The most common method of removing acid gases from natural gas is through the use of solvent-based gas sweetening plants, which are energy-intensive. The present study aims to establish a plant-wide structure to operate natural gas sweetening plants optimally. Thus, a steady-state simulation of the Khangiran plant was carried out, and a 17% reduction in energy usage was achieved as a result of the optimization by the application of surrogate models. The self-optimizing method was applied to find the best set of controlled variables (CVs). There was found one unconstrained degree of freedom (DOF). The best CV for the remaining DOF was found to be the top stage temperature of the regenerator. Aspen Plus Dynamics was used to examine the performance of the proposed control structure utilizing simple traditional PIDs and compare it to modern feedback and feedforward MPCs.

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