Effective oil in water monitoring for petrochemistry

The global crude oil production is a significant component of the worldwide economy. Each day, substantial amounts of crude oil are extracted to meet the energy demands of industries, transportation, and households globally. This crude oil is shipped, transferred, stored, and processed by refineries into over a thousand different petroleum products. During this intensive processing, it is likely that some oils may enter wastewater streams. To prevent this, there is a considerable demand for reliable and rapid online Oil-in-Water (OiW) analysers.

While a variety of these online OiW process analysers are available, most measure only one of the properties of oily compounds and not all types of oils and fats. Additionally, these measurements are indirect, meaning that the results must be correlated with the corresponding laboratory OiW method (EN-ISO 9377-2). This is particularly challenging when the composition of OiW varies and contains a mixture of various unknown oil types! However, the QuickTOCultra analyser by Process Insights measures all types of oil, regardless of whether they are of mineral, plant, or animal origin. It is a carbon counter that registers all hydrocarbons.

Most online OiW analysis methods are based on indirect measurements, meaning that the consistency, composition, and origin of the oil influence the results. Therefore, correlation with the corresponding laboratory OiW method (EN-ISO 9377-2) is required. This is particularly challenging when the OiW composition varies and includes a mixture of various unknown oil types! In contrast, the QuickTOCultra provides a direct OiW analysis and measures all types of oils, fats, and lubricants regardless of their origin, via carbon counting. It is a summation parameter analysis that responds to all organic hydrocarbon species.

To protect microorganisms in wastewater treatment plants, effective monitoring of wastewater effluents is essential. Specialised OiW analysis systems have been developed to account for the diversity of oil types present in wastewater and enable comprehensive monitoring. Wastewater contamination can be caused by several products with varying compositions depending on the loading and leaching activities taking place. Online OiW analysers that cannot respond to all these oil types and wastewater compositions and rely on indirect measurement techniques are entirely impractical, and correlation with a laboratory analysis method would be impossible.

Many available Total Organic Carbon (TOC) analysers are not necessarily suitable for oily applications. Firstly, parts that come into contact with the sample are continuously contaminated. Secondly, oil is hydrophobic: oil and water do not mix. Finally, most TOC analysers have a limited measurement range of up to 2,000 mg C/liter, and dilution cannot be used to achieve higher ranges, as this is an unsuitable technique for oily samples. The particularly refined QuickTOCultra process analyser, manufactured by Process Insights, employs a remarkably easy-to-understand design that proves to be suitable. Maintenance is drastically reduced as it uses a processor-controlled XY-controlled robotic arrangement that mimics manual laboratory methodology. The XY robot sequentially positions an injection needle into a sample overflow vessel, the injection port of the 1200ºC reactor, or a waste vessel, where the oils and fats in the sample are fully oxidized. Oil tends to adhere to wetted parts, and over time, an analyzer becomes contaminated, causing so-called memory effects and systematically measuring relatively clean samples as too high. The significant advantage of the QuickTOCultra is that only the injection needle can become contaminated, which is rinsed with (hot) rinse water immediately after sample injection.

A well-designed sample extraction system is crucial. The analyser has to be optimally placed as close as possible to the wastewater stream, where e.g. a submersible propeller pump installed generates a high-speed water flow through the 1 ½" quick sample loop to the analyser. Using the so-called anti-kinetic fluid dynamics principle, the FlowSampler extracts the sample. No sample preparation is required as, at high speed, large, heavy, and solid particles tend to remain in the main flow, extracting only liquids. No sample conditioning is required, such as a filter.

Process Insights' QuickTOCultra offers an effective solution for oil in water monitoring by enabling direct analysis and covering a variety of oil types. With a dynamic measurement range and robust sample extraction system, the QuickTOCultra is ideal for petrochemical applications.