Sensibility Analysis of Pre-cooling Cold Box Pipeline Blockage in DMR Liquefaction Process

As the key equipment of onshore and offshore natural gas liquefaction (LNG) plants, the performance of cold box influences operation reliability of the whole system. Due to the fact that the temperature of pre-cooling cold box is much lower, its pipelines can be blocked by the hydrates. In this paper, a dynamic model of dual mixed refrigerant (DMR) liquefaction process is established. The variations of gas-phase and liquid-phase plugging ratios are selected as disturbances to test the dynamic responses of the DMR liquefaction process. In addition, an experimental device of DMR liquefaction process is constructed to verify the accuracy of dynamic model. The results show that the process parameters from dynamic model agree well with the experimental data. When the plugging ratio of liquid-phase pipeline is more than 21.75% or plugging ratio of gas-phase pipeline is more than 29%, control structures of DMR liquefaction process fail. (C) 2017 The Authors. Published by Elsevier Ltd.