CO2 Energy Reactor – Integrated Mineral Carbonation: Perspectives on Lab-Scale Investigation and Products Valorization

Abstract

To overcome the challenges of mineral CO2 sequestration, Innovation Concepts B.V. is developing a unique proprietary gravity pressure vessel (GPV) reactor technology and has focussed on generating reaction products of high economic value. The GPV provides intense process conditions through hydrostatic pressurization and heat exchange integration that harvests exothermic reaction energy, thereby reducing energy demand of conventional reactor designs, in addition to offering other benefits. In this paper, a perspective on the status of this technology and outlook for the future is provided. To date, laboratory-scale tests of the envisioned process have been performed in a tubular "rocking autoclave" reactor. The mineral of choice has been olivine [~Mg1.6Fe 2+ 0.4(SiO4) + ppm Ni/Cr], although asbestos, steel slags, and oil shale residues are also under investigation. The effect of several process parameters on reaction extent and product properties has been tested: CO2 pressure, temperature, residence time, additives (buffers, lixiviants, chelators, oxidizers), solids loading, and mixing rate. The products (carbonates, amorphous silica, and chromite) have been physically separated (based on size, density, and magnetic properties), characterized (for chemistry, mineralogy, and morphology), and tested in intended applications (as pozzolanic carbon-negative building material). Economically, it is found that product value is the main driver for mineral carbonation, rather than, or in addition to, the sequestered CO2. The approach of using a GPV and focusing on valuable reaction products could thus make CO2 mineralization a feasible and sustainable industrial process.

Regeneration of Sodium Hydroxide from a Biogas Upgrading Unit through the Synthesis of Precipitated Calcium Carbonate: An Experimental Influence Study of Reaction Parameters

“…This process is much less energy intensive than physical regeneration previously studied by various authors [35,37,38], making the process economically attractive. Many researches focused on the carbonation of residues for storing CO 2 , as for instance steel slags [39], air pollution control residues [32,33], argon oxygen decarburization slags [23], incineration bottom ash [40] or basic oxygen furnace slags [41]. Baciocchi et al [32,33] proposed an application of the process above explained using both NaOH and KOH as solvents, and Air Pollution Control residues as Ca + sources, focusing on the amount of CO 2 that could be definitely stored by this residues [32,42].…”

How Characterization of Particle Size Distribution Pre- and Post-Reaction Provides Mechanistic Insights into Mineral Carbonation

“…Thus, it can help elucidate effects of carbonation, such as the formation of precipitated layers or alteration of the microstructure, and of sonication (a technique to intensify the carbonation reaction), such as particle attrition and fragmentation. Of the three average particle diameters commonly obtained by laser diffraction (D50, D (4,3), and D(3,2)), the Sauter mean diameter (D(3,2)), being surface area sensitive, is the most important when it comes to the susceptibility towards mineral carbonation of powdery materials, since mineral carbonation reactivity is proportional to the exposed surface area. This mean diameter is also found to be the most sensitive to sonication effects, as it best detects the formation of micron-to sub-micron sized fragments.…”

“…Alkaline earth metals can be derived from natural minerals, waste residues, or even brines [1]. When performed in a reactor, mineral carbonation leads to the formation of a powder that can be composed of a carbonate alone (e.g., high-purity precipitated calcium carbonate) [2], or a mixture of one or more carbonates with other solid phases, such as silica and silicates [3]. Materials characterization thus plays an important role in assessing the potential to use these carbonates in commercial applications (e.g., filler in paper, aggregate in concrete) [4].…”

The technology of CO2 sequestration by mineral carbonation: current status and future prospects

“…The first and the most rate-limiting step is the CO 2 dissolution into solution from gas 2,49,50 , followed by the dissolution of Mg-or Ca-silicate minerals into solution. However, whether the former or the latter limits the extent of MC still remains in controversy 51,52 . But there is no doubt that both of them are the main difficulties.…”

“…The olivine they adopted has the nickel content of 0.27%. Furthermore, many researchers 6,14,52 believe that the Energy Reactor © invented by Innovation Concepts may be the most promising ex-situ direct MC method, as shown in of massive energy input which is limiting the economics of MC. In addition, due to high speed of slurry during the Energy Reactor © , particles will be attrited, which can remove the passivation layers of silica and facilitate the successive MC reaction.…”