Petroleum products limitations

The choice between X-ray fluorescence and the two other methods will be guided by the concentration levels and by the duration of the analytical procedure X-ray fluorescence is usually less sensitive than atomic absorption, but, at least for petroleum products, it requires less preparation after obtaining the calibration curve. Table 2.4 shows the detectable limits and accuracies of the three methods given above for the most commonly analyzed metals in petroleum products. For atomic absorption and plasma, the figures are given for analysis in an organic medium without mineralization. 

From complex cuts characterized in an overall manner, there is a transition towards mixtures containing only a limited number of hydrocarbon families or even compounds. This development has only just begun. It affects for the moment only certain products and certain geographical zones. It is leading gradually to a different view of both refining and the characterization of petroleum products. 

The practice of smudging is still carried out in many areas to protect orchards from frost. Petroleum products are burned in pots, producing both heat and smoke. Since the heat is the desirable product, smokeless heaters with return ducts to reburn the smoke are required by most air pollution control agencies. Some control agencies have passed regulations limiting the smoke to 0.5 or 1.0 gm per minute per burner. 

Texaco Limited, Canvey Island tank farm on the west side of the methane terminal is used to import petroleum products by sea via the two jetties, store and distribute them by tanker-trucks and sea, but mostly by the U.K. oil pipeline. The storage capacity is 80,000 tonnes of petroleum products employing about 130 people. 

London and Coastal Oil Wharves Limited bulk stores, in tanks, a variety of petroleum products and other substances that are flammable or toxic. Some tankage is leased to Texaco Limited which is connected into the UK oil pipeline for transfer from the site. Products also are rcccis cd by road and sea. The storage capacity is more than 3(X),(XK) tonnes with about fifty people employed. 

Knittel, T. 1993. Battery Site Vapor Control for Sour Oil Production Sites, Paper presented to various petroleum production companies. Westech Industrial Limited, Calgary, Alberta, Canada. 

Electrodes of the first kind have only limited application to titration in non-aqueous media a well-known example is the use of a silver electrode in the determination of sulphides and/or mercaptans in petroleum products by titration in methanol-benzene (1 1) with methanolic silver nitrate as titrant. As an indicator electrode of the second kind the antimony pH electrode (or antimony/antimony trioxide electrode) may be mentioned its standard potential value depends on proton solvation in the titration medium chosen cf., the equilibrium reaction on p. 46). 

Atomic absorption spectrometry is one of the most widely used techniques for the determination of metals at trace levels in solution. Its popularity as compared with that of flame emission is due to its relative freedom from interferences by inter-element effects and its relative insensitivity to variations in flame temperature. Only for the routine determination of alkali and alkaline earth metals, is flame photometry usually preferred. Over sixty elements can be determined in almost any matrix by atomic absorption. Examples include heavy metals in body fluids, polluted waters, foodstuffs, soft drinks and beer, the analysis of metallurgical and geochemical samples and the determination of many metals in soils, crude oils, petroleum products and plastics. Detection limits generally lie in the range 100-0.1 ppb (Table 8.4) but these can be improved by chemical pre-concentration procedures involving solvent extraction or ion exchange. 

It is generally agreed that worldwide petroleum supply will eventually reach its productive limit, peak, and begin a long term decline. One of the alternatives is the Nation s untapped oil shale as a strategically located, long-term source of reliable, affordable, and secure oil. The extent of U.S. oil shale resources, which amounts to more than 2 trillion barrels, has been known for a century. In 1912, the President established the Naval Petroleum and Oil Shale Reserves. There have been several commercial attempts to produce oil from oil shale, but these have failed because of the lower cost of petroleum at the time. With future declines in petroleum production, market forces are expected to improve the economic viability of oil shale. 

A petroleum product is excluded even if it contains other listed hazardous substances provided that those substances were not added to the oil after the refining process, and are found at concentrations normally detected in crude oil or refined petroleum products. Just what is a petroleum product is important since such determination will decide if it meets the criteria for exclusion. The two issues are (1) is the material released a petroleum product, and (2) does it contain hazardous substances otherwise listed by the EPA, which limits the applicability of the exclusion to the release in question. The EPA in 1985 interpreted the petroleum exclusion to pertain to... 

Current EPA analytical methods do not allow for the complete speciation of the various hydrocarbon compounds. EPA Methods 418.1 and 8015 provide the total amount of petroleum hydrocarbons present. However, only concentrations within a limited hydrocarbon range are applicable to those particular methods. Volatile compounds are usually lost, and samples are typically quantitated against a known hydrocarbon mixture and not the specific hydrocarbon compounds of concern or the petroleum product released. By conducting EPA Method 8015 (Modified) using a gas chromatograph fitted with a capillary column instead of the standard, hand-packed column, additional separation of various fuel-ranged hydrocarbons can be achieved. 

For the measuremeut of other petroleum products, a wide variety of tests are available, lu fact, approximately 350 tests (ASTM, 2000) are used to determiue the differeut properties of petroleum products. Fach test has its owu limits of accuracy aud precisiou that must be adhered to if the data are to be accepted. 

Freon-extractable material is reported as total organic material from which polar components may be removed by treatment with silica gel, and the material remaining, as determined by infrared (IR) spectrometry, is defined as total recoverable petroleum hydrocarbons (TRPHs, or total petroleum hydrocarbons-IR). A number of modifications of these methods exist, but one particular method (EPA 418.1 see also EPA 8000 and 8100) has been one of the most widely used for the determination of total petroleum hydrocarbons in soils. Many states use or permit the use of this method (EPA 418.1) for identification of petroleum products and during remediation of sites. This method is subject to limitations, such as interlaboratory variations and inherent inaccuracies. In addition, methods that use Preon-113 as the extraction solvent are being phased out and the method is being replaced by a more recent method (EPA 1664) in which n-hexane is used as the solvent and the n-hexane extractable material (HEM) is treated with silica gel to yield the total petroleum hydrocarbons. 

For petroleum and petroleum product releases in a sensitive area, the preferred analytical method to determine concentrations of total petroleum hydrocarbons in environmental media is the standard EPA test method (EPA 418.1). To determine concentrations of benzene, toluene, ethylbenzene, and xylenes in environmental media, other methods (EPA SW-846, SW-846 8021B, SW-846 8260) are preferred, provided that the detection limits are adequate for soil and for groundwater protection. 

A feasibility study on the application of H-NMR petroleum product characterization to predict physicochemical properties of feeds and catalyst-feed interactions has been performed. The technique satisfactorily estimates many feed properties as well as catalyst-feed interactions to forecast products yield. There are, however, limitations that have to be understood when using the H-NMR method. The technique, in general, is not capable either to estimate the level of certain contaminants such as nitrogen, sulfur, nickel, and vanadium when evaluating feed properties or the effect of these contaminants on products yields while testing catalyst-feed interactions. 

Although petroleum refiners are not unfamiliar with questions of thermal stability of petroleum products, jet fuel stability requirements (stable in the range 400—500°F) presented a new set of problems. One of the first things to be done was to define limits of acceptable stability. Such limits naturally would depend upon individual engine design and the environment to which the fuel is exposed. Fuels meeting one set of conditions could conceivably fail to meet another set. The solution devise some sort of laboratory test that would correlate with actual engine performance... 

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