La-Ce-Y-W Cathodes Application for High Temperature Electrostatic Precipitator

2010 ◽  
Vol 113-116 ◽  
pp. 437-441 ◽  
Author(s):  
Zhong Zhu Gu ◽  
Jian Can Yang ◽  
Xiao Li Xi ◽  
Zuo Ren Nie ◽  
Jin Jin Xu
Keyword(s):  
Electron Emission ◽  
Flue Gas ◽  
Electrostatic Precipitator ◽  
Average Diameter ◽  
Dust Particles ◽  
Effective Work ◽  
Effective Work Function ◽  
Positive Effects ◽  
Precipitation Efficiency ◽  
Microstructure Of The Material

La-Y-Ce-W cathode was prepared by powder metallurgy. XRD, OM, SEM and EDS were applied to analyze the microstructure of the material. La, Ce and Y concentrate on the tungstate particles and exist as Rare Earth (RE) tungstate. The average diameter of the particles is about 30µm. The electron emission properties were measured with self-designed electron emitter surveyor. Its effective work function was 2.76eV at 1300°C. The precipitation efficiency of an electrostatic precipitator (ESP) installed with the cathode was investigated in a certain flue gas condition. It was found that it can trap over 95% dust particles with diameter bigger than 1µm. As to dust particles with diameter smaller than 0.1µm, the efficiency is lower than 85%. Increasing collection voltages showed greater positive effects on the precipitation efficiency of smaller particles than that of larger particles.

A New Carbon Nanotube-Based Field Enhanced Thermionic Cathode

2004 ◽  
Vol 858 ◽  
Author(s):  
Feng Jin ◽  
Christopher Day
Keyword(s):  
Electron Emission ◽  
Field Enhancement ◽  
Oxide Coating ◽  
Enhancement Effect ◽  
High Electron ◽  
Thermionic Cathode ◽  
Emission Properties ◽  
Effective Work ◽  
Effective Work Function ◽  
Thermionic Cathodes

ABSTRACTThe electron emission properties and field enhancement effects of carbon nanotubes (CNTs) have been extensively studied. However, all of these studies focus only on the field emission aspect of the materials and its application in cold cathode electron emitters. So far, we have not seen any studies in the literature that link CNTs with thermionic cathodes, which are an equally important cathode type because of their many applications. We present a study of field enhanced electron emissions from a new type of cathode: the CNT-based field enhanced thermionic cathode. This new cathode consists of a metal substrate with CNTs grown on top of its surface. The CNTs are coated with thermionic emission materials (BaO, SrO, and CaO). This unique cathode structure takes advantage of both the field enhancement effect from CNTs and the high electron emission capability of thermionic materials. The electron emission properties of this new cathode, particularly the field enhancement factor and effective work function, are compared with the conventional thermionic cathodes that are made of same oxide coating.

Mo and Co Silicide FEAs

2000 ◽  
Vol 621 ◽  
Author(s):  
Jong Duk Lee ◽  
Byung Chang Shim ◽  
Sung Hun Jin ◽  
Byung-Gook Park
Keyword(s):  
Single Crystal ◽  
Electron Emission ◽  
Single Crystal Silicon ◽  
Anode Current ◽  
Crystal Silicon ◽  
Vacuum Level ◽  
Effective Work ◽  
Effective Work Function ◽  
Field Emitters ◽  
Tip Radius

ABSTRACTFor enhancement and stabilization of electron emission, Mo and Co silicides were formed from Mo mono-layer and Ti/Co bi-layers on single crystal silicon FEAs, respectively. Using the slope of Fowler-Nordheim curve and tip radius measured from SEM, the effective work function of Mo and Co silicide FEAs are calculated to be 3.13 eV and 2.56 eV, respectively. Compared with silicon field emitters, Mo and Co silicide exhibited 10 and 34 times higher maximum emission current, 10 V and 46 V higher failure voltage, and 6.1 and 4.8 times lower current fluctuation, respectively. Moreover, the emission currents of the silicide FEAs depending on vacuum level are almost same in the range of 10−9 ∼ 10−6 torr. This result shows that silicide is robust in terms of anode current degradation due to the absorption of air molecules.

Experiments on the Removal of Fine Particles in Existing Air Pollution Control Devices by Chemical Agglomeration

2014 ◽  
Vol 1010-1012 ◽  
pp. 756-760 ◽  
Author(s):  
Yong Liu ◽  
Lin Jun Yang ◽  
Dan Ping Pan ◽  
Rong Ting Huang
Keyword(s):  
Flue Gas ◽  
Pollution Control ◽  
Fine Particles ◽  
Electrostatic Precipitator ◽  
Average Diameter ◽  
Flue Gas Desulfurization ◽  
Air Pollution Control ◽  
Control Devices ◽  
Air Pollution Control Devices ◽  
Wetting Liquid

The removals of PM2.5from coal combustion by electrostatic precipitator (ESP) and wet flue gas desulfurization (WFGD) system with adding chemical agglomeration solution were investigated experimentally based on coal-fired thermal system. The experimental results show that the average diameter of particles could grow more than four times with the effect of wetting, liquid bridge force and adsorption bridging, and the PM2.5concentration of ESP outlet can decrease 40% under typical flue gas conditions. The removal efficiency of fine PM2.5is improved about 30% when adding chemical agglomeration solution before desulfurization tower.

Field emission of electrons in discharges

1953 ◽  
Vol 216 (1125) ◽  
pp. 267-279 ◽  
Keyword(s):  
Work Function ◽  
Electric Fields ◽  
Electron Emission ◽  
Rapid Assessment ◽  
Surface Films ◽  
Effective Work ◽  
Effective Work Function ◽  
Electron Production ◽  
Field Emission Of Electrons ◽  
And Tungsten

Substantial emission of 10 4 to 10 5 electrons/s was obtained from cathodes of oxidized nickel and tungsten with electric fields of about 10 5 V/cm. By relating this emission to the electric field by the Fowler-Nordheim equation, estimates of the work function and emitting area of the source of the electrons were made. It was found that the effective work function for the emitting source on oxidized nickel and tungsten was roughly 0.5 eV, and that the emitting areas were 10 -12 cm 2 . This is consistent with the view that the electrons were obtained from the oxide itself and not from the underlying metal. The presence of tarnish films and oxides on electrodes enhanced the cold electron emission greatly, and played an important part in the mechanism of electron production; the presence of metallic dust was found to enhance the emission by factors up to 10 3 . The technique used in the investigation provides a method by which a rapid assessment of the electron emissive properties of metals can be made, and is applicable to a wide variety of surfaces. While a consistent theory of the action of heavily oxidized tungsten and nickel electrodes (surface conditions often met with in practice) can be given, a further experimental investigation of the electron emission from surfaces covered with thin surface films (10 -7 cm) is necessary.

Numerical simulation and field test study of desulfurization wastewater evaporation treatment through flue gas

2014 ◽  
Vol 70 (7) ◽  
pp. 1285-1291 ◽  
Author(s):  
Jia-jia Deng ◽  
Liang-ming Pan ◽  
De-qi Chen ◽  
Yu-quan Dong ◽  
Cheng-mu Wang ◽  
...  
Keyword(s):  
Field Test ◽  
Flue Gas ◽  
Cfd Simulation ◽  
Electrostatic Precipitator ◽  
Negative Impact ◽  
Positive Impact ◽  
Field Tests ◽  
Gas Temperature ◽  
Simulation Results ◽  
Desulfurization Wastewater

Aimed at cost saving and pollution reduction, a novel desulfurization wastewater evaporation treatment system (DWETS) for handling wet flue gas desulfurization (WFGD) wastewater of a coal-fired power plant was studied. The system's advantages include simple process, and less investment and space. The feasibility of this system has been proven and the appropriate position and number of nozzles, the spray droplet size and flue gas temperature limitation have been obtained by computational fluid dynamics (CFD) simulation. The simulation results show that a longer duct, smaller diameter and higher flue gas temperature could help to increase the evaporation rate. The optimal DWETS design of Shangdu plant is 100 μm droplet sprayed by two nozzles located at the long duct when the flue gas temperature is 130 °C. Field tests were carried out based on the simulation results. The effects of running DWETS on the downstream devices have been studied. The results show that DWETS has a positive impact on ash removal efficiency and does not have any negative impact on the electrostatic precipitator (ESP), flue gas heat exchanger and WFGD. The pH values of the slurry of WFGD slightly increase when the DWETS is running. The simulation and field test of the DWETS show that it is a feasible future technology for desulfurization wastewater treatment.

Effective Work-Function Modulation by Aluminum-Ion Implantation for Metal-Gate Technology $(\hbox{Poly-Si/TiN/SiO}_{2})$

2007 ◽  
Vol 28 (12) ◽  
pp. 1089-1091 ◽  
Author(s):  
R. Singanamalla ◽  
H. Y. Yu ◽  
B. Van Daele ◽  
S. Kubicek ◽  
K. De Meyer
Keyword(s):  
Ion Implantation ◽  
Work Function ◽  
Metal Gate ◽  
Effective Work ◽  
Effective Work Function ◽  
Aluminum Ion

Investigating doping effects on high-κ metal gate stack for effective work function engineering

2013 ◽  
Vol 88 ◽  
pp. 21-26 ◽  
Author(s):  
C. Leroux ◽  
S. Baudot ◽  
M. Charbonnier ◽  
A. Van Der Geest ◽  
P. Caubet ◽  
...  
Keyword(s):  
Work Function ◽  
Metal Gate ◽  
Gate Stack ◽  
Effective Work ◽  
Effective Work Function ◽  
Doping Effects

scholarly journals Cyanobacterial Potential for Restoration of Loess Surfaces through Artificially Induced Biocrusts

2020 ◽  
Vol 11 (1) ◽  
pp. 66
Author(s):  
Tamara Palanački Malešević ◽  
Tamara Dulić ◽  
Igor Obreht ◽  
Zorana Trivunović ◽  
Rastko Marković ◽  
...  
Keyword(s):  
Vascular Plant ◽  
Water Systems ◽  
Dust Particles ◽  
Wind Speeds ◽  
Positive Effects ◽  
Loess Particles ◽  
Combating Desertification ◽  
Aeolian Sediment ◽  
Loess Sediment ◽  
Highly Porous

Loess is a highly porous and easily erosive aeolian sediment covering approximately 10% of the Earth’s surface. The weak vegetation cover and high wind speeds in many of these regions make loess sediment the main source of dust in the atmosphere. Dust particles deteriorate air quality and affect soils, crops, water systems, and animal and human health. The commonly used method for combating desertification is revegetation. However, planting various vascular plant species in loess landscapes did not show any long-lasting positive effects. This study aims to assess the potential of cyanobacterial strains for the restoration of exposed loess surfaces through the assisted development of biological loess crusts (BLCs). Isolated cyanobacterial loess strains were screened for the traits (toxicity, biomass and polysaccharide production) desirable for their use in restoration purposes. By simulating semi-arid environmental conditions in specially designed chambers, the potential of cyanobacterial loess strains for assisted development of BLCs and the mechanisms of loess stabilization have been evaluated by chlorophyll a accumulation and microscopic examination. It was confirmed that cyanobacteria have the ability to interact with loess particles resulting in BLC formation, which keeps the particles immobilized and the sediment below the particles stabilized.

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