US2226261A - Cracking of oils - Google Patents

Description

: 25 range.

Patented Dec. 24, 1940 UNITED STATES PATENT OFFICE 2,226,261 a CRACKING or OILS Joseph Rivkin, Pittsburgh, Pa., assignor to The Neville Company, Pittsburgh, Pa., a corporation of Pennsylvania Application June 22, 1939, .Serial No. 280,574 3 Claims. (01 196-55) This invention relates to the treatment of high 10 treatment of light oil and light oil fractions produced in the high temperature by-product coking of coal, and may therefore be described with particular reference thereto. Two exemplary classes of such oils are the material known in the trade is as heavy oil and the high boiling oils contained in the material called pure still residues.

Inthe high temperature by-product coking of coal the gases are commonly scrubbed with a wash oil to absorb and form asolution of the light '20 oils which is then distilled tgmecover the light oils, chiefly benzoi, toluolf' xylol and solvent naphtha. This light oil mixture is then fractionated to obtain the individual constituents as somewhat impure cuts of rather narrow boiling The crude fractions, or cuts, are then usually" washed with a small amount of strong sulfuric acid, andafter separation from the acid stratum washed with alkali, to neutralize acid, following which they are distilled to produce 30 commercially pure solvents, leaving in the stills a residue comprising a mixture of resinous polymers, high boiling oils and a greater or lesser amount of the solvent. The usual practice is to combine the residues from the various fractions 35 and then to subject the mixture to distillation to strip out rather completely the content of solvent oil, such as benzol and the like. The residue from this operation forms what is known in the trade as pure still residue, although the 40 term may be applied also to the residue left after fractionation of any of the various light oil cuts. It comprises chiefly polymers of unsaturated compounds, largely of resinous nature, and other reacted bodiesappearing as high boiling oils. 45 The oils contained in pure still residue may be separated from its resin content in various ways but most suitably by the treatment described in Patent No: 2,149,577, granted March '7, 1939, to William H. Carmody. In accordance therewith 60 the still residue is heated suiliciently to render it thin and free flowing, say above about 250 C., desirably at about 275 to 280 C. It is then blown with live steam while maintaining it at such an elevated temperature, whereby the oily as content of the still residue is carried over by and condensed with the steam. The condensate'is then treated by heating it to about 90 to 95 C.

and then permitting it tostand. In this manner the water and oils stratify rapidly so that the latter may be separated easily from the former. 5

The oil stratum is then heated to a temperature.

between 100 to 150 0. whereby the water is distilled off, leaving the oils dehydrated sufllciently for most purposes.

The crude solvent naphtha fraction of light oil carries substantial amounts of polymerizable constituents, largely coumarone and indene with, in some instances, a greater or lesser amount oi dicyclopentadiene. This fraction is ordinarily subjected to a polymerization process whose object is to convert the unsaturated and polymerizable constituents into resin, the so-called coumarone or coumarone-indene resin. These polymerization processes generally produce, in addition to the desired hard resin, a greater or 2 lesser proportion of lower polymers, chiefly the} dimers and trimers of coumarone and the other polymerizable constituents, which are oily and. of relatively. high boiling point. After such a polymerization process the solvent naphtha is removed by distillation leaving the polymerized material in the still. The polymers are then steam distilled to remove these oily materials from'the hard resin. The oily material recovered in this manner is known in the trade asheavy oil.

Pure still residues have been generally considered to be waste materials, or by-products, of I little or no value. It has been difficult to resolve them into their individual constituents, or at least to do so economically, and they have been of such low market value that for convenience and easy disposition they have commonly been added to coke oven tar or burned'as fuel, for lack of more profitable ways of disposing of them. Although various modes of treating them 40 have been proposed, the art has needed other cheap and simple processes of treating these and similar materials for the purpose of converting them into products of improved value; v Similarly, heavy oil is of relatively little value,

and its accumulation as a result of the processes described presents a disposal problem.

The major object of this invention is to provide a process of treating high boiling oils, such as those referred to above and others, for producing lower boiling products of greater value, particularly light oils, which is easily practiced, effective for its intended purpose, may be performed with standard apparatus, and is inexpensive.

, The invention is predicated upon my discovery that heavy oil, the oils contained in pure still residues, and other high boiling oils, 1. e., oils boiling over about 200 C., can be cracked readily and easily by heating them with activated clay. Thereby such materials are cracked easily and smoothly with production of lower boiling products of greater value. Light oils, i. e., oils boiling below about 200 C., may be produced easily in this manner, and they are, of course, of greater value than heavy oil, oil contained in pure still residue, and the. like. Some oils when treated in this manner give chiefly cracked products which are saturated, or substantially so. Others, however, undergo reactions in cracking with production, not only of saturated lower boiling products, but also of unsaturated polymerizable materials which under the influence of heat and the activated clay become polymerized with production of resins of commercial utility.

A feature of the invention of major importance is that certain difiiculties and disadvantages encountered heretofore in attempts to crack these and related materials are substantially eliminated. For example, in such cracking operations there are generally formed amounts of darkcolored carbonaceous or tarry products which may be, and frequently are, difiicultly removable from cracking residues in the still whose commercial value is reduced by the consequent discoloration. I have discovered that in the practice of this invention such materials are taken up, by absorption or adsorption, by the clay concurrently with their formation. Consequently when the cracking residues are filtered to separate them from the clay the discoloring matter is simultaneously removed to give a clear filtrate free from such materials.

Another important advantage is that the troubles which result from cracking with metallic chlorides. such as aluminum chloride, are eliminated. Thus, the present invention eliminates the difficulties due to corrosion which arises in the use of aluminum chloride, and eliminates the difficulties encountered in satisfactorily and economically separating aluminum chloride from the medium in which it is contained.

The temperature at which the mixture of high boiling oil and activated clay is heated will depend in part upon the particular oil or oily material which is being cracked, and also upon the particular lower boiling products desired. Accordingly. no specific temperature or range of temperatures can be given applicable to all of the materials which may be treated in accordance with the invention. It is necessary, however, only to heat the mixture of oil and clay, preferably under vigorous mechanical agitation, to

a temperature at which the desired cracking will be effected. the temperature being kept low enough to avoid undesired decomposition. Similarly, exact limits for the proportion of clay to oils can not be stated because this will depend, at least in part, upon the character of the activated clay and other factors. Both of these factors can be determined readily for any given case,

as will be understood by those skilled in the art. but they are exemplified by the following actual tests of the invention.

The accompanying drawing represents in the form of a fiow diagram the course of the materials involved in a typical embodiment of the process of the present invention.

Treatment of heavy oil In this test there was used #2 heavy oil sold by The Neville Company of Pittsburgh, Pennsylvania. This oil possessed a boiling range as follows:

500 cc. of this heavy oil were placed in a round bottom flask and heated to 110 0., when there were added '75 grams oi activated clay of the grade sold as Superflltrol," which resulted in quick dehydration of the clay. A fractionating column and condenser were' then mounted on the flask and heating was continued. Cracked distillate began to come over at a vapor temperature of 135 C., and this continued to a vapor temperature of 198 C.. when heating was stopped. Concurrently with distillation of cracked oils there was polymerization of unsaturated cracking products. flask was diluted with benzol and filtered, the filtration proceeding easily and quickly. The filtrate was distilled for recovery of residual products. The yields were as follows:

250 cc. of cracked distillate boiling under 200 C.

52 cc. of distillate boiling above 200 0., mainly heavy oil 182 grams of a brown resin melting at 90 C.

The cracked distillate boiling under 200 C. contained an appreciable, though not very great, amount of unsaturated constituents which yielded a clear amber-colored and brittle resin on treatment with concentrated sulfuric acid. This trac tion also exhibited the following properties:

Sp. gravity at 15.5/l5.5 C.0.942

Treatment of oils from pure still residue In this test there was used the dried oily material steam distilled from pure still residue. This oil had the following boiling range:

Initial 205 5% 210 243 260 2'74 287 299 308 '70 310 320 341 357 99 365 (decomposition) The residue in the 500 cc. of dried oil were placed in a round bottom flask and heated, and '15 grams of "Superfiltrol clay were added to the oil at 100 to 130 0., whereby most of the water contained in the clay was promptly driven oil. A fractionating column and condenser were then mounted on the flask and heating was continuedto eflect cracking and fractional distillation. Fractions were collected as follows: I s

- I lquid out i tillate cuts Percent (vapor temyield perature) Cut A-4 included 5 per cent of solid naphthalene which was collected separately.

The residue left in the flask was a black, heavy viscous fluid at room temperature. It was diluted with benzol and filtered to separate it from the clay and absorbed impurities. The clear filtrate was distilled to remove the benzol, and it was then blown with hydrogen at a liquid temperature of 290? to 315 C., collecting as a distillate a somewhat viscous yellow oil amounting to 12 per cent by volume of the original dried steam distillate. This left as a'residue a dark brown resin of about 40 C. melting point and amounting to 15 per cent by weight of the original dried steam distillate.

Cut A-4 was now subjectedto cracking in ac- I cordance with the invention in the manner described above, using 15 grams of fresh activated clay per 100 cc. of the oil. At a vapor temperature of 88 to 199 C. .(liquid temperature of 148 to 283 C.) there distilled over a liquid (B-l) comprising 35 per cent by volume of the cut, which represented 13 per cent by volume of the original dried oil distillate. The residue remainingin the flask was a'deep yellow oil which fil- The invention is not restricted to the treatment of materials as described hereinabove, but is applicable equally to the cracking of other high boiling oils, and also to the cracking of high boiling oils of different nature than those speciflcally described, for instance to the treatment of oils of essentially aliphatic nature. As exemplifying the treatment of such other materials by the process of .the invention, reference may be made to the following test.

Treatment of petroleum oil 500 cc. of a petroleum medicinal white oil having an initial boiling point of 360 C. were placed in a flask,.heated and mixed with 75 grams or superfiltrol activated clay at 110 to 140 C. After the clay had been substantially dehydrated a iractionating column and condenser were mounted on the flask and heating continued with cracking and distillation of the products. The following distillates were collected: i 9

Boiling'ranfi Percent Cut oicraokodd tillatecuts (by vol.)

"0. Percent 1 78-1!) 21 a amp-ass so The cracking residue'was filtered easily without dilution to separate it from the clay and its adsorbed matter. The filtrate was an oil of about the same viscosityas the original oil, and

it appeared to be uncracked residue or the initial white oil. Thistest illustrates the case where no polymerizable products are produced.

It will be seen that the invention thus provides for simple, ready and economical cracking oi high boiling oils, and particularly of waste materials, to produce more valuable lower boiling oils and, depending upon the nature of the starting materials, resins of commercial utility.

Particularly, it produces desirable yields of light oils. An especially important featureis that in a single operating step there are accomplished two important results, viz., cracking of high boiling oil into lower boiling oils with concurrent polymerization of polymerizable bodies that may form during cracking, and, simultaneously, eflective removal of discoloring. matter formed during the treatment. The combining of the latter resuit with the former is important because thereby materials free from discoloring bodies are obtained simply by filtration. This is an important advance in the artbecause the difiiculties and expense encountered heretofore in eliminating such carbonaceous discoloring matter are avoided.

According to the provisions of the patent statutes, I have explained the principle and method of practicing my invention and have described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. I

I claim: i

1. That method of converting into products of improved value oils boiling over about 200 C. and derived from the purification and treatment of light oils produced in by-product coking of coal, which comprises heating and agitating said oil and activated clay at a temperature produc- "tive of cracking, and thereby in a singleoperating step producing lower boiling oils of greater value, with concurrent polymerization to resin of unsaturated polymerizable products of cracking, and adsorbing dark-colored carbonaceous and tar-like cracking residues on said clay, distilling on said lower boiling oils, adding resin solvent to the residue and filtering the solution to separate it from said clay and produce filtrate substantially free from said dark-colored residues. n distilling volatile matter from saidflltrate to recover said resin polymer.

2. A process according to claim 1, said 011 being heavy. oil.

3. A process according to claimv 1, said 011 being that contained in pure still residue.

, JOSEPH RIVKIN.

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