AU7321781A

AU7321781A - Fluid fuels containing carbonaceous materials and process of making

Info

Publication number: AU7321781A
Application number: AU73217/81A
Authority: AU
Inventors: Joseph T. Brennan
Original assignee: Diamond Shamrock Corp
Current assignee: Diamond Shamrock Chemicals Co
Priority date: 1981-04-02
Filing date: 1981-04-02
Publication date: 1982-10-19
Also published as: EP0074949A4; IT8248136A0; ZA822262B; EP0074949A1; IT1237325B; BR8108995A; BE892729A; PL235753A1; WO1982003400A1; JPS58500483A

Description

FLUID FUELS CONTAINING CARBONACEOUS MATERIALS AND PROCESS OF MAKING

BACKGROUND OF THE INVENTION

This invention relates to stabilized oil slurries and stabilized water slurries of particulate carbonaceous material and more particularly to stabilized oil slurries and stabilized water slurries of ground coal or coke having a specific size distribution characteristic and a method of making these slurries. Addition of solid particulate carbonaceous material, such as coal or coke, to liquid hydrocarbon fuel, such as fuel oil, has been studied for a number of years. In the past few years, and particularly during the last two years, the importance of reducing dependency of the world upon natural gas and liquid hydrocarbon fuels for its energy has been dramatically demonstrated.

Though not providing a complete solution to this energy problem, attempts have been made to incorporate solid particulate carbonaceous material, such as coal and coke, in liquid hydrocarbon fuels, because these particulate carbonaceous materials are far more plentiful than liquid fuels. There is considerable interest in extending and/or supplementing liquid fuels with solid fuels. Likewise, the transportation of solid carbonaceous material has been studied to see if utilization of in-place pipe line systems could be used for the transportation of these types of fuel materials. An example of this type of transportation would be the pipe line transportation of solid particular carbonaceous material, such as coal or coke, made into an aqueous slurry. Many large industrial fuel users have equipment which was designed and constructed for the transportation, storage and combustion of liquid fuels. As yet, solid/ liquid slurries, suspensions or emulsions are not accepted for regular use in such conventional equipment. In some instances this equipment was converted from its original design for burning, solid fuels to a design capabl of burning liquid fuels. Many believe this trend should be reversed, while at the same time, allowing for the continued use of the present pipe line systems put in place to supply these liquid fuel burning systems.

Various solutions to the problem of combining a solid particulate carbonaceous material with a liquid have been explored. One solution involved the grinding carbonaceous material to colloidal size before introducing it into a liquid. Even though this solution was successful, grinding costs were prohibitive. Coal oil slurries also tend to form gels when heated to useable temperatures during storage, usually thixotropic gels. Attempts were made to use the gelling phenomenon of coal oil slurries to hold larger than colloidal size particles in suspension. The gel was later broken down by adding additional oil so that the resulting, slurry was pumpable without particulate material settling out. Inherently, this procedure was an expensive batch process.

Various materials were also added in an attempt to stabilize a coal oil slurry against settling of larger than colloidal size coal particles. Lime-rosin and starch were added to prevent settling of the larger slurry particles. Casein gelatin and rubber were also added as suspension stabilizing agents to inhibit settling of coal particles. It was found that these suspension stabilizing agents must be added in quantities which undesirably thickened and increased the viscosity of the slurry in order to prevent substantial quantities of the coal particulate material from settling. Increasing slurry viscosity not only reduced the settling problem, but also limited uses to which the slurry might be put.

European Patent Application No. 79302880.4 Publication No. 0012606 of Veal, published June 24, 1980, describes a carbonaceous oil slurry containing from

15-55% by weight of a solvent refined coal (SRC) dispersed in an oil prepared by grinding the coal in the oil medium in the absence of free oxygen to a particle size having a range of 1-10 microns. The application teaches that the stability of the disclosed coal/oil dispersions is a function of three variables; 1) the method of grinding in the presence of oil; 2) the final particle size; and, 3) the final concentration of the solvent refined coal in the oil. It also teaches that if correctly chosen these parameters produce a gel which is the desired form of the end product. The preferred percentage of coal in the final product is 30-40% by weight.

British Patent 1,548,402 of Eric John Clayfield, et al, issued July 11, 1979 describes a method of making a fluid fuel composed of liquid hydrocarbon finely divided coal particles and water as a stabilizing agent. The process incorporates combining up to 30% by weight coal with a grain size of up to 6 mm with water and mixing this material with liquid hydrocarbon fuel so as to have no more than 50 weight percent coal in the mixture and grinding this mixture until the coal particle size is 500 microns or less. It is further stated that it is critical that the coal be wetted with water before any oil is added or in an inordinate amount of settling will occur. British Patent 1,523,193 issued August 31, 1978, to Roger John Russell Kairns describes a process for making a coal/oil mixture containing 50 to 55 weight percent coal based on the total weight of dispersion in oil which has been ground to have a particle size of less than 10 microns. In addition the coal used as a starting material is preferably supplied having a particle size less than 250 microns. Again, as in the previous art cited, this patent teaches that very small particle size is necessary in order for the coal/oil mixture to be stable.

SUMMARY OF THE INVENTION

It has now been found that carbonaceous liquid hydrocarbon slurries and carbonaceous aqueous slurries superior to those previously known in the art are possible utilizing a specific particulate size distribution. Broadly stated the instant invention relates to carbonaceous liquid hydrocarbon slurries of low viscosity and having enhanced physical stability comprising; an intimate mixture of a liquid hydrocarbon; a stabilizing agent; and, a particulate carbonaceous material; wherein said particulate carbonaceous material contains at least 25%, by weight, based on the total particulate carbonaceous material weight, of particles that are more coarse than 75 microns. This invention also relates broadly to a carbonaceous aqueous slurries of low viscosity and enhanced physical stability comprising; an intimate mixture of water, a stabilizing agent; and a particulate carbonaceous material; wherein said particulate carbonaceous material contains at least 25%, by weight, based on the total particulate carbonaceous material weight, of particles that are more coarse than 75 microns.

A method of preparing the carbonaceous liquid hydrocarbon slurries and the carbonaceous aqueous slurries of low viscosity and enhanced physical stability, may be stated broadly as the process of comprising; a) establishing an intimate fluid mixture comprising; a liquid hydrocarbon or water, a stabilizing agent, and a particulate carbonaceous material; b) introducing at elevated pressure said intimate mixture of (a) into a colloid mill; c) grinding said intimate mixture of (a) in said colloid mill under elevated pressure; and d) withdrawing the resultant ground carbonaceous liquid hydrocarbon slurry from said mill.

A second method of preparing these carbonaceous liquid hydrocarbon slurries and the car bonaceous aqueous slurries of low viscosity and enhanced physical stability may be stated broadly as the process comprising; a) introducing a liquid hydrocarbon or water, a stabilizing agent, and a particulate carbonaceous material, by separate feed lines, under elevated pressure, on each feed line, .thereby establishing an intimate mixture in a colloid mill; b) grinding said intimate mixture of (a) at elevated pressure in said colloid mill; and c) withdrawing the resultant ground carbonaceous liquid hydrocarbon slurry.

Alternatively, either of the above-described processes may be modified to allow for the batch or continuous addition of an additional amount of particulate carbonaceous material broadly described as, for example, comprising; a) establishing an intimate fluid mixture comprising; a liquid hydrocarbon, a stabilizing agent and a particulate carbonaceous material; b) introducing at elevated pressure said intimate mixture of (a) into a colloid mill; c) grinding said intimate mixture of (a) in said colloid mill under elevated pressure; d) withdrawing the resultant ground carbonaceous liquid hydrocarbon slurry; e) adding to said ground slurry of (d) from an outside source, from one to forty percent, by weight, based on the total slurry weight, of a particulate carbonaceous material having particles that are more coarse than 75 microns.

Alternatively, this modified process may be broadly stated as comprising; a) introducing water, a stabilizing agent, and a particulate carbonaceous material by separate feed lines, under elevated pressure on each feed line, thereby establishing an intimate mixture in a colloid mill; b) grinding said intimate mixture of (a) at elevated pressure in said colloid mill; c) withdrawing the resultant ground carbonaceous aqueous slurry; d) adding to said ground slurry from 1-40%,. by weight, based on the total slurry weight of a particulate carbonaceous material having particles that are more coarse than 75 microns.

DETAILED DESCRIPTION

LIQUID HYDROCARBON

Liquid hydrocarbons suitable for use in the carbonaceous liquid hydrocarbon slurries include fuel oils such as #6 fuel oil, #1 fuel oil, bunker C fuel oil, #2 fuel oil, gas oils, crude oils, kerosene and mixtures thereof. For efficiency and economy it is advantageous to use fuel oil and the preferred liquid hydrocarbon is low sulfur #6 fuel oil having a SSF viscosity of from 80 to 100 seconds. "SSF" as used herein refers to Saybolt Second Furol. The liquid hydrocarbons are used in amounts of from 9.9 to 89 percent by weight based on the total carbonaceous liquid hydrocarbon slurry weight. While the described slurries can contain high percentages of liquid hydrocarbon, e.g., up to 89 weight percent, the systems will more typically contain liquid hydrocarbon in amounts ranging from 10 to 50 percent, and with amounts ranging from 10 to about 40 weight percent being preferred for economy. It is understood that the liquid hydrocarbon used in any particular formu lation may in fact be a mixture of one or more liquid hydrocarbons as described above or may be a particular fraction of a catalytically cracked crude petroleum product.

STABILIZING AGENT

The term "stabilizing agent" as used herein, encompasses surfactants, thickeners and mixtures thereof. The stabilizing agent is used to augment the physical stability of the particulate carbonaceous material in either the liquid hydrocarbon or water. Generally, stabilizing agent in an amount of as little as 0.1 weight percent, based on the total slurry weight, will be used, although the use of lesser amounts is contemplated. For the carbonaceous liquid hydrocarbon slurries, as well as for the aqueous slurries, an amount of up to 5 weight percent, basis total slurry weight, may be useful. Typically, for economy plus augmented physical stability, the liquid hydrocarbon slurries will contain from about 0.2 to about 2 weight percent of stabilizing agent while the aqueous slurries will contain from about 0.2 to S weight percent of such agent. Useful amounts, as well as an explanation of desirable, i.e., desirably physically stable, "stable dispersions" will be discussed hereinbelow. By the term "surfactants" as such is used herein is meant additive chemicals having diverse action such as wetting agents, spreaders, penetrants, dis- persants, emulsifiers, etc. A comprehensive list of specific surfactants can be found in "McCutcheon's, Detergents and Emulsifiers", North American Edition, 1980. Exemplary suitable surfactant's include a sodium salt of a condensed mono naphthalene sulfonic acid, dioctal ester of sodium sulfosuccinic acid, and salts of nitrogen containing base reacted with alkylnaphthalenesulfonic acid. Examples of these last materials are monoalkylnaphthalenesulfonic acids, dialkylnaphthalenesulfonic acids and polyalkylnaphthalenesulfonic acids, typically prepared by neutralizing the sulfonic acid with a nitrogen containing base such as ammonia, monoethanolamine, monoethylamine or the like. Also suitable for use as a stabilizing agent are those surfactants commonly referred to as imidazoline quaternary salts. Particularly preferred for efficient slurry stability is the imidazoline quaternary salt produced from the reaction of oleic acid, aminoethylethanolamine and diethyl sulfate.

Thickeners may also be used alone, or in combination, and also in combination with the above-identified materials as the stabilizing agent. Suitable thickeners for use in the instant invention include, for example, ammonium alginate polysaccaride gum, amine salt of sodium cellulose sulfate and guar gum. Preferably, for economy the thickener is ammonium alginate.

It is further understood that mixtures of the above materials may be used as the stabilizing agent in the present invention. It is further understood that in some cases it is desirable and preferred to have mixtures which include for -example wetting agents and emulsifiers or other combinations thereof.

PARTICULATE CARBONACEOUS MATERIAL

The term "carbonaceous", as used herein, encompasses solid carbonaceous fossil fuel materials. Useful carbonaceous fossil fuel materials include bituminous coal, brown coal, anthracite coal, coke, petroleum coke, lignite, charcoal, peat and- mixtures thereof and the like. Particularly preferred for economy are bituminous coal, anthracite coal, brown coal, coke and petroleum coke.

At least 25 weight percent of the particulate carbonaceous material should have particle size more coarse than 75 microns and advantageously, for preparation of slurries of desirably low viscosity, about 30 weight percent or more of the particles are more coarse than 75 microns. Typically, the particles more coarse than 75 microns will be of sizes distributed within the range of from 75 microns up to about 3000 microns, although particles of size more coarse than 3000 microns are possible. Advantageously, for slurries of enhanced stability, the slurry will contain particles wherein at least 25 weight percent, and preferably at least 30 weight percent, will be of sizes distributed within the range of from 75 microns to about 1400 microns. Although slurries containing all particles more coarse than 75 microns are contemplated, it will be typical for particles more finely-divided than 75 microns to be present in the slurry, generally being found during slurry preparation. Although slurries with up to about 95 weight percent of particles falling within the 75 micron to 3000 micron size range can be useful, slurries with up to about 95 weight percent of particles within the 75-1400 micron size range are particularly desirable for enhanced slurry stability. Preferably, for economy the slurry will contain from about- 30 weight percent to about 75 weight percent of particulate carbonaceous material in the 75-1400 micron size range. For any of the foregoing slurries, the balance of the particles, will typically be more finely-divided than 75 microns. Such particles, or "fines" are usually produced in the production of the slurry. In slurries where the particle size distribution falls largely in the 75-3000 micron size range, almost all remaining particles, e.g., usually 75 percent to 99 percent, weight basis, of the balance of the particles will be more finely divided than 75 microns. It will be understood that the same proponderance of fines for the balance of particles can also be present when the particles are largely distributed in the 75-1400 micron size range; however, for these slurries it can often be the case that much of the balance of particles are more coarse, i.e., nearly 50% of the balance are more coarse, than 1400 microns. In typical slurry preparation, e.g., with particulate carbonaceous material having greater than 30 weight percent of particles in the 75-1400 micron size range, and using a bituminous coal for such material and a fuel oil characterized as having a viscosity of 80 to 100 SSF at 122 °F being used as the liquid hydrocarbon, the slurry produced can have viscosity of less than 5,000 cPs. This will be less than 5,000 centiposes as measured at 122°F on a Brookfield Model RVT viscosimeter at 0.3 revolutions per minute. Further, such low viscosity can be the case for carbonaceous liquid hydrocarbon slurries that contain 50 percent or more loadings, i.e., that contain 50 weight percent or more of particulate material. At 60 weight percent or more loading, with bituminous coal and the aforedescribed fuel oil, slurries can be prepared that have viscosities of thess than 10,000 centiposes, measured in the same manner.

It will be understood that the slurries of the present invention may additionally contain a variety, or combination, of further components and additives, e.g., those usually found in this art, such as fuel oil flow control agent, fuel supplements, including the lower alkanols, and agents to affect burn characteristics. Generally, these additional ingredients will be present in the aggregate in minor amount, e.g., about 5 weight percent or less basis total slurry weight, and more typically will be present in an amount for, such additives collectively, of on the order of only 1 to 2 weight percent, basis total slurry weight.

PREPARATION

The production of a carbonaceous liquid hydrocarbon slurry comprising; a) establishing a fluid mixture comprising; a liquid hydrocarbon, a stabilizing agent, and a particulate carbonaceous material; b) introducing at elevated pressure said mixture of (a) into a colloid mill; c) grinding said mixture of (a) in said colloid mill under elevated pressure; and, d) withdrawing the resultant ground carbonaceous liquid hydrocarbon slurry from said mill. Alternatively, the initial mixture of liquid hydrocarbon, stabilizing agent and particulate carbonaceous material may occur simultaneously with the introduction of said materials into the colloid mill by introducing these materials via separate feed lines directly into the colloid mill. It is understood that the oil and stabilizing agent may for example be pre- mixed and fed in a single feed line with the carbonaceous particulate material being fed in through a second feed line. Also, it is understood that the liquid hydrocarbon may be fed in through a single feed line while the coal premixed with the stabilizing agent can be fed in combination through a single feed line. Preferably, at least 25%, by weight, of the particulate carbonaceous material has a particle size of greater than 75 microns. The method of producing this particulate size to allow using the carbonaceous material in this process is not critical. Thus, grinding coal for example in a roller cage mill is acceptable as is for example grinding coke or coal in a roller ball mill, for example. It is understood that while, generally, the particle size distribution of the particular carbonaceous material introduced into the mix before grinding in the colloid mill is not critical it is important that substantially 90% of the material has a particle size distribution of from greater than 75 microns. It will be appreciated that as loadings of 70 weight percent of particulate carbonaceous material are mixed with the liquid hydrocarbon and stabilizing agent, the mixture can become too viscous to pass through the colloid mill. In these instances auxiliary heating can be used to provide enough heat to help provide the lower viscosity necessary for passage through the colloid mill. It is appreciated, however, that once through the colloid mill auxiliary heating is no longer needed as the novel particle size distribution of the process creates a carbonaceous liquid hydrocarbon slurry having a viscosity generally lower than comparably loaded carbonaceous liquid hydrocarbon slurries of the prior art thereby allowing higher loadings without causing problems of pumping, storage and use.

The colloid mill is a type of grinding apparatus utilizing a rotor and stator to perform the grinding function. The gap between the rotor and the stator determines the final size of the largest particles. Thus, eliminating the problem of oversize particles that plague other types of wet grinding techniques, such as, for example, wet grinding with a ball mill. Colloid mills suitable for use were available from Premier Mill Corporation of New York, New York, U.S.A. and described more fully in Premier Mill Corporation Sales Bulletin #CM-5/77, for example. The materials in the initial mixture are moved from the mixing area into and through the colloid mill by use of elevated pressures. These elevated pressures range from atmospheric to approximately 50 psi. By "atmospheric" is meant that gravity feed is a viable method of moving the mixture through the colloid mill. Presently, preferred pressure ranges are from about 20 psi to 50 psi. It is also understood that this process, most preferably, takes place with a single pass through, the colloid mill. However, in certain instances, it is further understood, that a second pass through a colloid mill may be advantageous. It is also understood that the second pass may be at a different gap size than the first gap size and additionally the second pass and/or second gap size can be in a second colloid mill. As a general proposition, more than two passes through a colloid mill, however, do not produce enough of an added benefit to offset the additional cost of the processing.

The amount of stabilizing agent and the type of stabilizing agent is determined by the exact constituents of liquid hydrocarbon and particulate carbonaceous material. Further, the reason for adding the stabilizing agent is to help provide a "stable dispersion" at the end of the process. Thus, the amount of stabilizing agent is generally from 0.1 to 5 weight percent, preferably from 0.2 to 1 weight percent of the final carbonaceous liquid hydrocarbon slurry. The exact amount is that amount which is needed to create this stable dispersion at the working temperatures used in transporting and burning these carbonaceous liquid hydrocarbon slurries. By "stable dispersion" is meant a dispersion which does not separate into layers of its constituent components on standing for 7 days at 60°C temperature. It will be appreciated that the least amount of stabilizing agent necessary is to be preferred. An amount of about 0.25 weight percent is adequate for many applications.

It is also understood that the carbonaceous liquid hydrocarbon slurries thus produced may become gellike in nature upon. standing. This is especially evident in slurries containing 70% or greater loadings of car- bonaceous material. It is understood, however, that all of these materials are liquid at the working temperature of approximately 60 °C.

It will be appreciated that with mixtures containing high loadings, those above 50% for example, pressure over atmospheric should be applied to advantageously allow for higher throughput rates. Generally, the pressures used are from atmospheric to 50 psi, preferably from 20 to 30 psi.

The temperature of the initial mixture generally is hot enough to process the material without further heating. However in high loadings, i.e., above 50%, it may be necessary to add auxiliary heating to the initial mixing system to prevent excessive viscosity. Generally temperatures from ambient to 135°C are more than adequate for this mixing and the temperatures created in the colloid mill by the grinding action are sufficient in all cases to process the carbonaceous liquid hydrocarbon slurries.

The gap between the rotor and the stator in colloid mills is generally adjustable within the range of 0.001" to 0.125".

An alternative method for producing the carbonaceous liquid hydrocarbon slurries incorporates starting with a mixture of liquid hydrocarbon stabilizing agent and particulate carbonaceous material wherein the amount of particulate carbonaceous material is 50 weight percent or less and then passing this mixture through the colloid mill creating a carbonaceous liquid hydrocarbon slurry. This slurry then has mixed into it either continuously or batchwise a second particulate car- bonaceous material, which may be the same or different than that initially used, having a particle distribution size of greater than 75 microns in amount from 1 to 40 weight percent, based on the total slurry weight.

Carbonaceous aqueous slurries may be produced in a manner analogous to that described above for carbonaceous liquid hydrocarbon slurries. The alternative procedures work with the aqueous slurries in the same manner as with the liquid hydrocarbon, slurries. It will be appreciated, however, that the stabilizing agent may be of a different nature because of the difference in the liquid portion of the starting mixture, i.e., water instead of a liquid hydrocarbon.

The invention is illustrated below in the examples where all percentages are by weight unless otherwise specified.

GENERAL CONDITIONS

APPARATUS

All coal was ground to a maximum 1400 micron size in a Stedman Machine Company, Inc. F44" 4 roll cage mill at a 1000/1000 r.p.m. speed having a capacity of 16 tons per hour.

The colloid mill used in all examples was a model KCD 6" of Premier Mill Corporation using a 40/60/80 fine grit carborundum stone with a gap potential between the rotor and stator of from 0.001" to .125". This mill had a flow rate capacity of up to 100 gallons per hour, and a r.p.m. of 3450.

The viscosimeters used were both Brookfield, one was a model RVT and one was a model LVT with heat sensor device, the appropriate models and appropriate spindles used are listed in the experiments.

REAGENTS

The oil used in all cases was a #6 low-sulfur fuel oil from Ashland Oil Company, Allied Oil Division, Whiskey Island having a SSF viscosity of 80 to 100 at 122 °F and a viscosity at 22 °C in a Brookfield Model RVT viscosimeter with a #2 spindle at 0.5 r.p.m. of 1920 cPs and at 5.0 r.p.m. of 1930 cPs.

The coal used in all experiments was a Falcon Coal Company bituminous coal, mined in Kentucky, U.S.A., having an analysis as follows:

Moisture 5.06% Volatile Matter 34.72% Fixed Carbon 51.48%

Ash 9.30% average of two runs

Sulfur 0.76% Carbon 70.91%

Hydrogen 4.99%

Nitrogen 1.41%

Oxygen 8.13%

BTU's per pound 12,801 True Specific Gravity 1.30

The particle distribution of the coal samples after being ground in the above-identified Stedman cage mill prior to use in the experiments were as follows :

U.S. Mesh Coal Held Coal Passed Micron Equivalent No. (Wt. %) (Wt . % ) to U.S. Mesh Size

14 1.0 99.0 1400

18 2.5 96.5 1000

25 6.5 90.0 710

50 39.2 50.8 300 100 23.0 27.8 150

200 20.5 7.3 75

325 5.1 2.2 44

STABILIZING AGENT

The stabilizing agent was used in 0.25 weight percent in every case and was a salt of a nitrogen containing base plus an alkylnaphthalenesulfonic acid.

PROCEDURE

1. A uniform coal and oil mixture was prepared by adding the coal, the oil and the stabilizing agent, in each case, in a metal 5 gallon can mixed with a Premier 2500 HV lab dispersator with a 3 1/4" high-vis lead. The particular coal to oil ratios are described in the particular examples listed in Table I.

2. The five gallon sample of each coal/oil mixture was gravity fed into the Premier KCD 6" Colloid Mill having a gap as stated for each particular experiment listed in Table I.

3. The resulting product was then collected in a second 5 gallon metal can. 4. In the cases of examples 6, 7 and 8 a cut of 70/100 U.S. mesh Falcon .Coal Company coal, as described above was added by mixing into the already prepared 50% coal/50% oil sample as described above in the 5 gallon can, using a Premier laboratory dispersator with a 1 1/2° high-vis, to bring the coal loading up to the levels indicated in these examples.

5. Each sample that was tested for its viscosity (in centipose) using the particular Brookfield viscosimeter listed in the particular parameters for each example are shown in Table I and II.

6. Examples 9 and 10 were prepared and analyzed following the particular outline set forth in each of those examples and not by the general procedure listed hereinabove. 7. The stability of each material was tested by placing a 6 oz. aliquot, in a closed top glass jar into a 60°C Blue M forced dry air type oven for seven days and tested on day 4 and day 7. Each sample was probed for sedimentation using a stainless steel spatula.

For a fuller understanding of the nature and advantages of this invention, reference may be made to the following examples. These examples are given merely to illustrate the invention and are not to be construed in any limiting sense. All quantities, proportions and percentages are by weight and all references to tempera ture are °C unless otherwise indicated.

EXAMPLES 1 - 8

Examples 1 - 8 were prepared as outlined above using the materials and apparatus outlined above. Examples 1 - 4 and 6 - 7 were run for viscosity in a Brookfield LVT viscosimeter with thermosel container at 60°C with spindle #34 at the r.p.m. indicated.

Example 5 was run on a Brookfield RVT viscosimeter at 60°C with spindle #6 at the r.p.m. indicated. The stability -of each of the samples was tested as described above.

TABLE I

Sample Coal Oil Stabilizing Agent Colloid Mill Viscosity* Stability

No. (Weight %) (Weight %) Weight % Gap Opening at 0.3 at 1.5 (4 days at (7 days at In Inches r.p.m. r.p.m. 60ºC) 60ºC)

1 50.00 49.75 0.25 0. ,005 2,000 2,200 No No Settling

Settling Pourable

2 60.00 39.75 0.25 0. .005 10,200 9.800 Pourable With Light Agitation

3 60.00 39.75 0.25 0. .006 14,40b 13,000

4 68.00 31.75 0.25 0. .-012 77,000 Pourable

5 68.00 31.75 0.25 0 .006 340,000 245,000 at 0.5 at 1.0 r.p.m. r.p.m.

6 60.00 39.75 0.25 0 .005 6,000 3,240

7 70.00 29.75 0.25 0 .005 6,000 3,360

8 80.00 19.75 0.25 0 .00 Pourable Pourable Viscosity Viscosity not run not run

* It was noted in the viscosity testing of tliese materials that there was a thiκotropic phenomenon observed.

TABLE 1 (Cont'd)

Sample No, 75 Microns or More Coarse (Weight %)

1 39 2 32

3 47 4 53 5 34 6 60 7 74 8 85

EXAMPLE 9

Example 9 is a sample of commercially available coal/oil mixture from Ashland Oil Company (Ashland COM) containing 50% by weight coal which was dry ground to meet 100% through U.S. mesh 60 and 80% through U.S. mesh 200 and 50% by weight of a #6 fuel oil which had approximately 0.25 weight percent surfactant. This sample is used to illustrate the parameters of a standard state of the art dry blend coal oil mixture. The average particle size of this material determined by wet screen analysis was found to be 95.5% through a U.S. #200 mesh. The exact parameters and analysis results will be found in Table (II) below.

EXAMPLE 10

This coal/oil mixture is prepared by taking 45 weight percent of the Falcon Coal Company coal described above in the general procedure and 54.75 weight percent of the Ashland #6 fuel oil listed above and 0.25% of the stabilizing agent listed above and then mixing them together and passing them through a Union Process Model C-3 Continuous Attritor, twice, with a total retention time of approximately 10 minutes. The average particle size range after this grinding procedure was equal to 98.9% through a U.S. #200 mesh based on wet screen analysis. The results of the testing of this material are given in Table (II) below. TAIBLE II

Sample Coal Oil Stabilizing Agent Colloid Mill Viscosity Viscosity Stability

No. (Weight %) (Weight %) Weight % Gap Opening at 0.3 at 1.5 (4 days at (7 days In Inches r.p.m. r.p.m. 60ºC) at 60ºC) 9 50.00 49.75 0.25 N.A.* 37,100 17,900 No Settling No

Pourable Settling

Pourable

With

Light

Agitation 10 50.00 49.75 0.25 N.A.* 18,000 14,700 No Settling No

Pourable Settling

Pourable

With

Light

Agitation

* N.A. •= Not Applicable - Colloid Mill not used to make these samples

While there has been shown and described what is believed at present to constitute the preferred embodiments of the present invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A carbonaceous liquid hydrocarbon slurry of low viscosity and enhanced physical stability comprising an intimate mixture of a liquid hydrocarbon, stabilizing agent and a particulate carbonaceous material, wherein said particulate carbonaceous material has at least 25%, by weight, based on the total particulate carbonaceous material weight, of particles that are more coarse than 75 microns.

2. A carbonaceous liquid hydrocarbon slurry as claimed in claim 1; wherein said liquid hydrocarbon is petroleum oil and said particulate carbonaceous material is selected from the group consisting of lignite, bituminous coal, brown coal, anthracite coal, coke, charcoal, peat, petroleum coke and mixtures thereof.

3. A carbonaceous liquid hydrocarbon slurry as claimed in claims 1 or 2 ; wherein said liquid hydrocarbon is selected from the group consisting of kerosene, fuel oils, gas oils, crude oils and mixtures thereof.

4. A carbonaceous liquid hydrocarbon slurry as claimed in claim 3 wherein said fuel oil is selected from the group consisting of number 1 fuel oil, number 2 fuel oil, number 6 fuel oil and mixtures thereof.

5. A carbonaceous liquid hydrocarbon slurry as claimed in claim 1; wherein said stabilizing agent is selected from the group consisting of surfactants, thickeners and mixtures thereof.

6. A carbonaceous liquid hydrocarbon slurry as claimed in claim 5 wherein said surfactants are selected from the group consisting of emulsifiers, dispersants, penetrants, wetting agents, spreaders and mixtures thereof.

7. A carbonaceous liquid hydrocarbon slurry as claimed in claim 1; wherein said stabilizing agent is selected from the group consisting of imidazoline quaternary salts and salts of nitrogen containing base plus an alkylnaphthalenesulfonic acid.

8. A carbonaceous liquid hydrocarbon slurry as claimed in claim 1 wherein said particulate carbonaceous material contains at least 25 weight percent of particles having size within the range from 75 microns to about 3000 microns.

9. A carbonaceous liquid hydrocarbon slurry as claimed in claim 8 wherein from 25 weight percent to about 95 weight percent of said particles have size within the range from 75 microns to about 3000 microns and greater than 50 weight percent of the balance of said particles are more finely divided than 75 microns.

10. A carbonaceous liquid hydrocarbon slurry as claimed in claim 1 wherein said particulate carbonaceous material contains at least 25 weight percent of particles having size within the range of from 75 microns to about 1400 microns.

11. A carbonaceous liquid hydrocarbon slurry as claimed in claim 10 wherein 25 weight percent to about 95 weight percent of said particles have size within the range'from 75 microns to about 1400 microns and greater than 50 weight percent of the balance of said particles are more finely divided than 75 microns.

12. A carbonaceous liquid hydrocarbon slurry as claimed in claim 11 wherein 30 weight percent to about

75 weight percent of said particles have a size within the range from 75 microns to about 1400 microns and greater than 50 weight percent of the balance of said particles are more finely divided than 75 microns.

13. A carbonaceous liquid hydrocarbon slurry of enhanced physical stability comprising an intimate mixture of a liquid hydrocarbon, stabilizing agent and greater than about 50 weight percent, basis weight of said slurry, of particulate carbonaceous bituminous coal material, with said slurry having a Brookfield viscosity at 0.3 r.p.m. of less than about 5000 cPs at 122°F.

14. A carbonaceous liquid hydrocarbon slurry of enhanced physical stability comprising an intimate mixture of a liquid hydrocarbon, stabilizing agent and greater than about 60 weight percent, basis weight, of particulate carbonaceous material, with said slurry having a Brookfield viscosity at 0.3 r.p.m. of less than about 10,000 cPs at I22°F.

15. A carbonaceous liquid hydrocarbon slurry comprising: 9.9-89%, by weight, based on the total slurry weight, of a liquid hydrocarbon; 0.1-5%, by weight, basedon the total slurry weight, of a stabilizing agent; and 10-90%, by weight, based on the total slurry weight, of a particulate carbonaceous material; wherein said particulate carbonaceous, material contains at least 25%, by weight, based on the total particulate carbonaceous material weight, of particles that are more coarse than 75 microns.

16. A carbonaceous liquid hydrocarbon slurry as claimed in claim 15; wherein said liquid hydrocarbon is petroleum oil and said particulate carbonaceous material is selected from the group consisting of lignite, bituminous coal, brown coal, anthracite coal, coke and petroleum coke and mixtures thereof.

17. A carbonaceous liquid hydrocarbon slurry as claimed in claims 15 or 16; wherein said liquid hydrocarbon is selected from the group consisting of kerosene, fuel oils, gas oils, crude oils, and mixtures thereof.

18. A carbonaceous liquid hydrocarbon slurry as claimed in claim 15; wherein said stabilizing agent is selected from the group consisting of surfactants, thickeners and mixtures thereof.

19. A carbonaceous liquid hydrocarbon slurry as claimed in claim 15; wherein said stabilizing agent is selected from the group consisting of an imidazoline quaternary salt and a salt of a nitrogen containing base plus an alkylnaphthalenesulfonic acid.

20. A carbonaceous aqueous slurry of low viscosity and enhanced physical stability comprising an intimate mixture of water, a stabilizing agent; and, a particulate carbonaceous material; wherein said particulate carbonaceous material has at least 25%, by weight, based on the total particulate carbonaceous material weight, of particles that are more coarse than 75 microns.

21. A carbonaceous aqueous slurry as claimed in claim 20; wherein said particulate carbonaceous material is selected from the group consisting of lignite, brown coal, bituminous coal, anthracite coal, coke and petroleum coke and mixtures thereof.

22. A carbonaceous aqueous slurry as claimed in claim 20; wherein said stabilizing agent is selected from the group consisting of surfactants, thickeners and mixtures thereof.

23. A carbonaceous aqueous slurry as claimed in claim 20; wherein said stabilizing agent is selected from the group consisting of an imidazoline quaternary salt and a salt of a nitrogen containing base plus an alkylnephthalenesulfoniσ acid.

24. A carbonaceous aqueous slurry of low viscosity and enhanced physical stability comprising an intimate mixture of 9.9-89%, by weight, based on the total slurry weight, water; 0.1-1%, by weight, based on the total slurry weight, of a stabilizing agent; and, 10-90%, by weight, based on the total slurry weight, of a particulate carbonaceous material; wherein said particulate carbonaceous material contains at least 25%, by weight, based on the total particulate carbonaceous material weight, of particles that are more coarse than 75 microns.

25. A carbonaceous aqueous slurry as claimed in claim 24; wherein said particulate carbonaceous material is selected from the group consisting of lignite, bituminous coal, brown coal, anthracite coal, coke and petroleum coke and mixtures thereof.

26. A carbonaceous aqueous slurry as claimed in claim 24; wherein said stabilizing agent is selected from the group consisting of surfactants, thickeners and mixtures thereof.

27. A carbonaceous aqueous slurry as claimed in claim 24; wherein said stabilizing agent is selected from the group consisting of an imidazoline quaternary salt and a salt of a nitrogen containing base plus an alkylnaphthalenesulfonic acid..

28. A process for producing a carbonaceous liquid hydrocarbon slurry of low viscosity and enhanced physical stability comprising; a) establishing a fluid intimate mixture comprising; a liquid hydrocarbon, a stabilizing agent, and a particulate carbonaceous material having at least 25%, by weight, based on the total carbonaceous material weight, having particles that are more coarse than 75 microns; b) introducing at elevated pressure said mixture of (a) into a colloid mill; c) grinding said mixture of (a) in said colloid mill under elevated pressure; and d) withdrawing the resultant ground carbonaceous liquid hydrocarbon slurry from said mill.

29. A process for producing a carbonaceous liquid hydrocarbon slurry of low viscosity and enhanced physical stability comprising; a) introducing a liquid hydrocarbon, a stabilizing agent and a particulate carbonaceous material having at least 25%, by weight, based on the total particulate carbonaceous material weight, having particles that are more coarse than 75 microns by separate feed lines under elevated pressure on each feed line thereby establishing an intimate mixture in a colloid mill; b) grinding said mixture of (a) at elevated pressure in said mill; and c) withdrawing the resultant ground carbonaceous liquid hydrocarbon slurry.

30. A process for producing a carbonaceous aqueous slurry of low viscosity and enhanced physical stability comprising; a) establishing an intimate fluid mixture comprising; water, a stabilizing agent, and a particulate carbonaceous material having at least 25%, by weight, based on the total particulate carbonaceous material weight, having particles that are more coarse than 75 microns; b) introducing at elevated pressures said intimate mixture of (a) into a colloid mill; c) grinding said intimate mixture of (a) in said colloid mill; d) withdrawing the resultant ground carbonaceous aqueous hydrocarbon slurry from said mill.

31. A process for producing a carbonaceous aqueous slurry of low viscosity and enhanced physical stability comprising; a) introducing water, a stabilizing agent, and at least 25%, by weight, based on the total particulate carbonaceous material weight, of a particulates carbonaceous material having particles that are more coarse than 75 microns by separate feed, lines under elevated pressure on each feed line thereby establishing an intimate mixture in a colloid mill; b) grinding said intimate mixture of (a) at elevated pressure in said mill; and, c) withdrawing the resultant ground carbonaceous aqueous slurry.

32. A process for producing a carbonaceous liquid hydrocarbon slurry of low viscosity and enhanced physical stability comprising; a) establishing an intimate fluid mixture comprising; a liquid hydrocarbon a stabilizing agent and at least 25%, by weight, based on the total particulate carbonaceous material weight of a particulate carbonaceous material having particles that are more coarse than 75 microns; b) introducing at elevated pressure said intimate mixture of (a) into a colloid mill; c) grinding said intimate mixture of (a) in said colloid mill under elevated pressure; d) withdrawing the resultant ground carbonaceous liquid hydrocarbon slurry adding to said ground; e) slurry of (d), from an outside source, from one to forty percent, by weight, base on the total slurry weight, of a particulate carbonaceous material having particles that are more coarse than 75 microns.

33. A process for producing a carbonaceous liquid hydrocarbon slurry of low viscosity and enhanced physical stability comprising; a) introducing a liquid hydrocarbon, a stabilizing agent, and a particulate carbonaceous material having at least 25%, by weight, based on the total particulate carbonaceous material weight, having particles that are more coarse than 75 microns by separate feed lines, under elevated pressure on each feed line, thereby establishing an intimate mixture in a colloid mill; b) grinding said intimate mixture of (a) at elevated pressure in said colloid mill; c) withdrawing the resultant ground carbonaceous liquid hydrocarbon slurry; d) adding to said ground slurry of (b), from an outside source, from 1-40%, by weight, based on the total slurry weight, of a particulate carbonaceous material having particles that are more coarse than 75 microns.

34. A process for producing a carbonaceous aqueous slurry of low viscosity and enhanced physical stability comprising; a) establishing an intimate fluid mixture comprising; water, a stabilizing agent, and a particulate carbonaceous material having at least 25%, by weight, based on the total particulate carbonaceous material weight, having particles that are more coarse than 75 microns; b) introducing at elevated pressure said intimate mixture of (a) into a colloid mill; c) grinding said intimate mixture of (a) in said colloid mill under elevated pressure; d) withdrawing the resultant ground carbonaceous aqueous slurry; 3) adding to said ground slurry of (d) from an outside source, from 1-40% be weight, based on the weight of the total slurry, a particulate carbonaceous material having particles that are more coarse than 75 microns.

35. A process for producing a carbonaceous aqueous slurry of low viscosity and enhanced physical stability comprising; a) introducing water, a stabilizing agent, and a particulate carbonaceous material having at least 25%, by weight, based on the total particulate carbonaceous material weight, having particles that are more coarse than 75 microns, by separate feed lines, under elevated pressure on each feed line, thereby establishing an intimate mixture in a colloid mill; b) grinding said intimate mixture of (a) at elevated pressure in said colloid mill; c) withdrawing the resultant ground carbonaceous aqueous slurry; d) adding to said ground slurry from an outside source from 1-40%, by weight, based on the total slurry weight, of a particulate carbonaceous material having particles that are more coarse than 75 microns.

36. A process as claimed in claims 28 or 30 or 32; wherein steps (c) and (d) are carried out two times.

37. A process as claimed in claims 29 or 31 or 33 or 35; wherein steps (b) and (c) are carried out two times.

38. A process as claimed in claims 29 or 33; wherein said liquid hydrocarbon and said stabilizing agent are introduced into said colloid mill by a sinlle feed line.

39. A process as claimed in claims 31 or 35; wherein said water and said stabilizing agent are introduced into said colloid mill by a single feed line.

40. A process as claimed in claims 28 or 29 or 30 or 31 or 32 or 33 or 34 or 35; wherein the gap size in said colloid mill is from 0.001" to 0.125"; the elevated pressure of said process is from atmospheric to 50 psi; and the temperature of said process is from ambient to 135°C.

41. A process as claimed in claims 28 or 29 or 30 or 31 or 32 or 33 or..34 or 35; wherein said gap size of said colloid mill is from 0.001" to 0.125" and the pressure on the system is from 20 to 30 psi.