Thitima Sornpitak and Nakorn Worasuwannarak*
Abstract: Three washing techniques namely water at room temperature, hot water, and hydrochloric acid were applied to rice straw to remove the inorganic matters. The ash content and elemental composition of washed rice straw were examined in detail. Then, the pyrolysis behaviors and gas formation rate during the pyrolysis of washed biomass were examined using TGA and TG-MS techniques. It was found that water could easily remove alkali metal and Cl, but water could not remove alkaline earth metals. On the other hand, hydrochloric acid could significantly remove alkali and alkaline earth metals. However, silicon cannot be removed by washing because of the strong bonding between amorphous silica and biomass matrix. Washing significantly affected the pyrolysis behavior of biomass. The weight change curves during the pyrolysis of washed biomass increased by approximately 20°C in temperature. It was found that the amount of tar produced during the pyrolysis increased significantly, whereas the amount of H2O decreased significantly by washing. From these measurements, the effect of inorganic matters on the pyrolysis behavior of biomass was examined in detail.
Keywords: Rice straw, washing, pyrolysis behavior, gas formation rate.
Promporn Keeratiisariyakul, Patrick Rousset* and Adisak Pattiya
Nway Ei Aung, Sebastien Bonnet* and Savitri Garivait
Abstract: Fire is an important disturbance factor in terrestrial ecosystems of the world including Southeast Asia (SEA). Fires contribute emissions of carbon and other trace gases impacting air quality and human health. In this study, the temporal variations in vegetation fires based on burned areas and related carbon emissions in SEA were studied with a particular focus on Myanmar based on data retrieved from the Global Fire Emission Database (GFED) over the period 2000-2015. The potential influence of climatic conditions on vegetation fires, in particular El Nino and La Nina years were also investigated. It was found that burned areas and carbon emissions relate to crop land, savanna, peat and forest, and vary significantly among SEA countries. The fire season spreads mostly from January to May each year with a peak usually observed in March and April. The largest emissions of carbon in SEA are from Indonesia due to its extensive peat land cover and burning, particularly during El Nino years. However, excluding peat land related carbon emissions, Myanmar was found to be the largest contributor to carbon emissions mostly from forest and savanna fires. In Myanmar, although some correlation was observed between normal precipitation and monthly variations in BAs, there was no evidence of a strong correlation between yearly variations in burned areas and climate conditions related to El Nino and La Nina years. Although further investigations should be performed in regard of the above investigations, these initial results may highlight the potential influence of anthropogenic activities on vegetation fires.
Keywords: Global Fire Emission Database, Burned Areas, Carbon Emissions, Oceanic Niño Index, Southeast Asia.
Nang Phyu Phwe and Amnat Chidthaisong*