KR20040100504A - Valve closing system repairing bypass line in complex power generation plant - Google Patents

Abstract

PURPOSE: A valve opening/closing system installed on a bypass line in a complex power generation plant is provided to protect workers and facilities by checking the locking condition of valves and locking the other valves while repairing the bypass line. CONSTITUTION: A valve opening/closing system installed on a bypass line is composed of a first valve(110) installed at a steam inlet of the bypass line(2), a second valve(120) installed at a steam outlet of the bypass line, and third valves(130,140) installed at cooling water pipes(3) for injecting cooling water into the inside of the bypass line. Key boxes(111,121,131,141) are installed at the first, second and third valves. The bypass line and the cooling water pipe are opened/closed by the rotation of keys(112,122,132,142) inserted into the key boxes. Key slots are formed at the key box installed at the second valve. The key(122) for the second valve is rotated only when keys(112,132,142) for the first and third valves are inserted into the key slots, and opens/closes the second valve.

Description

VALVE CLOSING SYSTEM REPAIRING BYPASS LINE IN COMPLEX POWER GENERATION PLANT}

The present invention relates to a bypass line of a combined cycle power plant having a generator associated with a heat recovery steam generator (HRSG), and in particular, does not transfer high-temperature, high-pressure steam discharged from the waste heat recovery boiler to a steam turbine. The present invention provides a valve opening / closing system for worker safety when bypassing the bypass line.

Combined cycle power plant has a gas turbine that produces large amounts of electricity by burning fuel, a waste heat recovery boiler that recovers high-temperature combustion gases generated from the gas turbine, and generates high-temperature, high-pressure steam, and high-temperature, high pressure steam that is discharged from the waste heat recovery boiler. It is divided into steam turbines that produce electricity by using.

In this combined cycle power plant, a duct connects the waste heat recovery boiler to the steam turbine, and a bypass line is connected to the duct. The high temperature and high pressure steam generated from the waste heat recovery boiler enters the steam turbine through the duct, but when the steam turbine is stopped due to failure or periodic inspection, the high temperature and high pressure steam generated from the waste heat recovery boiler passes the bypass line. Through the atmosphere. However, this high temperature and high pressure steam is a source of air pollution, and should be discharged by lowering the temperature.

1 is a schematic diagram of a bypass line between a waste heat recovery boiler and a steam turbine of a combined cycle power plant according to the prior art.

As shown in FIG. 1, the high temperature and high pressure steam flows from the right side of the pipe diagram, that is, the waste heat recovery boiler 1, and is discharged to the low pressure steam through the first valve 11 and the second valve 12. In this process, cooling water is injected into the bypass line 2 to lower the temperature of the steam. In order to inject the coolant in this way, in the bypass line 2, the coolant pipe 3 is connected between the first and second valves 11 and 12, and the coolant supplied through the coolant pipe 3 is bypassed. It sprays into the pass line 2, and cools hot steam.

As shown in FIG. 1, the coolant pipe 3 is branched, and third and fourth valves 13 and 14 are installed in each branch pipe to control the injection amount of the coolant, and in some cases, the coolant The pipe 3 can be opened and closed by the third valve 13 without branching.

In the bypass line 2 having such a structure, conventionally, after controlling the control of each valve 11, 12, 13, 14 as follows, the bypass line 2 was checked and repaired.

First, the first, third, and fourth valves 11, 13, and 14 are manual valves, and the second valve 12 is a motor operated valve. The four valves 11, 13 and 14 are directly controlled by the operator by hand, and the opening of the second valve 12 is controlled by the operator in the control room. The problem with the bypass line 2 configured as described above is that although the operator manually closes the first, third, and fourth valves 11, 13, and 14, it may not be completely closed. It may not be made by mistake. In this abnormal state, the control room is mistaken for the normal state and closes the second valve 12, and an operator who does not recognize this state enters the bypass line 2 and checks and repairs the interior. The high temperature, high pressure steam or cooling water flows into the bypass line 2 where the worker is located through the first, third, and fourth valves 11, 13, 14 in a state. In this state, the second valve 12 is in a completely closed state, and steam may accumulate inside the bypass line 2 where the worker is located, causing a safety accident.

Further, even if the worker does not enter the bypass line 2, the bypass line 2 corresponding to the second valve 12 and the first, third, and fourth valves 11, 13, and 14 may be connected to the bypass line 2, respectively. May have fatal adverse effects.

The present invention has been proposed to solve the problems of the prior art as described above, the state in which the locked state of the valve is confirmed so that the high temperature and high pressure steam does not flow into the bypass line during the inspection and maintenance of the bypass line It is an object of the present invention to provide a valve opening and closing system in which other valves are locked.

1 is a schematic diagram of a bypass line between a waste heat recovery boiler and a steam turbine of a combined cycle power plant according to the prior art,

2 is a schematic diagram of a bypass line between a waste heat recovery boiler and a steam turbine of a combined cycle power plant according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

1: waste heat recovery boiler

2: bypass line

3: cooling water pipe

11, 12, 13, 14, 110, 120, 130, 140: valve

111, 121, 131, 141: keybox

112, 122, 132, 142: keys

The present invention for achieving the above object is in the valve opening and closing system installed in the bypass pipe of the combined cycle power plant is installed in the bypass pipe for bypassing the steam supplied from the waste heat recovery boiler to the steam turbine, the bypass pipe A first valve installed at a steam inlet of the second valve, a second valve installed at a discharge port of the bypass pipe for discharging the introduced steam, and a third valve installed at a cooling water pipe connected to inject coolant into the bypass pipe The first and third valves are provided with a key box, and as the key inserted into the key box rotates to open / close the bypass pipe and the cooling water pipe, and the key box installed on the second valve. A key slot is formed in which a key for opening / closing the first and third valves is inserted, and a key of the first and third valves must be inserted into the key slot. It is characterized in that the rotatable and configured to open / close the second valve.

The cooling water pipe of the present invention is branched into a plurality of branches, it is preferable that the branched cooling water pipes are each provided with a third valve.

More preferably, the first and third valves are manual valves, and the second valves are mechanical valves.

In the following, with reference to the accompanying drawings a preferred embodiment of the valve opening and closing system for safety at the bypass line maintenance of the combined cycle power plant according to the present invention will be described in detail.

2 is a schematic diagram of a bypass line between a waste heat recovery boiler and a steam turbine of a combined cycle power plant according to an embodiment of the present invention.

As shown in FIG. 2, the first to fourth valves 110, 120, 130, and 140 installed in the bypass line 2 and the coolant pipe 3 are respectively the key boxes 111, 121, 131, and 141. And a valve capable of withdrawing the keys 112, 122, 132, and 142 inserted into the key boxes 111, 121, 131, and 141 only when the valves 110, 120, 130, and 140 are completely closed. admit. As such, the valves 110, 120, 130, 140 with the key boxes 111, 121, 131, 141 have been developed to lock the open or closed state of the valves 110, 120, 130, 140. As the valves, detailed descriptions thereof are omitted since they are already commercially available.

The first valve 110 and the third and fourth valves 130 and 140 installed at the inlet side of the bypass line 2 into which the high temperature and high pressure steam flows, respectively, are manual valves. When the keys 112, 132, and 142 corresponding to the valves 110, 130, and 140 are rotated by locking, the valves 110, 130, and 140 are closed, and conversely, the keys 112, 132, and 142 are unlocked. When rotated, the valves 110, 130, 140 are opened. The keys 112, 132, and 142 are withdrawn from the key boxes 111, 131, and 141 only when the keys 112, 132, and 142 are rotated by the locking, that is, when the valves 110, 130, and 140 are closed. can do.

On the other hand, the second valve 120 is a mechanical valve, the key box 121 of the second valve 120 has a total of four key slots are formed, three of the first, third, fourth in the key slots Three keys 112, 132, 142 corresponding to the valves 110, 130, 140 are inserted. The key 122 inserted into the other key slot is a key for opening / closing the second valve 120 and includes three keys corresponding to the first, third, and fourth valves 110, 130, and 140. All of the keys 112, 132, and 142 must be inserted into the key slots so that the key 122 corresponding to the second valve 120 can rotate from unlocking to locking or vice versa. Here, the remote control of the second valve 120 in the control room is possible only when the key 122 corresponding to the second valve 120 is positioned in the locked state, and in the unlocked state, the second valve 120 may be Remote control is not possible.

In the valve opening and closing system for safety at the time of repairing the bypass line 2 of the combined cycle power plant having such a configuration, the operator of the first valve 110, the third valve 130, the fourth valve 140 In order to lock the valves 110, 130, and 140 by rotating the keys 112, 132, and 142 of the key boxes 111, 131, and 141 installed in the valves 110, 130, and 140, respectively. 112, 132, 142 are recovered. Then, the respective keys 122 are inserted into the key slots formed in the key box 121 of the second valve 120, and the keys 122 corresponding to the opening and closing of the second valve 120 are rotated by locking. 122).

The key 122 corresponding to the recovered second valve 120 is stored in the control room. According to this order, the second valve 120 is locked after the first valve 110, the third valve 130, and the fourth valve 140 are completely locked, so that the first valve 110 and the first valve 110 are locked. It is safe even if an operator works inside the bypass line 2 located between the second valves 120.

When the inspection and repair of the bypass line 2 are completed, the second, fourth, third, and first valves 120, 140, 130, and 110 are opened in the reverse order of the locking sequence.

As described in detail above, the valve opening and closing system for safety at the maintenance of the bypass line of the combined cycle power plant of the present invention is installed on the bypass line by installing a mechanical locking device between the manual valve and the mechanical valve on the bypass line. It has the advantage of protecting the working people and equipment.

The technical idea of the valve opening and closing system for safety at the repair of the bypass line of the combined cycle power plant of the present invention has been described above with the accompanying drawings, but this is illustrative of the best embodiment of the present invention by way of example. It is not limited.

Claims (3)

In the valve opening and closing system installed in the bypass pipe of the combined cycle power plant is installed in the bypass pipe for bypassing the steam supplied from the waste heat recovery boiler to the steam turbine, A first valve installed at a steam inlet of the bypass pipe; A second valve installed at an outlet of the bypass pipe for discharging introduced steam; A third valve installed in the coolant pipe connected to inject coolant into the bypass pipe, Key boxes are installed in the first and third valves, and the bypass pipe and the cooling water pipe are opened / closed as the key inserted into the key box rotates, and the first box is installed in the key box installed in the second valve. And a key slot into which a key for opening / closing a third valve is inserted is formed, and a key of the first and third valves must be inserted into the key slot so that the key of the second valve can be rotated to open / close the second valve. The valve opening and closing system installed in the bypass pipe of the combined cycle power plant, characterized in that for closing. The method of claim 1, The cooling water pipe is branched into a plurality of branches, the branched cooling water pipe opening and closing system installed in the bypass pipe of the combined cycle power plant, characterized in that each of the third valve is installed. The method according to claim 1 or 2, The first and third valves are manual valves, the second valve is a valve opening and closing system installed in the bypass pipe of the combined cycle power plant, characterized in that the mechanical valve.