| 题名 | 发酵-渗透汽化耦合高效生产丁醇的工艺研究 |
| 作者 | 李敬 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 万印华 |
| 关键词 | 丁醇 渗透汽化 产物原位分离 两级渗透汽化 经济评估 |
| 其他题名 | Fermentation-pervaporation coupled process for efficient butanol production |
| 学位专业 | 生物化工 |
| 中文摘要 | 生物质原料转化生物丁醇是发展可再生能源的重要选择。然而，在丁醇发酵过程中存在着严重的产物抑制，阻碍了生物丁醇的发展。渗透汽化原位分离技术能够有效解除丁醇对细胞的抑制，是提高生物丁醇产率的有效途径之一。本文就发酵-渗透汽化耦合技术生产过程中涉及到的一系列问题进行了研究，取得的主要成果如下： 1）制备了有机-无机杂化渗透汽化膜，考察了不同超滤底膜对渗透汽化复合膜性能的影响，结果表明，以聚丙烯腈（PAN）超滤膜为底膜时，选择性较高，性能稳定。同时，研究了操作条件和发酵液组成对silicalite-1/PDMS/PAN渗透汽化复合膜分离性能的影响。渗透液中总溶剂浓度、丁醇的最低移除速率都与料液中溶剂浓度相关。 2）以葡萄糖为基质生产丁醇，考察了发酵-渗透汽化耦合过程对生物丁醇生产的影响。在分批发酵渗透汽化耦合过程中，菌体浓度升高，葡萄糖的消耗速率和产率分别比传统分批发酵提高40%和28%。渗透汽化膜的通量在774-552 g/m2?h左右，丁醇分离因子在28-31之间。 在连续发酵渗透汽化耦合过程中，当稀释率为0.0117 h-1时，最大产率和最大葡萄糖消耗速率分别比分批发酵高203% 和155%。当稀释率降低到0.0038 h-1，渗透液中的总溶剂浓度能够达到160.0 g/L，得率提高到0.37 g/g，比分批发酵中提高21.88%。膜的通量和选择性随着发酵液中溶剂浓度变化略有波动，总体保持稳定；且整个操作过程中，膜污染不明显。 3）利用响应曲面分析法，对木薯培养基进行优化。以木薯为发酵底物，连续发酵渗透汽化耦合实验进行304 h，底物消耗速率、总产率和总得率分别提高58%，81%和15%。渗透液中丁醇浓度高达122.4 g/L，经相分离后，有机相中丁醇浓度达到501.1 g/L。和分批发酵过程相比，能够节省11.85%的生产成本和34%的能耗。 为了进一步浓缩渗透液分相产生的水相，对其进行两级渗透汽化，获得的溶液与有机相混合，溶剂浓度分别是丁醇393.77 g/L，丙酮186.62 g/L，乙醇18.78 g/L，ABE 599.17 g/L，高于目前文献报道的溶剂浓度。 4）利用SuperPro Designer软件对分批发酵蒸馏工艺、连续发酵渗透汽化耦合工艺和连续发酵两级渗透汽化耦合工艺进行化工流程设计和经济性评价。研究发现，渗透汽化耦合工艺，能够降低发酵设备和蒸馏设备的投资成本、操作成本和原料成本，但是增加了膜及膜组件成本。综合计算，分批发酵蒸馏工艺生产丁醇的成本为17.52￥/kg，连续发酵渗透汽化耦合工艺和连续发酵两级渗透汽化耦合工艺分别降低至14.20￥/kg和13.78￥/kg，低于传统工艺。 |
| 英文摘要 | Bio-butanol is a promising fuel energy using renewable biomass. In situ product recovery technique by pervaporation could relieve the inhibiton of butanol. In this dissertation, a series of problems involved in biobutanol fermentation-pervaporation couped prossese was investigated. The principal results was as follows: 1) Three kinds of ultra-filtration membranes were used as the substrate for pervaporation membrane. Silicalite-1/PDMS/PAN had a higher selectivity and stability. The influence of operationg conditions and fermentation components on the pervaporation performance was investigated. Silicalite-1/PDMS/PAN membrane was used to remove acetone, butanol and ethanol from ABE model solution, ABE concentration in the permeate solution and the removal rate of ABE were correlated to the solvent concentration in feeding solution. 2) Fermentation kinetics in batch coupled process was investigated, the glucose consumption rate and productivity were increased by 40% and 28% compared to batch fermentation without PV. Total flux ranged from 552 to 774 g/m2?h, butanol separation factor ranged between 28 and 31. The pervaporation (PV) performance of silicalite-1/PDMS/PAN composite membrane was investigated in the continuous acetone-butanol-ethanol (ABE) production by a fermentation-PV coupled process. Results showed that continuous removal of ABE from the broth at three different dilution rates greatly increased both the solvent productivity and glucose utilization rate by 160 %, in comparison to the control batch fermentation. The high solvent productivity reduced the acid accumulation in the broths because most acids were re-assimilated by cells for ABE production. Therefore, a higher total solvent yield of 0.37 g/g was obtained in the fermentation-PV coupled process, with a highly concentrated condensate containing 89.11–160.00 g/L ABE. During 268 h fermentation-PV coupled process, the PV membrane showed a high ABE separation factor of more than 30 and a total flux of 486-710 g/m2?h. Membrane fouling was negligible for the three different dilution rates. The solution-diffusion model, especially the mass transfer equation, was proved to be applicable to this coupled process. 3) Response surface methodology was used to optimize the culture medium. Production of acetone-butanol-ethanol (ABE) from cassava was investigated by in situ removing butanol from fermentation broth and alleviating the toxity to the Clostridium acetobutylicum DP217 with a fermentation-pervaporation coupled process. Compared to the control batch fermentation, glucose consumption rate and solvent productivity increased by 15% and 21%, respectively when batch ABE fermentation was integrated with pervaporation separation; while in continuous fermentation-PV coupled process running for 304 h, the substrate consumption rate, solvent productivity and yield increased by 58%, 81% and 15%, reaching 2.02 g/L?h, 0.76 g/L?h and 0.38 g/g, respectively. Silicalite-1 filled PDMS/PAN membrane modules ensured media recycle without much fouling, while generating a highly concentrated permeate solution containing 201.8g/L ABE with 122.4g/L butanol. After phase separation, a final product containing 584 g/L ABE with 501.1 g/L butanol was obtained. Therefore, the fermentation-PV coupled process has the potential to decrease production cost and energy consumption in ABE production. 4) Simulation with Software SuperPro Designer was performed for the butanol production of batch distillation, continuous fermentation-pervaporation coupled process and continuous fermentation-two stage pervaporation coupled process. Results indicated that, with pervaporation couped process, the fermentation and distillation equipment purchase cost, operation cost and the raw materials cost were reduced. While the membrane and membrane module cost were appended. Butanol production cost was estimated to be 17.52￥/kg in batch fermentation distillation process. In continuous fermentation-pervapo |
| 语种 | 中文 |
| 公开日期 | 2015-07-08 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/15517]  |
| 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 | 李敬. 发酵-渗透汽化耦合高效生产丁醇的工艺研究[D]. 中国科学院研究生院. 2014. |
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