US3824183A - Acid number reduction of hydrocarbon fractions using a solid catalyst and nh3 - Google Patents

Abstract

THE ACID NUMBER OF A HYDROCARBON FRACTION IS REDUCED BY CONTACTING THE HYDROCARBON FRACTION AND A NITROGEN CONTAINING COMPOUND SUCH AS AMMONIA WITH A SOLID CAT-

ALYST HAVING A SURFACE AREA GREATER THAN 15 M.2/G., SUCH AS TITANIUM OXIDE ON ALUMINA.

Description

July 16, 1974 s, w U ETAL 3,824,183

ACID NUMBER REDUCLION 0F HYDROCARBON FRACTIONS USING A SOLID CATALYST AND NR Filed July 5, 1973 NH3 LIGHT PRODUCTS 511 I 22 DISTILLATE FUEL OIL N HEATER v DISTILLATE REACTOR FUEL on. Io

FLASH 26 CHAMBER HEAVY PRODUCTS US. Cl. 208-263 17 Claims ABSTRACT OF THE DISCLOSURE The acid number of a hydrocarbon fraction is reduced by contacting the hydrocarbon fraction and a nitrogen containing compound such as ammonia with a solid catalyst having a surface area greater than 15 m. /g., such as titanium oxide on alumina.

This invention relates to a process for reducing the acid number of hydrocarbon fractions, especially distillate petroleum oils. In particular this invention relates to the use of a solid catalyst in a fixed-bed type process for reducing the acid number of distillate petroleum oils in the presence of compounds like NH It is well known in the petroleum hydrocarbon art that carboxylic acids present in distillate fuels cause considerable problems in the transportation and storage of these oils. For example, the acid number specification of No. 2 fuel oils is less than 0.1. By an acid number is meant an acid number determined by ASTM Test No. D974. The fuel oils with higher acid numbers cause unwanted corrosion problems in that the acids attack copper and zinc in the fuel handling systems. In addition, the leached metals then present in the fuel oils tend to reduce the fuel stability and to cause deposit formation on injectors, flow controls and other critical parts of the operating mechan1sms.

Previously, the acid number of distillate fuel oils has been reduced by the treatment of these fuel oils with caustic such as sodium hydroxide. This particular method of acid number reduction, however, is fraught with its own problems, namely the formation of foam with the consequent loss of oil and the formation of undesired alkali metal salts such as naphthanates. The alkali naphthenates in turn can decompose to naphthenic acid and caustic upon contact with slightly acidic water. Because of pollution regulations, the naphthenic acids must be disposed of at an undesirably high cost. A mild hydrogenation treatment can also be employed to reduce the acid content of distillate fuel oils, but this process suffers from the high cost of operation. An improved process has now been discovered which tends to overcome many of the difficulties of the prior art processes.

The use of ammonia to convert organic esters and acids in petroleum fractions to nitriles is taught by Franklin M. Watkins in US. Pat. 2,301,281 issued on Nov. 17, 1942. Watkins teaches this reaction occurs thermally at temperatures from 500 F. to 730 F. (260 C. to 387 0.). The use of metallic oxides and salts having dehydrating characteristics will, according to Watkins, accelerate the conversion of acids and esters to nitriles. Watkins process is carried out in a closed reaction vessel and the only catalyst employed or mentioned by Watkins is levigated alumina. Despite the high temperature of operation, extended periods of time were required to obtain even a partial reduction of acid number. Thus, in Table I, Watkins shows that even after five hours of treatment, the acid number was still 0.4 despite the presence of the catalyst. Even after 11 hours of treatment, the product acid number was not below 0.1 even with a catalyst. Such United States Patent a high temperature, long contact time process is unacceptable for commercial operation.

A process has now been discovered which overcomes the disadvantages of the prior art and provides for the reduction of the acid number of a hydrocarbon fraction to a level below 0.1 by ASTM test D974, usually below 0.03 in short contact times of less than one hour, usually less than 30 minutes.

In accordance with the invention, a petroleum fraction having an acid number greater than 0.1 is contacted together with a nitrogen containing compound having the formula:

where R and R can be the same or different and are selected from the group consisting of hydrogen and lower alkyl groups having from 1 to 3 carbon atoms and wherein the amount of said nitrogen containing compound is at least that amount stoichiometrically required to achieve the desired acid number reduction;

at a temperature from 200 F. (933 C.) to the thermal cracking temperature of said petroleum fraction;

with a solid catalyst having a surface area greater than 15 m. /g., said solid catalyst comprising an oxide of a metal selected from the group consisting of the metals from Group IVB; aluminum; germanium; tin; lead; zinc; and cadmium;

and thereafter recovering a petroleum fraction having an acid number of less than 0.1.

In a preferred embodiment, the hydrocarbon fraction primarily in the liquid phase is passed through a bed of the defined solid catalyst.

CHARGE STOCK The charge stock for the process of this invention may be any hydrocarbon fraction but in particular a distillate hydrocarbon oil boiling above 330 F., preferably between 330 F. and 650 F. (165.5 C. and 343.3 C.) at atmospheric pressure and having an unacceptably high acid number, as measured by ASTM method D974, typically in excess of 0.1, usually 0.1 to 5. Desirably, the charge stock is a petroleum derived furnace oil or distillate No. 2 fuel oil which boils between 330 F. and 650 F. (165.5 C., and 3433" C.), although diesel fuels, industrial heating oils, mixtures of the above, and certain acid containing lube oil fractions are also suitable feed stocks for the process of this invention. Hydrocarbon fractions derived from coal, shale or tar sands can also be employed. The fractions are obtained by atmospheric or vacuum distillation techniques or by any other suitable separation procedure from acid containing crude oils; liquid coal fractions; etc.

The distillate fuel oil charge stocks described above are not marketable for reasons given above due to the presence of small amounts of the carboxylic acids such as naphthenic acids. Usually, but not necessarily, the distillate fuel oils also contain small amounts of cresylic acids. The cresylic acid content is not determined by the ASTM method D974. In accordance with this invention, it is proposed to reduce primarily the carboxylic acid content which may be present. While it is not certain, it is theorized that the acids are converted to amides by reaction of the acids with the nitrogen compound, e.g. NH The best known catalysts for amiding are strong aqueous mineral acids such as sulfuric acid. Unfortunately the reaction is reversible in the presence of water and heat. This reaction is shown in Equation I below:

Equation I i ll R-C-OH NH] "4 R-C-NHz E20 StrougAciTfCatalyst Fortuitously a solid catalyst has now been discovered which promotes the irreversible formation of compounds, believed to be amides, from the reaction of the acidic constituents of the distillate fuel oils with, for example,

ammonia. REACTANTS The nitrogen containing compound reactant which is added to the charge stock has the formula:

Where R and R can be the same or different and are selected from the group consisting of hydrogen and lower alkyl groups having from one to three carbon atoms. Examples of suitable nitrogen containing compounds include ammonia, methylamine, dimethylamine, ethylamine, methylethylamine, propylamine and dipropylamine. The preferred nitrogen containing compound is ammonia.

The amount of the nitrogen containing compound to admix with the hydrocarbon charge stock is not critical but should be at least that amount which is stoichiometrically required to reduce the acid number of the charge stock to the desired level. Preferably, the reactant is present in an amount equal to at least five to 20 times the stoichiometric amount necessary to reduce the acid number to the desired level. Since the acid number of the charge is normally low, the amount of the nitrogen containing compound expressed as -NH radical is usually from 0.143 to 0.572 weight percent of the charge stock for each acid number reduction of 1.0.

CATALYST The catalyst for the process of this invention is a solid catalyst having a surface area greater than 15 m. g. and comprises an oxide of a metal selected from the group consisting of the metals from Group IVB'; aluminum; germanium; tin; lead; zinc and cadmium. The metals from Group IVB include titanium, zirconium and hafnium.

The metal oxide catalyst can be used in an unsupported form so long as the surface area of the metal oxide is at least 15 m?/ g. and is preferably from 50 to 550 m. /g., more preferably from 100 to 400 m. /g. The method of preparation of the unsupported metal oxides is not critical so long as the resulting product has the required surface area characteristics. Unsupported metal oxides having lower surface area characteristics than those defined above do not possess sufficient activity to be of interest for the subject reaction. All of the defined metal oxides above have two characteristics in common. First of all, all of the defined metal oxides are members of a class known as n-type semiconductor metal oxides. N-type semiconductor metal oxides are defined as semiconductors in which the current is carried predominantly by electrons (see Solid State Physics by A. J. Dekker (Prentice-Hall Inc.), Sec. 12-14. Secondly, the above defined metal oxides can exist in a valence state lower than that present in their commonly occurring oxide, i.e. the metal can occur in more than one oxidation state.

The preferred unsupported metal oxides include titanium oxide, aluminum oxide, zirconium oxide, tin oxide and zinc oxide. The most preferred metal oxides are those formed from titanium and aluminum.

' While the method of preparation of the unsupported metal oxides is not critical as noted above, the preferred method of preparation of the unsupported titanium oxide is by the hydrolysis of titanium tetrachloride at a pH in excess of 9.

The metal oxides defined above can also be distended on any suitable support material well known in the art. Suitable support materials include those supports normally used for this purpose such as alumina, silica or mixtures thereof, thoria or activated carbon. Thus alumina may serve as both a catalyst in its own right and as a support for the other metal oxides.

The supports should have a surface area of between 50 and 1000 m. /g., usually between and 600 mP/g. The supports also contain sufficient porosity and mean pore diameter to allow for the entrance and exit of the reactants and products. The usual mean pore diameter of the support is from 30 to 250 A. The amount of the metal to distend on the support can suitably be from 1 to 50 weight percent of the total catalyst and is preferably from 5 to 25 weight percent of the final catalyst. The metal in the final catalyst is present in the oxide form.

The method of dispersing the metal oxide on the support is not critical, and any methods well known to those having ordinary skill in the art can be employed. For example, the metal can be deposited from an aqueous or organic solution onto the support by the method of minimum excess solution, or the metal can be deposited by vacuum impregnation techniques. The metal is converted to the oxide form by normal calcination techniques.

The attached Figure illustrates one embodiment of the invention. A distillate fuel oil having an unacceptably high acidnumber generally greater than 0.1 is passed through line 2 and admixed with a desired amount of ammonia entering through line 4. The mixture is preheated in heater 6 and passes through line 8 downfiow through reactor 10 containing one or more fixed beds of a catalyst consisting of 5 to 25 weight percent titanium on alumina. The charge stock is primarily in the liquid phase. The product having a reduced acid number leaves reactor 10 through line 12 and enters a flash chamber 14 where any excess ammonia is removed overhead through line 16. The liquid products leave chamber 14 through line 18 to distillation zone 20 where light products are recovered overhead through line 22, distillate fuel oil is recovered through line 24 and heavy products are recovered through line 26.

REACTION CONDITIONS The reaction temperature is suitably from 200 F. (93.3" C.) to the thermal cracking temperature of the charge stock, e.g. usually about 700 F. It is one of the advantages of the process of this invention, however, that the reduction of the acid number can occur under relatively mild conditions. For example, the usual temperatures of reaction are between 200 F. and 490 F. (933 C. and 254.4 C.); preferably between 200 F. and 450 F. (93.3 C. and 232.3 C.) and more preferably between 250 F. and 400 F. (121.1 C. and 204.4 C.). The reaction pressure is suitably and preferably close to atmospheric, but higher and lower pressures from 15 to 100 p.s.i.g. can be employed if desired. The liquid hourly space velocity can suitably be from 1 to 20 volumes of charge per volume of catalyst per hour, with preferred space velocities from 1 to 10 v./v./hr. Thus the reaction times are typically from three minutes to one hour, with the usual reaction times being from six minutes to one hour.

The invention will be further described with reference to the following experimental work.

Alter the experimental runs were made using a South Louisiana furnace oil, a South Louisiana heavy distillate, or a Coastal Blend-2 (CB2DLM) distillate fuel, the properties of which stocks are given in Table I.

TABLE I.-INSPECTIONS OF ACIDIC FURNACE OILS South Louisiana South Louisiana Heavy distillate furnace oil heavy distillate fuel (CB-Z-DLM) R 9248 LR 5098 LR 16447 Gravity, D 287, APL 36. 5 35.1 34. 2 Total acid number, D 974. 0. 47 0. 47 0. 41 Color, D 1500 L 1.0 0. 5 Odor. Marketable Petroleum Sulfur, D 1266, wt percent 0.10 0. 10 0. Water, p.p.m 2A Carbon residue on 1% bottoms, D 524, wt. percent- 0.10 0.09 Aniline point, D 011, F- 102.2 (723 0.) 159.0 (70.0" 6.) Ash, D 482, wt. percent 0.02 0. 002 Stability, 10 hr. at 210 F.:

Existent insolubles, mg./600 g 0.4 0. 7 0. 5 Potential insolubles, rug/600 g 1. 2 1. 2 0. 8 Filtrate color, D 1500 L 1. L 1.0 L 0.5 Distillation, D 86, F.:

Over point 301 (132 0.) 347 (175 0.) 400 (204 0.) End point e54 (340 c.) 676 (353 c 644 (340 0.)

by vol. 00nd. at F- 424 (218 C.) 44.5 (229 C by vol. cond. at F- 44o 230 C.) 475 (240 0) 48s (253 0.) 50% by vol. cond. at 520 (271 0.) 532 (278 0) 542 (233 0. 00% by vol. cond. at F 590 (313 0.) 626 (330 0) 604 (313 c.) Recovery, percent- .7 98

Small scale catalyst research runs were made as well as larger scale process runs using the preferred catalysts. TABLE II The catalyst research runs were made in a Pyrex glass Properties of the gamma-alumina supports reactor, externally heated with a tube furnace controlled support number" SNHA manually by variacs 1n the early phases of the pro ect B 2 and by ECS temperature controllers in the later stages. ggg;,;,%,;, 21:3 23} The 011 and the Nl-I reactant were fed concurrently and g g g g mostly downflow although the results obtained in the gggfigg A I: g 1; a: 3 percen .2 10.6 catalyst screening runs were not affected by the flow 150 1O0Apercent PV m 263 direction. The cond1t1ons for the runs using NH were 1ggi8i.,percent 13.1 12.4 atmospheric pressure, 5 LHSV, -9 s.c.f. NH /bbL, and 6H0 1; ii; 2:3 the desired temperature. In general, the runs were termifig-g8 i. percent gxx 4g r en nated when the product oil exceeded an ac1d number of 30.20 A 52.3. 11.8 & 20-10 11., percent PV. 3, 3 7, 4 0.1 b ASTM D974 test procedures- 'I11 s w SO, smce 1H Awpemmw 0 0 the acid number specifications for fuel 0118 is 0.1. 30

The large scale process runs were made with the pre- 5 Greater than 90% gamma-alumina.

TABLE III Properties of the most promising Pl/A120 catalysts Ti level, wt. percent 6 12 20 Catalyst number RN BIB-23A RN 298-2511 RN 316-911 RN 316-2413 RN 330-1311 Support number SN 3-51177 SN 3-5A17 SN 3-5A77 SN 3-5A77 SN 3-5A77 Particle size, unit 20 X 20 x 40 14 x 30 20 x 40 14 x 30 BET area, mfl/g 191. 9 197. 8 148.0 108.9 130. 6 Average pore radius, A 51. 0 43. 8 51.2 43. 5 65. 8 Pore volume, cc./g 0. 49 0. 43 0. 38 0. 24 0. 43 300-250 A., percent PV. 1. 1 0. 6 1. 5 1.8 1. 6 250-200 11., percent PV 2. 1 1. 0 2. 8 3. 4 3. 7 200-150 A., percent PV-..- 9. 8 1. 7 11. 3 5. 8 7. 7 150-100 A., percent PV- 24. 6 7. 8 23. 7 12. 5 23. 3 100-80 A., percent PV 12.4 13.7 11.1 10.0 14. 3 80-60 A., percent PV 13.3 19. 8 11.3 16. 0 15. 8 -50 21., percent PV 6. 7 ll. 2 5. 3 9. 1 6. 2 50-40 A., percent PV- 5. 7 13. 9 6. 8 9. 1 8. 5 40-30 A., percent PV. 0. 7 12. 9 8.7 10. 8 11. 1 30-20 A., percent PV- 12.7 12. 9 13. 4 15.2 8. 2 20-10 21., percent PV- 4. 9 4. 4 4. 1 6.1 0 10-0 21., percent PV 0 0 0 0 0 ferred catalysts in an automated unit in order to determine the efiect of variations in the operation of the unit on catalyst life and to establish the effect of processing on oil properties. The reaction conditions for the runs in the process reactor were atmospheric pressure, 5 LHSV, 9 s.c.f. NH /bbl., and temperatures of 300 F. to 350 F. (148.8 C. to 176.7 C.) for most of the runs.

The most widely used support for the catalysts used in the runs below consisted primarily of gamma-alumina. The surface area of this alumina ranges from 150 to 350 m. /g.; its pore volume from 0.50 to 0.70 cc./g.; and its average pore radius is higher than 40 A. A detailed tabulation of the properties of two samples of this alumina appears in Table II. The properties of the preferred catalysts prepared using these aluminas are shown on Table III.

initially, batch runs were made at 200 F. and 300 F. (93.3 C. and 148.8 C.) treating the South Louisiana furnace oil (LR 9248, Whose properties are given on Table I above) with NH in the absence of a catalyst. The results are summarized in Table IV below.

Referring to Table IV, it can be seen the acid number was not significantly lowered. In the batch run, 80 cc. of oil were stirred continuously for 0.5 hours in contact with 500 cc./hr. of NH Further batch runs were made in a S-necked, 500 cc. round-bottom flask heated with an electrical mantle. The 3-necked flask was equipped with a vent, an ammonia sparger inlet and a thermowell. 300 cc. of a South Louisiana heavy distillate fuel oil (LR 5998), whose inspections are shown on Table I, were placed into the flask and were heated to a desired temperature in the presence of a nitrogen blanket. At this point the nitrogen flow was stopped and ammonia was sparged through the oil at a rate such that the ammonia injected at the bottom caused vigorous agitation of the oil, and excess ammonia was continuously vented. The runs were continued for varying times; the product cooled; and an acid number determination made. Runs were made both with and without the presence of various aluminas. The results are summarized in Table V below:

Referring to Table V, Example 3 shows that essentially no reduction of acid number is achieved thermally at a temperature of 531 F. (277 C.) after three hours. Example 6 shows that using a high surface area alumina, the acid number of the product at 513 F. (267 C.) is less than 0.03. Examples 4 and 5 show that at 520 F. '(27l.2 C.) the acid number of the product is still about 0.25 even after five hours of reaction using levigated alumina. Levigated alumina is a low surface area alphaalumina having a surface area of less than 3 m. /g. The levigated alumina used in Examples 4 and 5 was purchased from the Norton Company.

A series of catalyst research runs were made using the Pyrex glass reactor described above and gamma-alumina as the catalyst at temperatures from room temperature to 450 F. (25 C. to 232.2" C.) using the several furnace oil distillates whose properties are shown on Table I. These runs were made by passage of the preheated oil plus ammonia downflow through a bed of the alumina. These runs as Examples 7-19 are summarized in Table VI.

TABLE VI Efiect of N H; and temperature on the initial activity and life of the A1203 catalyst [Atmospheric pressure; 5 LHSV; 20 x 40 mesh gamma-alumina catalyst designated SN 3-5A17] Throughput of product oil Feedstock Temperature NH; rate, having an acid number s.c.f./bb1. number of less Ex. No. from Table I F. C.) than 0.1

7 LR 9248 Room temp. 0 20 Room temp B 10 50 Room temp. 10 45 19- LR 16447 450 (232. 2) 10 3500b There was some variation and occasional interruption in NH; during runs.

b Product acid number was 0.03 at end of run. Volumes of oil per volume of catalyst.

Referring to Table VI above, it can be seen that reasonable throughputs of acceptable oil were not achieved with the alumina until the temperature reached about 300 F. (176.7 C.) and above.

Another series of runs similar to Examples 7-19 was made using a 12% Ti on gamma-alumina catalyst. The catalyst was prepared in the following manner: (RN 298-25A).

(1) About 100 cc. of 20 x 40 mesh alumina (SN 3- 5A17), whose properties are given on Table II above, were calcined as 1000 F. (537.8 C.) for 16 hours. The dry weight of the support was 56.18 grams.

(2) TiCl (33.39 grams) was dissolved in enough nheptane to form 5 6 ml. of total solution.

(3) Solution (2) was impregnated onto the calcined alumina (1) by pouring the solution gradually over the support with continuous mixing of the support.

(4) Immediately thereafter, sufficient distilled water (27 cc.) was added to bring the impregnated alumina to the point of incipient wetness.

'(5) The product from (4) was oven dried for 16 hours at 250 F. (l2l.l C.) and thereafter calcined at 1000 F. (537.8 C.) for 16 hours.

The results of this series of runs are summarized in Table VII below as Examples 20-31.

Referring to Tables VI and VII, it can be seen that at 250 F. to 350 F., much higher throughputs of oil are achieved utilizing the titania on alumina catalyst. A complete comparison cannot be made at a temperature of 350 F. (176.7 C.) using the LR 16447 stock as both the alumina and the titania on alumina catalysts were both producing acceptable product having an acid number as low as 0.03 at throughputs in excess of 1155 volumes of oil per volume of catalyst.

TABLE VII Effect 01 NH; and temperature on the initial activity and life 01a 12% Ti on alumina catalyst [Atmospheric pressure; 5 LHSV; 12% T1 on alumina catalyst] Throughput of h Vproduct oil a rig an act Feedstock number of 0.1 number Temperature (vols. of oil Eqample from Catalyst from NH; rate, per vol. of number Table I Table III F. C.) s.c.f./bbl. catalyst) RN 298-25A Room temp. 0 23 RN 298-25A 150 (65.6) 10 63 RN 298-25A 250 (121. 10 230 RN 298-25A 300 (148. 10 445 RN 298-25A 350 (176.7) 10 1, 285 RN 298-25A 350 (176.7) 0 48 RN 316-9A Room temp. 9 30 RN 316-915. 150 (65. 6) 9 51.5 RN 316-9A 200 (93. 3) 9 45.6 RN 316-9A 250 (121.1) 9 526.9 RN 316-9A 300 (148. 8) 9 1, 050 RN 316-9A 350 (176. 7) 9 1,155

9 Runs were then made to illustrate the effect of the level of Ti on the useful life of the alumina supported catalyst. These runs are summarized in Table VIII below.

TABLE VIII Effect of Ti level on useful life of A120: supported catalyst [Atmospheric pressure; 350 F. (176.7 0.); LHSV; 20 x 40 mesh catalyst; S. La. furnace oil, LR 5998; and about 10 s.c.f. of NH; per barrel of oil] Throughput of product Ti oil (vols. of 10 cone, oil per Acid number wt. volume of of final percent catalyst) product oil Example number:

Referring to Table VIII, both the 12% and Ti on A1 0 catalyst appear to be more active and stable than the Ti catalyst. The 20% Ti catalyst appears to have better aging characteristics. 20

A series of runs was made to study the effect of the nature of the support on the activity and life of Ti catalyst as shown in Table IX below.

TABLE IX 10 A series of small-scale runs was also made to study the use of unsupported Ti0 as a catalyst for the process of this invention. The results are tabulated in Table XI below.

TABLE XI On-stream life of indicated mategsgls for acid number reduction with [Atmospheric pressure; 5 LHSV; 9 s.c.t. N Hs/bbl. 350 F. (176.7 C.)]

Throughput of 0.1 BET acid area, number) oil Composition malg. (vol./vol.)

Example number:

43 TiOr e 103 3, 275 44.-. TiOz b 103 4, 368 45.. TiOi 32 384 46 90:10 TiOz- 80 396 A120 a 47 TiOr 348 48 T102 (anatase) 3 30 a Low pH hydrolysis of TiCh.

High pH hydrolysis of TiClr.

' Sulfate derived hydrate.

Product acid number=0.03 at 36 days.

Referring to Table XI above, it can be seen that the Efiect of the nature of the catalytic suppoitlontthe activity and life of the supported Tl ca a ys [Atmospheric pressure; 350 F. (176.7 0.); 5 LHSV; S. La. furauce oil (LR 5998); s.c.t.

NHs/bbL; 20 x 40 mesh catalyst] Nu-Char is the trade name for a low density charcoal.

b Divison Grade silica gel (SN 3-2B6).

Porous glass spheres. Ti appeared to flake off the bead.

' The product acid number was 0.03 at the end of the run.

a The run temperature was increased from 250 to 350 F. as the catalyst deactivated at each temperature.

Referring to Table IX, only the silica gel approaches alumina in activity and life.

Investigations were also made regarding the effect of other metal oxides in lieu of titania for acid number reduction, and the results are summarized in Table X below.

TABLE X low surface area TiO (anatase) is not too active, but the higher surface area materials are. It is believed the TiO of Example 47 possessed poor activity due to the presence of sulfate in the material. It is preferred that the catalysts of this invention be substantially sulfate Effect of the nature of the phase supported on A1103 in furnace oil neutralization [Atmospheric pressure; 350 F. (176.7 (3.); 5 LHSV; S. La. furnace oil (LR 5998), -9 s.c.f.

NHa/bbL; 20 x 40 mesh catalyst] Throughput of neutralized Pore Average oil having an Ex. Catalyst volume pore Area, acid number of N 0. Description number (cc./g.) radius, A mfl/g. 0.10 (voL/vol.)

39 12%Ti/A120a RN 29825A 0. 43 43. 8 197. 8 e 1, 285 12% Zn/AlzOs RN 316-26A 0.45 60. 5 148. 2 l, 050

12% Zr/AlzOa RN 31627A 0.27 47. 7 114. 7 l, 650

42 12% Bil/A1203 RN 316-25A 0. 47 51.3 181. 5 508 The product acid number was 0.03 at the end of the run.

Referring to Table X above, it can be seen that zinc, zirconium and tin also form active catalysts for the process of this invention.

Large scale runs with Ti/AlzOa catalysts free. The preferred surface areas are in excess of 50 m. g. and preferably in excess of nn g. Y

A summary of several large scale runs is shown in Table XII below.

TABLE XII [Atmospheric pressure; 5 LHSV; indicated temperatures and reactants] Fresh Catalyst throughput of Feedstock Temperature 0.1 acid number oil Example number from number Table I Catalyst F. C.) Reactant Vol/vol.

49 LR 5998 12% 'Ii/AlzOa (RN 316-914) 300 (148. 8) -9 s.c.f. N Ha/bbl. 1, 236

12% Ti/Alzoa (RN 316-911) 300 (148. 8) -9 s.c.f. NHs/bbl. 2, 856 20% Tl/Alzoa (RN 330-1314) 300 (148.8) -9 s.c.f. NHs/bbl. 2, 844 20% CPI/A1203 (RN 330-13A) 350 (176. 7) -13 s.c.f. NHa/bbl. 5,124

a Product acid number at end of run=0.05.

Referring to Table XII, Example 49 was run with a South Louisiana furnace oil while the remaining Examples 50-52 used a heavy distillate (Coastal Blend) derived from a different crude source. A comparison of Examples 49 and 50 at the same conditions shows a much longer life for the catalyst using the latter stock. Apparently an increased Ti content from 12 to 20% has no effect using the Coastal Blend charge (Examples 50 and 51). Increased temperatures of 350 F. improve catalyst life as shown by a comparison of Examples 51 and 52.

Resort may be had to such variations and modifications as fall Within the spirit of the invention and the scope of the appended claims.

We claim:

1. A process for reducing the acid number of a petroleum fraction having an acid number in excess of 0. 1 which comprises:

contacting said petroleum fraction and a nitrogen containing compound having the formula:

R! RILTH where R and R can be the same or different and are selected from the group consisting of hydrogen and lower alkyl groups having from 1 to 3 carbon atoms and wherein the amount of said nitrogen containing compound is at least that amount stoichiometrically required to achieve the desired acid number reduction;

at a temperature from 200 F. to the thermal cracking temperature of said petroleum fraction;

with a solid catalyst having a surface area greater than 15 m. /g. comprising an oxide of a metal selected from the group consisting of the metals from Group IVB; aluminum; germanium; tin; lead; zinc; and cadmium;

and thereafter recovering a petroleum fraction having an acid number of less than 011.

2. 'A process according to claim 1 wherein the petroleum fraction is a distillate petroleum fraction; the nitrogen containing compound is NH;,; and the solid catalyst comprises an oxide of a metal selected from aluminum and titanium and wherein said solid catalyst has a surface area from 50 to 550 m. g.

' 3. A process according to claim 2 wherein the oxide of titanium is deposited on a support.

4. A process according to claim 3 wherein the support is alumina and wherein said contacting occurs at a temperature from 200 F. to 490 F.

5. A process according to claim 4 wherein the catalyst contains from 5 to 25 weight percent titanium.

6. A process according to claim 5 wherein the charge stock is a distillate petroleum fraction boiling between 330 F. and 650 F.

7. A process for reducing the acid number of a hydrocarbon fraction having an acid number in excess of 0.1 which comprises:'

passing said hydrocarbon fraction primarily in the liquid phase together with a nitrogen containing compound having the formula:

where R and R can be the same or different and are selected from the group consisting of hydrogen and lower alkyl groups having from 1 to 3 carbon atoms and wherein the amount of said nitrogen containing compound is at least that amount stoichiometrically required to achieve the desired acid number reduction;

through a bed of a solid catalyst having a surface area greater than 15 m. /g. comprising an oxide of a metal selected from the group consisting of the metals from Group IVB; aluminum; germanium; tin; lead, zinc; and cadmium at a temperature from 200 F. to the thermal cracking temperature of said hydrocarbon fraction;

and thereafter recovering a hydrocarbon fraction having an acid number of less than 0.1.

8. A process according to claim 7 wherein said nitrogen containing compound is ammonia; said hydrocarbon fraction is a distillate petroleum fraction; the amount of ammonia is from 5 to 20 times the required stoichiometric amount; said solid catalyst has a surface area from 50 m. /g. to 550 m. /g.; and the reaction temperature is from 200 F. to 700 F.

9. A process according to claim 8 wherein the solid catalyst has a sunface area from to 400 m. /g. and the reaction temperature is from 250 F. to 490 F.

10. A process according to claim 9 wherein said catalyst is at least one metal oxide selected from the group consisting of alumina; titania; zirconia; tin oxide; and zinc oxide.

11. A process according to claim 10 wherein the catalyst is alumina.

12. A process according to claim 10 wherein the catalyst is unsupported titania.

13. A process according to claim 10 wherein the catalyst is from 5 to 25 weight percent titanium present as the oxide on alumina.

14. A process according to claim 13 wherein the reaction temperature is from 250 F. to 400 F.

15. A process according to claim 10 wherein the catalyst is from 5 to 25 Weight percent zirconium present as the oxide on alumina.

16. A process according to claim 10 wherein the catalyst is from 5 to 25 weigh-t percent zinc present as the the oxide on alumina.

17. A process according to claim 10 wherein the catalyst is from 5 to 25 weight percent tin present as the oxide on alumina.

References Cited UNITED STATES PATENTS 2,302,281 11/1942 Watkins -208289 2,434,839 l/l948 Davis 208289 3,182,016 5/1965 Cole et a1. 208264 3,303,859 4/1967 Doane 208--2 64 DELBERT E. GANTZ, Primary Examiner J. M. NELSON, Assistant Examiner US. Cl. X.R. 208289

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