KR102483427B1 - Complex waste heat recovery device - Google Patents

Abstract

The present invention relates to a complex waste heat recovery device, and more particularly, to a water supply tank; a first heat exchange unit for circulating and supplying wastewater, and circulating and supplying heated water generated through heat exchange between the water supplied from the water supply tank and waste water heat to the water supply tank; a second heat exchange unit supplying exhaust gas discharged through combustion of the boiler, and circulating and supplying heated water generated through heat exchange between the feed water supplied from the feed water tank and the exhaust heat of the exhaust gas to the feed water tank; and a control valve disposed on a water supply circulation line between the water supply tank and the first heat exchange unit or between the water supply tank and the second heat exchange unit, wherein the control valve is configured to include the first heat exchange unit and the first heat exchange unit. 2 It is characterized in that the water supply of the water supply tank is controlled so that the selective operation or sequential operation of the heat exchange unit is possible.
That is, the present invention maximizes energy efficiency by simultaneously using wastewater and waste heat to heat the temperature of feed water to a certain level or higher, and integrates the existing waste water recovery device, waste heat recovery device, and feed water tank into one system to recover waste water and waste heat. By doing so, a high-efficiency waste heat recovery device is provided, and through this, a complex waste heat recovery device that can save the installation space of the device and reduce the investment cost of facilities is proposed.

Description

Complex waste heat recovery device {Complex waste heat recovery device}

The present invention maximizes energy efficiency by simultaneously using wastewater and waste heat to heat the temperature of feed water to a certain level or higher, and systematizes by integrating an existing waste water recovery device, waste heat recovery device, and feed water tank into one to recover waste water and waste heat. Provides a high-efficiency waste heat recovery device, and relates to a complex waste heat recovery device capable of reducing the installation space of the device and the investment cost of facilities through this.

As is well known, a waste heat recovery system that raises the temperature of raw water supplied from a water supply tank using waste heat once used in large-scale facilities such as public baths, saunas, hotels, or industrial facilities is widely used.

A conventional waste heat recovery system includes a waste heat recovery device that uses exhaust heat exhausted from a boiler as a heat source to increase the temperature of raw water supplied from a water supply tank or lower the temperature of exhaust gas by preheating the feed water.

The above-mentioned conventional waste heat recovery device is installed in the flue of the boiler to increase the temperature of raw water supplied directly from the water supply tank or after preheating, raw water heat-exchanged at a constant temperature is supplied to the hot water tank and heated by the boiler to facilities or places of use. are supplied

However, although the conventional waste heat recovery system as described above can increase energy efficiency to a certain extent in that waste gas is utilized, there is a limit to supplying water at an appropriate temperature according to seasonal factors or boiler operation conditions. That is, problems such as overheating inside the heat exchanger caused by not supplying hot water to the boiler during the initial load of the boiler or supplying water at a higher temperature than necessary in summer can be assumed.

On the other hand, boilers or heat exchangers using waste water heat from hot water discarded among waste heat are used, and in some cases, waste heat recovery facilities for waste heat and waste water heat discarded by exhaust gas are introduced.

However, such a conventional waste heat recovery facility has a problem in that facilities for each waste heat and waste water heat are individually installed, and thus the facility takes up a large space and requires a lot of equipment cost. In addition, conventional waste heat recovery facilities have limitations in improving system efficiency because it is difficult to select the operation of each recovery facility or control simultaneous operation according to seasonal factors or boiler operation conditions.

Republic of Korea Patent Registration No. 10-0856877 (registered on August 29, 2008)

The present invention has been made to solve the above problems,

One purpose is to maximize energy efficiency by simultaneously using wastewater and waste heat to heat the temperature of feedwater above a certain level.

The present invention provides a high-efficiency waste heat recovery device by integrating and systematizing an existing wastewater recovery device, waste heat recovery device, and water supply tank for recovering wastewater and waste heat, thereby saving the installation space of the device and investment cost of facilities. Another purpose is to reduce

Complex waste heat recovery apparatus according to the present invention includes a water supply tank; a first heat exchange unit for circulating and supplying wastewater, and circulating and supplying heated water generated through heat exchange between the water supplied from the water supply tank and waste water heat to the water supply tank; a second heat exchange unit supplying exhaust gas discharged through combustion of the boiler, and circulating and supplying heated water generated through heat exchange between the feed water supplied from the feed water tank and the exhaust heat of the exhaust gas to the feed water tank; and a control valve disposed on a water supply circulation line between the water supply tank and the first heat exchange unit or between the water supply tank and the second heat exchange unit, wherein the control valve is configured to include the first heat exchange unit and the first heat exchange unit. 2 It is characterized in that the water supply of the water supply tank is controlled so that the selective operation or sequential operation of the heat exchange unit is possible.

In the control valve according to the present invention, a first branch line for supplying water to the second heat exchange unit is formed by branching from a first supply line through which water is supplied from the water supply tank to the first heat exchange unit. A first control valve disposed at a branch point between a supply line and the first branch line, and a second supply line through which heated water is supplied from the first heat exchange unit to the water supply tank, and is branched off to the second heat exchange unit. A second branch line for supplying is formed, characterized in that it comprises a second control valve disposed at the branching point of the second supply line and the second branch line.

The control valve according to the present invention is characterized in that the independent operation of the first heat exchange unit is realized by controlling the first and second branch line side valves to be closed by the first control valve and the second control valve. .

The control valve according to the present invention is characterized in that the independent operation of the second heat exchange unit is implemented by controlling the first branch line-side valve to be opened by the first control valve.

The control valve according to the present invention controls the first control valve to close the first branch line-side valve and simultaneously opens the second branch line-side valve to the second control valve, thereby controlling the first and second branch line-side valves. It is characterized in that the sequential operation of the heat exchange unit is realized.

The water supply tank according to the present invention is characterized in that a level gauge for detecting the water supply level and a temperature sensor for detecting the water supply temperature are further provided.

After the selective or sequential operation of the first and second heat exchange units according to the present invention, when the water supply temperature detected by the temperature sensor is higher than the set temperature and the water supply level detected by the level gauge is higher than the set water level It is characterized in that the supply of water to the.

According to the present invention, when the water supply temperature sensed by the temperature sensor is below the set temperature and the water supply level detected by the level gauge is below the set water level, the first and second heat exchange units are selectively operated or sequentially operated. It is characterized by controlling circulation.

The complex waste heat recovery apparatus according to the present invention can maximize energy efficiency by heating the temperature of feed water to a certain level or higher by simultaneously using waste water and waste heat.

In addition, the present invention can provide a highly efficient waste heat recovery device by integrating the existing wastewater recovery device, waste heat recovery device, and water supply tank into one system for recovering wastewater and waste heat, thereby saving the installation space and facilities of the device. investment cost can be reduced.

In addition, the present invention increases the water supply temperature, so that it can be used for hot water supply according to the set temperature or for stable water supply to energy devices (boilers, etc.).

In addition, the present invention not only does not require a lot of time to preheat the water supply temperature at the beginning of operation in the case of an energy device (boiler, etc.) through increased energy efficiency, but also reduces fuel consumption by heating the water supply and supplying it at a certain temperature or higher. Savings and costs can be reduced.

In addition, the present invention can maximize operation efficiency by maintaining a stable supply water temperature through sequence control through an electromagnetic valve and a temperature sensor.

1 is a system diagram showing a complex waste heat recovery device according to the present invention;
2 is a control flow chart showing selective operation of first and second heat exchange units in the complex waste heat recovery device according to the present invention;
3 and 4 are schematic diagrams showing the selective operation of the first and second heat exchange units according to FIG. 2;
5 is a control flow chart showing the sequential operation of first and second heat exchange units in the complex waste heat recovery device according to the present invention;
FIG. 6 is a system diagram illustrating the sequential operation of first and second heat exchange units according to FIG. 5;

In order to explain the present invention and the operational advantages of the present invention and the objectives achieved by the practice of the present invention, the following describes a preferred embodiment of the present invention and references it.

First, the terms used in this application are used only to describe specific embodiments, and are not intended to limit the present invention, and singular expressions may include plural expressions unless the context clearly indicates otherwise. In addition, in this application, terms such as "comprise" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other It should be understood that the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof is not precluded.

In describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

In the present specification, wastewater may include hot water or high-temperature condensate after use discarded from factories or buildings, and may include wastewater discarded after use in various forms. In addition, waste heat is a concept that can use exhaust gas generated from an energy device such as a boiler as a heat source, such as exhaust heat of exhaust gas generated during combustion of a boiler in an energy device and a facility corresponding thereto.

1 to 3, the combined waste heat recovery device (WHR) according to the present invention includes a water supply tank 10, a first heat exchange unit 20, a second heat exchange unit 30, and a control valve 40 ) is composed of.

As shown in FIGS. 1 to 6, the water supply tank 10 according to the present invention stores raw water to supply fluid to a device such as a boiler for supplying steam or hot water by heating the fluid.

Such a water supply tank 10 is provided with a raw water inlet 11 connected to the raw water supply line RL for supplying raw water, and water supply connected to the water supply line SL to supply raw water to a boiler or a place of use. An outlet 13 is provided. In this case, raw water is supplied to the water supply tank 10 through the raw water inlet 11 through the water softener. In addition, the water supply tank 10 is provided with a first inlet 15 and a first outlet 17 for the first heat exchange unit 20, and a second inlet 19 for the second heat exchange unit 30. do. In addition, the water supply tank 10 is provided with a level gauge 50 for detecting the water supply level, and a temperature sensor 60 (PT sensor) for detecting the water supply temperature of the water supply tank 10 is provided.

As shown in FIG. 1, between the water supply tank 10, the first heat exchange unit 20, and the second heat exchange unit 30 according to the present invention, the first heat exchange unit 20 is supplied from the water supply tank 10 for water supply. A first supply line L1 for supplying raw water to and a second supply line L2 for supplying heated water from the first heat exchange unit 20 to the water supply tank 10 are disposed. In addition, a third supply line (L3) for supplying heated water from the second heat exchange unit 30 to the water supply tank 10 is disposed.

Here, the heated water supplied to the water supply tank 10 through the second supply line L2 means heated water through heat exchange between waste water heat and feed water by the first heat exchange unit 20 . In addition, the heated water supplied to the water supply tank 10 through the third supply line L3 is heated water through heat exchange between the exhaust heat and the supplied water by the second heat exchange unit 30, or the first heat exchange unit 20 The heating water heated by the waste water heat and supplied to the second heat exchange unit 30 by branching from the second supply line L2 includes the heating water heated again by the exhaust heat.

In particular, in order to supply water from the first supply line (L1) to the second heat exchange unit (30), the first branch line (D1) branching from the first supply line (L1) and connected to the second heat exchange unit (30) is are provided In addition, a second branch line (D2) branched from the second supply line (L2) and connected to the second heat exchange unit (30) in order to supply heating water from the second supply line (L2) to the second heat exchange unit (30). ) is provided.

In addition, a control valve 40 is provided at each branch point in the first and second branch lines D1 and D2 from the first and second supply lines L1 and L2. In this case, the control valve 40 The first control valve 41 disposed at the branching point of the first supply line L1 and the first branch line D1, and the branched point of the second supply line L2 and the second separation line D2. It is composed of a second control valve 43 to be.

Hereinafter, the heated water generated through heat exchange between the feed water supplied from the feed water tank 10, the waste water heat of the first and second heat exchange units 20 and 30 or/and the exhaust heat and the feed water is transferred to the feed water tank 10. Supply, and in this process, the control process for selection or sequential operation of the first and second heat exchange units 20 and 30 is performed with the first to third supply lines L1, L2, and L3 and the first and second heat exchange units 20 and 30. An implementation example through the two branch lines D1 and D2 and the control valve 40 will be described in detail with reference to the accompanying drawings.

First, as shown in FIGS. 1 to 3, the first heat exchange unit 20 according to the present invention introduces wastewater, generates heated water through heat exchange between the introduced wastewater heat and raw water, and then discharges the wastewater. A supply line (WL) is provided.

That is, the first heat exchange unit 20 is a shell & tube type, and wastewater is introduced through the wastewater supply line (WL), that is, the shell side, flows inside the shell, and then is discharged through the shell side. One end of the bundled tube arranged inside the shell is provided with a first inlet 21 through which raw water supplied from the first outlet 17 of the water supply tank 10 flows in through the first supply line L1, and the other end has After the first outlet 23 is formed to exchange heat with the waste water heat, the generated heated water is discharged and introduced into the first inlet 15 of the water supply tank 10 through the second supply line L2. In this case, the first and second control valves 41 and 43 are implemented by controlling the valves on the side of the first and second branch lines D1 and D2 to be closed.

That is, the first heat exchange unit 20 heat-exchanges wastewater heat with the raw water introduced from the water supply tank 10 and supplies the heated water generated through the heat exchange to the water supply tank 10 so that the raw water in the water supply tank 10 is kept at a constant temperature. It can be heated or preheated with a furnace so that it can be stored. This can improve energy efficiency by recovering wastewater by using it as a heat source for heat exchange.

Next, as shown in FIGS. 1, 2 and 4, the second heat exchange unit 30 according to the present invention receives the exhaust heat of the exhaust gas generated through combustion of the boiler and heats it through heat exchange between the exhaust heat and raw water. After generating water, a waste heat supply line HL for discharging waste heat is provided.

That is, in the second heat exchange unit 30, raw water from the first outlet 17 of the water supply tank passes through the first supply line L1 and the first branch line D1 as shown in FIG. 31) enters. In this case, the first control valve 41 controls the supply of raw water from the first supply line L1 to the first branch line D1 by opening the valve on the side of the first branch line D1. The raw water introduced into the second inlet 31 of the second heat exchange unit 30 is heated through heat exchange with waste heat, and the heated water is heated from the second outlet 33 through the third supply line L3. It is configured to flow into the second inlet 19 of the water supply tank 10. In this case, the first control valve 41 is implemented by controlling the valve on the side of the first branch line D1 to be opened.

That is, the second heat exchange unit 30 heat-exchanges waste heat with the raw water introduced from the water supply tank 10 and supplies the heated water generated through the heat exchange to the water supply tank 10 so that the raw water in the water supply tank 10 is kept at a constant temperature. It can be heated or preheated with a furnace so that it can be stored. This can increase energy efficiency by recovering the exhaust gas generated by combustion of the boiler as a heat source for heat exchange without discharging it into the air as it is.

2 to 4 are implementation examples for selectively driving the first heat exchange unit 20 and the second heat exchange unit 30 as described above.

2 is a control method for selectively operating the first and second heat exchange units 20 and 30. First, the temperature sensor 60 detects the temperature of the water supplied in the water supply tank 10, and the level gauge ( 50) detects the water level in the water supply tank 10. When the detected water supply temperature and water supply level are below the set temperature and below the set water level (90%), the first and second heat exchange units 20 and 30 are selectively driven as shown in FIG. 3 or 4 .

2 and 3 show a case where the first heat exchange unit 20 is operated independently, and the first and second branch lines D1 and D2 in the first and second control valves 41 and 43 ) side valves are simultaneously closed to block supply of raw water and heating water to the second heat exchange unit 30 . Therefore, raw water is supplied to the first heat exchange unit 20 through the first supply line L1, and heated water from the first heat exchange unit 20 is supplied to the water supply tank 10 through the second supply line L2. By being circulated, the first heat exchange unit 20 operates alone.

2 and 4 show a case in which the second heat exchange unit 30 is operated independently, by opening the valve on the first branch line D1 side of the first control valve 41, the second heat exchange unit ( 30) to supply raw water. Therefore, raw water is supplied to the second heat exchange unit 30 through the first supply line L1 and the first branch line D1, and the heated water from the second heat exchange unit 30 passes through the third supply line L3. The second heat exchange unit 30 is operated alone by being supplied to the water supply tank 10 and circulated through the water supply tank 10 .

As such, after selectively operating the first and second heat exchange units 20 and 30, when the water supply temperature of the water supply tank 10 detected by the temperature sensor 60 is higher than the set temperature, water is supplied to the user. . In addition, the water supply level is sensed through the level gauge 50, and when the water supply level is higher than the set water level (90%), it is supplied to the place of use. However, if both the feed water temperature and the feed water level are not satisfied, as described above, the first heat exchange unit 20 or the second heat exchange unit 30 is selectively operated so that the feed water exchanges heat with waste water heat or waste heat to meet the above conditions (feed water temperature and water supply level) is circulated to satisfy.

Meanwhile, as shown in FIGS. 5 and 6, in the present invention, it is possible to control the first and second heat exchange units 20 and 30 to operate sequentially, which will be described in detail below.

First, as shown in FIGS. 5 and 6, when the temperature sensor 60 and the level gauge 50 detect the water supply temperature and the water supply level and do not satisfy the set temperature and the set water supply level, respectively, the first and second heat exchange The units 20 and 30 are controlled to operate sequentially.

To this end, first, the first control valve 41 closes the valve on the side of the first branch line D1 to block raw water from flowing into the second heat exchange unit 30 through the first branch line D1, Raw water is supplied to the first heat exchange unit 20 to generate primary heating water through heat exchange between the raw water and waste water heat. Next, the second control valve 43 opens the valve on the side of the second branch line D2 so that the primary heating water can be supplied to the second heat exchange unit 30 through the second branch line D2, The primary heating water supplied to the second heat exchange unit 30 is heated again through heat exchange with waste heat and supplied to the supply tank as secondary heating water through the third supply line L3. In this way, water supply is circulated through the sequential operation of the first and second heat exchange units 20 and 30. At this time, the temperature sensor 60 and the level gauge 50 detect the water supply temperature and the water supply level so that the water supply temperature is When the set temperature is higher or the water supply level is higher than the set water level (90%), water is supplied to each user. However, if both the feed water temperature and feed water level are not satisfied, the first and second heat exchange units 20 and 30 are sequentially operated as described above so that the feed water exchanges heat with waste water heat and waste heat to achieve the above conditions (feed water temperature and feed water level). ) is cycled to satisfy

Meanwhile, various operation methods such as selective operation or sequential operation of the first and second heat exchange units according to the present invention are possible. For example, in the case of selective operation of the first and second heat exchange units, the first heat exchange unit using relatively low-temperature wastewater is operated first, and after operation, if the above conditions are not satisfied, the first heat exchange unit using higher-temperature waste heat is operated. 2 It is possible to generate heated water by operating the heat exchange unit. Also, since low-temperature water having a relatively low temperature can be used in summer, it is possible to operate only the first heat exchange unit.

In addition, when high-temperature water is required, such as in winter, the first and second heat exchange units are sequentially operated to heat or preheat the water supplied primarily by the first heat exchange unit using relatively low-temperature wastewater, It is also possible to rapidly increase the temperature of the water supply by secondarily heating the primary heated water by the second heat exchange unit using exhaust heat and then supplying the heated water.

That is, the selection or sequential operation of the first and second heat exchange units can maximize energy efficiency by operating an operation method by setting conditions corresponding to the usage environment or seasonal factors.

The composite waste heat recovery device (WHR) according to the present invention configured as described above can maximize energy efficiency by heating the temperature of the feed water to a certain level or more by using waste water and waste heat at the same time. In addition, it is possible to provide a highly efficient waste heat recovery device by integrating the existing wastewater recovery device, waste heat recovery device, and water supply tank into one system to recover wastewater and waste heat, and through this, it is possible to save the installation space of the device and the investment cost of the facility. can save

Furthermore, by raising the water supply temperature, it is possible to use it for hot water supply according to the set temperature or for stable water supply to energy devices (boilers, etc.). In the case of energy devices (boilers, etc.) through increased energy efficiency, not only does it not take much time to preheat the water supply temperature at the beginning of operation, but it also reduces fuel consumption and costs by heating the water supply and supplying it at a certain temperature or higher. can reduce

In the drawings of FIGS. 1, 3, 4, and 6, the non-explained numeral '70' is disposed on the water supply supply line (SL), the first supply line (L1), and the waste water supply line (WL) as a pump to supply water to It will perform the smooth supply of wastewater.

As such, the present invention has been described with reference to one embodiment shown in the drawings, but this is only exemplary, and those skilled in the art can make various modifications and equivalent other embodiments therefrom. will understand

Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

WHR: Complex waste heat recovery device
L1: first supply line L2: second supply line
L3: 3rd supply line
D1: 1st branch line D2: 2nd branch line
HL: waste heat supply line WL: waste water supply line
SL: water supply line RL: raw water supply line
10: water supply tank
11: raw water inlet 13: water supply outlet
15: first inlet 17: first outlet
19: second inlet
20: first heat exchange unit
21: first entrance 23: first exit
30: second heat exchange unit
31: second entrance 33: second exit
40: control valve
41: first control valve 43: second control valve
50: Level Gauge
60: temperature sensor
70: pump

Claims (8)

Water supply tank (10);
A first heat exchange unit 20 for circulating and supplying wastewater, and circulating and supplying heated water generated through heat exchange between the water supplied from the water supply tank 10 and heat of waste water to the water supply tank 10;
Exhaust gas discharged through combustion of the boiler is supplied, and heating water generated through heat exchange between the feed water supplied from the feed water tank 10 and the exhaust heat of the exhaust gas is circulated and supplied to the feed water tank 10. 2 heat exchange units (30); and
A control valve 40 disposed on a water supply circulation line between the water supply tank 10 and the first heat exchange unit 20 or between the water supply tank 10 and the second heat exchange unit 30; but,
The control valve 40 controls the water supply of the water supply tank 10 so that the first heat exchange unit 20 and the second heat exchange unit 30 can be operated selectively or sequentially,
The control valve 40 branches from the first supply line L1 through which water is supplied from the water supply tank 10 to the first heat exchange unit 20 to supply water to the second heat exchange unit 30. A first control valve 41 having a first branch line D1 for the first supply line L1 and the first branch line D1 disposed at a branch point,
A second branch line for supplying heated water to the second heat exchange unit 30 by being branched off from the second supply line L2 through which heated water is supplied from the first heat exchange unit 20 to the water supply tank 10 ( D2) is formed and includes a second control valve 43 disposed at a branch point between the second supply line L2 and the second branch line D2,
The control valve 40 controls the valves on the first and second branch lines D1 and D2 to be closed in the first control valve 41 and the second control valve 43, thereby exchanging the first heat. Implementing the independent operation of the unit 20,
The control valve 40 realizes independent operation of the second heat exchange unit 30 by controlling the valve on the side of the first branch line D1 to be opened by the first control valve 41,
The control valve 40 closes the valve on the side of the first branch line D1 in the first control valve 41, and at the same time closes the valve on the side of the second branch line D2 in the second control valve 43. By controlling to open the first and second heat exchange unit 20, 30 of the composite waste heat recovery device, characterized in that for realizing the sequential operation.
delete delete delete delete According to claim 1,
The water supply tank 10 further includes a level gauge 50 for detecting the water supply level and a temperature sensor 60 for detecting the water supply temperature.
According to claim 6,
After the selective or sequential operation of the first and second heat exchange units 20 and 30, the water supply temperature detected by the temperature sensor 60 is higher than the set temperature, and the level gauge 50 senses A complex waste heat recovery device, characterized in that for supplying water to the place of use when the water supply level is higher than the set water level.
According to claim 7,
When the water supply temperature sensed by the temperature sensor 60 is below the set temperature and the water supply level detected by the level gauge 50 is below the set water level, the first and second heat exchange units 20 and 30 A composite waste heat recovery device characterized in that it controls the circulation of feed water to operate selectively or sequentially.

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