The potential for material processing by microwave energy
This paper presents the potential applications for material processing by microwave energy which is electromagnetic waves that penetrates material and cause its molecules to rotate and generate heat. In this paper, potential uses of microwave energy in iron and steel making processes will be discussed in detail. Actually, microwave energy has been in use for various applications for over half century. One of the most well known applications is drying and cooking of food. Currently, industrial uses of microwave energy include direct-reduced iron making, wood processing, sintering, coke making, and so on. And moreover, CO2 and CH4 can be decomposed by super heating effect of microwave energy which can also be called as high temperature plasma furnace. In conventional heating processes, the materialpsilas surface is heated first and then the heat moves inward, while the material is heated the entire volume at about the same time, in microwave heating processes. Microwave heating method can be used in addition to conventional heating techniques to enhance the reaction of the material processing.
Decomposition of Low-Pressure Pollutant by Repeated Pulse Microwave Discharge
Experimental results of the decomposition of CO2 and Freon-12 by repeated pulse microwave discharge in low-pressure gas are presented. With the use of this nonequilibrium plasma, the carbon dioxide was efficiently deoxidized to CO without adding a reducing agent (hydrogen). Optimum efficiency was 275 nmol/J at a pressure of 533 Pa and microwave power of 150 W. Freon-12 was decomposed in ratios of 67% (53.3 Pa) and 35% (133 Pa) by 10 s discharge. Optimum efficiency of 20 nmol/J was obtained at a pressure of 133 Pa. The optimum values should be related to the generation of high-energy electrons which were active in chemical reaction, and the amount of molecules in the reactor chamber. This process can be used as a pretreatment of low-pressure pollutant gas without adding any other gas.
Operating characteristics and commercial operating experience with high temperature SCR NOx catalyst
Selective catalytic reduction of NO x has been recognized as a very effective method to achieve low NO x emissions. A family of versatile catalyst technologies has been developed by Engelhard to control NO x emissions over a wide range of operating temperatures, 177 to 593 o C (350 to 1100 o F). Reaction mechanisms are different for the catalysts used over this broad temperature range. The catalyst designed for high temperature operation is zeolite based and operates in the 454 to 593 o C range (850 to 1100 o F). Performance characteristics of this high temperature SCR NO x catalyst are presented. The reaction mechanism for the high temperature catalyst is contrasted with the low and medium temperature catalyst