Oil Agglomeration Research Articles

Effects of oil concentration and particle size on the cleaning of Spanish high-rank coals by agglomeration with n-heptane

The response of three high-ash Spanish anthracites to agglomeration with n-heptane was evaluated by measuring the organic matter recovery, ash rejection and pyritic sulfur rejection. The influence of oil concentration and coal particle size on the agglomeration results was investigated. The combustible recoveries of these coals increased to a maximum as the n-heptane concentration is raised, and then decreased. Ash rejection fell as the coal recovery increased. The effect of oil concentration on pyritic sulfur rejection was comparable with that on ash rejection. Regarding ash, pyritic sulfur was removed from one coal with noticeable selectivity. Ash rejection and organic matter recovery were improved by grinding one coal to <45 μm. Coal particle size had a more pronounced effect than n-heptane concentration on selectivity of oil agglomeration for cleaning this coal.

95/05928 Charcoal deashing by an oil agglomeration process: Effect of various operating parameters

95/05928 Charcoal deashing by an oil agglomeration process: Effect of various operating parameters

95/04463 Information about coal preparation at Rudzka Coal Company S.A.

Oil agglomeration is an effective technique for recovering and deashing coal fines. Conditioning is the most important unit operation prior to agglomeration or size enlargement. In this study, the effects of the design and process parameters in the conditioning step, which markedly influences the effectiveness of selective oil agglomeration, on the recovery of agglomerate and the ash and pyritic sulfur content of the agglomerates were investigated. It was found that the success of the process in terms of both recovery and selectivity for a brown coal was highly dependent on the conditioning parameters. In addition, an empirical equation which relates the recovery with all the conditioning parameters was developed. The values calculated by this equation closely matched the experimental values.

Investigations of Coal Purification by Selective Oil Agglomeration

Selective oil agglomeration is used as a physical method to reduce impurities in coal fines. The efficiency of the process depends on many factors. The effects of many operating variables have been examined for different coals and tailings, and the efficiency of the process in coal cleaning has been demonstrated. This study summarizes the work carried out in order to develop coal oil agglomeration as a technique for a cleaner coal-water-fuel slurry production.

Recovery of Carbon Values from Horizontal Zinc Retort Residues

Abstract Old horizontal and vertical retort Zn smelter sites are being examined by Federal and State environmental agencies because the residues and other wastes contain Pb and Cd. Residues at some of the sites have been declared hazardous wastes. Conservative estimates place the amount of these wastes at 36 Mmt. There are a number of sites with up to 0.4 Mmt of wastes in Kansas, Illinois, and West Virginia and one in Pennsylvania with 27 Mmt of wastes. In addition to their C content (20–30%), the residues represent a possible resource for Ge, Ga, In, Ag, Mn, Pb, and Zn. Samples obtained from several sites near Gas, Kansas are being used in research attempting to recover the unburned C and the metal values as separate products, leaving a nonhazardous residue that could be disposed of safely and economically. The residue was ground to liberate the C. Initial efforts to recover the C used oil agglomeration. This method recovered 67–781% of the C at grades of 66–79% but required large quantities of oil; the absence of agglomeration made separation difficult. Froth flotation has recovered 64–85% of the C in concentrates grading 54–84%.

Recovery of waste fine coal by oil agglomeration

Demineralization of Blue Creek coal by selective agglomeration using diesel oil involves high-shear mixing to disperse the diesel in a slurry of fine coal and separation of the resulting agglomerates from the tailings. A total of 54 agglomeration trials were made with thickener underflow from the Jim Walters Resources Inc. No. 4 mine preparation plant. Two additional particle size distributions of the thickener underflow were obtained by wet grinding and all three coals were stored under water. All experiments were performed at room temperature. The feed which has less than 1 wt% of total sulfur is suitable for recovery by oil agglomeration. Ash rejection and recovery of combustibles is approximately 80%. The effects of blending the agglomerates with a coal-water fuel are reported.

Charcoal deashing by an oil agglomeration process: effect of various operating parameters

This paper describes our attempt to transfer current knowledge on mineral coal deashing by selective oil agglomeration to charcoal. The effects of various operating variables, e.g. particle size, conditioning, oil dose, oil type, amount of volatile matter and time of agglomeration were studied. It was found that a ratio of 0.2% hydrochloric acid (32% concentrated) to charcoal and a 5 min conditioning time are ideal for deashing. Domestic fuel oil and crude palm oil were used as bridging liquids. The results show that by reducing the particle size (8 μm mean diameter), charcoal can be deashed to as low as 0.8% in weight, whilst recovery stay virtually at 100%. The use of charcoal with a high volatile matter content (more than 20%) allows easy deashing even with larger particle sizes (15 μm diameter).

Recovery of waste fine coal by oil agglomeration

Recovery of waste fine coal by oil agglomeration

95/00073 Deep cleaning of a hvA bituminous coal using a polyethylene oxide/polypropylene oxide block co-polymer

Deep cleaning of a hvA bituminous coal using flotation process was investigated in this study. A -1/4 inch raw coal containing about 35% ash was subjected to initial flotation tests at nominal feed sizes of -600 {mu}m and -212 {mu}m. In both cases a clean coal product of 13% ash with a combustible matter recovery of about 80% was obtained. Since the ash content was much too high for deep cleaning, a second sample which was the product of a conventional coal preparation plant was used in subsequent studies. It contained about 7% ash. The material was wet ground to nominal feed sizes of -600 {mu}m, -212 {mu}m and -65 {mu}m, respectively, and floated using n-dodecane as collector. The reduction in ash was marginal for the -600 {mu}m and -212 {mu}m coals. However, a clean coal product of 3.9% ash could be obtained with a high yield using -65 {mu}m feed. The product quality was further improved by introducing a mild oil agglomeration stage prior to flotation and by using an ethylene oxide/propylene oxide block copolymer as an additive. The ash content of the clean coal so obtained was 2.5% with a combustible matter recovery of about 76%.

Hydrophilic colloids and the elimination of inorganic sulfur from coal: a study employing contact angle measurements

Selective oil agglomeration, which is an effective method of eliminating inorganic sulfur from coal, can be further improved in its efficiency by means of the addition of boiled starch. (Starch that was not boiled had a barely detectable effect.) We have measured the oil—water—solid contact angle θ s12 on coal and on iron pyrite (FeS 2) and have discovered that starch makes iron pyrite more hydrophilic without appreciable loss of hydrophobic character of the coal. Measurements of the effect of n-octanol on θ s12, and on the n-decane—water interfacial tension, were also made. The Young equation can be combined with the Gibbs equation, with a result in the form ▪ which we may call the Gibbs—Young equation. We have used this expression to show that n-octanol is more strongly adsorbed at the solid—water interface than at the solid—oil interface. We have carried out laboratory runs of the modified oil agglomeration process, and found that as much as a 55% reduction in pyritic sulfur, below the level obtained without starch, can be achieved, as well as a reduction in ash by as much as 38%.

The role of air in oil agglomeration of coal at a moderate shear rate

The agglomeration of an aqueous suspension of highly hydrophobic coal particles with heptane or hexadecane was investigated with a laboratory mixing unit equipped with a flat-blade, turbine agitator which produced a moderate shear rate. The ground sample of coal from the No. 2 gas seam in West Virginia was subjected to agglomeration conditions both with and without air present in the closed mixing unit. Although compact, nearly spherical agglomerates were produced both in the presence and absence of air, the rate of agglomeration was much greater, and larger agglomerates were produced with a given amount of oil when air was present. Having air present also improved product quality and recovery. The effect of air was greater with smaller amounts of oil than with larger amounts.

Modified oil agglomeration process for coal beneficiation. III. Grinding and agglomeration using different szego mill designs

The simultaneous grinding/agglormeration process has been used to beneficiate Minto coal. Experiments with the Szego Mill, a planetary ring-roller mill with grooved rollers, have given good results. Different roller ridge/groove sizes have been tested and favourable oil-coal-water ratios established. Ash removal is closely related to grinding performance. Very short mill residence times, of the order of 10 seconds, are sufficient for microagglomerate formation. Considerable equipment and operating cost savings are possible with the modified process. On a utilise le procede de pulverisation et d'agglomeration simultanees en vue de valoriser le charbon Minto. Les experiences menees avec le broyeur Szego, un laminoir planetaire a cylindres annulaires et canneles, ont donne de bons resultats. Differentes tailles de cannelure et d'arěte ont ete testees et des rapports huile-charbon-eau favorables ont ete etablis. La recuperation des cendres est etroitement liee a la performance de la pulverisation. Des temps de sejour dans le broyeur tres courts, de l'ordre de 10 secondes, sont suffisants pour la formation de microagglomerats. Ce procede modifie permet des economies d'equipement et de temps de fonctionnement considerables.

Modified oil agglomeration process for coal beneficiation. iv. pilot‐plant demonstration of the simultaneous grinding‐agglomeration process

AbstractSimultaneous grinding and agglomeration (SGA) in the novel Szego Mill allows significant simplifications and energy savings. The excess grinding energy is used for mixing and agglomerate formation. Results are reported over a range of operating conditions. The SGA process has been demonstrated in the laboratory and in a 12 tonnes/day pilot plant with satisfactory results. The economics of coal beneficiation for slurry fuel preparation is considered.

物理的選別法による石炭の脱灰性に関する研究 （第３報） 微粉炭の脱灰試験法と脱灰性評価

Release analysis (RA) and oil agglomeration (OA) procedures were investigated to determine a standard testing method for de-ashing of fine (>10μm) and ultra-fine (<10μm) coal. The results indicated that OA was suitable for both fine and ultra-fine coal, but RA only for fine coal. Oil agglomeration tests were carried out for Datong, Wandoan and Illinois coals of different sizes. Based on the liberation model previously proposed by the authors and the removal characteristics of mineral matter by the oil agglomeration, a new simulation method was developed to predict the amount of minerals and ash content of clean coal. There was good agreement between experimental and calculated results for the clean coal of agglomerates.

A Modified Suction Potential Method for Measuring the Three-Phase Contact Angle

Abstract The suction potential method for measuring the three-phase contact angle was modified and used to determine the oil-water-solid contact angle for various samples of coal. The method involves measuring the pressure changes required to draw an oil/water interface and then an oil/air interface into a packed bed of solid particles. Before the latest modification, the method was very time consuming and difficult to control. These problems were overcome by modifying the apparatus and measuring technique. Values of the contact angle determined with the new technique were very similar and as reproducible as those determined with the older method. Also, measurements of the contact angle for a series of oxidized coal samples were consistent with other surface property measurements. In addition, for this series of samples, the recovery of coal from an aqueous suspension by oil agglomeration was found to correlate very well with the contact angle.

微粉炭燃焼フライアッシュ中の炭素分の性状

Fly ashes E and G those discharged from a same pulverized coal combustion boiler were classified into two components, such as smaller fly ash particle under 38, a m and larger fly ash particle above 125 μm. The carbon cotained in both components were separated from fly ash by using the Ultrasonic Oil Agglomeration method. Properties of separated carbons were investigated by applying the X-ray diffraction, SEM (Scanning Electron Microscope), EDX (Energy Dispersive X-Ray Micro Analyzer) and TGA (Thermogravimetric Analysis). Following results are obtained.(1) The carbon remains in the larger fly ash as the unburned char, and that cotained in smaller fly ash are carbon black and rock carbon.(2) Significant differences of the carbon contents and their properties between the fly ashes E and G are found. The carbon content in smaller components of fly ash G is fairly greater than that in smaller components of fly ash E, although the coal G shows a good combustibility.These observations of the properties of carbon containing in fly ash present significant informations on the for rational operation and control in the process of pulverized coal combustion process.

資源リサイクルプロセスにおける湿式造粒技術の適用

資源リサイクルプロセスにおける湿式造粒技術の適用

Effect of Oxidation and Thioglycolic Acid on Separation of Coal and Pyrite by Selective Oil Agglomeration

The separation of coal and pyrite particles by selective agglomeration with oil can be troublesome for coals which are weakly hydrophobic or hydrophilic and, therefore, are not strongly agglomerable. The hydrophobicity of lower rank coals and other coals which have become oxidized is generally low. On the other hand, the hydrophobicity of oxidized pyrite can be appreciable. The problem of separating such coals from pyrite was studied by oxidizing a moderately hydrophobic coal with air at 150°C for either 8, 20, or 72 hr to systematically reduce its hydrophobicity. Samples of the raw and treated coal were subsequently mixed with aged mineral pyrite from Peru and agglomerated with heptane. Although a mixture of raw, unoxidized coal and pyrite was largely separated by this method, it proved increasingly difficult to separate the materials as the coal became increasingly oxidized. While raw coal was agglomerated in preference to pyrite, this preference changed as the coal was oxidized. After 20 hr. of oxi...

The spherical oil agglomeration of barite suspensions in the presence of surfactant and cosurfactant

The spherical agglomeration of barite particles using oil in the presence of both surfactant and cosurfactant was studied. It was found that the mineral suspension needed a critical surfactant concentration to initiate oil agglomeration. The addition of long-chain aliphatic alcohols to the organic phase decreased the critical surfactant concentration. This phenomenon was ascribed to a screening effect of alcohol molecules in the adsorption layer of surfactant. When sodium chloride was added to the solution the spherical agglomeration disappeared even though the surfactant adsorption at the barite/solution interface increased. It was concluded that the disappearance of oil agglomeration was caused by a bilayer of the surfactant which was formed on the barite surface. In the barite—surfactant—alcohol—oil—brine system the agglomeration process is only realized with the long-chain alcohols. This behaviour can be explained by microemulsion formation at the mineral/solution interface.

The role of air in oil agglomeration of coal at a moderate shear rate

Abstract The agglomeration of an aqueous suspension of highly hydrophobic coal particles with heptane or hexadecane was investigated with a laboratory mixing unit equipped with a flat-blade, turbine agitator which produced a moderate shear rate. The ground sample of coal from the No. 2 gas seam in West Virginia was subjected to agglomeration conditions both with and without air present in the closed mixing unit. Although compact, nearly spherical agglomerates were produced both in the presence and absence of air, the rate of agglomeration was much greater, and larger agglomerates were produced with a given amount of oil when air was present. Having air present also improved product quality and recovery. The effect of air was greater with smaller amounts of oil than with larger amounts.