Coupling of thermal cracking with noncatalytic oxidative conversion of Ethane to Ethylene

Simultaneous thermal cracking and oxidation of propane to propylene and ethylene

“…The observed influence of oxygen in the feed on the thermal cracking of propane is quite similar to that observed earlier (Choudhary and Mulla, 1997) for the cracking of ethane in the presence of 0,. However, the enhancement in the rate of thermal cracking due to the presence of oxygen for the propane cracking is higher than that for the ethane cracking, particularly at higher temperatures.…”

“…Our earlier studies (Choudhary and Mulla, 1997) indicated that the pro-cess performance and energy requirement in the thermal cracking of ethane to ethylene can be improved and most of the limitations of the thermal cracking process can be overcome by carrying out the ethane cracking in the presence of limited oxygen. Because of the presence of limited oxygen, both the exothermic oxidative conversion and endothermic thermal cracking of ethane occur simultaneously, making this process highly energy efficient, with a drastic reduction in external energy requirement and coke formation.…”

Non-catalytic pyrolysis of ethane to ethylene in the presence of CO2 with or without limited O2

“…Earlier studies on the oxy cracking of ethane in the presence of limited O 2 have indicated that the formation of CO 2 as compared to CO in the process is very small. 2 The results in figure 5 show that, as in the presence of CO 2 alone, the ethane conversion increases increasing the CO 2 /C 2 H 6 ratio. However, unlike in the presence of CO 2 alone, ethylene selectivity also increases significantly, the increase being almost linear.…”

“…This observation is quite similar to that reported by us earlier in case of non-catalytic ethane or propane cracking in presence of limited O 2 . 2,4 It appears that ethane is activated by CO 2 at the high reaction temperature (850°C), enhancing the rate of C-C bond cleavage and forming two methyl radicals, which are the primary products formed in the thermal cracking of ethane.…”

“…In order to overcome these problems we have suggested earlier to carry out ethane and propane thermal cracking reactions in the presence of limited oxygen. [2][3][4] By carrying out the thermal cracking of ethane, propane or C 2 -C 4 hydrocarbons from natural gas in the presence of steam and limited oxygen, not only the energy requirement is drasti-cally reduced but also the coke formation is eliminated or drastically reduced and also the hydrocarbon conversion much above 70% could be obtained. Also in the presence of oxygen, the thermal cracking of ethane/propane is enhanced because of the change in the hydrocarbon activation mechanism and hence the oxy cracking process could be carried out at a much lower temperature and/or contact time than that required for achieving the same conversion in the thermal cracking process.…”