Keartisak Sriprateep

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.

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.

Grey-Taguchi method to optimize the percent zinc coating balances edge joints for galvanized steel sheets using metal inert gas pulse brazing process

The objective of this work was to optimize the percent zinc coating balances edge joints of galvanized steel sheets using the metal inert gas pulse brazing process. The Taguchi method and grey relational analysis were used to determine the relationship between the metal inert gas pulse brazing process parameters and percent zinc coating balances edge joints. The metal inert gas pulse brazing process parameters used in this study included wire feed speeds, arc voltages, travel speed, peak currents, and pulse frequency. The characteristics of metal inert gas pulse brazing process that were considered to find response were percent zinc coating balances edge joints on the upper edge joint (PZBEJ1), the lower edge joint (PZBEJ2), and the back sides of the edge joint (PZBEJ3). Analysis of variance was performed to determine the impact of an individual process parameter on the quality parameters. The results showed that the optimal parameters in which grey relational grade increases at the highest level were wire feed speeds at 3.25 m/min, arc voltages at 16 V, travel speeds at 0.9 m/min, peak currents at 425 A, and pulse frequency at 35 Hz. These parameters gave a 74.90% higher response value than those of the initial parameters of metal inert gas pulse brazing process.

CAD/CAE for stress–strain properties of multifilament twisted yarns

A method is presented for modeling the tensile behavior of multifilament twisted yarns. A filament assembly model and a computer-aided design/computer-aided engineering (CAD/CAE) approach are proposed for the tensile analysis. The geometry of the twisted yarn and the nonlinear filament properties were considered. The finite element method (FEM) and large deformation effects were applied for computation of the stress–extension curves. Ideal yarn structures of five layers with different twist angles were simulated to predict the tensile behavior of each filament and each layer. The stress acting on the filaments after yarn extension could be directly analyzed by the FEM. The stress distribution in the filaments showed that the highest stress regions were located at the filament in the center of the yarn and decreased slightly to the yarn surface. The stress–extensions of the filaments were converted to yarn tensile behavior that is shown in terms of the maximum and average stress–extension curves. The results of this prediction model were compared with the stress–strain curves of high-tenacity rayon yarn and the energy method. The maximum stress–extension curves showed very good agreement with experimental results and are more accurate than those obtained by previous methods.

Optimization for Turning Metal Matrix Composites with Multiple Performance Characteristics

In this paper, an optimization technique for turning metal matrix composites (MMCs) is proposed using the Taguchi method with multiple performance characteristics. The orthogonal array, multi-response signal to noise (S/N) ratio and analysis of variance (ANOVA) are employed to study the performance characteristics. The cutting parameters (cutting velocity and feed) and cutting time are optimized with consideration of multiple performance characteristics including tool wear, surface roughness and the power required to perform the machining operation. The results showed that cutting time was the dominant variable on multiple cutting performance characteristics. Confirmation tests of the optimal levels with the initial cutting parameters are carried out in order to illustrate the effectiveness of this method in turning metal matrix composite.

Application of Taguchi Method in the Optimization of Cutting Parameters for Turning Metal Matrix Composite

The objective of this study was to utilize Taguchi methods to optimize surface roughness, tool wear and power required to perform the machining operation in turning metal matrix composites (MMC). The cutting parameters are analyzed under varying cutting speed, feed rates and cutting time. The settings of turning parameters were determined by using Taguchi’s experimental design method. Orthogonal arrays of Taguchi, the signal-to-noise (S/N) ratio, the analysis of variance (ANOVA) are employed to find the optimal levels and to analyze the effect of the turning parameters. Confirmation tests with the optimal levels of machining parameters are carried out in order to illustrate the effectiveness of Taguchi optimization method. The results show that the Taguchi method is suitable to solve the stated problem with minimum number of trials.

CAD/CAE for stress–strain properties of a wide range of multifilament twisted man-made filament yarns:

In a previous paper, the computer aided design (CAD)/computer aided engineering (CAE) approach was presented and compared via the stress–strain curves of high-tenacity rayon yarn and the energy method. The maximum stress–extension curves showed very good agreement with experimental results and were more accurate than the previous methods. In this paper, the CAD/CAE method is considered in relation to multifilament yarn, which is equally applicable to a wide range of man-made filament yarns from nine material types. The results of this prediction model were compared with the stress–strain curves of experimental results and the energy method. The maximum stress–extension curves showed very good agreement with the experimental results except for the high-tenacity Terylene and Fortisan. The reasons for the poor agreement between the experimental and predicted curves are discussed. The breaking points obtained with this method are also compared with experimental results and discussed.

Using multiple performance characteristics to optimize the percent zinc coating balances edge joints of galvanized steel sheets for metal inert gas pulse brazing process

In this article, an optimization technique using the Taguchi method with multiple performance characteristics for the percent zinc coating balances edge joints of galvanized steel sheets for metal inert gas pulse brazing process was proposed. The orthogonal array, multi-response signal-to-noise ratio, and analysis of variance were employed to study the performance characteristics. Five metal inert gas pulse brazing process parameters, namely, wire feed speed, arc voltages, travel speed, peak currents, and pulse frequency, were optimized with considerations of multiple performance characteristics including percent zinc coating balances edge joints. Experimental results were provided to confirm the effectiveness of this approach. The optimum metal inert gas pulse brazing technique conditions were wire feed speed of 3.25 m/min, arc voltages of 18 V, travel speed of 0.8 m/min, peak currents of 425 A, and pulse frequency of 35 Hz. Confirmation tests of the optimal levels with the initial cutting parameters are carried out in order to illustrate the effectiveness of this method in metal inert gas pulse brazing technique for galvanized steel sheets.

Design Optimization of Cutting Parameters when Drilling Metal Matrix Composites

The Taguchi method is used to find the optimal cutting parameters when drilling metal matrix composites (MMCs) with a polycrystalline diamond (PCD) tool. The combined effects of cutting parameters (cutting velocity and feed rate) and cutting time on three performance measures (tool wear (VBmax), the specific cutting pressure (Ks) and hole surface roughness (Ra)) were investigated employing an orthogonal array, signal to noise (S/N) ratio and the analysis of variance (ANOVA). The optimal cutting parameters for each performance measure were obtained, and the main cutting parameters that affect the cutting performance in drilling operations can be found. The relationship between the drilling parameters and the performance measures were determined using multiple linear regressions. Confirmation tests of the optimal levels with the initial machining parameters are carried out in order to illustrate the effectiveness of this approach for drilling MMCs.

Bio-Oil Production from Agricultural Residues in Northeast of Thailand by Fast Pyrolysis Technology

The aim of this research is to design and fabricate the machine for production of bio-oil from agricultural residues in northeast of Thailand. Experiment: to produce the bio-oil from corn-stalk, husk and sawdust with 200 g/hr of capacity, 500°C of reactor temperature, -10°C of condensing unit temperature and testing of the mechanics and chemical property. The results showed that the yield of bio-oil from corn-stalk husk and sawdust are 17.40 18.40 and 22.40, respectively. According to the physical characterisation of the products, it was found that the bio-oil produced in this work showed similar properties to the bio-oil from commercial production. The results found in this research are useful for the development of a larger-scale bio-oil production unit, which is an on-going project at the Faculty of Engineering, Maha Sarakham University.