Behavior of Chars from Bursa Mustafa Kemal Paşa Alpagut and Balıkesir Dursunbey Çakirca Lignite (Turkey) during Non-catalytic and Catalytic Gasification

Abstract

The reactivities of chars obtained by pyrolysis of Bursa Mustafa Kemal Paşa Alpagut lignite and Balıkesir Dursunbey Çakırca lignite (Turkey) at different temperatures were determined by CO₂ gasification and by combustion with O₂. Catalytic effect of Na₂CO₃ on the CO₂ and O₂ gasification reactivity of chars was investigated. Gasification tests were performed in the fixed bed reactors operating at ambient pressure. Reactivity of chars during the CO₂ gasification reactions was determined by calculating the reaction rate constants and reactivity of chars during the O₂ gasification was determined by using ignition temperatures of the samples. Activation energies and Arrhenius constants of the chars on the CO₂ gasification reactions were also calculated by the help of Arrhenius curves. The activation energy for CO₂ gasification was generally decreased with pyrolysis temperature, due to the different surface characteristics and different nature of carbon atoms gasified as the gasification reactions proceed. Generally, the increase in pyrolysis temperature leads to an increase in gasification reactivity with CO₂. The reactivity of chars in catalytic gasification was higher than the corresponding non-catalytic reactivity of the same chars. Ignition temperature increased with increasing pyrolysis temperature.

Keywords:

• catalytic effect
• gasification
• ignition temperature
• pyrolysis
• reactivity
• Turkish lignite