US3125510A

US3125510A - Treatment of hydrocarbon fractions

Info

Publication number: US3125510A
Authority: US
Priority date: 1960-10-28
Publication date: 1964-03-17
Anticipated expiration: 1981-03-17
Also published as: BE609624A; US3125511A; GB943237A; NL270706A; BE609623A; NL270707A

Description

3 125 510 TREATMENT or HrnnocAnnoN FRACTIONS Kenneth Tupman and Peter Thomas White, Snnhury-on- Thames, England, assignors to The British Petroleum Company Limited, London, England, a British joint-.

stock corporation No Draw'mg. Filed Oct. 24, 1961, Ser. No. 147,182 Claims priority, application Great Britain Oct. 28, 1960 10 Claims. (Cl. 208264) This invention relates to the treatment of hydrocarbon fractions, particularly petroleum fractions, boiling above 150 C., and the principal object of the invention is to provide a process by means of which the cloud point, pour point or freezing point of such fractions may be lowered.

According to the present invention a hydrocarbon fraction boiling above 150 C. is contacted with a catalyst comprising a platinum group metal on a refractory oxide support in the presence of hydrogen and added halogen at a temperature of at least 600 F. and a pressure of at least 100' p.s.i.g., the temperature and space velocity used being correlated to give a product boiling above 150 C. having a pour point at least 5 F. lower than the pour point of the feedstock.

It has been found that the presence of added halogen gives a markedly greater reduction in pour point compared with a similar operation without the halogen. In the case of the treatment of a heavy gas oil feedstock having a pour point of 50 F. with a platinum-aluminahalogen catalyst for example, the presence of an added halogen compound gave a reduction in pour point of 75 F. compared with a reduction of F. for a similar operation without the halogen compound. The reduction of pour point of 75 F. was achieved with a yield of product (boiling above 150 C.) of 80% wt.

The term fraction as used in this specification includes both fractions which are distillable at normal or reduced pressure, for example gas oils and waxy distillates, and also residues and portions thereof, for example deasphalted residues. Particularly suitable fractions for use as feedstocks are distillate fractions boiling within the range 150 to 450 C. and more particularly within the range 250 to 450 C.

It has been found that it is not necessary to desulphurise the feedstock prior to submitting it to the pour point reduction process, although such a preliminary desulphurisation may be given if desired. When operating with a sulphur-containing feedstock (-for example one with more than 0.1% Wt. of sulphur) the process will normally effect considerable desulphurisation simultaneously with the lowering of the cloud point, pour point or freezing point. It has also been found that the process can be operated in the presence of considerable quantities of hydrogen sulphide, so that, for example, the process can be operated on the total effluent of a previous hydrocatalytic desulphurisation process.

If desired, a part only of a particular distillate may be treated by the process according to the invention and the resulting product blended with the untreated portion of the distillate to give a final product of reduced pour point.

The added halogen may be added to the reaction zone in any convenient manner, for example by injecting it directly into the reaction zone, by adding it to the hydrogen-containing gas used, or, preferably, by adding it to the feedstock. Examples of suitable halogens are fluorine,

3,125,510 Patented Mar. 17, 1964 chlorine, and bromine, the former being preferred because corrosion difliculties are minimised. The halogen may be added as such, or as a halogen compound which is decomposable to halogen under the reaction conditions. Preferred halogen compounds are those having halogen together with one or more of the elements carbon, hydrogen or oxygen, for example hydrogen halides and halogen derivatives of aliphatic hydrocarbons having from 1 to 4 carbon atoms. The halogen is preferably added in an amount from 0.001 to 1% wt. by weight of feedstock.

The platinum group metal content of the catalyst may be within the range 0.01 to 5% wt., preferably 0.11.0% wt. The preferred platinum group metals are platinum and palladium. The refractory oxide support may be one or more of the oxides of metals of group II, III and IV of the periodic table. Preferably it contains a major proportion of alumina and it may also contain a minor proportion of one or more of the other oxides of metals of groups II, III and IV of the periodic table. Preferably the amount of the group II, III or IV metal oxides is from 5-25% wt. of the support. Examples of suitable supports include alumina, silica/ alumina, titania/ alumina, zirconia/alumina and beryllia/ alumina. The support material may also contain a minor proportion of one or more compounds (including oxides) of non-metallic elements in groups III, IV and V for example boron or phosphorus, which may if desired be combined or mixed with any of the metal oxides of groups II, III and IV. Preferably the amount of the compounds of the non-metallic elements is from 5 to 25% Wt. of the support.

The catalyst may be halogen free or it may contain less than 1% wt. of halogen as disclosed in the complete specification of cognate UK. patent applications Nos. 28,788/ 60, 37,123/ 60 and 5,774/61, or it may contain at least 1% Wt. of halogen as disclosed in the complete specification of UK. patent application No. 37,126/60, in addition to the halogen present in the reaction zone by the addition of halogen. The catalyst may be employed as a fixed bed, a moving bed, or in the fluidised state.

An essential requirement to obtain pour point reduction with any given catalyst and operating conditions employed is a correlation of temperature and space velocity. In general the higher the temperature, the higher the space velocity that can be employed, the upper limit of temperature, at any given space velocity, being determined by the amount of cracking occurring. The feedstock used, the activity of the catalyst used and the reduction of pour point required should also be taken into account when selecting the process conditions. When treating the heavier feedstocks, for example, the operating conditions may be more severe (i.e. conditions of higher temperature and/or lower space velocity) than when treating lighter feedstocks.

When using a more active catalyst or when using a greater quantity of added halogen, less severe conditions may be used, an equivalent reduction in pour point being obtainable at a lower temperature and/or higher space velocity.

Preferably the temperature is below that at which substantial cracking occurs, and, for the purposes of the present specification substantial cracking is understood to occur when more than 20% wt. of the feedstock is converted to material boiling below C. Prefen ably not more than 15% wt. of the feedstock is so converted. In practice the temperature will not normally exceed 950 F. and is preferably at least 700 F. Similarly in practice the space velocity will not normally be less than 0.1 v./v./hr. and more particularly not less than 0.5 v./v./hr. Preferably it does not exceed 8 v./

used and inspection data on the feed and product were as follows:

Operating Conditions o ul 'cee v /hr and m re part1c arly it does not ex d v /v Catalyst co Mo/alumma hr. The pressure may be from 100 to 1500 p.s.1.g. and 5 Prewure p Sig 1000 the hydrogen:hydrocarbon mole ratio from 1:1 to 20:1. Temppratu'rg 730 The process may be operated with or without a net S pace velocity v./v./hr 2.0 hydrogen consumption. A net hydrogen consumption Gas recycle rate s.c.f./b 1000 is generally favoured by increase in pressure and for any given temperature and space velocity the pressure at R ul which the hydrogen consumption and hydrogen production are in balance is known as the equilibrium pres- Feed Product sure. It is generally preferred to operate at or above this pressure because this results in an increase in the onspecific Gravity 0 13/600 F M76 0850 stream time before catalyst regeneration or replacement 15 i t is necessary. Another advantage of this type of oper- 051j'g555ggg5555; jjjj 52 atlon is, for example, that when processing feedstocks 3g? g gg g such as gas oils for the production of diesel oils, reducll fffi? f 1:: I: 395 tion of the diesel index is minimised or avoided. The lg u ggg h 8g principal advantage of operating below the equilibrium 20 clogd f pjj""""' II: I: Q pressure is that a reduction in the specific gravity of the Your Point, F 50 50 distillate is minimised or avoided. P the FY0965S 115mg a d f 0f P y The hydrofined product was then processed over a is carried out in the normal manner, whicn 13 to increase platinum Catalyst to reduce its pour point The Catalyst the temperature gradually as the run continues in order composition to maintain the quality of the product at the desired level. Percent wt The process of the present invention will normally Platinum 0.75 lower all the three points specified, viz. cloud point, pour Fluorine 0.35 point and freezing point. Which point is taken as the 9 Chlorine 0.35 criterion for any particular operation will depend on the Al ina Balance feedstock used and the use to which the product is to be Four runs were carried out In the first run them was P The freezlng P 1S normally only of lmponance no addition of a halogen compound to the reaction zone;

. g With the lower bolllng f 1n the second carbon tetrachloride was added to the feed- In c pendlng PP a 3/ 61 a procstock in an amount to give 0.1% wt. of chlorine by weight ess for the treatment of hydrocarbon fractions boiling of feedstock; in the third the amount of carbon tetraabove 150 C. to reduce their cloud point, pour point, or chloride was sufficient to give 0.5% wt. chlorine, and in freezing point is described, in which the fractions are the fourth tertiary butyl chloride was added in an amount first treated to reduce content of aromatic hydrocarbons, g Wt. lorm or nitrogen compounds or both. go After the processing the product was stabilised to re- Such a process may if desired, be Combined with the move a small proportlon of material boning below 150 0 process of the present invention, as may the processes FE gave a gas 9f the requlred flash Pomt (1 50 disclosed in the copending applications referred to earlier, 5913 g used and results Obtained are viz. in the complete specification of cognate UK. appliglven a e e TABLE 1 Pressure, p.s.i.g 500 500 500 500 Space Velocity, v./v./hr 1.0 1.0 1.0 1.0 Hydrogen Rate (once through), s.c.f./b. 5000 5000 5000 5000 Feedstock DcsulphurisedHcavy Dcsulphurised Heavy Gas Desulphuriscd Heavy Gas Desulphuriscd Heav Ga Gas Oil Oil containing 0.1% Wt. Oil containing 0.5% wt. Oilcontaining0.5%wt.01 01 (added as carbon tctra- C1 (added as carbon tetra- (added as tertiary butyl chloride) chloride) chloride) Operating Temperature,

F 775 800 825 775 800 825 775 800 825 775 800 825 Product (Unstabllised):

Cloud Point, F 54 50 44 42 26 12 28 16 12 24 s -4 Pour Point, F 50 40 3o 20 10 25 15 -15 20 20 4.5

Feed Feed Feed Feed Product (Boiling 150 0.):

Cloud Point, F 60 66 60 60 26 12 -s Pour Point, F 50 50 20 -5 -25 Yield (based on feed),

Percent wt 100 92 100 100 100 90 cation Nos. 28,788/60, 37,123/60 and 5,774/61 and in the complete specification of UK. application No. 37,126/ 60.

The invention is illustrated by the following examples.

EXAMPLE 1 A heavy gas oil was hydrocatalytically desulphurised over a catalyst of 2.4% wt. cobalt oxide and 14.3% wt.

The results show the very much greater reduction in pour point obtainable when operating in the presence of a halogen compound.

EXAMPLE 2 A comparison of the effects of fluorides, chlorides and bromides on the pour point reduction of desulphurised heavy gas oil was carried out using the same catalyst,

molybdenum oxide on alumina. The process conditions 7 feedstock and feedstock preparation as those used in Ex- O ample 1. Three runs Were carried out, in the first tertiary butyl chloride was added to the feedstock in an amount to give 0.1 percent weight chlorine by weight of feedstock; in the second tertiary butyl bromide was added to the 6 is converted to material boiling below 150 C. and said selected space velocity being at least 0.01 v./v./hr. but not higher than 8.0 v./v./hr. at which, at said selected temperature, not more than 20% wt. of the feedstock is feedstock to give 0.1 percent of bromine; in the third converted to material boiling below 150 C.; maintaining tertiary butyl fluoride was added to the feedstock to give a selected pressure in said zone in the range 1001 500 0.1 percent weight fluorine. p.s.i.g.a., said selected temperature and said selected space The process conditions used and results obtained were velocity being correlated to reduce the pour point of the as follows: feedstock such that the pour point of the material of the Pressure, p.s.i.g 500 500 500 500 Space velocity, v./v./hr. 1.0 1.0 1.0 1.0

Hydrogen rate through), s.c.f./b Feedstock (once 5,000 Desulphurised Heavy Gas Oil 5,000 Desulphurised Heavy Gas Oil containing 0.1 percent wt. 01 (added as 5,000 Desulphurised Heavy Gas Oil containing 0.1 percent wt. F (added as tertiary 5,000 Desulphuriscd Heavy Gas Oil containing 0.1 percent wt. Br (added as tertiary butyl chloride) tertiary butyl bromide) butyl fluoride) Operating Temperature, F 775 800 8 5 775 800 825 775 800 825 775 800 825 Feed Product Data:

Cloud Point, F 60 54 50 44 40 14 48 38 18 48 42 20 Pour Point, F 50 50 45 40 15 5 30 5 45 40 5 EXAMPLE 3 treated distillate fraction boiling above 150 C. is at least The same feedstock, feedstock preparation and catalyst as that of Example 1 were used to study the effect of changes in process variables on the pour point reduction of desulphurised heavy gas oil containing carbon tetrachloride in an amount to give 0.1 percent weight chlorine by weight of feedstock.

The process conditions used and results obtained were as follows:

Hours on Stream 10-12 34-36 84-86 100-102 116-118 140-142 Operating Conditions:

Feedstock Desulphurised Heavy Gas Oil Containing 0.1% wt. 01 Catalyst Pt/Alumina Reactor Pressure p 750 750 750 750 750 750 Reactor temperature, F 775 775 825 825 675 7 5 Space velocity, v./v./hr, 1.0 2. 5 1. 0 2. 5 1.0 2. 5 Gas recycle rate, s.c.f./b 10,000 10,000 10, 000 10, 000 10, 000 10,000

Feed

Product (150 0.):

Yield, percent wt 90. 2 94. 9 86. 6 93. 0 97. 7 97.6 Cloud Point, F 60 28 46 6 36 58 60 Four Point, F 20 40 15 30 50 50 This example illustrates the necessity of correlating the temperature and space velocity to give a reduction in pour point. At 675 F. and 1 v./v./hr., and 725 and 2.5 v./v./hr., the temperature is too low, at the space velocity used, to give pour point reduction. However, if the temperature is raised to 775, pour point reduction is obtained at both space velocities, being greater at the lower space velocity. Raising the temperature to 825 F. further reduces the pour point.

We claim:

1. A process for the treatment of distillate petroleum fractions boiling within the range 150450 C. to lower the pour point at least 5 F. without material reduction in the specific gravity and diesel index of said distillate fractions, comprising contacting the distillate fraction as feedstock in a treating zone and in the presence of hydrogen and of halogen added to the treating zone in an amount from about 0.001 to 1% by weight of feedstock with a catalyst comprising a platinum group metal on a refractory oxide support, the hydrogen to hydrocarbon mole ratio being from 1 to 1 to 20 to 1; maintaining a selected temperature and a selected space velocity in said zone, said selected temperature in said zone being maintained at least at 700 F. but not higher than about 950 F. and being a temperature at which, at said selected space velocity, not more than 20% wt. of the feedstock 5. A process as claimed in claim 1 wherein the halogen is added in the form of a compound of halogen in which halogen is combined with at least one of the elements carbon, hydrogen and oxygen.

6. A process as claimed in claim 1 wherein the catalyst contains from 0.01 to 5.0% wt. of the platinum group metal.

7. A process as claimed in claim 1 wherein the platinum group metal is platinum.

8. A process as claimed in claim 1 wherein the space velocity is at least 0.5 v./v./ hr.

9. A process as claimed in claim 1 wherein the space velocity does not exceed 5 v./v./hr.

10. A process as claimed in claim 1 wherein the pressure is from to 1500 p.s.i.g., and the hydrogenzhydrocarbon mole ratio is from 1:1 to 20:1.

References Cited in the file of this patent UNITED STATES PATENTS 2,793,984 Northcutt et al. May 28, 1957 2,885,352 Ciapetta et al. May 5, 1959 2,888,397 Burton et a1. May 26, 1959 2,890,167 Haensel June 9, 1959 2,965,564 Kirshenbaum et al Dec. 20, 1960 3,085,971 Mooi et a1 Apr. 16, 1963 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3 125 510 March I7 1964 Kenneth Tupman et al., It is hereby certified that error appears in the above numbered patent req'liring correction and that the said Letters Patent should read as corrected below.

Column 3 line 35, for "No, 8238/61" read No, 8248/61 Signed and sealed this 8th day of September 1964.,

SEA L) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner of Patents

Claims

1. A PROCESS FOR THE TREATMENT OF DISTILLATE PETROLEUM FRACTIONS BOILING WITHIN THE RANGE 150-450*C. TO LOWER THE POUR POINT AT LEAST 5*F. WITHOUT MATERIAL REDUCTION IN THE SPECIFIC GRAVITY AND DIESEL INDEX OF SAID DISTILLATE FRACTIONS, COMPRISING CONTACTING THE DISTILLATE FRACTION AS FEEDSTOCK IN A TREATING ZONE AND IN THE PRESENCE OF HYDROGEN AND OF HALOGEN ADDED TO THE TREATING ZONE IN AN AMOUNT FROM ABOUT 0.001 TO 1% BY WEIGHT OF FEEDSTOCK WITH A CATALYST COMPRISING A PLATINUM GROUP METAL ON A REFRACTORY OXIDE SUPPORT, THE HYDROGEN TO HYDROCARBON MOLE RATIO BEING FROM 1 TO 1 TO 20 TO 1; MAINTAINING A SELECTED TEMPERATURE AND A SELECTED SPACE VELOCITY IN SAID ZONE, SAID SELECTED TEMPERATURE IN SAID ZONE BEING MAINTAINED AT LEAST AT 700*F. BUT NOT HIGHER THAN ABOUT 950*F. AND BEING A TEMPERATURE AT WHICH, AT SAID SELECTED SPACE VELOCITY, NOT MORE THAN 20% WT. OF THE FEEDSTOCK IS CONVERTED TO MATERIAL BOILING BELOW 150*C. AND SAID SELECTED SPACE VELOCITY BEING AT LEAST 0.01 V./V./HR. BUT NOT HIGHER THAN 9,0 V./V./HR. AT WHICH, AT SAID SELECTED TEMPERATURE, NOT MORE THAN 20% WT. OF THE FEEDSTOCK IS CONVERTED TO MATERIAL BOILING BELOW 150*C.; MAINTAINING A SELECTED PRESSURE IN SAID ZONE IN THE RANGE 100-1500 P.S.I.G.A., SAID SELECTED TEMPERATURE AND SAID SELECTED SPACE VELOCITY BEING CORRELATED TO REDUCE THE POUR POINT OF THE FEEDSTOCK SUCH THAT THE POUR POINT OF THE MATERIAL OF THE TREATED DISTILLATE FRACTION BOILING ABOVE 150*C. IS AT LEAST 5*F. LOWER THAN THE POUR POINT OF THE FEEDSTOCK, AND RECOVERING THE TREATED DISTILLATE FRACTION.