【作者】 梁斌；

【导师】 韩振为；

【作者基本信息】 天津大学 ， 生物化工， 2007， 硕士

【摘要】 生物脱硫(BDS)是一种新型的环保型生物技术。BDS可在常温常压下利用需氧菌或厌氧菌选择性地脱除石油及其产品中的有机硫,专一切开C-S键而不破坏C-C键,从而保留了油品的热值。生物脱硫技术具有操作简单、SO2排放量和能耗较低、投资和操作费用较少等特点。生物脱硫成为21世纪极具发展潜力的脱硫技术之一。细菌固定化可以解决游离细菌生物脱硫中遇到的油水分离困难,细菌重复利用率低,耐酸碱性差和耐冲击负荷低等问题,该技术的关键是载体选择和固定化方法。本研究对一株从被石油污染的土壤中分离得到以DBT为唯一硫源生长的脱硫菌H-412的固定化进行了研究。确定了该菌在海藻酸钠、硅藻土和聚乙烯醇复合载体上的适宜共固定化条件。结果表明,以3%海藻酸钠、4%PVA、0.5%硅藻土作为固定化载体,1%氯化钙-硼酸饱和溶液作为交联剂,制备的固定化菌具有较好的脱硫活性、机械强度、传质性能和重复利用性。DBT和2-HBP对DBT的降解率有抑制作用,但固定化细菌相对于游离细菌受DBT和2-HBP浓度的影响小得多。当固定化小球中的细菌含量对小于5%时,固定化H-412菌的脱硫能力随细菌含量增加而提高,当含量大于5%时,脱硫能力随细菌含量增加而下降,细菌含量为5%时,脱硫效率达到最大值64.3%。固定化H-412菌在油相中的脱硫能力明显高于游离细菌,当油水比达到2:3时,固定化细菌在48h后对DBT的降解率仍在60%以上,而游离细菌的脱硫能力明显下降,当油水比达到2:3时,降解率已不到20%。固定化H-412菌可以多次循环使用,经过7次使用后对DBT的降解率仍可以到达65%。与游离细菌相比,固定化H-412菌对PH值的敏感性降低,稳定性得到了很大的提高。更多还原

【Abstract】 Biodesulfurization (BDS) is a newly high developing and environmentally benign biotechnology. BDS, in which anaerobic bacteria or aerobic bacteria are used in the selective removal of sulfur from petroleum and its distillates, is C-S-band-targeted but C-C-band-targeted fashion so that it can keep the caloric value of fuel. BDS technology has many advantages, such as easy manipulation, low-SO2 emission and energy consumption, low cost and so on.Biodesulfurization is hotspot in actual study, immobilized method can solve the problem that dissociative bacteria faced, such as separate oil-water difficult, bacteria reuse and lifespan short, the ability of bear acid、alkali and impact bad, etc. But the key in this technology is select carrier and method.The author study on biodesulfurization used immobilized bacteria H-412. The optimal immobilization desulfurization bacteria H-412 conditions of sodium alginate, polyvinylalcohol and SiO2 were obtained. The suit conditions of immobilization are as follows: The experiment results indicated that the immobilized cell had the optimum desulfurization effect under the conditions of 4oC saturated boracic acid including 1 % CaCl2 as cross-linking agent, 3 % SA, 4% PVA and 0.5 % diatomite as carrier, the content bacteria is 5%.The desulfurating performance of immobilized bacteria H-412 is better than free bacteria in oil desulfurization. When ratio of oil to water is up to 2/3, after 48h reaction, the degradation rate of immobilized bacteria H-412 remains above 60%, but degradation rate of bacteria low 20%. The immobilized bacteria H-412 can repeatedly use several times, after seven times circulation the immobilized bacteria remain has 65% desulfurization ratio. Compaer whit free bacteria, immobilized bacteria have low sensitivity and hight stability.更多还原