The Effect of the Residence Time in the High Temperature Field on the Fullerene and PAH Formation Mechanism

2011 ◽  
Author(s):  
Tatsuya Saika ◽  
Youhei Sakita ◽  
Masahiko Shibahara
Keyword(s):  
High Temperature ◽  
Residence Time ◽  
Formation Mechanism ◽  
Flue Gas ◽  
Combustion Process ◽  
Hydrocarbon Fuel ◽  
Experimental Conditions ◽  
Reduced Pressure ◽  
Reaction Field ◽  
High Temperature Reaction

Fullerenes were generated and observed in the combustion processes of hydrocarbon fuel under reduced pressure conditions however the fullerene formation mechanism from PAHs in fuel rich hydrocarbon flames under reduced pressure conditions has not been clarified yet. In the present study, the effects of the residence time in the high temperature reaction field were investigated experimentally and the effects of the residence time on the contents of fullerenes and PAHs were discussed. The experimental results showed that the contents of fullerenes as well as PAHs in the total soot collected from the flue gas decreased with the increase of the residence time in the range from 800 to 1500 degree Celsius. On the other hand, the contents of fullerenes in the total soot decreased with the increase of the residence time over 1500 degree Celsius because the total PAHs contents in the flue gas increased under the present experimental conditions. It is essential for the fullerene generation to realize the optimal residence time from 800 to 1500 degree Celsius as well as that over 1500 degree Celsius with an appropriate PAH partial pressure in the combustion process.

Study of high-pressure air jet controlled compression ignition with compound thermodynamic cycle for combustion and emission formation process

2020 ◽  
pp. 146808742096933
Author(s):  
Xiangyu Meng ◽  
Sicheng Liu ◽  
Jingchen Cui ◽  
Jiangping Tian ◽  
Wuqiang Long ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Low Temperature ◽  
Formation Process ◽  
Combustion Process ◽  
Thermodynamic Cycle ◽  
Compression Ignition ◽  
Temperature Reaction ◽  
Air Jet ◽  
High Temperature Reaction

A novel method called high-pressure air (HPA) jet controlled compression ignition (JCCI) based on the compound thermodynamic cycle was investigated in this work. The combustion process of premixed mixture can be controlled flexibly by the high-pressure air jet compression, and it characterizes the intensified low-temperature reaction and two-stage high-temperature reaction. The three-dimensional (3D) computational fluid dynamics (CFD) numerical simulation was employed to study the emission formation process and mechanism, and the effects of high-pressure air jet temperature and duration on emissions were also investigated. The simulation results showed that the NOx formation is mainly affected by the first-stage high-temperature reaction due to the higher reaction temperature. Overall, this combustion mode can obtain ultra-low NOx emission. The second-stage high-temperature reaction plays an important role in the CO and THC formation caused by the mixing effect of the high-pressure air and original in-cylinder mixture. The increasing air jet temperature leads to a larger high-temperature in-cylinder region and more fuel in the first-stage reaction, and therefore resulting in higher NOx emission. However, the increasing air jet temperature can significantly reduce the CO and THC emissions. For the air jet duration comparisons, both too short and too long air jet durations could induce higher NOx emission. A higher air jet duration would result in higher CO emission due to the more high-pressure air jet with relatively low temperature.

The Combustion Characteristics of n-Heptane Fueled HCCI Engine Operation With Gaseous Fuels Admission

2006 ◽  
Author(s):  
C. Liu ◽  
G. A. Karim ◽  
A. Sohrabi ◽  
F. Xiao
Keyword(s):  
Carbon Monoxide ◽  
High Temperature ◽  
Combustion Process ◽  
Cylinder Pressure ◽  
Engine Operation ◽  
Hcci Engine ◽  
Gaseous Fuels ◽  
High Temperature Reaction ◽  
Temperature Combustion ◽  
Combustion Region

The effects of the introduction of the gaseous fuels, methane, hydrogen and carbon monoxide into the intake of a variable compression ratio n-heptane fuelled HCCI, CFR engine were investigated. The variations in some of the key combustion and operational parameters were determined experimentally. These included cylinder pressure and its rise rate temporal developments, autoignition timing, combustion durations for both the low and high temperature reaction regions, COV values for IMEP and maximum cylinder pressure, and the incidence of knock and its intensity. In parallel with the experimental investigation, results of a numerical simulation of the processes involved obtained by employing a KIVA based approach while incorporating sufficiently detailed chemical kinetics are presented. It was found that supplementing n-heptane HCCI with gaseous fuels could inhibit the low temperature combustion region and delay to varying extents the high temperature combustion region. Methane admission produced lengthening of the delay to autoignition and extended the combustion durations. It is suggested that supplementing the liquid fuel with methane may be a means for controlling the combustion process of a liquid fuelled HCCI engine while obtaining higher power and acceptable levels of emissions without producing unacceptably heavy knock. However, the addition of hydrogen or carbon monoxide could not reduce the intensity of knock while improving power output.

INCINERATION FOR MUNICIPAL SOLID WASTE TREATMENT

2016 ◽  
Vol 9 (2) ◽  
Author(s):  
Manis Yuliani
Keyword(s):  
Air Pollution ◽  
Residence Time ◽  
Flue Gas ◽  
Energy Recovery ◽  
Treatment Process ◽  
Combustion Process ◽  
Recovery Process ◽  
Process Conditions ◽  
Gas Treatment ◽  
Pre Treatment

In order to reduce the accumulation of waste in landfill, incineration technology could becomes one of the solutions. In addition to reduce the volume of waste, the energy generated by incineration process can also be utilized. Plant Incineration consists of four categories process, namely pre-treatment process, combustion process, energy recovery process and flue gas treatment process (Air Pollution Control system). Pre-treatment process is used to increase the average calorific value of waste. Pre-treatment process depends on the type of incinerator used. Combustion process in an incinerator must accommodate the principles of 3 T (temperature, turbulence, time). Process conditions for the type of incinerator grate in accordance with the principle of 3 Tare the waste residence time in the grate less than 60 minutes, gas residence time more than 2 seconds and the gas temperature over 850 C. In the combustion process will produce heat carried by flue gas. The heat will flow into energy recovery process to be utilized. From energy recovery process, flue gas will enter into the APC system to reduce air pollution caused by combustion process.keywords : incinerator, waste, energy recovery

URANUS 52N

Alloy Digest ◽  
1994 ◽  
Vol 43 (5) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Flue Gas ◽  
Crevice Corrosion ◽  
Heat Treating ◽  
Flue Gas Desulfurization ◽  
Temperature Performance ◽  
Aisi Type ◽  
Better Than

Abstract URANUS 52N is a nitrogen-alloyed duplex stainless steel improved in stress-corrosion cracking resistance and with pitting and crevice corrosion resistance better than AISI Type 317L. Applications include handling phosphoric acid contaminated with chlorides and in flue gas desulfurization scrubbers. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-566. Producer or source: Creusot-Marrel.

AL 4565 ALLOY

Alloy Digest ◽  
2004 ◽  
Vol 53 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
High Resistance ◽  
Flue Gas ◽  
Heat Treating ◽  
Flue Gas Desulfurization ◽  
High Nitrogen ◽  
Temperature Performance ◽  
High Level

Abstract AL 4565 alloy has a high level of austenitizers, which provides the microstructure with a high resistance to sigma formation during welding. The high nitrogen also gives the alloy superior strength among the austenitics. Applications include flue gas desulfurization and handling seawater. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as heat treating and joining. Filing Code: SS-906. Producer or source: Allegheny Ludlum Corporation.

scholarly journals Investigation of the Heteroepitaxial Process Optimization of Ge Layers on Si (001) by RPCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 928
Author(s):  
Yong Du ◽  
Zhenzhen Kong ◽  
Muhammet Toprak ◽  
Guilei Wang ◽  
Yuanhao Miao ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Initial Growth ◽  
Two Dimensional ◽  
High Quality ◽  
Reduced Pressure

This work presents the growth of high-quality Ge epilayers on Si (001) substrates using a reduced pressure chemical vapor deposition (RPCVD) chamber. Based on the initial nucleation, a low temperature high temperature (LT-HT) two-step approach, we systematically investigate the nucleation time and surface topography, influence of a LT-Ge buffer layer thickness, a HT-Ge growth temperature, layer thickness, and high temperature thermal treatment on the morphological and crystalline quality of the Ge epilayers. It is also a unique study in the initial growth of Ge epitaxy; the start point of the experiments includes Stranski–Krastanov mode in which the Ge wet layer is initially formed and later the growth is developed to form nuclides. Afterwards, a two-dimensional Ge layer is formed from the coalescing of the nuclides. The evolution of the strain from the beginning stage of the growth up to the full Ge layer has been investigated. Material characterization results show that Ge epilayer with 400 nm LT-Ge buffer layer features at least the root mean square (RMS) value and it’s threading dislocation density (TDD) decreases by a factor of 2. In view of the 400 nm LT-Ge buffer layer, the 1000 nm Ge epilayer with HT-Ge growth temperature of 650 °C showed the best material quality, which is conducive to the merging of the crystals into a connected structure eventually forming a continuous and two-dimensional film. After increasing the thickness of Ge layer from 900 nm to 2000 nm, Ge surface roughness decreased first and then increased slowly (the RMS value for 1400 nm Ge layer was 0.81 nm). Finally, a high-temperature annealing process was carried out and high-quality Ge layer was obtained (TDD=2.78 × 107 cm−2). In addition, room temperature strong photoluminescence (PL) peak intensity and narrow full width at half maximum (11 meV) spectra further confirm the high crystalline quality of the Ge layer manufactured by this optimized process. This work highlights the inducing, increasing, and relaxing of the strain in the Ge buffer and the signature of the defect formation.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

scholarly journals Fire-Safe Polymer Composites: Flame-Retardant Effect of Nanofillers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 540
Author(s):  
Yukyung Kim ◽  
Sanghyuck Lee ◽  
Hyeonseok Yoon
Keyword(s):  
Organic Matter ◽  
High Temperature ◽  
Flame Retardant ◽  
Flame Retardants ◽  
Combustion Process ◽  
Polymeric Materials ◽  
Fire Performance ◽  
Gaseous Species ◽  
Advantages And Disadvantages ◽  
Temperature Conditions

Currently, polymers are competing with metals and ceramics to realize various material characteristics, including mechanical and electrical properties. However, most polymers consist of organic matter, making them vulnerable to flames and high-temperature conditions. In addition, the combustion of polymers consisting of different types of organic matter results in various gaseous hazards. Therefore, to minimize the fire damage, there has been a significant demand for developing polymers that are fire resistant or flame retardant. From this viewpoint, it is crucial to design and synthesize thermally stable polymers that are less likely to decompose into combustible gaseous species under high-temperature conditions. Flame retardants can also be introduced to further reinforce the fire performance of polymers. In this review, the combustion process of organic matter, types of flame retardants, and common flammability testing methods are reviewed. Furthermore, the latest research trends in the use of versatile nanofillers to enhance the fire performance of polymeric materials are discussed with an emphasis on their underlying action, advantages, and disadvantages.

Sign in / Sign up

Export Citation Format

Share Document