Diesel emulsion

Another field where emulsions are likely to become imperative is the production of fuel [99]. Simple and multiple emulsions represent alternative fuels for diesel engines to both increase combustion efficiency and reduce particulate emission. Considering the enormous volume of diesel that is being consumed today, a replacement of just a fraction of regular diesel by diesel emulsion could be of considerable interest to the surface chemistry community. Until now, diesel emulsions were prepared by... 

A new development is the use of emulsions as fuels for vehicles. The following studies have been selected from the numerous patent sources on this topic. The possibility of making stable water-diesel emulsions containing 10% of water and 0.75% of an emulsifier whose composition is not specified is shown in [248]. When the water content increases, the emulsions break. 

Characteristics of Emulsified Acid. Al-Anazi et al. [14] measured the apparent viscosity of the acid-in-diesel emulsion as a function of shear rate at various temperatures by using a Brookfield viscometer Model DV-II. Figure 3 shows that the apparent viseosity decreased as the shear rate was increased. This result indieates that the aeid-in-diesel emulsion is a non-Newtonian fluid (shear-thinning behavior). Crowe and Miller [45] and Krawietz and Rael [53] reported a similar behavior. The apparent viscosity ( /) can be predieted over the shear rate (y) examined using the power-law model given by the following equation ... 

Stability of Acid-in-Diesel Emulsions. Al-Anazi et al. [14] showed that acid-in-diesel emulsion is stable for more than three days at room temperature. However, at high temperatures it breaks down and an aqueous (acidic) phase was noted at the bottom of the test tube. Figure 4 depicts the volume of the separated aqueous phase as a function of time at 96 °C. The aqueous phase first appears after 85 minutes. The volume of separated acid gradually increases until complete phase separation occurs after nearly 220 minutes. In the presence of reservoir rock, the aqueous phase appears after approximately 20 minutes, and complete phase separation takes place after an hour. These results indicate lower emulsion stability in the presence of calcite. The acid reaction with the carbonate rock produces water (which causes the pH to rise) and calcium chloride. It appears from these results that the surfactant moves away from the acid-diesel interface as the pH or ionic strength increases, which causes the emulsion to break. 

The droplet size of the dispersed phase plays a key role in the effectiveness of the acidizing job. Too fine or coarse droplets will adversely affect the efficiency of the stimulation job. The acid-in-diesel emulsion was examined under the microscope and the drop size distribution of the dispersed phase determined using a phase contrast technique. 

Figure 5 is a photomicrograph (250 x ) of an acid-in-diesel emulsion. The average droplet size for this acid-in-diesel emulsion is nearly 77 pm [14]. Excellent field results were claimed when this acid was used to stimulate carbonate formations with permeability less than 100 mD [14,15]. 

Figure 6 illustrates that the emulsified acid has a much lower dissolution rate compared with regular 15 wt% HCl [14]. The regular 15 wt% HCl dissolved 90 wt% of the rock after 6 minutes. However, the acid-in-diesel emulsion dissolved 2wt% of the sample after the same period of time. This result indicates that the dissolution rate of the emulsified acid is slower than that of the 15 wt% HCl by a factor of 45. 

The density of heavy fuels is greater than 0.920 kg/1 at 15°C. The marine diesel consumers focus close attention on the fuel density because of having to centrifuge water out of the fuel. Beyond 0.991 kg/1, the density difference between the two phases —aqueous and hydrocarbon— becomes too small for correct operation of conventional centrifuges technical improvements are possible but costly. In extreme cases of fuels being too heavy, it is possible to rely on water-fuel emulsions, which can have some advantages of better atomization in the injection nozzle and a reduction of pollutant emissions such as smoke and nitrogen oxides. 

A. Lawson, A. J. Last, A. S. Desphande, and E. W. Simmons, "Heavy-Duty Tmck Diesel Engine Operation on Unstabihzed Methanol/Diesel Euel Emulsion," SAE Paper 810346, (SP-480) Int. Congress and Expo (Detroit, Mich., Peb. 23—27,1981) Society of Automotive Engineers, Warrendale, Pa. 

Emulsifiers are incorporated in oil and synthetic mud formulations to maintain a stable emulsion of the internal brine phase. These materials include calcium and magnesium soaps of fatty acids and polyamines and amides and their mixtures (123,127). The specific chemistry of these additives depends on the nature of the continuous phase of the mud, ie, whether diesel oil, mineral oil, or a synthetic Hquid. Lime is added along with the fatty acid to form the... 

Oil-Base Muds. Oil-base muds contain oil as the continuous phase and water as the dispersed phase. Oil-base muds contain less than 5% (by volume) water, while oil-base emulsion muds (invert emulsions) have more than 5% water in mud. Oil-base muds are usually a mixture of diesel fuel and asphalt the filtrate is oil. 

SANDS Low pressure. Water or mud blocking. Loss of crude or diesel oil used as completion fluid. Minimum filtration rate water-base muds. Minimum filtration rate water-base emulsions. Miminum filtration rate oU-base emulsions. Oil-base muds. Inhibited muds. Minimum weight muds. Crude oil or diesel oil. Add oil-soluble lost circulation material. 

Desulfurization processes are absolutely necessary for producing clean fuels. Possible strategies to realize ultradeep suffiirization currently include adsorption, extraction, oxidation, and bioprocesses. Oxidative desulfurization (ODS) combined with extraction is considered one of the most promising of these processes [13]. Ultradeep desulfurization of diesel by selective oxidation with amphiphilic catalyst assembled in emulsion droplets has given results where the sulfur level of desulfurized diesel can be lowered from 500 ppm to about 0.1 ppm without changing the properties of the diesel [12]. 

Acetals and oleophilic alcohols or oleophilic esters are suitable for the preparation of inverted emulsion drilling muds and emulsion drilling muds. They may replace the base oils, diesel oil, purified diesel oil, white oil, olefins, and alkylbenzenes [825,826]. Examples are isobutyraldehyde di-2-ethylhexyl acetal dihexyl formal and mixtures with coconut alcohol, soya oil, and a-methyldecanol. 

Fluid loss additives are used are used to reduce the rate of fluid loss from the fracture to the formation and to naturally occurring macro- and micro-fractures within the formation. Silica flour (73,74), oil-soluble resins (75), diesel oil emulsions (5% by volume) (74) have also been used. 

Desulfurization of other diesel feedstocks from Total Raffinage was also reported by EBC. In these studies, different engineered biocatalysts were used. Two different middle distillate fractions, one containing 1850 ppm sulfur and other containing 650 ppm sulfur, were tested. R. erythropolis sp. RA-18 was used in one experiment and was reported to desulfurize the diesel from 1850 to < 1200ppm sulfur within 24 hours. On the other hand, it removed sulfur from a middle distillate with 650ppm sulfur to below 200 ppm sulfur [222], Various Pseudomonas strains were also tested in this study and reported to remove less amounts of sulfur. A favorable characteristic of the Pseudomonas strains is their inability to form stable emulsions, which can be useful trait for product recovery. 

Diesel-like products (jet fuel, diesel. No. 2 fuel oil, kerosene) are moderately volatile products that can evaporate with no residue. They have a low-to-moderate viscosity, spread rapidly into thin slicks, and form stable emulsions. They have a moderate-to-high (usually, high) toxicity to biota, and the specific toxicity is often related to type and concentration of aromatic compounds. They have the ability to penetrate substrate, but fresh (unoxidized) spills are nonadhesive. 

Dual-phase extraction cannot remediate heavy chlorinated compounds, pesticides, or heavy hydrocarbons including polychlorinated biphenyls (RGBs), dioxin, fuel oil No. 6, or metals (with the possible exception of mercury). High-velocity pump systems (such as liquid ring vacuum pumps) tend to form emulsions, especially when diesel fuel is part of the recovered fluids. The problem of emulsion can be solved with prepump separation or a de-emulsification unit. 

Other emulsion test methods are used to rate the ability of fuel to shed water. These methods include ASTM D-1401 and the Waring Blender Test. The ASTM D-1401 method is a lubricant test method, but has been adopted by the U.S. military for rating diesel fuel demulsibility.This method is summarized by ASTM as follows ... 

Diesel-water emulsions are being studied extensively worldwide because of the impact these fuels have on reducing engine exhaust emissions, especially NOx and particulates. Although formulations vary, a typical diesel-water emulsion will contain approximately 80% to 90% diesel fuel, 10% to 15% water, and 1% to 5% of an emulsification additive mixture. The resulting fuel blend is transparent in appearance and has the typical appearance of diesel fuel. 

Diesel-water emulsions are not approved for shipment by finished product pipeline companies. Consequently, the emulsion must be made on-site or near the point of sale. Other issues currently being resolved deal with improving the cold-temperature handling properties of the high-water-content fuel and improving the long-term storage stability of fuel blends... 

Oil sprays in 1943 and 1944 saved many thousands of acres of carrots that would have been lost if hand labor had been required to weed them. Meanwhile, guayule production had utilized to the maximum the tolerance of that crop for Diesel oil emulsions. Oil sprays allowed complete mechanization of this crop, which was considered critical in our war production. 

R. E. Santelli, M. A. Becerra, A. S. Freire, E. P. Oliveira and A. F. Batista-de-Carvalho, Non-volatile vanadium determination in petroleum condensate, diesel and gasoline prepared as detergent emulsions using GFAAS, Fuel, 87(8-9), 2008, 1617-1622. 

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