DD258025A1 - USE OF MODIFIED SILICONE GELS FOR REGENERATING ALTOELS - Google Patents

Abstract

The invention relates to the use of modified silica gels for the adsorptive regeneration of allografts, especially of mineral lubricating oils. The aim of the invention is the regeneration of Altoelen under improved economic conditions. The object of the invention is the use of suitably modified adsorbents for the regeneration of Atloelen. This object is achieved by the fact that wide-pore silica gels less than or equal to 0.045 mm in size, whose texture, structure and surface-chemical properties are modified by treatment with digested mineral acids, in an amount of 0.05 to 2 parts per part by weight of oil at temperatures of 343 to 393 K and reaction times of 0.2 to 1 h are used.

Description

Field of application of the invention

The invention relates to the use of certain modified silica gels for the adsorptive regeneration of waste oils, especially of mineral lubricating oils. Adsorptive regeneration can be used in petroleum industry operations as a preparatory or treatment process stage, or as a direct regeneration process.

Characteristic of the known technical solutions

The reuse of used, polluted oils is the subject of numerous investigations, since the repeated use of these high-quality products is economically, supply-politically and ecologically necessary. Bleaching earth, diatomaceous earth, Fuller's earth, perlite, activated bauxite, charcoal and macroporous polymers are already used as adsorbents for prepurification or as a process stage in multi-stage regeneration processes in the hitherto customary processes.

Thus, according to DD 214143, after removal of the readily volatile constituents, a refining of the used oil with 3 to 10% by mass of bleaching earth is proposed.

According to CH 183208, the regeneration of the waste oil is carried out by reacting the oxidation or aging products with alkaline earth oxides or hydroxides.

In the recycling technologies LUBREX ^R (Buss AG, LUWA) Waste oil is worked up by carrying out after a thermal treatment for separation of volatile components in a reactor a reaction with an alkaline compound such as alkali carbonate or alkali metal hydroxide, at 230 to 260 C ^c.

According to DE 2624196, the waste oil to be worked up is prepurified by means of macroporous polymers (pore diameter 6 to 300 Å).

According to DE 2824196, the waste oil is first mixed with isopropanol and insoluble constituents are separated by filtration. Subsequently, the oil is treated with 5 to 25% by weight of bleach, such as bleaching earth or activated carbon.

FR 2453311 describes the purification of used lubricating oils with silica gels whose average pore diameter is of the order of 20 to 3000 Å and whose pore volume is 0.2 to 2 cm ³ / g.

The above methods are used especially when large amounts of waste oil are processed. They are associated with a large process engineering effort. The adsorbents used (bleaching earth, diatomaceous earth, Fuller's earth or macroporous polymers) have not enough specific adsorption and are sometimes very expensive. So bleaching earth is not regenerable and must be discarded. The same applies to the very costly diatomaceous earth. When using macroporous polymers, the regeneration of the adsorbents with suitable solvents is very complicated and causes additional costs.

It can be deduced that the known technical processes have not yet reached a specific use of adsorbents.

Object of the invention

The aim of the invention is the regeneration of waste oils under improved economic conditions.

Explanation of the essence of the invention

The object of the invention is to regenerate waste oils by using suitably modified adsorbents. This object is achieved in that far-pore silica gels of grain size equal to or less than 0.045 mm, whose texture, structure and surface-chemical properties are modified by treatment with dilute mineral acids, in an amount of 0.05 to 2 parts per part by weight of oil at temperatures of 343 to 393K and reaction times from 0.2 to 1H.

The adsorbents used according to the invention are the undersize fractions of synthetically produced silica gels which are modified by subsequent treatment with dilute mineral acids. A subsequent grinding to eliminate coarse-grained parts, as they naturally arise by abrasion or bursting of gel particles, is for the use of the invention is advantageous. The acid treatment of silica gels leads to changes in their texture, structure and surface chemistry. Thus, a significant decrease in specific surface area, an increase in pore volume and a shift in pore distributions occur. The structural changes consist in the transition of the silica gel network into a higher-order state. In addition, modification of silica gels by acid treatment results in substantial removal of sodium and other metal ions affecting adsorption properties and increases silanol group density.

It has surprisingly been found that such modified silica gels have a specific adsorption for the aging products in mineral oil products.

The acid treatment can be carried out in a known manner with 3 N HCl for 3 to 24 h at 90 to 100 ⁰ C and a solid-liquid ratio of 1:10, although other mineral acids can be used. Due to the characteristic changes, a removal of polymerization products, ineffective additives and oxidation products is achieved in a gentle manner by the use of said finely divided silica gels. The reformation of resinous ingredients is avoided.

The finely divided silica gels used according to the invention are activated by conventional thermal treatment before use. The regeneration is advantageously carried out in heated stirred reactors, which allow intensive mixing of the adsorbent with the waste oil to be worked up.

The refining time is varied between 0.2 and one hour, depending on the desired degree of refining and the state of aging of the oil to be worked up.

After completion of the adsorptive regeneration, the purified oil is separated by conventional filtration devices. The spent refining agent obtained as a filter cake can be returned to the process after thermal regeneration at 573 to 873 K and used again to remove unwanted constituents of the waste oil. After several regeneration cycles, re-treatment of the adsorbent with mineral acids is expedient.

Example 1:

Type B silica gel (VEB Chemische Werk Bad Köstritz) was modified by extraction with 3 η HCl at 363 K for 10 hours and a solid-liquid ratio of 1:10.

After the chloride-free washing was activated at 473 K. In a stirred reactor 151 of a dirty motor oil were mixed with 3 kg of the modified silica gel and heated with stirring.

After reaching the regeneration temperature of 373 K was left for 30 min at this temperature. Subsequently, the separation of the silica gel was carried out by filtration.

The characteristic values of the treated oil are contained in Table 1. The contaminated silica gel obtained as a filter cake can be regenerated by thermal treatment at 853 to 873 K and used again for waste oil treatment.

Example 2

Mineral used oil, which is obtained as spent lubricant, was worked up according to the procedure described in Example 1.

The following parameters were observed:

Ratio of used oil: silica gel: 1: 0.15

Treatment temperature: 373K

Duration of treatment: 40min.

The thermal regeneration of the silica gel separated from the oil by centrifugation was carried out at 873 K.

(Characteristic values of the oil are contained in Tab. 1)

Example 3: ·

2 kg of the thermally regenerated silica gel were used according to Example 1 for the regeneration of 101 motor oil. The 30-minute treatment was carried out in a stirred reactor at 363 K.

The suspension was separated by filtration. (The characteristic values of the oil are contained in Tab. 1). The used oil prepared in accordance with Examples 1 to 3 can be subjected to further distillation preparatory steps in accordance with the intended reuse.

Table 1: example

waste oil

density .8979 .8965 .8950 .8928 20 ^° C (g / cm ³ ) viscosity 48.6 42.6 45.0 45.6 50 ° C [mm ² / s] Neutralization number 0.65 0.11 0.20 0.16 [mg KOH / g] saponification 3.27 2.09 2.6 1.98 [mg KOH / g] ash content 0.5 0.1 0.1 0.1 [Wt .-%]

Claims (2)

-1 - zoö uza claim: Use of modified silica gels for the regeneration of waste oils, characterized in that wide-pore silica gels of grain size equal to or less than 0.045 mm, whose texture, structural and surface chemical properties have been modified by treatment with dilute mineral acids, in an amount of 0.05 to 2 parts per part by weight of oil at temperatures of 343 to 393 K and reaction times of 0.2 to 1 hour are used.