Chemical from agricultural and industrial waste. Pyrolysis products from residues of palm oil industry

Abstract

Palmkernel shell (PKS) and empty fruit bunches, both raw (EFB-R) and pre-treated bymeans of autoclaving (EFB-A) and microwave (EFB-M), were pyrolyzed in a fixedbed stainless steel reactor at 550 °C. The yield of the water-solubleliquid fraction (pyroligneousacid, PA) in the pyrolysis of PKS was 26 %wt. (dry basis), and in the range of16-46 %wt. when different EFB were used. The yield of insoluble liquid fraction(bio-oil, BO) was 9.1 %wt. for PKS and up to 25 %wt. in the case of EFB. Liquidand gaseous products were analysed by conventional capillary gaschromatography. The PA from the PKS had 30 %wt. of total phenolic compounds (upto 24 %wt. phenol) and 46 %wt. acetic acid. On the other hand, the bio-oil fromPKS had 43%wt. of total phenolic compounds (up to 26 %wt. phenol) and 17 %wt.acetic acid. ThePA from EFB contained mainly acetic acid (65.5 %wt.), furfural (7.7 %wt.), methanol(8.0 %wt.) and phenol (15.2 %wt.). When EFB was pre-treated, the concentrationof acetic acid in PA decreased dramatically, while the concentration of furfuralincreased up to ten times, this effect being more noticeable in the case ofmicrowave pretreatment. The yields of by-products were of significance in all cases (13-23 %wt.of gases and 33-52 %wt. of char). These results show that the liquid productsobtained from the pyrolysis of palm oil industrial wastes could be used inorder to obtain chemical raw materials of worldwide extended use, while theby-products (gases and char) can be used as renewable energy sources.