查看更多>>摘要：Heat release and mass transfer characteristics in micro power unit with dual-fuel at high environmental load are mainly investigated in this paper. Energy conversion equations are solved in both phases separated by a regressing gas-solid interface. The igniter jet is assumed as a cross flow and then added to the gas governing equations in the form of source terms. Analyses have focused on variations in temperature, heat release rate per volume and species concentration. Results show that the forced-convection heat transfer in the gas flame zone is performed under the effect of the cross flow. Meanwhile, the rapid depressurization process of the micro system results in an adiabatic expansion phenomenon of the combustion-gas near the solid surface. However, the sandwich propellant can always keep burning due to the continuous addition of energy source from the igniter combustion-gas of high temperature. The out-of-phase blowout effect, that is, the gas zones with strong heat release always keep away from the solid surface, also appears in the whole process. Significantly, when the initial pressure or the average flow velocity of igniter jet is lower than 20 MPa or 40 m/s, the temperature distribution in the flowfield is greatly affected by the initial state.
查看更多>>摘要：Gas separation properties of membranes are the significant parameters in CO2 capture process. It has been reported that membranes with high permeance and moderate CO2/N-2 selectivity are suitable for CO2 capture from coal-fired flue gas. However, with emerging high selectivity membrane and novel processes, it is essential to evaluate the influence of membrane selectivity on carbon capture performance, especially the significance of sub ambient membrane operation. In this work, a sub-ambient membrane-cryogenic hybrid process was designed for CO2 capture from coal fired and blast furnace flue gas. It was found that energy consumption of vacuum can be saved when membranes with high selectivity were operated at sub-ambient condition. The cost and energy consumption of the optimal cases for coal fired flue gas were 36.14 $/tCO(2) and 1.87 GJ/tCO(2) according to the economic evaluation. The parasite load decreased 7.11% over the base case of 168 MW. In addition, the capture cost and energy consumption of optimal case for blast furnace flue gas were 28.81 $/tCO(2) and 1.55 GJ/tCO(2), respectively. The parasite load decreased 15.55% over the base case of 17.81 MW. The designed hybrid processes presented competitive potential when applied in high CO2-content scenarios. In summary, the hybrid process based on membranes and cryogenic has been proven to have economic advantages under simulated conditions, indicating that it has the potential to be amplified by industrialization.
NSTL
Elsevier