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Pyrolysis and combustion behaviors of a single rubber particle in a derivative thermogravimetric (DTG) apparatus were investigated. The influence of temperature (400-8508C) and oxygen content in gas (5-21%) on combustion behavior of rubber samples and solid products of the pyrolysis process (chars) was studied. Development of the porosity and specific surface area of the rubber particle during pyrolysis was investigated.Pyrolysis of scrap rubber samples was carried out under nitrogen atmosphere over a temperature range 20-8508C using a heating rate of 58C/min. The measured DTG curves show two different weight loss regions during the pyrolysis over a temperature range 250-5508C. In all, 52-55% of the samples weight was lost during the pyrolysis process and another 30% during the combustion of char. Ashes create approximately 17% of the samples weight.The ignition temperature of scrap rubber samples in air was around 5128C and increased with decreasing oxygen content. The reaction time of the combustion process decreased about 1.4 times with increasing temperature from 500 to 7508C and 5.5 times with decreasing oxygen content in the inlet gas from 21 to 5 mol%. The total specific surface area of the rubber sample with the degree of pyrolysis increased rapidly to 83 m 2 /g. The values of total porosity increased significantly from 0.3 to 32% at the end of pyrolysis.

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The exchange equilibria of several amino acids, with particular emphasis on those displaying two basic groups, on a strong-acid cation exchange resin (Amberlite IR120) are investigated. The behavior of the experimental data is described through a mathematical model which takes into account the dissociation equilibria of amino acids in aqueous solution, the electroneutrality condition, and an ion-exchange isotherm recently proposed in the literature. In the latter, by assuming ideal behavior for both the solution and the solid phase, the exchange process is treated on the basis of the mass action law, while the existence of a distribution of two types of functional groups with different energies is assumed in order to describe the resin heterogeneity. The developed model is then used in order to satisfactorily correlate binary uptake data and to predict with good accuracy the uptake of amino acids in multicomponent systems.

The simulation of two-phase flow for an experimental airlift reactor (32-litre volume) using commercially available software from Fluent Incorporated is presented here [1]. Data from the simulation is compared with the experimental data obtained by the tracking of a magnetic particle and analysis of the pressure drop to determine the gas holdup. Comparisons between vertical velocity and gas holdup were made for a series of experiments where the superficial gas velocity in the riser was adjusted between 0.01 and 0.075 m s-1 .