JPS6042844B2 - Condensate recovery method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a condensate recovery method for recovering condensate generated in steam-using equipment and returning it to a boiler.

Almost all of the steam sent out from the boiler is not recovered, and the shortage is made up with low-temperature make-up water.

Therefore, a method can be considered in which low-temperature make-up water is pressurized by a water supply pump, jetted out from the spout of the ejector, condensate is guided to the suction hole of the ejector, and the condensate is pumped together with the low-temperature make-up water from the diffuser of the ejector to the boiler. In this case, since the feed water pump is used to pressurize low-temperature make-up water, there is no need to take special consideration to the occurrence of cavitation, which is a problem when pumping high-temperature condensate. requires a large amount of low-temperature make-up water,
Even though there is condensate that can be recovered, some of the condensate may not be recoverable due to the amount of evaporation in the boiler.
The present invention aims to provide a condensate recovery method that has good heat recovery efficiency and is easy to implement.

Next, a description will be given based on a diagram showing an outline of an apparatus for carrying out the method of the present invention.

Like parts in each figure use the same reference numerals as in the lower numbered figures. Referring to FIG. 1, a water supply tank 1 stores room-temperature water that has been subjected to soft water treatment or pure water treatment and is suitable as boiler feed water.

Makeup water in the tank 1 passes through a water supply passage 2 and is pumped to a boiler 4 by a water supply pump 3. The steam evaporated in the boiler 4 is sent through the steam transport passage 5 to the steam-using equipment 6, where it works, becomes condensate, is discharged from the steam trap 7, and passes through the condensate passage 8 to the accumulator 9. Water is stored.
Generally speaking, the amount of condensate transported to accumulator 9 is
The amount of evaporation is at most 80-90%. Accumulator 9 buffers load fluctuations. A portion of the condensate in the accumulator 9 passes through a condensate bypass passage 10 and enters the water supply passage 2 before the water supply pump 3, where it is mixed with low-temperature make-up water.

The amount of condensate to be mixed is adjusted by the throttle means 11 so that the temperature of the mixed water does not exceed the allowable temperature range of the water supply pump 3 and cause technically difficult problems such as cavitation.The throttle means 11 is variably adjusted. A throttle valve or orifice is used, but this is unnecessary if the pipe diameter of the passage 10 is appropriately designed.
Mixed water with condensate from the boiler is pressurized by the water supply pump 3, is ejected from the spout of the ejector 12, passes through the water supply passage 2, and is fed under pressure to the boiler 4.

At this time, the condensate of the accumulator 9 is guided through the suction passage 13 to the jet stream of the working sector 12, sucked in, and sent out from the diffuser to the water supply passage 2. Therefore, more condensate can be pumped to be mixed with the low-temperature make-up water, increasing the amount of condensate that can be recovered. Reference numeral 14 denotes a bleed passage for discharging the re-evaporated steam in the accumulator 9 to the water supply tank 1, thereby creating a pressure gradient that causes the steam trap 7 to operate.

15 is a diaphragm means.

The pump 3 may be controlled by detecting the amount of water in the boiler 4.

Referring to FIG. 2, an auxiliary water supply pump 16 is arranged in series with the water supply pump 3.

The auxiliary pump 16 is connected in series with the feed water pump 3 to increase the pump head, and also provides a bypass passage 17 to the boiler 4.
By providing this, a large amount of water can be supplied when the load suddenly changes. 1
Reference numeral 8 denotes a valve provided in the bypass 17, which detects and controls the amount of water in the boiler 4 or is operated manually.

It is also possible to constantly send a small amount of water through the bypass passage 17 with the valve 18 in a half-open state. If the capacity of the auxiliary pump 16 is large, a loop passage 19 to the tank 1 may be provided. 20 is a valve.

Regarding FIG. 3, an auxiliary water supply pump 16 is arranged in parallel with the water supply pump 3.

21 is a bypass passage, and 22 is a check valve.

In this case, the water supply pump 3 can be designed for condensate recovery, and the auxiliary pump 16 can be operated only when the load suddenly changes. With respect to FIG. 4, there is a mixing sector 23 between the auxiliary pump 16 and the feed pump 3.
This is an intervening method.

This is because when the discharge pressure of the auxiliary pump 16 becomes higher than the pressure of the accumulator 9, the water discharged from the auxiliary pump 16 can suck and mix the condensate of the accumulator 9. The condensate bypass passage 10 and the bleed passage 14 communicate through a passage 24, and valves 25 and 26 are provided. When the valve 26 is opened, the pressure in the accumulator 9 can be drawn out in the mixer sector 23. If valves 25 and 26 are both opened, condensate and re-evaporated steam can be drawn in sector 23. ) Regarding FIG. 5, when the discharge pressure of the auxiliary pump 16 is higher than the pressure of the accumulator 9, as a method of mixing condensate with make-up water, a loop passage 27 is provided in the water supply pump 3, a work sector 28 is arranged, and the condensate water is mixed with the make-up water. The condensate passing through the water bypass passage 10 can also be sucked into the working sector 28 using a part of the water discharged from the water supply pump 3.

Regarding FIG. 6, the function of the working sector 28 in FIG. 5 is also performed by the working sector 12.

29 is a loop passage, and 30 is a restricting means.

Throttle valve 31 controls the pressure of water returning through loop passage 29. As described above, according to the present invention, a part of the condensate can be used as driving water for the industrial sector, and the amount of low-temperature make-up water can be reduced by that amount, which increases the amount of condensate that can be recovered and The recovery rate will be higher.

Moreover, it can be easily carried out using a general water pump and industrial equipment.

[Brief explanation of drawings]

1 to 6 schematically show an apparatus for carrying out the condensate recovery method of the present invention. 1 is a water supply tank, 2 is a water supply passage, 3 is a water supply pump, 4 is a boiler, 9 is an accumulator, 10 is a condensate bypass passage, 12 is a working sector, and 13 is a suction passage.

Claims (1)

[Claims] 1 Pressurize the low-temperature make-up water to the boiler with a water supply pump and jet it out from the ejector's spout, guide the condensate to the ejector's suction port, and pump the condensate together with the low-temperature make-up water from the ejector's diffuser to the boiler. A condensate recovery method characterized in that a part of the condensate is added to low-temperature make-up water before the water supply pump.