Petroleum and Oil Refining & Analysis

The petroleum (oil) industry is absolutely huge and vitally important to the world economy. Global consumption of oil has steadily increased over the last decades, totalling 4.66 billion metric tons in 2018, compared to 3.46 billion metric tons about twenty years ago. And yet the total volume of oil reserves has also grown over the same time period; between 1990 and the present day the volume of global oil reserves has increased from just over 1 billion barrels to nearly 1.7 billion.

The industry covers global processes including exploration, extraction, refining, transporting and marketing. The largest volume products within the industry are fuel oil and gasoline/petrol but petroleum is also the raw material for such diverse products as pharmaceuticals, solvents, fertilizers, pesticides and plastics.

The raw, unprocessed crude oil is not generally useful in industrial applications. Instead, the hundreds of different hydrocarbon molecules in crude oil are separated in a refinery into components that can be then be used as fuels, lubricants and feedstocks in the various petrochemical processes that are used to manufacture plastics, detergents, elastomers and fibres such as nylon and polyesters.

Different boiling points allow the different hydrocarbons to be separated by fractional distillation. Since the lighter liquid products are in great demand for use in internal combustion engines, a modern oil refinery will convert heavy hydrocarbons and lighter gaseous elements into these higher value products.

Text Box: This is a diagram of a typical oil refinery fractional distillation column. The various components are separated and then further refined as required.
This is a diagram of a typical oil refinery fractional distillation column. The various components are separated and then further refined as required.
This is a breakdown of the products made from a typical barrel of oil. As can be seen over 80% of the oil ends up as some kind of fuel type.

The refining for the range of intermediates and final products can involve several stages and it is of vital importance that analytical testing is done throughout to ensure both the correct materials are being produced and that the level of impurities are kept below the recommended concentrations. Due to the incredibly high volume of oil that is initially being refined the scale of error that can be introduced if impurities are allowed to impact the processes can be very time consuming and costly to overcome.

Such is the importance of this testing that there are a number of oil analysis methodologies established. They continually reviewed by a number of global agencies, including the International Organization for Standardization (ISO), the American Society for Testing and Materials (ASTM) and the Society of Automotive Engineers (SAE).

Different elements are present in the oil, and can have very different effects in both the refining process and the final product. For example, when present in raw oil elements like lead, phosphorous, sulphur, nitrogen or silicon can act as poison to catalysts. Elements like arsenic, mercury and cadmium in final products are of great environmental concern. Wear metals such as copper and iron may indicate wear in an engine or any oil-wetted compartment. Boron, silicon or sodium may indicate contamination from dirt or antifreeze leading to an engine failure. Calcium, phosphorus and zinc may be used as additives so need to be analyzed for depletion since they contribute to certain key lubrication characteristics.

A range of analytical techniques that can detect these elements at very low levels is needed. And in the future industrial regulations will be requiring even lower levels to be accurately quantified.

Oils have limiting factors making the required trace analysis difficult. They have both a high viscosity and a high content of organic material, both of which can interfere with the measurements. At SciMed we can offer a range of instruments from Analytik Jena that can overcome these inherent problems. The Plasma Quant ICP-OES has the highest resolution of any current OES, and our unique technology allows the analyst to overcome the complex spectral signatures which hugely complicate the quantification of many trace signals; these unspecific spectral interferences impact on quality of the baseline fitting routines, the precision and the limits of detection.

Our unique MPO detector in our combustion elemental analyzers (the EA 5000 and CompEAct) converts interfering nitrous oxide molecules into harmless species so you can measure sulphur in the presence of nitrogen-rich compounds; essential for ASTM D4814, D6751/DIN EN 590 and DIN EN 14214 methods – they have a 10 ppm sulphur limit which is very easily exceeded if cetane improvers (which contain nitrogen) are used.