Calcium oxide-based sorbents for CO2 capture at high temperature

Carbon capture and storage (CCS) has been recognized as a promising approach to mitigate the rapidly increasing amount of CO2 in the atmosphere. The key factor for the advancement of this technology lies in improved and cost-effective capture processes/materials. Pre-combustion CO2 capture from coal-fired power plants is of particular interest in integrated gasification combined cycle (IGCC) design. High concentrations of CO2 and elevated operating pressures/temperatures reduce the energy requirements of this process to 10-16%, which is roughly half that for post-combustion CO2 capture.[1] CaO has emerged as an attractive material to integrate in high temperature CO2 capture processes because of its favorable properties. However, the main drawback of CaO, namely sintering during calcination and thus dramatic decrease in surface area, has questioned its applicability on an industrial scale. To tackle the stability issue of CaO, different strategies have been examined from which incorporation of inert additives into CaO matrix shows great promise. High melting point refractory metal oxides have been identified as an example class of efficient additives. In this dissertation, two less common synthetic approaches, mechanochemistry and ultrasonic spray pyrolysis (USP), were utilized to prepare highly stable CaOcontaining sorbents for CO2 capture. The mechanochemical approach is as an example of top-down synthesis of materials, while spray pyrolysis is considered a bottom-up approach. First, a systematic study on the use of mechanochemistry (e.g., mechanical milling) for preparing CaO-based sorbents is reported. Important parameters such as milling intensity in high energy ball milling equipment, use of process control agent (i.e., wet or dry processing) and milling time were examined, and their effects on the performance and stability of treated CaO sorbents were studied. Next, the first use of ultrasonic spray pyrolysis as a continuous flow method for the facile synthesis of CaO-based materials is discussed. An extensive study of materials’ characterization and CO2 capture performance has been conducted to examine the efficacy of prepared sorbents. Moreover, importance of bottom-up synthetic approach in retaining CO2 capacity is discussed. This work concludes with modeling the sorbent’s performance via a classical shrinking core model to obtain quantitative values of useful parameters for equipment design (e.g., reaction rate constant and diffusivity decay). [1] Eide, L., I.; Bailey, D., W., Capture précombustion. Oil & Gas Science and Technology - Rev. IFP 2005, 60 (3), 475-484

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Sayyah, Maryam

Contributors dc:contributor

• Suslick, Kenneth S.
• Kenis, Paul J.A.
• Yang, Hong
• Flaherty, David W.

• Calcium Oxide
• CO2 capture
• Mechanochemistry
• Ultrasonic Spray Pyrolysis
• Ball Milling
• Electrostatic Precipitator
• Pre-Combustion
• Shrinking Core Model

Statement dc:rights

• Copyright 2013 Maryam Sayyah

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/46797

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/46797