Sulphur Analysis in Aromatic and Naphtha Hydrocarbon Stream of Petroleum Products and Crude Oil - 5 Pages

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Catalogue excerpts

Sulphur analysis in aromatic and Naphtha hydrocarbon stream of petroleum products and crude oil Bushra Dawood, Application Coordinator C.I. Analytics Nowadays, top priority of petrochemical industries is to detect impurities at extremely low levels to conform to stringent government regulations, protecting expensive catalysts, and ensuring product quality. This article describes and compares different method of analysis to quantify elemental impurities in petrochemical products. Findings revealed that Hydrogenolysis and Rateometric Colorimetry (ASTM 4045) best suits the application requirement of petroleum industry. Introduction Crude oil is a complex mixture of different hydrocarbons that varies in appearance and composition depending on the geographical environment. Major constituents in oil, gasoline, diesel, and a variety of solvents are mostly hydrocarbons. Fluid catalytic cracking of petroleum fractions in oil refineries yields three categories of crude oil: paraffinic, naphthenic and aromatic. The mixture can be separated by distillation and gravity. Its composition consists of carbon, hydrogen, sulphur, Nitrogen, oxygen, metals as complexes and salts. Sulphur is the third most abundant element in crude oil and must be removed due to its corrosive property, intolerable odour and harmful combination to sulphur dioxide (SO2) and hydrogen sulphide (H2S). There are two types of crude oil, one that is “sour” containing high amounts of sulphur or sulphur compounds and the second type is “sweet” containing lower sulphur amounts or sulphur compounds. The types of sulphur that can be present in crude oil are sulphides, disulfides, mercaptans, thiophenes, etc. There is a highly competitive business in petroleum constituents including aromatic hydrocarbons such as (benzene, toluene, ethylbenzene, and xylenes, also known as BTEX), polynuclear aromatic

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hydrocarbons (PAH) and Naphthenes. Catalysts used in the Polymerization industry are highly selective and sensitive. These expensive catalysts can be damaged by impurities during the oil refining process. Replacing these catalysts can be very complex, expensive and can eventually lead to loss in business. Hence, impurity analysis has become crucial in this industry. Manufacturers must be able to accurately detect and measure sulphur impurities at very low levels to aid in detecting problems before they occur. Sulphur measurement as an impurity in hydrocarbon streams Numerous methods can be used...

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Inductively coupled plasma atomic emission spectrometry, ICP-AES This is a widely used method that implies energy emission of an element at its explicit wavelength i.e., plasma excitation and emission. In this process argon gas is used to avoid combustion at extremely high temperature. This test method is started with samples preparation, and if needed sample is treated with acids, heated or microwave digested. Subsequently, water is excluded from the stream, whereas remaining sample is converted to gaseous phase. A nebulizer is used to convert the liquid sample into aerosol. Upon exposure to...

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a measurable color change of the paper. When the Sensi-tape is exposed to the sample a reaction occurs instantaneously and visible results can be observed immediately. This change in color is directly proportional to the concentration of the impurity in the sample stream. The stain on the Sensi-tape is read by a photo-optical system and compared to a calibration curve. This measurement technique is fast, extremely sensitive and exceptionally specific. Tape-detection method detects toxic gases at PPB detection levels. It does not react to other substances found in the process so there is virtually...

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Two available methods are used to obtain H2S from an organic hydrocarbon mix: Reductive pyrolysis: Reaction occurs between excess hydrogen and organically bound sulphur in a mixture of hydrocarbon stream at high temperature, products such as H2S and methane are obtained. Oxidation and reductive pyrolysis: Reaction between air and organically bound sulphur in a mixture of hydrocarbon stream at high temperature generates products such as SO2, SO3, CO2 and H2O. In the second part of this reaction SO2, SO3 are exposed to hydrogen thereby H2S is obtained. This method helps prevent coking problem. Dry...

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