Novel Amine Blends for Carbon (IV) Oxide Capture

The ever increasing amount of carbon (IV) oxide in the atmosphere is posing serious challenges to the environment. The consequent effect of this anomaly created by anthropogenic activities has resulted in different environmental degradation problems such as flooding, melting of polar ice, increase in mean global temperatures, deforestation, increase in ocean water levels etc. There is therefore an urgent need to reduce the emission of CO₂ into the environment so as to forestall the continuous occurrence of these environmental problems. A significant contributing factor to the continuous emission of CO₂ is the utilization of fossil fuels which (BP, 2017, 2018, 2019b, 2019a) state that its consumption and production will continuously increase into 2040. This can be attributed to the ever growing economies of different nations of the world requiring more energy to drive its activities. As such, it becomes imperative to sequester this harmful gas at source points to prevent its emission into the atmosphere.

A viable means to carry out such sequestration is Carbon Capture and Storage (CCS) technology. Different technologies such as adsorption, absorption, membranes, cryogenics (Li et al., 2011; Ghalia and Dahman, 2017) exist for CCS but amine scrubbing technology, an absorption technology has been revealed to be most mature, developed and deployed technology for carbon capture (Yu, Huang and Tan, 2015). Amine scrubbing technology shown in Fig. 1 uses amine solvents to strip CO₂ from counter current flowing flue gas stream exiting process systems in the absorber chamber, preventing their emission into the atmosphere.

Fig. 1. Amine Scrubbing Unit

There are primarily three classes of amine solvent; primary, secondary and tertiary amines. Each of these classes of amines faces setbacks in their deployment for carbon capture. For instance, primary amine such MEA exhibits high reaction kinetics but low CO₂ solubility, primary and secondary (DEA) amines exhibit high regeneration energy in the desorber chamber while tertiary amines (TEA) exhibit slow reaction kinetics despite their high CO₂ loading capacity. This contrariety exhibited by these pristine amines has therefore given birth to a new novel class of amine solvents known as Amine Blends. Amine blends consist of two or three pristine amine solvents whose properties such as CO₂ solubility, heat of regeneration and reaction kinetics complement to produce an energy efficient optimal solvent for carbon capture. This area of research is currently a hot topic in CCS as different researchers have extensively investigated process functionalities of novel amine blends such MDEA/PZ, MEA/AMP/PZ, MEA/MDEA, AMP/PZ, MPZ/PZ etc. so as to identify an optimal amine blend for energy efficient CO₂ scrubbing process.

Progress in being recorded in this regard as amine blends with improved process functionalities than their pristine amine solvents have been reported in literature (Nwaoha et al., 2016; Hamidi, Farsi and Eslamloueyan, 2018; Sobala and Kierzkowska-Pawlak, 2019). This is an evidence of a right step in the right direction but nonetheless, more intensive research in still needed as the world can no longer boast the luxury of time in the search for ways to solving the time-ticking bomb of climate change. Tri-solvents of amine blends have been reported in the literature but blends comprising four pristine amines have not been reported to the best knowledge of the author. This can be a new area of research as such blends may have most pristine amine solvents to optimize thereby further improving their overall process functionality. This is pertinent as the scientific community continuously investigates for novel compounds that can effectively and efficiently sequester CO₂ in process systems thereby preventing its emission into the atmosphere.

REFERENCES

BP (2017) BP Statistical Review of World Energy. 66th edn.

BP (2018) BP Statistical Review of World Energy. 67th edn.

BP (2019a) BP Energy Outlook 2040: February 2019. Available at: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjwxK_MhunjAhXFnFwKHa9nAaIQFjAAegQIABAC&url=https%3A%2F%2Fwww.bp.com%2Fcontent%2Fdam%2Fbp%2Fbusiness-sites%2Fen%2Fglobal%2Fcorporate%2Fxlsx%2Fenergy-economics%2Fenerg.

BP (2019b) BP Statistical Review of World Energy 2019. 68th edn. Available at: bp.com/statisticalreview.

Ghalia, M. A. and Dahman, Y. (2017) ‘Development and Evaluation of Zeolites and Metal – Organic Frameworks for Carbon Dioxide Separation and Capture’, (September 2016). doi: 10.1002/ente.201600359.

Hamidi, R., Farsi, M. and Eslamloueyan, R. (2018) ‘CO2 solubility in aqueous mixture of MEA, MDEA and DAMP: Absorption capacity, rate and regeneration’, Journal of Molecular Liquids. Elsevier B.V, 265, pp. 711–716. doi: 10.1016/j.molliq.2018.07.013.

Li, J. et al. (2011) ‘Carbon dioxide capture-related gas adsorption and separation in metal-organic frameworks’, Coordination Chemistry Reviews. Elsevier B.V., 255(15–16), pp. 1791–1823. doi: 10.1016/j.ccr.2011.02.012.

Nwaoha, C. et al. (2016) ‘Carbon dioxide (CO2) capture: Absorption-desorption capabilities of 2-amino-2-methyl-1-propanol (AMP), piperazine (PZ) and monoethanolamine (MEA) tri-solvent blends’, Journal of Natural Gas Science and Engineering. Elsevier B.V., 33, pp. 742–750. doi: 10.1016/j.jngse.2016.06.002.

Sobala, K. and Kierzkowska-Pawlak, H. (2019) ‘Heat of absorption of CO 2 in aqueous N,N-diethylethanolamine + N-methyl-1,3-propanediamine solutions at 313 K’, Chinese Journal of Chemical Engineering, 27(3), pp. 628–633. doi: 10.1016/j.cjche.2018.11.027.

Yu, C., Huang, C. and Tan, C. (2015) ‘A Review of CO 2 Capture by Absorption and Adsorption A Review of CO 2 Capture by Absorption and Adsorption’, (October 2012). doi: 10.4209/aaqr.2012.05.0132.