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

Abstract

Ammonia radicals are produced by a dielectric barrier discharge (DBD) in a chamber, called radical injector, which is separate from the chamber that NO gas flows. The radicals are injected into the mixing zone in NO gas flow field to decompose NO gas. The power source for generating the DBD is a one cycle sinusoidal (OCS) waveform so as to easily control the electrical power consumed in the DBD plasma. The fundamental frequency of the OCS power source is 150 kHz. Based on the molar ratio of ammonia particles to NO particles in a unit time, NO removal characteristics were discussed. By increasing the DBD consumed energy, the molar ratio approaches 1 showing the stoichiometric DeNO by NH 2 radicals. A high energy efficiency is found by reducing the consumed energy in the radical injector, where the molar ratio is higher than 1. In this case, the excess ammonia gas without converting into ammonia radicals in the radical injector is directly injected into the reaction zone, and contributes to decompose the NO gas. Oxygen gases with a concentration from 5% to 15% included in the NO gas significantly contribute to decompose NO gases, which brings a decomposition of NO with a low molar ratio.Index Terms-NO removal, dielectric barrier discharge, intermittent discharge, nonthermal plasma.

Influence of voltage rise time on oxidation treatment of NO in simulated exhaust gas by polarity‐reversed pulse discharge

“…With decreasing removal ratio (less than 80%), the energy efficiency of fast polarity reversal becomes higher than that of slower polarity reversal. Recently, Yukimura and colleagues reported that energy efficiency values above 100 g/kWh could be obtained by ammonia radical injection into a plasma [15]. So far as we know, however, no one has reported successful NO removal with a high energy efficiency (over 60 g/kWh) by plasma without any additives, Fig.…”

Removal of Trichloroethylene by Corona Radical Injection

“…NH3, water vapor and hydrogen peroxide (H2O2) vapor are commonly used as radical source in many researches. It was reported [10][11] that radical injection could reduce energy consumption and improve energy efficiency in the removal of NOx by plasma with NH3 injection. When NH3 is used as an additive for DeNOx process, the final byproducts are stable, and are easily collected in the form of powders such as NH4NO3 [12].…”

Application of dielectric barrier discharge in the removal of NO<inf>x</inf> from diesel exhaust

“…NOx must be removed because it leads to the formation of acid rain and photochemical smog and it is related to several adverse effects on human health, mainly in heart and lungs. Nonthermal plasma is proposed as a prominent non-conventional technique, which can simultaneously treat several pollutants at atmospheric pressure; furthermore, the initial investment and operation costs are relatively low [2].…”

“…Experimental and modeling researches focus on the discharge phenomena and reaction kinetics during the plasma remediation of NOx using dielectric barrier discharges (DBDs) [2]. In reality, DBD is a modified corona discharge and the characteristic of a DBD device is the presence of a dielectric barrier layer on at least one of two electrodes.…”