Utilization of glycerol as a bio-fuel additive through acetylation reaction using Ni/Zeolite catalyst in fixed bed reactor

Glycerol is a byproduct of biodiesel produced from 10% of a total biodiesel volume. An attempt to process glycerol into another product needs to be done in order to increase the economic value of glycerol. One of the methods is to convert it into triacetin through the esterification reaction of glycerol and acetic acid using a heterogeneous catalyst Ni/Zeolite. Triacetin can be applied as a fuel additive to reduce knocking in machinery. This research aims to evaluate the effect of glycerol mole to acetic acid, the effect of feed flow rate on glycerol conversion in fixed bed reactor, and the effect of reaction products addition to the increase of fuel octane number. The temperature used for esterification reaction of glycerol triacetin was 100˚C. The mole ratio of glycerol and acetic acid used was 1:3; 1:5; 1:7; 1: 9, and feed flow rate used in fixed bed reactor was 40; 60; 80; 100 mL/minute. The experimental results showed that the highest glycerol conversion occurred at a feed flow rate of 40 mL/min, with a ratio of glycerol to acetic acid 1:9 which resulted in a glycerol conversion of 72.05%. To evaluate the performance of the acetylation reaction, the product was added to commercial fuels (Premium, Pertalite and Pertamax) at various percentages and resulted in an increase in the octane number of commercial fuels. So it can be concluded that the product of the acetylation reaction can function as a bio additive. The highest octane number increase was obtained by adding 8% product to Pertamax fuel with an 8.5% increase in octane number from the initial value of 93 to 101.