A potentially fast approach for detecting wax appearance temperature and quantification in crude oils using optical back scattering analysis

Conventional methods for determining Wax Appearance Point (WAP) and wax content in crude oils—such as differential scanning calorimetry (DSC), rheology, and modified acetone precipitation (SY/T 7550–2000)—offer established reliability but face challenges with complexity, sensitivity, and operational ease. This study introduces Back Scattered Light (BSL) analysis method as alternative that is rapid, non-invasive and leverages wax particles’ unique scattering properties. Using BSL, WAPs were accurately measured for six crude oil samples (YM, YD, SHB, XJN, YQ, GD) at temperatures between 16°C and 48°C. The method was validated using samples YD and YM whose results were compared with the coventional methods. The BSL method showed great accuracy, achieving a 1–5 % error margin for WAP. Unlike classical methods, BSL ably identified the two WAPs in YM (47°C and 36.33°C), corresponding to distinct paraffin and microcrystalline wax types that were confirmed with optical microscopy. Wax content estimations of 20.29 % (YD) and 35.12 % (YM) were consistent with DSC and SY/T 7550–2000 within a 5 % margin. Experiments with commercial wax in heptane showed BSL’s sensitivity to both macro- and microcrystalline wax types. The BSL method’s reduced sample requirements, shorter testing times, and ease of operation make it a compelling alternative to traditional approaches, with significant potential for enhancing sustainable wax management in crude oil processing.