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Show CH + NO = HCN + 0 (1) HCN + OH = NH2 + CO (2) NH2 + NO = N2 + H20 (3) Based on these results a development program was initiated to develop and ultimately commercialize the PYRONOx technology. The development project focused on several aspects of the process including: -Development of a low cost, high reliability plasma torch, -Optimization of the performance using natural gas, -Identifying the optimum operating stoichiometries and temperatures, -Identifying any byproducts of the process, -Optimizing the mixing of the plasma and flue gases, -Development of kinetic models suitable for the PYRONOx chemistry. The overall objective of the project was to develop the PYRONOx technology in a NOx control process having the potential for high NOx reductions at a lower capital and operating cost than competing systems. An overall schematic of a conceptional design for a PYRONOx boiler installation is shown in figure 2. The system would include the plasma torch, power supply, control panel and a mixing enhancer to accelerate the mixing between the plasma and flue gases. EXPE~NTALSYSTEMS Plasma Torch Several type plasma torch systems were considered for use in the PYRONOx process. Microwave, RF and DC systems were all evaluated based on both technical and economic considerations. Based on technical criteria both the microwave and RF systems are probably superior to the DC systems for generating the plasma modified gases since electrodes are not necessary and more uniform heating of the gas mixture compared to a DC torch is obtained. The disadvantages for both the microwave and RF systems is the price of the power supply, which particularly for high powered systems is considerably greater than for a DC system (for example the cost of a power supply for a 50 KW DC power supply is about $5,000 while the cost for a 50 KW RF power supply is about $50,000). Consequently, because of the significantly lower cost, the DC type plasma torch was chosen as the best available design for the PYRONOx development project. The design of the DC type torch is in principal relatively simple. An electric arc is struck between an anode and cathode. The plasma gas is then passed through the arc creating a high temperature plasma. In order to create uniform heating of the gas, the arc can either be rotated magnetically or a high swirl can be imparted to the plasma gas and the arc kept stationary. The power supply used for the torch is a simple DC power supply similar the type used for arc welding. The specific torch gesign for the PYRONOx project is shown in figure 3. The torch is 3 |