Fluidizable zinc titanate materials with high chemical reactivity and attrition resistance
AssigneeResearch Triangle Institute
InventorsRaghubir P. Gupta, Santosh K. Gangwal, Suresh C. Jain
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Abstract
Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 .mu.m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO.sub.3 ; and then indurating it at 800.degree. to 900.degree. C. for a time sufficient to produce attrition-resistant granules.
Claims19
A durable, granulated zinc titanate sorbent material of spherical shape substantially free of sharp edges adapted for fluidized-bed applications, with a surface area of 1-15 m.sup.2 /g and a particle size range of 50-400 .mu.m, prepared from ZnO and TiO.sub.2 in ZnO/TiO.sub.2 molar ratios of 0.5-2.0, an activator/promotor selected from the group consisting of Groups VIB, VIIB and VIII metal compounds, and Groups IA and IIA alkali and alkaline earth metal compounds, in combination in 0-10% by weight, an inorganic binder in an amount of 2.0-15% by weight selected from the group consisting of finely-sized bentonite, kaolinite, forsterite, vermiculite, feldspar, portland cement, oil shale, calcium sulfate and mixtures thereof, and an organic binder in amounts of 0.1 to 5% by weight, selected from the group consisting of Methocel, polyvinyl acetate, cellulose, hydropropyl cellulose, starch, lignin sulfonate and molasses all granulated together, dried, then indurated in an oxidizing environment in a calcination step to form said material.
A process for manufacturing a durable, granulated zinc titanate sorbent material of spherical shape substantially free of sharp edges adapted for fluidized-bed applications, said process comprising the following steps:
- dry mixing finely-sized ZnO and TiO.sub.2 in molar ratios of ZnO/TiO.sub.2 of 0.5-2.0 and an inorganic binder selected from the group consisting of finely-sized bentonite, kaolinite, forsterite, vermiculite, feldspar, portland cement, oil shale, calcium sulfate and mixture thereof in an amount of 2-15% by weight, in a granulator for 1-4 minutes;
- adding an organic binder in amount of 0.1-10% by weight selected from the group consisting of Methocel, polyvinyl acetate, cellulose, hydropropyl cellulose, starch, lignin sulfonate, molasses and mixtures thereof to said dry mixed material;
- granulating the resulting mixture in said granulator at speeds of 2000-8000 rpm for 1-5 minutes to obtain granulates;
- drying the granules at temperatures of 110.degree.-150.degree. C. for 40-80 minutes;
- indurating the granules in a calciner at 750.degree.-950.degree. C. for 1-4 hours in an oxidizing environment;
- screening the material to obtain granulated particles in a particle size range of 50-400 .mu.m.
Dependencies are inferred from the claim text.