Ignition Characteristics for Methane‐Air Mixtures atVarious Initial Temperatures

Zhang, Qi; Li, Wei

doi:10.1002/prs.11561

Cited by 28 publications

(12 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…and is combusted in the presence of a 5% stoichiometric excess of air (2.725 m 3 ) will be diluted pre-ignition to 6.7% CH 4 . This is comparable to the volume fraction of methane employed for methane-air ignition (6.5 and 10.5% v/v; Zhang and Li, 2013) and is within the flammability limits for methane ignition (5 to 15% v/v). Whilst this example evidences that use of low CH 4 composition for ignition is achievable, commercial micro-turbines and larger scale CHP engines are ordinarily specified to operate at minimum CH 4 compositions of 30%…”

Section: Downstream Gas Phase Management For Recovery and Re-usesupporting

confidence: 61%

Dissolved gas separation for engineered anaerobic wastewater systems

Heile

Chernicharo

Brandt

et al. 2017

Separation and Purification Technology

View full text Add to dashboard Cite

Dissolved gases produced within engineered anaerobic processes subsequently create a fugitive emission which can have financial, environmental and health and safety implications. Whilst desorption technology has been used to control dissolved gases in the drinking water sector, there is considerably less understanding of its deployment in wastewater for which there are numerous existing and emerging challenges. This review therefore focuses on existing and proposed technological approaches to gas desorption in engineered anaerobic wastewater processes, with specific emphasis on technology compatibility and downstream gas phase management. Simplified engineered solutions such as diffused aeration and multi-tray aerators appear robust solutions for implementation into wastewater. However, these processes are characterised by a low mass transfer coefficient and require high gas to liquid ratios (G/L) to achieve reasonable separation, which suggests their suitability is limited to small scale applications, in which gas recovery is not a priority. Packed columns and membrane contactors afford process intensification through increasing interfacial area which favours large scale applications; although both will require prefiltration technology to obviate media clogging. Vacuum or steam is the preferred driving force for separation when gas recovery is sought, while sweep-gas is energetically favoured. Sweep-gas has been used for gas recovery by operating at G/L toward the equilibrium value, which somewhat constrains mass transfer. Process selection must therefore be weighted on whole life cost, but will also be dependent upon process scale, financial (e.g. incentivisation) and non-financial (e.g. carbon) instruments, which are strongly influenced by regional policy.

show abstract

Section: Downstream Gas Phase Management For Recovery and Re-usesupporting

confidence: 61%

Dissolved gas separation for engineered anaerobic wastewater systems

Heile

Chernicharo

Brandt

et al. 2017

Separation and Purification Technology

View full text Add to dashboard Cite

show abstract

“…Based on previous studies [35][36][37][38][39][40][41][42][43][44], we synchronized the trends in the peak explosion pressures and the peak explosion temperatures of the pure gaseous fuel/air mixtures. However, Figure 3 shows that the concentration that produced the maximum peak pressure of the IPN/air aerosols with a mean SMD of~34 mm was greater than the concentration that produced the maximum peak temperature.…”

Section: Explosion Pressures and Flame Temperaturesmentioning

confidence: 99%

A Comparative Study of the Explosion Characteristics of IPN and IPN/JP‐10 Mixtures in Air Aerosols

Wang

2017

Propellants Explo Pyrotec

View full text Add to dashboard Cite

This article presents a comparison of the explosion characteristics of mixtures of isopropyl nitrate (IPN, (CH 3 ) 2 CHONO 2 ) and JP-10 (C 10 H 16 , tricycle [5.2.1.0 2,6 ] decane) in air aerosols. The explosion pressure, flame temperature, maximum rate of pressure rise, maximum rate of temperature rise, and lower flammability limits (LFLs) were measured for two sets of IPN and mixed IPN/JP-10 in air aerosols at different concentrations and Sauter mean diameters (SMDs) of 19 mm and 34 mm, respectively, and the values were compared with the experimental results of JP-10/air aerosols with SMDs of 20 mm and 35 mm (from our previous research). Experiments were also performed to study various concentrations at various ignition energies for the IPN/ air aerosols and the explosions of binary mixture aerosols with various mass ratios of IPN and JP-10. The experimental results indicated that for the IPN/air and JP-10/air aerosols with a mean SMD of~34 mm, the maximum peak pressure and maximum peak temperature of the IPN/air aerosols were greater than those of the JP-10/air aerosols. The maximum rate of pressure rise of the IPN/air aerosols reached a maximum value of 395.3 MPa/s at a mean SMD of~34 mm, and the pressure increased more abruptly in the IPN/air aerosols than in the JP-10/air aerosols. The LFLs of the IPN/air aerosols occurred with a total concentration of 197 g/m 3 at a mean SMD of 19 mm and a total concentration of 233 g/ m 3 at a mean SMD of 34 mm, whereas the LFLs for the JP-10/air aerosols with SMDs of 20 mm and 35 mm were less than 47 g/m 3 and 40 g/m 3 , respectively. The experimental results presented here also showed that the maximum peak pressure was 1.07 MPa at a binary liquid mass ratio of IPN:JP-10 (%) of 72 : 28 and a mean SMD of~34 mm.Keywords: IPN/air and JP-10/air aerosols · Explosion characteristics · Lower flammability limit · Ignition energy · Various mass ratios of binary mixtures 2 3 4 5 6 7 8

show abstract

“…Among the gaseous explosion disasters, the overpressure associated with methane/air explosions is a major hazard in underground coal mines . To effectively prevent loss from methane/air explosions in mines, knowledge of the related explosion process and its action are required.…”

Section: Introductionmentioning

confidence: 99%

Explosion and flame characteristics of methane/air mixtures in a large‐scale vessel

Zhang

Chen

Xiu

et al. 2014

Process Safety Progress

View full text Add to dashboard Cite

In this study, experiments of explosions and flame characteristics in methane/air mixtures are performed in a 10-m 3 vessel. Pressure gauges and a high-speed camera are utilized to record the pressure trajectories and the flame propagation process of ignition growth. The experimental results show that the maximum value of overpressure and the maximum rate of the explosion pressure rise are 0.596 MPa and 1.82 MPa/s for the methane (9.5% in volume)/air mixture at atmospheric conditions, respectively. Both values are higher than for other mixtures with different compositions. The results also indicate that the overpressure from the large-scale vessel in this study is lower than that of a smaller apparatus (e.g., 5-L closed cylindrical vessel). This difference occurs due to the cooling effect and because the reflected sonic disturbances by the vessel wall affect the explosion process and weaken the energy during the pressure attenuation stage, thus rendering the value of overpressure in the large-scale apparatus lower than in the tiny cylindrical vessels. The maximum overpressure is observed at 0.75 m for C 5 7% ("C" means the methane concentration) and 9.5% but at 1.3 m for C 5 5%, 6.5%, 11.2%, and 13%. These results indicate that methane/air is an easier means to generate overpressure and that the overpressure is higher near the stoichiometric condition. Based on the analysis of the flame propagation process, the mean value of the flame speed of methane (C 5 9.5%)/air is calculated to be approximately 2.43 m/s because the nonuniformity of the chemical reaction at the flame front results in a maximum fluctuation of flame speed of approximately 28.5%. The flame thickness (u) of methane (C 5 9.5%)/air fluctuates between 9.84 and 10.95 mm, with a mean value of 10.53 mm.

show abstract

Ignition Characteristics for Methane‐Air Mixtures atVarious Initial Temperatures

Cited by 28 publications

References 11 publications

Dissolved gas separation for engineered anaerobic wastewater systems

Dissolved gas separation for engineered anaerobic wastewater systems

A Comparative Study of the Explosion Characteristics of IPN and IPN/JP‐10 Mixtures in Air Aerosols

Explosion and flame characteristics of methane/air mixtures in a large‐scale vessel

Contact Info

Product

Resources

About