JP7108161B2 - heat recovery system - Google Patents

Description

The present invention relates to heat recovery systems.

Binary power generation is known in which hot water or steam is used as a heat source to heat and evaporate a heat medium with a low boiling point to generate power. Binary power generation makes effective use of relatively low-temperature waste heat, and is also used in geothermal power generation, for example.

In recent years, attempts have been made to use waste heat generated in, for example, factories and facilities for binary power generation (see, for example, Patent Document 1).

JP 2017-129059 A

FIG. 8 is an explanatory diagram of equipment in which a binary power generation unit 91 (hereinafter referred to as "power generation unit 91") is applied to a heat treatment apparatus 90 for heat-treating (quenching) metal parts. This facility includes an oil tank 92 provided in a heat treatment device 90 , a power generation unit 91 and a heat exchanger 93 . A coolant 99 is stored in the oil tank 92 . The oil tank 92 and the heat exchanger 93 are connected by a primary pipe 94 , and the heat exchanger 93 and the power generation unit 91 are connected by a secondary pipe 95 . The heated processed product 100 is cooled by being immersed in the cooling liquid 99 of the oil tank 92, and heat treatment (quenching processing) is performed. This heat treatment temporarily increases the temperature of the cooling liquid 99 . A coolant 99 is caused to flow through the primary pipe 94 , and the heat (waste heat) of the flowing coolant 99 is transferred (heat exchanged) to the heat medium 98 flowing through the secondary pipe 95 in the heat exchanger 93 . The heat of the heat medium 98 causes the power generation unit 91 to generate power and cools the coolant 99 .

In this way, the cooling liquid 99 whose temperature has risen serves as a heat source, and the power generation unit 91 generates power.

In the heat treatment apparatus 90 as described above, the time interval (cycle time T in FIG. 9) for immersing the treated product 100 in the oil tank 92 is long (eg, 30 minutes), and depending on conditions such as the weight of the treated product 100, The time interval (cycle time T) changes. When the heated workpiece 100 is immersed in the oil tank 92, the temperature of the cooling liquid 99 rises, and for a predetermined time (Δt in FIG. 9), the temperature of the cooling liquid 99 exceeds a predetermined temperature A, enabling power generation. However, when the temperature of the coolant 99 eventually drops to a predetermined temperature A, power generation becomes impossible.

When the heat of the cooling liquid 99 of the heat treatment apparatus 90 is used for power generation, the temperature of the cooling liquid 99 varies depending on the processing conditions such as the heating temperature and weight of the workpiece 100, and also changes over time. If this change is irregular, power generation by the power generation unit 91 will become unstable, and there is a possibility that there will be many periods of time when the power generation unit 91 does not function. It should be noted that such a problem may similarly occur when the power generation unit 91 is applied to other equipment besides the heat treatment apparatus 90 as described above.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a heat recovery system that enables efficient power generation even when the temperature of waste heat obtained at a heat source changes.

The heat recovery system of the present invention includes a plurality of heat sources that increase the temperature of a first fluid by heat obtained by processing an article to be treated, and a plurality of heat sources through a primary flow path through which the first fluid flows. a heat exchanger that is connected to the first fluid and exchanges heat from the first fluid to the second fluid; and a valve mechanism for selecting a flow path that is provided in the primary flow path and connects the heat exchanger and the heat source. , a power generation unit that is connected to the heat exchanger via a secondary flow path through which the second fluid flows and generates power using the second fluid as an input, wherein the temperature of the first fluid in one of the heat sources is The timing of the rise differs from the timing of the temperature rise of the first fluid in the other heat source sections, and the valve mechanism operates according to the timing of the temperature rise of the first fluid in each of the plurality of heat source sections.

According to this heat recovery system, a plurality of heat source units share the power generation unit. The timing of the temperature rise of the first fluid differs between one heat source and the other heat source. Therefore, when the first fluid whose temperature has risen in one heat source is supplied to the heat exchanger, heat is exchanged from the first fluid to the second fluid, and the power generation unit generates electricity using the second fluid as input. . After that, even if the temperature of the one heat source drops and power generation becomes impossible, the first fluid whose temperature has risen in the other heat source is supplied to the heat exchanger, and the first fluid is supplied to the heat exchanger. Heat is exchanged between the two fluids, and the power generation unit can generate electricity using the second fluid as an input. In this way, by making the timing of the temperature rise of the first fluid different in the plurality of heat sources, the operation opportunities of the power generation unit increase. Therefore, power generation by the power generation unit is efficiently performed. It is also possible to intentionally shift the timing of starting the cycle of the heat source (heat treatment apparatus) on the side of the heat source (heat treatment apparatus).

Further, the primary flow path section includes a main flow path that connects the heat source section and the heat exchanger, a connection flow path that connects the heat source sections and enables the movement of the first fluid between the heat source sections, and the valve mechanism causes the first fluid to flow to the other heat source through the connection channel when the temperature of the first fluid in one of the heat sources rises, and the first fluid flows to the It is preferable to include a valve for switching the flow path to flow to the heat exchanger via another heat source.
According to this configuration, when the temperature of the first fluid in one heat source rises, the first fluid flows to the other heat source through the connection flow path, and the first fluid passes through the other heat source. The flow path is switched to flow through to the heat exchanger. On the other hand, when the temperature of the first fluid in the other heat source section rises, the first fluid flows to the one heat source section through the connection flow path, and the first fluid flows into the one heat source section. is switched to flow through the heat exchanger.
As in the above configuration, the heat source portions are connected to each other by the connection flow path, so that these heat source portions can be regarded as one heat source portion, and the capacity of the first fluid serving as the heat source is increased. Therefore, although the temperature rise of the first fluid due to the heat obtained by processing the object is mitigated, the increased temperature of the first fluid becomes less likely to decrease. Therefore, it is possible to lengthen the time during which the power generation unit can generate power. Furthermore, as described above, by making the timing of the temperature rise of the first fluid different in the plurality of heat sources, the operation opportunities of the power generation unit increase. Therefore, power generation by the power generation unit is performed more efficiently.

The heat recovery system of the present invention includes a plurality of heat sources that increase the temperature of a first fluid by heat obtained by processing an article to be treated, and a plurality of heat sources through a primary flow path through which the first fluid flows. a heat exchanger that is connected to the first fluid and exchanges heat from the first fluid to the second fluid; and a valve mechanism for selecting a flow path that is provided in the primary flow path and connects the heat exchanger and the heat source. and a power generation unit that is connected to the heat exchanger via a secondary flow path through which the second fluid flows and generates power using the second fluid as an input, wherein the primary flow path is connected to the heat source and the a main flow path that connects the heat exchanger and a connection flow path that connects the heat sources and enables the movement of the first fluid between the heat sources; When the temperature of the first fluid rises, the first fluid flows through the connection channel to the other heat source, and the first fluid flows to the heat exchanger via the other heat source. including a valve for switching the flow path.

According to this heat recovery system, the heat sources can be regarded as one heat source by connecting the heat sources with the connection channel, and the capacity of the first fluid serving as the heat source is increased. Therefore, although the temperature rise of the first fluid due to the heat obtained by processing the object is mitigated, the increased temperature of the first fluid becomes less likely to decrease. Therefore, it is possible to lengthen the time during which the power generation unit can generate power. Therefore, power generation by the power generation unit is efficiently executed.

Also, the power generation unit is preferably a binary power generation unit, in which case relatively low-temperature waste heat can be effectively utilized.

ADVANTAGE OF THE INVENTION According to this invention, even when the temperature of the waste heat obtained from a heat-source part changes, for example, it becomes possible to perform an electric power generation efficiently.

It is a top view showing an example of a heat recovery system. It is explanatory drawing of an oil tank, a heat exchanger, and an electric power generation unit. It is explanatory drawing of an oil tank, a heat exchanger, and an electric power generation unit. It is explanatory drawing of an oil tank, a heat exchanger, and an electric power generation unit. It is a graph which shows the time change of the temperature in each chamber, such as a quenching chamber for heat treatment by a No. 1 furnace and a No. 2 furnace. FIG. 4 is an explanatory diagram of the relationship between the temperature of coolant in each of No. 1 and No. 2 furnaces and whether or not the power generation unit can generate power. FIG. 4 is an explanatory diagram of the relationship between the temperature of coolant in each of No. 1 and No. 2 furnaces and whether or not the power generation unit can generate power. 1 is a conventional explanatory diagram of a facility in which a binary power generation unit is applied to a heat treatment apparatus for heat-treating metal parts; FIG. FIG. 10 is an explanatory diagram of the relationship between the temperature of the cooling liquid and whether or not the power generation unit can generate power in the conventional technology.

[Regarding the configuration of the heat recovery system]
FIG. 1 is a plan view showing an example of a heat recovery system. This heat recovery system 10 is a system that generates power by means of a power generation unit 14 using waste heat from a heat treatment device 12 for heat-treating metal parts. Examples of the metal parts include mechanical parts such as rolling bearing rings, shafts, and pins. The heat treatment is quenching treatment. For heat treatment (see FIG. 2), the heated metal part 7 (hereinafter referred to as the "treated product 7") is immersed in a cooling liquid (quenching oil) 18 in an oil tank 16 provided in the heat treatment apparatus 12, Cooled. At this time, the temperature of the coolant 18 rises. Therefore, the heat of the coolant 18 is used for power generation. That is, the oil tank 16 functions as a heat source, and the cooling liquid 18 serves as a heat medium (first fluid) on the primary side. The heat of the coolant 18 is transferred to the medium (second fluid) 19 on the secondary side by the heat exchanger 20, and the power generation unit 14 generates power. FIG. 2 is an explanatory diagram of the oil tank 16, the heat exchanger 20, and the power generation unit 14. As shown in FIG. In addition, the same symbols (reference numbers) are attached to the same constituent elements in each drawing, and redundant description is omitted. In this embodiment (see FIG. 2), a plurality of processed products 7 are stored in a basket 8, and the basket 8 is vertically moved by an actuator (not shown).

The heat recovery system 10 shown in FIG. 1 includes two thermal processors 12 . The upper heat treatment apparatus 12 in FIG. 1 is referred to as "No. 1 Furnace 12a", and the lower heat treatment apparatus 12 is referred to as "No. 2 Furnace 12b". The No. 1 furnace 12a and the No. 2 furnace 12b have the same configuration. Each of the No. 1 furnace 12a and the No. 2 furnace 12b has a first purge chamber 81, a first preheating chamber 82, a second preheating chamber 83, a carburizing/diffusion chamber, from the upstream side (the left side in FIG. 1) in the traveling direction of the workpiece 7. A chamber 84 , a cooling chamber 85 , a soaking chamber 86 , a quenching chamber 87 and a second purge chamber 88 are provided. An oil tank 16 is provided in the quenching chamber 87 . Since the heat recovery system 10 includes two thermal processors 12 , the heat recovery system 10 includes two oil tanks 16 . The oil tank 16 of the No. 1 furnace 12a is called the "first oil tank 16a", and the oil tank 16 of the No. 2 furnace 12b is called the "second oil tank 16b".

In FIG. 2, the heat recovery system 10 includes a heat exchanger 20, a power generation unit 14, and a valve mechanism 22 in addition to an oil tank 16 (16a, 16b) as a heat source. Additionally, the heat recovery system 10 includes a primary flow path section 24 and a secondary flow path section 26 . The primary flow path part 24 connects the oil tank 16 (16a, 16b) and the heat exchanger 20, and passes the cooling liquid 18 therethrough. The secondary flow path part 26 connects the heat exchanger 20 and the power generation unit 14 and allows the heat medium 19 on the secondary side to flow. The secondary heat transfer medium 19 can be a liquid with a relatively low boiling point.

A coolant 18 is stored in the oil tank 16 . As described above, the heated workpiece 7 is immersed in the cooling liquid 18, so that the workpiece 7 is heat-treated (quenched). At this time, the temperature of the coolant 18 rises. That is, the temperature of the cooling liquid 18 rises due to the heat obtained by the heat treatment of the workpiece 7 .

The heat exchanger 20 is connected to the two oil tanks 16a and 16b via a primary flow path portion 24 through which the coolant 18 flows. In the heat exchanger 20, the heat of the coolant 18 is transferred to the heat medium 19 on the secondary side. That is, the heat exchanger 20 exchanges heat from the coolant 18 to the heat medium 19 on the secondary side.

The primary channel portion 24 includes a main channel 28 and a connecting channel 30 . The main flow path 28 connects each of the oil tanks 16 a and 16 b and the heat exchanger 20 . The connection channel 30 connects the oil tanks 16a and 16b and allows the coolant 18 to move between the oil tanks 16a and 16b. The main flow path 28 includes a first pipe 31 , a second pipe 32 and a third pipe 33 . The first pipe 31 connects the first oil tank 16a and the second oil tank 16b. The first pipe 31 is provided with a first valve 34 and a second valve 35 that can be opened and closed. The second pipe 32 is a pipe parallel to the first pipe 31 and connects the first oil tank 16a and the second oil tank 16b. The second pipe 32 is provided with a third valve 36 and a fourth valve 37 that can be opened and closed. The third pipe 33 connects the first pipe 31 and the second pipe 32 . The third pipe 33 is provided with a pump 39 for circulating the coolant 18 and a heat exchanger 20 . One end side of the third pipe 33 is connected to the flow path between the first valve 34 and the second valve 35 in the first pipe 31, and the other end side of the third pipe 33 is connected to the second pipe 32 , it is connected to a flow path between a third valve 36 and a fourth valve 37 .

The connection channel 30 is configured by a pipe, and is provided with an opening/closing fifth valve 38 . Each of the valves 34, 35, 36, 37, 38 opens and closes based on a command signal output from a control device (not shown). The control of the opening/closing operation may be performed by a control device that controls the operation (heat treatment control) of the No. 1 furnace 12a and the No. 2 furnace 12b. The secondary flow path section 26 includes a fourth pipe 40 and a pump 41 for circulating the heat medium 19 on the secondary side between the heat exchanger 20 and the power generation unit 14 .

The valve mechanism 22 is composed of the first valve 34 , the second valve 35 , the third valve 36 , the fourth valve 37 and the fifth valve 38 . The valve mechanism 22 is provided in the primary channel portion 24 .

When the fifth valve 38 is closed, the first valve 34 and the third valve 36 are open, and the second valve 35 and the fourth valve 37 are closed, the coolant 18 in the first oil reservoir 16a returns to the first oil tank 16a via part of the second pipe 32, third pipe 33, and part of the first pipe 31. This flow is generated by pump 39 and coolant 18 passes through heat exchanger 20 . This flow of the cooling liquid 18 is referred to as "circulating flow of the first oil tank 16a".

On the other hand, when the fifth valve 38 is closed, the first valve 34 and the third valve 36 are closed, and the second valve 35 and the fourth valve 37 are open, the second oil tank The coolant 18 at 16b returns to the second oil tank 16b via a portion of the second pipe 32, a third pipe 33, and a portion of the first pipe 31. This flow is generated by pump 39 and coolant 18 passes through heat exchanger 20 . This flow of the cooling liquid 18 is referred to as "circulating flow of the second oil tank 16b".

Thus, the valve mechanism 22 functions to select the flow path connecting the heat exchanger 20 and the oil tanks 16a, 16b. In other words, the valve mechanism 22 selects the oil tank (16a or 16b) connected to the heat exchanger 20 from the two oil tanks 16a and 16b. Specifically, the valve mechanism 22 has a first function of selecting one of the circulating flow of the first oil tank 16a and the circulating flow of the second oil tank 16b. The configuration of the primary flow path portion 24 for obtaining the circulation flow of the first oil tank 16a and the circulation flow of the second oil tank 16b may be other than the illustrated construction. In addition to the first function, the valve mechanism 22 has the following second function.

As shown in FIG. 3, when the fifth valve 38 is open, the first valve 34 and the fourth valve 37 are open, and the second valve 35 and the third valve 36 are closed, The cooling liquid 18 in the first oil tank 16a flows to the second oil tank 16b through the connecting flow path 30, passes through part of the second pipe 32, third pipe 33, and part of the first pipe 31 to the first Return to oil tank 16a. This flow is generated by pump 39 and coolant 18 passes through heat exchanger 20 . This flow of the cooling liquid 18 is referred to as "the flow of the first system".

In contrast, as shown in FIG. 4, the fifth valve 38 is open, the second valve 35 and third valve 36 are open, and the first valve 34 and fourth valve 37 are closed. When in the state, the coolant 18 in the second oil tank 16b flows to the first oil tank 16a through the connecting channel 30, and passes through part of the second pipe 32, third pipe 33, and part of the first pipe 31. and return to the second oil tank 16b. This flow is generated by pump 39 and coolant 18 passes through heat exchanger 20 . This flow of the cooling liquid 18 is referred to as the "flow of the second system".

Thus, the valve mechanism 22 functions to select the flow path connecting the heat exchanger 20 and the oil tanks 16a, 16b. Specifically, the valve mechanism 22 has a second function of selecting one of the flow of the first system and the flow of the second system. The configuration of the primary flow path portion 24 for obtaining the flow of the first system and the flow of the second system may be other than the illustrated configuration.

In each of Figures 2, 3 and 4, the power generation unit 14 is a binary power generation unit. The power generation unit 14 is connected to the heat exchanger 20 via a secondary flow path portion 26 through which the heat medium 19 on the secondary side flows. The power generation unit 14 generates power using the heat medium 19 as an input. The power generation unit 14 generates power according to the temperature of the heat medium 19 on the secondary side. That is, the power generation unit 14 can generate power when the temperature of the heat medium 19 is equal to or higher than the predetermined temperature, and cannot generate power when the temperature of the heat medium 19 is lower than the predetermined temperature. That is, when the coolant 18 that exchanges heat with the heat medium 19 has a temperature equal to or higher than a specified temperature, the power generation unit 14 can generate power. cannot generate power.

[About power generation operation (Part 1)]
A power generation operation performed by the heat recovery system 10 having the above configuration will be described. FIG. 5 is a graph showing temperature changes over time in each chamber such as the quenching chamber 87 (see FIG. 1) for heat treatment by the No. 1 furnace 12a and the No. 2 furnace 12b. The upper side of FIG. 5 is the graph for the No. 1 furnace 12a, and the lower side is the graph for the No. 2 furnace 12b. In each of the No. 1 furnace 12a and the No. 2 furnace 12b, the treated product 7 is heated at a carburizing temperature of about 950° C. in the carburizing/diffusion chamber 84, and then the treated product 7 is heated to a quenching temperature of about 850° C. in the quenching chamber 87. It is quenched by being immersed in the cooling liquid 18 in the oil bath 16 (quenching). As shown in FIG. 5, the time (timing) at which the rapid cooling of the workpiece 7 is started from the quenching temperature differs between the No. 1 furnace 12a and the No. 2 furnace 12b. FIG. 5 shows a case where rapid cooling in the No. 2 furnace 12b is started with a delay of time Δt1 from the start of rapid cooling in the No. 1 furnace 12a. Further, in each of the No. 1 furnace 12a and the No. 2 furnace 12b, the heat treatment of the workpiece 7 is repeatedly performed at a predetermined cycle time. This cycle time may change depending on the weight of the workpiece 7, for example, instead of being constant.

FIG. 6 is an explanatory diagram of the relationship between the temperature of the coolant 18 in each of the No. 1 furnace 12a and the No. 2 furnace 12b and whether or not the power generation unit 14 can generate power. As shown in FIG. 6, after a delay of time Δt1 from the start of quenching in the No. 1 furnace 12a (time t0), the quenching in the No. 2 furnace 12b is started, resulting in the second oil tank of the No. 2 furnace 12b. The start of the temperature rise of the cooling liquid 18 in 16b is delayed by time Δt1 (from the start time t0) from the start of the temperature rise of the cooling liquid 18 in the first oil tank 16a of the No. 1 furnace 12a. This time Δt1 is called "delay time Δt1".

After time t0, the temperature of the coolant 18 in the first oil tank 16a rises to a specified temperature A or higher, and heat is exchanged from the coolant 18 to the heat medium 19 on the secondary side in the heat exchanger 20. , the power generation unit 14 is enabled to generate power. For this reason, in FIG. 2, the second valve 35, the fourth valve 37 and the fifth valve 38 are closed and the first valve 34 and the third valve 36 are open. In other words, the flow of the coolant 18 is referred to as the "circulation flow of the first oil tank 16a". In this case, in FIG. 6, the temperature of the coolant 18 in the first oil tank 16a rises to a certain value and then falls. The power generation unit 14 can generate power for the duration Δt2 until the temperature becomes lower than the specified temperature A. In this embodiment, the delay time Δt1 is set longer than the duration Δt2. Note that the delay time Δt1 may be the same as the duration Δt2, or may be shorter than the duration Δt2.

In the case of FIG. 6, power generation becomes impossible at time Δt3, which is the difference between delay time Δt1 and duration Δt2. However, after a delay time Δt1 from the start of the temperature rise of the cooling liquid 18 in the first oil tank 16a (time t0), the temperature of the cooling liquid 18 in the second oil tank 16b rises to a specified temperature A or higher, and this cooling Heat is exchanged from the liquid 18 to the heat medium 19 on the secondary side in the heat exchanger 20, so that the power generation unit 14 can generate power. For this reason, in FIG. 2, the valve opening/closing operation is performed in the valve mechanism 22, the second valve 35 and the fourth valve 37 are opened (from the closed state), and the first valve 34 and the third valve 36 are opened (from the closed state). state) to the closed state. Note that the fifth valve 38 remains closed. In other words, the flow of the coolant 18 is referred to as the "circulation flow of the second oil tank 16b".

In FIG. 6, the temperature of the coolant 18 in the second oil tank 16b rises to a certain value and then drops. The power generation unit 14 can generate power for the duration Δt4 until the temperature becomes lower than the specified temperature A. After the duration Δt4, at time Δt5, the temperature of the cooling liquid 18 in the second oil tank 16b becomes less than the specified temperature A, and power generation becomes impossible. However, in the No. 1 furnace 12a, in the next cycle, That is, after the cycle time T has elapsed from time t0, another treated product 7 is immersed in the first oil tank 16a, and the waste heat of the first furnace 12a enables the power generation unit 14 to generate power again. For this reason, in FIG. 2, the valve opening/closing operation in the valve mechanism 22 is performed. After that, the above operation is repeatedly executed.

Thus, in the power generation operation (Part 1) performed by the heat recovery system 10, the timing of the temperature rise of the cooling liquid 18 in the first oil tank 16a, which is one heat source, is the same as that in the second oil tank 16b, which is another heat source The operation control of the No. 1 furnace 12a (the first oil tank 16a) and the No. 2 furnace 12b (the second oil tank 16b) is performed so that the temperature rise timing of the coolant 18 is different. The valve mechanism 22 operates according to the timing of temperature rise of the coolant 18 in each of the two oil tanks 16a and 16b.

According to the power generation operation (part 1), the two oil tanks 16a and 16b share the power generation unit 14. FIG. The timing of temperature rise of the coolant 18 differs between the first oil tank 16a and the second oil tank 16b. Therefore, when the cooling liquid 18 whose temperature has risen in the first oil tank 16a is supplied to the heat exchanger 20, heat is exchanged from the cooling liquid 18 to the heat medium 19 on the secondary side, and this heat medium 19 is used as an input. The power generation unit 14 generates power. Thereafter, even if the temperature of the first oil tank 16a drops and power generation becomes impossible, the coolant 18 whose temperature has risen in the second oil tank 16b, which is separate from the first oil tank 16a, is supplied to the heat exchanger 20. . Heat is exchanged from the coolant 18 to the heat medium 19 on the secondary side, and the power generation unit 14 can generate power using the heat medium 19 as an input. Thus, by making the temperature rise timing of the coolant 18 different between the two oil tanks 16a and 16b, the operation opportunities of the power generation unit 14 increase. Specifically (see FIG. 6), the cycle time T is assumed to be 30 minutes, and the duration Δt2 (Δt4) during which the power generation unit 14 can generate power is assumed to be 10 minutes. In the conventional example shown in FIG. 9, power can be generated for ⅓ of the cycle time T (10 minutes), and power cannot be generated for the remaining ⅔ of the time (20 minutes). On the other hand, according to the power generation operation (part 1) shown in FIG. ) cannot generate electricity. As described above, power generation by the power generation unit 14 is efficiently performed.

[About power generation operation (Part 2)]
The heat recovery system 10 having the above configuration can perform a power generation operation different from the above (part 1). The explanation is given below. As described above (see FIG. 3), the primary flow path portion 24 includes the main flow path 28 connecting the first oil tank 16a and the second oil tank 16b to the heat exchanger 20, and the first oil tank 16a and the second oil tank 16b to permit the movement of coolant 18 between the first oil reservoir 16a and the second oil reservoir 16b.

As shown in FIG. 3, when the heated workpiece 7 is immersed in the cooling liquid 18 in the first oil tank 16a, the valve mechanism 22 causes the flow of the cooling liquid 18 to change to the "flow of the first system". Therefore, opening and closing of the valves 34 to 38 are controlled. As a result, the temperature of the coolant 18 in the first oil tank 16a first rises. In this case, the coolant 18 in the first oil tank 16a flows through the connecting channel 30 to the second oil tank 16b, and the coolant 18 flows to the heat exchanger 20 via the second oil tank 16b. Then, heat is exchanged with the heat medium 19 on the secondary side in the heat exchanger 20, and the power generation unit 14 can generate power.

On the other hand, as shown in FIG. 4, when the heated workpiece 7 is immersed in the cooling liquid 18 in the second oil tank 16b, the valve mechanism 22 controls the flow of the cooling liquid 18 to the second system. The opening and closing of valves 34-38 are controlled in order to "flow". As a result, the temperature of the coolant 18 in the second oil tank 16b first rises. In this case, the coolant 18 in the second oil tank 16b flows to the first oil tank 16a through the connecting channel 30, and the coolant 18 flows to the heat exchanger 20 via the first oil tank 16a. Then, heat is exchanged with the heat medium 19 on the secondary side in the heat exchanger 20, and the power generation unit 14 can generate power.

3 and 4, the first oil tank 16a and the second oil tank 16b are connected by the connection flow path 30, so that The two oil tanks 16b can be regarded as one oil tank, and the capacity of the cooling liquid 18 as a heat source is increased. For this reason, the temperature rise of the cooling liquid 18 due to the heat obtained by heat-treating the workpiece 7 is moderated as compared with the case (1) (see FIG. 6), but the increased cooling liquid 18 It becomes difficult for the temperature to drop. That is, the time (Δt2, Δt4 in FIG. 6) during which the temperature of the cooling liquid 18 is equal to or higher than the specified temperature A becomes longer. Therefore, it is possible to lengthen the time during which the power generation unit 14 can generate power.

[About power generation operation (Part 3)]
The heat recovery system 10 having the above configuration can perform power generation operations different from the above (1) and (2). The explanation is given below. In the power generation operation (Part 3), as in the case of (Part 1), the timing of the temperature rise of the cooling liquid 18 in the first oil tank 16a and the timing of the temperature rise of the cooling liquid 18 in the second oil tank 16b must be different. Let Along with this, as in the case of (2) above, at the timing when the temperature of the cooling liquid 18 in the first oil tank 16a rises, the cooling liquid 18 in the first oil tank 16a flows through the connecting flow path 30 to the second oil tank 16b. , the flow path in the primary flow path portion 24 is switched by the valve mechanism 22 so that the coolant 18 flows to the heat exchanger 20 via the second oil tank 16b. On the other hand, at the timing when the temperature of the cooling liquid 18 in the second oil tank 16b rises, the cooling liquid 18 in the second oil tank 16b flows to the first oil tank 16a through the connecting passage 30, and the cooling liquid 18 flows into the first oil tank 16a. The valve mechanism 22 switches the flow path in the primary flow path section 24 so that the heat flows to the heat exchanger 20 via the .

By connecting the first oil tank 16a and the second oil tank 16b via the connection flow path 30 as described in (Part 2) above, the oil tanks 16a and 16b can be regarded as one oil tank, and the cooling liquid 18 serving as a heat source. capacity increases. Therefore, as shown in FIG. 7, the temperature rise of the cooling liquid 18 due to the heat obtained by processing the workpiece 7 is moderated, but the temperature of the cooling liquid 18 that has risen is less likely to decrease. Therefore, it is possible to lengthen the time (duration Δt2, Δt4) during which the power generation unit 14 can generate power. Furthermore, as in (Part 1) above, by making the temperature rise timing of the cooling liquid 18 different between the two oil tanks 16a and 16b, the operation opportunities of the power generation unit 14 increase. FIG. 7 is an explanatory diagram of the relationship between the temperature of the coolant 18 in each of the No. 1 reactor 12a and the No. 2 reactor 12b and whether or not the power generation unit 14 can generate power in the power generation operation (part 3). .

In the power generation operation (Part 3), the duration Δt2 during which power can be generated from the waste heat of the No. 1 furnace 12a is lengthened. Therefore, compared to the power generation operation (1) shown in FIG. 6, the time Δt3 during which power generation is impossible is shortened (eliminated). Then, the flow path in the primary flow path section 24 is switched by the valve mechanism 22 so as to enable power generation using the waste heat of the No. 2 furnace 12b before power generation becomes impossible due to the waste heat of the No. 1 furnace 12a. . That is, before power generation becomes impossible due to the waste heat of the No. 1 furnace 12a (or when power generation becomes impossible), the flow of the cooling liquid 18 changes from the above-mentioned "flow of the first system" to the above-mentioned "flow of the second system." changed to "flow". Then, following the duration time Δt2 in FIG. 7, power generation becomes possible from the waste heat of the No. 2 reactor 12b. Moreover, the duration Δt4 during which power can be generated from the waste heat of the No. 2 furnace 12b is lengthened. Therefore, compared to the power generation operation (1) shown in FIG. 6, the time Δt5 during which power generation is impossible is shortened (eliminated). Before the waste heat of the No. 2 furnace 12b makes it impossible to generate power (or when it becomes impossible to generate power), the valve mechanism 22 controls the primary flow so that the waste heat of the No. 1 furnace 12a can generate power. The channel in the channel portion 24 is switched. That is, before power generation becomes impossible due to the waste heat of the No. 1 furnace 12a (or when power generation becomes impossible), the flow of the cooling liquid 18 is changed from the above-mentioned "flow of the second system" to the above-mentioned "flow of the first system." changed to "flow".

According to the power generation operation (part 3) shown in FIG. 7, power generation is possible in the entire time of each cycle time T. As described above, power generation by the power generation unit 14 is efficiently performed.

[Regarding the heat recovery system 10 of the present embodiment]
In FIG. 1, in a heat treatment apparatus 12 for heat-treating a workpiece 7, conditions for heat treatment may change from moment to moment. Therefore, the temperature of the waste heat obtained in the oil tanks 16a and 16b becomes non-stationary. However, according to the power generation operations (part 2) and (part 3) performed by the heat recovery system 10 of the present embodiment, the waste heat can be leveled as much as possible and the waste heat can be efficiently used for power generation. .

Regarding the power generation operation (part 1) performed by the heat recovery system 10 of the present embodiment (see FIG. 6), the temperature rise of the cooling liquid 18 in the second oil tank 16b starts when the temperature of the cooling liquid 18 in the first oil tank 16a starts to rise. The time Δt1 is delayed from the start of the temperature rise (time t0), and this time Δt1 has been described as the “delay time Δt1”. As described above, since the temperature of the waste heat obtained in the oil tanks 16a and 16b is unsteady, this delay time Δt1 is not constant, and the delay time Δt1 may be changed. That is, the valve mechanism 22 changes the timing of switching the flow of the cooling liquid 18 between the "circulation flow of the first oil tank 16a" and the "circulation flow of the second oil tank 16b" in the first oil tank 16a and the second oil tank 16b. It may be variable according to the temperature of the coolant 18 .

In the above embodiment, the case where two heat treatment apparatuses 12 share one power generation unit 14 has been described, but the number of heat treatment apparatuses 12 may be more than two, and may be three or more.

The heat treatment apparatus 12 may be other than the continuous carburizing and quenching furnace described with reference to FIG. 1, and may be, for example, a batch type carburizing and quenching furnace. Moreover, the combination of a plurality of heat treatment apparatuses 12 may be a combination of a continuous carburizing and quenching furnace and a batch carburizing and quenching furnace.
The carburizing and quenching furnace has been described above as an example, but the present invention is not limited to this. The cooling fluid may be oil, water, polymer, or the like. In addition to the cooling liquid, cooling gas may be used. In addition, the equipment is not limited to carburizing and quenching furnaces, but heat treatment furnaces having quenching tanks such as quenching furnaces, carbonitriding quenching furnaces, vacuum carburizing and quenching furnaces, and vacuum quenching furnaces. good too.
Further, in the embodiment of FIG. 1, the case where the waste heat of the oil tank 16 in the quenching chamber 87 is used for power generation has been described, but the heat of the regenerative burner exhaust gas in the preheating chamber 82 (83) and the heat of the cooling tube in the cooling chamber 85 are used. It may be used as a heat source. In this case, the preheating chamber 82 (83) (or cooling chamber 85) serves as a heat source, and a part of the preheating chamber 82 (83) (or cooling chamber 85) of the No. 1 furnace 12a and the preheating chamber 82 of the No. 2 furnace 12b (83) (or a part of the lowering chamber 85) is connected by the connecting channel 30 or the like.

In the above-described embodiment, the case where the power generation unit 14 is combined with the heat treatment apparatus 12 has been described, but it may be combined with equipment other than the heat treatment apparatus 12 . When power is generated using waste heat obtained from facilities such as factories and heat treatment equipment 12, the waste heat may be in a high temperature range or a low temperature range. can be stably recovered and power can be generated efficiently.

The embodiments disclosed this time are illustrative in all respects and are not restrictive. The scope of rights of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope of equivalents to the configurations described in the claims.

7: Metal parts (processed product) 10: Heat recovery system 12: Heat treatment equipment 14: Power generation unit 16: Oil tank (heat source part) 16a: First oil tank 16b: Second oil tank 18: Coolant (first fluid) 19: Heat medium (second fluid)
20: Heat exchanger 22: Valve mechanism 24: Primary flow path part 26: Secondary flow path part 28: Main flow path 30: Connection flow path 34: First valve 35: Second valve 36: Third valve 37: Fourth Valve 38: fifth valve

Claims (4)

a plurality of heat source units that increase the temperature of the first fluid by heat obtained by processing the workpiece;
a heat exchanger that is connected to the plurality of heat source portions via the primary flow path portion through which the first fluid flows and performs heat exchange from the first fluid to the second fluid;
a valve mechanism for selecting a flow path that is provided in the primary flow path and connects the heat exchanger and the heat source;
a power generation unit that is connected to the heat exchanger via a secondary flow path through which the second fluid flows and generates power using the second fluid as an input;
with
The timing of the temperature rise of the first fluid in one of the heat sources is different from the timing of the temperature rise of the first fluid in the other heat sources, and the timing of the temperature rise of the first fluid in each of the plurality of heat sources is different. A heat recovery system in which the valve mechanism operates according to timing. The primary flow path includes a main flow path that connects the heat source and the heat exchanger, and a connection flow that connects the heat sources and allows the first fluid to move between the heat sources. ,
In the valve mechanism, when the temperature of the first fluid in one of the heat source parts rises, the first fluid flows to the other heat source part through the connection flow path, and the first fluid flows to the other heat source. 2. The heat recovery system of claim 1, including a valve for switching a flow path to flow through a section to the heat exchanger. a plurality of heat source units that increase the temperature of the first fluid by heat obtained by processing the workpiece;
a heat exchanger that is connected to the plurality of heat source portions via the primary flow path portion through which the first fluid flows and performs heat exchange from the first fluid to the second fluid;
a valve mechanism for selecting a flow path that is provided in the primary flow path and connects the heat exchanger and the heat source;
a power generation unit that is connected to the heat exchanger via a secondary flow path through which the second fluid flows and generates power using the second fluid as an input;
with
The primary flow path includes a main flow path that connects the heat source and the heat exchanger, and a connection flow that connects the heat sources and allows the first fluid to move between the heat sources. ,
In the valve mechanism, when the temperature of the first fluid in one of the heat source parts rises, the first fluid flows to the other heat source part through the connection flow path, and the first fluid flows to the other heat source. a valve for switching the flow path to flow through the heat exchanger to the heat exchanger;
heat recovery system. A heat recovery system according to any one of claims 1 to 3, wherein the power generation unit is a binary power generation unit.

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