US2069358A - Hydrocarbon oil conversion - Google Patents

Description

Feb. 2, 1937. c. P. DUBBs n HYDROCARBON OIL CONVERSION Original Filed May 3l, 1930 INVENTOQ Ccrncfz E Dzzlz cfm N EY Patented Feb, 2, 1931 UNITED STATES PATENT oEFlcE I urnaocAnBoN on. coNvEasIoN Ware Application May 31, 1930, Serial No. 458,512 Renewed June 7, 1935 ZClaims.

This invention relates to the conversion of hydrocarbon oils and refers more particularly to conversion at elevated temperatures of relatively high boiling hydrocarbons into lower boiling hydrocarbons with the production of maximum yields of gas by the cracking process. The gas from the cracking process has a high caloric value ranging from approximately 1200 B. t. u.s per cubic foot to approximately 1600 B. t. u.s-'per :i cubic foot, depending upon the composition as well as the content of the entrained and absorbed hydrocarbons in the gas.

For comparison to indicate the relative caloric values of various gaseous products the following table is given:

B. t. u.s per cubic foot Cracking still gas 1250 Natural gas 1000 Carburetted water gas 550 Coke oven las 500 Producer gas 140 Blast furnace gas 100 It is quite evident that the operation of cracking processes to produce the maximum yield of gas is desirable as owing tothe high -calorii-lc value of the cracking still gas it may be used as a blending agent for the gases of lower calorific value. In some districts where producer gas and blast furnace gas and the like are produced in 3 excess of the local requirements, either continuously or during peak load periods cracking still gas may be used to enrich them and permit their use for domestic consumption, or for special industrial uses for which the gases of low calorific value are unsuitable.

The yield of gas from the cracking of hydrocarbon oils depends on the cracking conditions, such as temperature and pressure and the time during which the material is subjected to cracking conditions, as well as on the charging stock. For the so-called non-residue operation where the products of the process are a,low boiling liquid containing a motor fuel-and a non-uid or solid carbonaceous residue, the yield of gas will vary between 600 and 800 cubic feet per barrel, more or less, based on raw oil charged.

For the so-called flashing operation where the non-vaporized liquid residue from the reaction chamber is withdrawn and subjected to flashing or vaporization, and where the productsof the process include a fuel oil with little lor no coke production, the gas yield will be approximately 550 to 650 cubic feet per barrel of oil charged.

My invention is directed toward increasing the relative yield of gas based on the raw oil charged, so that the process is primarily a' gas making one, and the operation of the process is such as to ,usually produce a yield in excess of 1,000 cubic l hydrocarbon material may be used as charging 15 stock for my process.

In carrying out the operation of the process of my invention I subjected hydrocarbon oils to heat treatment at temperatures ranging between 750 F. and 1300 F., more or less, and pressures 20 ranging from atmospheric and sub-atmospheric pressures up to 2000# per square inch, more or less. I

vReferring to the drawing which is one modiilcation of an a paratus suitable for carrying out 25 the process of y invention raw oil supplied through line I and valve 2 is fed by means of pump 3 through line 4 controlled by valve 5, and from there into line 6 to and through the heating l element 1 where itis raised to the conversion temso perature. 'I'he heating element which may consist of an elongated tube arranged preferably` as a pipe coil, or bank of tubes serially connected, is located in furnace setting 8. The oil at the conversion temperature passes through line 9, controlled by valve I0 into the reaction chamber I I. The vapors leave the reaction chamber II, pass through line I2, controlled by valve I3 into dephlegmator I 4 where the vapors are partially condensed forming a condensate of intermediate boiling point referred to as reflux condensate.

A portion or lall of the raw oil may be passed into the dephlegmator, through line I5, cone trolled by valve I6, where it meets the ascending vapors condensing the heavier portions thereof 5 and in turn being heated thereby.

'I'he refiuxcondensate, plus the raw oil, passes through line I'I, controlled by valve I8, and is forced by means of pump I9 through line 0,-controlled by valves 20 land 2l, into the heating element l where the refiux condensate undergoes further conversion. I

As an alternate operation I may feed all of the raw oil through pump 3 and line 4 direct to the heating coil 1, and all or a part of the redux linto reaction chamber II.

passing through pump I9 may be diverted through line 22, controlled by valve 23 into the auxiliary heating element 24, located in a sultable furnace setting 25. Preferably the reflux v-is heated to a temperature in excess of 925 F.,

for example about 1050 F. and may follow am? one or be passed in part through each of a number of paths eventually discharging, all or in part, Specifically the oil from heating element 24 may pass directly into reaction chamber II through lines 26, 55, 53, and 9 controlled by valves 56, 51, and 54. A portion or all of the oil thus fed may be diverted from line 55 through valve 58, in line 49, into heating element 5I which is located in a suitable furnace setting 52. The oil passed through heating element 5I, is therein subjected to further heat and is discharged through valve 59 into line 53 where it combines with that portion, if any, of the oil fed directly to line 53 through line 55, thereafter passing through valve 54 into line 9 and thence into reaction chamber II. A separate reaction chamber or separatin zone may be employed ahead of reaction chamber I I in which case the oil discharged from heating element 24 may pass through line 26 and valve 21 into chamber 28 Where vapors and liquid may be separated, the liquid being withdrawn through line 29 controlled by valve 30. The vapors from chamber 28 are withdrawn through line 3l and valve 32 and may thence pass direct- -ly through line 33, valve 34 and line 9 into reaction chamber II or may be directed all or in4 part through valves 50 and 58, in line 49, and thence through the heating element or reconversion zone 5|, discharging therefrom through valves 59 and 54, in line 53, into line 9 and thence into reaction chamber- II.

The unvaporized liquid residue from reaction chamber II may be withdrawn through line 64 controlled by valve 65 and vapors from this zone pass through line I2 and valve I3 into dephlegmator I4 where they are subjected to fractionation, the heavier condensed portions passing through line I1 for retreatment,4 as already described.

Vapors from dephlegmator I4 pass through line 35 and valve 36 into condenser 31 where they are subjected to condensation the distillate thereafter passing through valve 38 into receiver 39. Distillate is withdrawn fromA receiver 39 through line 40 and valve 4I and uncondensed gas may be released through line 42 controlled by valve 43.

A portion of the distillate from receiver 39 may be withdrawn through line 44 controlled by valve 45 to pump 46 and may be 4fed by Dump 46 through line 41 and valve 48 into dephlegmator I 4 to assist fractionation and to regulate the temperature of the vapors in the top of the dephlegmator I4 thereby assisting to control the nature of the liquid product collected in receiver 39.

Steam may be injected into reaction chamber II through line 6I and valve 60. The steam used is preferably superheated, by means not shown in the drawing, and is introduced for the purpose of forming gaseous components by interaction with the coke which may be formed in this reactionchamber, thus forming water gas according to the well known reaction.y Steam may also be introduced into the oil entering heating element 1 and is supplied through line 62 controlled by valve 63.

In the operation of the process of my invention the relative yields of gas and gasoline (which are the principal products so far as the present invention is concerned) may be adjusted with respect to each other to meet economic conditions.

As a specific example of the results obtained by the operation of the process of my invention using a 26 A. P. I. gravity Mid-Continent topped crude as charging stock and operating in such manner that the oil is heated in coil 1, discharged directly into reaction chamber II, returning reux from dephlegmator I4 to the heating coil 1 and by-passing heating coils 24 and 5I I may produce in excess of 1000 cubic feet of gasper barrel of oil charged. This is equivalent to approximately 25% by weight of the oil charged. In this operation the transfer temperature of heating element 1 is maintained at approximately 940 F. The temperature in the reaction chamber is approximately 870 F. The pressure upon the heating coil and the reaction chamber is approximately 200 lbs. per sq. in. The pressure upon the dephlegmator, condenser and receiver in this operation was equalized with that upon the rest of the system allowing for the pressure drop throughout the system. A yield of approximately 55% gasoline, 10% of pressure distillate bottoms both by volume based on the charge and the remainder of coke amounting to approximately 60 lbs. per barrel of oil charged was made at the same time.

In another operation using the same charging stock the major portion of the reflux from dephlegmator I4 was passed through the heating coil 24 and heated under a temperature of approximately 10007 F. The oil leaving heating coil 24 was discharged into chamber or trap 28 and the vapors and gases Within led into reaction chamber II. The pressure on heating coil 24 was approximately 200 lbs. per sq. in. Heating element 5I was by-passed in this operation. The other conditions of operation were the same as described for the previous example excepting the reaction chamber temperature which was higher in the present example. The yield of gas was approximately 1600 cubic feet per barrel of oil charged, approximately 40% by weight of the oil charged, the yield of gasoline was approximately 35%, the yield of pressure distillate bottoms was approximately 5% and the remainder coke. The anti-knock value of the gasoline was increased considerably in this second operation.

In another operation the vapors leaving chamber or trap 28 after passing through heating element 24 were subjected to a further heat treatment in heating element 5I. In this operation approximately 2000 cubic feet of gas Were made per barrel vof raW oil. This amounts to approximately by weight of' the oil charged. The yield of gasoline was approximately 20% and the remainder coke. The anti-knock value of the gasoline was still further improved. A very small percentage of pressure distillate bottoms was made, the recirculation of distillate in dephlegmator I4 being such as to return most of the products not boiling within the range of gasoline.

While I have given several specific examples ofV operating conditions and yields of products obtained thereby it' is to be understood that these are illustrative only and that my invention is not to be limited in any manner by these examples.

I claim:

1. A process for producing gasoline and gas from heavy hydrocarbon oil which comprises heating the oil to cracking temperature under pressure in a heating zone, discharging the heated oil into a separating zone and separating the aoasss same therein into vapors and residuum, dephlegmating the vapors to condense heavier fractions thereof, passing resultant reflux condensate to a second heating zone and heating the same therein to a higher gasoline-producing cracking temperature than said heavy oil, splitting the thus heated reflux condensate and introducing one portion thereof directly to the separating zone, supplying the other portion of the heated reilux condensate to a gasifying zone and subjecting the same to gas making conditions therein, introducing'the resultant gas to the separating zone, and finally condensing the dephlegmated vapors and separating the distillate from the process.

2. A process for producing gasoline and gas from heavy hydrocarbon oil which comprises heating the oil to cracking temperature under pressure in a heating zone, discharging the heated oil into a separating zone and separating the same therein into vapors and residuum. dephlegmating the vapors to condense heavier fractions thereof, passing resultant reilux condensate to a second heating zone and heating the same therein to a higher gasoline-producing cracking temperature than said heavy oil, splitting the thus heated reflux condensate and introducing one portion thereof directly to the separating zone, supplying the other portion of the heated reux condensate to a gasifying zone and subjecting the same to gas making conditions therein, introducing the resultant gas to the separating zone, injecting steam into the residuum in the separating zone to form water gas, and final- 1y condensing the dephlegmated vapors and separating the distillate from the process.

CARBON P.l DUBBS.

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