No.066 ; Dry Ammonia Contact Reduction Method Flue Gas Denitration Equipment ( for Coal burning boiler )

No. 066

Classification of Technology:: Air Pollution Control
Type of Industry:: Others
Subject:: Dry Ammonia Contact Reduction Method Flue Gas Denitration Equipment ( for Coal burning boiler )

1. Purpose
Reduction of NOx in boiler exhaust gas.

2. Details and the Time of Introduction
The dry ammonia contact reduction method suitable for large capacity exhaust gas treatment and multiple fuel exhaust gas treatment such as gas, coal and heavy oil was introduced as a flue gas denigration measures when installing coal burning thermal power station. ( Operation April, 1990 )

3. Principle and Structure
(1) Mechanism of denigration reaction
1) Ammonia is injected in the exhaust gas of comparatively high temperature ( 200-400°C ) as a reducing agent and the nitrogen oxides are decomposed into nitrogen and steam in the presence of the catalyst.
2) Reaction formula : 4NO + 4NH₃ + O₂ -> 4N₂ + 6H₂O
(2) Structure of the flue gas denigration equipment
1) Reactor
– Gas longitudinal flow fixed bed type ( prevention of dust blocking on the catalyst layer ).
– Exhaust gas rectifying layer ( dummy layer ) and multihole grid was installed on the catalyst ( reducing wear of the catalyst ).
2) Denigration catalyst
– Titanium oxide solids ( high durability, wear resistance and high SOx resistance ).
– 7 mm pitch lattice shaped catalyst.
– Low SO₂ oxidation catalyst.

4. Effect and Achievement
Denigration : ( Inlet ) 150 ~ 200 ppm -> ( Outlet ) Under 45 ppm ( Average 30 ppm )

Implementing company:: Nippon Steel Corporation yard, Tokai Co-operative Power Company Inc.

Chart