Papers by syed shabbar raza
Gasification is a high temperature thermo-chemical pathway that is used to convert a solid fuel/f... more Gasification is a high temperature thermo-chemical pathway that is used to convert a solid fuel/feedstock into combustible syngas (CO and H2) and chemicals. The gasified species derive their formation energy by combusting 20-30% of the feedstock. The combustion resulted in emission of soot, particulate matter, NOx and SOx. Therefore, an attempt is made in this work to offset the energy required for gasification through the use of concentrated solar power, i.e. solar to enthalpy. The system consists of a parabolic and hyperbolic reflector using Cassegrain configuration to concentrate 5 kW of solar flux for the gasifier. Furthermore, a high fidelity computational fluid dynamics (CFD) simulation is established based on the results of thermodynamic and optical models. The CFD simulation couples the effect of heat transfer through solar radiation and reaction kinetics in the participating media. The results demonstrate a cold gasification efficiency of 90% with the product mole fraction ...
SN Applied Sciences
Aluminum production generates enormous spent pot lining (SPL) waste of around one million tons ye... more Aluminum production generates enormous spent pot lining (SPL) waste of around one million tons yearly, and these wastes are usually disposed in landfills. Hence, the technical feasibility of SPL gasification using both equilibrium and reactive high-fidelity modeling was evaluated in this study. Three SPL with different washing treatment, i.e., water (WWSPL), acid treated (ATSPL), and full treated (FTSPL, a combination of both water and acid washing) were used for the modeling. The equilibrium model considered twelve species, while the high-fidelity simulation was modeled with multiple species. Moreover, the high fidelity model is governed by the steady non-isothermal Navier–Stokes equation coupled with the discrete phase in Eulerian–Lagrangian scheme. The process metrics were assessed via the produced syngas fraction (CO/H2) and gasification efficiency (GE). The equilibrium analysis of WWSPL, ATSPL, FTSPL, respectively, resulted in GE of 40, 65, and 75%. The corresponding syngas mol...
International Journal of Thermal and Environmental Engineering
Greenhouse (GH) has been demonstrated as a profitable technology for food production with low dem... more Greenhouse (GH) has been demonstrated as a profitable technology for food production with low demand of irrigation water. In this work, a numerical model is developed to study the micro-climatic environmental conditions inside a greenhouse distillation system for optimize operation. The system performance (temperatures, flow velocities, relative humidity) is presented and improvement factors for the system performance are suggested. The result shows that the inlet velocity and plant transpiration have a more pronounced effect on the relative humidity than the incoming temperature variation. As temperature increases by 8C o the relative humidity decreases with few percentiles (~2%). When velocity varies between 0.2-0.7m/s, and within the diurnal operation of the GH, an increase of up to 5 points in the humidity is observed. Finally, when the transpiration increases from 0.2 to 1.2 g/m 3 the relative humidity observes a drastic jump of over 15 points.
Energy Conversion and Management, Jan 1, 2012
A thermodynamics analysis of gasification process is performed using the Gibbs energy minimizatio... more A thermodynamics analysis of gasification process is performed using the Gibbs energy minimization approach through Lagrange multiplier method. Three different methods of gasification are analyzed to convert bituminous (RTC) coal into syngas (CO and H 2 ). These methods use air, air-steam and solarsteam, respectively, for gasification. Initially the properties of coal are experimentally determined using bomb calorimeter, simultaneous DSC/TGA Q600 thermal analyzer and Flash 2000 (CHNO-S) analyzer to measure higher heating value, proximate and ultimate composition, respectively. Using the experimental data an empirical formula of coal is derived to formulate a gasification model. The model accounts 44 species in the product that also includes for the solid carbon and sulfur. The result of gasification model is presented in terms of equilibrium composition of product gases with the inclusion of minor. In the end, the cold gasification efficiency is calculated that shows the efficiency of 70.94%, 71.64% and 90.67% for air, air-steam and solar-steam gasification, respectively. The cold gasification efficiency clearly shows an added efficiency for solar-steam gasification process.
Fuel, Jan 1, 2011
Thermogravimetric (TG) data of oil shale obtained at MI (Waste to Energy laboratory) were studied... more Thermogravimetric (TG) data of oil shale obtained at MI (Waste to Energy laboratory) were studied to evaluate the kinetic parameters for El-Lujjun oil shale samples. Different heating rates were employed simulating pyrolysis reaction using Nitrogen as purging gas up to $800°C. The extent of char combustion was found out by relating TG data for pyrolysis and combustion with the ultimate analysis. Due to distinct behavior of oil shale during pyrolysis, TG curves were divided into three separate events: moisture release; devolatization; and evolution of fixed carbon/char, where for each event, kinetic parameters, based on Arrhenius theory, were calculated. Three methods were used and compared: integral method; direct Arrhenius plot method; and temperature integral approximation method. Results showed that integral method is closer to the experiment, while no relationship was observed between activation energy and the heating rate.
Energy Conversion and …, Jan 1, 2012
In this study, two methods of gasification are developed for the gasification of various feedstoc... more In this study, two methods of gasification are developed for the gasification of various feedstock, these are plasma gasification and conventional air gasification. The two methods are based on non-stoichiometric Gibbs energy minimization approach. The model takes into account the different type of feedstocks, which are analyzed at waste to energy lab at Masdar Institute, oxidizer used along with the plasma energy input and accurately evaluates the syngas composition. The developed model is applied for several types of feedstock, i.e. waste tire material, coal, plywood, pine needles, oil shale, and municipal solid waste (MSW), algae, treated/untreated wood, instigating air/steam as the plasma gas and only air as oxidizer for conventional gasification. The results of plasma gasification and conventional air gasification are calculated on the bases of product gas composition and the process efficiency. Results of plasma gasification shows that high gasification efficiency is achievable using both tire waste material and coal, also, the second law efficiency is calculated for plasma gasification that shows a relative high efficiency for tire and coal as compare to other feedstock. The average process efficiency for plasma gasification is calculated to be around 42%. On other hand the result of conventional gasification shows an average efficiency of 72%. The low efficiency of plasma gasification suggest that if only the disposal of hazard waste material is considered then plasma gasification can be a viable option to recover energy.
Int. J. of Thermal & Environmental Engineering, Jan 1, 2012
A thermodynamic equilibrium approach is used to calculate the maximum cold gasification efficienc... more A thermodynamic equilibrium approach is used to calculate the maximum cold gasification efficiency (CGE) of different feedstock within the entrained flow gasifier. The high temperature (1000 to 1500 o K), the small feedstock size (10μm to 0.1mm), and the well mixing environment make them most amenable for equilibrium analysis. Four different feedstock, i.e. RTC coal, pine needles, ply-wood and lignite, are used for the gasification purpose. Using air as oxidizer a parametric study is conducted to show the behavior of CGE and product gasification composition by increasing oxidizer input. A gasification model is developed to calculate the seven unknowns in the gasification product. Using four elemental mass balance and three equilibrium constant relations a mathematical code is developed that also incorporate the solid un-burn carbon in product species. Energy equation is used to calculate the temperature of gasification using iterative approach. Result of model shows that the maximum CGE is achieved when all the solid carbon is converted into the carbon monoxide with nearly all hydrogen present in the feedstock converted into the hydrogen gas. Using this result as baseline, a global model to estimate the maximum CGE is developed in reference to Van Krevelen diagram. This model based on minimum requirement of air to convert all the carbon present in feedstock into carbon monoxide. Result shows a growing trend of CGE with the increase O/C and H/C ratio of feedstock.
Int. J. of Thermal & Environmental …, Jan 1, 2010
Hybrid solar thermo-chemical conversion process is a viable route to produce clean fuel using any... more Hybrid solar thermo-chemical conversion process is a viable route to produce clean fuel using any carbonaceous material as feedstock and solar radiation to provide energy for endothermic reactions. The steam gasification of carbonaceous material under high energy solar flux provides a thermo-chemical pathway to produce syngas fuel i.e. hydrogen (H 2 ) and carbon monoxide (CO). Therefore, in this study a steady state model of entrained flow gasifier is simulated utilizing direct solar irradiation as process energy for endothermic reactions inside reactor. Lagrangian approach is used to inject coal particulates in the reactor which immediately undergoes devolatalization and finally steam (H 2 O) gasified. Species transport equations are solved for the concentration of H 2 , CO 2 , CO, H 2 O and nitrogen (N 2 ) as well as the heterogeneous reaction of char (C/fixed carbon) with steam. DO radiation model is applied to simulate 5KW of solar radiation through an optical window inside the reactor. Steady state mass and energy balance are solved to determine the reactor temperature and the composition of product syngas. The resulting problem is then simulated by finite volume method to solve governing mass, momentum, energy and species transport equation. Validation is accomplished by comparing the trends of simulated results with systematic analysis and experiment. The resultant H 2 : CO and CO: CO 2 ratios are computed to be 1.83 and 9.42 respectively. The cold gas efficiency is calculated, which is found to be 105.21% showing the upgraded heating value of product gases by virtue of direct solar radiation.
Gasification is a thermochemical pathway that is use to convert feedstock into combustible syngas... more Gasification is a thermochemical pathway that is use to convert feedstock into combustible syngas (CO and H 2 ). A higher efficiency can be attained by combined cycle when this technology integrated in the power plant (i.e. IGCC) than conventional single cycle coal burning plant. In this work a computational fluid dynamics study is performed to model the gasification of discrete coal particles stream using air as oxidizer. The goal is to understand the effect of the oxidizer's inlet velocity on the conversion of coal particle and syngas composition. To achieve this goal, initially the chemical composition of the feedstock is determined using the proximate, ultimate and calorimetric analysis. The measured results are used to define the coal composition in the numerical simulation. Afterwards, a parametric study for the inlet oxidizer velocity is performed in a tubular downdraft gasifier. The result shows that at lower velocities complete conversion of coal can be attained but at the same time the quality of syngas is not the best by the higher molar fraction of H 2 Compared with CO and lower reduction of the formed CO 2 and H 2 O species. The increase in velocity tends to reduce the conversion of coal particle but also helped the reduction of CO 2 and H 2 O. This is due to the higher attained temperature as the optimal throughput is reached. Further increase in the velocity resulted in significant reduction in residence time and low char conversion and thereby reduction of syngas formation. Furthermore, result of CO and H 2 mole fraction, temperature and velocity contours are presented and discussed.
A first principal modeling of thick wooden slab is performed to investigate the degradation and e... more A first principal modeling of thick wooden slab is performed to investigate the degradation and evolution of tar, char and light hydrocarbon using thermal radiations. Using the governing mass, momentum transport and energy balance equation, a one dimensional model is defined. The governing equations are solved using the finite element method subjected to the initial conditions and boundary conditions. The modeled physical time is 3.5 minutes in which the lumped and discrete quantities are calculated. The wooden slap is exposed to 25 kW/m 2 of thermal radiation that contributes to the temperature gradient across the thick wooden slab. The result shows the exponential decrease in wood mass with respect to time and temperature. The decrease in wood mass directly related to the evolution of char and gas, that are evolving according to Arrhenius based kinetics. Thus the mass of char and gas are also calculated that gives the increasing exponential trend. Finally, the temperature distribution inside the slab is also calculated using the energy equation. Results are compared with the data available in the literature and found in good agreement.
Drafts by syed shabbar raza
The potential energy that algae possess led to re-emergence of a worldwide interest in it as bio ... more The potential energy that algae possess led to re-emergence of a worldwide interest in it as bio fuel 6 feedstock. Algae derived fuel takes many pathways and challenges. Algae enthusiastically embraced in the 7 energy sector as the feedstock which overcomes the current market and technical hurdles. This is because of 8 its diversity in composition, co/production and conversion pathways. The production of algae based bio fuel 9 is however several years away to compete with the Petro fuel. This is mainly due to the additional cost of 10 algae fuel associated with upstream harvesting, dewatering, drying, lipid extraction and trasesterification 11 or/and hydro treating. The quest of finding algae strains that exhibit highest growth, production rate and lipid 12 contents continue. In this work the whole macro algae (enteromorpha) is considered for gasification.
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Papers by syed shabbar raza
Drafts by syed shabbar raza