Heat recovery device

Abstract

To provide a heat recovery device that prevents performance degradation and reduces operating costs. [Solution] The heat recovery device 10 includes a dirt recovery tank 11 that is capable of storing water and into which exhaust heat air from the equipment is introduced; a first supply unit that pumps up the water stored in the dirt recovery tank 11 and supplies it to the exhaust heat air passing through the dirt recovery tank 11; one or more hot water supply tanks 12, 13, 14 that are capable of storing water and into which the exhaust heat air that has passed through the dirt recovery tank 11 is introduced; and a second supply unit that is provided individually in correspondence to each of the one or more hot water supply tanks 12, 13, 14 and pumps up the water stored in the hot water supply tanks 12, 13, 14 and supplies it to the exhaust heat air passing through the second tank.

Description

Technical Field

[0001] One aspect of the present invention relates to a heat recovery device.

Background Art

[0002] As a method of utilizing the heat of factory exhaust heat air discharged from factory facilities and the like, a method of recovering heat using a heat exchanger is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, the factory exhaust heat air contains impurities such as dust and tar components together with thermal energy. When heat is recovered by the heat exchanger as described above, the heat exchanger is clogged by the above impurities, and problems such as a decrease in the performance of the heat exchanger and an increase in the cost related to the maintenance or replacement of the heat exchanger arise.

[0005] One aspect of the present invention has been made in view of the above circumstances, and relates to a heat recovery device in which performance degradation is prevented and operating costs are reduced.

Means for Solving the Problems

[0006] [1] A heat recovery device according to one aspect of the present invention comprises: a first tank provided to store water and into which exhaust heat air from the equipment is introduced; a first supply unit that pumps up the water stored in the first tank and supplies it to the exhaust heat air passing through the first tank; one or more second tanks provided to store water and into which the exhaust heat air that has passed through the first tank is introduced; and a second supply unit provided individually in correspondence to each of the one or more second tanks, that pumps up the water stored in the second tanks and supplies it to the exhaust heat air passing through the second tanks.

[0007] With this configuration, in the first tank, which is the upstream tank in the exhaust heat air flow path, water is supplied to the exhaust heat air, and impurities in the exhaust heat air are removed (water containing impurities is stored in the first tank). Then, in the second tank, water is supplied to the exhaust heat air from which impurities have been removed to some extent, making it possible to recover heat with clean air and provide hot water. Thus, according to one aspect of the present invention, heat can be recovered (hot water can be provided) without causing problems such as blockage of the heat exchanger due to impurities, which was a problem in the past. In other words, according to one aspect of the present invention, it is possible to provide a heat recovery device that prevents performance degradation and reduces operating costs.

[0008] [2] The heat recovery apparatus described in [1] above comprises a plurality of second tanks, each comprising an upstream tank adjacent to the first tank into which exhaust heat air that has passed through the first tank is introduced, and a downstream tank adjacent to the upstream tank into which exhaust heat air that has passed through the upstream tank is introduced. The upstream and downstream tanks are connected so that water can flow from the downstream tank to the upstream tank, and the first tank and the upstream tank may be connected so that water stored in the other tank does not flow into the other tank. With such a configuration, it is possible to appropriately separate the first tank, into which water containing impurities is stored, from the plurality of second tanks, while allowing water to flow between the plurality of second tanks, into which relatively clean water (hot water) is stored, for example by overflow, thereby achieving both reliable removal of impurities and ease of use.

[0009] [3] The heat recovery apparatus described in [1] or [2] above may further include wall sections provided in the first and second tanks, respectively, which cause a swirling flow in the exhaust heat air by colliding with it. With such a configuration, the water and exhaust heat air can be mixed more easily, and impurities can be removed in the first tank and hot water can be provided in the second tank more effectively. [Effects of the Invention]

[0010] According to this disclosure, it is possible to provide a heat recovery device that prevents performance degradation and reduces operating costs. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram of the heat recovery system according to this embodiment. [Figure 2] Figure 2 is a diagram illustrating the function of the heat recovery device included in the heat recovery system shown in Figure 1. [Figure 3] Figure 3 shows the temperature changes in each region. [Figure 4] Figure 4(a) shows the airflow as viewed from above, and Figure 4(b) is a simulation of the airflow as viewed from above. [Figure 5] Figure 5(a) shows a side view of the air and water flow, and Figure 5(b) is a simulation diagram of the air flow viewed from the side. [Figure 6] Figure 6 is a table illustrating the flow of the control method. [Modes for carrying out the invention]

[0012] An embodiment will be described below with reference to the drawings. In this description, the same elements or elements having the same function will be denoted by the same reference numeral, and redundant descriptions will be omitted.

[0013] Figure 1 is a schematic diagram of the heat recovery system 1 according to this embodiment. The heat recovery system 1 comprises a factory furnace 100 (e.g., a drying furnace) that discharges waste hot air, and a heat recovery device 10 that recovers heat from the waste hot air. The waste hot air from the furnace 100 is sent towards the heat recovery device 10 by, for example, a blower 50. The waste hot air is exhaust gas and contains many impurities such as dust and tar components. The heat recovery device 10 of the heat recovery system 1 is designed for air containing many such impurities (especially heavily soiled air), and a dirt recovery tank 11 (details described later) is installed at the upstream end to actively recover dirt.

[0014] Figure 2 is a diagram illustrating the function of the heat recovery device 10 included in the heat recovery system 1 shown in Figure 1. As shown in Figure 2, the heat recovery device 10 includes a dirt collection tank 11 (first tank), a first hot water supply tank 12 (second tank, upstream tank), a second hot water supply tank 13 (second tank, downstream tank), a third hot water supply tank 14 (second tank), a water pump 21a (first supply unit), a spray nozzle 21b (first supply unit), a water pump 22a (second supply unit), a spray nozzle 22b (second supply unit), a water pump 23a (second supply unit), a spray nozzle 23b (second supply unit), a water pump 24a (second supply unit), a spray nozzle 24b (second supply unit), overflow pipes 31, 32, a water inlet 41, a hot water outlet 42, and a drain valve 43 (see Figure 1). Thus, the heat recovery device 10 has a multi-stage (four-stage in this case) configuration, with the uppermost fouling recovery tank 11 being for removing impurities from the exhaust heat air, and the other tanks (first to third hot water supply tanks 12, 13, 14) being for recovering heat from clean exhaust heat air and supplying hot water. The exhaust heat air flows in the order of fouling recovery tank 11, first hot water supply tank 12, second hot water supply tank 13, and third hot water supply tank 14. In this case, the airflow rate of the exhaust heat air is, for example, 2 m³ 3 A temperature of around / mir is acceptable. Furthermore, one or more hot water supply tanks are sufficient for the second tank to function as a hot water supply tank.

[0015] The dirt collection tank 11 is provided to be able to store water and is a water tank into which the exhaust heat air from the furnace 100, which is a factory facility, is introduced. The exhaust heat air introduced into the dirt collection tank 11 may be, for example, at a temperature of about 80°C, a humidity of about 4%, and a specific enthalpy of about 111.9 KJ / Kg. The exhaust heat air may be, for example, at a temperature of ±5 to 10% from 100°C. The dirt collection tank 11 may store, for example, about 176 L of water.

[0016] The water pump 21a is a pump that pumps up the water stored in the dirt collection tank 11 and supplies it to the spray nozzle 21b. The flow rate of the water pump 21a may be, for example, about 11 L / min. The spray nozzle 21b is provided at the upper end of the dirt collection tank 11 and sprays (supplies) the water supplied to the water pump 21a onto the exhaust heat air passing through the dirt collection tank 11 and mixes it with the impurities in the exhaust heat air. The particle size of the spray nozzle 21b may be, for example, about 420 μm. Then, the water from which the impurities have been removed from the exhaust heat air is stored again in the dirt collection tank 11. As a result, the water stored in the dirt collection tank 11 becomes a dirty state containing impurities. Also, since it touches the exhaust heat air on the most upstream side, the water stored in the dirt collection tank 11 is warm water at a high temperature (for example, about 33°C). The warm water may be warm water at about 30°C to 50°C.

[0017] The first warm water supply tank 12 is provided to be able to store water and is a water tank into which the exhaust heat air that has passed through the dirt collection tank 11 is introduced. The exhaust heat air introduced into the first warm water supply tank 12 is air from which impurities have been removed in the dirt collection tank 11. The first warm water supply tank 12 may store, for example, about 263 L of water.

[0018] The water pump 22a is a pump that pumps up the water stored in the first hot water supply tank 12 and supplies it to the spray nozzle 22b. The spray nozzle 22b is provided at the upper end of the first hot water supply tank 12, and sprays (supplies) the water supplied to the water pump 22a onto the exhaust heat air passing through the first hot water supply tank 12. Then, the water whose temperature has risen by coming into contact with the exhaust heat air is stored again in the first hot water supply tank 12. As a result, the water stored in the first hot water supply tank 12 becomes hot water with a high temperature (for example, about 33°C).

[0019] The second hot water supply tank 13 is provided so that water can be stored, and is a water tank into which the exhaust heat air that has passed through the first hot water supply tank 12 is introduced. The exhaust heat air introduced into the second hot water supply tank 13 is air that has been purified of impurities in the dirt collection tank 11 and has passed through the first hot water supply tank 12. The second hot water supply tank 13 may store, for example, about 351 L of water.

[0020] The water pump 23a is a pump that pumps up the water stored in the second hot water supply tank 13 and supplies it to the spray nozzle 23b. The spray nozzle 23b is provided at the upper end of the second hot water supply tank 13, and sprays (supplies) the water supplied to the water pump 23a onto the exhaust heat air passing through the second hot water supply tank 13. Then, the water whose temperature has risen by coming into contact with the exhaust heat air is stored again in the second hot water supply tank 13. As a result, the water stored in the second hot water supply tank 13 becomes hot water with a high temperature (for example, about 28°C).

[0021] The third hot water supply tank 14 is provided so that water can be stored, and is a water tank into which the exhaust heat air that has passed through the second hot water supply tank 13 is introduced. The exhaust heat air introduced into the third hot water supply tank 14 is air that has been purified of impurities in the dirt collection tank 11 and has passed through the first hot water supply tank 12 and the second hot water supply tank 13. The third hot water supply tank 14 may store, for example, about 438 L of water. Cold water at about 12°C is introduced into the third hot water supply tank 14 from the water inlet 41.

[0022] The water pump 24a is a pump that draws up water stored in the third hot water supply tank 14 and supplies it to the spray nozzle 24b. The spray nozzle 24b is installed at the upper end of the third hot water supply tank 14 and sprays (supplies) the water supplied to the water pump 24a to the exhaust heat air passing through the third hot water supply tank 14. The water, whose temperature has risen upon contact with the exhaust heat air, is then stored again in the third hot water supply tank 14. As a result, the water stored in the fourth hot water supply tank 14 becomes hot water with a high temperature (for example, around 22°C).

[0023] The first hot water supply tank 12, the second hot water supply tank 13, and the third hot water supply tank 14 are connected so that hot water can flow from the downstream tank to the upstream tank. Specifically, the first hot water supply tank 12 and the second hot water supply tank 13 are connected by an overflow pipe 31. Overflowing hot water can flow from the second hot water supply tank 13 to the first hot water supply tank 12. Also, the second hot water supply tank 13 and the third hot water supply tank 14 are connected by an overflow pipe 32. Overflowing hot water can flow from the third hot water supply tank 14 to the second hot water supply tank 13. Note that hot water does not flow backward (from the upstream side to the downstream side). Furthermore, although the waste recovery tank 11 and the first hot water supply tank 12 are adjacent to each other and exhaust air can flow through them, they are connected so that water stored in the other tank does not flow into the other tank.

[0024] The hot water outlet 42 is provided, for example, in the first hot water supply tank 12, and is configured to extract hot water from the first hot water supply tank 12 and utilize its heat. The drain valve 43 is provided in the waste collection tank 11 and is a valve for appropriately discharging wastewater containing impurities.

[0025] Figure 3 shows the temperature changes in each region. In the example shown in Figure 3, the horizontal axis represents time (h) and the vertical axis represents temperature (°C). As shown in Figure 3, there are temperature changes immediately after the start, but as time passes, the temperature in all regions stabilizes, with the dirt collection tank 11 and the first hot water supply tank 12 having the highest temperatures, followed by the air temperature at the second hot water supply tank 13 and the hot water outlet 42, the chilled water temperature at the third hot water supply tank 14 and the water inlet 41, and then the outside air. In the example shown in Figure 3, there is a temperature difference of about 20°C between the dirt collection tank 11 and the first hot water supply tank 12 and the chilled water temperature at the water inlet 41.

[0026] Here, the heat recovery device 10 may further include wall sections provided in the dirt recovery tank 11 and the first to third hot water supply tanks 12, 13, and 14, which cause a swirling flow in the exhaust heat air by colliding with it. Figure 4(a) is a diagram showing the airflow viewed from above, and Figure 4(b) is a simulation diagram of the airflow viewed from above. Figure 5(a) is a diagram showing the air and water flow viewed from the side, and Figure 5(b) is a simulation diagram of the airflow viewed from the side. In Figures 4 and 5, the wall section 70 provided in the dirt recovery tank 11 is described, but as mentioned above, similar wall sections may also be provided in the first to third hot water supply tanks 12, 13, and 14.

[0027] As shown in Figures 4(a) and 4(b), the wall portion 70 is formed in an L-shape in top view by a first wall portion 71 extending in a direction intersecting the inflow direction of the exhaust heat air flowing into the dirt collection tank 11, and a second wall portion 72 extending from the end of the first wall portion 71 in a direction intersecting the first wall portion 71. By providing such a wall portion 70, a swirling flow is imparted to the exhaust heat air introduced along the L-shape of the wall portion 70. As shown in Figures 5(a) and 5(b), the imparting of a swirling flow to the exhaust heat air makes it easier for the water sprayed from the spray nozzle 21b and the swirling exhaust heat air to mix, allowing for more effective removal of impurities. Even when walls are provided in the first to third hot water supply tanks 12, 13, and 14, the sprayed water and the swirling exhaust heat air mix more easily, allowing for more efficient heat recovery.

[0028] In this case, if the exhaust air is relatively clean, the operation of water pump 21a can be stopped while the operation of water pump 22a, etc., is continued, thereby reducing electricity consumption while obtaining hot water.

[0029] Figure 6 is a table illustrating the control method flow when the control described above is performed. In Figure 6, "Tank 1" refers to the dirt recovery tank 11, "Tank 2" refers to the first hot water supply tank 12, "Tank 3" refers to the second hot water supply tank 13, and "Tank 4" refers to the third hot water supply tank 14. Now, in the initial state, step S1, the factory furnace 100 is stopped.

[0030] From this state, the furnace 100 is started to operate (step S2). Immediately after the furnace 100 is started to operate, the exhaust heat air is clean. For example, when the temperature of the fouling recovery tank 11 reaches the set temperature (step S3), the operation of the water pump 21a related to fouling recovery is stopped because the exhaust heat air is clean, thereby reducing the amount of electricity used (step S4). Subsequently, for example, when the first hot water supply tank 12 reaches the set temperature, the use of hot water in the first hot water supply tank 12 is started (step S5). Then, once the heating is complete, the preparation for the process is complete (step S6).

[0031] When production starts at the factory, for example, contaminated exhaust air flows into the fouling recovery tank 11. As a result, the water pump 21a starts operating and inverter control is performed (step S7). Subsequently, the inverter control of the water pump 21a is performed according to the degree of contamination of the exhaust heat air flowing into the fouling recovery tank 11 (steps S8 to S24). When the operation of the furnace 100 ends, the use of hot water is stopped (step S26).

[0032] Finally, the operation and effects of the heat recovery device 10 according to this embodiment will be described.

[0033] The heat recovery device 10 includes a dirt recovery tank 11 that is capable of storing water and into which exhaust heat air from the equipment is introduced; a first supply unit that pumps up the water stored in the dirt recovery tank 11 and supplies it to the exhaust heat air passing through the dirt recovery tank 11; one or more hot water supply tanks 12, 13, 14 that are capable of storing water and into which the exhaust heat air that has passed through the dirt recovery tank 11 is introduced; and a second supply unit that is provided individually in correspondence to each of the one or more hot water supply tanks 12, 13, 14 and pumps up the water stored in the hot water supply tanks 12, 13, 14 and supplies it to the exhaust heat air passing through the second tank.

[0034] With this configuration, in the waste recovery tank 11, which is the upstream tank in the waste heat air flow path, water is supplied to the waste heat air, and impurities in the waste heat air are removed (water containing impurities is stored in the waste recovery tank 11). Then, in the hot water supply tanks 12, 13, and 14, water is supplied to the waste heat air from which impurities have been removed to some extent, making it possible to recover heat with clean air and provide hot water. Thus, with the heat recovery device 10 according to this embodiment, heat can be recovered (hot water can be provided) without causing problems such as blockage of the heat exchanger due to impurities, which was a problem in the past. In other words, with the configuration according to this embodiment, it is possible to provide a heat recovery device 10 that prevents performance degradation and reduces operating costs.

[0035] With this configuration, total heat exchange can always be performed regardless of the enthalpy of the target gas, allowing for the removal of harmful substances and purification of factory waste heat air. Traditionally, low-temperature waste heat from furnaces, etc., at around 100°C to 150°C, had few uses. There was a need to separate contaminants from dirty waste heat air and recover the heat. Such heat can be efficiently recovered by using a multi-stage tank system.

[0036] The heat recovery device 10 described above includes a plurality of hot water supply tanks 12, 13, and 14. The plurality of hot water supply tanks 12, 13, and 14 include a first hot water supply tank 12 adjacent to the dirt recovery tank 11 into which exhaust heat air that has passed through the dirt recovery tank 11 is introduced, and a second hot water supply tank 13 adjacent to the first hot water supply tank 12 into which exhaust heat air that has passed through the first hot water supply tank 12 is introduced. The first hot water supply tank 12 and the second hot water supply tank 13 are connected so that water can flow from the second hot water supply tank 13 to the first hot water supply tank 12. The dirt recovery tank 11 and the first hot water supply tank 12 may be connected so that water stored in the other does not flow into the other. With this configuration, it is possible to appropriately separate the first tank, where water containing impurities is stored, from the multiple second tanks, so that water does not flow back and forth between them, while allowing water to flow back and forth between the multiple second tanks, where relatively clean water (hot water) is stored, for example by overflow. This makes it possible to achieve both reliable removal of impurities and ease of use.

[0037] The heat recovery device 10 described above may further include wall sections (for example, wall section 70) provided in the first and second tanks, respectively, which cause a swirling flow in the exhaust heat air by colliding with it. With such a configuration, the water and exhaust heat air can be mixed more easily, and impurities can be removed in the first tank and hot water can be provided in the second tank more effectively. [Explanation of Symbols]

[0038] 10...Heat recovery unit, 11...Dirt recovery tank (first tank), 12-14...Hot water supply tank (second tank), 21a...Water pump (first supply unit), 21b...Spray nozzle (first supply unit), 22a, 23a, 24a...Water pump (second supply unit), 22b, 23b, 24b...Spray nozzle (second supply unit), 70...Wall section.

Claims

1. A first tank is provided that is capable of storing water and into which exhaust heat air from the equipment is introduced, A first supply unit that pumps up the water stored in the first tank and supplies it to the exhaust heat air passing through the first tank, One or more second tanks are provided to store water, and into which the exhaust heat air that has passed through the first tank is introduced. A heat recovery apparatus comprising: a second supply unit provided individually in correspondence to each of the one or more second tanks, which pumps up the water stored in the second tanks and supplies it to the exhaust heat air passing through the second tanks.

2. It is equipped with multiple of the aforementioned second tanks, The plurality of second tanks are configured to include an upstream tank adjacent to the first tank into which the exhaust heat air that has passed through the first tank is introduced, and a downstream tank adjacent to the upstream tank into which the exhaust heat air that has passed through the upstream tank is introduced. The upstream tank and the downstream tank are connected such that water can flow from the downstream tank into the upstream tank. The heat recovery apparatus according to claim 1, wherein the first tank and the upstream tank are connected so that water stored in the other tank does not flow into each other.

3. The heat recovery apparatus according to claim 1 or 2, further comprising a wall portion provided in the first tank and the second tank, which causes a swirling flow in the exhaust heat air by colliding with it.

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