PEFTEC - Abstract

Abstract Information :

Mercury is a naturally occuring contaminant found in almost all oil and gas reservoirs, existing in a range of concentrations and in a number of different forms.

This causes a number of issues when the oil is processed, including corrosion and the potential for worker exposure and release to the environment. There are a number of options for removal of mercury from liquid hydrocarbons, which are predominantly focused on removal of elemental mercury. In order to understand how much mercury will be removed by a given process the mercury needs to be speciated to ascertain which forms are present. Due to the losses of mercury observed over time when samples are stored and the proven transformation of mercury from one species to another in relatively short time periods in liquid hydrocarbons, it is desirable to perform speciation analysis immediately after sampling. This limits the use of molecular speciation techniques such as GC-ICP-MS since these instrumental techniques are not portable.

The international standard test method UOP-938 allows on-site functional speciation using the physical and chemical properties of mercury species to categorise mercury as;

Elemental / soluble ionic / soluble non-ionic / insoluble.

This presentation details work carried out to better understand which mercury compounds are included in the groups labelled "soluble ionic" and "soluble non-ionic" as there is very little literature information available on this subject. This study has provided information on which compounds fall into which category, which is valuable in the evaluation of whether a removal technology will in fact remove the mercury (without having to instigate a live trial), and where the mercury can be expected to partition within the hydrocarbon processing system.