细胞固定化生物脱硫工艺过程研究
文献类型：学位论文
| 作者 | 罗明芳 |
| 学位类别 | 博士 |
| 答辩日期 | 2003 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 中国科学院过程工程研究所 |
| 导师 | 刘会洲 |
| 关键词 | 生物脱硫 细胞培养 微生物催化脱硫 细胞固定化 |
| 其他题名 | Studies on Processes of Biodesulfurization and Cell Immobilization |
| 学位专业 | 化学工艺 |
| 中文摘要 | 微生物催化脱硫具有反应条件温和、设备投资和操作费用低等优点,能选择性脱除加氢脱硫技术难以脱除的含硫稠环类化合物,是实现石油及其产品深度脱硫最有效的技术之一.脱硫微生物细胞固定化是将生物脱硫推向工业化的有效途径之一.该论文以柴油生物脱硫为研究背景,开展了细胞固定化生物脱硫工艺过程研究.采用氯化钡沉淀和傅立叶变换红外(FTIR)光谱确认脱硫菌从二苯并噻吩(Dibenzothiophene,DBT)中脱除的硫最终以硫酸盐的形式存在于水相.对细胞生长条件的研究表明,细胞生长时间、生长硫源及浓度等因素对所得细胞的脱硫活性产生影响,处于对数生长期的细胞脱硫活性最大.二甲基亚砜是替代DBT进行高密度脱硫细胞培养的理想硫源.用硫饥饿的方法可有效增加脱硫菌的脱硫活性,最大可提高至原来的5.5倍.对柴油脱硫的研究发现,菌株R-8和R-9对硫含量分别为1807和852.1mg/L的高硫直馏柴油均具有较好的脱硫能力,脱硫率为50~60%.使用气相色谱和原子发射光谱(GC-AED)对脱硫前后柴油中的硫组分进行分析,发现菌株R-8对DBT及其烷基取代衍生物的脱硫活性大于对烷基取代噻吩类硫化物的脱硫活性.表明生物脱硫与加氢脱硫具有很好的互补性. |
| 英文摘要 | Biodesulfurization (BDS) has the advantages of cost- and energy-efficiency. Moreover, BDS can selectively remove sulfur from condensed thiophenes recalcitrant to hydrodesulfurization (HDS). It is expecting to be complementary or alternative to HDS for deep desuifurization of petroleum and its products. For BDS to reach the commercial application, cell immobilization will attract more and more attention in the future. The aim of this thesis is to investigate the process of biodesulfurization based on the background of diesel oil desuifurization by immobilized cells. The sulfur removed from dibenzothiophene (DBT) by resting cells of Pseudomonas delqfieldii R-8 and Nocardia globerula R-9 was released in the form of sulfate, which was identified by BaCb precipitation and FTIR. Sulfate repressed the formation of desulfurizing enzymes of gram-negative strain R-8, but was not inhibitory to desuifurization activity. It showed that the desuifurization activity of cells in logarithm phase was the highest. Dimethyl sulfoxide (DMSO) was considered as an optimal sulfur source for high cell density cultivation. The desuifurization activity of cells of strain R-8 could be increased about 5.5-fold with sulfur starvation treatment. Effects of aqueous media, cell concentration, volume ratio of oil-to-water and DBT concentration on desuifurization activity of resting cells of strain R-8 and R-9 were studied. It showed that the kinetics of DBT desuifurization could be represented by the Michaelis-Menten Equation. The desuifurization of DBT and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) in a mixture proceeded simultaneously without preference for either one of them. Desuifurization activity could be maintained at high level even at a high volume ratio of oil-to-water (5:1) and high concentration of NaCl up to 60 g/L. Strain R-8 and R-9 showed high desulfurization capability for two straight-run diesels with initial sulfur content of 1807 mg/L. 50-60% of sulfur could be desulfurized by either one of them. GC-AED analysis was used to evaluate the effect of strain R-8 treatment on the distribution and content of organic sulfur-containing compounds in straight-run diesel oil. The results showed that desulfurization activity of this strain for alkyl-DBTs was much higher than that for alkyl-thiophenes. High cell density cultivation was crried out in a 5 L fermentor for mass production of desulfurizing cells. Kinetics of growth and DBT desulfurization were investigated in batch and fed-batch cultivation. 17 g dry cells/L of cell density could be achieved by appropriate control of pH, dissolved oxygen and sulfur source. The highest specific desulfurization activity of these cells could be reached to 16 mmol DBT kg"'(dry cells) h"1. Cell immobilization was carried out by entrapment and adsorption, respectively. Alginate-immobilized cells of strain R-8 could be repeated desulfurization of model oil for more than 218 h. Hydrophobic polyurea-coating alginate-immobilized cells showed higher desulfurization activity and dispersion characteristics in oil phase than those without coating alginate-immobilized cells. Celite-immobilized cells showed high desulfurization stability in the model oil system. The desulfurization activity was high even after repeated BDS of model oil for more than 550 h. Chitosan-celite complex carriers with high magnetism were made using co-precipitation of chitosan with nanometer Fe3C>4 and celite. Immobilized cells adsorbed on this carrier showed high desulfurization activity. It is easier and more quickly to recover both the oil and the biocatalysts using magnetic-immobilized cells. |
| 语种 | 中文 |
| 公开日期 | 2013-09-16 |
| 页码 | 171 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1380]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 罗明芳. 细胞固定化生物脱硫工艺过程研究[D]. 中国科学院过程工程研究所. 中国科学院过程工程研究所. 2003. |
入库方式： OAI收割
来源：过程工程研究所
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