Determination of Water & Oil Contents of Oil Sludge by Online Two-dimensional NMR

Oil sludge is one of the major pollutant of petrochemical industry, which is inevitably produced in numerous petroleum processing operations, such as oil production, transportation, storage, and refining. To understand the water & oil contents of oil sludge is important for the method selections and process designs in oil sludge treatment. Compared with conventional laboratory water & oil contents analytical methods (Dean-Stark azeotropic distillation method, Karl Fischer titration, Soxhlet extraction, distillation and optical method etc), the NMR methods has the following advantages: accurate and repeatable measurements, not affected by salinity, density, electrical conductivity, emulsion consistency, gas component, vapour component and solids component, rapid and non-destructive detection [1] [2] .
In this study, online two-dimensional (2D) NMR with DEFIR pulse sequence [3] is used as a tool for rapid (less than 10 seconds for each sample) distinguish the components of oil sludge, and then combined the measured 2D distributions with the partial least-squares (PLS) regression models, successfully realized rapid accurately quantify the water & oil content of oil sludge.
We apply this method to a portable NMR analyzer system which can be conveniently used in the site of petroleum industry and realized on-site and on-line component analysis of oil sludge.

Detection of Fluid Molecular Structure using 2D NMR: (a) Portable NMR analyzer; (b) DEFIR decay curves recorded for ten oil sludge samples; (c)Inverted 2D T1-T2 maps; (d)Relationship between measured and NMR predicted results.