Papers by Keyword: Fuels

Abstract: Catalytic hydrogenation of CO₂ into fuels and chemicals is regarded as one of the most promising alternatives to reduce the concentration of CO₂ in the atmosphere. In this study, double-promoted Cu/ZnO catalysts were prepared on Al₂O₃ and CNTs supports via impregnation method. The physicochemical properties of the catalysts were characterized by XPS, TEM, N₂ adsorption, H₂-TPR and CO₂-TPD analyses. Introduction of Nb and Zr promoters into the Cu-based catalysts on CNTs support resulted in smaller Cu nanoparticles and improved reducibility compared to those of the Al₂O₃-supported catalyst. The catalyst activity was evaluated in a fixed-bed stainless steel reactor operated at 22.5 bar and 523K. Conversion of CO₂ higher than 20% was achieved and product distribution was influenced by the type of catalyst supports.

Abstract: Thermogravimetric analysis is also used for the determination of mass composition changes of solid fuels caused by heating processes, coal, and wood or plant debris. Energy characteristics of coal depends on the age of their formation (geological age) and the transformations undergone by organic matter under the influence of geological chemistry (chemical age). Several classification criteria, excluding other problems that may arise in connection with the extraction, preparation and other use than combustion, several classifications have been proposed enabling the sharing of the multitude of solid fuels in groups so that each group members behave similarly during the combustion procedure. Wood and plant debris, combustible wastes, coal, have a heating value depending on their mass composition.

Abstract: The mixtures formation process based only on molecular diffusion proved to be the slowest. The mixing speed is reduced due to the collision of molecules of two or more gases which are subjected to the mixing process. The gases concentrations have an important role in mixture formation. Air is one of the combustion gases in the case of mixing in order to achieve the burning process.

Abstract: This paper is focused on the numerical simulation of a new technology of small size iron ore sintering machine using gaseous fuel and oxygen injections to produce high quality of sinter product for the blast furnace operation. The proposed methodology is to partially replace the solid fuel (coke breeze) by steelworks gases in a compact machine to enhance heat and mass transfer. A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction rates and phase transformations is proposed to analyze the inner process parameters. A base case representing a possible actual industrial operation of the sintering machine is used in order to compare different scenarios of possible operations which represents advanced operations techniques. The model was used to predict four cases of fuel gas utilization: a) 3% of the wind boxes inflow from N01-N10 wind boxes of natural gas (NG) and oxygen, b) same condition with coke oven gas (COG) and c) mixture of 80% COG and 20% blast furnace gas (BFG). The model predictions indicated that for all cases, the sintering zone is enlarged and the solid fuel consumption is decreased about 12kg/t of sinter product for the best combination. In order to maximize the steelworks gas utilization it is recommended the use of mixture of COG and BFG with optimum inner temperature distribution within a compact sintering machine, which enhance the productivity and obviously, decrease the investment cost of the sintering facilities.

Abstract: A computational study to assess the effect of gas turbine (GT) frame size on efficiency of gas turbine power plant configurations is presented in this paper. The work includes the effect of relative humidity (RH), ambient inlet air temperature and frame size on gas turbine plant configurations with and without fogger unit. Investigation also covers economic analysis. 20 MW_e GE 5271RA, 40 MW_e GE-6561B and 70 MW_e GE-6101FA frames are selected for the present study. GT PRO software has been used for carrying out the analysis including; net plant output and net efficiency, break even electricity price (BEEP) and break even fuel LHV price (BEFP), etc. The relative humidity and temperature have been varied from 30 to 45 % and from 80 to 100° F, respectively. Fuels considered in the study are natural gas, diesel and crude oil. Results show that variation of humidity does not affect the gas turbine performance appreciably for all GT frame size regardless of type of fuel. For a decrease of inlet air temperature by 10 °F, net plant output and efficiency have been found to increase by 4 and 1.7 %, 4.2 and 1.3 %, 4.7 and 1.8 %, respectively for 20 MW,40MW and 70MW for crude oil and for GT only situation. However, for GT with Fogger scenario, for a decrease of inlet air temperature by 10 °F, net plant output and efficiency have been found to further increase by 3.1 and 1.3 %, 3 and 0.9 %, 3.2 and 1.1 %, respectively for 20 MW,40MW and 70MW. For situations with and without fogger for crude oil, BEFP have been found to vary from 1.3968 to 1.3916, 2.13 to 2.0948, 2.387 to 2.4642 USD/MMBTU respectively for 20 MW, 40MW and 70MW and BEEP have been found to vary from 0.03142 to 0.0313, 0.02488 to 0.02504, 0.0229 to 0.0233 USD/kWh respectively for 20 MW, 40MW and 70MW.

Abstract: This paper deals with the numerical simulation of the new technology of gaseous fuel utilization on the sintering process of iron ore. The proposed methodology is to partially replace the solid fuel(coke breeze) by steelworks gases. A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction rates and phase transformations is proposed to analyze the inner process parameters. A base case representing the actual industrial operation of a large sintering machine is used with thermocouples inserted into the sintering bed to record the inner bed temperatures and compare with model predictions in order to obtain model validation and parameters adjustment. Good agreement of the temperature pattern was obtained for the base case and thus, the model was used to predict four cases of fuel gas utilization: a) 2% of the wind boxes inflow from N01-N15 wind boxes of natural gas(NG), b) same condition with coke oven gas(COG), c) same condition with blast furnace gas(BFG) and d) mixture of 50% COG and 50% BFG. The model predictions indicated that for all cases, except only BFG, the sintering zone is enlarged and the solid fuel consumption is decreased about 8kg/t of sinter product. In order to maximize the steelworks gas utilization it is recommended the use of mixture of COG and BFG with optimum inner temperature distribution

Abstract: Production and characterization of fatty acids methyl esters (FAME) from palm oil (PO), palm kernel oil (PKO) and groundnut oil (GNO) were carried out in this study. Optimal amount of NaOH catalyst required for the transesterification of the degummed and refined oils were determined. Some rheological and fuel quality parameters of the FAME obtained from batch transesterification of each oil, petrodiesel and their blends, were determined. The optimal catalyst weights obtained, based on oil, were 0.40, 0.48 and 0.56 (%wt/v) for GNO, PKO and PO, respectively. The FAME produced had viscosities of 4.45, 3.44, and 4.11mm²/s as compared to the 38.84, 37.51 and 36.92mm²/s obtained for the parent oils PO, PKO, and GNO, respectively. The measured viscosity of petrodiesel was 2.85mm²/s. Thermodynamic free energies of activation for flow (∆G_vis) for the FAME samples were 18.1, 13.4 and 14.7KJ/mol for PO, PKO, GNO, respectively, and 10.1KJ/mol for petrodiesel.

Abstract: The aim of this work is to evaluate the influence of fuel in the synthesis of ZnAl2O4 catalytic supports by combustion reaction. For this, it was used the fuels: urea, carbohidrazide, glycine and aniline. The total amount of reagents was calculated according to the theory of propellants and explosive using urea in the stoichiometric proportion (Φe = 1). The structural and morphological characteristics of the powders were evaluated by XRD, FTIR, TEM, SEM and particle size distribution. The results from XRD showed the formation of the normal cubic spinel structure. The powders presented nanosized particles with narrow agglomerates size distribution. The powders prepared with urea showed better value of surface area and smaller crystallite size.

Abstract: This study presents the experimental results of using admixture of used engine oil and kerosene as an alternative fuel in foundry shops. In this experiment, several proportions of used engine oil (well filtered) and kerosene were measured to make 1000ml per mixture using a calibrated beaker. Each mixture was fired in a furnacensuring atomization, ignition and combustion in a timed set up. Results of the experiment showed that admixtures of 100%, 95% and 90% volume of used engine oil gave low pour point hence were incombustible. 85%, 80% and 75% volume of used engine oil admixtures gave carburized flame. While 55% and below of used engine oil volume of admixtures gave oxygenated flame. 57% - 70% volume of used engine oil admixtures produced neutral flame which is ideal for melting. Of the latter proportions, 70% of used engine oil admixture had the highest heat content 70,780 kj/kg and the lowest cost. Hence this admixture is recommended as an effective admixture for fuel substitution in the foundry shop.

Abstract: Significant technical challenges still remain today for the fuel cell in a number of areas including reliability, durability, cost, operational flexibility, technology simplification and integration, fundamental understanding and life cycle impact. New advanced materials and associated innovative engineering design will be required to close these technical gaps. This paper provides a perspective on fuel cell technology today, research and development directions, challenges going forward, and a future view of the fuel cell.