KR20240067725A - Once-through evaporator of vertical heat recovery steam generator and heat recovery steam generator including the same - Google Patents

Abstract

The present invention relates to a once-through type evaporator of a vertical waste heat recovery boiler and a waste heat recovery boiler including the same. More specifically, a once-through type evaporator of a vertical waste heat recovery boiler in which the heat transfer tube has an inner diameter at the rear end larger than the inner diameter at the front end. and a waste heat recovery boiler including the same.
The once-through evaporator of the vertical waste heat recovery boiler according to the present invention and the waste heat recovery boiler including the same have heat transfer tubes with an inner diameter at the rear end larger than the inner diameter at the front end, thereby preventing static instability.

Description

Once-through evaporator of vertical heat recovery steam generator and heat recovery steam generator including the same}

The present invention relates to a once-through type evaporator of a vertical waste heat recovery boiler and a waste heat recovery boiler including the same. More specifically, a once-through type evaporator of a vertical waste heat recovery boiler in which the heat transfer tube has an inner diameter at the rear end larger than the inner diameter at the front end. and a waste heat recovery boiler including the same.

Combined cycle power generation is a power generation method that combines primary and secondary power generation facilities. In general, combined cycle power plants burn fuel inside a gas turbine to create high-temperature combustion gas, use this combustion gas to turn the gas turbine to generate primary power, and use the heat of the exhaust gas discharged during the primary power generation to produce high-temperature combustion gas. A steam turbine is driven by high-pressure steam to generate secondary power. This combined cycle power plant has high energy use efficiency by first using the combustion heat of the fuel in the gas turbine and reusing it in the heat recovery boiler, and has the advantage of shortening the time from starting operation to producing electricity. Additionally, it is environmentally friendly as it can use clean fuel.

The heat of the exhaust gas to produce high-temperature and high-pressure steam can be recovered by a heat recovery steam generator (HRSG), a type of heat exchange device.

Waste heat recovery boilers can be largely divided into horizontal and vertical types depending on the direction of exhaust gas flow. The horizontal method is a method in which the exhaust gas flows in a horizontal direction, and the vertical method is a method in which the exhaust gas flows in a vertical direction. The vertical method has the advantage of having a smaller installation area than the horizontal method.

In addition, waste heat recovery boilers can be largely divided into natural circulation and forced circulation types depending on the circulation method inside the boiler. The natural circulation method is a method in which the flow is formed by a density difference, and the forced circulation method is a method in which the circulation of water or steam inside the boiler is achieved by a separately provided circulation pump.

In the evaporator inside such forced circulation and vertical waste heat recovery boilers, static instability (or ledinegg instability) may occur due to two phase flow. Static instability occurs when a plurality of intersection points are formed between the pressure drop curve inside the evaporator and the pressure drop curve of the external head (pump, etc.) of the evaporator. This static instability can cause the problem that the actual mass flow rate inside the evaporator may differ from the pre-designed mass flow rate.

Based on the above technical background, the once-through evaporator of the vertical waste heat recovery boiler according to the present invention and the waste heat recovery boiler including the same can prevent static instability phenomenon.

The once-through type evaporator according to an embodiment of the present invention is a once-through type evaporator applied to a vertical waste heat recovery boiler, in which an inlet part through which water flows and a front end are connected to the inlet part, steam is discharged at the rear end, and the inlet part is connected to the inlet part. The water flowing in from the unit includes a heat transfer tube in which water is evaporated by exchanging heat with the main gas flow while flowing from the front end to the rear end, and the heat transfer tube has an inner diameter at the rear end larger than that at the front end.

Additionally, the inlet portion may be composed of a thin tubule whose inner diameter is smaller than the inner diameter of the heat transfer tube.

Additionally, the heat transfer tube includes a plurality of heat transfer units with different inner diameters, and the internal diameter of each heat transfer unit may gradually increase toward the rear end of the heat transfer tube.

In addition, the heat transfer tube includes a first heat transfer portion having a front end connected to the rear end of the inlet portion and a first inner diameter that is a larger inner diameter than the inner diameter of the inlet portion, and a first heat transfer portion whose front end is connected to the rear end of the first heat transfer section and an inner diameter that is larger than the first inner diameter. It may include a second heating unit having 2 inner diameters.

Additionally, heat transfer fins disposed on the main gas flow path may be disposed in the heat transfer tube.

Additionally, a greater number of heat transfer fins may be disposed on the rear end of the heat transfer pipe than on the front end of the heat transfer pipe.

Additionally, an orifice provided to control the pressure of incoming water may be disposed at the inlet portion.

Additionally, the inlet portion is composed of a thin tubule whose inner diameter is smaller than the inner diameter of the heat transfer tube, an inlet header is disposed at the front end of the tubule, and an orifice may be disposed at the inlet header.

A vertical waste heat recovery boiler according to an embodiment of the present invention includes a casing that forms the outer shape, a duct that connects the casing and a gas turbine, and supplies main gas from the gas turbine, and a once-through type evaporator placed inside the casing. , the evaporator is a heat transfer tube that has an inlet through which water flows, and the front end is connected to the inlet, steam is discharged at the rear end, and the water flowing in from the inlet exchanges heat with the main gas flow and evaporates while flowing from the front end to the rear end. It includes, and the heat transfer tube has an inner diameter at the rear end that is larger than the inner diameter at the front end.

Additionally, the inlet portion may be composed of a thin tubule whose inner diameter is smaller than the inner diameter of the heat transfer tube.

Additionally, the heat transfer tube includes a plurality of heat transfer units with different inner diameters, and the internal diameter of each heat transfer unit may gradually increase toward the rear end of the heat transfer tube.

In addition, the heat transfer tube includes a first heat transfer portion whose front end is connected to the rear end of the inlet section and has a first inner diameter that is a larger inner diameter than the inner diameter of the inlet section, and a first heat transfer section whose front end is connected to the rear end of the first heat transfer section and an inner diameter that is larger than the first inner diameter. It may include a second heating unit having an inner diameter of 2.

Additionally, heat transfer fins disposed on the main gas flow path may be disposed in the heat transfer tube.

Additionally, a greater number of heat transfer fins may be disposed on the rear end of the heat transfer pipe than on the front end of the heat transfer pipe.

Additionally, an orifice provided to adjust the pressure of incoming water may be disposed at the inlet portion.

Additionally, the inlet portion is composed of a thin tubule whose inner diameter is smaller than the inner diameter of the heat transfer tube, and an inlet header is disposed at the front end of the tubule, and an orifice may be disposed at the inlet header.

The once-through evaporator of the vertical waste heat recovery boiler according to the present invention and the waste heat recovery boiler including the same have heat transfer tubes with an inner diameter at the rear end larger than the inner diameter at the front end, thereby preventing static instability.

Figure 1 is a schematic diagram showing a part of a combined cycle power generation system to which the vertical waste heat recovery boiler according to the present invention is applied.
Figure 2 is a conceptual diagram showing a cut-away vertical waste heat recovery boiler according to the present invention.
Figure 3 is a conceptual diagram showing a cutaway view of the once-through type evaporator of a waste heat recovery boiler according to the first embodiment of the present invention.
Figure 4 is an enlarged cross-sectional view of the once-through evaporator of Figure 3.
Figure 5 is a conceptual diagram showing a cutaway view of the once-through type evaporator of a waste heat recovery boiler according to a modification of the first embodiment of the present invention.
Figure 6 is a graph showing the pressure drop characteristic curve of the waste heat recovery boiler according to the first embodiment of the present invention.
Figure 7 is a conceptual diagram showing the once-through evaporator of the waste heat recovery boiler according to the first embodiment of the present invention cut away and additional heat transfer fins disposed.
Figure 8 is a conceptual diagram showing an enlarged cutaway view of the once-through type evaporator of a waste heat recovery boiler according to the second embodiment of the present invention.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be exemplified and explained in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention.

The terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as 'include' or 'have' are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that it does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. At this time, note that in the attached drawings, like components are indicated by the same symbols whenever possible. Additionally, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some components are exaggerated, omitted, or schematically shown in the accompanying drawings.

Hereinafter, with reference to the attached drawings, a once-through evaporator of a vertical waste heat recovery boiler according to the present invention and a waste heat recovery boiler including the same will be described in detail.

Figure 1 is a schematic diagram showing a part of a combined cycle power generation system to which the vertical waste heat recovery boiler according to the present invention is applied. Figure 2 is a conceptual diagram showing a cut-away vertical waste heat recovery boiler according to the present invention.

Hereinafter, with reference to FIG. 1, the overall process of the combined cycle power generation cycle to which the waste heat recovery boiler 1000 according to an embodiment of the present invention is applied will be described in detail. The combined cycle power generation cycle includes a gas turbine (100), a steam turbine (200), a condenser (300), a circulation pump (400), and a waste heat recovery boiler (1000).

In the gas turbine 100, fuel and air are mixed and then combusted to generate high-temperature combustion gas, and the power generated by the high-temperature combustion gas drives a generator connected to the gas turbine 100. High-temperature, high-pressure steam is supplied to the steam turbine 200. High-temperature, high-pressure steam supplied to the steam turbine 200 provides driving force to a generator connected to the steam turbine 200, thereby driving the generator. In the steam turbine 200, steam provides power to drive a generator and is then supplied to the condenser 300. In the condenser 300, the vapor is cooled and converted into condensate. In the condenser 300, the vapor may be cooled by a cooling means such as externally supplied cooling water and converted into condensate.

A waste heat recovery boiler 1000 is disposed between the gas turbine 100 and the steam turbine 200. Exhaust gas, which is combustion gas discharged from the gas turbine 100, is supplied to the waste heat recovery boiler 1000, and water, which is condensate or feed water supplied from the condenser 300, is supplied. The water supplied to the condenser 300 may be provided with a flow force by the circulation pump 400. The circulation pump 400 may be disposed between the condenser 300 and the waste heat recovery boiler 1000.

In the waste heat recovery boiler 1000, exhaust gas and water exchange heat with each other. The water supplied to the waste heat recovery boiler (1000) is heated by hot exhaust gas and evaporated into steam. The steam generated by evaporation in the waste heat recovery boiler (1000) is supplied to the steam turbine (200). Here, the steam generated in the waste heat recovery boiler 1000 may be superheated by additionally passing through a superheater before being supplied to the steam turbine 200. So, the flow of exhaust gas discharged from the gas turbine 100 is called main gas flow (MF).

Hereinafter, with reference to FIG. 2, a waste heat recovery boiler 1000 according to an embodiment of the present invention will be described in detail. The waste heat recovery boiler 1000 according to an embodiment of the present invention is a vertical waste heat recovery boiler 1000. The vertical waste heat recovery boiler 1000 is a waste heat recovery boiler 1000 in which the flow direction of the main gas flow (MF) is vertical. A waste heat recovery boiler 1000 according to an embodiment of the present invention includes a casing 1100 and an evaporator 1200.

The casing 1100 forms the external shape of the waste heat recovery boiler 1000. The casing 1100 may be formed to extend long in the vertical direction. A duct 1110 connecting the casing 1100 and the gas turbine 100 may be disposed on the lower side of the casing 1100. The main gas flow (MF) of the gas turbine 100 is supplied through the duct 1110, and the cross-sectional area of the duct 1110 may be expanded along the flow direction of the main gas flow (MF). In the duct 1110, the main gas flow (MF) may flow in the horizontal direction and then switch to the vertical direction. Meanwhile, a stack 1120 through which the main gas flow (MF) is discharged may be disposed on the upper side of the casing 1100.

An evaporator 1200 is disposed inside the casing 1100. In the evaporator 1200, water may flow in and the water may be evaporated and discharged as steam. Water may flow into the inlet header 1210 of the evaporator 1200. The evaporated vapor may be discharged from the outlet header 1220 of the evaporator 1200. The evaporator 1200 may be formed in a zigzag-shaped piping structure that is bent a plurality of times, and each pipe may be formed to extend in the horizontal direction except for the bent portion. That is, the evaporator 1200 may be a once-through type evaporator 1200 formed horizontally.

The main gas flow (MF) passes through the evaporator 1200 disposed inside the casing 1100. As the main gas flow (MF) passes through the evaporator 1200, it exchanges heat with the water flowing inside the evaporator 1200, and in this process, the water flowing inside the evaporator 1200 is phase converted into steam. .

A circulation pump 400 may be disposed between the inlet header 1210 of the evaporator 1200 and the condenser 300, and the circulation pump 400 transfers water provided from the condenser 300 to the inlet header of the evaporator 1200. It can be supplied at (1210). Steam discharged from the outlet header 1220 of the evaporator 1200 may be supplied to the steam turbine 200. Alternatively, the steam discharged from the outlet header 1220 of the evaporator 1200 may be supplied to the steam turbine 200 after passing through a superheater before being supplied to the steam turbine 200.

Figure 3 is a conceptual diagram showing the once-through type evaporator of the waste heat recovery boiler according to the first embodiment of the present invention cut away, Figure 4 is an enlarged cross-sectional view showing the once-through type evaporator of Figure 3, and Figure 5 is the first embodiment of the present invention. It is a conceptual diagram showing a cut-through type evaporator of a waste heat recovery boiler according to a modification of the embodiment, and Figure 6 is a graph showing the pressure drop characteristic curve of the waste heat recovery boiler according to the first embodiment of the present invention.

Hereinafter, with reference to FIGS. 3 and 4, the once-through evaporator 1200 and the waste heat recovery boiler 1000 including the same according to the first embodiment of the present invention will be described in detail. The once-through evaporator 1200 according to the first embodiment of the present invention includes an inlet 1300 and a heat transfer tube 1400, and the inlet 1300 includes a tubule 1310.

The inlet 1300 is a pipe through which water flows from the evaporator 1200. Water supplied from the condenser 300 may flow into the inlet 1300. An entrance header 1210 may be placed at the entrance of the entrance unit 1300. The tubule 1310 is a thin pipe, and its inner diameter may be formed as the inlet inner diameter (DI). As the tubule 1310 is disposed, the pressure characteristic curve of the evaporator 1200 changes, and flow instability inside the evaporator 1200 can be improved.

The heat transfer pipe 1400 is a pipe whose front end is connected to the rear end of the inlet part 1300, and steam is discharged from the rear end. An outlet header 1220 may be disposed at the rear end of the heat pipe 1400. Water introduced from the inlet 1300 is supplied to the front end of the heat transfer pipe 1400, and while the water flows to the rear end of the heat transfer pipe 1400, it exchanges heat with the main gas flow MF and is evaporated before being discharged. The heat transfer tube 1400 has an inner diameter at the rear end that is larger than the inner diameter at the front end.

Additionally, the inlet inner diameter (DI), which is the inner diameter of the tubule 1310, may be smaller than the inner diameter of the heat transfer tube 1400. That is, in the evaporator 1200, the inlet inner diameter (DI) of the tubule 1310 of the inlet 1300 is smaller than the inner diameter of the front end of the heat transfer tube 1400, and the inner diameter of the front end of the heat transfer tube 1400 is smaller than the inner diameter of the front end of the heat transfer tube 1400. It may be formed smaller than the inner diameter of the rear end of.

The heat pipe 1400 may include a plurality of heat transfer units with different inner diameters, and the internal diameters of each heat transfer unit may be formed to gradually increase from the front end to the rear end of the heat transfer tube 1400. The heat pipe 1400 may include a first heat transfer unit 1410 and a second heat transfer unit 1420.

The first heat transfer unit 1410 is a heat transfer tube 1400 whose front end is connected to the rear end of the inlet unit 1300 and has an internal diameter of the first internal diameter D1. The first inner diameter D1 is formed to be larger than the inlet inner diameter DI. The second heat transfer unit 1420 is a heat transfer tube 1400 whose front end is connected to the rear end of the first heat transfer unit 1410 and has an inner diameter of the second inner diameter D2. The second inner diameter D2 is formed to be larger than the first inner diameter D1. That is, the inner diameter may increase in sequential steps from the evaporator 1200 to the inlet 1300, the first heat transfer unit 1410, and the second heat transfer unit 1420.

A tapered portion 1500 may be disposed between the tubule 1310 and the first heating unit 1410 and between the first heating unit 1410 and the second heating unit 1420, respectively. Specifically, a first tapered portion 1510 is disposed between the tubule 1310 and the first heating portion 1410, and a second tapered portion is disposed between the first heating portion 1410 and the second heating portion 1420. Unit 1520 may be disposed. In the tapered portion 1500, the inner diameter gradually increases toward the rear end. As the tapered portion 1500 is disposed, the inner diameter can be prevented from discontinuously increasing, thereby preventing flow separation and improving flow stability. Meanwhile, the tapered portion 1500 may have a straight cross-section or a rounded curved surface.

In addition, as shown in FIG. 5, the heat transfer pipe 1400 may further include a third heat transfer unit 1430. The third heat transfer unit 1430 is a heat transfer tube 1400 whose front end is connected to the rear end of the second heat transfer unit 1420 and has a third inner diameter D3. The third inner diameter (D3) is formed to be larger than the second inner diameter (D2). In this case, the inner diameter may increase in sequential steps from the evaporator 1200 to the inlet 1300, the first heat transfer unit 1410, the second heat transfer unit 1420, and the third heat transfer unit 1430. In addition, the heat pipe 1400 may be composed not only of two to three heat transfer parts as above, but may also be composed of four or more heat transfer parts whose inner diameter gradually increases toward the rear end.

Hereinafter, with reference to FIG. 6, the flow stability of the once-through type evaporator 1200 according to the first embodiment of the present invention will be described in detail.

A pressure difference occurs between the flow at the front end and the flow at the rear end of the evaporator 1200, and this pressure difference is called a system pressure drop. The system pressure drop varies depending on the mass flow rate of the flow. Since water evaporates inside the evaporator 1200, a two phase flow phenomenon occurs in which water and steam flow together. The change in pressure drop of gaseous vapor is larger than the change in pressure drop of liquid water. Accordingly, the system pressure drop curve (a curve with mass velocity on the horizontal axis and pressure drop on the vertical axis) of the evaporator 1200 in a two-phase flow state had a positive slope, then changed to a negative value, and then returned to a positive value. It is formed in a shape with ridges and valleys that change into (see thin solid line in Figure 6).

Meanwhile, the flow rate inside the evaporator 1200 is determined by the pressure drop curve of the external head of the evaporator. Here, the external head is a head that provides driving force, and may be determined by the height difference between the inlet header 1210 and the outlet header 1220 or the circulation pump 400 (see Figure 6). (see dotted line A). More specifically, the flow rate inside the evaporator 1200 is determined at the intersection between the system pressure drop curve and the pressure drop curve of the external head. In a two-phase flow state, as shown in FIG. 6, three intersections may be formed: 1, 2, and 3. In this case, the flow rate inside the evaporator 1200 may be determined at any one of the intersection points 1 to 3. If a plurality of evaporators 1200 are arranged in parallel, the flow rate inside the evaporators 1200 may not be determined by any one, but any one of the intersection points 1 to 3 may be arbitrarily determined. Accordingly, a mass flow rate different from the initial design flow rate (intersection point 1) can flow inside the evaporator 1200. This instability of the flow is called static instability (or ledinegg instability). If the flow rate is less than the initial design flow rate, a problem may occur in that the steam may be excessively overheated at the rear of the evaporator 1200.

In the evaporator 1200 according to the first embodiment of the present invention, since the heat transfer pipe 1400 is formed with an inner diameter at the rear end larger than the inner diameter at the front end, the system pressure drop curve can be formed more gently (the thick line in FIG. 6 (see solid line). In this case, only one intersection point (intersection point 1) is formed between the system pressure drop curve and the pressure drop curve of the external head, and static instability phenomenon can be prevented. In addition, as the inlet portion 1300 includes the tubule 1310, the system pressure drop curve is formed more gently, and static instability phenomenon can be more reliably prevented.

Figure 7 is a conceptual diagram showing the once-through evaporator of the waste heat recovery boiler according to the first embodiment of the present invention cut away and additional heat transfer fins disposed.

Hereinafter, with reference to FIG. 7, the structure in which heat conduction fins are additionally disposed in the once-through type evaporator 1200 according to the first embodiment of the present invention will be described in detail. Heat conduction fins 1600 may be additionally disposed in the once-through type evaporator 1200 according to the first embodiment of the present invention, and as the heat conduction fins 1600 are disposed, the internal flow of the evaporator 1200 and the main gas flow The heat transfer efficiency of heat exchange between (MF) can be increased.

The heating fins 1600 may be arranged differently depending on the area of the evaporator 1200. Specifically, the area of the inlet 1300 is the first area A1, the area of the first heat transfer unit 1410 is the second area A2, and the area of the second heat transfer unit 1420 is the third area. When (A3), the heating fins 1600 may be arranged differently in the first area (A1), the second area (A2), and the third area (A3).

For example, the first area (A1) is the 1-1 area (A1-1), which is the area downstream of the main gas flow (MF), and the 1-2 area (A1-), which is the area upstream of the main gas flow (MF). 2), and the heating fins 1600 may be disposed in the first area (A1), the second area (A2), and the third area (A3) excluding the 1-1 area (A1-1). This is because the 1-1 area (A1-1) is an area where the temperature of the main gas flow (MF) is relatively low, so the arrangement of the heat conduction fins 1600 may not be necessary.

Additionally, the number of heating fins 1600 may increase as it moves from the first area (A1) to the third area (A3). That is, a greater number of heat conduction fins 1600 may be disposed toward the first heat conduction portion 1410 and the second heat conduction portion 1420 than from the inlet portion 1300 side. Since the temperature of the main gas flow (MF) becomes relatively higher toward the upstream side, when the heat transfer fins 1600 are arranged in this way, the heat transfer efficiency of the evaporator 1200 can be increased.

Figure 8 is a conceptual diagram showing an enlarged cutaway view of the once-through type evaporator of the waste heat recovery boiler according to the second embodiment of the present invention.

Hereinafter, with reference to FIG. 8, the once-through evaporator 1200 and the waste heat recovery boiler 1000 including the same according to the second embodiment of the present invention will be described in detail. The once-through type evaporator 1200 according to the second embodiment of the present invention is different from the first embodiment in the inlet portion 1300. Hereinafter, for convenience of explanation, descriptions that overlap with those of the waste heat recovery boiler 1000 according to the first embodiment of the present invention will be omitted.

The once-through evaporator 1200 according to the second embodiment of the present invention has an orifice 1320 disposed at the inlet 1300. The orifice 1320 may be provided to adjust the pressure of incoming water. Accordingly, the system pressure drop curve of the evaporator 1200 is gently modified, and static instability phenomenon can be effectively prevented. The orifice 1320 may be disposed on the inlet header 1210 side of the inlet portion 1300. In FIG. 8, the orifice 1320 is shown as being disposed on the rear side of the inlet header 1210, but it may be disposed on the front side of the inlet header 1210 or inside the inlet header 1210.

The inlet 1300 may include both a tubule 1310 and an orifice 1320. In this case, the orifice 1320 may be disposed at the front portion of the tubule 1310. When the tubule 1310 and the orifice 1320 are arranged together, the system pressure drop curve of the evaporator 1200 is more gently modified, and static instability phenomenon can be more effectively prevented.

Although embodiments of the present invention have been described above, this is merely an example and the present invention is not limited thereto, and should be construed as having the widest scope following the basic ideas disclosed in this specification. A person skilled in the art may combine and substitute the disclosed embodiments to implement embodiments not specified, but this also does not deviate from the scope of the present invention. In addition, a person skilled in the art can easily change or modify the embodiments disclosed based on the present specification, and it is clear that such changes or modifications also fall within the scope of the present invention.

100: gas turbine
200: Steam turbine
300: condenser
400: Circulation pump
1000: Waste heat recovery boiler
1100: Casing
1110: duct
1120: stack
1200: Evaporator
1210: Entrance header
1220: Exit header
1300: entrance part
1310: Customs
1320: Orifice
1400: Heat pipe
1410: 1st electric heating unit
1420: 2nd electric heating unit
1430: 3rd electric unit
1500: Taper part
1510: 1st tapered part
1520: 2nd tapered part
1600: Electric heating fin
A1: Area 1
A1-1: Area 1-1
A1-2: Area 1-2
A2: Area 2
A3: Area 3
D1: 1st inner diameter
D2: 2nd inner diameter
D3: Third inner diameter
DI: Inlet inner diameter
MF: Main gas flow

Claims (16)

In a once-through evaporator applied to a vertical waste heat recovery boiler,
An inlet through which water flows; and
The front end is connected to the inlet, steam is discharged at the rear end, and water flowing in from the inlet part includes a heat transfer tube in which water is evaporated by exchanging heat with the main gas flow while flowing from the front end to the rear end,
The heat pipe is,
A once-through type evaporator wherein the inner diameter of the rear end is formed to be larger than the inner diameter of the front end.
According to claim 1,
The entrance part is,
A once-through type evaporator composed of a thin tubule whose inner diameter is smaller than the inner diameter of the heat transfer tube.
According to claim 1,
The heat pipe is,
It includes a plurality of heating parts with different inner diameters,
A once-through type evaporator in which the inner diameter of each heat transfer unit gradually increases toward the rear end of the heat transfer tube.
According to clause 3,
The heat pipe is,
a first heat transfer portion whose front end is connected to the rear end of the inlet portion and has a first inner diameter that is larger than the inner diameter of the inlet portion; and
A once-through type evaporator, the front end of which is connected to the rear end of the first heat transfer unit, and a second heat transfer unit having a second internal diameter that is larger than the first internal diameter.
According to claim 1,
In the heat pipe,
A once-through type evaporator in which heating fins are placed on the main gas flow path.
According to clause 5,
The heating fin is,
In the heat transfer tube, a once-through type evaporator is disposed in a larger number on the rear end side of the heat transfer tube than on the front end side.
According to claim 1,
At the entrance,
A once-through type evaporator in which an orifice is provided to regulate the pressure of incoming water.
According to clause 7,
The entrance part is,
It is composed of a thin tubule whose inner diameter is smaller than the inner diameter of the heat transfer tube,
An entrance header is placed at the front of the customs office,
A once-through type evaporator wherein the orifice is disposed at the inlet header.
Casing forming the outline;
A duct connecting the casing and a gas turbine and supplying main gas from the gas turbine; and
It includes a once-through type evaporator placed inside the casing,
The evaporator,
An inlet through which water flows; and
The front end is connected to the inlet, steam is discharged at the rear end, and water flowing in from the inlet part includes a heat transfer tube in which water is evaporated by exchanging heat with the main gas flow while flowing from the front end to the rear end,
The heat pipe is,
A vertical waste heat recovery boiler in which the inner diameter of the rear end is larger than the inner diameter of the front end.
According to clause 9,
The entrance part is,
A vertical waste heat recovery boiler composed of thin tubing whose inner diameter is smaller than the inner diameter of the heat transfer tube.
According to clause 9,
The heat pipe is,
It includes a plurality of heating parts with different inner diameters,
A vertical waste heat recovery boiler in which the inner diameter of each heat transfer unit gradually increases toward the rear end of the heat transfer tube.
According to claim 11,
The heat pipe is,
A first heat transfer portion whose front end is connected to the rear end of the inlet portion and has a first inner diameter that is larger than the inner diameter of the inlet portion; and
A vertical waste heat recovery boiler having a front end connected to a rear end of the first heat transfer unit and a second heat transfer unit having a second internal diameter that is larger than the first internal diameter.
According to clause 9,
In the heat pipe,
A vertical waste heat recovery boiler with heat transfer fins placed on the main gas flow path.
According to claim 13,
The heating fin is,
In the heat transfer tube, a vertical waste heat recovery boiler is disposed more on the rear end side of the heat transfer tube than on the front end side.
According to clause 9,
At the entrance,
A vertical waste heat recovery boiler equipped with an orifice to control the pressure of incoming water.
According to claim 15,
The entrance part is,
It is composed of a thin tubule whose inner diameter is smaller than the inner diameter of the heat transfer tube,
An entrance header is placed at the front of the customs office,
The orifice is a vertical waste heat recovery boiler disposed at the inlet header.

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