ASTM D4929 is the Standard Test Method for Determination of Organic Chlorine Content in Crude Oil
Organic chlorines do not occur naturally in crude oil. When present, they result from contamination in some manner, such as disposal of chlorinated solvent used in many dewaxing pipeline or other equipment operations.
Organic Chlorine species are potentially damaging to refinery processes. Hydrochloric acid can be produced in hydrotreating or reforming reactors and the acid accumulates in condensing regions of the refinery. Unexpected concentrations of organic chlorides cannot be effectively neutralized and damage can result. Organic chlorides are not known to be naturally present in crude oils and usually result from cleaning operations at producing sites, pipelines, or tanks. It is important for the oil industry to have common methods available for the determination of organic chlorides in crude oil, particularly when transfer of custody is involved.
Organic Chlorine present in the crude oil (for example, methylene chloride, perchloroethylene, etc.) is usually distilled into the naphtha fraction. Some compounds break down during fractionation and produce hydrochloric acid, which has a corrosive effect. Some compounds survive fractionation and are destroyed during hydro-treating (desulfurization of the naphtha).
Other halides can also be used for dewaxing crude oil; in such cases, any organic halides will have similar impact on the refining operations as the organic Chlorines.
ASTM D4929 method Procedure B covers the determination of organic Chlorine in the washed naphtha fraction of crude oil by oxidative combustion followed by microcoulometric titration.
The presence of chlorine in crude oil can hydrolyze during the refinery process to form hydrochloric acid which causes corrosion. Corrosion at petroleum refineries is a critical problem which exists at many places around the globe and has a huge cost impact in terms of maintenance.
Therefore, an effective chloride monitoring solution should be implemented and many refineries have a periodic testing of inorganic chlorides in place. A well-known, reliable and sensitive test method for the chlorine analysis in crude and fuel oil products is oxidative micro coulometric technique which has been applicable at the EST and TSHR Total Chlorine analyzer, model NEXIS TX.
Waste generated by agro-food industries can result in environmental contamination and impact the costs involved in controlling and reducing this harmful environmental effect through stringent legislations. The generation of bio-energy and availability of renewable fuels as a biodegradable source will help to lighten the environmental pollution grade and have already been introduced and implemented in many countries. Exhaust emissions of sulfur oxides, nitrogen oxides, carbon monoxide and unburned hydrocarbons are significantly lower with biodiesel usage in comparison to mineral diesel, which can dramatically reduce the impact on the environmental. The presence of chlorinated compounds in these types of products can negatively affect the lifespan and effectiveness of catalyst material used in the process of biodiesel production. The regular chlorine concentrations of the refined biodiesel and animal fat raw materials are at trace ppm level, which are determined quantitatively by oxidative combustion micro-coulometric detection technique. This Application Note describes the principle, procedure and performance data of a Total Chlorine analysis in original/raw animal fat samples using the EST and TSHR NEXIS TX Analyzer in accordance with ASTM D4929
To comply with ASTM D4929, EST & TSHR offer the NEXIS TX model and TX 6000/7000 with oxidative micro coulometric titration including combined instrument configurations like TN/TX and TS/TX models with automatic liquids injection through the AS120 Liquids Autosampler configuration for trace level Total Chlorine analysis.