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Abstract The combination of biomass gasification with fuel cells, especially high temperature Solid Oxide Fuel Cells (SOFCs) promises sustainable and highly efficient (decentralized and modular) energy conversion systems. This review encompasses the components of biomass integrated gasification–SOFC technology including biomass characteristics, the thermochemical conversion in gasifiers and the factors affecting the gasification process, the cleaning technologies for raw producer gas and its conditioning and finally the integration of gasifier with SOFCs. The influence of impurities present in biomass producer gas such as particulates, tar, H 2 S, HCl and alkali compounds based on recent experimental studies and their tolerance limits towards SOFCs are presented. Even though analysis based on the probable tolerance limits of impurities towards SOFCs and a comprehensive overview of the cleaning technologies for producer gas impurities indicate that producer gas cleaning at various temperatures using current technologies to meet SOFC requirements is possible, more experimental studies are still needed to acquire the detailed information on the tolerance limits of impurities for SOFCs. The recent theoretical modeling and experimental studies of biomass integrated gasification–SOFC systems are also presented.

Abstract Integrating flexibly-operated carbon capture and storage (CCS) into the existing power plants has operational benefits for the future low carbon power systems. This paper proposes an improved formulation for flexible operation of carbon capture power plants (CCPPs) within the conventional economic dispatch (ED) problem. The main contribution of this work is the simplification and the practicality of the variables used for the flexible operation control of the facility. The optimal ED problem of thermal power generation portfolio with CCPPs within the mix are computed using a chaos-enhanced Cuckoo Search optimization algorithm. To test the proposed formulations, an IEEE 30 bus test system was used. The impact of varying carbon prices on the system dispatch was investigated. The results reveal the potentiality of decoupling the generation and emission outputs of the thermal power plants.

This paper proposed an improved electromagnetism-like (EML) algorithm to optimize simultaneously the economic and emission dispatch problem considering operational boundaries with carbon tax. A new local search named Dynamic Drift Shift local search (DDSLS) is developed. From the experimental testing, the performance presented by the EML with DDSLS implementation effectiveness shows better quality as the solution obtained outperform the original EML using with and without line local search. The current proposal improved EML with DDSLS manage to perform the searching to obtain the best optimize total generation cost and minimizing the GHG for the load demand 800MW within the plants constrained limits.

The particle size (µm) of coal bottom ash displayed significant effects on the concrete engineering properties. This research aims to assess the improvement of engineering properties of concrete containing CBA (fineness: 75 and 100 µm) known as Mix 75 and Mix 100, and to optimize the percentage of coal bottom ash as supplementary cement materials in concrete. The physicochemical properties of coal bottom ash were analyzed using X-ray fluorescence, X-ray diffraction, particle size distribution (PSD), and a scanning electron microscope. The strength of concrete was determined based on workability and compressive and splitting tensile strengths. The concrete strength improvement was optimized by response surface methodology. The results of the study showed that coal bottom ash was rich in silicates based on the highest peak at 45°. The scanning electron microscope images showed that coal bottom ash has few cenospheres and components of irregular-shaped char particles. The splitting tensile strengths in 28 curing days gradually decreased with an increase in coal bottom ash. The optimal percentage of coal bottom ash in Mix 75 is equivalent to 6% within 45.4 curing days producing 40 MPa of compressive strength. Meanwhile, the optimal percentage of CBA in Mix 100 is equivalent to 12% within 56 curing days producing 50 MPa of compressive strength. The future works needed to extend the experimental observations are the economic analysis and effect of the greenhouse reduction on the usage of CBA in building infrastructure.

The demand for sustainable buildings is driven by increasing energy and water costs, high reduction of carbon emission and pollutions, and the need for social integration. Sustainability requirements in buildings are intensifying the need for building maintenance. However, attempts to increase ‘sustainable maintenance practices’ in residential buildings have not yielded positive results, yet the behavioural components in maintenance are considered to have the potential to increase household sustainable maintenance practices. This study explores the behaviours of homeowners to motivate the demand side in the sustainable supply chain and marketplace. This study based on a cross-sectional survey questionnaire found that 95% of the survey respondents measured that 16 ‘incentives’ would facilitate homeholders’ engagements with sustainable maintenance practices. The Kaiser-Meyer-Olkin measure of sampling adequacy indicated that the strength of the relationships among the variables were very strong (KMO=0.879). Bartlett's test of sphericity, which tests the overall significance of all the correlations within the correlation matrix, was significant X2 (120) = 1057.557, p<0.001). The major incentives that would stimulate homeowners to practice sustainable maintenance are increase in regulations on manufacture and sales of eco-friendly products, the setting of sustainable maintenance standards for the maintenance organisaton/department. The self-belief that the increasing destruction of the environment is a serious threat to sustainability was found to be incentive to engage on sustainable maintenance practices by the homeowners. A conceptual maintenance behavioural model was presented to encourage sustainable maintenance practice among homeowners. With the model it was demonstrated that technical sustainability depends on non-technical sustainability to succeed. This study contributes original information on the need for qualitative aspects in maintenance management market. Facilities managers, maintenance managers and clients could use this information to enhance their maintenance service delivery. The results suggest many complex maintenance behavioural factors could enable householders make sustainability choices. It will provide feedback and feed ward loops to designers. These results may be relevant to the housing market in other countries.

Abstract Recently, biodiesel has been gaining market share against fossil-origin diesel due to its ecological benefits and because it can be directly substituted for traditional diesel oils. However, the high cost of the raw materials required to produce biodiesel make it more expensive than fossil diesel. Therefore, low-priced raw materials, such as waste cooking oil and animal fats, are of interest because they can be used to drive down the cost of biodiesel. We have produced biodiesel from camel fat using a transesterification reaction with methanol in the presence of NaOH. The experimental variables investigated in this study were the temperature (30–75 °C), reaction time (20–160 min), catalyst concentration (0.25–1.5%), and methanol/fat molar ratio (4:1–9:1). A maximum biodiesel yield of 98.6% was obtained. The fuel properties of biodiesel, such as iodine value, saponification value, density, kinematic viscosity, cetane number, flash point, sulfur content, carbon residue, water and sediment, high heating value, refractive index, cloud point, pour point, and distillation characteristics, were measured. The properties were compared with EN 14214 and ASTM 6751 biodiesel standards, and an acceptable level of agreement was obtained.

Agricultural waste such as oil palm empty fruit bunch (EFB) is of environmental concern to Malaysia as one of the world’s largest oil palm producers. Pyrolysis can be used to treat biomass waste due to its flexibility in producing solid, liquid and gas products. This study attempts to characterize EFB for pyrolysis using microwaves as an alternative heating source. EFB taken from a local oil palm mill was subjected to fuel, chemical and dielectric property analysis. The findings revealed that high moisture and 47% oxygen gave low calorific value of 16 MJ/kg. Notably, high water content is an advantage in microwave heating as water is a good microwave absorber, which results in fast drying. Further, a high volatile content at 70% gave the EFB an advantage of high reactivity. A moderate potassium content of 12.8% could also positively affect microwave absorption. The dielectric properties of EFB were observed to be proportional to the moisture content. Furthermore, the microwave penetration depth was found highest at 20% moisture, i.e. 3.5 cm. However, low values of both dielectric constant and loss of dried EFBs would require the addition of microwave absorbers for pyrolysis reaction. The fuel and chemical characteristics of EFB were found comparable to other biomasses, which indicated a good candidate for microwave pyrolysis treatment.

Abstract Despite studies have demonstrated the possibilities of using water in diesel emulsion fuel to reduce the harmful exhaust emission, limited studies are available at present on the effect of emulsified diesel towards metal corrosion. This study therefore aims to investigate the corrosion behaviour of copper exposed to emulsified diesel. Copper immersion tests in diesel, biodiesel and emulsified diesel were carried out for 1200 h at 25 °C. Similar immersion test in emulsified diesel was also carried out for 240 h, 480 h, 720 h, 960 h and 1200 h at 25 °C. Two emulsifiers such as Span 80 and Tween 80 were used to prepare emulsion consisting of 5 vol% of water in diesel. Among the performed analysis were mass loss, surface morphology, elemental composition, surface topography, surface roughness, microscopy, Fourier transform infrared spectroscopy, emulsion characterization, density, viscosity, water content and total acid number. 11.7 times and 4.7 times higher corrosion rate occurred to the copper coupon exposed to emulsified diesel as compared to diesel and biodiesel, respectively. 68% reduction in corrosion rate occurred for the copper exposed to emulsified diesel between 240 h and 1200 h of immersion duration. Up to 3.6 μm and 1.7 μm in pit depth and width, respectively, formed on the copper surface exposed to emulsified diesel for 1200 h at 25 °C. The increased acidity of emulsified diesel by 4.5 times as compared to diesel due to the addition of emulsifiers to form stable water in diesel emulsion is suggested to have caused the increased corrosion rate. Neutralization and/or use of less acidic emulsifier are recommended to reduce the corrosive effect of emulsified diesel. More works on this area are required to establish the compatibility present between emulsified diesel and fuel delivery metals.

Abstract Biodiesel (B2γ-300) derived from second-generation gamma-irradiated Jatropha curcas (JCO2γ-300) was analyzed. HPLC and NMR were used to determine the purity of B2γ-300, and a value of greater than 99.0% was verified. Phorbol ester (PE) composition in B2γ-300 was analyzed by HPLC but could not be detected. Elemental content of nitrogen (N), carbon (C), hydrogen (H), sulfur (S) and oxygen (O) were analyzed by using NCHS. No sulfur content in B2γ-300 could be detected, but N, C, H and O had values of 0.24%, 80.54%, 6.65% and 12.57%, respectively. Overall, it was concluded that the physicochemical properties of B2γ-300 have potential as source of alternative fuels.