Hydrothermal gasification of tomato processing plant waste was examined in batch autoclaves at temperatures of 300-600 C and pressures of 20.0-42.5 MPa. The catalytic effects of KOH and K2CO3 at the aforementioned temperatures and pressures were also investigated. While increasing the pressure enhanced methane yield, alkali addition improved both hydrogen and methane yields. The highest yields for H2 and CH4 were recorded as 27.4 and 21.8 moles kg-1 C at 600 C and with KOH. In addition, carbon gasification efficiency (CGE) obtained was up to 86% while carbon liquefaction efficiency (CLE) was reduced to 3.5% with KOH at 600 C and 20 MPa. A product gas with a calorific value of 24.9 MJ/Nm3 was obtained during hydrothermal gasification at 500 C and 42.5 MPa, in the presence of KOH.

We gratefully appreciate the financial support of Ege University. We thank Mr. G. Serin for his support in the pre-treatment step of the bio-masses and the help during the experimental studies and analysis.

Ege University