Design of experiments (DOE) for adsorptive desulfurization (ADS) of liquid fuels – A review

Abstract

Air pollution and acid rain are burning issues. Environmental science helps analyse these issues and find appropriate solutions. Organic sulfur compounds present in the liquid fuels are the root cause of air pollution and acid rain. Refineries are using hydrodesulfurization (HDS) as a conventional technique of sulfur reduction, from liquid fuels. However, there are challenges associated with it. Hence, alternative techniques are gaining attention. Adsorptive desulfurization (ADS) is emerging as a low-cost alternative to conventional process. Sulfur removal occurs through physical or chemical adsorption. A variety of adsorbents including activated carbons and zeolites have been tested. Regeneration and reuse of spent adsorbents also studied. Many experimental runs will be required at each stage in order to draw accurate conclusions and optimize the parameters involved. Through design of experiments (DOE), number of runs can be reduced. Main parameters can be optimized. In addition, the main effect of parameters on sulfur removal along with their interactions affecting sulfur reduction, positively or negatively, can be investigated. Present paper reviews the methods for DOE for ADS of liquid fuels. The paper also generates data from reported models and fits it to various isotherms. Present authors used Microsoft Excel® as an affordable tool for analysing the reported data and obtain models similar to the one reported. The development of low cost and green adsorbent is the key to commercialization of ADS.