Gas Turbine Steam Combined Cycle Power Plant: Main Systems and Special Valves

Release time:

2024-03-13

Main system and special valve-1 of gas turbine steam combined cycle power plant With the continuous improvement of gas turbine technology and the increasing proportion of natural gas energy utilization, gas turbine has developed rapidly and is becoming an important power of thermal power in the world and the key equipment of national economic development. With the implementation of the national major project of "west to East Gas Transmission" in China and the construction of LNG import and gas station in the southeast coastal area, gas turbine and its combined cycle power station have a broad prospect of development and application.

Gas steam combined cycle power generation device is to introduce the exhaust gas of gas turbine into the waste heat boiler to generate high temperature and high pressure steam, which drives the steam turbine and the generator to generate electricity. Gas turbine is the main power equipment in the cycle, and the waste heat in its exhaust is used to generate steam and further work in the turbine. It can increase the output by one third without increasing the fuel supply, greatly improve the efficiency, and can burn all kinds of gas or liquid fuel. Now it has become a mature power system which is generally accepted by all countries in the world. Moreover, with the shortage of energy and the increasingly strict environmental requirements in the world, the proportion of combined cycle power generation units in all kinds of power generation equipment is rising rapidly.

There is still a significant gap between the technical level of gas turbine in China and the advanced level in foreign countries. However, in recent years, this situation is changing through the import of equipment and technology.

Characteristics and structural length of valves in gas turbine steam combined cycle power plant

The valves used in gas turbine steam combined cycle power plant have high technical requirements and many varieties and specifications. Even if the model and specification of the same valve, its performance requirements are different:

1) some valves require opening indication.

2) some valves shall be equipped with rain cover.

3) some valves are equipped with imported steel pipes, while some domestic steel pipes have different reserved apertures when they are connected by socket welding, so it is necessary to make sure there is no error in thousands of valves.

4) for valves of the same model and specification, the materials of sealing parts are different due to different media. For example, the medium of the valve in the lubricating oil system is mainly clean lubricating oil, so the filler of the valve in this system cannot use white ink material, which will pollute the lubricating oil and cause damage to the rotating parts.

5) for the filter, heater, valve, etc. on the gas and main fuel pipeline system, its medium is natural gas, its design temperature is 350 ℃, and its design pressure is 5.5mpa. The characteristics of the valves and accessories on this system are not only the hydrostatic strength test, but also the high-pressure seal test. Otherwise, the leakage of natural gas into the atmosphere is very harmful.

6) for valves of the same model and specification, some welding grooves need to be radiographed, while others do not.