(585au) Evaluation of Forming and Mechanical Properties of Catalysts Base Zeolite

Karla D. Guerrero G.; Julio C. Vargas

The formulation of catalysts and the techniques to obtain them are subjects of great interest for their application in processes of obtaining and / or transformation of raw materials. Several researches have been developed to establish scientific and technical bases for the formulation of ceramic catalysts, such as zeolite base catalysts, by studying the influence of the components of the formulation on the mechanical properties And also correlating the rheological (ie fluidity) characteristics of the formulated mixtures with the final mechanical properties of the extrudate.

The catalysts developed for hydropupture processes consist of an active phase (zeolite and metal), a support or binder (alumina, silica, silica-alumina, among others) and sometimes acidity promoters (chloride or fluoride groups). During the formation of the catalyst, the addition of water and extruding agents is necessary to obtain the geometry desired for use in the reactor, with low pressure drops and suitable hydrodynamic regimes. The proportion at which the catalyst components are mixed during the forming, directly affect the final mechanical properties.

The general objective of this work was to evaluate the influence of the formulation and the forming conditions on the mechanical properties of a zeolite base catalyst. To achieve this objective the effect of zeolite concentration, water content and extrusion agent on the physical-mechanical properties of the extrusion mixture was studied. The influence of the extrusion and preparation conditions on the physical properties of the catalyst pellets was analyzed. And the influence of the process conditions (drying and calcination) was evaluated with the mechanical properties of the catalysts obtained.

It was taken as a reference that generally the ratio between the zeolite and the support can be set at 65/35, with variations in the percentage of zeolite between 60 and 70% and between 30 and 40% for silica-alumina, the water content of blend varies between 40-50% of the total weight of the solids in the blend and extrusion assisting agents are used in percentages less than 10% relative to the total mass of solids involved.

In order to evaluate the manufacturing conditions of the catalyst extrudates, the drying rate and the calcination rate were manipulated. During the drying process, each piece was subjected to heating gradients as a function of relative humidity. Initially, the lower speeds provide adequate conditions for the diffusion of the water molecules from the interior of the piece to its surface avoiding the formation of cracks and damage to the structure of the extrudate. Drying was performed between ambient temperature and 120 ° C and the drying rate range was varied between [0.1-2] ° C / min. For this experiment, two drying temperatures of 90 ° C and 120 ° C were evaluated with drying rates of 1.0 ° C / min and 2 ° C / min. In the calcination process, the heating rates were higher than the drying rates, however, they had to ensure that the re-accommodation of the molecules in the structure and calcination of the organic components did not generate the destruction of the pellet for this process. Used a range of speeds between [1-10] ° C / min. For this step a calcination temperature of 450 ° C was set and two calcination rates were evaluated 6 ° C / min and 10 ° C / min.