DD255741A1 - METHOD FOR PRODUCING INSULATING OILS - Google Patents

Abstract

The invention relates to a process for the preparation of preferably uninhibited Isolieroel with favorable low temperature properties and good aging stability from product flows of petroleum processing with only a small amount of auxiliary ingredients and without drastic lowering of the aromatic content. According to the invention, hydrocatalytically desulfurized middle distillates and / or high-cleavage hydrogenated gasoel and / or vacuum distillates are subjected as such or in a mixture to a microbiological partial dewaxing and refining with H 3 PO 4 and then the oil component is separated off in a manner known per se.

Description

Characteristic of the known technical solutions

To the quality of transformer oils are made in terms of electrical and low temperature properties exactly to be complied with demands. In addition, in order to ensure a long service life, sufficient stability against aging and oxidation processes must be ensured, with test methods according to Braaderund according to IEC publication No. 474 being used to assess the aging behavior.

For the production of transformer oils naphthenic basic oils are particularly suitable, but which are available in smaller and smaller amounts, so that increasingly mixed or paraffiribasische petroleum oils are used.

Especially with mixed or paraffin-based petroleum oils, the high content of n-paraffins negatively affects the low-temperature behavior.

There are a number of methods known, such as for the production of insulating oils interfering η-paraffins are at least partially removed or converted, or how components are produced, which on pour point depressants sufficiently well

In known manner, the oil component is separated by distillation from the hydrocarbon mixture.

Refining with bleaching earth is only required if an alkylnaphthalene type depressant is added to the oil.

The advantage of the process according to the invention is due to the order of the process steps of hydrocatalytic treatment, biological dewaxing and phosphoric acid refining.

In contrast to the prior art, it has been found that the hydrocatalytic treatment in the production of transformer oil does not necessarily have to be after the biological dewaxing and purification of the hydrocarbon fraction.

It has been found that in the production of transformer oil according to the method according to the invention a long trouble-free running time of the catalytic treatment stage is achieved without a prior fine cleaning of the hydrocarbon fraction. In addition, the hydrocatalytic treatment removes those substances which interfere with the aging stability of the oils, which otherwise pollute the auxiliary substance used for cleaning. The use of the hydrocatalytically treated hydrocarbon fractions in the biological dewaxing allowed there surprisingly better process management, with low residual normal paraffin contents than in straight-tun feedstocks are economically achievable. As a result, the cost of depressors can be reduced, which do not require bleaching earth treatment.

It is essential that obtained in the inventive order of the process steps, a particularly age-resistant oil

embodiments

The invention will be explained in more detail with reference to two exemplary embodiments:

example 1

A transformer oil is produced using the following process steps:

1. A paraffinic petroleum fraction boiling in the range 630-830 K at a temperature of 680K, a pressure of 30 MPa, a gas-to-product ratio of 500: 1 and a catalyst loading of 1 v / vh on a Ni-Mo catalyst. AI ₂ OaZSiO ₂ catalyst hydrocatalytically treated.

2. From the product of this sharp hydrocatalytic treatment, a transformer base oil fraction is separated by distillation, which meets a flashpoint requirement of at least 412 K (open cup) and contains 24% by mass of aromatics.

3. The 13Ma% n-paraffin transformant base oil fraction is micro-dewaxed by n-paraffin-teasing yeasts to 6.5Ma% n-paraffin sections.

4. In a finishing process, the base oil is extracted with 2.5Ma% phosphoric acid.

5. By adding 0.5Ma .-% of an ethylene-vinyl acetate copolymer, the pour point of the finished oil is lowered to 225 K. The transformer oil has a dielectric loss factor tan δ of 70 10 ^-3 and a mud content of 0.03 mass% after 28-day Baader aging.

Example 2

A transformer oil is produced using the following processes:

1. A vacuum distillate of the boiling range 620-810 K is in a large-scale plant on a Ni-Mo-Al ₂ OVSiOy fixed-bed catalyst at a contact load of 1 v / vh, a pressure of 23 MPa, a reaction temperature of 720 K and a gas product Ratio of 1 000: 1 subjected to a sharp hydro-catalytic treatment.

2. From the product thus obtained, a diesel oil fraction having an n-paraffin content of 11.5 mass% is separated.

3. The diesel oil fraction is micro-biologically de-paraffinized by n-paraffinutilizing yeasts to 6.0% by weight n-paraffin.

4. From the partially dewaxed diesel oil fraction, a base oil fraction is separated by distillation, which meets the flashpoint requirement of at least 412 K (open pot).

5. By treating this base oil component at 303 K with 2.5% by weight concentrated phosphoric acid, the level of basic nitrogen is lowered to 3 ppm.

6. By adding 0.5 wt% of an alkylnaphthalene type pour point depressant, a pour point pour point of 226K is adjusted.

7. In a final purification step, the oil is refined at 393K with 5Ma .-% bleaching earth.

The transformer oil has a dielectric loss facortan8 of 75 x 10 ^-3 and a mud content of 0.04% after 28-day Baader aging.

Claims (1)

Process for the preparation of insulating oils, preferably non-inhibited insulating oils with favorable low-temperature properties and aging stability from product streams of petroleum processing optionally with bleaching earth treatment and Depressatorzusatz, characterized in that under medium pressure hydrocentric desulfurized middle distillates and / or sharply split hydrogenated gas oil and / or vacuum distillates of the boiling 540 830K as such or in the mixture in the order of a microbiological partial dewaxing to an n-paraffin content of at least 9% by weight and refining with phosphoric acid, and thereafter, in a manner known per se, the oil component is separated by distillation from the hydrocarbon mixture, the bleaching earth treatment is carried out only with the addition of an alkylnaphthalene type depressant. Field of application of the invention The invention relates to a process for the preparation of preferably uninhibited insulating oil with favorable low-temperature properties and good aging stability from product streams of petroleum processing. speak to. According to DD-WP 109023, transformer base oils are produced by catalytic hydrorefining of suitable petroleum distillate fractions followed by molecular sieve dewaxing and fractional condensation. According to US Pat. No. 4,057,489, a transformer oil is produced and according to US Pat. No. 4,090,950 a low-level refrigerating machine oil is obtained by dewaxing the feed after hydrocatalytic refining on specific catalysts of the mordenite dithium and finally refining it by means of a bleaching earth or acid treatment. According to DD-WP 135390, a transformer oil is prepared by microbiologically partially dewaxing, hydrocatalytically treating petroleum distillates of the suitable boiling position and subjecting the distillatively separated base oil fraction to an acid and bleaching earth treatment. The main disadvantage of the method is that the biological Teilentparaffinierung can be performed only up to such residual levels of normal paraffins, which require a high addition of pour point depressors to oil. With a high addition of depressants, the aging resistance of the oil and the economy of the production are adversely affected. An improvement in the yield and quality of microbial biomass is achieved according to DD-WP 227445 by hydrocatalyst treating the petroleum distillates of their use in the cultivation stage, such that the aromatic content is drastically reduced and the n-alkane content is increased. For the production of transformer oils such a procedure of the hydro-catalytic treatment is therefore not suitable, because with the drastic reduction of the aromatic content, the gas absorption capacity of the oil deteriorates Object of the invention The aim of the invention is. To produce insulating oils, preferably uninhibited insulating oils from petroleum product streams, with only a minor amount of adjuvant. Explanation of the essence of the invention It is not the object of the invention to produce insulating oils, preferably non-inhibited insulating oils with favorable low-temperature properties, improved aging stability and long service life of the oils in transformers without drastically lowering the aromatics content. It has been found that the production of insulating oils, preferably uninhibited insulating oils, with favorable low temperature properties, improved aging stability and long life in transformers is possible when mid-distillates hydrocatalysts desulfurized under medium pressure conditions or subjected to gas oil and / or vacuum distillates of sharp fissioning hydrogenation and these products alone or in admixture following microbiological partial dewaxing, followed by careful refining with phosphoric acid.