USDOE – Carbon Capture
Post-Combustion Carbon Capture
The Civil & Environmental Engineering research group along with the Mechanical Engineering research group at Prairie View A&M University performs research on the evaluation of post-combustion carbon capture methods using Polyethylenimine (PEI) functionalized titanate (TiO2) nanotubes.
Objectives
- Establish a knowledge base on the synthesis of TiO2 nanotubes, adsorption characteristics of PEI, and protocols available for the impregnation of PEI.
- Develop optimized protocols for synthesis of TiO2 nanotubes impregnated with PEI.
- Characterize the PEI impregnated TiO2 nanotubes and use it for refining the parameters for synthesis such as temperature, concentration and time.
Methodology (Proposed)
- Review literature to study the state of carbon capture technologies, nonmaterial synthesis protocols, reactor designs, and experimental protocols.
- Develop PEI impregnated TiO2 nanotubes.
- Evaluate thermal stability and morphological study of the PEI impregnated TiO2 nanotubes.
- Develop a fully functionalized CFD model that can be used for various reactor parameters and materials properties.
- Change the experimental testing of carbon capture under different conditions of temperature, concentrations, and time periods to determine optimal conditions for carbon capture.
- Identify a fully optimized and validated CFD model along with a standard operating procedure for bench scale carbon capture reactor
Findings, To Date (Based on Review of Literature)
- The current major CO2 capture technologies are oxy-combustion capture, pre-combustion capture, and post-combustion capture.
- Post-combustion carbon capture was found to be especially desirable due to its potential to retrofit existing power plants with reasonable cost.
- A simplified schematic of post-combustion carbon capture for a coal-fired power plant is shown in Figure 1. CO2 is captured after the flue gases are cleaned up by Electro Static Precipitator (ESP) and Flue Gas Desulfurization (FGD).
Figure 1: Schematic of post-combustion carbon capture in power plants.
- The current major post-combustion carbon capture technologies are absorption, adsorption, membrane, and cryogenics.
- Current technologies for post-combustion CO2 capture focus mainly on solvent-based absorption. However, the low pressure of the power plant flue gas would result in additional cost for CO2 compression, transportation and storage.
- Other disadvantages of absorption include degradation in an oxidizing atmosphere, higher energy intensity during regeneration, limited CO2 loading capacity, and corrosion with foaming and fouling characteristics.
- There are limited studies that used PEI impregnated TiO2 nanotubes in post-combustion carbon capture. The high surface areas and specific adsorption sites of porous materials make porous solid adsorbents good candidates for application in CO2 capture.
- Synthesizing highly efficient amines-functionalized nanoporous materials is still a big challenge; more efforts need to be put on the investigation of optimal parameters for synthesizing economic and effective nanomaterial for CO2 capture.
UTC-LSU TranSet LCA
Life-cycle Environmental Impact of High-Speed Rail System in the I-45 Corridor
The Houston-Dallas I-45 corridor was ranked as the top priority among 18 traffic corridors in Texas for the development of an Intercity Passenger Transit System, by the Texas A&M Transportation Institute. The city councils of Dallas and Houston have recently taken positive legislative steps towards the construction of a 240-mile high speed rail (HSR) system connecting the cities via Shinkansen N700 series trains with top speeds of 200 mph. At this juncture, there is an imperative to examine the potential life cycle environmental impacts of the HSR system and compare/contrast with the environmental impacts associated with existing transportation modes of highway and air travel. HSR systems powered by electricity have significantly lower releases of criteria air pollutants (CAP) and greenhouse gases (GHG) during operation stage, in comparison to conventional transportation by road/air. This project considers the total life cycle of an HSR system including all stages from ‘cradle-to-grave’ such as, raw material extraction, infrastructure development, vehicle manufacturing, electricity generation, operation & maintenance, and end-of-life for two components: Vehicle and Infrastructure. This project would conduct a holistic life cycle assessment (LCA) study exploring the energy and environmental impact of the HSR system and the role of this transportation mode in alleviating persistent air quality problems in the non-attainment areas of Houston and Dallas. This project would develop estimates for CAP, GHG emissions and energy consumption per vehicle/passenger-kilometer traveled under scenarios of varying passenger ridership/migration level to the HSR system. The outcomes from this LCA study would provide vital information to regulators, planners and researchers studying environmental impacts of fossil fuel usage in the transportation sector of the US; comparative analysis for passenger travel by HSR, highway and air modes will establish the inventory and methodological framework for conducting future LCA studies for potential HSR routes in multiple travel corridors of the South-Central US.