**Author details**

Razi Ahmad1,4\*, Mohd Azlan Mohd Ishak2,3, Nur Nasulhah Kasim1 and Khudzir Ismail1,3 [11] Ahmad R, Hamidin N, Ali UFM, Abidin CZA. Characterization of bio-oil from palm kernel shell pyrolysis. Journal of Mechanical Engineering Science. 2014;**7**(1):1134-1140

Properties of Torrefied Palm Kernel Shell via Microwave Irradiation

http://dx.doi.org/10.5772/intechopen.81374

45

[12] Ahmad R, Ismail K, Ishak MAM, Kasim NN, Abidin CZA. Pretreatment of palm kernel shell by torrefaction for co-gasification. In: 4th IET Clean Energy and Technology

[13] Chang ACC, Chang H-F, Lin F-J, Lin K-H, Chen C-H. Biomass gasification for hydrogen production. International Journal of Hydrogen Energy. 2011;**36**(21):14252-14260 [14] Howaniec N, Smoliński A. Effect of fuel blend composition on the efficiency of hydrogen-rich gas production in co-gasification of coal and biomass. Fuel. 2014;**128**:442-450 [15] Ahmad R, Azlan M, Ishak M, Kasim NN, Ismail K. Effect of different pretreatments on palm kernel shell and low-rank coal during co-gasification. Progress in Petrochemical

[16] Chen WH, Peng J, Bi XT. A state-of-the-art review of biomass torrefaction, densification and applications. Renewable and Sustainable Energy Reviews. 2015;**44**:847-866

[17] Asadullah M, Adi AM, Suhada N, Malek NH, Saringat MI, Azdarpour A. Optimization of palm kernel shell torrefaction to produce energy densified bio-coal. Energy Conversion

[18] Nam H, Capareda S. Experimental investigation of torrefaction of two agricultural wastes of different composition using RSM (response surface methodology). Energy.

[19] Satpathy SK, Tabil LG, Meda V, Naik SN, Prasad R. Torrefaction of wheat and barley

[20] Mamvura TA, Pahla G, Muzenda E. Torrefaction of waste biomass for application in energy production in South Africa. South African Journal of Chemical Engineering.

[21] Ibrahim RHH, Darvell LI, Jones JM, Williams A. Physicochemical characterisation of torrefied biomass. Journal of Analytical and Applied Pyrolysis. 2013;**103**:21-30

[22] Matali S, Rahman NA, Idris SS, Yaacob N, Alias AB. Lignocellulosic biomass solid fuel properties enhancement via torrefaction. Procedia Engineering. 2016;**148**:671-678 [23] Wang P, Howard BH. Impact of thermal pretreatment temperatures on woody biomass chemical composition, physical properties and microstructure. Energies. 2018;**11**(1):1-20

[24] Salema AA, Ani FN. Microwave-assisted pyrolysis of oil palm shell biomass using an overhead stirrer. Journal of Analytical and Applied Pyrolysis. 2012;**96**:162-172

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\*Address all correspondence to: razi@unimap.edu.my

1 Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia

2 Faculty of Applied Sciences, Universiti Teknologi MARA, Perlis, Malaysia

3 Coal and Biomass Energy Research Group, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia

4 School of Environmental Engineering, Universiti Malaysia Perlis, Arau, Perlis, Malaysia

## **References**


[11] Ahmad R, Hamidin N, Ali UFM, Abidin CZA. Characterization of bio-oil from palm kernel shell pyrolysis. Journal of Mechanical Engineering Science. 2014;**7**(1):1134-1140

**Author details**

44 Biofuels - Challenges and opportunities

Selangor, Malaysia

**References**

Razi Ahmad1,4\*, Mohd Azlan Mohd Ishak2,3, Nur Nasulhah Kasim1

2 Faculty of Applied Sciences, Universiti Teknologi MARA, Perlis, Malaysia

1 Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia

3 Coal and Biomass Energy Research Group, Universiti Teknologi MARA, Shah Alam,

4 School of Environmental Engineering, Universiti Malaysia Perlis, Arau, Perlis, Malaysia

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**Chapter 4**

Provisional chapter

**Chemical Kinetic and High Fidelity Modeling of**

DOI: 10.5772/intechopen.80008

The modeling and simulation of transesterification require an understanding of the chemical reactions that take place inside the reactor. The development of reaction mechanism of the multiple step triglyceride, triglycerides and mono-glycerides and their reversal reaction is beyond the interest of chemical or mechanical engineers, whose main interests are to assess the conversion overall and to establish performance process metrics. This chapter undertakes the transesterification conversion by firstly establishing and formulating the overall process kinetics as far as the rate constant and activation energy. Secondly, use the obtained kinetic values to carry out high fidelity reactive flow of the multiple species which are co-present inside the reactor and otherwise complex to capture experimentally. Following these two steps, this work provides qualitative and quantitative information on the concentration of the reactants, intermediates and the overall yield. This two-stepapproach can also be utilized as reactor design tool and gaining in-depth insight on reaction progress and species distribution. Experimental results, high-fidelity numerical

results, and parametric sensitivity studies will be introduced and discussed. Keywords: chemical kinetic, transesterification, CFD, biodiesel, crude glycerol

Stoichiometrically and theoretically speaking, transesterification consumes 1 mole of triglyceride and 3 moles of alcohol to produce 3 moles of fatty acid methyl esters (FAME) and 1 mole of crude glycerol. Practically, unconverted triglyceride (TG) and intermediates (i.e. diglyceride (DG) and monoglyceride (MG)) co-present in the yield which signifies the incompletion of the reaction [1]. As these reactions are mildly influenced by temperature and pressure because of their nearly equal heat of formation and liquid phase, the increase in the molarity of the alcohol

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Chemical Kinetic and High Fidelity Modeling of

**Transesterification**

Transesterification

Abstract

1. Introduction

Isam Janajreh and Manar Almazrouei

Isam Janajreh and Manar Almazrouei

http://dx.doi.org/10.5772/intechopen.80008

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter


#### **Chemical Kinetic and High Fidelity Modeling of Transesterification** Chemical Kinetic and High Fidelity Modeling of Transesterification

DOI: 10.5772/intechopen.80008

Isam Janajreh and Manar Almazrouei Isam Janajreh and Manar Almazrouei

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.80008

#### Abstract

[27] Pickles CA, Gao F, Kelebek S. Microwave drying of a low-rank sub-bituminous coal.

[28] Kingman SW, Rowson NA. Microwave treatment of minerals—A review. Minerals

[29] Binner E, Lester E, Kingman S, Dodds C, Robinson J. A review of microwave coal processing. The Journal of Microwave Power and Electromagnetic Energy. 2014;**48**(1):35-60

[30] Wang MJ, Huang YF, Chiueh PT, Kuan WH, Lo SL. Microwave-induced torrefaction of

[31] Huang YF, Chen WR, Chiueh PT, Kuan WH, Lo SL. Microwave torrefaction of rice straw

[32] Huang Y, Sung H, Chiueh P, Lo S. Microwave torrefaction of sewage sludge and leucaena. Journal of the Taiwan Institute of Chemical Engineers. 2017;**70**:236-243

[33] Sukiran MA, Abnisa F, Wan Daud WMA, Abu Bakar N, Loh SK. A review of torrefaction of oil palm solid wastes for biofuel production. Energy Conversion and Management.

[34] Vuthaluru HB. Investigations into the pyrolytic behaviour of coal/biomass blends using

[35] Sutcu H. Pyrolysis by thermogravimetric analysis of blends of peat with coals of different characteristics and biomass. Journal of the Chinese Institute of Chemical Engineers.

thermogravimetric analysis. Bioresource Technology. 2004;**92**:187-195

rice husk and sugarcane residues. Energy. 2012;**37**(1):177-184

and pennisetum. Bioresource Technology. 2012;**123**:1-7

Minerals Engineering. 2014;**62**:31-42

46 Biofuels - Challenges and opportunities

Engineering. 1998;**11**(11):1081-1087

2017;**149**:101-120

2007;**38**(3-4):245-249

The modeling and simulation of transesterification require an understanding of the chemical reactions that take place inside the reactor. The development of reaction mechanism of the multiple step triglyceride, triglycerides and mono-glycerides and their reversal reaction is beyond the interest of chemical or mechanical engineers, whose main interests are to assess the conversion overall and to establish performance process metrics. This chapter undertakes the transesterification conversion by firstly establishing and formulating the overall process kinetics as far as the rate constant and activation energy. Secondly, use the obtained kinetic values to carry out high fidelity reactive flow of the multiple species which are co-present inside the reactor and otherwise complex to capture experimentally. Following these two steps, this work provides qualitative and quantitative information on the concentration of the reactants, intermediates and the overall yield. This two-stepapproach can also be utilized as reactor design tool and gaining in-depth insight on reaction progress and species distribution. Experimental results, high-fidelity numerical results, and parametric sensitivity studies will be introduced and discussed.

Keywords: chemical kinetic, transesterification, CFD, biodiesel, crude glycerol

### 1. Introduction

Stoichiometrically and theoretically speaking, transesterification consumes 1 mole of triglyceride and 3 moles of alcohol to produce 3 moles of fatty acid methyl esters (FAME) and 1 mole of crude glycerol. Practically, unconverted triglyceride (TG) and intermediates (i.e. diglyceride (DG) and monoglyceride (MG)) co-present in the yield which signifies the incompletion of the reaction [1]. As these reactions are mildly influenced by temperature and pressure because of their nearly equal heat of formation and liquid phase, the increase in the molarity of the alcohol

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


chapter. However, it is important to state that residential communities are in general in favor of trapping this problematic sewerage source that is responsible for clogging the plumbing systems. Collection also can be facilitated by using drum type or smaller plastic containers provided to the local restaurant, school/university canteens, residential communities as a

Chemical Kinetic and High Fidelity Modeling of Transesterification

http://dx.doi.org/10.5772/intechopen.80008

49

The collected WCO generally requires pretreatment that can be facilitated at a moderate temperature to maintain its liquid and less viscous form. One can use the heat of the summer (45–50C) at which unsaturated and saturated steric fatty acid stays in liquid form, and 10– 20 μm filtration can be used to eliminate any suspended oil solid residuals. Dehydrating of the WCO is also required, during which any water content brought by the processed food into the waste cooking oil is liberated through evaporation. At the laboratory scale, stirring and heating pad at near 110C for several hours can perfect this task. Process methanol and catalyst NaOH or KOH can also be substituted with commercially available grade instead of high purity pharmaceutical grade/Sigma-Aldrich that can also leverage process economically. Once pretreatment of the feedstock is done, the NaOH solid catalyst in the form of small ballets is dissolved into methanol at the stipulated ratio, i.e. 0.5–1% by mass of WCO. This process can be facilitated under moderate heating and a temperature below 60C and stirring forming the meth oxide reactant solution. In the lab, multiple transesterification reaction experiments can be conducted simultaneously under the same temperature and stirring rate to reduce experimental sequence and human error. This can be carried out using a multiple dissolution apparatus such as those provided by Agilent Technologies, featuring 6–12 reactor vessels as depicted in Figure 1 [6]. The caps are tightly fitted and are equipped with direct access ports for sampling without process interruption. They all are also set on thermally controlled wells. The process in these individual small-scale batch reactors resemble those carried out in larger

Figure 1. Dissolution apparatus representing eight multiple 1-L batch reactors and HomeBiodeselKits 500-liter batch

reactor.

privately owned small business, or through municipality.

Table 1. Summary of species properties and molecular weight (MW) [5].

promotes the desired forward reaction [2]. Contrary to well-known hydrocarbon fuels that are characterized by fixed thermodynamic and physical properties, the TG, DG, MG have no fixed chemical formula and neither their thermodynamic properties, such as standard enthalpy or specific heats, nor physical ones like density or viscosity, are consistent throughout the literature [3, 4]. Therefore, material characterization is an essential step in the modeling of the transesterification process. The extent of these properties depends on the complexity and comprehensiveness of the simulation, from a simple incompressible flow that requires only viscosity and density, to a complex non-isothermal flow that requires heat of formation, specific heat, thermal conductivity and their associated diffusions. However, as these properties can be derived following the American Society for Testing and Materials (ASTM) standards, their reactions are more complex. Table 1 summarizes some of the utilized properties for the waste oil, TG, DG, and MG used in the work of Noureddine and Zhu who were amongst the pioneers of quantifying transesterification reaction kinetics [5].

Setting up a reaction mechanism of numerous species or elements and hundreds of reactions, while accounting for reaction radicals, is rather impractical for engineers. The overall reaction can be captured through well controlled conditions and yield assessment procedures that can save the pain of the development or use these reaction mechanisms. This chapter undertakes the conventional transesterification at different process temperatures, highlighting their influence on the yield and their distribution inside the reactor.
