Experimental and Numerical Investigation of La2NiO4 Membranes for Oxygen Separation: Geometry Optimization and Model Validation

Badr

et al. 2017

Self Cite

117

Summary The increased level of emissions of carbon dioxide into the atmosphere due to burning of fossil fuels represents one of the main barriers toward the reduction of greenhouse gases and the control of global warming. In the last decades, the use of renewable and clean sources of energies such as solar and wind energies has been increased extensively. However, due to the tremendously increasing world energy demand, fossil fuels would continue in use for decades which necessitates the integration of carbon capture technologies (CCTs) in power plants. These technologies include oxycombustion, pre‐combustion, and post‐combustion carbon capture. Oxycombustion technology is one of the most promising carbon capture technologies as it can be applied with slight modifications to existing power plants or to new power plants. In this technology, fuel is burned using an oxidizer mixture of pure oxygen plus recycled exhaust gases (consists mainly of CO2). The oxycombustion process results in highly CO2‐concentrated exhaust gases, which facilitates the capture process of CO2 after H2O condensation. The captured CO2 can be used for industrial applications or can be sequestrated. The current work reviews the current status of oxycombustion technology and its applications in existing conventional combustion systems (including gas turbines and boilers) and novel oxygen transport reactors (OTRs). The review starts with an introduction to the available CCTs with emphasis on their different applications and limitations of use, followed by a review on oxycombustion applications in different combustion systems utilizing gaseous, liquid, and coal fuels. The current status and technology readiness level of oxycombustion technology is discussed. The novel application of oxycombustion technology in OTRs is analyzed in some details. The analyses of OTRs include oxygen permeation technique, fabrication of oxygen transport membranes (OTMs), calculation of oxygen permeation flux, and coupling between oxygen separation and oxycombustion of fuel within the same unit called OTR. The oxycombustion process inside OTR is analyzed considering coal and gaseous fuels. The future trends of oxycombustion technology are itemized and discussed in details in the present study including: (i) ITMs for syngas production; (ii) combustion utilizing liquid fuels in OTRs; (iii) oxy‐combustion integrated power plants and (iv) third generation technologies for CO2 capture. Techno‐economic analysis of oxycombustion integrated systems is also discussed trying to assess the future prospects of this technology. Copyright © 2017 John Wiley & Sons, Ltd.

Section: Oxy‐fuel Combustion In Otrsmentioning

confidence: 99%

Oxy-fuel combustion technology: current status, applications, and trends

Nemitallah

Badr

et al. 2017

Self Cite

117

“…This optimization was performed by the investigation of Habib et al . . Therefore, in order to achieve the highest oxygen permeation rates for disc‐shaped BSCF membrane for the present (similar) geometry model, a gap width between the inner tube and the ITM is selected as 1 mm on both the air (feed) and the sweep (permeate) sides.…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…To obtain maximum oxygen permeation, the optimal value of the diameter of the sweep-side inner tube and the gap height (being the distance measured from the surface of the membrane) need to be determined. This optimization was performed by the investigation of Habib et al [33]. Therefore, in order to achieve the highest oxygen permeation rates for disc-shaped BSCF membrane for the present (similar) geometry model, a gap width between the inner tube and the ITM is selected as 1 mm on both the air (feed) and the sweep (permeate) sides.…”

Section: Conservation Of Speciesmentioning

confidence: 99%

Investigation of oxygen permeation through disc-shaped BSCF ion transport membrane under reactive conditions

Ahmed

Ben‐Mansour

et al. 2016

Summary The present work investigates the performance of Ba0.5Sr0.5Co0.8Fe0.2O3−δ ion transport membrane for separation of oxygen and its simultaneous reaction with gaseous fuels. A 2‐D axisymmetric model is considered to investigate the flow and combustion characteristics of methane in a button cell experimental model. A model that includes surface kinetics on the permeate and feed sides together with the bulk diffusion for BSCF membrane is developed and validated well against the experimental results. The effects of reaction on oxygen permeation and combustion characteristics are presented. Firstly, the nonreactive cases are investigated for oxygen permeation only. Later, the effects of increasing CH4% on the reactivity are explored. Finally, the effect of an increase in the operating temperatures on permeation of oxygen and reactivity are presented and quantified. It is found that the permeation of oxygen increases as the CH4% is increased in the sweep side because of an increase in the volume flow rates. The reactivity increased with an increase in the CH4%, however, beyond CH4 = 2% in the sweep side the amount of unburned CH4 also increased. It is also indicated that raising the operating temperatures results in shortened flame zones with more concentration in the vicinity of the ITM. Copyright © 2016 John Wiley & Sons, Ltd.

“…The CO/CO 2 concentration in conventional coal‐fired boiler is 95% higher than oxy‐fuel combustion with NO x emission reported to have reduced by a one‐third as a result of use of oxy‐fuel combustion . A comparison of oxy‐fuel, with nitrogen replaced by carbon dioxide, to air‐fuel combustion shows a reduced temperature levels and a slower fuel consumption in the oxy‐fuel combustion system . Pure oxygen required for oxy‐fuel combustion is produced by the cryogenic air separation technology which has been reported to be expensive and thermodynamically inefficient .…”

Section: Introductionmentioning

confidence: 99%

Investigation of performance of fire-tube boilers integrated with ion transport membrane for oxy-fuel combustion

Ben‐Mansour

Adebiyi

2016

Self Cite

Summary The performance of a carbon free fire‐tube boiler utilizing two‐pass oxygen transport reactors was numerically investigated. The influences of the oxygen transport reactors wall temperature on the reaction rate, oxygen permeation and heat flux were quantified. The performance of the reactors has been investigated at elevated temperature. It is observed that both heat transfer and combustion characteristics can be optimized at an elevated temperature of 1373 K. Increasing the mass fraction of methane in this reactor to 6% results in improvement of the heat transfer and combustion characteristics in the reactor. Further increase in CH4% did not lead to any significant improvement. The fuel flow rate variation did not have any significant impact on the reactor performance. It is indicated that the membrane temperature has significant effect on the reaction rates and oxygen flux in the upstream region in particular. Copyright © 2016 John Wiley & Sons, Ltd.