石油微生物脱硫过程工程研究
文献类型：学位论文
| 作者 | 李玉光 |
| 学位类别 | 博士 |
| 答辩日期 | 2009-06-04 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 刘会洲 |
| 关键词 | 生物催化脱硫（BDS） 柴油 二苯并噻吩（DBT） 固定化 壳聚糖 超顺磁性Fe3O4纳米颗粒 |
| 其他题名 | Process Engineering of Biocatalytic Desulfurization |
| 学位专业 | 化学工艺 |
| 中文摘要 | 随着燃料油质量标准和环保法规的要求越来越严格，必须开发经济、有效的燃油深度脱硫新技术。微生物脱硫（BDS）利用生物催化剂专一性脱除石油中的有机硫，其反应条件温和，能耗低，温室气体排放少，有望成为传统加氢脱硫（HDS）的补充或替代技术。本论文从生物催化剂的制备、提高生物脱硫速率、优化工艺流程等方面入手，开展了石油生物脱硫过程工程研究。 建立了高效的制备生物催化剂的方法。以廉价的DMSO代替DBT作为红平红球菌Rhodococcus erythropolis LSSE8-1培养的硫源，利用田口正交实验设计优化了脱硫菌的培养基。通过恒定pH值补料分批培养方法发酵罐高密度培养LSSE8-1菌，96 h细胞光密度OD600为60.4（约23.9 g DCW/L）。在油水比为1:2的条件下，利用静息细胞和直接发酵液对加氢柴油深度脱硫，硫含量由248 μg/g降至51 μg/g。由此表明，以DMSO为培养硫源不仅细胞脱硫活性较高，而且可以大大降低催化剂的制备费用；利用直接发酵液脱硫，可以简化生物脱硫工艺。 完成了游离细胞柴油微生物脱硫实验室规模扩试。工程菌高密度培养-柴油脱硫的批次实验发现，72 h时LSSE8-1-vgb菌OD600=57.8，在12 h内的平均脱硫速率达到46.3 μmol-sulfur/g DCW/h。在100 L的发酵罐中进行了P. delafieldii R-8脱硫菌的大规模高密度培养，并在8 L反应器中进行柴油生物脱硫反应。柴油中的硫在21 h内从550 μg/g 脱除到105 μg/g，单次脱硫率达81%。 为避免游离细胞难以重复利用及油水分离困难的缺点，对细胞进行包埋固定化，研究提高固定化细胞脱硫活性的方法。选择海藻酸钙作为合适的包埋介质。使用气体喷射挤出装置，制得粒径为1.5 mm的海藻酸钙小球，其脱硫活性是4.0 mm的1.4倍。在固定化载体中加入0.5% Span 80，细胞活性提高1.8倍；加入8 g/L磁性Fe3O4纳米颗粒，脱硫速率提高了30.7%。这是因为粒径减小、添加Span 80等能减小传质阻力，强化了固定化细胞脱硫活性。游离细胞和固定化细胞脱硫动力学符合米氏方程。 提出细菌絮凝/吸附固定化耦合进行生物脱硫的简单方法。新方法只需要在细菌培养液中添加壳聚糖和硅藻土，脱硫菌就可以成功絮凝并吸附固定化在硅藻土载体上。壳聚糖-硅藻土吸附固定化P. delafieldii R-8菌脱硫活性很高，重复使用6次活性仍保持在85%以上，能在24 h内将柴油中的硫从123 μg/g脱除到22 μg/g。 开发了利用超顺磁性纳米颗粒原位吸附分离–固定化脱硫菌进行微生物催化脱硫的新工艺。油酸铵修饰的超顺磁性Fe3O4纳米颗粒可以成功的从细菌培养发酵液或悬浮液中，直接吸附分离红球菌LSSE8-1、德氏假单胞菌R-8和基因工程菌R. erythropolis LSSE8-1-vgb。纳米颗粒能够强烈地吸附并包覆在细胞表面，对LSSE8-1的最大吸附容量达530 g DCW/g particles，被包覆的细胞具有超顺磁性特征，易于磁分离，具有与游离细胞相似的高脱硫活性，并可重复利用。研究了磁性纳米颗粒原位吸附固定化重组菌LSSE8-1-vgb在油水两相体系中的生物脱硫性能。LSSE8-1-vgb菌能专一性脱除DBT及4,6-DMDBT中硫，对模拟油的脱硫速度为22.5 μmol DBT/g DCW/h；GC-SCD分析表明，经BDS脱硫后，加氢柴油硫含量降为0，实现了柴油的超深度脱硫。论文还探讨了磁性纳米颗粒与微生物细胞之间的相互作用机理。 开发了柴油微生物脱硫过程工程。发明了一种多相分散的自吸式生化反应器。设计了完整的连续BDS工艺流程与设备，并对其过程成本进行了初步经济核算。同时还开展了P. delafieldii R-8和Klebsiella sp. LSSE-H2的混合菌同时生物脱硫、脱氮的研究，搭建了吸附脱硫－生物脱硫耦合工艺实验室装置，为耦合脱硫工艺的过程开发做了有益的探索。 |
| 英文摘要 | With the stricter environmental regulations and steady improvement of fuel oil quality, refiners are facing challenges to develop new economical and efficient methods for desulfurization of recalcitrant organic sulfur compounds. Biodesulfurization (BDS) is an environmentally-friendly method that can remove sulfur from petroleum using a series of enzyme-catalyzed reactions under ambient conditions while providing lower energy consumption and, thus, lower CO2. BDS has been considered to be a complementary as well as promising alternative to conventional hydrodesulfurization. The purpose of this thesis is to develop a diesel BDS process engineering from the point of biocatalyst preparation, improvement the desulfurization activity and optimization of process flow. Methods for the efficient production of BDS biocatalyst were established. DMSO was recommended as an appropriate sulfur source instead of expensive dibenzothiophene (DBT) for the mass production of Rhodococcus erythropolis LSSE8-1. Culture conditions were optimized by Taguchi orthogonal array experimental design methodology. High cell density cultivation with pH control and fed-batch feeding strategies was validated in fermentor. Cell concentration of 23.9 g dry cells/L was obtained after 96 h cultivation. The resting cells and the direct fermentation suspension were applied for deep desulfurization of hydrodesulfurized diesel oils. It was observed that the sulfur content of the diesel decreased from 248 to 51 μg/g when oil water phase ratio was 1:2. The biocatalyst prepared by this method with the least cost could remove sulfur from diesel efficiently, suggesting its cost-effective advantage. And, the BDS process can be simplified by directly mixing cell cultivation suspension with diesel oil. Diesel biodesulfurization middle-scale laboratory test was achieved. Results of batch diesel BDS by LSSE8-1-vgb showed that the maximum optical density at 600 nm (OD600) was 57.8 at 72 h of cultivation, and the average desulfurization rate during 12 h was 46.3 μmol DBT/g DCW/h. The high cell density P. delafieldii R-8 culture was cultivated of in a 100 L fermentor. BDS was carried out in an 8 L bioreactor. The sulfur content of diesel decreased from 550 to 105 μg/g in 21 h, providing a total desulfurization percent of 81%. Aiming for avoiding the limitation of free cells deactivation and troublesome of oil-water-biocatalyst separation, immobilization of P. delafieldii R-8 by entrapment has been studied in order to improve the BDS activity. Calcium alginate was selected as the preferred carrier. Gas jet extrusion technique was performed to produce immobilized beads. The specific desulfurization rate of 1.5 mm diameter beads was 1.4-fold higher than that of 4.0 mm. With the addition of 0.5% Span 80 and 8 g/L Fe3O4 nanoparticles, the desulfurization rate increased 1.8 and 1.3-fold, respectively. The rate of BDS was markedly enhanced most likely resulting from the increasing mass transfer of substrate to gel matrix. Kinetics of biodesulfurization by free and immobilized cells could be represented by the Michaelis–Menten equation. A novel and simple technique was developed by using chitosan flocculation and integration with cell immobilization onto celite for petroleum BDS. P. delafieldii R-8 cells were successfully flocculated and immobilized by directly adding chitosan and celite into culture broth. The one-step immobilized R-8 cells exhibited good catalytic activity and retained at least 85% of activity after six cycles of repeated-batch desulfurization. Extensive BDS of diesel oil resulted in 82% reduction of total sulfur from 123 to 22 μg/g in 24 h. In situ cell separation and immobilization bacterial cells for BDS were developed by using superparamagnetic Fe3O4 nanoparticles. After adding the magnetic fluids of ammonium oleate-modified Fe3O4 nanoparticles to the culture broth, both the R. erythropolis LSSE8-1 and P. delafieldii R-8 cells were adsorptive immobilized and then separated by external application of a magnetic field. Fe3O4 nanoparticies were strongly absorbed to the surfaces and coated the cells. The maximum adsorption amount was 530 g DCW/g particles to LSSE8-1 cells. The coated cells exhibited typical superparamagnetic behavior, providing quick and easy magnetic separation advantage. Compared to the reusable limitation of free cells, the coated cells not only had the same desulfurizing activity as free cells but could also be reused more than seven times. BDS were performed in oil/water biphasic systems by magnetic separated/immobilized recombinant LSSE8-1-vgb cells. Bacterium LSSE8-1-vgb could selectively remove sulfur from DBT and 4,6-DMDBT, and the desulfurization rate was 22.5 μmol DBT/g DCW/h. The GC-SCD analysis showed that the sulfur of content of diesel decreased to zero, indicating that BDS could produce ultra-low-sulfur petroleum oils. The mechanism of cell adsorption on oleate-modified Fe3O4 NPs was also discussed. An integrated diesel biodesulfurization process engineering system was developed. A novel multiphase dispersed self-priming bioreactor was invented. A proof of diesel BDS process flow and equipment was demonstrated, and the operating cost was also estimated. An effort of simultaneous biodenitrogenation and biodesulfurization from model diesel by co-culture of P. delafieldii R-8 and Klebsiella sp. LSSE-H2 was explored. And, an adsorption desulfurization – biodesulfurization integrated system had been set up. Preliminary effort toward the commercialization of intergeted desulfurization technique was studied in the thesis. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 157 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1192]  |
| 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 | 李玉光. 石油微生物脱硫过程工程研究[D]. 过程工程研究所. 中国科学院过程工程研究所. 2009. |
入库方式： OAI收割
来源：过程工程研究所
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