US1963178A - Process for treating hydrocarbon oils - Google Patents

Description

June 19, 1934. A. F. sPlEHLE-R Er Al. 1,963,178

PROCESS FOR TREATIG HYDROCARBON OILS Filed Dec Patented June 19, 1934 PROCESS FOR TRIAILTNG HYDROCARBON Adolph F. Spehler, Beaumont, Tex., and Cary R.

Wagner, Chicago, Ill., assignors to Gyro Process Company, Detroit, Mich.,`a corporation of Michigan Application December-17,1930, serial No. 502,944 1 Claim. (o1. 19e-lso) This invention relates to improvements in the i cracking of heavy hydrocarbon oils for the purpose of producing a desired end product suitable for use as motor fuel, and the invention has par- 5 ticular reference to vapor phase cracking Asystems of the continuously operating type wherein the oils undergoing decomposition are in a state of Yvapor and maintained at high temperatures, and wherein substantially non-residual operations are obtained.

It is a primary object of the present invention to provide a continuously operating vapor phase system of conversion which admits of the employment of heavy charging stocks. In many systems of oil conversion charging stocks cannot be used successfully which have a Baume gravity below that of a medium grade gas-oil fraction, and the present invention Aprovides for the operation of the cracking process in an ecient 20 manner to admit of the employment of charging stocks such as very heavy crude oilsand even fuel oils in the production of motor fuel. In this manner the invention makes available for the production of motor fuels large quantities of hydrocarbon oils which heretofore have been placed into less useful, purposes with correspondingly minimized economic values.

Also, in earlier systems employed for the cracking of hydrocarbon oils in the vapor phase with continuous or cyclical operation, not only have such systems required in the main carefully selected charging stocks, but in -addition discharge as a residue unusable fractions in the form of fuel oil, which have a relatively low economic value as compared with the desired motor fuel product. In accordance with the present invention, a process is provided wherein the products discharged from the system comprise, first, the desired motor fuel fraction,.second, a relatively low quantity of fixed or permanent gas and, third, a dry or hardened coke deposit, regardless of the character of the charging stock used. The present 'invention thus provides a cyclical system for the conversion of oils in the vapor phase without the production ofsubstantially any fuel oil or other liquid residues of high boiling range.

For a further understanding of the invention, reference is to be had to the following description and the accompanying drawing wherein:

Fig. 1 is a diagrammatic view or now diagram of the apparatus and process comprising the present invention;

Fig. 2 is an enlarged vertical sectional view taken through the coke receiving and conversion arresting elements of the system; and

Fig. 3 is a top plan view thereof.

The features of the present invention will be more clearly appreciated by referring to the accompanying drawing, wherein is schematically set forthapparatus for use in carrying the invention into effect. The numeral 1 designates a furnace or converter setting of conventional design', which is divided internally by a bridge wall 2 for the purpose of forming combustion and tube chambers 3 and 4 respectively. The combustion chamber is equipped with suitable fuel burners 5 for the purpose of developing furnace temperatures within the chambers 3 and `4 sufciently high to heat the oil vapors traveling at high velosities through the converter tubes 6 to a conversion temperature in excess of 1000c F. Oil vapors enter the upper pass of the tube 6 by way of a vapor line 7. After passing through the tube 6, the vapors usually attain a ternv perature of approximately 1100 F. and are dis- 75 charged from the converter at this latter temperature after the desired degree of conversion has taken place.- From the converted tubes 6 the oil vapors enter a coke forming and collecting chamber 8.A Preferably there aretwo of these chambers and the cracked vapors at the high temperatures specified may enter one or the other of these chambers alternately by operation of the control valves 9, a feature which admits of the cleaning or removal of coke from one of said chambers while the other is in use.

Each of the chambers 8 is'provided with a centrally disposed ba'ile 10 which divides the chamber into compartments 8a and 8b.A I n the upper portion of the compartment ,8a there is arranged a. spray nozzle 11 which is connected with a pipe line 12 provided with a pump 13 I and, if desired, a cooler 14. The vapors entering the top of the compartment 8a directly fromv the converter and at high temperature are sprayed with oil discharged from the nozzle 11 at a temperature, for example, of 450 to 500 F. for the purpose of effecting quick reduction of the converter vapors, since the sprayed oil discharged into the compartment 8a from the line 12 is 100 l L'continuing without interruption the operation of the system while coke is being removed from the first chamber.

The cooled vapors ascend through the com partment 8a and pass by way of a pipe line 15 to a conversion arrester 16. The quantity of oil delivered into the chamber 8 by way of the nozzles 11 is only sufficient to drop the temperature of the converter vapors to not appreciably below 750 F. `Usually this temperature varies between 750 and 900 F. These vapors are then passed into the arrester 16 where they may be shock-chilled to-.a temperature below 600 F. to preclude carbon deposition.

To accomplish this, the arrester 16, contiguous to the entrance of the pipe line 15, is provided with a nozzle 17, which is connected with a pipe line 18 leading to a charging stock supply tank 19, the line 18 being provided with a pump 20. The charging stock enters the arrester 16 at a low temperature, lfor example, atmospheric, and

by coming into direct and intimate contact with the vapors discharged from the coke collecting chamber effects a sudden reduction in the temperature of said vapors to a point wherein further decomposition or coke liberation is prevented. The liquid oil which collects as;v a condensate in the bottom of the arrester 16 is withdrawn by way of the pipe line 12 and is used as a medium 'for effecting the cooling of the vapors in the chamber 8. The vapors leaving the coke collecting chamber thus pass into the arrester where they are instantly cooled to below 600 F. by spraying into the same fresh charging stock or in certain instances recycl stock.

From the arrester, thel vapors pass by way of the pipe line 21 to a fractionating tower 22, and the recycle stock collected in the bottom of this fractionating tower as a condensate comprises a 100% overhead gas-oil. The recycle stock or condensate drawn from the bottom of the fractionating tower 22 may be led to a tank 23 and'is then'forced by way of a pipe line 24 to a pump 25 through a bank of tubes 26 arranged in the vaporizing sections 27 of the furnace setting 1. The furnace gases discharged from the chamber 4 are passed by way of a duct 28 into the vaporizing section 27, and these gases, either by themselves-or with the aid of auxiliary combustion of the'section 27, are employed for the purpose of heating the oil passing. through the tubes 26 to a temperature sufficiently high to effect vaporization ofthisgg'as-oil or recycle fraction.` The oil P vapors discharged from the tubes 26 at a vaporizing but non-cracking temperature pass to an evaporator 29 wherein approximately 95% of the recycle stock is transmitted to the pipe line 7 as vapor. The small amount of condensate which forms inthe evaporator is continuously removed from the latter vand is discharged into the pipe line 12 where it is commingled with the condensate from the arrester 16 and is used as a temperature reducing medium in the chamber 8.

The vapors which pass overhead from the fractionating tower 22 may be condensed in the cooler 30 and collected in the storage tank V31 as a motor fuel, suitable means being provided for removing from the tank 31 the fixed gas which is formed in the conversion zone of the system.

The advantages of the above method of operation reside largely in permitting oil refineries to utilize their heavy/crude oils and even fuel oils as charging stock in the production of motor fuels having the boiling range of gasoline. In addition, the system does not produce fuel oil as a residue; coke, gas, and end point distillate being produced regardless of the charging stock used. The coke formed in the chambers 8 consists of the coke present in the charging stock plus the coke residue from the cracking operation itself. This coke consists of but a relatively small quantity of material "as compared with the total quantity of the charging stock introduced into and passed through the system. The small amount of coke developed is attributable to the rapid reduction of the' temperature of the converter vapors by the direct method of heat interchange provided. The chambers 8 are sutilciently large to permit of the accumulation after prolonged operation of a considerable quantity of the coke without in any way interfering withk and definition of the invention, as the latter has been defined in the appended claim.

What is claimed is.: A process of converting hydrocarbon oil into gasoline-like hydrocarbons, coke and gas, comprising the steps of heating hydrocarbon oil to vaporizing temperature, flashing the heated oil into vapors and unvaporized oil, withdrawing the vapors and heating them to temperatures in excess of 1000 F. .to convert the same into low boiling hydrocarbons, separately withdrawing the unvaporized oil and contacting it with the highly heated vapors in a coking zone substantially free of liquid while controlling the proportion of thev highly heated vapors and the unvaporized oil so that the heat of the vapors will convert the oil into vapors and coke, withdrawing the vapors from the coking zone, cooling the withdrawn vapors by contacting the same with the fresh oil intermittently removing the coke from the coking zone.

`ADOLPH F.- SPIEHLER.

CARY R. WAGNER.

Images