Incoming solids

Separation Efficiency. Similarly to other unit operations in chemical engineering, filtration is never complete. Some soflds may leave in the hquid stream, and some Hquid will be entrained with the separated soHds. As emphasis on the separation efficiency of soHds or Hquid varies with application, the two are usually measured separately. Separation of solids is measured by total or fractional recovery, ie, how much of the incoming solids is coUected by the filter. Separation of Hquid usually is measured in how much of it has been left in the filtration cake for a surface filter, ie, moisture content, or in the concentrated slurry for a filter-thickener, ie, solids concentration. 

In counterflow movement, heat from the outgoing sohds is transferred directly to cold incoming solids, reducing heat losses and fuel requirements. Continuous conveyor ovens are employed also for diy-ing refractoiy shapes and for drying and baking enameled pieces. In many of these latter, the parts are suspended from overhead chain conveyors. 

Flotation Air flotation has proved to be successful in concentrating secondaiy sludges to about 4 percent solids. The incoming solids are normally saturated with air at 275 to 350 kPa (40 to 50 psig) prior to being released in the flotation tank. As the air comes out of solution, the fine bubbles are trapped under the suspended solids and cany... 

As discussed in Section 15.5.2, the separation of two or more sublimable substances by fractional sublimation is theoretically possible if the substances form true solid solutions. Gillot and Goldberger(10°) have reported the development of a laboratory-scale process known as thin-hlm fractional sublimation which has been applied successfully to the separation of volatile solid mixtures such as hafnium and zirconium tetrachlorides, 1,4-dibromobenzene and l-bromo-4-chlorobenzene, and anthracene and carbazole. A stream of inert, non-volatile solids fed to the top of a vertical fractionation column falls counter-currently to the rising supersaturated vapour which is mixed with an entrainer gas. The temperature of the incoming solids is maintained well below the snow-point temperature of the vapour, and thus the solids become coated with a thin film (10. im) of sublimate which acts as a reflux for the enriching section of the column above the feed entry point. 

Automatic Control. In some industries, the waste streams can vary in composition over a relatively short lime period When the solids level of a slurry changes, the entire dosage response may change. Automatic systems are available for thickeners that adjust the dosage according to the incoming solids level, overflow turbidity, and streaming current potential. 

For maximum heat economy, recovered exhaust heat is employed for preheating of the incoming solids and combustion air. The fuels used may be gas, oil, or pulverized coal. 

City Finds Disposal Solution, N, Little Rock Picks Modular Incinerator for Steam and Income, Solid Wastes Management (March 1978). 

The fluidized bed reactor is a relatively new approach to the design of high heat release combustors. The primary functions of the air-fluidized inert bed material are to promote dispersion of incoming solid fuel particles, heat them rapidly to ignition temperature, and to promote sufficient residence time for their complete combustion within the reactor. Secondary functions include the uniform heating of excess air, the generation of favorable conditions for residue removal, and the ability to reduce gaseous emissions by control of temperature or by use as a gas-solids reactor simultaneously with thermal conversion. 

The labels on the right of the double bar represent incoming or precollision electrons, and we draw incoming solid lines. If the orbital is occupied, the lines comes down and in if it is unoccupied, the line comes up and in and if the orbital is a general one, the line comes in horizontally. 

For such flocculator-clarifiers the hydraulic flow must be steady and maintain a steady fluidization of the existing floe particles the incoming flocculating particles must aggregate to a size equal to the existing floes or, more likely, be collected on them and there must be a balance between the incoming solids and the withdrawal of excess floe to maintain a steady state. 

The third stage consists of a vapor recovery reactor (VRR), where Al and AI2O vapors react with C to form AI4C3 (unless gas Al species are recovered countercurrent to the incoming solid feed, metal loss has a catastrophic impact on the process economics). 

Assuming that solid flow fluctuations can be damped in an expansion section in the same manner as gas pulsation in compressor systems, determine the length of 0.0508-m-ID pipe needed to damp 25% of the incoming solid flow fluctuations. The solids are coal particles with a density of 1280 kg/m and an average diameter of 150 jum, and they are flowing in a 0.0254-m-ID pipe in a gas stream with a density 1.2 kg/m and velocity of 15.25 m/sec. The solid flow fluctuation is 10 cps and the particle velocity can be found by use of Hinkle s correlation. 

Here, we will determine the overall separation efficiency for saltation conditions, i.e. when Cg > Col- This efficiency includes the efficiency due to saltation in the inlet and the efficiency due to classification in the inner vortex. A portion of the incoming solids that is not collected by the former is collected by the latter, so that the total efficiency becomes (see also Chap. 9) ... 

Independently of the equation selected to describe the inner-feed particle size distribution, all such equations can only be regarded as rough approximations to the true size distributions. Fortuitously, perhaps, in most practical situations wherein saltation or mass loading effects occur, the effect tends to dominate the overall collection process and so only a small portion of incoming solids ever report to the inner vortex. As a consequence, the overall collection efficiency is not highly sensitive to the choice of distribution function for the inner feed. If, however, one is only interested in the loss fraction, a difference in the total overall efficiency of 0.9992 and 0.9998, for example, can be significant since, in this case, the amount lost differs by a factor of 4. 

As suggested by Heumann, and on basis the writers own observations, any void or attic space above the inlet plane tends to cause incoming solids to... 

Cyclones are quite forgiving for changes in the inlet velocity. Depending on the particular application, they will often operate reasonably well even if the inlet velocity drops to 5 m/s. If the incoming solids are being pneumatically conveyed into the cyclone, one has to be watchful that they do not salt out in the ducting upstream of the cyclone. This can lead to unstable flow and poor overall collection performance. Also, some products deteriorate if allowed to sit around in the inlet ducting. 

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