The Combustion Characteristics of Waste Liquor from Renewable Plant-Derived Chemical Polyol Processing

An experimental study was carried out to investigate the combustion characteristics of plant-derived polyol liquor waste using thermogravimetric analyzer and vertical tube furnace tests. The research results showed that the waste liquor combustion reaction comprised four processes: evaporation, pyrolysis, combustion, and inorganic salt reaction, and that a wave peak exists for each process. The pyrolysis process, which is the most violent reaction, exhibited the maximum peak weight-loss rate and weight-loss ratio and had the lowest activation energy and frequency factor. The peak weight-loss rate of inorganic salt reaction process was less than that during the combustion process, but sodium alkali has catalytic effect at high temperature, which makes the activation energy and the frequency factor of inorganic salt reaction process less than that of the combustion process. The ignition temperature of the waste liquor in the vertical tube furnace was lower than the temperature in the thermogravimetric analyzer. The ignition temperature of pyrolysis volatiles measured in a vertical tube furnace was less than 700 °C but the ignition temperature of carbon combustion as measured with TG – DTG was 718 °C. When the temperature inside vertical tube furnace was higher than 800 °C, the waste liquor combustion process becomes almost instantaneous (about 8 s) and is violent, which produces more residual carbon content in the combustion products as a longer holding time is necessary to ensure that the reaction is completed.