JPH1122913A - Drain recovering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the mixing of gas in drain into boiler feed water and prevent the mixing of rust in a steam pipeline into boiler feed water by a method wherein a drain recovery line is connected to a feed water tank and a gas separator, separating gas in the drain, is provided. SOLUTION: A make-up water line 6, a feed water line 7 and a drain recovery line 2 are connected to a feed water tank 1. A gas separator 3, separating gas in drain, is provided in the feed water tank 1 while the drain recovery line 2 is connected to the gas separator 3. In the gas separator 3, the water part in the feed water tank 1 communicates with a drain reserving tank 14 through a communicating pipe 15 while drain is reserved to the upper end position of the communicating pipe 15 and the drain, exceeding the upper end position of the same, drops into the water part in the feed water tank 1 after overflowing the upper end of the communicating pipe 15. Further, an initial drain discharging means 5 is connected to the drain reserving tank 14 to discharge the drain, recovered within a predetermined period of time after starting a boiler 4, to the outside of the feed water tank 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a drain recovery device for a boiler.

[0002]

2. Description of the Related Art Drain (condensed water) from equipment using steam
Is returned to the water supply tank and supplied to the boiler again. At that time, oxygen and carbon dioxide remaining in the steam pipe may enter the drain, and when the drain containing these gases returns to the water supply tank, the gas dissolves in the water in the water supply tank. Then, the water is supplied to the boiler together with water, which causes corrosion of the can body. Also, rust in the steam pipes may be mixed into the drain, and when the drain containing the rust returns to the water supply tank, the rust is supplied to the boiler and rust accumulates in the boiler, or rust is transferred to the water supply pump. Problems such as inflow and locking of the impeller occur.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent gas in a drain from being mixed into boiler feedwater and to prevent rust in steam piping from being mixed into boiler feedwater. .

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a structure in which a drain recovery line is connected to a water supply tank and a gas separator for separating gas in the drain is provided. The first feature is that the gas separator is provided in the water supply tank, and the second feature is that the gas separator is provided with an initial drain discharge means for discharging drain collected within a predetermined time after the boiler is started. This is the third feature.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A water supply tank for storing water to be supplied to a boiler is provided, and a drain recovery line is connected to the water supply tank. This drain recovery line serves to recover the steam generated in the boiler, which has been deprived of heat in the steam-using equipment and has become condensed water, again in the water supply tank. The water supply tank or the drain recovery line is provided with a gas separator for separating gas (such as oxygen and carbon dioxide) in the drain. This gas separator heats and degass the gas by the heat of the drain. Further, the gas separator may have a structure in which drain is passed through a gas permeable membrane or sprayed into a vacuum atmosphere to perform vacuum degassing. The removed gas is discharged outside the water supply tank. As water to be supplied to the water supply tank, degassed water from which dissolved gas has been removed is used to prevent gas from entering the water supply tank. The gas separator can be provided outside or inside the water supply tank. When provided inside, the entire drain recovery device can be made compact and the piping work can be simplified.

There is provided an initial drain discharging means for discharging the drain collected within a predetermined time after the boiler is started up to the outside. This initial drain discharge means connects a drain discharge line to a drain recovery line or a gas separator, provides an electric valve in this drain discharge line, opens this electric valve in response to a signal indicating that the boiler has started, and opens a timer. Is configured to be controlled to close upon receipt of a signal indicating that a predetermined time has passed since the start. A signal indicating that the boiler has started can be received directly from the boiler, or can be determined and output based on the pressure or temperature in the steam header where steam from a plurality of boilers is collected. By discharging the initial drain, it is possible to reliably discharge the rust that easily mixes into the initial drain to the outside without mixing it into the water supply tank.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. The makeup water line 6, the water supply line 7, and the drain recovery line 2 are connected to the water supply tank 1. The makeup water line 6 is provided with a ball tap mechanism 8 to supply makeup water to the makeup water tank 1 when the water level in the makeup water tank 1 decreases, and to stop the makeup water when the water level rises to a predetermined water level. ing. The distal end opening 9 of the makeup water line 6 is disposed submerged at a relatively lower position in the water supply tank 1. The makeup water is designed to supply degassed water from which dissolved gases (air, especially oxygen) have been removed,
By submerging the leading end opening 9 of the makeup water line 6, entrainment of air when makeup water flows into the water supply tank 1 is prevented. In the water supply tank 1, beads (not shown) are floated on the water surface to prevent re-dissolution of the air by preventing the beads from coming into contact with the air.

The water supply line 7 supplies the water in the water supply tank 1 to the boiler 4, and is provided with a water supply pump (not shown) on the way. The water supplied to the boiler 4 is heated and becomes steam, and is sent to the steam-using device 11 by the steam line 10. Steam header 1 in steam line 10
2, steam from a plurality of boilers 4 (only one is shown and others are omitted) is collected in the steam header 12, and heads to the steam-using device 11. The steam deprived of heat by the steam-using device partially becomes drain (condensed water), and the drain flows into the water supply tank 1 from the drain recovery line 2 via the steam trap 13.

In the water supply tank 1, a gas separator 3 for separating gas (such as oxygen and carbon dioxide) in the drain is provided, and a drain recovery line 2 is connected to the gas separator 3. By providing the gas separator 3 in the water supply tank 1, the entire drain recovery device can be made compact, and the piping work can be simplified. Gas separator 3
Is a drain storage tank 14 and the drain storage tank 1
4 is provided with a communication pipe 15 standing upright through the bottom portion.
The communication pipe 15 communicates the water in the water supply tank 1 with the inside of the drain storage tank 14, and the drain is stored up to the upper end position of the communication pipe 15. It is configured to drop into a water portion in the water supply tank 1. The tip opening 16 of the drain recovery line 2 is submerged in the drain stored in the drain storage tank 14.

Since the drain just collected is still in a high temperature state, gas is heated and degassed in the drain storage tank 14 by the retained heat of the drain. Drain storage tank 14
An opening 17 is provided at the upper end of the water supply tank 1, and the removed gas is discharged to the outside through an opening 17 provided at the top of the water supply tank 1 through the opening 17. The air in the gas separator 3 at the start of the drain recovery is also pushed out from the opening 17 by the steam generated from the drain, and is discharged to the outside through the atmosphere release hole 18.

A partition plate 19 is provided at an upper portion in the water supply tank 1, and an opening 20 is formed between a lower end of the partition plate 19 and a water surface. The partition plate 19 functions to prevent air entering through the air release hole 18 during drain recovery from entering the gas separator 3. The air has a lower temperature than the steam generated from the drain and accumulates below, so that the air does not flow into the gas separator 3 from the opening 17. Further, as described above, beads (not shown) float on the water surface in the water supply tank 1 so as to prevent contact with air so that the air does not redissolve.

An initial drain discharge means 5 is connected to the drain storage tank 14 so that drain collected within a predetermined time after the boiler 4 is started is discharged to the outside of the water supply tank 1. Specifically, a drain discharge line 21 is connected to a lower portion of the drain storage tank 14 and the drain discharge line 2
1 is provided with a motor-operated valve 22, and the opening and closing of the motor-operated valve 22 is controlled by a controller 23. In response to a signal from the pressure detector 24 provided in the steam header 12, it is determined that the boiler 4 has started based on a rise in the pressure in the steam header 12, and the motor-operated valve 22 is activated by a signal indicating that the boiler 4 has started. The motor-operated valve 22 is closed after a predetermined time has elapsed. Steam line 1
Since the rust in the drain line 0 and the drain recovery line 2 easily mixes into the initial drain, the initial drain containing the rust is discharged to the outside of the water supply tank 1 by the above-described initial drain discharge means 5 and mixed into the water supply tank 1. Without discharging, it can be reliably discharged to the outside. Further, by connecting the initial drain discharge means 5 to the drain storage tank 14, rust contained in the drain after the initial drain discharge means 5 stops is accumulated in the drain storage tank 14, and the next initial drain discharge is performed. It can be discharged when the means 5 is activated.

[0013]

According to the present invention having the above-described structure, the gas in the drain is removed by the gas separator, and the gas in the drain can be reliably prevented from being mixed into the boiler feed water. . When this gas separator is provided in the water supply tank, the entire drain recovery device can be made compact, and the piping can be easily installed. In addition, the initial drain discharge means discharges the drain collected within a predetermined time after the boiler is started up to the outside, thereby reliably preventing rust in the steam piping from being mixed into the boiler feed water.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water supply tank 2 Drain collection line 3 Gas separator 4 Boiler 5 Initial drain discharge means

Claims (3)

[Claims] 1. A drain recovery device comprising a drain recovery line connected to a water supply tank and a gas separator for separating gas in the drain. 2. The drain recovery device according to claim 1, wherein the gas separator is provided in the water supply tank. 3. A drain connected with a drain recovery line 2 to a water supply tank 1, and provided with an initial drain discharge means 5 for discharging drain collected within a predetermined time after the boiler 4 is started up. Collection device.