US3900041A

US3900041A - Modification of particle hardness in waxy crude oil slurries

Info

Publication number: US3900041A
Application number: US468969A
Authority: US
Inventors: Keith M Kersch; George A Pouska; Dennis E Drayer; Jr James E Tackett
Original assignee: Marathon Oil Co
Current assignee: Marathon Oil Co
Priority date: 1974-05-13
Filing date: 1974-05-13
Publication date: 1975-08-19
Anticipated expiration: 1992-08-19
Also published as: CH606389A5; AR206428A1; AU8102675A; FR2271500A1; BR7502885A; DE2521235A1; GB1499150A; DD119302A1; AT341950B; ATA353375A; IT1037979B; FR2271500B1

Abstract

Previously, waxy crude oils have been fractionated into a wax fraction and a liquid fraction; the wax fraction formed into particles and slurried into the liquid fraction for transportation in pipelines. Particle stability is enhanced by extruding molten wax without substantial crystalline structure into a hot wax immiscible fluid flowing cocurrent to the extruded wax and under conditions which will quickly form a smooth shell, and thereafter cooling to form hard, smooth spheres which resist mechanical degradation and which further approach a stabilized, or maximum, pressure drop at a slower rate than non-hardened particles. This treatment results in a particle which can be pumped in a pipeline at heavier particle loadings or with less pressure.

Description

United States Patent 1 1111 3,900,041

Kersch et al. Aug. 19, 1975 MODIFICATION OF PARTICLE HARDNESS IN WAXY CRUDE OIL SLURRIES Primary E.\'amI'nerAIan Cohan Attorney, Agent, or FirmJoseph C. Herring; Richard [75] Inventors. Kelth M. Kersch, George A. Pouska, C. Willson Jr; Jack L- Hummel Dennis E. Drayer; James E. Tackett, Jr., all of Littleton, Colo.

[57] ABSTRACT [73] Assignee: Marathon Company Findlay- Previously, waxy crude oils have been fractionated Ohm into a wax fraction and a liquid fraction; the wax frac- [22] Filed; May 3 974 tion formed into particles and slurried into the liquid fraction for transportation in pipelines. Particle stabil- [21] App! 468,969 ity is enhanced by extruding molten wax without substantial crystalline structure into a hot wax immiscible 52 us. c1. 137/13; 302/66; 264/9; fluid flowing Cocurrem to the extruded wax and under 20 370 conditions which will quickly form a smooth shell, and 51 CL 17 1 16; 3 5 53 30; o 43 02 thereafter cooling to form hard, smooth spheres which 58 Field of Search 137/1, 13; 264 5, 9; resist mechanical degradation and which further p- 5 302/66; 208/370, 14, 252/33 proach a stabilized, or maximum, pressure drop at a slower rate than non-hardened particles. This treat- 5 References Cited ment results in a particle which can be pumped in a UNITED STATES PATENTS pipeline at heavier particle loadings or with less pressure. 3,468,986 9/1969 Watanabe 264/9 3,804,752 4 1974 Merrill 137/13 2 Claims, 2 Drawing Figures LOW POUR POINT FRACTION DISTILLATION LD WATER P COLUMN 4 g, l\\ WAXY" CRUDE L I 1 BEADS AND WATER OUT SEPARATION HIGH POUR POINT FRACTION (Molten Stat.)

COLUMN BEADS SLURRIEU IN LOW POUR POINT FRACTION EFFLUENT SLURRY PUMP WATER PUMP Q HOT WATER in PIPELINE LOW POUR POINT FRACTION PATENTEU Mm 9 ms POINT FRACTTON BEADS AND WATER our SEPARATION EFFLUENT WATER HOT WATER FRACTION (Molten State) WAXY CRUDE HlGH POUR POINT I PROCESS FOR TRANSPORTATTON OF WAXY CRUDE OIL DISTILLATION COLD WATER COLUMN STABIIAL'IZED T CONSTANT SHEAR RATE CONSTANT TIME 0 lg- 2 STABILIZATION OF BEAD SLURRY vs PRILL SLURRY MODIFICATION OF PARTICLE HARDNESS IN WAXY CRUDE OIL SLURRIES BACKGROUND OF THE INVENTION 1. Field of the Invention.

Waxy hydrocarbons are fractionated into at least two fractions. The wax fraction is congealed and slurried in the fluid fraction prior to storage or transportation.

2. Description of the Prior Art.

Pumping waxy hydrocarbon mixtures at temperatures below the pour point is very difficult. Many methods have been tried to improve the pumpability of waxy crudes, e.g. heat transfer methods, chemical agents to improve fluidity of the mixture, pour point depressants, diluents, etc., but in general these methods have not been commercially acceptable. In addition, the oil has been dispersed in water to form a water-external emulsion and the combination pumped at temperatures below the pour point of the crude oil.

Patents representative of the art include:

Kells, U.S. Pat. No. 271,080: Wax is separated from crude oil by pumping the crude oil, e.g. in small streams of jets, into the bottom of a tank containing a brine at a temperature sufficiently low to congeal the wax which is recovered in the brine.

Oberfell, et al., U.S. Pat. No. 2,526,966: Viscous crude oils are transported by removing the light hydrocarbons, hydrogenating the residue, combining the hydrogenated product and the light hydrocarbons and transporting the mixture.

Scott, et al., U.S. Pat. No. 3,269,601: The pumpability of waxy crudes is improved by dissolving in the oil, at superatmospheric pressure and while above its pour point, gases such as N CO flue gas, and hydrocarbons containing 1-3 carbon atoms. The gas becomes associated in some way with wax crystals and prevents the precipitated wax from agglomerating to form strong wax structures.

Watanabe, U.S. Pat. No. 3,468,986: Teaches the formation of spherical particles of wax by melting the wax, then dispersing the spheres in water maintained at a temperature above the solidification temperature of the wax and thereafter cooling the dispersion to solidify the dispersed droplets. The particles can be coated with finely divided solids such as calcium carbonate, etc. Watanabe teaches that it is known in the art to disperse waxy particles by molding, prilling, spray drying, extruding, etc.

Titus, U.S. Pat. No. 3,527,692: Crushed oil shale is transported in a solvent such as crude oil, retorted shale oil, or fractions thereof.

Dorsey, U.S. Pat. No. 3,321,426, teaches the formation of freeflowing wax particles by agitating molten wax in water maintained at a temperature above the melting point of the wax and thereafter cooling the mixture and separating the congealed pellets of wax. The wax is sheared as it is extruded into the water.

Allibone et al., U.S. Pat. No. 3,234,122: Waxy crudes are transported by first precipitating the wax in the form of large crystals and thereafter transporting the crude oil containing the crystals. The crystals are formed, e.g., by heating the crude oil to 200F. and then cooling at 1F/min to 60F.

Scott, U.S. Pat. No. 3,292,647, teaches transportation of waxy crude oils in a pipeline by shearing the crude at a temperature below its pour point to break down the wax and form a fine dispersion, then introducing a gas, e.g. N CO and natural gas, with the sheared crude to prevent regrowth of the wax crystals and thereafter pumping the composition.

This technology, except for heat transfer systems, e.g. heat exchangers to heat the crude oil, and crude oil-water suspension systems, has generally proven to be commercially unattractive where the crude oil contains relatively large concentrations of wax.

U.S. Pat. No. 3,804,752 to Merrill, Jr. et a1 teaches transporting waxy crude oils by fractionating the crude into a high pour point fraction and a low pour point fraction, thereafter slurrying the congealed fraction in the low pour point fraction and pumping the slurry.

SUMMARY OF THE INVENTION Applicants have discovered an improved process of transporting waxy hydrocarbon mixtures at seasonably ambient temperatures by fractionating the hydrocarbon mixture into at least a relatively high pour point (wax) fraction and a relatively low pour point (liquid) fraction, introducing the wax fraction as droplets, at a temperature above its melting point, into a hot wax immiscible fluid flowing under laminar flow conditions and flowing cocurrent to the wax fraction, and then into a colder wax immiscible fluid to congeal the particles. Thereafter, the wax particles are separated from the wax immiscible fluid and combined with a liquid hydrocarbon and the resulting slurry transported, preferably in a pipeline.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a typical embodiment of the invention wherein the waxy crude oil enters a distillation column and is separated into a low pour point liquid fraction and a high pour point wax fraction. The molten wax fraction is extruded into the bottom and comes in contact with hot water introduced externally and concentric to the wax through the nozzle. Colder water enters at the top and at the bottom of the column. Water effluent exits at the bottom of the column. The extruded wax congeals into beads before it reaches the top of the column. The beads and some of the water flow out of the column into a separator and the beads are recovered. Thereafter, the beads are combined with the liquid fraction to obtain a transportable slurry.

FIG. 2 compares the rate of stabilization of two different slurn'es, one containing prills and the other beads.

DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention is used to transport waxy hydrocarbon mixtures having an average pour point above the ambient temperature of the transportation system. Waxy hydrocarbon mixtures are mixtures containing wax. Some asphaltenes can be tolerated. Wax is defined as the precipitate formed by dissolving one part of hydrocarbon mixture in ten parts of methyl ethyl ketone at about C. and cooling the mixture to 25C. Examples of waxy hydrocarbon mixtures include crude oils, shale oil, tar sand oil, fuel oil, gas oil and other waxy hydrocarbon mixtures and mixtures of two or more of the same type or different hydrocarbon mixtures. Waxy crude oils are particularly useful in this invention. Examples of average pour points of waxy hydrocarbon mixtures particularly useful with this invention include about 10 to about 200F., preferably about 0 to about 150F., and more preferably 75 to about 150F.

The hydrocarbon mixture is separated into at least two fractions, a liquid overheads fraction which has a relatively low pour point (referred to as the liquid fraction) and a wax bottoms fraction which has a relatively high pour point (referred to as the wax fraction). The wax fraction is about 1 to about 80% and preferably about 5 to about 70% and more preferably about 10 to about 60% by weight of the original hydrocarbon fraction. Fractions other than the mentioned fractions can be obtained and used for other purposes.

Fractionation can be by any process which separates the hydrocarbon mixture into high and low pour point fractions. Optionally, a part of the wax fraction can be cracked and/or hydrogenated during fractionation or before congelation.

The molten wax is preferably about to about 175F. and more preferably about 20 to about 150F. and most preferably about 50 to about 125F. above its melting point (as defined by inverse cooling curve in Characterization of Petroleum Waxes, S. W. Ferris, Chapter 1 of The Proceeding of the ASTM TAPPI Symposium on Petroleum Waxes, Feb. 18-21, 1963, Special Technical Association Publication, STAP, No. 2) as it is dispersed into the column. Also, it is preferred that the temperature of the molten wax be high enough that there is substantially no crystalline structure (including hydrocarbons other than wax) within the molten wax and that maximum durability or integrity of the resulting wax particles is obtained-see Example IV for working example of this preferred temperature range. If the wax fraction has not been cooled to a temperature below the above preferred temperature range since coming from the distillation column, it can be introduced into the column and still obtain durable wax particles.

Cooling The molten wax is cooled in two stages. First, the wax is dispersed into a hot wax immiscible fluid (coolant) at a temperature which relatively slowly cools the wax to form smooth, substantially round, preferably spherical, shells around the dispersed wax particles. Then, the particles are passed into a colder coolant to substantially complete the solidification of the particles.

The coolant should have a temperature above the pour point of the wax, but below the wax temperature' Preferably the coolant is at least about 5 to about 150F. and preferably about to about 10F. and more preferably about to about 80F. below the molten wax temperature as it is dispersed into the column. Examples of useful temperature include at least 140F. and preferably about 180F. when the coolant is water. The wax composition and equipment design will control the amount of temperature differential between the molten wax and the coolant. If the coolant is too cold, the extruding wax will be filamentary and if the temperature is too hot, the flow path required to form the spherical shell will be excessive. Agglomeration indicates too little cooling and dimpling indicates excessive coolant-to-wax temperature differential (i.e. differential cooling temperature change is too sudden and too large).

Superior results are obtained through the use of sub stantially concentrically arranged nozzles wherein the wax is injected or extruded into the coolant through a central orifice preferably about 0.030 inch to about 0.5

inch and more preferably about 0.050 inch to about 0.100 inch in diameter. The coolant can be introduced through an annular nozzle so that it flows cocurrent and concentric to the wax. The velocity of the wax and coolant is preferably the same and more preferably is within the laminar flow region. Different flow rates can cause turbulence, reduce the size and roughen the surface of the sphere. Single hole nozzles are useful and with this type of nozzle the coolant can flow concentric and cocurrent to the wax by thermal convection currents.

The cooled wax particles should have an average diameter of about 0.05 or less to about 20 or more mm. and preferably about 0.1 to about 10 mm. and more preferably about 1 to about 8 mm. The particles are preferably spherical, but can be elongated and can be of either substantially uniform or random diameter sizes. The physical shape and size is affected by the temperature and flow rate of the hot coolant and the molten wax and by introducing the coolant concentric to the nozzle(s).

The wax particles then come in contact with a colder wax immiscible fluid (colder coolant) to obtain a substantially solidified particle. The colder Coolant can be about ambient temperature and is preferably about 3 to about F. below the solidification temperature of the wax. The particles follow a sufficiently long flow path to substantially solidify the wax droplets. ltis preferred that the temperature differential between the inlet cold coolant and the outlet fluid in the column be large enough to obtain maximum utilization of the enthalpy of the liquid.

Temperature change from the hot coolant to the colder coolant can be controlled by introducing the coolants at one or more places within the tower and by regulating either heat input or output in the column by heat exchangers, etc. The temperature change can be a gradual change or a combination of a gradual change in the bottom of the column and an abrupt. change in the top of the column, or any desired modification thereof. However, it is necessary that the temperature change be sufficient to cool the average temperature of the wax particles to a temperature below the average pour point of the wax or that the transportation system be at a sufficiently low temperature to complete solidification of the particles.

The coolant and/or the colder coolant can be any fluid that is substantially immiscible with the wax at the extruding or dispersing temperature. Examples include alcohols, ketones, esters, and other polar or semipolar organic compounds. Preferably, the coolants are water. Also, it can be a combination of two or more coolants.

solidification, as used herein, includes congealing, crystalization and making into a consistency like jelly. Preferably the solidified particle has at least a hard veneer on the wax particle. The interior of the particle can be fluid, but is preferably substantially solid.

A surfactant can be incorporated into the molten wax. Volume amounts of 0.001 to about 20% and preferably about 0.01 to about 10% and more preferably about 0.1 to about 1%, by volume based on the fraction, are useful. Examples of useful surfactants include fatty acids, e.g. containing about 10 to about 20 carbon atoms and preferably the monovalent cationcontaining salts thereof. Sorbitan monolaurate is an example of a useful surfactant. Preferably the surfactant is a petroleum sulfonate and more preferably one conetc.

In a preferred embodiment, the liquid fraction or a liquid hydrocarbon is introduced into the top of the column to physically remove the wax particles. In this case, an interface between the coolant and the liquid hydrocarbon is maintained at a point below the elevation in the column at which the particles are removed. The particles tend to accumulate at the interface.

Slurry Preparation The liquid hydrocarbon (this term is defined to include the liquid fraction) should be at least about 5 and more preferably at least about 30 and most preferably at least about 70F. below the solution temperature of the solidified wax particles when the liquid hydrocarbon is slurried with the particles. Solution temperature is defined as that temperature at which a major portion of the particles are in solution of the liquid hydrocarbon.

During the slurrying operation, the temperature of the liquid hydrocarbon is such that the resulting slurry temperature is preferably about 5 to about 10F. above and more preferably to about F. above the minimum seasonably ambient temperature of the transportation system. Also, it is preferred that the temperature of the liquid hydrocarbon during slurrying is about 30F. and more preferably about 70F. below the solu-.

tion temperature of the particles in the fraction.

The usual techniques and equipment for slurrying solids in liquids are useful in our process. However, the liquid hydrocarbon should be at least about 5 and more preferably at least about 30 and most preferably at least about 70F. below the solution temperature of the particles in the liquid hydrocarbon and have a pour point at least 1 and preferably at least 5F. and more preferably at least about 15F. below the average temperature of the transportation system.

Also, it is preferred that the temperature of the liquid hydrocarbon be low enough during the slurrying operation to provide a slurry temperature preferably about F. below to about 10F. above and more preferably at about the minimum seasonably ambient temperature of the transportation system.

A liquid and/or gaseous diluent such as straight run gasoline, reservoir condensate or light hydrocarbon can be admixed with the liquid hydrocarbon before, during or after the slurrying operation. Any diluent is useful as long as it is miscible with the liquid hydrocarbon, has a pour point below the minimum temperature of the transportation system and does not readily solubilize the wax particles or cause any reaction to substantially increase the solubility of the wax particles in the liquid hydrocarbon. Crude oils can be used as the diluent, but preferably the crude oil has a wax concentration less than about l0%-the wax can be in crystalline form. Where a gaseous diluent is used, it is preferred that it be dissolved in the slurry at transportation condition to prevent cavitation of pumps.

Concentrationof the wax particles in the slurry is preferably about 1 to about 60% or more and preferably about 5 to about 55% and most preferably about 20 to about 45% by weight.

Transportation of the Slurry The temperature of the slurry during transportation is preferably below the solution temperature of the wax particles at all times. The slurry can stand temperatures higher than the solution temperature of the wax for short periods of time so long as substantial amounts of the wax particles are not reliquefied. But if the temperature does exceed the solution temperature, the slurry can still be effectively transported in a pipeline as long as the temperature does not cycle more than preferably about 3SF. below the highest temperature reached by the slurry during transportation. Also, as long as the temperature is increasing during the pipelining, even above the solution temperature, there is no detrimental effect. However, when the temperature decreases to more than about 10F below the highest transportation temperature, then large pressure drops occur if the particle solution has been substantial.

Transportation system, as used herein, includes tanks, tank trucks, tank trailers, tank barges, ships or tankers, pipelines, pipelines and tank batteries, or holding tanks and combinations thereof. Preferably the transportation system is a pipeline or a pipeline plus tanks.

The slurry can be transported under laminar flow, transitional flow (e.g. Reynolds Nos. about 2000 to about 4000) or turbulent flow conditions in the conduit. It is preferably transported under laminar and transitional flow conditionsturbulency within the pipeline tends to break apart and solubilize the wax particles in the liquid hydrocarbon of the slurry.

The slurry is preferably transported in a conduit wherein the average maximum temperature of the conduit is below the average solution temperature of the wax particle in the liquid hydrocarbon.

In addition, the average temperature of the conduit is desirably not below the average pour point of the liquid hydrocarbon and preferably is at least about 20F. and more preferably at least about 25F. above this pour point.

A gas soluble in the liquid hydrocarbon can be added to the slurry to facilitate pumpability. Examples of gases include CO hydrocarbons containing less than about 3 carbon atoms, N flue gases and like gases. Preferably the gas is immiscible with the wax particles.

The wax particles can also be coated with solid materials or other agents to inhibit agglomeration and to permit higher slurry transportation temperatures.

EXAMPLES The following examples are presented to teach working embodiments of the invention. Unless otherwise specified, the percents are based on weight.

EXAMPLE I A waxy crude oil (having an average pour point 1 15F.) is distilled into a liquid fraction (average pour point 17F.) and a wax fraction (average pour point F., melting point F.). The wax fraction is stored at ambient temperature and thereafter is heated 7 to and maintained at 200F. for at least 2 hours; it is then fed at a rate of 300 lbs/hrinto a manifoldcontaining 37 nozzles positioned in the bottom of-an 8 in. dia. X 7 feet water column. The nozzles are" spaced /2 inch apart. Each nozzle is 1.375 inches long with a 0.08 inch diameter hole drilled lengthwise 1.275 inches deep. Wax is fed into the side of the nozzle from the manifold. Hot water is flowed cocurrent to the wax and concentric to the nozzles at a rate of 0.75 gal/min and at an initial temperature of 180F. Cold water at 45F. is introduced peripherally into the top of the column and flows to the bottom of the column by free convection.

Water may be drawn off the bottom of the column if additional cooling is needed. The cocurrent water and beads exiting the top of the column have an average temperature of 80F. The average diameter of the congealed beads is about 3/16 inch. A slurry is obtained by stirring sufficient amounts of the beads into a holding tank with the liquid fraction to obtain a bead concentration of 27.5%. The slurry is then pumped through a 6 inches diameter pipeline at 38F. without difficulty.

EXAMPLE I] The wax of Example I that has been stored at ambient temperature is prilled by introducing molten wax through 19 nozzles (inside diameter 0.035 inch) at 200F. and at a rate of 190 lbs/hr into a prilling tower. The prills fall approximately 25 feet through a 2 foot inside diameter prilling tower and are cooled with a fine mist of water. The prills are collected at the bottom of the prilling tower and separated from the water. Thereafter, a slurry is obtained by combining the prills with the liquid fraction from Example I at a concentration of 27.5%.

EXAMPLE III Comparative Test of Beads vs. Prill A slurry containing the liquid fraction of Example I and 27.5% of the beads of Example I and the slurry of Example II are tested for percent disintegration of the wax particles for periods of two and 3 hours by agitating the slurry at 40F. with an impeller rotating at 650 rpm. The percent solids left in the slurry after each test is determined by separating the solids from the slurry by elutriation using acetone as the carrier fluid. The solids which are not significantly changed after the disintegration tests are separated from the slurry and weighed. Table 1 indicates results of the test:

TABLE 1 Disintegration 7r Disintegration after agitation after agitation Sample (Two Hours) (Three Hours) Slurry l (Beads) 74 82 Slurry 2 (Prills) 89 92 EXAMPLE IV TABLE 2 7c Disintegration after agitation (Three Hours) 7: Disintegration after agitation Sample (Two Hours) ,Slurry containing beads obtained from Example IV 44. 6]

EXAMPLE V A slurry containing 27.5% of the prills of Example ll and a slurry containing 27.5% of the beads of Example 1 are tested for stabilizationthe hydrocarbon phase in both slurries is the liquid fraction of Example I. Stabilization is defined as the transfer of ,material between solid and liquid phases until equilibrium is attained. As stabilization progresses, the appearance and apparent viscosity of the slurry change. Stabilization is measured by the pressure drop per unit pipe length as a function of time at constant shear rate and slurry temperature. When stabilized, no further change in pressure drop occurs. It is found that the stabilization rates as indicated by a plot of AP/L vs. Time for the bead slurry is less than the prill slurry. FIG. 2 illustrates the data obtained by this example. These data are obtained in a pipeline having an inside diameter of 2 inches and a length of feet and the slurriesare run therethrough at the same temperature. These data show that the prill slurry and the bead slurry stabilize to the same pressure drop, but that the bead slurry stabilizes at a slower rate than does the prill slurry. This is significant in terms of slurry pumping horsepower requirement. 1

It is intended that all equivalents obvious to those skilled in the art be incorporated within the scope of the invention defined within the specification and appended claims.

We claim:

1. In a process for transporting waxy petroleum crudes by fractionating the crude into at least a wax fraction and a liquid fraction, forming substantially round particles of wax, slurrying the wax particles in a liquid hydrocarbon comprised of the liquid fraction and transporting the slurry, the steps comprising introducing molten wax having no substantial crystalline structure into a hot, wax immiscible fluid flowing cocurrent to the introduction of the molten wax and at flow rates sufficient to form substantially round particles having a substantially smooth outer shell and thereafter introducing the wax particles into a colder wax immiscible fluid at a sufficiently low temperature to substantially solidify the wax particles.

2. The process of claim 1 wherein the immiscible fluids are water.

3. The process of claim 1 wherein the liquid hydrocarbon is the liquid fraction.

4. The process of claim 1 wherein the temperature of the molten wax as it is introduced into the hot, wax immiscible fiuid is about0 to about F. above its melting point. g

5. The process of claim 1 wherein the temperature of the molten wax is about 20 to about 150F. above its melting point. I i

6. The process of claim 1 wherein the temperature of the molten wax is about 50 to about 125F. above its melting point.

7. The process of claim 1 wherein the hot, wax immiscible fluid is at least about 5 to about 150F. below the temperature of the molten wax as the latter is dispersed therein.

8. The process of claim 1 wherein the hot, wax immiscible fluid is at least about to about 80 below the temperature of the molten wax as the latter is dispersed therein.

9. The process of claim 1 wherein in the temperature of the hot, wax immiscible fluid is at least about 140F.

10. The process of claim 1 wherein the molten wax is under laminar flow as it comes in contact with the hot, wax immiscible fluid.

11. The process of claim 1 wherein the hot, wax immiscible fluid flowing cocurrent to the molten wax is under laminar flow.

12. The process of claim .1 wherein the concentration of the solidified wax particles in the liquid hydrocarbon is within the range of about 1 to about 60%.

13. The process of claim 1 wherein the concentration of solidified wax particles in the liquid hydrocarbon is within the range of about 20 to about 45% by weight.

14. The process of claim 1 wherein at least a major portion of the wax particles is substantially solidified.

15. The process of claim 1 wherein the waxy hydrocarbon mixture has an average pour point within the range of about 75 to about 150F.

16. The process of claim 1 wherein the molten wax, before it comes in contact with the hot, wax immiscible fluid, is heated to a temperature sufficient to remove substantially all crystalline structure in the molten wax and to obtain maximum durability of the wax particles in the slurry.

17. The process of claim 1 wherein a diluent miscible with the liquid hydrocarbon is admixed with the slurry to facilitate transportation.

18. The process of claim 17 wherein the diluent is a liquid crude oil containing less than 10% wax.

19. in a process for transporting waxy petroleum crudes having an average pour point of about to about l50F. by fractionating the crude into at least a wax fraction and a liquid fraction, forming substantially round particles of wax, slurrying the particles in the liquid fraction and transporting the slurry, the steps comprising introducing molten wax fraction at a temperature of about 20 to about 150F. above its melting point into hot water flowing cocurrent to the introduction of the molten wax fraction and at flow rates sufficient to form substantially round particles having a substantially smooth outer shell and thereafter introducing the wax particles into a colder water at a sufficiently low temperature to substantially solidify the wax particles.

20. The process of claim 19 wherein the molten wax fraction is about 50 to about F. above its melting point.

21. The process of claim 19 wherein the hot water is at least about 20 to about 80F. below the temperature of the wax fraction as the latter is dispersed therein.

22. The process of claim 19 wherein the temperature of the hot water is at least about F.

23. The process of claim 19 wherein the molten wax fraction is under laminar flow as it is introduced into the hot water.

24. The process of claim 19 wherein the hot water flowing cocurrent to the molten wax fraction is under laminar flow.

25. The process of claim 19 wherein the concentration of solidified wax particles in the liquid fraction is within the range of about 20 to about 45% by weight.

26. The process of claim 19 wherein a liquid crude oil containing less than 10% wax is admixed with the slurry to facilitate transportation.

Claims

1. IN A PROCESS FOR TRANSPORTING WAXY PETROLEUM CRUDES BY FRACTIONATING THE CRUDE INTO AT LEAST A WAX FRACTION AND A LIQUID FRACTION FORMING SUBSTANTIALLY ROUND PARTICLES OF WAX SLURRYING THE WAX PARTICLES IN A LIQUID HYDROCARBON COMPRISED OF THE LIQUID FRACTION AND TRANSPORTING THE SLURRY THE STEPS COMPRISING INTRODUCING MOLTEN WAX HAVING NO SUBSTANTIAL CRYSTALLINE STRUCTURE INTO A HOT WAX IMMISCIBLE FLUID FLOWING COCURRENT TO THE INTRODUCTION OF THE MOLTEN WAX AND AT FLOW RATES SUFFICIENT TO FORM SUBSTANTIALLY ROUND PARTICLES HAVING A SUBSTANTIALLY SMOOTH OUTER SHELL AND THEREAFTER INTRODUCING THE WAX PARTICLES INTO A COLDER WAX IMMISCIBLE FLUID AT A SUFFICIENTLY LOW TEMPERATURE TO SUBSTANTIALLY SOLIDIFY THE WAX PARTICLES.

2. The process of claim 1 wherein the immiscible fluids are water.

4. The process of claim 1 wherein the temperature of the molten wax as it is introduced into the hot, wax immiscible fluid is about 0* to about 175*F. above its melting point.

5. The process of claim 1 wherein the temperature of the molten wax is about 20* to about 150*F. above its melting point.

6. The process of claim 1 wherein the temperature of the molten wax is about 50* to about 125*F. above its melting point.

7. The process of claim 1 wherein the hot, wax immiscible fluid is at least about 5* to about 150*F. below the temperature of the molten wax as the latter is dispersed therein.

8. The process of claim 1 wherein the hot, wax immiscible fluid is at least about 20* to about 80* below the temperature of the molten wax as the latter is dispersed therein.

9. The process of claim 1 wherein in the temperature of the hot, wax immiscible fluid is at least about 140*F.

12. The process of claim 1 wherein the concentration of the solidified wax particles in the liquid hydrocarbon is within the range of about 1 to about 60%.

15. The process of claim 1 wherein the waxy hydrocarbon mixture has an average pour point within the range of about 75* to about 150*F.

19. In a process for transporting waxy petroleum crudes having an average pour point of about 75* to about 150*F. by fractionating the crude into at least a wax fraction and a liquid fraction, forming substantially round particles of wax, slurrying the particles in the liquid fraction and transporting the slurry, the steps comprising introducing molten wax fraction at a temperature of about 20* to about 150*F. above its melting point into hot water flowing cocurrent to the introduction of the molten wax fraction and at flow rates sufficient to form substantially round particles having a substantially smooth outer shell and thereafter introducing the wax particles into a colder water at a sufficiently low temperature to substantially solidify the wax particles.

20. The process of claim 19 wherein the molten wax fraction is about 50* to about 125*F. above its melting point.

21. The process of claim 19 wherein the hot water is at least about 20* to about 80*F. Below the temperature of the wax fraction as the latter is dispersed therein.

22. The process of claim 19 wherein the temperature of the hot water is at least about 140*F.