CN212408282U - Steam drainage system - Google Patents

Abstract

The utility model discloses a steam drainage system, which comprises a steam trap module, an emergency drain valve, a drainage receiver and the like; the steam trap module comprises a two-stage series steam trap consisting of a first-stage steam trap and a second-stage steam trap, wherein the second-stage steam trap is provided with a regulating valve, and both the first-stage steam trap and the second-stage steam trap have the functions of water passing and steam blocking; the export of high-pressure steam container connects in the entry of hydrophobic bag, and the export of hydrophobic bag is divided into two strands, and the one strand connects in the entry of emergency drain valve, and another strand connects in the entry of one-level steam trap, and the export of emergency drain valve connects in the first entry of hydrophobic receiver, and the export of one-level steam trap connects in the entry of second grade steam trap, and the first export of second grade steam trap connects in the second entry of hydrophobic receiver, and the export of second grade steam trap second connects in the entry of governing valve, and the export of governing valve connects in the entry of low-pressure steam container. The utility model discloses a two-stage series connection steam trap has solved the hydrophobic problem that exists of nuclear power station steam turbine extraction steam pipe.

Description

A steam drain system

technical field

The utility model belongs to the technical field of nuclear power, in particular to a steam drainage system.

Background technique

The steam turbine of the pressurized water reactor nuclear power plant is a saturated steam turbine, and the steam extraction humidity of the steam turbine is high. During the operation of the unit, there are many drains in the steam turbine extraction pipeline. These drains must be drained in time, but the drain should not be drained at the same time. The steam is discharged, so a steam trap with hydrophobic steam blocking function must be used.

The current hydrophobic systems have the following problems:

(1) When the differential pressure between the inlet and outlet of the steam trap is relatively large, the drainage is not smooth.

The pressure of the steam extraction pipeline of the steam turbine is relatively high, and the pressure and temperature inside the trap and in the pipeline in front of it are relatively high; the drain is discharged to the condenser through the trap, the condenser is negative pressure, and the pressure in the pipeline behind the trap is relatively low; Therefore, the differential pressure between the inlet and outlet of the steam trap is relatively large.

The working principle of the trap is that when there is water in the trap, the trap opens the drain valve to drain water, and when there is no water in the trap, the trap drain valve closes.

For a steam trap with a large differential pressure between the inlet and outlet, when the water level in the steam trap is high and the drain valve is opened to drain water, the interior of the steam trap is connected to the low-pressure pipeline behind the steam trap, and the pressure inside the steam trap decreases rapidly, causing high temperature and high pressure in the steam trap. The drain is quickly vaporized, and the drain valve of the trap is closed immediately, causing the drain to stop. Therefore, the effective drainage time of the trap is short, the drainage efficiency is poor, and the drainage is not smooth.

(2) The steam trap is frequently discharged, and the alternating cold and heat of the pipeline after the steam trap is likely to generate thermal stress, resulting in cracking and leakage of weak links;

Due to the opening of the drain valve, the internal pressure of the trap is suddenly reduced and the water in the valve is vaporized, and the drain valve is quickly closed after a short opening. After the drain valve of the trap is closed, the pressure in the trap gradually returns to normal. Since not much water was discharged after the drain valve was opened last time, the water level in the trap quickly prompted the drain valve of the trap to open again.

The drain valve of the steam trap is opened to discharge the high-temperature gas, closed again for a short time, and then opened again, again and again, this high-frequency switch, on the one hand, makes the drainage of the steam trap not smooth, and on the other hand makes the pipeline behind the steam trap withstand high-frequency The temperature and pressure are alternated, and the pipeline produces fatigue cracking in the weak link.

(3) The emergency trap valve is frequently opened and closed, which makes it easy to be damaged. The alternating cold and heat of the pipeline after the trap is likely to generate thermal stress, resulting in cracking and leakage of weak links;

Due to the poor drainage of the trap, the drainage accumulated to the drainage bag, which triggered the action of the water level switch, which in turn triggered the opening of the emergency drainage valve. After the emergency drainage valve was opened, the water level decreased and the emergency drainage valve was closed. It rises rapidly and the emergency valve opens again. Frequent opening and closing of the emergency drain valve will increase the vibration of the emergency drain valve and its pipeline, resulting in damage to the emergency trap. The pipeline behind the emergency trap is also subjected to high-frequency temperature and pressure changes, and fatigue cracks occur in the weak links of the pipeline.

SUMMARY OF THE INVENTION

The purpose of the utility model is to provide a steam drainage system in view of the problems existing in the water conveyance of the steam extraction pipeline of the steam turbine of the nuclear power plant at present.

In order to achieve the above object, the utility model adopts the following technical solutions to realize:

A steam trapping system, comprising a trap module, a trapping bag, an emergency drain valve, a high-pressure steam vessel, a trapping receiver and a low-pressure steam vessel; wherein,

The steam trap module includes a two-stage series steam trap composed of a first-stage steam trap and a second-stage steam trap. A regulating valve is installed on the second-stage steam trap. Both the first-stage steam trap and the second-stage steam trap have the function of passing water and preventing steam;

The outlet of the high-pressure steam container is connected to the inlet of the drain bag, and the outlet of the drain bag is divided into two parts, one is connected to the inlet of the emergency drain valve, the other is connected to the inlet of the first-level steam trap, and the outlet of the emergency drain valve is connected to the The first inlet of the hydrophobic receiver, the outlet of the primary trap is connected to the inlet of the secondary trap, the first outlet of the secondary trap is connected to the second inlet of the hydrophobic receiver, and the second outlet of the secondary trap is connected to The inlet of the regulating valve, the outlet of the regulating valve is connected to the inlet of the low pressure steam container.

A further improvement of the utility model is that a liquid level switch is installed in the hydrophobic bag.

Compared with the prior art, the utility model has the following advantages:

The utility model provides a steam draining system, which has obvious advantages in the following aspects compared with the currently commonly used system:

(1) Use smooth drainage in a high differential pressure system.

The utility model provides a steam drainage system, which adopts two-stage series-connected steam traps, and the drainage of the primary steam trap enters the secondary steam trap. When the primary trap is draining, the secondary trap is closed; the water in the primary trap is discharged into the secondary trap to expand, depressurize, and cool down to generate drainage and steam. The regulating valve of the secondary trap can adjust the secondary trap. The pressure in the first-stage steam trap makes the differential pressure between the first-stage steam trap and the first-stage steam trap smaller, which avoids the vaporization of the water in the steam trap when the first-stage steam trap is drained, and the drainage is more thorough. After the steam in the secondary trap is discharged, its internal pressure and temperature decrease, and the differential pressure with the pipeline at the rear of the trap decreases. When the secondary trap is drained, the water in the secondary trap will not suddenly vaporize. , the trap drainage is smooth.

(2) Part of the heat and working fluid can be recovered.

By adjusting the pressure in the secondary trap through the regulating valve of the secondary trap, the steam and water in the secondary trap can be recovered to the steam and water system with lower pressure, and part of the heat and working fluid can be recovered, which is energy-saving. Effect.

(3) Frequent opening of emergency traps is avoided, and damage to emergency traps is reduced.

Due to the smooth drainage of the trap, it is difficult for the accumulated water to reach the trap bag, so the emergency trap will not be opened frequently, reducing the probability of damage to the emergency trap.

(4) Avoid thermal stress fatigue cracking of the pipeline after the steam trap due to alternating temperature and pressure.

Description of drawings

FIG. 1 is a structural block diagram of a steam drainage system of the present invention.

Description of reference numbers:

1. Trap module, 2. Drain bag, 3. Emergency drain valve, 4. Primary trap, 5. Secondary trap, 6. Regulating valve, 7. High pressure steam vessel, 8. Drain receiver, 9. Low pressure steam container.

Detailed ways

The present utility model will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 1 , a steam drainage system provided by the present invention includes a steam trap module 1, a steam drainage bag 2, an emergency drainage valve 3, a high-pressure steam container 7, a drainage receiver 8 and a low-pressure steam container 9; wherein, The steam trap module 1 includes a two-stage series steam trap composed of a primary steam trap 4 and a secondary steam trap 5. A regulating valve 6 is installed on the secondary steam trap 5. Both the primary steam trap 4 and the secondary steam trap 5 have The function of passing water and blocking steam; the outlet of the high-pressure steam container 7 is connected to the inlet of the water-repellent bag 2, and the outlet of the water-repellent bag 2 is divided into two parts, one is connected to the inlet of the emergency drain valve 3, and the other is connected to the first-level drain The inlet of the trap 4, the outlet of the emergency drain valve 3 is connected to the first inlet of the drain receiver 8, the outlet of the primary trap 4 is connected to the inlet of the secondary trap 5, and the first outlet of the secondary trap 5 is connected to The second inlet of the drain receiver 8 and the second outlet of the secondary trap 5 are connected to the inlet of the regulating valve 6 , and the outlet of the regulating valve 6 is connected to the inlet of the low-pressure steam container 9 .

Among them, the water-repellent bag 2 is equipped with a liquid level switch. When the liquid level in the water-repellent bag 2 is higher than the set value, the liquid level switch acts to open the emergency drain valve 3 in a chain, and the liquid level in the water-repellent bag 2 does not exceed the set value. , the emergency drain valve 3 is interlocked to close.

The utility model adopts two-stage series-connected steam traps, and the drainage of the first-stage steam trap 4 enters the secondary steam trap 5 . When the primary steam trap 4 is draining, the secondary steam trap 5 is closed; the water in the primary steam trap 4 is discharged into the secondary steam trap 5 to expand, depressurize, and cool down to generate drainage and steam, which pass through the secondary steam trap 5. The regulating valve 6 can adjust the pressure in the secondary steam trap 5 to make the pressure difference between the primary steam trap 4 and the primary steam trap 4 smaller, so as to avoid the vaporization of the water in the steam trap when the primary steam trap 4 drains water, and the drainage is more thorough. After the steam in the secondary steam trap 5 is discharged, its internal pressure and temperature decrease, and the differential pressure with the pipeline at the rear of the steam trap decreases. It will suddenly vaporize, and the steam trap will drain smoothly.

A steam draining system provided by the utility model, when working, comprises the following steps:

The hydrophobicity in the high-pressure steam vessel 7 enters the primary trap 4 through the trapping bag 2. When the hydrophobicity in the primary trap 4 accumulates to a certain extent, the trap valve in the primary trap 4 is opened to discharge the hydrophobicity into the secondary trap After the drain in the primary steam trap 4 is exhausted, the steam trap of the primary steam trap 4 is closed;

The drain in the primary steam trap 4 is discharged into the secondary steam trap 5 and then expands and reduces the pressure, producing water and steam with lower pressure. The steam enters the low pressure steam container 9 under the control of the regulating valve 6, and the water accumulates to a certain level. Automatic discharge to the hydrophobic receiver 8 after the level;

The pressure in the secondary trap 5 is controlled by adjusting the opening of the regulating valve 6 so that the pressure is higher than the pressure in the drain receiver 8 and higher than the pressure in the low-pressure steam container 9, so that the pressure in the secondary trap 5 is The steam can enter the low pressure steam container 9, so that the water in the secondary trap 5 can enter the drain receiver 8;

When the equipment in the steam trap module 1 fails and the drainage is not smooth, the drainage accumulates in the drainage bag 2 and triggers the liquid level high switch, the emergency steam trap 3 opens, and the drainage is discharged into the drainage receiver 8 .

Claims (2)

1. The steam drainage system is characterized by comprising a steam trap module (1), a drainage bag (2), an emergency drainage valve (3), a high-pressure steam container (7), a drainage receiver (8) and a low-pressure steam container (9); wherein,

the steam trap module (1) comprises a two-stage series steam trap consisting of a first-stage steam trap (4) and a second-stage steam trap (5), the second-stage steam trap (5) is provided with a regulating valve (6), and the first-stage steam trap (4) and the second-stage steam trap (5) have the functions of water and steam passing and blocking;

the export of high pressure steam container (7) is connected in the entry of drain bag (2), the export of drain bag (2) is divided into two strands, the one strand is connected in the entry of emergency drain valve (3), another strand is connected in the entry of one-level steam trap (4), the export of emergency drain valve (3) is connected in the first entry of hydrophobic receiver (8), the export of one-level steam trap (4) is connected in the entry of second grade steam trap (5), the first export of second grade steam trap (5) is connected in the second entry of hydrophobic receiver (8), second grade steam trap (5) second export is connected in the entry of governing valve (6), the export of governing valve (6) is connected in the entry of low pressure steam container (9).

2. A steam trap system according to claim 1 wherein the trap (2) incorporates a level switch.

Images