US2174510A - Method of continuously hydrofining carbonaceous vapors with solid sulphur sensitive catalytic surfaces - Google Patents

Description

Oct. 3, 1939. M, G,A GWYNN i 2,174,510

METHOD 0F CONTINUOUSLY HYDROFINING CARBONACEOUS vAPoRs WITH SOLID SULPHUR SENSITIVE GATALYTIC SURFAGES 2 Sheets-Sheet l Filed Marchv 8, 1957 mum FINN@ camini R O T N E v m oUS VAPoRs 2 Sheets-Sheetl 2 M. G. GWYNN Filed March 8, 1957 WITH SOLID SULPHUR SENSITIVE CATALYTIC SURFACES METHOD 0F coNHNUoUsLY HYDROFINING CARBONACE Oct. 3,

Size- GSNM Amanmobo-z Patented Oct. 3, 1939 UNITED y STATES PATENT ol-FICE METHOD OF CONTINUOUSLY HYDROFINING CARBONACEOUS VAPORS WITH SOLID SULPHUR SENSITIVE CATALYTIC SUR- FACES 'This invention is a continuation in part of my pending application Serial Number 650,997 entitled Method of refining hydrocarbon distillates, filed January 10, 1933, now Patent 2,073,578

5, granted March 9, 1937.

My invention relates to the refining of carbonaceous vapors with solid sulphur sensitive catalytic surfaces under novel gradient conditions, particularly to the hydroning of light petroleum 10. distillates (and those free or freed of asphaltic materials) which refining may be used alone or in conjunction with the old methods of refining.

The essential feature of this hydroning is the use of solid sulphur sensitive surfaces compris- 152 ing a catalytic metal, e. g., nickel, under gradient and substantially nonpyrolytlc conditions, particularly gradients of temperature and hydrogen excess or their equivalents. Two forms of the invention are described, onethe stationary cat- 2'0 alyst form, and the otherV the .countercurrent form. When present, labile sulphur compounds are removed or converted into less troublesome components, and gum forming unsaturated compounds converted to useful compounds without 25 loss of yield. The -process eliminates wholly or in part the use of sulphuric acid.

In either form the inventionis carried out in the vapor phase preferably under a gradient of temperatures and of hydrogen excess. Inthe 30 countercurrent form the catalyst is preferably continuously moved countercurrent tor the mixture of carbonaceous vapor and hydrogen as shown in Fig. 3. In this form the catalyst becomes progressively spent, the most spent portions 86 are preferably contacted with` the unhydrofined carbonaceous vapor, and the least spent or fresh portions are preferably contacted with those carbonaceous vapor hydrogen mixtures most completely hydroned.

40 Also contributing to my invention is one or more of the following: the division of the hydrofining into two different operations; the separate treatment or selection of fractions Within a distillate; effective means for preparing and reac- 45 tivating the catalytic surface .the selection of effective nonhydroning treatments to -be used in connection with the hydroiining, such as the subsequent addition of antioxidantand/or antiknock reagents. Later described are examples of these I use the term hydroning generically to com-4 prise hydrogenation and/or desulphurization, 55' generallypboth when sulphur is present. Sulphur immune catalyses are characteristically liquid phase processes requiring high pressures and pyrolytic temperatures, whereas my hydrofining is preferably in the vapor phase at pressures below those generally used above, and at low tempera- 5/ tillates are preferably free of ultra microscopic colloids, depositing carbon, marked coloration, l5 and even very high molecular weight hydrocarbons. It is not necessary that the distillates be water white. Vaporization from a vaporizing chamber tends to rid a distillate of extreme heavy ends, oxidation products due to age, and other impurities harmful to the catalyst. I also nd that the unsaturates themselves prematurely deactivate a metallic catalyst unless contacted under my gradient conditions.

My gradient operation maximizes and xes sulphur poisoning. This is a necessary deactivation, a purpose of my invention.` At the same time the gradient operation minimizes the unnecessary or premature deactivations. These things are marked advances over the prior art, which has been dominated by the traditional phase rule practice of a constant temperature, pressure and contact time within a given operation.

I find that reactant and catalyst activity are complemental to temperature, and it is the product of activity and temperature which I strive to maintain constant or relatively so. Neither of these factors can be changed without changing the product thereof, the latter apparently being 40 the essential factor so far as constancy ,is concerned. The time gradient of temperature as discussed later is ascending, and compensates the progressive decrease of catalyst activity, for which I have developed a measure as indicated in Fig. 1.

My hydroilning may be carried out to various extents. V A relatively small' extent or duration of contact is generally sufficient to remove th more labile impurities, such as mercaptans, and so render the product doctor" sweet. The olefines l50 need not be completely l'lydrogenated.,` Other treatments may be used in conjunction with my hydrofining such as those means known to the art. If for reasons of economy, minor quantities of gum forming unsaturates remain after my hydroiining, these may be removed or inhibited.' by other means. The contact with liquid caustics and the addition of antioxidants are useful aftertreatments to my hydrofinlng. For example li may add the soluble and gum inhibiting derivatives'o'f` para-aminophenol in very small quantities to a motor fuel distillate after my'hydroiining when the olenes are inconipletely hydrogenated. lExamples of such derivatives are monobenz.-paraaminophenol, dibenzyl para-aminophenol, parahydroxyphenyl morpholine, and in a -quantity for instance on the order of 0.005%.

-The productof my liydrofining is extraordinarily responsiveto the subsequent addition of fractional percentages 'ofl reagents such'as antioxidant and antiknock reagents. this being one of the purposes of tlieinvention. My hydrofining `selectively and in general entirely removes com-v ponents which are apt .toprecipitate-or onset the eil'ect of antioxidants, and which are proknock. The more labile sulphur compounds, particularly polysulphides, are markedly proknock and often prooxidant. My hydrofining also'retains and improves many of the natural gum linhibitors of the vdistillate". `Thus I may use antioxidants or in A .Y-h'ibitors ofunusually low solubility. -I may also use the somewhat more soluble inhibitors or anti-4 oxidants with less danger of .precipitation or.

change; 'The more powerful gum inhibitingantioxidants are amongfthose of the least solubility in hydrocarbon motor Afuel, for instance para ethyl-aminophenol orpyrogallol. Other of the less simple phenols and/or nitrogen vderivatives of benzenes may be used.

'The 'usual motor fuel distillate lshed sweetened with alkali in some form. The utmost care is requiredV to eliminate traces of. alkali from the -nal product; Yet traces of alkali precipitate orv arevotherwise detrimental to some ofthe bestgum inhibitors such as-monobenzyl parav aminophenol. 'Myhydroned-product is free from traces of alkali as well as free from pre-I cipitating sulphur compounds.

YDiagrainmatically shown in thedrawings are three forms of-apparatus or control for sulphur sensitive hydroning `under gradient conditions. Fig. 1 represents four types of time gradients of temperature and the relation of these to catalyst 1 activity. The gradients may be used directly in the stationary catalyst form'of my invention.`

or fresh catalyst at-the rear or cool stage of contact, comprising relatively countercurrent operation with either continuous o r .discontinuous ini troduction of the catalyst.

. 'A series of temperatures as ordinarily used, in the prior catalytic art is herein termed a space oliv gradient, in distinction to a time gradient-which represents the increase of average temperature of the space gradient if any with increasing deactivation of the catalyst as a whole. A timel series of temperatures is anascending gradient. I use the term gradient to mean discontinuous steps or changes as well as continuous change. The space gradient is ascending and/or descending. The usual space gradient is ascending but controls reactant rather than catalyst changes. A descending gradient of temperature for the andere 'approximately' equalize the hydroiining in each is .generally iingather with-a sary catalyst deactivation vapors is useful. during relatively coimtercurrent contact with 'fresher andfresher catalyst. v The space gradient is an essentially instantaneous gradient. consisting of a series of temperatures whicha molecule of the vapor undergoes during its short period of catalyst contact. This gradient is generally of theA widerv range in the lowv temperature. liquid phase, hydrogenating v rather than desulphurizing operations.

The time gradient constitutes that rise of temperatures as a whole over a single cycle of active life .of the catalyst. It is generally of the wider range in the vapor phase, and in desulphurization rather than hydrogenation operations.

My gradient conditions tend to relatively or offthe stages of hydroiining; particularly in the stages when Vthe catalyst is quite active. When vthe catalytic surfac arenearly spent it may be impracticable to maintain the formerhigh level n -of hydrotlning. The

resulting hydroned product may be further vtreated however.'- droflnedtobringituptothe i I prefer livtihvdronne-motor fuel distillate.' atv least until the distillate is test. I also Prefer to incompletelyhydronne.. even as a standard-.1 An incompletely hydroned product may be lfurther with solid sulphur -sensitivecatnlytic surfac, preferably in fewer stagesthanthe first hydroning. For-in'- fstance, anascendingspace gradient of negative acceleration in theliquidphaseland with a'nick'el catalystand at an-'elevated temperature, e. g.. l C., constitutes an effective means of hydroiining the iight distillates with a minimum change in knock rating and solvent power, especially in distillates yhigh in unsatura and comparatively low in sulphur.

1 The .relative or approximate ecualization of. hydroilriingl allows the catalyst to work at a 'relativelyconstantor uniform rate, -whicli minimizes unnecessary catalyst deactivation and side l reactions. These eiIects, ltoor speeding of neces'- y (sulphiding) and main reactions, appear tofbe only accomplished under my gradientconditions. Time gradients of tem--v perature are the principal but not the only v.means o f attaining my `gradient conditions. Differential regulation of the hydrogen excess and pressure is useful. In both the stationary and y countercurrent'form of my invention the temperature and the hydrogen excess is regulated.

of pressure may beeifectively used together in the stationary form.

sweetto'the-dcctorl Gradient: of temperature, offhydrogen excess and In carrying out my invention, I note a tend e'ny vfor one carbonaceous molecule to adsorb on each sulphur sensitive catalytic unit, be that a metal compound or atom. The metal after conversion to sulphide ,or oxysulphide tends to iining at constant preure, bothdesulphurizing and hydrogenating diminish in the iinal and hotter Stages' 0f hydIOning. Along with this I have noted an apparent markedl increase in yield above theory.' This was found to. be due toa decrease' in vthe adsorption of carbonaceous n compounds on the catalytic surface, probably an index of a decrease intrue contact time. By decreasing the hydrogen excess and/or increasing the pressure, the apparent abnormality of yield is corrected, and the desulphurizing and hydrogenating diminution is checked. Increasing the pressure alone aids the hydrogenating more than the desulphurizing.

As will be noted in the examples, the time gradient range for this work is preferably more than C. with nickel and like catalysts, though less with the low activity catalysts. Fresh nickel will actively desulphurize distillate vapors below 200 C., and will be useful at 300 C, and greater when near spent. The preferred range of the temperature gradients in my invention is between about 20 C. and 200 C. The range of the time gradient in the stationary form of my invention is about proportional to the catalyst activity under otherwise similar conditions.

Fig'. 1 diagrammatically shows several types of time gradients directly useful in the stationary form of my invention and indirectly useful in determining the cooling curve for the countercurrent form. Fig. 1 also shows lthe relation between these gradients and quantitative catalyst activity. The ordinates represent temperature in degrees centigrade, The unit full temperature range is C. The abscissae represent time, which may vary in each case depending chiefly on the` percentage of sulphur removed from the distillate. For instance a typical unit time is one day. In the cubic parabola 6, with unit of time one day, the total time from 85 C. to 325 C. is two days, and the equation is where T is any temperature between 85 C. and 325 C., and t is the time in days from the start at 85 C. The parabolic exponent is 3.

In the curve 6 the ordinate is the tirne when the catalysis reaches 205 C. and the equation for the upper right hand branch of the curve is T 205 C. 120 C. wherev t 205 is the time after reaching 205 C.

Likewise in the parabola 4, neglecting negativeY legs of the curve, the equation is 120 C. To scale with the cubic parabola 6, the unit time for the parabola 4 is somewhat more than 2 days. The parabolic exponent is 2. v

1n the intermediate curve 5, herein" termed the mean hyper parabola, the parabolic exponent is 2.5. rilnis is a very useful form.

A parabolic exponent of unity would represent a straight line parallel to the abscissa at T=325 C. This is a gradientless curve 2. 1ntermediate to this extreme and unreal form and the parabola is the mean hypoparabola 3 of parabolic exponent-1.5.

There are all gradations betwen the extreme unreal forms. rIhe gradations between 6 and 4" are'generically herein termed hyperparabolic.

The full range of curve 6 is shown as 240 C.; of curve 5, C.; of curve 4, 120 C.; of curve 3, 60 C. Dividing the full range of each by 120 C. gives 2, 1.5, 1, 0.5 respectively. This is the` same as the parabolic exponent less one,

which is a measure of curvature complexity, and in my belief a measure of the fresh catalyst activity or sensitivity. The practical ranges are generally less than the full ranges. Temperatures somewhat above 325 C. may be used when hydroflning motor fuel or such distillates. 250 C. to the temperature at which substantial pyrolysis occurs, represents a practical upper limit. When the catalysis is at the abscissa, the catalyst activity is unity, irrespective of the state of the catalyst, whether fresh as at the beginning of curve 4 or half spent as at the lmid point of curve 6. The ,abscissa may vary substantially from 205 C. Initial desulphurizing apparently occurs by means of adsorption of the sulphur compound to the catalytic suface, At temperatures higher than the abscissa temperature, this adsorption is followed by partial desorption and chemical reaction to form a sulphide of the catalytic metal.

The theoretical speculations herein are mainly for the purpose of guiding actual or prospective practitioners of the invention, particularly in the ne points thereof. The invention is practical and useful regardless of the absolute truth or fallacy of the speculations, and is not to be undulylimited by the theory or examples.

It appears however that the general complexity and range of the time gradient is a measure of and is determined by the activity or sensitivity of the fresh catalyst to an approximation at least.

These Fig. 1 curves are useful in determining the cooling in the countercurrent form of my invention. For the same fresh catalyst activity, the complexity of the countercurrent curvature is generally simpler, that is the graph is straighter. Both the practical and full ranges appear to be correspondingly less. The countercurrent form of my invention tends to maintain the activity of the catalysis relatively constant throughout the contact. I may regulate the cooling to compensate the net increase of the catalyst activity from which-the reactant activity has ben subtracted. reactant activity is not subtracted.

The practical'limits of catalyst activity in the fresh state for my invention appears to be greater than about 0.5 but less than about 1.8. An activity of 2.0 appears to be4 a limiting and idealand unreal form. My copending applications Serial Numbers 86,741 and 117,515 are par-l ticularly useful in preparing catalytic surfaces for my invention.- Nickel peroxidtcatalyst as prepared therein appears to havean activity of near 1.7, cobalt peroxide anv activity somewhat above 1.5. My copending application Serial Number 86,741 also discloses the preparation of copper, silver, lead with respectively decreasing activities ranging from near 1.5 for copper down to near unity for lead. All these oxides are hydrated. I may use them all. My Serial Number 86,741 discloses the preparation and reactivation of black catalytic surfaces, winch are hydrated readily reducible oxides or peroxides. rILhe preferred step is anodic peroxidation in a low activity coefficient electrolyte in Whose anolyte hydroxyl is the predominant ion. These catalysts and their metals and the anodic peroxidation are extraordinarily Well adapted to sulphur sensitive motor fuel hydroning. The precipitated sulphides 'of these metals are black. Hydrated ferric oxide has a higher activity than magnetite.

The moderately reducible oxides such as mag- Infthe' stationary forrnY l nitrate of the-catalytic metal.

'deeper than the sulphide roasted surface and sulphided metal catalyst to the oxide little affects the area, vbut generally diminishes the depth and hence the catalyst concentration. The prior art of regenerating sulphided surfaces ordinarily roasting.

I prefer to carry the reactivation far beyond ordinary roasting, for instance to further oxidize at lower temperatures, thereby producing a darker and deeper surface layer. Such a treatment I have described in my copending applications, e. g., in Serial Number 117,515, the oxidizing reagent is aqueous. Or I may expose the roasted surfaces to the vapors of nitric acid at a liquid phase temperature of Ithe acid, below about the boiling point of the acid. When sulficient acid has been used to give the surface the characteristic color of the nitrate, I may gently roast at a lower temperature than that of the sulphide roasting-step to decompose most of the This surface is generally darker. The decomposed nitrate vapors may be recovered and reconverted to nitric acid, and used again. Other oxidizing or oxidizable reagents may be used, particularly aqueous reagents.

In general I may use `in my catalytic surfaces those elements or metals whose precipitated sulphides are black, particularly if they also readily form black oxide surfaces. This includes the noble metals, but their scarcity generally prevents their use.

The catalytic surface generally used comprises nickel or copper, which may be prepared in the many Ways known to the art. The catalytic surface may also c-omprise one or more accessory metallic elements, such as cobalt, chromium, molybdenum.A Of lesser total hydroning capacity, but more inclined to desulphurization as compared to hydrogenation is activated copper. Copper is able to open oxygen heterocycles, especially in the vapor phase. Nickel, the most active, is adjacent in atomic number to the next two most active, namely copper andcobalt, and

I prefer these three hydrogenating metals which together with their readily reducible oxygen compounds are essential to practical hydrofining accompanied 'by substantial hydrogenating. Iron,

particularly when promoted with nickel, may be used.

The reduction temperatures of the metallic oxides with hydrogen constitute an index to their activity and effective hydrofning range. When a plurality of catalytic components are mixed .,together, the reduction temperatures are generally lower than the arithmetic average, although under such circumstances the less active metal may not become fully reduced, which may often be advantageous.

In the vapor phase with an excess of hydrogen, unreduced catalyst may be in a process of reduction while hydrofining.

Deactivation tends to be selective on the most active centers, although my gradient operation .current example.

apparently minimizesl the effect. If oxides 'or' readilyreducible oxygen compounds such as the carbonate or formateare present during the deactivation, their gradual'reductlon constitutes a reserve source of such centers. The oxides themselves possess desulphurizing power, and the black hydrated oxides appear to possess hydrogenating power.

Advantage is taken of the partial sulpbiding and other deactivation of nickel and like catalyst to inhibit the complete hydrogenation of com- Pounds such as diolenes and aromatic compounds wlth oleflnic side chains, and to minimize hydrogen addition to non-cyclic mono oleconsists of no other chemical treatment than fines in the case of motor fuels and solvents. The copper and cobalt catalysts, particularly the copper, promote this type of hydrogenation without being deactivated. Apparently this is true of ylow pressure hydrogenations where the catalyst of the catalytic metal is preferably converted tol a sulphide. The oxygen compound may be reduced to the metal or a lower oxide concurrently with the hydrogenation and desulphurizing, particularly when the hydrogenation is substantial. The hydrogenatlon and the reduction, generally highly exothermic, appear to assist the desulphur izmg.

The following is a sample reaction when using catalytic surfaces comprising nickel on cracked motor fuel distillate as described in the counter- The surfaces function here both as a catalyst and reagent:

where R is mono or diolefinic and where n is an integer which may be varied and depending upon several factors such as the refractory nature of the distillate and the pressure of the treatment, and the catalyst activity. 3 is an example of a value for n. With similar vapors and pressures, diminished values of catalyst activity, fresh or partially deactivated, result in rapid decreases in the value of n.

Thus when operating the stationary form of my invention at constant pressure, the value of n, at first relatively high, progressively falls, and when the catalytic surfaces are nearly spent the value may even be negative, indicating dehydrogenation. Thus, in hydroning the vapors of motor fuel distillate, the hydrogenation decreases much more rapidly. than the desulphurization as the catalyst becomes spent when using constant pressure. By substantially increasing the pressures as shown in the stationary example, particularly when also decreasing the hydrogen exv cess, the ratio of hydrogenation to desulphurizal arianne4 to minimize the. heat requirements in excess of those for the cooler stages.

The amount of hydrogen needed for the hydroilning varies; yin general an excess is used, and in practice the lower the temperature, the greater this excess.

The following proportion is an example of K the excess of hydro en and differential variations or gradients there f, which may be used with motor fuel distillates:

` Minimum desirable volume H, GM

Volume hydrocarbon vapors 0.01 T--y where G is the Cu dish gum of the unhydronned distillate in mg. per 100 ml., and where T is the absolute Kelvin temperature, and where y is the fresh catalyst activity.

Indeed my invention may be operated without any added hydrogen or hydrogen excess during the hotter or warmer stage contacts when the catalyst is highly deactivated, particularly when relatively large quantities of labile sulphur cornpounds and relatively small quantities of dioleflnes and oleilnes are present. However it is preferable to have hydrogen present, the atom" of removed sulphur is best replaced by a'molecule of hydrogen.

Hydrogen may be generated during hydroflning and render it unnecessary to add other hydrogen. Relatively crude or impure hydrogens may be used in the practice of my invention, since the.

hydrogen is in a process of refinement concurrent with that of carbonaceousy vapors. In sulphur sensitive catalysis, the excess hydrogen undergoes continual purification. In sulphur immune catalysis, the hydrogen undergoes continual contarnination. Crude hydrogen may be puried independently by my invention, particularly with temperature gradients,

Stationary example In Fig. 2 is diagrammatically shown a vertical stationary catalyst form of the'invention.

Refractionated liquid motor fuel distillate is pumped by pump II through a pipe coil in a variable heat furnace I3, into a vaporizing tower I5. Here the distillate is vaporized and meets a regulated excess of hydrogen I1, preferably preheated. The regulation takes' place at the valve device I9. Heavy ends may be withdrawn from the vaporizing tower at 2| or 23. The vaporhydrogen mixture leaves I5 at outlet 25 fand passes into the top of the hydroflning chamber I0 at the inlet 21. The chamber I0 contains the catalyst. The chamber is supplied with open steam inlet 29 and steam outlet 3i. The hydrofined vapors plus any possible condensate then pass through exchanger I9, through condenser 20 into the receiver-separator 33. The bulk of the water of reduction is withdrawn at outlet 24. 'I'he residual moisture is separated from the hydroflned liquid in dehydrator 99. Gum inhibitingantioxidants in solution may be pumped by; proportionator I0 into the pump 38, where `they are mixed with hydroned motor fuel andl pumped to storage 4I. Meanwhile the excess hydrogen separated in 29 is returned to the tower I5 via recirculator 42 through exchangerV I8 in heat exchange with vapor-hydrogen mixture.

' As an example of how the stationary catalyst form of my invention may bepracticed, the li'ydroflning chamber I9 is filled with stationary unreduced nickel catalyst prepared as described in my copending application Serial Number 86,741. Steam is passed in at 29 while outlet 9i is partially open. When the temperature of the chamber hasreached 120 C. 29 and II are shut oif. Meanwhile a cross-cracked California motor fuel distillate may be pumped at a substantially constant rate through I9 into the vaporizing tower I5. The vapor along with 3 volumes of hydrogen at a temperature of C.

ntia'be passed into the hydrofining chamber I9 a The temperature of the vapor -hydrogen mixture may be steadily increased by increasing the heat in furnace I3 and in accordance with a schedule as indicated in Fig. 1 intermediate to curves l and 6, corresponding to a` parabolic exponent of about 2.7 and a catalyst activity of 1.7 in the fresh state. The unit time is about 30 hours corresponding to a total time of about 48 or 50 hours. The pressures may also be increased and the relative hydrogen volume and excess decreased according tothe following schedule. The changes may be stepwise or continuous:

Hours Temperature Hydrogen l Pressure C. Volume Atmospheres e isi 2.5 1.5

m 2 y 2 210 l. 8 3 i3 4s 1' io After this, the operation may be shut down and hydrogen alone passed for a while, then the kcatalyst may be steamed via inlet 29 and outlet 3|, and hydrocarbons recovered from the steam by condensation.

Results of the hydroflning on` the different samples:

BeIorehydro- Alter hydrolining` lining Sulphur percent (average) 0.76..; 0.13.

Color Oran Waterwhite. Doctor test Posit vom-. Negative. Sillcotungstic acid test..- ositive..- Negative.

` creases of pressure would result in an average sulphur content of below 0.09%. All samples in all these runs were doctor sweet, all water white up to about 240 C. at 1 atmosphere.

All samples represent a steady state, obtained without restriction on the output per weight of catalyst.

The hydrogen consumption in the 1 atmosphere runs was approxixnated at less than" 2 or 3 cubic-feet per gallon. v

Inspection of the cross-cracked California discountercurrent example In Fig. 3 is diagrammatically shown a vertical countercurrent form of my invention in detail. This may be operated strictly continuously,

v-30 and at atmospheric pressure, to produce a uniform stable product highly responsive to antii knock and antioxidant reagents.

, ltefractionated motor fuel vapor mixed-with hydrogen is fed into the vertical countercurrent 35 hydroning chamber I0 at the inlet I2. The

vapor mixture may enter as shown at 280 C. and as it passes upward may be cooled by passing cold or somewhat preheated hydrogen into the mixture through graduated openings in the 40 concentric pipe I4 running the length of chamber Il). The hydrond vapor mixture may leave the chamber I l at the outlet I6 near the top, any may then pass in heat exchange with the recirculating hydrogen. through the exchanger 45 I8, thence through. the condenser 20 into the separator 22. Any water may be drawn oif at the outet 24. The liquid hydroflned motor fuel is stripped of its dissolved hydrogen in the hydrogen stripping tower 26 with steam inlet 28,

o and outlet 30. Inlet 28 may be shut or throttled and a vacuum applied at outlet 80. The stripped liquid passes thence into receiver 82. Further water may be drawn off at outlet 24.' The hyfrom inlet 61. The air-sulphur dioxide mixture passes out at orice 65. l

The sulphur dioxide may be recovered, for instance as liquid sulphur dioxide or made into sulphuric acid. l'I'he sulphided catalytic surfaces are substantially converted into an oxide in 66, and pass outl at the bottom of 66 into the lock 60 to conveyor 62 and on into chambers 68 and 10, where the oxide surfaces are countercurrently further oxidized toA deeper and preferably black surfaces. The reactivated catalytic surfaces pass out of the chamber through the bottom lock 60 into conveyor 62 and into the top y lock 60 of the hydroining chamber I0, to comdroilned `liquid` passes'l thence through the hy- Il droilned liquid outlet 34` through the dehydrator 36 into the pump v88 where it may be mixed with agum inhibiting antioxidant in solution from the inhibitor poporiionator an. The inhibited hydroilned liquid may then pass to finished stor- N age 4I.

86 motor fuel fracticnator 46 at inlet 48. New hydrogen, fromthe hydrogen producer not shown is also passed into the reboiler section 44 at inlet x The hydrogen-refractionated vapor mixture passes from vthe reboiler section 44 throughoutlet I2 and on into the hydroning chamber III..

' Meanwhile the hot spent catalytic surfaces pass at constant intervals into the lock 80 and thence vla the catalyst conveyor 62 into the countercurrent steaming chamber 64 .where thehot catalyst k'Il downward meets upiiowing steam. enterplete the'cycle. Where substantial sulphur is removed from the distillate, the cycle or turnover of the catalytic surfaces may require 1 to 3 days, ,Usually cracked distillate passes from furnace-coils to a soaking drum to the primary fractionator. The motor fuel distillate therefrom usually contains excessive quantities of propane, butane, isobutane and butylene and isobutylene. These are separated as overhead through 41 in the refractionator 46. The debutanized distillate may then be reboiled, mixed with hydrogen in 44, and passed out/via 52 and I2 into the hydroiining chamber I0 just above the lock 60. I prefer to debutanize or "stabilize in the refractionator somewhat more deeply than usual since desulphurizing and/or Two or more pipes may be substituted for pipe n hydrogenating lowers the boiling point of these I4 to allow the introduction of cooling hydrogen at two or more temperatures. The chamber I0 contains devices 39 for distributing the catalystv and alleviating the head pressure thereof.

Twelve stages. of different .temperatures as y shown divide the hydrofining chamber I0. One

to four more such stages may be inserted at the bottom to extend the temperatures up to 350 C. or up to the temperature at which substantial pyrolysis occurs, particularly if the additional heat is available. Or one or two stages might be eliminated if insuicient heat is at hand. The

more active and hydrogenating catalytic surfaces v such as those which comprise an element selected from the group which consists of copper, nickel and cobalt, or from the group which consists of nickel and copper.

The countercurrent form of my invention may be practiced for example using the same distillate as in the stationary form.

The catalytic surfaces may be prepared by immersing small lumps of an abrasive and refractory form of alumina in molten nickel nitrate hexahydrate, draining, drying, and gently roasting the impregnated lumps to decompose most of the nitrate. The hydroflning chamber I0 may be lilled with this material and warmed with open steam or hydrogen, 'I'he California cracked distillate in substantially constant feed may then be mixed with 3 volumes of hydrogen in the reboiler section and the vapor mixture fed into I at inlet I2 at a temperature of about 130 C; The mixture is cooled to about 110 o C. with hydrogen before it emerges fromv IUI at outlet IB. The temperatures in lil arel gradually raisedto the schedule shown-to the right of the chamber l0 in Fig. 3. The period should require at least a day and preferably three days. During that day or so, fresh catalyst is fed in through the top lock 60 of chamber I0 at an average of about onehalf the usual rate once, the operation is established. The catalyst feed should start from about nothing and progressively increase to the full feed as the temperatures reach the 280 C.-coo1e'dto-150 C. schedule as shown. Concurrent with these increases of temperature and catalyst feed during that day or so, the volume of hydrogen fed into 44 is gradually decreased to about onehalf volumes or less, when it may remain constant.

After the first two days or so the operation lis uniform and as strictly continuous as desired' barring mechanical disturbance. A relatively large volume of cooling hydrogen is added in the cooler stages relative to that added in the intermediate stages. Once established, the total cycle including reactivation may be completed in about twodays. The time for fresh catalyst at thev top of chamber I0 to reach the bottom lock 60 of the chamber is several hours less. The time varies principally with the amount of sulphur removed. Where Sr% is the percentage of sulphur removed by weight of the distillate, the

maximum total cycle including reactivation appears to be between 1Sr%1/:i and y2Sr%1/3 days for either the countercurrent or stationary form of the invention. The resulting countercurrent hydroflned product at one atmosphere may also ,equal the extent of the hydrofining by the stationary form under ascending gradients of temperature and pressure and a descending gradient of hydrogen excess. When using the same distillate, the same catalytic components and the same means of activation, the two forms compared over extended practice may be expected to yield nearly the same product.

Reactivation of the spent catalytic surfaces from the bottom lock 60 of chamber i0 may be steamed and roasted as in the description of Fig. 3. The further oxidizing may be carried out by the nitric acid vapor treatment and gentle roasting previously described. Or the surfaces` mayv be further oxidized by other means, particularly one of those previously described. y

The countercurrent form of my invention may be practiced in a horizontal or slightly inclined in each stage so that relatively equal amounts'of lwdroflning occur in each stage. The operation .is constantly focused on producing a uniformproduct whatever the condition of the catalyst. In the countercurrent form however the warmest stages are devoted almost entirely to desulphurizing, while .hydrogenating is usuallythe predominant hydrofining reaction in the coldest stages. The ratio of hydrogenation to desul- .phurization increases with the cooling and hence the comparative ltotal hydroiining in each stage cannot be directly compared with that in the other stages. The` comparison may be made indirectly by comparing with similar stationary results. For example samples may be withdrawn at each of the twelve stages in Fig. 3, and comparing'theln with the twelve successive samples (one every 4 hours say) from a full stationary run at the same pressure, but using the optimum temperatures and hydrogen excesses determined from a previous run at optimum differentially varied temperatures, hydrogen excesses, and pressures.

Ordinary surface transfer cooling may be used stance using the static-nary form with relatively narrow time gradients and a relatively wide space thermal gradient. This unusual space gradient is due tothe exothermal heat which may be controlled with narrow reaction chambers, e. g., 4 cm. (ll/finches) diameter cylinders surrounded by a heat exchange fluid. Hydrogen'cooling may also be used for this control. The rate of change in the time gradients as well as the ranges thereof are small relative to the desulphurizing type of hydroning. The reaction is preferably spread over several chambers in series, Whereas one single chamber is usually sufficient in the desulphurizing type of hydrofining. The catalyst activity is preferably in excess of about f1.5. The hydrogen excess is regulated preferably so that the vapor mixture is near saturation during hydroning. Likewise my method may be applied to the conversion of watergas to motor fuel distillate, particularly with the promoted catalysts described in my copending application Serial Number 117,515, and with small diameter reaction tubes. My invention may be likewise applied to the conversion of isooctene, isononene,

"' isodecene, to isooctane, isononane, is'odecane respectively.

Straight run or cracked petroleumk distillate 'may be separated into fractions high in sulphur, and fractions high in gum but low in sulphur. These may be separately hydroned and reblended wholly or partially.

Besides natural and synthetic petroleum distillates, the light distillates or gases from other sources, such as those resulting from the pyrolysis of shale oil, primary tars and Bergenized-oils from coal are refined and even converted to new products by my hydroiining. Such distillates are \apt to contain considerable quantitiesof organic bases and acids, which are best Washed out with acid and alkali solutions respectively, before being subjectedjto my hydrofning. These distillates after the washes above may still contain heterocyclic compounds of oxygen in addition to those of sulphur. Copper hydroiining especially in the vapor phase will convert the oxygen heterobonaceous vapors, particularly those containing oxygen, mayybe subjected to my lhydrofining method.

What I claim is: 1' 1. A method of continuously hydrofining carbonaceous vapors, which comprises continuously contacting the vapor and an excess of hydrogen in a series of time stages with a solid sulphur sensitive catalytic surface containing a catalytic metal whose precipitated sulphide is-black, at a plurality of temperatures above about 75 C. but below the temperature at which `substantial pyrolysis occurs with said vapor, and adjusting the temperature and hydrogen excess of each of the time stages so that relatively equal amounts of hydrofining occur in each of said stages, said plurality of temperatures consisting substantially oi' an ascending time gradient of temperature, the rise of temperatureoccurring as the catalytic surface becomes progressively. spent, the difference between the extremes of said gradient being between about C. and 200 C., while Amaintaining the pressure of each stage between about l and 100 atmospheres.

2. A method as described in claim 1, then further hydroilning the carbonaceous compound or compounds in additional-but fewer stages, and with decreasingly less amounts of hydrofining in said additional stages.

3. A method of continuously hydrofining carbonaceous vapors, which comprisesy contacting the vapor of motor fuel distillateand an excess of hydrogen in a series of similar stages with a solid sulphur sensitive catalytic surface containing,a catalytic metal whose precipitated sulphide is black, the temperature in each stage being above about 75 C., but below the temperature at which substantial pyrolysis occurs with said vapor, and adjusting the temperature and hydrogen excess of each of the series of similar stages so that relatively equal amounts of hydrofining occur in each ofv said stages, while maintaining the pressure oi'K each stage between about 1 and 20 atmospheres, and a time of contact at least until the distillate is doctor sweet but insufcient to completely hydroilne, and after condensing the hydroiined distillate adding a small portion of a gum inhibiting antioxidant suilicient to yinhibit formation oi.' gum. f

4. A method of continuously hydrofining carbonaceous' vapors, which comprises mixing the vapor of cracked and refractionated motor' i'uelI distillate from petroleum together with an excess of hydrogen and in a series of similar stages y contacting the mixture with a readily reactivatable solid sulphur sensitive catalytic surface containing va catalytic metal whose precipitated sulphide is black, at a plurality of temperatures above about 75 C. but below the temperature at whichsubstantial pyrolysis occurs with said distillate, and adjusting the temperature and hydrogen excess of each of said similar stages so that relatively equal amounts of hydrofining occur in each of said stages, said plurality of temperatures consisting substantially of an ascending time gradient of temperature, the difference between the extremes of said gradient being between about j 20 C. and 200 C., while maintaining the pressure of each stage between about 1 and 20 atmospheres and a time of contact at least until the distillate is doctor sweet, then Vcondensing the hydrocarbons and separating the excess hydrogen to produce without further chemical treatment or separations a refined motor fuel which is highly responsive to anysubseque'nt addition of antioxidant or antiknock reagents.

5. A method of continuously hydrofining carbonaceous vapors, which comprises contacting the vapor of a motor fuel or like distillate and an excess of hydrogen in a series oi similar stages with Aa 'solid sulphur sensitive catalytic surface containing a catalytic metal whose precipitated sulphideris black, at a plurality of temperatures above about 75 C. but below the temperature at which substantial pyrolysis occurs with said distillate, and adjusting the temperature and-hydrogen excess of each of the similar stages so that relatively equal amounts oi' hydrofining occur in each of said stages, said plurality of temperatures consisting substantially of an ascending time gradient of'temperature, the rise of temperature occurring' as the catalytic vsurface becomes progressively spent, said rise being less than 200 C.

6. A method of continuously hydrofining car-v bonaceous vapors,l which comprises contacting the vapor of a motor fuel or like distillate and an excess of hydrogen in a' series of similar stages with a solid sulphur sensitive catalytic surface containing a catalytic metal whose precipitated sulphide is black at a plurality of temperatures above about 75 C. but below the temperature at which substantial pyrolysis occurs with said distillate, and adjusting the temperature and hydrogen excess of each of the similar stagesv so that relatively equal amounts of hydrofining occur in each of said stages, said plurality of temperatures consisting substantially of an ascending timefgradient of temperature, the rise of temperature occurring as the catalytic surface becomes progressively spent, said rise being less than 200 C. in extent, while maintaining the pressure of each stage between about l and 20 atmospheres, and a time of contact at least until the distillate is doctor sweet but insuillcient to completely hydrone, then reactivating the catalytic surfacepby a process which comprises roasting to substantially convert the metal sulphide to oxide, and afterwards treating the roasted catalyst with nitric abid vapors, followed by gentle roasting at a temperature lower than that of the sulphide roasting step to decompose most of the nitrate of the catalytic metal, and then recycling said reactivated catalytic surface to the initial and lowest temperature hydrofining stage.

7. A method of continuously hydroning carbonaceous vapors, which comprises contacting the vapors of motor fuel or like distillate andan excess of hydrogen in a seriesof stages with a solid sulphur sensitive catalytic surface containing a catalytic metal whose precipitated sulphide isblack, the hydrogen excess being high and the temperatures being relatively low but above about '75 C. in the stages when the catalytic surface is in a freshly activated condition, and progressively decreasing the hydrogen excess and increasing the temperature to an upper limit between about 250 C. and the temperature at which substantial pyrolysis occurs with said vapors as the catalyst activity decreases during hydronning, the total rise in temperature being between about 100 C. and 200 C., and maintaining a pressure in each stage between about 1 and 20 atmospheresand a time of contact at least until the distillate is doctor sweet but in' suicient to completelylhydrotlne, said freshly activated catalytic surface comprising a readily reducible oxygen compound of a sulphur sensitive hydrogenating metal, said catalyticy surface being converted to the sulphide ci said hydrogenating metal during hydroilning.

8. A method as described in claim 7 in which the temperatures are raised less rapidly in] the intermediate than in the extreme stages.

9. A method o! continuously hydroi'ining the vapor of motor fuel or like distillate, which comprises the countercurrent contact oi the vapor oi distillate with solid sulphur sensitive catalytic surfaces comprising nickel, at a plurality of temperatures above about 75 C. but below the temperatures at which substantial pyrolysis occurs with said vapor, and progressively adding hydrogen in amounts over and above the chemical requirement to cool the vapor or vapor mixture as it contacts progressively fresher catalyst, the total cooling being between 100 and 200 C., while maintaining a substantially constant pressure between about 1. and 20 atmospheres throughout the contact, and a time of contact at least. until the distillate is doctor sweet.

1o. A method as described in claim 9 in which the ilow of catalyst is downward, the flow of vapors upward, and in which the catalytic surfaces in the cooler and fresher catalyst stages comprise an oxgen compound of nickel in the process of partial reduction concurrent with the hydroilning.

11. A method of continuously hydroning' carbonaceous` vapors, which comprises contacting the vapors and an excess of hydrogen in a series of similar stages' with a solid sulphur sensitive.A catalytic surface containing a catalytic metal whose precipitated sulphide is black, and decreasing the hydrogen excess and increasing the temperature in the time stages of said series as the catalytic surface becomes progressively spent during hydroiining, said temperature increase not to exceed 200 C., the temperatures in each stage being above about 75 C. but below the temperature at which lsubstantialpyrolysis occurs with said vapors, while maintaining the pressure of each stage. between about 1 and 100 atmospheres.

MARION H. GWYNN.

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