Analysis of the Possibility of Remote Laser Detection of Propane Leaks

Propane is one of the main components of the wide fraction of light hydrocarbons (WLHF). A large volume of WLHF is transported to petrochemical plants via pipelines. Control of pipelines is carried out by means of in-line pressure sensors. However, they are ineffective for detecting low-intensity leaks.To detect low-intensity propane leaks from pipelines, it is promising to use a remote laser gas analyzer installed on an aircraft.The article is devoted to the analysis of the possibilities of remote laser detection of propane leaks.Based on the data on the absorption of propane and atmospheric gases, the wavelengths of 3370 nm (in the maximum absorption of propane) and 3550 nm (in the spectral region where there is no absorption of propane) were chosen as the sounding wavelengths.It was believed that the monitoring of propane leaks is carried out by a lidar installed on the aircraft in a monostatic sensing scheme. The method of differential absorption with scattering from the earth's surface is used.To detect propane leaks, an information parameter was used, which is equal to the ratio of the power recorded by the receiver at wavelengths of 3370 nm and 3550 nm. The value of the information parameter was calculated for different heights of the propane layer on the earth's surface and different concentrations of propane in the layer.Statistical modeling was performed to quantify the effectiveness of remote detection of propane leaks.In the work, the probability of correct detection of a propane leak (detection of a leak when it is in reality) and the probability of false alarms (detection of a leak when it is not in reality) were calculated.The decision to detect propane leaks was made when the value of the information parameter was less than the threshold.The results of mathematical modeling show that for a propane content in the leak of at least 0.17 % (an order of magnitude less than the concentration limit of flame propagation), the problem of remote detection of propane leaks from the pipeline can be solved with a probability of correct detection of more than 0.999 and a probability of false alarms of less than 0.001 with a thickness of the propane layer on the earth's surface of at least 20 cm.