scholarly journals Simultaneous Visualization of Water Droplets and Oxygen Partial Pressure in Gas-Flow Channels in a Running PEFC

2011 ◽  
Vol 31 (123) ◽  
pp. 149-154
Author(s):  
Junji INUKAI ◽  
Masahiro WATANABE
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Gas Flow ◽  
Water Droplets ◽  
Flow Channels ◽  
Simultaneous Visualization

Degradation of Silicon Carbide in Combustion Gas Flow at High-Temperature and Speed

2000 ◽  
Author(s):  
I. Yuri ◽  
T. Hisamatsu ◽  
Y. Etori ◽  
T. Yamamoto
Keyword(s):  
Silicon Carbide ◽  
Weight Loss ◽  
Water Vapor ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Flow Rate ◽  
Gas Flow ◽  
Gas Flow Rate ◽  
Vapor Partial Pressure ◽  
Water Vapor Partial Pressure

Effects of various basic factors of combustion gas flow conditions on degradation behaviors of silicon carbide have been experimentally determined. The exposure tests were performed for widely varied experimental parameters of the gas temperatures (T = 900–1500°C), pressure (P = 0.3–0.8MPa), gas flow rate (V = 50–250m/s), water vapor partial pressure (PH2O = 32–82kPa) and oxygen partial pressure (PO2 = 24–44kPa). Degradation behaviors of silicon carbide were expressed as the weight loss of the substrate. The weight loss rate depends on the water vapor partial pressure remarkably. The effect of the oxygen partial pressure on the weight loss was smaller than that of the water vapor partial pressure, and the weight loss decreased with the increase of the oxygen partial pressure. Considering the effects of partial pressures of oxygen and water vapor, the gas temperature and the pressure didn’t have much effect on the weight loss. The weight loss depends on the gas flow rate, the increase rate of the weight loss for the gas flow rate becomes small with the gas flow rate. Consequently, the water vapor partial pressure, the oxygen partial pressure, the gas temperature, the pressure and the gas flow rate dependence of the weight loss rate is expressed as PH2O1.9 V0.6 P0.3 / PO20.6.

Oxidation and Evaporation Behaviors of Cr, Cu and As During Incineration of Wood Treated by Chromated Copper Arsenate Preservative

2012 ◽  
Vol 31 (4-5) ◽  
pp. 559-568 ◽  
Author(s):  
Takahiko Matsumoto ◽  
Hiroyuki Matsuura ◽  
Fumitaka Tsukihashi
Keyword(s):  
Heavy Metals ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Gas Flow ◽  
Bottom Ash ◽  
Xrd Analysis ◽  
Chromated Copper Arsenate ◽  
Powder Xrd Analysis ◽  
Almost All ◽  
Copper Arsenate

AbstractWoody materials treated by chromated copper arsenate (CCA) preservative containing copper, chromium and arsenic had been widely used, and thus it is anticipated that a lot of wood waste treated by CCA will be generated as the industrial waste in the future. The environmental pollution by the released heavy metals becomes a serious problem when the wood treated by CCA was incinerated inadequately. There needs the investigation for the behaviors of heavy metals during incineration of wood treated by CCA.The wood sample treated by CCA was incinerated at temperature range between 873 and 1673 K with the oxygen partial pressure between 0.21 and 0.40 atm completely. The proportion of evaporated arsenic increased with increasing temperature and most of arsenic evaporated at about 1600 K. It was suggested that arsenic evaporated as As2O3 or As4O6 during the incineration. On the other hand, most of copper and chromium remained in the bottom ash. The evaporation behaviors of arsenic largely depended on the incineration temperature, while the effects of the oxygen partial pressure of inlet gas and gas flow rate on those were small. Powder XRD analysis of bottom ash revealed that copper and chromium existed as CuCr2O4 and CuCrO2. CuCr2O4 was mainly contained in the bottom ash incinerated at temperature below 1273 K, whereas the ratio of CuCrO2 increased with increasing incineration temperature above 1273 K. Therefore, most of copper and chromium were bivalent and trivalent, respectively, in the bottom ash, and some copper was converted to a monovalent over 1273 K. Almost all arsenic was contained as pentavalent Cu3(AsO4)2, and arsenic was not identified in bottom ash incinerated at temperature above 1273 K.

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