高炉煤气精脱硫技术的半工业试验

 高炉煤气中有机硫(主要是COS)含量高,无机硫含量低,硫的脱除难度大。针对以上特点,在山东某金属公司进行了干法精脱硫工艺的半工业试验。具体的工艺方案为,脱硫设备布置在高炉TRT设备之后,高炉煤气通过旁通管从高炉煤气管网上接入脱硫试验装置。水解和脱硫反应器均为填充床形式,采用“一级水解+脱硫”串联“二级水解+脱硫”的两级串联设计方案。在相应的水解和脱硫反应器中分别填充一种改进型的Al₂O₃基低温水解催化剂和氧化铁基脱硫剂。水解催化剂促使煤气中的有机硫(COS)与水蒸气反应生成H₂S,再由脱硫剂与H₂S反应生成Fe₂S₃,从而实现煤气中硫的脱除。在半工业试验中,进入脱硫设备的煤气流量为400 m3/h,煤气温度为80~100 ℃,COS的体积分数约为70%,H₂S的体积分数约为25%,煤气中硫浓度为145 mg/m3。经过300 h的连续试验,结果表明,该脱硫工艺全过程废水零排放;高炉煤气中有机硫(COS)转化为无机硫(H₂S)的转化率约为99%;煤气中硫分的脱除率大于96%;能够保证煤气燃烧后烟气中SO₂浓度小于10 mg/m3。

Pilot plant test of BF gas deep desulfurization technology

In BF gas, the content of organic sulfur, which is mainly COS, is high while the content of inorganic sulfur is comparatively low, so that BF gas is difficult to desulfurize. Aimed at above difficulty, a BF gas deep desulfurization process, a dry process before gas combustion, was developed and tested in pilot plant scale at a metal company in Shandong province. The process scheme was as follows. The desulfurization test equipment was mounted at downstream direction of the blast furnace TRT module, and BF gas was connected to the desulfurization test equipment from the blast furnace′s gas pipe line through the bypass. The hydrolysis and desulfurization reactors were both packed beds, and designed as two-stage series connected type, which were "primary hydrolysis + desulfurization" and "secondary hydrolysis + desulfurization" modules. The hydrolysis and desulfurization reactors were filled with an improved Al₂O₃ based low-temperature hydrolysis catalyst and ferric oxide based desulfurizer, respectively. The hydrolysis catalyst promoted the reaction of COS with water vapor to produce H₂S in BF gas, and then the desulfurizer reacted with H₂S to produce Fe₂S₃. Thus, sulfur was removed from BF gas. In the pilot plant test, the gas flow rate was 400 m3/h, the gas temperature was about 80-100 ℃, the volume percent of COS and H₂S were about 70% and 25%, respectively, and the total sulfur content of BF gas was 145 mg/m3. After more than 300 h of continuous running, pilot tests show that after processing, there is no waste water discharged, the converting rate of COS into H₂S is about 99%, desulfurization rate is more than 96%, and the density of sulfur dioxide in exhausted gas (after combustion) is less than 10 mg/m3.