Activated Coke for Desulfurization & Denitrification
From Activated Coke
Activated coke is an excellent adsorbent, which can adsorb the S02 and S03 from industrial boilers' flue gas emissions at the window temperature (120 °C - 180 °C) without heating the flue gas; Meanwhile, activated coke is also a excellent catalyst, it can restore the NOx into N2 and H20 with the conditions of adding the reductant NH3. so the performance of activated coke is the core of flue gas purification effect.
Activated coke's production process & facilities are similar as those for pellet activated carbons, but the specific conditions of the production process, raw material ratio, the main structure of the production equipments have some variations. Principle of activated coke purification technology
Principle of flue gas purification
According to the adsorption characteristics and catalytic properties of activated coke, S02,
02, and water vapor in the flue gas are adsorbed on the surface of activated coke, then the H2S04 is generated through reaction on surface and is adsorbed into the micropore of activated coke, so as to achieve the effect of flue gas desulfurization.
2S02 + 02 + 2H20 -> 2H2S04
The catalytic properties of activated coke is used for selective catalytic reduction (SCR) to denitrate, the NOx is restored to N2 by using NH3 as the reductant 4NO + 4NH3 + 02 — 4N2 + 6H20 2N02 + 4NH3 + 02 — 3N2 + 6H20
Mechanism of activated coke's regeneration
Heat the S02 saturated activated coke to 400 °C -500 °C, the sulfuric acid or sulfate in the
activated coke are decomposed and desorbed, the main decomposition products generated
are S02, N2, C02, H20, the physical form is high concentration of S02 gas, the main
reaction is between activated coke and sulfuric acid:
2H2S04 + C — 2S02 + C02 + 2H20
The activity of activated coke can be restored after regeneration, after regeneration, the adsorption and catalytic ability of activated coke not only do not reduce, but will be improved, but after several times of regenerations, those properties will decrease