Performance of a Carboxydothermus hydrogenoformansimmobilizing membrane reactor for syngas upgrading into hydrogen

  1. Get@NRC: Performance of a Carboxydothermus hydrogenoformansimmobilizing membrane reactor for syngas upgrading into hydrogen (Opens in a new window)
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Journal titleInternational Journal of Hydrogen Energy
Pages21672175; # of pages: 9
SubjectAbiotic membranes; Carboxydothermus hydrogenoformans; CO conversion; Co loading; Dissolved co; Hollow fiber membrane bioreactor; Hollow fiber membranes; Liquid velocities; Low concentrations; Membrane bioreactor; Membrane permeability; Membrane reactor; Operational conditions; Pure culture; Reactor performance; Sessile growths; Shearing stress; Shell-side; Syn-gas; Three orders of magnitude; Total biomass; Transfer rates; Volatile suspended solids; Biofilms; Bioreactors; Carbon monoxide; Fischer-Tropsch synthesis; Fouling; Hydrogen; Internet protocols; Liquids; Loading; Mass transfer; Membrane fouling; Synthesis gas; Membranes
AbstractHydrogen conversion of CO by a pure culture of Carboxydothermus hydrogenoformans was investigated and optimized in a lab-scale hollow fiber membrane bioreactor (HFMBR). The reactor was operated under strict anaerobic, extremely thermophilic (70 °C) conditions with a continuous supply of gas, for four months. Reactor performance was evaluated under various operational conditions, such as liquid velocity (vliq) (13, 65 and 130 m h -1), temperature (70, 65, and 60 °C), CO pressure (from 1 to 2.5 atm) and CO loading rate (from 1.3 to 16:5 mol Lrxr -1 d-1). Overall, results indicated a relatively constant H2 yield of 92 ± 4% (mol mol-1) regardless of the operational condition tested. Permeation across the colonized membrane was improved by three orders of magnitude as compared to the abiotic membrane, because of dissolved CO concentration was constantly maintained low in the liquid on the shell side of the membrane as continually depleted by the microorganisms. Once the biofilm was sufficiently developed, a maximum CO conversion activity of 0.44 mol CO g-1 volatile suspended solid (VSS) d-1 was achieved at a pCO of 2 atm or above and a vliq of 65 m h-1. However, this highest activity represented only 15% of the maximal activity potential of the strain under non-limiting conditions, attributed to the low concentration of dissolved CO (0.01-0.07 mM) present in the HFMBR liquid. Higher vliq (130 m h-1) produced shearing stress, which detached a significant portion of the biofilm from the membrane, and/or prevented less sessile growth (57% total biomass as biofilm, as opposed to 84-86% at lower vliq). One may deduce from this work that the volumetric CO conversion performance of such a membrane bioreactor would be at the most in the range of 5 mol CO Lrxr -1 d-1. Overall, the CO conversion performance in the HFMBR was biokinetically limited, when not limited by gaseliquid mass transfer. Additionally, over time, membrane fouling and aging decreased membrane permeability such that the CO transfer rate would be the most limiting factor in the long run. Crown Copyright © 2012, Hydrogen Energy Publications, LLC.
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AffiliationNational Research Council Canada (NRC-CNRC); Energy, Mining and Environment (EME-EME)
Peer reviewedYes
NPARC number21269826
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Record identifier11ee5c87-3f45-4b5a-b6ae-db5ebe37ffe2
Record created2013-12-13
Record modified2016-05-09
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