CO2CRC/HRL Mulgrave Capture Project: (Pre-Combustion)after Trials Campaign 1. September 2009
| Area of research | Results |
| Solvent Absorption Rig | |
Material Trialled
Operating Conditions
|
Operational Difficulties
Comparative Performance
|
| Membrane Gas –Solvent Absorption | Results |
Membrane contactor – removal of CO2 from syngas by solvent absorption into 30wt% potassium carbonate solution, where the membrane controls the mass transfer area and flow regime of both gas and solvent. Trial of a commercial polypropylene hollow-fibre module. |
CO2 removal from syngas was achieved, and under the best performance conditions for one module the CO2 vol percentage in the syngas was almost halved. Co-or counter-current flow had little influence on the performance of the system, perhaps due to the small size of the module. The mass transfer coefficient for CO2 absorption was found to be a function of the liquid to gas flow rate, due to the effect on boundary layer thickness. However, the calculated mass transfer coefficient was less than similar studies reported under laboratory conditions. |
| Gas Separation Membranes | Results |
A range of polymeric membranes were trialled as part of the first campaign. Two rubbery polymeric membranes were trialled that are CO2 selective over H2 (flat sheet arrangement), along with two commercial hollow fibre units, that are CO2 selective over N2. Also, a carbon nanoporous membrane was trialled at temperature. |
All membranes demonstrated CO2 separation from N2, with the rubbery polymeric membranes showing CO2 separation from H2 with limitations. One rubbery polymeric membrane proved susceptible to water present and rapidly degraded, the other showed evidence of build-up of water within the polymeric structure but without significant degradation. The commercial hollow fibre membrane units demonstrated poor separation of CO2 from H2, with the composition ratio in the permeate stream similar to that in the feed. Indicating that only N2 removal had occurred and that a further process stage would be required. |
| Adsorbents | Results |
| A versatile adsorption apparatus was designed and constructed to enable us to carry out breakthrough and cyclic adsorption experiments at high temperature for the materials developed. The apparatus can be used for rapid screening of adsorbents to judge their feasibility at high temperatures and high pressures. | Adsorbent columns with the various solid adsorbents were prepared and their breakthrough adsorption experiments were performed to evaluate the capacity of carbon dioxide capture in different conditions. Adsorption capacity decreased with increase in temperature for zeolite 13X and calcium chabazite. Zeolite 13X showed better performance at temperatures lower than 200°C, calcium chabazite appeared to have better adsorption capacity at higher temperature. Although hydrotalcite materials showed lower adsorption capacity than other adsorbents, the adsorption capacity was increased at higher temperature. It is expected that the optimisation of the adsorption process at high temperature and pressure conditions can be achieved with the controlled pelletising method of adsorbents and the evaluation of the effect of contaminants. |
| Economics | Results |
Economic framework was developed to do costing for large scale capture as well as integrated plants |
Work is continuing |
| Heat and Process Integration | Results |
| Heat and Process Integration study is ongoing using pinch analysis method. | Initial study results look promising. Running CO2 capture at hotter temperatures reduces the amount of energy loss by reducing the amount of water removed from the gas |
