Effect of K Addition and Acidification of Zeolite Support on the Performance of Zr:Mo/Hzsm-5 Modified Catalyst in Methane Aromatization
The conversion of methane into higher hydrocarbons and aromatics on potassium doped modified zeolite Zr:Mo catalysts under non oxidizing conditions have been studied in a fixed bed catalytic reactor system at 450 0 C and at atmospheric pressure. The potassium addition reduces the formation of carbon during the catalytic reaction. This also results in the stability of the catalyst system and increased aromatics production. This is due to electronically modified active sites and increase in Bronsted acidity.
Conversion of acetylene to benzene over palladium single-crystal surfaces. II. The effect of additives
The conversion of acetylene to benzene over palladium single-crystal surfaces ((111), (100), and (110)) modified with submonolayer quantities of silicon, phosphorus, sulfur, chlorine, and potassium has been studied under both ultrahigh vacuum and atmospheric pressure conditions. At atmospheric pressures electron-donating additives enhance the rate of benzene formation and electron-accepting additives reduce the rate. Potassium and silicon reduce the amount of surface carbon that accumulates during the reaction and thereby increase the rate of benzene formation relative to the undoped surface. The general trends of the (111), (100), and (110) faces indicate that at low pressures potassium suppresses, silicon and phosphorus enhance, and sulfur and chlorine leave unchanged the benzene yield. Silicon on the (100) face showed the greatest enhancement in the benzene yield possibly due to surface compound formation.
Heat Transfer Characteristic for a New Plate Metal Hydride Reactor
The property of major metal hydride reactors in the world was analyzed and a new plate metal hydride reactor was designed.An experimental facility to test the metal hydride reactor was also designed correspondingly.The effective thermal conductivity of the plate metal hydride reactor was measured by varying the initial metal hydride packing fraction,the kind of filled gas and the pressure of the filled gas,cycle numbers.The test results show that the effective thermal conductivity of the reactor,has exceeded(7.5) W/(m·K) before activation,which is increased greatly.After alloy activation,the effective thermal conductivity of the reactor has a linear change trend with the hydrogen pressure during the interval 0.1~3.5 MPa.The effective thermal conductivity of the reactor just only decreases quickly at the beginning,but becomes stable after several cycles.