Optimization of heat exchanger network in the dehydration process using utility pinch analysis

Pinch analysis was applied to optimize the heat exchange network used in the moisture removal processes of energy plants. The moisture removal process absorbs moisture from natural gas using glycol as an absorbent, and the recycling process then separates moisture from the H2O-rich glycol in a regenerator column by applying the principle of vapor-liquid equilibria. For the dehydration process of a natural gas plant, the heat and mass flows are properly established and calculated by means of a static process model for a utility system embedded in the process based on the properties of natural gas. The results of the calculation generate a T-H composite curve that can be used to compare the pinch and to assess the installation and operating costs for the target temperature. The results show that approximately 61% of the total heat supply can be replaced with low-pressure steam, depending on the optimization of the heat exchanger network of the moisture removal process. Further, the annual operating costs can be reduced by about 17% in this case.