JP2017116204A - Chemical heat storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress large deterioration of heat generation performance in the next exothermic reaction.SOLUTION: A chemical heat storage device 10 includes: a storage 11 for storing NH; a heater 12 having a reaction material 14 generating heat by chemical reaction with NHand for desorbing NHwhen heated; piping 15 for connecting the storage 11 and the heater 12; and a valve 16 disposed in the piping 15, and for opening/closing the flow passage of NH. The valve 16 is provided in the piping 15 so that the volume on the heater side in the piping becomes equal to or less than the volume of NHwhich is 8% of a total movement amount of NH.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 that is applied to an exhaust gas purification system that purifies exhaust gas discharged from an internal combustion engine of a vehicle and that heats a heating target provided in the exhaust system of the internal combustion engine is known. For example, in the chemical heat storage device described in Patent Document 1, a reservoir that stores a reaction medium, and a reactor that is disposed around or inside a heating target and includes a reaction material that chemically reacts with the reaction medium to generate heat. And a pipe for connecting the reservoir and the reactor and supplying the reaction medium from the reservoir to the reactor.

JP 2014-37791 A

  Here, in the conventional general chemical heat storage device, when the temperature of the exhaust gas discharged from the internal combustion engine is lower than the warm-up start temperature, the reaction medium stored in the reservoir is opened by opening the valve disposed in the pipe Is fed to the reactor through piping. As a result, the supplied reaction medium and the reaction material in the reactor chemically react to generate heat. That is, an exothermic reaction occurs. The object to be heated is heated by the heat generated by the exothermic reaction. Further, when the temperature of the exhaust discharged from the internal combustion engine becomes higher than the reaction medium regeneration temperature, the heat of the exhaust is given to the reaction material in the reactor, and the reaction medium is desorbed from the reaction material in the reactor. That is, a regeneration reaction occurs. The desorbed reaction medium is collected in the reservoir through the pipe, and the valve disposed in the pipe is closed at the final stage of the regeneration reaction.

  The movement of the reaction medium between the reservoir and the reactor as described above is performed by utilizing a differential pressure generated between the pressure in the reactor and the pressure in the reservoir. For this reason, after the valve is closed in the final stage of the regeneration reaction, the reaction medium remains between the reactor and the valve in the pipe. When the reactor temperature is lowered with the valve closed, at least a part of the reaction medium remaining in the pipe moves to the reactor and reacts again with the reaction material in the reactor. As a result, there is a problem in that the amount of the reaction material that reacts during the next exothermic reaction decreases, and the exothermic performance during the next exothermic reaction decreases.

  Then, an object of this invention is to provide the chemical thermal storage apparatus which can suppress the significant fall of the exothermic performance at the time of the next exothermic reaction.

  The chemical heat storage device according to the present invention includes a reservoir for storing a reaction medium, a reactor having a reaction material that generates heat and desorbs the reaction medium when heated by a chemical reaction with the reaction medium, and a reaction between the reservoir and the reactor. A pipe connected to the reactor, and a valve disposed in the pipe to open and close the flow path of the reaction medium, and the internal volume from the connection portion of the pipe to the reactor to the valve was accommodated in the reactor A valve is connected to the piping so that the amount of the reaction medium corresponding to 8% of the total amount of movement of the reaction medium, which is the amount of the reaction medium that can be adsorbed to the reaction material, is equal to or less than the value converted into the volume at the reaction medium filling pressure of the reservoir. Is provided.

  In the chemical heat storage device according to the present invention, the amount of the reaction medium remaining in the pipe from the connection portion to the valve in the state where the valve is closed in the final stage of the regeneration reaction is the total movement amount of the reaction medium that can be adsorbed to the reaction material. Of 8% or less. For this reason, the reduction of the reaction material which can be used at the time of the next exothermic reaction is suppressed, and as a result, the significant decrease in the exothermic performance of the chemical heat storage device at the time of the next exothermic reaction can be suppressed.

  In the chemical heat storage device according to the present invention, the valve may be provided adjacent to the reactor. In this case, the distance from the valve to the connection portion of the reactor with the reactor is very short, so even if the diameter of the piping used for smooth movement of the reaction medium in the piping is increased, the valve The amount of the reaction medium remaining in the pipe from the connection part to the valve in the closed state can be 8% or less of the total movement amount that can be reliably adsorbed to the reaction material.

  According to the present invention, it is possible to suppress a significant decrease in exothermic performance during the next exothermic reaction.

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. NH ₃ is a graph showing a map data used for recovery of acquisition. Piping heater-side volume is a diagram showing a specific example of the arrangement of the valve provided in the pipe so as not to exceed 8% NH ₃ of the volume of NH ₃ total moving amount. The graph of the temperature change of the reaction material at the time of the 1st exothermic reaction is shown. It is a schematic block diagram which shows the oil circulation system provided with the chemical heat storage apparatus which concerns on one Embodiment of this invention.

  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 illustrating an exhaust purification system including a chemical heat storage device according to an embodiment of the present invention.

  The exhaust 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 removes harmful substances (environmental pollutants) contained in exhaust discharged from the engine 2. Purify. The exhaust purification system 1 includes a heat exchanger 4, an oxidation catalyst (DOC: Diesel Oxidation Catalyst) 5, which are arranged in order from an upstream side to a downstream side in an exhaust pipe 3 which 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 are provided.

The heat exchanger 4 transfers heat between the exhaust from the engine 2 and a reaction material 14 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. 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 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.

  Exhaust temperature sensors 21 are disposed on the upstream side and the downstream side of the heat exchanger 4 in the exhaust pipe 3. The exhaust temperature sensor 21 detects the temperature of exhaust from the engine 2 that flows in the exhaust pipe 3. The exhaust gas temperature sensor 21 detects the temperature of exhaust gas from the engine 2 at regular intervals, for example, and outputs the detected temperature information to the controller 20 described later.

  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 engine 2 is started, the temperature of the exhaust gas immediately after being discharged from the engine 2 is as low as 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 of each catalyst to the activation temperature in order to exhibit the purification ability of each catalyst.

  Therefore, the exhaust gas purification system 1 according to the present embodiment includes a chemical heat storage device 10 that heats the exhaust gas via the heat exchanger 4 arranged on the most upstream side of the exhaust pipe 3. When the chemical heat storage device 10 heats the exhaust gas via the heat exchanger 4, the exhaust gas whose temperature is higher than that of the upstream side flows on the downstream side of the heat exchanger 4, and the catalyst is activated early. Can do.

The chemical heat storage device 10 uses the NH ₃ as a reaction medium and utilizes a reversible chemical reaction to heat the exhaust gas to be heated via the heat exchanger 4 without any external energy. In other words, the chemical heat storage device 10 is typically leave accumulated heat by the state to separate the reaction member 14 and the NH ₃ to be described later, when the heating of the heat exchanger 4 is required, reacting the NH ₃ By supplying to the material 14, heat is generated from the reaction material 14 and the exhaust gas is heated through the heat exchanger 4.

  The chemical heat storage device 10 includes a storage 11 (reservoir), a heater 12 (reactor), a pipe 15, a valve 16, a temperature sensor 22, a pressure sensor 23, and a controller 20.

Storage 11 includes an adsorbent 13 capable of leaving the holding and NH ₃ by physical adsorption of NH _3. As the adsorbent 13, activated carbon, carbon black, mesoporous carbon, nanocarbon, zeolite, or the like is used. Storage 11, by physically adsorbed NH ₃ to the adsorbent 13, for storing NH _3.

  The heater 12 is disposed around the heat exchanger 4 so as to heat the heat exchanger 4. The heater 12 has, for example, an annular cross section surrounding the heat exchanger 4. The cross-section of the annular cross section is a surface obtained by cutting the heater 12 perpendicular to the exhaust flow direction in the exhaust pipe 3.

The heater 12 has a reaction material 14 that chemically reacts with NH ₃ to generate heat, and stores the heat by desorption of NH ₃ by being heated by the heat of exhaust gas that has become high temperature. Therefore, in the heater 12, when NH ₃ is supplied from the storage 11, the NH ₃ and the reaction material 14 chemically react to generate heat. In the heater 12, when heat equal to or higher than the desorption start temperature is applied, NH ₃ is desorbed from the reaction material 14 and begins to release NH ₃ . Since the exothermic temperature and the desorption start temperature differ depending on the combination of the reaction medium (NH _{3 in} this embodiment) and the reaction material 14, the reaction material 14 is appropriately selected according to the target heating temperature to be heated. Further, the reaction material 14 has a characteristic that the exothermic temperature changes depending on the pressure in the container when chemically reacting with the reaction medium (NH _{3 in} this embodiment). Therefore, in order to obtain desired heat generation characteristics with the heater 12, the NH ₃ filling pressure (reaction medium filling pressure) filled in the storage 11 is set based on the heat generation temperature of the reaction material 14. A value obtained by converting a predetermined amount of NH ₃ into a volume at the reaction medium filling pressure of the storage 11 is also referred to as “NH ₃ volume” hereinafter.

  As the reaction material 14, 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 14 may be press-molded at a pressure of 20 to 100 MPa, for example. By this press molding, the reaction material 14 is molded into a molded body such as a plate, pellet, or tablet.

  The reaction material 14 disposed in the heater 12 is made of a heat conduction material that has a higher thermal conductivity than the reaction material 14 and serves as a heat conduction path for efficiently transmitting heat generated in the reaction material 14 to the heat exchanger 4. You may mix. For example, when forming the reaction material 14 into a plate-shaped, pellet-shaped, or tablet-shaped molded body, the powdered reaction material 14 and the heat conducting material are uniformly mixed with a powder mixer or the like, and the mixture is molded. It is also possible to press and harden it into 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 pipe 15 connects the storage 11 and the heater 12, and distributes NH ₃ between the storage 11 and the heater 12. That is, the pipe 15 constitutes a supply channel through which NH ₃ moves between the storage 11 and the heater 12. When comparing pipes having the same thickness, the larger the outer diameter of the pipe 15, that is, the larger the inner diameter of the pipe 15, the more NH _{3 is} passed through the pipe 15 between the storage 11 and the heater 12 in a shorter time. Can be moved. For example, a 3/8 inch pipe or a 1/2 inch pipe, which will be described later, having an inner diameter of 7 mm or more may be used as the pipe 15.

The valve 16 is disposed in the pipe 15. That is, the valve 16 is located between the storage 11 and the heater 12. The valve 16 opens and closes the NH ₃ flow path between the storage 11 and the heater 12. For example, the valve 16 is an electromagnetic on-off valve. The controller 20 controls the opening and closing of the valve 16.

  The temperature sensor 22 is provided in the storage 11. The temperature sensor 22 detects the temperature in the storage 11 at regular intervals, for example, and outputs the detected temperature information to the controller 20.

  The pressure sensor 23 is provided in the storage 11. The pressure sensor 23 detects the pressure in the storage 11 at regular intervals, for example, and outputs the detected pressure information to the controller 20.

  The controller 20 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The controller 20 is connected to various sensors such as an exhaust temperature sensor 21, a temperature sensor 22, and a pressure sensor 23, and appropriately acquires information necessary for control from the plurality of sensors. The controller 20 is connected to the valve 16, performs a predetermined process based on the acquired information, and performs open control and close control of the valve 16 as necessary. The controller 20 may be dedicated to the chemical heat storage device 10 or may be incorporated as a function of an ECU such as an engine ECU (Electronic Control Unit).

  The controller 20 includes a valve opening / closing unit 24, a collection amount acquisition unit 25, and a determination unit 26.

  The valve opening / closing unit 24 controls the opening / closing of the valve 16. The valve opening / closing part 24 determines whether or not the temperature of the exhaust gas upstream of the heat exchanger 4 detected by the exhaust gas temperature sensor 21 is lower than the warm-up start temperature during the operation of the engine 2. If the valve opening / closing unit 24 determines that the exhaust gas temperature is lower than the warm-up start temperature, for example, when the exhaust gas temperature is low, such as immediately after the engine 2 is started, the valve opening / closing unit 24 performs the opening control of the valve 16. . That is, the valve opening / closing unit 24 supplies current to the valve 16 to switch the valve 16 from the closed state to the open state. Here, the warm-up start temperature is set, for example, as a catalyst activation temperature such as DOC 5 of the exhaust purification system 1 or a threshold temperature lower than the catalyst activation temperature by a predetermined value. This warm-up start temperature is set based on the activation temperature of a catalyst such as DOC5.

As described above, when the temperature of the exhaust gas is lower than the warm-up start temperature, the valve 16 is opened, so that NH ₃ accommodated in the storage 11 is supplied to the heater 12 through the pipe 15, and the reaction material 14 ( For example, MgBr ₂ ) and NH ₃ chemically react and chemisorb (coordinate bond), and heat is generated from the reaction material 14. 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 12, and the exhaust gas is heated via the heat exchanger 4.
MgBr ₂ + xNH ₃ ＭｇMg (NH ₃ ) xBr ₂ + heat (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 a preset warm-up end temperature, the valve 16 is controlled to be closed by the valve opening / closing unit 24 and the engine 2 is in operation. Warm-up in is completed. After the warm-up, when the engine 2 enters a steady operation state and the temperature of the exhaust gas discharged from the engine 2 becomes sufficiently high, the heat of the exhaust gas reacts with the heater 12 via the heat exchanger 4 this time. It will be given to the material 14. That is, the reaction material 14 is heated by the exhaust gas through the heat exchanger 4.

When the temperature of the exhaust gas becomes equal to or higher than a predetermined recovery temperature, a regeneration reaction in which NH ₃ is desorbed from the reaction material 14 in a state where NH ₃ is chemically adsorbed inside the heater 12 (from the right side in the above reaction formula (A)). Reaction to the left side) occurs. Here, the predetermined recovery temperature is the temperature of the exhaust gas that can give the reaction material 14 heat sufficient to desorb NH ₃ from the reaction material 14. For example, when the temperature of the exhaust gas reaches a predetermined recovery temperature, the valve 16 is controlled to be opened by the valve opening / closing unit 24, and NH ₃ desorbed from the reaction material 14 can move from the heater 12 to the storage 11 through the pipe 15. When NH ₃ returns to the storage 11, NH ₃ is physically adsorbed by the adsorbent 13 in the storage 11 and collected.

At the time of NH ₃ recovery through the pipe 15, the valve opening / closing control of the valve 16 by the valve opening / closing unit 24 is performed based on, for example, a value related to the NH ₃ recovery amount acquired by the recovery amount acquisition unit 25. Here, the value and the related recovery of NH _3, a value related to recovery of NH ₃ recovered from the heater 12 to the storage 11, the recovery amount per se of NH ₃ (hereinafter, also referred to as "NH ₃ recovered amount" ) even to good recovery of NH ₃ (hereinafter, may be referred to as "NH ₃ recovery") value calculated on the basis of NH ₃ recovery of such. In the present embodiment, as the value relating to the recovery of NH _3, it is used NH ₃ recovery.

Specifically, the valve opening / closing unit 24 controls the valve 16 to be closed when the determination unit 26 determines that the NH ₃ recovery rate exceeds a predetermined recovery target value. Thereby, the flow of NH _{3 in} the pipe 15 is blocked. Here, the recovery target value is a value appropriately set by the user or the like, and is, for example, the amount of NH ₃ that can heat the heating target to the target temperature in the next exothermic reaction. The recovery target value is set to, for example, about 80% in consideration of NH ₃ remaining in the heater 12 or the pipe 15 without being recovered in the storage 11.

The collection amount acquisition unit 25 acquires the NH ₃ recovery rate using, for example, the map data shown in FIG. FIG. 2 is a graph showing map data used for obtaining the NH ₃ recovery rate. FIG. 2A is a graph showing the relationship between the temperature in the storage 11 and the saturated vapor pressure of NH ₃ , the horizontal axis shows the temperature [° C.] in the storage 11, and the vertical axis shows the saturation of NH ₃ . Vapor pressure [kPa] is shown. FIG. 2B is a graph showing the relationship between the relative pressure of the adsorbent 13 in the storage 11 and the NH ₃ adsorption amount, the horizontal axis indicates the relative pressure, and the vertical axis indicates the NH ₃ adsorption amount [g]. Indicates. Here, the relative pressure is a ratio (P / Psat) between the saturated vapor pressure of NH _{3 and} the pressure in the storage 11. Note that the relationship of the NH ₃ adsorption amount with respect to the relative pressure of the adsorbent 13 is obtained in advance by experiments.

In the collection amount acquisition unit 25, map data shown in the graphs of FIGS. 2A and 2B is set in advance. The recovery amount acquisition unit 25 acquires the NH ₃ adsorption amount using the relationship, and acquires the NH ₃ recovery rate based on the acquired NH ₃ adsorption amount. Specifically, the collection amount acquisition unit 25 uses map data having the relationship shown in the graph of FIG. 2A based on the temperature T in the storage 11 indicated by the temperature information output from the temperature sensor 22. To obtain the saturated vapor pressure Psat of NH ₃ .

Subsequently, the collection amount acquisition unit 25 determines the saturation vapor pressure Psat and the pressure P based on the acquired saturated vapor pressure Psat of NH ₃ and the pressure P in the storage 11 indicated by the pressure information output from the pressure sensor 23. The relative pressure, which is the ratio of Subsequently, the collection amount acquisition unit 25 acquires the NH ₃ adsorption amount Y using the map data having the relationship shown by the graph in FIG. 2B based on the calculated relative pressure. Thus, the NH ₃ adsorption amount Y stored in the storage 11 is estimated from the temperature T and the pressure P in the storage 11.

The recovery amount acquisition unit 25 subtracts the remaining amount remaining in the storage 11 from the heater 12 in order to keep the pressure of the storage 11 and the heater 12 at a predetermined pressure from the NH ₃ adsorption amount Y during warm-up. The amount of NH ₃ recovered in the storage 11 is acquired. Further, the recovery amount acquisition unit 25 uses the NH ₃ recovery amount as the amount of NH ₃ necessary for the exothermic reaction to obtain a desired amount of heat, that is, the amount of NH ₃ for movement used for the heat generation in the heater 12. The NH ₃ recovery rate is obtained by dividing by.

The determination unit 26 makes various determinations based on the NH ₃ recovery rate acquired by the recovery amount acquisition unit 25 and outputs the determination results to the valve opening / closing unit 24. Specifically, the determination unit 26 determines whether or not the NH ₃ recovery rate exceeds the recovery target value.

In the final stage of the regeneration reaction, the valve 16 is closed when it is determined that the NH ₃ recovery rate exceeds, for example, about 80%. Therefore, a part of the moving NH ₃ is not collected in the storage 11 and remains between the valve 16 and the heater 12 in the pipe 15 after the valve 16 is closed. For this reason, when the valve 16 is closed, the remaining NH ₃ may move to the heater 12 and be adsorbed on the reaction material 14, so-called NH ₃ sucking back may occur.

In the present embodiment, the internal volume (hereinafter also referred to as “in-pipe heater side volume”) from the connection portion 15 a to the heater 12 in the pipe 15 to the valve 16 can be adsorbed by the reaction material 14 accommodated in the heater 12. the amount in which the reaction medium total moving amount of NH ₃ (hereinafter, also referred to as "NH ₃ total moving amount") and less than the value obtained by converting the volume in the reaction medium filling pressure amount storage 11 of NH _3, which corresponds to 8% The valve 16 is provided in the piping 15 so that it may become. NH ₃ and the total amount of movement, when producing the desired exothermic reactions with the heater 12, is in an amount of NH ₃ which is capable of heater 12 chemisorbed reaction material 14 disposed within (coordinate bond) . The total movement amount of NH ₃ is determined by the amount of the reaction material 14 disposed in the heater 12. For example, 2 dihydrate MgBr ₂ of a case to cause an exothermic reaction to MgBr ₂ of 6 dihydrate, when 1mol of MgBr ₂ in the arranged to the heater 12 as a reaction member 14, the 2 dihydrate MgBr _Since the amount of NH ₃ that can be chemically adsorbed to ₂ is 4 mol, the total movement amount of NH ₃ is 4 mol.

The in-pipe heater-side volume is the internal volume of the pipe 15 between the connecting portion 15a and the valve 16. The internal volume of the pipe 15 is an inner volume determined by the inner diameter and the axial length of the pipe 15. That is, in the present embodiment, the NH ₃ amount corresponding to the heater side volume in the pipe corresponding to 8% of the total NH ₃ movement amount is converted into a volume at the reaction medium filling pressure of the storage 11 (hereinafter referred to as “NH ₃ total movement”). The amount of NH ₃ remaining in the pipe 15 from the connection portion 15a to the valve 16 in the state where the valve 16 is closed in the final stage of the regeneration reaction (hereinafter also referred to as “NH ₃ volume of 8% of the amount”). , Also referred to as “NH ₃ suck back amount”) is 8% or less of the total NH ₃ transfer amount.

Next, with reference to FIG. 3, a specific example of the arrangement of the valve 16 when the pipe in the heater-side volume is not more than 8% NH ₃ of the volume of NH ₃ total moving amount. Figure 3 is a diagram showing a specific example of the arrangement of the valve 16 provided in the pipe 15 as the pipe in the heater-side volume is equal to or less than 8% NH ₃ of the volume of NH ₃ total moving amount. FIG. 3A shows a case where a pipe 15 (hereinafter also referred to as “1/2 inch pipe”) having an outside diameter of 1/2 inch, a wall thickness of 0.89 mm, and an inside diameter of 10.9 mm is used. An example of the arrangement configuration of the valve 16 is shown. FIG. 3B uses a pipe 15 (hereinafter also referred to as “3/8 inch pipe”) having an outer diameter of 3/8 inch, a thickness of 0.89 mm, and an inner diameter of 7.72 mm. An example of the arrangement configuration of the valve 16 is shown.

As shown in FIG. 3A, for example, the total amount of NH ₃ transferred to obtain a desired exothermic characteristic is 0.028 mol, the temperature is 25 ° C., the reaction medium filling pressure to the storage 11 is 850 kPa, with state equation PV = nRT, 8% NH ₃ of the volume of NH ₃ total moving amount is about 6.53Cc. In this case, 1/2 when using a inch tube, the position of the valve 16 the pipe in the heater-side volume is not more than 8% NH ₃ of the volume of NH ₃ total amount of movement, the distance from the heater 12 is approximately 69.7mm The position is as follows. That is, in this case, the valve 16 has an axial length L1 from the connecting portion 15a to the valve 16 in the 1/2 inch pipe (that is, a distance between the valve 16 and the heater 12) of about 69.7 mm or less. Placed in position. The axial length L1 is smaller than the axial length L2 between the valve 16 and the storage 11 in a ½ inch pipe, for example. That is, the distance between the valve 16 and the heater 12 in the ½ inch pipe is shorter than the distance between the valve 16 and the storage 11 in the ½ inch pipe. Therefore, NH ₃ is less likely to exist between the valve 16 and the heater 12 in the ½ inch pipe than between the valve 16 and the storage 11 in the ½ inch pipe.

  The overall axial length of the 1/2 inch tube is at least greater than twice the axial length L1. In this case, the axial length of the entire 1/2 inch tube can be set to a length (for example, about 500 mm) that allows the storage 11 and the heater 12 to be sufficiently separated from each other. The mountability of the heat storage device 10 can be improved. In addition, axial direction length L2 is not restricted above, For example, axial direction length L1 or less may be sufficient. That is, the axial length of the entire ½ inch tube may be not more than twice the axial length L1.

As shown in FIG. 3B, for example, the total amount of NH ₃ transferred to obtain desired exothermic characteristics is 0.028 mol, the temperature is 25 ° C., the reaction medium filling pressure to the storage 11 is 850 kPa, with state equation PV = nRT, 8% NH ₃ of the volume of NH ₃ total moving amount is about 6.53Cc. At this time, 3/8 when using inch pipe, the position of the valve 16 the pipe in the heater-side volume is not more than 8% NH ₃ of the volume of NH ₃ total amount of movement, the distance from the heater 12 is approximately 139.5mm The position is as follows. That is, in this case, the valve 16 has an axial length L3 (that is, a distance between the valve 16 and the heater 12) from the connecting portion 15a to the valve 16 in the 3/8 inch pipe of about 139.5 mm or less. Placed in position. The axial length L3 is smaller than the axial length L4 between the valve 16 and the storage 11 in a 3/8 inch pipe, for example. That is, the distance between the valve 16 and the heater 12 in the 3/8 inch pipe is shorter than the distance between the valve 16 and the storage 11 in the 3/8 inch pipe. Therefore, NH ₃ is less likely to exist between the valve 16 and the heater 12 in the 3/8 inch pipe than between the valve 16 and the storage 11 in the 3/8 inch pipe.

  The overall axial length of the 3/8 inch tube is at least greater than twice the axial length L3. In this case, the axial length of the entire 3/8 inch tube can be set to a length (for example, about 500 mm) at which the storage 11 and the heater 12 can be positioned sufficiently apart from each other. Can be improved. In addition, axial direction length L4 is not restricted above, For example, axial direction length L3 or less may be sufficient. That is, the axial length of the entire 3/8 inch tube may be not more than twice the axial length L3.

Further, for example, in the case of using pipes 15 of various sizes including a 1/2 inch pipe or a 3/8 inch pipe, the valve 16 may be provided adjacent to the heater 12. More specifically, the valve 16 may be provided in a connection portion 15 a with the heater 12 in the pipe 15. Since the valve 16 is adjacent to the heater 12, the distance between the valve 16 and the heater 12 in the pipe 15 becomes very short. Therefore, NH ₃ is formed between the valve 16 and the heater 12 in the pipe 15. Certainly it will be difficult to exist.

Next, with reference to FIGS. 4 and Table 1, when pipe heater-side volume is not more than 8% NH ₃ of the volume of NH ₃ total movement amount, i.e. NH ₃ suck back amount of NH ₃ total transfers 8 An example of the effect in the case of% or less will be described. In this example, a storage for storing NH _3, and piping connecting a heater and a storage heater with a reaction material capable of leaving the NH ₃ upon heating as well as heating by chemical reaction with NH _3, pipe An experiment relating to heat generation performance was performed as follows using a chemical heat storage device provided with a valve for opening and closing the NH ₃ flow path.

First, about 1.3 g of MgBr ₂ and about 0.8 g of carbon fiber are mixed, a reaction material formed into a pellet by press molding is inserted into the heater, and after evacuation, 90 ° C. to 150 ° C. Heated to about ° C. Subsequently, NH ₃ was supplied from the storage to the heater at 850 kPa to cause an exothermic reaction and waited for 10 minutes. Subsequently, the heater was heated to 400 ° C. and waited for 1 hour to cause a regeneration reaction. Thereafter, the valve was closed and allowed to stand until the temperature of the heater reached 150 ° C., then the valve was opened again and NH ₃ was supplied from the storage to the heater to cause an exothermic reaction. And the exothermic temperature of the reaction material at the time of the said exothermic reaction was measured, and the exothermic performance was evaluated. Hereinafter, the second exothermic reaction after the regeneration reaction is also referred to as “next exothermic reaction”.

  As a reference for evaluating the exothermic performance, FIG. 4 shows a graph of the temperature change of the reaction material during the first exothermic reaction. The horizontal axis of FIG. 4 shows elapsed time [s], and the vertical axis of FIG. 4 shows the temperature of the reaction material. As shown in FIG. 4, the peak value of the temperature of the reaction material during the exothermic reaction (hereinafter also referred to as “exothermic temperature”) was about 245 ° C. In an exhaust purification system or the like to which a chemical heat storage device is applied, since instantaneous heat output is important, the heat generation performance can be evaluated using this heat generation temperature.

As a comparative example, the valve in a position such as 10% NH ₃ by volume to become such a position of the pipe in the heater-side volume NH ₃ total movement amount, i.e. NH ₃ suck back amount is 10% of the NH ₃ total moving amount And the above experiment was performed. Further, as an example, 8% NH ₃ by volume or less to become such a position of the pipe in the heater-side volume NH ₃ total movement amount, i.e. NH ₃ suck back amount is equal to or less than 8% of the NH ₃ total movement amount position The above-described experiment was conducted with a valve disposed on the surface. In the first embodiment, the valve is arranged at a position where the NH ₃ sucking back amount is 8% of the total NH ₃ moving amount, and in the second embodiment, the NH ₃ sucking back amount is 2% of the total NH ₃ moving amount. The valve 16 was arranged in The results of Comparative Examples and Examples are shown in Table 1 below. Table 1 is a table showing the exothermic temperature according to the NH ₃ absorption amount. Table 1 shows the exothermic temperature of the reaction material during the first exothermic reaction as a reference value for evaluating the exothermic performance in addition to the results of the comparative example and the example.

As shown in Table 1, in the comparative example, a 10% NH ₃ suck return amount is NH ₃ total moving amount, compared the amount of NH ₃ which moves to the heater would again react with the reactive material in the heater It is becoming more and more popular. In this case, the exothermic temperature of the reaction material during the next exothermic reaction was about 181 ° C., and the exothermic performance was relatively greatly reduced from the reference value of about 245 ° C. This reduces the amount of reaction material that can be used in the next exothermic reaction, and as a result, the desired exothermic reaction (for example, the hydrate MgBr _{2 is changed} to the hexahydrate MgBr ₂ in the next exothermic reaction). This indicates that the exothermic reaction could not be performed.

In contrast, in Examples 1 and 2, and the NH ₃ suck back amount is more than 8% of the NH ₃ total movement amount, the amount of NH ₃ which moves to the heater would again react with the reactive material in the heater It is running low. In Example 1, the exothermic temperature of the reaction material at the next exothermic reaction is about 242 ° C., and in Example 2, the exothermic temperature of the reaction material at the next exothermic reaction is about 220 ° C. The decrease in heat generation performance with respect to the reference value of about 245 ° C. was suppressed as compared with the comparative example. This is because, as a result of the reduction in the amount of the reaction material that can be used in the next exothermic reaction, the desired exothermic reaction (for example, the exotherm that converts the hydrate MgBr ₂ into the hexahydrate MgBr ₂₎ Reaction).

As described above, according to the chemical heat storage device 10 according to the present embodiment, the NH ₃ absorption amount is 8% or less of the total NH ₃ movement amount. For this reason, the decrease of the reaction material 14 that can be used at the next exothermic reaction is suppressed, and as a result, a significant decrease in the exothermic performance of the chemical heat storage device 10 at the next exothermic reaction can be suppressed.

According to the above embodiment, by the valve 16 is provided adjacent to the heater 12, the distance from the valve 16 to the connection portions 15a of the heater 12 in the pipe 15 becomes very short, piping NH ₃ Even when the diameter of the pipe 15 used for smooth movement in the pipe 15 is increased, the NH ₃ suck back amount can be surely made 8% or less of the total NH ₃ movement quantity.

  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 above embodiment, the opening / closing control of the valve 16 is performed by the controller 20, but the present invention is not limited to this, and may be performed manually, for example.

In the above embodiment, one heater 12 is connected to one storage 11, but the present invention is not limited to this. For example, a plurality of heaters may be connected to one storage. Also, a pipe connecting one storage and a plurality of heaters is one main pipe connected to one storage, and a plurality of branch pipes branching from the main pipe and connected to a plurality of heaters You may have. Further, a valve may be provided in each branch pipe. In this case, the internal volume of the connection portion of the heater in each branch pipe to each valve, NH ₃ to 8% NH ₃ volume below a position of total movement amount may be the valve is provided.

  Moreover, in the said embodiment, although the heater 12 was arrange | positioned around the heat exchanger 4 and had cross-sectional annular shape, it is not restricted to this. For example, the heater may be arranged at a place other than the outside of the exhaust pipe, and for example, may be arranged inside the exhaust pipe in order to heat the exhaust. 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 the exhaust is heated by the heater through the heat exchange unit. May be.

  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, but the heating object may be another catalyst such as DOC 5 or exhaust gas flowing through the exhaust pipe 3.

In the above embodiment, the reaction medium is NH ₃ , but other reaction medium such as alcohol or water may be used. In the above embodiment, the reaction member when the reaction medium is NH _3, has been illustrated respectively the materials of the adsorbent, depending on the reaction medium used in the chemical heat storage device, the reaction member, other appropriate the adsorbent Material is used.

  In the said embodiment, although the chemical thermal storage apparatus 10 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.

  In addition, for example, the chemical heat storage device 10 may be a device that heats a heating target provided other than the exhaust system of the engine 2. 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. For example, the chemical heat storage device 10 may be applied to an oil circulation system 1A as shown in FIG.

  In FIG. 5, the oil circulation system 1A circulates engine oil for lubricating each part in the engine 2 of the vehicle. The oil circulation system 1A includes an oil pan 41, an oil pump 42, an oil filter 43, and a heat exchanger 44. The oil pan 41 stores engine oil. The engine oil that has circulated through each part in the engine 2 returns to the oil pan 41.

  The oil pump 42 sucks up the engine oil accumulated in the oil pan 41 and pumps it into the engine 2. The oil filter 43 filters engine oil dirt. The heat exchanger 44 is disposed between the oil pan 41 and the oil pump 42. The heat exchanger 44 exchanges heat between the engine oil sucked up by the oil pump 42 and the heater 12 of the chemical heat storage device 10.

  Furthermore, you may apply the chemical thermal storage apparatus 10 other than an engine.

  DESCRIPTION OF SYMBOLS 10 ... Chemical thermal storage apparatus, 11 ... Storage (reservoir), 12 ... Heater (reactor), 14 ... Reactant, 15 ... Piping, 15a ... Connection part, 16 ... Valve, L1, L3 ... Axial length.

Claims (2)

A reservoir for storing the reaction medium;
A reactor having a reaction material that generates heat and desorbs the reaction medium when heated by a chemical reaction with the reaction medium;
Piping connecting the reservoir and the reactor;
A valve disposed in the pipe for opening and closing a flow path of the reaction medium;
With
The internal volume from the connection with the reactor to the valve in the piping corresponds to 8% of the total amount of reaction medium transferred, which is the amount of reaction medium that can be adsorbed to the reaction material accommodated in the reactor. The chemical heat storage device, wherein the valve is provided in the pipe so that the amount of the reaction medium is equal to or less than a value converted into a volume at a reaction medium filling pressure of the reservoir.   The chemical heat storage device according to claim 1, wherein the valve is provided adjacent to the reactor.

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