Mathematical Modeling of Processes of Zeolite Sorbents Caustic Treatment
Systematic methods and tools for managing the complexity
Process Simulation and Optimization (T4-9P)
Keywords: zeolite sorbents, caustic treatment, process modelling and optimization
Adding caustic treatment stage to the traditional technologies of granulated zeolite sorbents (GZS) production allows to receive sorbents with improved properties: higher mechanical strength, static and dynamic capacity.
The developed model describes the aggregate of the following physical and chemical processes which define changes of the sorbents’ properties: 1) source components of GZS, coupling agents (claying mineral) and adsorbent (synthetic zeolite) in the interaction with caustic solution are partially dissolved with the emergence of the simplest silicate and aluminate ions; 2) as a result of the polycondensation reaction between ions, alumosilicate ions are formed and colloid alumosilicate structures appear; 3) due to the continuous dissolution of the alumosilicate structures the crystallization centers are formed and the zeolite crystals grow in situ.
Using the developed model the problem of caustic treatment of GZS has been solved: for the initial type of GZS (in terms of content percentage and type of claying coupling agent and shape and size of granules) it is required to define such conditions of caustic treatment process realization (concentration and temperature of caustic solution, frequency of mixer rotation, mass composition of liquid and solid phases in the unit), that the optimum of aggregate of adsorption and mechanical properties of GZS is achieved.
Optimization problem has been solved for the industrial prototype of zeolite sorbent 4A, which is broadly used for refinement and drying of cooling agents. Comparison of adsorption and mechanical properties of the prototype zeolite sorbent produced with the traditional technology and zeolite example produced with the suggested optimal conditions of the caustic treatment showed the increase in the following properties: mechanical strength by 36,8 %, adsorption capacity by 14%, and effective diffusion coefficient by 4,3%.
Presented Wednesday 19, 13:30 to 15:00, in session Process Simulation and Optimization (T4-9P).
