Addition/Correction Cite This: Ind. Eng. Chem. Res. 2018, 57, 1763−1766
pubs.acs.org/IECR
Correction to “Optimization of a Pressure Swing Adsorption Process for Nitrogen Rejection from Natural Gas” Surya Effendy,† Chen Xu, and Shamsuzzaman Farooq* Department of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 Singapore
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Ind. Eng. Chem. Res., 2017, 56, 5417−5431 (DOI: 10.1021/acs.iecr.7b00513). OVERVIEW In the paper “Optimization of a Pressure Swing Adsorption Process for Nitrogen Rejection from Natural Gas”,1 the method of orthogonal collocation with even Legendre polynomial basis functions and Dirac delta weighting functions was used to solve for the transport of methane/nitrogen in micropores of a carbon molecular sieve. While extending the model to a methane/ nitrogen/carbon dioxide mixture, it was observed that this numerical method does not guarantee mass conservation. It gives inconsistent results when the chemical potential driving force (CPDF) model for the concentration dependence of micropore diffusivity is applied beyond a certain pressure range as the saturation limit is approached. It does not become evident from the overall mass balance at cyclic steady state within a cycle until the third component is added, which is the why it remained undetected in the two-component study. An appropriate correction is adapted from the work of Serbezov and Sotirchos.2 In brief, one of the weighing functions of the orthogonal collocation method is replaced with a Galerkintype function, which conserves mass. The method is found to be stable at pressures in excess of 20 bar, in contrast to the results published in our original paper,1 and yields the same result as the previous method for pressures of
