JPS61228205A - Recirculation system of deaerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a deaerator recirculation system used for heating deaeration of feed water and for storing a condensate system full of water.

[Technical background of the invention and its problems] Generally, at the time of plant start-up or start-up Jfi machine, the deaerator recycler of the feed water is A method of heating and degassing using circulation is used.

Conventionally, in this method, a separate pump called a deaerator recirculation pump was installed for the sole purpose of recirculating the feedwater, and the water was passed from the deaerator downpipe to the condensate line at the deaerator inlet via the recirculation pump. By providing a return device, the feed water was circulated, and at the same time, auxiliary steam was supplied to the deaerator to perform heating deaeration.

However, in this method, the deaerator recirculation pump and its associated control device and piping had to be installed separately, which was very uneconomical.

Alternatively, without installing a deaerator recirculation pump, feed water can be routed to the condenser using an overflow line or a water level reduction line from the deaerator storage tank to the condenser, and then degassed using the condensate pump. A method of recirculating the gas back to the gas chamber has also been adopted, but in this case, the temperature was raised to 108℃ using the degasser.
The feed water that was heated to about
Since the temperature drops to around 0℃, when heating the temperature to 108℃ using auxiliary steam in the deaerator, a large amount of auxiliary steam is required, which is a huge waste of energy, and the auxiliary steam supply equipment is also large. The problem was that things were needed. Also, since the water supply flow m during heating deaeration is small,
When a condensate pump is used, there is a problem in that the flow rate is restricted and the motor output is wasted.

[Object of the Invention] The present invention has been made in response to such conventional circumstances, and provides an inexpensive deaerator recirculation pump that can omit a separate deaerator recirculation pump and does not waste energy. It is intended to provide a circulatory system.

[Summary of the Invention] That is, the present invention provides a condensate line that has a low-pressure feedwater heater and supplies condensate from a condenser to a deaeration heating chamber of a deaerator;
a transfer line that transfers drain from the low-pressure feed water heater to a heater drain tank; and a heater drain pump that has one end connected to the heater drain tank and the other end connected to the condensate line upstream of the low-pressure feed water heater. and a water supply line having a boiler water supply pump for supplying condensate in the deaerator storage tank of the deaerator to the boiler, the water supply line branching from upstream of the boiler water supply pump. The deaerator recirculation system is characterized in that a circulation line having a flow control valve connected to the heater drain tank is arranged.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, reference numerals 1, 2, and 3 indicate low-pressure feed water heaters installed in the condensate system, and during load operation of the turbine, oil and steam are used. is supplied to each feedwater heater 1.2.3 to heat the condensate.

The bleed steam condenses in the feedwater heaters 1.2.3 to become drain and is sent via drain control valves 4.5 to the respective feedwater heaters of the next low pressure stage. Drain accumulated in the feed water heater 3 at the lowest pressure stage is sent to the heater drain tank 6, pressurized by the heater drain pump 7, and recovered to the condensate line 8.

The drain flow rate sent to the condensate line 8 by the heater drain pump 7 is controlled by adjusting the opening of the drain control valve 10 by a water level controller 9 installed in the heater drain tank 6, so that the water level in the heater drain tank 6 is always kept constant. It is adjusted so that The heater drain is sent to the deaerator 11 together with condensate.

During normal operation, the deaerator 11 is supplied with turbine oil vapor sent through the bleed pipe 12 to heat and degas the condensate. However, since the extracted steam is not alive until the turbine reaches load operation, when the plant is started up before then, auxiliary steam is supplied to the deaerator via the control valve 13 and used for heating degassing. .

Degassing P! Supplying auxiliary steam to No. 11 for heating and deaeration keeps the amount of dissolved oxygen in the water supplied to the boiler low.
This is to ensure that the plant starts up smoothly, but at the initial stage of the plant start-up, when the water has not yet been sent to the boiler, in order to degas the 1 cm of water that has accumulated in the deaerator water storage tank 14, Conventionally, deaerator recirculation is performed by a separate device, as described above, and heating deaeration is performed using auxiliary steam.

In this embodiment, a recirculation pipe 17 is arranged to branch from a downpipe 16 that sends water from the deaerator water storage tank 14 to the boiler feed pump 15 and connect to the heater drain tank 6, and to adjust the circulating water level. It is possible to send water in the deaerator water storage tank 14 to the heater drain tank 6 via the control valve 18.

In the deaerator recirculation system configured as described above, the turbine bleed steam is not alive until the turbine reaches load operation, so no heater drain flows into the heater drain tank 6. Therefore, the water in the deaerator water storage tank 14 can be recirculated at the rated flow rate (1) of the heater drain pump 7. At this time, the heater drain control valve 10 only needs to control the water level of the heater drain tank 6 in the same way as during normal operation, and no special control device is required. The water supply m flowing into the heater drain tank 6 is regulated by the control valve 18 while controlling the level of the heater drain tank 6.

In a deaerator recirculation system configured in this way, all that is required is to install the piping and control valve that connect the deaerator downcomer pipe 16 and the heater drain tank 6, and then use the normally installed equipment to carry out deaeration. Air recirculation can be performed. Also, unlike when using a condensate pump, there is no heat loss in the condenser,
Since the heater drain pump 7 can be operated at the rated flow m, economical heating and deaeration can be performed without loss of motor output.

FIG. 2 shows an embodiment in which the deaerator recirculation system described above is used for a purpose other than heating and degassing.

In other words, this is an example in which the condensate system is used to store water with a high temperature of 92211 degrees when the plant is shut down for a long period of time.

Generally, when a plant is kept full of water for long-term shutdown, condensate water is replaced with water with a high hydrazine concentration, but conventionally a condensate pump has been used.

In this embodiment, water in the deaerator water storage tank 14 is circulated using the heater drain pump 7 as in the case of heating deaeration.
Chemical injection pipe 19 installed in the deaerator downpipe 16, etc.
It is possible to inject hydrazine into the water and replace it with water with a high hydrazine concentration.

A make-up water pipe 20 for supplying make-up water to the heater drain tank 6 is installed, and by injecting water from this pipe, the deaerator can also be filled with water.

[Effects of the Invention] As described above, according to the deaerator recirculation system of the present invention,
Water in the deaerator water storage tank can be efficiently circulated without installing a separate deaerator recirculation pump. Furthermore, hydrazine can be reliably injected into the condensate system.

[Brief explanation of drawings]

FIG. 1 is a piping system diagram showing a deaerator recirculation system according to one embodiment of the present invention, and FIG. 2 is a piping system diagram showing another embodiment of the present invention. 1.2.3...Low pressure water heater 4.5...Heater drain control valve 6...Heater drain tank 7...
... Heater drain pump 8 ... Condensate line 9 ... Heater drain tank water level controller 1
0...Drain control valve 11...Deaerator 12...Bleed pipe 13...Auxiliary steam Control valve 14...
...... Deaerator water storage tank 15 ...... Boiler water supply pump 16 ...... Deaerator downpipe 17 ...... Deaerator Recirculation pipe 18...
...Deaerator recirculation control valve 19 ... Chemical injection pipe 2o ... Auxiliary water supply pipe Representative Patent Attorney Suyama Sa - Figure 1

Claims (1)

[Claims] (1) A condensate line that has a low-pressure feedwater heater and supplies condensate from the condenser to the deaeration heating chamber of the deaerator, and a transfer line that transfers drain from the low-pressure feedwater heater to the heater drain tank. a drain line having a heater drain pump connected at one end to the heater drain tank and connected at the other end to the upstream side of the low-pressure feed water heater in the condensate line; a water supply line having a boiler water supply pump for supplying condensate to the boiler, and a circulation line having a flow rate control valve branching from the boiler water supply pump upstream of the water supply line and connected to the heater drain tank. A deaerator recirculation system characterized by being arranged.