US2323206A - Catalytic cracking process - Google Patents

Description

June 29, 1943. l. DE FLoREz CATALYTIC CRACKING PROCESS Filed March 25, 1939 a w QQ f8 x A9 im mlo. NIS ruu Q Mmmm .urnJhU N- w r@ A A s. Nv

Patented June 29,

2,323,2ose` Y UNITED Ys'm'iss- PATENT oFFICE v cArALmo gime rnocsss Y i Luis de Florez, Pomiret, Conn. A Application March Zisetlvo. 264,

2 Claims.

This invention relates' to a. method for production of motor fuel from petroleum and more Y particularly relates to the application of heat and catalytic material to the petroleum for this pur- 'Ihis is a continuation in part of a pending Vapplication Serial No. 208,732, led May-19, 1938,

by the vsame applicant now United States Patent 2,237,339, issued April 8, 1941.

For a further description of this invention reference may be had to the drawing which shows in somewhat diagrammatic form an apparatus for carrying out the process.

The fresh charge enters the system at point Ill at the top oi the fractionating tower I2, passing been formed by contact with the charge in pass- The hot vapors or oil entering the chamber 128 A pass upwardly and meet the steam of heavy matenais discharged by pump u through the une zs. An exchange of h^at occurs, raising the temperature oi the mixture to such a point that the material is eventually distilled leaving solid residue in the chamber 28. The overhead from the chamber 28 passes through 'the line 64 into the fractionator I2 where liquid and vapors are separated, the vapors passing overhead to come in contact with the entering Icharge. The liquid portions accumulate in the base of the fractionator vI2 and are passed out into a stripper 6B. The liquid portions in the bottom of the vessel `I are drawn off in line 68 and constitute a discharged 5 intermediate product. The overhead from the stripper 6B is cooled in cooler 'I0 and discharged .by means of pump 52 into iractionator' 38 comis picked up by pump 1 4 and passed through line ing over the trays. passes out through line I8 having the valve 28, into the stripping column 22. In this vessel the heavy liquid portions oi the charge fall to the bottom and are picked up by pump 24 and discharged through line 25 into the top of the coking chamber 28. The overhead from the stripper 22 passes out through a cooling coil 38 into a receiver 32 where the liquid'portions are picked up by pump 3l and discharged through line 88 into another fractionator 38. The stripper 22 and the receiver 32 may be operated under a vacuum imposed by pump 48.

The overhead from column I2 passingA out through line 42 passes into the' base of the fracpleting the cycle at this point.

Aslurry containing a solid catalytic material which has been prepared in the mixing system 'I2 I8 to any one of a plurality of discharge pointsV u 18, 80, 82 or 84. The branches of the pipe 'I6 the solid catalytic material, itis mlxed'wlth a.k

tionator 38. The vapors rise through this vessel which is equipped with suitable trays, not shown,

A portion of the.

tionator ll composed of the liquid portions of the overhead discharged from pumps 34 and!! is Apicked up by main circulating pump Il and dis- 1 charged through line 58 into the heating coil 58 of the heater 60. `This material is-then heated in me con as and discharged through the une ,s1

havingv valve 82 into the reaction chamber 28. 55

mutable liquid suon as water or a light hyiiro-` carbonadmittedtothemixerat85andinas1if-- terial is rst heated and separated into light and heavy constituents inthe fractionator I2', the lighter constituents entering into the circulation through the heating coil 58 and the heavy constituents being injected into the reaction coking zone directly. In the passage through the heater which has been broughtinto the system in a liquid or semi-liquid form is subjected to a rela- Atively high heat and the liquid `which carries the catalytic material isvaporized or otherwise separated iromuthe catalytic material allowing this latter to become free in contact lwith the material under treatment. After conversion occurs. lighter or more' volatile hydrocarbons are formed and likewise polymerization products are formed. The polymerization products tend to remain in contact with the catalytic material and in turn the catalytic material will tend vto be enveloped by tarry particles which will separate themselves .out in the reaction chamber and gradually be recracked products to another reaction drum pre-4 viously cleaned. The bottom section of the primary dephlegmating tower I2 may be suitably cooled to produce a heavy liquid condensate which 5 is withdrawn from the bottom to a stripper 88 where it is dashed into an overhead vapor. The vapor is condensed and cooled in and pumped back into the fractionating tower 88 for further treatment. An intermediate oil liquid auch as duced'to a solid coke-like material to deposit inv l0 fuel oil is withdrawn from the bottom of the the cokek chamber 28 from which they are re moved by a suitable coke drilling or removing' mechanism indicated in the drawing as 88.

Thus it will be seen that theA catalytic material is inJected intothe system. contacted with the materialunder treatment and removed from the system in a continuous manner. While only one coke chamber 28 has been shown. in order to make the operation continuousa plurality of auch chambers will preferably be used with suitable connections so that one chamber may be shut of! to be cleaned while another is connected in the system in a manner similar to that disclosed in the aforementionedn pending application Serial No. 208,732. 4

This operation may be carried out under varylng pressures and temperatures depending upon A the material to be treated and the type of cata- Lvst employed. The injection of the catalyst may be made at different points togvary the time in which it is in contactI withrthe materialunder treatment. As an example ofthe operation of the invention, a charging stock such as crude oil, reduced crude, gas oil, or heavy naphtha, is contacted in the upper section of ,a primary dephlegmating tower with cracked vapors from the system, whereby the lighter constituents of the.

charge are vaporized and 'the heavier components of the cracked vapors condensed. 'I'he condensed liquid is withdrawn through line I8 to a vacuum stripper 22 for further reducing to a1 heavy liquid which is withdrawn from the bottom of the stripper and pumped through line 28 to the top of the reactionl chamber 28. The vapors from the stripper 22 pass overhead and condense in 80, after which they are collected in 82 andpassed to the fractionating tower 28 where they are blended with the liquid condensate and I pumped through line 88 to the heater 88 which is maintained under a pressure of from 100to 200 In the heater the temperature of the ing withA the catalyst 'slurry which may be admitted, as has been pointed out hereinbefore, at

`itny one of several points. Thehot products in the vapor phase are then transferred to the reaction drum 284 where they ,are'intimately' contacted with the catalyst. After contacting with vapors, the clay settles out in the lower portion i .lower portion` of the reactin drum with coke formed therein is intermittently removed by cut- .ting out one reaction drum and passing the o stripper through line 88.

The process which has been described permits I the withdrawal of an intermediate liquid product which is not returned to the coking zone, thus decreasing the-quantity of coke made per barrel This intermediate liquid product repo! charge. resents a highly degraded material which if returned to the coking zone would deposit a very large proportion of coke and would produce a relatively large proportion of gas. The conversion of such a material is far less favorable than the conversion of the material selected for retreatment. This degraded material is more useful in the *form of an intermediate distillate suitv v' -able for f-uel oil than as a material to re-treat.

Obviously, manymodiiications and variations of the invention as above set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed ss are indicated by the appended claims.

slurry of a catalyst and a carrier liquid with the heated oil, subjecting thev mixture of oil andl catalyst to reaction in an enlarged conversion zone, withdrawing vapors from the conversion zone, separating from 'these vapors a heavy liquid 40 which is withdrawn from the system, contacting fresh charge with the uncondensed vapors in a fractionating zone thereby condensing a portion of the vapors and vaporizing a portion of the charge, passing a mixture oi.' unvaporized charge and redux condensate from'said fractionating lzone toa stripping zone maintained under vacuum and there stripping said mixture'to form vapors and a residuum, condensing said vapors, recycling said residuum to said conversion zone.

passing a mixture of fresh `charge vapors and conversion zone vapors from the 4fractionating zone to a second fractionating zone, passing the condensate formed fromY the vapors from the stripping zone to said second fractionating zone,

'55. iractionating thevapors and condensate in said second fractionating zone 'to form gasoline and a clean recyclev stock. and Ireturning said clean recycle stock to said heating zone. l

- 2. The process of claim 1, in which the heavy 0 liquid which is withdrawn from the system is iirst flashed into an overhead vapor and said vapor condensed and passed to the second fractionating zone.

. LUIS nl FLOREZ.

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