Friday, April 28, 2006
Ugly start up
The picture above is the control room, where my daughter is minding operation of the plant. Typical operator attentiveness :) Actually a few seconds after I took this picture she shut off our gate security computer and camera system, hahaha
The control room felt more like misson control during Apollo 13 yesterday. The startup left our entire crew feeling wrung out and exhausted.
The fuel gas heater control loop wasn't working well at all. Hot water from the boiler flows through it to pre-heat the natural gas entering the gas turbines. These gas turbines require heated fuel to run above about 20% load. The gas turbines are also not emissions-compliant until they get to about 40% load.
So connecting the dots, we needed heated fuel to be emissions compliant, but heated fuel was an on-and-off thing. We'd get emission compliant, then something would go wrong with the water flow through the fuel heater. Gas would overheat and the turbine would runback to minimum load, out of emission compliance. What a pain in the neck.
We did learn something though... If you blast enough ammonia into the boiler, it doesn't matter if you are in emission compliant burn mode or not - you can still knock the NOx levels down to permit limits. We didn't violate our air permit limits, as I would have thought.
Meanwhile, the steam turbine was experiencing its own set of difficulties. It kept tripping every time I tried to place it in pressure control mode - so eventually I gave up. I brought it up in manual, and it remained in manual. Each time it tripped, we had enormous boiler pressure swings. For one reason or another the steam bypasses wouldn't open to allow steam to bypass the turbine and go into the condenser, so it went out the vents. And so we very nearly lost the entire plant on low boiler levels as the steam escaped the system.
It was a nerve-wracking 4 hours, but eventually we experienced and overcame all the problems that cropped up, without violating our permits or losing too much revenue replacing electricity that had been sold. Afterwards I wrote work orders on all the messed up stuff and then revised the start-up procedure for cycling - something we will likely be doing every night for the next couple of months until energy prices pick up as the weather gets hot.
Anyhow, I was totally mentally wrung out and had *no* problem falling asleep at the end of the day... unusual considering my typical insomnia.
Posted by Mark at 2:43 PM