焦炉烟气湿法钢渣联合脱硫脱硝工艺及机理研究

Research on technical method and mechanism of combined desulfurization and denitrification of flue gas from coking furnace with steel slag

富含氧化钙和氧化镁的废钢渣有望成为低成本硫和氮氧化物的碱性吸收剂而用于废气的净化。本文测试和分析了首钢转炉钢渣的成分,将其制成钢渣浆料用于焦炉烟气的联合脱硫脱硝;设计和制作了鼓泡反应装置;研究了湿法钢渣浆料脱除NO和SO_2的工艺和机理,并采用HSC Chemistry 6.0软件对相关反应做了热力学分析。结果表明,钢渣中碱性物质具有脱硫和脱硝作用;此时在反应器内的气-液-固三相体系中发生的化学脱除反应,大部分为自发放热反应;在303.15 K时,固含量8%的钢渣浆液对焦炉烟气的SO_2的脱除率可达97%,NO的脱除率却仅为10.1%,温度升高,SO_2和NO的脱除率下降。为了进一步解决其中NO脱除率低的问题,设计将氧气配入到烟气中,氧化NO成易于被浆料吸收和转化的氮氧化物,并同时在浆料中添加高锰酸钾做氧化助剂。结果表明,它们的存在使脱硝率得到了大幅提高,当O_2体积浓度为5%,高锰酸钾质量分数为2%时,SO_2和NO的总脱除率分别达到了98%和96%,使焦炉烟气的联合脱硫脱硝的应用成为可能,从而为钢渣脱硫和脱硝的理论研究及实际应用奠定了良好基础。

Scrap steel slag rich in calcium oxide and magnesium oxide is expected to become a low-cost alkaline absorber of sulfur dioxide and nitrogen oxides for the purification of exhaust gas.In this paper, the composition of steel slag from Shougang Company for the slag slurry was ana!yzed.A kind of bubbling reactor with the slurry for the removal of NO and SO2 was designed and manufac- tured, and the corresponding reaction thermodynamic was analyzed with HSC chemistry 6.0 software.Alkaline substances in the steel slag played an effective role in desulfurization and denitration of flue gas and the chemical reactions among them in the gas-liquid- solid three-phase system in the reactor were spontaneously exothermic.Thc results showed that the slag slurry with 8% solid content had high desulfurization rate of 97% and denitration rate of 10.1% for the coke oven flue gas at 303.15 K, and the removal rates of SO2 and NO decreased with increasing temperature.For resolving the problem of low NO removal effect further, oxygen was mixed in the flue gas to covert NO into the substances easily absorbed in the slurry, and KMO4 was added as assistant oxidant in the slurry. The results exhibited that the presence of them significantly improved the effect of the removal of NO, and the overall removal rates of SO2 and NO under 5% （ volume concentration） O2 and 2% （ mass fraction） KMO4 were 98% and 96%, respectively, and this might be benefit theoretically and practically for the desulfurization and denitrification of coke oven flue gas by steel slag in the fu- ture.