Laser Based Detection of Paraffin in Crude Oil Samples: Numerical and Experimental Study

A laser spectroscope was used to detect paraffin in paraffin contaminated oil samples. After passing through the oil sample, the laser light was detected by using a semi-conductor photodiode, which in turn converts the light signal into electric voltage. The samples studied have paraffin concentrations ranging from 20-60% wt and a thickness of 1-10 mm. The results showed a good agreement with Beer Lambert's Law for the attenuation of light. A 1-D mathematical model based on energy balance and describing the process of laser radiation attenuation within the oil sample was developed and numerically solved. The model was used to predict the net laser light and the amount of light absorbed per unit volume at any point within the oil sample. The results of the numerical model were found to be in correlation with those obtained from the experiments. The mathematical model presented was then used for different types of oil products to determine the local rate of absorption in an oil layer under different working conditions. Most of the factors affecting the light absorption were considered. The effects of the angle of incidence, bottom reflectivity, and layer depth are presented and discussed.