a flow path between the reactor 11 and the adsorber 13.

The adsorber 13 includes an adsorbent 13a that can be held and desorbed by physical adsorption of NH ₃ . As the adsorbent 13a, any one of activated carbon, carbon black, mesoporous carbon, nanocarbon, zeolite and the like is used. The adsorber 13 is a reservoir that stores NH ₃ by physically adsorbing NH ₃ on the adsorbent 13a.

As shown in FIG. 2, the reactor 11 includes a ring-shaped case 15 provided so as to surround the exhaust pipe 3, and a press-molded body accommodated in the case 15 so as to contact the outer peripheral surface of the exhaust pipe 3. 16. An NH ₃ supply pipe 12 is connected to the case 15. Between the casing 15 and the press-molded body 16, although not shown, a porous sheet for conducting the entire periphery of NH ₃ supplied from the NH ₃ supply pipe 12 to the press-molded body 16 is arranged .

The press-molded body 16 has a ring shape by connecting a plurality of curved section-shaped press molded bodies 16A. As shown in FIG. 3, the press-molded body 16 </ b> A generates heat for chemically reacting with NH ₃ to heat the heat exchanger 4, and receives exhaust heat to store heat and desorb NH _3. The heat storage material part 17 which consists of a heat storage material of a shape, and the sheet-shaped L-shaped heat-transfer member 18 with a heat conductivity higher than this heat storage material are included. The press-molded body 16A (press-molded body 16) has a structure in which a plurality of such heat storage material portions 17 and heat transfer members 18 are alternately stacked.

  As the heat storage material, a material having a composition MXa of a halide is used. Here, M is an alkaline earth metal such as Mg, Ca, or Sr, or a transition metal such as Cr, Mn, Fe, Co, Ni, Cu, or Zn. X is Cl, Br, I or the like. a is 2-3. The heat transfer member 18 is made of a material having high thermal conductivity such as a metal such as aluminum or a graphite sheet.

  As shown in FIGS. 3 and 4, the heat transfer member 18 includes a main body portion 19 for transferring heat generated from the heat storage material portion 17 toward the heat exchanger 4, and an inner side (heat exchanger) of the main body portion 19. The auxiliary portion 20 is provided so as to be bent at a right angle with respect to the main body portion 19 at the end portion on the (4 side). The inner surface of the auxiliary portion 20 is in contact with the outer peripheral surface of the exhaust pipe 3.

  The main body 19 extends from the outer peripheral surface (the surface on the opposite side of the heat exchanger 4) of the press molded body 16A to the inner peripheral surface (the surface on the heat exchanger 4 side) of the press molded body 16A. The main surface (front surface and back surface) 19a of the main body 19 is a surface perpendicular to the pressing direction of the press-molded body 16A. The press direction of the press-molded body 16A is a direction in which the heat storage material is pressed when the press-molded body 16A is produced by press molding (described later).

The main body 19 is formed with a plurality of through holes 21 through which NH ₃ introduced from the NH ₃ supply pipe 12 into the heat storage material portion 17 is passed. The shape and dimensions of the through hole 21 are not particularly limited.

  For such a heat transfer member 18, for example, a single curved original plate is prepared, and a plurality of through holes 21 are formed in a region to be the main body portion 19 of the curved original plate. It is produced by bending it. Alternatively, the heat transfer member 18 may be manufactured by configuring the main body 19 and the auxiliary portion 20 as separate members and joining the auxiliary portion 20 to the main body 19 in which the plurality of through holes 21 are formed. In this case, the auxiliary unit 20 does not necessarily have to be a sheet.

  The press molded body 16A is manufactured by press molding using a mold. Specifically, as shown in FIG. 5, a lower mold 22 having a concave cavity 22a and an upper mold 23 to be inserted into the cavity 22a are prepared. Then, the heat transfer member 18 and the powdered heat storage material are put into the cavity 22a in order. At this time, the heat transfer member 18 is disposed in the cavity 22 a so that the auxiliary portion 20 contacts the inner surface of the lower mold 22 and the tip of the auxiliary portion 20 faces the upper side of the lower mold 22. In this state, the upper mold 23 is set in the cavity 22a, and the heat storage material is pressed simultaneously with the heat transfer member 18 by the upper mold 23, whereby the heat storage material is pressed and hardened. Thereby, the press molding 16A in which the heat-transfer member 18 and the pellet-shaped heat storage material part 17 are laminated | stacked alternately is obtained.

In such a chemical heat storage device 10, when the temperature of the exhaust gas discharged from the engine 2 is low, NH ₃ is passed from the adsorber 13 to the reactor 11 through the NH ₃ supply pipe 12 by opening the valve 14. The heat storage material (for example, MgCl ₂ ) and NH ₃ that are supplied and form the heat storage material portion 17 of the reactor 11 chemically react and chemically adsorb (coordinate bond), and heat is generated from the heat storage material portion 17. That is, a reaction from the left side to the right side (exothermic reaction) in the following reaction formula (A) occurs. Then, the heat generated from the heat storage material portion 17 is transmitted to the heat exchanger 4 through the exhaust pipe 3. At this time, the heat generated from the heat storage material portion 17 reaches the heat transfer member 18, and the heat is transferred to the exhaust pipe 3 and the heat exchanger 4 through the heat transfer member 18. Thereby, the heat exchanger 4 is heated, and the exhaust gas flowing through the heat exchanger 4 is heated accordingly.
_{MgCl 2 + x NH 3 ⇔ Mg} (NH 3) x Cl 2 + heat ... (A)

On the other hand, when the temperature of the exhaust gas discharged from the engine 2 increases, the heat (exhaust heat) of the exhaust gas is given to the heat storage material part 17 of the reactor 11 through the exhaust pipe 3, thereby The heat storage material to be formed and NH ₃ are separated. That is, a reaction (regeneration reaction) from the right side to the left side in the above reaction formula (A) occurs. At this time, the exhaust heat is transmitted to the heat storage material portion 17 through the heat transfer member 18. Then, NH ₃ desorbed from the heat storage material returns to the adsorber 13 through the NH ₃ supply pipe 12 and is physically adsorbed (recovered) by the adsorbent 13 a of the adsorber 13.

As described above, in the present embodiment, the reactor 11 includes the press-molded body 16 including the heat storage material portion 17 made of the heat storage material and the heat transfer member 18 having a higher thermal conductivity than the heat storage material, The heat transfer member 18 has a main body 19 for transmitting heat generated by a chemical reaction between the heat storage material and NH ₃ toward the inside of the press-molded body 16 (on the heat exchanger 4 side). Thereby, the thermal conductivity of the press-molded body 16 of the reactor 11 can be increased.

  By the way, for example, as shown in FIG. 6A, it is conceivable that the heat transfer member 51 has a structure standing along the pressing direction of the press-molded body 50. However, the following problems occur in such a structure. That is, when a powdery heat storage material is pressed simultaneously with the heat transfer member 51 using a mold, the heat transfer member 51 is actually crushed as shown in FIG. For this reason, since the heat transfer member 51 does not extend to the outer peripheral surface of the press-molded body 50, the heat generated from the region on the outer peripheral surface side of the press-molded body 50 in the heat storage material portion 17 reaches the heat transfer member 51. It becomes difficult, and the high thermal conductivity of the press-molded body 50 cannot be ensured.

  On the other hand, in the present embodiment, the main surface 19 a of the main body 19 of the heat transfer member 18 is a surface perpendicular to the press direction of the press-molded body 16. That is, when the press-molded body 16 </ b> A is manufactured by press molding, the main surface 19 a of the main body 19 is pressed together with the heat storage material 17. Thereby, it is prevented that the main-body part 19 is crushed at the time of press molding. The auxiliary portion 20 of the heat transfer member 18 stands along the pressing direction of the press-molded body 16. However, the press molding process is performed in a state where the auxiliary portion 20 is in contact with the inner surface of the lower mold 22 forming the cavity 22a as described above. For this reason, the auxiliary | assistant part 20 is hard to be crushed at the time of a press molding process.

  As described above, since the heat transfer member 18 is prevented from being crushed when the press-molded body 16A is manufactured, high thermal conductivity of the press-molded body 16 can be ensured. For example, the effective thermal conductivity of the press-molded body 16 can be set to about 40 W / m · K, for example. When the heat transfer member 18 is not provided in the press-molded body 16, the effective thermal conductivity of the press-molded body 16 is, for example, 1 W / m · K or less. Therefore, the chemical heat storage device 10 having a high heat output can be obtained.

Thereby, at the time of exothermic reaction, the heat generated from the heat storage material portion 17 of the reactor 11 can be efficiently transmitted to the heat exchanger 4. As a result, the heat exchanger 4 can be efficiently heated, and the exhaust gas can be efficiently heated. On the other hand, during the regeneration reaction, the heat of the exhaust gas can be efficiently transmitted to the heat storage material portion 17. As a result, the NH ₃ regeneration speed can be increased.

  Further, since the heat transfer member 18 includes the auxiliary portion 20 provided to bend with respect to the main body portion 19, the contact area of the heat transfer member 18 with respect to the exhaust pipe 3 is increased. Therefore, the heat generated from the heat storage material portion 17 can be transmitted to the heat exchanger 4 more efficiently.

  Furthermore, since the press-molded body 16 has a structure in which a plurality of the heat storage material portions 17 and the heat transfer members 18 are alternately stacked, the position of the heat storage material portion 17 farthest from the heat transfer member 18 and the heat transfer member 18. The distance between is shortened. Therefore, since the heat generated from the heat storage material part 17 can easily reach the heat transfer member 18, the heat generated from the heat storage material part 17 can be transmitted to the heat exchanger 4 more efficiently.

Further, the main body portion 19 of the heat transfer member 18, since a plurality of through holes 21 for the passage of NH _3, NH ₃ introduced into the heat storage material 17 from the NH ₃ supply pipe 12 through holes 21 It moves through the heat storage material part 17 through. Therefore, NH ₃ can be rapidly supplied to most of the heat storage material portion 17. Thereby, heat can be effectively generated from the heat storage material portion 17.

  In addition, this invention is not limited to the said embodiment. For example, in the above embodiment, the main body portion 19 of the heat transfer member 18 extends from the inner peripheral surface of the press-molded body 16 to the outer peripheral surface. It does not need to extend to an outer peripheral surface.

  Moreover, in the said embodiment, although the heat-transfer member 18 has the auxiliary | assistant part 20 provided so that it might bend with respect to the main-body part 19, the heat generated from the heat storage material part 17 of the reactor 11 is heat-exchanged. As long as it can be transmitted to the container 4, such an auxiliary unit 20 may be omitted.

  In the above embodiment, the press-molded body 16 </ b> A has a plurality of heat transfer members 18, but heat generated from the heat storage material portion 17 of the reactor 11 can be transmitted to the heat exchanger 4. In this case, the number of heat transfer members 18 included in the press-molded body 16A may be one.

Furthermore, in the above embodiment, the main body portion 19 of the heat transfer member 18, a plurality of through holes 21 for passing the NH ₃ is formed, to supply the NH ₃ to the majority of the heat storage material 17 If possible, such a through hole 21 may not be particularly provided.

  Moreover, in the said embodiment, although the reactor 11 is arrange | positioned around the heat exchanger 4 in the outer side of the exhaust pipe 3, as an arrangement | positioning location of the reactor 11, it is not restricted to it in particular, The heat exchanger 4 It may be inside the exhaust pipe 3 as long as it is around.

  In the above embodiment, only one heat exchanger 4 is arranged inside the exhaust pipe 3, but the number of heat exchangers is not particularly limited to one, and is viewed from the direction in which the exhaust gas flows. A plurality of heat exchangers may be arranged inside the exhaust pipe 3. In this case, the reactor is integrally provided around each heat exchanger in the exhaust pipe 3.

Furthermore, in the above embodiment, NH ₃ which is a gaseous reaction medium and heat storage material having a composition of MXa are chemically reacted to generate heat. However, the reaction medium is not particularly limited to NH _3. For example, CO ₂ or H ₂ O may be used. When CO ₂ is used as a reaction medium, the heat storage material that chemically reacts with CO ₂ includes MgO, CaO, BaO, Ca (OH) ₂ , Mg (OH) ₂ , Fe (OH) ₂ , and Fe (OH) _3. FeO, Fe ₂ O ₃ , Fe ₃ O _{4 and the} like can be used. When H ₂ O is used as the reaction medium, CaO, MnO, CuO, Al ₂ O ₃ or the like can be used as the heat storage material that chemically reacts with H ₂ O.

  Moreover, in the said embodiment, although the heat exchanger 4 is heated with the chemical thermal storage apparatus 10, this invention is what heats catalysts, such as DOC5 provided in the exhaust system of the diesel engine 2, in the exhaust pipe 3. The present invention is also applicable to one that heats a region where the heat exchanger 4 or the DOC 5 or the like is not provided, or one that heats any catalyst or the like provided in an exhaust system of a gasoline engine. Furthermore, the present invention can be applied to other than an engine exhaust system, for example, one that heats piping or the like provided in an oil circulation system.

4 ... Heat exchanger (object to be heated), 10 ... Chemical heat storage device, 11 ... Reactor, 13 ... Adsorber (storage), 16, 16A ... Press-molded body, 17 ... Heat storage material part, 18 ... Heat transfer member , 19 ... body part, 19a ... main surface, 20 ... auxiliary part, 21 ... through hole.

Claims (4)

In a chemical heat storage device that heats an object to be heated,
A heat storage material portion made of a heat storage material that is arranged around the heating object and generates a heat by chemically reacting with the reaction medium and desorbs the reaction medium and has a higher thermal conductivity than the heat storage material. A reactor having a press-molded body including a heat transfer member;
A reservoir for connecting the reaction medium and the reaction medium so as to be able to flow therethrough, and storing the reaction medium;
The heat transfer member has a sheet-like main body portion for transmitting heat generated from the heat storage material portion toward the heating object,
The main surface of the main body is a surface perpendicular to the pressing direction of the press-molded body.   2. The chemical heat storage device according to claim 1, wherein the heat transfer member further includes an auxiliary portion provided to bend with respect to the main body at an end of the main body on the heating object side. .   The chemical heat storage device according to claim 1 or 2, wherein the press-molded body is formed by alternately laminating a plurality of the heat storage material portions and the heat transfer members. The chemical heat storage device according to claim 1, wherein a plurality of through holes through which the reaction medium passes are formed in the main body portion.

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