dc.description.abstract | ABSTRACT
In this thesis, palm kernel shell (PKS) biomass are pyrolyzed in a fast pyrolysis system using
fluidized bed reactor and ceramic balls as fluidizing medium, with CO2 as fluidization gas. The
purpose of this research is to find the effect of operating parameters, such as reactor temperature (350º
- 550ºC), fluidizing gas flow rate (5-15 liter/min) and heating rates (1, 5, 10 K/min) on the yield of
each pyrolysis product (bio-oils, gas, and char). The composition of PKS biomass and their product are
investigated according to ASTM (American Society for Testing and Materials) standard methods. The
result shows that the maximum bio-oil yield is 20.4 wt.%, occurred at 500ºC and the flow rate of CO2
is 10 liter/min, the other product are char with 36.0 wt.% and gas with 43.6 wt.%. Char decreases
with increasing reactor temperature and CO2 flow rate. A opposite, the gas product increases with
increasing reactor temperature and CO2 flow rate above 10 liter/min. From TG (thermogravimetry) and
DTG (differential thermogravimetry) analysis, the weight loss are generally divided into 3 parts. First,
occurred from 100ºC to 220ºC, presented the moisture and extractive evaporations. The second weight
loss occurred at 240ºC - 400ºC, the thermal decomposition of cellulose and hemicellulose and the
third, the weight loss above 400ºC until 900ºC is mainly due to the decomposition of lignin. The DTG
curves have two peaks. The first peak is assigned to devolatilization of hemicellulose, while the second
peak is cellulose. The effects of the heating rate on the DTG curve and maximum decomposition rate
are investigated. At higher heating rates, individual conversions are reached at higher temperatures.
For the heating rate of 1 K/min, the first and second peak occurred at 280 ºC and 380ºC. For 5 K/min,
they occurred at 305 ºC and 390 ºC. They occurred at 310 ºC and 405 ºC for 10 K/min. The maximum
of the decomposition rate is also slightly shifted towards higher temperature. CHNO content of bio oils
are 67.70 wt.%, 9.70 wt.%, 0.90 wt.%, and 21.70 wt.%, respectively. Bio-char have high carbon
content, around 62.87 wt.%, other elemental compositions are 2.54 wt.% of hydrogen, nitrogen with
0.56 wt.%, 0.01 wt.% for sulfur, and oxygen with 10.80 wt.%. Proximate analysis of PKS bio char gets
23.18 wt.% of ash, 3.30 wt.% of moisture, also HHV, volatile matter, and fixed carbon with 23.56
MJ/kg, 17.86 wt.%, and 58.96 wt.%, respectively. When using CO2 utilized as fluidization gas, the gas
product has compositions similar to previous study, and consists mostly of CO2 (Over 50 vol.%),
followed by CO, and little amount of CH4 and H2.
Keywords: Biomass, palm kernel shell, fast pyrolysis, bio-oil | en_US |