JP2016044906A - Chemical heat storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chemical heat storage device capable of efficiently transmitting heat generated by a reaction material in a reactor to a heating object.SOLUTION: A chemical heat storage device includes a heat exchanger 3 with a reactor having a reaction part 15 and a plurality of heat exchange members 16, and an adsorber connected so that NHcan flow between the reaction part 15 and it. The reaction part 15 is stored in the reactor 17, and has a reaction material 18 generating heat through a chemical reaction with NHand desorbing NHby stored heat of exhaust heat. The heat exchange member 16 has a heat exchange part 21 forming an exhaust gas flow passage 21a through which exhaust gas flows from one end side to the other end side and performing heat exchange between the exhaust gas and the reaction material 18, and a cylindrical heat exchange part outer cylinder 20 provided on an outer periphery of the heat exchange part 21. The heat exchange members 16 are buried in the reaction material 18 along a direction perpendicular to a flow direction of the exhaust gas in the inside of the reactor 17.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a chemical heat storage device.

  As a conventional chemical heat storage device, for example, a device described in Patent Document 1 is known. A chemical heat storage device described in Patent Document 1 is disposed around a catalyst ceramic portion that purifies exhaust gas discharged from an engine, and includes a reactor including a heat storage material (reaction material) built in a housing portion, and a heat storage And a water conduit for supplying water for generating heat from the substance. By supplying water to the reactor, such as when it is cold, the water and the heat storage material chemically react to generate heat. The catalyst ceramic portion is heated by the heat generated in the reactor and warmed to the catalyst activation temperature.

JP 59-208118 A

  However, in the above prior art, the reactor that is the heating source is arranged around the catalyst ceramic portion that is the heating object. Therefore, for example, when the diameter of the catalyst ceramic part is increased in order to improve the exhaust gas purification capacity, the heat transfer distance from the outer periphery of the catalyst ceramic part to the center of the catalyst ceramic part becomes long, and the thermal resistance of the catalyst ceramic part increases. For this reason, it becomes difficult for the heat generated in the reactor on the outer periphery of the catalyst ceramic portion to be transmitted to the center of the catalyst ceramic portion. That is, in the conventional configuration, it is difficult to efficiently transfer the heat generated by the heat storage material (reaction material) in the reactor to the catalyst ceramic part that is the object to be heated.

  An object of the present invention is to provide a chemical heat storage device that can efficiently transfer heat generated by a reaction material in a reactor to an object to be heated.

  The present invention relates to a chemical heat storage device for heating a heat medium, wherein a reaction part which is heated in a reaction vessel and is filled with a reaction material that generates heat and desorbs the reaction medium by heat storage, and a reaction part And a storage section that stores the reaction medium and a plurality of heat exchange members that circulate the heat medium, and the heat exchange member heats from one end side to the other end side. A heat exchanger that forms a heat medium flow path for circulating the medium and exchanges heat between the heat medium and the reaction material, and a cylindrical heat that is provided on the outer periphery of the heat exchanger and extends in the flow direction of the heat medium The plurality of heat exchanging members are embedded in the reaction material side by side in a direction perpendicular to the flow direction of the heat medium inside the reaction vessel.

  In such a chemical heat storage device of the present invention, when the reaction medium is supplied from the storage unit to the reaction unit, the reaction material generates heat due to a chemical reaction between the reaction material and the reaction medium, and the heat is generated by each heat exchange member. It is transmitted to the heat exchange section. At this time, the plurality of heat exchange members are embedded in the reaction material in a direction perpendicular to the flow direction of the heat medium in the reaction vessel, thereby being perpendicular to the flow direction of the heat medium in the heat exchange portion of each heat exchange member. The dimension in a proper direction can be reduced. When the dimension in the direction perpendicular to the flow direction of the heat medium in the heat exchange part of each heat exchange member is reduced, the heat transfer distance from the outer periphery of the heat exchange part where the heating source is arranged to the center of the heat exchange part is shortened, The heat resistance of the heat exchange part is reduced. For this reason, the heat generated by the reaction material arranged on the outer periphery of the heat exchange part is easily transmitted to the center of the heat exchange part. That is, in the present invention, the heat generated by the reaction material in the reactor can be efficiently transferred to the heat exchanging part that is the object to be heated.

  The plurality of heat exchange members may be arranged apart from each other so that the entire circumference of each outer tube of the heat exchange section is in contact with the reaction material. In this case, the heat generated in the reaction material is transmitted from the entire outer periphery of the heat exchange unit toward the center of the heat exchange unit. Therefore, the heat generated in the reaction material can be more efficiently transmitted to the heat exchange unit.

  The reaction part may further have a heat insulating material provided between the reaction vessel and the reaction material. In this case, the heat generated in the reaction material can be reduced from being radiated to the outside from the reaction vessel.

  The reaction unit may be disposed on a heat medium flow path through which the heat medium is circulated, and the reaction container may have a plurality of openings that expose both end portions of the plurality of heat exchange members. In this case, a plurality of heat exchange members can be easily embedded in the reaction material.

  ADVANTAGE OF THE INVENTION According to this invention, the chemical heat storage apparatus which can transmit efficiently the heat | fever generated with the reaction material in a reactor to a heating target object is provided.

It is a schematic block diagram which shows the exhaust gas purification system provided with one Embodiment of the chemical heat storage apparatus. It is a schematic block diagram of the chemical heat storage apparatus which has the side view (a partial cross section is included) of the heat exchanger with a reactor shown by FIG. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG.

  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 illustrating an exhaust purification system including an embodiment of a chemical heat storage device. In FIG. 1, 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 purifies harmful substances (environmental pollutants) contained in exhaust gas discharged from the engine 2. To do.

  The exhaust purification system 1 includes a heat exchanger 3 with a reactor, a diesel oxidation catalyst (DOC) 4, a diesel exhaust particulate filter (DPF) 5, a selective catalytic catalyst (SCR) 6 And an ammonia slip catalyst (ASC) 7. The reactor-equipped heat exchanger 3, DOC 4, DPF 5, SCR 6, and ASC 7 are arranged in order from the upstream side toward the downstream side in the exhaust passage 8 connected to the engine 2.

The heat exchanger with a reactor 3 will be described in detail later. The DOC 4 oxidizes and purifies HC and CO contained in the exhaust gas. The DPF 5 collects particulate matter (PM) contained in the exhaust gas and removes PM from the exhaust gas. The SCR 6 reduces and purifies NOx contained in the exhaust gas with urea or ammonia (NH ₃ ). ASC7 oxidizes NH ₃ passing through the SCR6.

Further, the exhaust purification system 1 includes a chemical heat storage device 10 that heats (warms up) a heating object such as a heat exchanger without using external energy by using a reversible chemical reaction. Specifically, the chemical heat storage device 10 stores the heat (exhaust heat) of the exhaust gas in the chemical heat storage device 10 by separating a reaction material 18 and a reaction medium described later from each other. The chemical heat storage device 10 supplies the reaction medium to the reaction material 18 when necessary, causes the reaction material 18 and the reaction medium to chemically react (chemical adsorption), and heats using the reaction heat during the chemical reaction. Heat the object. In this embodiment, NH ₃ (ammonia) is used as the reaction medium.

As shown in FIG. 2, the chemical heat storage device 10 includes the heat exchanger 3 with a reactor, a reaction unit 15 (described later) of the heat exchanger 3 with a reactor, and an NH ₃ supply pipe 11. And an adsorber 12 connected to be able to circulate NH ₃ . The NH ₃ supply pipe 11 is provided with an on-off valve 13 for opening and closing a flow path between the reaction unit 15 and the adsorber 12 of the heat exchanger 3 with a reactor.

The adsorber 12 includes an adsorbent 14 that can hold and desorb NH ₃ as a reaction medium by physical adsorption. As the adsorbent 14, activated carbon, carbon black, mesoporous carbon, nanocarbon, zeolite, or the like is used. The adsorber 12 forms a storage unit that stores NH ₃ by physically adsorbing NH ₃ on the adsorbent 14.

As shown in FIGS. 2 to 4, the reactor-equipped heat exchanger 3 is disposed adjacent to the reaction unit 15 and the reaction unit 15 in a direction perpendicular to the flow direction of the exhaust gas that is a heat medium. And a plurality of (in this case, four) heat exchange members 16. The NH ₃ supply pipe 11 is connected to the reaction unit 15.

The reaction unit 15 is disposed on an exhaust gas distribution path A (heat medium distribution path) through which exhaust gas that is a heat medium flows. The reaction unit 15 includes a reaction vessel 17, is charged to the reaction vessel 17, the NH ₃ and a reaction member 18 that is eliminated by the heat storage of waste heat while heat by chemical reaction with NH _3.

  The reaction vessel 17 includes a cylindrical outer cylinder portion 17a and a pair of circular lid portions 17b fixed to the upstream end portion and the downstream end portion of the outer cylinder portion 17a. Each lid portion 17b is formed with a plurality of openings 17c that expose both end portions of the plurality of heat exchange members 16. The reaction vessel 17 is made of a metal such as stainless steel.

  As the reaction material 18, a halide represented by the composition formula MXa is used. 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 a number specified by the valence of M, and is 2-3.

  The reaction material 18 may be in the form of a powder or a press-molded body. The reaction material 18 may be mixed with an additive for improving thermal conductivity. As the additive, carbon fiber, carbon bead, SiC bead, metal bead, polymer bead, polymer fiber or the like is used. Examples of the metal material of the metal beads include Cu, Ag, Ni, Ci—Cr, Al, Fe, and stainless steel.

Between the reaction vessel 17 and the reaction material 18, a heat insulating material 19 is arranged in an annular shape. For example, glass wool or the like is used as the heat insulating material 19. By providing the heat insulating material 19, heat generated in the reaction material 18 is suppressed from being radiated to the outside from the reaction container 17. One end of the NH ₃ supply pipe 11 penetrates the heat insulating material 19 and is connected to the reaction material 18. A porous body (not shown) that forms a NH ₃ flow path is interposed between the reaction material 18 and the heat insulating material 19.

The heat exchange member 16 includes a heat exchange part 21 having a honeycomb structure and a cylindrical heat exchange part outer cylinder 20 provided on the outer periphery of the heat exchange part 21 and extending in the flow direction of the exhaust gas. The heat exchanging unit 21 forms an exhaust gas passage 21 a (heat medium passage) through which exhaust gas flows from one end side to the other end side, and performs heat exchange between the exhaust gas and the reactant 18. The heat exchange portion outer cylinder 20 is formed of stainless steel or the like having corrosion resistance against NH ₃ . The heat exchanging portion 21 is made of ceramic such as SiSiC having high thermal conductivity.

  Each heat exchange member 16 is accommodated in a reaction container 17 of the reaction unit 15. Specifically, the heat exchange members 16 are embedded in the reaction material 18 side by side in the direction perpendicular to the flow direction of the exhaust gas inside the reaction vessel 17. At this time, the heat exchange members 16 are arranged so as to be separated from each other so that the entire circumference of the heat exchange portion outer cylinder 20 is in contact with the reaction material 18. Thereby, the reaction material 18 is arrange | positioned in the whole circumference | surroundings of each heat exchange member 16. FIG.

In the exhaust purification system 1 including the chemical heat storage device 10 as described above, the open / close valve 13 is opened when the temperature of the exhaust gas discharged from the engine 2 is lower than a predetermined temperature. Then, NH ₃ desorbed from the adsorbent 14 of the adsorber 12 due to the pressure difference between the adsorber 12 and the reaction unit 15 is supplied to the reaction unit 15 through the NH ₃ supply pipe 11. Then, the reaction material 18 (for example, MgCl ₂ ) and NH ₃ in the reaction unit 15 chemically react and chemically adsorb, and heat is generated from the reaction material 18. 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 reaction material 18 is transmitted to each heat exchange member 16. Thereby, each heat exchange member 16 is heated, and the exhaust gas which flows through the heat exchange part 21 of each heat exchange member 16 is heated in connection with this. That is, the exhaust gas is heat-exchanged by each heat exchange member 16 and heated. Then, the heated exhaust gas raises the DOC 4 to an activation temperature suitable for purification of pollutants.
_{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 becomes equal to or higher than a predetermined temperature, the heat (exhaust heat) of the exhaust gas is given to the reaction material 18 of the reaction unit 15, whereby NH ₃ is desorbed from the reaction material 18. To do. That is, a reaction (regeneration reaction) from the right side to the left side in the above reaction formula (A) occurs. Then, due to the pressure difference between the reaction unit 15 and the adsorber 12, NH ₃ desorbed from the reaction material 18 returns to the adsorber 12 through the NH ₃ supply pipe 11, and NH ₃ is adsorbed on the adsorbent 14 of the adsorber 12. Physically adsorbed. Thereby, NH ₃ is recovered in the adsorber 12.

  As described above, in the present embodiment, the reaction material 17 is filled in the reaction vessel 17 of the reaction unit 15, and the plurality of heat exchange members 16 are arranged in the reaction vessel 17 in a direction perpendicular to the flow direction of the exhaust gas. Embedded in the reaction material 18 side by side, the outer diameter of each heat exchange member 16 (circulation of exhaust gas) compared to the case where the reaction material is arranged in an annular shape around one heat exchange member. Dimension in a direction perpendicular to the direction) can be reduced. Thus, when the outer diameter of the heat exchange part 21 becomes small, the distance (heat transfer distance) between the outer periphery and the center in the heat exchange part 21 becomes short, and the heat resistance of the heat exchange part 21 becomes small.

  Therefore, during the exothermic reaction, the heat generated in the reaction material 18 is easily transmitted to the center of the heat exchange unit 21. Thereby, the heat generated in the reaction material 18 can be efficiently transmitted to the heat exchange unit 21. As a result, the exhaust gas can be efficiently heated to the optimum temperature.

Further, during the regeneration reaction, the heat of the exhaust gas passing through the central portion of the heat exchange part 21 of each heat exchange member 16 is easily transmitted to the reaction material 18 of the reaction part 15. Thereby, NH ₃ can be efficiently desorbed from the reaction material 18 by the heat of the exhaust gas. As a result, the recovery of NH ₃ to the adsorber 12 can be performed efficiently.

  Furthermore, since the heat exchange members 16 are arranged so as to be separated from each other so that the entire circumference of the heat exchange portion outer cylinder 20 is in contact with the reaction material 18, as described above, the reaction material is entirely disposed around the heat exchange members 16. 18 will be arranged.

For this reason, at the time of exothermic reaction, the heat generated in the reaction material 18 is transmitted from the entire outer periphery of the heat exchange part 21 of each heat exchange member 16 toward the center of the heat exchange part 21. Therefore, since the heat exchange portion 21 of each heat exchange member 16 is heated from the entire outer periphery by the heat generated in the reaction material 18, the exhaust gas can be heated more efficiently. Further, during the regeneration reaction, the heat of the exhaust gas passing through the heat exchanging portion 21 of each heat exchange member 16 is efficiently given to the reaction material 18, so that the recovery of NH ₃ to the adsorber 12 can be performed more efficiently. .

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the plurality of heat exchanging members 16 are arranged apart from each other so that the entire circumference of the heat exchanging portion outer cylinder 20 is in contact with the reaction material 18. You may arrange | position so that the heat exchange member 16 of this may be contacted. In this case, since the outer diameter of the reaction vessel 17 of the reaction unit 15 can be reduced, the size of the reactor-equipped heat exchanger 3 can be reduced.

  Moreover, in the said embodiment, although the outer cylinder part 17a of the reaction container 17 of the reaction part 15 is cylindrical, and the heat exchange part outer cylinder 20 of each heat exchange member 16 is cylindrical, it is not restricted to it in particular, For example, both the outer cylinder part 17a and the heat exchange part outer cylinder 20 may be rectangular cylinders, or either one of the outer cylinder part 17a and the heat exchange part outer cylinder 20 is cylindrical and the other is a rectangular cylinder. It may be.

  Furthermore, in the said embodiment, although the heat exchange part 21 of the heat exchange member 16 is formed with the ceramic, it is not restricted to it in particular as a material of the heat exchange part 21, It is metal, such as stainless steel with high heat conductivity. There may be. Further, a catalyst may be supported on the heat exchange part 21 of the heat exchange member 16.

Furthermore, in the above embodiment, the reaction medium NH ₃ and the reaction material 18 represented by the composition formula MXa are chemically reacted to generate heat, but 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 the reaction medium, the reaction 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 or Fe ₃ O ₄ can be used. When H ₂ O is used as a reaction medium, CaO, MnO, CuO, Al ₂ O ₃ or the like can be used as a reaction material that chemically reacts with H ₂ O.

  Moreover, although the chemical heat storage apparatus 10 of the said embodiment is provided in the exhaust system of the diesel engine 2, this invention is provided in addition to the chemical heat storage apparatus provided in the exhaust system of the gasoline engine, or the engine exhaust system. The present invention can also be applied to chemical heat storage devices.

  DESCRIPTION OF SYMBOLS 10 ... Chemical heat storage apparatus, 12 ... Adsorber (storage part), 15 ... Reaction part, 16 ... Heat exchange member, 17 ... Reaction container, 17c ... Opening part, 18 ... Reaction material, 19 ... Heat insulation material, 20 ... Heat exchange Part outer cylinder, 21 ... heat exchange part, 21a ... exhaust gas flow path (heat medium flow path), A ... exhaust gas flow path (heat medium flow path).

Claims (4)

A chemical heat storage device for heating a heat medium,
A reaction section in which a reaction material that generates heat and desorbs the reaction medium by storing heat is filled in a reaction vessel with a chemical reaction with the reaction medium;
A storage unit that is connected to the reaction unit so that the reaction medium can flow therethrough, and stores the reaction medium;
A plurality of heat exchange members for circulating the heat medium,
The heat exchange member forms a heat medium flow path through which the heat medium flows from one end side to the other end side, and performs heat exchange between the heat medium and the reaction material, and the heat exchange A cylindrical heat exchange portion outer cylinder provided on the outer periphery of the portion and extending in the flow direction of the heat medium;
The chemical heat storage device, wherein the plurality of heat exchange members are embedded in the reaction material side by side in a direction perpendicular to a flow direction of the heat medium inside the reaction vessel.   2. The chemical heat storage device according to claim 1, wherein the plurality of heat exchange members are spaced apart from each other such that the entire circumference of each of the heat exchange portion outer cylinders is in contact with the reaction material.   The chemical heat storage device according to claim 1, wherein the reaction unit further includes a heat insulating material provided between the reaction container and the reaction material. The reaction unit is disposed on a heat medium flow path for flowing the heat medium,
4. The chemical heat storage device according to claim 1, wherein the reaction container has a plurality of openings that expose both end portions of the plurality of heat exchange members. 5.

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