See Hoon Lee

Co-pyrolysis characteristics of sawdust and coal blend in TGA and a fixed bed reactor

Co-pyrolysis characteristics of sawdust and coal blend were determined in TGA and a fixed bed reactor. The yield and conversion of co-pyrolysis of sawdust and coal blend based on volatile matters are higher than those of the sum of sawdust and coal individually. Form TGA experiments, weight loss rate of sawdust and coal blend increases above 400 degrees C and additional weight loss was observed at 700 degrees C. In a fixed bed at isothermal condition, the synergy to produce more volatiles is appeared at 500-700 degrees C, and the maximum synergy exhibits with a sawdust blending ratio of 0.6 at 600 degrees C. The gas product yields remarkably increase at lower temperature range by reducing tar yield. The CO yield increases up to 26% at 400 degrees C and CH(4) yield increases up to 62% at 600 degrees C compared with the calculated value from the additive model.

Hydrogen Conversion of Syngas by Using WGS Reaction in a Coal Gasifier

A gasification process with pre-combustion CO2 capture process, which converts coal into environment-friendly synthetic gas, might be promising option for sustainable energy conversion. In the coal gasification for power generation, coal is converted into H2, CO and CO2. To reduce the cost of CO2 capture and to maximize hydrogen production, the removal of CO and the additional production of hydrogen might be needed. In this study, a 2l/min water gas shift system for a coal gasifier has been studied. To control the concentration of major components such as H2, CO, and CO2, MFCs were used in experimental apparatus. The gas concentration in these experiments was equal with syngas concentration from dry coal gasifiers (H2: 25-35, CO: 60-65, CO2: 5-15 vol%). The operation conditions of the WGS system were 200-400℃, 1-10bar. Steam/Carbon ratios were between 2.0 and 5.0. The commercial catalysts were used in the high temperature shift reactor and the low temperature shift reactor. As steam/carbon ratio increased, the conversion (1-COout/COin) increased from 93% to 97% at the condition of CO: 65, H2: 30, CO2: 5%. However the conversion decreased with increasing of gas flow and temperature. The gas concentration from LTS was H2: 54.7-60.0, CO2: 38.8-44.9, CO: 0.3-1%.