Renato Cabral – Improvement of oxy-combustion using thermodynamic and exergetic analysis
Carbon capture and storage (CCS) is generally recognised as providing an essential role to reduce anthropogenic carbon dioxide (CO2) emissions from burning fossil fuels for electricity generation. Oxy-combustion is a promising CCS technology based on the idea of burning a fuel with high purity oxygen (O2) instead of air, thus increasing the concentration of CO2 in the flue gas. However, flue gas must still be further purified and compressed because CO2 concentrations are still below the design specifications of the pipeline.
Producing O2 and purifying CO2 introduces the need for including an air separation unit (ASU) and a gas processing unit (GPU), which are energy intensive and reduce the net efficiency of oxy-combustion. Because of this, it is important to decrease this parasitic energy consumption if oxy-combustion is to be deployed for CCS. Improving the efficiency of the process by reducing the energy consumption can increase the capital costs of the oxy-combustion, which would produce electricity at higher cost. As such, this work aims at identifying the potential for improving oxy-combustion using a rational approach grounded on the laws of thermodynamics and techno-economic analysis.
Jiajun Cen – A quantitative analysis of convective mixing dynamics in porous media
Carbon Capture and Storage in deep saline aquifers has been considered as a high potential climate change mitigation measure at the interim time-scale. Carbon dioxide (CO2) from point sources are captured, compressed from the gas phase into liquid and injected in geological formations. Saline aquifers are widely available, thus can be found near a CO2 point source, and they are often located at accessible depths (~800m to 3km). More importantly, it contains a large body of water with dissolved salts (called brine) wherein CO2 can dissolve and be trapped. To better comprehend the mixing dynamics of the CO2 and brine, and to explorer the key parameters controlling the convective transport of CO2 in the porous medium, researchers perform experiments with analogue fluids. These experiments provide invaluable insights, but are costly and time consuming. In this talk, we present a simple to implement and cost-effective finite element method model to simulate mixing of analogue fluids which can be readily extended to simulated convective mixing of CO2 and brine inside 3D images of real rocks. This model is used to quantify and compare the mixing dynamics of 2D and 3D simulations which we will detail during this presentation.
About the Series
The Grantham Changing Planet seminar series is run by students and staff on the Science and Solutions for a Changing Planet (SSCP) Doctoral Training Program. The aim is to complement the diversity of environmental research here at Imperial College London and promote links to the broader community in UK and beyond. It offers the chance to hear the latest in understanding, adapting to and mitigating environmental problems.