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Year 2013

Volume 4, Issue 2 April - June 2013

A Review of the Water Footprint of Biofuel Crop Production in Thailand

Piyanon Kaenchan and Shabbir H. Gheewala p.45-52
Abstract: Increase of biofuel production is an important component in the development of alternative energy in Thailand. To meet the higher amount of biofuel (targeted by Thailand Department of Alternative Energy Development and Efficiency, DEDE), a lot of biofuel feedstock production is needed which in turn requires a large volume of water for irrigation. This study assesses the water footprint (WF) of three key biofuel crops in Thailand- cassava, sugarcane, and oil palm, based on previous studies. The WF varies considerably for each region, which is characterized by different climatic conditions and agricultural production systems. The results show that the water uses per hectare of cassava, sugarcane, and oil palm lands are in the range of 7,235-9,652, 11,630-16,312, and 12,942-23,547 m3, respectively; and, the ranges of freshwater consumption in Thailand for cassava, sugarcane, and oil palm production are between 409-455, 162-276, and 965-2,353 m3 per ton of product, respectively. Although Thailand uses water for biofuel crop cultivation more efficiently than some other countries, good water management practices are still required in order to avoid the conflict between water for energy and food. These results have implications for both policy makers and farmers in terms of water management and planning.

Keywords: biofuel crops, water footprint, cassava, sugarcane, oil palm. (144 k)

Improving the Efficiency of Large-Scale Biogas Processes: Pectinolytic Enzymes Accelerate the Lignocellulose Degradation
Ulrike Schimpf, Angelika Hanreich, Pia Mähnert, Torsten Unmack, S tefan Junne,

Julian Renpenning and Rual Lopez-Ulibarri p. 53-60
Abstract: An enzyme preparation containing mainly pectinolytic activity was used to increase the hydrolysis of agricultural feedstock for production of biogas at lab and industrial-scale bioreactors under mesophilic conditions. Bioreactor performance was evaluated by determining lignocellulose degradation efficiency and specific methane yields over a residence time of 65 days for various substrates. Additionally, enzymatic activity assays were carried out in laboratory trials to investigate the hydrolytic potential of the enzyme preparation. During industrial-scale trials the viscosity (shear stress from torsion) was measured in fermentation media. At an applied concentration of 200 g enzyme preparation/t DM of maize silage in lab-scale biogas processes, the degradation of hemicellulose was enhanced and the specific methane production was increased by 42 lN/kg ODM (15%) in comparison to untreated maize silage. Using enzymatically treated rye silage, the hemicellulose was utilized to a higher degree and the specific methane production enhanced by 26 lN/kg ODM (10%). Results from the industrial trial showed that enzymatic pretreatment (100 g enzyme/t DM of substrate) of different substrate mixtures containing mainly maize silage increased the lignocellulose degradation, in particular hemicellulose and a substantial increase in specific energy production was obtained. In addition, the viscosity in the fermentation media was significantly reduced up to 18%. In conclusion, the addition of an enzyme preparation as biological treatment led to an economical operating improvement in efficiency of the biogas process.

Keywords: Lignocellulose, enzyme, biogas process, industrial biogas production, biological pretreatment. (435 k)

Screening of Thermotolerant Microalgal Species Isolated from Western Ghats of Maharashtra, India for CO2 Sequestration

Suvarna D. Manjre and Manjushri A. Deodhar p. 61-67

Abstract: Extensive work has been carried out to find suitable strain of algae which are tolerant to high concentration of CO2. In the previous studies Chlorella vulgaris (SAG 211.12), a mesophilic strain, showed CO2 sequestration upto 23% CO2 concentration. The main constraint using such strains is that they don’t tolerate temperatures beyond 35-40ºC. Hence attempts were undertaken to isolate algal strains from hot springs located across the western ghats of Maharashtra. Limnothrix redekei, Planktolyngbya crassa and Geitlerinema sulphureum could easily sequester about 28% of CO2 without hampering biomass production. High temperature adaptability (42ºC), high CO2 tolerance (23.08%), reasonably high biomass production and easy harvesting make G. sulphureum a promising candidate for the CO2 sequestration in the tropical climatic conditions. Attempts are being made here to screen the isolated strains for lipid production.

Key words: CO2 sequestration, microalgae, Cyanophyceae, hot springs. (1.27 m)

A Metropolitan Wind Resource Assessment for Bangkok, Thailand
Part 1: Wind Resource Mapping

Carina P. Paton and Kasemsan Manomaiphiboon p. 69-76

Abstract: Increased awareness of wind energy in Thailand has resulted in growing numbers of wind turbine installations in and around Bangkok province, the capital. However, little is known about the wind resource and its variation across the province. To address this, a two-part assessment was conducted, the first of which is described here: the development of a set of 1-km resolution wind resource maps at multiple heights (up to 300 m above ground level) using atmospheric modeling that was enhanced with satellite-derived land-related data to better resolve winds over urban spatial zones. Simulated wind resource maps show the annual wind resource within 100 m of the ground is poorest over the city center (<125 W m-2 at 100 m) and strongest in the southwest coastal area (up to 200 W m-2). Wind resource becomes stronger with height, and at heights of 200-300 m and above it varies little across the province (200-300Wm-2). The results found here provide input for the second paper, in which the overall technical wind resource potential is estimated for Bangkok in terms of electricity generation using geographical information system (GIS) analysis.

Keywords: Wind energy; spatial and temporal variations, atmospheric modeling; urban zones; Bangkok. (1.27 m)

Characterisation of Bio-Oil and Bio-Char from Slow-Pyrolysed Nigerian Yellow and White Corn Cobs

Joseph K. Ogunjobi and Labunmi Lajide p. 77-84
Abstract: Cobs from yellow and white corn were slow pyrolysed at 450°C in a laboratory-scaled fixed bed reactor. Product distribution obtained was: 42.6% and 44.8% condensate, 33.3% and 33.5% bio-char, and 24.1% and 21.7% non-condensable gas for white and yellow corn cobs respectively. 13.6% bio-oil was recovered from white cob condensate and 10.12% for yellow cob. The resulting bio-oil with pH of around 5 and density of ~1.1 g/cm3 was found to be stable on storage over a period of 10 months. Ash level and viscosity at 50°C were (0.12% and 0.10%) and (41.2 cSt and 20.8 cSt) in bio-oils from the cobs of yellow and white corn respectively. Characterisation with gas chromatography revealed that the bio-oil contained cellulose and lignin-derived compounds. Bio-chars from these residues have higher heating value of ~30.00 MJ/kg, pH of ~8, bulk density of ~0.220 g/cm3 and ash level of ~1.7%. Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectrometry (EDS) was used to examine the morphology and elemental composition of these bio-chars. The bio-char produced is capable of contributing 83.6 billion MJ to energy demand in Nigeria and preventing about 6.8 million tonnes of CO2 emission into the environment.

Keywords: Bio-oil, bio-char, pyrolysis, corn cob, fixed bed reactor, agricultural wastes. (1.09 m)
 

ISSN: 1906-4918
Frequency: Quartery
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