(603d) Gasification Characteristics of Methane Fermentation Residues and Aquatic Weeds

In this study, pyrolysis and steam gasification of methane fermentation residues of food waste and aquatic weeds were performed by changing experimental conditions such as reaction temperature and water vapor concentration. In the experiment, the pyrolysis and steam gasification were carried out under two different heating rates (1K/s or instant temperature raise). In the slow heating experiment, time course change of the sample weight, evolved gases and generated tar and char were monitored and analyzed under inert or steam containing atmosphere for the temperature range of 473-973 K. As a result, it was found that under inner gas atmosphere, CO₂ evolution by primary pyrolysis and H₂, CO, CH₄ evolution by secondary pyrolysis were observed for all the samples used.  On the other hand, under steam containing atmosphere, rapid H₂ evolution was observed after primary pyrolysis reaction. This may be due to the water-gas shift reaction by steam reforming.

In the rapid heating experiment, samples were inserted into the electric furnace which was pre-heated to desired temperature (873 ~ 1273K) and pyrolysis or steam gasification were performed under inert or steam containing atmosphere. At the exit of the furnace, all the effluent gases were collected to gas bag, and the total yields of the generated gases were examined using GC-MS and GC-TCD. As a result, high H₂ yield was observed from all samples under steam gasification condition. This may also be due to the water-gas shift reaction by steam reforming. In addition, with the increase of the reaction temperature, the yields of the total combustible gases also increased. Futhermore, among all the used samples, Elodea nuttallii (aquatic weed) showed the highest total combustible gases yields.