Semester

Summer

Date of Graduation

2021

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Debangsu Bhattacharyya

Committee Member

Fernando V.Lima

Committee Member

Jianli Hu

Committee Member

David Mebane

Committee Member

Benjamin Omell

Abstract

Carbon capture, utilization, and storage (CCUS) is seen as a suite of technologies to curb the carbon dioxide emissions from the atmosphere and plays a crucial role to meet the net zero emissions target for many countries by 2050. One of the major sources for CO2 emissions is combustion of fossil fuels. Various innovative capture technologies are being explored because the state-of-the-art monoethanolamine (MEA) based carbon capture technology has drawbacks such as corrosion, energy penalty. There are several potential solvents that have lower energy penalty, but they are highly viscous or may turn into solid phase in the absorber or desorber thus making it difficult to use them in conventional towers. Micro-Encapsulated Carbon Sorbents (MECS) is a new, promising technology for the capture of carbon dioxide that could overcome some of the challenges associated with the highly viscous or phase change materials. Microencapsulation is a microfluidic process where a substance is encapsulated within an inert polymer material. Microcapsules containing the solvent can be produced with diameters ranging from 100-600 microns. The small size of these microcapsules results in a high specific surface area per unit volume, which can enhance mass and heat transfer rates by orders of magnitude.

The aim of this research is to develop multiscale process models for MECS technology to better our understanding of the operational and economical challenges at a commercial scale. First, a rigorous capsule model with sodium carbonate as encapsulated solvent has been developed and validated with the experimental data. The reactor level model integrates the bulk scale mass, heat transfer, and hydrodynamics with capsule model that encompasses solvent physio-chemical properties, kinetics, mass and heat transfer. The resulting multi-scale model is then used to simulate both absorption and regeneration stages for a temperature swing system. The performance of MECS technology in a fixed bed and moving bed reactor configurations is evaluated. As the solvent resides inside the microcapsule it is difficult to measure, hence the study proposes a soft sensing approach to estimate the water content in the capsule. The developed soft sensor is used in the control framework put together for maintaining the water content and key process variables at their desired levels. The scope of the work also includes the techno-economic analysis of CO2 absorption for a 644 MWe gross power plant to understand the commercial feasibility of this technology. Further, the sensitivity with respect to encapsulated solvent is also shown by comparing solvents namely sodium carbonate, ionic liquids, and piperazine (PZ).

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