Papers by Keyword: RSM

Abstract: The potential for biomass as an alternative source of energy is being studied widely. In this study, process flow design is done to analyse the pyrolysis of biomass and its products and how energy can be generated from its products. The energy used per process is calculated and the heat required in the processes were also calculated. The optimization of process parameters for the production of energy from wood biomass via pyrolysis was conducted using the Response Surface Methodology (RS) in the Design Expert 2022 environment using the following range of process parameters: temperature (400-1000°C), vapour residence time (5-30 min) and particle size (0.5-2.0 mm). The feasible combination of process parameters from the design of experiment was validated via physical experimentation having three responses namely: yield of char, yield of biofuel and yield of syngas. The designed experiments and corresponding outcomes produced three predictive models for estimating the yields of char, biofuel and syngas as a function of temperature, vapour residence time and particle size. The results obtained indicated that low temperature favours the formation of biochar while moderate temperature favours the formation of biofuel and the production of syngas is favoured by elevated temperature. The optimal values of process parameters and responses obtained include: temperature (642.271 °C), vapour residence time (6.248 min), particle size (0.603 mm), yield of char (71.9%), yield of biofuel (71.9%) and yield of syngas (76.5%). This study adds to the literature on the pyrolysis process for the conversion of wood biomass to energy. It also contributes to the fields of renewable and sustainable energy generation.Keywords: Biomass, biofuel, char, renewable and sustainable energy, RSM, syngas

Abstract: Heat exchangers are widely recognized as eco-friendly devices that transfer heat between two or more fluids without mixing. Double Pipe Heat Exchangers (DPHE) are used in many industrial applications such as power generation, chemical processing, HVAC, and renewable energy systems. Traditional DPHEs are simple and reliable, however, they often face limitations in heat transfer. Improving the thermal performance of DPHE can significantly enhance the operational efficiency of thermal energy systems. This study presents a novel fin arrangement to the traditional DPHE using different diamond-shaped fins to improve its thermal performance. The thermal and hydraulic properties of DPHE with different diamond-shaped fin configurations are investigated using CFD analysis. The optimization process is carried out using the Response Surface Method (RSM) for optimal diamond-shaped fin design. The results indicate that novel diamond-shaped fins improve thermal performance, particularly at high mass flow rates. The thermal enhancement factor (TEF), overall heat transfer coefficient, and pressure drop are used to evaluate the thermal performance of DPHE. The diamond-shaped fins exhibit a 55% increase in overall heat transfer coefficient compared to conventional DPHE. The TEF for diamond-shaped fin configurations is higher than 1 with a maximum value of 1.63 for DPHE-HF45 depicting a 63% increase in thermal enhancement. The optimization results show that the optimal fin design achieves a desirability of 81.3%, with a pressure drop of 870.726 Pa and an overall heat transfer coefficient of 2199.85 W/m²K at a mass flow rate of 2.711 lit/min.

Abstract: The manufacturing requirements of isotropy, monolithic forming, suppression of welding deformation, high efficiency, and low cost can all be met by the axial closed die rolling (ACDR) forming process when producing a large-sized TC4 titanium alloy shallow-cavity flange-shaped head. This study combines response surface methodology (RSM) with finite element simulation (FEM) to achieve multi-objective optimization by defining four design variables and three response objectives, resulting in the optimal geometric profile and a matching relationship between the optimal organization and performance of the head. The response model was created using the FEM model of the ACDR forming process of the head, and it was optimized using significance analysis and analysis of variance (ANOVA) based on the simulation results. 3D falls and contour plots were used to determine the ideal process parameters for large-size head forming. The head-forming production was completed in accordance with the process parameters, resulting in a perfect and comprehensive head-forging. Additionally, the flow lines were evenly spaced throughout the cavity and easily observable. Every component's microstructure was discovered to be consistent, with grain sizes up to 5-grade. Additionally, there was less than 3% observed variation in the three-way tensile properties.

Abstract: In friction stir welding process, the selection of optimum process parameter is an important step. To make a welding with high quality in all aspects such as defect free and reduced HAZ region, it becomes necessary to choose the parameter in such a way the temperature developed due to heat generation is in optimum level. A study on the effect of process parameters on temperature distribution and HAZ region is performed for dissimilar combination of AA7075 and AA2014. A statistical model based on Box-Behnken RSM is built to study the interaction effect of parameters on temperature distribution and optimization of process parameter is obtained as is Tool Rotational Speed (TRS) – 1400 rpm, Tool Traverse Speed (TTS) – 1.21mm/s and Tool Size Ratio (TSR) – 4. An experiment of FSW is made with K-type thermocouples for optimized parameter of AA7075+AA2014 and temperature reading is then compared with simulation for validation of model. The prediction accuracy is in the range of maximum 98.69% and minimum 92.45%. It was observed that optimum depth location of thermocouples is beyond the half of thickness because of less error attained as 1.31%.

Abstract: The CNC milling process is one of the most valuable traditional machining processes for machining hardened material by using various coated end mill tools. The attention of the current study has been done on end milling of hardened AISI D2 tool steel which is a commonly used tool steel grade in a press machine. The material removal rate is an essential aspect of improving productivity and reducing lead time and production costs. MRR has been considered as a response in this experimental work. A number of experiments were conducted using the design of the experiment via response surface methodology (RSM). MRR was calculated for each machining performance. A mathematical model of MRR was found using response surface methodology.

Abstract: Nanotechnology especially Zero Valent metals is a modern technology for the degradation of extensive ranges of biological wastewater contaminants. Due to their effectiveness, economically and safely properties, this study successfully prepared and characterized nanoZero Valent Iron (nZVI) to be encapsulated into natural alginate biopolymer. The effect of operating parameters was studied at different environmental conditions; pH, dose (g/L), contact time (min), stirring rate (rpm), and BOD concentrations. Adsorption isotherm, kinetic studies, and statistical analysis (Response Surface Methodology (RSM) and Artificial neural networks (ANNs)) were examined to describe the removal behavior. The obtained results indicated that the maximum removal efficiency was 81.2 % for initial BOD concentration 300 mg/L, at pH 7, using wet dose 3g/L, 25min, and stirring rate 200 rpm. Also, adsorption and kinetic data indicated that the adsorption mechanism runs toward the Sips model to approximate the Freundlich model at low concentration and to solve the Freundlich limitation at high concentration with a maximum adsorption capacity of 181mg/g. Kinetic results describe the solid transformation from one phase to another at a constant temperature by approving Avrami model. Finally, RSM results agree with ANNs results that the “Concentration effect” is the most significant variable that controls the removal efficiency.

Abstract: Duplex stainless steel has become one of the fastest-growing materials in the stainless steel family due to pitting resistance, stress-corrosion cracking, the combination of excellent mechanical properties, production features, and the area of applications such as oil and gas, nuclear and thermal power plants, chemical processing industries, saltwater processing industries, and pipeline systems. However, it is more difficult to machine due to its high toughness, low thermal conductivity, and ductility. The experiment has conducted using 2205- Duplex Stainless steel round bar material considering carbide cutting tools using Computer Numerical Control lathe to estimate machining time to address and meet the industrial need. Using Central Composite Designed by using Response Surface Methodology technique develops a second-order mathematical model based on the machining parameters. The Analysis of Variance technique was used to investigate the material's performance characteristics, and the impact of cutting parameters on the work piece was analyzed using the Design Expert-V12 software. Cutting speed is the most crucial determining factor compared to other factors. The Genetic Algorithm is trained and tested in MATLAB to evaluate the best possible solutions. The genetic Algorithm recommends the most outstanding lowest predicted value of 1.2204 mm. The confirmatory analysis shows the experimental values, and their error percentage is within ±2%; these shows indicated predicted values are very close to the Genetic Algorithm results. The conclusions were in good agreement with the experimental machining time values.

Abstract: This study continues and develops approaching of bauxite residue treatment and associated waste for extracting highly valuable metals and scandium recovery by optimizing a hydrometallurgy method for process intensification. Laboratory-scale experiments were conducted in a nitric acid medium on electrostatic precipitator dust (ESPD) received in bauxite sintering. The method includes prior water-leaching of ESPD and subsequent asid leaching experiments at different liquid-to-solid ratios, leaching times and temperatures. The maximum extraction of the scandium was around 76.5 % at pH=0.2. Experimental design based on response surface methodology was used for obtained values optimization. Researches have shown that the optimization of the conditions for the transfer of scandium from red mud to the leaching solution mainly depends on the pH that have to be adjusted in range 0.5-1.7. The pH should not be too low, since Sc does not have time to go into solution in the presence of iron and other elements, as well as too high, because high values lead to re-precipitation of Sc from the filtrate. Complete study for Sc recovery is under progress and is not elaborated here.

Abstract: Esterification reaction of lactic acid with butanol to produce butyl lactate and its optimal conditions were investigated. Cyclohexane was used as entrainer to remove water to promote reaction yield. Catalyst of NaHSO₄ was also used to increase reaction rate. Reaction parameters of butanol/lactic acid ratio, cyclohexane/lactic acid ratio, catalyst amount, and reaction time were optimized using Response Surface Methodology (RSM). Results showed that the butanol/lactic acid ratio was the most significant factor for esterification yield while interactions between butanol/lactic acid ratio and cyclohexane/lactic acid ratio, butanol/lactic acid ratio, and reaction time were less significant. The correlation coefficient between predicted values and experiment values was 0.985. The optimal conditions for the experiment are: ethanol/lactic acid ratio 5:1, cyclohexane/lactic acid ratio 1:1, catalyst loading 1.5%, and incubation period 3 hours. The esterification yield reaches 99.8% under these conditions.

Abstract: The presence of high CO₂ content in natural gas reservoirs is one of the significant threats to the environment. Cryogenic CO₂ capture technology is amongst the emerging technologies used for natural gas purification before customer use. In this research work, the binary CO₂-CH₄ mixture having 75% CO₂ content is studied. Aspen Hysys simulator with Peng Robinson property package is used for the prediction of phase equilibrium data for the binary mixture. The data obtained through the Aspen Hysys simulator is optimized for the S-V two-phase region for maximum CO₂ capture. Response surface methodology is used for the optimization of the predicted data. Optimization of the pressure and temperature conditions is done to obtain maximum CH₄ in the top stream and minimum CO₂ with minimum energy requirement. In this research work, the pressure and temperature ranges selected from the predicted phase equilibrium data for the optimization are 1 to 20 bar and-65 to-150 °C respectively. At atmospheric pressure and-123.50 °C, the desirability value is maximum, which is 0.843. under these conditions, the CO₂ and CH₄ in the top product stream are 1070.72 Kg/hr and 152.04 Kg/hr respectively with an energy requirement of 2.087 GJ/hr.