Thursday, 12 September, 2013
Speaker: Dr. Arvind Rajendran, University of Alberta
Title: "Adsorption Based CO2 Capture"
Post-combustion power plants are the major sources of CO2 emissions. Given that fossil fuels will be the major sources of energy in the next few years, capture of CO2 from these sources for sequestration could be a possible short term solution for abating greenhouse gas emissions. Pressure/Vacuum swing adsorption (P/VSA) processes using solid sorbents are considered as viable options.
Adsorption processes are cyclic in nature and consist of a sequence of discrete steps. The specific sequence in which these steps are combined plays a significant role in the performance of the process. Owing to the specific nature of the separation problem, e.g., feed composition, pressure, type of adsorbent etc., it is often not straightforward to choose a specific sequence that satisfies constraints such as purity, recovery that the process needs to satisfy.
In this presentation, we report the systematic procedure for the synthesis of a P/VSA processes for CO2/N2 separation using zeolite 13X as adsorbent. Single component and binary isotherms of N2 and CO2 measured in our laboratories have been incorporated into a rigorous non-isothermal non-isobaric process simulation model. Using the model we have designed variety of P/VSA cycles for post-combustion CO2 capture.
The optimization of P/VSA possesses is computationally challenging as the governing equations are coupled non-linear partial differential equations (PDEs) with solutions having sharp fronts moving along the adsorption column. Using high-resolution finite volume schemes to solve the model equations, we have been able to perform multi-objective optimization without any model reduction. The optimization allows us to understand the trade-off between CO2 purity and recovery for a particular process. In addition, for configurations where high purity (>90%) and high recovery (>90%) are achieved, a second phase optimization has been performed to maximize CO2 productivity and minimize energy consumption with purity and recovery being constraints.
Based on the optimization algorithm, we have demonstrated the adsorptive CO2 capture process on a pilot plant that uses ≈40 kg of adsorbent. We will discuss the results of the pilot plant experiments where were have been able to achieve the purity and recovery targets set by the US Department of Energy, using a single-stage process. These results along with data concerning energy consumption will be discussed. Finally, the potential of the optimization approach is further illustrated by discussing how this approach can be used for screening potential CO2 sorbents.
Seminar not web cast
Web site http://www.cme.engineering.ualberta.ca/en/FacultyStaff/FacultyAcademicStaff/Rajendran.aspx
Visit https://www.chem.utk.edu/seminars-programs/departmental-seminar to view the 2013 Fall Chemistry seminar schedule & directions to view live & archived web casts