Evaluation of Ignition Quality of LPG with Cetane Number Improver 2002-01-0870

The objective of this study is to improve the ignition quality of LPG (liquefied petroleum gas) in order to utilize LPG as a diesel fuel. First, the relationship between the cetane numbers and ignition delay periods of primary standard fuels (mixtures of n-cetane and heptamethylnonane) and diesel fuels were investigated by measuring the ignition delay periods using a constant volume combustion chamber. As a result, it was found that a good relationship between the cetane numbers and ignition delay periods could be obtained for a 550°C combustion chamber temperature and 4MPa pressure. Also, the cetane number estimation equation was established using the ignition delay data of n-paraffins. Next, the constant volume combustion chamber was modified to evaluate the ignition delay period of LPG with a cetane number improver, and these cetane numbers were then estimated. The estimated cetane numbers of the LPG with a 15 wt % cetane number improver were more than 50 suggesting the possibility of utilizing LPG as a diesel fuel. Furthermore, the ignition quality of LPG with n-paraffins and a cetane number improver were evaluated. As a result, the ignition quality of LPG with 30wt% n-paraffin and 1wt% di-tert-butyl peroxide was equivalent to that of commercial diesel fuels. This result suggests that it is possible to develop an LPG-based diesel fuel containing a low cetane number improver.