Power Boiler Continuous Blowdown Control

You are aware of the cost difference. The big question is lifetime and operating reliability. The process certainly does not require that the blow down be a continuous process. Before you can really compare the two methods, you have to think about how few on off cycles per hour are really needed. The lower this number can be, the better the reliability for the ball valve. You may well be able to substitute a two threshold operation for a time proportional control.

The control valve in a throttling condition would more prone to plugging with particulate, especially if this is a 600# class boiler with a hot process zeolite softeners or similar equipment.

Are your multiple blowdowns all piped to this po>Curtis wrote:

If you are considering a ball valve with restriction plates downstream take a look at Valvetechnologies

We use a normal control valve and a PID controller witch get it´s setpoint from a ratiostation connected to the feedwaterflow. Works fine for us.

"Curtis" skrev i meddelandet news: snipped-for-privacy@posting.google.com...

Yeah, I thought about that, and then trimming the ratio station with a Conductivity controller, but I think that might be "over-instrumentating" the control for a little 115,000 pound boiler.

By the way, what type of valve do you use?

Thanks

Curtis

We use a Neles segment ball valve, DN50 (2") PN100. The ratio between feedwaterflow and blowdown are 4% the lab takes a sample once a day just to make sure everythings ok. "Curtis" skrev i meddelandet news: snipped-for-privacy@posting.google.com...