Патент USA US2408587код для вставки
OEHKL'VI HUUU F 195411 OR 294089584 Oct. l, 1946. A. D. SMITH 2, ,584 HYDROCARBON CRACKING PROCESS WITH SUCCESSIVE ADDITION OF ADSORBENT Filed Feb. 10, 1945 #N Uil-NNUU Patented Oct. 1, 1946 i 2,408,584` UNITED STATES PATENT OFFICE 2,408,584 HYDROCARBON CRACKING PROCESS WITH SUCCESSIVE ADDITIONS 0F ADSORBENT Arthur D. Smith, Park Ridge, Ill., assignor to g?‘nkins Petroleum Process Company, Chicago, Application February 10, 1945, Serial No. 577,217 In Canada September 27, 1944 6 Claims. 1 (Cl. 196-55) 2 'I'he invention relates to an improvement in process for treating hydrocarbons in the presence An important object of the invention is to pro vide, through such immediately above described of certain ilnely divided adsorbents and particu release of structural Water, a corresponding con tinuous fresh contact surface in the thus pro duced dehydrated or partially dehydrated adsorb ent, partly through the formation of smaller par ticles of adsorbent due to the -di'sintegrative ef fect of the escaping Water vapor, and partly through the formation of microscopic pores and larly to a process for contacting petroleum hydro carbons, lying outside of the boiling range of gaso line and while obtaining under transforming con ditions of heat and pressure, with intimately dis persed ñnely divided hydrous mineral adsorbent possessing a structural Water content substan tially vaporizable under the transforming condi tions employed. fissures in the original particles. A corollary object of the invention is to provide, through such immediately above described for mation of fresh contact surface, a corresponding continuous augmented nascent adsorptive and/or : catalytic effect; the advantage of such improve A known process comprises among other fea tures continuously subjecting a petroleum oil, in which is suspended a finely divided mineral ad sorbent towards carbon and carbon-forming sub stance, to cracking conditions of heat and pres sure, whereby carbon and carbon-forming sub stance produced during the reaction is associated with the adsorbent and prevented thereby from depositing on the walls of the cracking apparatus 20 employed. Among suitable adsorbents recited in such process, is the hydrous mineral adsorbent calcium hydroxide; such being particularly an adsorbent towards -sulphur-bearin asphalte s, the ultimate degradation products of which are carbon and hydrogen sulphide. 'I'he latter is neu tralized by the hydroxide and the contaminating ment being readily apparent where the dehy drated or substantially dehydrated adsorbent, for exa „ntoni -actmcatalytically in improv ing the yieldî‘?d/or quality of desired light hy drocarbons. \\ Another object of the invention where, for ex ample, the highly basic calcium hydroxide is em ployed as the hydrous adsorbent, is to provide, through the above described increased active con tact surface in the adsorbent particles, for inten siiied formation of calcium sulphide from hydro gen sulphide commonly obtaining in petroleum transforming operations; the continuous nascent corrosive effect of the hydrogen sulphide on the metal of the apparatus substantially reduced. It liberation of structural Water increasing the ac has been more recently discovered that the effl 30 tivity of the reaction. ciency of such decontaminating action is in Another object of the invention ancillary to the creased by release of structural Water from the immediately preceding is to reduce, through such calcium hydroxide during the reaction, such re above described intensified formation of calcium lease producing fissures and pores in the hydrox sulphide, the contaminating corrosive effect of ide particles: or in short, forming additional ef 35 hydrogen sulphide on the metal of the trans fective contact surface favorable to hydrogen sul forming apparatus. phide retention. While the general phenomenon Of the several hydrous adsorbents that may be of structural water release is inherent in the above employed to develop the optimum in fresh active described process, the actual percentage evolved, surface contact through release of structural and the stages in which evolution occurs, will vary 40 water, may be mentioned bentonite, bauxite and with the cracking conditions imposed and the the hydroxides of the alkaline earth metals, but purity of the calcium hydroxide employel.; all I prefer to employ bentonite Where catalytic ac militating against the continuous nascent release tion is a paramount issue, calcium hydroxide of structural water during the entire or suo'stan where intensified chemical action towards hydro tially the entire cracking phase, and thus against gen sulphide is wanted, and a mixture of the two the optimum in eiiiciency of adsorptive effect. where both effects are desired. The present invention is an improvement over In order that the invention may be more readily the foregoing in that it provides not only for the understood, reference is made to the accompany continuous or substantially continuous release of ing drawing of a flow diagram embodying a con structural water from a hydrous adsorbent dis 50 crete example of one of the many operative con persed in fluid hydrocarbon subjected to trans ditions to which the invention may be applied. forming conditions of heat and pressure, but for Referring to such drawing, let it be assumed such release during the entire or substantially the a petroleum hydrocarbon, for example, gas oil, entire period such hydrocarbon is subjected to as supplied from the tank I through the line 2, such transforming conditions. is charged by the pump 3, through the line 4, 3 4 to the bubble tower 5, and that a composite virgin gas and recycle oil therefrom, obtaining at '710° F. (an incipient cracking temperature) and flow ple per temperature rise being carefully recorded. 'I'he results of such a test applied to a techni cal grade of calcium hydroxide of high purity un der the transforming conditions previously de scribed in the concrete example follow: ing through the line 6 to the hot oil pump 1, is introduced by such pump through the line 8 to the transforming furnace 9. Let it be further assumed that the oil, obtain ing under 400 lbs. pressure, enters the radiant coil I0 disposed in the'furnace 9, requires three minutes for passage through such coil and dis charges therefrom at 910° F., that the elliuent . Time Temperature Percent struc Percent or total interval, differential, tural water (2g?ìä)wâîggc' l 710- 800 1. 79 7. 37 minutes F. released released 10 l from coil I 0 enters the convection coil II, re l l 800- 850 6.17 25. 39 1 l 850~ 910 7.17 29. 50 quires ñve minutes for passage and discharges` 2 1 910- 950 0. 47 l. 93 therefrom at 1060° F., that the oil stream respec 1% i 950-1000 0. 00 0. 00 1% 3 1000-1060 0. 00 0. 00 tively obtains at 950° F. and 1000° F. at return 15 bends I2 and I2', that the time factor between 8 710-1060 16. 60 64. 19 910° F., and 950° F. is two minutes, between 1 Radiant section period. 950° F. and 1000° F. one and one-half minutes, 2 Convection section period. and that the final eiiluent from said convection coil is released under reduced pressure through 20 From the above it will be noted that under the line I3, as controlled by the pressure release the time factor involved, release of structural wa valve I4, to the evaporator I5 (after first hav ter from the hydroxide in question practically ing its temperature lowered in the heat ex ceases between 910° and 950° F. A second dehy change means I6) to incipient transforming con dration test is therefore conducted on a. fresh ditions; it fbeing noted that `the oil is thus sub 25 sample of the hydroxide, the chrome alloy tube jected for a total period of eight minutes to trans being previously preheated t0 910° F. before in forming conditions of heat and pressure embrac serting the sample, and the time factor between ing a range of 710° F.-l060° F. Heavy residual 910° and 1060° F. maintained at five minutes. oil containing spent adsorbent, whose introduc Such test, due to the higher initial temperature tion yto the system will be subsequently discussed, 30 involved, will generally result in substantially is withdrawn from the Ibottom of the evaporator the same total quantity of water being expelled through the line I1 and cooler I8, as controlled as in the first preliminary test; occasionally be |by valve I9, to the fuel oil tank 20; while light tween the range of 910° and 1060° F., but more fractions separated in the evaporator pass often between 910° and 1000° F., thus requiring through the line 2I to the bubble tower 5 in 35 a third addition 0f hydroxide to bridge the final which gasoline and distillate vapor are separated gap of aqueous evolution between 1000° and from recycle oil; gasoline passing through the 1060° F. line 22 and condenser 23 to the tank 24, distil Therefore, to comply with the invention and late through line 25 and condenser 26 to the ensure a continuous release of structural water tank 21, and the recycle oil admixed with the 40 from the 0.6 lb. of hydroxide over the entire or virgin gas oil introduced through the lbubble tow substantially the entire 710°--1060° F. range, it er, forming the composite charging stock to the will be necessary in the first case to continuously transforming coil in the manner as above de introduce the hydroxide in two portions, one, scribed. when the oil stream obtains at '710° F., the other While a'ny one, or a mixture of two or more between 910° F. and 950° F.; in the second case, of the previously mentioned hydrous adsorbents, in three portions, with the oil stream obtaining depending on the adsorptive and/or catalytic at '710° F., between 910° F. and 950° F., and at effect desired, may -be employed under the above 1000° F. respectively. To further ensure the described operative conditions, let it be further optimum in adsorptive and/ or catalytic effect, the assumed a technical grade of calcium hydroxide said portions of adsorbent should generally lie in of high purity is actually used in the above case, the same ratio to the total quantity introduced, in quantity 0.6 lb. of hydroxide per bbl. of oil as the corresponding time factor per temperature charged to the coil; the specific problem being interval of injection is to the total time factor to so introduce such quantity of hydroxide as to of the transforming conditions employed. ensure a continuous nascent release of structural Introduction of adsorbent to the system may be water therefrom over the entire or substantially effected in dry form dispersed in a hydrocarbon the entire transforming range of 710° F.-1060° F.; vapor carrier such as heavy naphtha vapor; or or otherwise expressed, to ensure the optimum in as a slurry suspended in a carrier oil conveniently fresh active contact surface of adsorbent over of the same grade as to be transformed. such period. GO Referring again to the accompanying drawing: To achieve such effect, I first subject a care 28, 29 and 30 represent a plurality of any num fully weighed sample representative of the ad ber of slurry tanks as may be desired, such tanks sorbent to be employed, say 5 grms., to a pre being ñtted with mechanical agitating means liminary dehydration test in a current of dry (not shown) and supplied with carrier oil hydrocarbon gas such as methane; the test sam through the line 3I, by pump 32, from tank I; ple preferably obtaining as a thin layer in a. valves 28', 29' and 30’ serving to control the flow platinum boat disposed in a chrome alloy tube of such oil to said tanks. The latter are con heated by an electric furnace, with the heating nected through the grid manifold 33, as controlled tube connecting to a water cooled condenser fitted by valves 34, 34', 34", 35, 35', 35", 36, 36', 36”, with a graduated receiver. The above test is 70 to the separately operated high pressure pumps further conducted under the pressure, tempera 31, 38 and 39; such arrangement permitting feed ture and time factor of the transforming rela from any one or all of said tanks -to any one or tions to be imposed on the hydrocarbon in which all of said pumps. 'I'he latter are further iitted . the adsorbent is to be employed; the percentages with individual automatic controls of a well of structural water released from the test Sam known type (not shown) which can be set so -that ötAHUH liUUil 5 2,408,584 the .pumps will continuously deliver predeter mined volumes of slurry to the transforming coil through lines 40, 4| and 42, respectively equipped with check valves 40', 4|' and 42'; such injection lines being depicted in .the accompanying drawing as connecting to said coil at the predetermined points described in the concrete example. In such example, the slurry may be batch prepared 6 mixture, that under the time factor involved, such aqueous evolution occurs in the said higher temperature brackets, thus closing the gap re quired to be ñlled by multiple introduction where a single grade of hydroxide is employed. In like manner to the specific example given for calcium hydroxide, preliminary dehydration tests may be applied to any of the hydrous ad in tanks 28 and 29 and withdrawn from one tank sorbents mentioned herein, orto those of similar while the other is being reillled; or it may be 10 class, and from the structural water release data pumped entirely from one tank, i. e., tank 28, which is continuously supplied with carrier oil and calcium hydroxide in the proper proportions. Further assuming such slurry to be of a concen thus obtained the number of multiple introduc tions and points of injection necessary lto effect a substantially continuous aqueous release over an entire predetermined transforming range can tration, say of 0.75 lb. of hydroxide per gallon 15 be readily determined. It will also be aplliarentl of carrier oil and to obtain in tank 28, it may be to those skilled in the art that increments of two respectively introduced therefrom by pumps 3l or more dliferent adsorbents of the class de and 38 to the radiant and convection sections of scribed, such as for example, bentonite and cal said coil at the herein described predetermined cium hydroxide, may be introduced pre-mixed at temperatures, after closing valves 34', 34”, 35', 35", 36, 36', 36" and opening valves 34 and 35. ’I'he said pumps 3l and 38 may be set to contin 20 one or more predetermined points of the trans nforming coil, or separately injected at a plu rality of points; the specific point or points of uously deliver their respective slurry increments injection depending on preliminary dehydration in the same quantitative ratio as the time fac tors given in the concrete example; i. e., so that data and the specific objective .to be obtained, Within the thesis of effecting a, continuous or 0.225 lb. and 0.375 lb. of calcium hydroxide (total substantially continuous release of structural 0.6 1b.) per barrel of oil charged to the coil, will water from the adsorbent introduced over the respectively enter said radiant and convection particular .transforming conditions involved. sections. By opening valve 36 and thus permit The invention is further not limited to the ap ting pump 39 to function, increments of 0.225 30 paratus, pressures, temperatures, time factors, lb., 0.200 lb., and 0.175 lb. of hydroxide (total 0.6 quantities and ratios disclosed herein which are lb.) may be respectively injected under the time to be considered as illustrative only of one set of factors and at the coil section points described conditions comprehended by the invention, and herein; although it is to be understood that ln what I claim as new and desire to protect by 1ct crements of adsorbent introduced may be in dis 35 ters Patent is: ‘ proportionate relationship to the time factors 1. Process of minimizing corrosion in an oil involved. cracking still, which comprises: supplying to the It is to be further understood the percentages of stream undergoing heating, successive increments structural water released for a given temperature of an adsorbent consisting essentially of calcium/ in 4the above described preliminary dehydration 40 hydroxide and adapted to react with corrosive tests are illustrative only, since another calcium compounds generated by decomposition of ingre hydroxide of practically the same technical purity dients in the oil; and timing said increments so and tested under identical conditions, but de as to add each increment at substantially the time stone, or calcined‘ and/or slaked at a different that the previous increment ceases to liberate rived, for example, from a finer grained lime 45 structural water. temperature, or rate, may show figures at vari 2. Process of minimizing corrosion in an oil ance from those given; therefore the necessity for cracking still, which comprises: supplying to the separate preliminary dehydration .tests on cal stream undergoing heating, successive increments cium hydroxides from different sources to deter of an adsorbent consisting essentially of a, finely mine their proper injection points. In any case, 50 divided hydrous mineral adsprlìent having the however, no unit lot of calcium hydroxide has characteristic of liberating its structural water been found, that when continuously introduced, will release structural Water over the entire or gradually when heated to oil-conversion temper atures; and timing said increments so as to add substantially the entire transforming conditions each increment at substantially the time that the herein disclosed; hence .the need of multiple in 55 previous increment ceases to liberate structural troductions of such hydroxide to attain the water. ' optimum in fresh active surface contact and the 3. Process of minimizing corrosion in an oil ensuing benefits thereby. cracking still, which comprises: supplying to the As a simpler alternative to multiple introduc stream undergoing heating, successive increments tion of a single grade of calcium hydroxide, one 60 of an adsorbent consisting essentially of calcium continuous injection may be employed of a mix hydroxide and adapted to react with corrosive ture in suitable proportions, as determined by compounds generated by decomposition of ingre preliminary dehydration tests of the order herein dients in the oil' timing said increments so as to described, of calcium hydroxide of the technical add each increment at substantially the time that purity discussed and a calcium hydroxide `con 65 the previous increment ceases to liberate struc taining over 1%, and preferably between 3 and tural water; and pre-determining the timing for 8%, of calcium carbonate, that will release struc said increments by exposing a sample of said tural water over substantially the entire trans adsorbent to a time-temperature and pressure forming range herein disclosed. Such phenom history substantially the same as in the still, under enon is due to the fact that the presence of a 70 an atmosphere of hydrocarbon gas. relatively small quanti-ty of carbonate, or car 4. A process according to claim l in which a bonic acid derived therefrom and released dur i fraction of calcium hydroxide contaminated with ing the reaction in the high temperature brack a significant percentage of calcium carbonate, up ets. so retards the evolution of structural Water to 8%, is included in the materials supplied. from the carbonate-containing component of the 76 5. In an oil cracking process in which the con 2,408,584 7 tinuous progressive exposure of fresh reactive surfaces of adsorbent lime is advantageous, the novel procedure of making successive additions of calcium hydroxide, and timing the successive ad ditions so that each addition is made substantially at the time that the previous addition ceases to evolve water. 8 novel procedure of supplying the adsorbent in the form of particles which gradually and pro gressively evolve vapor, and by such evolution clean and expose fresh reactive surfaces during the period of vapor release; and timing the suc cessive additions so that each addition is made substantially at the time that the previous addi 6. In an oil cracking process in which the con tion ceases to release vapor. tinuous progressive exposure of fresh reactive surfaces of an adsorbent is advantageous, the 10 ARTHUR D. SMTI‘H.