Cryogenic liquids for energy storage and carbon capture

Rama, Sidra (2020). Cryogenic liquids for energy storage and carbon capture. University of Birmingham. Ph.D.

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Abstract

Carbon capture is widely recognised as an essential strategy to meet global goals for climate protection. Although various CO2 capture technologies including absorption, adsorption and membrane exist, they are not yet mature for post-combustion power plants mainly due to the high energy penalty. Hence researchers are concentrating on developing non-aqueous solvents like ionic liquids, CO2-binding organic liquids, nanoparticle hybrid materials and microencapsulated sorbents to minimise the energy consumption for carbon capture.

This research aims to develop a novel and efficient approach by encapsulating sorbents to capture CO2 in a cold environment. The conventional emulsion technique is selected for the microcapsule formulation by using 2-amino-2-methyl-1-propanol (AMP), monoethanolamine (MEA) and triethanolamine (TEA) as the core sorbents and silicon dioxide (SiO2) as the shell. The microcapsule formulation parameters like core-shell ratio and emulsifiers are studied to formulate good microcapsules. Additionally, the microcapsules are characterised in terms of physio-chemical properties and structural properties. Furthermore, the sorption dynamics and effect of temperature on the CO2 loading capacity of the microcapsules using a self-developed pressure decay method and a continuous reactor are investigated. The results have shown that the following parameters formulated the best microcapsules: AMP core, 1 wt% Span85, 6:4 core-shell ratio, 400 rpm mechanical stirrer speed and 1200 rpm homogeniser speed. However, samples formulated with 0.5 wt% PGPR emulsifier (AMP core, 6:4 core-shell ratio, 400 rpm mechanical stirrer speed and no homogeniser) showed better surface properties with a larger surface area (92 m2/g) (SA) and pore size (43 Å) compared to the samples produced with the other two emulsifiers. Similarly, this sample showed both the best absorption capacity as well as absorption kinetics at both room temperature (0.0505 g/g) and low temperature with the highest absorption seen at -60 °C (0.0993 g/g). The encapsulation of CO2 sorbents showed promising result though further research is needed to replace the conventional sorbents.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):