The primary objectives of on-line cleaning are to maintain the cleanliness of a gas turbine compressor after off-line washing, to maintain power and efficiency by minimizing ongoing losses, and to extend the operating period between shut-downs required for offline (crank) washing.
On-line gas turbine washing for fouling control has become increasingly important with base load combined cycle plants and CHP plants. It is also essential for gas turbines in mechanical drive service, where little or no redundancy is installed and where the downtime associated with crank washing must be minimized.
This article contains excerpts from the paper, “Gas turbine performance and maintenance” presented at the 2013 Turbomachinery Symposium by Rainer Kurz of Solar Turbines Incorporated, Cyrus Meher-Homji of Bechtel Corporation, Klaus Brun and Jeff Moore of Southwest Research Institute and Francisco Gonzalez of Enterprise Products.
On-line wet cleaning is performed while the gas turbine is in operation and at load. The procedure involves the injection of a mixture of water and chemical detergent via atomizing spray nozzles positioned around the compressor air intake plenum. This is followed by a flushing period using pure water. With on-line cleaning, it is mandatory to use demineralized water for preparing the cleaning fluid and for flushing. This is because the turbine is in operation, and high temperature corrosion damage may occur if sodium or other contaminant metals enter the combustion path.
Read the full article from Turbomachinery magazine here.