EFFECT OF LIGNIN ON WHEAT-STRAW PREPYROLYSIS

The prepyrolysis of delignified wheat straw is studied. Aqueous alkali ne (NaOH-Na2CO3, NaOH-NaHCO3) as well as organosolv alkaline (NaOH-eth anol, NaOH-isopropanol) delignification methods were used. Pretreated straw was thermochemically converted to a solid bio-fuel at 270 degree s for 30 min. Prepyrolysis dry yield and gross caloric value of the ma terial produced were determined to characterize the behaviour of pretr eated material during heating and the effects of delignification. The prepyrolytic behaviour of the pretreated material can be described by simple mathematical formulae. In particular, prepyrolysis dry yield is generally a linear function of lignin content, i.e. degree of deligni fication; moreover, the caloric value of the solid fuel produced after prepyrolysis can also be linearly expressed with lignin content or de lignification.