US2846361A - Asphaltite treating - Google Patents

Description

Aug. 5, 1958 INVENTOR ATT RN E5 ASPHALTITE TREATING Valentine Mekler, Jackson Heights, N. Y., assignor to The Lummus Company, New York, N. Y., a corporation of Delaware Application September 1, 1953, Serial No. 377,936

Claims. (Cl. 19650) This invention relates to the treatment of the class of material known as asphaltites to provide a suitable feed for a contact coking operation.

The asphaltites are natural asphalt-like substances characterized by their high fusing points. They are generally grouped into three classes, namely gilsonite, glance pitch and grahamite. This invention is particularly concerned with solid gilsonite, which has a softening point in the order of 270 F. to about 400 F., normally containing less than 5% volatile matter and having a fixed carbon content in the range of -20%. Gilsoniteis particularly characterized by the fact that when heated to a temperature above 600700 R, there is formed a considerable quantity of gas and the release of substantial quantities of heat.

Despite the fact that gilsonite offers a source of valuable hydrocarbons, the difiiculties present in heating gilsonite to the extent necessary to process or handle the gilsonite as a coker charge have made a commercial process for the recovery of valuable constituents of the same impractical.

Normally if a powdered form of gilsonite is mixed With a liquid hydrocarbon and heated to temperatures below the 600700 F. temperature, it is possible to remove the undesired gaseous components, particularly nitrogen, and produce an asphalt-like charge that can be ultimately reduced to dry coke. This reduction to dry coke can be accomplished by charging the asphalt to apparatus such as delayed or continuous coking units suited for that purpose without unwarranted frothing or foaming in the apparatus and without unwarranted formation of coke in the system.

In order to carry out my invention, it is necessary to have suificient hydrocarbon liquid present with the ground gilsonite to carry it through the gasification stage so that the gaseous components may be effectively removed without the formation of exothermic heat.

I have found that a liquid having a boiling range of between 350-600 P. will provide a means of carrying the hot gilsonite to a fractionation operation in which the gaseous components produced on heating the gilsonite will be efiectively separated from the gilsonite charge. A liquid of such a boiling range will be distilled along with the components of gasification from which the liquid can be condensed, separated and returned to a melting tank. The temperature of the returned liquid should be maintained sufficiently high to melt the powdered gilsonite charge without additional heating. If desired, a liquid of lower boiling range may be used. However, the relatively high softening point of the gilsonite requires a carrier of the stated preferred range. A liquid of considerably higher end point could conceivably be used, but operations with such a liquid would require distillation temperature in the critical temperature area 600- 700 F. at which the exothermic reaction of the gilsonite may occur. It is one of the objects of my invention to accomplish the gasification and removal of the products P ice of gasification from the gilsonite without such an exothermic reaction occurring.

In addition to removing the undesired gases from the gilsonite, my invention further contemplates the reduction of the liquid residue from the fractional distillation step to a charge which may be effectively used in a coking operation of the type described in the co-pending application of August Henry Schutte, Serial No. 252,306, filed October 20, 1951, now abandoned.

The attached drawing shows a schematic view of the equipment necessary for the treatment of gilsonite to remove undesired constituents and to prepare the gilsonite for further processing.

In accordance with a preferred form of embodiment of my invention, ground or pulverized gilsonite obtained from a collection source such as a hopper or other means not shown, is introduced at a desired rate by conveying mechanism 10 into a melting tank 12. The capacity of tank 12 can be varied in accordance with the amount of gilsonite charged. To enhance the mixing of the powdered gilsonite and the liquid hydrocarbon carrier, agitators 14 are provided.

A suitable quantity of liquid carrier is introduced into the tank 12 by means of line 16 from a make-up source not shown, or is recycled from the fractionation operation as hereinafter described. I have found it desirable to maintain the liquid carrier at a temperature of approximately 500 F. The powdered gilsonite will at temperatures in this range form a pumpable slurry.

The slurry or mixture of powdered gilsonite and liquid hydrocarbon is Withdrawn from the tank 12 by way of line 18 and passed to a conventional heater 20 having appropriate coils or tubes 22 therein. The liquid carrier used should have a boiling range of between 350-600 F. and is generally used in an approximate ratio of one part by weight of carrier to one part by weight of the powdered gilsonite. The temperature of the slurry in heater 20 is maintained at about 600 F., sulficient to cause the gaseous components to be removed from the gilsonite charge. It is essential that the temperature be kept below 700 F. at which temperature decomposition of gilsonite begins, causing the formation of coke and plugging of the coils in the heater.

I have found that if suflicient amounts of carrier are present during the heating stage and the temperatures of the heating operation is controlled so that the undesired exothermic reaction is avoided, substantially complete removal of gaseous components of the gilsonite can be obtained.

The efliuent from the heating operation, which is passed by way of line 24 to an atmospheric distillation tower 26, has the general appearance of a fuel oil. This material is introduced into the column at a temperature of approximately 600 F. The introduction of the effluent into the tower results in a considerable frothing or foaming due to the presence of the undesired constituents which include nitrogenous, oxygenated and sulfurous compounds. This mixture, including substantially all the vaporized hydrocarbon solvent is withdrawn as a tower overhead by line 31 and passed through condenser or cooler 32 and into a separator 33.

In the separator 33 non-condensible gasificatio-n products, such as nitrogen, sulfur dioxide, carbon dioxide and possibly carbon monoxide are Withdrawn through line 34 and vented to the atmosphere or to a further separation apparatus, if desired. The condensed hydrocarbon vapors are in part returned as a tower reflux through line 36 by means of pump 37. The remaining portion of the condensed carrier is returned by way of line 35 to the melting tank 12 to be added to fresh gilsonite continuously added thereto.

It is one of the important features of my invention to provide a continuous recycle of the liquid hydrocarbon carrier as a means of carrying the gilsonite through the gasification treatment with little loss of carrier, I provide a carrier make-up line 16 for adding carrier lost in the cycle during long periods of'operation.

The heavier boiling portion of the heater eflluent having the properties of a heavy fuel oil or asphalt is withdrawn as a bottoms product from the fractionation tower by way of line 39 and passed to a coking reactor 40.

The reactor 40 may be of a continuous contact type as "disclosed in August Henry Schuttes U. S. Patent 2,600,078, or a fixed bed coking apparatus, if desired. In the coking reactor the treated gilsonite is contacted with the coke particles present in the reactor. This results in a continuous vaporization of the lighter ends of the charge by the heated coke. The coke particles in a moving bed coker are transferred from the coking reactor through a reheater wherein the temperature is raised to a level suflicient to substantially vaporize, crack and convert the gilsonite charge into gas, gasoline, gas oil and coke. The products of the coking including the gas, gasoline and gas oil distillate are introduced into tower 44. Therein the light components are taken over head as a product through line 45, passedthroughcondenser 48 and into a separating tank 49. The gaseous components or light ends are withdrawn by way of line 50 and passed toa gas holder or other treatment, as-desired.

Unstable gasoline separated in 49 is withdrawn through line 51 and passed to further recovery through line 53. A part of the condensed overhead may be returned to column 44 by line 54 as reflux. Gas oil is withdrawn from an intermediate part of the column Maud passed to storage through line 52.

The gilsonite, when handled in accordance with my invention, has yielded the following:

1 Not including liquid carrier.

It will be evident from the foregoing that it is possible to obtain from a solid gilsonite charge valuable hydrocarbon products. Such recovery is made possible by the effective treatment of the gilsonite to produce a charge which can be satisfactorily handled in the coking operation. The novel manner in which I carry out the stabilization of the gilsonite without coking of the heater and with continuous liquid carrier recovery provides a process with considerable economic advantage.

While I have shown and described a preferred form-of my invention, I am aware that modifications may be made thereto and I desire a broad interpretation of the invention within the scope and spirit of the description herein and the claims appended hereafter.

I claim:

1. The method of treating solid gilsonite, which comprises introducing ground gilsonite into a melting tank containing a hot hydrocarbon liquid carrier boiling in the range of between 350 F. and 600 F. and maintained at a temperature suificient to melt the gilsonite introduced therein without exothermic reaction thereof, mixing the melted gilsc-nite and liquid carrier to form a pumpable slurry, introducing the slurry into a heater wherein the slurry is heated to a temperature of approximately 500 F. and sufficient to substantially remove undesirable gaseous constituents from the gilsonite and stabilize the same, controlling the heating operation to avoid coking of the gilsonite, passing the heater etfluent to a distillation column, withdrawing an overhead product from said distillation column comprising the undesirable gaseous constituents and liquid carrier, condensing the liquid carrier component of said overhead, separating condensed liquid carrier and the uncondensed gaseous constituents, withdrawing said gaseous constituents from the separation operation, passing a portion of the liquid carrier to the melting tank at a temperature sufiicient to maintain, the required temperature in the melting tank, withdrawing stabilized gilsonite from the bottom of the distillation column, introducing said gilsonite into a coking reactor, and withdrawing a solid coke product and hydrocarbon vapors from said coking reactor.

2. The method of treating solid gilsonite as claimed in claim 1 wherein the melting tank is operated at a temperature of between 400 F. and 550 F. and the heater is operated at a temperature below 600 F.

3. The method for treating gilsonite to provide a suitable coking charge whichi comprises, introducing ground gilsonite into a melting tank, introducing a hot hydrocarbon liquid carrier boiling in the range of between 350 F. and 600 F. into the tank in a ratio of one part by weight of carrier to one part by weight of the ground gilsonite whereby said ground gilsonite is completely melted by said hot liquid, agitating the carrier and solid to provide a pumpable slurry, withdrawing the said slurry and introducing the same into a heater, maintaining the slurry at a temperature of approximately 500 F. and sufficient to remove gaseous components from the gilsonite in-the absence of coking, Withdrawing an effluent from said heater, introducing. said efiiuent into a distillation column, withdrawing an overhead from said column comprising a major portion of liquid carrier and a minor portion of gaseous constituents, condensing said carrier, separating the gaseous constituents from the condensed carrier, returninga portion of the carrier to the column as reflux, returning the remaining portion of condensed carrier to the melting tank, withdrawing a stabilized.

asphalt bottoms from the distillation column, introducing said asphalt bottoms to a coking operation, withdrawing a vaporous product from said coking operation, introducing said product into a distillation column, withdrawing an overhead from said column, condensing said overhead and returning a portion of said overhead to the column, and withdrawing a bottoms product from said column and returning said bottoms to the coking reactor.

4. The method of treating gilsonite, which comprises forming a solution of ground gilsonite and hot hydro:

carbon liquid carrier boiling in the range of between 350 F. and 600 F., introducing the solution into a heater, maintaining the solution at a temperature of approximately 500 F. and sufiicient to remove gaseous components from the gilsonite without exothermic reaction thereof and in the absence of-coking, withdrawing an efiluent from said heater, introducing said efiiuent into a distillation column, withdrawing an overhead from said column comprising a major portion of liquid carrier and a minor portion of gaseous constituents, condensing said carrier, separating the gaseous constituents from the condensed carrier, returning a portion of the condenser carrier to the distillation column as reflux, returning the remaining portion of condensed carrier to the point of forming the said gilsonite solution, withdrawing a stabilized asphalt bottoms from the distillation column, introducing asphalt bottoms to a coking operation, Withdrawing a vaporous product from said coking operation, introducing said vaporous product into another distillation column, withdrawing an overhead from said, distillation column, withdrawing a bottoms product from said other distillation column, and returning said bottoms to the coking reactor.

5. The method for treating gilsonite to provide a suitable coking charge which comprises forming a solution of ground gilsonite and hot hydrocarbon liquid boiling in the range of between 350 F. and 600 F. and introducing the solution into a heater, maintaining the solution at a temperature of approximately 500 F. and suflicient to remove gaseous components from the gilsonite without exothermic reaction thereof in the absence of coke formation, withdrawing an efiluent from said heater, introducing said eflluent into a distillation column, withdrawing an overhead from said column comprising -a major portion of the solution liquid carrier and a minor portion of gaseous constituents, condensing said carrier, separating the gaseous constituents from the condensed carrier, returning a portion of the condensed carrier to the distillation column as reflux, returning the remaining portion of the condensed carrier to the point of forming the said gilsonite solution, withdrawing a stabilized asphalt bottoms from the distillation column, introducing the asphalt bottoms to a coking operation, withdrawing a vaporous product from said coking operation, introducing said vaporous product into another distillation column, withdrawing an overhead from said other distillation column, condensing said overhead and returning a portion of said overhead to the other column, and withdrawing a bottoms product from saidother column, and returning said bottoms to the coking reactor.

References Cited in the file of this patent UNITED STATES PATENTS 1,177,727 Smith Apr. 4, 1916 1,458,983 Kirby June 19, 1923 1,703,192 Hampton Feb. 26, 1929 1,714,963 Trumble May 28, 1929 1,907,569 Parr et al May 9, 1933 1,936,881 Rose et al Nov. 28, 1933 1,993,198 Wisner Mar. 5, 1935 2,661,326 Stillman Dec. 1, 1953 2,726,196 Bloomer Dec. 6, 1955 FOREIGN PATENTS 250,699 Great Britain Apr. 22, 1926 OTHER REFERENCES Roberts: Oxidation and Preheating Systems of Coal Carbonisation, Coke and Gas, November 1948, pp. 377-380.

Robinson and Gilliland: Elements of Fractional Distillation, 4th ed. (1950), pages 137-138.

Claims (1)

1. THE METHOD OF TREATING SOLID GILSONITE, WHICH COMPRISES INTRODUCING GROUND GILSONITE INTO A MELTING TANK CONTAINING A HOT HYDROCARBON LIQUID CARRIER BOILING IN THE RANGE OF BETWEEN 350*F. AND 600*F. AND MAINTAINED AT A TEMPERATURE SUFFICIENT TO MELT THE GILSONITE INTRODUCED THEREIN WITHOUT EXOTHERMIC REACTION THEREOF, MIXING THE MELTED GILSONITE AND LIQUID CARRIER TO FORM A PUMPABLE SLURRY, INTRODUCING THE SLURRY INTO A HEATER WHEREIN THE SLURRY IS HEATED TO A TEMPERATURE OF APPROXIMATELY 500*F. AND SUFFICIENT TO SUBSTANTIALLY REMOVE UNDESIRABLE GASEOUS CONSTITUENTS FROM THE GILSONITE AND STABILIZE THE SAME, CONTROLLING THE HEATING OPERATION TO AVOID COKING OF THE GILSONITE, PASSING THE HEATER EFFLUENT TO A DISTILLATION COLUMN, WITHDRAWING AN OVERHEAD PRODUCT FROM SAID DISTILLATION COLUMN COMPRISING THE UNDESIRABLE GASEOUS CONSTITUENTS AND LIQUID CARRIER, CONDENSING THE LIQUID CARRIER COMPONENT OF SAID OVERHEAD, SEPARATING CONDENSED LIQUID CARRIER AND THE UNCONDENSED GASEOUS

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