Analysis and control of a partially heat integrated refinery debutanizer

In this contribution, the internal heat integration concept has been applied on a commercial refinery debutanizer column for the separation of an eight-component hydrocarbon mixture. Here, the thermodynamic feasibility of this process has been identified. Then, an economically interesting partially heat integrated debutanizer column (HIDBC) configuration is explored. A sensitivity test has been conducted to select the compression ratio required to meet the product specification. This study deals with the parametric analysis to investigate the effect of important parameters on product purity and energy consumption. An economic comparison between the conventional debutanizer and the proposed thermally coupled debutanizer scheme is also performed. This paper proposes a control algorithm that considers the control of most sensitive tray temperatures. The singular-value decomposition (SVD) method is used for selecting the sensitive trays. Finally, the closed-loop control performance of the HIDBC has been examined. Due to the internal energy integration, better performance is achieved with up to 44% energy saving and more than 14% saving in total annual cost.