Oily Contaminants Research Articles

The effect of metal type and multi-layering on friction surfacing

Friction surfacing was attempted with a stainless steel, aluminium and brass consumables on a mild-steel substrate in the open air and in flowing nitrogen. Stainless steel formed a strongly-bonded thick layer but friction surfacing with both aluminium and brass was not possible. Both brass and aluminium consumables failed to form a heated layer in contact with the mild steel, high thermal conductivity of either metal being the probable cause of failure to perform friction surfacing. Nitrogen ventilation caused cooling of the heated layer between the stainless steel and the mild-steel substrate and lowered the quality of the coating. Multi-layer surfacing by stainless steel consumables was successful, with at least three strongly-bonded layers possible, provided that the surfaces are free of oily contaminants.

Characterisation of refractory wastes at hydrocarbon-contaminated sites—II. Screening of reference oils by stable carbon isotope fingerprinting

The preliminary evaluation of stable carbon-isotope ratio mass spectrometry (IRMS) as a novel, alternative method for screening residual heavy or weathered petroleum wastes is presented. Seven well-characterised middle-to high-boiling range oils (predominant boiling range: 150–600°C) and their isolated class fractions were analysed by IRMS. Whole oil δ 13 C values (which express the ratio of 13C to 12C within each sample) showed a small but significant decrease with decreasing oil asphaltene content, from −26.8% for heavier oils to −28.8% for lighter, predominantly paraffinic oils. In agreement with the conventionally observed trend, δ 13 C values of isolated class fractions were found to increase in the following order: δ 13 C sat (≈ δ 13 C oil ) < δ 13 C aro < δ 13 C pol < δ 13 C asp , with δ 13 C sat up to 2.5% more negative than δ 13 C pol and δ 13 C asp . However, this variation was much less pronounced for the heavier oil samples. As a result, isotope type curves exhibited a clear distinction between heavier oils, which produced much flatter type curves, and lighter oils, for which type curves were characteristically sloping. From these preliminary results, IRMS would appear to have application as a potential method for identifying a predominance of asphaltene class fractions in residual hydrocarbon wastes and for distinguishing between heavy and light oily contaminants.

Establishment of Residue Analysis of Propanil (Dichloropropionanilide), Linuron and Diphenamide in Agricultural Commodities

A method for simultaneous determination of residues of three herbicides containing nitrogen, propanil (3′,4′-dichloropropionanilide), linuron and diphenamide, in agricultural commodites was established. The herbicides were extracted by acetone from samples, transferred into dichloromethane, then the dichloromethane extract was dried. The residue was dissolved in n-hexane, and purified from oily contaminants by partition with acetonitrile. The acetonitrile extract was further purified by Florisil column chromatography with dichloromethane. Diphenamide was determined directly by use of gas chromatograph equipped with a flame-thermoionic detection system (FTDGC). DCPA and linuron were derivatized into their N-monomethyl derivatives by a strong methylation method by use of sodium hydride and methyl iodide in a mixture of dimethyl sulfoxide and benzene, and then subjected to determination by FTD-GC. Recoveries of the three herbicides from brown rice, barley, corn, potato, carrot and onion were not less than 80% at the additional level of 1.0 ppm, while not less than 70% at 0.1 ppm level, respectively.

Disposal of sour caustic wastes with utilization of carbonated products

This article presents data obtained in the carbonation of sour caustic waste (SCW) from the Ufa refinery in a pilot unit. It is determined that when the ratio between the SCW and carbon dioxide is increased from 1:43 to 1:83, the residual content of hydrogen sulfide in the soda solution is lower, and the degree of removal of hydrogen sulfide from the SCW is greater. When the carbon dioxide input is further increased, the degree of removal of hydrogen sulfide drops off due to the increase in the relative amount of gas bypassing, the lower degree of purification, and poorer utilization of the carbon dioxide. A simplified flow plan of a proposed unit for SCW carbonation is presented. In the recommended scheme, the SCW from the process units is fed under pressure to a tank, where it is separated from the purge gas, and oily materials and solid contaminants are removed. The oily materials are returned as feed from the atmospheric-vacuum pipestill unit. The gas evolved from the SCW, consisting of hydrogen sulfide and light mercaptans along with carbon dioxide, passes through the carbonator and is discharged, along with the hydrogen sulfide, to the unit for sulfur utilization. The proposedmore » scheme makes it possible not only to dispose of the SCW, but also to utilize the carbonated products directly in the refinery.« less

油水分離について

An aquatic environment in Japan is claimed to have been progressively improved on the whole, but as to the water pollution caused by oily wastes there remain severe problems yet.Oily waste water is roughly distinguished into two types. The one is a waste water containing free oil droplets, which can be recovered with a relatively simple treatment and effected with the use of physical procedures. Another is a waste water containing emulsified oil, which is so minutely dispersed as to need chemical or physico-chemical treatments.So far, many apparatuses have been developed to treat such oily waste waters, but few compact machines are found that can remove oily contaminants effectively.So, we studied such machines in detail, and the experience in mineral processing has enables us to develop a flotative oil separator which has a aeration mechanism like a flotation machine. Afterwards, we have developed a variant fitted with a static mixer instead of an aeration impeller. By applying these machines to the treatment of an effluent from the gas station's waste water ponds, many favorable performance data have been obtained.

Wheel/rail adhesion — the overriding influence of water

Water from the atmosphere affects all rails, depositing in quantities far greater than the minute amounts of oily contamination normally present. Laboratory experiments are described which show how water reduces friction between rail and tyre steel surfaces. Depending on the amount of oily contamination the friction coefficient is reduced to a value between 0.3 (no oil present) and the friction which is characteristic of an excess of the oil. Lower friction on oil-free surfaces is observed using laboratory machines which involve continuous rolling; water mixes with wear debris or surface rust to form a lubricating paste and friction coefficients as low as 0.05 result. The lowest friction occurs when the ratio of water to debris is small and a viscous (non-Newtonian) paste is formed which is observed on the laboratory rigs for a few seconds whenever wetted surfaces are on the point of drying completely. Trains similarly encounter low adhesion in slightly wet conditions, most noticeably on little used lines where a substantial coverage of debris particles is present on the wear band.

Removal of mineral oil from engineers' overalls.

During the past year a great deal of attention has been given to the question of contamination of working clothes by mineral oils, and some firms have introduced schemes aimed at reducing the skin hazard from this cause. The basis of all the arrangements known to us is to ensure that all engineering overalls are laundered weekly. Some firms supply each of the workers with two pairs of overalls and have arrangements with laundry companies whereby soiled overalls are collected for laundering once weekly and freshly laundered overalls are delivered. Other firms do not supply the overalls but make them available to the workers at low cost. Some firms bear the cost of the launder ing, in others this cost is borne by the worker, but no doubt where arrangements have been made for regular laundering of bulk quantities the cost of this service to the individual is less than it other wise would be. In yet other firms a small sum of money is included in the weekly pay packet to defray the cost of laundering overalls, the worker making his own arrangements for this. Observation of the state of many of the overalls in one factory where the last mentioned arrangements operate led to doubts about the application of the money supplied to the workers for laundering over alls. A suit of overalls was obtained from one worker on a Wednesday. We accepted his statement that his overalls are laundered weekly and that the suit in question had been brought into use 'clean' on the Monday. The 16 sq ft (1-48 m2) of material which comprised the legs and waist pieces were submitted to solvent extraction and yielded over 3 oz (0-09 kg) of a viscous dark brown mineral oil which contained fine silica particles and minute metal turnings from which it was freed by filtration. This oil was saturated aliphatic in nature and had a strong ultraviolet fluorescence; there can be no doubt that it originated from lubricants and cooling oils used in the metal working process. This finding posed several questions : 1. Where laundering of overalls is left to the worker is it likely that this will be done regularly and efficiently ? 2. Is once weekly laundering sufficient or should the interval be shorter ? 3. How efficient is wet laundering of overalls in removing mineral oil contamination ? To resolve these questions 12 pieces of a cotton fabric known as blue drill, each 1 ft square (009 m2), were obtained from a local overall manufacturer and washed in anionic detergent three times and well rinsed in order to free the material from both synthetic and farinaceous sizes and dressings. They were then air dried down to an approximate normal moisture regain of 7% and thereafter six were inoculated with a light grade of engineering lubricant, corresponding approximately to S.A.E. 10 and six were inoculated with a heavy grade corre sponding to S.A.E. 30. Application took the form of total immersion in a 1 to 6 vol/vol solution of the lubricant in petroleum ether. Air drying was allowed to proceed together with drip drying and on an average it was found that 6-4 g (range 6-19 to 6-72) of the S.A.E. 10 oil and 6-7 g (range 6-2 to 71) of the S.A.E. 30 oil were absorbed by the 1-sq ft samples of the blue drill material. After approximately 24 hours air drying, when the test pieces no longer smelled of petroleum ether, they were wet laundered in hot soft water using a well-known brand of anionic detergent which contained soda-ash, metasilicate and carboxymethyl cellulose as manufacturer's additives. This detergent formula is similar to those recommended by the British Launderers' Research Association. After rinsing and normal drying the test pieces were exhaustively extracted and it was found that the S.A.E. 10 test pieces still contained 3-3 g (range 2-9 to 3-59) of oily contaminant and the S.A.E. 30 pieces 3-9 g (range 3-49 to 4-31)

CLEANING BY SURFACE DISPLACEMENT OF WATER AND OILS

An effective and economical surface-chemical displacement of water and (or) oily contamination on solid surfaces can be accomplished with certain classes of organic compounds and emulsions made from them. The essential displacement mechanism is the creation of maintenance of a surface tension gradient in the free surface of any liquid coating the solid. Such a gradient can be maintained with a drop of a spreading agent which escapes from the liquid surface by solution or evaporation after a few cm. Of travel away from the point of application. The resulting movement of the surface monolayer of agent carries along the liquid coating by a viscous-drag process. Permanent (irreversible) displacement of the liquid coating takes places only when the displacing agent (or a specific surfaceactive component in it) is able to adsorb strongly on the solid surface to form an insoluble, low-energy, surface film. Water displacers include aliphatic alcohols from propyl to hexyl, methyl amyl ketone, acetylacteone, amyl acetate, Cellosolve acetate, ethyl acetoacetate, butyl or propyl lactate, ethyl or methyl carbonate, and the Cellosolves. Effective and economical oil-displacing agents for removing many common types of oily films are readily prepared from emulsions in water of an organic liquid which has (1) a significantly high solubility in that oil. A variety of successful applications to salvaging valuable and complex military equipment, including motors, generators, switch gear, radio receivers and transmitters, radars, and various mechanical devices are described, and suitable techniques and procedures for such operations are summarized. Numerous applications are indicated for routine maintenance cleaning or salvaging and re storing to useful service for a wide variety of types of mechanical, electrical, and electronic equipment after flooding. Work is summarized in developing: (a) cleaning emulsions for rapidly and economically removing oily coatings from mechanical, electric, or electronic equipment, (b) water-displacing compounds that rapidly displace water from surfaces of equipment, parts, and crevices accessible to a liquid spray and thus accelerate greatly the drying process, (c) aggressive chemical cleaners to remove corrosion products not otherwise removed, and (d) special techniques for facilitating the chemi cal salvaging process.

Pilgrim Trust Lecture, Molecular layers

If fragments of camphor are placed upon a clean water surface they move about vigorously and may even be made to propel toy boats. The late Lord Rayleigh (1890 a, 1890 c) found that these movements stopped rather abruptly if the surface tension of the water was lowered by 21 dynes/cm. by oily contamination of the surface. The amount of olive oil needed for this purpose was surprisingly small, corresponding to a thickness of only 16 A (16 x 10 -8 cm.). Miss Pockels (1891) proved that any amount of olive oil less than enough to give a critical thickness of about 10 A had no effect whatever on the surface tension of water, but above this limit the surface tension decreased rapidly as the amount of oil was increased. Only 5 g. of olive oil would be needed to cover an acre of water surface with a film of this critical thickness. Miss Pockels also showed that accidental contamination of the surface, which had previously complicated nearly all observations of surface-tension phenomena, could be eliminated by using a trough filled to the brim with water, and sweeping impurities off the surface by the motion of barriers which rested on the edges of the trough. This use of movable barriers to confine films, to compress them or to remove them from the surface, laid the foundation for nearly all the modern work with films on water. The early theories of surface tension had been developed by physicists (Thomas Young 1805; Laplace, Gauss, etc.) who either treated liquids as continuous fluids between whose elements of volume forces acted, or considered only spherical molecules which exerted upon one another forces that varied as a function of the distance between molecular centres. Such theories naturally could not take into account the wealth of knowledge that had been accumulated by organic chemists regarding the structures of organic molecules.

A rapid method for determining the lowering of tension of exposed water surfaces, with some observations on the surface tension of the sea and of Inland waters

Ordinary methods of determining surface tension require a certain amount of apparatus and time, and often disturb the surface, thereby altering the tension of a water surface covered by a film of oil. As it was desired to make a number of observations on the amount of invisible contamination on the sea, a method depending on the spreading power of drops of mixtures of different fatty substances has been worked out. An oil will just spread against an amount of contamination which lowers the tension by an amount equal to the spreading force, or “spreading coefficient”, of the oil. Pure long chain hydrocarbon oils do not spread on clean water; if small amounts of substances containing water-attracting groups in the molecule are dissolved in the hydrocarbon, spreading occurs, the spreading force depending on the amount of the second substance with the water-attracting group, in the solution. The theory has been treated particularly thoroughly by Langmuir (1933); this paper is, however, concerned only with the application of solutions of different concentrations of a substance such as dodecyl alcohol, in a pure, rather heavy, hydrocarbon oil, to the determination of the surface tension of either fresh or salt water. It is found that the behaviour of a single drop of each of three or four such solutions, observed for half a minute or so, indicates the value of the surface tension within an accuracy of 1 dyne/cm. Calibration against water surfaces with oily contamination depressing the tension by known amounts is of course required; this is however quickly done, once for all, and it is possible to find substances for the spreading solutions which behave similarly on waters differing widely in acidity and in salt content.