JP2016196969A - Chemical heat storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately prevent an abnormal overpressure state within a reactor and a storage unit.SOLUTION: A chemical heat storage device 10 includes: a heater 11 having a reaction material 13; a storage 12 for storing NH; a supply pipe 15 that communicates the heater 11 with the storage 12 to make NHflow between the heater 11 and the storage 12; a valve 16 arranged in the supply pipe 15 to open/close a flow passage of NHbetween the heater 11 and the storage 12; reactor pressure control means 19 for making NHin the heater 11 flow in one direction from the heater 11 to the storage 12 when the pressure in the heater 11 reaches preset first set pressure or larger with the valve 16 closed; and storage unit pressure control means 22 for discharging NHin the storage 12 to outside of a reaction system when the pressure in the storage 12 reaches preset second set pressure or larger with the valve 16 closed. The second set pressure is larger than the first set pressure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a chemical heat storage device.

  As a conventional chemical heat storage device, a chemical heat storage device applied to an exhaust gas purification system that purifies exhaust gas discharged from an internal combustion engine of a vehicle is known (for example, see Patent Document 1). In the chemical heat storage device applied to the exhaust gas purification system, when the temperature of the exhaust gas discharged from the internal combustion engine falls below the warm-up start temperature, the on-off valve provided in the supply pipe is opened and stored in the reservoir The reaction medium is fed to the reactor through a feed tube. As a result, the supplied reaction medium and the reaction material of the reactor react chemically to generate heat, and the heating target such as a heat exchanger is heated by the generated heat. Further, when the temperature of the exhaust gas discharged from the internal combustion engine becomes higher than the reaction medium regeneration temperature, the heat of the exhaust gas is given to the reaction material in the reactor, and the reaction medium is desorbed from the reaction material in the reactor. Then, the desorbed reaction medium is collected in the reservoir through the supply pipe. Thereafter, the on-off valve is closed.

JP 2013-72558 A

  In the conventional chemical heat storage device, the inside of the reactor may be in an overpressure state. For example, when the reaction medium is recovered, the reactor is in a high temperature state. If the on-off valve is closed due to the engine being stopped at this time, the reaction medium cannot move from the reactor to the reservoir. The medium is full and the reactor is in an abnormal overpressure condition. If the reactor is in an abnormal overpressure state, the reactor may burst.

  Moreover, in the said conventional chemical heat storage apparatus, the inside of a storage device may be in an overpressure state. For example, the temperature of the reservoir varies depending on the outside air temperature, but when the outside air temperature rises and the reservoir becomes hot when the on-off valve is closed, the reaction medium cannot move from the reservoir to the reactor. The reservoir is filled with the reaction medium, and the reservoir is in an abnormal overpressure state. If the reservoir is in an abnormal overpressure condition, the reservoir may rupture.

  An object of this invention is to provide the chemical heat storage apparatus which can prevent appropriately the abnormal overpressure state inside a reactor and a storage device.

  The chemical heat storage device according to the present invention is a chemical heat storage device that heats an object to be heated, and generates heat by a chemical reaction with the reaction medium when the reaction medium is supplied, and absorbs heat to desorb the reaction medium when heated. A reactor having a reaction material, a reservoir for storing the reaction medium, a connection pipe for communicating the reaction medium with the reactor, and a connection pipe for passing the reaction medium between the reactor and the reservoir; A first valve that opens and closes the flow path of the reaction medium between the reactor and the reservoir, and when the first valve is closed and the internal pressure of the reactor is equal to or higher than a preset first set pressure, Reactor pressure control means for causing the reaction medium in the reactor to flow in one direction from the reactor to the reservoir, and when the first valve is closed and the internal pressure of the reservoir is equal to or higher than a preset second set pressure The reaction medium in the reservoir, including the reactor, the reservoir and the connecting pipe. Comprising a reservoir pressure control means for discharging the reaction system outside of the second set pressure is larger than the first set pressure.

  In the chemical heat storage device according to the present invention, even when the first valve that opens and closes the flow path of the reaction medium between the reactor and the reservoir is closed, when the internal pressure of the reactor is equal to or higher than the first set pressure, The reaction medium moves in one direction from the reactor to the reservoir by the reactor pressure control means. Thereby, the abnormal overpressure state inside the reactor can be prevented. When the internal pressure of the reservoir becomes equal to or higher than the second set pressure, the reaction medium is discharged from the reservoir by the reservoir pressure control means, so that an abnormal overpressure state inside the reservoir can be prevented. Here, since the reactor is accompanied by a temperature change due to a chemical reaction, it is likely to be in an overpressure state as compared with the storage device. In the chemical heat storage device according to the present invention, when the internal pressure of the reactor rises to be equal to or higher than the first set pressure, the reaction medium in the reactor is converted into a reaction including the reactor, the reservoir, and the connecting pipe. It is prevented from being overpressured in the reactor by circulating in the reservoir and storing in the reservoir without discharging to the outside of the system. If the internal pressure of the reservoir rises to the second set pressure or higher, the reaction medium in the reservoir is discharged outside the reaction system without flowing through the reactor that is likely to be in an overpressure state. By doing so, the inside of the reservoir is prevented from being overpressured. Thereby, it is possible to prevent an abnormal overpressure state inside the reactor and the reservoir while reducing the possibility that the reaction medium is discharged to the outside of the reaction system. Furthermore, since the second set pressure is greater than the first set pressure, even if the internal pressure of the reactor becomes equal to or higher than the first set pressure and the reaction medium moves from the reactor to the reservoir, the internal pressure of the reservoir immediately It is possible to prevent the reaction medium in the reservoir from being discharged to the outside of the reaction system by reaching the two set pressures. As described above, an abnormal overpressure state inside the reactor and the reservoir can be appropriately prevented.

  In the chemical heat storage device according to the present invention, the reactor pressure control means includes a bypass pipe bypassing the first valve provided in the connection pipe, and a second valve provided in the bypass pipe, One valve and the second valve are configured as one unit. The second valve always shuts off the flow of the reaction medium from the reservoir side to the reactor side, and the pressure in the reactor is set to the first level. Closes when the pressure is less than the pressure, shuts off the flow of the reaction medium from the reactor side to the reservoir side, opens when the pressure in the reactor exceeds the first set pressure, and opens the reaction medium from the reactor side to the reservoir side. It may be distributed. In this case, since the first valve and the second valve arranged in the bypass pipe are unitized, an abnormal overpressure state in the reactor and the reservoir is appropriately prevented while preventing an increase in the size of the apparatus. Can be prevented.

  In the chemical heat storage device according to the present invention, the reactor is disposed in the exhaust system of the engine, the object to be heated is exhaust gas discharged from the engine, and the reservoir pressure control means includes a reservoir, an exhaust system, And a third valve disposed in the discharge pipe, the third valve is closed when the pressure in the reservoir is lower than the second set pressure, and the exhaust system from the reservoir side The reaction medium may be circulated from the reservoir side to the exhaust system when the pressure of the reaction medium is blocked and the pressure in the reservoir becomes equal to or higher than the second set pressure. In this case, when the pressure in the reservoir becomes the second set pressure or higher, the reaction medium is circulated from the reservoir side to the exhaust system through the discharge pipe by the third valve. Can be discharged into the system.

  ADVANTAGE OF THE INVENTION According to this invention, the chemical heat storage apparatus which can prevent appropriately the abnormal overpressure state inside a reactor and a storage is provided.

It is a schematic block diagram which shows the exhaust gas purification system provided with the chemical heat storage apparatus which concerns on one Embodiment of this invention. It is a conceptual diagram which shows operation | movement of the chemical heat storage apparatus shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  With reference to FIG. 1, the exhaust gas purification system provided with the chemical heat storage apparatus which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a schematic configuration diagram showing an exhaust gas purification system including a chemical heat storage device according to an embodiment of the present invention.

  An exhaust gas purification system 1 is disposed in an exhaust system of a diesel engine 2 (hereinafter simply referred to as an engine 2) that is an internal combustion engine of a vehicle, and contains harmful substances (environmental pollutants) contained in exhaust gas discharged from the engine 2 ) Purify. An exhaust gas purification system 1 includes a heat exchanger 4 and an oxidation catalyst (DOC: Diesel Oxidation Catalyst) 5 arranged in order from an upstream side to a downstream side in an exhaust pipe 3 that is an exhaust passage connected to an engine 2. , A diesel exhaust particulate filter (DPF) 6, a selective catalytic reduction (SCR) 7, and an oxidation catalyst (ASC: Ammonia Slip Catalyst) 8.

The heat exchanger 4 transfers heat between the exhaust gas from the engine 2 and a reaction material 13 described later. The heat exchanger 4 has a honeycomb structure, for example. The DOC 5 oxidizes and purifies HC and CO contained in the exhaust gas. The DPF 6 collects and removes particulate matter (PM) contained in the exhaust gas. The SCR 7 reduces and purifies NOx contained in the exhaust gas with urea or ammonia (NH ₃ ). The ASC 8 oxidizes and purifies NH ₃ that has passed through the SCR 7 and has flowed downstream of the SCR 7.

  Each catalyst of DOC5, SCR7, and ASC8 has a temperature range that can exhibit the ability to purify environmental pollutants, that is, an activation temperature. However, immediately after the start of the engine 2 or the like, the temperature of the exhaust gas immediately after being discharged from the engine 2 is relatively low, about 100 ° C., and may be lower than the activation temperature of each catalyst. Even in such a case, it is necessary to quickly bring the temperature at each catalyst to the activation temperature in order to exhibit the purification ability of each catalyst.

  Therefore, the exhaust gas purification system 1 includes a chemical heat storage device 10 for heating and heating the heat exchanger 4 disposed on the most upstream side of the exhaust pipe 3. By heating the heat exchanger 4, the exhaust gas heated through the heat exchanger 4 and having a raised temperature flows downstream of the heat exchanger 4.

The chemical heat storage device 10 heats the heat exchanger 4 to be heated without using external energy by using a reversible chemical reaction using NH ₃ as a reaction medium. That is, the chemical heat storage device 10 normally stores heat in the reaction material 13 by separating the reaction material 13 and the reaction medium described later, and when the heat exchanger 4 needs to be heated, By supplying the reaction medium to the reaction material 13, heat is generated from the reaction material 13 to heat the heat exchanger 4.

  The chemical heat storage device 10 includes a heater 11 (reactor), a storage 12 (reservoir), a supply pipe 15 (connection pipe), a valve 16 (first valve), a reactor pressure control means 19, and a reservoir. Pressure control means 22.

  The heater 11 is disposed around the exhaust pipe 3 so as to correspond to the heat exchanger 4 in the exhaust pipe 3. That is, the heater 11 is disposed so as to heat the heat exchanger 4. The heater 11 has, for example, an annular cross section surrounding the exhaust pipe 3. The cross-section of the annular cross section is a surface obtained by cutting the heater 11 perpendicular to the exhaust gas flow direction in the exhaust pipe 3.

The heater 11 has a reaction material 13 that chemically reacts with NH _{3 as} a reaction medium to generate heat, and accumulates heat to desorb NH ₃ by being heated by the heat of the exhaust gas. Therefore, in the heater 11, when NH ₃ is supplied from the storage 12, the NH ₃ and the reaction material 13 chemically react to generate heat. In the heater 11, when heat of a predetermined temperature or higher is applied, NH ₃ is desorbed from the reaction material 13 and starts to release NH ₃ . The predetermined temperature varies depending on the combination of the reaction medium (NH _{3 in} this embodiment) and the reaction material 13.

  As the reaction material 13, a halide represented by the composition formula MXa 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 a number specified by the valence of M, and is 2-3. The reaction material 13 is configured by press molding, for example.

  The reaction material 13 may have a heat conductivity higher than that of the reaction material 13 and may be mixed with a heat conduction material serving as a heat conduction path for transferring heat generated in the reaction material 13 to the heat exchanger 4. That is, the reaction material 13 may be manufactured by simultaneously pressing and solidifying the reaction material 13 and the heat conducting material in a mold and mixing them. As the heat conducting material, for example, carbon fiber, carbon bead, SiC bead, metal bead, polymer bead, polymer fiber, or the like is used. As the metal beads, for example, metal beads such as Cu, Ag, Ni, Ci—Cr, Al, Fe, or stainless steel are used. Moreover, you may use the material which processed metal sheets, such as a graphite sheet or aluminum, as a heat conductive material.

The storage 12 includes an adsorbent 14 that can hold and desorb NH ₃ by physical adsorption of NH ₃ as a reaction medium. As the adsorbent 14, activated carbon, carbon black, mesoporous carbon, nanocarbon, zeolite, or the like is used. Storage 12, by physically adsorbed NH ₃ to the adsorbent 14, storing NH _3.

The supply pipe 15 communicates the heater 11 and the storage 12, and distributes NH ₃ between the heater and the storage 12. That is, the supply pipe 15 constitutes a supply flow path in which NH ₃ moves between the heater 11 and the storage 12. The valve 16 is disposed in the supply pipe 15. That is, the valve 16 is disposed between the heater 11 and the storage 12. The valve 16 opens and closes the NH ₃ flow path between the heater 11 and the storage 12. For example, the valve 16 is an electromagnetic on-off valve. Opening control and closing control of the valve 16 are performed by a controller (not shown).

The reactor pressure control means 19 circulates NH ₃ in the heater 11 in one direction from the heater 11 to the storage 12 when the internal pressure of the heater 11 becomes equal to or higher than a preset first set pressure when the valve 16 is closed. Let The reactor pressure control means 19 has a bypass pipe 17 and a check valve 18 (second valve). The bypass pipe 17 is connected between the heater 11 and the valve 16 in the supply pipe 15 and between the storage 12 and the valve 16 in the supply pipe 15. The bypass pipe 17 bypasses the valve 16 disposed in the supply pipe 15. That is, the bypass pipe 17 constitutes a bypass flow path for circulating NH ₃ so as to bypass the valve 16.

The check valve 18 is disposed in the bypass pipe 17. That is, the check valve 18 is disposed between the heater 11 and the storage 12. The check valve 18 is located in parallel with the valve 16. The check valve 18 is mechanical, and is configured separately from the valve 16. The check valve 18 is a valve that closes when the pressure in the heater 11 is lower than the first set pressure, and opens mechanically when the pressure in the heater 11 reaches the first set pressure. When the check valve 18 is closed, the flow of NH ₃ from the heater 11 side to the storage 12 side is blocked, and when the check valve 18 is opened, NH ₃ flows from the heater 11 side to the storage 12 side. The first set pressure is preset by a spring (not shown) or the like that the check valve 18 has. The first set pressure is set based on the pressure resistance design value of the heater 11, and is a value of at least 3 MPa or less, for example.

The check valve 18 has a function of stopping the flow of NH ₃ from the storage 12 to the heater 11. That is, the check valve 18 always blocks the flow of NH ₃ from the storage 12 side to the heater 11 side. Therefore, when the pressure in the heater 11 reaches the first set pressure, the check valve 18 opens, so that NH ₃ moves from the heater 11 to the storage 12, but the pressure in the storage 12 reaches the first set pressure. However, NH ₃ does not move from the storage 12 to the heater 11. That is, the check valve 18 causes the heater 11 and the storage 12 to communicate with each other so that NH ₃ flows from the heater 11 to the storage 12 in one direction when the internal pressure of the heater 11 becomes equal to or higher than the first set pressure.

When the internal pressure of the storage 12 becomes equal to or higher than a preset second set pressure when the valve 16 is in the closed state, the reservoir pressure control means 22 converts the NH ₃ in the storage 12 into the heater 11, the supply pipe 15, the storage 12, To the outside of the reaction system. The reservoir pressure control means 22 has a discharge pipe 21 and a safety valve 20 (third valve). The exhaust pipe 21 connects the storage 12 and the exhaust pipe 3 that is an exhaust system of the engine. That is, the discharge pipe 21 constitutes a discharge flow path for discharging NH ₃ from the storage 12 to the exhaust pipe 3.

The safety valve 20 is disposed in the discharge pipe 21. That is, the safety valve 20 is disposed between the storage 12 and the exhaust pipe 3. The safety valve 20 is a valve that is closed when the pressure in the storage 12 is less than the second set pressure and mechanically opens when the pressure in the storage 12 reaches the second set pressure. When the safety valve 20 is closed, the flow of NH ₃ from the storage 12 to the exhaust pipe 3 is blocked, and when the safety valve 20 is opened, NH ₃ flows from the storage 12 to the exhaust pipe 3. The second set pressure is preset by a spring (not shown) or the like that the safety valve 20 has. The second set pressure is set as a value larger than the first set pressure. The safety valve 20 has a function of stopping the exhaust gas and the like from flowing from the exhaust pipe 3 to the storage 12. The safety valve 20 discharges NH ₃ from the storage 12 to the exhaust pipe 3 when the internal pressure of the storage 12 becomes equal to or higher than the second set pressure.

In the chemical heat storage device 10 as described above, the valve 16 is opened when the temperature of the exhaust gas is equal to or lower than the warm-up start temperature, whereby NH ₃ is supplied from the storage 12 to the heater 11 through the supply pipe 15. The reaction material 13 (for example, MgBr ₂ ) and NH ₃ chemically react and chemisorb (coordinate bond), and heat is generated from the reaction material 13. That is, a reaction from the left side to the right side (exothermic reaction) in the following reaction formula (A) occurs. The heat exchanger 4 is heated by the heat generated by the heater 11, and the exhaust gas is heated via the heat exchanger 4.
MgBr ₂ + xNH ₃ ＭｇMg (NH ₃ ) xBr ₂ (A)

After a predetermined time has elapsed since the valve 16 was opened, or when the temperature of the exhaust gas from the engine 2 becomes equal to or higher than the predetermined temperature, the warm-up during the operation of the engine 2 ends. Then, after the warm-up is completed, the heated exhaust gas heat is applied to the reaction material 13 of the heater 11, whereby NH ₃ is desorbed from the reaction material 13. That is, a reaction (regeneration reaction) from the right side to the left side in the above reaction formula (A) occurs. At this time, if the valve 16 is opened, NH ₃ desorbed from the reaction material 13 can move from the heater 11 to the storage 12 through the supply pipe 15. When the NH ₃ returns to the storage 12, the NH ₃ is recovered it is physically adsorbed by the adsorbent 14 in the storage 12.

  Next, with reference to FIG. 2, operation | movement of the chemical thermal storage apparatus 10 which concerns on this embodiment is demonstrated. FIG. 2 is a conceptual diagram showing the operation of the chemical heat storage device 10 shown in FIG. 2A shows a case where the inside of the heater 11 is in an overpressure state, and FIG. 2B shows a case where the inside of the storage 12 is in an overpressure state.

For example, when the engine 2 is stopped during the recovery of NH ₃ , no current is supplied to the valve 16 and the valve 16 is closed. In this case, as shown in FIG. 2A, the heater 11 is filled with high-temperature NH ₃ gas, and the pressure in the heater 11 rises rapidly, resulting in an overpressure state. At this time, when the pressure in the heater 11 reaches the first set pressure, the check valve 18 opens, so that NH ₃ in the heater 11 moves to the storage 12 through the bypass pipe 17. Thereby, the inside of the heater 11 can be prevented from being in an abnormal overpressure state.

When NH ₃ in the heater 11 moves to the storage 12 through the bypass pipe 17, as shown in FIG. 2B, the storage 12 is filled with high-temperature NH ₃ gas, and the pressure in the storage 12 suddenly increases. To rise. When the pressure in the storage 12 reaches the second set pressure, the safety valve 20 is opened, so that NH ₃ in the storage 12 is discharged to the exhaust pipe 3 through the discharge pipe 21. Thereby, it is possible to prevent the storage 12 from being in an abnormal overpressure state.

Further, in the present embodiment, the second set pressure is set to a value larger than the first set pressure. Assuming that the second set pressure is set to a value equal to or lower than the first set pressure, the pressure in the storage 12 is relatively short after the NH ₃ has moved from the heater 11 to the storage 12. May be reached. Thus, if the pressure in the storage 12 reaches the second set pressure relatively soon after the NH ₃ moves from the heater 11 to the storage 12, for example, the amount of NH _{3 in} the storage 12 is stored in the storage 12. A malfunction may occur in which NH ₃ is discharged from the storage 12 to the exhaust pipe 3 in spite of being less than the allowable amount.

For example, NH ₃ may not be sufficiently physically adsorbed to the adsorbent 14 in the storage 12 immediately after NH ₃ moves from the heater 11 to the storage 12. As a result, when the storage 12 is filled with high-temperature NH ₃ gas and the pressure in the storage 12 suddenly increases, the NH ₃ in the storage 12 is less than the allowable storage capacity of the storage 12. When the pressure in the storage 12 reaches the second set pressure, the safety valve 20 is opened, and NH ₃ may be discharged from the storage 12 to the exhaust pipe 3. As a result, the amount of NH ₃ accommodated in the heater 11 and the storage 12 decreases, and there is a possibility that the amount of NH ₃ necessary for performing the exothermic reaction and the regeneration reaction may be smaller.

In order to deal with this problem, in the present embodiment, since the second set pressure is set to a value larger than the first set pressure, the pressure in the storage 12 rapidly increases as shown in FIG. Even so, it is possible to prevent the pressure in the storage 12 from reaching the second set pressure immediately after the NH ₃ moves from the heater 11 to the storage 12. Thereby, in the chemical heat storage apparatus 10 which concerns on this embodiment, generation | occurrence | production of said malfunction can be suppressed, As a result, the quantity of the reaction medium required in order to perform exothermic reaction and regeneration reaction appropriately in a reaction system It becomes possible to keep.

As described above, in the chemical heat storage device 10 according to the present embodiment, even when the valve 16 that opens and closes the NH ₃ flow path between the heater 11 and the storage 12 is closed, the pressure in the heater 11 is the first. When the pressure exceeds the set pressure, the reactor pressure control means 19 causes the heater 11 and the storage 12 to communicate with each other, and NH ₃ moves from the heater 11 to the storage 12 in one direction. Thereby, the abnormal overpressure state in the heater 11 can be prevented. When the pressure in the storage 12 becomes equal to or higher than the second set pressure, NH ₃ is discharged from the storage 12 to the exhaust pipe 3 by the storage pressure control means 22, thereby preventing an abnormal overpressure state in the storage 12. Can do. Here, since the heater 11 is accompanied by a temperature change due to a chemical reaction, the heater 11 is likely to be in an overpressure state compared to the storage 12. In the chemical heat storage device 10 according to the present embodiment, when the pressure in the heater 11 increases and becomes equal to or higher than the first set pressure, the NH ₃ in the heater 11 is replaced with the heater 11, the storage 12, and the supply pipe 15. The inside of the heater 11 is prevented from being overpressured by being distributed to the storage 12 and stored in the storage 12 without being discharged outside the reaction system including When the pressure in the storage 12 rises to become the second set pressure or higher, the NH ₃ in the storage 12 is discharged to the outside of the reaction system without flowing through the heater 11 that tends to be in an overpressure state. This prevents the storage 12 from being overpressured. Thereby, an abnormal overpressure state inside the heater 11 and the storage 12 can be prevented while reducing the possibility that NH ₃ is discharged to the outside of the reaction system. Further, since the second set pressure is larger than the first set pressure, even if NH ₃ moves from the heater 11 to the storage 12 because the pressure in the heater 11 is equal to or higher than the first set pressure, the pressure in the storage 12 immediately increases to the first set pressure. It is possible to suppress reaching the two set pressures. As a result, for example, it is possible to suppress the occurrence of a malfunction in which NH ₃ is discharged from the storage 12 even though the amount of NH _{3 in} the storage 12 is equal to or less than an allowable amount that can be stored in the storage 12. As described above, an abnormal overpressure state inside the heater 11 and the storage 12 can be appropriately prevented. Furthermore, as a result of suppressing the occurrence of the malfunction, it is possible to appropriately maintain the amount of reaction medium necessary for performing the exothermic reaction and the regeneration reaction in the reaction system.

Further, in the present embodiment, when the pressure in the storage 12 becomes the second set on the pressure or the order to the NH ₃ through the discharge pipe 21 by the relief valve 20 to flow from the storage 12 side to the exhaust pipe 3, the NH ₃ It can be discharged into the exhaust system, not in the atmosphere.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, You may change in the range which does not change the summary described in each claim, or may apply to others.

For example, in the chemical heat storage device 10 according to the above-described embodiment, the valve 16 that is the first valve and the check valve 18 that is the second valve are provided separately, but instead, the chemical heat storage device according to one embodiment. In the apparatus, the first valve may be configured as a unit together with the second valve. That is, in the first valve configured as a unit together with the second valve, NH ₃ flows in both directions between the heater 11 and the storage 12 when the pressure in the heater 11 is lower than the first set pressure. Acts as an electromagnetic on-off valve so that it can On the other hand, when the pressure in the heater 11 is equal to or higher than the first set pressure, the first valve configured as the one unit is a check so as to stop the flow of NH ₃ from the storage 12 to the heater 11. Acts as a valve. According to such a configuration, it is possible to appropriately prevent an abnormal overpressure state in the heater 11 and the storage 12 while minimizing the number of valves used in the chemical heat storage device.

  Further, in this case, the reactor pressure control means has a bypass pipe bypassing the first valve and a second valve disposed in the bypass pipe, and the first valve and the second valve are unitized. The reactor pressure control means can be integrated with the first valve, and an abnormal overpressure state in the heater 11 and the storage 12 can be appropriately prevented while preventing an increase in the size of the apparatus.

  Further, the valve 16 may be a valve other than the electromagnetic type. Further, the valve 16 is not limited to a binary control on-off valve, and may be a proportional valve or a valve configured by combining an on-off valve and a proportional valve.

  In the said embodiment, although the heater 11 was arrange | positioned around the exhaust pipe 3 so that it might correspond to the heat exchanger 4 which is heating object, and it had a cross-sectional annular shape, it is not restricted to this. For example, you may arrange | position a heater so that it may correspond only to a part of heating object. In addition, the heater may be disposed at a location other than the portion where the heating target is provided in the exhaust pipe, and may be disposed inside the exhaust pipe in order to heat the exhaust gas, for example. When a heater is arranged inside the exhaust pipe, for example, a configuration in which a plurality of heaters and a heat exchange unit are alternately stacked, the heat exchange unit is integrated with the heater, and exhaust gas is exhausted through the heat exchange unit by the heater. You may heat.

  A catalyst coat layer may be formed on part or all of the surface of the heat exchanger 4. In the above embodiment, the heating object is the heat exchanger 4. However, the heating object may be another catalyst such as DOC 5 or exhaust gas flowing through the exhaust pipe 3.

The reaction medium introduced into the reactor is not limited to NH ₃ and may be, for example, H ₂ O, alcohol, CO ₂ or the like.

  In the said embodiment, although the chemical thermal storage apparatus was applied to the diesel engine 2 which is an internal combustion engine of a vehicle, it is not restricted to this. For example, the chemical heat storage device may be applied to a gasoline engine or the like.

  Further, the chemical heat storage device may be a device that heats a heating target provided other than the exhaust system of the engine. Such a heating target may be various heat media such as engine oil, cooling water, or air. At this time, a heat exchanger may be disposed on the path through which the heat medium flows, and the heat exchanger may be heated by the chemical heat storage device. Further, the chemical heat storage device may be applied to other than the engine.

  DESCRIPTION OF SYMBOLS 3 ... Exhaust pipe (exhaust system), 10 ... Chemical heat storage device, 11 ... Heater (reactor), 12 ... Storage (reservoir), 13 ... Reactant, 15 ... Supply pipe (connection pipe), 16 ... Valve (No. (1 valve), 17 ... bypass pipe, 18 ... check valve (second valve), 19 ... reactor pressure control means, 20 ... safety valve (third valve), 21 ... discharge pipe, 22 ... reservoir pressure control means.

Claims (3)

A chemical heat storage device for heating a heating target,
A reactor having a reaction material that generates heat by a chemical reaction with the reaction medium when the reaction medium is supplied and absorbs heat to release the reaction medium when heated;
A reservoir for storing the reaction medium;
A connecting pipe that communicates the reactor and the reservoir and allows a reaction medium to flow between the reactor and the reservoir;
A first valve disposed in the connecting pipe and opening and closing a flow path of a reaction medium between the reactor and the reservoir;
Reaction in which the reaction medium in the reactor flows in one direction from the reactor to the reservoir when the internal pressure of the reactor becomes equal to or higher than a preset first set pressure when the first valve is closed. Pressure control means,
When the internal pressure of the reservoir becomes equal to or higher than a preset second set pressure when the first valve is closed, the reaction medium in the reservoir includes the reactor, the reservoir, and the connecting pipe. A reservoir pressure control means for discharging to the outside of the reaction system,
The chemical heat storage device, wherein the second set pressure is greater than the first set pressure. The reactor pressure control means has a bypass pipe that bypasses the first valve provided in the connection pipe, and a second valve that is provided in the bypass pipe,
The first valve and the second valve are configured as one unit,
The second valve always shuts off the flow of the reaction medium from the reservoir side to the reactor side, and closes when the pressure in the reactor is lower than the first set pressure and from the reactor side. The flow of the reaction medium to the reservoir side is blocked, and when the pressure in the reactor becomes equal to or higher than the first set pressure, the reaction medium is opened to flow the reaction medium from the reactor side to the reservoir side. The chemical heat storage device described in 1. The reactor is disposed in the exhaust system of the engine;
The heating object is exhaust gas discharged from the engine,
The reservoir pressure control means includes a discharge pipe connecting the reservoir and the exhaust system, and a third valve disposed in the discharge pipe,
The third valve is closed when the pressure in the reservoir is lower than the second set pressure, and shuts off the flow of the reaction medium from the reservoir side to the exhaust system, and the pressure in the reservoir is The chemical heat storage device according to claim 1 or 2, wherein a reaction medium is circulated from the reservoir side to the exhaust system when the pressure becomes a second set pressure or higher.

Images