Highly Effective Oxidation-absorption Pilot Experiments And Simulation Optimization Of Integrated Desulfurization And Denitrification For Coking Flue Gas

Coke oven flue gas contains a large amount of SO₂ and NO_x, and the concentration of emission shows a periodic change. There is research on simultaneous desulfuration and denitration technology in this paper, recent studies show that oxidation- absorption is one of the most effective ways to simultaneously desulfuration and denitration. Oxidant, catalyst and process conditions are the key factors to efficient integration of desulfurization and denitrationThe research selects 2000 m³/h?180 oC? coke oven flue gas as the pilot test raw gas and designs oxidation-absorption desulfurization denitration integration technology, according to the characteristics of the coke oven gas. O3 and H2O2 are chosen as oxidant of denitrification, the ammonia absorbent, during which process using self-made catalyst to improve oxidation efficiency. NO is oxidized in two stages: in the first stage, the majority of NO are oxidized by ozone, the remaining NO in the second step is oxidized by hydrogen peroxide, oxidation products go to the absorption tower with flue gas. Higher oxidation state of NO_x and SO₂ are absorbed together by absorption liquid in the absorber.Pilot test finds that the removal efficiency of sulfur dioxide reaches 98% and there is no significant changes appear in nitrogen oxides when the ammonia concentration is 1 wt% and the liquid-gas ratio 5 L/m³. In the ozone oxidation of denitration experiment, it finds that the nitrogen removal efficiency reaches 94% providing the Ozone injection mole flow reaches 0.8 of nitrogen oxide in flue gas mole flow rate. As increasing the dosage of ozone, nitrogen removal rate changes slightly. When using laboratory catalyst, ozone reacts with gaseous water and as a result generate hydroxyl radicals on the catalyst. Since the O3/NO?mol: mol? equals 0.7, the denitration removal efficiency reaches above 85%. In the hydrogen peroxide oxidation denitration process, temperature exerts a large impact on hydrogen peroxide oxidation denitration, because of which gaseous hydrogen peroxide has higher denitration efficiency compared with liquid hydrogen peroxide. When H2O2: NO?mol: mol? = 1.5:1, the nitrogen removal efficiency reaches up to 31.4%.100000 Nm³/h gas oxidation process is simulated by Aspen Plus simulation software, The calculation respectively explores the flue gas temperature and dosage of oxidant on the influence of the removal efficiency of nitric oxide, which provides a powerful data support for the engineering application.