San Diego, CA– Continental Controls Corporation, a manufacturer of controls and components for Gas Turbine and Reciprocating engines, has retrofitted several GE Frame 3 and Frame 5 gas turbine fuel systems with their AGV 50 Gas Valve.
Stan Brown is the Chief Controls Coordinator for El Paso Energy in Flagstaff Arizona. Stan is responsible for control systems on Gas Turbines and Gas Engines on the western end of the El Paso Pipeline.
As control systems improved and were updated, Stan was looking to improve the main interface from the control system to gas turbine which is the fuel system. Over the years development of new fuel control valves has provided for better control of the turbines.
In the past hydraulic servo actuated valves was the technology of choice. With advances in electronics and smart valves, the ability to gather and process information locally at the valve has made the use of electronic fuel valves more attractive. Not only can these valves react more quickly, they can start the turbine more reliably and control the turbine in a more stable manner than the older servo actuated valves. These electronic valves now have built in diagnostics and require little or no maintenance.
On the Frame 3 turbines that Stan has upgraded the controls for he has been able to replace both the Ratio Control valve and the Main Fuel Metering valve with a single AGV 50 fuel valve from Continental Controls Corporation.
The two valves were originally required because the turn down ratio of the valve to control effectively at start flows and max flow were too great for valves of that era. Now with improved turn down and because the AGV 50 performs a mass flow calculation in the valve, it is possible to meet this requirement with a single, more reliable, electronic fuel valve. Because the valve is given a command signal to open to a specific flow, not valve position, starting is very repeatable regardless of changes in pressure, ambient temperature, gas temperature or many other variables.
By replacing the old hydraulic valve El Paso has also been able to eliminate unwanted flameouts on the turbine and maintain more stable combustion. During a recent start up Stan says that they started the turbine 12 starts in a row without ever failing to start. This would have been impossible with their previous valve configuration.
The AGV 50 is a much smaller foot print than the large and cumbersome hydraulic valves and installation was simple taking less than 8 hrs. per turbine. Stan has also added an additional safety with the new valves where he verifies that the flow measurement in the valve is within an expected range or he will shut down the turbine. With the previous configuration, this would have required an additionally fuel measurement device where now it is included as a standard feature in the AGV 50.
For start up and in the event of a suspected problem, CCC has provided software diagnostics called Valve Viewer which allows the engineer to see what is being requested of the AGV 50 and what the valve is actually doing.
El Paso has now retrofitted more than 20 GE Frame 3 Turbines in Arizona and New Mexico.