In my plant we have DLN Type GTG FRAME 9E Mark V, but we can't go to Premix Mode. then I don't know which mode is better work? Primary mode or secondary mode?

You can say to me If we have spread during transferring and a lot of coke around primary nozzle, may be we can't go to premix mode?

In another plant there is the same unit. this unit after HGP, the unit goes to premix mode. after that this unit work at primary mode for a month but after that this unit can't go to Premix mode.

<b>Moderator's note:</b> This question was originally asked as part of thread http://www.control.com/thread/1399913837#1399991407, but was made it's own thread.

 

It's very difficult to comment specifically, but based on the information provided something is amiss and should be investigated and resolved.

Operation in either "primary" or "secondary" (Lean-Lean) modes for extended periods of time is not recommended. As is prolonged operation in Extended Lean-Lean. DLN-I combustors are designed to be operated on Premix Steady-state and all other combustion modes are intended to be "transit" modes into or out of Premix--which is the low emissions mode which is the entire reason for DLN combustors.

DLN combustors are not without their quirks, and do require clean fuel and proper operation and maintenance.

 

Generally in using a DLN combustion system, it is not advised to operate in the Lean Lean Extended mode. The primary purpose of the DLN is to reduce emission as low as possible. Operating on Lean Lean extended mode might rupture the combustion nozzles and also lead to the emission of of more Cox, Sox, and Cox.