Hydrogenated vegetable oil

Hydrogenated vegetable oil
other names	HVO
Trade names	Neste MY Renewable Diesel, CARE Diesel
Brief description	Vegetable oil based fuel component or fuel
origin	biogenic, synthetic
Characteristic components	Alkanes, linear and branched
properties
Physical state	liquid
density	775-785 kg / m 3
calorific value	44 MJ / kg
Cetane number	70-90
Flash point	> 60 ° C
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 304 EUH: 066 P: 301
UN number	1202
Hazard number	30th
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

As hydrogenated vegetable oils (HVO, English Hydrogenated or Hydrotreated Vegetable Oils ) vegetable oils are referred to by a catalytic reaction with hydrogen ( hydrogenation ), in hydrocarbons are converted. Through this process, the properties of the vegetable oils are adapted to fossil fuels (especially diesel fuel ) so that they can be added as an admixture or completely replaced.

Manufacturing

Hydrogenated vegetable oils can be produced in existing refineries together with other fats and mineral oil components as well as in our own vegetable oil plants.

Hydrogenation in mineral oil refineries

During the hydrogenation in mineral oil refineries, the vacuum gas oil resulting from the processing of the mineral crude oil is mixed with vegetable oils such as Rapeseed oil added in proportions of up to 30 percent.

In the subsequent hydrotreating , these vegetable oils are then chemically modified together with the mineral oil fraction by removing the so-called heteroatoms such as sulfur , oxygen and nitrogen with the incorporation of hydrogen . In addition to the hydrocarbons produced from the vegetable oils, hydrogen sulfide (H ₂ S), water (H ₂ O) and ammonia (NH ₃ ) are produced as by-products . In a subsequent step ( hydrocracking ), the hydrocarbons are again split into smaller chains ( cracking ) with the incorporation of hydrogen , with methane (CH ₄ ), propane (C ₃ H ₈ ) and water being formed as by-products.

In a more modern process, hydrocracking is dispensed with and the triglycerides are split after the addition of the vegetable oil in a process known as middle distillate desulphurisation. In this way it is possible to produce fuels with a rapeseed oil content of 10 to 30 percent, whereby the vegetable oil is present in the form of paraffins (mixtures of saturated hydrocarbon chains). The biodegradability of the vegetable oils is lost in the process, and the need for hydrogen for the hydrogenation process increases compared to a pure mineral oil refining process.

Vegetable oil plants

In addition to processing in the mineral oil refinery, hydrogenated vegetable oil can also be used in plants specially designed for vegetable oils and fatty residues and waste materials. The most advanced technology is the process of producing the fuel known as NExBTL by the Finnish company Neste Oil . While palm oil was mainly used for production in the beginning , the palm oil content could be reduced to approx. 20%. From a technical point of view, palm oil could be dispensed with entirely; more than 10 different raw materials can be used for production.

For the process, the vegetable oils and other fats are pretreated by separating solids and water from the oils. This process is analogous to the refining of vegetable oil or biodiesel production. This is followed by a hydrotreating process in special fixed bed reactors with cobalt or nickel molybdenum catalysts at temperatures of 350 to 450 ° C and a hydrogen partial pressure of 48 to 152 bar, at which the fuel is produced.

About 1.23 tons of vegetable oil are used for one ton of fuel for the conversion, the by-product mainly being fuel gas .

properties

The paraffins produced from the vegetable oils during mineral oil distillation consist of mixtures of saturated hydrocarbon chains of different lengths. The density of these hydrogenated vegetable oils is around 780 kg / m ³ and is therefore significantly lower than that of mineral diesel fuel; the cetane number is around 70 and up to 99, significantly higher than that of diesel fuel, biodiesel and pure vegetable oil fuel . The fuel produced in this process, which is based partly on mineral oil and partly on vegetable oils, meets the requirements of the standardization for diesel fuel if the process is carried out accordingly and can be used accordingly.

Due to the lack of mineral oil components, NExBTL fuel has a lower total density of 775 to 785 kg / m ³ than is prescribed for diesel fuel. It is free from oxygen, nitrogen, sulfur and aromatics .

Effect of the admixture

The production of hydrogenated vegetable oils (and animal fats) is currently to take place primarily for admixture with existing fuels for automobile drives, with an admixture to diesel fuels in particular being the focus. Due to the lack of experience with hydrogenated vegetable oils, there have so far been hardly any studies on the changed fuel properties, according to Kaltschmitt et al. However, for diesel fuels there is evidence of a reduction in exhaust emissions due to the admixture.

Care Diesel

A fuel based mainly on HVO is also marketed as CARE Diesel®, but currently has no fuel approval in Germany.

literature

• Hydrogenation. In: Martin Kaltschmitt, Hans Hartmann, Hermann Hofbauer (Hrsg.): Energy from biomass. Basics, techniques and procedures. Springer Verlag, Berlin and Heidelberg 2009; Pp. 746-748. ISBN 978-3-540-85094-6

Individual evidence

1. ↑ ^{a b} safety data sheet . October 1, 2019, accessed December 12, 2019 . 
2. ^ Sustainably produced palm oil. March 29, 2016, accessed December 12, 2019 . 
3. ^ Renewable raw materials. March 18, 2016, accessed December 12, 2019 . 
4. ↑ CARE Diesel®
5. ↑ Media report: Authorities do not allow clean diesel