Sludge as a relinquishing catalyst in Co-Pyrolysis with palm Empty Fruit Bunch Fiber

Abstract

Bio-oil from the fast pyrolysis of biomass has the potential to be an effective and reliable renewable energy source. A common issue faced is the high acidity of bio-oil, which obstructs bio-oil storage and processing. This study utilized fast co-pyrolysis of oil palm Empty Fruit Bunch Fiber (EFBF) with Palm Oil Sludge (sludge) at different ratios (10, 20, 35 and 50 wt.% sludge with EFBF) to produce bio-oil with higher pH. The sludge with high ash content acted as a catalyst for esterification at higher percentages. Bio-oil yields decreased from 41.2 ± 3.4 wt.% (for EFBF) to 28.8 ± 1.4 wt.% (for sludge) as the sludge percentage increased from 0 to 100%. The catalytic effect posed by mineral metals in sludge led to a negative synergistic effect in terms of yields of bio-oil. Physicochemical properties of bio-oils were analyzed and compared to ASTM standards. An increase in pH value (7.2 ± 0.0) was achieved for bio-oil that was derived from the blend with 50 wt.% sludge. However, the bio-oil yield was compromised. Based on the yield and physical properties of bio-oil, the blend with 35 wt.% of sludge was selected as the desired ratio to further study the co-pyrolysis of EFBF and sludge. A bio-oil with pH 4.5 was successfully produced in one of the most economical method.