Wyniki wyszukiwania - Biblioteka Nauki

1

Hydrogen production from ethanol in nitrogen microwave plasma at atmospheric pressure

100%

Hrycak B. , Czylkowski D. , Miotk R. , Dors M. , Jasinski M. , Mizeraczyk J.

Open Chemistry

|

2015

|

tom 13

|

nr 1

EN

Hydrogen seems to be one of the most promising alternative energy sources. It is a renewable fuel as it could be produced from e.g. waste or bio-ethanol. Furthermore hydrogen is compatible with fuel cells and is environmentally clean. In contrast to conventional methods of hydrogen production such as water electrolysis or coal gasification we propose a method based on atmospheric pressure microwave plasma. In this paper we present results of the experimental investigations of hydrogen production from ethanol in the atmospheric pressure plasma generated in waveguide-supplied cylindrical type nozzleless microwave (2.45 GHz) plasma source (MPS). Nitrogen was used as a working gas. All experimental tests were performed with the nitrogen flow rate Q ranged from 1500 to 3900 NL h-1 and absorbed microwave power PA up to 5 kW. Ethanol was introduced into the plasma using the induction heating vaporizer. The process resulted in an ethanol conversion rate greater than 99%. The hydrogen production rate was up to 728 NL[H2] h-1 and the energy efficiency was 178 NL[H2] per kWh of absorbed microwave energy.

2

Study of low temperature inactivation of spores using microwave excited air plasma

86%

Nagatsu M. , Singh M. K. , Zhao Y. , Fujioka Y. , Ogino A.

|

2009

|

tom Vol. 3, No. 4

108-111

EN

In the present study, we investigated the inactivation characteristics and contribution of different inactivating factors generated in a low temperature and low pressure nitrogen, oxygen and air-simulated plasma for the inactivation of Geobacillus stearothermophilus spores. We used three optical filters i.e. thin quartz (lambda>180 nm), lithium fluorine (LiF, lambda>120 nm) and Pyrex glass (lambda>300 nm) plates to identify the most efficient wavelength range. The effect of optical radiations alone was studied through placing a small isolated and evacuated chamber with spore sample inside the plasma chamber.

3

Production of hydrogen via methane conversion using microwave plasma source with CO2 or CH4 swirl

86%

Jasiński M. , Dors M. , Mizerczyk J.

|

2009

|

tom R. 85, nr 5

124-126

EN

In this paper, results of hydrogen production via methane conversion in the atmospheric pressure microwave plasma with CO2 or CH4 swirl are presented. A waveguide-based nozzleless cylinder-type microwave plasma source (MPS) with gas swirl was used to convert methane into hydrogen. The plasma generation was stabilized by a gas swirl having a flow rate of 50 l/min (when CO2 was used) or 87.5 l/min (when CH4 was used). The methane flow rate was 175 l/min or 87.5 l/min. The absorbed microwave power was varied in the range 1500-5000 W. The methane conversion degree and the energetic hydrogen mass yield were highest when methane was used as swirl and was 99.88% and 577 g [H2] per kWh of microwave energy absorbed by the plasma, respectively. These parameters are better than our previous results when nitrogen was used as a swirl gas and much better than those typical for other plasma methods of hydrogen production (electron beam, gliding arc, plasmatron).

PL

W artykule przedstawiono wyniki produkcji wodoru w procesie konwersji metanu pod wpływem plazmy mikrofalowej pod ciśnieniem atmosferycznym w atmosferze CO2 lub w czystym metanie. Do badań wykorzystano generator o konstrukcji współosiowej z dodatkiem lub bez CO2 w formie przepływu wirowego (50 l/min), który stabilizował plazmę. Natężenie przepływu metanu wynosiło 175 l/min lub 87,5 l/min. Absorbowana moc mikrofal wynosiła 1500-5000 W. Uzyskany stopień konwersji metanu oraz wydajność energetyczna produkcji wodoru wynosiły odpowiednio 99,88% i 577 g[H2]/kWh. Wyniki te są lepsze od uzyskanych z zastosowaniem azotu w przepływie wirowym oraz innymi metodami plazmowymi (plazmotron, ślizgające się wyładowanie łukowe, strumień elektronów).

4

Coaxial microplasma source

86%

Kroplewski Ł. , Jasiński M. , Dors M. , Zakrzewski Z. , Mizerczyk J.

|

2009

|

tom R. 85, nr 5

118-121

EN

In this paper the results of an experimental investigation of a microwave sustained discharge in argon at atmospheric pressure are given. The coaxial based plasma torch operated at frequency of 2.45 GHz for gas flow rates of 0.7, 1.5 and 3 l/min. Measurements of the absorbed versus reflected power as well as the electromagnetic field and the anti-bacteria UVB radiation close to the discharge were conducted. Results of measurements show that our simple microwave microplasma source (MMS) operate stable in relatively large range of power and gas flow rate. UVB emitted by the MMS may be used for materials disinfection.

5

Obwód zastępczy kolumny plazmy w falowodzie prostokątnym: wpływ koncentracji elektronów i średnicy kolumny plazmy

72%

Nowakowska H. , Dębicki P. , Mizeralczyk J.

|

2010

|

tom R. 86, nr 11a

275-278

PL

W celu wyznaczenia obwodu zastępczego kolumny plazmy umieszczonej wewnątrz falowodu prostokątnego równolegle do jego krótszej ścianki obliczono numerycznie dwuwymiarowe rozkłady pola elektrycznego oraz elementy macierzy rozproszenia i macierzy impedancji czwórnika reprezentującego ten falowód. Odwód zastępczy przedstawiono jako układ impedancji typu T i zbadano wpływ koncentracji i częstości zderzeń elektronów oraz średnicy plazmy na jego elementy. Określono warunki, w jakich nie można pomijać impedancji szeregowej układu.

EN

To find equivalent circuit of an uniform plasma column placed in a rectangular waveguide parallel to its wider wall, 2D electric field distributions have been numerically calculated and scattering as well as impedance matrix elements of a two-port network representing this waveguide determined. A T-type equivalent circuit have been proposed and influence of the plasma diameter, electron density and collision frequency and on its elements have been examined. Conditions for which the shunt impedance cannot be neglected have been determined.

6

Optoelektroniczny system przestrzennego monitoringu wzbudzenia plazmy w procesach syntezy optycznych warstw diamentopodobnych

72%

Bogdanowicz R.

|

2010

|

tom Vol. 51, nr 1

45-47

PL

Przedmiotem pracy jest optoelektroniczny system do badania wzbudzenia plazmy mikrofalowej w procesie syntezy warstw DLC (ang. Diamond Like-Carbon). W komunikacie zaprezentowano budowę systemu do przestrzennego monitoringu stanu wzbudzenia plazmy podczas procesu CVD. System SR-OES (ang. Spatially Resolved Optical Emission Spectroscopy) umożliwia określanie rozkładu wzbudzenia cząstek w przestrzeni komory i na tej podstawie wybrania optymalnego położenia podłoża oraz prądów cewek ECR.

EN

The main topic of article is optoelectronic system dedicated for plasma diagnostics during DLC layer synthesis. The setup of spatially resolved plasma excitation monitoring system is presented in this paper. SR-OES system enables investigations of distributions of species excitations in the area of chamber, what leads to optimal selection of substrate holder position and ECR coils configuration. The SR - OES monitoring results shows high concentrations of ionized species and non-linear progress of excitation and ionization reactions. It proves the previously obtained molecular modeling.