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Whyalla, Australia

Erkelens M.,University of Adelaide | Ball A.S.,RMIT University | Lewis D.M.,University of Adelaide | Lewis D.M.,Muradel Pty Ltd
Bioresource Technology | Year: 2015

The aim of this study was to determine how the treatment of the HTL AP with activated carbon would affect both growth and chemical composition of the microalgae. Tetraselmis MUR233 was grown in HTL AP (filtered and unfiltered) at 500×, 1000×, and 2000× dilutions in hyper saline conditions. The organic nitrogen and carbon component of the HTL AP was greatly reduced with the activated carbon treatment (TKN 52,000. ±. 520. mg/L to 5900. ±. 59. mg/L; TOC 19,000. ±. 190. mg/L to 13,000. ±. 130. mg/L). Growth of Tetraselmis MUR233 was achieved on all dilutions of HTL AP, with a maximum growth observed in the AP filtered 1000× dilution treatment (0.41. ±. 0.09. g/L), this compares to a yield of 0.49. ±. 0.10. g/L when grown in traditional culture media. © 2015 Elsevier Ltd. Source

Eboibi B.E.O.,University of Adelaide | Lewis D.M.,University of Adelaide | Lewis D.M.,Muradel Pty Ltd | Ashman P.J.,University of Adelaide | Chinnasamy S.,Aban Infrastructure Pvt. Ltd
Bioresource Technology | Year: 2014

This paper proposes a two-part process for producing biocrude with reduced impurities. The biocrude was produced from hydrothermal liquefaction (HTL) of Spirulina sp. and Tetraselmis sp. in a batch reactor at both 300 and 350. °C, 5. min, and 16%. w/w solid feed composition. The resultant biocrudes were vacuum distilled at a maximum temperature of 360. °C. It was shown that biocrude quality could be enhanced without using catalyst by vacuum distillation (VD). The biocrude yield for Spirulina sp. was 36. wt% at 300. °C, 42. wt% at 350. °C, and for Tetraselmis sp. was 34. wt% at 300. °C, and 58. wt% at 350. °C. VD of Spirulina sp. biocrude obtained at 300 and 350. °C led to 62 and 67. wt% distilled biocrudes yield, respectively. VD of Tetraselmis sp. biocrude obtained at 300. °C was 70. wt%, and 73. wt% at 350. °C. The higher heating values (HHV) increased from 32. MJ/kg to 40. MJ/kg. There were substantial reductions in oxygen, metallic content, and boiling point ranges in distilled biocrudes. © 2014 Elsevier Ltd. Source

Eboibi B.E.,University of Adelaide | Lewis D.M.,University of Adelaide | Lewis D.M.,Muradel Pty Ltd | Ashman P.J.,University of Adelaide | Chinnasamy S.,Aban Infrastructure Pvt. Ltd
Bioresource Technology | Year: 2014

The biomass of halophytic microalga Tetrasel mis sp. with 16%. w/w solids was converted into biocrude by a hydrothermal liquefaction (HTL) process in a batch reactor at different temperatures (310, 330, 350 and 370. °C) and reaction times (5, 15, 30, 45 and 60. min). The biocrude yield, elemental composition, energy density and severity parameter obtained at various reaction conditions were used to predict the optimum condition for maximum recovery of biocrude with improved quality. This study clearly indicated that the operating condition for obtaining maximum biocrude yield and ideal quality biocrude for refining were different. A maximum biocrude yield of ~65. wt% ash free dry weight (AFDW) was obtained at 350. °C and 5. min, with a severity parameter and energy density of 5.21 and ~35. MJ/kg, respectively. The treatment with 45. min reaction time recorded ~62. wt% (AFDW) yield of biocrude with and energy density of ~39. MJ/kg and higher severity parameter of 7.53. © 2014 Elsevier Ltd. Source

Lee A.,University of Adelaide | Lewis D.,University of Adelaide | Lewis D.,Muradel Pty Ltd | Kalaitzidis T.,University of Adelaide | Ashman P.,University of Adelaide
Current Opinion in Biotechnology | Year: 2016

Much of the current knowledge on the hydrothermic liquefaction of biomass to biocrude is on the basis of laboratory benchtop findings, and the step up to industrial scale reactors will require a range of information that is currently either unavailable or insufficient. This work highlights a number of these issues such as the heat of reaction, process heat recovery, optimal reaction time and waste product treatment. Effects of these knowledge gaps on the reactor design, process economics, and impacts on the environment are discussed. Although technologies do exist to deal with some of these issues, their applications are often limited by economic considerations and further studies are required. © 2016 Elsevier Ltd. Source

Ward A.,University of Adelaide | Ward A.,RMIT University | Ball A.,RMIT University | Lewis D.,University of Adelaide | Lewis D.,Muradel Pty Ltd
Algal Research | Year: 2015

Anaerobic digestion can be employed to produce methane biogas from residual microalgae biomass derived from either a lipid based biofuel process or wastewater treatment. There is interest in using halophytic microalgae for biofuel production due to their potential robustness in large-scale open pond production. The anaerobic digestion of halophytic microalgae biomass would however be challenging due to the high salinities not typically experienced in anaerobic digestion scenarios. Halophytic microalgae biomass as a potential substrate feedstock for anaerobic digestion would have salinities in excess of 3.5%, which is typically found in marine environments. To investigate the anaerobic digestion of halophytic microalgae issue the first stage of the reported study focuses on the changes undertaken in the bacterial community associated with the anaerobic digestion of piggery effluent under increasing saline conditions, with the aim of establishing a saline tolerant anaerobic digestion inoculum capable of digesting feedstocks under high salinity conditions. Favourable results from this inoculum development study allowed the investigation of anaerobic digestion of halophytic microalgae. The reported results demonstrate that a saline tolerant inoculum was maintained. Subsequent denaturing gradient gel electrophoresis (DGGE) fingerprinting of the resulting halophytic bacterial community showed several halophytic methanogens. The inoculum was used to digest the halophytic microalgae. The resulting gas data showed that biogas production of 358. ±. 53. mL/g of volatile solids (VS) with a methane content of 54. ±. 4.3% methane was achieved at 7% salinity. The volume of biogas produced on a wet weight microalgae biomass basis was 122. ±. 26 and 175. ±. 25. mL/g of halophytic microalgae biomass respectively (74. ±. 2.8. wt.% moisture content). The conversion of carbon in the feedstock to methane achieved an efficiency of 26.4% and 46.6% at 3.4% and 7% salinity respectively. A halo-tolerant anaerobic digestion microbial community could be further optimized to complete the loop with nutrient recycle required with the production of halophytic microalgae based biofuels and potentially, hypersaline wastewater treatment applications. © 2014 Elsevier B.V. Source

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