Nanostructured materials as catalysts for the production of gasoline from used palm oil and crude palm oil:
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Date
2007
Authors
Ahmad Shah, Noor Aisyah
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Abstract
The objective of this research was to develop an efficient cracking catalyst with
good hydrothermal stability, reusability, low deactivation rate and minimum side
products with high selectivity towards gasoline fraction yield. In this research, the
catalytic process for the production of gasoline from crude palm oil (CPO) and used
palm oil (UPO) was studied at atmospheric pressure, temperature of 723 K, weight
hourly space velocity (WHSV) of 2.5 h-1 and crude/used palm oil to catalyst ratio of 8 in
a fixed bed micro-reactor.
Six different types of composite catalysts namely; HZSM-5/alumina (CZA), HBeta/
silica-alumina (CBS), Al-MCM-41/alumina (CMA), Al-MCM-41/silica-alumina
(CMS), Al-SBA-15/alumina (CSA) and Al-SBA-15/silica-alumina (CSS) were
synthesized and tested as cracking catalysts. The composite CZA and CBS were
characterized for their surface area, adsorption-desorption isotherm, pore size
distribution, crystallinity, acidity and surface morphology. The composites CMA, CSA,
CMS and CSS were characterized for their crystallinity, acidity and surface
morphology.
HZSM-5 gave 98.5 wt% UPO conversion with 45.2 wt% yield of gasoline
fraction and 25.9 wt% gaseous products. Composite CZA35 gave 97 wt% UPO
conversion, 47 wt% yield of gasoline fraction and 19.7 wt% gaseous products as
compared to HZSM-5. The alumina coating increased the average pore size (APS) of
the mesopores and reduced the acidity of composite catalyst. Steam treated HZSM-5
and CZA35 showed comparable activity as the fresh catalysts. St-ZSM5 gave 93.5 wt%
UPO conversion with 46 wt% yield of gasoline fraction and UPO conversion was 92.3
wt% with 46.3 wt% yield of gasoline fraction over St-CZA35. The reduction in the
surface area of St-CZA35 was lower as compared to St-ZSM5. The aromatics (BTX)
present in the organic liquid product (OLP) were reduced from 33.9 wt% obtained with
fresh CZA35 to 17.9 wt% over St-CZA35.
Composite CBS25 gave comparable gasoline fraction yield with 62.9 wt% CPO
conversion as compared to 74.5 wt% CPO conversion over H-Beta. Its activity was
improved after steam treatment with increase in CPO conversion to 74.7 wt% with
gasoline fraction yield of 31.8 wt%. H-Beta activity dropped after steam treatment with
drop in conversion from 74.5 wt% to 65.5 wt% and gasoline fraction yield from 26 wt%
to 23.8 wt%. The coating of silica-alumina helped to increase the cracking activity and
hydrothermal stability of the composite due to change in the surface morphology.
The coating of alumina improved Al-MCM-41 hydrothermal stability. St-CMA25
gave 62 wt% CPO conversion with 19.7 wt% gasoline fraction yield, higher than that
obtained over St-AlMCM-41 (60.5 wt% conversion with 13.1 wt% gasoline fraction
yield). The composites CSA, CMS and CSS gave low cracking activity due to changes
in the surface morphology as observed from SEM analysis. Comparing the
performances of all synthesized composites, CZA35 was found to be best cracking
catalyst.
The deactivation of catalysts was studied by obtaining time on stream data with
palm oil to catalyst ratio in the range of 8 to 16. Composites with alumina, CZA and
CMA showed lower deactivation as compared to HZSM-5 and Al-MCM-41 catalysts.
The deactivation data were fitted using suitable activity model and deactivation
parameters were obtained.
Description
Master
Keywords
Science Physic , Nanostructured materials , catalysts , production of gasoline , palm oil , crude palm oil