Separation of solvent from microalgal hydrocarbon using nanofiltration
Lim, King Zheng (2016) Separation of solvent from microalgal hydrocarbon using nanofiltration. Honours thesis, Murdoch University.
The need for searching an alternative technology to separate solvent efficiently from the post-extraction process in the algae fuel production process has been long researched for, and little to no convincing findings were found to rectify the current energy crisis. This report aims to evaluate the viability of implementing nanofiltration technology that could replace the use of a distillation column in the post-extraction process. Aspen Plus was used to assess the thermodynamic feasibility of utilising chemical process unit operations. This includes the following: investigation of the effect of thermodynamic property methods to generate a more realistic separation process based on the nonideality of the feed mixture, optimization of the simulation via sensitivity analysis, and an overall energy balance to determine its sustainability based on the calorific value of the hydrocarbon extracted from an algae culture. Nanofiltration experiments were carried out to establish the applicability of the membrane purchased from Sterlitech and possibly fill a current void in research for utilising the Duracid membrane in a heptane solution. The experiments covered: the effect of different contact times with heptane, the effect of pressure and feed concentration variance. A stirred cell was used to facilitate the experiment, and several parameters were done to determine the characteristics of the membrane, which included permeating de-ionised water, heptane, and squalene-heptane. Results showed that prolonged contact times with heptane worsen the permeating performance of the membrane over time, and a maximum of 6% rejection value was attained when using Duracid membrane. Higher operating pressure and lower feed concentration also enhanced the permeate flux. Possible explanation for such occurrence includes the nanofiltration driving force, membrane polarity difference to the solvent, and membrane swelling. Although GCMS showed a little rejection value for retaining squalene in heptane solution, the finding is significant that could prove solvent separation via nanofiltration is possible and future work is needed to improve the outcome. Alternative separation technology and solvent resistant nanofiltration membrane had been proposed, and that could serve as another starting point for an efficient separation process.
|Publication Type:||Thesis (Honours)|
|Murdoch Affiliation:||School of Engineering and Information Technology|
|Supervisor:||Bahri, Parisa and Moheimani, Navid|
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