Flash pyrolysis products from hazelnut shell and tea factory waste obtained in a pyrolysis apparatus were analyzed. Comparison of the pyrolytic products of the structural components indicates the origin of each product. A promising route for processing biomass is pyrolytic conversion, which has been conducted under a variety of experimental conditions, resulting in production of charcoal, tarry material, aqueous fraction and gaseous products. Methanol can be produced by pyrolysis of biomass. Methanol mainly arises from methoxyl groups of uronic acid and from the breakdown of methyl esters and/or ethers from decomposition of pectin-like plant materials. Acetic acid comes from the elimination of acetyl groups originally linked to the xylose unit. The pyroligneous acid consists of about 50% methanol, acetone, phenols and water. The yields of acetic acid from hazelnut shell for non-alkali and alkali runs increased from 12.80% to 16.30% and from 16.70% to 22.18% while the final pyrolysis temperature was increased from 675 to 825 K, respectively. The yields of methanol from hazelnut shell for non-alkali and alkali runs increased from 7.26% to 10.30% and from 9.72% to 12.61% while the final pyrolysis temperature was increased from 675 to 875 K, respectively. The maximum yields of acetic acid from tea waste for non-alkali and alkali runs were 7.13% and 9.20% at 825 K, respectively. The maximum yields of methanol from tea waste for non-alkali and alkali runs were 8.82% (at 875 K) and 10.50% (at 925 K), respectively. (C) 2002 Elsevier Science Ltd. All rights reserved.