Effect of nepheline syenite particle size on diametrical compression strength and reliability of extruded ceramic Raschig rings used in packed towers

Abstract

In order to understand the effect of nepheline syenite particle size on physico-chemical properties of ceramic Raschig rings, the fluxing agent was grinded at different milling times. The compositions were prepared by blending the illitic-kaolinitic clay and pre-grinded particles. The rings were shaped by a laboratory extruder and then were sintered at 1200 ºC. The mechanical reliability of sintered specimens was mathematically described by Weibull theory and the effect of pre-grinding of fluxing agent on Weibull modulus was evaluated by measuring the diametrical compression strength. Weibull modulus and strength were the criteria for selecting the suitable particle size range of nepheline syenite. It was found that the pre-grinding of nepheline syenite acts as fairly strong parameter on microstructure of rings. The investigation concludes that reliable rings can be fabricated if the particle size of nepheline syenite is arranged between 53 and 75 μm. This enhancement in reliability is valuable in packed towers.<br><br>Para conocer el efecto del tamaño de partícula de nefelina sienita sobre las propiedades fisicoquímicas de los anillos Raschig cerámicos, este fundente fue molido a diferentes tiempos. Las composiciones se prepararon mediante la mezcla de la arcilla caolinítica illitica y las partículas pre-molidas. Los anillos se obtuvieron en una extrusora de laboratorio y luego fueron sinterizados a 1200 ºC. La fiabilidad mecánica de las muestras sinterizadas se describe matemáticamente por la teoría de Weibull y el efecto de pre-molienda del fundente en el módulo de Weibull se evaluó midiendo la resistencia a la compresión diametral. El módulo de Weibull y la resistencia fueron los criterios para seleccionar el rango de tamaño de partícula adecuado de nefelina sienita para la fabricación de los anillos que se determinó estaba entre 53 y 75 μm comprobándose que influye considerablemente en la microestructura de los mismos. La fiabilidad alcanzada fue muy valiosa para la utilización de estos anillos como relleno en ldistintos tipos de torres

Relationship Between Powder Composition and Single Screw Extrusion for Manufacturing Reliable Random Ceramic Packed Bed According Statistical Approach

“…The ceramic bed compositions at least consist of three components that play the fundamental roles in processing and performance of chemical units. Kaolin, for plasticity [9,12], nepheline syenite [13,14] or talc [15] with limited content as fluxing agents and alumina and zirconium silicate [16] as fillers were applied. After suitable processing, these formulations should lead to a matrix with high strength and appropriate chemical resistance [7,16].…”

“…Consequently, the crack grows slowly until reaching the critical size for fracture. Literatures report the Weibull modulus values for ceramic Raschig rings between 3 and 15, [13][14][15][16]. This introduces the necessity to investigate the reliability of ceramic beds, which are normally polycrystalline solids, existing in abundant glassy phase.…”