Feasibility Study on Replacement of Atmospheric Distillation Column with New Sequences in a Natural Gas Condensate Refinery Abstract   The atmospheric distillation unit is the main separation unit in crude oil and natural gas condensate refineries. An atmospheric distillation column in a natural gas condensate unit usually consists of a single column with 3 pumparounds and 2 side strippers. In this work a new column sequences have been synthesised for the first time using the modified separation matrix method and the results had been compared to other wellknown configuration through economic, exergy and exergoeconomic analysis. The results illustrate that the conventional atmospheric distillation configuration has a medium performance compared to other sequences. As an example, comparing the results obtained from the direct sequence, to the conventional distillation sequence, leads in almost 30% less annual cost, 54% less exergy loss rate and 5% more exergoeconomic factor. However, the 84.87% exergoeconomic factor for the conventional configuration could justify the application of conventional sequence in the refinery.

A MultiObjective Reactive Distillation Optimization Model for Fischerxe2x80x93Tropsch Synthesis Abstract   In the design of a reactive distillation column, aspects such as column configuration, catalyst loading, tray temperature, and side extraction rates should be well considered. Though preferences in Fischerxe2x80x93Tropsch (FT) synthesis may vary, it is acknowledged that the final product contains a wide range of hydrocarbons including fuel gas, gasoline, diesel, and linear wax. Zhang etxc2xa0al. (2018) previously developed an equationoriented framework for optimal synthesis of integrated reactive distillation systems for FT processes.  Here, we extend the mass, equilibrium, summation, and heat equations to a mathematical program with complementarity constraints to deal with possible dry trays in the nonreactive sections. The purpose of describing disappearing phases is to avoid infeasibilities due to multiple bilinear terms in the model for complicated model structures. The model is implemented by solving initialization steps and a sequence of nonlinear programming problems to determine an optimal structure and operating conditions.  Design specifications for multiple products could be set as individual objectives to determine design limits. Moreover, a balance of multiple objectives could be reached by formulating the reactive distillation model as a multiobjective optimization problem. In this work, we employ the augmented xcfxb5constraint method. The results show that significant design insights can be gained from the Paretooptimal front regarding acceptable tradeoffs among various objectives.