scholarly journals Experimental study on the effect of hydrogen addition on methane/ethylene diffusion flame soot formation based on light extinction measurement

2021 ◽  
Vol 7 ◽  
pp. 673-683
Author(s):  
Yuhan Zhu ◽  
Jiajia Wu ◽  
Bencheng Zhu ◽  
Yang Wang ◽  
Mingyan Gu
1999 ◽  
Vol 117 (1-2) ◽  
pp. 117-139 ◽  
Author(s):  
M SMOOKE ◽  
C MCENALLY ◽  
L PFEFFERLE ◽  
R HALL ◽  
M COLKET

2006 ◽  
Vol 145 (1-2) ◽  
pp. 324-338 ◽  
Author(s):  
Hongsheng Guo ◽  
Fengshan Liu ◽  
Gregory J. Smallwood ◽  
Ömer L. Gülder

Author(s):  
Fengshan Liu ◽  
Francesca Migliorini ◽  
Francesco Cignoli ◽  
Silvana De Iuliis ◽  
Giorgio Zizak

Numerical and experimental studies were conducted to investigate the effects of hydrogen and helium addition to fuel on soot formation in atmospheric axisymmetric coflow laminar methane-air diffusion flame. Soot temperature and volume fraction distributions were measured using a two-dimensional two-color technique. Numerically the conservation equations of mass, momentum, energy, and species in the limit of low-Mach number were solved. Detailed gas-phase chemistry and thermal and transport properties were accounted for. Radiative heat transfer by CO, CO2, H2O, and soot was calculated using the discrete-ordinates method with the radiative properties of the mixture obtained from a wide-band model. Soot was modeled using a two-equation semi-empirical model in which the mechanisms for inception and surface growth are assumed to be PAH coagulation and H-abstraction acetylene addition. Both experimental and numerical results show that helium addition is more efficient than hydrogen addition in reducing soot formation in the methane flame. These results are different from the previous investigations in ethylene flames where the hydrogen addition was found to be more effective in reducing soot formation than helium addition due to the additional chemical suppression of hydrogen on soot. It is suggested here that hydrogen chemically enhances soot formation when added to methane.


Author(s):  
Hongsheng Guo ◽  
Fengshan Liu ◽  
Gregory J. Smallwood

The influence of hydrogen addition to the fuel on soot formation in an ethylene/oxygen/nitrogen diffusion flame was numerically studied by simulation of three counterflow laminar diffusion flames at atmosphere pressure. The fuel mixtures for the three flames are pure ethylene, ethylene/hydrogen and ethylene/helium, respectively, while the oxidant is a mixture of oxygen and nitrogen. A detailed gas phase reaction mechanism including species up to benzene and complex thermal and transport properties were used. The soot inception and surface growth rates were, respectively, calculated based on benzene and HACA (H-abstraction and C2H2-addition) mechanisms. The predicted results for the three flames were compared and analyzed. It is indicated that although the addition of either hydrogen or helium to the fuel can reduce the soot volume fraction, the addition of hydrogen is more efficient. While the addition of helium reduces soot formation only through dilution, the addition of hydrogen suppresses soot formation through both dilution and chemical reaction effects. This conclusion is qualitatively consistent with available experiments. The simulations revel that the chemically inhibiting effect is caused by the decrease of hydrogen atom concentration in soot formation region, due to the displacement of the primary reaction zone, when hydrogen is added to the fuel.


Author(s):  
Noriaki Nakatsuka ◽  
Yasushi Imoto ◽  
Jun Hayashi ◽  
Miki Taniguchi ◽  
Kenichi Sasauchi ◽  
...  

For the electric power generation by the woody biomass gasification, tar is incidentally formed at the same time. Tar means a compound of many kinds of aromatic hydrocarbons and causes some troubles, for example, clogging pipes when it is cooled and condensed before being supplied to the gas engine for electric power generation. One way for reducing tar is oxidative and thermal cracking by partial combustion of the producer gas in the gas reformer that is a stage subsequent to the biomass gasifier. During the partial combustion process of the producer gas, inverse diffusion flame is formed when oxidizer is supplied to producer gas. Cracking and polymerization of tar occur simultaneously at the proximity of the inverse diffusion flame. This polymerization of tar into soot is, however, a significant problem in the gas reformer. Experimental study was performed to clarify the effect of hydrogen concentration in the combustion region on soot formation and the growth of polycyclic aromatic hydrocarbons (PAHs) that is precursor of soot. In the present study, hydrogen concentration at the proximity of the inverse diffusion flame was controlled by the small amount of hydrogen addition to the oxidizer. The main results were as follows. Soot formation was suppressed by the small amount of hydrogen addition (approximately 0.5% to the total enthalpy of the producer gas). The suppression of soot formation was caused by higher concentration of hydrogen at the proximity of the combustion region since the aromatic radicals were neutralized before they could combine together or with acetylene. Carbon yield was increased with the increase in the amount of hydrogen added to the oxidizer as carbon content in the undetectable components by the integrated gas chromatograph such as the soot was decreased. In addition, the increase of carbon yield resulted mainly from the increase in carbon monoxide stemmed from reforming of high-boiling components such as soot.


1998 ◽  
Vol 27 (1) ◽  
pp. 1497-1505 ◽  
Author(s):  
C.S. McEnally ◽  
A.M. Schaffer ◽  
M.B. Long ◽  
L.D. Pfefferle ◽  
M.D. Smooke ◽  
...  

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