AVS - Drain Valve applications

The worldwide introduction of wind, solar power and other renewables create an increasingly flexible demand on gas fired power stations to balance the grid. To operate in a reliable, quick, modulating and start/stop regime, some improvements are necessary.

To start and to stop a modern CCGT installation takes time and cannot be done instantaneously. The gas turbine needs to be warmed through as well as the rest of the power plant, the HRSG, (Heat Recovery Steam Generator) downstream of the gas turbine, the interconnecting steam pipework, the steam turbine and all other balance of plant items.

This all must be done as quickly as possible to limit the starting costs and to supply as soon as possible to the grid.

In the European markets the driving factor is high fuel costs, reducing the need for full speed no load, however in the USA the driving factor is to reach emission values as soon as possible.

For all CCGT plants the demand for being reliable and the need to be able to start the installation, to supply to the grid, is the single most important driving factor.

The AVS Solution
Advanced Valve Solutions has a bespoke package of dedicated products to solve these problems, based on our specific and extensive experience in these types of operating regimes.

With this package in place, it leads to reduced maintenance costs, to reduce starting time and to upgrade the reliability of your existing installation. With many years of experience and a group of high qualified European manufacturers supporting our performance, we deliver a complete solution.

Drain Valves
A huge concern is the condition of the different types of drain valves on site.

The continuous, the dis-continuous blow down and the super heater drain valves must be monitored carefully.

In a start-stop regime these valves are in operation daily, dealing with the most aggressive process conditions seen on site with high pressure and temperature water/steam and flashing conditions.

We prefer an angle type valve with an increased outlet diameter, fitted with a quick changeable trim and a separate seat and control edge. This allows quick maintenance and extended service life.

Sometimes modifications on the pipe work arrangements are beneficial. The preferred location is always close to the flash-drain tank.

An additional throttling plate can be used to control the back pressure between the valve and the drain vessel in case the valve is located further away.

Tel: 01270 586 944
Email: info@advancedvalvesolutions.co.uk
Web: www.advancedvalvesolutions.co.uk

Published in Valve User Magazine Issue 50