Nongray-Gas Effects in Modeling of Large-Scale Oxy–Fuel Combustion Processes

2012 ◽  
Vol 26 (6) ◽  
pp. 3349-3356 ◽  
Author(s):  
Chungen Yin
Keyword(s):  
Large Scale ◽  
Fuel Combustion ◽  
Combustion Processes

Optical Analysis of Pulse Combustion Using Shadowgraph and Planar CH-LIF Imaging Technique

2000 ◽  
Vol 123 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Yojiro Ishino ◽  
Tatsuya Hasegawa ◽  
Shigeki Yamaguchi ◽  
Norio Ohiwa
Keyword(s):  
Large Scale ◽  
Ccd Camera ◽  
Pulsation Period ◽  
Planar Imaging ◽  
Camera System ◽  
Band Emission ◽  
Pulse Combustor ◽  
Pulse Combustion ◽  
Combustion Processes ◽  
Ch Radical

Planar imaging of laser-induced fluorescence of CH radical is made to examine combustion processes in a valveless pulse combustor. An excimer-pumped dye laser tuned to a wavelength of 387 nm is used to excite the R1N″=6 line of (0,0) band of the B2Σ−−X2Π system of CH radical, and an image-intensified CCD camera system is used to detect the (0,1) band emission at around 435 nm. According to the CH-LIF images, it is found that the progress in combustion during a pulsation period is expressed by the enlargement and breakup of the earlobe-shaped flame front along the outline of a pair of large-scale eddies of fresh mixture.

scholarly journals Sulfur trioxide formation/emissions in coal-fired air- and oxy-fuel combustion processes: a review

2018 ◽  
Vol 8 (3) ◽  
pp. 402-428 ◽  
Author(s):  
Yerbol Sarbassov ◽  
Lunbo Duan ◽  
Vasilije Manovic ◽  
Edward J. Anthony
Keyword(s):  
Sulfur Trioxide ◽  
Fuel Combustion ◽  
Combustion Processes

Further Evaporation and Final Treatment of Process-Water Concentrates

1999 ◽  
Vol 40 (11-12) ◽  
pp. 25-32
Author(s):  
Paterson McKeough ◽  
Leena Fagernäs
Keyword(s):  
Large Scale ◽  
Treatment Process ◽  
Treatment Options ◽  
Paper Mill ◽  
Pilot Scale ◽  
Forced Circulation ◽  
Final Treatment ◽  
Solids Content ◽  
Combustion Processes ◽  
Future Work

The study is part of a longer-term effort aimed at developing a separate treatment process for evaporation-concentrates of paper-mill process waters. This article deals with research on the two key processing steps; namely, the further evaporation and the final treatment of the concentrates. In laboratory experiments, various feed waters, including several different TMP filtrates, were evaporated to high dry-solids contents. The condensates recovered in most experiments contained relatively small amounts of organic matter. The extent of vapourisation of organic acids, relative to water, increased somewhat with increase in dry-solids content. Two TMP concentrates from large-scale evaporation plants were further concentrated in a pilot-scale forced-circulation evaporator. Viscosity was the factor limiting the extent of concentration. Using an evaporation temperature of about 80°C, the maximum dry-solids contents achieved with the two different concentrates were about 45 wt% and about 60 wt%, respectively. Fouling of heat-transfer surfaces was observed with both concentrates. A techno-economic evaluation of final-treatment options for alkali-rich concentrates is under way. According to intermediate results, molten-phase combustion processes would not require support fuel once the dry-solids content of TMP concentrate exceeds about 50 wt%. The aim of future work is to optimise the overall treatment process.

scholarly journals Emission Behaviors of Inorganic Ultrafine Particles during Zhundong Coal Oxy-Fuel Combustion with Characterized Oxygen Input Fractions Comparable to Air Combustion

2018 ◽  
Vol 8 (9) ◽  
pp. 1486 ◽  
Author(s):  
Bin Fan ◽  
Chang Wen ◽  
Xianpeng Zeng ◽  
Jianqun Wu ◽  
Xin Yu
Keyword(s):  
Ultrafine Particles ◽  
Large Scale ◽  
Temperature Drop ◽  
Fuel Combustion ◽  
Low Rank ◽  
High Yield ◽  
Drop Tube ◽  
Aerodynamic Diameter ◽  
Ca 50 ◽  
Zhundong Coal

Zhundong low-rank coal is very likely to be utilized extensively in oxy-fired boilers in the near future. Its PM10 (particulate matter with an aerodynamic diameter of ≤10 μm) emission behaviors during oxy-fuel combustion need to be carefully studied before its large-scale use. The present study examines the emission behaviors of inorganic ultrafine particles (PM0.5, with an aerodynamic diameter of ≤0.5 μm), as well as PM10 during the combustion of Zhundong coal in air and oxy-fuel conditions (O2/CO2) at three characterized O2 input fractions, i.e., 21, 27 and 32 vol.%. The combustion experiments were carried out in a high-temperature drop-tube furnace (HDTF) at a combustion temperature of 1500 °C. The results show that PM0.5 is composed of Na, S, Mg and Ca, with total fractions of ~90%, while PM0.5–10 (with an aerodynamic diameter between 0.5 and 10 μm) predominantly contains Ca (~50–65%). At three characterized oxygen fractions during oxy-fuel combustion (OXY21, 27 and 32), the promoted O2 fraction was found to increase the yields of both PM0.5 and PM0.5–10. A higher particle-burning temperature and a lower CO2 fraction promote the reactions of both organically bound elements and inorganic minerals, increasing the partitioning of Mg and Ca and causing an increased yield of PM0.5. The yield of PM0.5 from air is high and similar to that from OXY32 while the yield of PM0.5–10 from air is similar to that from OXY27. The high yield of PM0.5 from air is mainly generated by the highest yields of Ca in four conditions.

Demineralization of Brazilian Coals for Use in Gasification and Oxy-Fuel Combustion Processes, Aiming to Reduce CO2 Emissions

2017 ◽  
Vol 31 (8) ◽  
pp. 8560-8571 ◽  
Author(s):  
Keila Guerra Pacheco Nunes ◽  
Kirstin Milbradt Engel ◽  
Eduardo Osório ◽  
Nilson Romeu Marcílio
Keyword(s):  
Co2 Emissions ◽  
Fuel Combustion ◽  
Combustion Processes

Subgrid combustion modelling for large-eddy simulations

2000 ◽  
Vol 1 (2) ◽  
pp. 209-227 ◽  
Author(s):  
S Menon
Keyword(s):  
Turbulent Flows ◽  
Internal Combustion Engines ◽  
Large Scale ◽  
Large Eddy Simulations ◽  
Accurate Prediction ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Small Scale ◽  
Large Eddy ◽  
Combustion Processes

Next-generation gas turbine and internal combustion engines are required to reduce pollutant emissions significantly and also to be fuel efficient. Accurate prediction of pollutant formation requires proper resolution of the spatio-temporal evolution of the unsteady mixing and combustion processes. Since conventional steady state methods are not able to deal with these features, methodology based on large-eddy simulations (LESs) is becoming a viable choice to study unsteady reacting flows. This paper describes a new LES methodology developed recently that has demonstrated a capability to simulate reacting turbulent flows accurately. A key feature of this new approach is the manner in which small-scale turbulent mixing and combustion processes are simulated. This feature allows proper characterization of the effects of both large-scale convection and small-scale mixing on the scalar processes, thereby providing a more accurate prediction of chemical reaction effects. LESs of high Reynolds number premixed flames in the flamelet regime and in the distributed reaction regime are used to describe the ability of the new subgrid combustion model.

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