Contact us
 |
[email protected] |
 |
3275638434 |
 |
 |
| Paper Publishing WeChat |
Useful Links
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License
Article
Author(s)
Haruki Tani1, 2 and Kaoru Fujimoto1, 3
Full-Text PDF
XML 1195 Views
DOI:10.17265/2162-5263/2017.07.002
Affiliation(s)
1. Department of Chemical Processes and Environments, Faculty of Environmental Engineering, The University of Kitakyushu, Kitakyushu 8080135, Japan
2. Department of Chemical System Engineering, Graduate School of Engineering, Nagoya University, Nagoya 4648603, Japan
3. HiCOP Laboratory Association, Fukuoka, Kitakyushu 8080135, Japan
ABSTRACT
The cracking of polyolefins, especially polyethylene in the molten state
was effectively catalyzed by the powdery spent FCC (Fluid Catalytic Cracking) catalyst which was
dispersed in it. The activation energy of the catalytic cracking of
polyethylene was about 74 kJ/mol. The cracked product was naphtha and middle
distillate as the major product and gaseous hydrocarbon (C1-C4)
as the minor product while little heavy oil was produced. The chemical
compositions of the product were: aromatic
hydrocarbons, isoparaffins and branched olefins, whereas that of the
non-catalyzed products were: n-olefins and
n-paraffins with minor amount of dienes with increasing the process time. Additionally, the product pattern
shifted from naphtha rich product to kerosene and gas-oil rich product. However, any catalytic
product showed low fluid point (< -10 oC), while that of the
non-catalyzed product was as high as 40 oC. Catalyst could
process, more than 100 times by weight of polyethylene with fairly small amount
(~ 30 wt%) of coke deposition. Spent catalyst gave higher hydrocarbons while
fresh catalyst gave gaseous product as the major product. Other polyolefins such
as polypropylene and polystyrene were tested on same catalyst to show that
their reactivity is higher than that of polyethylene and
gave the aliphatic products, alkyl benzenes and C6-C9 iso-paraffins as the major product. Product pattern of the cracked product
suggested that the reaction proceeded via the primary reactions making
paraffins and olefins which were followed by the isomerization, secondary
cracking, aromatization and hydrogen transfer which based on the carbenium ion
mechanism.
KEYWORDS
Polyolefin, spent FCC (Fluid Catalytic Cracking) catalyst, catalytic cracking, carbenium ion mechanism, superior stability.
Cite this paper
References