CARBON ADSORBENT PREPARED FROM WASTE MATERIALS FOR LPG GAS STORAGE MEDIA

Coconut shell and oil palm shell are an agricultural waste material found abundantly in Malaysia. Since the characteristics of coconut shell and oil palm shell were found suitable for preparing activated carbon, these materials also have the potential to be prepared into useful and valuable product. This research, the concern is to make use of coconut shell or oil palm shell which it mixed with plastic bag to prepare the carbon adsorbent, which applied for hydrocarbon gas storage. This sample was prepared at a laboratory scale fixed-bed reactor, which is blanketed by a vertical furnace where pyrolysis took place. Nitrogen gas was used to obtain an inert atmosphere in the reactor. A suction blower was used to remove volatile matter as well as other gases during carbonization process. The samples were prepared in the different peak temperature and amount of the plastic bag which it mixed with them. CO2 activation also was used to investigate the effect of it in the sample. This research work will attempt to find a suitable solution to solve the environmental problems by utilizing the waste materials and to look into the industrial aspect of adsorption process for gas storage

Thermoacoustic cooler with different waveform excitations and the noise control test

Many researchers have been devoted into improving the operation of thermoacoustic cooling system as it offers a promising alternative to traditional cooling methods. This study reported potential system’s improvements that can be obtained when it is operated with different excitation of waveforms and resonator’s material. Resonant test was first carried out to identify the frequency for the operation. Temperature drop that can be obtained by the system was then tested for sine wave, square wave and triangle wave excitations. It was found that a change in resonator material alters the resonance frequency for the operation. Resonance was recorded at 186.6 Hz when acrylic resonator was used while a resonance frequency of 170.5 Hz was found when polyvinyl-chloride’s resonator was used. In term of temperature effects, the square wave excitation resulted to the maximum temperature difference of 45.64˚°C in the acrylic resonator, followed by sine wave at 43.46°C and triangle wave came in last at 40.11°C. Then, as the polyvinyl-chloride’s resonator was used, smaller values of maximum temperature was observed with 38.07°C, 35.94°C and 30.05°C for square wave, sine wave and triangle wave, respectively

Microstructural properties and surface roughness of 3D printed open cell-foam

In this study, the microstructure of open-cell metal foam was generated and reconstructed, to produce a new generation of open-cell foam, which is called 3D printed open-cell foam. At the current stage of research, nylon powder and plastic acid are utilized as the materials for two different 3D printing technologies: Selective Laser Sintering (SLS) and Fused Deposition Modelling (FDM), respectively. The microstructural properties and surface roughness of the 3D printed open-cell foam are investigated using CAD files and microscope images. The surface smoothness and structure strength are found to be dependent on the printing technologies, material employed, and foam size. However, the SLS technology produced smoother ligament surfaces with fewer residues than using the FDM. The ligaments of the small-size 3D printed open-cell foam at the exact size of the metallic foam, on the other hand, are weak and easily shattered. This study also found that the trends of pressure drop from additive manufacturing methods agreed to the original metallic open-cell foam, which are decreasing with the increase of pore sizes

Design optimization of a fixed bed biomass gasifier of a two stage incinerator

Waste wood, a renewable energy source is used as feedstock for Universiti Teknologi Malaysia’s newly-developed two-stage incinerator system. The research goals are to optimize the operation of the thermal system, to improve its combustion efficiency and to minimize its pollutants formation. The work focuses on one of its components, i.e. the primary chamber which comprises of a large updraft fixed-bed chamber, measuring 187.5cm in height and 194.5 cm in diameter respectively. During experimental work, the primary chamber is fed in batches of the processed feedstock while the air for combustion is metered through an eight air nozzle supply system, incorporated at the lower side of the tapered chamber. The feedstock will undergo four different processes; drying, devolatilisation, gasification and combustion. The combustion process is evaluated with the variation of fuel’s moisture content, i.e. set at 17%, 31%, and 40% respectively. The initial experimental work indicates that the temperature and oxide of nitrogen (NO) concentration are decreased with the increase of the moisture in the fuel. Furthermore, the concentration of carbon monoxide (CO) increases with the variation of this operating parameter. However the change for carbon dioxide (CO2) and oxygen (O2) concentrations are only around 1% with the variation of this operating parameter. For optimum operating condition, where the gasification efficiency is 95.53%, the moisture content of the fuel is best set at 17%; giving outlet operating temperature of 550oC and exhaust gas concentrations with 1213 ppm of CO, 6% of CO2, 66 ppm of NO and 14% of O2 respectively. In parallel to the experimental work, a computational fluid dynamics software is used to simulate the performance of the primary chamber at optimum operating condition. This technique provides detail insights on the dynamics of flow and the combustion behavior that occur in the reference chamber. A steady state model is formulated for the updraft fixed bed reactor. Here the predicted optimum gasification efficiency stands at 95.49% with CO, CO2, NO and O2 concentrations as 1301 ppm, 6.5%, 53.7 ppm and 13.5% respectively. The major amendment to the chamber design is proposed on the aspects of air-exit-velocity, i.e. by using smaller diameter of the air nozzles. In doing so, it will create high air-jet penetration in the combustion zone. Higher combustion temperature above 850oC is created for the gasification and combustion zones. This will also reduce NO formation from 54 ppm to 25 ppm at the exit point of the chamber

Thermal performance of optimized interrupted microchannel heat sink (IMCHS) using nanofluids

An interrupted microchannel heat sink (IMCHS) using nanofluids as working fluids is analyzed numerically to increase the heat transfer rate. The rectangular IMCHS is designed with length and width of 10mm and 0.057mm respectively while optimum cut section number, n c=3. The three dimensional governing equations (continuity, momentum and energy) were solved using finite volume method (FVM). Parametric study of thermal performance between pure water-cooled and nanofluid-cooled IMCHS are evaluated for particle diameter in the range of, 30nm to 60nm, volume fraction in the range of, 1% to 4%,nanofluid type of Al 2O 3, CuO, and SiO 2 at Reynolds number range of 140 to 1034 are examined. The effects of the transport properties, nanofluid type, nanoparticle volume fraction and particle diameter are investigated on the IMCHS performance. It is inferred that the Nu number for IMCHS is higher than the conventional MCHS with a slight increase of the pressure drop. It is found that highest thermal augmentation is predicted for Al 2O 3, followed by CuO, and finally for SiO 2 in terms of Nu nf/Nu pw in the IMCHS. The Nu number increased with the increase of nanoparticle volume fraction and with the decrease of nanoparticle diameter

DeltaE modelling and experimental study of a standing wave thermoacoustic test rig

Thermoacoustics is a principle of sciences that could be used to create an alternative green and sustainable technology for a cooler or a generator. Unfortunately, the fluid dynamics of the oscillatory flow within thermoacoustic environment is less understood especially as the flow conditions change to higher values of operating conditions. This leads to difficulties in design practices of the system. In this paper, a test of an experimental rig for the investigation of fluid dynamics of an oscillatory flow inside a standing-wave thermoacoustic rig with two different flow frequencies are reported. An experimental setup was build and numerical modelling is also solved using a thermoacoustic software known as DeltaE. The rig consisted of a quarter wavelength resonator attached to a loudspeaker that acts as an acoustic driver. A structure known as ‘stack’ is located at a location of approximately 0.19 from the pressure antinode. Experimental results showed that the resonance frequency of the two setups are 14.2 Hz and 23.6 Hz, respectively. Measured velocity and pressure at several locations are analysed and the results indicated that the thermoacoustic flow conditions are achieved. The rig could be used for further and deeper investigations of fluid dynamics behaviour for oscillatory flow of thermoacoustic

Study Of Turbulence Characteristics Of An Oscillatory Flow Conditions In Thermoacoustic Using Experimentally Validated Two-Equations Turbulence Model

Oscillatory flow condition is a fluid flow condition that is less understood especially with the presence of structure as found in thermoacoustic environment. Thermoacoustics is a principle of science that involves conversion between thermal and acoustic energy to produce either power or cooling effect. Fundamental studies related to turbulence in oscillatory flow conditions of thermoacoustic environment is needed to help understand potential losses or gain in the system due to the presence of turbulence. This is done through this project where methods such as experiments and computational modellings are used. The test rig was designed using a design software known as DeltaEC. Upon successful design, the rig is fabricated and installed in Turbomachinery Lab, FKM. CFD models of oscillatory flows inside thermoacoustic environment were also solved using ANSYS Fluent and the results are then validated with the experimental works and verified with theoretical equations. Comprehensive analysis leads to the definition of several vortex shedding patterns, boundary layer thickness behavior and relatively new definition of entrance region in oscillatory flow condition was also discovered. The resulting velocity amplitude of flow are then used to calculate the Reynolds number and then the results are mapped into the previously defined turbulence region for oscillatory flow condition in pipe. Results showed that the presence of structure leads to early start of turbulence depending on the length of structure and frequency of the flow. Two graduated MSc students were trained, eight (8) SCOPUS/ISI journal papers were published, 3 articles were submitted into conference proceedings, 1 short publication is also published via participation in MERDs 2017. The research works were presented at three (3) local conferences/symposium and one (1) international conference oversea. One (1) “best paper presentation” award was received at the international conference. Apart from the development of skills and instrumentation for the research group laboratory, the project has contributed towards fundamental understanding of fluid dynamics of the complex oscillatory flow conditions which will help better design for future thermoacoustic energy system as well as other oscillatory flow conditions in another fields such as blood flow and ocean wave