This invention pertains to the cracking and refining of petroleum oils, and may be characterized typically as providing an improved system for initially subjecting an acceptable charging inventory to in depth cracking to provide a high share of lighter than gasoline however potential gasoline forming fractions and compounds, after which subjecting these cracked merchandise to polymerization underneath conditions productive of an abnormally high yield of recoverable gasoline fractions.
In accordance with the invention, the charging stock first is subjected to cracking beneath high temperatures, and ideally beneath comparatively low pressures, for the aim of inflicting a excessive diploma of dissociation or cracking of heavier than gasoline fractions, and the manufacturing of lighter than gasoline compounds able to polymerization to kind gasoline fractions of nondetonating qualities. Using the current system 2( it is feasible, because of the effectiveness of the polymerizing stage, to initially subject the hydrocarbons to extra intensive cracking than would usually be desirable or economical as a result of extreme mounted gas losses. 2 After the hydrocarbons have been subjected to cracking beneath such circumstances, the cracked vapors are polymerized by contact with catalytic material and below excessive strain that can produce an abnormally high degree of polymerization of the vapors within the presence of the catalyst.
Following cracking, and with or with out preliminary fractionation or polymerization, the vapors are mechanically compressed to a excessive stress and preferably are subjected to polymerization by contacting them with adsorptive materials, as by passing the vapors by way of a body of adsorptive clay. Being maintained beneath high pressure while subjected to the action of the clay, the nonvolatile constituents of the vapors bear a high diploma of polymerization, with resultant and proportionate formation of gasoline fractions.
After polymerization, the vapors may be further handled or fractionated by any appropriate technique to condense and individually remove fractions heavier than gasoline, and to lastly condense the product gasoline.
The invention will likely be understood to greatest advantage from the following detailed description of a typical system embodying the invention and illustrated diagrammatically and in movement sheet form within the accompanying drawing.
The charging stock introduced to the system by means of line 10 might include any appropriate petroleum hydrocarbon or fraction thereof, able to undergoing cracking within the still I I to a level such that the desired relatively excessive yields of polymerizable and potential aromatic and other excessive octane ranking compounds, will likely be formed.
Thus the charging stock could include suitable crude oil or fractions comparable to fuel oil, fuel oil or kerosene distillate. Additionally the invention contemplates cracking the hydrocarbons in still 1 in either liquid or vapor phases, although normally will probably be preferred to keep up cracking temperatures and pressures on a given hydrocarbon undergoing cracking, such that the cracking reactions will occur not less than largely in vapor part.
In flowing from line 10 by means of the conventionally illustrated cracking still I , which could also be of any suitable sort and design, the charging stock undergoes cracking at temperatures which will vary from 900′ to 1300′ F., or above, relying upon the nature and composition of the charging 0 stock, below nevertheless relatively low pressures, for example from considerably atmospheric as much as around 75 lbs. per sq. in. The place in order to acquire the specified diploma of cracking in stillI i it may be essential to crack the hydrocarbons at significantly greater pressures, any desired stress may be maintained on the oil undergoing cracking, as by a valve 12 in the outlet line thirteen, and the pressure then decreased to below say 75 lbs. per sq. in., beyond the valve.
SThe cracked hydrocarbons are discharged by way of line thirteen into an enlarged separating chamber or reaction zone 14 wherein any carbon and unvaporized residue are separated from the vapors and faraway from the system by means of 35 line 15. The cracked vapors leaving chamber 14 through line IS then are subjected to compression and subsequent polymerization, both with or without first being additional handled upfront of the point of compression. As illustrative, the forty vapors may pass instantly from line sixteen by way of line eleven to a compressor or collection of compressors of a type adapted to handle high temperature vapors, and conventionally illustrated at 18, or the vapors could first be discharged by line forty five 19 for preliminary remedy, polymerization or fractionation by any suitable means, typified by column 20. Merely as illustrative, this column could comprise a physique of adsorptive material 21 through which the vapors bear preliminary 50 polymerization in flowing upwardly to the outlet 22 connecting with line 17. Alternatively, column 20 might consist of an odd fractionating column inside which the heavier ends are condensed out of the vapors. The liquid polymers 55 or condensate, because the case may be, are removed from the base of column 20 by means of line 23 to 1 recirculated by line 24 for cracking in st I , or discharged to storage by means of line 2 Where column 20 or different similar apparatus used, it’s most popular to again topic the liqui polymers or condensate to cracking and to retur the cracked merchandise to chamber 14 so as thE from a given charging inventory, a most yield c lighter cracked hydrocarbons will be produce for conversion within the excessive strain stage of th system.
卤he relatively low pressure vapors flowin by way of line 17 to the compressor, are compressei by the latter to a comparatively excessive pressure, whic ordinarily will likely be not less than 200 pounds per sq. in increased than the vapor pressure on the inlet sid, of the compressor, preferably to a pressurn of around four hundred lbs. to 600 Ibs. per sq. in. gauge Relying upon the traits of thg cracked vapors and the type of catalyst employed within the polymerizing chamber, pressures in excess of those named may be used in ordei to obtain maximum levels of polymerization The compressed vapors are discharged from compressor 18 through line 26 to a polymerizing zone shown usually as a vertically extending column 27. Ideally, polymerization is not less than partially induced by contacting the vapors with a suitable adsorptive material corresponding to fuller’s earth, bauxite, Murock, or Dying Valley clays, employed in enough amount to topic the vapors to intimate and prolonged contact therewith. Accordingly, column 27 is shown to include a physique 28 of such adsorptive materials extending vertically above the point of entry of the vapors a substantial distance so that the vapors have a chronic path of movement by way of the clay. A number of of such columns after all may be employed, relying upon the specified time of contact and length of vapor travel via the clay. The polymerizing chamber may comprise in place of or along with the adsorptive clay, different catalytic brokers capable of promoting polymerization of the vapors. For instance the clay physique may include or be impregnated with any of the metals, metallic compounds, and particularly metallic salts, recognized to have the property of catalyzing the reactions of polymerization.
In thus being subjected to polymerization une der excessive strain, a large percentage of the in poor health larger boiling and usually uncondensible vapor 5. fractions are transformed to condensible hydrois carbons inside the gasoline vary. At the identical id time, gum-forming compounds are transformed to n heavy liquid polymers which drain to the botit tom of the column 27, from which they could also be )f faraway from the system by way of line 29 or pink circulated by means of line 30 for recracking in still e 10 I . Polymerized vapors leaving the column via line 31 may be subjected to any desired g additional treatment and technique of condensation 1 or fractionation to supply the gasoline product.
S Merely as illustrative, the vapors are shown to .15 be subjected to preliminary fractionation in column e 32, from the bottom of which heavy condensed fractions, for instance within the gasoline oil range, might . be removed to storage by means of strains 33 and 34, Sor recirculated to the cracking nonetheless by means of line 35. Leaving fractionating column 32, the vapors circulate through line 36 to the fractionating column 37 wherein heavier than gasoline fractions, akin to hydrocarbons within the kerosene distillate vary, are condensed and faraway from the system via lines 38 and 39, or returned to the cracking still by means of line forty. The vapors in fractionating column 32 could also be subjected to reflux condensation by condensate delivered to the top of the column from the bottom of fractionating column 37 by way of line 41. Cracked gasoline vapors leaving column 37 by means of line 42 go by ultimate condenser 43 and the condensed gasoline flows by means of line forty four to receiver 45. Fastened and uncondensible gases go away the system via the valved line forty six.
