A large number of chemical, bio-chemical and pollution-control processes use heterogeneous fixed-bed reactors. The use of finite hollow cylindrical catalyst pellets can enhance conversion levels in such reactors. The absence of the pellet core can significantly lower the diffusional resistance associated with the solid phase. This leads to a better utilization of the catalytic material, which i...

Microkinetics models for the partial oxidations of ethylene and of methanol on silver catalysts are coupled with computational fluid dynamics and implemented in a randomly packed bed of 120 spherical particles. The model includes interactions of the elementary reaction steps and transport inside the particles and the flow field. The effects of using the full implementation of the microkinetics ...

Radial flow reactor was focused for large scale methanol synthesis and in which the heat transfer type was cross-flow. The effects of operating conditions including the reactor inlet air temperature, the heating pipe temperature and the air flow rate on the cross-flow heat transfer was investigated and the results showed that the temperature profile of the area in front of the heating pipe was ...

This paper describes the design and operation of a laboratory plant with a fixed-bed continuous-flow reactor, fully automated and controlled from a personal computer. The automated variables include two gas flows, one liquid flow, six temperatures, two pressures, one circulation of a cooling liquid, and 10 electrovalves. An adaptive-predictive control system was used. The chemical process chose...

Adsorption process is an efficient alternative in metal ions removal. Many materials can be used in this process; among them, we can cite biological materials such as aquatic macrophytes. The macrophytes have shown a high percentage of metal ions removal and they have an advantage of being low cost and have the possibility of growing. In view of this, the aim of this work is evaluate lead remov...

The performance of a fixed-bed and entrained flow reactor for the sorption-enhanced methanol synthesis from CO2 is assessed by modelling. Both reactors achieve good but show possible drawbacks. fixed bed requires several units working in parallel, while needs large volume due to high superficial particle velocity. We propose new type, which combines circulating sorbent with fluidized catalyst b...

Gasification of pyrolysis oil was studied in a fluidized bed over a wide temperature range (523-914 °C) with and without the use of nickel-based catalysts. Noncatalytically, a typical fuel gas was produced. Both a special designed fluid bed catalyst and a crushed commercial fixed bed catalyst showed an initial activity for syngas (H2 and CO) production at T >700 °C. However, these catalysts los...

Superheated steam drying technique has been known for a long time, but its application to food drying has received little attention. In this work, superheated steam was applied to dry fresh parsley (Petroselinum Cripsum). A mathematical model to simulate this drying process was developed by using mass and energy conservation equations for solid and steam phases. The resulting partial differenti...

A mathematical model for the startup period of a fixed-bed reactor with first-order reaction kinetics, axial dispersion and film mass transfer resistance was formulated and solved analytically using Laplace transform. The solution can be used to correlate or predict the reactant concentration profiles in the effluent of the reactor. The effects of both the Peclet number and Biot number on the e...

The adsorption of basic dyes from aqueous solutions onto granular activated carbon and natural zeolite was studied using a fixed bed column. The design procedures for fixed bed adsorption columns were investigated for two basic dyes Maxilon Goldgelb GL EC 400 % (MG-400) and Maxilon Schwarz FBL-01 300 % (MS-300). A computer program based on the solid diffusion control model has been developed. T...