scholarly journals A kinetic evaluation on no2 formation in the post-flame region of pressurized oxy-combustion process

2020 ◽  
pp. 236-236
Author(s):  
Xuebin Wang ◽  
Gaofeng Dai ◽  
Gregory Yablonsk ◽  
Milan Vujanovic ◽  
Richard Axelbaum
Keyword(s):  
Power Plants ◽  
Combustion Process ◽  
Strong Acid ◽  
Dew Point ◽  
Kinetic Evaluation ◽  
Atmospheric Air ◽  
Energy Penalty ◽  
Flame Region ◽  
No2 Formation ◽  
Time Required

Pressurized oxy-combustion is a promising technology that can significantly reduce the energy penalty associated with first generation oxy-combustion for CO2 capture in coal-fired power plants. However, higher pressure enhances the production of strong acid gases, including NO2 and SO3, aggravating the corrosion threat during flue gas recirculation. In the flame region, high temperature NOx exists mainly as NO, while conversion from NO to NO2 happened in post-flame region. In this study, the conversion of NO ? NO2 has been kinetically evaluated under representative post-flame conditions of pressurized oxy-combustion after validating the mechanism (80 species and 464 reactions), which includes nitrogen and sulfur chemistry based on GRI-Mech 3.0. The effects of residence time, temperature, pressure, major species (O2/H2O), and minor or trace species (CO/SOx) on NO2 formation are studied. The calculation results show that when pressure is increased from 1 to 15 bar, NO2 is increased from 1 to 60 ppm, and the acid dew point increases by over 80?C. Higher pressure and temperature greatly reduce the time required to reach equilibrium, e.g., at 15 bar and 1300?C, equilibrium is reached in 1 millisecond and the NO2/NO is about 0.8%. The formation and destruction of NO2 is generally through the reversible reactions: NO+O+M=NO2+M, HO2+NO=NO2+OH, and NO+O2=NO2+O. With increasing pressure and decreasing temperature, O plays a much more important role than HO2 in the oxidation of NO. A higher water vapor content accelerates NO2 formation in all cases by providing more O and HO2 radicals. The addition of CO or SO2 also promotes the formation of NO2. Finally, NO2 formation in a Pressurized oxy-combustion furnace is compared with that in a practical atmospheric air-combustion furnace and the comparison show that NO2 formation in a Pressurized oxy-combustion furnace can be over 10 times that of an atmospheric air-combustion furnace.

The territory of the Russian Federation is a rescue from the COVID-19 coronavirus

2020 ◽  
pp. 26-29
Author(s):  
Yu. Kozlov ◽  
R. Serebryakov
Keyword(s):  
Wind Power ◽  
Rural Areas ◽  
Small Area ◽  
Power Plants ◽  
Air Spring ◽  
Atmospheric Air ◽  
Large Cities ◽  
Wind Power Plants ◽  
The World ◽  
The Russian Federation

A new coronavirus pandemic is raging all over the world, especially in densely populated areas. Unlike most countries, more than half of the territory of Russia is not used by humans — which means that it is possible to settle large cities to avoid crowding people on a small area. The authors of the article consider wind power, namely vortex wind power plants, as a new source of energy that can be quickly and with less harm built in rural areas. The article also discusses the possibilities of an alternative Autonomous non-volatile installation "Air spring" for obtaining fresh water from atmospheric air.

scholarly journals Co-Combustion Studies of Low-Rank Coal and Refuse-Derived Fuel: Performance and Reaction Kinetics

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3796
Author(s):  
Mudassar Azam ◽  
Asma Ashraf ◽  
Saman Setoodeh Setoodeh Jahromy ◽  
Sajjad Miran ◽  
Nadeem Raza ◽  
...  
Keyword(s):  
Activation Energy ◽  
Waste Management ◽  
Energy Demand ◽  
Power Plants ◽  
Combustion Process ◽  
Isoconversional Methods ◽  
Low Rank ◽  
Heating Rates ◽  
Average Activation Energy ◽  
Refuse Derived Fuel

In connection to present energy demand and waste management crisis in Pakistan, refuse-derived fuel (RDF) is gaining importance as a potential co-fuel for existing coal fired power plants. This research focuses on the co-combustion of low-quality local coal with RDF as a mean to reduce environmental issues in terms of waste management strategy. The combustion characteristics and kinetics of coal, RDF, and their blends were experimentally investigated in a micro-thermal gravimetric analyzer at four heating rates of 10, 20, 30, and 40 °C/min to ramp the temperature from 25 to 1000 °C. The mass percentages of RDF in the coal blends were 10%, 20%, 30%, and 40%, respectively. The results show that as the RDF in blends increases, the reactivity of the blends increases, resulting in lower ignition temperatures and a shift in peak and burnout temperatures to a lower temperature zone. This indicates that there was certain interaction during the combustion process of coal and RDF. The activation energies of the samples were calculated using kinetic analysis based on Kissinger–Akahira–Sunnose (KAS) and Flynn–Wall–Ozawa (FWO), isoconversional methods. Both of the methods have produced closer results with average activation energy between 95–121 kJ/mol. With a 30% refuse-derived fuel proportion, the average activation energy of blends hit a minimum value of 95 kJ/mol by KAS method and 103 kJ/mol by FWO method.

scholarly journals On the relative attractions of sulphuric acid for water, under particular circumstances: with suggestion of means of improving the ordinary process of manufacturing sulphuric acid

1843 ◽  
Vol 4 ◽  
pp. 81-82
Keyword(s):  
High Temperature ◽  
Specific Gravity ◽  
Sulphuric Acid ◽  
Conclusive Evidence ◽  
Dew Point ◽  
Chemical Affinity ◽  
Dilute Acid ◽  
Atmospheric Air ◽  
Open Atmosphere ◽  
Series Of Experiments

The object of the inquiry detailed in the present paper is to determine at what degree of concentration the affinity of sulphuric acid for aqueous vapour is equal to that of anhydrous space for the same vapour at given temperatures. It has long been known that concentrated sulphuric acid abstracts moisture from the atmosphere, but the amount and the rate of this absorption have never been ascertained with accuracy; and consequently, in applying this acid to purposes of exsiccation, the experimenter has often been at a loss to know whether the acid was sufficiently strong to render the space in which it was confined perfectly anhydrous. By placing portions of the acid, previously weighed, and diluted with known quantities of water, under the receiver of an air-pump, with equal portions of concentrated acid, of the specific gravity 1·8428, in similar dishes, the author ascertained that the dilute acid could be concentrated to the specific gravity 1·814, at a temperature varying from 65° to 57°: whence he concludes that acid of such strength is capable of drying a vacuum when the temperature does not exceed 57°. By making similar experiments in air, the author compared together the weights lost by ten grains of dilute sulphuric acid of the specific gravity 1·135, at three different periods of the day for six days, taking note of the dew-point and the temperature; and infers that when the affinity of space for vapour, or the evaporating force, is equal to 0·15 of an inch of mercury, it is just able to balance the affinity for water of sulphuric acid of the specific gravity 1·249. The author next instituted a series of experiments to ascertain whether the evaporation of water from dilute sulphuric acid is capable of being carried on to the same extent in air as in vacuo, and found that the evaporating force of air exerted upon such acid is less than that of a vacuum at the same temperature. He observes that his experiments offer conclusive evidence that the evaporation of water is not owing to the existence of a chemical affinity between the vapour of the liquid and atmospheric air; but thinks that they favour the notion that the obstruction to this process in the open atmosphere is rather owing to the pressure than to the inertiæ of the particles of air. He is also of opinion that improvements will hereafter arise from this inquiry with regard to the economical management of the process of manufacturing sulphuric acid, which process would be greatly expedited by the regulated admission of steam into the condensing chambers kept at a constant high temperature.

Oxidative decomposition properties of cationic exchange resins producing SO42− in power plants

2015 ◽  
Vol 71 (10) ◽  
pp. 1478-1484
Author(s):  
Zhiping Zhu ◽  
Chenlin Dai ◽  
Sen Liu ◽  
Ye Tian
Keyword(s):  
Data Analysis ◽  
Organic Carbon ◽  
Power Plants ◽  
Strong Acid ◽  
Residual Chlorine ◽  
Sulphate Content ◽  
Cationic Exchange ◽  
Exchange Resins ◽  
Dynamic Cycle ◽  
Decomposition Properties

The sulphate content of a system increases when strong-acid cationic exchange resins leak into a system or when sulphonic acid groups on the resin organic chain detach. To solve this problem, a dynamic cycle method was used in dissolution experiments of several resins under H2O2 or residual chlorine conditions. Results show that after performing dynamic cycle experiments for 120 hours under oxidizing environments, the SO42− and total organic carbon (TOC) released by four kinds of resins increased with time, contrary to their release velocity. The quantity of released SO42− increased as the oxidizing ability of oxidants was enhanced. Results showed that the quantity and velocity of released SO42− under residual chlorine condition were larger than those under H2O2 condition. Data analysis of SO42− and TOC released from the four kinds of resins by the dynamic cycle experiment revealed that the strength of oxidation resistance of the four resins were as follows: 650C > 1500H > S200 > SP112H.

Analysis of the Variable Cross-Section Duct and Straightening Device Geometry Effects on the Hydrogen Combustion Process

2021 ◽  
pp. 62-71
Author(s):  
O.V. Guskov ◽  
V.S. Zakharov ◽  
Minko
Keyword(s):  
Combustion Chamber ◽  
Cross Section ◽  
High Speed ◽  
Power Plants ◽  
Combustion Process ◽  
Variable Cross Section ◽  
Hydrogen Combustion ◽  
Variable Cross ◽  
Calculation Methods ◽  
Transition Channel

The development and research of high-speed aircrafts and their individual parts is an urgent scientific task. In the scientific literature there is information about the integral characteristics of aircrafts of this type, but there is no detailed consideration of such an important part as the transition channel between the air intake and the combustion chamber. The article considers several flow path configurations. The numerical simulation results of hydrogen combustion in the channels of variable cross section using a detailed kinetic mechanism are presented. Based on the analysis of the data obtained, the models of the transition channel and the combustion chamber showing the best characteristics were selected. The impulse and the fuel combustion efficiency are used as criteria for comparing the flow paths. The difference in the application of two calculation methods is described. The presented results and calculation methods can be used at the stage of computational research of the working processes in advanced power plants.

Rapid and Efficient Wet Fixation by the Use of Steam

1969 ◽  
Vol 39 (6) ◽  
pp. 497-504 ◽  
Author(s):  
Norman R. S. Hollies ◽  
Steven R. Chafitz ◽  
Karen A. Farquhar
Keyword(s):  
Fiber Surface ◽  
Strong Acid ◽  
Strength Properties ◽  
Fiber System ◽  
Resin Solution ◽  
Speed Up ◽  
Drying Properties ◽  
The Individual ◽  
Time Required ◽  
Finishing Processes

The impregnation of cotton fabrics with a solution consisting of strong acid and a combination of N-methylol resins having polymer-forming and cross-linking properties distinguishes the wet-fixation system from conventional durable-press processes, and this finish results in an improved balance of smoothness and strength properties during wear and laundering. Swelling of the fibers in a steam atmosphere, following padding in the resin solution can serve to speed up the impregnation process. In addition, with controls to minimize resin migration back to the fiber surface, steaming can substantially improve the efficiency of the use of resin for producing these smooth drying properties. The degree of penetration of resin is influenced by a number of process variables, such as predrying before steaming, steaming time, fabric tension and rapidity of neutralization. The optimum in fabric performance is achieved with both sufficient resin of both types in the fiber system and even distribution of resin within the individual fibers, Steaming acts to improve both these factors over that achieved in conventional hot wet fixation and so reduces the time required for wet fixation by a factor of 20–30. There is a corresponding increase in efficiency of resin use so that resin solids in the bath can be reduced two- to three-fold. These findings appear to have general application to a variety of cotton finishing processes involving fiber impregnation with reactive resins.

The Cause and Forecasting of Ice Fogs *

1953 ◽  
Vol 34 (9) ◽  
pp. 397-400 ◽  
Author(s):  
H. Appleman
Keyword(s):  
Relative Humidity ◽  
Low Temperature ◽  
Combustion Process ◽  
Hydrocarbon Fuels ◽  
Dew Point ◽  
The Other ◽  
Sudden Increase ◽  
Minimum Frequency ◽  
Ice Fog ◽  
Rare Phenomenon

Studies carried out in Alaska and Canada have shown that fog is a relatively rare phenomenon at temperatures between 0° and − 30°F, with a minimum frequency between − 20° and −30°. At still lower temperatures, however, the frequency of fog increases rapidly. This effect is noted only in the immediate vicinity of inhabited areas, such as towns and airfields. The reason for the sudden increase in fog frequency at these temperatures, and the rarity or lack of fog at the higher temperatures, has not been heretofore explained. In a recent study on aircraft condensation trails, it was shown that if the temperature is sufficiently low (between − 20 and − 40°F, depending on the relative humidity), the burning of hydrocarbon fuels, such as would occur in towns and at airfields, easily results in supersaturation of the air and a “surface contrail” or ice fog. At higher temperatures, on the other hand, combustion actually reduces the relative humidity of the atmosphere, hindering the formation of fog. In this paper it is shown that low-temperature (ice) fogs form as a result of the combustion process, and curves are presented showing the temperature-dew-point relationship necessary for the formation of such fogs.

scholarly journals Preliminary Performance and Cost Evaluation of Four Alternative Technologies for Post-Combustion CO2 Capture in Natural Gas-Fired Power Plants

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 543 ◽  
Author(s):  
Manuele Gatti ◽  
Emanuele Martelli ◽  
Daniele Di Bona ◽  
Marco Gabba ◽  
Roberto Scaccabarozzi ◽  
...  
Keyword(s):  
Supersonic Flow ◽  
Natural Gas ◽  
Co2 Capture ◽  
Power Plants ◽  
Combined Cycle ◽  
Cost Evaluation ◽  
Base Case ◽  
Co2 Absorption ◽  
Molten Carbonate ◽  
Energy Penalty

The objective of this study is to assess the technical and economic potential of four alternative processes suitable for post-combustion CO2 capture from natural gas-fired power plants. These include: CO2 permeable membranes; molten carbonate fuel cells (MCFCs); pressurized CO2 absorption integrated with a multi-shaft gas turbine and heat recovery steam cycle; and supersonic flow-driven CO2 anti-sublimation and inertial separation. A common technical and economic framework is defined, and the performance and costs of the systems are evaluated based on process simulations and preliminary sizing. A state-of-the-art natural gas combined cycle (NGCC) without CO2 capture is taken as the reference case, whereas the same NGCC designed with CO2 capture (using chemical absorption with aqueous monoethanolamine solvent) is used as a base case. In an additional benchmarking case, the same NGCC is equipped with aqueous piperazine (PZ) CO2 absorption, to assess the techno-economic perspective of an advanced amine solvent. The comparison highlights that a combined cycle integrated with MCFCs looks the most attractive technology, both in terms of energy penalty and economics, i.e., CO2 avoided cost of 49 $/tCO2 avoided, and the specific primary energy consumption per unit of CO2 avoided (SPECCA) equal to 0.31 MJLHV/kgCO2 avoided. The second-best capture technology is PZ scrubbing (SPECCA = 2.73 MJLHV/kgCO2 avoided and cost of CO2 avoided = 68 $/tCO2 avoided), followed by the monoethanolamine (MEA) base case (SPECCA = 3.34 MJLHV/kgCO2 avoided and cost of CO2 avoided = 75 $/tCO2 avoided), and the supersonic flow driven CO2 anti-sublimation and inertial separation system and CO2 permeable membranes. The analysis shows that the integrated MCFC–NGCC systems allow the capture of CO2 with considerable reductions in energy penalty and costs.

scholarly journals Potential of Wind Energy in Albania and Kosovo: Equity Payback and GHG Reduction of Wind Turbine Installation

2015 ◽  
Vol 4 (1) ◽  
pp. 11-19
Author(s):  
Mevlan Qafleshi ◽  
Driton R. Kryeziu ◽  
Lulezime Aliko
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Power Plants ◽  
Combustion Process ◽  
Energy Generation ◽  
Base Case ◽  
Climate Data ◽  
Diesel Generator ◽  
Ghg Reduction ◽  
The Impact

The energy generation in Albania is completely from the hydropower plants. In terms of GHG emissions this is 100% green. In Kosovo 97% of energy is generated from lignite fired power plants. Apart the energy generation, the combustion process emits around 8000 ktCO2/yr and 1.5 Mt of ash in the form of fly and bottom ash. In both countries there is no MWh power generated from wind energy, i.e. this energy source is not utilized. Here, a proposed project for five locations in Albania and Kosovo has been analyzed in detail with the aim of installing a 1kW wind turbine off-grid. The method of study is based on the application of RETScreen International program software. This proposed model is intended to replace a base case- a diesel generator with installed capacity 7kW.  The locations are selected three in Albania: Vlora, Korça and Elbasan, and two in Kosovo: Prishtina and Prizren. All are in different altitudes. By the calculation of RETScreen program, it has been analyzed the feasibility of the proposed projects by installing a wind turbine at hub’s height 20m. The climate data for each location were retrieved by the RETScreen program from NASA. Generally, the calculation of financial parameters for the investments came out to be positive, the impact of GHG reduction very significant. A 5500 USD investment for the implementation of proposed case showed an equity payback time of 2-3 yrs and GHG reduction of 2.2 tCO2/yr. The electricity delivery to load only from this 1 KW wind turbine resulted to be between 1.6-17 MWh/yr.

scholarly journals Composition and Morphology Characteristics of Magnetic Fractions of Coal Fly Ash Wastes Processed in High-Temperature Exposure in Thermal Power Plants

2019 ◽  
Vol 9 (9) ◽  
pp. 1964 ◽  
Author(s):  
Dinh-Hieu Vu ◽  
Hoang-Bac Bui ◽  
Bahareh Kalantar ◽  
Xuan-Nam Bui ◽  
Dinh-An Nguyen ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Combustion Process ◽  
Mineralogical Composition ◽  
Striking Difference ◽  
Thermal Power Plants ◽  
Power Stations ◽  
Magnetic Components

Coal-fired power stations are one of the primary sources of power generation in the world. This will produce considerable amounts of fly ash from these power stations each year. To highlight the potential environmental hazards of these materials, this study is carried out to evaluate the characterization of fly ashes produced in thermal power plants in northern Vietnam. Fly ash was firstly fractionated according to size, and the fractions were characterized. Then, each of these fractions was analyzed with regard to their mineralogical features, morphological and physicochemical properties. The analytical results indicate a striking difference in terms of the characteristics of particles. It was found that magnetic fractions are composed of magnetite hematite and, to a lower rate, mullite, and quartz. Chemical analyses indicate that the non-magnetic components mainly consist of quartz and mullite as their primary mineral phases. As the main conclusion of this research, it is found that the magnetic and non-magnetic components differ in terms of shape, carbon content and mineralogical composition. In addition, it was found that magnetic components can be characterized as more spheroidal components compared to non-magnetic ones. This comprehensive characterization not only offers a certain guideline regarding the uses of different ash fractions but it will also provide valuable information on this common combustion process.

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