Preparation and characterization of pyrolytic oil through pyrolysis of neem seed and study of performance,combustion and emission characteristics in CI engine

This paper deals with production of pyrolytic oil from neem seed and using this pyrolytic oil in the form of blend with fossil diesel to study the performance and emission characteristics in CI engine. Thermal and catalytic pyrolysis of non edible neem seed was performed in a slow fixed bed pyrolyser to produce pyrolytic oil. Maximum pyrolytic oil obtained in thermal pyrolysis was 55% wt and in catalytic pyrolysis was 60% wt using both Al₂O₃ and K₂CO₃ catalysts followed by 41% wt and 38% wt for zeolite and kaolin catalysts respectively. The catalytic pyrolysis improved pH and calorific values of 12.4% and 14.4% respectively as compared to thermal pyrolysis. Blends of neem seed catalytic pyrolytic oil (NB) with fossil diesel in the ratio of 5% (NB5) and 10% (NB10) by volume were tested on an unmodified CI engine. Brake thermal efficiency (BTE) was lower at part load conditions and higher at full load condition up to 3.7% in the case of blends as compared to fossil diesel operation. Higher Brake Specific Fuel Consumption (BSFC) was observed in the case of NB5 blend on all load conditions, up to 23.9%. Reduction in emission levels were observed for HC (46.9%), CO (42.2%), CO₂ (29.8%) and NOx (20.7%) at full load condition. This study observed that neem seed catalytic pyrolytic oil is a potential renewable and sustainable green fuel.     

Iron and nitrogen codoped carbon catalyst with excellent stability and methanol tolerance for oxygen reduction reaction

A series of non‐precious metal Fe_xNC electrocatalysts for oxygen reduction reaction (ORR) were successfully synthesized using Fe(NO₃)₃, glucose, and melamine as the Fe, C, and N sources, respectively. The effects of the pyrolysis temperature and Fe/N contents on the catalytic performances are comprehensively investigated. Electrochemical results reveal that among the Fe_xNC catalysts, Fe_1.5NC‐900‐2 pyrolyzed at 900°C with the mass ratio of FeC to melamine being 1:10 proves the highest catalytic performance. The half‐wave potential (E_1/2) of ORR was 821 mV (vs reversible hydrogen electrode (RHE)) and only 36 mV lower than that on commercial Pt/C catalyst (857 mV). More importantly, Fe_1.5NC‐900‐2 catalyst shows excellent stability and methanol tolerance. After 1000 sequential cycles, the E_1/2 on Pt/C catalyst shifts negatively by approximately 60 mV, while for Fe_1.5NC‐900‐2 catalyst, this shift is only 28 mV although the number of sequential cycles is increased to 8000. In the presence of methanol, the current decay in the chronoamperometric response at 1000 seconds is only 8% and also much lower than that on Pt/C catalyst (46%). The high catalytic performances arise from the abundant Fe₃N active sites embedded in the carbon matrix of the Fe_xNC catalysts. These findings can be used to discuss the catalytic mechanism of ORR on the Fe_xNC catalysts and design the nonprecious metal carbon‐based electrocatalysts for ORR.     

Catalytic pyrolysis of LDPE leads to valuable resource recovery and reduction of waste problems

Recycling of waste polymers has become a necessity because huge piles of those polymers represent a threat to the environment. Used polymers are also a source of energy and valuable chemicals.Used low density polyethylenes (LDPE) were catalytically pyrolysed in a home assembled batch reactor under atmospheric pressure. For maximum conversion into chemicals which could be used for feedstock recovery optimum conditions like temperature, catalyst weight and reaction time were optimized. A wide range of acidic and basic catalysts like silica, calcium carbide, alumina, magnesium oxide, zinc oxide and homogeneous mixture of silica and alumina were tried for this purpose.Though CaC₂ was better on the basis of reaction time, however the efficiency of conversion into liquid for SiO₂ was found to be maximum at optimum conditions. These two catalysts could be picked up as suitable catalysts for catalytic pyrolysis of polyethylene. The results of the column separation using different solvents indicate that the oxide containing catalyst could be best suited for selective conversion into polar and aromatic products while CaC₂ catalyst could be adopted for selective conversion into aliphatic products.The liquid product obtained from catalytic pyrolysis was also characterized by physical and chemical tests. Among the physical tests density, specific gravity, API gravity, viscosity, kinematic viscosity, aniline point, flash point, Watson characterization constant, freezing point, diesel index, refractive index, gross calorific value, Net calorific value and ASTM Distillation were determined according to IP and ASTM standard methods for fuel values. From the physical tests it was observed that the results for the liquid fractions are comparable with the standard results of physical tests for gasoline, kerosene and diesel fuel oil. From the Bromine water and KMnO₄ tests it was observed that liquid obtained is a mixture of olefin and aromatic hydrocarbons. This was further confirmed by Bromine number tests. The values of which lie in the range of 0.1–12.8 g/ml, which fall in the range for olefin mixture. Phenol and carbonyl contents were quantified using UV/Visible spectroscopy and the values lie in the range of 1–8920 μg/ml and 5–169 μg/ml for both phenols and carbonyls respectively. The components of different hydrocarbons in the oil mixture were separated by using column chromatography and fractional distillation followed by characterization with FT-IR spectroscopy.The interpretation of FT-IR spectra shows that catalytic pyrolysis of LDPE leads to the formation of a complex mixture of alkanes, alkenes, carbonyl group containing compounds like aldehydes, ketones, aromatic compounds and substituted aromatic compounds like phenols. It could be concluded, that catalytic pyrolysis of LDPE leads to valuable resource recovery and reduction of waste problem.     

Selective catalytic fast pyrolysis of Jatropha curcas residue with metal oxide impregnated activated carbon for upgrading bio-oil

Jatropha curcas waste was subjected to catalytic pyrolysis at 873 K using an analytical pyrolysis–gas chromatography/mass spectrometry in order to investigate the relative effect of various metal oxide/activated carbon (M/AC) catalysts on upgrading bio-oil from fast pyrolysis vapors of Jatropha waste residue. A commercial AC support was impregnated with Ce, Pd, Ru or Ni salts and calcined at 523 K to yield the 5 wt.% M/AC catalysts, which were then evaluated for their catalytic deoxygenation ability and selectivity towards desirable compounds. Without a catalyst, the main vapor products were fatty acids of 60.74% (area of GC/MS chromatogram), while aromatic and aliphatic hydrocarbon compounds were presented at only 11.32%. Catalytic pyrolysis with the AC and the M/AC catalysts reduced the oxygen-containing (including carboxylic acids) products in the pyrolytic vapors from 73.68% (no catalyst) to 1.60–36.25%, with Ce/AC being the most effective catalyst. Increasing the Jatropha waste residue to catalyst (J/C) ratio to 1:10 increased the aromatic and aliphatic hydrocarbon yields in the order of Ce/AC > AC > Pd/AC > Ni/AC, with the highest total hydrocarbon proportion obtained being 86.57%. Thus, these catalysts were effective for deoxygenation of the pyrolysis vapors to form hydrocarbons, with Ce/AC, which promotes aromatics, Pd/AC and Ni/AC as promising catalysts. In addition, only a low yield (0.62–7.80%) of toxic polycyclic aromatic hydrocarbons was obtained in the catalytic fast pyrolysis (highest with AC), which is one advantage of applying these catalysts to the pyrolysis process. The overall performance of these catalysts was acceptable and they can be considered for upgrading bio-oil.     

Promotion of bio oil,H2 gas from the pyrolysis of rice husk assisted with nano silver catalyst and utilization of bio oil blend in CI engine

This paper reports on the pyrolytic distillation of rice husk with catalyst and its influence on both condensable and non-condensable volatiles. The catalyst used for pyrolysis was nano sized silver particles obtained through chemical reduction method. The structural features of the nano silver particles were explored through X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) with Energy-dispersive-X-ray spectroscope (EDX), and the size of the nano particles was confirmed as 90 nm. After intimately mixing the rice husk (30 g) with the catalyst, the pyrolysis at various temperatures (400 °C, 450 °C, 500 °C, 550 °C) was performed. The products obtained during catalytic pyrolysis like gaseous fuel, bio oil, and bio char were separately collected and characterized through Gas Chromatography-Mass Spectrometer (GC-MS) and Inductively Coupled Plasma – Optical Emission Spectrometer (ICP-OES). About 50% of the solid biomass was converted into more useful liquid and gaseous fuel. It was noticed that during catalytic pyrolysis, the quantity of H₂ obtained was more (19.12%) in contrast to thermal pyrolysis and could be attributable to the influence of silver nano particles towards the enhancement in hydrogen gas production. The liquid hydrocarbon obtained during the catalytic distillation was blended with diesel in the ratio 20:80 in the compression ignition (CI) engine. The quality of the blended bio oil was assessed from brake thermal efficiency (BTE), brake specific fuel consumption (BSFC) and emission of nitrogen oxides (NO_X), carbon monoxide (CO) and unburnt hydrocarbon (UHC). At full load, the diesel fuel emitted 1780 ppm of NO_x while the diesel blended with bio oil emitted only 1510 ppm which was 15.17% less than the diesel oil which proved its eco-friendly nature. In future, the bio oil obtained from catalytic pyrolysis can be used as a blend for diesel oil, since it reduces NO_x emission and replaces 20% of diesel oil.     

Catalytic fast pyrolysis of waste pepper stems over HZSM-5

Catalytic fast pyrolysis over HZSM-5 of red pepper stems, a representative agricultural residue material in the southern area of South Korea, was carried out. The SiO₂/Al₂O₃ ratio of the catalyst were 23 and 280. Pyrolysis-gas chromatography/mass spectrometry was used to pyrolyze the pepper stem samples at 550 °C and directly analyze the product distribution. The main product species of the non-catalytic pyrolysis of pepper stems were phenolics, followed by oxygenates and acids. The production of aliphatic and aromatic hydrocarbons was marginal. On the contrary, catalytic pyrolysis over HZSM-5 reduced the fractions of phenolics and acids significantly, while considerably increasing the fractions of aliphatic and aromatic hydrocarbons. The catalytic activity of the HZSM-5 with a SiO₂/Al₂O₃ ratio of 23 was much higher, owing to its much larger amount of strong Brønsted acid sites, than the one with a SiO₂/Al₂O₃ ratio of 280. Conversion of carbohydrate via furans to aromatics over strong acid sites was observed, which was in good agreement with previous studies. This study suggests that the catalytic pyrolysis of lignin-rich biomass over acidic zeolite catalysts can be a promising method to produce valuable chemicals such as aromatic compounds.     

Hydrocarbon gases and oils from the recycling of polystyrene waste by catalytic pyrolysis

The yield and composition of oils and gases derived from the pyrolysis and catalytic pyrolysis of polystyrene has been investigated. The pyrolysis and catalytic pyrolysis was carried out in a fixed bed reactor. Two catalysts were used, zeolite ZSM‐5 and Y‐zeolite and the influence of the temperature of the catalyst, the amount of catalyst loading and the use of a mixture of the two catalysts was investigated. The main product from the uncatalysed pyrolysis of polystyrene was an oil consisting mostly of styrene and other aromatic hydrocarbons. The gases were found to consist of methane, ethane, ethene, propane, propene, butane and butene. In the presence of either catalyst an increase in the yield of gas and decrease in the amount of oil produced was found, but there was significant formation of carbonaceous coke on the catalyst. Increasing the temperature of the Y‐zeolite catalyst and also the amount of catalyst in the catalyst bed resulted in a decrease in the yield of oil and increase in the yield of gas. Copyright © 2004 John Wiley & Sons, Ltd.     

Influence of metal (Fe/Zn) modified ZSM-5 catalysts on product characteristics based on the bench-scale pyrolysis and Py-GC/MS of biomass

In this study, sawdust was selected as the raw material for biomass pyrolysis to obtain organic products. The catalyst was modified with two elements (Fe and Zn). Through analysis of the catalytic products, we attempted to identify a pyrolysis catalyst that can improve the yield of aromatic hydrocarbon products. ZSM-5, modified with Fe and Zn, was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and Brunauer–Emmett–Teller (BET) measurements. Tube furnace and flash pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) were used to comprehensively investigate the characteristics of the products of biomass pyrolysis. The highest yield of phenols was obtained using the Fe-modified ZSM-5 catalyst, which was 18.30% higher than the yield obtained by the pure ZSM-5 catalyst. The lowest yield of acid products was obtained by single-metal-supported catalytic pyrolysis with Fe or Zn, which was 50.66% lower than the yield obtained by direct pyrolysis. During the pyrolysis of biomass using metal-modified catalysts, the production of aromatic hydrocarbons was greatly improved. Among them, compared with direct pyrolysis, the Fe-Zn co-modified ZSM-5 catalyst exhibited the weakest promotion of aromatic hydrocarbon formation, but there was still a 68.50% improvement. Although the co-modified catalyst did not show absolute advantages under the conditions used for this experiment, the improvements in the production of aromatics and phenolic products also showed its potential for improving bio-oil products. Under the action of Fe-modified catalysts, the most abundant components in the gas product were CO and CO₂, which reached levels as high as 53.45% and 15.34%, respectively, showing strong deoxidation capabilities. Therefore, Fe-modified ZSM-5 catalysts were found to better promote the formation of aromatic hydrocarbon products of biomass pyrolysis.     

A novel approach for the liquefaction of wood powder: usage of pyrolytic bio‐oil as a reaction medium

In this study, Scots pine wood (Pinus sylvestris L.) powder was liquefied in the presence of pyrolytic bio‐oil as a reaction medium/reagent. Firstly, the bio‐oil was produced via pyrolysis of the same wood species at three different temperatures by using an extruder type pyrolyzer. Then, the wood powders were liquefied at different ratios of the wood to pyrolytic bio‐oil in a sealed pressure‐proof tube. The liquefaction reactions were carried out under pressure ranging between atmospheric and 8.5‐MPa pressures according to the experimental conditions. The effects of the reactant ratios and the process parameters such as reaction time and temperature on the wood conversion percentage were studied. The chemical composition of the pyrolytic bio‐oil and liquefied wood oil were analyzed by means of GC‐MS technique. The higher heating value (HHV) and UV–Vis spectrophotometric analysis of the pyrolytic bio‐oil and liquefied wood oil were also performed. The results showed that the wood powder could easily be liquefied in the pyrolytic bio‐oil at different temperatures under pressure. The highest wood conversion (97.40%) was obtained at 250 °C for 150 min at a wood to bio‐oil ratio of 1:7 with the heavy fraction of the pyrolytic bio‐oil. The amount of wood residue diminished dramatically when the reaction temperature rose at the same wood to bio‐oil ratio. The HHV of the liquefied wood oil was almost similar to that of the pyrolytic bio‐oil. As a result, it could be inferred that the usage of pyrolytic bio‐oil instead of the phenol and acid catalyst was quite efficient in the wood liquefaction process. Copyright © 2016 John Wiley & Sons, Ltd.     

CO2 gasification characteristics of nascent pyrolyzed particles from coals and oil shale

In this work, the co‐pyrolysis characteristics of oil shale with two typical coals, bitumite and lignite, and the co‐gasification characteristics of the mixture pyrolyzed fuels were studied via thermo‐gravimetric analysis. The individual fuels and mixture fuels were first pyrolysis in N₂ atmosphere to specified temperature (450, 550, and 620 °C) at the heating rate of 20, 30 and 40 °C/min, respectively, and then maintained at the given temperature for 20 min before converted to CO₂ ambient to conduct the CO₂ gasification tests. The kinetic behavior and effects of both fuel types and pyrolysis temperature were investigated. The shoulder peak at around 550 °C observed in the derivative of weight loss derivative thermogravimetry analysis (DTG) curve during the pyrolysis of oil shale has confirmed the existence of specific reactions of oil shale at around 550 °C that leads to a sharp trough in the differential curves of co‐pyrolysis with coals and the unusual change in activation energies of gasification. In isothermal pyrolysis stage, oil shale lost its vast majority of organic matters at the temperature lower than 550 °C. The escape of pyrolysis gas and liquids in the coals is much harder than that in oil shale. The interaction between oil shale and bitumite was too weak to discriminate both in the pyrolysis and CO₂ gasification process. The variation of the particle surface structure caused by the releasing of volatile gases is strongly affected by the reaction rate and temperature. Quick volatile decomposition and gas releasing lead to the increase of surface area, decrease of the average pore diameter as well as the uniformization of the pore structure, while the higher temperature results in the blockade and merging of fine pores. The two factors lead to the greatest mass loss rate in the pyrolyzed particles obtained at 550 °C in temperature programmed CO₂ gasification stage. Two model‐free methods, Friedman method and Flynn–Wall–Ozawa method, were used to extract kinetic parameters from the experimentally determined pyrolyzed fuel conversions. The volatile contend has a significant influence on the fixed carbon conversion during the partially pyrolyzed particles' CO₂ gasification. In this study, significant interactions existed in co‐thermal utilization, both pyrolysis and CO₂ gasification, of oil shale and lignite. It is therefore surmised that co‐gasification of pyrolyzed lignite and oil shale may represent a feasible, practical route to high‐efficiency utilization of these fuels. Copyright © 2017 John Wiley & Sons, Ltd.     

Thermochemical liquefaction characteristics of Cyanobacteria in subcritical and supercritical ethanol–water mixture

The thermochemical liquefaction of Cyanobacteria in subcritical and supercritical ethanol–water mixture was studied with different reaction temperature, reaction time, solvent composition, and solid–liquid ratio. Highest bio‐oil yield of 42.5% containing mainly fatty acid ethyl esters, phenols, pyrrolidinones, and pyridinols was obtained in ethanol–water mixture (4/6, v/v) at temperature of 320°C for 30 min, with solid–liquid ratio of 1 g/15 mL. Both solvent composition and supercritical state had great influence on the liquefaction of Cyanobacteria, while the synergetic effects of water and ethanol in co‐solvents were again verified. Copyright © 2017 John Wiley & Sons, Ltd.     

Influence of calcium promoter on catalytic pyrolysis characteristics of iron-loaded brown coal in a fixed bed reactor

The Fe–Ca catalysts in catalytic pyrolysis of brown coals were studied to investigate the catalytic activity of the Fe–Ca in a fixed-bed reactor. Experimental results showed the maximum yields of the light aromatic hydrocarbons (LAHs) were 5.90 wt% (0.88 wt% of benzene, toluene and xylene ‘BTX’, 4.10 wt% of phenol and cresol ‘PC’ and 0.92 wt% of naphthalene) when the 1.5% Ca was added into 5% Fe-loaded brown coal. The yields of water and gas significantly reduced, the tar yield gradually increased with increasing heating rate. The characterization results indicated that when calcium promoter was impregnated with iron, Ca₂Fe₂O₅, CaO, Fe₂O₃ and α-Fe were formed on the surface of the coal char, Ca₂Fe₂O₅ and α-Fe decomposed polyaromatic tar, CaO and Fe₂O₃ accelerated water gas shift reaction to enhance the H₂ yield, the Fe₂O₃ and Ca₂Fe₂O₅ could be reduced to α-Fe by volatiles (C, CO and H₂) under high temperature catalytic pyrolysis. The synergistic effects between iron and calcium improved brown coal pyrolysis and the volatiles such as free radical fragments were further pyrolyzed, indicating that Fe–Ca catalysts inhibited α-Fe deactivation by tar and carbon deposition, thus promoting brown coal pyrolysis and formation of CO_x, H₂ and LAHs.     

Slow catalytic pyrolysis of rapeseed cake: Product yield and characterization of the pyrolysis liquid

The performance of three catalysts during slow catalytic pyrolysis of rapeseed cake from 150 to 550 °C over a time period of 20 min followed by an isothermal period of 30 min at 550 °C was investigated. Na₂CO₃ was premixed with the rapeseed cake, while γ-Al₂O₃ and HZSM-5 were tested without direct biomass contact. Catalytic experiments resulted in lower liquid and higher gas yields. The total amount of organic compounds in the pyrolysis liquid was considerably reduced by the use of a catalyst and decreased in the following order: non-catalytic test (34.06 wt%) > Na₂CO₃ (27.10 wt%) > HZSM-5 (26.43 wt%) > γ-Al₂O₃ (21.64 wt%). In contrast, the total amount of water was found to increase for the catalytic experiments, indicating that dehydration reactions became more pronounced in presence of a catalyst. All pyrolysis liquids spontaneously separated into two fractions: an oil fraction and aqueous fraction. Catalysts strongly affected the composition and physical properties of the oil fraction of the pyrolysis liquid, making it promising as renewable fuel or fuel additive. Fatty acids, produced by thermal decomposition of the biomass triglycerides, were converted into compounds of several chemical classes (such as nitriles, aromatics and aliphatic hydrocarbons), depending on the type of catalyst. The oil fraction of the pyrolysis liquid with the highest calorific value (36.8 MJ/kg) was obtained for Na₂CO₃, while the highest degree of deoxygenation (14.0 wt%) was found for HZSM-5. The aqueous fraction of the pyrolysis liquid had opportunities as source of added-value chemicals.     

Kinetics of the in−situ hydrogenation of phenol with formic acid as a hydrogen source

Highly active phenolic compounds in biomass pyrolysis oil are an important factor for limiting the utilization of the biofuel. The catalytic hydrogenation of phenolic compounds is considered to be an effective method for reforming bio?oil. Pd/CB (carbon black), which was synthesized by using a facile impregnated method, is found to be an effective catalyst for the in-situ hydrogenation of phenol (a representative model compound of bio?oil) using FA as a hydrogen source to produce cyclohexanone. A 98.99% of the conversion of phenol and 90.20% of the selectivity of cyclohexanone were obtained under the optimized reaction conditions. The catalyst also showed excellent stability after three recycled process. The catalytic kinetics study of the in?situ hydrogenation of phenol was investigated using Power?Rate Law model and Langmuir?Hinshelwood model. The Langmuir?Hinshelwood model fit well to the experimental data and the apparent activation energies (E_a) was 50.96 kJ mol^?1.     

Hydrogen‐rich gas production from catalytic gasification of pine sawdust over Fe‐Ce/olivine catalyst

In order to improve hydrogen production and reduce tar generation during the biomass gasification, a catalyst loaded Fe‐Ce using calcined olivine as the support (Fe‐Ce/olivine catalysts) was prepared through deposition‐precipitation method. The characteristics of catalysts were determined by XRF, BET, XRD, and FTIR. Syngas yield, hydrogen yield, and tar yield were used to evaluate the catalyst activity. Meanwhile, the stability of catalysts was also studied. The results showed that the specific surface area and pore volume of olivine after calcined at high temperature were improved which was beneficial for the load of metals. α‐Fe₂O₃ and CeO₂ were the main active component of Fe‐Ce/olivine catalyst. The Fe‐Ce/olivine catalyst displayed a good performance on the catalytic gasification of pine sawdust with a syngas yield of 0.93 Nm³/kg, H₂ yield of 21.37 mol/kg, and carbon conversion rate of 55.14% at a catalytic temperature and gasification temperature of 800°C. Meanwhile, the Fe‐Ce/olivine catalyst could maintain a good stability after 150 minutes used.     

Comparison of catalytic and noncatalytic pyrolysis and product yields of some waste biomass species

The products obtained by fast pyrolysis of biomass can be used as an energy source or chemical raw material. In this study, samples of hazelnut shells, tea bush, and hazelnut knot selected as waste biomass were from the cities of Trabzon and Rize in the Eastern Black Sea Region. Firstly, the waste biomass samples were granulated into four different particle sizes by milling and sieving operations. Fast pyrolysis of the samples with specific mixing rates was carried out in a fixed bed reactor. Additionally, 2 wt% vanadium (V) oxide (V₂O₅) was used as catalyst to maximize the yield of pyrolysis liquid products. The influence of temperature, heating rate, and particle size on fast pyrolysis yields under both catalytic and noncatalytic conditions were investigated and compared. While the amount of liquid product increased with the addition of catalyst, the amount of solid products decreased. It has been found that the temperature and heating rate parameters are very effective in liquid product yield. In all experiments, the maximum liquid yield was acquired at the same heating rate of 450°C min^?1 and the temperature of 450°C with particle size of 0.5 to 1.0 mm. The maximum pyrolysis liquid (bio‐oil) was obtained with catalytic pyrolysis, and this value was 60.58 wt%.     

Influence of catalyst bed temperature and properties of zeolite catalysts on pyrolysis-catalysis of a simulated mixed plastics sample for the production of upgraded fuels and chemicals

The pyrolysis-catalysis of a simulated mixture of plastics representing the plastic mixture found in municipal solid waste has been carried out to determine the influence of process conditions on the production of upgraded fuel oils and chemicals and gases. The catalysts used were spent zeolite from a fluid catalytic cracker (FCC), Y-zeolite and ZSM-5 zeolite. The addition of a catalyst to the process produced a marked increase in gas yield, with more gas (mainly C₁–C₄ hydrocarbons) being produced as the temperature of the catalyst was raised from 500 °C to 600 °C. The Si/Al ratio of the catalysts influenced the composition of other gases with the more basic catalysts producing more CO and the strongly acidic catalyst producing more H₂. The yield of product oil decreased with the addition of the catalysts, but the oil was of significantly lower molecular weight range, containing a product slate of premium fuel range C₅–C₁₅ hydrocarbons. In addition, the content of aromatic compounds in the product oil was increased; for example, benzene and toluene accounted for more than 90% of the aromatic content of the oil from the strongly acidic Y-zeolite catalysts. A reaction scheme is proposed for the production of single-ring aromatic compounds via pyrolysis-catalysis of plastics.     

Bio‐oil production from rapid pyrolysis of cottonseed cake: product yields and compositions

Fixed‐bed fast pyrolysis experiments have been conducted on a sample of cottonseed cake to determine the effects of pyrolysis temperature, heating rate and sweep gas flow rate on pyrolysis yields and chemical compositions of the product oil. The liquid products and the subfractions of pentane soluble part were characterized by elemental analysis, FT‐IR spectroscopy, ¹H‐NMR spectroscopy and pentane subfraction was analysed by gas chromatography. The maximum oil yield of 34.8% was obtained at final temperature of 550°C with a heating rate of 700°C min^?1 and nitrogen flow rate of 100 cm³ min^?1. Chromatographic and spectroscopic studies on bio‐oil have shown that the oils obtained from cottonseed cake can be used as a renewable fuel and chemical feedstock. Copyright © 2005 John Wiley & Sons, Ltd.     

Rich hydrogen production from crude gas secondary catalytic cracking over Fe/γ-Al2O3

It is generally acknowledged that the continuous production of rich hydrogen is made by using a sequential biomass pyrolysis reactor which combines the pyrolysis of rice husks with the secondary decomposition of gaseous intermediate. Fe/γ-Al₂O₃ catalyst was prepared by incipient wetness impregnation. The result shows that Fe/γ-Al₂O₃ could fully convert biomass pyrolysis volatile into gaseous products, such as H₂、CH₄、CO etc. And the reaction activities of the catalysts are greatly influenced by the calcination temperature of catalysts, the secondary catalytic pyrolysis temperature and Fe/Al mass ratio. The catalyst is characterized by temperature programmed revification (TPR), X-ray diffraction (XRD), scan electron microscope (SEM) and thermogravimetry(TG). The result indicates that the activity centre of Fe/γ-Al₂O₃ is Fe²⁺ and Fe⁰. In brief, the main processes are that large molecule organics in bio-oil decompose into gaseous products, meanwhile the gases are catalytic reformation.     

A comparative study on the quality of bioproducts derived from catalytic pyrolysis of green microalgae Spirulina (Arthrospira) plantensis over transition metals supported on HMS-ZSM5 composite

This study investigated three different types of catalysts: Ni/HMS-ZSM5, Fe/HMS-ZSM5, and Ce/HMS-ZSM5 in the thermochemical decomposition of green microalgae Spirulina (Arthrospira) plantensis. First, non-catalytic pyrolysis tests were conducted in a temperature ranges of 400–700 °C in a dual-bed pyrolysis reactor. The optimum temperature for maximized liquid yield was determined as 500 °C. Then, the influence of acid washing on bio-products upgrading was studied at the optimum temperature. Compared to the product yields from the pyrolysis of raw spirulina, a higher bio-oil yield (from 34.488 to 37.778 %wt.) and a lower bio-char yield (from 37 to 35 %wt.) were observed for pretreated spirulina, indicating that pretreatment promoted the formation of bio-oil, while it inhibited the formation of biochar from biomass pyrolysis. Finally, catalytic pyrolysis experiments of pretreated-spirulina resulted that Fe as an active phase in catalyst exhibited excellent catalytic activity, toward producing hydrocarbons and the highest hydrogen yield (3.81 mmol/gr spirulina).