The effect of material flow uncertainties on the overall economic performance of a typical gas processing plant (GPP) under various upstream conditions

Uncertainty is an inherent characteristic of any chemical process plant. It has a profound effect especially for gas processing plant as its feeds are normally originated from different upstream production facilities. Due to this, the plant is usually subject to a continuous variation in upstream conditions, such as temperature, pressure, flow rate and composition. These variations in turn propagate throughout the plant and affect not only the normal operating conditions but also the product specification. This work presents on how the material flow uncertainties from the plant’s inlet and outlet affects the overall economic performance. Accordingly, two chance constrained optimization models were developed by separately taking the uncertainties from both sides of the plant. The developed models were tested using case studies for an existing gas processing plant. The trade-off between profit and reliability of holding the process constraint were analyzed by solving the problem at certain confidence level. The confidence level is a user-defined variable assigned to hold the constraints beginning from 50% to 100%. Result shows that the optimal profit change for material flow uncertainty from the plant inlet is 86%. However, for the uncertainty from the plant outlet, the optimal profit change is only 2% for the same confidence interval [96% - 100%]. The result indicates that uncertainty from the plant inlet has a significant impact in terms of overall economic performance compared to the plant outlet.