Heat exchange apparatus and heat exchange method

Abstract

This suppresses dust buildup on heat exchange piping. [Solution] The heat exchanger 100 comprises an exhaust gas passage 110 through which exhaust gas containing dust gas generated by the vaporization of dust flows, a heat exchange pipe 120 provided within the exhaust gas passage 110, a dilution gas supply device 140 that supplies dilution gas upstream of the heat exchange pipe 120 in the exhaust gas passage 110, and a control device 180 that controls the amount of dilution gas supplied by the dilution gas supply device 140 based on the composition of the dust gas.

Description

Technical Field

[0001] The present disclosure relates to a heat exchange apparatus and a heat exchange method.

Background Art

[0002] Exhaust gas discharged from an electric furnace for manufacturing steel has a high temperature of about 1000°C. For this reason, in facilities equipped with an electric furnace, techniques for recovering heat from high-temperature exhaust gas are utilized.

[0003] For example, Patent Document 1 discloses a technique in which a heat exchanger through which water flows is installed outside an exhaust gas guide passage through which exhaust gas discharged from an electric furnace flows, and in this heat exchanger, heat is indirectly exchanged between the exhaust gas and the water via the wall of the exhaust gas guide passage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The outside of the indirect heat exchanger as described in the above Patent Document 1 is exposed to the atmosphere. For this reason, the heat loss of the indirect heat exchanger is larger than that of a direct heat exchanger in which heat exchange pipes are provided in the exhaust gas flow path through which exhaust gas flows. Therefore, as a technique for efficiently recovering heat from high-temperature exhaust gas, it is conceivable to install the above-described direct heat exchanger.

[0006] However, since the exhaust gas discharged from an electric furnace or the like contains dust gas generated by vaporization of dust, if the heat exchange pipes of the direct heat exchanger are provided directly in the exhaust gas flow path, dust will adhere to the outer walls of the heat exchange pipes, which causes a problem that the heat recovery efficiency decreases.

[0007] In view of these issues, this disclosure aims to provide a heat exchange apparatus and a heat exchange method that can suppress the adhesion of dust to heat exchange piping. [Means for solving the problem]

[0008] To solve the above problems, a heat exchanger according to one aspect of the present disclosure comprises an exhaust gas flow path through which exhaust gas containing dust gas generated by the vaporization of dust flows, heat exchange piping provided in the exhaust gas flow path, a dilution gas supply device that supplies dilution gas to the upstream side of the heat exchange piping in the exhaust gas flow path, and a control device that controls the amount of dilution gas supplied by the dilution gas supply device based on the composition of the dust gas.

[0009] The dust may contain compounds of either zinc or lead, or both.

[0010] The exhaust gas passage may be connected to an electric furnace, and the exhaust gas may be discharged from the electric furnace.

[0011] The heat exchange device described above may further include a baffle plate provided on the upstream side of the heat exchange piping in the exhaust gas flow path.

[0012] The heat exchange apparatus described above may further include a cooling device for cooling the baffle plates, and the cooling temperature of the baffle plates cooled by the cooling device may be set according to the target temperature of the exhaust gas sent to the heat exchange piping.

[0013] The control device may control the supply amount of diluent gas based on the composition of the dust gas and the vapor pressure of the dust.

[0014] To solve the above problems, a heat exchange method according to one aspect of the present disclosure includes supplying a diluent gas to the upstream side of a heat exchange pipe provided in an exhaust gas flow path through which exhaust gas containing dust gas generated by the vaporization of dust flows, and controlling the amount of diluent gas supplied based on the composition of the dust gas. [Effects of the Invention]

[0015] According to this disclosure, it is possible to suppress the adhesion of dust to heat exchange piping. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic diagram of a heat exchanger according to an embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic diagram showing the vicinity of the heat exchange piping according to the same embodiment. [Figure 3] Figure 3 is a graph showing an example of a dust vapor pressure curve. [Figure 4] Figure 4 is a flowchart showing the processing flow of the heat exchange method according to the same embodiment. [Modes for carrying out the invention]

[0017] Embodiments of this disclosure will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for the purpose of facilitating understanding and do not limit this disclosure unless otherwise specified. In this specification and in the drawings, elements having substantially the same function or configuration are denoted by the same reference numerals to avoid redundant explanations. Elements not directly related to this disclosure are omitted from the illustrations.

[0018] [1. Overview of Heat Exchanger] First, an overview of the heat exchanger 100 according to the embodiment of this disclosure will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram of the heat exchanger 100 according to this embodiment. In Figure 1, solid arrows indicate the flow of exhaust gas, heat transfer medium, and diluent gas. In Figure 1, dashed arrows indicate the flow of signals. Figure 2 is a schematic diagram showing the vicinity of the heat exchange piping 120 according to this embodiment. In Figure 2, solid arrows indicate the flow of heat transfer medium. In Figure 2, white arrows indicate the flow of diluent gas. In Figure 2, gray arrows indicate exhaust gas.

[0019] As shown in Figure 1, the heat exchange device 100 according to the present embodiment includes an exhaust gas flow path 110, heat exchange piping 120, a heat medium supply device 130, a dilution gas supply device 140, a baffle plate 150, a cooling device 160, a concentration sensor 170, a temperature sensor 172, and a control device 180.

[0020] The exhaust gas flow path 110 is a flow path through which exhaust gas containing dust gas generated by vaporization of dust flows. In the present embodiment, the dust includes dust having a particle size of 100 μm or less and fumes having a particle size of 1 μm or less. That is, the dust gas includes a gas obtained by vaporizing dust having a particle size of 100 μm or less, and a gas obtained by vaporizing fumes having a particle size of 1 μm or less. The exhaust gas flow path 110 is connected to, for example, an electric furnace 102. The electric furnace 102 manufactures steel by melting, for example, iron scrap. Exhaust gas discharged from the electric furnace 102 flows through the exhaust gas flow path 110. The exhaust gas discharged from the electric furnace 102 includes, for example, dust gas generated by vaporization of dust derived from paint adhering to the iron scrap. The paint contains, for example, one or both of zinc chloride and lead chloride. Therefore, in the present embodiment, the dust gas contains one or both of zinc chloride and lead chloride.

[0021] In the present embodiment, the exhaust gas flow path 110 has a first flow path 112, a second flow path 114, and a third flow path 116. The first flow path 112 is connected to an opening 102a provided on the upper surface of the electric furnace 102. The first flow path 112 has, for example, a vertical flow path 112a and a horizontal flow path 112b. The vertical flow path 112a is connected to the opening 102a and extends in a substantially vertical direction. The horizontal flow path 112b is connected to the vertical flow path 112a and extends in a substantially horizontal direction.

[0022] The second channel 114 is connected to the first channel 112. The second channel 114 is, for example, in an inverted U shape. The second channel 114 has two straight channels 114a and 114b that extend substantially vertically and are arranged substantially horizontally, and a connecting channel 114c that connects the upper parts of the two straight channels 114a and 114b. The first channel 112 is connected to one of the straight channels 114a of the second channel 114.

[0023] The third channel 116 is connected to the second channel 114. The third channel 116 is connected, for example, to the other straight channel 114b of the second channel 114. The third channel 116 has a horizontal channel 116a and an inclined channel 116b. The horizontal channel 116a is connected to the straight channel 114b of the second channel 114 and extends horizontally. The inclined channel 116b is connected to the horizontal channel 116a and extends diagonally upward.

[0024] The heat exchange piping 120 is provided within the exhaust gas flow path 110. In this embodiment, the heat exchange piping 120 is provided, for example, within the inclined flow path 116b of the exhaust gas flow path 110. The heat exchange piping 120 is in direct contact with the exhaust gas flowing within the exhaust gas flow path 110. The heat exchange piping 120 is a flow path through which a heat transfer medium flows. The heat transfer medium is a fluid. The heat transfer medium is, for example, water or air. The heat transfer medium flows within the heat exchange piping 120.

[0025] The heat transfer medium supply device 130 supplies a heat transfer medium to the heat exchange piping 120. The heat transfer medium supplied to the heat exchange piping 120 by the heat transfer medium supply device 130 is heated by the exhaust gas flowing through the exhaust gas passage 110 and, for example, vaporizes. The heat transfer medium heated in the heat exchange piping 120 is supplied to a heat transfer medium utilization facility (not shown). The heat transfer medium utilization facility is, for example, a steam turbine. The heat transfer medium supply device 130 includes, for example, a pump 132. The suction side of the pump 132 is connected to a heat transfer medium supply source (not shown). The discharge side of the pump 132 is connected to the heat exchange piping 120.

[0026] The dilution gas supply device 140 supplies dilution gas to the upstream side of the heat exchange piping 120 in the exhaust gas flow path 110. For example, the dilution gas supply device 140 supplies dilution gas to the upstream side of the heat exchange piping 120 in the inclined flow path 116b. The concentration of dust gas in the dilution gas is lower than the concentration of dust gas in the exhaust gas. The dilution gas is, for example, a gas that does not contain dust gas. However, the dilution gas may contain dust gas as an unavoidable impurity. The dilution gas consists of one or more gases selected from the group consisting of, for example, air, water vapor, nitrogen gas, and combustion exhaust gas. The dilution gas is supplied to the exhaust gas in order to dilute the exhaust gas flowing in the exhaust gas flow path 110. By diluting the exhaust gas with the dilution gas, the concentration of dust gas in the exhaust gas can be reduced.

[0027] The temperature of the dilution gas is preferably close to the temperature of the exhaust gas flowing through the exhaust gas passage 110. If the temperature of the exhaust gas flowing through the exhaust gas passage 110 is, for example, 700°C or more and 800°C or less, the temperature of the dilution gas is, for example, 300°C or more and 800°C or less, preferably 500°C or more and 600°C or less. If the temperature of the dilution gas is below 300°C, the temperature of the exhaust gas sent to the heat exchange piping 120 will drop too low, reducing the heat exchange efficiency. On the other hand, if the temperature of the dilution gas exceeds 800°C, the energy consumption required to heat the dilution gas will increase. Therefore, by setting the temperature of the dilution gas to 300°C or more and 800°C or less, it is possible to suppress the temperature drop of the exhaust gas sent to the heat exchange piping 120 and reduce the energy consumption required to heat the dilution gas. Note that if the dilution gas is steam at 300°C or higher exhausted from a boiler, steam turbine, etc., or combustion exhaust gas at 300°C or higher exhausted from a furnace, it is not necessary to heat the dilution gas. However, if the temperature of the diluent gas is less than 300°C, the diluent gas may be heated by an electric heater using nichrome wire or the like, or by using the thermal energy obtained by heat exchange with the exhaust gas in the heat exchange piping 120.

[0028] The dilution gas supply device 140 includes, for example, a blower 142 and a supply pipe 144. The suction side of the blower 142 is connected to a dilution gas supply source (not shown). The discharge side of the blower 142 is connected to the upstream side of the heat exchange piping 120 in the exhaust gas flow path 110 through the supply pipe 144. In this embodiment, the supply pipe 144 is connected to the discharge side of the blower 142 and to an opening 110a (see Figure 2) formed in the inclined flow path 116b. Therefore, the dilution gas supplied by the blower 142 is supplied into the inclined flow path 116b through the opening 110a.

[0029] As shown in Figure 2, the opening 110a is formed upstream of the installation location of the heat exchange piping 120 in the inclined flow channel 116b. The opening 110a is, for example, slit-shaped. The opening 110a extends, for example, in a direction intersecting the exhaust gas flow direction. The opening 110a extends, for example, in a direction perpendicular to the exhaust gas flow direction. Therefore, the dilution gas supplied by the dilution gas supply device 140 is supplied in a band-like manner within the inclined flow channel 116b along a direction intersecting the exhaust gas flow direction. This allows the exhaust gas to be evenly diluted by the dilution gas. Therefore, the concentration of dust gas in the exhaust gas sent to the heat exchange piping 120 can be made uniform.

[0030] Returning to Figure 1, the baffle plate 150 is installed upstream of the heat exchange piping 120 in the exhaust gas flow path 110. The baffle plate 150 is installed, for example, in the straight flow path 114b of the second flow path 114 of the exhaust gas flow path 110. The baffle plate 150 is installed in the second flow path 114 such that most of the exhaust gas sent from the second flow path 114 to the third flow path 116 collides with the baffle plate 150. For example, the baffle plate 150 is installed in the second flow path 114 such that, when viewed from the straight flow path 114b to the horizontal flow path 116a, the baffle plate 150 covers more than 50% of the vertical cross-sectional area of ​​the horizontal flow path 116a. The exhaust gas that collides with the front side of the baffle plate 150 in the second flow path 114 wraps around to the back side of the baffle plate 150 and is sent to the horizontal flow path 116a.

[0031] The cooling device 160 cools the baffle plate 150. The cooling device 160, for example, water-cools the baffle plate 150. The cooling temperature of the baffle plate 150 cooled by the cooling device 160 is set, for example, according to the target temperature of the exhaust gas sent to the heat exchange piping 120.

[0032] The concentration sensor 170 detects the concentration of dust gas in the exhaust gas flowing through the exhaust gas passage 110. For example, the concentration sensor 170 detects the concentration of dust gas in the exhaust gas flowing through the horizontal passage 116a.

[0033] The temperature sensor 172 detects the temperature of the exhaust gas flowing through the exhaust gas passage 110. The temperature sensor 172 also detects the temperature of the exhaust gas flowing through the horizontal passage 116a, for example.

[0034] The control device 180 includes, for example, a processor 180a and a memory 180b. The processor 180a includes, for example, a central processing unit (CPU). The memory 180b includes, for example, a ROM in which programs are stored and RAM as a work area. The functions of the control device 180 are realized, for example, by the execution of a program stored in the memory 180b by the processor 180a.

[0035] The processor 180a controls each device within the heat exchanger 100. For example, the processor 180a can control the flow rate of the heat transfer medium supplied to the heat exchange piping 120 by controlling the pump 132. For example, the processor 180a can control the flow rate of the diluent gas supplied to the exhaust gas passage 110 by controlling the blower 142. For example, the processor 180a can control the temperature of the baffle plate 150 by controlling the cooling device 160. The processor 180a can also obtain detection results from the concentration sensor 170 and the temperature sensor 172.

[0036] In this embodiment, the processor 180a controls the amount of dilution gas supplied by the dilution gas supply device 140 based on the composition of the dust gas. The processor 180a may also control the amount of dilution gas supplied based on the composition of the dust gas and the vapor pressure of the dust. The composition of the dust gas refers to the components of the dust gas and the concentration of dust gas in the exhaust gas. Details of the control of the amount of dilution gas supplied by the processor 180a will be described later.

[0037] Furthermore, in this embodiment, the processor 180a controls the cooling device 160 to adjust the temperature of the baffle plate 150 so that the temperature of the exhaust gas sent to the heat exchange piping 120 reaches the target temperature. The target temperature is determined, for example, based on the target temperature of the heated heat transfer medium sent from the heat exchange piping 120 and the condensation temperature (liquefaction temperature) of the dust gas. The target temperature of the heated heat transfer medium is determined based on the required temperature in the heat transfer medium utilization equipment.

[0038] In this embodiment, memory 180b pre-stores component information indicating the components of the dust gas, and vapor pressure information indicating the vapor pressure curves of various components that can become dust. The component information and vapor pressure information are pre-stored in memory 180b by, for example, the operator of the heat exchanger 100. The operator of the heat exchanger 100 obtains the component information based, for example, on the type of iron scrap supplied to the electric furnace 102.

[0039] [2. Processing by the control device] Next, the processing by the control device according to this embodiment will be described with reference to Figure 3. Figure 3 is a graph showing an example of a dust vapor pressure curve. In Figure 3, the horizontal axis represents the temperature of the exhaust gas [°C]. In Figure 3, the left vertical axis represents the concentration of dust gas in the exhaust gas [ppm]. In Figure 3, the right vertical axis represents the ratio η of the amount of diluent gas [g] to the amount of dust gas [g]. η is expressed by the following formula (1). η = exhaust gas flow rate [m 3 / s] / Dust gas flow rate [g / s] = 1 / Concentration of dust gas in exhaust gas [g / m³] 3 ] …Formula (1)

[0040] For example, consider the case where the exhaust gas temperature is temperature T. In this case, if the concentration of dust gas in the exhaust gas is greater than concentration C1, some of the dust will be in a liquid state. On the other hand, if the concentration of dust gas in the exhaust gas is less than or equal to concentration C1, the dust will be in a gaseous state.

[0041] Here, if no diluent gas is supplied, i.e., η=0, then assume that the concentration of the dust gas is higher than concentration C1, i.e., concentration C2. In that case, if the exhaust gas temperature is temperature T, then some of the dust in the exhaust gas will be in a liquid state.

[0042] Therefore, the control device 180 reduces the partial pressure of dust gas by increasing the amount of diluent gas supplied to the exhaust gas passage 110. In other words, the control device 180 reduces the concentration of dust gas in the exhaust gas by increasing the amount of diluent gas supplied to the exhaust gas passage 110. For example, the control device 180 increases the amount of diluent gas supplied to the exhaust gas passage 110, reducing the concentration of dust gas in the exhaust gas to a concentration C1 or lower. As a result, the control device 180 can convert liquid dust into gaseous dust gas. Therefore, the control device 180 can suppress the adhesion of liquid dust to the heat exchange piping 120.

[0043] Specifically, the processor 180a of the control device 180 refers to the component information stored in the memory 180b to identify the components of the dust gas. The processor 180a also obtains the exhaust gas temperature from the temperature sensor 172.

[0044] Then, the processor 180a refers to the vapor pressure information stored in memory 180b and calculates the maximum concentration C1, which is the maximum concentration at which the dust becomes gaseous, based on the vapor pressure curve of the identified component and the temperature of the acquired exhaust gas.

[0045] The processor 180a obtains the dust concentration in the exhaust gas from the concentration sensor 170 and calculates η=D, which is the value at which the dust concentration in the exhaust gas becomes concentration C1. For example, D is greater than 1.0 and less than or equal to 1.2. Then, the processor 180a calculates the flow rate (supply amount) of the diluent gas such that η=D or greater and the heat exchange efficiency of the heat exchange piping 120 does not decrease. Specifically, the processor 180a identifies the expected dust compounds (components) using, for example, thermodynamic equilibrium calculations and calculates the amount of each state (gas, liquid, solid) of the compounds. Then, based on the dust compounds and the amounts of each state of the compounds, the processor 180a calculates the flow rate of the diluent gas such that η=D or greater and the heat exchange efficiency of the heat exchange piping 120 does not decrease. For example, processor 180a uses thermodynamic equilibrium calculation software to calculate the flow rate of the diluent gas such that η = D or greater, and the heat exchange efficiency of the heat exchange piping 120 does not decrease. For example, "FactSage" can be used as the thermodynamic equilibrium calculation software.

[0046] The processor 180a then controls the dilution gas supply device 140 so that the dilution gas is supplied at the calculated flow rate of the dilution gas.

[0047] [3. Heat exchange method] Next, the heat exchange method according to this embodiment will be described with reference to Figure 4. Figure 4 is a flowchart showing the processing flow of the heat exchange method according to this embodiment. The processing flow shown in Figure 4 is repeated at a predetermined time interval.

[0048] In step S110, the processor 180a refers to the component information stored in memory 180b and identifies the components of the dust gas.

[0049] In step S112, following step S110, the processor 180a obtains the exhaust gas temperature from the temperature sensor 172.

[0050] In step S114, following step S112, the processor 180a refers to the vapor pressure information stored in memory 180b and calculates the concentration C1, which is the maximum concentration at which the dust becomes gaseous, based on the vapor pressure curve of the component identified in step S110 and the exhaust gas temperature obtained in step S112.

[0051] Following step S114, in step S116, the processor 180a obtains from the concentration sensor 170 the concentration of the component identified in step S110 contained in the exhaust gas, i.e., the concentration of dust gas.

[0052] In step S118, following step S116, the processor 180a determines whether the concentration of the dust gas obtained in step S116 is less than or equal to concentration C1. If it is determined that the concentration of the dust gas is less than or equal to concentration C1 (YES in step S118), the processor 180a proceeds to step S120. On the other hand, if it is determined that the concentration of the dust gas is not less than or equal to concentration C1, that is, that the concentration of the dust gas is higher than concentration C1 (NO in step S118), the processor 180a proceeds to step S122.

[0053] In step S120, the processor 180a stops the operation of the dilution gas supply device 140 and terminates the processing flow shown in Figure 4.

[0054] In step S122, the processor 180a calculates η=D such that the concentration of dust gas in the exhaust gas obtained in step S116 is concentration C1. Then, the processor 180a calculates the flow rate (supply amount) of diluent gas such that η=D or greater and the heat exchange efficiency of the heat exchange piping 120 does not decrease.

[0055] In step S124, following step S122, the processor 180a controls the dilution gas supply device 140 so that the dilution gas is supplied at the flow rate of the dilution gas calculated in step S122, thereby ending the processing flow shown in Figure 4.

[0056] [4. Summary] The heat exchange apparatus 100 and heat exchange method according to this embodiment have been described above.

[0057] The heat exchanger 100 according to this embodiment includes an exhaust gas flow path 110 through which exhaust gas containing dust gas generated by the vaporization of dust flows, a heat exchange piping 120 provided within the exhaust gas flow path 110, a dilution gas supply device 140 that supplies dilution gas upstream of the heat exchange piping 120 in the exhaust gas flow path 110, and a control device 180 that controls the amount of dilution gas supplied by the dilution gas supply device 140 based on the composition of the dust gas.

[0058] As described above, the heat exchanger 100 according to this embodiment can reduce the partial pressure of dust gas in the exhaust gas by supplying dilution gas to the exhaust gas flow path 110. This allows the heat exchanger 100 according to this embodiment to change at least a portion of the dust from a liquid state to a gaseous state. Therefore, the heat exchanger 100 according to this embodiment can suppress the adhesion of liquid dust to the heat exchange piping 120. As a result, the heat exchanger 100 according to this embodiment can suppress the decrease in the heat exchange efficiency of the heat exchange piping 120 due to dust. Therefore, the heat exchanger 100 according to this embodiment can improve the heat recovery efficiency of the heat exchange piping 120.

[0059] The dust may contain compounds of either zinc or lead, or both.

[0060] Compounds of zinc and lead, or both, with chlorine, namely zinc chloride and lead chloride, are low-melting-point compounds and therefore condense easily. For this reason, if the dust gas contains zinc and lead, or both, with chlorine, zinc chloride or lead chloride tends to condense and adhere to the heat exchange piping 120. The heat exchange apparatus 100 according to this embodiment is equipped with a dilution gas supply device 140, so even if the dust contains compounds of zinc and lead, or both, the adhesion of dust to the heat exchange piping 120 can be effectively suppressed.

[0061] The exhaust gas passage 110 is connected to the electric furnace 102, and the exhaust gas may be discharged from the electric furnace 102.

[0062] As a result, the heat exchanger 100 according to this embodiment can efficiently recover the heat contained in the high-temperature exhaust gas discharged from the electric furnace 102.

[0063] The heat exchanger 100 according to this embodiment may further include a baffle plate 150 provided on the upstream side of the heat exchange piping 120 in the exhaust gas flow path 110.

[0064] The baffle plate 150 according to this embodiment can recover dust gas from the exhaust gas. As a result, the heat exchanger 100 according to this embodiment can reduce the concentration of dust gas in the exhaust gas sent to the heat exchange piping 120. Therefore, the heat exchanger 100 according to this embodiment can further suppress the adhesion of dust to the heat exchange piping 120.

[0065] Furthermore, by including the baffle plate 150, the heat exchanger 100 according to this embodiment can reduce the concentration of dust gas in the exhaust gas sent to the heat exchange piping 120, thereby reducing the amount of diluent gas supplied. As a result, the heat exchanger 100 according to this embodiment can improve the heat exchange efficiency in the heat exchange piping 120.

[0066] The heat exchanger 100 according to this embodiment further includes a cooling device 160 for cooling the baffle plate 150, and the cooling temperature of the baffle plate 150 cooled by the cooling device 160 may be set according to the target temperature of the exhaust gas sent to the heat exchange piping 120.

[0067] As a result, in this embodiment, the heat exchanger 100 can condense dust gas on the baffle plate 150 by cooling the baffle plate 150 with the cooling device 160. This allows the heat exchanger 100 to reduce the concentration of dust gas in the exhaust gas sent to the heat exchange piping 120. Therefore, the heat exchanger 100 can effectively suppress the adhesion of dust to the heat exchange piping 120.

[0068] The control device 180 may control the supply amount of diluent gas based on the composition of the dust gas and the vapor pressure of the dust.

[0069] As a result, the heat exchanger 100 according to this embodiment can further suppress the adhesion of dust to the heat exchange piping 120.

[0070] The heat exchange method according to this embodiment includes supplying a diluent gas to the upstream side of a heat exchange pipe 120 provided within an exhaust gas flow path 110 through which exhaust gas containing dust gas generated by the vaporization of dust flows, and controlling the amount of diluent gas supplied based on the composition of the dust gas.

[0071] The heat exchange method according to this embodiment can achieve the same effects as the heat exchange device 100 described above.

[0072] While embodiments have been described above with reference to the attached drawings, it goes without saying that this disclosure is not limited to the embodiments described above. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of this disclosure.

[0073] For example, the configuration of the heat exchanger 100 was described above with reference to Figure 1. However, some components of the heat exchanger 100 may be omitted, and components may be added.

[0074] The above describes an example in which the control device 180 controls the supply amount of diluent gas based on the composition of the dust gas and the vapor pressure of the dust. However, the control device 180 may also control the supply amount of diluent gas based on the composition of the dust gas.

[0075] The above describes an example in which the control device 180 controls the supply amount of diluent gas based on the temperature of the exhaust gas. However, the control device 180 may also control the supply amount of diluent gas based on the composition of the dust gas. For example, the control device 180 may control the supply amount of diluent gas so that the concentration of the dust gas is below a predetermined value.

[0076] The above describes an example where, if the concentration of dust gas in the exhaust gas is greater than concentration C1, some of the dust becomes liquid, and if the concentration is C1 or less, the dust becomes gaseous. However, if the concentration of dust gas in the exhaust gas is greater than concentration C1, some of the dust may become solid, and if the concentration is C1 or less, the dust may become gaseous. In this case as well, the control device 180 increases the amount of diluent gas supplied to the exhaust gas flow path 110, reducing the concentration of dust gas in the exhaust gas to C1 or less. As a result, the control device 180 can convert solid dust into gaseous dust gas. Therefore, the control device 180 can suppress the adhesion of solid dust to the heat exchange piping 120.

[0077] The above describes an example in which the heat exchanger 100 is further equipped with a cooling device 160. However, the heat exchanger 100 does not necessarily have to be equipped with a cooling device 160.

[0078] The above describes an example in which the heat exchanger 100 is further equipped with baffle plates 150. However, the heat exchanger 100 does not necessarily have to be equipped with baffle plates 150.

[0079] The above describes an example in which the exhaust gas flow path 110 is connected to the electric furnace 102, and the exhaust gas is discharged from the electric furnace 102. However, the exhaust gas source does not have to be the electric furnace 102, as long as it is a device that can supply exhaust gas containing dust gas generated by the vaporization of dust to the exhaust gas flow path 110. For example, the exhaust gas source may be a waste incinerator or a reaction unit in a chemical plant.

[0080] The above describes an example in which the dust gas contains compounds of either zinc or lead, or both. However, the dust may also contain compounds of one or more metals selected from the group consisting of mercury, cadmium, and tin, in addition to zinc and lead. Furthermore, the metal compounds may be, for example, metal salts, metal halides, or metal chlorides.

[0081] The above describes an example in which the dilution gas supply device 140 supplies dilution gas to the upstream side of the heat exchange piping 120 in the exhaust gas flow path 110. However, the dilution gas supply device 140 may also supply dilution gas to the heat exchange piping 120 in the exhaust gas flow path 110, in addition to supplying it to the upstream side. This allows the dilution gas supply device 140 to remove dust adhering to the heat exchange piping 120 by blowing it away with the dilution gas.

[0082] The above describes an example in which one opening 110a is formed in the exhaust gas flow path 110. However, multiple openings 110a may be formed in the exhaust gas flow path 110.

[0083] The above describes an example in which memory 180b pre-stores component information indicating the composition of the dust gas. However, memory 180b does not need to pre-store component information. For example, a sensor for detecting the composition of the dust gas may be provided in the exhaust gas flow path 110. This sensor may be provided, for example, between the baffle plate 150 and the heat exchange piping 120, for example, in the horizontal flow path 116a.

[0084] The above describes an example in which the heat exchange piping 120 is provided in the inclined flow path 116b. However, the heat exchange piping 120 may also be provided in other flow paths within the exhaust gas flow path 110. In addition, the heat exchange piping 120 may be provided in a flow path through which exhaust gas at a temperature where the fluctuation range of the vapor pressure of the dust gas is less than or equal to a predetermined value flows.

[0085] Furthermore, the heat exchanger 100 may have a hopper for collecting dust adhering to the heat exchange piping 120. This hopper may be provided below the heat exchange piping 120 in the exhaust gas flow path 110.

[0086] Furthermore, the heat exchanger 100 may have a hopper for collecting dust adhering to the baffle plate 150. This hopper may be provided below the baffle plate 150 in the exhaust gas flow path 110.

[0087] This disclosure enables the efficient recovery of heat from high-temperature exhaust gases, leading to the effective utilization of thermal energy from exhaust gases. Therefore, it can contribute, for example, to Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, sustainable and modern energy." [Explanation of Symbols]

[0088] 100 Heat exchange equipment 102 Electric Furnace 110 Exhaust gas flow path 120 Heat exchange piping 140 Dilution gas supply device 150 Obstacle board 160 Cooling device 180 Control device

Claims

1. An exhaust gas passage through which exhaust gas containing dust gas, which is produced when dust vaporizes, A heat exchange pipe provided within the exhaust gas flow path, A dilution gas supply device is provided on the upstream side of the heat exchange piping in the exhaust gas flow path, which supplies dilution gas. A control device that controls the amount of dilution gas supplied by the dilution gas supply device based on the composition of the dust gas, A heat exchanger equipped with the following features.

2. The heat exchanger according to claim 1, wherein the dust contains a compound of one or both of zinc and lead.

3. The exhaust gas passage is connected to an electric furnace, The heat exchange apparatus according to claim 1 or 2, wherein the exhaust gas is discharged from the electric furnace.

4. The heat exchange apparatus according to claim 1 or 2, further comprising a baffle plate provided on the upstream side of the heat exchange piping in the exhaust gas flow path.

5. The system further includes a cooling device for cooling the aforementioned baffle plate, The heat exchange apparatus according to claim 4, wherein the cooling temperature of the baffle plate cooled by the cooling device is set according to the target temperature of the exhaust gas sent to the heat exchange piping.

6. The heat exchange apparatus according to claim 1 or 2, wherein the control device controls the amount of the diluent gas supplied based on the composition of the dust gas and the vapor pressure of the dust.

7. In an exhaust gas flow path through which exhaust gas containing dust gas generated by the vaporization of dust flows, a diluent gas is supplied to the upstream side of a heat exchange pipe installed within the said exhaust gas flow path. Based on the composition of the dust gas, the amount of the diluent gas supplied is controlled. A heat exchange method, including

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