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HUNGARIAN JOURNAL
OF INDUSTRY AND CHEMISTRY
VESZPREM
Vol. 41(2) pp. 109-114 (2013)

MOL Department of Hydrocarbon- and Coal Processing, University of Pannonia, Egyetem u. 10.,

Liquid engine fuels are the main source of power for transportation in the passenger sector. It is the projection of the
European Union (EU) to reach 10% utilisation of renewable fuels by 2020. To achieve this goal the EU created the
2003/30/EC and furthermore the 2009/28/EC Directives. For example, the feedstocks of these renewable engine fuels can
be non-edible oil plant hybrids, such as rapeseed oils with high euric acid content obtained from special hybrids of rape
(e.g. Brassica napus) waste lards (used cooking oil and slaughterhouse lards). If the preconditions of utilisation are given
with respect to the sustainability and technical compatibility of motor engines and vehicle construction, these bio
components can be blended with motor fuels in large quantities. Considering the properties of currently used first
generation biofuels, the maximum amount of bio-component in engine fuels is approximately 7 (v/v)% fatty acid-
methylester in diesel fuels. A reliable production technology of second generation biofuels, which can be blended into
diesel fuels is the heterogenic catalytic hydrogenation of triglycerides and waste lards. Furthermore, isomerisation can
improve the quality of a bio-paraffin mixture. In this context, we studied the isomerisation of bio-paraffin mixtures,
which were obtained from the hydrodeoxygenation of vegetable oil. The characteristics of these products were
favourable, such as their cetane number being higher than 75, for example. The actual EN590:2013 standard does not
limit the blending ratio of the paraffinic bio-component in diesel fuels. Consequently, these products obtained by the
catalytic hydrogenation of vegetable oils can be blended into gasoil by up to 10 % or even more to meet the above EU
requirements with respect to the utilisation of renewable fuels.

Keywords: bio gasoil, hydrodeoxygenation, catalytic conversion, biofuels, blending diesel fuels

Interest in alternative fuels is on the rise due to the
unequal presence of the fossil energy carriers, the
periodic rise in the price of fossil fuels, the need for
decreasing dependence on crude oil, and the regulations
of the European Union. They can play a significant role
in achieving the EU plan to reach a 10% energy ratio of
total fuel consumption using alternative fuels by 2020.
Thus, the application of the biofuels can be increased to
a large degree in the long- and medium-terms. For
example, in some countries the domestic demand on
biofuels could increase to 20% by 2030, along with the
decrease in the demand for engine fuels that could be up
to 70%. The world's energy production from biomass
could reach 5% by 2050 [4, 5]. Accordingly, to ensure
the availability of this feedstock the production costs
could decrease. To achieve these goals, the EU created
several directives (1998/70/EC, 2001/77/EC,
2003/17/EC, 2003/30/EC, 2003/87/EC, 2009/28/CE,
and 2009/30/CE). Natural triglycerides like vegetable
oils (edible or non-edible/waste) can be feedstock for
biofuels as alternative energy sources [6, 7], such as
special breeding non-edible oil plants [8, 9], animal fats
or waste cooking oil [10, 11]. During the conversion of
natural triglyceride molecules to bio-gasoil the
following reactions take place [1, 2, 3]:

and reduction)
" decarboxylation,
" decarbonylation
o removing of other heteroatoms (sulphur,
nitrogen, phosphorous, and metals),

triglyceride molecules,
o water-gas shift reaction
o methanisation,
o cyclisation, aromatisation, etc.
During the HDO reduction reaction normal paraffins
are formed with carbon numbers that are equal to the
fatty acids in triglycerides. In the case of
decarboxylation and decarbonylation reactions (HDC)
normal alkanes are produced, where the carbon number
is one less than that of fatty acids of the original
vegetable (Fig.1).

Bio-gasoil is a mixture of gasoil with the boiling
range of iso- and normal-paraffins. It can be obtained by
the hydrogenation of vegetable oils and natural triglycerides

Figure 2: The freezing point of iso-paraffins as a function of
the branch position

from other sources. These constitute the second
generation biofuel components of diesel engines. They
have good quality characteristics, such as high cetane
number, good flow properties, unlimited mixability with
engine fuels, and the a production line compatible with
existing refinery structures [18, 19]. The actual EN
590:2013 standard does not limit the blending ratio of
second generation bio-components, while the blending
of biodiesel is limited to 7 v/v%. All the above
mentioned aspects of alternative fuels can rationalise the
investigation of the hydrogenation of non-traditional
feedstock sources. These are the vegetable oils that can
be obtained from non-edible hybrid oil-plants, rapeseed
oil from Brassica napus with high euric acid content to
produce diesel fuel blending components with good
flow properties in colder conditions (below +5 °C). The
freezing point of iso-paraffins from bio-sources is lower
than for equal chain length normal-paraffins (Fig.1)
[12-15, 17]. Thus, products with high iso-paraffin
contents have more favourable cold flow properties
(CFPP) with cloud points at lower temperatures (Fig.2).
The aim of our work was the production of diesel gasoil
blending components via the isomerisation of paraffin
mixtures obtained from the hydrodeoxygenation of
rapeseed oil with high euric acid content.

In this work, a diesel gasoil bio-blending component
production technique was investigated that meets the
requirements of the EN:590 Standard with the
possibility of blending it with engine fuels in unlimited
quantities. Thus, the hydrodeoxygenation of natural
triglycerides and further the isomerisation of the
obtained bio-paraffin mixture were investigated over the
Pt-SAPO-11 catalyst [16] developed in-house. The
effect of the operation parameters, such as temperature,
pressure, and liquid hourly space velocity (LHSV) was
studied on the yield, composition, and utilisation
properties of the products.

The experimental tests were carried out in one of the
measured sections of a high-pressure reactor system
containing two tubular reactors with a isothermal
catalyst volume of 100 cm³. The reactor system
contained all the equipment and devices applied in the
reactor system of a hydrotreating plant. The apparatus is
suitable for maintaining if not succeeding the industrial
precision of main process parameters.

The main properties of the feedstock materials and
products were determined by standard methods. The
hydrocarbon composition of the bio-paraffin mixture was
determined by high temperature gas chromatography
(Shimadzu 2010 GC [column: Phonomenex Zebron
MXT]).

The ranges of the applied process parameters in the
isomerisation test on the basis of our earlier
experimental results [13, 14, 17, 20-23] were as follows:
temperature 300-360 °C, total pressure 20-80 bar,
liquid hourly space velocity (LHSV) 1.0 h^-1, and
H₂/feed volume ratio of 400 Nm³ m^-3.

The feedstock of the catalytic tests was a bio-paraffin
mixture, which was obtained from the hydrodeoxygenation
of rapeseed with euric acid produced in Hungary. It was
properly filtered as a pre-treatment. The main properties
of the feedstock material are shown in Table 1. The
catalyst was Pt-SAPO-11 (0.5 % Pt), the main
properties of this can be found in Table 2.

The first step was to produce a bio-paraffin mixture
with a boiling range of gasoil from rapeseed with a high
euric acid content. The properties of the bio-paraffin are
summarised in Table 1. The commercially available
NiMo/Al₂O₃ catalyst was utilised for the production of
the bio-paraffin mixture. During the catalytic test the
employed operation parameters were as follows: 320-
380 °C, 20-80 bar, LHSV = 1.0 h^-1, and H₂/CH ratio of
600 Nm³ m^-3 [8]. It was found that the favourable
operation parameters are 340 °C, 40 bar, LHSV=1.0 h^-1,
and H₂/CH ratio of 600 Nm³ m^-3. The tested catalyst is
suitable for the production of bio-paraffin mixtures with

high yields from natural triglycerides. Due to the
moderate acidity of this catalyst, the formation of iso-
paraffins was lower (5 wt%, Fig.3). Accordingly, the
CFPP of the products was found to be high (27 °C). The
product fraction produced in this way, in practice,
cannot be blended into diesel fuels in low temperate
zone countries. It is necessary then for the improvement
of CFPP via the catalytic isomerisation of this mixture
with high normal-paraffin content [10, 11]. A large
amount of bio-paraffin mixture was produced in a
thousand hour, long-term catalytic test. The target
fraction of the isomerisation tests was the 180-360 °C
boiling range, which is the boiling range of gasoil. The
yield of the target products was higher than 94 % in all
operation parameter combinations (Fig.4). The lighter
fraction with a boiling range of up to 180 °C contains
mainly iso-paraffins, which can be outstanding gasoline
blending components due to their high octane numbers
(>85).

We found that by adjusting the operation parameters,
such as increasing the temperature, and decreasing the
LHSV, the yield of the target fraction was decreased
due to the higher yield of the cracking reaction. The
target fraction obtained between 70% and 80%

r. 25

S 20

•= c"

I Sl5

ca ~k

600 700

time on stream, hours

200 300 400 500

Figure 3: Hydrogenation of rapeseed oil with high euric acid content
(diamond: residual triglyceride, square: iso-paraffin content, cross C₂₁/C₂₂ ratio)

Figure 5: The iso-paraffin concentration of the target fraction
as a function of operation parameters (pressure: 40 bar, liquid
hourly space velocity: square 1.0 h^-1, diamond 2.0 h^-1, triangle
3.0 h^-1)

Figure 4: The yield of the target fraction as a function of
operation parameters (pressure: 40 bar, liquid hourly space
velocity square: 1.0 h^-1, diamond 2.0 h^-1, triangle 3.0 h^-1)

310 330 350 370

• muliti-branchiNi paraffins ® mono-branched paraffins
100

Figure 6: The composition of the products as a function of
operation parameters (pressure: 40 bar, liquid hourly space
velocity: 1.0 h^-1)

¹300°C "320'C "340'C "360°C

Pressure, bar

Figure 7: CFFP of the products as a function of operation
parameters (liquid hourly space velocity: 1.0 h^-1, H₂/feed ratio:
400 Nm³ m^-3)

contained C₁₇-C₂₂ hydrocarbons, as well as other (C₁₃-
C₁₆) hydrocarbons from the boiling range of gasoil. The
iso-paraffin content of the target fraction increased
significantly with the operating temperature (Fig.5). The
increase of the iso-paraffin concentration occurred at
360 °C then at higher temperatures it started to decrease,
due to the thermodynamic hindrance of the exothermic
reactions, and the higher rate of cracking reactions.

Up to ca. 320 °C, mainly mono-branched iso-
paraffins were formed and were by in large mono-ethyl-
paraffins (Fig.6). The freezing points of these products
are much lower than normal-paraffins and the cetane
number is high enough for a fuel additive. The greater
formation of mono-methyl-paraffins over the SAPO-11
catalyst can be explained by the reduced formation of
iso-paraffins due to steric hindrance. At 340 °C or
higher, the formation of multi-branched isomers was
significant (Fig.6). These compounds have better cold
flow properties (below -20 °C), but their cetane
numbers are high enough (30-45) as shown in Fig.2.
The favourable operation parameters in terms of bio-
gasoil yield and iso-paraffin concentration were as
follows: T = 360 °C; p = 40 bar; and H₂/feedstock ratio
= 400 Nm³ m^-3. The CFPP values of the products as a
function of temperature and operation pressures are
shown in Fig.7. These components have low enough
CFPP values to blend into diesel gasoil in moderate
amounts. On the basis of the experimental results, it was
concluded that the production of bio-gasoil meets the
standard's requirements with a CFPP value of max.
+5 °C and 70% iso-paraffin content (Fig.8) in the case
when the raw material contains 8% C17—C22 iso-
paraffins.

Based on our experimental results, it was concluded that
the NiMo/Al₂O₃ catalyst is suitable for the long-term
production of bio-paraffin mixtures from natural
triglycerides via catalytic hydrodeoxygenation.
Furthermore, the investigated Pt-SAPO-11 catalyst is
suitable for improving the quality of a bio-paraffin
mixture that was obtained from the hydrodeoxygenation
of rapeseed oil with high euric acid content. During the
isomerisation with optimised operation parameters, the
yield of the target fraction was higher than 94%. At
340 °C or higher the iso-paraffin content is close to
70%. Consequently, the cold flow property of the cloud
point is lower than +5 °C. Therefore, this approach can
produce gasoil bio-blending components with good
utilisation properties, such as high cetane number, and
low temperature values for cold flow properties.
Overall, the products described here are suitable for
blending components of diesel fuels with concentrations
of 10% or higher.

Figure 8: Cold flow properties as a function of iso-paraffin concentration
(solid squares: cold filtering clugging point, hollow diamonds: cloud point)

We acknowledge the financial support of the Hungarian
State and European Union under TAMOP-4.2.2.A-11/1/
KONV-2012-0071 and TAMOP-4.1.1.C-12/1/KONV-
2012-0017.

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Fatty acid		Paraffin
C16:0	2.3	^C14-	0.2
C16:1	0.1	^C14	0.1
C18:0	1.2	C15	0
C18:1	28.8	C16	2.3
C18:2	12.4	^C17	29.5
C18:3	8.3	^C18	28.8
C20:0	0	^C19	6.1
C20:1	4.8	^C20	5.6
C22:0	0.1	^C21	14.8
C22:1	41.8	^C22	12.5
other	0.2	^C22+	0.1