Tevfik Aysu

Effects of catalysts and solvents on liquefaction of Onopordum heteracanthum for production of bio-oils.

Milled Onopordum heteracanthum stalks were converted to liquid products in organic solvents (methanol, ethanol and acetone) with (KOH and ZnCl₂) and without catalyst in an autoclave at temperatures of 523, 543 and 563 K. Effects of liquefaction parameters such as catalyst and solvent were investigated. The percentage yields from supercritical methanol, ethanol and acetone conversions were 48.2, 50.4 and 66.2 at 563 K in the non-catalytic runs, respectively. In the catalytic run with ZnCl₂, the highest conversion (70.2%) was obtained in acetone at the same temperature. The obtained liquid products at 563 K were analyzed and characterized by elemental, Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry. 106 different compounds have been identified by GC-MS in the liquid products obtained in methanol at 563 K.

Nannochloropsis algae pyrolysis with ceria-based catalysts for production of high-quality bio-oils.

Pyrolysis of Nannochloropsis was carried out in a fixed-bed reactor with newly prepared ceria based catalysts. The effects of pyrolysis parameters such as temperature and catalysts on product yields were investigated. The amount of bio-char, bio-oil and gas products, as well as the compositions of the resulting bio-oils was determined. The results showed that both temperature and catalyst had significant effects on conversion of Nannochloropsis into solid, liquid and gas products. The highest bio-oil yield (23.28 wt%) and deoxygenation effect was obtained in the presence of Ni-Ce/Al2O3 as catalyst at 500°C. Ni-Ce/Al2O3 was able to retain 59% of the alga starting energy in the bio-oil, compared to only 41% in absence of catalyst. Lower content of acids and oxygen in the bio-oil, higher aliphatics (62%), combined with HHV show promise for production of high-quality bio-oil from Nannochloropsis via Ni-Ce/Al2O3 catalytic pyrolysis.

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.

Bio-oil production via catalytic pyrolysis of Anchusa azurea: Effects of operating conditions on product yields and chromatographic characterization.

Pyrolysis of Anchusa azurea, a lignocellulosic gramineous plant, was carried out in a tubular, fixed-bed reactor in the presence of four catalysts (Ca(OH)2, Na2CO3, ZnCl2, Al2O3). The influences of pyrolysis parameters such as catalyst and temperature on the yields of products were studied. It was found that higher temperature resulted in lower liquid (bio-oil) and solid (bio-char) yields and higher gas yields. Catalysts effected the yields of products differently and the composition of bio-oils. Liquid yields were increased in the presence of Na2CO3, ZnCl2 and Al2O3 and decreased with Ca(OH)2. The highest bio-oil yield (34.05%) by weight including aqueous phase was produced with Na2CO3 catalyst at 450°C. The yields of products (bio-char, bio-oil and gas) and the compositions of the resulting bio-oils were determined by GC-MS, FT-IR and elemental analysis. GC-MS identified 124 and 164 different compounds in the bio-oils obtained at 350 and 550°C respectively.

Catalytic pyrolysis of Alcea pallida stems in a fixed-bed reactor for production of liquid bio-fuels.

Pyrolysis of Alcea pallida stems was performed in a fixed-bed tubular reactor with and without catalyst at three different temperatures. The effects of pyrolysis parameters including temperature and catalyst on the product yields were investigated. It was found that higher temperature resulted in lower liquid (bio-oil) and solid (bio-char) yields and higher gas yields. Catalysts had different effects on product yields and composition of bio-oils. Liquid yields were increased in the presence of zinc chloride and alumina but decreased with calcium hydroxide, tincal and ulexite. The highest bio-oil yield (39.35%) by weight including aqueous phase was produced with alumina catalyst at 500 °C. The yields of bio-char, bio-oil and gas produced, as well as the compositions of the resulting bio-oils were determined by elemental analysis, TGA, FT-IR and GC-MS. 160 different compounds were identified by GC-MS in the bio-oils obtained at 500 °C.

The Liquefaction of Heracleum persicum by Supercritical Fluid Extraction

Milled Heracleum persicum stalk was converted to liquid products by using organic solvents (methanol, ethanol, acetone, and 2-butanol) with catalysts (10% NaOH or Na2CO3) and without catalyst in an autoclave at temperatures of 518, 538, and 558 K. The liquid products were extracted by liquid-liquid extraction (benzene and diethyl ether). The percentage yields from supercritical methanol, ethanol, 2-butanol, and acetone conversions were 49.1, 55.7, 58.7, and 71.0 at 558 K, respectively. In the catalytic run with NaOH, the highest conversion was obtained by using ethanol as a solvent at the same temperature. The yields of conversion were analyzed by GC-MS.

Ceria promoted deoxygenation and denitrogenation of Thalassiosira weissflogii and its model compounds by catalytic in-situ pyrolysis.

Pyrolysis of microcrystalline cellulose, egg white powder, palm-jojoba oils mixtures Thalassiosira weissflogii model compounds was performed with CeO2 at 500°C, to evaluate its catalytic upgrading mechanism. Light organics, aromatics and aliphatics were originated from carbohydrates, proteins and lipids, respectively. Dehydration and decarboxylation were the main reactions involved in the algae and model compounds deoxygenation, while nitrogen was removed as NH3 and HCN. CeO2 increased decarbonylation reactions compared to in absence of catalyst, with production of ketones. The results showed that the catalysts had a significant effect on the pyrolysis products composition of T. weissflogii. CeO2, NiCeAl2O3 and MgCe/Al2O3 catalysts increased the aliphatics and decreased the oxygen content in bio-oils to 6-7 wt% of the algae starting O2 content. Ceria catalysts were also able to consistently reduce the N-content in the bio-oil to 20-38% of that in the parent material, with NiCe/Al2O3 being the most effective.

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.

The Effect of Boron Minerals on Pyrolysis of Common Reed (Phragmites australis) for Producing Bio-oils

Pyrolysis of common reed (Phragmites australis) stalks were performed in a fixed-bed tubular reactor with (tincal, colemanite, and ulexite) and without catalyst at three different temperatures (400, 500, and 600°C) with a constant heating rate of 30°C/min and sweeping gas (N2) flow rate of 100 cm3/min. The amounts of solid (bio-char), liquid (bio-oil + water), and gaseous products were calculated and the compositions of the bio-oils were characterized by gas chromatography/ mass spectrometry. The effects of pyrolysis parameters, such as temperature and catalyst, on the product yields were investigated. The results show that both temperature and catalyst have significant effects on the conversion of Phragmites australis into solid, liquid, and gaseous products. The highest liquid yield of 34.67% by weight, including aqeous phase, was obtained with 10% ulexite at 500°C. Further, 101 different compounds were identified by gas chromatography-mass spectrometry in the bio-oils obtained at 500°C.

Catalytic liquefaction of Spirogyra gratiana transeau alga with supercritical solvents

ABSTRACT Spirogyra gratiana transeau alga was liquefied in organic solvents with and without catalyst in a cylindrical reactor at temperatures of 493, 513, and 533 K under supercritical conditions. The liquefied compounds were extracted with diethyl ether and benzene using an extraction procedure. The product yields in supercritical methanol, ethanol, and acetone were found to be 15.5, 23.7, and 34.4% at 533 K, respectively. The highest conversion to liquid products was obtained in supercritical ethanol with 10% sodium hydroxide as catalyst at the same temperature in the catalytic runs. Main chemical compounds present in the liquid product obtained in acetone without catalyst at 533 K were analyzed and characterized by gas chromatography-mass spectrometry (GC-MS).