Date of Original Version
This is the author’s version of a work that was accepted for publication. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version is available at http://dx.doi.org/10.1016/j.compchemeng.2011.03.002
Abstract or Description
In this paper we address the conceptual design for the production of hydrogen from switchgrass. The process is modeled as a mixed-integer non linear programming problem (MINLP) for a superstructure embedding two different gasification technologies, direct and indirect, and two reforming modes, partial oxidation or steam reforming, gas cleaning and a water gas shift reactor (WGSR) with membrane separation is used to obtain pure hydrogen. Given the small number of structural alternatives, the problem is solved by constraining the binary variables of the MINLP so as to select each gasifier and reforming mode yielding four NLP's. Next, the energy is integrated, and finally, an economic evaluation is performed. It is shown that indirect gasification with steam reforming is the preferred technology providing higher production yields than the ones reported in the literature for hydrogen from natural gas and at a potentially lower and promising production cost 0.67$/kg.
Computers and Chemical Engineering, 35, 9, 1798-1806.