Greenwood Solves Poor Controllability with DRAG® Solution

An installed Aux Steam valve at Detroit Edison’s Greenwood power plant is requiring replacement due to its poor controllability. To combat this, CCI will supply a globe valve that incorporates DRAG® technology to control the flow velocity, as well as avoid many of the potential valve failures such as erosion caused by cavitation, abrasion, seat leakage noise, and vibration that leads to costly repairs.

In general, poor valve performance in severe service applications is due primarily to excessive fluid velocity. Until recently, all that could be done to reduce the problems of erratic control in valves was to use mufflers, silencers, lagging, special trim, friction tubes, orifices, series valves, and so on. Although these approaches offered by control valve manufacturers appear to recognize that velocity is the real problem, they still attempt to only contain its effects or shift the problem into a more tolerable area. The reality for maintenance performance is that velocity must be controlled at all valve settings. By forcing process fluid to follow a tortuous path of right angle turns through the trim, damaging velocities are controlled, resulting in the smooth, stable control of the variables such as level, pressure, temperature, and flow. With DRAG® technology, the exact number of turns is engineered to achieve low fluid velocities consistent with the needs of the auxiliary steam application for maximized plant efficiency.

Published in SOLUTIONS Fall 2001