This project was a part of a larger collaborative research on real-time optimization (RTO) of a Hydrodesulphurization (HDS) plant which is normally cascaded with the control system. An RTO system optimizes the plant performance by adjusting the setpoints of the closed loop controller in real-time, i.e. during the operation of the plant. To achieve the benefits of the RTO system it is required that the control system provides an acceptable performance to eliminate oscillations and transient errors as much as possible. In this project, the model predictive control algorithm was utilized for this purpose.