Z. Helwani

Pressure Swing Adsorption Technologies for Carbon Dioxide Capture

The principles of pressure swing adsorption (PSA) for carbon dioxide capture are reviewed. Previous work on PSA, relevant modeling and experimental investigation for specifically carbon dioxide separation are also presented and significant findings highlighted. Simple rules for PSA process design based on analysis of the inherent properties of adsorbate-adsorbent systems encompassing equilibrium isotherm, adsorption kinetics, shape of breakthrough curves, screening and selection of adsorbent, bed porosity, adsorption time, purge to feed ratio, residence time, pressure equalization and rinse steps are provided to promote better understanding of the technology so that it gains wider acceptance in the future to address the global environmental concern, particularly in the removal of carbon dioxide as a greenhouse gas.

In-situ mineralization of carbon dioxide in a coal-fired power plant

ABSTRACT Mitigation of anthropogenic carbon dioxide is needed in order to allow societies to maintain the existing carbon-based infrastructure, while minimizing the effects of carbon dioxide (CO2) on the earth eco-system. A system that consists of pressure swing adsorption and in-situ mineralization unit was introduced to capture carbon dioxide (CO2) from a 700 MW pulverized coal-fired power plant. Results from the work demonstrate that pressure swing adsorption for post-combustion carbon capture consumed the least energy, followed by biomass co-firing, pre-combustion cryogenic-membrane hybrid, and post-combustion monoethanolamine absorption. For carbon capture and sequestration, the pressure swing adsorption-fixation system was found to yield the lowest environmental burden factor, followed by off-site sequestration in deep sea and depleted underground oil/gas fields.

Conversion of Saga Seeds into Adsorbent and Liquid Fuel from Pyrolysis and Solvent Extraction

Oil extract from Saga seeds offers potential uses as valuable chemical feedstock and liquid fuel. In this work, pyrolysis and solvent extraction were employed to extract liquid fuel from Saga seeds. The optimum yield of pyrolytic oil was obtained when pyrolysis temperature and nitrogen flow rate were 571°C and 271 cc/min, respectively. The heating value of oil from pyrolysis and solvent extraction was 11.42 and 37.76 MJ/kg, respectively. The solid char residues from pyrolysis were found to be able to adsorb Methylene Blue dye without being activated.

Carbon dioxide sequestration at elevated temperature by pressure swing adsorption

Modeling and simulation of CO2 capture from flue gases of coal fired power plant at high temperature are presented. The work employed a 19% potassium and 1% sodium hydrotalcite adsorbent, for which CO2 capacities in excess 0.84 mol/kg were measured at temperature of 575 K. Elution profiles from a pressure swing adsorption (PSA) unit also enabled analysis of adsorption and desorption process. A cyclic and multibed process for the continuous capture of CO2 was proposed. A mathematical model for the CO2−19% potassium and 1% sodium hydrotalcite adsorbent system, based on measured equilibria and kinetic data, was used for the assessment of the process in terms of CO2 product purity and recovery.