Enhanced hydrogen production with carbon storage by olivine alteration in CO 2 -rich hydrothermal environments

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4 Citations (Scopus)

Abstract

Here we report a novel experimental study on simultaneous hydrogen (H 2 ) production and CO 2 storage. A high concentration of NaHCO 3 (source of CO 2 ) is utilized to promote H 2 generation from olivine (Mg,Fe) 2 SiO 4 ) hydration, and then CO 2 is reduced to formic acid (HCOOH) or sequestrated in magnesite (MgCO 3 ) in a hydrothermal system. The effects of NaHCO 3 concentration (0-1.0 mol/L) and initial pH (8-11) on H 2 production and CO 2 storage were experimentally lab-scale tested at 300 °C. Both reaction pathways and reaction rates changed with variation of the reaction conditions. Under CO 2 -rich conditions, olivine consumption was promoted with the absence of Fe(II)-bearing brucite (Mg,Fe(OH) 2 ), by which more Mg and Fe ions were released. Thus, the production of H 2 and carbonation processes were significantly accelerated. The highest H 2 generation rate reached 3.13 mmol/kg olivine ·h, which is more than 15 times higher than previously reported. The HCOOH yield was 129.1 mmol/kg olivine and magnesite ((Mg,Fe)CO 3 ) generation reached a maximum of 19.2 wt% in 72 h. The enhancement of H 2 production at lower pH is primarily attributed to the presence of HCO 3 - , rather than the pH changes caused by NaHCO 3 addition. The system proposed here has significant potential to be applied at the field-scale.

Original languageEnglish
Pages (from-to)205-213
Number of pages9
JournalJournal of CO2 Utilization
Volume30
DOIs
Publication statusPublished - 2019 Mar

Keywords

  • CO -rich
  • CO reduction
  • H production
  • Hydrothermal
  • Olivine alteration

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Waste Management and Disposal
  • Process Chemistry and Technology

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