US2090766A - Process for treating mineral oils - Google Patents

Description

Aug. 24, 1937.

. a @N QN on Pl m- Aug. 24, 1937. E. w. REMBERT 2,090,766

PROCESS FOR TREATING MINERAL OILS Filed July 22, 1932 2 Sheets-Sheet 2 Patented Aug. 24, 1937 UNITEDv STATES PATENT OFFICE PROCESS FOR TREATING MINERAL OILS Ernest Wayne Rembert, Plainfield, N. J., assig'nor, by mesne assignments, of three-fourths to Tide Water Associated Oil Company, New York, N. Y., a corporation of Delaware Application July 22, 1932, Serial No.- 623,978 3 Claims. (01. 196+s1 oils and/or liquids containing compounds of the.

same or different chemical series from those treated, and more especially to produce lower boiling oils and liquids such as motor fuel products, gasoline, and the like, and also higher boiling oils. A particular application of the invention is in the production of motor fuel material having excellent anti-knock properties. This invention comprises improved processand apparatus for efiecting such operations.

This invention constitutes improvements in process and apparatus over an invention described in my Patent No. 1,892,534, dated December 27, 1932'. The specific improvements described herein insure continuous and improved operation when the hydrocarbon material that is intermixed with hot combustion gases is in either a liquid or a fog form. The process is par- .ticularly adapted to the crackingof materials containing residuals, that is to say, materials which can not ordinarily be completely vaporized without a substantial amount of cracking taking place, such as crudes or crude oils from which some or all of the lower boiling constituents have been removed by distillation.

In the invention described in my Patent No. 1,892,534, dated December 27, 1932, I disclosed a method in which liquid hydrocarbons are sprayed into hot and substantially untempered products of complete combustion of air and hydrocarbon fuel, and are mixed instantaneously and by this step are vaporized and superheated to such a point that substantial decomposition or decomposition and recomposition take place, after which the products of the reaction are quickly cooled by very intimate admixture with cold oil, which in the preferred form of the invention is the raw material to be processed. Difficulties may be encountered in the operation of this process when charging materials which are difficult to vaporize or materials which are difficult to atomize into such a fine state of subdivision that subsequent vaporization is substantially instantaneous.

This invention relates to an improved method of obtaining the vaporization of such hydrocarbon materials beforethese are superheated to the cracking temperature.

The main object of this invention is to provide a method whereby liquid hydrocarbon materials or fogs of liquid material held in vapors can be readily converted to altered or low boiling hydrocarbons with a minimum formation of fixed gas and free carbon.

A further object of this invention is to insure complete vaporization of such liquids and fogs before these materials are superheated to a temperature at which the cracking reaction will take place rapidly.

A further object of this invention is to provide a more positive method for the controlling of the cracking reaction so that the optimum amount of cracking takes place and substantially no overcracking occurs.

An additional object of this invention is to provide a method for cracking heavyhydrocarbons in such a manner that substantially no coke or heavy tar is formed and the continuity of the operation is not interrupted.

A further object of this invention is to present a method for converting heavy hydrocarbons by which the maximum yields of low boiling materials suitable for motor fuels can be obtained.

A further object is to produce from heavy hydrocarbons a motor fuel material having marked anti-knock characteristics.

In one form of the process described in my Patent 1,892,534, the material to be cracked is withdrawn from an accumulator zone and, after passing through a pump, is introduced through spray nozzles into a reaction chamber where the liquid is instantaneously vaporized and superheated to the cracking reaction temperature. I have found that a very fine subdivision of the liquid particles is necessary when these particles are mixed with the hot gas. This is essential in order that the vaporization of the liquid by, and

the mixing of the vapors so formed with, the

heating gas be very rapid and uniformity of temperature be obtained substantially instantaneously. If relatively large droplets are fed into the hot gas, the material vaporized from the surface of the droplet is immediately raised to a temperature which is considerably higher practically instantaneous, owing to the extremely large ratio of surface area to volume. Then the temperature equilibrium desired is obtained so quickly that no overcracking occurs. This can be accomplished with atomizing nozzles that are available at the present time, but with some oils it is exceedingly difilcult to operate for a great. length of time and continue to atomize the liquid material into particles sufliciently small to obtain the desired results. Corrosion and erosion are likely to occur eventually and tend to destroy the symmetry of the orifice, with the result that the total liquid may not be formed into sufficiently small droplets.

The novelty of this invention lies in the method of insiu'ing substantially complete vaporization with relatively little superheating before the materials to be cracked are raised to the cracking temperature. To accomplish this, I introduce the hydrocarbon material as an atomized spray or as a fog into a vaporizing chamber, where these materials are mixed with the hot and preferably non-oxidizing gas, the volume of which is independently controlled. The gases and the atomized liquid material are quickly and thoroughly mixed and reach a temperature of equilibrium which is such that the material to be cracked is held in vapor form in admixture with the gas at a temperature at which little or substantially no cracking takes place in the short period of time during which the mixture remains at this temperature. This mixture of vapor and gas then passes to a reaction chamber in whichadditional heating gas, independently controlled as to volume, is introduced into this material in such a way that instantaneous mixing takes place. This gas consists of the products of combustion of fuel and air and preferably impinges at an abrupt angle on the stream of vaporized hydrocarbon and gas emitted from the vaporizing chamber. The amount and temperature of the gas is determined by the temperature at which the cracking reaction is to proceed. After these materials, that is the heating gas and the hydrocarbon materials, have been maintained at the cracking temperature for a definite reaction time, they are quickly chilled by a relatively cool oil which is sprayed in fine subdivision against the stream of reaction products. In this way the reaction products are quickly cooled to a temperature at which cracking reactions cease or are substantially arrested, after which they may be scrubbed by a hot liquid oil for the removal of any lampblack which may have been formed during the course of the cracking reaction, owing to'the low hydrogen content of the oil cracked or to irregularities in the operation. The mixture of vapor and liquid may then pass to a separator so that such wetted lampblack and any fine droplets of oil are separated out, after which all the material may pass to an accumulator where the liquid material collects for re-circulation. The vapors and gas proceed directly to the bubble plates of a fractionating column.

A preferred embodiment of apparatus and mode of carrying out the process are illustrated in the accompanying, somewhat schematic drawings, in which:

Fig. 1 is a view, partly in vertical section and partly in elevation, illustrating a system of apparatus embodying the invention, various parts of the system being shown schematically; and

Fig. 2 is a similar view illustrating a modification. Numerous other forms and embodi construction that a short flame is produced.

ments of the invention will suggest themselves to those skilled in the art.

Hot liquid oil, which has collected in accumulator zone I, is withdrawn by hot pump 2 and passes through strainer 3, where any material such as lampblack or carbon particles or iron scale is caught. The oil then passes under pressure through feed line 4 to valved pipe 5 which connects with one or more spray nozzles 8. This nozzle may be of any suitable design which will insure substantially complete atomization of the oil passing through it. Such atomization may be mechanical, that is, the result of a relatively high pressure drop taking place as the oil passes through the nozzle. It is also possible to increase the effectiveness of the atomization by introducing steam through valved line I, to pass with the oil through the nozzle.

The oil particles are mixed with heating gas in mixing chamber 8. This heating gas is produced by the combustion of fuel and air in combustion chamber 9. In the preferred form of apparatus, several burners l are used, of such It is desirable that there be a high degree of turbulence in the combustion chamber so that the gases as they pass through the converging and diverging throat II will be of constant composition and temperature. The temperature and amount of the gas, in relation to the amount, composition and temperature of the material to be heated and vaporized, are such that, after complete mixing of the atomized oil and heating gas has taken place, the temperature of the mixture will be on the order of 750850 F., this temperature to be determined in accordance with the readiness with which the material cracks and the ease with which it can be vaporized.

Thorough and rapid mixing takes place in the enlarged mixing chamber 8, and a uniform temperature is obtained of such a. degree that substantially all the oil introduced through the nozzle 6 is vaporized. The mixture of gas and vapor then passes into the reaction tube l2, at the beginning of which sufllcient additional heating gas is mixed with these materials to raise the temperature of the mixture above 1000 F. The temperature to be attained in this stage of the process is on the order of 1050-1250 F., though much higher temperatures can be employed if the reaction time is made short enough. Very brief reaction times are employed in this process, ranging upward from a small fraction. of a second to a second or more. The reaction time is controlled for a reaction chamber of given volume by the rate at which the mixture is passed through it.

In the preferred form of the apparatus, the additional heating gas independently controlled is provided by one or more burners i3 which deliver their flames into an annular combustion chamber H surrounding the entrance portion of the reaction tube. This chamber is of suflicient size to insure complete combustion before the hot produets of combustion can encounter the mixture of vapor and heating gas that enters the reaction zone from the mixing chamber 8. A ring I of refractory checker-brick, or other refractory walling provided with numerous passages through it, surrounds the second mixing region in the entrance end of the reaction tube. Such a division between the reaction chamber and the second hot gas chamber causes the heating gas to enter as numerous impulsive streams or jets into the stream of mixture flowing through the tube,

the angle of intersection being abrupt so that great turbulence and quick and uniform mixing are obtained.

At the end of the reaction tube, and after the augmented mixture has been kept at the reaction temperature for a definite time, cool oil in a state of fine division is introduced through sprays IS in a quencher H, in order to cool the reaction products instantaneously to a temperature at which substantially no further cracking takes place. This temperature is on the order of about 750 F., or as much lower as is necessary to insure the practical arrest of reactions.

The quenching material, or the unvaporized part of it, and the gases and vapors, then pass through a scrubber l8, where hot oil withdrawn from the accumulator and circulated through valved line I9 is sprayed in through nozzles 20. This serves to wet any lampblack particles formed in the reaction products. Then, the liquids and vapors pass through a separator 2|, where fog particles and wetted lampblack are removed from the gases and vapors, so that clean vapor and gas are delivered to the fractionating column 22. If the accumulator I is located at the base of the column, the liquid, vapor and gas may all be passed to the accumulator through a large pipe 23. The liquid is collected in this zone for recycling, and a portion may be withdrawn through line 24.

The gas and light vapors pass from the top of the fractionating column through a line 25 to a condenser and cooler 29, from which the liquid and gas pass to a gas separator 26, from which the gas is taken off at 21, while the condensed light distillate passes through pipe 28 and is withdrawn. Refiuxing liquid is pumped-into the upper portion of the tower through a line 30, and reflux condensate, such as gas oil, may be taken oil from a lower plate through a line 3|. Water resulting from combustion is drawn oil from the gas separator at 28.

The combustion chambers or heating gas chests, the mixing chamber and the reaction chamber are preferably constructed in one unit of refractory and heat-insulating materials 32 enclosed in a metal shell 33. The throat or orifice ll. opens through a bridge wall between the combustion chamber 9 and the mixing chamber 8, and the feed nozzle 6 is preferably located in or adjacent to this orifice, and delivers the material to be mixed with and vaporized by the hot gas in uniform distribution and in intimate contact therewith. The burners are supplied with fuel gas and air under pressure from blowers 34, 35 through valved lines 36, 3! connecting with piping 38 from which the combustible mixture is supplied to the burners. By means of the valves represented in the lines 36 and 31 and in the branches 38 supplying the combustible mixture to the two sets of burners l and I3, the volumes of the hot combustion gases mixed with the hydrocarbons in the two stages of the process are controlled. The quencher I1 is applied directly to the discharge end of the reaction chamber.

Modifications of this apparatus and of the manner of performing the process are, of course, permissible.

As shown in Fig. 2 heating gas may be withdrawn from the combustion chamber 9 through a duct 39, having a regulating damper 40, to the chamber [4, which then becomes a heating gas chest without burners. Similarly, heating gas may be produced by combustion or may be heated,

elsewhere than in the unit and may be supplied to the two mixing regions.

While the temperature to which the hydrocarbons, are subjected at the first mixing, heating and vaporizing step is within the lower range of cracking temperatures, the rate at which reactions proceed at these temperatures is relatively low, and the liquid hydrocarbons in their state of fine dispersion are so instantaneously vaporized and remain in the first mixing zone for so short a time that any amount of cracking at the vaporizing temperature is inconsequential. As soon as the hydrocarbons are vaporized and thoroughly mixed with the first supply of heating gas, they are quickly mixed with the second supply, by which the temperature of the mixture is elevated to the range above 1000 F. at which conversion to produce substantial amounts of aromatic and other bodies of anti-detonating qualities is obtained.

In the drawings, the feed of a liquid spray direct to the primary mixing chamber has been illustrated, but it is to be understood that a fog or mist feed as disclosed in my application Serial No. 623,979, filed July 22, 1932, is equally applicable, in which case the material in the liquid phase is carried in a fine state of dispersion in gas or in vapor, more especially hydrocarbon vapor also to be cracked.

I claim:

1. A continuous process of converting hydrocarbons in the vapor phase, which comprises continuously feeding and introducing all of the hydrocarbon material which is to be converted to a vaporizing zone, in such form that a considerable part at least of said material is in the liquid phase and that part is finely dispersed, continuously producing hot, non-oxidizing combustion gases and introducing them into said vaporizing zone, the volume of said gases being independently controlled, intimately and rapidly mixing the hydrocarbon material with said gases to effect complete and sudden vaporization of the liquid phase material, passing the mixture through the vaporizing zone so quickly that cracking of the hydrocarbons is substantially precluded notwithstanding temperatures of the mixture of the order of 750-B50 F., immediately passing the entirety of the hydrocarbon vapors and gases, without withdrawal of any liquid from the vaporizing zone, to a reaction zone to which no more liquid is admitted and from which none is withdrawn, abruptly raising the temperature of the vaporized hydrocarbons to above 1000 F. by admixture of additional hot combustion gases, which additional gas is also independently controlled as to volume and is introduced substantially at one region, where the vapors and gases from the vaporizing zone enter the reaction zone, passing the augmented mixture through the reaction zone at a rate which gives a brief reaction time, and suddenly quenching the issuing mixture by intimate contact with cooling liquid.

2. A continuous process of converting hydrocarbons in the vapor phase, which comprises continuously feeding and introducing all of the hydrocarbon material which is to be converted to a vaporizing zone, in such form that a considerable part at least of said material is in the liquid phase and that part is finely dispersed, continuously producing hot, non-oxidizing combustion gases and introducing them into said vaporizing zone, the volume of said gases being independently controlled, intimately and rapidly mixing the hydrocarbon material with said gases to effect complete and sudden vaporization oi the liquid phase material, passing the mixture through the vaporizing zone so quickly that cracking of the hydrocarbons is substantially precluded notwithstanding temperatures of the mixture of the order of 750-850 1"., immediately passing the entirety of the hydrocarbon vapors and gases, without withdrawal oi any liquid, to a reaction zone to which no more liquid is admitted and from which none is withdrawn, abruptlyralsing the temperature of the vaporized hydrocarbons to above 1000" F. by admixture of additional hot combustion gases, which additional gas is also independently controlled as to volume and is introduced substantially at one region, being there injected with high turbulence eifect into the gas and vapor stream passing from the vaporizing zone to the reaction zone, passing the augmented mixture through the reaction zone at a rate which gives a brief reaction time, and suddenly quenching the issuing mixture by intimate contact with cooling liquid.

3. A continuous process oi! converting hydrocarbons in the vapor phase, which comprises continuously feeding and introducing all of the hydrocarbon material which is to be converted to a vaporizing zone, in such form that a considerable part at least of said material is in the liquid phase and that part is finely dispersed, continuously producing hot, non-oxidizing combustion gases and introducing them into said vaporizing zone, the volume of said gases being independently controlled, intimately and rapidly mixing the hydrocarbon material with said gases to effect complete and sudden vaporization of the liquid phase material, passing the miximre through the vaporizing zone so quickly that cracking of the hydrocarbons is substantially precluded notwithstanding temperatures of the mixture of the order of 750"- 850 F., immediately passing the entirety of the hydrocarbon vapors and gases, without withdrawal of any liquid, to a reaction zone to which no more liquid is admitted and from which none is withdrawn, abruptly raising the temperature of the vaporized hydrocarbons to above 1000 F. by admixture of additional hot combustion gases, which additional gas is also independently controlled as to volume and is introduced substantially at one region into the gas and vapor mixture passing as a confined stream from the vaporizing zone to the reaction zone, the additional gas being jetted into said stream from several sides, passing the augmented mixture through the reaction zone at a rate which gives a brief reaction time, and suddenly quenching the issuing mixture by intimate contact with cooling liquid.

ERNEST WAYNE REMBERT.

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