Mohammad Hamdan

Two-dimensional numerical modeling of combustion of Jordanian oil shale

ABSTRACT A two-dimensional (2-D) modeling of the burning process of Jordanian oil shale in a circulating fluidized bed (CFB) burner was done in this study. The governing equations of continuity, momentum, energy, mass diffusion, and chemical combustion reactions kinetics were solved numerically using the finite volume method. The numerical solution was carried out using a high-resolution 2-D mesh to account for the solid and gaseous phases, k-ε turbulence, non-premixed combustion, and reacting CFD model with the same dimensions and materials of the experimental combustion burner used in this work. The temperature distribution and evolution of species were also computed. Proximate and ultimate analyses were also performed to evaluate the air–fuel ratio and ash content. The required thermophysical properties, such as heating value, density, and porosity were obtained experimentally, while the activation energy was obtained from published literature. It was found that the temperature contours of the combustion process showed that the adiabatic flame temperature was 1080 K in a vertical burner, while the obtained experimental results of maximum temperature at various locations of the burner in actual, non-adiabatic, non-stoichiometric combustion reached 950 K, showing good agreement with the model.

Combustion characteristics of solid waste biomass, oil shale, and coal

ABSTRACT In this study, a developed two-dimensional mathematical model was used to represent the physical model of the combustion process of olive cake and date seed, and solve the governing equations using finite-volume method. The simulation was performed using ANSYS/Fluent software in order to estimate maximum temperature, heating values and pollutants concentrations. The obtained results were compared with experimental results, and corresponding values of oil shale and coal. The experimental work of direct burning of olive cake and date seeds was performed using an existing circulated fluidized bed (CFB) unit. It was found that the adiabatic flame temperatures were 1380 K and 839 K for olive cake and date seed, and 2260 K and 1080 K for coal and oil shale, respectively. The experimental results showed that the maximum temperatures were 1126 K and 723 K for olive cake and date seed, respectively. The lower heating values were 19,500 kJ/kg and 16,400 kJ/kg for olive cake and date seed, and 29,000 kJ/kg and 7000 kJ/kg for coal and oil shale, respectively. Thus, biomass such as date seed and olive cake may be used as an alternative fuel in electrical power plants in olive- or date-producing countries, which may save 40% of fuel cost.

Power quality and stability impacts of Vehicle to grid (V2G) connection

Electric Vehicles (EV) are supplied with storage batteries, which are powered from the grid. So, the EV are considered as a load on the electrical network. But on the other hand, power can be recovered back to the grid in case of out use. This paper study the effect of V2G technology at substation 33kV/11kV located at Amman city, it takes the load profile for each feeder at the substation in to account, the substation and the out feeders build and tested using DIGSILENT software. The harmonic distortion that the charge controller produce it on the grid for eight scenarios at different hours for winter and summer semesters was analyzed, also the effect of V2G technology on the stability was found for fourteen scenarios at different penetration level for electric vehicles, at the end the effect of V2G technology on voltage stability was found for three cases. The results compared with IEEE standard for the allowable harmonic distortion limits where the highest total harmonic distortion occurs at summer peak and high penetration for electric vehicles which equal 0.37%, the frequency stability results compared by the NECA (National Electricity Code Agency).

The performance of hydrogen-powered 4-stroke SI engine using locally designed fuel regulator

In this work, the performance of a spark ignition engine powered with hydrogen fuel was studied and compared with gasoline fuel. Hydrogen fuel was used, using a locally made stainless steel gaseous regulator which was designed and installed in engine. This regulator was located between the engine and the hydrogen fuel cylinder, and it is triggered by the suction pressure and hence it keeps the fuel supply lines open under negative pressure only, which exists under no leak conditions and when the engine is running. It was found that the engine runs smoothly with the regulator in place. Further, it was found that the brake power and the volumetric efficiency of the engine drop down when the engine is powered by hydrogen, while the specific fuel consumption is drastically improved (by almost one-third) when hydrogen is used as a fuel. Finally, the thermal efficiency remains almost the same in both cases of fuels.

Simulation of an Electrical Engine Powered by Fuel Cell–solar Energy Hybrid System

Theoretical simulation has been carried out to find the performance of an electric engine using Advanced Vehicle Simulator (ADVISOR) software. The electric power necessary to operate the engine is supplied either using solar energy that has been converted into electrical energy and then stored in batteries, or using hydrogen fuel cells, which continuously produce electric power that is stored in the batteries. The results obtained under these two conditions were used to compare the performance of the engine. It was found that the engine had better performance when using hydrogen fuel cells than when it is driven by solar energy.