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Chemistry and Industry of Forest Products ›› 2017, Vol. 37 ›› Issue (6): 35-42.doi: 10.3969/j.issn.0253-2417.2017.06.005

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Effect of Alkali Lignin on Corn Stalk Pelleting Process

LI Weizhen1,2,3, JIANG Yang1,2,3, RAO Shu4, YIN Xiuli1,2,3, JIANG Enchen4   

  1. 1. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China;
    2. CAS Key Laboratory of Renewable Energy, Guangzhou 510640, China;
    3. Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China;
    4. School of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
  • Received:2017-04-11 Online:2017-12-25 Published:2018-01-05

Abstract: In order to study the effect of alkali lignin on corn stalk pelleting process and the bonding mechanism, the influences of four parameters(alkali lignin adding amount, temperature, moisture and pressure) on three technical indicators(relaxed density, radial compressive strength and specific energy consumption) were investigated. The compression molding experiment showed that when alkali lignin adding amount increased from 0 to 20%, the relaxed density of corn stalk pellets increased from 1 005 kg/m3 to 1 157 kg/m3 and the radial compressive strength increased from 1 353 N to 1 930 N. This results suggested that increasing of alkali lignin could promote the corn stalk pelleting process. The thermal transition temperatures of corn stalk and alkali lignin were also studied by differential scanning calorimetry(DSC). The results showed that the glass transition temperatures of corn straw and alkali lignin were between 92.5-103℃ and 61-137℃, respectively. In the thermal transition temperature range, 100℃ was the lowest specific energy consumption with suitable moisture content. The suitable temperature range for alkali lignin bonding was 100-130℃.The microstructure of pellets showed that alkali lignin occurred melting transition after melting temperature and then formed ‘molten combination’ and ‘mechanical interlocking’ inside the particles. The suitable alkali lignin adding amount for bonding was 10%-15%.

Key words: pelleting, alkali lignin, bonding mechanism, specific energy consumption, thermal transition, microstructure

CLC Number: