GB2133417A - Processing thermally cracked oil distillates - Google Patents

Abstract

A hydrocarbon feed comprising a thermal-cracked oil distillate obtained from a process for thermal cracking of a petrolic heavy residual oil at a temperature of 400 DEG C to 700 DEG C, said distillate consisting mainly of hydrocarbons boiling in the range of 120 DEG to 290 DEG C and said distillate containing aliphatic olefins, is treated at a reaction temperature of 30 DEG to 300 DEG C in liquid phase in the presence of an acid catalyst, to obtain a reaction product having a boiling range which is higher than that of the hydrocarbons as the main component of the distillate and which is not lower than 260 DEG C.

Description

SPECIFICATION Method of processing thermal-cracked oil distillates Background of the invention The present invention relates to a method of processing a distillate from a thermal-cracked oil obtained in a thermal cracking process using a petrolic heavy residual oil as a starting material.

Recently, because of the exhaustion of petroleum resorces, heavier crude oils have come to be used, thus giving rise to an increasing tendency of the amount of heavy oils by-produced such as residual oils in distillations. These heavy residual oils are of less industrial value by reason of their high viscosities or high sulfur and metal contents.

On the other hand, such heavy residual oils can be utilized in thermal cracking processes typified by coking, which may be the only utilization mode of those oils. From the heavy residual oil coking process is obtained a liquid substance, i.e., thermal-cracked oil, as well as coke and gas. Usually, the yield of distillates from the cracked oil is fairly high and the distillates are obtained in large amounts.

Since the cracked oil distillates thus obtained in large amounts contain large amounts of unsaturated compounds and aliphatic hydrocarbons and do not have a sufficiently high octane number.

they have heretofore not been used directly as gasoline base stocks for automobiles, for which purpose they are required to be further subjected to a reforming treatment such as a fluid catalytic cracking. At most, the distillates have been used as mere fuels for boilers, etc. Therefore, how to utilize such large amounts of thermal-cracked oil distillates is becoming a subject of discussion in the industrial world.

Summary of the invention It is an object of the present invention to effectively utilize a distillate from a cracked oil obtained in a large amount as a by-product, for example, in the coking process which distillate has been found useful merely as fuel for boilers or the like, and to enhance the utilization value of heavy residual oils by-produced in large amounts typical of which is petroleum asphalt, by processing those oils.

It is another object of the present invention to effectively utilize a high-boiling aromatic hydrocarbon distillate of little utilization value by-produced from a cracking apparatus for the production of ethylene.

According to the present invention, a hydrocarbon feed which comprise a distillate from a thermal-cracked oil obtained by thermally cracking a petrolic heavy residual oil at a temperature not lower than 4000C and not exceeding 7000C is treated with an acid catalyst, whereby there is obtained a liquid reaction product which is industrially useful, for example, as an insulating oil and the material for surfactant. Moreover, if this reaction product is separated from the said distillate by a physical separation means such as distillation, the said distillate itself is reformed intoa distillate which contain reduced amounts of unsaturated compounds and which is useful as an industrial solvent, a starting material for the production of n-paraffin, etc.

In U.S. Patent No. 4,208,268 there is disclosed a process for treating a thermal-cracked byproduct oil distillate with an acid catalyst. However, this distillate is from a thermal cracking process for the preparation of lower olefins such as ethylene, and is rich in aromatics. Usually, heavy residual oils are not used as starting materials for such cracking. Besides, the cracking temperature is as high as not lower than 7O00C because lower olefins are to be produced.

Description of preferred embodiments The petrolic heavy residual oils referred to herein indicate bottom residues in atmospheric distillation, vacuum distillation and thermal or catalytic cracking, and various residues in petroleum refining, for example, residual oils in extraction with furfural, propane, pentane, etc., residual oils in reformers, as well as mixtures thereof, in the ordinary sense in the petroleum refining industry.

In the thermal cracking process of the present invention, the cracking temperature should be not lower than 4000C and should not exceed 7000C. If the cracking temperature is lower than 400 C, a thermal cracking will not occur, and if it exceeds 7000 C, regardless of the cracking time, the resultant thermal-cracked oil will contain excess aromatic hydrocarbons which per se are highly reactive, thus permitting an easy production of high polymers such as resins in the treatment with an acid catalyst, and the proportion of aliphatic olefins boiling in the range of 1200 to 2900C will become too small.

Therefore, such temperatures outside the above-defined temperature range are not desirable. A preferable cracking temperature range is from 4000 to 6000 C, more preferably from 4000 to 5500C.

The cracking time may vary, depending on the main purpose of the thermal cracking process such as, for example, the production of coke or the reduction in viscosity of the starting heavy oil. For example, the cracking time may be selected from the range of 10 seconds to 50 hours. The cracking may be performed in the presence of steam or other non-reactive gaseous medium. The cracking pressure usually is relatively low, that is, ranging from vacuum to 50 kg/cm2 or so.

As typical examples of such thermal cracking process for heavy residual oils, mention may be made of the viscosity breaking process and the coking process, as described in the "Hydrocarbon Processing", Vol. 61, No. 9 (September 1982), pp. 1 60-1 63.

The viscosity breaking process is a thermal cracking process mainly for lowering the viscosity of a feed material which is carried out under relatively mild cracking conditions while suppressing the formation of coke in a tubular heating furnace. Usually, the cracked oil leaving the cracking furnace is quenched for suppressing the formation of coke. As concrete processes are included the Lummus process and Shell process.

In the coking process, which is a coke producing process, are included the delayed coking process (e.g, UOP process, Foster Wheeler process, M. W. Kellogg process, Lummus process and CONOCO process) in which the residual oil is once heated in a heating furnace for a relatively short time and then fed to a coke drum for forming an agglomerate coke over a relatively long period of time; the fluid coking process (e.g. Exxon process) in which the residual oil is thermally cracked over a hightemperature fluid coke; the flexicoking process (Exxon process) which comprises the combination of the fluid coking process with the resultant coke gasifying process; and the Eureka process which carries out not only a thermal cracking but also steam stripping at a relatively low pressure such as atmospheric pressure to prepare pitch.

Of the thermal cracking processes referred to above, the coking process is preferred because the sulfur and metal components in the residual oil are concentrated into the resultant coke so the content of these impurities in the cracked oil is relatively small and therefore the refining even after the acid catalyst treatment is relatively easy and also because the content of high-boiling aliphatic olefins is relatively large. Above all, the delayed coking process has been adopted on large scales because an agglomerate coke is obtained which is useful as a carbon source of graphite for electrode, etc. Since the delayed coking process affords a very large amount of cracked by-product oil, if it is utilized effectively by the present invention, it will bring about a great advantage.

The compositions of the thermal-cracked oils obtained by the above-described thermal cracking processes differ according to types of the processes, thermal cracking conditions, kinds of the starting heavy oils, etc. Usually, however, those thermal-cracked oils, which scarcely contain aromatic olefins, mainly contain reactive aliphatic olefins such as n-olefins and iso-olefins in addition to n-paraffins and iso-paraffins, and further contain aromatic hydrocarbons having an alkyl-substituted single ring such as alkylbenzenes, having an alkyl-substituted composite ring such as alkylindanes and alkyltetralins and having an alkyl-substituted condensed ring such as alkylnaphthalenes.

Among the distillates from the thermal-cracked oils obtained in the above-described thermal cracking processes, the distillates to be processed in the present invention are those which consist mainly of hydrocarbons boiling in the range of 1200 to 2900C, preferably 1 SOC to 2600C and which contain aromatic hydrocarbons and at least 10 wt.%, preferably at least 1 5 wt.%, of aliphatic olefins.

Distillates consisting mainly of hydrocarbons whose boiling range is outside the above-defined range cannot afford industrially useful liquid reaction products, and with distillates containing less than 10 wt.% of aliphatic olefins, it is impossible to recover reaction products in economical yields. Therefore, both such distillates are not desirable.

A typical composition of the distillates which may be used in the invention is 30-70 wt.% paraffins, 10-40 wt.% aliphatic olefins and 5-20 wt.% aromatic hydrocarbons. However, as long as the above-mentioned conditions required of the distiilates are satisfied, the thermal-cracked oils may be subjected to fractionation or diluted with unreacted oils recovered after acid treatment.

According to the processing method of the present invention, in addition to the treatment of the thermal-cracked oil distillate itself with an acid catalyst, a hydrocarbon feed comprising a mixture of such thermal-cracked oil distillate and a distillate or distillates containing various aromatic hydrocarbons may be treated in the same manner, whereby there is obtained a liquid reaction product having useful properties, for example, having a superior fluidity at low temperatures.

More specifically, the thermal-cracked oil distillate may be mixed with one or more distillates boiling in the range of 150" to 2800 C, preferably 1 500 to 2500C, selected from the group consisting of (a) a distillate from a thermal-cracked by-product oil obtained by thermally cracking a petrolic light oil at a temperature of 7500 to 8500 C, (b) a reformate distiilate obtained by a catalytic reforming of a petrolic light oil boiling in the range of 500 to 2500C and (c) an aromatic distillate consisting mainly or aromatic hydrocarbons separated from the thermal-cracked by-product oil distillate of the above (a) and/or the reformate distillated of the above (b).

Further, if the thermal-cracked oil distillate is mixed with aromatic hydrocarbons boiling below 1 500C such as benzene, toluene, xylene and ethylbenzene, there will be obtained a useful liquid reaction product.

The thermal-cracked by-product oil distillate of the above (a) is obtained when a petrolic light oil is thermally cracked at a temperature of 7500 to 8500C with a view to producing lower olefins such as ethylene and propylene.

As examples of the petrolic light oil there are mentioned naphtha, kerosene, light oil, LPG and butane. In consideration of properties of the resultant thermal-cracked by-product oil, naphtha, kerosene and light oil are preferred as starting materials in the thermal cracking because those oils are more suitable for the objects of the present invention.

The method of thermal cracking is not specifically limited. Various conventional thermal cracking methods carried out in the temperature range of 7500 to 8500 C, for example, the method using a tubular cracking furnace and the method using a heat-transfer medium, can be adopted.

The thermal-cracked by-product oil distillate obtained from the thermal-cracked product after removal of the object products which are olefins, diolefins, etc. such as ethylene, propylene and butadiene, which distillate differs depending on the kind of the starting petrolic light oil and thermal cracking conditions, is a distillate having 6 to 10 carbon atoms, containing relatively large amounts of aromatic hydrocarbons and containing 2-1 0 wt.% paraffins, 3-1 0 wt.% naphthenes, 55-85 wt.% aromatic hydrocarbons, 2-10 wt.% aliphatic olefins and 2-1 5 wt.% aromatic olefins, of which the distillate boiling in the range of 1 500 to 2800C may be mixed with the thermal-cracked oil distillate in the present invention.

The reformate distillate of the above (b) is obtained by a catalytic reforming of a petrolic light oil boiling in the range of 50" to 280"C, e.g. a straight-run naphtha. Catalytic reforming has been widely conducted in the fields of petroleum refining and petrochemistry for improving the octane number or for obtaining benzene, toluene, xylene, etc. It is carried out using an alumina or silica-alumina supported metal catalyst such as platinum, platinum-rhenium, molybdenum oxide or chromium oxide.

As industrial methods, mention may be made of the Platforming of UOP Co. which is a fixed bed type and the Ultraforming of Standard Oil Co. which is also a fixed bed type. In addition fiuidized bed type and moving bed type catalytic reforming methods are also employable. In the catalytic reforming, there mainly occur dehydrogenation and cyclization reaction, as well as isomerization reaction; as a result, the BTX (benzene, toluene and xylene) content increases and the octane number is improved. However, the resultant reformate has a bromine number not more than about 3.8 and thus contains very small amounts of unsaturated components.

The catalytic reformate distillate typically has 6 to 10 carbon atoms and contain 30-35 wt.% paraffins, 65-70 wt.% aromatic hydrocarbons and 0--2 wt.% olefins. The catalytic reformate distillate which may be used in the present invention has a boiling range of 1 500 to 2800 C.

Further, the aromatic distillate of the above (c), which consists mainly of aromatic hydrocarbons, is obtained from the aforementioned catalytic reformate distillate, thermal-cracked by-product oil distillate and mixtures thereof by the use of a suitable physical separation. This separation has been performed on a large scale in the petrochemical field for obtaining BTX from catalytic reformate oils, thermal-cracked by-product oils and mixtures thereof usually according to the solvent extraction process or extractive distillation process. As typical examples of the solvent extraction process are mentioned Udex process (Dow process) which employs diethylene glycol or triethylene glycol as the extraction solvent and Sulfolane process (Shell process) which employs sulfolane as the extraction solvent.Usually, this extraction is preceded by hydrogenation to remove unsaturated components for preventing the apparatus from being blocked by polymerization of the unsaturated components.

The aromatic distillate (c) consisting mainly of aromatic hydrocarbons thus separated from the catalytic reformate distillate, the thermal-cracked by-product oil distillate and mixtures thereof consists of C9 to C10 hydrocarbons and has a boiling range of 1 500 to 2800 C. It contains alkylbenzenes, polyalkylbenzenes, naphthalene and many other aromatic hydrocarbons. However, the distillate of this boiling range has heretofore not been utilized effectively although it is obtained in a large amount together with the BTX distillate.

As to the mixing ratio, 20-95 wt.% of the thermal-cracked oil distillate from the residual oil may be mixed with 80-5 wt.% of the distillate (a), (b) and/or (c), or with 80-5 wt.% of aromatic hydrocarbons boiling lower than 1500 C. A proportion of the thermal-cracked oil distillate smaller than 20 wt.% is not desirable because the yield of the reaction product would become lower. A preferable mixing ratio is 70-90 wt.% of the thermal-cracked oil distillate and 30-1 0 wt.% of the distillate (a), (b) and/or (c) or the lower aromatic hydrocarbons.If the alkyl-benzene content of the reaction product is to be increased, it is recommended to use the thermal-cracked oil distillate from the residual oil in a relatively small amount, e.g. 25-60 wt.%, and use 75-40 wt.% of the others.

In the process of the present invention, a hydrocarbon feed comprising the thermal-cracked oil distillate from the residual oil is treated at a reaction temperature of 300 to 3000C in liquid phase in the presence of an acid catalyst to obtain a reaction product having a boiling range which is higher than that of said thermal-cracked oil distillate, and which is not lower than 2600 C.

Preferred examples of the acid catalyst are solid acid catalysts, mineral acids, so-called Friedel Crafts catalysts and organic acids. More concrete examples include solid acid catalysts such as acid clay minerals such as acid clay and activated clay, amorphous or crystalline silica-alumina, AIF3 . Al2O3 and strong acid type ion-exchange resins; Friedel-Crafts catalysts such as HF, AICI3, BF3 and SnCI4; and inorganic and organic acids such as sulfuric acid, p-toluenesulfonic acid and trifluoromethanesulfonic acid.

The reaction may be carried out according to any of the batch process, semi-batch process and flow process. But, in the case of using a solid acid, the flow process is preferred.

The acid catalyst is used in an amount of 0.2 to 20 wt.%, preferably 1 to 10 wt.%, based on the weight of the hydrocarbon feed in the batch process. In the flow process, it is treated at a liquid hourly space velocity (LHSV) of 0.1 to 20, preferably 0.5 to 10. The reaction temperature is in the range of 300 to 3000 C, preferably 500 to 2500 C. The treating time, which differs according to reaction conditions such as the amount of catalyst, reaction temperature and the feed composition, should be long enough to complete the reaction, and usually it is selected from the range of 2 to 24 hours. The reaction pressure is not specifically limited if only it can maintain the reaction system in liquid phase.

The acid catalyst treatment is performed so as to give a reaction product having a boiling range not lower than 2600C, and which is higher than the boiling range of the thermal-cracked oil distillate.

The reaction product consists mainly of oligomers of aliphatic olefins and alkylates of aliphatic olefins with aromatic hydrocarbons. In the case where the feed is a mixture containing an excess distillate which contains aromatic hydrocarbons, the resultant reaction product consists mainly of alkylbenzene as alkylate. If the boiling range of the reaction product is lower than 26O0C or lower than the boiling range of the thermal-cracked oil distillate, the reaction product will be of no industrial value, and the effect of the acid catalyst treatment cannot be expected.

In the present invention, as described above, since the specific distillate from the specific source is used as a feed material and subjected to the specific treatment, a high molecular weight compound which badly affects physical properties is substantially not produced, and the reaction product obtained is a liquid product having a relatively low viscosity, for example, in the range of 3 to 30 cSt at 750C.

Therefore, after the acid catalyst treatment, unreacted distillate (the starting thermal-cracked oil distillate), and unreacted other distillate or lower aromatic hydrocarbons which are mixed to said thermal-cracked oil distillate, are separated by a physical separation such as distillation, and then the reaction product can be put to practical use without the necessity of further separating heavier compounds. Of course, the reaction product may be divided into fractions of suitable boiling ranges according to purposes of use, etc.

As a result of the above-mentioned treatment, the content of unsaturated component of the thermal-cracked oil distillate is reduced, for example, the bromine number thereof is decreased, but the reaction product contains, particularly on its relatively high-boiling side, oligomers of aliphatic olefins as previously noted, so it is preferable that the content of unsaturated components be decreased or made zero by a catalytic hydrogenation treatment. This catalytic hydrogenation treatment may be applied to any of the separated reaction product, distillate which contains a large amount of the reaction product and the thermal-cracked oil distillate itself which has been subjected to the acid catalyst treatment.

In the catalytic hydrogenation treatment there may be used any conventional catalyst. For example, metallic catalysts such as Pt, Pd, Ni, Co, Mo, W, Co-Mo and Ni-W are employable. The catalytic hydrogenation treatment is carried out usually under the conditions of a reaction temperature in the range of 250 to 4000 C, a hydrogen pressure in the range of 20 to 100 kg/cm2, a hydrogen/oil mole ratio in the range of 0.5 to 20 and an LHSV in the range of 0.1 to 10.

After the catalytic hydrogenation treatment, the hydrogenated reaction product, and gases if required, are separated by any suitable means such as distillation. Of course, the hydrogenated reaction product may be further separated into fractions according to purposes of use. The reaction product or the hydrogenated reaction product thus obtained has a boiling range not lower than 2600 C, a kinetic viscosity not higher than 30 cSt at 750C, a pour point not higher than -450C and a flash point not lower than 1400 C. As to its composition, although the quantitative relation varies, depending on the kind of the starting petrolic heavy oil, thermal cracking conditions and the blending ratio of the aromatic distillate, the hydrogenated reaction product which scarcely contains n-paraffins, contains iso-paraffins and aromatic hydrocarbons containing alkyl-substituted single or composite rings.

The reaction product thus obtained has a good color and a reduced content of impurities such as sulfur and metal. It is sufficiently employable in almost all of the conventional uses of high-boiling hydrocarbon oils, for example, as a lubricating oil, insulating oil, rubber processing oil, a special solvent for medicines, agricultural chemicals and dyes, a solvent for inks, paints and plastics, a plasticizer and a diluent. And, suiphonated reaction products by ordinary method are useful as surface active agents.

Moreover, after separation of the above reaction product from the processed thermal-cracked oil distillate, the remaining unreacted thermal-cracked oil distillate itself has a reduced content of olefins and aromatic hydrocarbons and an increased content of n-paraffins. This indicates that the reforming of the thermal-cracked oil distillate is attained. Therefore, this unreacted thermal-cracked oil distillate itself is best suited as a n-paraffinic hydrogen solvent for paints, medicines, agricultural chemicals and dyes.

Further, since the distillate is rich in relatively high-boiling n-paraffins, it is suitable as a starting material for the production of n-paraffins using a physical separation means such as a molecular sieve or a urea adduct process. The thus separated n-paraffins are employable as starting materials for the preparation of chlorinated paraffins, soft type alkylbenzenes and higher alcohols.

The following examples are given to further illustrate the present invention.

Example 1 From a delayed coking apparatus (cracking conditions: temperature of 4960C, residence time of 24 hours, pressure of 4 kg/cm2) for coking a residual oil in vacuum distillation of such properties as shown in Table 1 obtained from Minas crude oil there was obtained a thermal-cracked oil in addition to gases and coke as shown in Table 2. The feed distillate used from this thermal-cracked oil was of such a composition as shown in Table 3.

Table 1 Properties of the heavy residual oil

Minas vacuum-distilled bottom residue Specific gravity @ 15 C), API 20 Asphaltene, wt.% 2.6 Conradson residual carbon, wt.% Table 2 Yield (wt.O

Starting oil 100 Butane and light gas 8 31 600C (Distillate No. 1) 13 160-260 C (Distillate No.2) 22 260"C+ (Distillate No.3) 40 Coke 17 Table 3 Feed composition

Distillate No. 2) 1 160-260 C Bromine number, cg/g | 202 Type analysis (wt.%) Paraffins 1 683 | n-Paraffins 31.7 sso-paraffins 36.6 Aliphatic olefins 1 19.4 Aromatics 12.3 Aromatic olefins Then, 40 g. of AlCl3 was added to 4 1 of distillate No. 2 followed by treatment at 500C for 20 hours according to the batch process.Thereafter, the reaction mixture was treated with aqueous ammonia for neutralization and decomposition of AlCl3, which was removed by washing with water.

Subsequent dehydration afforded a reaction product (870 g., 29% yield) as a 3400C+ distillate. This reaction product was found to have a bromine number of 6.4 cg/g and an aromatics content of 78.7%, most of the balance was olefins.

Unreacted distillate after removal of the reaction product from the processed distillate No.2 had a good color, a bromine number of 0.80 cg/g, an n-paraffins content of 44% and an aromatics content as small as 3.3%. In view of the reduced content of aromatics and olefins and increased content of n paraffins, it is seen that reforming has been attained. Therefore, the unreacted distillate is employable as a superior aliphatic hydrocarbon solvent or as a starting material for the production of n-paraffins, after a simple hydrogenation refining if required.

The reaction product was then subjected to a hydrogenation treatment using a Co-Mo catalyst under the conditions of a hydrogen pressure of 50 kg/cm2, a reaction temperature of 2800C and one volume feed oil/catalyst volume/hr.

After the hydrogenation, the light fraction formed by decomposition was distilled off, and the hydrogenated reaction products was recovered. The percent recovery was 92%. It proved to have a bromine number of 0.34 cg/g and an aromatics content of 76.6%.

Table 4 below shows physical properties of the hydrogenated reaction product as well as results of electrical characteristic tests conducted in accordance with ASTM D-1 934 and oxidation stability tests conducted in accordance with JIS C2101. Results obtaining using mineral oil are also set out in the same table for comparison. From the results shown in Table 4 it is apparent that the hydrogenated reaction product has superior physical properties even in comparison with the mineral oil and is therefore very suitable as an insulating oil or a lubricating oil.

Table 4

Hydrogenated reaction Mineral product oil Kinetic Viscosity (Ga 750C, cST) 10.2 3.1 Pour Point (OC) -47.5 -30 Flash Point (OC) 202 132 Electrical characteristics (heat deterioration) Dielectric loss tangent (%, (By 80 C) Before deterioration 0.001 0.001 After deterioration 0.015 0.194 (without catalyst) After deterioration 0.066 2.323 (with catalyst) Volume resistivity (Qcm, @ 800 C) Before deterioration 3.7x1016 6.3x1015 After deterioration 2.1x1014 2.5 x 1013 (without catalyst) After deterioration 9.6x1013 1.3x1012 (with catalyst) Oxidation Stability Sludge (%) 0.04 0.10 Total acid number 0.12 0.50 (mgKOH/g) Example 2 40 ml. of BF3.H20 was added to 4 1 of distillate No. 2 in Table 2 obtained in Example 1 followed by treatment at 5O0C for 2 hours according to the batch process. Then, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which was removed by washing with water. After a sufficient dehydration, 690 g. of reaction product was recovered as a 35O0C+ distillate. The reaction product proved to have a kinetic viscosity of 10.2 cSt ((Z 750C), a pour point of -47.50C and a flash point of 2000 C.

Example 3 The Minas vacuum-distilled bottom residue described in Example 1 was subjected to a thermal cracking under the conditions of a temperature of 4850 C, a pressure of 1.5 kg/cm2 and a residence time of 1.5 hours. The resultant thermal-cracked oil was rectified to obtain a thermal-cracked oil distillate having a boiling range of 1000 to 3000C (containing 85% components boiling in the range of 1200 to 2900 C). The yield was 37%.

The thermal-cracked oil distillated was treated using a silica-alumina catalyst according to the fixed-bed flow process under the conditions of a reaction temperature of 2000C and one volume feed oil/catalyst volume/hr. The reaction solution was subjected to a catalytic hydrogenation treatment using a Co-Mo catalyst under the conditions of a hydrogen pressure of 50 kg/cm2, a reaction temperature of 3000 C, one volume feed oil/catalyst volume/hr and an H2/oil mole ratio of 10, to obtain a hydrogenated reaction product having a boiling range beyond 3300C, a kinetic viscosity of 5.4 cSt (( 750C), a pour point of -52.50C and a flash point of 1 520 C.

Unreacted thermal-cracked oil distillate after removal of the reaction product scarcely contained aromatics, unsaturated components and sulfur, and it had good odor and color. Thus, it proved to be best suited for use as an aliphatic hydrocarbon solvent.

The catalytically hydrogenated reaction product was tested for electrical characteristics and oxidation stability in the same way as in Example 1. As a result, there were obtained about the same values as in Example 1.

Example 4 A by-product oil distillate having a boiling range of 61 0 to 2500C was distilled out from a tubular thermal cracking furnace for thermal cracking of naphtha at 7800 to 81 00C for the production of ethylene and propylene. The by-product oil distillate contained large amounts of aromatic hydrocarbons such as benzene, toluene, xylene and styrene in addition to acetylenes and diolefins.

Then, the distillate was subjected to a hydrogenation treatment using a Unifining two-stage hydrogenation apparatus for the removal of unsaturated components such as diolefins and for desulfurization. As a catalyst there was used a cobalt-molybdenum catalyst supported on alumina. The hydrogenation conditions were a temperature of 2200C and a pressure of 50 kg/cm2 in the first stage and 3300C and 50 kg/cm3 in the second stage.

The thermal-cracked by-product oil distillate thus hydrogenated proved to have a sulfur content of 0.01% and an unsaturated components content not higher than 0.01%. This distillate will be hereinafter referred to as distillate (a).

In the next place, a reformate was obtained from a Plafforming apparatus for a catalytic reforming of naphtha having a boiling range of 500 to 2500C by the use of a platinum catalyst in the presence of hydrogen at a reaction temperature of 4700C and pressure of 50 kg/cm2 for the production of gasoline and benzene, toluene or xylene. This reformate also contained large amounts of aromatics, but had a less content of unsaturated components than that of the foregoing thermal-cracked by-product oil distillate. It will hereinafter be referred to as distillate (b).

Then, 90 vol.% of the reformate distillate (b) having a boiling range of 600 to 25O0C was mixed with 10 vol.% of a fraction having the same boiling range from the distillate (a) (thermal-cracked byproduct oil distillate), and the mixture was fed to a Udex extractor to recover an aromatics distillate.

More specifically, the mixture was fed to the middle portion of an aromatics extraction column, while ethylene glycol as an extraction solvent was fed from the top of the column, and thus a countercurrent extraction was performed. After refining of the extract, there were produced benzene, toluene, xylene and ethylbenzene by fractionation. At this time, an aromatic distillate having a boiling range of 150 to 2500C was by-produced as a distillate of C9 or more. This aromatics distillate, containing 99% or more aromatics, will be hereinafter referred to as distillate (c). Table 5 below shows properties of a fraction (distillate (c')) having a boiling range of 1600 to 1 800C from the distillate (c).

Table 5

Boiling range 1600--1800C Properties (distillate (c')) Specific gravity @ 600F/600F 0.876 Saybolt color above +30 Flash point (PMCC) 45 Blended aniline point, 0C 13 Aromatics (vol.%) 99.5 Distillation property (ASTM) Initial boiling point, OC 1 60 Dry point, OC 176 Table 6 below shows the composition of the thus-extracted xylene distillate (c") having a boiling range of 1350 to 1450C.

Table 6 Composition of xylene distillate (c)

Component name Mixing ratio Ethylbenzene 55.8 wt.% p-Xylene 10.4 wt.% m-Xylene 20.7 wt.% o-Xylene 11.8 wt.% Others 1.3 wt.% 5 g. of AICI3 was added to a mixture (containing 1 7.5% aliphatic olefins) consisting of 450 ml. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 50 ml. of the distillate (c) (aromatics distillate) followed by treatment at 1 850C for 1.5 hours according to the batch process.

Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization and decomposition of AIR13. Subsequent dehydration afforded 98.4 g. (24.4% yield) of reaction product as a 31 50C+ distillate. The reaction product proved to have a bromine number of 5.6 cg/g and an aromatics content of 80.2%. The balance were almost olefins. Further, the reaction product was found to have a kinetic viscosity of 10.4 cSt (@ 750C), a pour point of -47.50C and a flash point of 1800 C.

Then, the reaction product was subjected to a hydrogenation treatment using a Co-Mo catalyst under the conditions of a reaction temperature of 26O0C, a hydrogen pressure of 50 kg/cm2 and one volume reaction mixture/catalyst volume/hr. Thereafter, the light fraction formed by decomposition was distilled off and the hydrogenated reaction product was recovered at a percent recovery of 81.1%.

The reaction product thus hydrogenated had a bromine number of 0.3 cg/g and an aromatics content of 78.5%.

Table 7 shows physical properties of the hydrogenated reaction product as well as results of electrical characteristic tests conducted in accordance with ASTM D-1 934 and oxidation stability tests conducted in accordance with JIS C21 02. From the results shown in Table 7 it is apparent that the hydrogenated reaction product obtained according to the process of the present invention has superior physical properties as compared with mineral oil and is therefore best suited for use as an insulating oil or a lubricating oil.

Table 7 Kinetic Viscosity (@ 75cC, cSt) 9.1 Pour point ( C) -47.5 Flash point(OC) 180 Electrical characteristics (heat deterioration) Dielectric loss tangent (%, @ 800C) Before deterioration 0.001 After deterioration (without catalyst) 0.017 After deterioration (with catalyst) 0.066 Volume resistivity (cm, @; 800C) Before deterioration 7.0x1016 After deterioration (without catalyst) 3.2x 1014 After deterioration (with catalyst) 1 Ox 1 owl4 Oxidation Stability Sludge (%) 0.05 Total acid number (mgKOH/g) 0.11 Example 5 5 g. of AICI3 was added to a mixture (containing 18.4% olefins) consisting of 475 ml. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 25 ml. of the distillate (c') (aromatics distillate) followed by treatment at 1 850C for 1.5 hours according to the batch process.

Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which catalyst was removed by washing with water. After a sufficient dehydration there was obtained 96.4 g. (24.0% yield) of reaction mixture as a 315 C+ distillate. This product proved to have a kinetic viscosity of 10.6 cSt (@ 75cC), a pour point of --47.5 OC and a flash point of 180 C. Electrical characteristics and oxidation stability of the product after refining by hydrogenation were of about the same values as in Example 1.

Example 6 5 g. of AICI3 was added to a mixture (containing 9.7% olefins) consisting of 250 ml. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 250 ml. of the distillated (c') (aromatics distillate) followed by treatment at 1 850C for 1.5 hours according to the batch process.

Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which catalyst was removed by washing with water. After a sufficient dehydration there was obtained 43.2 g. (10.4% yield) of reaction mixture as a 315 C+ distillate. This product proved to have a kinetic viscosity of 6.5 cSt (@ 75cC), a pour point of50 C and a flash point of 180 C.

Example 7 5 g. of AICI3 was added to a mixture (containing 4.0% oiefins) consisting of 1 00 mi. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 400 ml. of the distillate (c') (aromatics distillate) obtained in Example 4 followed by treatment at 185 for 1.5 hours according to the batch process. Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which catalyst was removed by washing with water. After a thorough dehydration there was obtained 97.2 g. (24.3% yield) of reaction mixture as a 315 C+ distillate. This product proved to have a kinetic viscosity of 1 1.6 cSt ((6 75cC), a pour point of 42.5cm and a flash point of 190 C.

Example 9 5 g. of AICI3 was added to a mixture (containing 1 8.7% olefins) consisting of 450 ml. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 50 ml. of a fraction having a boiling range of 1 soc to 2500C from the distillate (a) (thermal-cracked by-product oil distillate) obtained in Example 4 followed by treatment at 1 850C for 1.5 hours according to the batch process.

Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which catalyst was removed by washing with water. After a thorough dehydration there was obtained 97.2 g. (24.1% yield) of reaction mixture as a 315 C+ distillate. This product proved to have a kinetic viscosity of 12.1 cSt, a pour point of 42.5cm and a flash point of 1 86cC.

Example 10 5 g. of AlCí3 was added to a mixture (containing 1 7.8% olefins) consisting of 450 ml. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 50 ml. of a fraction having a boiling range of 1 soc to 2500C from the distillate (b) (reformate distillate) obtained in Example 4 followed by treatment at 1 850C for 1.5 hours according to the batch process. Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which catalyst was removed by washing with water. After a thorough dehydration there was obtained 95.3 g. (23.6% yield) of reaction mixture as a 315 C+ distillate.This product proved to have a kinetic viscosity of 11.6 cSt, a pour point of -450C and a flash point of 1 90cC.

Example 11 5 ml. of BF3 . H20 was added to a mixture (containing 1 7.5% olefins) consisting of 450 ml. of the distillate No.2 (thermal-cracked oil distillate) obtained in Example 1 and 50 ml. of the distillate (c') (aromatic distillate) obtained in Example 4 followed by treatment at 900C for 5 hours according to the batch process. Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which catalyst was removed by washing with water. After a thorough dehydration there was obtained 72 g. (17.8% yield) of reaction product as a 315 C+ distillate.This product proved to have a kinetic viscosity of 7.2 cSt (@ 75"C), a pour point of --50"C and a flash point of 180 C.

Example 12 The Minas vacuum-distilled bottom residue described in Example 1 was thermally cracked under the conditions of a temperature of 485 cC, a pressure of 1.5 kg/cm2 and a residence time of 1.5 hours, and the resultant thermal-cracked oil was rectified to obtain a thermal-cracked oil distillate having a boiling range of 1 ooc to 300"C (containing 85% components boiling in the range of 120 to 290cC).

The yield was 37%.

A mixture (containing 1 8.0% olefins) consisting of 450 ml. of the thermal-cracked oil distillate just obtained above and 50 ml. of the distillate (c') (aromatics distillate) obtained in Example 4 was treated using a silica-alumina catalyst according to the fixed-bed flow process under the conditions of a reaction temperature of 200"C and one volume feed oil/catalyst volume/hr.

The reaction solution was subjected directly to a catalytic hydrogenation treatment under the conditions of a reaction temperature of 300cC, a hydrogen pressure of 50 kg/cm2, one volume feed oil/catalyst volume/hr and an H2/oil mole ratio of 10, to obtain a reaction product as a 315 C+ distillate having a kinetic viscosity of 5.2 cSt (@ 75cC), a pour point of --52.5 OC and a flash point of 1 60cC.

Unreacted light distillate after removal of the reaction product scarcely contained unsaturated components and sulfur, and it had good odor and color.

Then, the hydrogenated reaction product was tested for electrical characteristics and oxidation stability. As a result, there were obtained about the same values as in Example 4.

The results obtained in Examples are tabulated below as Table 8 with respect to viscosity, pour point, flash point, etc.

Table 8

Example No. 4 5 6 Distillate of thermal-cracked oil distillate (distillate No. 2) (A) from thermal cracking of vacuum-distilled bottom residue Feed Distillate of aromatics distillate (distillate (c')) having Composi- (B) a boiling range of 160-1 800C obtained by tion solvent extraction Proportion of 10 5 50 (B) (vol.%) Reaction conditions AlCI3 1.3 wt.% I85cCxi.5 hr.

Yield (%) 24.4 24.0 10.4 Reaction Kinetic Viscosity 10.4 10.6 6.5 (cSt, @ 750C) Product Pour point ( C) -47.5 -47.5 -50 Flash point ( C) 180 180 180 Table 8 (contd.)

Example No. 7 8 9 Distillate of thermal-cracked oil distillate (distillate No. 2) (A) from thermal cracking of vacuum-distilled bottom residue Feed Distillate of aromatics aromatics thermal Composi- (B) distillate distillate cracked tion (distillate having a by-product (c')) having boiling oil a boiling range of distillate range of 1 50-2500C (distillate (a)) 160-180 C (distillate (c)) obtained by solvent extraction Proportion of 80 10 10 (B) (vol.%) Reaction conditions AlCI3 1.3 wt.% 1850CX1.5 hr.

Yield (%) 6.4 24.3 24.1 Kinetic Viscosity 4.0 11.6 12.1 Reaction (cSt, @ 75cC) Product Pour point -50 -42.5 -42.5 (0C) Flash point 180 190 186 ( C) PMCC Table 8 (contd.)

Example No. 10 11 12 Distillate of thermal-cracked oil distillate thermal-cracked (A) (distillate No. 2) from thermal oil distillate cracking of vacuum-distilled at a short bottom residue residence time Feed Distillate reformate same as same as Composi- of (B) distillate Example 4 Example 4 tion having a boiling range of 15O2500C (distillate (b)) Proportion of 10 10 10 (B) (vol.%) Reaction conditions AICI3 BF3. H20 fixed-bed flow wt.% flow process 185 Cx1.5 hr 1.0 vol.% silica-alumina Yield (%) 23.6 17.8 Reaction Kinetic viscosity 11.6 7.2 5.2 (cst, @ 75 C) Product Pout point -45 -50 -52.5 (cC) Flash point 190 180 160 ( C) PMCC Example 13 8.4 g. of anhydrous aluminum chloride was added to a mixture (containing 7.4% olefins) consisting of 400 ml. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 600 ml. of the xylene distillate (c") obtained in Example 4 followed by treatment at 1 300C for 1 hour according to the batch process. Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization and decomposition of the catalyst.Subsequent dehydration afforded 79.4 g. (9.5% yield) of reaction product as a 260cC+ distillate. The reaction product proved to have a bromine number of 1.0 cg/g and an aromatics content of 98%. Most of the balance were olefins. Further, this product had a kinetic viscosity of 5.3 cSt (@ 75 cC), a pour point of 50C and a flash point of 1 72cC.

Example 14 8.4 g. of anhydrous aluminum chloride was added to a mixture (containing 7.4% olefins) consisting of 400 ml. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 600 ml. of benzene followed by treatment at 800C for 1 hour according to the batch process.

Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which catalyst was removed by washing with water. After a thorough dehydration there was obtained 72.7 g. (8.7% yield) of reaction product as a 260cC+ distillate having a kinetic viscosity of 5.7 cSt (Ga 75cC), a pour point of -50 C and a flash point of 1 54cC.

Example 15 8.4 g. of anhydrous aluminum chloride was added to a mixture (containing 18.4% olefins) consisting of 950 ml. of the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 and 50 ml. of benzene followed by treatment at 100 C for 1 hour according to the batch process.

Thereafter, the reaction mixture was treated with an aqueous ammonia for neutralization of the catalyst, which catalyst was removed by washing with water. After a thorough dehydration there was obtained 192 g. (23.9% yield) of reaction product as a 260cC+ distillate having a kinetic viscosity of 13.1 cSt (@ 75cC), a pour point of --42.50C and a flash point of 1 64cC.

Example 16 300 ml. of benzene and 600 ml. of anhydrous hydrogen fluoride (purity: 99% or higher) were charged into a batch process reactor (content volume 5 1) cooled at 5 C and allowed to cool sufficiently with stirring, then a mixture consisting of 300 ml. of benzene and 400 ml. of the fraction having a boiling range of 1 60-2200C from the distillate No. 2 (thermal-cracked oil distillate) obtained in Example 1 was added dropwise over a period of 10 minutes. The stirring was continued for another one hour. Thereafter, the reaction mixture was allowed to stand for separation into oil layer and anhydrous hydrogen fluoride layer.Then, the oil layer was treated with a 10 wt.% potassium hydroxide solution for neutralization and decomposition of the anhydrous hydrogen fluoride incorporated therein, which hydrogen flouride was removed by washing with water. After a thorough dehydration there was obtained 85.3 g. (10.2% yield) of reaction product having a boiling range beyond 260cC, a kinetic viscosity of 3.5 cSt (@ 75cC), a pour point of below -550C and a flash point of 1440 C.

(Surfactant test) From the reaction product (unhydrogenated product) thus obtained, a distillate having a boiling range of 260 to 3300C was recovered at a percent recovery of 88.1% and the distillate was subjected to a sulfonation reaction.

Surfactant tests were conducted on the sulfonate thus obtained.

That is, 95.1 g. of the above distillate of 2600 to 3300C was placed in a 500 ml. glass vessel and 1 9 ml. of anhydrous sulfuric acid was blown therein together with nitrogen gas for 1 hour while vigorously stirring at 50 C to take place the sulfonation reaction. After completion of the sulfonation, the reaction mixture was gradually added into 148.2 g. of a 6.7% sodium hydroxide solution to be neutralized to pH 7.0-7.5. The amount of the added reaction mixture was 81.1 g. The yield of the sulfonated product was 84.4%.

Then, the sodium sulfonate was tested for surfactant characteristics.

That is, under the conditions set forth in Table 9, 0.2 part of the sodium sulfonate obtained above was dissolved in 1.5 parts of water, 70 parts of heavy oil B was thoroughly mixed therewith and 30 parts of fine carbon powder was thoroughly mixed therewith. Then, the mixture was allowed to stand and the sedimentation velocity of fine carbon powder was determined. As a result, even after the lapse of 50 days, the sedimentation was not recognizable.

When the sodium sulfonate was not used, fine carbon powder was immediately settled.

Table 9

Fine carbon powder used 85% passed through 200 mesh Heavy Oil B 90 cp @ 280C, 17cp@700C Concentration of fine 30 wt.% carbon powder Measuring temperature 300C

Claims (10)

Claims

1. Method of processing a hydrocarbon feed, characterized by treating said hydrocarbon feed at a reaction temperature in the range of 30 to 3000C in liquid phase in the presence of an acid catalyst, said hydrocarbon feed comprising a distillate from a thermal-cracked oil obtained in a thermal cracking process for thermally cracking a petrolic heavy residual oil at a temperature not lower than 4000C and not exceeding 7000 C, said distillate consisting mainly of hydrocarbons boiling in the range of 1 200 to 2900C and said distillate containing aliphatic olefins, to produce a reaction product having a boiling range which is higher than that of said hydrocarbons as the main component of said distillate and which is not lower than 2600C.

2. A method according to claim 1 wherein said distillate from the thermal-cracked oil further contains aromatic hydrocarbons and at least 10 weight percent of aliphatic olefins.

3. A method according to claim 1 wherein said hydrocarbon feed is a distillate from a thermalcracked oil obtained in a thermal cracking process for thermally cracking a petrolic heavy residual oil at a temperature not lower than 4000C and not exceeding 7000 C, said distillate consisting mainly of hydrocarbons boiling in the range of 1200 to 2900C and said distillate containing aliphatic olefins.

4. A method according to claim 1 wherein said hydrocarbon feed is a mixture of: (I) 20-95 weight percent of a thermal-cracked oil distillate obtained from a thermal cracking process for thermally cracking a petrolic heavy residual oil at a temperature not lower than 4000C and not exceeding 7000 C, said distillate consisting mainly of hydrocarbons boiling in the range of 1200 to 2900C and said distillate containing aliphatic olefins; and (II) (A) 80-5 weight percent of at least one distillate boiling in the range of 1500 to 28O0C and selected from the following (a) through (c): (a) a thermal-cracked by-product oil distillate obtained by thermal cracking of a petrolic light oil at a cracking temperature in the range of 7500 to 8500 C; (b) a reformate distillate obtained by catalytic reforming of a petrolic light oil boiling in the range of 500 to 2500C; and (c) an aromatic hydrocarbon distiilate consisting mainly of aromatic hydrocarbons and obtained by separation from said thermal-cracked by-product oil distillate (a) and/or said reformate distillate (b); or (B) 80-5 weight percent aromatic hydrocarbons having a boiling range lower than 1 500 C.

5. A method according to any one of claims 1 to 4 wherein said thermal cracking process is a coking process.

6. A method according to claim 5 wherein said coking process is a delayed coking process.

7. A method according to any one of claims 1 to 6 wherein said acid catalyst is selected from aluminum chloride, boron fluoride, their complex, hydrogen fluoride and silica-alumina.

8. A method as claimed in claim 1, substantially as hereinbefore described with particular reference to the Examples.

9. A method as claimed in claim 1, substantially as illustrated in any one of the Examples.

10. The product obtained by the process claimed in any one of the preceding claims.

1 A product as claimed iri claim 10 which has been hydrogenated.