Levels in petroleum

The list of metals present in major or trace level in petroleum products can vary from alkali, alkaline, transition and refractory types depending on the source and refining... 

Table 3.1. Sample Preparation Techniques Suitable for Elemental Analysis at the Nanogram Level in Petroleum Products...

HPhe Environmental Protection Agency has set strict emission standards for stationary combustion sources. No more than 0.01 /xg Be/m3 may occur in the ambient atmosphere around such sources, and a maximum of 10 g may be emitted in a 24-hr period (I). The earth s crust is estimated to contain about 0.001% beryllium, mostly as inorganic minerals. Beryllium has been reported at the parts-per-million level in coal, and in survey analyses with emission spectroscopic techniques Russian authors have reported the detection of unspecified levels in petroleum (2,3,4),... 

Although innumerable papers have been published describing the determination of lead in various matrices, only a limited amount of information is available concerning the analysis for lead at part-per-billion levels in petroleum matrices. Milner (I) has reviewed those methods which were directed specifically towards lead in petroleum products at the parts-per-million and -billion levels. 

Scope. This method describes the determination of lead at the nanogram level in petroleum and petroleum products by differential pulse... 

Scope. The method is designed to determine manganese concentrations down to the 10 ng/g level in petroleum and petroleum products. 

Recently the determination of elemental sulfur and hydrogen sulfide at sub-parts per million levels in petroleum has been achieved by preliminary extraction followed by DPP. 

The detection of thiols (RSH) is important in two main fields, biology and environment. Thiols (or mercaptans) are smelly molecules present in petroleum. However, thiols have adverse effects (corrosion) on fuel distribution systems so that processes have been developed to reduce their level in petroleum, using for example thiol oxidation processes. It is thus important to be able to control via sensing devices the levels of thiols in gasoUne. 

Bios—The bias of this test method caimot be determined since an appropriate standard reference material containing trace sulto levels in petroleum products is not available. 

When fuels are combusted, vanadium present in the fuel can form corrosive compounds. The value of crude oils can be determined, in part, by the concentrations of nickel, vanadium, and iron. Nickel and vanadium, present at trace levels in petroleum fractions, can deactivate catalysts during processing. These test methods provide a means of determining the concentrations of nickel, vanadium, and iron. 

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. 

Corrosion. The primary coal properties affecting corrosion are sulfur and chlorine levels. The range of sulfur levels in Table 2 shows a low of 0.3% for SUFCo and a high of 5.2% for petroleum coke. R F coal has 4.2% sulfur. The highest chlorine level in this group of coals is 0.41% for Pyro No. 9 coal. 

Catalytic Pyrolysis. This should not be confused with fluid catalytic cracking, which is used in petroleum refining (see Catalysts, regeneration). Catalytic pyrolysis is aimed at producing primarily ethylene. There are many patents and research articles covering the last 20 years (84—89). Catalytic research until 1988 has been summarized (86). Almost all catalysts produce higher amounts of CO and CO2 than normally obtained with conventional pyrolysis. This indicates that the water gas reaction is also very active with these catalysts, and usually this leads to some deterioration of the olefin yield. Significant amounts of coke have been found in these catalysts, and thus there is a further reduction in olefin yield with on-stream time. Most of these catalysts are based on low surface area alumina catalysts (86). A notable exception is the catalyst developed in the former USSR (89). This catalyst primarily contains vanadium as the active material on pumice (89), and is claimed to produce low levels of carbon oxides. 

The fact that we have peaks within a 2D space implies that where no peak is found represents a true detector baseline or electronic noise level. In a conventional petroleum sample, a complex unresolved mixture response causes an apparent detector baseline rise and fall throughout the GC trace. It is probably a fact that in this case the true electronic baseline is never obtained. We have instead a chemical baseline comprising small response to many overlapping components. This immediately suggests that we should have more confidence in peak area measurements in the GC X GC experiment. 

Subsurface Fluid Pressure (Pore Pressure Gradient). The total overburden pressure is derived from the weight of the materials and fluids that lie above any particular depth level in the earth. Of interest to the petroleum industry are the sedimentary rocks derived from deposits in water, particularly, in seawater. Such sedimentary rocks contain rock particle grains and saline water within the pore spaces. Total theoretical maximum overburden pressure, P (Ib/ft-), is... 

Vanadium and nickel are poisons to many catalysts and should be reduced to very low levels. Most of the vanadium and nickel compounds are concentrated in the heavy residues. Solvent extraction processes are used to reduce the concentration of heavy metals in petroleum residues. 

Platinum is used as a catalyst for nitric and sulphuric acid production, in petroleum refining and in catalytic mufflers to control air pollution. Platinum salts can cause respiratory complaints, asthma, and platinosis , an allergic response. Allergic dermatitis may also result from exposure to soluble platinum salts and once subjects have been sensitized it generally precludes continued occupational exposure at any level. The 8 hr TWA OEL for platinum metal is 5 mg/m but for soluble platinum salts it is only 0.002 mg/m. Handling precautions must include containment where possible, ventilation, personal protection, and the screening out of individuals who have become sensitized. 

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