NO_X / SO_X Ozone treatment technology

What is NO_x / SO_x ozone treatment technology?

NO and SO₂ are oxidized, by adding ozone, into highly soluble oxides (NO₂, N₂O₃, N₂O₅, SO₃ etc.) which can be treated by wet scrubbers

Principles of ozone treatment reaction

1. Main scheme

   • NO₂ + O₃ → O₂ + NO₃
   • 2NO₂ + O₃ → N₂O₅ + O₂
   • NO₂+NO₃ → N₂O₅
   • NO + O₃ → NO₂ + O₂
   • 2NO + 3O₃ → N₂O₅ + 3O₂
   • NO is the main component of NO_X in the combustion gas
   • Highly soluble NO₂, N₂O₃and N₂O₅ are produced by the reaction between NO_x and ozone, which are absorbed in to an alkaline solution

2. Reaction rate and solubility

   Scheme		Relative reaction rate
   NO + O3 → NO2 + O2		62780	fast
   2NO2 + O3 → N2O5 + O2		135	little fast
   SO2 + O3 → SO3 + O2		8	slow
   CO + O3 → CO2 + O2		1	very slow
   Substance	NO	NO2	SO2	N2O5
   Solubility(25℃)	0.063	1.26	126	＞126

   • NO_xis rapidly converted into a water-soluble substance because the reaction rate with ozone is very fast compared to other substances
   • Easily adsorbed by washing with water after becoming NO₂, N₂O₅

Process chart

Features

• High temperature not required unlike SCR(300~420℃) and SNCR(850~1,100℃)
• Inexpensive maintenance cost as an expensive catalyst is not required
• No need for a large site because ozone is injected into the existing wet scrubber
• Treatment of various pollutants such as dioxin, carbon monoxide, etc.
• Highly efficient treatment at 80% or higher
• Nearly no secondary pollution
• Possible combination with other treatment methods such as SCR and SNCR
• Interconnected operation depending on the concentration level of pollutants
• Simple operation and easy maintenance because the management is mostly required for ozone generators

Comparison with the conventional treatment method

Actual installation

1. ○○ paper mill : Removal NO_x / SO_x

   • Treatment : 65,000N㎥/h
   • Ozone generation : 14.5㎏/h, 16wt%
   • NO_x treatment efficiency : 90%