Experimental Study On Measuring Grease Thickness In Petroleum Pipelines By Using Fast Neutron

In this paper, the response relation by theoretical and experimental research between neutron counts and grease thickness by polyethylene simulated was studied by using 241Am-Be neutron source in based on a large number of literature. It has been discovered that there is a good linear relationship between the logarithm of reciprocal with neutron transmission rate and the grease stain thickness with high sensitivity and detection accuracy. By using transmission neutron Monte-Carlo simulations have been carried out the impact of sensitivity and neutron counts with different geometries about source distance. The research found that there is influence about measurement sensitivity and accuracy with source distance under different situation.The greater sensitivity and better accuracy with smaller source distance. But effect of accuracy is smaller; the accuracy can fulfill the mm level of actual measurement.Most of the insulation thermal layers are organic materials. Hydrogen is rich in insulation thermal layer. The influence of the thermal insulation layer has studied. The experiment results show that there are some effects, and the influence is obvious by using the fast neutron scattering method than transmission. It must calibrate the neutron counts of thickness with Omm when measure the thickness of grease using fast neutron scattering method. The purpose is to determine the relative neutron counting.The relative scattering counting should use the quadratic multinomial calibrate in the scattering method to thicker insulation thermal layer. It increases measuring range of grease to the benefit of measurement of thicker.Soil quantity that was digged is different using same cross section method and the same axis method. Through the experiments and Monte-Carlo simulation calculation found that the same cross-sectional method is better than the same axis method in terms of neutron counting, sensitivity or measuring accuracy. Large scattering angle is better than small scattering angle, in actual measurement. The angle more than 90°should be used in same cross-section method. This can reduce the mining quantity soil that was digged.Finally,discusses the feasibility using PGNAA to detect thickness of grease with pipeline. Paper put forward the corresponding proposal of detection about the grease thickness of pipeline using fast neutron in further development.This work is the principle research of testing grease stain thickness by using fast neutron and it provides solutions guidance and experimental basis for manufacturing detector of measurement grease instrument with surface nondestructive using fast neutron...