Hiukan huono mutta olkoon nyt kun ehdin jo kiiruissani tämän viskaamaan:
http://www.people.umass.edu/ktheis/tfa.htm
"Traditionally, animal fats like butter and lard (saturated fats) were used as spreads and for baking. Vegetable oils (unsaturated fats) were cheaper, but as liquids they were not a suitable alternative. Unsaturated fats have a structure with kinks; these kinks result in a liquid state at room temperature. In the early 20th century, a chemical process called hydrogenation was developed that
converts vegetable oils into saturated, more solid fats (margarine and vegetable shortening). When it was discovered that eating saturated fats increases the risk for coronary heart disease, the food industry turned to partial hydrogenation. This process lowerd the content of saturated fat in vegetable shortening and margarine, but also dramatically increased the amount of a certain kind of fat - trans fat - in our diets. While suppliers praised processed vegetable oils as healthy unsaturated and cholesterol-free substitutes for animal fats, there is now strong evidence that introducing trans-fatty acids into our diets does more harm than good."
ED: lisäys
http://www.gkss.de/euprojekte/PSP6/CAME ... ctives.pdf
Mielenkiintoisia nuo eräät prosenttiluvut, mitähän meille oikeen joskus on syötetty, lihavointi loppupulella:
Josta:
"EU Project CAMERTOIL, Objectives 1
EU Project CAMERTOIL
“A new process using membrane reactor technology to improve the healthcare
aspects of hydrogenated edible oils”
Contract no QLK1-CT-2002-02234
1. OBJECTIVES AND EXPECTED ACHIEVEMENTS
1.1. SCIENTIFIC AND TECHNICAL OBJECTIVES
The global objective of this project is the development of a new continuous hydrogenation process for
edible oils based on a catalytic membrane reactor technology that permits reduction of the trans fatty
acid content in the final hydrogenated products to below 1%. Nowadays, a trans fatty acid content
between 3-5% will be considered a good result. Additionally, this new process will be innovative
because it simplifies the conventional process of oil hydrogenation by eliminating the filtration step, it
improves the efficiency of the current process, it reduces the wastes generated and energy and raw
material consumption.
The main objectives can be divided into the following scientific and technical objectives:
Scientific objectives:
e Selection and characterisation of suitable catalysts. As well as the catalysts traditionally employed
in hydrogenation processes, other catalysts will be studied in order to evaluate their ability to
minimise formation of the trans fatty acid.
e Determination of the catalytic activity and selectivity to avoid cis-trans isomerization of the selected
catalysts in traditional hydrogenation process. The objectives are to determine the behaviour of the
granulated form of these catalysts, i.e. catalysts supported on alumina and zirconia, in the
hydrogenation reaction. Factors to be investigated include selectivity to trans fatty acid formation at
different pressures and temperatures, the deactivation of the catalysts due to coke deposition and
methods of regeneration.
e Determination of the fluidodynamic characteristics of different porous supports, i.e., polymeric or
ceramic supports, and establishment of technologies to support the selected catalysts.
e Development of various catalytic membranes based on the selected supports and catalysts.
Establishment of the necessary pore size to achieve hydrogen diffusion, study of the characteristics
of this catalytic material and regeneration possibilities.
e Study of the developed catalytic membranes for hydrogenation of edible oils at different flux,
temperatures and pressures. Investigation of hydrogenation selectivity and trans fatty acid
production, deactivation and conditions required for regeneration. Evaluation of the behaviour of the
support and supported catalyst under different operating conditions.
e Design of a catalytic membrane based on the hydrogenation process and determination of the
operating conditions that result in a low trans fatty acid content (less that 1%) in the final
hydrogenated products.
Technical objectives:
e Improvement, simplification and reduction of environmental impact of the traditional process of oil
hydrogenation by reduced selectivity to the trans fatty acid isomer, reduction of consumption of
resources by at least 40%, reduction of catalyst losses by 50%, reduction of waste by 60-70% and
elimination of the filtration step used to separate the catalyst from the product. This latter process
modification will lead to an important saving of energy and reduction of waste generated in the
filtration step. Presently, this filtration process is carried out in a press filter with heating.
The estimated reduction of resources consumption (energy, water, hydrogen and catalyst) is based
on the improvement of gas-oil contact, the decreasing the hydrogenation temperature and
hydrogen pressure and the elimination of filtration step that will be obtained with this new process.
EU Project CAMERTOIL, Objectives 2
The reduction of the operational temperature and hydrogen pressure in the hydrogenation process
will permit to decrease the needs of energy, water to refrigeration and hydrogen requirements. The
elimination of filtration step that is carried out at high temperature will permit to reduce the
consumption of energy and will avoid the use of water to clean the filter. In the new process it is
possible to achieve higher surface area of the catalyst in the reactor reducing the catalyst amount
necessary to the process. On the other hand, the catalyst is fixed to a membrane avoiding the
losses of catalyst in the filter and with the final products.
The estimated reduction in waste pro duction is based on the reduction of the percentage of catalyst
exhausted produced by ton of product, and the elimination of filtration step. With the elimination of
this step will be eliminated the effluents produced in the filter cleaning, the wastes of filter cloths
with remains of oil, catalyst and products (diatomeas) used to form the pre-cover necessary to
achieve an adequate degree of filtration for the catalyst with very small size.
e Development of a catalytic selective membrane that avoids trans fatty acid formation and a catalytic
membrane reactor that allows improved safety of hydrogenated oils
by reducing the trans fatty acid
content from about 30% (average content in margarine) to 1%. This membrane will have structural
characteristics, flux behaviour, regeneration and cleaning capabilities, which permit a viable
industrial application for the designed catalytic reactor.
e Improvement of the quality of the hydrogenated oils by reducing the trans fatty acid content to below
1%. These acids have a harmful effect on human health because they have been shown to increase
the level of harmful cholesterol in blood."