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Characterizing the disintegration behavior of distiller’s spent grain compacts during drying in superheated steam

Biomass such as spent grain is difficult to dry when it is in the slurry form. Proposed industrial solutions are to compact wet biomass first and then dry it. Compaction develops desired granular form and increases surface area for drying but also brings new technical challenges. Superheated steam (SS) drying is advantageous over hot-air drying as it is more energy efficient. A problem associated SS drying is the initial condensation leading to disintegration of biomass compacts. The current research investigates the disintegration characteristics of distiller’s spent grain (DSG) compacts while being dried in SS. The study focuses on the DSG flowability, densification characteristics and disintegration behavior of DSG compacts as affected by SS drying conditions, soluble content and particle size distribution (PSD).
DSG fractions with particle sizes from 300 to 850 µm were dried in SS at 150°C and hot-air at 45 and 150°C. Under these drying conditions bulk density and angle of repose (AOR) varied from 0.379 to 0.435 g/cm3 and 46.0 to 50.4°, respectively. The stress-relaxation data obtained during the compaction of DSG at different levels of compressive pressure (60.3-135.7 MPa), initial moisture content (15, 20 and 25% wet basis- wb) and soluble content (15 and 30%) were normalized and analyzed to determine the asymptotic modulus (EA) of the compacts. The highest EA of 174 MPa was obtained for DSG compacts produced with a compressive force of 135.7 MPa, initial moisture of 25% wb and soluble content of 0%.
The percentage increase in volume of DSG compacts during drying in SS at 110 to 150°C temperature range was between 78 to 130%. A comparison between the physical properties of SS dried and hot-air dried compacts revealed the role of SS in accelerating the release of mechanical energy stored in the compacts. An increase of dimensions and a considerable increase in the hardness and EA of the compacts was obtained by adding up to 70% (w/w) solubles or by decreasing the PSD of wet distiller’s spent grain from d(0.9)=1283.6 to 812.8 µm. This study establishes that compaction of wet biomass followed by SS drying can lead to its effective utilization.

  1. Johnson, P., S. Cenkowski and J. Paliwal. 2010. Issues with utilisation of brewers’ spent grain. Stewart Postharvest Review 6(4): 1-8.
  2. Johnson, P., S. Cenkowski and J. Paliwal. 2011a. Bulk Density and Angle of Repose of Distiller’s Spent Grain under Different Drying Methods and Soluble Concentrations. Canadian Society for Bioengineering Conference. Paper No. CSBE11-18. Winnipeg, MB. July 10-13.
  3. Johnson, P., S. Cenkowski and J. Paliwal. 2011b. Current and Potential Applications of Distiller’s Spent Grain. Canadian Society for Bioengineering Conference. Paper No. CSBE11-316. Winnipeg, MB. July 10-13.
  4. Johnson, P., Cenkowski, S., Paliwal, J., 2013a. Superheated steam drying characteristics of single cylindrical compacts produced from wet distiller’s spent grain. Canadian Society for Bioengineering Conference. Paper No. CSBE13-11. Saskatoon, SK. July 7-10.
  5. Johnson, P., Cenkowski, S., Paliwal, J., 2013b. Compaction and relaxation characteristics of single compacts produced from distiller’s spent grain. Journal of Food Engineering 116(2): 260–266.
  6. Johnson, P., S. Cenkowski, J. Paliwal and S. Arntfield. 2014a. Significance of Particle Size Distribution on the Disintegration of Compacted Spent Grain during Drying in Superheated Steam. CSBE/SCGAB Annual International Meeting. Paper No. 1908835. Montreal, QC. July 13-16.
  7. Johnson, P., S. Cenkowski and J. Paliwal. 2014b. Analysis of the disintegration of distiller’s spent grain compacts as affected by drying in superheated steam. Drying Technology: An International Journal 32(9): 1060-1070.
  8. Johnson, P., S. Cenkowski and J. Paliwal. 2014c. Effect of solubles on Disintegration of distiller’s spent grain compacts during superheated steam drying. Drying Technology: An International Journal. DOI: 10.1080/07373937.2014.967403 (Accepted, in press).
Date January 2014
CreatorsJohnson, Praveen
ContributorsPaliwal, Jitendra (Biosystems Engineering) Cenkowski, Stefan (Biosystems Engineering), Arntfield, Susan (Food Science) Kudra, Tadeusz (Biosystems Engineering) Tabil, Lope (University of Saskatchewan)
PublisherStewart Postharvest Review, Canadian Society for Bioengineering, Elsevier, Taylor & Francis, American Society of Agricultural and Biological Engineers
Source SetsUniversity of Manitoba Canada
Detected LanguageEnglish

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