CS275868B6 - Hydrogenation process of vegetable oils, fats and free fatty acids - Google Patents

Abstract

Hydrogenation process in the presence of hydrogen a nickel catalyst or other heterogeneous species platinum-based catalysts a palladium is that the reaction proceeds in the tangential flow of the mixture and the mixing region is characterized by the Reynolds range mixing criteria 1 to 6.104.

Description

The present invention relates to a process for the hydrogenation of vegetable oil, fat or unsaturated free fatty acids in the presence of a Ni catalyst or other suitable type of catalyst and dispersed hydrogen, in which a very efficient tangential flow of said reaction mixture is produced by suitable stirring.

Hydrogenation of oils, fats and free fatty acids has been and still is one of the important technological processes of the fat industry. This operation obtains suitable fats for food purposes for the production of margarines, edible fats, emulsifiers and other types of products, but this technological process also obtains basic raw materials for the production of technical products such as saturated fatty acid derivatives, soaps, etc.

One of the most important factors in the hydrogenation process in a heterogeneous arrangement is the mass transfer, in particular hydrogen, by the bulk phase to the surface of the catalyst grains, the transport of unsaturated fatty acids to this surface and, of course, the return processes. Therefore, in a batch hydrogenation process, a suitable mixing method will significantly affect the mass transfer and thus the reaction rate and possibly the selectivity. To optimize the hydrogenation, it is therefore important to pay attention not only to the influence of the stirring intensity, but also to the influence of the geometric conditions of the reactor itself, the influence of the stirrer geometry on the hydrogen distribution in the reaction mixture and its operating characteristics. Makrokinetické These elements form, in addition to the reaction conditions such as pressure and hydrogen flow rate, temperature, and ^type: catalyst concentration, a significant set of the other technological parameters in the process of hydrogenation. In the current hydrogenation technology, two types of stirrers are used, which create either a radial or axial flow of the stirred liquid and thus a corresponding distribution of hydrogen and mass transfer efficiency. Therefore, a mixing device must meet several basic requirements in a complex three-phase system of a heterogeneous hydrogenation process. First of all, it should intensively disperse hydrogen in the form of a fine dispersion (bubbles), because the speed of the process is directly proportional to the interfacial surface. Furthermore, it is necessary to ensure intensive circulation, and thus essentially gas retention (average phase contact time). These requirements for agitators are compounded by the need to lift catalyst particles.

In the hydrogenation of fatty raw materials, turbine or propeller stirrers are used, usually with a ratio of the stirrer diameter to the reactor diameter of 0.3 to 0.4. Stirrers are no exception, where this ratio increases to 0.5. The modern solution at present is to place several stirrers on top of each other, mostly propeller. Nevertheless, even these types of stirrers do not fully meet the requirements for highly efficient mass transfer, and thus have relatively little effect on the rate of saturation of free or double fatty acid double bonds in triacylglycerols.

The process for the hydrogenation of vegetable oils, fats and free fatty acids in the presence of hydrogen and a nickel-based catalyst or other suitable heterogeneous catalysts eliminates these disadvantages, which consists in the reaction taking place in a tangential flow of the reaction mixture in a closed reactor and the mixing range characterized by the Reynoldso4 range. and mixing criteria 1 to 6.10.

The rate of saturation of the fatty acid double bonds is substantially increased by more intense mass transfer in the heterogeneous hydrogenation process by introducing the mixing method according to the invention. The tangential flow of the reaction mixture of hydrogenated material, catalyst and hydrogen produces a slow-running stirrer with an optimal ratio of stirrer diameter to side arm length. This results in a very fine dispersion of the hydrogen, a much longer residence time in the hydrogenated feedstock and a much more efficient mass transfer. The resulting effect represents a multiple increase in the reaction rate without reducing the selectivity of the process.

The process for the hydrogenation of oils, fats and fatty acids according to the invention is further illustrated by the following examples.

CS 275868 B 6 _q

Example 1

Semi-refined sunflower oil with an iodine value (hereinafter JC) of 136.2, an acid number (hereinafter CK) of 0.2 and a phospholipid content (hereinafter PL) of 0.01% by weight, in an amount of 3.5 dm ³ in the presence of Ni-catalyst, was hardened. (Nysel 0M-3) 0.2 wt. Ni / oil, hydrogen flow 360 dm ⁵ .h ^-1 (hydrogen supply was a pipe with a diameter of 8 mm in the center of the reactor 1 qm above the bottom), at a stirrer speed of 6.7 s ^-1 (anchor type) (Re = 1, 77.10 ⁴ ). The reaction rate constant was calculated to be 10.5.10 (min). JČ za. 100 minutes was 43.8. '

Example 2

The same semi-refined sunflower oil was hardened under the same conditions as in Example 1, except for the stirring speed, which was expressed at a speed of 16.7 s ¹ (Re = 4.42.10 ⁴ ). The reaction rate constant was 33.6.10 ⁵ (min ⁵ ). JČ reached the value of 35.3 in 50 minutes.

Example 3

The same semi-refined sunflower oil was hardened under the same conditions as in Example 1, except that a turbine mixer was used to create a radial flow of the reaction mixture. The speed was 6.7 s ^-1 (Re = 0.46.10 ⁴ ). The reaction rate expressed by the rate 3 -1 x constant was 3.1.10 (min). JC reached 86.1 in 120 minutes.

Example 4

The experimental conditions were the same as in Example 3, only the speed of the stirrer was higher, namely 20.0 3 ^-1 (Re = 1.4.10 ⁴ ). The rate of hydrogenation expressed by the rate constant was 10.5.1ο · ⁵ (min ^-1 ). JČ in 120 minutes had a value of 35.5.

Example 5

The experimental conditions were the same as in Example 1, except that a propeller stirrer according to ON 691019 was used, the stirrer speed was 20.0 s ¹ (Re = 1.4.10 ⁴ ). The rate of hydrogenation expressed by the rate constant was 7.5.10 ⁵ (min ^-1 ). JČ in 120 minutes had a value of 55.4.

Example 6

Semi-refined rapeseed oil with JČ 118.2, ČK 0.3, PL content 0.032% by weight was hardened under the same conditions as in Example 1. The reaction rate expressed by the rate constant was 9.9.10 ⁵ (min ^-1 ) (Re = 1, 77.10 ⁴ ). JC in 100 minutes had a value of 53.2.

Example 7

Distilled fatty acids obtained by cleavage of animal fat of JČ 60.2, ČK 195.6 under the same conditions as in Example 2 were solidified. JČ obtained in 60 minutes of hydrogenation had a value of 3.2.

Example 8

The semi-refined sunflower oil was hardened under the same conditions as in Example 1 (Re = 1.77.10 ⁴ ), except that the catalyst content in the reaction mixture was 0.05% by weight. Ni / oil. The reaction rate expressed by the rate constant was 8.2.10 ⁵ (min ^-1 ). The IC in 80 minutes of reaction was 71.2.

Claims (1)

PATENT CLAIMS Process for the hydrogenation of vegetable oils, fats or free fatty acids in the presence of hydrogen and a nickel catalyst at a concentration of 0.02 to 0.5% by weight, nickel / oil or other suitable types of heterogeneous catalysts based on platinum Pt, palladium Pd and others, characterized in that that the reaction takes place in a tangential flow of the mixture and the mixing area is characterized by the range of Reynoldsava criteria for mixing 1 to 6.10.