Biofuel and Bioenergy Technology

He is currently appointed as a Senior Lecturer at the Department of Mechanical Engineering, University of Malaya. In 2018, he also received the Outstanding Research Award and the Most Highly Cited Paper Award at the University of Malaysia Excellence Awards.

Introduction

Statistics of the Special Issue

Published papers are related to the main techniques and analyzes applied to biofuel and bioenergy technology.

Brief Overview of the Contributions to This Special Issue

Optimization of second generation biodiesel production from Australian native stone fruit oil using response surface method. Energies. Numerical Investigation of the Air-Steam Biomass Gasification Process Based on Thermodynamic Equilibrium Model.Energies.

Numerical Investigation of the Air-Steam Biomass Gasiﬁcation Process Based on Thermodynamic

Thermodynamic Equilibrium Model
Model Validation
Results and Discussion
Conclusions

At high ER, the influence of the gasification temperature on the syngas composition is shown in Figure 9. Meanwhile, the predicted GY and the total molar fraction of the combustible gases, based on the tar model, agree better with the experimental data.

Table 1. Operating conditions for the experimental runs of gasiﬁcation.

Experimental Design

Precipitate particles were formed during the early stage of the fermentation of the dairy effluent in the chamber. Electrochemical analysis was performed by the workstation (Jiehan ECW-5600, Taipei, Taiwan) to measure the polarization performance of the Bio-E-Fenton MFCs.

Figure 2. The experimental set-up of the proposed reactor.

Results and Discussions

Nevertheless, the results of Table 3 indicated that a better power performance of the system and COD removal rate in the cathode chamber was observed at a calcination temperature of Fe2O3-500◦C, as it had a suitable pH and DO to be at the to match biocompatibility [42– 44] and electrical conductivity [45,46] in the system. In addition, the average temperature of the anode chamber was controlled at about 35~45◦C (by Bakelite plate) and the cathode temperature was higher than 70◦C (Shown in Table 3), which would be the effect of evaporation.

Table 1. Research studies using Bio-E-Fenton systems.

Conclusions

Enhancing the removal of emerging pollutants using the Fenton reaction driven by H2O2-producing microbial fuel cells. Chem. Analysis of oxygen reduction and microbial community of air-diffusion biocathode in microbial fuel cells. Bioresour.

Effect of Wall Boundary Layer Thickness on Power Performance of a Recirculation Microbial Fuel Cell

Results and Discussion 1. Voltage Output of MFCs

Thus, the thickness of the hydrodynamic boundary layer had no influence on the diffusion of oxygen. The thickness of the velocity boundary layer increased with the flow direction due to the viscosity of the fluid [35,46].

Figure 2. The equivalent circuit of MFC.

Materials and Methods 1. Reactor Construction

Exposure effect of comb-type cathode electrode on sediment microbial fuel cell performance.Appl. Effects of flow rate, inoculation and time on the internal resistance of microbial fuel cells. Bioresour.

Figure 4. The (A) clear side view and (B) experimental setup of recirculation mode MFCs.

Microbial Biodiesel Production by Direct

Transesteriﬁcation of Rhodotorula glutinis Biomass

Ching Kuan, Wei-Chen Kao, Chun-Ling Chen and Chi-Yang Yu *

Materials and Methods 1. Microorganism and Medium

In order to assess the feasibility of direct application of wet biomass, the effects of moisture content on FAME yield were also studied. The FAME yield increased to 18% when the catalyst concentration was 0.5 g/L; highest FAME yield 94%. FAME yield increased with H2SO4 concentration, and the highest FAME yield of 103% was observed at 0.6 M H2SO4.

Using NaOH as catalyst, the FAME yield decreased with an increase in moisture content (Figure 4); the FAME yield was 34% when the biomass contained 70% moisture.

Figure 1. The effect of catalyst concentration on fatty acid methyl ester (FAME) yield

Analysis of Syngas Production from Biogas via the Tri-Reforming Process

Modeling 1. Chemical Reaction

In the following, the TR process performance is investigated using reactant inlet temperature Tinas the primary parameter. Due to the methane oxidation reaction, the maximum temperature occurs in the near entrance region. The variation in reactant composition effect on TR process performance is investigated in the following.

Figure 9 shows the amount of CO2 contained in the biogas effect on the TR process.

Figure 1. Tri-reform process for syngas production using biogas as feedstock.

Liquid Lipase-Catalyzed Esteriﬁcation of Oleic Acid with Methanol for Biodiesel Production in the

Presence of Superabsorbent Polymer: Optimization by Using Response Surface Methodology

Materials and Methods 1. Materials

The reaction was initiated by adding 10% Eversa Transform lipase to reaction mixtures containing methanol and oleic acid in a molar ratio of 3:1 and various amounts of water (0-30%, w/w). A four-level and four-factorial central composite design was used to study the effects of response factors on the response conversion. After the reaction, a sample was taken from the reaction mixture to determine the reaction conversion.

The oil phase was collected for reaction conversion determination and the aqueous phase containing liquid lipase was then mixed with fresh reactants and SAP to start a new reaction.

Results and Discussion

Figure 3 shows the effects of methanol:oleic acid molar ratio and SAP loading on reaction conversion while maintaining temperature and enzyme loading at their central levels. At each temperature, the conversion of the reaction increased significantly when the methanol:oleic acid molar ratio increased. However, the conversion of the reaction decreased with a further increase in the methanol:oleic acid molar ratio.

Figure 5 shows the effects of temperature and enzyme loading on reaction conversion while keeping the methanol:oleic acid molar ratio and SAP loading at their core levels.

Figure 1. Effects of SAP on the esteriﬁcation with varied water content. The reaction was conducted under the following conditions: molar ratio of methanol to oleic acid of 3:1, a temperature of 35 ◦ C, enzyme loading of 10%, in the presence of 5% SAP ( •

Valorization of Waste Wood as a Solid Fuel by Torrefaction

Materials and Methods

The inorganic components of the raw waste wood are indicated with “other” in the table. The weight loss characteristics of waste wood as a function of torrefaction temperature are illustrated in Figure 2. However, the bulk weight loss of the waste wood is in the temperature range of 250–370◦C.

The results showed that there was an increase in the GCV (MJ/kg) of waste wood with the increase in torrefaction temperature and residence time.

Table 1. Properties of waste wood (raw).

Wastewater Treatment and Biogas Recovery Using Anaerobic Membrane Bioreactors (AnMBRs)

Strategies and Achievements

Fundamentals of AnMBR

It was built to treat high strength wastewater (whey) and was named the anaerobic membrane bioreactor system. Since then, research on the feasibility and treatment efficiency of AnMBRs continues, especially on the material type and configurations for treating low, medium and high strength wastewaters [14-17]. A pilot-scale study of municipal wastewater treatment with an external membrane configuration was reported by Huang et al.

The system achieved COD removal efficiency close to 90%, but a slow and linear increase in filtration resistance was observed under critical flux conditions and subsequently resulted in fouling due to solids buildup on the surface of the membrane.

Membrane Performance of Various Wastewater Treatments 1. Industrial Wastewater

COD removal stood at nearly 90%, with no trace of irreversible fouling observed, yet the methane yield was very low and this was mainly attributed to the influence of COD/SO4–S ratio. The average COD removal was 96.7% corresponding to the inﬂuent COD concentration of 460 mg/L and a methane production of 0.21 L CH4/g COD. Remarkably, increasing OLR from 50–60 g COD/L·day by the end of operation yielded a high COD removal efficiency of more than 90%.

Permeate quality was excellent regardless of HRT differences, with greater than 90% COD removal at 6 h HRT.

Effect of Microbial Activity on Anaerobic Membrane Performance

Operational and Performance Parameters 1. Temperature

A fact known to most researchers in the field of anaerobic digestion is that an increase in OLR. Operating parameters such as hydraulic retention time (HRT) and solid retention time (SRT) are two factors that play a vital role in the treatment performance of AnMBR. The improvement in effluent and methane quality was attributed to the extended SRT from 30 days to infinity.

This is because any reduction in SRT can reduce the range of reactions required for stable digestion.

Inhibitors

A very important aspect of AnMBRs is the enabling environment that allows SRT to be completely independent of HRT, regardless of the sludge properties. It is mainly due to the biological breakdown of nitrogenous substances in the form of proteins and urea. 122] reveal an apparent COD removal of 78-96% in a study of the effect of high free ammonia concentrations in synthetic wastewater using the UASB reactor.

A total ammonia nitrogen (TAN) concentration of 2.5 g NL-1 was observed at OLR of 0.8 g propionic acid (HPr)/L·day and 95% of the degraded HPr was converted to methane .

Membrane Fouling

Frequent maintenance, changing the intracellular pH of methanogens, and inhibition of a specific enzyme reaction are some of the many ways suggested to overcome ammonia inhibition. A complete understanding of the effects of ammonia toxicity on methanogenic bacteria is not available, but, in the few studies available with intact cultures, it was found to affect treatment in two ways: (i) inhibition of direct inhibition of methane-producing enzymes from ammonium ion and/or (ii) the hydrophobic nature of ammonia molecules which can passively diffuse into bacterial cells causing proton imbalance [126]. Fouling due to the membrane itself can be attributed to the nature of the material, configuration, hydrophobicity, porosity and pore size of the membrane [8].

136] pointed out that cake layers are not uniformly distributed over the entire surface of all the membrane fibers.

Conclusions

Submerged Anaerobic Membrane Bioreactor (SAMBR) Feasibility for Low Strength Wastewater Treatment. Water Sci. Evaluation of a Mushroom Assisted Anaerobic Membrane Bioreactor (SG-AnMBR) for Municipal Wastewater Treatment. Restore. Removal of selected pharmaceuticals in an anaerobic membrane bioreactor (AnMBR) with/without powdered activated carbon (PAC). Chem.

Effects of the acidogenic biomass on the performance of an anaerobic membrane bioreactor for wastewater treatment.Bioresour.

Biogas Quality across Small-Scale Biogas Plants

A Case of Central Vietnam

The Vietnamese small-scale biogas plants operate against the temperature of the surrounding soil as they are built underground. The questionnaire survey was conducted with the owners of small-scale biogas plants from June to July 2013. Furthermore, Table 4 shows a comprehensive overview of biogas composition of small-scale biogas plants reported by other studies from developing countries.

In conclusion, small-scale biogas plants maintain a stable level of biogas quality throughout their lifetime.

Table 1. Most common feedstock for small-scale biogas plants in selected Asian countries.

Design, Construction, and Testing of a

Gasiﬁer-Speciﬁc Solid Oxide Fuel Cell System

Selection of the Design of SOFC System
Description of the SOFC System
System Modelling
Test Runs with the SOFC System
Future Considerations for Improving the Design
Summary

The SOFC system (Figure 2) consists of two hot boxes: the BoP hot box and the SOFC hot box [28];. Syngas composition used to design the SOFC system was based on the model developed and presented in [22]. As a result, the temperature of flue gases leaving the system (pipe 33) decreased slightly.

Exergy analysis of the diesel pre-reforming solid oxide fuel cell system with anode waste gas recycling in the SchIBZ project.

Figure 1. Flow of the integrated plasma gasiﬁer-gas cleanup-solid oxide fuel cell (SOFC) system.

Prospecting for Oleaginous and Robust Chlorella spp

Materials and Methods

The cultures were mediated by a supply of coal-fired flue gas (obtained from a 2 MW demonstration-scale coal-fired power plant located at KIER, Daejeon, Korea) with a flow rate of 0.6 vvm [23]. The compositions (CO, NO, NO2, SO2, CO2 and O2) of the flue gas supplied to the cultures were analyzed using a portable flue gas analyzer (Vario Plus, MRU, Neckarsulm, Germany). In this study, 30 local strains of Chlorella were evaluated for use in flue gas-mediated biodiesel production.

M082 can be considered a potential strain for the simultaneous use of CO2 from flue gas and organic waste for biodiesel production.

Thermophilic Anaerobic Digestion: Enhanced and Sustainable Methane Production from Co-Digestion

Materials and Methods 1. Feedstock and Inoculum

The TS and VS contents of the three LW (CS, PCG, UBP) were higher than the FW contents, and their VS/TS ratios were between 85% and 95%, making them suitable raw materials for TAD (Table 1) . The concentration of total volatile fatty acid (TVFA) and pH at the end of batch tests (the data represented are the average values of the triplicate bottles. The error bars represent the standard deviation). They attributed nutrient balance as one of the reasons for increased synergism during co-digestion.

Maintaining the pH of the system in the appropriate range (6.5 and 7.6) is required for efficient anaerobic digestion [60].

Table 1. The composition of the anaerobic culture medium.

Enhancing Biochemical Methane Potential and Enrichment of Speciﬁc Electroactive Communities

Materials and Methods 1. Nejayote and Inoculum

Nejayote was stored in a cool box at 4◦C from the maize flour mill to the laboratory, which is in accordance with the Standard Test Method 1060 for sample collection and storage [46]. In the other three reactors (N10), inoculum and 3 g of GAC were added to serum bottles ten days before performing the BMP test. After the BMP test was completed, COD, VFA and redox potential were measured for all tests.

MG-RAST software was used to analyze bacterial and archaeal communities through GREENGENES and RDP II databases [ 51 ].

Results

DIET or IHT occurs in the last step of the anaerobic digestion process, but the addition of GAC promotes DIET instead of IHT in reactors N0 and N10 [45]. As shown in Figure 2, the four main bacterial species in all samples were Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. In S0 and S10 mud, the proportion of Firmicutes was lower, accounting for 26% and 25% of all bacteria, respectively.

Bacteroidetes had the highest percentage in C0 and C10, associated with carbon, reaching 48% in C0 and 43% in C10, while in S it constituted 18% of the microbial community.