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Aims and Scope
Editorial Board

1. Analysing the effect of temperature for steam fluidized-bed gasification of biomass with MP-PIC simulation

Janitha C. Bandara, Britt M. E. Moldestad, Marianne S. Eikeland

Faculty of Technology, Department of Natural Sciences and Maritime Sciences, University College of South-Eastern Norway, Kjølnes Ring 56, 3901, Porsgrunn, Norway.

Abstract: Gasification in fluidized beds is an outstanding technology in biomass to energy conversion. The multiphase particle-in-cell modelling has reduced the computational time related to CFD simulations of dense gas-solid systems like fluidized bed gasification. Barracuda VR commercial CFD package was used to analyse the effect of reactor temperature in steam gasification of biomass. The product gas composition, lower heating value and the cold gas efficiency were compared for steam at 873K, 973K and 1073K. The steam-to-biomass ratio was maintained at a constant value of 0.45. The hydrogen content of the product gas changed from 36% to 57% as the temperature was increased from 873K to 1073K whereas the carbon monoxide content changed from 33% to 13%. The lower heating value and the cold gas efficiency changed from 10.4 MJ/kg to 10.1 MJ/kg and 76.6% to 73.2% respectively within the same temperature range. The formation of tar was not modelled and the gas composition showed high sensitivity towards the reactor temperature.

Volume 9, issue 6, 2018, pp.529-542.

2. Co-combustion characteristic of paper mill reject and coal

Yusup Setiawan

Centre for Pulp and Paper (CPP), Jl.Raya Dayeuhkolot No.132 Bandung, Indonesia.

Abstract: The paper mill which use recycled paper as the raw material generate paper mill reject (PMR) in the range of about 5-10%. PMR  has a high calorific value with low ash and sulfur contents, generally. Processing of PMR into pellet forms as boiler fuel to reduce the use of coal or other fossil fuels has not been done, yet. PMR pellets and coal was mixed in the ratio of 5% PMR and 95% coal (C95R5) and 10% PMR and 90% coal (C90R10). PMR, coal, C95R5 and C90R10 were analyzed for proximate (moisture, ash, volatile matter/VM, fixed carbon/FC), and sulfur contents. Gross calorific value (GCV) of materials was also analyzed. Thermo-gravimetric analysis (TGA) and the derivative thermo-gravimetric analysis (DTG) profile were characterized. To know the possibility of slagging potential trend, analysis of ash mineral content and test of ash fussion temperature (AFT) of materials were carried out. Result indicates that addition of 5-10% PMR to coal affects combustion behaviour of materials.  According to base/acid ratio (B/A) and base acid index (BAI) values, and softening temperature (ST) of slagging index, co-combustion of 5% PMR pellet and 95% coal (C95R5) as boiler fuel is still possible without causing indication of slagging tendency.

3. A green university library based on hybrid PV/wind/battery system

Bahtiyar DURSUN¹, Ahmet ALTAY²

1 Department of Electrical and Electronics Engineering, Istanbul Esenyurt University, Istanbul, Turkey.

2 Department of Information and Records Management, Bartın University, Bartın, Turkey.

Abstract: This paper presents a techno-economic analysis of hybrid renewable energy systems (HRES) to supply the electrical load requirements of the Central Library of Kırklareli University located in Kavaklı Campus, Kırklareli, Turkey. The standalone and grid connected HRES (Grid/PV/battery, wind/battery and PV/wind/battery etc.) considered in the analysis were comprised of different combinations of PV modules and wind turbines supplemented with battery storage. Meanwhile, wind and solar energy potential in Kırklareli is fairly appropriate for supplying energy requirements of some places with no high electricity load like libraries. In this study, the HOMER software is used as the assessment tool to determine the optimal configuration of HRES taking total net present cost (NPC) and cost of energy (CoE) into consideration. As a result, it is determined that the optimal system configuration of standalone hybrid system with the lowest total NPC consists of 40kW PV array, 10kW Wind turbine, 20kW power converter and 72 batteries and also that total NPC and CoE of the optimal configuration are estimated to be $228,330, $0.334/kWh, respectively. Similarly, it is determined that the optimal system configuration of grid connected hybrid system with the lowest total NPC consists of 30kW Wind turbine, 100kW Grid and also that total NPC and CoE of the optimal configuration are estimated to be $137,979, $0.185/kWh, respectively. When these configurations are compared considering CoE and total NPC it is clearly shown that Grid connected hybrid systems is more economical than standalone hybrid system. But some environmental effects (CO₂, CO NOx and carbon tax etc.) are taken into consideration the standalone hybrid system must be preferred.

4. Semi-analytic solution for stability and free vibration of functionally graded (FG) material micro-pipe conveying fluid

Talib EH. Elaikh, Nada M. Abed

Department of Mechanical Engineering, College of Engineering, Thi-Qar University, Iraq.

Abstract: A Micro-scale pipe conveying fluid and the functionally graded (FG) materials have many potential applications. In this article, an analytical solution is offered free vibration for a functionally graded (FG) material micro-pipe conveying fluid. On the basis of the Euler beam model and the modified coupled stress theory. The properties of the material are changed constantly across the micro-pipes thickness and depend on power law distribution. Utilized Hamilton’s principle to get an equation of motion for three end boundary conditions (Simply supported, clamped-clamped and cantilever micro-pipes).The differential transformation (DT) method is utilized to obtain the solution for motion's equation and concerned boundary conditions. The effect of fluid flow velocity, the gradient index and parameter of the material length scale on the vibration and stability of fluid conveying FGM micro scale pipes are discussed. The results show that critical velocities and natural frequencies are increased hastily with the increase in the gradient index p.

5. Optimization thickness of head type for horizontal LPG pressure vessels according to ASME

Marwan Abdulrazzaq Salman¹, Mahmud Rasheed Ismail², Yassr Y.Kahtan²

1 Mechanical Engineerig Department, Al-Nahrain University, Baghdad, Iraq.

2 Prosthetics and orthotics Engineerig Department, Al-Nahrain University, Baghdad, Iraq.

Abstract: Liquefied Petroleum Gas (LPG) are commonly used in many practical applications as a storage container for gasses under pressure such as oil refinery, production and fuel stations. Design of LPG vessels must meet strict requirements to insure safety and prevent environmental hazard ASME codes for pressure vessel are a general roles for design and testing for all the available vessels ranging from huge nuclear to small fuel tanks. For specified vessel the designer must has a spatial experience to involve the right criteria. In ASME codes there existed many types of end heads for pressure vessels such as; Torispherical, Elliptical 2:1 and Hemispherical. Selection of head type is left as an option for the designer. In this work an attempt is made to investigate the effect of using three types of end heads on the design of in- service horizontal. Moderate pressure vessel using ASME codes. The studied model represents a practical case in which a horizontal (18 bar) LPG vessel fabricated in Heavy Engineering Equipment State Company (HEESC) - Dura Refinery -Baghdad - Iraq. The design is based on ASME: SEC.VIII div.1 which is suitable for moderate pressure as classified by ASME The results are compared with two commercial design software namely; COMPRESS and PV Elite. It is found that using of hemispherical head can reduce design thickness up to 51.5% as compared with other heads which results economic and light weight vessel, so it is recommended in to be used at HEESC and using the commercial software lead to higher design thickness for all head types.

6. Dynamic behavior of cracked functionally graded (FG) material pipe conveying fluid

Talib EH. Elaikh, Sadiq M. Hmod, Eman R. Bustan

Department of Mechanical Engineer, College of Engineering, Thi-Qar University, Iraq.

Abstract: Dynamic behavior of cracked functionally graded (FG) pipe conveying fluid lying on visco-elastic foundation is investigated in this paper. The crack is demonstrated as a massless torsional spring. The properties of the material are changed constantly across the micro-pipes thickness and depend on power law distribution. Efficient numerical procedure by Galerkin’s method is developed to find the natural frequencies and stability for cracked FG pipe. The effects of cracks location, depth of crack, gradient index, and foundation parameters in FG pipes conveying fluid with certain flow velocity on frequencies are investigated. The present method is carefully checked by comparing their results for cracked pipe conveying fluid with the available results in literature. From the comparison, a reasonable agreement was found (i.e. the maximum discrepancy percentage was 1.5%). The results indicated that the fundamental natural frequency decreased due to the crack presents. Also, the flow velocity for FG pipe increased with gradient index increasing.