Health & Environmental Research Online (HERO)


Print Feedback Export to File
4278587 
Journal Article 
Acetylene Pyrolysis in Tubular Reactor 
Rokstad, OA; Lindvaag, OA; Holmen, A 
2014 
Yes 
International Journal of Chemical Kinetics
ISSN: 0538-8066
EISSN: 1097-4601 
46 
2 
104-115 
English 
WOS:000328635400002 
Pyrolysis of acetylene was investigated in a tubular reactor of graphite with an internal lining of alumina. The temperature range was 850-1650 degrees C, and the pressure was about 0.133 bar (100 Torr). Pure acetylene and acetylene diluted with argon or hydrogen were used as feed. Carbon and hydrogen are the main products from acetylene pyrolysis particularly at higher conversion. At lower conversion of acetylene, other gas products were formed; the amount of these depended on temperature, dilution, and conversion. Benzene and vinyl acetylene are the main gas products from pyrolysis of pure acetylene below 1000 degrees C and at low conversion. Diacetylene increases with increasing temperature. Dilution with hydrogen changes the composition of the gas product, decreases the selectivity of vinyl acetylene and benzene, and increases the formation of methane and ethylene. Gas-phase equilibrium may be approached between some components. The conversion of acetylene with argon dilution and low conversion was found to be of secondorder. Pyrolysis of pure acetylene at lower temperature and low conversion gave the rate constant k= 3.1 x 10(9) exp(-34.8/RT)Lmol(-1)s(-1) with an activation energy of 34.8 kcal mol(-1). The initial reaction at 864 degrees C is a molecular formation of vinyl acetylene. The initial activation of acetylene in gas phase seems to be rate determining and of second order in acetylene. Decomposition of acetylene can take place both homogeneously and heterogeneously. Above a critical partial pressure of acetylene, the decomposition is apparently explosive with instant plugging of the reactor with carbon. (C) 2013 Wiley Periodicals, Inc.