Two-mixture-fraction in Non-Premixed Combustion Model
 

Hello everybody,
I want to simulate coal gasification by using Non-Premixed Combustion and DPM in 3D Model. I've tried use single-mixture, but char conversion only 20%. In the literature, Fluent User's Guide, using two-mixture-fraction more accurate than single-mixture. So, I want to use two-mixture-fraction. But, I can't create PDF table and appeared "Calculation aborted due to critical error". Why it happened?
Can you tell me about the constraints for using two-mixture-fraction?

Anyone have paper/journal/tutorial guide which contains solution of coal gasification by using Non-Premixed model?

Thankyou