scholarly journals OPTIMIZING THE PROCESS OF TRANSFORMING COFFEE HUSKS INTO BIOCHAR BY MEANS OF HYDROTHERMAL CARBONIZATION

2018 ◽  
Vol 54 (4B) ◽  
pp. 138
Author(s):  
Tran Thi Hien

The conditions of the hydrothermal carbonization process to produce biochar from coffee husk will be optimized for maximum yield. Besides, response surface methodology (RSM) and central composite face-centered (CCF) method will be used in designing experiments. Also, the optimal value of factors such as temperature, time and biomass: water ratio which can provide a maximum yield of biochar will be worked out using Modde 5.0. As a result, the optimal conditions for maximum yield of biochar was obtained as temperature of 180 oC, 3.5 h and biomass: water ratio of 15 %. It can also be concluded that temperature has greater impact on the transformation of biochar than time and biomass: water ratio.

2019 ◽  
Vol 91 (7) ◽  
pp. 1177-1190
Author(s):  
Maria Margarida Mateus ◽  
Sandro Matos ◽  
Dinis Guerreiro ◽  
Paulo Debiagi ◽  
Daniela Gaspar ◽  
...  

Abstract Almond husk liquefaction can be envisaged as an alternative to fossil sources which are becoming exhausted. Lately, the polyols obtain from the lignocellulosic biomass have been under investigation for the production of sustainable chemicals, fuel, materials or other commodities. Within this context, acid-catalyzed liquefaction of such lignocellulosic biomass has been successfully used to access highly functionalized compounds that can be used to replace those produced from petroleum. Almond shells waste can be considered to be part of the lignocellulosic biomass. Its main constituents of are cellulose, hemicellulose, and lignin. In this assay, the biochemical composition of almond husk was estimated based on atomic mass balances, and at the same time, the pyrolysis outcome was also estimated using a kinetic model using some reference compounds. In order to evaluate the use of almond waste as a substrate for acid-catalyzed liquefaction, the most favorable conditions of the liquefaction process were investigated. To better understand the liquefaction process, response surface methodology, in particular, central composite face-centered factorial design was used to set an array of 17 experiments including three replications at the center point leading to the development of a reaction model for further prediction and optimization of the liquefaction outcome. The effect of temperature (120–150 °C), time (20–200 min) and catalyst amount (0.5–5 wt. %) was investigated and a predictive model established.


Author(s):  
S. Chukwuka Iweka ◽  
K. C. Owuama

Human Life on earth is driven by energy and with the global challenge on best ways to manage waste, there is need to convert organic waste to bioenergy which will help reduce the rate of environmental pollution and over dependence on conventional source of energy. In this investigation maize chaff were inoculated with cow rumen using different concentration ratios (S/I) of 1:1, 1: 1.55, 1:3.5 for 25, 31 and 37 days Retention Time (RT) as design by Central Composite Face Centered Design to optimize the process and predict the best response. The result obtained shows that the mixture ratio of 0.65 (1:1.55) for 31 days gave the optimum yield while 0.65 mixing ratio for 37 days gave the maximum yield at 0.42L under mesophilic (20°C to 45°C) condition. The Flash point of the cummulative maximum yield was -164°C which is really flammable. The model F-value is 95.03, p-values is < 0.0001 which is less than 0.05 and both values indicate model terms are significant. Lack of Fit F-value of 0.43 implies the fitting effect is good. Its R2 value of 0.9855 is very close to 1 which is good. In addition, the biogas products were characterized by FTIR spectroscopy and Gas chromatography–mass spectrometry (GC-MS). The FTIR analyzes showed the presence of Alcohol and was further proven by 69% methane gotten as indicated by the GC-MS. Thus, the result shows high methane yield, flammability and suitability for maize chaff inoculated with cow rumen for energy production.


2021 ◽  
Author(s):  
Kamal Hasani ◽  
Sama Hosseini ◽  
Heliya Gholizadeh ◽  
Abdollah Dargahi ◽  
Mehdi Vosoughi

Abstract The aim of the present study was to evaluate the efficiency of advanced oxidation processes (electrochemical, Fenton and electro-Fenton) in the removal of oxytetracycline using SS316 and SS316/β-PbO2 anodes. This study was performed experimentally on a laboratory scale in a 250 mL reactor. First, experiments were designed for the electrochemical process using a central composite design, and the optimal conditions for the variables pH(3.53), electric current density(3.85mA/cm2), initial concentration of oxytetracycline (20mg/L) and electrolysis time (42.35min) was obtained; then, under these conditions, the efficiency of Fenton process with FeSO4 variable without the presence of electrodes was evaluated, and its optimal value was 0.3 g/L, and then in the presence of optimal values ​​of the above 5 variables, the efficiency of electro-Fenton process with H2O2 changes were investigated and the optimal value of 0.12 was obtained for H2O2. The removal efficiencies of oxytetracycline in electrochemical, Fenton, and electro-Fenton processes were 84.7%, 73.4%, and 98.2%, respectively. Under optimal conditions, the SS316/β-PbO2 anode electrode enhanced the oxytetracycline efficiency by electron-Fenton process to 100%. The results of bioassay with microorganisms showed that the reduction of toxicity of the effluent treated by electro-Fenton process for Pseudomonas aeruginosa and Staphylococcus aureus was 84.5% and 69%, respectively.


2021 ◽  
Vol 11 (12) ◽  
Author(s):  
Lawrence Obidike ◽  
Ezekiel Madigoe

AbstractIn this study, a wastewater treatment program was developed and optimized for the treatment of sewage wastewater. Central composite face design (CCFD) and response surface methodology (RSM) were utilized to develop the experimental design and to establish the relationship between the independent variables (coagulant and flocculant dosage) and responses (turbidity and total dissolved solids removal). Statistical analysis showed that the developed response models were accurate. Optimal removal efficiencies of 93.3% and 23.2% for turbidity and TDS, respectively, were obtained under the optimal conditions for coagulant (120.9 ppm of U6750) and flocculant (125 ppm of Floc887) dosage. This showed that the developed treatment using the coagulant, U6750 and flocculant, Floc887 improved the physical characteristics of the wastewater.


2021 ◽  
Vol 27 (6) ◽  
pp. 210317-0
Author(s):  
Arma Yulisa ◽  
Joonyeob Lee ◽  
Sang Hyeok Park ◽  
Seokhwan Hwang

Electromethanogenesis (EM) is a system that facilitates direct interspecies electron transfer (DIET) in anaerobic digestion (AD) by providing an external power supply to favor desired reactions. Substrates of AD commonly contain ammonia (NH3) as biodegradation product of nitrogen-rich compounds that can deteriorate the stability of AD process. Optimized cathode potential (VCAT) and magnetite (Mag) concentration ([Mag]) are expected to improve AD efficiency in the presence of NH3. Response surface analysis with central composite face-centered design was used in this study to investigate the effect of VCAT and [Mag] under different total ammonia nitrogen concentration ([TAN]). Highest cumulative methane production was achieved at VCAT = -737.4 mV, [Mag] = 18.2 mM, and [TAN] = 1.5 g/L; highest acetate degradation rate was achieved at VCAT = 757.6 mV, [Mag] = 21.4 mM, and [TAN] = 1.5 g/L. The study demonstrated that VCAT promotes either microbial growth or electrochemical NH3 removal. A Shift from acetoclastic to hydrogenotrophic pathway was also observed by the increase of hydrogenotrophic methanogen populations at the end of experiment. This study is beneficial for process control of AD under different NH3 conditions.


2021 ◽  
Vol 346 ◽  
pp. 01044
Author(s):  
Kapil Gupta

Manufacturing of miniature gears with good accuracy and quality, and at low cost is a challenging task for traditional manufacturing processes. Wire-cut electric discharge machining (WEDM) has the capacity to machine any conductive material to fabricate typical shaped products like gears with high level of accuracy and quality. In present research, stainless steel (SS) alloy 316 is used to fabricate miniature gears by WEDM. The experimental array is designed according to Response Surface Methodology (RSM) based central composite face centered (CCFC). Four input parameters namely servo feed (SF), duty factor (DF), servo voltage (SV) and wire feed (WF) with three levels each are used for experimental array to investigate the process performance in terms of cutting rate (CR), and product i.e. gear quality in terms of mean roughness depth (Rz) and dimensional deviation (DD). After WEDM parameter optimization, confirmation experiments are performed at the parametric setting by considering equal importance to all response variables. A very close agreement between the experimental and predicted values have been observed.


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