KR20100127917A - System for reclaiming waste heat from boiler - Google Patents

Abstract

PURPOSE: A waste heat recovery system of a closed-loop boiler is provided to accelerate the combustion of a burner in the boiler by heat-exchanging condensate with a heat exchanger for preheating. CONSTITUTION: A waste heat recovery system of a closed-loop boiler(210) comprises a supply pipe, a recovery pipe, a preheating heat exchanger(270), and a cooling heat exchanger(280). The closed-loop boiler burns a fuel with a burner(212) and a blower(214) to produce thermal medium. The supply pipe is connected to closed-loop boiler and supplies the thermal medium to a use place. The recovery pipe collects the condensate, which is created by condensing the thermal medium used in the use place, to the closed-loop boiler. The preheating heat exchanger is connected to the recovery pipe through a first condensate supply pipe(272) and heats low-temperature exterior air drawn by a blower to the specified temperature. The cooling heat exchanger is connected to the preheating heat exchanger through a second condensate supply pipe(282) and heats the condensate heat-exchanged by the preheating heat exchanger to the temperature of the condensate collected through the recovery pipe.

Description

System for Reclaiming Waste Heat From Boiler}

The present invention relates to a waste heat recovery system of a closed circuit boiler. More specifically, the high-temperature exhaust gas and the heat medium generated when producing a heat medium such as steam and hot water of high temperature and high pressure are heat-exchanged through heat use to recover the high-temperature condensed water to utilize the waste heat of the exhaust gas and the condensate. The present invention relates to a waste heat recovery system of a closed circuit boiler, which maximizes the efficiency of waste heat, and promotes combustion of the burner of the closed circuit boiler to improve combustion efficiency.

In general, a boiler is a device that supplies hot water or steam to a heat source by burning fuel such as petroleum and coal. Among them, in the case of indoor heating, in a steam boiler, a boiler is used. The generated steam is transported by the steam pressure to dissipate the latent heat that is retained after heat exchange with the indoor air at the place where the indoor heat is used, and the condensate and some waste steam that passed through the steam trap are returned to the recovery tank through the recovery pipe and the remaining latent heat And then become condensate and fed to the boiler.

On the other hand, when using the heat of steam directly, such as in the case of a heat source such as a sauna, a laundry room or a food factory for deodorization process, steam is directly supplied to the target object to use heat, and the remaining steam in the supply pipe is recovered through a recovery tank. The steam supplied to the target object loses latent heat, turns into condensate, and is drained through a separately installed collecting pipe.

In general, when steam is used, only a portion of latent heat of the heat retained by steam pressure is used as heat for use, and most of the remaining latent heat and sensible heat are wasted into the atmosphere. It is used as a supplementary water.

1 is a view showing a waste heat recovery system of a closed circuit boiler according to the prior art.

As shown, the waste heat recovery system of the closed circuit boiler according to the prior art is a closed circuit boiler 110 for producing a heat medium such as steam, hot water of high temperature and high pressure, the flue 120 for discharging the high-temperature high-pressure waste gas generated during the heat medium production. And a stack 130, a supply pipe 140 connected to the closed circuit boiler 110 to supply a heat medium, a sauna, a laundry room or a deodorizer connected to the supply pipe 140 using a heat medium produced in the closed circuit boiler 110. It is configured to include a recovery pipe 160 that is condensed by heat exchange to the heat use destination 150 and the heat use destination 150, such as a food factory for the process is recovered to the closed circuit boiler 110.

The waste heat recovery system of the closed circuit boiler according to the prior art configured as described above drives the burner 112 and the blower 114 to produce a heat medium in the closed circuit boiler 110, and the produced heat medium is heat used through the supply pipe 140. When the heat medium 150 supplies the heat medium to each target object at the heat using place 150, and the heat medium supplied is condensed by heat exchange by low temperature external air and converted into high temperature condensate, the condensate is returned to the return pipe. It is configured to be recovered and reused in the closed circuit boiler 110 through 160.

However, in the waste heat recovery system 100 of the closed circuit boiler according to the prior art, since the air supplied by the blower 114 provides low temperature external air when the closed circuit boiler 110 is driven, the combustion action of the fuel is insufficient. Emissions of unburned gas were high, and fuel utilization was also low.

In addition, the high temperature exhaust gas discharged after producing the heat medium in the closed-circuit boiler 110 is discharged to the outside through the flue 120 and the chimney 130 to eventually waste energy due to the loss of heat contained in the exhaust gas There was a problem that resulted.

On the other hand, in order to recover the waste heat of the above-described high-temperature exhaust gas has been developed a variety of waste heat recovery system 100 to install a separate waste heat recovery device in the closed circuit boiler 110 or the flue 130, most of which is a closed circuit boiler ( The system that recovers and reuses the exhaust gas itself discharged from 110 is applied.

However, even if the waste heat is reused by recovering the exhaust gas itself, the internal pressure of the closed circuit boiler 110 is increased, thereby reducing the durability of the closed circuit boiler 110. The waste heat recovery device is separately installed in the closed circuit boiler 110. Since there is a way that the production and installation cost of the closed-circuit boiler 110, and the maintenance cost of the closed-circuit boiler 110 has been a problem.

In order to solve this problem, the present invention installs a heat exchanger for supplying air to the burner and the blower, thereby recovering the combustion operation of the burner of the closed circuit boiler by heating the outside air of a low temperature to a predetermined temperature while the condensed water recovered is exchanged by the heat exchanger. By promoting the combustion efficiency by maximizing the minimization of the emission of unburned gas, as well as to improve the fuel utilization.

In addition, the present invention by installing the heat exchanger for exhaust gas cooling in the year that the exhaust gas of the high temperature is discharged, the condensed water heat exchanged through the air supply preheating heat exchanger is heat-exchanged by the temperature of the exhaust gas is raised to a predetermined temperature, By returning to the closed-circuit boiler, it is possible to maximize the efficiency of the use of waste heat in the closed-loop boiler as well as to minimize the heat loss.

In addition, the present invention by providing a waste heat recovery system for recovering waste heat through heat exchange of the condensate is recovered, it is possible to reduce the production cost and installation cost of the closed circuit boiler, as well as to reduce the maintenance cost of the closed circuit boiler. There is a purpose.

In order to achieve the above object, the present invention is a closed-loop boiler for producing a heat medium by burning fuel by a burner and a blower; A supply pipe connected to the closed circuit boiler to supply a heat medium to a heat using place; A recovery pipe for recovering condensed water condensed with the heat medium used in the heat use to the closed-loop boiler; An air supply preheating heat exchanger installed in connection with the blower and connected with the recovery pipe and the first condensate water supply pipe so as to exchange heat with the condensate so that the temperature of the low temperature external air sucked by the blower is increased to a predetermined temperature; And an exhaust discharged from the closed-circuit boiler so that the temperature of the condensed water heat exchanged by the air supply preheating heat exchanger and the second condensed water supply pipe is raised to the temperature of the condensed water recovered through the recovery pipe. It provides a waste heat recovery system of a closed-circuit boiler comprising a heat exchanger for cooling the exhaust gas so that heat exchange with the gas.

In addition, the second condensate water supply pipe connected to the heat exchanger for cooling the exhaust gas further comprises a condensate control means for adjusting the supply amount of the condensate heat exchanged by the air supply preheating heat exchanger, in particular the condensate control The means is provided with a solenoid valve for controlling the supply amount of the condensate supplied to the heat exchanger for cooling the exhaust gas, a return valve for temporarily actuating by a malfunction of the solenoid valve, and a front of the solenoid valve to be supplied to the return valve side. It provides a waste heat recovery system of a closed-circuit boiler, characterized in that it comprises a manual valve installed in the rear respectively.

In addition, the present invention is the low-temperature outside air sucked by the blower is raised to a temperature of 240 ℃ ~ 260 ℃ by the air supply preheating heat exchanger, the temperature of the condensate heat exchanged through the air supply preheating heat exchanger is 80 ℃ It is lowered to ~ 100 ℃ is supplied to the exhaust gas cooling heat exchanger, the temperature of the exhaust gas discharged from the closed loop boiler is discharged to a temperature of 350 ℃ ~ 370 ℃, the exhaust gas cooling is supplied to the heat exchanger The condensed water is heat exchanged with the exhaust gas is raised to 300 ℃ ~ 319 ℃ to provide a waste heat recovery system of the closed circuit boiler, characterized in that recovered to the closed circuit boiler.

As described above, according to the present invention, by condensing the heat of the condensed water by a heat exchanger for supplying air to the burner and the blower to promote combustion of the burner of the closed circuit boiler, the combustion efficiency is maximized, as well as minimizing the emission of unburned gas. This has the effect of maximizing the utilization of fuel.

In addition, according to the present invention, the condensed water heat exchanged through the air supply preheating heat exchanger is heat exchanged by the exhaust gas cooling heat exchanger is recovered to the closed circuit boiler, it is possible to maximize the efficiency of the waste heat of the closed circuit boiler, as well as heat loss It has the effect of minimizing.

In addition, according to the present invention, by providing a waste heat recovery system for recovering waste heat through the heat exchange of the condensate is recovered, it is possible to reduce the production cost and installation cost of the closed-circuit boiler, and also to reduce the maintenance cost of the closed-loop boiler It works.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the elements of each drawing, it should be noted that the same reference numerals are used to refer to the same elements even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a view showing a waste heat recovery system of a closed circuit boiler according to a preferred embodiment of the present invention, Figure 3 is a view showing a process of recovering waste heat through the waste heat recovery system of a closed circuit boiler according to a preferred embodiment of the present invention. .

As shown, the waste heat recovery system of the closed circuit boiler according to the present invention is a closed circuit boiler 210, a closed circuit boiler 210 and the heat use 250 to produce a heat medium or heat medium oil, such as steam and hot water of high temperature and high pressure, respectively. Supply conduit 240 connected to transfer the heat medium to the heat source 250, the first condensate recovery pipe 260 to recover the condensed water condensed by the heat medium used in the heat source 250 to the closed circuit boiler 210, closed circuit It is installed in connection with the blower 214 of the boiler 210 and the exhaust condensate recovered from the first condensate return pipe 260 and the air supply preheating heat exchanger 270, the closed-circuit boiler 210 is exhausted and the external low-temperature air heat exchanged It is configured to include an exhaust gas cooling heat exchanger 280 for exchanging the exhaust gas and the condensate.

The closed circuit boiler 210 heats the condensed water in the closed circuit boiler 210 while burning the fuel through a burner 212 for burning fuel and a blower 214 for supplying external air to improve fuel combustion efficiency. Produces a heat medium such as steam or hot water, and the produced heat medium is to be supplied to the target object of the heat source 250 through the supply pipe 240.

In such a closed circuit boiler 210, the condensate recovered through the first condensate return pipe 260 and external air in a low temperature state sucked from the blower 214 are heat-exchanged so that the temperature of the low temperature external air is higher than or equal to a predetermined temperature. The air supply preheating heat exchanger 270 is connected to the blower 214 to maximize the combustion efficiency by promoting the fuel combustion action of the burner 212 to minimize the emission of unburned gas.

Here, the air supply preheating heat exchanger 270 is one end of the first condensate recovery pipe 260 and the branch pipe (so that the condensed water recovered through the first condensate water recovery pipe 260 is exchanged with the low-temperature outside air) 290 is connected, and the other end is connected to the air supply preheating heat exchanger 270 to form a first condensate water supply pipe 272 for supplying the preheating air supply.

For example, the heat medium supplied through the supply pipe 240 is converted into a condensate state having a temperature of about 300 ° C. to 319 ° C. while being used for a target object for heat use, and the converted condensate is the first condensate to save energy. Recovered through the recovery pipe 260, at this time, through the air supply preheating heat exchanger 270 and the first condensate supply pipe 272 connected to the first condensate recovery pipe 260 270 is also supplied to the heat exchange with the low-temperature outside air sucked by the blower 214 to raise the temperature of the outside air to about 240 ℃ ~ 260 ℃ and then supply to the burner 212, burner 212 It is possible to maximize the combustion efficiency and promote the combustion of fuel, and minimize the emission of unburned gas.

In addition, the closed loop boiler 210 is connected to the flue 220 to exhaust the exhaust gas passing through the combustion chamber, the exhaust gas is discharged through the flue 220, the discharged exhaust gas is installed at one end of the flue 220 It is released to the outside by the stack 230 which is.

In the flue 220 of the closed-loop boiler 210 such that the heat exchange between the exhaust gas and the condensate in the state cooled to a predetermined temperature through the heat exchanger 270 for the air supply is increased to increase the temperature of the condensate to close the boiler 210 Exhaust gas cooling heat exchanger 280 to be recovered is installed.

Here, the exhaust gas cooling heat exchanger 280 is an air supply preheating heat exchanger 270 through a second condensate supply pipe 282 connecting the air supply preheating heat exchanger 270 and the exhaust gas cooling heat exchanger 280. The heat exchanged condensed water is supplied by the heat exchanger and is connected to the heat source 250 and the closed circuit boiler 210 so that the heat-condensed condensed water is recovered to the closed circuit boiler 210 through the exhaust gas cooling heat exchanger 280. The second condensate return pipe 260 and the second condensate return pipe 284 connected through the branch pipe 290 is provided.

That is, the temperature of the condensed water heat exchanged through the air supply preheating heat exchanger 270 is lowered to a temperature of about 90 ° C. between about 309 ° C. and about 80 ° C. to 100 ° C. between about 300 ° C. and 319 ° C. When supplied to the exhaust gas cooling heat exchanger 280 through the condensed water supply pipe 282, the condensed water in the closed loop boiler 210 is heated in the combustion chamber, and then about 350 ℃ ~ 370 ℃ about about 350 ℃ through the flue (220) Heat exchange is performed with the exhaust gas exhausted to a temperature of 360 ° C to recover the second condensate while being raised to about 309 ° C, which is the temperature of the hot condensate supplied to the closed circuit boiler 210 through the first condensate recovery pipe 260 It is supplied to the closed circuit boiler 210 by the pipe 284.

On the other hand, the second condensate water supply pipe 282 is provided with condensate control means 310 for adjusting the amount of condensate supplied.

Condensate control means 310 includes a solenoid valve 312 for adjusting the supply amount of the condensate supplied according to the opening and closing amount of the valve, and a return valve 316 to be temporarily operated by the malfunction of the solenoid valve 312, etc. It is composed.

In addition, a manual valve 314 is formed at the front and the rear of the solenoid valve 312, respectively, so that the heat exchanger for cooling the exhaust gas through the second condensate supply pipe 282 when the solenoid valve 312 is replaced or malfunctions. Condensate supplied to 280 is supplied through return valve 316.

In the waste heat recovery system of the present invention configured as described above, the burner 212 and the air supply preheating heat exchanger 270 are connected and installed in order to convert the condensed water into the heat medium through the closed circuit boiler 210. To about 250 ° C., and burns fuel through a blower 214 that sucks the external air whose temperature is raised to produce a heat medium, and the produced heat medium passes through a supply pipe 240 to a heat source 250. To be supplied to each target.

And, through the supply pipe 240, the heat medium is used for each target object of the heat using place 250, and in contact with the outside air and thus the heat medium is condensed and converted into condensed water, the converted condensate is one surface of the heat using 250 Recovered to the closed circuit boiler 210 through the first condensate recovery pipe 260 connected to the through, the first condensate supply pipe 272 connected to the first condensate recovery pipe 260 by the branch pipe 290. Some of the recovered condensate is supplied to the air supply preheating heat exchanger 270 to perform a primary heat exchange to raise the low temperature external air sucked by the blower 214 to a predetermined temperature.

In addition, the condensed water subjected to the first heat exchange in the air supply preheating heat exchanger 270 is supplied to the exhaust gas cooling heat exchanger 280 through the second condensed water supply pipe 282 while being lowered to about 90 ° C., The condensate is combusted in the combustion chamber in the closed loop boiler 210 and heat exchanged with the exhaust gas discharged to a temperature of about 360 ° C. while the condensate is lowered to a predetermined temperature by the air supply preheating heat exchanger 270 to about 309 ° C. Ascending to and recovered to the closed loop boiler through the second condensate recovery pipe (284).

Such waste heat recovery system of the present invention heats the condensed water by the heat exchanger 270 for the air supply preheating to the burner 212 and the blower 214 to promote combustion of the burner 212 of the closed circuit boiler 210 to burn. By maximizing the efficiency, the emission of unburned gas may be minimized, and the utilization rate of the fuel may be maximized. The condensed water that has been heat-exchanged through the air supply preheating heat exchanger 270 may be transferred to the heat exchanger 280 for cooling the exhaust gas. By heat exchange by the recovery to the closed circuit boiler 210, it is possible to maximize the efficiency of the waste heat of the closed circuit boiler 210, as well as to minimize the heat loss, waste heat recovery to recover the waste heat through the heat exchange of the recovered condensate By providing a system, not only can reduce the production cost and installation cost of the closed circuit boiler 210, but also reduces the maintenance cost of the closed circuit boiler 210 And it is.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 is a view showing a waste heat recovery system of a closed circuit boiler according to the prior art,

2 is a view showing a waste heat recovery system of a closed circuit boiler according to a preferred embodiment of the present invention;

3 is a view showing a process of recovering the waste heat through the waste heat recovery system of the closed circuit boiler according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

210: closed-loop boiler 212: burner

214: blower 220: year

230: stack 240: steam supply piping

250: heat used 260: first condensate return pipe

270: air supply preheating heat exchanger 272: first condensate supply pipe

280: heat exchanger for cooling exhaust gas 282: second condensate supply pipe

284: second condensate recovery pipe 290: branch pipe

310: condensate control means 312: solenoid valve

314: manual valve 316: return valve

Claims (5)

Closed-circuit boiler which burns fuel by burner and blower and produces heat medium; A supply pipe connected to the closed circuit boiler to supply a heat medium to a heat using place; A recovery pipe for recovering the condensed water condensed with the heat medium used in the heat use to the closed-loop boiler; An air supply preheating heat exchanger installed in connection with the blower and connected with the recovery pipe and the first condensate water supply pipe so as to exchange heat with the condensate so that the temperature of the low temperature external air sucked by the blower is increased to a predetermined temperature; And The exhaust gas discharged from the closed-circuit boiler connected to the air supply preheating heat exchanger and the second condensate supply pipe so that the temperature of the condensed water heat exchanged by the air supply preheating heat exchanger is raised to the temperature of the condensate water recovered through the recovery pipe. Heat exchanger for exhaust gas cooling Waste heat recovery system of a closed circuit boiler comprising a. The method of claim 1, Waste heat recovery of the closed-circuit boiler, characterized in that the second condensate water supply pipe connected to the heat exchanger for cooling the exhaust gas further comprises condensate control means for adjusting the supply amount of the condensate heat exchanged by the air supply preheating heat exchanger. system. The method of claim 2, The condensate adjusting means may include a solenoid valve for controlling a supply amount of condensate supplied to the exhaust gas cooling heat exchanger, a return valve to be temporarily operated by a malfunction of the solenoid valve, and the solenoid valve to be supplied to the return valve side. Waste heat recovery system of a closed-circuit boiler, characterized in that it comprises a manual valve installed in the front and rear respectively. The method of claim 1, Low temperature outside air sucked by the blower is raised to a temperature of 240 ℃ ~ 260 ℃ by the air supply preheating heat exchanger, the temperature of the condensate heat exchanged through the air supply preheating heat exchanger drops to 80 ℃ ~ 100 ℃ Waste heat recovery system of a closed-circuit boiler characterized in that it is supplied to the heat exchanger for cooling the exhaust gas. The method of claim 1, The temperature of the exhaust gas discharged from the closed-loop boiler is discharged to a temperature of 350 ℃ ~ 370 ℃, the condensed water which is supplied to the exhaust gas cooling heat exchanger and the heat exchange with the exhaust gas is raised to 300 ℃ ~ 319 ℃ to the Waste heat recovery system of a closed circuit boiler, characterized in that recovered to the closed circuit boiler.

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