Driers continuous

Polyethers such as monensin, lasalocid, salinomycin, and narasin are sold in many countries in crystalline or highly purified forms for incorporation into feeds or sustained-release bolus devices (see Controlled-RELEASE technology). There are also mycelial or biomass products, especially in the United States. The mycelial products are generally prepared by separation of the mycelium and then drying by azeotropic evaporation, fluid-bed driers, continuous tray driers, flash driers, and other types of commercial driers (163). In countries allowing biomass products, crystalline polyethers may be added to increase the potency of the product. 

Among other systems of driers, continuous apparatus transporting cellulose on a conveyor belt in a stream of warm air are widely used (Fig. 133). 

ScroU centrifuges discharge soHds continuously and usuaUy drier than disk and imperforate batch types. GeneraUy disk centrifuges have the highest values of Z or for a given size and therefore the best abUity to coUect fine particles at a high rate. 

Zirconium tetrafluoride [7783-64-4] is used in some fluoride-based glasses. These glasses are the first chemically and mechanically stable bulk glasses to have continuous high transparency from the near uv to the mid-k (0.3—6 -lm) (117—118). Zirconium oxide and tetrachloride have use as catalysts (119), and zirconium sulfate is used in preparing a nickel catalyst for the hydrogenation of vegetable oil. Zirconium 2-ethyIhexanoate [22464-99-9] is used with cobalt driers to replace lead compounds as driers in oil-based and alkyd paints (see Driers and metallic soaps). 

Compartment driers are closets or even rooms in which the material is spread on trays or in shallow pans. The operation is often discontinuous in order to make it continuous, the pans may be placed on trucks traveling on rails, and these are pushed through a tunnel in which warm air circulates. Belt driers and chain driers have similar goals. 

The design of driers is dependent on experimental data. Simple tests provide useful information. The normal procedure is to dry a sample (continuously... 

Hanni et al. (1976) described a continuous fluidized bed drier using the centrifugal principle. It consisted of a perforated horizontal cylinder rotating inside a plenum with hot air blown across the outside of the cylinder and perpendicular to the axis of rotation (Figure 1.20). Vanes placed in the air inlet allowed the incident angle of the air flow to be varied from 0° to 45° to the perpendicular. Particles were fluidized inside the Teflon-coated stainless steel cylinder which could be tilted by up to 6° in order to control particle residence time. The cylinder, of... 

Thorpe, G.R., The thermodynamic performance of a continuous-flow fluidized bed grain disinfestor and drier, /. Agric. Eng. Res., 37 (1987) 27-41. 

Borax decahydrate is produced from borate ores, primarily colemanite and also from dry lake brines. When produced from its ore, the ore is crushed and then blended with B2O3. The blend is mixed with hot recycle liquor in a dissolving plant. Rock and clay particles from the liquor are removed over vibrating screens. The hquor is then fed to thickeners for settling of insolubles after which the underflow mud is washed with water. The strong liquor of borax hydrates is then pumped into continuous vacuum crystallizers for the separation of the pentahydrate first and then the decahydrate. The products are dried in rotary or fluid bed driers. 

Liedy W, Hilligardt K. Contribution to the scale-up of fluidized bed driers and conversion from batchwise to continuous operation. Chem Eng Process 1991 30(l) 51-58. 

Solid ammonium nitrate is very deliquescent in moist air, and it is very soluble in water. According to H. Lescceur10 and F. L. Kortright, at 20°, the salt absorbs moisture from the air if the vap. press, of the water is over 9 mm. The vap. press, of a sat. soln. has the same value. It is very difficult to dry the salt it can be obtained with less than 0 1 per cent, of moisture by exposure over phosphorus pentoxide at ordinary temp, in a desiccator. U. Behn observed a slight decomposition of the salt after it had stood a few days in the desiccator. This was evidenced by the smell of nitrogen oxides. If heated, the decomposition is quicker. If one limb of a U-tube containing the salt be heated to 100°, and the other limb be cooled to —79°, water is continuously collected, but the salt becomes no drier. 

---