Evaluation of Separate and Simultaneous Kinetic Parameters for Levulinic Acid and Furfural Production from Pretreated Palm Oil Empty Fruit Bunches

Misri Gozan,Young Je Yoo,Dewi Tristantini,Jabosar Ronggur Hamonangan Panjaitan,Rizal Alamsyah

doi:10.1155/2018/1920180

Abstract

Palm oil empty fruit bunches (POEFBs) can be converted into levulinic acid (LA) and furfural, which are among the top building-block chemicals. The purpose of this study was to investigate separate and simultaneous kinetic model parameters for LA and furfural production from POEFBs, which were pretreated by soaking in aqueous ammonia (SAA). The highest LA yield, which was obtained at a reaction temperature of 170°C after 90 min in an acidic solution with a concentration of 1 M, was 52.1 mol%. The highest furfural yield was 27.94 mol%, which was obtained at a reaction temperature of 170°C after 20 min in an acidic solution with a concentration of 0.5 M. SAA pretreatment affected activation energy in glucose degradation reactions and favoured direct conversion of hemicellulose to furfural. The activation energy of LA production (EakHMF) increases with higher acid catalyst concentration, and the activation energy of furfural production (EakXYN) decreases with higher acid concentration. These trends in the activation energy occurred in both separate and simultaneous kinetic models. Simultaneous kinetic model is better to calculate kinetic parameters of LA and furfural production than separate kinetic models because the simultaneous kinetic model had a lower sum of square error (SSE) when estimating kinetic parameters.

Highlights

Sample compositional analysis of Palm oil empty fruit bunches (POEFBs) before and after the ammonia pretreatment was determined by referring to the method of the National Renewable Energy Laboratory (NREL) [28, 29], and scanning electron microscopy (SEM) of POEFBs was performed to determine the condition of the fibres. e liquid product concentration from kinetic experiments such as glucose, xylose, HMF, furfural, and levulinic acid (LA) was analysed using highperformance liquid chromatography (HPLC), with an Aminex HPX-87H ion exclusion column (Bio-Rad, Life Science Group Hercules, CA). e eluent was 0.006 N of H2SO4, and the ow rate was 0.6 ml/min
Separate kinetic evaluation assumed that there is no interference between LA and furfural kinetic reaction, so the kinetic parameter calculation of LA and furfural would be done in a separate kinetic model
The simultaneous kinetic evaluation calculated LA and furfural kinetic reaction in one kinetic model. e e ects of other components in POEFBs such as lignin and ash were negligible from LA and furfural kinetic models, and kinetic parameter calculation since ammonia pretreatment was done before kinetic experiments

Summary

Materials and Methods

The simultaneous kinetic evaluation calculated LA and furfural kinetic reaction in one kinetic model. E e ects of other components in POEFBs such as lignin and ash were negligible from LA and furfural kinetic models, and kinetic parameter calculation since ammonia pretreatment was done before kinetic experiments. Reaction rate constants were optimized by minimizing errors between the experimental data, such as the concentrations of glucose, xylose, HMF, furfural, and LA at various temperatures and concentrations of acid catalyst with kinetic models. E yield of furfural from the POEFBs on a molar basis (YF) was defined as the ratio of the furfural in the acid hydrolysis product (Cfurfural) to the initial C5 sugar concentration in the POEFBs (C5): YF(mol/mol)%. E calculation of acid reaction order was counted based on (8) from the average value of kinetic experiment temperature

Results and Discussion

Kinetic Parameter Estimation for Simultaneous Kinetic

Evaluation of the Separate Kinetic Parameters of LA and Furfural Production