Adisak Pattiya

Bio-oil production via fast pyrolysis of biomass residues from cassava plants in a fluidised-bed reactor

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.

Application of silver nanofluid containing oleic acid surfactant in a thermosyphon economizer.

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.

Effect of filter media size, mass flow rate and filtration stage number in a moving-bed granular filter on the yield and properties of bio-oil from fast pyrolysis of biomass.

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.

Influence of a glass wool hot vapour filter on yields and properties of bio-oil derived from rapid pyrolysis of paddy residues.

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.

Pyrolysis of cassava rhizome in a counter-rotating twin screw reactor unit

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 <0.6mm, the use of sand as heat transfer medium, nitrogen flow rate of 4-10 L/min and nitrogen pressure of 1-3 bar were thoroughly examined. It was found that the pyrolysis temperature of 550°C could maximise the bio-oil yield (50 wt.%). The other optimum parameters for maximising the bio-oil yield were the biomass particle size of 0.250-0.425 mm, the nitrogen flow rate of 4 L/min and the nitrogen pressure of 2 bar. The use of the heat transfer medium could increase the bio-oil yield to a certain extent. Moreover, the water content of bio-oil produced with the counter-rotating twin screw reactor was relatively low, whereas the solids content was relatively high, compared to some other reactor configurations.

Thermochemical Characterization of Agricultural Wastes from Thai Cassava Plantations

Abstract Agricultural wastes from Thai cassava plantations are proposed as an important source of energy and their thermochemical properties are determined in this study. These include proximate, ultimate, structural, inorganic matter, heating value, and thermogravimetric analyses. The results show that the agricultural wastes have high volatile contents (78–80%, dry basis) and contain 51% carbon, 7% hydrogen, 41% oxygen, 0.7–1.3% nitrogen, and <0.1% sulphur. Structural analysis reveals that cassava residues are composed of about 36% cellulose, 44% hemicellulose, and 24% lignin. The main inorganic elements found are potassium, phosphorus, and calcium. The lower heating values (LHV) of the biomass are approximately 18 MJkg−1. The results indicate that cassava wastes contain high volatile, very low nitrogen and sulphur, and rather low lignin with a medium heating value, suggesting that a high quality and environmentally benign bio-fuel could be produced via thermochemical conversion processing like fast pyrolysis.

The Influence of Pretreatment Techniques on Ash Content of Cassava Residues

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.

Production of bio-oil from pine sawdust by rapid pyrolysis in a fluidized-bed reactor.

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.

Comparative study of wet and dry torrefaction of corn stalk and the effect on biomass pyrolysis polygeneration

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.

Bio-oil production by fast pyrolysis of cassava residues in a free-fall reactor using liquid media-assisted condensation

ABSTRACT 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 lubricant, and ethanol were tested as the liquid medium. Exposure times varied from 60 to 120 min with biomass feed rates from 100 to 250 g/h. Engine lubricant and ethanol tended to decrease biomass yield while increasing gas yield. Benzene and diesel showed slightly increased biomass yield. With benzene, the bio-oil water content (28%) was insignificantly different from that without using any condensation substance. However, with diesel, the water content increased very slightly; with engine lubricant, it decreased to 25%; and with ethanol, it significantly decreased to 12%. Also, using diesel generated higher heating values (30 MJ/kg).