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Biomass conversion processes

Three different biomass conversion processes, thermochemical, chemical and biochemical, are reviewed based on the results of some investigations. The important parameters for thermochemical processes are temperature, pressure, time at reaction conditions and added reactants or catalysts, for chemical processes are acid concentration, prehydrolysis, temperature, time at reaction conditions and kind and moisture of used material and for biochemical processes are reaction temperature, pH, moisture and time at reaction conditions.

Applications on agricultural and forest waste adsorbents for the removal of lead (II) from contaminated waters

At present, there is growing interest in using low cost, commercially available materials for the adsorption of heavy metals. The major advantages of adsorption technologies are its effectiveness in reducing the concentration of heavy metal ions to very low levels and the use of inexpensive adsorbent materials. In this review, agricultural and forest waste adsorbents were used to remove Pb2+ ions in wastewater treatment, and their technical feasibilities were reviewed in studies mainly from 2000 to 2010. They all were compared with each other by metal binding capacities, metal removal performances, sorbent dose, optimum pH, temperature, initial concentration and contact time. Although commercial activated carbon is widely used in wastewater treatment applications, it has high costs. The use of agricultural by-products as adsorbent material to purify heavy metal contaminated water has become increasingly popular through the past decade because they are less expensive, biodegradable, abundant and efficient. Instead of activated carbon, this study was focused on the inexpensive materials such as agricultural and forest waste. It was shown that these alternative adsorbents had sufficient binding capacity to remove Pb2+ ions from wastewater.

Liquid products from Verbascum stalk by supercritical fluid extraction

Abstract Verbascum stalk mill was converted to liquid products by using organic solvents, such as methanol, ethanol and acetone, with catalysts (10% NaOH or ZnCl 2 ) and without catalyst in an autoclave at temperatures of 533, 553 and 573 K. The liquid products were extracted by liquid–liquid extraction using benzene and diethyl ether. The yields from supercritical methanol, ethanol and acetone extractions were 44.4, 43.3 and 60.5 wt%, respectively, at 573 K. In the catalytic runs with methanol and ethanol, the extracts were 52.4 and 44.8% using 10% NaOH and 55.5 and 60.6% using ZnCl 2 , respectively, at 573 K. The yields from supercritical methanol increased from 38.2 to 52.4% as the temperature was increased from 533 to 573 K in the catalytic run.

Liquefaction of Typha latifolia by supercritical fluid extraction.

Milled Typha latifolia stalk mill was converted to liquid products by using organic solvents (methanol, ethanol, acetone and 2-butanol) with catalysts (10% NaOH or Na(2)CO(3)) and without catalyst in an autoclave at temperatures of 518, 538 and 558 K. The products were extracted by liquid-liquid extraction (benzene and diethyl ether). The percentage yields from supercritical methanol, ethanol, 2-butanol and acetone conversions were 55.0, 58.5, 62.7 and 70.5 at 538 K, respectively. In the catalytic run with NaOH, the highest conversion was obtained by using ethanol as a solvent at the same temperature. Conversion yields were analyzed by GC-MS. The aim of the present study was to obtain an alternative for petroleum derived fuels or chemical raw materials.

Recovery of boric acid from boronic wastes by leaching with water, carbon dioxide- or sulfur dioxide-saturated water and leaching kinetics

Abstract B 2 O 3 was recovered from waste samples such as borogypsum, reactor waste, boronic sludges, waste mud and concentrator waste by leaching processes using distilled water, sulfur dioxide- and carbon dioxide-saturated water. In the leaching processes, temperature, stirring time and solid-to-liquid ratio were taken as parameters. The amount of B 2 O 3 leached increased with increasing temperature and stirring time and it also increased with decreasing solid-to-liquid ratio, but the increase was less than that recorded for the leaching temperature and the stirring time. SO 2 saturated water is a more effective leaching solvent than CO 2 saturated water for boronic wastes. By the end of the experiments, more than 90% of B 2 O 3 recovery was found as boric acid. In the leaching of boric acid from boronic wastes in water saturated with sulfur dioxide, it was observed that the leaching rate increases with increasing temperature and leaching time. The overall average values of the kinetic parameters were: apparent activation energy ( E ) 33.2 kJ mol −1 , pre-exponential factor ( A ) 8.2×10 9 min −1 , reaction order ( n ) 0.97 and rate constant ( k ) 3.37×10 3 min −1 for the leaching processes of the boronic wastes.

Kinetic study on hydrolysis of biomass (Ailanthus altissima chips) by using Alkaline-glycerol solution

Abstract This paper is about the kinetics of hydrolysis of biomass ( Ailanthus altissima ) using an aqueous alkaline-glycerol solution. The study was performed at four temperature levels (438, 458, 478 and 498 K) and for different times (1, 2, 3, 4, 5, 6, 7 and 8 hours). The solution concentration was constant (75 g glycerol, 25.0 g water, 10% NaOH and 10.0 g wood chips). After conversion has been determined, the fractional weight loss ( −1/W 0 d W/ d t ) was found to be a function of the amount of wood residue ( f ( W )) and the reaction rate constant ( k ). The order of reaction ( n ) and activation energy ( E a ) were calculated. The results were, respectively, 1.32×10 −2 s −1 , 1.16, and 19.5 kJ mol −1 .

RECENT ADVANCES IN BIOHASS TECHNOLOGY

Abstract The concept that blomass represents a source of liquid fuel and of different raw materials has led to the development of various research programmes In this field. Our Investigations in this direction are based on the following premises: (1) all kinds of blomass incorporate almost the same components, (2) energy from conventional forestry (forest energy) and from energy plantations (energy forestry), (3) energy from wood powder as an upgraded wood fuel, (4) the macromolecular compounds existing in the blomass Incorporate biosynthesis energy, and their conversion to useful products, (5) oils by liquefaction of blomass with different catalytic and noncatalytic processes, and (6) by conversion of blomass to solid, liquid, and gaseous fuels by pyrolysis and gasification.

Optimization of process variables for supercritical liquefaction of giant fennel

Milled giant fennel (Ferula orientalis L.) stalks were treated in supercritical solvents in the presence of catalyst in a high pressure reactor. Effects of process variables including temperature (from 240 to 320 °C), solvent (2-propanol, 2-butanol, and acetone), catalyst (Na2CO3, NaOH, and ZnCl2), particle size (from 0.224 > Dp > 0.150 to 0.850 > Dp > 0.425), solvent/mass ratio (from 50/5 to 50/15) and reaction time (from 45 to 95 min) on product yields were investigated. The amounts of solid, liquid and gas produced, as well as the properties of the resulting bio-oils were determined. Temperature, catalyst and reaction time were major factors affecting the product yields and composition of bio-oils. The highest conversion (liquid + gas products) of 73.48% was achieved in acetone with 10% zinc chloride at 320 °C. Acetone as solvent, zinc chloride (10%) as catalyst, 0.224 > Dp > 0.150 as particle size, 50/5 as solvent/mass ratio, and 80 minutes as reaction time provide the optimum conditions for the supercritical liquefaction of Ferula orientalis L. The liquid products (bio-oils) obtained at 300 °C were analyzed by gas chromatography-mass spectrometry (GC-MS). The bio-oils which contained a higher amount of carbon and hydrogen than that of the original raw material had higher heating values ranging from 23.66 to 26.17 MJ kg−1.

PYROLYSIS OF BLACK LIQUOR BY USING SOME BASIC CATALYSTS

Abstract Catalytic pyrolysis for the production of liquids and gases from acidic precipated of black liquor was carried out by using CaO and CuCO3,Cu(OH)2 catalysts. This process has been studied in the temperature range from 463 to 570 K. Pyrolysis of black liquor in the temperature range 463–570 K gave yields which increased from 25·9 to 29·0 % as the catalyst percentages was increased from 5 to 20 % for CaO. Under the same conditions, the yields of pyrolysis increased from25·5 to 28·3 for CuCO3.Cu(OH)2.