WO2014079247A1

WO2014079247A1 - Power station boiler economizer

Info

Publication number: WO2014079247A1
Application number: PCT/CN2013/082334
Authority: WO
Inventors: 姚丹花
Original assignee: 上海锅炉厂有限公司
Priority date: 2012-11-20
Filing date: 2013-08-27
Publication date: 2014-05-30
Also published as: PL409129A1; CN102913896A; ZA201406662B; PL234394B1; MY186040A

Abstract

Disclosed is a power station boiler economizer, comprising a feed water pipeline (4), an inlet header box (1), a heat exchange surface (2), an outlet header box (3) and an outlet pipeline (8), wherein the feed water is heated when the flue gas flows through the outside of the heat exchange surface (2), a first bypass pipeline (5) is provided between the feed water pipeline (4) and the outlet pipeline (8) for connecting the two, and furthermore, the first bypass pipeline (5) is provided with a bypass temperature-regulation device (9).

Description

Power station boiler economizer

Technical field

The invention relates to a power plant boiler economizer. Background technique

The economizer is a heating surface that is arranged to heat the boiler feed water in the boiler flue of the power station. Because it absorbs relatively low temperature flue gas, it reduces the flue gas exhaust temperature, saves energy and improves efficiency, so it is called For the economizer.

Generally, the economizer can be divided into series arrangement, parallel arrangement or series and parallel system design according to different processes. Different system designs are applied to different boiler systems, that is, the flue gas temperature at the boiler outlet is lowered, and the heating is performed. Boiler feed water.

However, no matter which system is mentioned above, the heating surface called the economizer through which the feed water passes is arranged in the flue, and the heat from the flue gas side, that is, the heat of the medium in the economizer comes from the flue gas. .

However, the current economizer does not have the function of temperature adjustment. Summary of the invention

It is an object of the present invention to provide a power plant boiler economizer that can regulate the temperature of a fluid medium. In order to achieve the above object, the technical solution of the present invention is a power plant boiler economizer, comprising a water supply pipe, an inlet header, a heat exchange surface, an outlet header and an outlet pipe, and the flue gas flows through the feed water outside the heat exchange surface. Heating, a first bypass pipe connecting the two is provided between the water supply pipe and the outlet pipe, and the first bypass pipe is further provided with a bypass temperature regulating device. The invention realizes the function of reducing the temperature of the boiler outlet flue gas and increasing the feed water temperature while the original economizer system is being realized, and the temperature of the fluid medium passing through the container can be appropriately adjusted as needed to control the temperature within a certain range.

The water supply pipe passes through the three-way, two-way, one way to the first bypass pipe, one way is the main pipe to the heat exchange surface, and the main pipe or the bypass pipe is provided with a regulating valve.

The bypass temperature regulating device may be a heat exchange surface heated by the flue gas, and a related valve is also disposed on the main pipe or the bypass pipe.

The three-way is an electromagnetic reversing valve. The bypass temperature regulating device comprises a container, an inlet header, a heat exchange surface and an outlet header; the container flows through the temperature-regulated flue gas.

A temperature measuring and feedback device is arranged after the junction of the first bypass pipe and the outlet pipe for measuring the temperature of the steam and water, and a feedback device is arranged between the first bypass regulating valve and the temperature measuring device, and when the temperature is low At a certain temperature, the opening degree of the first bypass regulating valve becomes small.

A temperature measuring and feedback device is arranged at the outlet of the container for measuring the temperature of the flue gas, and a feedback device is arranged between the first bypass regulating valve and the temperature measuring device, and the first bypass is made when the temperature is lower than a certain temperature. The opening of the regulating valve becomes smaller.

A switching device is further included, the switching device comprising: a regulating valve on the first bypass, a regulating valve on the main pipe, a shut-off valve on the outlet pipe, a shut-off valve on the second bypass; a regulating valve on the main pipe, When the shut-off valve on the outlet pipe is opened, the regulating valve on the first bypass and the shut-off valve on the second bypass are closed, the economizer is arranged in reverse flow; when the regulating valve on the first bypass is closed on the second bypass When the valve is opened, the regulating valve on the main pipe and the shut-off valve on the outlet pipe are closed, the economizer flows downstream.

A temperature measuring device is arranged at the flue gas outlet of the economizer for measuring the temperature of the flue gas, and a feedback device is arranged between the switching device and the temperature measuring device, and the switching device is cocurrently when the temperature is lower than a certain temperature. Countercurrent switching. In the technical solution, the temperature of the economizer outlet flue gas can be changed by switching between the forward flow and the reverse flow. When the economizer is countercurrent, the heat transfer temperature is high, the heat absorption is large, and the flue gas temperature at the economizer outlet is low; when the economizer is downstream, the heat transfer temperature is low, the heat absorption is small, and the economizer outlet The temperature of the flue gas is high.

The economizer system according to the present invention improves the conventional system design, and enables the economizer to function to reduce the temperature of the boiler outlet flue gas and increase the feed water temperature, and at the same time has the function of temperature adjustment. DRAWINGS

Figure 1 is a schematic diagram of an economizer system;

Figure 2 is a schematic diagram of a bypass temperature adjustment device;

Figure 3 is a schematic diagram of downstream reverse current switching.

In the figure: Economizer inlet header 1, conventional economizer system (can be parallel, series or series-parallel type) 2, economizer outlet header 3, water supply pipeline 4, first bypass pipeline 5, main pipeline Regulating valve 6, first bypass regulating valve 7, economizer outlet pipe 8, bypass temperature regulating device 9, inlet header 10, heat exchange surface 11, outlet header 12, vessel (pipe or header) The outlet pipe shut-off valve 14 and the second bypass shut-off valve 15 are provided. detailed description

The present invention will be further described in detail below with reference to the drawings and specific embodiments, but the invention is not limited to the following examples.

The economizer system includes: an economizer inlet header, an economizer heating surface, an economizer outlet header, and an economizer outlet pipe. The water supply pipe is connected to the inlet of the economizer inlet header.

The area drawn by the dotted line in Fig. 1 is a conventional economizer system, which may be a combination of parallel, series or series-parallel connection. The area enclosed by the dotted line may not only be the economizer heating surface, but also the header and the pipeline.

The flow of the first bypass pipe 5 starts from the water supply pipe 4, and the flow returns to the economizer outlet pipe 8. The actual process is not limited thereto, and the route may be the water supply pipe 4 or the economizer inlet header 1 . At the end of the process, you can return to the economizer outlet pipe 8 or return to the economizer outlet header 3 .

The main pipe regulating valve 6 and the first bypass regulating valve 7 can be installed at the same time, or the system can be installed only. The advantage of the system is that the original economizer system can reduce the boiler outlet flue gas temperature and increase the feed water temperature. The temperature of the fluid medium passing through the container 13 can be appropriately adjusted as needed to be controlled within a certain range.

The temperature of the medium to be tempered in the bypass temperature regulating device 9 may be parallel to the medium in the heat exchange surface 11, or may be vertical, and may flow in the direction shown or may flow in the opposite direction to the direction shown.

The heated surface 11 is mounted in a container 13, which may be a pipe, a header or other device. Flowing in the container 13 is a medium that requires temperature adjustment.

How the system works:

In the case where temperature adjustment is not required, the first bypass regulating valve 7 is closed, no flow is passed through the first bypass duct, and the bypass temperature regulating device 9 is not operated, when the temperature regulating medium in the bypass temperature regulating device is There is a phenomenon of high temperature. When temperature adjustment is required, the bypass bypass temperature adjustment device can be operated by opening the first bypass regulating valve 7, and the temperature of the temperature-controlled medium is lowered, and the opening of the first bypass regulating valve 7 is The bigger the speed, the faster the cooling. Since the first bypass regulating valve 7 diverts the flow into the main pipe (i.e., into the economizer in the dotted line), the economizer outlet flue gas temperature also changes.

Bypass thermostat working principle:

When the temperature-regulating medium flowing through the container in the bypass temperature regulating device needs to be temperature-adjusted, that is, the temperature is too high, and the temperature needs to be lowered, the water in the first bypass pipe flows through the adjustment of the regulating valve (original In order to enter the medium of the economizer, the water passes through the heat exchange surface 11, and the water flows in the heat exchange surface 11 to cool the temperature-regulating medium outside the heat exchange surface 11 and in the vessel 13.

The flow rate of the water entering the heat exchange surface 11 can be adjusted by adjusting the opening degree of the valve to obtain an ideal cooling effect.

Figure 3 is a schematic diagram of downstream reverse current switching. Downstream and countercurrent refer to the relative flow direction between the working fluid (water vapor, feed water, air, etc.) and the flue gas. When the flow direction of the flue gas and the working fluid is the same, it is called the downstream flow; when the flow direction of the flue gas and the working fluid is opposite, it is called the countercurrent. As shown in FIG. 3, on the basis of FIG. 1, an outlet pipe shut-off valve 14 is disposed after the junction of the outlet header 3 and the first bypass pipe, and a second bypass pipe is drawn after the regulating valve 6, The second bypass line is connected to the outlet line 8 after the line valve 14, and the shut-off valve 15 is provided on the second bypass line.

Assume that the flue gas is flowing downward from the economizer outlet. When the flow is reversed, the regulating valve 6 and the shut-off valve 14 are opened, and the shut-off valve 15 is closed, and the working fluid flows in from the economizer inlet header 1 and flows out from the economizer outlet header, at which time the flow direction of the flue gas and the working fluid Instead, it is countercurrent. When flowing downstream, the regulating valve 6 and the shut-off valve 14 are closed, the regulating valve 7 and the shut-off valve 15 are opened, the working medium enters from the outlet header, and after heating in the heating surface 2, flows out from the inlet header, passes through the shut-off valve After 15 flows to the outlet pipe 8, when the flow direction of the flue gas and the working fluid is the same.

Therefore, switching between the forward and reverse flows is achieved by the switching of the four valves. When the total amount of steam and water medium entering the economizer is constant, the temperature of the flue gas at the economizer outlet can be changed by switching between downstream and countercurrent. When the economizer is countercurrent, the heat transfer temperature is high, the heat absorption is large, and the flue gas temperature at the economizer outlet is low; when the economizer is downstream, the heat transfer temperature is low, the heat absorption is small, and the economizer outlet The temperature of the flue gas is high.

Claims

Rights request:

1. A power plant boiler economizer comprising a water supply pipe (4), an inlet header (1), a heat exchange surface (2), an outlet header (3) and an outlet pipe (8), and the flue gas is on the heat exchange surface The external flow passes through the heating water, and is characterized in that: between the water supply pipe (4) and the outlet pipe (8), a first bypass pipe (5) connecting the two is provided, and the first bypass pipe (5) A bypass thermostat (9) is also provided.

2. The power plant boiler economizer according to claim 1, wherein:

The water supply pipe (4) passes through the three-way, two-way, one way to the first bypass pipe, one way is the main pipe to the heat exchange surface (2), and the main pipe is provided with a main pipe regulating valve (6) or A first bypass regulating valve (7) is disposed on the first bypass conduit (5).

3. The power plant boiler economizer according to claim 2, wherein:

The bypass temperature regulating device (9) may be a heat exchange surface heated by the flue gas.

4. The power plant boiler economizer according to claim 2, wherein:

The three-way is an electromagnetic reversing valve.

5. The power plant boiler economizer according to claim 3, wherein:

The bypass temperature regulating device (9) comprises a container (13), an inlet header (10), a heat exchange surface (11) and an outlet header (12); the container (13) flows through the temperature-regulated smoke gas.

6. The power plant boiler economizer according to claim 5, wherein:

a temperature measuring device is arranged after the junction of the first bypass pipe and the outlet pipe (8) for measuring the temperature of the steam and water, and a feedback device is arranged between the first bypass regulating valve (7) and the temperature measuring device, and When the temperature is lower than a certain temperature, the opening degree of the first bypass regulating valve (7) becomes small.

7. The power plant boiler economizer according to claim 5, wherein:

A temperature measuring device is disposed at the outlet of the container (13) for measuring the temperature of the flue gas, and a feedback device is disposed between the first bypass regulating valve (7) and the temperature measuring device, and when the temperature is lower than a certain temperature, The opening degree of the first bypass regulating valve (7) becomes small.

8. The power plant boiler economizer according to claim 2 or 3, characterized in that:

A switching device is also included, the switching device comprising: a regulating valve (7) on the first bypass, a regulating valve (6) on the main pipe, a shut-off valve (14) on the outlet pipe, and a shut-off on the second bypass Valve (15); when the regulating valve on the main pipe, the shut-off valve on the outlet pipe is opened, the regulating valve on the first bypass, and the shut-off valve on the second bypass are closed, the economizer is arranged in a reverse flow; When the regulating valve on the first bypass, the shut-off valve on the second bypass is opened, the regulating valve on the main pipe, and the shut-off valve on the outlet pipe are closed, the economizer is arranged downstream.

9. The power plant boiler economizer according to claim 8, wherein:

A temperature measuring device is arranged at the flue gas outlet of the economizer for measuring the temperature of the flue gas, and a feedback device is arranged between the switching device and the temperature measuring device, and the switching device is cocurrently when the temperature is lower than a certain temperature. Countercurrent switching.