Super-adiabatic flame temperatures in premixed methane flames: A comparison between oxy-fuel and conventional air combustion

Stelzner, Björn; Weis, C.; Habisreuther, Peter; Zarzalis, Nikolaos; Trimis, D.

doi:10.1016/j.fuel.2017.01.025

Cited by 27 publications

(16 citation statements)

References 12 publications

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“…The latter is captured, while the hydrogen-rich syngas feeds a combined cycle plant for power generation. The oxy-fuel approach utilizes pure or nearly pure oxygen for combustion, such that primarily CO 2 and H 2 O are produced by the process [5,8]. All these approaches are characterized by very high energy penalties: the plant net efficiency could be reduced of about 8-12 percentage points in case of post-combustion processes (mainly due to solvent regeneration) [9,10], and of 7-10 percentage points in case of pre-combustion approach [10].…”

Section: Introductionmentioning

confidence: 99%

CO2-free coal-fired power generation by partial oxy-fuel and post-combustion CO2 capture: Techno-economic analysis

Cau

Tola

Ferrara³

et al. 2018

Fuel

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Among the carbon capture and storage (CCS) technologies suitable for power generation plants, partial oxy-combustion coupled with post combustion CO 2 capture is gaining interest, since such a hybrid configuration could allow to reduce the size and enhance the performance of postcombustion CO 2 capture by operating combustion with air enriched with oxygen and reducing the dilution of flue gas. Moreover, partial oxy-combustion is a potential candidate for the retrofit of existing steam plants because it could be based on an almost conventional boiler and requires a smaller CO 2 capture section. This work presents the results of a comparative techno-economic analysis of a 1000 MW th partial oxy-combustion plant based on an ultra-supercritical pulverized coal combustion power plant integrated with a post-combustion CO 2 capture system and geological storage in saline aquifer. In particular, plant performance is assessed by using simulation models implemented through Aspen Plus 7.3 and Gate Cycle 5.40 commercial tools, whereas economic performance are evaluated on the basis of the expected annual cash flow. The analysis shows that, for new plants, this hybrid approach is not feasible from the economic point of view and full oxy-combustion potentially remains the most profitable technology even if, in the short-term period, the lack of commercial experience will continue to involve a high financial risk.

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Section: Introductionmentioning

confidence: 99%

CO2-free coal-fired power generation by partial oxy-fuel and post-combustion CO2 capture: Techno-economic analysis

Cau

Tola

Ferrara³

et al. 2018

Fuel

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“…However, in the oxygen-enriched condition, especially in fuelrich conditions, the maximum temperature can locally exceed the adiabatic flame temperature near the flame front. This phenomenon is called super-adiabatic flame temperatures (SAFT) caused by the overshoot in the H 2 O production, 60 which can also be observed in oxy-hydrocarbon flames. 61 In lean conditions, the SAFT happens when Ω > 0.75, while in rich conditions, it occurs even for NH 3 /air flame and increasingly notable with Ω.…”

Section: Resultsmentioning

confidence: 99%

Numerical Study on the Premixed Oxygen-Enriched Ammonia Combustion

Wang

et al. 2020

Energy Fuels

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In recent years, ammonia attracts much attention from researchers as a carbon-free energy carrier, but low reactivity hinders the direct use of ammonia in combustion applications. In this study, several essential combustion properties were numerically studied to explore the possibility of using oxygen enrichment to enhance ammonia combustion. Fuel lean and rich oxygen-enriched ammonia flame was simulated by planar flame and one-dimensional spherical flame under various oxygen fractions. Results show that increasing oxygen content substantially increases the laminar burning velocity and mixture heating value but decreases the burned gas Markstein length and combustion efficiency. NO is the major NOx emission, which rises with oxygen content for rich combustion but nonmonotonically changes for lean combustion due to the start-up of NO post-reduction at high temperature. The chemical effect of N2 possesses negligible influences on most of the flame properties, except for weakening the NO post-reduction in the burned gas. Competition between the increase in flame temperature and the decrease in N2 content leads to the maximum chemical effect of N2 occurring at the oxygen fraction of 0.6. In summary, oxygen enrichment can be an effective option to solve the problems impeding ammonia fuelization.

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“…The calculations were performed for the following cold and hot conditions: ambient air conditions to simulate the experimental calibration procedure; air was taken to be dry and free of trace gases (mole fractions , ); flame conditions were simulated without the flame gas flowing around the dilution tube, just by defining the temperature to be 1000 K at the orifice (Zhao, Yang, Wang, et al., 2003) and using the tube wall temperature profile shown in figure 1, assuming a CH 4 /O 2 oxy-fuel flame, equivalence ratio Φ = 2.4, C / O = 0.6, the flame gas concentrations were estimated from Köhler et al. (2016) and from Stelzner, Weis, Habisreuther, Zarzalis, & Trimis (2017). They are listed in table 1.…”

Section: Methodsmentioning

confidence: 99%

A computational fluid dynamics study of flame gas sampling in horizontal dilution tubes

Mätzing,

Vlavakis,

Trimis

et al. 2022

Flow

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The performance of horizontal dilution tubes is investigated by Reynolds-averaged Navier–Stokes and large-eddy simulations. The flame gas enters the dilution tube through a pinhole. The orifice flow and the dilution process inside the tube are studied. The volume flow through the orifice is shown to be proportional to the square root of the pressure drop. The discharge coefficient is 0.9 ± 0.3 in the cold air (calibration) case and drops to 0.35 under hot (flame) conditions. The resulting dilution ratio is roughly a factor of five below typical literature data. The gas sample remains in the wall boundary layer and the mixing process is not complete at the end of the dilution tube. Turbulence decays rapidly behind the tube inlet, which shifts the flow into the laminar to turbulent transition regime. Turbulence increases significantly in the outlet section which has much smaller pipe cross-sections. Despite its relatively low Reynolds number, the outlet flow to the particle sizer (or to the gas analyzer) is clearly turbulent, and interactions with the wall are probable. The results are in agreement with previous findings from laminar jets in cross-flow. Guidelines for optimization of the sampling conditions are suggested.

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Super-adiabatic flame temperatures in premixed methane flames: A comparison between oxy-fuel and conventional air combustion

Cited by 27 publications

References 12 publications

CO2-free coal-fired power generation by partial oxy-fuel and post-combustion CO2 capture: Techno-economic analysis

CO2-free coal-fired power generation by partial oxy-fuel and post-combustion CO2 capture: Techno-economic analysis

Numerical Study on the Premixed Oxygen-Enriched Ammonia Combustion

A computational fluid dynamics study of flame gas sampling in horizontal dilution tubes

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