用后镁钙砖用于湿法烟气脱硫的试验研究

Research on used magnesia-calcia brick for wet flue gas desulfurization

为了探讨用后镁钙砖应用于火电厂湿法烟气脱硫的可行性,将其加工成不同粒度的细粉,加水配制成不同浓度的脱硫剂浆液,在不同脱硫温度和烟气流量条件下进行湿法脱硫试验,利用正交试验并结合实际情况优选出最佳脱硫条件,并在相同条件下与氧化镁脱硫剂进行了对比试验,同时研究了用后镁钙砖的脱硫效率随脱硫时间的变化。结果表明:1)在用后镁钙砖细粉粒度为≤0.074 mm,脱硫剂浆液中用后镁钙砖细粉的质量分数为10%,脱硫温度为100℃,烟气流量为0.16 L·min-1的条件下,脱硫率达到最高,15 min内的平均脱硫率为99.83%,而相同条件下氧化镁脱硫剂的为99.6%,表明用后镁钙砖可以取代氧化镁应用于湿法烟气脱硫工艺中。2)随着脱硫时间的延长,用后镁钙砖脱硫剂的脱硫率逐渐减小,但在90 min内的平均脱硫率均可达96%,其中,用后镁钙砖细粉质量分数为15%的脱硫剂在15 min内的平均脱硫率高于99.5%,在90 min内的仍接近97.5%。

In order to discuss the feasibility of used magnesia-calcia brick for wet flue gas desulfurization of heat-engine plant,the used magnesia-calcia bricks were processed into fine powders with different particle sizes,and then added with water to make up desulfurizing agent slurries with various concentrations. The wet desulfurization tests were carried out at different temperatures and flue gas flow rates. The optimal desulfurization conditions were selected using orthogonal experiment combining with the actual situation. The contrast experiment using magnesia as desulfurizing agent was also carried out under the same condi- tion. And the relationship of desulfurization efficiency versus time of used magnesia-calcia brick was also researched. The results show that：（1）in the conditions of ≤0.074 mm used magnesia-calcia brick powder,10 mass% slurry concentration, 100℃ desulfurization temperature, and 0. 16 L · min-1 flow rate,the desulfurization efficiency is the highest,the average value is 99.83% within 1.5 min, higher than the 99.6% of the slurry using magnesia desulfurizing agent, meaning the used magnesia-calcia brick can replace magnesia to be used in wet flue gas desulfurization process; （2） Desulfurization efficiency decreases with time prolonging, but the,average values for different concentrations can reach 96% within 90 min, in which for 15% concentration,the average value is 99.5% within 15 min and still close to 97..5% within 90 min.