Pattarapon Rungsri, Pornlada Daorattanachai, Navadol Laosiripojana and Unalome Wetwatana Hartley

Abstract: The catalytic partial oxidation of methane over Ni/GDC (Gd-doped CeO₂) and Cu/GDC was investigated at temperature range 400-650°C. It was found that Ni/GDC catalyst exhibited excellent performance towards CH₄ conversion and H₂ yield. On the other hand, Cu/GDC showed poor catalytic activity toward partial oxidation reaction because copper metal could promote complete oxidation reaction instead of partial oxidation reaction. Nevertheless, the coupling of Ni/GDC and Cu/GDC could increase H₂ yield from the reaction, which could be mainly due to the promotion of water gas shift reaction by Cu/GDC.

Keywords: Ni based catalyst; Cu based catalyst; GDC; Partial oxidation; Hydrogen.

Bancha Panyacharoen, Navadol Laosiripojana, Verawat Champreda and Marisa Raita

Abstract: Two-stage fractionation is a promising method to improve the efficiency of hemicellulose and lignin removal, leading to high purity of cellulose fraction. In this study, hemicellulose content was firstly removed by hydrothermal process using formic acid underoptimal conditions. The subsequence step was aimed to separate lignin fraction from cellulose content via organosolv pretreatment using different organic solvents (methyl isobutyl ketone; MIBK and dimethyl sulfoxide; DMSO with varying reaction parameters. The optimal two-stage fractionation contained in hydrothermal process with MIBK and water in ratio 80: 20 and 5%v/v formic acid at 180ºC for 80 min, resulting in the highest lignin yield and cellulose recovery with 65.36% and 64.69% respectively. After bleaching process with 1% sodium chlorite (NaClO₂), it led to decrease in lignin content from 33.54 to 5.94%w/w reflected to increasing cellulose fraction from 46.60 to 91.73%w/w- compared to the pretreated sample. Fourier-transform infrared spectroscopy (FTIR) revealed efficient removal of non-cellulosic components, resulting in exposed cellulose microfibers with a reduced crystalline size as determined by X-ray diffraction (XRD). With potential on obtaining high purified cellulose, the work demonstrated potential of two-stage pretreatment from sugarcane bagasse using hydrothermal and organosolv process in presence of formic acid catalyst for further converting to value added cellulose products in biorefineries.

Keywords: Bagasse, fractionation, bleaching, hydrothermal.

Chonticha Rajrujithong and Nakorn Worasuwannarak*

Abstract: We have recently presented “Degradative solvent extraction” to upgrade as well as to dewater low rank coal and biomass wastes at 350℃using 1-methylnapthalene (1-MN). In this work we examined the possibility to use kerosene as a practical solvent to upgrade biomass in reference to 1-MN.  It was found that the thermal degradation behavior of Leucaena in kerosene and 1-MN was rather similar. The yields of the solvent treated biomass (STB) using kerosene and 1-MN were close to each other.  At 350℃as large as 71.1%, and 73.3% of carbon were recovered in the STBs prepared from using kerosene and 1-MN, respectively. The higher heating values (HHV) of the STBs were as high as 29.9 MJ/kg, and 30.9 MJ/kg for the STBs prepared from using kerosene and 1-MN, respectively. These results showed that kerosene was very effective to upgrade biomass by solvent treatment method.

Keywords:Biomass, Upgrading, Degradative solvent extraction.

Luv Kumar Chhetri* and Boonrod Sajjakulnukit

Abstract: A study to ascertain energy consumption pattern by household sector in urban region of Bhutan was conducted in Thimphu, Capital City of Bhutan, in 2017. Questionnaire was developed on the use of various forms of energy sources namely, electricity, liquefied petroleum gas, kerosene and firewood on energy consumption by different end-use applications in a household. From the 525 household respondents, it was found that electricity (59.69%) is the most preferred household energy mix, followed by liquefied petroleum gas (22.31%). Highest energy mix was consumed by space heating end-use (38.58%), pursued by cooking (29.65%) of the total final energy mix consumed in the household sector because: Bukhari (Traditional metal oven fed with biomass) and kerosene heater were also used beside electrical heaters for space heating, while cooling load was negligible. On the total share of electricity consumption, 34.47% was consumed for space heating, followed by 20.69% for hot water supply and least, 4.04% on entertainment. Above 90% of the household owned and used appliances like rice cooker, water boiler, television and refrigerator indicating consumer preferences towards electrical appliances and fuel choice. On average, a household here consumes approximately 4,500 kWh per year and spends BTN 1200 (1USD=64BTN, Bhutanese Currency Ngultrum) in winter and BTN 600 in summer month on electricity. Operating time and penetration of appliances are the main characteristics that attributes to the disparity in energy consumption under different income classes. Adoption of energy efficient technologies in probable end-use application would bring in considerable energy saving in household energy consumption and similar future study would determine the impact on implementation of such efficient technologies.