JP2017072310A - Chemical heat storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict reduction in heat generation performance while restricting consumption power.SOLUTION: A chemical heat storage device 10 comprises a storage 11 for storing NH; a heater 12 having chemical reaction material 14 for desorption of NHupon generation of heat through chemical reaction with NHand also upon being heated; a main piping 15 for connecting the storage 11 with the heater 12; a valve 16 arranged at the main piping 15 to open or close a flow channel for NH; a bypass piping 17 for connecting the storage 11 rather than the valve 16 at the main piping 15 with the heater 12 rather than the valve 16 at the main piping 15; and a pump 30 arranged at the bypass piping 17, sucking NHleft between the heater 12 and the valve 16 in the main piping 15 under a state in which the valve 16 is closed and forcibly recovering it to the storage 11.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. A first supply channel connecting the reactor and the reservoir and supplying the reaction medium from the reservoir to the reactor; and the reactor and the reservoir in parallel with the first supply channel; And a second supply flow path for supplying the reaction medium from the reactor to the reservoir.

JP 2014-234950 A

  Here, in the conventional general chemical heat storage device, when the temperature of the exhaust gas discharged from the internal combustion engine becomes lower than the warm-up start temperature, the reaction medium stored in the reservoir is supplied to the reactor through the supply pipe. Is done. As a result, the supplied reaction medium and the reaction material in the reactor react chemically 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. Then, the desorbed reaction medium is collected in the reservoir through the supply pipe, and the valve disposed in the supply 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 supply pipe. As a result of the remaining reaction medium reacting again with the reaction material in the reactor, the amount of the reaction material that reacts at the next exothermic reaction is reduced, and there is a problem that the exothermic performance at the next exothermic reaction is lowered.

  With respect to such a problem, in the chemical heat storage device described in Patent Document 1, the pressure in the reactor is forcibly lowered by the forced recovery means provided in the second supply flow path, so that the reactor is stored in the reservoir. The reaction medium is forcibly recovered. However, in the chemical heat storage device described in Patent Document 1, since the forced recovery means is always operated during the recovery of the reaction medium and the pressure in the reactor is directly reduced, the operation time of the forced recovery means becomes longer, and the consumption Electricity will increase.

  Then, an object of this invention is to provide the chemical heat storage apparatus which can suppress the fall of heat-generating performance, suppressing power consumption.

  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 main pipe connecting the vessel, a first valve disposed in the main pipe for opening and closing the flow path of the reaction medium, a reaction from the first valve in the main pipe and the reservoir side and the first valve in the main pipe. The bypass pipe connecting the reactor side, and the reaction medium disposed in the bypass pipe and the first valve closed, sucks the reaction medium remaining between the reactor and the first valve in the main pipe And a recovery part forcibly recovering to the reservoir.

  In the chemical heat storage device according to the present invention, when the first valve is closed by the recovery unit, the reaction medium remaining between the reactor and the first valve in the main pipe is sucked, and the reaction medium is It is forcibly recovered into the reservoir. Thus, for example, even when the reaction medium remains between the reactor and the first valve in the main pipe after the first valve is closed in the final stage of the regeneration reaction, the reaction medium is recovered. It is sucked by the unit and is forcibly recovered into the reservoir. For this reason, it becomes difficult to generate | occur | produce the malfunction that the said reaction medium reacts again with the reaction material in a reactor. As a result, a decrease in the amount of the reaction material that reacts during the next exothermic reaction is suppressed, and a decrease in the exothermic performance during the next exothermic reaction is suppressed. Furthermore, the recovery unit sucks in the reaction medium remaining between the reactor and the first valve in the main pipe when the first valve is closed, so that the recovery unit is always operated during the recovery of the reaction medium. As a result, the operation time required for sucking the reaction medium is shortened and power consumption can be reduced as compared with the case where the reaction medium is sucked directly from the reactor regardless of the open / close state of the first valve. As described above, it is possible to suppress a decrease in heat generation performance while suppressing power consumption.

  In the chemical heat storage device according to the present invention, a second valve that is disposed closer to the reactor than the recovery unit in the bypass pipe, opens and closes the flow path of the reaction medium, and controls the opening and closing of the first valve and the second valve; And a control unit for controlling the operation of the recovery unit, the control unit acquires a value related to the recovery amount of the reaction medium recovered from the reactor to the reservoir, and the value related to the recovery amount is a first predetermined value. When the value is exceeded, the first valve may be controlled to close, the second valve may be controlled to open, and the recovery unit may be operated. In this case, when the value related to the recovery amount of the reaction medium recovered from the reactor to the reservoir exceeds the first predetermined value, the recovery unit operates, so the value related to the recovery amount exceeds the first predetermined value. The recovery unit is prevented from operating until there is no such event. As a result, the operation time of the recovery unit can be reliably shortened and power consumption can be reliably suppressed.

  In the chemical heat storage device according to the present invention, the control unit may close the second valve and stop the operation of the recovery unit when a predetermined time has elapsed at the latest after the recovery unit has started to operate. In this case, since the operation of the recovery unit is stopped when a predetermined time has elapsed after the recovery unit has started to operate, the operation time of the recovery unit can be further shortened to further reduce power consumption.

  In the chemical heat storage device according to the present invention, when the value related to the recovery amount becomes a second predetermined value larger than the first predetermined value before the predetermined time has elapsed since the recovery unit started to operate, The second valve may be controlled to be closed and the operation of the recovery unit may be stopped. In this case, since the recovery unit operates until the value related to the recovery amount reaches the second predetermined value, the reaction medium remaining between the reactor and the first valve in the main pipe is sufficiently recovered in the reservoir. The As a result, it is possible to reliably suppress a decrease in heat generation performance. Furthermore, since the operation of the recovery unit stops when the value related to the recovery amount reaches the second predetermined value even before the predetermined time has elapsed since the recovery unit started to operate, the reactor in the main pipe It is possible to prevent the recovery section from operating until after the reaction medium remaining between the first valve and the storage valve is sufficiently recovered to the reservoir, thereby further reducing power consumption.

  According to the present invention, it is possible to suppress a decrease in heat generation performance while suppressing power consumption.

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. It is a flowchart which shows the process sequence of a valve opening / closing part, a pump operation part, and a determination part. 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 main pipe 15, a valve 16 (first valve), a bypass pipe 17, a pump 30 (recovery unit), a valve 18 (second valve), a temperature sensor 22, a pressure sensor 23, and a controller 20 (control unit).

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.

  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 main 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 main pipe 15 constitutes a supply channel through which NH ₃ moves between the storage 11 and the heater 12.

The valve 16 is disposed in the main pipe 15. That is, the valve 16 is disposed 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 valve 16 is disposed at a position sufficiently away from the heater 12 that becomes high temperature during the exothermic reaction. As a result, the valve 16 is not easily affected by the heat of the heater 12.

The bypass pipe 17 connects the storage 11 side with respect to the valve 16 in the main pipe 15 and the heater 12 side with respect to the valve 16 in the main pipe 15. The bypass pipe 17 connects the storage 11 and the valve 16 in the main pipe 15 and the heater 12 and the valve 16 in the main pipe 15 so as to bypass the valve 16. That is, the bypass pipe 17 constitutes a bypass flow path for circulating NH ₃ so as to bypass the valve 16.

  Further, the connection position between the bypass pipe 17 and the heater 12 side of the main pipe 15 relative to the valve 16 is sufficiently separated from the heater 12. This is because the valve 18 is arranged at a position sufficiently away from the heater 12 that becomes high temperature during the exothermic reaction. As a result, the valve 18 is not easily affected by the heat of the heater 12.

The pump 30 is disposed in the bypass pipe 17. The pump 30 sucks NH ₃ remaining between the heater 12 and the valve 16 in the main pipe 15 in a state where the valve 16 is closed. Then, the pump 30 forcibly collects the sucked NH ₃ into the storage 11. The controller 20 controls the operation of the pump 30.

The valve 18 is disposed upstream of the pump 30 in the bypass pipe 17 (on the heater 12 side than the pump 30). The upstream side in the bypass pipe 17 refers to the upstream side in the direction in which NH ₃ flows through the bypass pipe 17 when NH ₃ is sucked by the pump 30. The valve 18 opens and closes the NH ₃ flow path that flows in the bypass pipe 17. For example, the valve 18 is an electromagnetic on-off valve. The controller 20 performs opening control and closing control of the valve 18.

  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 heater 12. The pressure sensor 23 detects the pressure in the heater 12 at regular time 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 pump operating unit 25, a collection amount acquisition unit 26, and a determination unit 27.

  The valve opening / closing unit 24 controls opening and closing of the valves 16 and 18. 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.

  Further, the valve opening / closing section 24 causes the valve 18 to be closed when performing the opening control of the valve 16. That is, when the valve 18 is in the open state, the valve opening / closing unit 24 stops the supply of current to the valve 18 and switches the valve 18 from the open state to the closed state. When the valve 18 is in the closed state, the valve opening / closing unit 24 keeps the supply of the current to the valve 18 stopped and maintains the valve 18 in the closed state.

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 main pipe 15, and the reactant 14 of the heater 12. (For example, MgBr ₂ ) and NH ₃ chemically react with each other and chemisorb (coordinate bond), and heat is generated from the reactant 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 open 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 main 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.

In the present embodiment, at the time of NH ₃ recovery through the main pipe 15, the opening / closing control of the valves 16, 18 by the valve opening / closing unit 24 and the operation control of the pump 30 by the pump operating unit 25 are performed. This is performed based on the value related to the recovery amount of NH ₃ acquired by H.26. 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, when the determination unit 27 determines that the NH ₃ recovery rate has exceeded the first recovery target value (first predetermined value), the valve opening / closing unit 24 controls the valve 16 to close and Open control. As a result, the flow of NH ₃ in the main pipe 15 is blocked, and NH ₃ can move through the bypass pipe 17. Here, the first recovery target value is a value that is 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 first recovery target value is set to, for example, about 80% in consideration of NH ₃ that remains in the heater 12 or the main pipe 15 without being recovered in the storage 11.

The pump operating unit 25 operates the pump 30 when the determination unit 27 determines that the NH ₃ recovery rate has exceeded the first recovery target value. That is, the pump operating unit 25 switches the pump 30 from the OFF state to the ON state. Thus, NH ₃ remaining between the heater 12 and the valve 16 in the main pipe 15 in a state where the valve 16 is closed is sucked by the pump 30 and supplied to the storage 11 side. That is, NH ₃ remaining between the heater 12 and the valve 16 in the main pipe 15 returns to the storage 11 through the bypass pipe 17 by being sucked by the pump 30, and the adsorbent 13 in the storage 11. It is physically adsorbed and recovered.

In the recovery of NH ₃ performed through the bypass pipe 17, for example, when the determination unit 27 determines that a predetermined time has elapsed since the pump 30 started to operate, the valve opening / closing unit 24 controls the valve 18 to close, and the pump is operated. The unit 25 stops the operation of the pump 30. The predetermined time is a value appropriately set by a user or the like, and is, for example, about 1 minute after the pump 30 starts to operate.

For example, when the determination unit 27 determines that the NH ₃ recovery rate has reached the second recovery target value (second predetermined value) before the predetermined time has elapsed since the pump 30 started to operate, the valve opening / closing unit 24 closes the valve 18, and the pump operating unit 25 stops the operation of the pump 30. Here, the second recovery target value is a value that is appropriately set by the user or the like, and is a value that is larger than the first recovery target value. The second collection target value is set to about 85%, for example. Therefore, when a predetermined time has elapsed at the latest after the pump 30 starts operating, the valve 18 is controlled to be closed and the operation of the pump 30 is stopped.

The recovery amount acquisition unit 26 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 26, map data shown in the graphs of FIGS. 2A and 2B is set in advance. The recovery amount acquisition unit 26 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 26 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 recovery amount acquisition unit 26 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 recovery amount acquisition unit 26 acquires the NH ₃ adsorption amount Y using the map data having the relationship shown by the graph of 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 26 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 during warm-up from the NH ₃ adsorption amount Y. The amount of NH ₃ recovered in the storage 11 is acquired. Furthermore, the recovery amount acquisition unit 26, the NH ₃ amount recovered, the amount of NH ₃ that is required to obtain the desired amount of heat in an exothermic reaction in the heater 12, that is, the amount of NH ₃ is moved to the heater 12 The NH ₃ recovery rate is obtained by dividing by (hereinafter also referred to as “total NH ₃ recovery amount”).

The determination unit 27 performs various determinations based on the NH ₃ recovery rate acquired by the recovery amount acquisition unit 26, and outputs the determination results to the valve opening / closing unit 24 and the pump operating unit 25. Specifically, the determination unit 27 determines whether or not the NH ₃ recovery rate exceeds the first recovery target value. The determination unit 27 determines whether or not a predetermined time has elapsed since the pump 30 started to operate. Further, the determination unit 27 determines whether or not the NH ₃ recovery rate has reached the second recovery target value before a predetermined time has elapsed since the pump 30 started to operate.

  Next, processing procedures of the valve opening / closing unit 24, the pump operating unit 25, and the determining unit 27 will be described with reference to FIG. FIG. 3 is a flowchart showing the processing procedure of the valve opening / closing unit 24, the pump operating unit 25, and the determination unit 27. In addition, the flowchart of FIG. 3 shows the processing procedure in the final stage of the regeneration reaction. In the following processing procedure, it is assumed that the valves 16 and 18 are in a closed state immediately before the warm-up during the operation of the engine 2 ends.

When the warm-up during the operation of the engine 2 is finished, the valve opening / closing part 24 opens the valve 16. Thereby, recovery of NH ₃ from the heater 12 through the main pipe 15 into the storage 11 is started. At the time of recovery of NH ₃ through the main pipe 15, first, the determination unit 27 determines that the NH ₃ recovery rate acquired by the recovery amount acquisition unit 26 is the first recovery target value (here, about 80%). It is determined whether or not it exceeds (S1). When the determination unit 27 determines that the NH ₃ recovery rate does not exceed the first recovery target value (S1; NO), the valve opening / closing unit 24 maintains the open state of the valve 16 and the closed state of the valve 18, The process of S1 is repeated.

When the determination unit 27 determines that the NH ₃ recovery rate has exceeded the first recovery target value (S1; YES), the valve opening / closing unit 24 closes the valve 16 and opens the valve 18 ( S2). That is, the valve opening / closing unit 24 stops supplying current to the valve 16 and supplies current to the valve 18. As a result, the flow of NH ₃ in the main pipe 15 is blocked, and the recovery of NH ₃ from the heater 12 through the main pipe 15 into the storage 11 is completed, and the NH ₃ can move through the bypass pipe 17.

Then, the pump operating unit 25 operates the pump 30 (S3). That is, the pump operating unit 25 switches the pump 30 from the OFF state to the ON state. Thus, NH ₃ remaining between the heater 12 and the valve 16 in the main pipe 15 (hereinafter also referred to as “residual NH ₃ ”) is sucked by the pump 30 and supplied to the storage 11 side. That is, recovery of residual NH ₃ using the pump 30 is started. Residual NH _{3 that} has passed through the bypass pipe 17 by suction of the pump 30 returns to the storage 11 and is physically adsorbed by the adsorbent 13 in the storage 11 and collected.

Subsequently, the determination unit 27 determines whether or not a predetermined time has elapsed since the pump 30 started to operate (S4). When the determination unit 27 determines that the predetermined time has elapsed (S4: YES), the valve opening / closing unit 24 closes the valve 18 (S5). That is, the valve opening / closing unit 24 stops the supply of current to the valve 18. Thereby, the flow of NH ₃ in the bypass pipe 17 is blocked. Then, the pump operating unit 25 stops the operation of the pump 30 (S6). That is, the pump operating unit 25 switches the pump 30 from the ON state to the OFF state. Thus, the recovery of the residual NH ₃ using the pump 30 is terminated.

When the determination unit 27 determines that the predetermined time has not elapsed (S4: NO), the determination unit 27 further sets the NH ₃ recovery rate to the second recovery target value (here, about 85%). It is determined whether or not (S7). When the determination unit 27 determines that the NH ₃ recovery rate has not reached the second recovery target value (S7; NO), the valve opening / closing unit 24 maintains the valve 18 in the open state, and repeats the process of S4.

When the determination unit 27 determines that the NH ₃ recovery rate has reached the second recovery target value (S7; YES), the process proceeds to S5 and S6. That is, the valve opening / closing unit 24 closes the valve 18 (S5), and the pump operating unit 25 stops the operation of the pump 30 (S6). Thus, the recovery of the residual NH ₃ using the pump 30 is terminated. Thus, the processing procedure of the valve opening / closing unit 24, the pump operating unit 25, and the determination unit 27 in the final stage of the regeneration reaction is completed.

As described above, according to the chemical heat storage device 10 according to the present embodiment, for example, after the valve 16 is closed in the final stage of the regeneration reaction, NH ₃ remains between the heater 12 and the valve 16 in the main pipe 15. Even in this case, the residual NH ₃ is sucked by the pump 30 and forcibly recovered to the storage 11. Therefore, a problem that the residual NH ₃ is again reacted with the reactive material 14 in the heater 12 is less likely to occur. As a result, a decrease in the amount of the reaction material 14 that reacts during the next exothermic reaction is suppressed, and a decrease in the exothermic performance during the next exothermic reaction is suppressed. Furthermore, pump 30, NH ₃ from for sucking residual NH ₃ in a state where the valve 16 is closed, the heater 12 inside regardless of the open or closed state of the valve 16 by operating the pump 30 at all times during the recovery of NH ₃ Compared with the case of directly sucking in, the operating time required for sucking in NH ₃ is shortened, and the power consumption is suppressed. As described above, it is possible to suppress a decrease in heat generation performance while suppressing power consumption.

Here, the valve 16 is disposed at a position sufficiently away from the heater 12 that becomes a high temperature during an exothermic reaction. In this case, the valve 16 is not easily affected by the heat of the heater 12, while the distance between the heater 12 and the valve 16 in the main pipe 15 becomes long, so that residual NH ₃ is likely to occur. According to the present embodiment, the residual NH ₃ can be sucked by the pump 30 and forcibly recovered to the storage 11. Therefore, while suppressing the influence of the heat of the heater 12 on the valve 16, the above-described problem that the heat generation performance is reduced by the residual NH ₃ can be solved.

In addition, according to the present embodiment, when the NH ₃ recovery rate exceeds the first recovery target value, the pump 30 operates, and therefore, until the NH ₃ recovery rate does not exceed the first recovery target value. The pump 30 is prevented from operating. As a result, the operation time of the pump 30 can be reliably shortened and power consumption can be reliably suppressed.

  In addition, according to the present embodiment, since the operation of the pump 30 is stopped when a predetermined time has elapsed after the pump 30 starts to operate, the operation time of the pump 30 can be further shortened and the power consumption can be further suppressed.

Further, according to the present embodiment, the pump is operated until the NH ₃ recovery rate reaches the second recovery target value, so that the remaining NH ₃ is sufficiently recovered in the storage 11. As a result, it is possible to reliably suppress a decrease in heat generation performance. Furthermore, even before the pump 30 a predetermined time elapses after starting to operate, because the operation of the pump 30 is stopped when the NH ₃ recovery reaches the second recovery target value, the residual NH ₃ in the storage 11 It is possible to prevent the pump 30 from operating until it has been sufficiently recovered, and to further reduce power consumption.

In addition, when two first supply channels and two second supply channels are provided in parallel as in a conventional chemical heat storage device, it functions as a supply channel that moves NH ₃ between the heater and the storage. Since there are two pipes in parallel, the volume of the pipe as a whole of the chemical heat storage device is increased and the pressure of NH ₃ in the heater is reduced as compared with the case where there is one pipe functioning as a supply flow path. As a result, there is a problem that the exothermic temperature of the reaction material is lowered. On the other hand, according to this embodiment, there is one main pipe 15 that functions as a supply flow path for moving NH ₃ between the heater 12 and the storage 11, and the bypass pipe 17 bypasses the valve 16. It is provided as follows. Therefore, compared with the case where there are two pipes functioning in parallel as in the prior art, the volume of the pipe as a whole of the chemical heat storage device 10 can be reduced. Accordingly, since it is possible to suppress a decrease in the pressure of the NH ₃ in the heater, it is possible to suppress the reduction of the heat generation temperature of the reaction material 14.

  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-described embodiment, the opening / closing control of the valves 16 and 18 and the operation control of the pump 30 are performed by the controller 20, but the present invention is not limited thereto, and may be performed manually or the like.

  In the said embodiment, although the pump 30 is used as a collection | recovery part, it is not restricted to this. For example, a compressor or the like may be used as the recovery unit.

  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. Further, the heat storage material in the case of NH ₃ reaction medium in the above embodiment has illustrated respectively the materials of the adsorbent, depending on the reaction medium used in the chemical heat storage device, the heat storage material, adsorbent suitable other materials 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. 4, 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 ... Main piping, 16 ... Valve (1st valve), 17 ... Bypass piping, 18 ... Valve ( (Second valve), 20... Controller (control unit), 30... Pump (collection unit).

Claims (4)

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;
Main piping connecting the reservoir and the reactor;
A first valve disposed in the main pipe and opening and closing a flow path of the reaction medium;
A bypass pipe connecting the reservoir side with respect to the first valve in the main pipe and the reactor side with respect to the first valve in the main pipe;
In the state where the bypass valve is disposed and the first valve is closed, the storage medium is sucked in the reaction medium remaining between the reactor and the first valve in the main pipe. A chemical heat storage device comprising: a recovery unit that forcibly recovers. A second valve that is disposed closer to the reactor than the recovery unit in the bypass pipe and opens and closes a flow path of the reaction medium;
A control unit that performs control of opening and closing of the first valve and the second valve, and control of operation of the recovery unit, and
The control unit obtains a value related to the recovery amount of the reaction medium recovered from the reactor to the reservoir, and closes the first valve when the value related to the recovery amount exceeds a first predetermined value. The chemical heat storage device according to claim 1, wherein the second valve is controlled to open and the recovery unit is operated.   The chemical heat storage according to claim 2, wherein the control unit closes the second valve and stops the operation of the recovery unit when a predetermined time has elapsed after the recovery unit has started to operate. apparatus.   When the value related to the recovered amount becomes a second predetermined value larger than the first predetermined value before the predetermined time has elapsed since the recovery unit started to operate, The chemical heat storage device according to claim 3, wherein the control is closed and the operation of the recovery unit is stopped.

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