Olive bagasse (Olea europea L.) pyrolysis

Olive bagasse (Olea europea L.) was pyrolysed in a fixed-bed reactor. The effects of pyrolysis temperature, heating rate, particle size and sweep gas flow rates on the yields of the products were investigated. Pyrolysis runs were performed using pyrolysis temperatures between 350 and 550 degrees C with heating rates of 10 and 50 degrees C min(-1). The particle size and sweep gas flow rate varied in the ranges 0.224-1.8mm and 50-200 cm3 min(-1), respectively. The bio-oil obtained at 500 degrees C was analysed and at this temperature the liquid product yield was the maximum. The various characteristics of bio-oil obtained under these conditions were identified on the basis of standard test methods. The empirical formula of the bio-oil with heating value of 31.8 MJ kg(-1) was established as CH(1.65)O(0.25)N(0.03). The chemical characterization showed that the bio-oil obtained from olive bagasse may be potentially valuable as a fuel and chemical feedstock.     

Pyrolysis of grape bagasse: effect of pyrolysis conditions on the product yields and characterization of the liquid product

In this study, pyrolysis of grape bagasse was investigated with the aim to study the product distribution and their chemical compositions and to identify optimum process conditions for maximizing the bio-oil yield. Particular investigated process variables were temperature (350-600 °C), heating rate (10-50 °C/min) and nitrogen gas flow rate (50-200 cm³/min). The maximum oil yield of 27.60% was obtained at the final pyrolysis temperature of 550 °C, sweeping gas flow rate of 100 cm³/min and heating rate of 50 °C/min in a fixed-bed reactor. The elemental analysis and heating value of the bio-oils were determined, and then the chemical composition of the bio-oil was investigated using chromatographic and spectroscopic techniques such as column chromatography, ¹H NMR and FTIR. The fuel properties of the bio-oil such as flash point, viscosity and density were also determined. The bio-oils obtained from grape bagasse were presented as an environmentally friendly feedstock candidate for bio-fuels.     

Catalytic pyrolysis of Miscanthus x giganteus over activated alumina

The catalytic effects of activated alumina (Al(2)O(3)) on the pyrolysis of Miscanthusxgiganteus, a new energy crop, were investigated. Catalytic pyrolysis experiments carried out under static and nitrogen atmospheres were performed in a fixed-bed reactor. The final pyrolysis temperature was kept constant at 550 degrees C in all of the experiments. The effect of catalyst loading (by weight of feedstock as 10%, 20%, 40%, 60%, 80% and 100%), heating rate (10 degrees C and 50 degrees Cmin(-1)), nitrogen flow rate (50, 100, 150 and 200cm(3)min(-1)) on the pyrolysis conversion and product yields were investigated. The results were compared with those obtained in non-catalytic pyrolysis. Activated alumina catalyst has a strong influence on the Miscanthusxgiganteus pyrolysis product and conversion yield. Furthermore, the catalytic bio-oils obtained from catalytic pyrolysis under static and nitrogen atmospheres were examined using elemental analysis, column chromatography, Fourier transform infrared (FTIR) and nuclear magnetic resonance ((1)H NMR) spectroscopy methods.     

Fixed-bed catalytic pyrolysis of cotton-seed cake: effects of pyrolysis temperature, natural zeolite content and sweeping gas flow rate

Catalyzed pyrolysis of cotton-seed cake was studied under different experimental conditions. Variables investigated were pyrolysis temperature, zeolite content and sweeping gas flow rate. Experiments were carried out isothermally. Liquids, gases and char were obtained as products of pyrolysis. The distributions of these products were determined for various contents (1, 5, 10, 20 wt.% of raw material) of zeolite at four different pyrolysis temperatures. The maximum liquid yield obtained was 30.84% at a pyrolysis temperature of 550 degrees C with a sweeping gas flow rate of 100 cm(3) min(-1) in the presence of clinoptilolite (20% based on raw material) as catalyst. The pyrolytic and catalytic liquid products were analysed in detail to determine the predominant chemical classes and the identities of the major compounds present.     

Fast pyrolysis of soybean cake: product yields and compositions

This study was an investigation of the role of important parameters influencing pyrolysis yields from soybean cake. Experiments were carried out at temperatures ranging from 400 to 700 degrees C, for various nitrogen flow rates, heating rates and particle sizes. The maximum liquid yield was 42.83% at a pyrolysis temperature of 550 degrees C with a sweeping gas rate of 200 cm3 min(-1) and heating rate of 700 degrees C min(-1) for a soybean cake sample having 0.425 < D(p) < 0.85 mm particle size. The various characteristics of liquid product were identified. Thus, the aliphatic sub-fraction of the bio-oil was analysed by GC-MS and further structural analyses of bio-oil and aromatic and polar sub-fractions were conducted using FT-IR and 1H-NMR. The H/C ratios and the structural analysis of the fractions obtained from the biocrudes showed that the fractions were quite similar to currently utilised transport fuels.     

Thermal analysis and devolatilization kinetics of cotton stalk, sugar cane bagasse and shea meal under nitrogen and air atmospheres

Thermal degradation, reactivity and kinetics for biomass materials cotton stalk (CS), sugarcane bagasse 1 (SB1), sugarcane bagasse 2 (SB2) and shea meal (SM) have been evaluated under pyrolysis (N(2)) and oxidising (dry air) conditions, using a non-isothermal thermogravimetric method (TGA). In the cases of CS and SB1 the peak temperatures were 51 degrees C higher for pyrolysis compared with oxidative degradation, whereas for SB2 and SM the difference was approximately 38 degrees C. However, the differences in the rates of weight loss were significantly higher under oxidising conditions for all the materials studied. Maximum rate of weight loss (%s(-1)) under pyrolysis conditions ranged from 0.10 to 0.18 whereas these values accelerated to the range of 0.19-0.28 under oxidising conditions, corresponding to respective peak temperatures. Samples ranked in order of reactivity (R(M)x10(3)) (%s(-1) degrees C(-1)) are CS=1.31 approximately SM=1.30>SB2=1.14>SB1=0.94 for air and CS=0.54>SB2=0.49>SB1=0.45>SM=0.31 for nitrogen. Shea meal exhibited a complex char combustion behaviour indicating that there may be two distinct types of char derived from fibrous and woody components in the original material. Activation energy calculations were based on the Arrhenius correlation.     

Volatilisation of alkali and alkaline earth metallic species during the pyrolysis of biomass: differences between sugar cane bagasse and cane trash

Sugar cane bagasse and cane trash were pyrolysed in a novel quartz fluidised-bed/fixed-bed reactor. Quantification of the Na, K, Mg and Ca in chars revealed that pyrolysis temperature, heating rate, valence and biomass type were important factors influencing the volatilisation of these alkali and alkaline earth metallic (AAEM) species. Pyrolysis at a slow heating rate (approximately 10 K min(-1)) led to minimal (often <20%) volatilisation of AAEM species from these biomass samples. Fast heating rates (>1000 K s(-1)), encouraging volatile-char interactions with the current reactor configuration, resulted in the volatilisation of around 80% of Na, K, Mg and Ca from bagasse during pyrolysis at 900 degrees C. Similar behaviour was observed for monovalent Na and K with cane trash, but the volatilisation of Mg and Ca from cane trash was always restricted. The difference in Cl content between bagasse and cane trash was not sufficient to fully explain the difference in the volatilisation of Mg and Ca.     

Succinoylation of sugarcane bagasse under ultrasound irradiation

The chemical modification of sugarcane bagasse with succinic anhydride using pyridine as solvent after ultrasound irradiation was studied. The optimized parameters included ultrasound irradiating time 0-50 min, reaction time 30-120 min, succinic anhydride concentration by the ratio of dried sugarcane bagasse to succinic anhydride from 1:0.25 to 1:1.50, and reaction temperature 75-115 degrees C are required in the process. The extent of succinoylation was measured by the weight percent gain (WPG), which increased with increments of reaction time, succinic anhydride concentration, and reaction temperature. The ultrasound irradiation has a positive effect on bagasse succinoylation process. On the other hand, the ultrasonic pre-treatment application broke down the cell wall polymers, resulting in, therefore, a negative effect on the WPG. Evidences of succinoylation were also provided by FT-IR and CP MAS (13)C NMR and the results showed that the succinoylation at C-2 and C-3 occurred. The thermal stability of the succinylated bagasse decreased upon chemical modification.     

Study of banana and coconut fibers Botanical composition, thermal degradation and textural observations

Four fibers from banana-trees (leaf, trunk) and coconut-tree (husk, fabric) were examined before their incorporation in cementitious matrices, in order to prepare insulating material for construction. Their botanical compositions have been determined following a method described previously. Thermal degradation of these fibers were studied between 200 and 700 degrees C under nitrogen gas flow. Temperature of pyrolysis was the experimental parameter investigated. The solid residues obtained were analyzed by classical elemental analysis, Fourier Transform Infra Red (FTIR) spectroscopy and were observed by Scanning Electron Microscopy (SEM). This study has shown (1) the relation between botanical, chemical composition with both localization of fibers in the tree and type of tree; (2) the rapid and preferential decomposition of banana fibers with increasing temperature of pyrolysis and (3) the rough samples are made of hollow fibers.     

Fast pyrolysis of rice husk: Product yields and compositions

A series of pyrolysis oils and chars were prepared from agricultural by-product rice husk by the lab-scale fast pyrolysis system using induction heating. The effect of process parameters such as pyrolysis temperature, heating rate, holding time, nitrogen gas flow rate, condensation temperature and particle size on the pyrolysis product yields and their chemical compositions was examined. The maximum oil yield of over 40% was obtained at the proper pyrolysis conditions. The chemical characterization by elemental, calorific, spectroscopic and chromatographic studies showed that the pyrolysis oils derived from the fast pyrolysis of rice husk contained considerable amounts of carbonyl groups and/or oxygen content, resulting in low pH and low heating values.     

Sunflower shells utilization for energetic purposes in an integrated approach of energy crops: laboratory study pyrolysis and kinetics

Sunflower is a traditional crop which can be used for the production of bioenergy and liquid biofuels. A study of the pyrolytic behaviour of sunflower residues at temperatures from 300 to 600 degrees C has been carried out. The experiments were performed in a captive sample reactor under atmospheric pressure and helium as sweeping gas. The yields of the derived pyrolysis products were determined in relation to temperature, with constant sweeping gas flow of 50 cm3 min(-1) and heating rate of 40 degrees Cs(-1). The maximum gas yield of around 53 wt.% was obtained at 500 degrees C, whereas maximum oil yield of about 21 wt.% was obtained at 400 degrees C. A simple first order kinetic model has been applied for the devolatilization of biomass. Kinetic constants have been estimated: E=78.15 kJ mol(-1); k(0)=1.03 x 10(3)s(-1).     

Acetylation of sugarcane bagasse using NBS as a catalyst under mild reaction conditions for the production of oil sorption-active materials

Sugarcane bagasse was esterified with acetic anhydride using N-bromosuccinimide as a catalyst under mild conditions in a solvent free system. The extent of acetylation was measured by weight percent gain, which varied from 2.1% to 24.7% by changing the reaction temperature (25-130 degrees C) and duration (0.5-6.0 h). N-Bromosuccinimide was found to be a novel and highly effective catalyst for acetylation of hydroxyl groups in bagasse. At a concentration of 1% of the catalyst in acetic anhydride, a weight percent gain of 24.7% was achieved at 120 degrees C for 1 h, compared with 5.1% for the un-catalyst reaction under the same reaction condition. FT-IR and CP-MAS 13C-NMR studies produced evidence for acetylation. The thermal stability of the products decreased slightly upon chemical modification, but no significant decrease in thermal stability was observed for WPG > or = 24.7%. More importantly, the acetylation significantly increased hydrophobic properties of the bagasse. The oil sorption capacity of the acetylated bagasse obtained at 80 degrees C for 6 h, was 1.9 times higher than the commercial synthetic oil sorbents such as polypropylene fibres. Therefore, these oil sorption-active materials can be used to substitute non-biodegradable materials in oil spill cleanup.     

Pyrolysis of olive residue and sugar cane bagasse: non-isothermal thermogravimetric kinetic analysis

Thermal degradation and kinetics for olive residue and sugar cane bagasse have been evaluated under dynamic conditions in the presence of nitrogen atmosphere, using a non-isothermal thermogravimetric method (TGA). The effect of heating rate was evaluated in the range of 2-50 K min(-1) providing significant parameters for the fingerprinting of the biomass. The DTG plot for the olive residue and sugar cane bagasse clearly shows that the bagasse begins to degrade at 473 K and exhibits two major peaks. The initial mass-loss was associated with hemicellulose pyrolysis and responsible for the first peak (538-543 K) whereas cellulose pyrolysis was initiated at higher temperatures and responsible for the second peak (600-607 K). The two biomass mainly devolatilized around 473-673 K, with total volatile yield of about 70-75%. The char in final residue was about 19-26%. Mass loss and mass loss rates were strongly affected by heating rate. It was found that an increase in heating rate resulted in a shift of thermograms to higher temperatures. Ozawa-Flynn-Wall and Vyazovkin methods were applied to determine apparent activation energy to the olive residue and sugar cane bagasse. Two different steps were detected with apparent activation energies in the 10-40% conversion range have a value of 153-162 kJ mol(-1) and 168-180 kJ mol(-1) for the hemicellulose degradation of olive residue and sugar cane bagasse, respectively. In the 50-80% conversion range, this value is 204-215 kJ mol(-1) and 231-240 kJ mol(-1) for the cellulose degradation of olive residue and sugar cane bagasse, respectively.     

Production of pyrolytic liquids from industrial sewage sludges in an induction-heating reactor

With the application of induction-heating, the pyrolytic experiments have been carried out for three sewage sludges from the food processing factories in an externally heated fixed-bed reactor. The thermochemical characteristics of sludge samples were first analyzed. The results indicated that the calorific value had about 15 MJ/kg on an average, suggesting that it had a potential for biomass energy source. However, its nitrogen concentration was relatively high. From the thermogravimetric analysis (TGA) curves, it showed that the pyrolysis reaction can be almost finished in the temperature range of 450-750 degrees C. The yields of resulting liquid and char products from the pyrolysis of sewage sludge were discussed for examining the effects of pyrolysis temperature (500-800 degrees C), heating rate (200-500 degrees C/min), and holding time (1-8 min). Overall, the variation of yield was not so significant in the experimental conditions for three sewage sludges. All results of the resulting liquid products analyzed by elemental analyzer, pH meter, Karl-Fischer moisture titrator and bomb calorimeter were in consistence with those analyses by FTIR spectroscopy. Furthermore, the pyrolysis liquid products contained large amounts of water (>73% by weight) mostly derived from the bound water in the biosludge feedstocks and the condensation reactions during the pyrolysis reaction, and fewer contents of oxygenated hydrocarbons composing of carbonyl and nitrogen-containing groups, resulting in low pH and low calorific values.     

Effect of pyrolysis temperature on composition, surface properties and thermal degradation rates of Brazil Nut shells

Changes in chemical and surface characteristics of Brazil Nut shells (Bertholletia excelsa) due to pyrolysis at different temperatures (350 degrees C, 600 degrees C, 850 degrees C) were examined. For this purpose, proximate and ultimate analyses, physical adsorption measurements of N2 (-196 degrees C) and CO, (25 degrees C) as well as samples visualisation by scanning electronic microscopy (SEM) were performed. Appreciable differences in the residue characteristics, depending markedly on the pyrolysis temperature, were observed. Release of volatile matter led to the development of pores of different sizes. Progressive increases in micropore development with increasing pyrolysis temperature took place, whereas a maximum development of larger pores occurred at 600 degrees C. Furthermore, kinetics measurements of Brazil Nut shells pyrolysis from ambient temperature up to 900 degrees C were performed by non-isothermal thermogravimetric analysis. A model taking into account the significant changes in the residue during pyrolysis, through an increase in the activation energy with temperature and solid conversion, were found to properly fit the kinetics data over the wide range of degradation investigated.     

Bioconversion of cellulose into ethanol by Clostridium thermocellum--product inhibition

Direct anaerobic bioconversion of cellulosic substances into ethanol by Clostridium thermocellum ATCC 27405 has been carried out at 60 degrees C and pH 7.0 (initial for 100 L) under continuous sparging of oxygen free nitrogen in a culture vessel. Raw bagasse, mild alkali-treated bagasse, and solka floc were used as substrates. The extent of conversion of raw bagasse (cellulose, 50%; hemicellulose, 25%; lignin, 19%) was observed as 52% (w/w) and 79% (w/w) in the case of mild alkali and steam-treated bagasse (cellulose, 72%; hemicellulose, 11%; lignin, 12%), respectively. Use of bagasse concentration above 10 g/L showed a decreased rate in ethanol production. An inoculum age between 28-30 h and cell mass content of 0.027-0.036 g/L (dry basis) were used. The results obtained with raw and pretreated bagasse have been compared with those of highly pure Solka Floc (hemicellulose, 10%). Studies on the product inhibition indicated a linear fall of the percent of survivors with time. An Arrhenius type correlation between the cell decay rate constant and the product concentration was predicted. Even at low levels, the inhibitory effects of products on cell viability, the specific growth rate, and extracellular cellulase enzyme were observed.     

Pyrolysis of safflower (Charthamus tinctorius L.) seed press cake: part 1. The effects of pyrolysis parameters on the product yields

Safflower (Charthamus tinctorius L.) seed press cake was pyrolysed in a fixed-bed reactor. The effects of pyrolysis temperature, heating rate and sweep gas flow rates on the yields of the products were investigated. Pyrolysis runs were performed using pyrolysis temperatures between 400 and 600 °C with heating rates of 10, 30 and 50 °C min⁻¹. The obtained bio-char, gas and bio-oil yields ranged between 25 and 34 wt%, 19 and 25 wt%, and 28 and 36 wt%, respectively, at different pyrolysis conditions. The highest liquid yield was obtained at 500 °C pyrolysis temperature with a heating rate of 50 °C min⁻¹ under the sweep gas of N₂ with a flow rate of 100 cm³ min⁻¹. Employing the higher heating rate of 50 °C min⁻¹ results in maximum bio-oil yield, probably due to the decrease in mass transfer limitations. According to the results obtained under the conditions of this study, the effects of pyrolysis temperature and sweep gas flow rate are more significant than the effect of heating rate on the yields.     

Anaerobic fluidized bed whey treatment

Anaerobic treatment of moderate strength lactic casein why permeate [2000-7000 mg/L soluble chemical oxygen demand (SCOD)] is possible in fluidized bed reactors. Removal efficiencies up to 90% were obtained at organic removal rates of 7.7 kg SCOD M(-3) day(-1) and efficiencies of 70% were obtained at organic removal rates of 19.5 kg SCOD M(-3) day(-1), both at 35 degrees C. A removal rate of 3.0 kg SCOD M(-3) day(-1) at 50% removal efficiency was obtained at 15 degrees C. Nutrient requirements were much lower than for CSTR systems, and no supplemental nitrogen or phosphorus was required. Removal rates increased and removal efficiency decreased as the organic loading increased. Microorganism concentration increased with decreasing temperature, compensating for reduced reaction rates at lower temperatures.     

Chemostat cultivation of Candida blankii on sugar cane bagasse hemicellulose hydrolysate

A Candida blankii yeast isolate was grown in sugar cane bagasse hemicellulose hydrolysate at 38 degrees C in carbon-limited chemostat culture. The pretreatment of the acid hydrolysate prior to microbial cultivation consisted of partial neutralization with ammonia and sodium hydroxide, plus the addition of phosphorus, which was the only other growth-limiting nutrient apart from nitrogen. The cell yield coefficient on nitrogen was 16.78. The critical dilution rate was higher (0.35 h(-1)) in diluted hydrolysate than in undiluted hydrolysate (0.21 h(-1)). In undiluted hydrolysate at a dilution rate of 0.1 h(-1) and pH 4, where aseptic procedures proved unnecessary, the cell and protein yield coefficients were 0.53 and 0.26, respectively, and no residual carbon substrates (D-xylose, L-arabinose, D-glucose, and acetic acid) were detected. The cell yield on oxygen increased linearly as a function of dilution rate. The cellular content of protein, carbohydrate, and RNA also increased with an increase in dilution rate, whereas the DNA content decreased slightly. C. blankii has considerable potential for the production of single cell protein from hemicellulose hydrolysate, because of its ability to utilize all of the major carbon substrates in the hydrolysate at a low pH and at a relatively high temperature with a high protein yield. (c) 1992 John Wiley & Sons, Inc.     

Production of activated carbon from bagasse and rice husk by a single-stage chemical activation method at low retention times

The production of activated carbon from bagasse and rice husk by a single-stage chemical activation method in short retention times (30-60min) was examined in this study. The raw materials were subjected to a chemical pretreatment and were fed to the reactor in the form of a paste (75% moisture). Chemicals examined were ZnCl2, NaOH and H3PO4, for temperatures of 600, 700 and 800 degrees C. Of the three chemical reagents under evaluation only ZnCl2 produced activated carbons with high surface areas. BET surface areas for rice husk were up to 750m2/g for 1:1 ZnCl2:rice husk ratio. BET surface areas for bagasse were up to 674m2/g for 0.75:1 ZnCl2:bagasse ratio. Results were compared to regular two-stage physical activation methods.