Presently we are using IL make pressure control valve (PCV) for controlling the pressure (60 Kg/cm2 to 30 Kg/cm2) of natural gas of inlet of Gas turbine (Frame-V). PCV actuator diaphragm is operated by instrument air as per signal from DCS.

Instrument air is supplying by instrument air compressor. Presently we are having problem in compressor to run continuously, and we have to stop instrument air compressor permanently.

Without instrument air we cannot operate the PCV in auto and not controlled the pressure of inlet of gas turbine. As per our present situation, only air is required to PCV & ESD of gas turbine. No other requirement of instrument air. So we have to run compressor only for gas turbine inlet pressure control valve & ESD.

We want to know, there is any feasibility to operate the PCV in auto without instrument air so that we can run the GTG?

Is any feasibility to change the control valve by operating itself by fluid instead of instrument air pressure?

I have checked 3-4 sites but all are having PCV is operated by instrument air only. Please guide me if feasibility is available and what have to do.

 

VKGUPTA,

I took a few minutes and read your past posts. Seems like a lot of problems--and we've had virtually nothing from you in the way of feedback about any of them to know of the information that's been provided has been helpful, or not.

It's suggested you contact a valve manufacturer representative in your area (industrial valves) and explain your situation. A knowledgeable representative can make a recommendation which could help to resolve your problem--and in the process makes a sale for the company he works for as well as the valve manufacturer he represents. Many times they have some very good recommendations--and a really good representative will refer you to someone else if they don't have the proper equipment.

Many gas fuel pressure regulating valves are operated by gas fuel pressure. <b>HOWEVER</b>, before you rush out and reconnect gas fuel in place of air be aware that the actuator must be rated for gas fuel service--and most actuators are not. Perhaps IL has an actuator which can operate off gas fuel pressure. Or, perhaps, some other valve manufacturer does.

But, the most disconcerting part of your post is the minimal emphasis on the ESD (Emergency Shut-Down) valve which requires air pressure to operate. It would seem that this is just as important as the gas fuel pressure regulator....

It seems that the air compressor problems are insurmountable (and that would be extremely unusual). Even purchasing a new air compressor, with a receiver tank, and dedicating it to these two critical applications would seem to be as inexpensive as sourcing a new pressure regulating valve and ESD valve, or new actuators for the existing valves (gas-operated actuators to replace the air-operated actuators).

Many people read these posts and learn a lot from them--especially when those asking for assistance post feedback to let others (and the respondent(s)) know if the information provided was helpful or not. "Feedback is the most important contribution!"(c) here at control.com and it's what makes this forum so valuable to the many people who read and follow the posts and responses here. While your site seems to be experiencing a higher than usual number of problems many other sites have similar problems and people can benefit from the feedback you provide about the information you've received from your posts for help and guidance here on control.com.

Looking forward to hearing about your resolution to the issues you've been experiencing at your site with your BHEL-packaged Frame <b><i>5</i></b> GE-design heavy duty gas turbine-generator.