US2840512A - Stabilization of furnace oil by hydrotreating to remove sulfur and gum - Google Patents

Description

June 1958 w. P. BURTON ETAL 2,840,512

STABILIZATION OF FURNACE OIL BY HYDROTREATING TO REMOVE SULFUR AND cum Filed Sept. 29, 1955 3 INVENTORS w WILLIAM P. BURTON CHARLES E.SLYNGSTAD ATTORNEYS United States Pfltfiflt O STABILIZATION OF FURNACEOIL BY HYDRO- TREATING TO REMOVE SULFUR AND GUM William P. Burton, Little Silver, and Charles E. Slyngstad, Rutherford, N. J., assignors to The M. W. Kellogg Company, Jersey City, N. J., a corporation of Delaware Application. September 29, 1955, Serial No. 537,414

4 Claims. (Cl. 196-24) This invention relates to a method of stabilizing a furnace oil'without effecting a change in color.

Furnace oils are used extensively in home burners and commercial installations for heating, etc. At present, there is found in furnace oils gum-forming compounds or constituents which will, upon standing, produce gum-like materials. These gum-like materials are not desired, because in the type of equipment used for burning furnace oils, the gum-like materials will clog the equipment causing operating difliculties. At present, it is not clearly understood what kind of compounds produce the undesired gum-like materials. Further, furnace oils contain color bodies or compounds which impart to the oil a color other than a colorless appearance. These color bodies do not cause operating difficulties in the equipment used for the burning of furnace oils, therefore, for the purpose of this invention, it is not intended to effect any change in the color of the oil. In addition to the color bodies and the gum-forming compounds, the furnace oils do contain sulfur compounds. The combustion of sulfur compounds in the furnace oil may produce corrosion of the equipment used for such a purpose as well as to produce an undesired smell or contamination of the surrounding atmosphere. It is apparent, therefore, that there exists a need for a process whereby furnace oil can be stabilized, with or without simultaneous removal of sulfur and without a change in color.

An object of this invention is to provide a process for the stabilization of furnace oils without a, change in color.

Another object of this invention is to provide a method for the desulfurization and stabilization of furnace oils without changing the color. I

Other objects and advantages of this invention will become apparent from the following description and explanation thereof.

By means of the present invention, a furnace oil is stabilized without a change in color by the process which comprises contacting the furnace oil containing gumforming constituents with a cobalt molybdate. catalyst under suitable reaction conditions including a temperature not greater than 700 F. and a weight space velocity of at least about 5.

The furnace oil to bev processed by means of the present invention contains gum-forming constituents. The determination of the gum-forming tendency of the furnace oil or its stability is made by a simple testin which the oil is subjected to a temperature of 210 F. for a period of 40 hours. If the oil does not change more than /2 NPA in color and not more than 5 milligrams of gum is produced per 600 grams of oil sample, it is considered stable. This test is used for the purpose of determining the stability in the present specification and the appended claims. While the gum-forming compounds or constituents in the furnace oil are not known at present, nevertheless the stability test is sufficient for the purpose of determining the nature of a particular furnace oil. In addition to. stability, furnace 'oils usually contain color. Here again, at present, the color bodies or compounds imice parting color to the furnace oil are not clearly understood, although it is speculated that nitrogen compounds usually produce color, in hydrocarbon oils. For the purpose of this invention, the furnace oil can contain an NPA color ranging from about 1 to about 6 or on a Saybolt scale, the color of the furnace oil can range from about I6 to about +30. In addition to containing color and gumforming compounds, the furnace oil may also contain sulfur compounds. The sulfur concentration of a furnace oil can vary widely such as, for example, about 0.1 to

about 4% by weight of sulfur. The sulfur content of the oil will be reduced under the conditions employed for the purpose of effecting stabilization. The furnace oil employed for the purpose of this invention will have an initial boiling point of about 300 to about 420 F. and an end point of about 500 to about 850 F., more usually, the furnace oil will have an initial boiling point of about 325 to about 350 F. and an end point of about 550 to about 650 F. The furnace oil to be treated can be a mixture of virgin or straight run stock and what is usually refered to as light cycle oil, as well as heavy cycle oils.

The furnace oil is treated by means of a cobalt molybdate catalyst. Forthe purpose of this specification and the appended claims, cobalt molybdate is intended to include a mixture of cobalt oxide and molybdenum oxide as well as the compound cobalt molybdate. It is believed that under the conditions employed for the purpose of treatment in accordance with this invention, it is not important whether a mixture of the oxides is used or whether cobalt molybdate is the catalyst at the start of the operation. Accordingly, the catalyst of this invention contains about 0.5 to about 10% of cobalt oxide, based on the total weight of the catalyst, and it contains about 5 to about 25% of molybdenum oxide, e. g., molybdenum trioxide, based on the total weight of the catalyst. The cobalt molybdate is supported on a suitable carrier material, such as for example, alumina, silica-alumina, halogenated alumina, activated charcoal, kieselguhr, pumice, zinc aluminate spinel, etc. When silica is employed in combination with alumina, it constitutes about 0.5' to about 5%, based on the total weight of the catalyst. Chemically combined halogen such as, for example, chlorine or fluorine, can be used in the catalyst in the amount of about 0.1 to about 8%, based on the total weight of the catalyst.

'The furnace oil is treated with cobalt molybdate catalyst under carefully selected conditions. In this respect, it is essential to the present invention that the temperature of treatment is not higher than about 700 F. and the weight space velocity is at least 5. In this respect, should either thetemperature or the weight space velocity fall outside of the range given above, it is noted that there is a color change, and hence, such an operation falls outside the scope of this invention. In general, the temperature of treatment can vary from about 550 F. butnot greater than about 700 F. The weight space velocity, measured as the pounds of oil per hour charged to the reaction zoneper pound of catalyst present therein, is at least. about 5 and. it can be as high as 20. It was found that the pressure of operation can be as low as about p. s. i. g. and it can be as high as 1500 p. s. i. g., more usually about 300 to about 1000 p. s. i. g. The reaction.

a hydrogen rate of up to about 2000 S. C. F. B. sufiices for the purpose of this invention. Consequently, it can bev seen that the present invention can be operated within rather narrow ranges of conditions, for example, a high 3' hydrogen rate of about 300 weight space velocity of about 5 to about 15 and a reaction pressure of about 300 to" about 600 p. s. i. g. Under the conditions of operation, at least part of the sulfur content in the furnace oil is removed, the oil is stabilized and the color remains unchanged.

In order to provide a better understanding of this invention, reference will be had to the accompanying drawing which contains a schematic diagram of a test unit which was employed for. the purpose of evaluatingthis invention.

1 Inthe drawing, oil feed is supplied by means of line 5 at the desired flow rate and it is combined with hydrogen being supplied from line 7, and thence, the combined steam flows throughline 8 before entering preheater 10. In the preheater, the temperature'is raised to the desired temperature, for example, about, 600 to about 700 F., and thereafter, it flows through line 12 before it enters the top of reactor 14. Reactor 14 is 43 inches in length andll inches in diameter, and it contains about 800 grams of catalyst. The catalyst is in the-form of 35 inch pellets. Under the conditions prevailing in the reactor, theffurnace oil is stabilized with removal of sulfur and without change in color. The vaporous reaction product is discharged from the bottom of the reactor by means of line 15,;and hence, it enters a water cooler 17 wherein the temperature is reduced to about 80 F. The cooled reaction product contains condensed normally liquid product material, or material which is present as a liquid under reaction pressure and the temperature to which the material was cooled; The cooled reaction product flows from cooler 17 -by means of line 20.

. A preliminary separation of normally gaseous product materialfrom liquid product eflected ,in primary'receiver l9, consequently, the normally gaseous product material flows overhead therefrom by means of line 22;

Whereas the liquid product is discharged from the bottom by means of line 23. Any liquid product which is entrained in the normally gaseous product is separated in the secondary receiver 25 and it is discharged'from the bottom thereof by means of valved line 27. The gaseous product is discharged overhead from the secondary. receiver. 25 by means of line 28. The liquid product in lines 23 and 27 flow into line 30'which contains. a pressure) reducing valve 31. By means of valve 31, the pressure; ,is reduced to atmospheric level and the total product passes into a low pressure receiver 32. Any gaseous product which is released from the liquid product in receiver 32 is discharged therefrom by means of line 34 and it is measured by means of meter35 before being vented from the system by, means of line 36. Liquid product is dis- 5 in a closed position. Hydrogen can be purged from the o 1 system via line 46. Fresh hydrogen is supplied from a valved line 50, and it flows to line 51 before being measured by means of, meter 53. The measured hydrogen flows from'meter 53 to line 55 where, in the case of the recycle gas: operation, it combines with recycle gas flowing through line 42 and the combined stream flows through line 57. The total hydrogen stream is measured by meansof meter 59, and thence, it flows intoline 7 beforecombining with feed which is flowing to the preto about 900 s. c. F. 15., a o

' 4 a mixture with the air in case a diluted air stream is desired for the regeneration.

The feed stocks evaluated for the purpose of this invention are given in Table I below.

Table I Feed A B 0 D API Gravity 24. 0 23.8 29.9 33. 4 ASTM Distillation, F.:

IBP 386 433 466 326 472 481 504 408 639 536 536 518 605 608 600 586 E. P 649 644 642 639 Sulfur, Wt. percent 1. 02 2.13 0. 21 0. 18 Color, NPA 2 3% 2 1% heater l0. For the purposeof regeneration, air can be supplied from a valved line 61 and valved line 50-can be employed for the purpose of supplying nitrogen for ad The catalyst employed for this evaluation consisted of cobalt molybdate supported on alumina. The catalyst contained 4.1% by weight of cobalt oxide, 12.0% by weight of molybdenum trioxide and the remainder was alumina. e

The data reported in Table 'II below serves to illustrate thecritical feature of temperature when it is desired to stabilize furnace oils without changing color.

I 807 hydrogen.

a hydrogen.

\1 Stable oil is defined herein as changing not more than $6 NPA color and producing no more than 5 mg. gum/600 gm. 011 during the stability test oi 40 hours in a 210 F. oven.

It is apparent from the data given above in Table II that as long as the temperature was above 700 F., notwithstanding that all other conditions fall within the range tobe used for the treatment of furnace oil in accordance with this invention, the oil product was stabilized with a change in color.

Additional experiments were performed and reported in Table m below. a

Table 111 Run N0 1 2 a 4 Feed A A A A Pressure, p. s. l. g 400 400 400 400 Space Vel., W.,/hr./W... l 5 10 10 Temperature, F 700 700 700 780 H; rate, S. C. F. B 500 520 520 480 Results Feed Products Sulfur, we. percent"; 1 02 0,05 0. 24 0.38 o. 21 Color, NPA 2' 2 2 8% Stability N 0 Yes Yes Yes Yes a It is apparent from the data contained in Table III above thatwhere the temperature was 700 F. and the weight space velocity was at least 5, the furnace oil was stabilized without a change in color. However, where the temperatureof treatment was 700" F. and the weight space velocity was below 5, the oil was stabilized with a change in color. Further, when etfecting the treatment above 700 F. with a weight space velocity of 10, it is noted that the oil was stabilized with a change in color.

Further evaluation of the present invention was made and the results are reported in Table IV below.

Table IV Run No 1 2 Fee A A Pressure, p. s. i. g 400 400 Space Vel., W r./Wc 1.0 1. 0 Temperature, F 700 700 H: rate, S. C. F. B 500 2,000

Results Feed Products Sulfur, Wt. Percent 1. 02 0. 0. 05 Color, NHL... 2 4 3 Stabi1ity N 0 Yes Yes The data in Table IV above indicate that even though a higher rate of hydrogen is employed for the treatment just so long as the weight space velocity falls below 5, the furnace oil is stabilized with a change in color.

An additional experiment was performed and reported in Table V below.

Table V Run No 1 Feed 0 Pressure, p. s. i. e 600 Space Vel., W.,/hr./W., 5 Temperature, F 700 H; rate, S. O. F. B 800 Results Feed Product Sulfur, Wt. Percent 0. 2 0. 03 Color, NPA 2 2 Stability No Yes It is noted from the run made and reported in Table V above that the critical aspects of temperature and weight space velocity are not disturbed by using a higher'pressure of treatment.

Another experiment at low pressure was performed and reported in Table VI below.

is possible to operate at as low as p. s. i. g. with only a very small change in color in the oil treated to provide a stable oil of substantially lower sulfur content.

Having thus provided a written description of this invention along with specific examples thereof, it should be understood that no undue restrictions or limitations are to be imposed by reason thereof, but that the scope of the present invention is defined by the appended claims. We claim:

1. A process for stabilizing a furnace oil containing gum forming constituents without changing the color thereof which comprises contacting the furnace oil with a cobalt molybdate catalyst under suitable reaction con ditions including a temperature not greater than about 700? F. and a weight space velocity of at least about 5.

2. A process for stabilizing a furnace oil containing gurn forming constituents without changing the color thereof which comprises contacting the furnace oil with a cobalt molybdate catalyst under suitable conditions including a temperature not greater than about 700 F., a weight space velocity of at least about 5, a hydrogen rate in the amount of at least about 300 S. C. F. B. and a pressure of at least about 150 p. s. i. g.

3. A process for desulfurizing and stabilizing a furnace oil containing gum forming constituents and sulfur compounds without changing the color thereof which comprises contacting the furnace oil with a cobalt molybdate catalyst under suitable desulfurization conditions including a temperature not greater than about 700 F., a weight space velocity of at least about 5, a pressure of about 150 to about 1500 p. s. i. g. and in the presence of added hydrogen in the amount of about 300 to about 2000 8.0. F. B.

4. A process for desulfurizing and stabilizing a furnace oil containing gum forming constituents and sulfur compounds without changing the color thereof which comprises contacting the furnace oil with a cobalt molybdate catalyst under suitable conditions including a temperature of at least about 550 F. and not higher than about 700 F., a weight space velocity of about 5 to about 20, a pressure of about 150 to about 1500 p. s. i. g. and in the presence of added hydrogen in the amount of about 300 to about 2000 S. C. F. B.

References Cited in the file of this patent UNITED STATES PATENTS 2,587,987 Franklin Mar. 4, 1952 2,608,521 Hoog' Aug. 26, 1952 2,694,671 Baumgarten et a1. Nov. 16 1954 2,717,857 Bronson et al. Sept. 13, 1955 OTHER REFERENCES Zohnstecher et al.: Oil and Gas Journal, vol. 53, December 20,1954, pages 78 to 81. r

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,840,512 June 24, 1958 William P, Burton et al It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3 line 15, for "steam" read stream line 26, for

"hence" read thence Signed and sealed this 19th day of August 1958,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents

Claims (1)

1. 4. A PROCESS FOR DESULFURIZING AND STABILIZING A FURNANCE OIL CONTAINING GUM FORMING CONSTITUENTS AND SULFUR COMPOUNDS WITHOUT CHANGING THE COLOR THEREOF WHICH COMPRISES CONTACTING THE FURNACE OIL WITH A COBALT MOLYBDATE CATALYST UNDER SUITABLE CONDITIONS INCLUDING A TEMPERATURE OF AT LEAST ABOUT 550*F. AND NOT HIGHER THAN ABOUT 700*F., A WEIGHT SPACE VELOCITY OF ABOUT 5 TO ABOUT 20, A PRESSURE OF ABOUT 150 TO ABOUT 1500 P. S. I. G. AND IN THE PRESENCE OF ADDED HYDROGEN IN THE AMOUNT OF ABOUT 300 TO ABOUT 2000 S. C. F. B.

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