A new small leakage detection method based on capacitance array sensor for underground oil tank

Abstract

The early detection and discovery of small leakages from underground storage tanks (USTs) is an effective means for preventing the spread of contamination to deep soil and groundwater, which is of great significance to the process safety and risk management of oil tanks. In the previous studies, the soil sample collecting by these boreholes near the oil tank, the detection results have a certain degree of randomness and non-timeliness due to the sampling affected by the distribution of the boreholes, which would result in failure to catch small leakages of UST in time. According to capacitance sensor having a sensible capacity for relative permittivity of the soil, we propose a new small leakage detection method that employs the full-coverage three-dimensional capacitance array sensor with optimized parameters and higher sensitivity and our established measurement function of oil leakage to realize early detection of small leakage. Such a method can effectively solve the problems of incomplete sampling and easy to miss small leaks in borehole sampling detection. In addition, the experimental results show that the absolute error is less than 0.110% when selecting the small oil leakage in the range of 0.068~3.261%. Therefore, our method has higher measurement accuracy and could offer an efficient way for early discovery and quantitative estimation of small oil leakages from UST, which would provide a reliable basis for process safety and risk prediction.