Optimum Conditions for NO Reduction Using Intermittent Dielectric Barrier Discharge at Atmospheric Pressure

Abstract

NO in N 2 gas was removed by injecting ammonia radicals, which were externally generated by flowing NH 3 gas diluted with Ar gas through a dielectric barrier discharge (DBD) with a one-cycle sinusoidal-wave power source. The discharge was intermittently formed between coaxial cylindrical electrodes at an applied peak-to-peak voltage of 2-15 kV. The generated radicals were introduced in a reaction chamber and reacted with NO. In order to find optimum parameters for NO reduction and energy efficiency, the reaction temperature in the mixing zone, the voltage applied to the gap of the electrodes for DBD generation and its repetition rate, the NO gas concentration, and the ammonia concentration and flow rate were varied. A maximum energy efficiency of 140 g/kWh at a NO reduction of over 99% is obtained at a voltage slightly higher than the discharge firing voltage and a repetition rate of 5 kHz, which corresponds to a duty cycle of 5%. Thus it is found that the use of the intermittent power source is an advantage for obtaining a high energy efficiency of NO reduction.

Molar ratio and energy efficiency of DeNO/sub x/ using an intermittent DBD ammonia radical injection system

“…Second, NO is removed without oxygen gas in NO gases, and when oxygen gas is included in NO gas, NO removal characteristics are not dependent on the oxygen concentration from 5% through 15%. Third, the present system has a wide temperature range of NO removal [14]. Fourth, the present system is performed by a low power consumption in the plasma.…”

Optimum conditions of low temperature SNCR by hydrogen injection

“…It's desirable to install the SNCR equipment to incinerators, but temperature of the flue gas is around 750 ºC, therefore it is impossible to apply the incinerators. We have been developed an original SNCR using dielectric barrier discharge (2,3) . The advantages of the SNCR system are low temperature reaction.…”

Non-Catalytic deNO_x Using Activated Ammonia Generated by Vacuum Ultra Violet

“…大気圧プラズマ励起と同等の脱硝性能を得られることを確認した (6) VUV 反応器は，内径 80 mm，長さ 105 mm のアルミ製円筒型反応器の中心部に，Xe ガス封入誘電体バリア放電方 式のエキシマランプ(USHIO Inc., 直径 40 mm の円筒型，ランプ出力 26 mW cm− 2 ) )を配置した構造である (6) ．NH 3 ガスは， ランプ表面とカバー内面の隙間 (20 mm) を反応器下部から上部に流れる． ガス流路の容積は 377 cm 3 である．…”