Study of the stability of Ca2AlZrO5,5 ceramics in crude petroleum and production of substrates for temperature sensors for petroleum extraction industry
Rebeka Oliveira Domingues1; Andréa Gonçalves de Sousa2; Mércia Franca de Carvalho1; Renata Oliveira Domingues1; Ricardo Artur Sanguinett Ferreira1; Yogendra Prasad Yadava1
1 Universidade Federal de Pernambuco; 2 Instituto Federal de Pernambuco
doi:10.20906/CPS/COB-2015-1890
Resumo
In petroleum production, various types of sensors are used in order to monitor important parameters such as temperature, pressure and flow. These sensors are subject to hostile operating conditions so they must submit an inert and stable behavior in these working conditions. The temperature sensors, Resistance Temperature Detectors (RTD), are most suitable for the petroleum industry because they have high accuracy and wide temperature range. Generally these devices are built with metal detector elements as resistance temperature encapsulated in inert ceramics and sold at high prices. The goal of this work is to produce new ceramic Ca2AlZrO5,5 with complex cubic perovskite structure for the encapsulation of temperature sensors. Ca2AlZrO5,5 ceramic was produced by thermomechanical processes. Stoichiometric amounts of the chemical constituents (CaO , Al2O3 and ZrO2) were mixed and calcined at a temperature of 1150ºC for 24 hours. The crystal structure of the compound was determined by X-ray diffraction showed that the formation of the complex cubic perovskite ordered structure. The compound was ground and homogenized in ball mill and subjected to particle size analysis. The powder was compacted in the form of circular discs and sintered in the solid state at a temperature of 1300°C for 24 hours. The microstructure and mechanical properties of the sintered discs were studied by OM, SEM, and Vicker's microhardness test, respectively. After these tests the samples were immersed in ground offshore crude petroleum for 60 days and subjected to XRD, OM and Vickers hardness test again to verify the stability of the ceramics in crude petroleum environment. XRD and OM results showed that the structure and microstructure of the ceramics after immersion in crude petroleum remain unchanged. The Vickers hardness test showed a significant increase in average hardness of specimens after the immersion in the crude petroleum. These studies show that the manufactured ceramics are stable in contact with crude petroleum and could be use
Palavras-chave: Ca2AlZrO5,5 ceramics; inert encapsulation; temperature sensors; stability in petroleum