Acoustic signal processing with robust machine learning algorithm for improved monitoring of particulate solid materials in a gas pipelineThe flow of particulate solid materials in a gas pipeline can significantly erode mechanical equipment, and hence, real-time quantitative monitoring is a timely need for the oil and gas industry. Although a considerable amount of research has been conducted employing acoustic signals for qualitative monitoring, there is still an unmet demand for a simple and robust quantitative monitoring system. Acoustic signal processing with machine learning is a simple and robust method that has the potential to meet this demand, but has not been previously used for particulate solid material quantitative monitoring. Here we report on the development of acoustic signal processing methods strictly on the existence and the significance of the correlation between emitted acoustic signals and the flow conditions and behaviours of particle-laden gas pipeline. The integrated, conventional Artificial Neural Network (ANN) models are used to capture the distribution of the acoustic feature vectors extracted from the signal processing techniques. The backpropagation learning method coupled with Grey wolf optimiser is used to adjust the weights of the network to minimize the regularized cost function for each feature vector. The Grey wolf optimiser is used to provide global adaptation strategy for the network hyper-parameters. The results from the signal processing techniques demonstrate a significant qualitative association between flow conditions and the emitted acoustic signature. Further, conventional ANN has mainly been concerned with capturing systematic patterns in a distribution of measurements fixed in time and the results of the processes are collected in discrete time intervals. Therefore, a modification of the classical ANN, called the Time Delay Neural Networks (TDNN) is used to capture such dynamics. The proposed method compares the performance of the classical ANN models with the TDNN models wherein the feature vectors were used to train the TDNN models.Results show that the TDNN models outperform the classical ANN models which confirm the fact that classical ANN models are insufficient for processing these time sequences. Overall, this study lays the basis for employing signal processing techniques in the development of a real-time quantitative particulate solid monitoring in a gas pipeline.