การผลิตน้ำส้มควันไม้จากไม้สะเดาด้วยเตาไพโรไลซิสแบบแก๊สหมุนวนปิด (PRODUCING WOOD VINEGAR FROM NEEM WOOD BY CLOSED CIRCULATION GAS PYROLYSIS KILN)

Abstract

The present research article aims to study the optimal conditions for producing wood vinegar by the closed circulation gas pyrolysis kiln and chemical composition of the wood vinegar produced. The capacity of the pyrolysis kiln was 0.018 m³. The closed gas circulation pyrolysis kiln consists of heater, pyrolysis chamber, condenser and blower. The producer gas in the system was employed as working fluid which circulated in the system. The excess gas was filled into the gas bag. Neem wood was examined as biomass. The consumption of biomass was 2 kg. with the moisture content of 13.74% and 0.87%. The gas temperature before entering the pyrolysis kiln was varied at 300, 350 and 400^oC. The pyrolysis process was used to the principal structural decomposition of biomass by means of chemical heat, which does not burn directly. Gas circulation flow rate will be adjusted 3 levels at 0.0112, 0.0126 and 0.0137 m³/s. The experimental results indicated that the optimal conditions for producing wood vinegar by the closed circulation gas pyrolysis kiln showed gas circulation flow rate at 0.0126 m³/s and gas temperature before entering the pyrolysis kiln 400^oC. The wood vinegar production for high moisture content biomass was 36.55% by weight. Furthermore found that wood vinegar quantity will increased with increasing of the gas temperature in the pyrolysis process, due to higher temperature will affect to the rate of structural decomposition of biomass. But the high flow rate of gas circulation showed decreasing of wood vinegar quantity, due to heat will be removed quickly that make the pyrolysis time was not sufficient. The heat in the system was not fully exploited. The results from the chemical analysis by Gas Chromatograph-Mass Spectrometer (GC-MS) found that acetic acid was a main compound of wood vinegar which was 44.46%, and phenol was 0.45%. The result of testing acidity - pH was 2.976.