Mathematical modeling and numerical simulation of low-emission natural gas combustion

 

B. Soroka, Prof., Dr.Sc.(Eng.), Gas Institute of NASU, Kiev, Ukraine, M.Khinkis, H. Abbasi, Gas Technology Institute (GTI), Des Plaines, IL, USA

 

The mathematical model and computer code of low-emission combustion unit operation were developed basing upon Forced Internal Recirculation Burner (FIRB) concept. The design of FIRB was proposed and patented by IGT (now - GTI) founding on combination of some NOx reduction methods particularly due to two-stage natural gas combustion and recirculation of partially burnt combustion products.

Numerical simulation procedure was carried out by Gas Institute, NASU. The results of computations are presented for the FIRB design with peripheral primary combustion chamber. Each of two main FIRB operational characteristics: primary air excess factor b_p and recirculation ratio r –were tested in combination with other operational and design parameters making allowance for influence on [NOx] value at the FIRB’s exit.

The value of optimal b_p from minimum [NOx] value standpoint falls usually on b_p,opt =0.75…0.80. Increased recirculation ratio value in some cases {b_p>b_p,opt) lowers [NOx] by increase of recirculation ratio whereas in other cases (b_p< b_p,opt) higher r value provides rise of [NOx] at the exit of FIRB.