Raw feed

A blending system provides the kiln with a homogeneous raw feed. In the wet process the mill slurry is blended in a series of continuously agitated tanks in which the composition, usually the CaO content, is adjusted as required. These tanks may also serve as kiln feed tanks, or the slurry after agitation is pumped to large kiln feed basins. Dry-process blending is usually accompHshed in a silo with compressed air. 

Parallel feed involves the introduc tion of raw feed and the withdrawal of produc t at each effect of the evaporator. It is used primarily when the feed is substantiallv saturated and the product is a sohd. An example is the evaporation of brine to make common salt. Evaporators of the types shown in Fig. 11-122Z or e are used, and the produc t is withdrawn as a shiny. In this case, parallel feed is desirable because the feed washes impurities from the salt leaving the body. 

The unit consists essentially of tvv o rotating elements, the outer being a solid-shell conical-shaped bowl and the inner comprising a helical-screw conveyor revolving at a speed slightly lovv er than that of the bowl. Raw feed sliiri v is delivered through a stationai"v feed pipe... 

Calculations for all three cases have been performed for the system described in Tables VII and VIII and Figure 6. In this case the raw feed gas was flashed at 66°C and 138 bars with sufficient water to assure that the gas leaving the separator was water saturated. Each of the calculational philosophies described above was used to predict the phase behavior of the systems at each pressure temperature point in the pipeline. The results of these calculations are summarized in Tables IX through XI and Figures 7 through 10. 

The estimated cost for the base case was 148 20% per ton of raw feed, including excavation and pre- and posttreatment costs, bnt exclnding final contaminant destruction costs. Excavation and pre- and posttreatment costs were estimated to be 41% of the total costs. The estimated cost for the hot-spot case was 447, from —30% to 4-50%, per ton of raw feed. Excavation and pre- and posttreatment costs were estimated to be 32% of the total costs (D11243W, pp. 5.3-5.4). 

The vendor estimates that treatment costs nsing a 50- to 60-ton/hr fixed facility operating continuously at full capacity would be about 116 (1993 U.S. dollars) per ton of raw feed, assuming the fines require metals removal and organics reduction (D10059U, p. 3). 

When whole tires are used as supplemental fuel in cement manufacture, they generally enter the process at the upper feed end of the kiln. Depending on the specific process flow at a facility, TDF can be added at the feed end, at the lower (firing) end, or in a raw feed preheater/precalciner that is located before the raw feed entrance. These options are described in more detail in Chapter 4, Tire and TDF Use in Portland Cement Kilns. 

Raw feed material constant diameter limestone (density 2.53 x 103kg/m3 and 2.65 x 103 kg/m3, classified by Tyler standard sieve of 200mm >). Ball mill revolution speed 50, 100, and 150 rpm... 

Parameter Raw Feed Pressurized Feed Interstage Product Reject... 

The ROSA output continues in Figure 10.3. This figure shows the actual and projected water quality throughout the RO system. The "Feed" column represents the raw feed water to the system. "Adjusted Feed" is the projected water quality after pH-adjust or after softening. In this case, "Stage 2 Concentrate" is the project quality of the overall concentrate from the RO. If 3 stages were used, then the "Stage 3 Concentrate" would be the project quality of the overall concentrate from the RO. "Permeate Total" is the projected overall permeate concentration from the system. 

Figure 10.6 shows the projected scaling indices for raw feed, adjusted feed, and concentrate streams. The output includes LSI, alkalinity. 

Consistent effluent quality, regardless of raw feed water quality,... 

Long (LIO) noted that alite size is indirectly affected by both bulk composition and fineness of the raw feed. Increases in LSF, SR or AR all make a clinker harder to burn, which tends to increase the size, though with increased SR or AR, the effect is counteracted by decreases in the quantity and mobility of the liquid, both of which tend to decrease the size. The... 

Effects of bulk composition, raw feed preparation and ash deposition... 

As the thermahy regenerable resin capacity is strongly dependent on solution pH and, thus, on any water, the pH of the raw feed water must be closely controlled at a particular level, near neutrality. This is particularly important when the raw water has a high concentration of carbonate or bicarbonate alkalinity which act as a competing buffer with the dual weak-acid/weak-base resin. It can therefore be advantageous to remove the alkalinity prior to contacting the resin... 

Organisms present in the raw feed sludge might be responsible for the rapid increase in acetate concentration, particularly since their pres-... 

In fact they represent only those data that gave a significant asbestos fiber difference between raw feed water and post-sedimentation water. In some data this difference was not significant. 

DisHlIaHon A wide variety of stills are available to produce purified or distilled water. A typical design consists of an evaporator, vapor separator, and compressor. The distilland (raw feed water) is heated in the evaporator to boiling and the vapor produced is separated from entrained distilland in the separator. The vapor then enters a compressor where the temperature of the vapors is raised to 107°C. Superheated vapors are then condensed on the outer surface of the tubes of the evaporator containing cool distilland circulating within. 

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