scholarly journals Prospects and Challenges of Microwave-Combined Technology for Biodiesel and Biolubricant Production through a Transesterification: A Review

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 788
Author(s):  
Nur Atiqah Mohamad Aziz ◽  
Robiah Yunus ◽  
Dina Kania ◽  
Hamidah Abd Hamid
Keyword(s):  
Microwave Heating ◽  
Energy Savings ◽  
Electrical Energy ◽  
Product Yield ◽  
Conventional Heating ◽  
Animal Fats ◽  
Microwave Assisted ◽  
Mass Transfer Efficiency ◽  
Homogeneous Electromagnetic Field ◽  
Heating Technology

Biodiesels and biolubricants are synthetic esters produced mainly via a transesterification of other esters from bio-based resources, such as plant-based oils or animal fats. Microwave heating has been used to enhance transesterification reaction by converting an electrical energy into a radiation, becoming part of the internal energy acquired by reactant molecules. This method leads to major energy savings and reduces the reaction time by at least 60% compared to a conventional heating via conduction and convection. However, the application of microwave heating technology alone still suffers from non-homogeneous electromagnetic field distribution, thermally unstable rising temperatures, and insufficient depth of microwave penetration, which reduces the mass transfer efficiency. The strategy of integrating multiple technologies for biodiesel and biolubricant production has gained a great deal of interest in applied chemistry. This review presents an advanced transesterification process that combines microwave heating with other technologies, namely an acoustic cavitation, a vacuum, ionic solvent, and a supercritical/subcritical approach to solve the limitations of the stand-alone microwave-assisted transesterification. The combined technologies allow for the improvement in the overall product yield and energy efficiency. This review provides insights into the broader prospects of microwave heating in the production of bio-based products.

Preparation of WC-TiC-Ni3Al-CaF2 functionally graded self-lubricating tool material by microwave sintering and its cutting performance

2020 ◽  
Vol 39 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Siwen Tang ◽  
Rui Wang ◽  
Pengfei Liu ◽  
Qiulin Niu ◽  
Guoqing Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Microwave Heating ◽  
Cutting Performance ◽  
Conventional Heating ◽  
Hard Alloys ◽  
Dry Cutting ◽  
Temperature Oxidation ◽  
Lubricating Material ◽  
Heating Technology

AbstractWith the concern of the environment, green dry cutting technology is getting more and more attention and self-lubricating tool technology plays an important role in dry cutting. Due to the demand for high temperature performance of tools during dry cutting process, cemented carbide with Ni3Al as the binder phase has received extensive attention due to its excellent high temperature strength and high temperature oxidation resistance. In this paper, WC-TiC-Ni3Al-CaF2 graded self-lubricating material and tools were prepared by microwave heating method, and its microstructure, mechanical properties and cutting performance were studied. Results show that gradient self-lubricating material can be quickly prepared by microwave heating technology, and the strength is equivalent to that of conventional heating technology. CaF2 not only plays a role in self-lubrication, but also refines the grain of the material. A reasonable gradient design can improve the mechanical properties of the material. When the gradient distribution exponent is n1 = 2, the material has high mechanical properties. Cutting experiments show that the WC-TiC-Ni3Al-CaF2 functional gradient self-lubricating tool has better cutting performance than the homogeneous WC-TiC-Ni3Al hard alloys.

Microwave-assisted Al-substituted Tobermorite Synthesis

2000 ◽  
Vol 15 (4) ◽  
pp. 850-853 ◽  
Author(s):  
Michihiro Miyake ◽  
Shigeto Niiya ◽  
Motohide Matsuda
Keyword(s):  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Microwave Heating ◽  
Conventional Heating ◽  
Crystallization Time ◽  
Short Reaction Time ◽  
Microwave Assisted

The effect of microwave heating on the hydrothermal synthesis of Al-substituted tobermorite and the removal characteristics of resulting materials were examined and compared with the effect of conventional heating. The microwave heating reduced the crystallization time of Al-substituted tobermorite—i.e., Al-substituted tobermorite was synthesized within 80 min at around 140 °C—and produced smaller crystallites than the conventional heating. The minute crystallites were found to promote the removal characteristics for Cs+ ions in short reaction time.

scholarly journals Microwave-Assisted Pyrolysis of Biomass Waste: A Mini Review

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1190 ◽  
Author(s):  
Saleem Ethaib ◽  
Rozita Omar ◽  
Siti Mazlina Mustapa Kamal ◽  
Dayang Radiah Awang Biak ◽  
Salah L. Zubaidi
Keyword(s):  
Microwave Heating ◽  
Complex Structure ◽  
Initial Moisture Content ◽  
Raw Material ◽  
Conventional Heating ◽  
Operating Parameters ◽  
High Heating Rate ◽  
Biomass Waste ◽  
Promising Alternative ◽  
Microwave Assisted

The utilization of biomass waste as a raw material for renewable energy is a global concern. Pyrolysis is one of the thermal treatments for biomass wastes that results in the production of liquid, solid and gaseous products. Unfortunately, the complex structure of the biomass materials matrix needs elevated heating to convert these materials into useful products. Microwave heating is a promising alternative to conventional heating approaches. Recently, it has been widely used in pyrolysis due to easy operation and its high heating rate. This review tries to identify the microwave-assisted pyrolysis treatment process fundamentals and discusses various key operating parameters which have an effect on product yield. It was found that several operating parameters govern this process such as microwave power and the degree of temperature, microwave absorber addition and its concentration, initial moisture content, initial sweep gas flow rate/residence time. Moreover, this study highlighted the most attractive products of the microwave pyrolysis process. These products include synthesis gas, bio-char, and bio-oil. The benefits and challenges of microwave heating are discussed.

scholarly journals Application of Microwave in Hydrogen Production from Methane Dry Reforming: Comparison Between the Conventional and Microwave-Assisted Catalytic Reforming on Improving the Energy Efficiency

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 618 ◽  
Author(s):  
Seyyedmajid Sharifvaghefi ◽  
Babak Shirani ◽  
Mladen Eic ◽  
Ying Zheng
Keyword(s):  
Energy Efficiency ◽  
Microwave Heating ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Conventional Heating ◽  
Feed Conversion ◽  
Methane Dry Reforming ◽  
Microwave Assisted ◽  
Reaction Conversion ◽  
Active Metal

The microwave-assisted dry reforming of methane over Ni and Ni–MgO catalysts supported on activated carbon (AC) was studied with respect to reducing reaction energy consumption. In order to optimize the reforming reaction using the microwave setup, an inclusive study was performed on the effect of operating parameters, including the type of catalysts’ active metal and their concentration in the AC support, feed flow rate, and reaction temperature on the reaction conversion and H2/CO selectivity. The methane dry reforming was also carried out using conventional heating and the results were compared to those of microwave heating. The catalysts’ activity was increased under microwave heating and as a result, the feed conversion and hydrogen selectivity were enhanced in comparison to the conventional heating method. In addition, to improve the reactants’ conversion and products’ selectivity, the thermal analysis also clarified the crucial importance of microwave heating in enhancing the energy efficiency of the reaction compared to the conventional heating.

scholarly journals Microwave-Assisted Synthesis of Arylidene Acetophenones

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Sheauly Khatun ◽  
M. Z. H. Khan ◽  
Khodeza Khatun ◽  
M. A. Sattar
Keyword(s):  
Microwave Irradiation ◽  
Microwave Heating ◽  
Spectral Data ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Efficient Synthesis ◽  
H Nmr ◽  
Microwave Assisted

An efficient synthesis of arylidene acetophenones have been achieved by using the microwave heating in comparison to the conventional heating. In this work compound 1-phenyle-3-(4-droxyphenyle)-2-propen-1-one, 1-(4-chlorophenyle)-3-phenyle-2-propen-1-one, and 1-(4-chlorophenyle)-3-(4-hydroxyphenyle)-2-propen-1-one have been synthesized by the condensation reaction between aromatic aldehydes and substituted acetophenones under microwave irradiation. The compounds of aldehydes and acetophenones were used as benzaldehyde, parahydroxybenzaldehyde, acetophenone, and parachloroacetophenone. The result shows that the time taken for the reaction was reduced from the conventional 1-2 hours to 60–120 seconds. The yield of the compounds in the conventional heating was moderate while the highest yield of 90–98% was observed in MWI method. The structure of the compounds was characterized by their IR,1H-NMR spectral data.

THE EFFECT OF CONVENTIONAL AND MICROWAVE HEATING TECHNIQUES ON TRANSESTERIFICATION OF WASTE COOKING OIL TO BIODIESEL

2016 ◽  
Vol 78 (8-3) ◽  
Author(s):  
Mohd Johari Kamaruddin ◽  
Nurulsurusiah Mohamad ◽  
Umi Aisah Asli ◽  
Muhammad Abbas Ahmad Zaini ◽  
Kamarizan Kidam ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Processing Parameters ◽  
Waste Cooking Oil ◽  
Green Technology ◽  
Conventional Heating ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Thermal Heating ◽  
Microwave Assisted ◽  
Cooking Oil

This research is focused on the effect of processing parameters such as molar ratio of sample to solvent (1:3-1:15), catalyst loading (0.5-2.5 wt %), temperature (40-80 °C) and time of reaction (5-180 min) on the transesterification yield of waste cooking oil (WCO) in conventional thermal heating and microwave heating techniques. The analysis carried out revealed that the microwave assisted transesterification produced a comparable yield to conventional heating transesterification with ~5 times faster in heating up the reaction mixture to a reaction temperature and reduced ~90% of the reaction time required. This study concludes that microwave assisted transesterification, which is a green technology, may have great potential in reducing the processing time compared to conventional thermal heating transesterification.

scholarly journals A Microwave-Assisted Boudouard Reaction: A Highly Effective Reduction of the Greenhouse Gas CO2 to Useful CO Feedstock with Semi-Coke

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1507
Author(s):  
Huan Dai ◽  
Hong Zhao ◽  
Siyuan Chen ◽  
Biao Jiang
Keyword(s):  
Carbon Dioxide ◽  
Microwave Heating ◽  
Barium Carbonate ◽  
Fixed Bed ◽  
Potential Method ◽  
Fixed Bed Reactor ◽  
Conventional Heating ◽  
Boudouard Reaction ◽  
Co2 Conversion ◽  
Microwave Assisted

The conversion of CO2 into more synthetically flexible CO is an effective and potential method for CO2 remediation, utilization and carbon emission reduction. In this paper, the reaction of carbon-carbon dioxide (the Boudouard reaction) was performed in a microwave fixed bed reactor using semi-coke (SC) as both the microwave absorber and reactant and was systematically compared with that heated in a conventional thermal field. The effects of the heating source, SC particle size, CO2 flow rate and additives on CO2 conversion and CO output were investigated. By microwave heating (MWH), CO2 conversion reached more than 99% while by conventional heating (CH), the maximum conversion of CO2 was approximately 29% at 900 °C. Meanwhile, for the reaction with 5 wt% barium carbonate added as a promoter, the reaction temperature was significantly reduced to 750 °C with an almost quantitative conversion of CO2. Further kinetic calculations showed that the apparent activation energy of the reaction under microwave heating was 46.3 kJ/mol, which was only one-third of that observed under conventional heating. The microwave-assisted Boudouard reaction with catalytic barium carbonate is a promising method for carbon dioxide utilization.

scholarly journals The Analysis of Parametric Sensitivity Based on Designing and Optimization of a New Microwave Heating System

2017 ◽  
Vol 36 (8) ◽  
pp. 847-853 ◽  
Author(s):  
Hua Chen ◽  
Jin Zhang ◽  
Zebin Fan ◽  
Jinhui Peng ◽  
Shaohua Ju
Keyword(s):  
Microwave Heating ◽  
Heating System ◽  
Absorption Efficiency ◽  
Microwave Energy ◽  
Utilization Efficiency ◽  
Conventional Heating ◽  
Important Index ◽  
Energy Absorption Efficiency ◽  
Matching Performance ◽  
Heating Technology

AbstractMicrowave-assisted heating technology has become a popular alternative to conventional heating technologies because of its many advantages. However, the matching performance of microwave heating system is of particular concern because it provides an important index of the utilization efficiency of microwave energy. In this work, a new microwave heating system is designed by the theory of optical resonator in first. Then the comprehensive analysis of the mutual coupling of high sensitive geometrical and material parameters were investigated based on this new microwave heating system at 2.45 GHz. It is demonstrated that the thickness of materials dramatically influences microwave energy absorption efficiency and should be carefully considered and perhaps given priority. Moreover, it is shown that matching performance is the best when the titanium concentrates thickness at about 0.075 m.

scholarly journals Optimized Methodologies in Asymmetric Organic Synthesis Applying Microwaves

2019 ◽  
Vol 53 (3) ◽  
Author(s):  
Yamir Bandala ◽  
Roberto Melgar-Fernández ◽  
Ramón Guzmán-Mejía ◽  
José Luis Olivares-Romero ◽  
Blanca Rosa Díaz-Sánchez ◽  
...  
Keyword(s):  
Amino Acids ◽  
Microwave Heating ◽  
Organic Synthesis ◽  
Reaction Times ◽  
Environmentally Friendly ◽  
Product Yield ◽  
Chiral Molecules ◽  
Reaction Conditions ◽  
Microwave Assisted ◽  
Reaction Processes

The use of microwave heating is a valuable tool for synthetic chemists. Being able to reduce reaction times and to increase product yield, this methodology offers to organic chemists the potential to optimize reaction processes. Additionally, microwave-assisted reactions provide more environmentally friendly reaction conditions. In this report, we describe results in the optimization of several organic reactions employed in the synthesis of various chiral molecules such as heterocycles, β-amino acids, and β-peptides, among others.

Effect of Flake Pigmentation on the Microwave-Assisted Alkaline Solvolysis of Postconsumer Polyethylene Terephthalate in Primary C1 – C3 Aliphatic Alcohols

2019 ◽  
pp. 1-12
Author(s):  
O. Sanda ◽  
E. O. Ehinmitola ◽  
A. Y. Kolapo ◽  
E. A. Taiwo
Keyword(s):  
Polyethylene Terephthalate ◽  
Product Yield ◽  
Conventional Heating ◽  
Primary Alcohols ◽  
Sodium Hydroxide Concentration ◽  
Microwave Assisted ◽  
Alcohol Response ◽  
Two Parameters ◽  
Central Composite ◽  
Second Order Equations

This study was carried out to examine the alkaline solvolysis of pigmented postconsumer polyethylene terephthalate (PET) in solutions of C1 – C3 primary alcohols via microwave heating. The effect of various process parameters such as flake pigmentation, time and sodium hydroxide concentration on the degree of PET degradation and product yield were studied for each alcohol. Response surface methodology (RSM) was used for predicting the optimal conditions for alkaline solvolysis of PET scrap, with Central Composite Design (CCD) for the two parameters chosen as the experimental design. The data obtained from measurement of properties were fitted as second-order equations. The findings of this study showed that the yield is independent of the pigmentation and that microwave-assisted alkaline solvolysis of pigmented postconsumer PET resulted in higher conversion within a shorter processing time, compared to conventional heating methods with identical products obtained in each case.

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