Municipal solid waste was pyrolyzed in a tubular reactor under vacuum. The effect of pyrolysis temperature and holding time on the product yields were investigated and the optimum conditions for pyrolysis were settled. The products of the pyrolysis were liquid pyrolytic oil, solid char and gaseous mixture. The pyro-oil was collected in a series of ice-cooled collectors. The uncondensed gas was blown off and the solid char was collected from the pyrolyser as a residue. The pyro-oil was then analyzed for fuel properties and chemical composition. The experimental result of gas chromatography & mass spectroscopy showed that the pyro-oil derived from the pyrolysis of municipal solid waste contained considerable amounts of carbonyl groups and/or oxygen content, resulting in low pH and low heating value.
Biogas, produced from organic waste through anaerobic digestion (AD), is mainly composed of methane (CH4) and carbon dioxide (CO2) with smaller amount of hydrogen sulfide (H2S) and nitrogen (N2). Trace amount of some other gases are occasionally present in biogas. For electricity generation from biogas, reduction of H2S is necessary because it is toxic and corrosive to most of the equipments. Reduction of Hydrogen Sulfide (H2S) from poultry based biogas (normally it contents 1500~2500 ppm) can be done by dosing air/oxygen to the main digester during the digestion process. Two methods of air injection technique have been followed for optimization of the process. Firstly two hour interval air injection and secondly air injection based on percentage of hourly gas production. The optimum air percentage to minimize H2S should be at least 3.00%. After aeration H2S level comes to the desired level (<50ppm) within 1.5-2.0 hours and remains constant up to 7-9 hours and biogas can be used for effective power generation. A complete aeration system has been developed which is simple and cost effective for H2S reduction to the desired level from poultry based biogas plant. This system can be applied for any size of poultry based biogas plant for effective power generation. Key words: Anaerobic digestion; Hydrogen Sulfide (H2S); Aeration; Biogas digester; Power generation DOI: http://dx.doi.org/10.3329/bjsir.v46i3.9040 BJSIR 2011; 46(3): 339-342
The purposes of the work to study the fatty acid methyl ester production by transesterification of Jatropha curcus oil with different catalysts where methanol was used as solvent. Jatropha oil having high free fatty acids FFA (14.02%) was processed in two steps. First step is acidcatalyzed esterification by using 1% H 2 SO 4 , 40% methanol-to-oil to produce methyl esters by lowering the acid value, and next step is different base-catalyzed transesterification. As part of ongoing efforts to investigate different homogeneous, heterogeneous and solid acid catalysts for biodiesel synthesis, the catalytic activity of KOH, NaOH, Ca(OH) 2 , activated Ca(OH) 2 , Hß zeolite and montmorillonite were studied for the transesterification of Jatropha oil. Among these catalysts, performance of catalysts order are KOH > NaOH > activated Ca(OH) 2 >Ca(OH) 2 > montmorillonite> Hß zeolite.
Mineralogical analysis of Moheskhali beach sands revealed the presence of high amount of ilmenite. About 50% of these ilmenites are unaltered which are characterized by the presence of exsolution of ilmenite with hematite, ilmenite with magnetite, and ilmenite with rutile. Others (50%) are unexsolved where 30-50% grains partially or fully altered. These altered and unaltered phases of ilmenite are confirmed by X-Ray diffraction study. Ilmenite-hematite exsolution comprising 70-80% of the total exsolution. The widely banded exsolved phases were formed by continuous exsolution mechanism while the second generation thinner bands were formed discontinuously. Seriate texture dominates (about 75%) over emulsion, granular, quadrangular, sub graphic, veined and special types. Optical study suggests that the alteration of ilmenite is seen to proceed along grain boundaries and/or fractures resulting in an amorphous to microcrystalline mass resembling leucoxene. The chemical composition of the alteration products of ilmenite frequently fluctuates within definite ranges (pseudoilmenite and pseudorutile ranges) of a nonstoichiometric composition and thus deviates from their ideal composition. Key words: Ilmenite; Rutile; Opaque; Exsolution; Alteration. DOI: 10.3329/bjsir.v45i1.5173 Bangladesh J. Sci. Ind. Res. 45(1), 17-26, 2010
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