Background2,3-Butanediol (2,3-BDO) is a synthetic chemical compound that also can be produced by biomass fermentation, which is gaining share in the global market as an intermediate product for numerous applications, i.e. as liquid fuel or fuel additive. Several metabolic engineering fermentation strategies to enhance the production of 2,3-BDO were developed. However, the recovery of 2,3-BDO from its fermentation broth remains a challenge due to its low concentration and its solubility in water and other components. Thus, a cost-effective recovery process is required to deliver the required purity of 2,3-BDO. This paper presents a new process development and techno-economic analysis for 2,3-BDO purification from a fermentation broth.ResultsConventional distillation and hybrid extraction-distillation (HED) processes are proposed in this study with detailed optimization and economic analysis. Particularly, a systematic solvent selection method was successfully implemented to determine a good solvent for the proposed HED configuration based on numerous experimental data obtained with each solvent candidate. NRTL and UNIQUAC property methods were evaluated to obtain binary interaction parameters of 2,3-BDO through rigorous Aspen Plus regression and validated using experimental data. Total annual cost (TAC)-based optimization was performed for each proposed configuration. Even though the HED configuration required 9.5% higher capital cost than conventional distillation, placing an extraction column before the distillation column was effective in removing water from the fermentation broth and significantly improved the overall process economics.ConclusionsOleyl alcohol was found to be the most suitable solvent for the HED of 2,3-BDO due to its high distribution coefficient and high selectivity. The proposed HED drastically reduced reboiler duty consumption and TAC by up to 54.8 and 25.8%, respectively. The proposed design is expected to be used for the commercial scale of 2,3-BDO production from fermentation process.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1013-3) contains supplementary material, which is available to authorized users.

For the development of lithium ion recovery process from seawater, a series of experimental researches were performed. Solvent extraction of lithium ion from aqueous solution using kerosene as solvent was proposed. Lithium ion is effectively extracted by thenoyltrifluoroacetone-trioctylphosphine oxide (TTA-TOPO) in kerosene within 80 min. Extraction efficiency is severely influenced by stoichiometric parameters. Among the stoichiometric parameters, volume ratio of aqueous (A) to extraction (E) solution is the most influential parameter. After extraction, lithium ion could be easily stripped from the extraction solution by acidic solutions. Stripping efficiency decreases with pH of acidic solutions, and the kind of acid does not affect the stripping efficiency. Extraction efficiency maintains at more than 93 % even when the extraction solution is recycled three times. 65 % of lithium ion can be extracted from seawater by this solvent extraction process when magnesium ion is precipitated by NH 4 OH prior to solvent extraction process. Other metallic ions in seawater decrease the extraction efficiency of lithium ion.

Butanediol has attracted interest as a promising drop-in fuel, mainly due to its high antiknock index and high heating value. Microbial production of 2,3-butanediol is considered more environmentally friendly and sustainable than chemical-based production methods. However, to achieve the 99% purity required for use as fuel, the dehydration and purification steps associated with the microbial production process consume tremendous amounts of energy. This high energy consumption limits the feasibility of the microbial production process at the commercial scale. A commercially feasible and sustainable 2,3-butanediol production process is proposed based on an energy efficient extraction-assisted distillation scheme. On the basis of economic, technical, and environmental considerations, isobutyl alcohol and 1-butanol were chosen as suitable solvents for the proposed scheme. Regression analysis and data validation were applied to verify the incorporated experimental data which was then used in the well-established commercial process simulator Aspen Plus. Results indicate that the overall energy efficiency of the purification step of the microbial 2,3-butanediol production process can be improved greatly, with up to 24.5% and 31.3% reductions in total annualized cost for the isobutyl alcohol-and 1-butanol-based designs, respectively.

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This paper presents a novel hybrid process combining thermally coupled reactive distillation with membrane-based pervaporation for enhanced production of n-butyl acetate. A conventional reactive distillation process was used as the base case and first optimized for the transesterification of methyl acetate with n-butanol to produce n-butyl acetate. It was observed that methyl acetate recovered in the recycle stream significantly affects the conversion in the reactive distillation column and overall energy efficiency of the whole process. The existing and proposed configurations were evaluated and optimized by simulation in Aspen Plus. The integration of thermally coupled reactive distillation and pervaporation improved the energy efficiency of the reactive distillation process by preventing remixing effect in the reactive distillation column and eliminating the azeotropic nature of the methanol and methyl acetate in the recycle stream, respectively. Finally, integration of the thermally coupled reactive distillation with a commercial pervaporation membrane was explored to take synergistic advantage of the thermally coupled reactive distillation and pervaporation hybrid configuration. As a result, the proposed hybrid design showed remarkably improved energy efficiency and economics. The total reboiler duty and total annual cost reduced to 63 and 43%, respectively, compared to those of the base case.