Contaminants from refining processes

Waste-derived fuels from refining processes Fuels produced by refining oil-bearing hazardous wastes with normal process streams at petroleum refining facilities are exempt if such wastes resulted from normal petroleum refining, production, and transportation practices. For these wastes to be considered as refined, they must be inserted into a part of the process designed to remove contaminants. This would typically mean insertion prior to distillation. 

TABLE 2-6. Common Fuel Contaminants Resulting from Refining Processes... 

The view at Cadmium changed with time starting from a valuable resource and ending up as a toxic element with a limited number of applications not substituted by alternative products. The decontamination of the technosphere works to a certain extent. Due to the character of Cd as trace contamination of phosphate fertilizers and of Zn ores and fossil fuels, there is no final solution for the environmental contamination. Due to the restrictions issued in many countries, there is reason to fear that Cd could end up in unknown material streams. From an analysis of the refining of Zn ores in 2002, it has been concluded that about one quarter of Cd generated as by-product ( 7,000-8,000 Mg) could not be found either in the products analyzed or in the emissions from the process [27]. 

FERROSEP A magnetic process for removing iron contaminants from petroleum residues before desulfurization. Developed by Nippon Oil Company and Nippon Petroleum Refining... 

Crude oil contains a number of metallic elements which are of interest either due to the undesirable effects they cause in the refining process or as an indication of the origin of the oil. The concentration levels encountered will vary with the type of crude oil. Crudes originating from different oil fields may vary markedly in trace-metal content. Also some crude oils will become contaminated in transport from the oil well to the refinery by, for example, pipeline material or seawater. The levels of such metals as Ni, V and Na must be carefully controlled in order to reduce production problems such as plant corrosion or catalyst poisoning. 

It transpired that the toxic oil was rapeseed oil that had been adulterated by the addition of 2 per cent of a chemical called aniline, as required by law in Spain for imported rapeseed oil so that it cannot be used for cooking. This oil had been refined and was sold for human consumption, as had been done before without adverse effects. It would appear that a batch of oil may have been refined differently or somehow became contaminated. The toxic oil was found to come from only one source within a particular refinery. The Spanish government agreed to replace the suspect oil with pure olive oil, after which the number of new cases subsided. Collection of contaminated oils known to be associated with the syndrome for analysis was a difficult task due to the government exchange programme. The results showed that the oil associated with the syndrome had a similar composition to rapeseed oil and contained contaminants as a result of the added aniline and the subsequent refining process. 

Trace elemental analysis can also be used to indicate the level of contamination of middle distillate fuels, e.g. turbine fuels. Metal contamination can cause corrosion and deposition on turbine components at elevated temperatures. Some diesel fuels have specification limits to guard against engine deposits, however they sometimes employ Mo or Ni as a catalyst for the refining process which eventually ends up in the finished products. There are several sources of multi-elemental contamination in naval distillate fuels. Sea water is pumped into the diesel tanks as ballast to immerse ships and submarines. Some oil transport ships have dirty tanks and contamination and corrosive products can also come from piping, linings and heat exchangers. 

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