KR20220068844A - Boiler to increase exhaust heat recovery efficiency - Google Patents

Abstract

The present invention relates to a boiler for increasing exhaust heat recovery efficiency. More specifically, the boiler for increasing exhaust heat recovery efficiency comprises: a boiler; a water supply tank for supplying water to the boiler; a first economizer installed in an exhaust gas flue to generate first heated water through heat exchange between the supplied water supplied from the water supply tank and exhaust heat; a second economizer installed in the exhaust gas flue and supplying, to the boiler, second heated water generated through heat exchange between the first heated water supplied from the first economizer and exhaust heat; and an air preheater disposed on one side of the first economizer, having combustion air introduced therein, and preheating the combustion air through heat exchange between the first heated water and the combustion air. The present invention maximizes the exhaust heat recovery efficiency by heating the exhaust heat burned and discarded from the boiler by the economizer and by supplying the heated exhaust heat to the boiler, and simultaneously by heating and preheating the combustion air using hot water heated by the economizer. Therefore, the efficiency of the boiler can be increased.

Description

Boiler to increase exhaust heat recovery efficiency

The present invention maximizes exhaust heat recovery efficiency by heating exhaust heat that is burned and wasted from a boiler by an economizer and supplying it to the boiler, and at the same time heating and preheating combustion air using hot water heated in the economizer, thereby maximizing the efficiency of the boiler It relates to a boiler for increasing exhaust heat recovery efficiency that can improve

In general, a boiler has a structure to maximize thermal efficiency by absorbing sensible heat and latent heat of condensation of exhaust gas as useful heat.

In particular, the condensing boiler maximizes this and represents a high-efficiency boiler.

In the prior art of such a large-densing boiler, there is a structure that maximizes thermal efficiency by installing double economizers, which are driven by connecting two economizers in series on the exhaust gas exhaust path of the boiler body, and The effect of supplying low-temperature water to the economizer with a large surface area by adapting to the operating condition of the boiler by selectively controlling the path of the fluid to recover the sensible heat and latent heat of condensation of the exhaust gas from the two economizers according to the exhaust temperature of the exhaust gas It is constructed so that the thermal efficiency can be further increased by trying to

In particular, in the case of a conventional boiler, an air preheater is disposed on the exhaust gas exhaust passage to preheat the air, and it is configured to heat the combustion air through heat exchange and supply it to the burner.

However, when the air preheater is separately installed as in the prior art, there is a problem in that not only the air preheating heat exchanger must be separately manufactured, but also the cost for manufacturing the air preheater is also issued.

In addition, when a separate air preheater is installed, the spatial arrangement structure in the overall boiler structure is complicated and narrow, which may cause problems in space utilization.

Republic of Korea Patent Registration No. 10-1243698 (published on March 8, 2013)

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

The exhaust heat that is burned and discarded from the boiler is heated by the economizer and supplied to the boiler. At the same time, by heating and preheating the combustion air using the hot water heated in the economizer, the exhaust heat recovery efficiency is maximized, thereby improving the efficiency of the boiler. Sleeping has one purpose.

The present invention bypasses the heating feed water flowing into the boiler from the second economizer and air preheater in consideration of the load of the boiler, operating conditions, operating conditions, and seasonal factors to prevent vaporization or low-temperature corrosion inside the heat transfer tube In addition, it is another object to increase the preheating efficiency of combustion air.

A boiler for increasing exhaust heat recovery efficiency according to the present invention includes: a boiler; a water supply tank for supplying water to the boiler; a first economizer installed in the exhaust gas flue to generate first heated water through heat exchange between the supply water supplied from the water supply tank and exhaust heat; a second economizer installed in the exhaust gas flue and configured to supply second heated water generated through heat exchange between the first heated water supplied from the first economizer and exhaust heat to the boiler; and an air preheater disposed on one side of the first economizer to receive combustion air and preheat the combustion air through heat exchange between the first heating water and the combustion air.

A water supply line for supplying water from the water supply tank to the boiler according to the present invention includes a first supply line from the water supply tank to the first economizer, and from the first economizer and the air preheater to the second economizer. It is characterized in that it comprises a second supply line that continues, and a third supply line that leads from the second economizer to the boiler.

It characterized in that it further comprises a first bypass for bypassing the second heated water supplied to the boiler through the third supply line according to the present invention to the water supply tank.

It characterized in that it further comprises a second bypass for bypassing the second heating water supplied to the boiler through the third supply line according to the present invention to the second supply line.

A control valve 60 is further provided on the third supply line according to the present invention to bypass the second heating water to the first bypass or the second bypass, or the first and second bypass. characterized in that

The first economizer and the air preheater according to the present invention are provided with a partition for partitioning a section between each other, and a combustion air flow path for inducing combustion air flowing into and discharged from the air preheater to the boiler on the downstream side of the air preheater. It is characterized in that it is provided.

The heat transfer tubes of the first economizer and the air preheater according to the present invention are characterized in that they are disposed to cross each other through the partition.

The boiler for increasing the exhaust heat recovery efficiency according to the present invention heats exhaust heat that is burned and wasted from the boiler by the economizer and supplies it to the boiler, and at the same time heats and preheats the combustion air using the hot water heated in the economizer, thereby recovering exhaust heat recovery efficiency It is possible to maximize the efficiency of the boiler through this.

In addition, the present invention bypasses the heating feed water flowing into the boiler from the second economizer and air preheater in consideration of the load of the boiler, operating conditions, operating conditions, and seasonal factors to prevent vaporization or low-temperature corrosion in the heat transfer tube. In addition to preventing it, it is possible to increase the preheating efficiency of the combustion air.

In particular, according to the present invention, the first economizer and the air preheater are arranged in such a way that they share a heat transfer tube therein, so that supply water is heated by exhaust heat of exhaust gas, and at the same time, the heated first heated water, that is, hot water, exchanges heat with combustion air. Since it is configured to preheat by warming the combustion air, it is not necessary to separately manufacture the heat transfer tubes constituting the first economizer and the air preheater, thereby reducing manufacturing costs.

In addition, according to the present invention, the amount of heat in water supplied through the air preheater can be immediately restored by recovering exhaust heat of exhaust gas from the first economizer, thereby improving thermal efficiency in terms of thermal management.

1 is a schematic diagram showing a boiler for increasing exhaust heat recovery efficiency according to the present invention;
2 is a schematic diagram showing a first embodiment of a boiler for increasing exhaust heat recovery efficiency according to the present invention;
3 is a schematic diagram showing a second embodiment of a boiler for increasing exhaust heat recovery efficiency according to the present invention;
4 is a schematic diagram showing a third embodiment of a boiler for increasing exhaust heat recovery efficiency according to the present invention.

In order to explain the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, preferred embodiments of the present invention are exemplified below and will be described with reference to them.

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

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 thereof will be omitted.

1 to 4, the boiler for increasing the exhaust heat recovery efficiency according to the present invention includes a boiler 10, a feed water tank 20, a first economizer 30, a second economizer 40, and It is configured to include an air preheater (50).

That is, the boiler 10 according to the present invention is combusted from a burner provided in the boiler 10 to supply feed water from the feed water tank 20 to the boiler 10 while maintaining a constant temperature and discharged through the flue 1 . By utilizing the exhaust heat of the exhaust gas, the economizer, that is, the economizer, heats the feed water through heat exchange between the feed water and the exhaust heat, and supplies hot water at a certain temperature to the boiler 10 .

First, as shown in FIGS. 1 to 4 , the boiler 10 according to the present invention includes a combustion chamber having a fire tube, a water drum formed around the combustion chamber and filled with water, and a burner installed at the entrance of the combustion chamber to generate a flame. do. The exhaust gas generated by the flame heats the water filled in the water drum or generates steam while passing through the pipe as an exhaust passage. At this time, the exhaust gas is normally discharged through the flue 1 through the pipe pipe, but in the boiler 10 according to the present invention, the discharged exhaust gas is not directly discharged through the flue 1, but a plurality of economizers, that is, the second After the first and second economizers 30 and 40 generate hot water at a predetermined temperature through heat exchange with water supply, it is configured to be discharged through the flue 1 . This can increase energy efficiency in that the exhaust gas emitted after combustion is recovered and utilized instead of being thrown away as it is.

In this case, the exhaust gas discharged from the burner is discharged to the flue 1 through the exhaust gas discharge line, and the exhaust gas discharge line may be a duct constituting the flue 1, or may be the flue 1 itself. .

1 to 4 , the feed water tank 20 according to the present invention is supplied with feed water to supply water to the boiler 10 .

The feed water supplied from the water supply tank 20 to the boiler 10 may be directly supplied, but if it is heated to a certain temperature using the exhaust heat of the exhaust gas discharged through the flue 1 and supplied to the boiler 10, energy efficiency And it is possible to increase the efficiency of the boiler (10).

Hereinafter, as described above, an economizer for increasing the temperature of the water supply through heat exchange between the exhaust heat of the exhaust gas discharged through the flue 1 and the water supplied from the water supply tank 20 will be described.

The boiler 10 according to the present invention is provided with a water supply line L to supply water from the water supply tank 20 to the boiler 10 to supply water, between the water supply tank 20 and the boiler 10 . A first economizer 30 , an air preheater 50 , and a second economizer 40 are disposed.

In this case, the water supply line L is a first supply line L1 from the water supply tank 20 to the first economizer 30, and the second economizer 40 from the first economizer 30 and the air preheater 50. ) is composed of a third supply line (L3) leading to the boiler (10) from the second supply line (L2) leading to.

In addition, separate from the water supply line (L), a bypass line is provided to prevent vaporization or low-temperature corrosion inside the economizer heat pipe that may occur depending on the load condition of the boiler 10, operating condition, and seasonal factors. 3 It may be formed branched from the supply line (L3). A detailed description of the bypass line will be described later.

1 to 4, the first economizer 30 according to the present invention is disposed on the downstream side of the exhaust gas flue 1, and water is supplied to the water supply tank 20 through the first supply line L1. supplied from

In this way, the water supplied through the first supply line L1 is heat-exchanged with the exhaust heat of the exhaust gas passing through the flue 1 while passing through the heat transfer tube inside the first economizer 30 to generate the first heated water. The first heated water generated from the first economizer 30 is supplied to the air preheater to exchange heat with combustion air flowing into the air preheater.

1 to 4, the air preheater 50 according to the present invention preheats the first heating water generated from the first economizer 30, that is, hot water and combustion air by heat exchange.

The combustion air preheated by the hot water is supplied to the burner. For this purpose, a combustion air flow path 80 is formed on the downstream side of the air preheater 50, so that the combustion air introduced from the upstream side of the air preheater 50 is heated for the first time. After heat exchange with water, it is guided toward the burner through the combustion air flow path 80 . In this case, it is preferable that the blowing fan 90 is disposed above the air preheater 50 in the drawing to blow the combustion air toward the combustion air flow path 80 and the burner side.

In particular, the air preheater 50 may be disposed on one side of the first economizer 40 , that is, on the left side of the first economizer 30 in the drawing, and may be integrally formed. In this case, the first economizer 30 and the air preheater 50 are provided with a partition portion 70 such as a partition plate to partition the internal space thereof. In the drawing based on the partition plate, the right partition part 70 is disposed on the flue 1, and the left partition part 70 is disposed on the combustion air inlet side.

Also, the heat transfer tubes of the first economizer 30 and the air preheater 50 may be disposed to cross each other through the partition portion 70 . That is, the heat transfer tubes of the first economizer 30 and the air preheater 50 are disposed to penetrate through the partition unit 70 in a zigzag form by connecting a plurality of horizontal tubes and the ends of each horizontal tube.

Therefore, the water supplied from the water supply tank flows into the heat pipe on the side of the first economizer 30 disposed on the right side, and then goes through the heat pipe on the side of the air preheater 50 again to the heat pipe on the side of the first economizer 30. . That is, the first heating water heated by the first economizer 30 passes through the heat transfer tube on the air preheater 50 side and exchanges heat with the combustion air to preheat the combustion air.

As described above, the first economizer 30 and the air preheater 50 are disposed in a form that shares the heat transfer tube therein, so that the feed water is heated by the exhaust heat of the exhaust gas, and at the same time, the heated first heating water, that is, the hot water is the combustion air. Since it is configured to heat and preheat the combustion air by exchanging heat with it, there is no need to separately manufacture the heat transfer tubes constituting the first economizer 30 and the air preheater 50 , thereby reducing manufacturing costs. In particular, since the amount of heat from the water supplied through the air preheater 50 can be immediately restored by recovering the exhaust heat of the exhaust gas, there is an advantage in that thermal efficiency can be improved in terms of thermal management.

In addition, by integrating the first economizer and the air preheater to form a compact structure, the arrangement structure of the boiler can also be configured compactly, thereby obtaining the advantage of increasing space utilization.

1 to 4, the second economizer 40 according to the present invention is disposed on the upstream side of the exhaust gas flue 1, and water is supplied to the first economizer 30 through the second supply line L2. ) and the first heated water is supplied from the air preheater 50 .

The water supplied through the second supply line (L2) passes through the heat transfer tube inside the second economizer (40) and exchanges heat with the exhaust heat of the exhaust gas passing through the flue (1) to generate the second heated water. The second heated water generated from the second economizer 40 is supplied to the boiler 10 through the third supply line L3.

Furthermore, in the boiler 10 according to the present invention, the economizer is a type of heat exchanger and is provided with an internal heat transfer tube. When the feed water stays there for a long time depending on the load of the boiler 10 or the operating state Noise or loss of heat pipe due to vaporization may be a problem. In addition, if the temperature around the heat pipe is low, damage to the heat pipe due to low-temperature corrosion may be a problem, and in some cases, especially in winter, a lot of heat is lost by the cooled combustion air, so the temperature of the first heating water is relatively low. It is supplied to the second economizer, which may cause problems such as lowering thermal efficiency.

In the present invention, in order to solve this problem, the bypass line B may be configured to branch and bypass the third supply line L3 for supplying feed water from the second economizer 40 to the boiler 10 .

This bypass line (B) is a first bypass (B1) for diverting water supply from the third supply line (L3) to the water supply tank (20), and the second supply line (L3) from the third supply line (L3). It is configured to include a second bypass (B2) for diverting the water supply to L2).

In addition, the bypass line (B) has a control valve 60 for supplying water to the first bypass (B1) or the second bypass (B2), or the first and second bypasses (B1) and (B2). Preferably, the control valve 60 is configured as a four-way valve to control water supply.

The bypass line (B) configured as described above is the first bypass (B1) or the second bypass (B2), or the first and second The bypass (B1) (B2) is controlled so that the water supply can be bypassed.

Hereinafter, water supply and water supply amount control by the bypass line B and the control valve 60 in each situation will be described with reference to the accompanying drawings.

First, the illustration of FIG. 1 shows the supply of feed water in a situation in which the boiler 10 is normally operated, as a bypass line (B), and more specifically, the first and second bypasses (B1) and (B2) (with a dotted line). indicated), and water supply is not supplied.

Next, as shown in FIG. 2 , the second bypass B2 is closed by the control valve 60, and the first bypass B1 is open, and the water supply bypassing the third supply line L3 is water supply. This is the case where it flows into the tank 20 . This is a case in which the supply of water supply to the boiler 10 is limited at the initial load of the boiler 10. However, in this case, when the water supply to the boiler 10 is limited and the feed water stays inside the heat transfer tube of the second economizer 40 for a long time Vaporization may occur due to overheating of the feedwater. In addition to the noise and vibration caused by the water hammer. Damage to the heat pipe may be a problem. Therefore, in order to solve this problem, the water supply from the third supply line (L3) is bypassed, and at the same time, the control valve 60 opens the first bypass (B1) side so that the water supply can be introduced into the water supply tank (20). let it be

In addition, the first bypass (B1) is closed by the control valve (60), the second bypass (B2) in the state shown in FIG. 3 is the second bypass (B2) in the open state, the supply water bypassed from the third supply line (L3) is the second This is a case in which it is supplied to the supply line L2. This is a case in which low-temperature corrosion of the second economizer 40 is a problem, or a case in which thermal efficiency is a problem due to cooling in winter, that is, cooled combustion air. In this case, the second heated water heated by the second economizer 40 is supplied to the second supply line L2 through which the first heated water having a relatively low temperature is passed, and the first heated water and the second heated water are mixed with each other. may be supplied to the second economizer 40 . In this way, the temperature of the first heated water supplied to the second economizer 40 is raised and supplied to increase the temperature of the second heated water more rapidly, thereby preventing low-temperature corrosion of the heat transfer tube, or the amount of heat lost by the cooled combustion air It is possible to increase the thermal efficiency by supplementing with the second heating water that is bypassed and supplied.

4 shows a case of bypassing by controlling and distributing the amount of water supplied to the first and second bypasses B1 and B2 by the control valve 60 . This control may be more effective than the embodiment of FIG. 2 , that is, when the temperature of the second heating water needs to be rapidly increased in the embodiment corresponding to FIG. 3 . As in the embodiment of FIG. 3 , the temperature of the second heated water is rapidly increased, and the bypass flow rate from the second economizer 40 is reduced to a desired predetermined temperature by the first and second bypasses (B1) and (B2). This is to control the temperature of the water supply by distributing and controlling the However, as in the embodiment of FIG. 2 , when vaporization occurs inside the heat transfer tube of the second economizer 40 , the second heating water branched to the second supply line L2 is supplied through the second bypass B2. 2 This is because vaporization in the heat transfer tube of the economizer 40 can be further accelerated.

As described above, the bypass line (B) solves problems caused by the load of the boiler 10, operating conditions, or seasonal factors, and is for efficient operation of the boiler 10, in addition to the contents described in this specification. It can be implemented in various forms.

In addition, in FIGS. 1 to 4 , the unexplained reference numeral '100' denotes an on/off valve disposed on the first supply line L1 to control the supply of water from the water supply tank 20 to the first economizer 30 . (100).

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

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

L: water supply line
L1 ~ L3: 1st supply line ~ 3rd supply line
B1, B2: first bypass and second bypass
1: exhaust gas flue
10: boiler
20: water tank
30: first economizer
40: second economizer
50: air preheater
60: control valve
70: compartment
80: combustion air flow path
90: blow fan
100: on/off valve

Claims (7)

boiler (10);
a water supply tank 20 for supplying water to the boiler 10;
a first economizer 30 installed in the exhaust gas flue 1 to generate first heated water through heat exchange between the supply water supplied from the water supply tank 20 and exhaust heat;
A second economizer ( 40); and
an air preheater 50 disposed on one side of the first economizer 40 to receive combustion air and preheat the combustion air through heat exchange between the first heated water and the combustion air;
A boiler to increase exhaust heat recovery efficiency, including:
The method of claim 1,
The feed water supply line (L) circulating from the water supply tank 20 to the boiler 10 is
a first supply line (L1) leading from the water supply tank (20) to the first economizer (30);
a second supply line (L2) leading from the first economizer (30) and the air preheater (50) to the second economizer (40);
A boiler for increasing exhaust heat recovery efficiency, characterized in that it includes a third supply line (L3) leading from the second economizer (40) to the boiler (1).
3. The method of claim 2,
Exhaust heat recovery efficiency, characterized in that it further comprises a first bypass (B1) for bypassing the second heated water supplied to the boiler (10) through the third supply line (L3) to the water supply tank (20) Boiler to increase
4. The method of claim 3,
Exhaust heat further comprising a second bypass (B2) for diverting the second heated water supplied to the boiler (10) through the third supply line (L3) to the second supply line (L2) Boiler to increase recovery efficiency.
5. The method of claim 4,
On the third supply line (L3), the first bypass (B1) or the second bypass (B2), or the first and second bypass (B1) (B2), the second heating water is bypassed and controlled Boiler for increasing exhaust heat recovery efficiency, characterized in that the control valve (60) is further provided.
The method of claim 1,
The first economizer 40 and the air preheater 50 are provided with a partitioning part 70 for partitioning a section between each other,
The downstream side of the air preheater (50) is provided with a combustion air flow path (80) for guiding the combustion air introduced into and discharged from the air preheater (50) to the boiler (10) To increase exhaust heat recovery efficiency Boiler.
6. The method of claim 5,
The boiler for increasing exhaust heat recovery efficiency, characterized in that the heat transfer tubes of the first economizer (40) and the air preheater (50) are disposed to cross each other through the partition (70).

Images