Heat optimisation of a staged gas-solid mineral carbonation process for long-term CO2 storage

Ron Zevenhoven*, Sebastian Teir, Sanni Eloneva

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedingConference contributionScientificpeer-review

2 Citations (Scopus)

Abstract

The carbonation of silicate minerals, primarily magnesium silicates, offers an interesting CO2 emissions mitigation option for Finland. Despite large resources of serpentine-type mineral in Finland and at many other places worldwide (exceeding the amount needed to bind the earth's fossil carbon resources) the chemical processing leaves much to be improved. Important features are the very slow chemical kinetics of magnesium silicate carbonation and the fact that the overall carbonation reaction is exothermic. Currently, two carbonation routes can be distinguished: Wet processes using aqueous solutions that give reasonable chemical kinetics while suffering from bad energy economy, and dry, gas-solid processes for which less good chemical kinetics have been achieved so far, but with better energy economy characteristics. The energy economy of a two- or three-stage gas-solid process for magnesium silicate is addressed in this paper. This involves extraction of reactive magnesium as magnesium oxide or hydroxide in an atmospheric pressure step, followed by carbonation at a higher temperature (>500°C) and at elevated pressures (>20 bar) that allow for reasonable carbonation reaction kinetics under conditions where magnesium carbonate is thermodynamically stable. Two goals must be achieved at the same time in a process that is feasible for large-scale application: The kinetics in the individual reactors must be fast enough, and the heat produced in the carbonation step must be sufficient to compensate for energy inputs to the preceding step(s). Excess heat will be of such a temperature level that it may be used in a steam cycle to produce electricity. The results of the paper show what temperature combinations will allow for operation at a negative or zero energy input, for a given pressure of the carbonation process step, given a degree of carbonation conversion and given other energy inputs, such as for mineral preparation and CO2 pre-heat. Softwares used were HSC and Aspen Plus. Also, a few results from gas-solid kinetics studies with magnesium oxidebased materials at the elevated pressures considered are included.

Original languageEnglish
Title of host publicationECOS 2006 - Proceedings of the 19th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems
EditorsChristos A. Frangopoulos, Constantine D. Rakopoulos, George Tsatsaronis
PublisherNational Technical University of Athens
Pages1661-1669
Number of pages9
ISBN (Electronic)9608758424
Publication statusPublished - 2006
MoE publication typeA4 Article in a conference publication
Event19th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2006 - Aghia Pelagia, Crete, Greece
Duration: 12 Jul 200614 Jul 2006

Publication series

NameECOS 2006 - Proceedings of the 19th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems

Conference

Conference19th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2006
Country/TerritoryGreece
CityAghia Pelagia, Crete
Period12/07/0614/07/06

Keywords

  • CO storage
  • Heat optimisation
  • Mineral carbonation

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