Fractional factorial study of HCN removal over a 0.5% Pt/Al₂O₃ catalyst: effects of temperature, gas flow rate, and reactant partial pressure
Fractional factorial design was used to determine which factors have significant effects on the HCN (hydrogen cyanide) oxidation reaction over 0.5% Pt/Al?O? under lean conditions. We conclude that the reaction temperature and gas-hourly space velocity (GHSV) have significant effects on the HCN conversion, while no significant effects are caused by the presence of either NO (nitric oxide) or C?H? (propene). A central composite design was used to study the effects of temperature and GHSV on HCN conversion, C?H? conversion and NOx selectivity. Based on a second polynomial equation model, regression analysis was used to study the significance of each variable term and derive equations for each response. Our results show that HCN conversion was significantly affected by temperature (X3), GHSV (X4), a temperature polynomial term (X32), and a temperature and GHSV interaction term (X3X4). HCN conversion decreased with increasing values of GHSV and increased with increasing temperature, up to a transition temperature that depends on the GHSV value. The variables of temperature (X3), GHSV (X4), and the temperature polynomial term (X32) have significant effects on both C?H? conversion and NOx selectivity, but in these two cases the interaction of temperature and GHSV was not significant. Contour plots of HCN conversion, C?H? conversion, and NOx selectivity versus temperature and GHSV were constructed from an analysis of the measured data, and these plots can be utilized to estimate HCN conversion, C?H? conversion, and NOx selectivity over the range of temperatures and GHSV investigated. Optimum catalyst operation is described by high HCN conversion and low NOx selectivity. These results show C and o that the highest HCN conversion was achieved at temperatures above 250 relatively low GHSV values, while low NOx selectivity was best achieved at a C.o temperature of 215
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 877568
- Report Number(s):
- PNNL-SA-40737; IECRED; 6695; VT0401000; TRN: US200608%%489
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 45, Issue 3; ISSN 0888-5885
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CATALYSTS
DESIGN
GAS FLOW
HYDROGEN
OXIDATION
PARTIAL PRESSURE
POLYNOMIALS
PROPYLENE
REGRESSION ANALYSIS
REMOVAL
TRANSITION TEMPERATURE
VELOCITY
Fractional factorial design
central composite design
regression analysis
oxidation
supported Pt catalyst
HCN
C3H6
NO
NOx selectivity
Environmental Molecular Sciences Laboratory