【作者】 曹媛；

【导师】 王娟； 钟秦；

【作者基本信息】 南京理工大学 ， 化学工程与技术， 2012， 硕士

【摘要】 碱吸收-微生物烟气脱硫技术以钠碱溶液吸收烟气中的SO2形成SO32-/SO42-,再利用厌氧微生物还原SO32-/SO42-形成S2-,最后采用好氧微生物氧化S2-生成单质硫(SO),实现硫资源的回收利用。论文着重研究钠碱吸收-生物脱硫工艺中的生物过程,以模拟SO2碱吸收液为处理对象,考察了好氧反应器的启动与运行,厌氧与好氧反应器的串联和运行,以及单质硫产品的表征。在容积为45L的内循环生物流化床好氧反应器内,利用无色硫细菌将模拟废水中的S2-氧化为S0。在流化床内温度30±2℃、pH值7.50+0.50及进水pH值7.00～7.50、COD：N：P=100：5：1的条件下启动并运行反应器。28d后,反应器内形成大量微生物体,当有机物和S2-负荷稳定在3.73kgCOD·m-3·d-1和1.09kgS2-.m-3·d-1时,相应的脱除率维持在78%和90%以上,理论S0产率为75%左右。考察了水力停留时间(HRT)和曝气量对反应器处理效果的影响,在进水S2-浓度和有机物浓度分别为200mg·L-1和800mg·L时,适宜HRT为8h,最佳曝气量为60-90L·h-1。以厌氧反应器出水作为好氧反应器进水,在反应器内温度30±2℃、厌氧段进水pH值7.50～8.50和COD：N：P=100：5：1的条件下,完成厌氧与好氧反应器的串联。19～30d期间,厌氧-好氧串联生物脱硫体系的有机物和SO42-负荷稳定在5.8±0.1kgCOD·m-3·d-1和1.8±0.1kgS042-m-3·dq-1,相应的脱除率平均为91.2%和85.8%,理论S0产率平均为63.9%,最高可达76%左右；两个反应器内微生物量丰富,且好氧反应器内无厌氧菌污染。通过水量、水质负荷冲击以及二次启动实验,考察厌氧-好氧串联体系运行效能,结果表明该生物体系具备良好的抗冲击能力和恢复能力。在厌氧-好氧串联体系运行稳定的基础上,采用响应曲面分析法研究主要因素的影响情况并优化工艺条件,得到以理论S0产生率为主要函数响应值的模拟方程,并计算出最优工艺条件为：进水SO42-浓度1348mg·L-1,HRT为16h和曝气量165L·h-1。在该条件下运行串联体系5d,所得S0理论产率的实验结果为65.2%,与函数预测值符合良好,肯定了该模型的适用性。显著性检测结果表明所选的3个因素皆为显著项,同时HRT和进水SO42-浓度的交互作用显著于其余交互项。显微镜观察得到,沉淀池水样中富含淡黄色颗粒物质和膜片状物；扫描电镜结果表明固体硫产品由不规则的硫颗粒组成,且易汇聚形成较大硫颗粒：X射线衍射分析显示单质硫产品以斜方硫(a-sulfur)晶体的形式存在。考察了单质硫产品的组分及含量,得到产品中硫磺纯度达79%。更多还原

【Abstract】 Alkali absorption-biological flue gas desulphurization technology includes absorbtion SO2 in flue gas to SO32-/SO42- by sodium hydroxide, anaerobic reduction of SO42- to S2- by the anaerobe and aerobic oxidation of S2- to sulfur element (S0) by the aerobium. In that case, the recovery of sulfur resources are achieved. This paper concentrated on the bio-process and investigated the start-up and running of the aerobic reactor, the tandem and process optimization of the anaerobic and aerobic reactors and the analysis of the sulfur product.The biological oxidation process of sulfide to sulfur with colorless sulfur bacteria was studied in an aerobic internal circulating bio-fluidized bed reactor (effective volume=45L) with the simulation sulfide -containing wastewater as influent. The reactor was started at 30±2℃temperature and 7.00～7.50 of pH and COD:N:P=100:5:1 for the influent. After 28 days, there were a large amount of myceliums in the reactor, and the organic loading rate reached over 3.73kgCOD·m-3·d-1and 1.09kgS2-·m-3·d-1 for the sulfide loading rate. The removal efficiency of organic and sulfide were more than 70 %and 85% respectively while the theoretical yield of sulfur was 75% approximately. In addition, hydraulic retention time (HRT) and the air aeration quantity were inspected. It was demonstrated that the optimum HRT value was 8h under the influent concentration of S2- and organic respectively for 200mg·L-1 and 800mg·L-1, and the best treatment effect of aeration was obtained at 60～90L·h-1.The anaerobic and aerobic reactors were tandemed in the way of using the anaerobic enfluent as aerobic influent under the condition of 30±2℃in two reactors and 7.50～8.50 of pH and COD:N:P=100:5:1 for the anaerobic influent. During 19～30 days, the organic and the SO42- loading rates of anaerobic reactor respectively reached 5.8±0.1kgCOD·m-3·d-1 and 1.8±0.1kgSO42-·m-3·d-1 with 91.2% of the removal efficiency of organic and 85.8% of the SO42- while the theoretical yield of sulfur was 63.9% on average. Furthermore, there were a large amount of myceliums in both reactor, and the aerobic bacteria was not polluted by anaerobic. The water quantity and quality shock lading experiment and the second start-up experiment were operated to observe the run efficiency of the anaerobic-aerobic tandem system. The result showed that the system was good at anti-shocking and resume.On the base of steady running of the anaerobic-aerobic tandem system, Response surface methodology was employed to decide the reciprocal influence of three main factors and to determinate the optimum operation conditions which were calculated from the simulation equation for S0 conversion at HRT of 16h, inlet SO42- concentration of 1348 mg·L-1 and air flow of 165 L·h-1. Statistical test showed that all three factors were significant and the interaction effect of HRT and inlet SO42- concentration was more remarkable than others. The results of demonstration test for 5 days, acquiring theoretical S0 yield efficiency of 65.2% on average which extremely approximate with the predicting value, illustrated that the equation had good applicability with the reactor system.Moreover, the light microscopic photographs of the effluent from aerobic reactor showed that there were lots of sulfur granules and membranaceous sulfur in effluent water. The observation of scanning electron microscope of sulfur product showed that the product was consisted of irregular crystal grains forming into larger particles. It is inferred that the sulfur product was present in the form of rhombic sulfur (a-sulfur) by X-Ray Diffraction analysis. The component and contents were mensurated and it is testified that the purity of sulfur product was 79% approximately.更多还原