Abstract: Due to the environmental and price issues of current
energy crisis, scientists and technologists around the globe are
intensively searching for new environmentally less-impact form of
clean energy that will reduce the high dependency on fossil fuel.
Particularly hydrogen can be produced from biomass via thermochemical
processes including pyrolysis and gasification due to the
economic advantage and can be further enhanced through in-situ
carbon dioxide removal using calcium oxide. This work focuses on
the synthesis and development of the flowsheet for the enhanced
biomass gasification process in PETRONAS-s iCON process
simulation software. This hydrogen prediction model is conducted at
operating temperature between 600 to 1000oC at atmospheric
pressure. Effects of temperature, steam-to-biomass ratio and
adsorbent-to-biomass ratio were studied and 0.85 mol fraction of
hydrogen is predicted in the product gas. Comparisons of the results
are also made with experimental data from literature. The
preliminary economic potential of developed system is RM 12.57 x
106 which equivalent to USD 3.77 x 106 annually shows economic
viability of this process.
Abstract: Tungsten trioxide has been prepared by using P-PTA
as a precursor on alumina substrates by spin coating method.
Palladium introduced on WO3 film via electrolysis deposition by
using palladium chloride as catalytic precursor. The catalytic
precursor was introduced on the series of films with different
morphologies. X-ray diffractometry (XRD), Scanning electron
microscopy (SEM) and XPS were applied to analyze structure and
morphology of the fabricated thin films. Then we measured variation
of samples- electrical conductivity of pure and Pd added films in air
and diluted hydrogen. Addition of Pd resulted in a remarkable
improvement of the hydrogen sensing properties of WO3 by detection
of Hydrogen below 1% at room temperature. Also variation of the
electrical conductivity in the presence of diluted hydrogen revealed
that response of samples depends rather strongly on the palladium
configuration on the surface.
Abstract: Deoxygenation of beef fat for the production of hydrogenated biodiesel is investigated in a high pressure continuous flow fixed bed reactor over palladium-supported mesoporous titania catalyst synthesized via a combined single-step sol-gel process with surfactant-assisted templating method (SATM). The catalyst possessed a mesoporous charactheristic with high surface area and narrow pore size distribution. The main products of all Pd/TiO2 catalysts are n-heptadecane (n-C17) and n-pentadecane (n-C15) resulting from decarbonylation reaction. Pd/TiO2 catalyst synthesized via a combined single-step sol-gel process with SATM (SSSG) gave higher activity and selectivity to the desired products when compared to IWI/SG-TiO2 and IWI/P25-TiO2, respectively. SSSG catalyst gave the average conversion up to 80-90 % and 80 % for the selectivity in diesel range hydrocarbons. This result may cause by the higher surface area and the ability in dispersion of palladium ion in mesoporous of TiO2 during sol-gel process.
Abstract: Performance of a cobalt doped sol-gel derived silica (Co/SiO2) catalyst for Fischer–Tropsch synthesis (FTS) in slurryphase reactor was studied using paraffin wax as initial liquid media. The reactive mixed gas, hydrogen (H2) and carbon monoxide (CO) in a molar ratio of 2:1, was flowed at 50 ml/min. Braunauer-Emmett- Teller (BET) surface area and X-ray diffraction (XRD) techniques were employed to characterize both the specific surface area and crystallinity of the catalyst, respectively. The reduction behavior of Co/SiO2 catalyst was investigated using the Temperature Programmmed Reduction (TPR) method. Operating temperatures were varied from 493 to 533K to find the optimum conditions to maximize liquid fuels production, gasoline and diesel.
Abstract: Supersonic hydrogen-air cylindrical mixing layer is
numerically analyzed to investigate the effect of inlet swirl on
ignition time delay in scramjets. Combustion is treated using detail
chemical kinetics. One-equation turbulence model of Spalart and
Allmaras is chosen to study the problem and advection upstream
splitting method is used as computational scheme. The results show
that swirling both fuel and oxidizer streams may drastically decrease
the ignition distance in supersonic combustion, unlike using the swirl
just in fuel stream which has no helpful effect.
Abstract: Environment-assisted cracking (EAC) is one of the most serious causes of structural failure over a broad range of industrial applications including offshore structures. In EAC condition there is not a definite relation such as Paris equation in Linear Elastic Fracture Mechanics (LEFM). According to studying and searching a lot what the researchers said either a material has contact with hydrogen or any other corrosive environment, phenomenon of electrical and chemical reactions of material with its environment will be happened. In the literature, there are many different works to consider fatigue crack growing and solve it but they are experimental works. Thus, in this paper, authors have an aim to evaluate mathematically the pervious works in LEFM. Obviously, if an environment is more sour and corrosive, the changes of stress intensity factor is more and the calculation of stress intensity factor is difficult. A mathematical relation to deal with the stress intensity factor during the diffusion of sour environment especially hydrogen in a marine pipeline is presented. By using this relation having and some experimental relation an analytical formulation will be presented which enables the fatigue crack growth and critical crack length under cyclic loading to be predicted. In addition, we can calculate KSCC and stress intensity factor in the pipeline caused by EAC.
Abstract: In the first part of the research work, an electrolyzer (10.16 cm dia and 24.13 cm height) to produce hydrogen and oxygen was constructed for single slice O2/H2 fuel cell using cation exchange membrane. The electrolyzer performance was tested with 23% NaOH, 30% NaOH, 30% KOH and 35% KOH electrolyte solution with current input 4 amp and 2.84 V from the rectifier. Rates of volume of hydrogen produced were 0.159 cm3/sec, 0.155 cm3/sec, 0.169 cm3/sec and 0.163 cm3/sec respectively from 23% NaOH, 30% NaOH, 30% KOH and 35% KOH solution. Rates of volume of oxygen produced were 0.212 cm3/sec, 0.201 cm3/sec, 0.227 cm3/sec and 0.219 cm3/sec respectively from 23% NaOH, 30% NaOH, 30% KOH and 35% KOH solution (1.5 L). In spite of being tested the increased concentration of electrolyte solution, the gas rate does not change significantly. Therefore, inexpensive 23% NaOH electrolyte solution was chosen to use as the electrolyte in the electrolyzer. In the second part of the research work, graphite serpentine flow plates, fiberglass end plates, stainless steel screen electrodes, silicone rubbers were made to assemble the single slice O2/H2 polymer electrolyte membrane fuel cell (PEMFC).
Abstract: The position and momentum space information entropies
of hydrogen atom are exactly evaluated. Using isospectral
Hamiltonian approach, a family of isospectral potentials is constructed having same energy eigenvalues as that of the original potential. The information entropy content is obtained in position
space as well as in momentum space. It is shown that the information
entropy content in each level can be re-arranged as a function of deformation parameter.