High moisture corn stover pelleting in a flat die pellet mill fitted with a 6 mm die: physical properties and specific energy consumption

Journal Article · Mon Jun 15 00:00:00 EDT 2015 · Energy Science & Engineering

DOI:https://doi.org/10.1002/ese3.74· OSTI ID:1212450

Tumuluru, Jaya Shankar ^[1]

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1. Idaho National Lab. (INL), Idaho Falls, ID (United States). Biofuels and Renewable Energy Technology Dept.

The quality and specific energy consumption (SEC) of the biomass pellets produced depend upon pelleting process conditions. The present study includes understanding the effect of feedstock moisture in the range of 28–38% (wet basis [w.b.]) and preheating in the range of 30–110°C at two die speeds of 40 and 60 Hz on the physical properties and SEC. A flat die pellet mill fitted with a 6 mm die was used in the present study. The physical properties of pellets such as moisture content, unit, bulk and tapped density, durability, and expansion ratio and SEC of the pelleting process are measured. The results indicate that the pellets produced have durability values in the range of 87–98%, and unit bulk and tapped density in the range of 670–1100, 375–575, and 420–620 kg/m³. Increasing the feedstock moisture content from 33% to 38% (w.b) decreased the unit, bulk and tapped density by about 30–40%. Increasing feedstock moisture content increased the expansion ratio and decreased the density values. A higher feedstock moisture content of 38% (w.b.) and higher preheating temperature of 110°C resulted in lower density and a higher expansion ratio, which can be attributed to flash off of moisture as the material extrudes out of the die. The SEC was in the range of 75–275 kWh/ton. Higher feedstock moisture content of 38% (w.b.) and a lower die speed of 40 Hz increased the SEC, whereas lower to medium preheating temperature (30–70°C), medium feedstock moisture content of 33% (w.b.), and a higher die speed of 60 Hz minimized the SEC to <100 kWh/ton.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: AC07-05ID14517
• OSTI ID: 1212450
• Report Number(s): INL/JOU-14-33648
• Journal Information: Energy Science & Engineering, Vol. 3, Issue 4; ISSN 2050-0505
• Publisher: Society of Chemical Industry, Wiley
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
high moisture corn stover
pellet properties
pelleting
specific energy consumption