Reliable Oil-in-Water Analysis

Nowadays the world's crude oil production is over 72,000,000 barrels per day. This crude is shipped, transferred, stored and processed by refineries into over a thousand different mineral oil products. During intensive processing it is likely that some oils may leak into the waste water. To prevent this, there is a great need for reliable rapid online Oil-in-Water (OIW) analysers.

There are many oil-in-water analysers available on the market. However, most of these analysers are based upon indirect measurement methods that need to be correlated to the applicable oil-in-water laboratory method. The fluorescence method for instance measures petroleum oils. The measuring result of the photometer scattering method, on the other hand, depends mainly on the amount and size of oil droplets. The UV absorption method though makes use of the phenomena that hydrocarbons absorb light at specific wave lengths. Hence, these analysers are not able to measure all types of oil, as they are developed for specific usage and for certain applications.

On the other hand, Total Organic Carbon analysers (TOC) measure all types of oil, independently of their composition, state or origin. It is a direct sum parameter method, responding to all organic hydrocarbon species. As a matter of fact a TOC analyser is a carbon counter. It responds to all hydrocarbons and hence to all oils. For the majority of applications there is no need of a selective analysis as there are no other hydrocarbons present.

However, not all TOC analysers are suitable for oily applications. The sticky oil sample easily contaminates analyser parts, causing memory effects and as a result relatively clean samples are systematically measured as being too high. Most analysers have a limited measurement range of up to 2,000 mg/l C. Higher ranges are only achieved by use of sample dilution, which is obviously an intolerable technique for oily samples.

The LAR (UK) QuickTOC_ultra analyser offers a solid solution for challenging oil-in-water applications. The QuickTOC_ultra has the great advantage that only the injection needle can get contaminated by the oils in the sample. Since it is flushed instantaneously after every sample injection, any carry over and memory effects are minimised. Furthermore, the QuickTOC_ultra is able to measure ranges from 10 up to 50,000 mg/l TOC, without using dilution or other pretreatment techniques.

This analyser supports factories and refineries in their crucial need for a dependable online solution that is able to provide accurate concentration readings of such a complicated compound like oil. Worldwide, thousands of LAR analysers and in particular the Quick-Series are successfully in operation.