Silica Monitoring For Water Injection System Cuts NOx Emissions At Long Island Peaking Power Plant

By Chris Westlake, Analytical Industry Manager, Power and Water Utilities, ABB and Matthew Gaskin, Lead Engineer, National Grid's Power Engineering Department

A new high pressure water injection system designed to reduce nitrogen oxide emissions from a peaking power plant in New York requires water with an ultra-low silica concentration. The twin-pack Pratt & Whitney kerosene-fired engines have a limit of 20 ppb silica in fuel and water entering the turbines. Higher silica values can coat the turbines, leading to decreased efficiency, engine damage, and costly downtime. Estimates for replacing damaged parts for the plant's 10 engines range as high as $5M.

The Operators and Engineers at National Grid chose the new Navigator 600 silica analyzer from ABB Instrumentation to monitor silica in the water to be injected. The Navigator 600 was selected because this analyzer needs little operator attention and reagent usage is comparably low. It's self-calibrating and selfcleaning, and provides a historical data log of alarms and events.