Comments on the Paper “Estimation of Energy for Hydrocarbon Extraction in Biofuel Production from Microalgae”

抄録

A paper in press with this journal and accessible via Science Direct and Scopus¹⁾ that compared four solvent extraction gives a description in its ‘results and discussion’ about DME extraction²⁾. The authors of Ref. 1) have the following to say about DME extraction: Several hundreds of times more DME needs to extract oil from microalgae. This is very difficult to follow, and I am confused by the description of DME amount cited from a laboratory-scale test²⁾.
Next, extraordinary Fig. 2 is ‘pulled out of a hat.’ In the cited study, we used an extraction column (diameter, 11.6 mm; length, 190 mm)²⁾. Moreover, we described ‘microalgae were loaded into the lower half of the extraction column,’ and ‘DME flow rate was 10 cm³ · min⁻¹.’ It should be emphasized that the test was conducted by a very short fix-bed extractor.
It goes without saying that in practical applications, DME should be circulated in the liquid state until the extracted oil become sufficiently inspissated in the same manner as other common industrial practices in the field of extraction.
Maybe the authors of Ref. 1) did not know counter-current multiple extraction? DME was not circulated but was used one time only, which resulted in considerable DME consumption. The discussion in Ref. 1) takes no note of these and is therefore difficult to accept. Moreover, there is no description supporting the comparison and all that can be said is that a reader cannot be expected to attach any importance to them.