Method for producing naphthenic process oils by hydrogenation

Abstract

The object of the invention is a method for producing naphthenic process oils that have a high content of naphthenic carbon atoms of 20-60 wt % and a low content of polycyclic aromatics of less than 3 wt %, determined in accordance with IP 346, by the hydrogenation of a process oil educt that has a high content of polycyclic aromatics. The method in accordance with the invention enables secondary extracts, such as are formed in the production of label-free process oils, even in a mixture with primary extracts, to be utilized in an economically meaningful way. The resulting process oils are likewise label-free, so that the use of PCA-containing process oils can be reduced and less of these substances will get into the environment. Through this the environment and in particular health are less stressed. In addition, the starting substances in this way can lead to a different use and no longer have to be added to heating oil. By avoiding heating oil, CO.sub.2 emissions are also reduced. Also, through the direct hydrogenation of DAE, high value naphthenic process oils are obtained by the method in accordance with the invention. The process oils that are obtained contain surprisingly high amounts of naphthenic hydrocarbon compounds. In addition, an object of the invention is the use of the process oils produced in accordance with the invention as a plasticizer or extender oil for natural and synthetic rubber mixtures or thermoplastic elastomers.

Claims

1. A method for producing naphthenic process oils that have a carbon distribution CA to CN to CP of 0-30 wt % to 30-65 wt % to 20-55 wt %, determined in according with ASTM D 2140, wherein the process oil starting material has a content of naphthenic carbon atoms CN less than or equal to 25% wt %, wherein a process oil educt is hydrogenated with hydrogen using a metal catalyst at a temperature between 200-400 C. and at a pressure between 80-250 bar, wherein the process oil educt is selected from the group consisting of distillate aromatic extract (DAE), secondary extracts obtained in production of TDAE or MES, educt mixture of DAE and secondary extracts, and mixtures thereof.

2. The method of claim 1, wherein the metal catalyst is based on a nickel, cobalt, molybdenum, chromium, vanadium, nickel-molybdenum, chromium-vanadium, a metal oxide, a metal sulfide, or a mixture thereof.

3. The method of claim 1, wherein the average residence time of the hydrogenation is 6-60 minutes.

4. The method of claim 1, wherein the aniline point of the naphthenic process oil is between 30 and 115, determined in accordance with DIN ISO 2977.

5. The method of claim 1, wherein hydrogenation is carried out at a temperature between 300-375.

6. The method as in claim 1, wherein the mixture is 75 wt % to 25 wt % up to 25 wt % to 75 wt % secondary extract to DAE.

Description

(1) The method in accordance with the invention is illustrated by means of the figures by way of example. Here:

(2) FIG. 1 shows a flowchart of the extraction process known from the prior art for production of TDAE and MES.

(3) FIG. 2 shows a flowchart of one embodiment of the method in accordance with the invention.

(4) FIG. 3 shows a flowchart of another embodiment of the method in accordance with the invention.

(5) FIG. 1 shows the second extraction step of the conventional extraction for production of TDAE or MES. The primary extract 2 is sent to an extraction column 1. The primary extract is a mixture of different hydrocarbon compounds, including aromatic hydrocarbon compounds and polycyclic aromatics. At the same time solvent is supplied to the extraction column via line 3. The raffinate 4, for example a TDAE or MES, is taken from the top of the column. At the same time a secondary extract 5, which has a high content of polycyclic aromatics, is taken from the bottom of the column.

(6) FIG. 2 shows the course of the method in accordance with the invention. A process oil 5 with a high polycyclic aromatic content, as obtained, for example from the method shown in FIG. 1, is sent to a hydrogenation reactor 6 and hydrogenated there with hydrogen. A naphthenic process oil 7 and stripping oil 8 are taken from the hydrogenation reactor 6. The naphthenic process oil 7 has a PCA content below 3 wt %. In a less preferred embodiment, the method can also be conducted so that end products with a relatively high residual content of aromatics, the PCA content of which can be >3 wt % in accordance with IP 346, are obtained. These relatively high-aromatic fractions can be added via line 9 to the primary extract 2 or, alternatively, can be sent to the extraction column 1 and are suitable as feedstock for the production of label-free process oils either by itself or in a mixture with primary extract.

(7) FIG. 3 shows the production of a naphthenic process oil 7 by direct hydrogenation of a primary extract 2 in a hydrogenation reactor 6. In addition to the naphthenic process oil 7, a stripping oil 8 is obtained. A crude oil 10 is subjected to atmospheric distillation 11. The resulting atmospheric residue 12 is solely processed further in a vacuum distillation 13. A distillate 14 and a vacuum residue 15 are obtained. The distillate 14 is separated into the primary extract 2 and a raffinate 17 in an extraction column 16.

EXAMPLES

Example 1

(8) A secondary extract with a polycyclic aromatic content of 45 wt % according to IP 346 and C.sub.N content of 22 wt % and C.sub.P content of 23 wt % was input with hydrogen to a hydrogenation reactor at a temperature of 340 C. and pressure of 200 bar. The reactor contained a nickel-molybdenum catalyst (Axens HR548, Evonik). Hydrogenation was carried out at an average residence time of 25 min. 94% naphthenic process oil and 6% stripping oil were obtained.

(9) The resulting naphthenic process oil has the properties given in Table 1.

(10) TABLE-US-00001 TABLE 1 Properties of resulting naphthenic process oil from Example 1 Properties of process oil in accordance with Example Benz[a]pyrene [ppm] <1 Sum PAH [ppm] measured by <10 RL 2005/69 EC Viscosity at 40 C. [mm.sup.2/s] 612 Viscosity at 100 C. [mm.sup.2/s] 39 C.sub.A according to ASTM 3 D 2140 [wt %] C.sub.N according to ASTM 57 D 2140 [wt %] C.sub.p according to ASTM 40 D 2140 [wt %] Aniline point [ C.] 93

Example 2

(11) In addition, the properties of different products that [were] obtained by the method in accordance with the invention were compared with those of a traditional process oil TDAE. Table 2 shows a comparison of the different production conditions and data for three products produced in accordance with the invention (hydrogenation products) in a comparison with a TDAE. The hydrogenation products were prepared analogously to the example described above. The mixture of primary extract to secondary extract was 50:50.

(12) TABLE-US-00002 TABLE 2 Production conditions and properties of process oils produced in accordance with the invention and a comparison process oil Hydrogenation Hydrogenation Hydrogenation products from products from products from primary extract primary/secondary secondary Method of determination (DAE) extract mixture extract Catalyst Vivatec 500 Axens HR 548 Axens HR 548 Axens HR 548 (TDAE) A1024 A1024 A1024 Reaction 310 330 350 temperature [ C.] Pressure 200 200 200 [bar] Residence time 18 18 16 [min] DMSO extract IP 346 2.6 2.8 2.9 2.8 [%] Benzo-(a)pyrene GC-MS 0.4 0.3 0.1 0.5 [ppm] Total PAH GC-MS 5.7 2.5 3.1 4.2 [ppm] Viscosity at DIN 51562 21.1 19.1 12.6 20.8 100 C. T. 1 [mm.sup.2/s] Sulfur DIN EN ISO 1.03 0.15 0.12 0.10 [%] 14596 CA DIN 51378 25 24 25 24 [%] CN DIN 51378 30 33 42 48 [%] CP DIN 51378 45 44 33 28 [%] AP DIN ISO 2977 70 70 64 61 [ C.]

(13) The process oils that were obtained were worked into compounds (rubber mixtures). The composition of the compounds can be seen from Table 3.

(14) TABLE-US-00003 TABLE 3 Composition of compounds Raw material Product, manufacturer Comparison Example 2a Example 2b Example 2c Buna VSL 5025-0 HM SSBR, Lanxess 70 70 70 70 Buna CB 24 NdBR, Lanxess 30 30 30 30 Ultrasil 7000 GR Silica, Evonik 80 80 80 80 SI 75 Silane, Evonik 5.8 5.8 5.8 5.8 Corax N 223 Soot, Evonik 10 10 10 10 Vulkanox 4020/LG 6PPD, Lanxess 1 1 1 1 Vulkanox HS/LG TMQ, Lanxess 1 1 1 1 Rotsiegel zinc white ZnO, Grillo 3 3 3 3 Stearic acid 1 1 1 1 Vulkacit D/C Sulfenamide, Lanxess 2 2 2 2 Vulkacit CZ/C Sulfenamide, Lanxess 1.5 1.5 1.5 1.5 Sulfur 1.8 1.8 1.8 1.8 Vivatec 500 TDAE oil, H&R 37.5 Hydrogenation 37.5 products from primary extract Hydrogenation 37.5 products from primary/secondary extract mixture Hydrogenation 37.5 products from secondary extract

(15) The compounds were vulcanized and the properties of the resulting vulcanizates were measured. These are given in Table 4.

(16) TABLE-US-00004 TABLE 4 Hardness, rebound elasticity, delta tangent and wear of resulting vulcanizates Comparison Example 2a Example 2b Example 2c Hardness Shore A hardness 60 62 61 61 A/D at 23 C. Standard Shore A hardness 59 59 60 54 at 70 C. Rebound R (23 C.) 33.5 32.2 31.5 30.8 elasticity R (70 C.) 55 54 55 57 Tensile test Breaking 440 425 405 385 Bar S2 elongation: Breaking stress: 18.5 18.1 17.9 17.6 Tangent C. 0.52 0.50 0.47 0.48 delta 60 C. 0.13 0.13 0.12 0.11 Wear DIN 53516 wear 102 105 108 109

(17) It turns out that through the hydrogenation of the said raw materials process oils are obtained that have values that are absolutely comparable to a TDAE. One can see that with an increase of the NAP content the rolling resistance (tangent delta @ 60 C.) becomes better with an increase of the NAP content, while wear and wet slip resistance (tangent delta @ 0 C.) become better with a decrease of the NAP content. This puts the user in a position to be able to adjust the said key properties selectively and not just in the case of tires. Such adjustment up to now was not possible with the traditional process oils.