Mehdi Rezaei

Mathematical modeling of unsteady-state gasification of petroleum residue

ABSTRACT Gasification is a thermochemical process which converts organic fuels into a high caloric value syngas and other chemicals in the presence of a gasification agent. Tar generation represents the strongest barrier for the use of fixed-bed reactors for liquid fuel gasification, whereas sufficing is only possible with catalytic activities and expensive physical processing. In this work, a kinetic model of waste oil gasification was proposed which can be used a flexible model to provide a quantitative prediction of product yield of other fuels. Results were validated against the experimental measurements and showed a good agreement. In accordance with the modeling results, it was found that the greenhouse gas emission (GGE) of waste oil is higher than that of biomass materials, but the caloric value of the syngas generated is higher. The residence time was also recognized as an important design parameter to improve the syngas volume fraction.

Kinetic modeling of biomass gasification in a micro fluidized bed

ABSTRACT This paper presents a goal programming model to predict the kinetic parameters of micro fluidized bed (Micro-FB) gasification of woody biomass in Qom, Iran. Qom has an abundance of waste woody biomass, and gasification can convert this residue into clean syngas. To do this, a kinetic model of biomass gasification was developed and validated against the experimental data available in the literature. The experiments were carried out in a Micro-FB in the presence of silica sand as the fluidization medium. To fully decompose the aromatic tars, the reaction temperatures were considered between 700°C and 1000°C with 100°C intervals. Results showed that the obtained activation energies strongly depend on the particle size for all the tested conditions.

Experimental study of steam-gasification of municipal solid wastes (MSW) using Ni-Cu/γ-Al 2O3 nano catalysts

ABSTRACT There is an increasing interest in the conversion of municipal solid waste (MSW) due to its low cost and high potential for production of syngas and chemicals. Gasification is a promising thermochemical process to transform carbon-based fuels into a valuable fuel/syngas. In this article, an experimental study of air-gasification of municipal solid waste (MSW) using Ni-Cu/γ-Al2O3 nano catalysts was developed. The particle sizes were ranged from 0.3 mm to 0.35 mm and loaded into the Micro-FB system at the beginning of each experiment. The influence of type of catalysts, gasification temperature and catalyst loading on tar concentration, hydrogen yield, and char conversion was evaluated. Results showed that with increasing the gasification temperature, the hydrogen yield gradually increases from 25 to 34 g/kg fuel at 600°C and 24 to 32 g/kg fuel at 800°C when using Ni/γ-Al2O3 and Cu/γ-Al2O3 catalysts, respectively. It also found that the use of metal catalyst during the gasification process is an influential parameter affecting the evolution profiles of gasification products, especially for hydrogen.

Classification of finite groups according to their conjugacy class lengths

Abstract In this paper, we classify all finite groups satisfying the following property: their conjugacy class lengths are set-wise relatively prime for any six distinct classes.

A time-independent kinetic model for syngas production from oxy-fuel gasification of waste oil

ABSTRACT Clean heat and power generation for industrial applications is a major challenge in the recent decade. Gasification is a clean thermochemical process to produce syngas through partial oxidation. In this paper, we develop an unsteady state kinetic model of gasification to produce syngas from petroleum residue and also evaluate the tar and char yield in the oxy-fuel conditions. Results showed that the oxy-fuel gasification can be used to produce high caloric value syngas with low emissions and costs. It is also found that the system pressure reduces the hydrogen yield, although it is not considerable. Modeling results validated against the experimental data and found to be in a good agreement.