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Deeply deoxygenated bio-oil with ∼1 wt% oxygen is produced in ex situ catalytic fast pyrolysis applying an unmodified HZSM-5 with good regeneration performance.

Coal bottom ash (CBA) disposed to landfills causes environmental issues. Thus, we used CBA in traditional clay ceramics that had the triple advantage of consuming troublesome waste, adsorbing volatile organics and being decorative indoors, replacing up to 40% by weight of clay with CBA and firing from 700 to 1300 °C. Clay and CBA mixtures were cast, cured at room temperature for 24 h and fired at several temperatures. Firing temperature impacted linear shrinkage, water absorption and fracture toughness, more strongly than CBA mixing proportion. Above 1000 °C, fracture toughness and water absorption resistance was enhanced but shrinkage increased. However, adding CBA lessened the contraction. SEM confirmed complete sintering as clay particles fused as a rigid solid above 1000 °C. X-ray diffraction patterns of ceramics containing CBA showed crystobalite and labradorite, in addition to quartz, due to flux materials in CBA. Leachability tests showed that the CBA ceramics were not ‘toxic’ on the USEPA TCLP regulatory list. Adsorption of gaseous toluene, a representative indoor pollutant, followed a Freundlich model: CBA made the adsorption sites more homogeneous, reduced the interaction mechanisms on the surfaces and thus the Freundlich exponent. Increased CBA increased toluene adsorption by 2–7 times.

Effect of copper (Cu) or cerium (Ce) as promoters for nickel-molybdenum/γ-alumina (NiMo/γ-Al2O3) catalyst on the hydrodeoxygenation (HDO) of guaiacol (GUA), a model oxygenated compound found in a bio-oil derived from woody biomass, was comparatively investigated. The addition of Cu- or Ce-promoters affected the physicochemical properties of the NiMo catalyst. The NiMo catalyst promoted by Cu showed the higher reducibility, whilst the Ce-promoter (2–8 wt% based on γ-Al2O3 content) provided the NiMo catalyst with a higher distribution of active metals and induced a greater difficulty in the reduction under hydrogen (H2) atmosphere. For the HDO of GUA at a mild reaction condition (10 bar initial H2 pressure and 300 °C) in the absence of solvent, the Cu-promoter enhanced the hydrogenation activity of the NiMo catalyst to convert GUA to phenol and methylphenols, one-atomic oxygen species. Whereas, the addition of Ce obviously inhibited the formation of coke on the catalyst surface after a long reaction period (6 h) and gave a higher GUA conversion level with increasing yield of phenols. For the HDO of real bio-oil obtained from the fast pyrolysis of cassava rhizome, the NiMo catalysts promoted by Cu or Ce at 4 wt% based on the γ-Al2O3 content showed a higher performance at eliminating the oxygenated compounds in the bio-oil, reducing the oxygen/carbon (O/C) molar ratio by over seven-fold from 1.75 to 0.24–0.25. Moreover, the gross heating value of the bio-oil was improved from 21.5 to ca. 29.0 MJ/kg after the HDO process. However, the addition of the Cu or Ce promoter did not inhibit coke deposition, possibly due to the acidic properties of the bio-oil that deteriorated the catalyst performance by metal leaching.

We investigated the influence of liquid media-assisted condensation on the bio-oil yield using biomass derived from cassava rhizomes and stalks in a free-fall reactor. Benzene, diesel, engine lubri...

Cassava waste consists mainly of rhizome. Around four million tons of the agro-residue is available annually. It has great potential to be used for energy and power generation. In this work, cassava rhizome was converted into biochar in an alternative carbonizer based on semi-continuous, externally heated, retort type, pyrolysis gas burning concept. The reactor capacity was 35 – 50 kg/h, suitable for local entrepreneurs. Tests with cassava rhizome showed that good quality charcoal can be produced in shorter time with much lower atmospheric pollutants, compared with traditional kilns. The carbonization system was demonstrated to perform well in terms of temperature evolution, biochar yields and characteristics.

Sugarcane residues – leaves (SL) and tops (ST) from Thailand were pyrolysed in a fluidised bed reactor incorporated with a hot filter. The aim was to investigate the effects of reaction temperatures and hot filtration on pyrolysis products. The bio-oils were characterised by water, solids and ash contents, density, heating value, pH, viscosity and stability. The optimum pyrolysis temperatures for SL and ST were 429 °C and 403 °C, which gave maximum bio-oil yields of 52.5 wt% and 59.0 wt%, respectively. Using the hot filter reduced bio-oil yield by 7–8 wt%. However, the filtered bio-oils had better viscosity, solids and ash contents and stability.

Fast pyrolysis of eucalyptus bark using a free-fall reactor integrated with an in-situ alcohol feeding unit was studied to investigate the effects of feeding positions (in-situ and external), alcohol types (ethanol and methanol) and alcohol content (5–30 wt%) on bio-oil yield and properties. The results show that the bio-oil yield decreased with alcohol content from 60 wt% (without alcohol) to 40 wt% with 30 wt% alcohol, whereas the gas yield increased and the char yield remained constant. In-situ addition of alcohol was more effective than external mixing in terms of bio-oil viscosity, stability, water content and pH. Feeding 5 wt% alcohol into the process gave similar or better results than external mixing with 30 wt% alcohol. Nearly 70% of the viscosity and 30% of the water content were reduced with 5 wt% methanol added into the process. The heating value, specific gravity, ash and solids contents were similarly improved by the in-situ and external addition.

Fast pyrolysis of biomass in a fluidised-bed reactor incorporated with a moving-bed granular filter is carried out to investigate the effects of pyrolysis and filter temperatures on product yields and bio-oil properties. The results showed that increasing the pyrolysis temperature reduced organic bio-oil and increased reaction water. When the temperature was increased from 400 to 500 °C, the char decomposed to permanent gas and reaction water. Further increase to 550 °C caused the organics to transform to gas. The proportion of CO2 reduced with pyrolysis temperature, while other gases increased. The increase of the filter media temperature from 350 to 380 °C resulted in the decomposition of char to reaction water. Bio-oil water content increased with both pyrolysis and filter temperatures, whereas opposite trend was found with the viscosity. Increasing the filter temperature could lower the bio-oil solids content. Both temperatures did not affect the bio-oil pH and density.

Sawdust contaminated with mineral oils and solids was pyrolysed in a circulating fluidised bed (CFB) reactor. The objectives are to investigate the influences of pyrolysis temperature (400⿿600 °C) and the contaminants on product yields and properties. The results show that bio-oil reached its maximum yield of 67 wt% at 500 °C and had a lower heating value (LHV) of ⿼30 MJ/kg. At this temperature, the char yield of 18 wt% with an LHV of 18 MJ/kg and the gas yield of 15 wt% with an LHV of 28 MJ/Nm3 were obtained. Increasing the temperature tended to reduce the bio-oil water content and stability, while increasing its LHV and viscosity. The presence of mineral oils increased the organic bio-oil yield by suppressing the reaction water and increased the heating value of the non-condensable gas by nearly 3-fold. Both solid and liquid contaminants increased the bio-oil viscosity and LHV and decreased the char LHV. In addition, GC/MS analysis of bio-oils from contaminated sawdust showed the presence of C12-C44 hydrocarbon components.

Despite its prominent potential, the use of rubber wood (Hevea brasiliensis) for bio-oil production has not been fully investigated. This study reported experimental results of the bio-oil production and upgrading from rubber wood using fast pyrolysis technology. The effects of catalyst nature (vermiculite and dolomite), upgrading temperature and bio-oil/catalyst ratio on the product quality were deeply investigated. The results showed that dolomite was suitable to be used as a catalyst for bio-oil upgrading. At 600 °C and a bio-oil/catalyst ratio of 1:1, the bio-oil yield was maximized, while at 400 °C and a ratio of 1:3, the bio-oil heating value was maximized. Depending on usage purposes, a yield-oriented, heating value-oriented or in-between bio-oil upgrading solution could be considered.

Thailand is a major agro-industrial country with many economic crops including corn. In northern part of the country, harvesting of corn grain generates massive amounts of agricultural waste, including corn cobs, peels, leaves and stalks. Open burning of biomass is a common practice as a low-cost, low-effort means in disposing of crop residues and controlling weeds in the field. It releases large quantities of particulate and gaseous pollutants to the atmosphere. The practice has significantly negative impact on the environment and human health. These corn residues can be utilized for renewable energy. A promising alternative to burning is carbonization. Carbonization or slow pyrolysis is a thermochemical conversion of solid organic materials at elevated temperature in the absence of air or oxygen. Through thermal decomposition processes, a solid product called biochar as well as gaseous and liquid byproducts are generated. The objectives of this work were to demonstrate a practical production of biochar from corn cobs in a modern semi-continuous carbonizer, and to evaluate its performance in terms of reaction temperatures attained, overall processing time, biochar yields and properties. Experiments were carried out in a retort typed, cylindrical drum mounted horizontally. Its dimension was 1.5 m long with inside diameter of 1.05 m. The carbonizer was externally heated by combustion of solid biomass and pyrolysis gas in a grated furnace. It was also equipped with slowly rotating paddle. For each test, about 90-120 kg of corn cobs was fed into the reactor. Temperatures at various locations inside the carbonization chamber were recorded and used as representative for pyrolysis temperature. The end of operation for a certain condition was determined by checking that combustible gas was no longer released and the pyrolysis flame was no longer sustained. The reactor was then unloaded and the resulting biochar was left to cool down to room temperature in a closed container. Subsequently, the solid char products were collected, weighed and sent for analysis. Large amount of corn cobs was successfully converted to good quality biochar in a semi-continuous carbonization reactor system. The system was shown to operate well. Biochar yields of 23 – 33 % were obtained, with the heating value as high as 24 MJ/kg. The process took around 2.5 h at maximum loading. The study showed that valuable solid products can be obtained from corn cobs via slow pyrolysis process.

Wet torrefaction (WT) possesses some advantages over dry torrefaction (DT). In this study, a comparative analysis of torrefied corn stalk from WT and DT was conducted along with an investigation of their pyrolysis properties under optimal conditions for biomass pyrolysis polygeneration. Compared with DT, WT removed 98% of the ash and retained twice the amount of hydrogen. The impacts of DT and WT on the biomass macromolecular structure was also found to be different using two-dimensional perturbation correlation infrared spectroscopy (2D-PCIS). WT preserved the active hydroxyl groups and rearranged the macromolecule structure to allow cellulose to be more ordered, while DT removed these active hydroxyl groups and formed inter-crosslinking structures in macromolecules. Correspondingly, the bio-char yield after WT was lower than DT but the bio-char quality was upgraded due to high ash removal. Furthermore, higher bio-oil yield, higher sugar content, and higher H2 generation, were obtained after WT.

This article reports the experimental results of rapid or fast pyrolysis of pine sawdust in a bench-scale plant equipped mainly with a fluidized-bed reactor and a hot vapor filtration unit. The influence of pyrolysis temperature on product distribution was investigated. In each experiment, the mass balance was established and the chemical and physical characteristics of the products were examined. Fast pyrolysis experiments were conducted at a temperature range of 400–500°C using a biomass particle size of 250–425 µm. Results showed that the optimal reaction temperature for bio-oil production was 462°C. The maximum bio-oil yield was approximately 68.4 wt%. The density of bio-oil was found to be 1.2 g/ml. The lower heating value of the bio-oil was 18.2 MJ/kg, while the pH values of the bio-oil were approximately 2.5. The solids and ash contents of bio-oil were 0.3 and 0.01 wt%, respectively.

Fast pyrolysis of eucalyptus bark was carried out in a free-fall pyrolysis unit at different temperatures ranging from 400 to 550 °C to produce bio-oil, char and gas. The bio-oil produced at optimum temperature was mixed with alcohols with an aim to improve its properties. The results showed that the maximum bio-oil yield of 64.65 wt% on dry biomass basis could be obtained at the pyrolysis temperature of 500 °C. The addition of a small proportion (2.5–10%) of alcohol into the bio-oil could improve its viscosity, stability and heating value. These effects were further enhanced when increasing the alcohol.

This research aims to study the internal flow visualization of a miniature loop thermosyphon for several ratios of the internal diameter of the condenser section to the internal diameter of the evaporator section and temperature. The miniature loop thermosyphon will separate gas and condensed liquid, which flow in opposite directions. This not only prevents flooding and drying out, it also increases heat transfer efficiency. The miniature loop thermosyphon consists of three sections, namely evaporator, adiabatic, and condenser sections. The return liquid channel is connected between the condenser and evaporator to convey the condensed liquid. The miniature loop thermosyphons are designed at three internal diameters of the condenser section to the internal diameters of the evaporator section ratios, which are 1.4, 1.6, and 1.8. The evaporator section consists of a copper tube with an internal diameter of 14 mm and a length of 135 mm. The adiabatic section consists of a glass tube with an internal diameter ...

Fast pyrolysis of cassava rhizome was performed in a bench-scale fluidised-bed reactor unit incorporated with a cross-flow moving-bed granular filter. The objective of this research was to examine several process parameters including the granular size (425–1160 μm) and mass flow rate (0–12 g/min) as well as the number of the filtration stages (1–2 stages) on yields and properties of bio-oil. The results showed that the bio-oil yield decreased from 57.7 wt.% to 42.0–49.2 wt.% when increasing the filter media size, the mass flow rate and the filtration stage number. The effect of the process parameters on various properties of bio-oil is thoroughly discussed. In general, the bio-oil quality in terms of the solids content, ash content, initial viscosity, viscosity change and ageing rate could be enhanced by the hot vapour granular filtration. Therefore, bio-oil of high stability could be produced by the pyrolysis reactor configuration designed in this work.

Cassava residues (cassava stalk and cassava rhizome) were subjected to pretreatment techniques with an aim to reduce their ash content. The effects of biomass size reduction, water washing, water-washing temperature, and acid washing on the ash content of the residues were investigated. The results showed that although most simple method, ash could be removed by biomass size reduction and selection. In washing biomass with water, it was found that both washing time and temperature were major variables affecting the ash content. The ash content decreased with washing time. Increasing the washing temperature to 80°C did not significantly reduce further ash until the washing time was 24 h. In addition, the acid washing was concluded to be the most effective technique for ash removal. The ash contents of the cassava stalk and rhizome were decreased from 5.04% to 1.94% and 4.99% to 2.26%, respectively, after washing with dilute HCl solution for 3 h.

This research is aimed at enhancing the traditional thermosyphon by preventing flooding and drying out from the opposite directions of the vapor and liquid. A miniature loop thermosyphon (MLT) consists of three sections, namely, the evaporator, the adiabatic and condenser sections. The return liquid channel is connected between the condenser and the evaporator to convey the condensed liquid. The MLT has a ratio of internal diameter of the condenser section to internal diameter of the evaporator section (Idc/Ide), which is 1.4. The MLT was made from a copper tube of 15-mm, 19-mm, and 22-mm ID. The filling ratios of the working fluid were 30%, 50%, and 80% of evaporator volume with an inclination angle of 90°. The operating temperatures were 70°C, 80°C, and 90°C with ratios of Ide/Idr of 3, 3.8, and 4.4. The research reports the effect of dimensionless parameters on heat-transfer characteristics, namely, Bo, Pr, We, Fr, Ja, Ku, ρ υ /ρ l, and Ide/Idr. It was found that the Bo, Pr, Ja, Ku, ρ υ /ρ l, and Ide/Idr have no effect on heattransfer characteristics. The We, Fr, and Ku have an effect on the heat-transfer characteristics as with increasing We, Fr, and Ku, the heat-transfer characteristics decrease. The research established another modified Kutateladze number, which can also be used to predict MLT in the vertical position.

Fast pyrolysis of agricultural residues from sugarcane and cassava plantations was carried out in a laboratory-scale free-fall reactor unit. The objectives of this work were to investigate the effects of biomass types and pyroysis conditions, such as reactor temperature, condensation temperature, nitrogen flow rate and run duration, on pyrolysis product distribution, as well as to study the basic properties of the products. The results showed that all of the parameters affected the product distribution. The optimum reactor temperatures for maximising bio-oil yield were in the range of 350–450 °C. About 70 wt% of bio-oil yield could be obtained by pyrolysis of cassava stalk at a reactor temperature of 450 °C and a primary condensation temperature of 10 °C. It was also found that the minimum flow rate of nitrogen for obtaining high bio-oil yield was 1.5 l/min. The product characterisation showed that the bio-oil and char produced from the agricultural residues with the free-fall reactor unit were to a certain extent similar to those produced from different types of biomass with different types of pyrolysis reactor configurations.

This article reports experimental results on fast pyrolysis of agricultural residues from cassava plantations, namely cassava rhizome (CR) and cassava stalk (CS), in a fluidised-bed fast pyrolysis reactor unit incorporated with a hot vapour filter. The objective of this research was to investigate the effects of reaction temperatures, biomass particle size and the use of simple hot vapour filtration on pyrolysis product yields and properties. Results showed that the optimum pyrolysis temperatures for CR and CS were 475 °C and 469 °C, which gave maximum bio-oil yields of 69.1 wt% and 61.4 wt% on dry biomass basis, respectively. The optimum particle size for bio-oil production in this study was 250–425 μm. The use of the hot filter led to a reduction of 6–7 wt% of bio-oil yield. Nevertheless, the filtered bio-oils appeared to have a better quality in terms of initial viscosity, solids content, ash content and stability.

The effect of using silver nanofluid (de ionized water mixed with silver nano and particles less than 100 nm) on the thermal characteristics of a two-phase closed thermosyphon in an operating state was investigated in this research. The thermosyphon was made with copper tubes with 7.5, 11.1 and 25.4 mm ID. The filling ratios of 30%, 50% and 80% by evaporator length and aspect ratios of 5, 10, and 20 with an inclination angle 90°. The operating temperatures were 40 °C, 50 °C and 60 °C. The research reports the effect of dimensionless parameters on heat-transfer characteristics were: L e d i , Bo, Pr, We, Fr, Ja, Co, Nu, Ar, Gr and Ku. It was found that the filling ratio has no effect on the ratio of heat-transfer characteristics in the vertical position, but the properties of the working fluid affected the heat-transfer rate. In addition a correlation for predicting the heat flux for the two-phase closed thermosyphon in the vertical position has been established.

Problem statement: The receiver of parabolic dual trough had been designed and built in order to increase efficiency of solar radiation accumulation by using iron-aluminum sheet as an intermediate in receiving heat and it is the study into how to benefit from solar radiation energy. This research proposed the principle of changing solar radiation to be heating energy by using aluminum sheet made into dual parabolic curve tilted with iron-aluminum sheet which was receiver of radiation reflection. Approach: This dual parabolic curve could be adjusted so that heat obtained from the solar radiation accumulation, which was the focus, could spread around iron-aluminum sheet. In testing of heating by solar energy, the unit would be tilted at 16° to the North-South in order to receive solar radiation and the unit was arranged horizontally. The test was classified into 4 conditions including (1) laying the unit horizontally and un-drive the motor, iron-aluminum sheet would be put in place unmoved in vertical line; (2) laying the unit horizontally and drive motor so that iron-aluminum sheet could be moved upwards and downwards along the vertical line; (3) laying the unit to be tilted at 16° with plane level and un-drive motor and (4) laying the unit to be tilted at 16° with the plane level and drive motor so that iron-aluminum sheet could be moved upwards and downwards along the vertical line. Results: It was found from the test of temperature of iron-aluminum sheet that on the first condition, the highest temperature of iron sheet was 75.2°C and the highest temperature of aluminum was 84.7 °C; on the second condition, the highest temperature of iron sheet was 90.6°C and the highest temperature of aluminum was 97.2°C; on the third condition, the highest temperature of iron sheet was 87.4°C and the highest temperature of aluminum was 93.4°C; on the fourth condition, the highest temperature of iron sheet was 94.5°C and the highest temperature of aluminum was 89.4°C. Therefore, the test of laying the unit to be tilted at 16° with the plane level and driving motor leaded to the high temperature since the perpendicular of light and the spreading of sunlight from dual parabolic curve could cover all area. Conclusion: These results indicate dual parabolic curve could be increased efficiency of solar radiation accumulation by using iron-aluminum sheet as an intermediate in receiving heat.

Problem statement: The objective of this study is to compare the methods for approximating the positions of twist fiber in yarn structures. Computer Aided Design (CAD) is applied using parametric equation, spline curve and NURBS curve. The ideal twist fiber and fiber migration are studied in 3 dimensions. Approach: The fiber positions in yarn structures were measured by trace fiber technique. The twist fiber in rayon yarn with 2.1, 3.0 and 6.0 twist factors was used as examples. The geometrical properties of twist fiber including curvature and torsion were applied in the analysis of all twist fiber examples. Each position was approximated along the length of yarn and then graphical representations of fiber are shown. Results: For ideal twist yarn, using parametric equation gives a smoother or better curve than when using the spline and NURBS curves. However, in the case of fiber migration, continuity of spline and NURBS curves are smoother than that of parametric equation. Conclusion/Recommendations: According to the comparison of the approximation method, parametric equation is most suitable for geometric modeling of ideal twist fiber, whereas the spline and NURBS curves were recommended for approximating the position of migrating fiber.

Cassava rhizome was catalytically pyrolysed at 500 °C using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) in order to investigate the effect of catalysts on bio-oil properties. The catalysts studied were zeolite ZSM-5, two aluminosilicate mesoporous materials Al-MCM-41 and Al-MSU-F, and a proprietary commercial catalyst alumina-stabilised ceria MI-575. The influence of catalysts on pyrolysis products was observed through the yields of aromatic hydrocarbons, phenols, lignin-derived compounds, carbonyls, methanol and acetic acid. Results showed that all the catalysts produced aromatic hydrocarbons and reduced oxygenated lignin derivatives, thus indicating an improvement of bio-oil heating value and viscosity. Among the catalysts, ZSM-5 was the most active to all the changes in pyrolysis products. In addition, all the catalysts with the exception of MI-575 enhanced the formation of acetic acid. This is clearly a disadvantage with respect to the level of pH in the liquid bio-fuel.

A counter-rotating twin screw reactor unit was investigated for its behaviour in the pyrolysis of cassava rhizome biomass. Several parameters such as pyrolysis temperature in the range of 500-700°C, biomass particle size of

This article reports experimental results of rapid or fast pyrolysis of rice straw (RS) and rice husk (RH) in a fluidised-bed reactor unit incorporated with a hot vapour filter. The objective of this research was to investigate the effects of pyrolysis temperatures and the use of glass wool hot vapour filtration on pyrolysis products. The results showed that the optimum pyrolysis temperatures for RS and RH were 405 and 452 °C, which gave maximum bio-oil yields of 54.1 and 57.1 wt.% on dry biomass basis, respectively. The use of the hot filter led to a reduction of 4–7 wt.% bio-oil yield. Nevertheless, the glass wool hot filtered bio-oils appeared to have better quality in terms of initial viscosity, solids content and ash content than the non-filtered ones.

This article reports a recent study on the application of a two-phase closed thermosyphon (TPCT) in a thermosyphon for economizer (TPEC). The TPEC had three sections of equal size; the evaporator, the adiabatic section, and the condenser, of 250 mm × 250 mm × 250 mm (W × L × H). The TPCT was a steel tube of 12.7-mm ID. The filling ratios chosen to study were 30, 50, and 80% with respect to the evaporator length. The volumetric flow rates for the coolant (in the condenser) were 1, 2.5, and 5 l/min. Five working fluids investigated were: water, water-based silver nanofluid with silver concentration 0.5 w/v%, and the nanofluid (NF) mixed with 0.5, 1, and 1.5 w/v% of oleic acid (OA). The operating temperatures were 60, 70, and 80°C. Experimental data showed that the TPEC gave the highest heat flux of about 25 kW/m2 and the highest effectiveness of about 0.3 at a filling ratio of 50%, with the nanofluid containing 1 w/v% of OA. It was further found that the effectiveness of nanofluid and the OA containing nanofluids were superior in effectiveness over water in all experimental conditions came under this study. Moreover, the presence of OA had clearly contributed to raise the effectiveness of the nanofluid.

Biomass residues from cassava plants, namely cassava stalk and cassava rhizome, were pyrolysed in a fluidised-bed reactor for production of bio-oil. The aims of this work were to investigate the yields and properties of pyrolysis products produced from both feedstocks as well as to identify the optimum pyrolysis temperature for obtaining the highest organic bio-oil yields. Results showed that the maximum yields of the liquid bio-oils derived from the stalk and rhizome were 62 wt.% and 65 wt.% on dry basis, respectively. The pyrolysis temperatures that gave highest bio-oil yields for both feedstocks were in the range of 475-510 °C. According to the analysis of the bio-oils properties, the bio-oil derived from cassava rhizome showed better quality than that derived from cassava stalk as the former had lower oxygen content, higher heating value and better storage stability.

Rhizome of cassava plants (Manihot esculenta Crantz) was catalytically pyrolysed at 500 °C using analytical pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) method in order to investigate the relative effect of various catalysts on pyrolysis products. Selected catalysts expected to affect bio-oil properties were used in this study. These include zeolites and related materials (ZSM-5, Al-MCM-41 and Al-MSU-F type), metal oxides (zinc oxide, zirconium (IV) oxide, cerium (IV) oxide and copper chromite) catalysts, proprietary commercial catalysts (Criterion-534 and alumina-stabilised ceria-MI-575) and natural catalysts (slate, char and ashes derived from char and biomass). The pyrolysis product distributions were monitored using models in principal components analysis (PCA) technique. The results showed that the zeolites, proprietary commercial catalysts, copper chromite and biomass-derived ash were selective to the reduction of most oxygenated lignin derivatives. The use of ZSM-5, Criterion-534 and Al-MSU-F catalysts enhanced the formation of aromatic hydrocarbons and phenols. No single catalyst was found to selectively reduce all carbonyl products. Instead, most of the carbonyl compounds containing hydroxyl group were reduced by zeolite and related materials, proprietary catalysts and copper chromite. The PCA model for carboxylic acids showed that zeolite ZSM-5 and Al-MSU-F tend to produce significant amounts of acetic and formic acids.

This article reports experimental results of fast pyrolysis of cassava rhizome (CR), in a fluidised-bed fast pyrolysis reactor unit incorporated with a hot vapour filter. The objective of this research is to investigate the effect of reaction temperatures on pyrolysis products. Bio-oils as the main product were characterised for their basic properties such as water content, solids content, ash content, density, pH, elemental composition and heating value. Results showed that the optimum pyrolysis temperature was 472°C, which gave maximum bio-oil yield of 63.23 wt% on dry biomass basis. The water, solids and ash contents of the bio-oil were 18 wt%, 0.8 wt% and