Edelgasthermometrie im Tiefenwasser des Kivusees mit Löslichkeiten von Edelgasen bei höheren Temperaturen

2021 ◽  
Author(s):  
Cornelis Schwenk ◽  
Sophie Negele ◽  
Florian Freundt ◽  
Werner Aeschbach ◽  
Bertram Boehrer
Keyword(s):  
Excess Air

<p>In natürlichen Gewässern werden Edelgaskonzentrationen häufig zur Bestimmung der Umgebungstemperaturen beim letzten intensiven Kontakt zur Atmosphäre (Äquilibration) verwendet. Dieses Verfahren nennt sich <em>Edelgasthermometrie </em>und wird unter anderem genutzt, um Grundwasserbildungstemperaturen und historische Temperaturschwankungen quantitativ zu bestimmen. Da bisher nur übliche Bildungstemperaturen von unter 35°C bekannt sind, hat man sich mit Löslichkeiten bis zu dieser Temperatur begnügt. Es gibt jedoch verschiedene Prozesse, wie etwa vulkanische Aktivität, die hohe Wassertemperaturen erzeugen können. Wir haben daher die Löslichkeiten von Edelgasen bei höheren Temperaturen bestimmt und diese mit Daten aus der Literatur kombiniert, um neue Löslichkeitsfunktionen zu generieren die den gesamten Bereich von 0 bis 80°C abdecken. Wir verwenden diese Funktionen, um publizierte Messungen der Edelgaskonzentrationen im Tiefenwasser des Kivusees zu analysieren, die ungewöhnlich niedrig sind. Der Kivusee liegt am Rande des Nyiragongo-Vulkans und speichert große Mengen an Kohlendioxid und Methan, die bei einer Ausgasung für die umliegende Bevölkerung tödlich wären. Vor allem jetzt, wo die industrielle Ausbeutung der Gaslagerstätte in die Schichtung des Sees eingreift ist es wichtig, die Dynamiken des Sees zu verstehen und nachzuvollziehen, woher das Defizit an Edelgasen stammt. Wir nutzen Edelgaskonzentrationen, -verhältnisse und kleinste-Quadrate-Approximation mit <em>Excess-air</em>, um Bildungstemperaturen abzuleiten. Am besten lassen sich die niedrigen Edelgaskonzentrationen mit einer atmosphärischen Äquilibrierung des Tiefenwassers bei ca. 60°C erklären, wobei dann nur ein minimales Defizit an Edelgasen übrig bleibt. Damit liefern die Edelgasdefizite KEINEN Hinweis auf eine frühere Entgasung des Sees. </p>

Effect of Chemical Hythane Composition on Pressure in Combustion Chamber of Engine

2019 ◽  
pp. 36-42
Author(s):  
A. P. Shaikin ◽  
I. R. Galiev
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Power Plants ◽  
Engine Speed ◽  
Combustion Engine ◽  
Fuel Mixture ◽  
Maximum Pressure ◽  
Chamber Volume ◽  
Excess Air ◽  
Scientific Papers

The article analyzes the influence of chemical composition of hythane (a mixture of natural gas with hydrogen) on pressure in an engine combustion chamber. A review of the literature has showed the relevance of using hythane in transport energy industry, and also revealed a number of scientific papers devoted to studying the effect of hythane on environmental and traction-dynamic characteristics of the engine. We have studied a single-cylinder spark-ignited internal combustion engine. In the experiments, the varying factors are: engine speed (600 and 900 min-1), excess air ratio and hydrogen concentration in natural gas which are 29, 47 and 58% (volume).The article shows that at idling engine speed maximum pressure in combustion chamber depends on excess air ratio and proportion hydrogen in the air-fuel mixture – the poorer air-fuel mixture and greater addition of hydrogen is, the more intense pressure increases. The positive effect of hydrogen on pressure is explained by the fact that addition of hydrogen contributes to increase in heat of combustion fuel and rate propagation of the flame. As a result, during combustion, more heat is released, and the fuel itself burns in a smaller volume. Thus, the addition of hydrogen can ensure stable combustion of a lean air-fuel mixture without loss of engine power. Moreover, the article shows that, despite the change in engine speed, addition of hydrogen, excess air ratio, type of fuel (natural gas and gasoline), there is a power-law dependence of the maximum pressure in engine cylinder on combustion chamber volume. Processing and analysis of the results of the foreign and domestic researchers have showed that patterns we discovered are applicable to engines of different designs, operating at different speeds and using different hydrocarbon fuels. The results research presented allow us to reduce the time and material costs when creating new power plants using hythane and meeting modern requirements for power, economy and toxicity.

Modeling and Experiment on Combustion Characteristics for Biomass Rotary Burner

2020 ◽  
Vol 04 ◽  
Author(s):  
Guohai Jia ◽  
Lijun Li ◽  
Li Dai ◽  
Zicheng Gao ◽  
Jiping Li
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Combustion Efficiency ◽  
Middle Part ◽  
Combustion Characteristics ◽  
Maximum Temperature ◽  
Excess Air ◽  
Element Simulation ◽  
Excess Air Coefficient ◽  
Secondary Air

Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established. Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed. Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber. Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.

Effect of thermal input, excess air coefficient and combustion mode on natural gas MILD combustion in industrial-scale furnace

Fuel ◽  
2021 ◽  
Vol 302 ◽  
pp. 121179
Author(s):  
Mingming Huang ◽  
Ruichuan Li ◽  
Jikang Xu ◽  
Shen Cheng ◽  
Haoxin Deng ◽  
...  
Keyword(s):  
Natural Gas ◽  
Industrial Scale ◽  
Combustion Mode ◽  
Mild Combustion ◽  
Excess Air ◽  
Excess Air Coefficient

Integrated analysis of the excess air on steam power plant CFB boiler using mathematical and CFD modeling

2018 ◽  
Author(s):  
Hariyotejo Pujowidodo ◽  
Ahmad Indra Siswantara ◽  
Budiarso ◽  
Asyari Daryus ◽  
Gun Gun Ramdlan Gunadi
Keyword(s):  
Power Plant ◽  
Cfd Modeling ◽  
Integrated Analysis ◽  
Steam Power ◽  
Cfb Boiler ◽  
Steam Power Plant ◽  
Excess Air

Noble gas recharge temperatures and the excess air component

1997 ◽  
Vol 12 (6) ◽  
pp. 747-762 ◽  
Author(s):  
G.B. Wilson ◽  
G.W. McNeill
Keyword(s):  
Noble Gas ◽  
Excess Air

Economy and emission characteristics of the optimal dilution strategy in lean combustion based on GDI gasoline engine equipped with prechamber

2021 ◽  
Vol 13 (12) ◽  
pp. 168781402110381
Author(s):  
Li Wang ◽  
Zhaoming Huang ◽  
Wang Tao ◽  
Kai Shen ◽  
Weiguo Chen
Keyword(s):  
Fuel Economy ◽  
Gasoline Engine ◽  
Direct Injection ◽  
Engine Performance ◽  
Gasoline Direct Injection ◽  
Dilution Ratio ◽  
Lean Combustion ◽  
Excess Air ◽  
Combustion Phase ◽  
Hc Emissions

EGR and excess-air dilution have been investigated in a 1.5 L four cylinders gasoline direct injection (GDI) turbocharged engine equipped with prechamber. The influences of the two different dilution technologies on the engine performance are explored. The results show that at 2400 rpm and 12 bar, EGR dilution can adopt more aggressive ignition advanced angle to achieve optimal combustion phasing. However, excess-air dilution has greater fuel economy than that of EGR dilution owing to larger in-cylinder polytropic exponent. As for prechamber, when dilution ratio is greater than 37.1%, the combustion phase is advanced, resulting in fuel economy improving. Meanwhile, only when the dilution ratio is under 36.2%, the HC emissions of excess-air dilution are lower than the original engine. With the increase of dilution ratio, the CO emissions decrease continuously. The NOX emissions of both dilution technologies are 11% of those of the original engine. Excess-air dilution has better fuel economy and very low CO emissions. EGR dilution can effectively reduce NOX emissions, but increase HC emissions. Compared with spark plug ignition, the pre chamber ignition has lower HC, CO emissions, and higher NO emissions. At part load, the pre-chamber ignition reduces NOX emissions to 49 ppm.

Research on the Realization of the Maximum Benefit of Thermal Power

2015 ◽  
Vol 713-715 ◽  
pp. 660-663
Author(s):  
Jia Min Chen
Keyword(s):  
Real Time ◽  
Oxygen Content ◽  
Thermal Power ◽  
Balance Method ◽  
Excess Air ◽  
Maximum Benefit ◽  
Function Expression ◽  
New Variables ◽  
The Relationship

First, Anti-balance method is used to build the model of q2,q3,q4 to figure out the Function expression of q2+q3+q4 .when q2+q3+q4 gets the minimum, the corresponded to the excess air ratio is the best excess air ratio. The excess air ratio is related to the load of boiler, so the function image describing the relationship between q2+q3+q4 and excess air ratio under the different load of 192.3MW, 215.8MW, 245.3MW and 298MW are made to get the best excess air ratio. Second, based on the model before, new variables q5 and q6 are added to complete the function formula of the efficiency and the excess air ratio, and four function image will be drew to show the tends. Finally, based on the conclusions above, smoke vents oxygen content can take the place of excess air ratio to achieve the purpose of monitoring the boiler in real time.

Co-Combustion of Coal With Rice Husk and Bamboo in Power Generation

2007 ◽  
Author(s):  
Christopher Y. H. Chao ◽  
Philip C. W. Kwong ◽  
J. H. Wang
Keyword(s):  
Rice Husk ◽  
Power Plants ◽  
Fuel Mixture ◽  
Volatile Matter ◽  
Pollutant Emissions ◽  
Energy Output ◽  
Pollutant Emission ◽  
Firing Process ◽  
Excess Air ◽  
Unit Energy

In many Asian countries Coal is frequently used a major fuel in power plants. Burning coal creates quite a lot of environmental problems when compared to other cleaner fuels such as natural gas. Experimental study of co-combustion of coal and biomass was conducted in a laboratory scale combustion facility to evaluate the combustion and pollutant emission performance under different operation parameters. Rice husk and bamboo were used as the biomass fuels in this study. This paper reported the influence of the biomass blending ratio in the fuel mixture and the excess air ratio on the combustion behavior. It was noted that the combustion temperature and the energy output from the co-firing process were reduced compared to coal combustion alone owing to the fact that biomass has lower heating value compared to coal. However, the high volatile matter (VM) content of biomass improved the combustion time scale so that the carbon monoxide (CO) emissions were reduced substantially. In addition, the fuel nitrogen and sulfur content in biomass were lower than that of coal and hence suppressed the formation of nitrogen oxides (NOx) and sulfur dioxide (SO2) during the cocombustion process. The increase of excess air ratio also affected most of the pollutant emissions. The pollutant emission per unit energy output at different excess air ratios and biomass blending ratios were studied in detail in this paper. Attention should be paid to the high potential of slagging and fouling in the boiler when co-firing coal with biomass.

Effects of Air Flowrate on the Combustion and Emissions of Blended Corn Straw and Pinewood Wastes

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Honghua Zhao ◽  
Rui Sun ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ignition Delay Time ◽  
Fixed Bed ◽  
Combustion Efficiency ◽  
Fixed Bed Reactor ◽  
Corn Straw ◽  
Excess Air ◽  
Burning Rates ◽  
Excess Air Coefficient ◽  
Hazardous Pollutants

This research investigated the effects of the specific primary (under-fire) air flowrate (m˙air) on the combustion behavior of a 50–50 wt % blend of raw corn straw (CS) and raw pinewood wastes in a fixed-bed reactor. This parameter was varied in the range of 0.079–0.226 kg m−2 s−1, which changed the overall combustion stoichiometry from air-lean (excess air coefficient λ = 0.73) to air-rich (excess air coefficient λ = 1.25) and affected the combustion efficiency and stability as well as the emissions of hazardous pollutants. It was observed that by increasing m˙air, the ignition delay time first increased and then decreased, the average bed temperatures increased, both the average flame propagation rates and the fuel burning rates increased, and the combustion efficiencies also increased. The emissions of CO as well as those of cumulative gas phase nitrogen compounds increased, the latter mostly because of increasing HCN, while those of NO were rather constant. The emissions of HCl decreased but those of other chlorine-containing species increased. The effect of m˙air on the conversion of sulfur to SO2 was minor. By considering all of the aforesaid factors, a mildly overall air-rich (fuel-lean) (λ = 1.04) operating condition can be suggested for corn-straw/pinewood burning fixed-bed grate-fired reactors.

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