Park JW  Lu HV  Linh LM  Tran QK  Kim SS  Kim JS

Vol. 25,  No. 2, pp. 168-176, Jun.  2019
10.7464/ksct.2019.25.2.166

Spent coffee waste Upgrading bio-oil Hydrodeoxygenation HZMS-5 Dolomite

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Spent coffee is one of biomass sources to be converted into bio-oil. However, the bio-oil should be further upgraded to achieve a higher quality bio-oil because of its high oxygen content. Deoxygenation under hydrotreating using different catalysts (catalytic hydrodeoxygenation; HDO) is considered as one of the promising methods for upgrading bio-oil from pyrolysis by removal of O-containing groups. In this study, the HDO of spent coffee bio-oil, which was collected from fast pyrolysis of spent coffee (460 ℃, 2.0 × Umf), was carried out in an autoclave. The product yields were 72.16 ~ 96.76 wt% of bio-oil, 0 ~ 18.59 wt% of char, and 3.24 ~ 9.25 wt% of gas obtained in 30 min at temperatures between 250 ℃ and 350 ℃ and pressure in the range of 3 to 9 bar. The highest yield of bio-oil of 97.13% was achieved at 250 ℃ and 3 bar, with high selectivity of D-Allose. The carbon number distribution of the bio-oil was analyzed based on the concept of simulated distillation. The C12 ~ C14 fraction increased from 22.98 wt% to 27.30 wt%, whereas the C19 ~ C26 fraction decreased from 24.74 wt% to 17.18 wt% with increasing reaction time. Bio-oil yields were slightly decreased when the HZSM-5 catalyst and dolomite were used. The selectivity of CO was increased at the HZSM-5 catalyst and decreased at the dolomite.