Increasing twins pressure of environmental and legislation have resulted in changing the approach of traditional design to consider the multi-objective sustainable design in chemical processes.This paper focuses on the phenol-ammonia wastewater stripping section in a coal to synthetic natural gas (SNG) plant.Comparison between the single pressurized tower with side-draw design and double pressurized tower design shows the first design benefits from lower economic cost at the expense of low sustainability.On such basis

three key decision variables are selected

including total number of stages

side-draw position and heat feed stream temperature to minimize the total annualized cost (TAC) and potential environment impact (PEI) metric.The optimal solution reveals that the single pressurized tower with side-draw design has potential to achieve low economic costs and high environmental performance simultaneously by changing the operating conditions.