Zeolit Pt/H-β som isomeriseringskatalysator för biodiesel - Chalmers ...

Abstract
Preem refinery in Gothenburg is currently manufacturing biofuel by adding renewable fuel
compounds to fossil fuel. The renewable fuel compounds consist of linear n-alkanes, which
are easilly crystallized and thus impairing the cold properties of the fuel. Therefore, a smaller
amount of renewable compounds can be added during winter. It is desirable to enable an
increased composition of renewable compounds in biofuel which can be achieved by catalytic
isomerization and thereby branching linear n-alknes.
Consequently a catalyst mass is constructed consisting of zeolite H-β, catalyst support and
binder and loaded with 1.14 weight percent platinum. The catalyst is placed in a pilot plant
in order to study the reaction of a diesel flow enriched with 10 weight percent hexadecane
over the reactor whilst varying temperature and LHSV, which denotes the fraction between
volumetric flow and catalytic volume. The temperature is varied between 210 ◦ C and 240 ◦ C
and LHSV is varied between 0.6 m 3 /(m 3 cat · hour) and 1.46 m 3 /(m 3 cat · hour). The study uses
hexadecane in order to imitate the linear n-alkane components of renewable fuel.
Samples are extracted from the pilot plant and analyzed with gas chromatography and distillation
after which the densities and cloud points are investigated. The cloud point indicates
at what temperature the fuel starts to crystallize. The results determined whether the cold
properties have been improved and what reactions take place in the reactor. Also, after being
used in the reactor, a sample of catalyst is investigated on the degree of coke formation, which
deactivetes the catalyst.
The results show cloud points below -22 ◦ C for each temperature and LHSV setting. In
addition, the results indicate considerable cracking at some variable settings, which entails loss
of product. At 210 ◦ C and LHSV 1,46 m 3 /(m 3 cat · hour) a low cloud point and little cracking
is obtained. This indicates that isomerization actually takes place and that those settings
are suitable for production. Withal, further studies should be made to evaluate temperatures
below 210 ◦ C and LHSV over 1,46 m 3 /(m 3 cat · hour) since there may be even better settings.