Life cycle assessment of CO 2 sequestration in magnesium silicate rock - A comparative study

Experience Nduagu*, Joule Bergerson, Ron Zevenhoven

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    47 Citations (Scopus)

    Abstract

    This paper addresses the energy and environmental implications of sequestrating CO 2 from a coal power plant using magnesium silicate rock. An accounting type life cycle assessment (LCA) of the mineralization method under development at bo Akademi University (AU), Finland, is presented and the results are compared with the process developed at the National Energy Technology Laboratory (NETL), formerly Albany Research Council (ARC) in the US. The AU process is a multi-staged route where CO 2 is sequestered via a process that first produces magnesium hydroxide, Mg(OH) 2 from Mg silicate. The Mg(OH) 2 produced is later reacted with CO 2 in a high temperature gas/solid pressurized fluidized bed (FB) reactor, forming pure, stable and environmentally benign MgCO 3 product. This study addresses the following important issues; (a) the material and energy requirements of sequestering 1 ton of CO 2 (t-CO 2) in mineral silicate, (b) the overall environmental burdens associated with CO 2 sequestration using serpentinite mineral, (c) the priorities and opportunities for reduction of energy requirements and environmental impacts associated with mineralizing CO 2, and (d) comparison of LCA results of the AU mineralization process route with that of the mineralization process developed by NETL. Exergy calculations show that with heat recovery mineralizing 1 t-CO 2 using the AU process requires 3.6 GJ/t-CO 2 while that of the NETL needs 3.4 GJ/t-CO 2. Applying results of exergy analysis in the life cycle inventory (LCI) models of the AU and the NETL processes leads to 517 kg CO 2e and 683 kg CO 2e of greenhouse gas emissions (in CO 2 equivalents) respectively, for every ton of CO 2 mineralized in serpentinite.

    Original languageEnglish
    Pages (from-to)116-126
    Number of pages11
    JournalEnergy Conversion and Management
    Volume55
    DOIs
    Publication statusPublished - Mar 2012
    MoE publication typeA1 Journal article-refereed

    Keywords

    • CO mineralization
    • Exergy analysis
    • Life cycle assessment
    • Magnesium hydroxide
    • Magnesium silicate

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