Methyl esters selectivity of transesterification reaction with homogenous alkaline catalyst to produce biodiesel in batch, plug flow, and continuous stirred tank reactors

Selectivity concept is essential in establishing the best operating conditions for attaining maximum production of the desired product. For complex reaction such as biodiesel fuel synthesis, kinetic studies of transesterification reaction have revealed the mechanism of the reaction and rate constants. The objectives of this research are to develop the kinetic parameters for determination of methyl esters and glycerol selectivity, evaluate the significance of the reverse reaction in transesterification reaction, and examine the influence of reaction characteristics (reaction temperature, methanol to oil molar ratio, and the amount of catalyst) on selectivity. For this study, published reaction rate constants of transesterification reaction were used to develop mathematical expressions for selectivities. In order to examine the base case and reversible transesterification, two calculation schemes (Case 1 and Case 2) were established. An enhanced selectivity was found in the base case of transesterification reaction. The selectivity was greatly improved at optimum reaction temperature (60 C), molar ratio (9 : 1), catalyst concentration (1.5 wt.%), and low free fatty acid feedstock. Further research might explore the application of selectivity for specifying reactor configurations

Methyl esters selectivity of transesterification reaction with homogenous alkaline catalyst to produce biodiesel in batch, plug flow, and continuous stirred tank reactors

Selectivity concept is essential in establishing the best operating conditions for attaining maximum production of the desired product. For complex reaction such as biodiesel fuel synthesis, kinetic studies of transesterification reaction have revealed the mechanism of the reaction and rate constants. The objectives of this research are to develop the kinetic parameters for determination of methyl esters and glycerol selectivity, evaluate the significance of the reverse reaction in transesterification reaction, and examine the influence of reaction characteristics (reaction temperature, methanol to oil molar ratio, and the amount of catalyst) on selectivity. For this study, published reaction rate constants of transesterification reaction were used to develop mathematical expressions for selectivities. In order to examine the base case and reversible transesterification, two calculation schemes (Case 1 and Case 2) were established. An enhanced selectivity was found in the base case of transesterification reaction. The selectivity was greatly improved at optimum reaction temperature (60 C), molar ratio (9 : 1), catalyst concentration (1.5 wt.%), and low free fatty acid feedstock. Further research might explore the application of selectivity for specifying reactor configurations

CO2 removal using amine-functionalized kenaf in pressure swing adsorption system

An agro-based adsorbent from kenaf (Hibiscus cannabinus L.) for CO2 removal was prepared by functionalizing it with amine. Amine functionalization improves the adsorbates–adsorbent interaction through the presence of basic active sites on the adsorbent surfaces. Several amines (MEA, DEA, MDEA, AMP, PEI, DETA, TETA, TEPA, DIPA, PEHA, TEA, and DGA) have been selected for the amine-screening process. The result revealed that adsorption capacity of raw kenaf is only 0.624 mmol/g, whereas TEPA attained the highest CO2 capture capacity (0.914 mmol/g). Further study on the effect of amine loadings was conducted using two types of amine (MEA and TEPA) and it was found that the highest CO2 adsorption capacity for is 2.070 mmol/g for MEA to kenaf ratio of 1:1 and 2.086 mmol/g for TEPA to kenaf ratio of 2:1. The regeneration study also showed that kenaf sorbent can be used for repeated cycle operations. Due to the presence of amine on kenaf, the regeneration values of MEA–kenaf (82.15%) and TEPA–kenaf (75.62%) were lower than the raw kenaf (99.07%)

Harmonic reduction of a single-phase multilevel inverter using genetic algorithm and particle swarm optimization

Inverter play important role in power system especially with it capability on reducing system size and increase efficient. Recent research trend of power electronics system are focusing on multilevel inverter topic in optimization on voltage output, reduce total harmonics distortion, modulation technique and switching configuration. Standalone application multilevel inverter is high focused due to the rise of renewable energy policy all around the world. Hence, this research emphasis on identify best topology of multilevel inverter and optimize it among the diode-clamped, capacitor clamped and cascaded H-bridge multilevel inverter to be used for standalone application in term of total harmonics distortion and voltage boosting capability. The first part of research that is identify best topology multilevel inverter is applying sinusoidal pulse width modulation technique. The result shown cascade H-bridge give the best output in both total harmonics distortion (9.27%) and fundamental component voltage (240 Vrms). The research proceed with optimization with fundamental switching frequency method that is optimized harmonic stepped waveform modulation method. The selective harmonics elimination calculation have adapt with genetic algorithm and particle swarm optimization in order to speed up the calculation. Both bio-inspired algorithm is compared in term of total harmonic distortion and selected harmonics elimination for both equal and unequal sources. In overall result shown both algorithm have high accuracy in solving the non-linear equation. However, genetic algorithm shown better output quality in term of selected harmonics elimination where overall no exceeding 0.4%. Particle swarm optimization shows strength in finding best total harmonics distortion where in 7-level cascaded H-bridge multilevel inverter (m=0.8) show 6.8% only as compared to genetic algorithm. Simulation for 3-level, 5-level and 7-level for each multilevel inverter at different circumferences had been done in this research. The result draw out a conclusion where the possibility of having a filterless high efficient invert can be achieve

THE EFFECT OF COSURFACTANT IN CO2 ABSORPTION IN WATER – IN – OIL EMULSION

Carbon dioxide is one of the main concern in the environment when it comes to energy usage of fuel, even the fuel is coming from natural gas sources. Apart from endangered the environment, carbon dioxide also affects the caloric value of the natural gas itself. The presence of carbon dioxide as contaminants is a nuisance for oil and gas industry as its capability of forming corrosion in pipeline, thus its removal is vital for this industry. The absorption of carbon dioxide in emulsions would be an effective method to prevent corrosion. This study focused on the effects of cosurfactant, complementing 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with surfactant which is sorbitan oleate (SPAN 80), on the stability of water-in-oil (W/O) emulsion. This study also investigates the use of blended amines which are methyldiethanolamine (MDEA)/2-amino-2-methyl-1-propanol (AMP) and MDEA as aqueous phase. A modified rotating disk contactor (RDC) was used in absorption process and gas chromatography (GC) was used to determine the amount of the CO2 absorbed. Analysis of carbon dioxide absorption through emulsion indicates that different cosurfactant may change the absorption mechanism

Selection of classification models from repository of model for water quality dataset

This paper proposes a new technique, Model Selection Technique (MST) for selection andranking of models from the repository of models by combining three performance measures(Acc, TPR and TNR). This technique provides weightage to each performance measure to findthe most suitable model from the repository of models. A number of classification modelshave been generated to classify water quality using the most significant features andclassifiers such as J48, JRip and BayesNet. To validate this technique proposed, the waterquality dataset of Kinta River was used in this research. The results demonstrate that theFunction classifier is the optimal model with the most outstanding accuracy of 97.02%, TPR =0.96 and TNR = 0.98. In conclusion, MST is able to find the most relevant model from therepository of models by using weights in classifying the water quality dataset.Keywords: selection of models; water quality; classification model; models repository

Hydrogen adsorption capacity using modified nickel-kenaf core at different concentrations

In this study, surface chemistry modification of kenaf adsorbent in adsorptive hydrogen storage system was computationally investigated using Brunauer-Emmett-Teller (BET) surface area, thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and elemental dispersion X-ray (EDX) analysis, in which the suitability of the adsorbent was determined with detailed physicochemical characterisation analysis. The method used for surface modification was metal deposition method using Ni(NO3)2 with various concentrations at different levels of pressure (up to 6 bars). Based on this research, modified kenaf with 0.4 M Ni(NO3)2 and 2.559 m2 g-1 adsorbed up to 1.013 mmol g-1 of hydrogen compared to the raw kenaf with only 0.396 mmol g-1 of hydrogen adsorbed in 5 h. Two consecutive cycles of adsorption were carried out to show the delivery performance of hydrogen adsorptive storage. Thus, different adsorption ability between the modified kenaf and raw kenaf shows that Ni-metal on kenaf surface assists in hydrogen adsorption process

Carbon dioxide removal in emulsion liquid membrane containing 2-amino-2-methyl-1-propanol /monoethanolamine

Absorption using aqueous alkanolamine is commonly used in industry to remove the carbon dioxide. However it has several weaknesses such as corrosion problem and low absorption rate. Emulsion liquid membrane is introduced as an alternatives method for CO2 absorption because it can reduce the corrosion problem and the formation water droplets creates large interfacial area for absorption to occur. 2-amino-2-methyl-1-propanol (AMP) and monoethanolamine (MEA) present in the aqueous phase in the form of aqueous droplets, surrounded by the organic solution to form water in oil (w/o) emulsion. In this study, effects of amines ratios and amine quantities, and emulsification time and speed on the ELM stability and CO2 absorption were investigated. The ELM was prepared by homogenizing the aqueous and the organic phases. AMP and MEA were added into sodium hydroxide (NaOH) solution to form aqueous solution, and kerosene and Span-80 were mixed to form the organic solution. The absorption study was carried out in rotating disc contactor (RDC) column. A mixture of 12 v% MEA, 4 v% AMP in 100 ml aqueous solution and 8 v% Span-80 in 100 ml organic phase has high stability and can remove 60% of CO2. The stability of the emulsion remained high even after the absorption. This study proved that ELM has the potential to remove CO2 by using only small amount of amines

The impact of Covid-19 pandemic towards the resilience of small medium enterprises (SMEs) in Malaysia

The Covid-19 pandemic has impacted the entire world dramatically. The unprecedented Covid-19 pandemic has widely impacted on Malaysia's economy, especially towards the small-scale economic activities related to the small medium enterprises (SMEs). Therefore, this paper aims to determine the impact of the Covid-19 pandemic towards the resilience of SMEs in Johor, Malaysia. The research methodology employed a quantitative method through a survey method via questionnaire sampling of 60 owners involved in SMEs operators across the case study. The research finding indicated that the Covid-19 pandemic had a massive influence on the economy of the majority of SMEs operators, especially on their income generations which average losses in revenue of more than 50 percent during the Covid-19 pandemic compared to 2019. This resulted from the shutdown of their business activities to curb the spread of the Covid-19 pandemic. Other findings highlighted that the government's initiatives to address the economic impact of SMEs yet insufficient to sustain business activities and income generations for instance access to financing facilities, product marketing opportunities and others. Therefore, required immediate initiatives should be made by all the stakeholders to reduce the economic impacts among the SMEs

The role of silicon-based nanofillers and polymer crystallization on the breakdown behaviors of polyethylene blend nanocomposites

Good breakdown strength is an important feature for the selection of dielectric materials, especially in high-voltage engineering. Although nanocomposites have been shown to possess many promising dielectric properties, the breakdown strength of nanocomposites is often found to be negatively affected. Recently, imposing nonisothermal crystallization processes on polyethylene blends has been demonstrated to be favorable for breakdown strength improvements of dielectric materials. In an attempt to increase nanocomposites' voltage rating, this work reports on the effects of nonisothermal crystallization (fast, moderate and slow crystallizations) on the structure and dielectric properties of a polyethylene blend (PE) composed of 80% low density polyethylene and 20% high density polyethylene, added with silicon dioxide (SiO2) and silicon nitride (Si3N4) nanofillers. Through breakdown testing, the breakdown performance of Si3N4-based nanocomposites was better than SiO2-based nanocomposites. Since nanofiller dispersion within both nanocomposite systems was comparable, the enhanced breakdown performance of Si3N4-based nanocomposites is attributed to the surface chemistry of Si3N4 containing less hydroxyl groups than SiO2. Furthermore, the breakdown strength of SiO2-based nanocomposites and Si3N4-based nanocomposites improved, with the DC breakdown strength increasing by at least 12% when both the nanocomposites were subjected to moderate crystallization rather than fast and slow crystallizations. This is attributed to changes in the underlying molecular conformation of PE in addition to water-related effects. These results suggest that apart from changes in the nanofiller surface chemistry, changes in the underlying molecular conformation of polymers are also important to improve the breakdown performance of nanocomposites