JPS5836243B2 - steam generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steam generator, and particularly to a steam generator that uses exhaust heat from other equipment as a heat source.

Generally, a steam generator is equipped with an economizer section, an evaporator section, and a superheating section. The water is evaporated into the evaporation section and turned into a steam-water mixture, which is then led to the steam-water drum again.The saturated steam from the steam-water drum is superheated in the superheating section to become superheated steam, and then the superheated steam is It is guided by a turbine etc.

However, if the heat source of the steam generator cannot be maintained at a constant temperature, for example if the heat source of the steam generator is exhaust gas from other industrial equipment, the temperature of the exhaust gas will be the same as that of the industrial equipment. When the exhaust gas temperature changes depending on the operating situation and the temperature of the exhaust gas is low, the steam flow rate automatically decreases due to the design to maintain a constant water level in the steam drum. Evaporation begins, causing system vibrations and other problems in the steam generator.

This invention was made in view of the above circumstances, and it is an object of the present invention to appropriately adjust the amount of heat received by the water supplied to the economizer section and the evaporator section of the steam generator even when the temperature of the heat source changes. The object of the present invention is to provide a steam generator in which system vibration and other troubles can be reliably avoided.

Corresponding to this purpose, the steam generator of the invention has at least an economizer section, an evaporator section, a superheating section and an air-water drum, the heat transfer tubes of the economizer section and the transfer tubes of the evaporator section. Connect the heat pipes with piping equipped with valves, and provide valves between the heat transfer tubes and the drum in the economizer section and between the heat transfer tubes and the drum in the evaporation section.By opening and closing each valve, the economizer The present invention is characterized in that the effective length of the heat exchanger tubes in each section and the effective length of the heat exchanger tubes in the evaporation section are adjusted.

The details of this invention will be explained below with reference to the drawings showing one embodiment.

In FIG. 1, 1 is a steam generator, and the steam generator 1
comprises a flue 2 with a hot gas inlet 3 and a hot gas outlet 4.

Inside the flue 2, there are a plurality of stages of heat exchanger tubes 6 that surround the economizer section 5, a plurality of stages of heat exchanger tubes 8 that surround the evaporator section 7, and a plurality of stages of heat exchanger tubes that surround the superheater section 9. 11 is located.

The economizer section is equipped with multiple stages of heat exchanger tubes, and at least some of the heat exchanger tubes near the final stage, including the final stage, are connected to the drum through valves, and are connected to the adjacent downstream heat exchanger tubes through other valves. It is configured to be connected to.

That is, in this embodiment, the 10th stage heat exchanger tube 6a and the 12th stage heat exchanger tube 6c in the economizer section 5 are in communication with each other through the pipes 12 and 13 facing outside the flue 2, and the pipe 12 and 13 are connected to the drum 15 by piping 14.
has reached.

Pipes 12 and 13 are provided with valves b and e, respectively.

The spun 11th stage heat transfer tube 6b is connected to the inlet pipe 17 which communicates with the first stage heat transfer tube 8a of the evaporation section 7 via a pipe 16, and the inlet pipe 17 is connected to the drum 15 via a pump 18. It communicates with

A valve C is provided in the pipe 16.

The 10th stage heat exchanger tube 6a and the 11th stage heat exchanger tube 6b in the economizer section 5 are pipes 19 equipped with a valve d.
Furthermore, the 12th stage heat transfer tube 6c in the economizer section 5 and the first stage heat transfer tube 8a toward the evaporation section 7 are connected via a pipe 21 equipped with a valve a. There is.

A valve f is provided between the connection between the pipes 16 and 17 and the connection between the pipes 17 and 21.

According to the specifications of the steam generator 1 configured in this way, during normal operation, valves b, d, and f are open, and valves a, c, and e are closed, as shown in Figure 2. All heat exchanger tubes 6 including heat exchanger tubes 6a, 6b, 6c destined for economizer section 5
is used as a heat transfer tube to bring the feed water to the saturation temperature.

The steam flow rate in this case is 00.7 t/h as described above, and evaporation starts at the inlet of the evaporation section 7, as shown in FIG.

1. If the temperature of the exhaust gas, which is the heat source, becomes lower than a predetermined value, the steam flow rate will automatically be reduced to 73.5 mm due to the design to keep the water level of the air-water drum constant. Ot/
As mentioned above, as a result of the decrease in the temperature to h, as shown in FIG. 3, steam starts to flow before the exit of the economizer section 5, causing various troubles.

Therefore, in this case, as shown in FIG.
The second stage heat exchanger tubes 6b and 6c are connected to the steam section 7 side.

As a result, as shown in Fig. 5, economizer section 5 is composed of 10 stages of heat transfer tubes, and the steam flow rate is 65.
．． 5t/h, and no evaporation of the feed water occurs there.

As is clear from the above explanation, according to the present invention, the effective length of the heat transfer tubes in the economizer section and the evaporator section can be adjusted by simply opening and closing the valve, and the amount of heat received in each section can be adjusted appropriately. It is possible to avoid system vibration and other troubles.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the configuration of a steam generator according to an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the opening and closing states of the valves during normal operation, and Fig. 3 is an explanatory diagram showing the temperature of the feed water and the exchange heat flow rate. A graph showing the relationship, FIG. 4 is an explanatory diagram showing another example of the opening/closing state of the valve, and FIG. 5 is a graph showing the relationship between the warm eaves of the feed water and the exchange heat flow rate when the number of stages of the economizer section is changed. and FIG. 6 are graphs showing the relationship between the temperature of the feed water and the exchange heat flow rate during normal operation. 1... Steam generator, 5... Economizer section, 6... Heat transfer tube, 7... Evaporation section, 8... Transfer Heat tube, 9... Superheating section, 11... Heat exchanger tube, a, b, c, d, e...
···valve.

Claims (1)

[Claims] 1 At least an economizer section having a plurality of stages of heat transfer tubes, an evaporation section, a superheating section, and an air/water drum, and a space between the heat transfer tubes of the economizer section and the heat transfer tube of the evaporation section. A valve is provided between the heat transfer tube of the economizer section and the drum, and between a heat transfer tube of the evaporation section and the drum, and a plurality of stages near the final stage of the economizer section are connected. The heat exchanger tubes of at least some of the stages are connected to the drum through valves, and are connected to the adjacent heat exchanger tubes of subsequent stages through the valves, and the economizer section is controlled by opening and closing the respective valves. By adjusting the effective length of the heat exchanger tubes for the evaporation section and the effective length of the heat exchanger tubes for the evaporation section, a part of the heat exchanger tubes for the economizer section can be used as heat exchanger tubes for the evaporation section. A steam generator characterized by: