combustion temperature
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Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 550
Author(s):  
Guohai Jia ◽  
Guoshuai Tian ◽  
Daming Zhang

Taking a plateau high-pressure common-rail diesel engine as the research model, a model was established and simulated by AVL FIRE according to the structural parameters of a diesel engine. The combustion and emission characteristics of D, B20, and B50 diesel engines were simulated in the plateau atmospheric environment at 0 m, 1000 m, and 2000 m. The calculation results show that as the altitude increased, the peak in-cylinder pressure and the cumulative heat release of diesel decreased with different blending ratios. When the altitude increased by 1000 m, the cumulative heat release was reduced by about 5%. Furthermore, the emission trend of NO, soot, and CO was to first increase and then decrease. As the altitude increased, the mass fraction of NO emission decreased. As the altitude increased, the mass fractions of soot and CO increased. Additionally, when the altitude was 0 m and 1000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B20 were higher and more uniform. When the altitude was 2000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B50 were higher and more uniform. Lastly, as the altitude increased, the maximum combustion temperature of D and B20 decreased, and combustion became more uneven. As the altitude increased, the maximum combustion temperature of B50 increased, and the combustion became more uniform. As the altitude increased, the fuel–air ratio and the mass fractions of OH and NO decreased. When the altitude increased, the soot concentration increased, and the distribution area was larger.


2022 ◽  
Vol 9 ◽  
Author(s):  
Jinshuang Ma ◽  
Chuanjia Qi ◽  
Siyi Luo ◽  
Zongliang Zuo

The existence of inert gases such as N2 and CO2 in biogas will reduce the proportion of combustible components in syngas and affect the combustion and NOX formation characteristics. In this study, ANSYS CHEMKIN-PRO software combined with GRI-MECH 3.0 mechanism was used to numerically simulate the effects of different CO2 concentrations (CO2 volume ratio in biogas is 0–41.6%) on flame combustion temperature, flame propagation speed and nitrogen oxide formation of complex biogas with low calorific value. The results showed that when the combustion reaches the chemical equilibrium, the flame combustion temperature and flame propagation speed decrease with the increase of CO2 concentration, and the flame propagation speed decreases even more slowly. Meanwhile, the molar fraction of NO at chemical equilibrium decreases with the increase of CO2 concentration and the decrease is decreasing, which indicates that the effect of CO2 concentration in biogas on NO is simpler. While the molar fraction of NO2 does not change regularly with the change of CO2 concentration, the effect of CO2 concentration in biogas on NO2 is complicated. The highest molar fraction of NO2 was found at chemical equilibrium when the CO2 concentration was 33.6%, when the target was a typical low calorific value biogas.


Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Sofiya Aydinyan ◽  
Suren Kharatyan ◽  
Irina Hussainova

Modeling the self-sustained high-temperature synthesis (SHS) reaction via thermal dilution and transformation of the reaction heterogeneous media into a moderate exothermic one has unlimited potential for designing inorganic powders of a certain morphology beneficial for advanced consolidation. Thermal/inert dilution of the high-exothermic mixtures leads to the fluent decrease of both the combustion temperature and velocity, thus allowing to tailor the thermal regime of the combustion process, therewith contributing to high yield of reaction and governing the microstructural features of the combustion products. In the current review, we shed on light on the possibilities of this effective strategy to control the thermal behavior of the SHS process for the preparation of applicable powder precursors for the subsequent successful sintering. Since the SHS process of some refractory ceramics (MoSi2, TiB2, TiC, etc.) involves a relatively violent reaction rate and high combustion temperature, achieving a high level of microstructure control in these systems is often challenging. The challenge was tackled with a thermal dilution approach, attaining considerable enhancement in the homogeneity among phases with an increase of diluent content along with microstructure refinement.


2021 ◽  
Vol 9 ◽  
Author(s):  
Yanhui Niu ◽  
Wenbin Yu ◽  
Shuguang Yang ◽  
Quan Wan

The pyrolytic behavior of organic matter inside nanopores was studied by simultaneous thermogravimetric/differential scanning calorimetry analyzer coupled with Fourier transform infrared spectroscopy (STA/TG-FTIR). Nanoporous silica was prepared by a hydrothermal method using long-chain alkyl quaternary ammonium bromide (CnTAB, n = 12, 14) as a template. The pyrolytic behavior of CnTAB inside nanopores with different diameters was investigated and compared with that of CnTAB inside and outside nanopores. The results showed that the pyrolytic removal process consisted of the following features: 1) CnTAB underwent carbon chain decomposition and oxidation; 2) the DSC exothermal peak of CnTAB came mainly from its oxidative combustion, and the oxidative combustion temperature decreased with increasing pore size; 3) the CnTAB inside nanopores underwent crystallization–amorphous state phase transition, and CnTAB got trapped inside the calcined nanopores. In addition, the pyrolytic behavior of CnTAB inside the calcined nanopores was found to be similar to that of the uncalcined nanopores. This study aims to understand the storage and transformation processes of organic hydrocarbons under nanopore-confinement effect.


2021 ◽  
Vol 9 (4) ◽  
pp. 179
Author(s):  
Arinda Dwi Arafah ◽  
Soni Sisbudi Harsono

Briquette is an alternative simple fuel that has a relatively high calorific value, so it has the potential to reduce the use of firewood and fuel oil (BBM). Herbal waste is one of the biomass materials that came from the rest of the material in the production of herbal medicine made from medicinal plants. Utilization of herbal dregs as briquettes has been implemented by PT. Industri Jamu dan Farmasi Sido Muncul. Tbk, as fuel for boiler engines. Making briquettes from biomass requires the addition of materials, one of which is coconut shell charcoal and adhesives such as molasses and tapioca flour to improve the physical properties of the briquettes. Briquettes with good quality have a maximum moisture content and ash content of 8%, a heating value of more than 5000 cal/gram, a constant combustion temperature of 350℃ for a long period of time and is easily flammable. The purpose of this study was to determine the characteristics of briquettes based on the value of water content, ash content, combustion temperature, combustion rate, and calorific value. Variable treatment with the addition of coconut shell charcoal with several doses of 10%, 20%, and 30% and variations of adhesive materials. Data analysis was performed by using two-factor ANOVA statistical test. The results showed that briquettes with tapioca flour adhesive and 30% coconut shell charcoal composition had the best characteristics of briquettes compared to other variations.


2021 ◽  
Vol 943 (1) ◽  
pp. 012014
Author(s):  
Jingyin Liu ◽  
Zhijun Peng

Abstract As regulations for controlling VOCs (Volatile Organic Compounds) emissions have become more and more stringent, RTO (Regenerative Thermal Oxidizer) which involves heat exchange and storage, combustion and reaction processes has to be further optimised for enhancing the VOC treatment efficiency and reducing energy consumption. In this paper, influences of operating temperature distributions and internal flow fields on gas-out VOC concentration have been studied with experimental investigation and CFD numerical simulation. Experimental results shows that combustion temperature (around the combustor) plays more critical role than thermal storage bed temperature for affecting VOC flow-out concentration. By examining the internal flow and temperature distributions, modelling results demonstrate that fast heat transfer takes place in thermal ceramic beds and high temperature areas are formed around the combustor. At about 20 seconds after a bed working for gas-in flow, the heat transfer has demonstrated obvious attenuating. The research suggests that it is very challenging for simultaneously maintaining low gas-out VOC concentration and keeping low fuel consumption and low combustion temperature in RTOs.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yong Ho Kim ◽  
Sarah H. Warren ◽  
Ingeborg Kooter ◽  
Wanda C. Williams ◽  
Ingrid J. George ◽  
...  

Abstract Background Open burning of anthropogenic sources can release hazardous emissions and has been associated with increased prevalence of cardiopulmonary health outcomes. Exposure to smoke emitted from burn pits in military bases has been linked with respiratory illness among military and civilian personnel returning from war zones. Although the composition of the materials being burned is well studied, the resulting chemistry and potential toxicity of the emissions are not. Methods Smoke emission condensates from either flaming or smoldering combustion of five different types of burn pit-related waste: cardboard; plywood; plastic; mixture; and mixture/diesel, were obtained from a laboratory-scale furnace coupled to a multistage cryotrap system. The primary emissions and smoke condensates were analyzed for a standardized suite of chemical species, and the condensates were studied for pulmonary toxicity in female CD-1 mice and mutagenic activity in Salmonella (Ames) mutagenicity assay using the frameshift strain TA98 and the base-substitution strain TA100 with and without metabolic activation (S9 from rat liver). Results Most of the particles in the smoke emitted from flaming and smoldering combustion were less than 2.5 µm in diameter. Burning of plastic containing wastes (plastic, mixture, or mixture/diesel) emitted larger amounts of particulate matter (PM) compared to other types of waste. On an equal mass basis, the smoke PM from flaming combustion of plastic containing wastes caused more inflammation and lung injury and was more mutagenic than other samples, and the biological responses were associated with elevated polycyclic aromatic hydrocarbon levels. Conclusions This study suggests that adverse health effects of burn pit smoke exposure vary depending on waste type and combustion temperature; however, burning plastic at high temperature was the most significant contributor to the toxicity outcomes. These findings will provide a better understanding of the complex chemical and combustion temperature factors that determine toxicity of burn pit smoke and its potential health risks at military bases.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Erdiwansyah ◽  
Mahidin ◽  
Husni Husin ◽  
Muhammad Faisal ◽  
Muhtadin ◽  
...  

Investigation of combustion temperature through experiments with a wide range of fuels, both solid and liquid, is continuously being conducted by scientists around the world, while the measurement of heat transfer rate can be analyzed when the combustion process occurs. Previous research has generally been conducted using liquefied gas, fossil fuels, and alcohol additives. Specifically, the research in this work investigated the convection heat rate and combustion temperature through the modification of the perforated plate. The experiment was conducted in the fluidized-bed combustor (FBC) fuel chamber using solid waste fuel of oil palm biomass. Measurements were performed at four different points using the HotTemp HT-306 Digital Thermometer. The results of the experiment showed that the convection heat rate in measurement one (M-I) reached 8.258 W/m2 for palm kernel shell (PKS) fuel. Meanwhile, in measurement two (M-II), the convection rate of 7.392 W/m2 was produced by oil palm midrib (OPM) fuel. The highest combustion temperature was recorded with OPM fuel (884°C) at M-I. However, the combustion temperature of the PKS combustion process is higher at 896°C but shows a less good trend than OPM. Overall, the measurement results of the three types of fuel used to modify the perforated plate applied in the FBC fuel chamber are excellent. It can be proven that the fuel is put into the combustion chamber with nothing left.


2021 ◽  
pp. 146808742110601
Author(s):  
Ming Jia ◽  
Jinpeng Bai ◽  
Huiquan Duan ◽  
Yaopeng Li ◽  
Yikang Cai ◽  
...  

The potential of reactivity controlled compression ignition (RCCI) combustion fueled with hydrogen and diesel (i.e. hydrogen/diesel RCCI) was evaluated using multi-dimensional simulations embedded with a reduced chemical mechanism. In hydrogen/diesel RCCI, the premixed hydrogen is ignited by the diesel, which is directly injected into the cylinder well before the top dead center. To investigate the potential benefits of hydrogen/diesel RCCI, its combustion characteristics were compared with that of gasoline/diesel RCCI from the perspective of the second law of thermodynamics. Meanwhile, the impacts of premixed energy ratio and initial pressure on the exergy distribution for hydrogen/diesel RCCI were explored. The results show that hydrogen/diesel RCCI has an advantage over gasoline/diesel RCCI in the reduction of exergy destruction due to higher combustion temperature, shorter combustion duration, and the distinctive oxidation pathways between hydrogen and gasoline. A higher proportion of exergy output work can be achieved for hydrogen/diesel RCCI under the conditions with the same total input energy and 50% heat release (CA50) point. Moreover, a larger premixed energy ratio (i.e. larger hydrogen proportion) is helpful to elevate exergy output work and reduce exergy destruction owing to higher combustion temperature and the undergoing oxidation pathways of hydrogen with less exergy destruction. A higher initial pressure yields raised exergy destruction because of lower combustion temperature and longer combustion duration, but exergy output work is increased owing to the significantly reduced exergy transfer through heat transfer.


2021 ◽  
Vol 9 ◽  
Author(s):  
Haili Liu ◽  
Qingchao Hong ◽  
Heyun Liu ◽  
Zhen Huang ◽  
Xu Zhang ◽  
...  

Fast-growing grass, as a popular renewable energy, is low in sulfur content, so NOx is the major pollutant during its combustion. To study the emission characteristics of NOx and obtain the data of controlling NOx emission, the effects of combustion temperature as well as the additive type and mass fraction were investigated on the emission characteristics of NOx from the combustion of fast-growing grass. Results revealed that the first peak for NOx emission from this combustion gradually increases with an increase in temperature. Moreover, the additives were found to dramatically impact the amount of NOx emission and its representative peak. The optimal additives and their optimal mass fractions were determined at various specific temperatures to reduce NOx emission. At combustion temperatures of 600, 700, 750, 800, and 850°C, the optimal conditions to limit NOx emissions were 5% SiO2, 3% Al2O3, 3% Ca(OH)2, 15% Al2O3, and 3% SiO2 (or 3% Al2O3), respectively; the corresponding emission peaks decreased by 43.59, 44.21, 47.99, 24.18, and 30.60% (or 31.51%), with denitration rates of 63.28, 50.34, 57.44, 27.05, and 27.34% (or 27.28%), respectively.


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