DEVELOPMENT OF PILOT SIZE PROCESS FOR ZEOLITE Y AND ZSM-5 PRODUCTION FROM KANKARA KAOLIN

DEVELOPMENT OF PILOT SIZE PROCESS FOR ZEOLITE Y AND ZSM-5 PRODUCTION FROM KANKARA KAOLIN

Abstract:

The successes recorded at the laboratory for the synthesis of zeolite Y and ZSM-5 using Kankara kaolin sourced from Katsina state, Nigeria as starting material necessitated the need for upscale of the production process. This thesis focused on the development of three pilot size production units and characterizing the products obtained from those units. Pilot size reactors for dealumination and production of zeolite Y and ZSM-5 were developed and test run. Manual means of design was adopted; the materials of construction were carefully selected for the fabrication stage. The process of producing zeolite from kaolin involve, kaolin beneficiation, calcination, dealumination, zeolite recipe preparation and crystallization. The capacity of the pilot size dealuminator, zeolite Y and ZSM-5 reactors were 2.5 kg, 2 kg and 4 kg per run respectively. The reaction temperature and time for the production of zeolite Y were 100°C and 7 hours respectively. Low temperature production of ZSM-5 was achieved at 95°C for a period of 5 days. The physicochemical properties of the raw material, intermediate products (beneficiated kaolin, metakaolin and silica), and final products (zeolite Y and ZSM-5) were characterized using Fourier Transformation Infrared (FTIR), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Thermogravimetry Analysis (TGA), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Selected Area Electron Diffraction (SAED), Energy Dispertive x-ray Spectrometer (EDS), and Brunauer-Emmett-Teller (BET) methods. Dealumination reactor efficiency of 88%, 94%, 97% and 98% in terms of solid product quality was obtained from interior surface without coating, silicone caulk coating, ceramic tiles lining and glass lining respectively. The product obtained from the dealumination reaction was majorly alum and silica. The silica-to-alumina ratio of the zeolite Y produced was 3.08 and the crystals were well formed having a specific surface area, average pore size and pore volume of 321 m2/g, 34 Å and 0.270668 cm3/g respectively. The crystals of ZSM-5 produced were good as revealed by SEM, with high specific surface area of 411 m2/g, average pore size and pore volume of 24 Å and 0.248190 cm3/g respectively. The silica-to-alumina ratio of the produced ZSM-5 zeolite was 77. The quality of zeolite Y and ZSM-5 produced using the developed pilot size reactors were comparable to those synthesized in the laboratory. From the performance test on hydrocracking reaction carried out in a fixed bed reactor, Pt/H-ZSM-5 performed better than Pt/La-zeolite Y. Maximum conversion of n-hexadecane was 98% at reaction temperature of 265 °C for Pt/H-ZSM-5, while 94 % conversion was obtained for Pt/La-zeolite Y at reaction temperature of 315 °C. The prepared catalysts showed high selectivity for gasoline fraction than diesel and lighter fraction products. Cracking was more favored than isomerization during the hydrocracking reaction. The pilot size production units designed had proven to produce good zeolite Y and ZSM-5 from Kankara kaolin which were active in terms of catalytic performance of the zeolite based formulated catalysts.

DEVELOPMENT OF PILOT SIZE PROCESS FOR ZEOLITE Y AND ZSM-5 PRODUCTION FROM KANKARA KAOLIN