Feed Characteristics

Molten materials can also be cooled to soHd products on endless-belt systems, as shown in Figure 12. Some typical materials treated, product and feed characteristics, and capacities of belt cooling systems are given in Table 5. 

Operation When operated correctly, thickeners require a minimum of attention and, if the feed characteristics do not change radically, can be expected to maintain design performance consistently. In this regard, it is usually desirable to monitor feed and underflow rates and sonds concentrations, flocculant dosage rate, and pulp interface level, preferably with dependable instrumentation systems. Process variations are then easily handled by changing the principal operating controls—underflow rate and floccirlant dose—to maintain stability. 

Automated control schemes employ one or more sets of controls, which will fit into three categories (1) control loops which are used to regulate the addition of tlocciilant, (2) control loops to regulate the withdrawal of Iindertlow, and (3) rake dri e controls. Usually, the feed to a thickener is not controlled and most control systems ha e been designed with some tlexibility to deal with changes in feed characteristics, such as an increase in oliirne or alteration in the nature of the solids thernseh es. In se ere cases, some equalization of the feed is required in order to allow the control system to perform effecth ely. 

Running different products through mill, or change in upstream process, resulting in different feed characteristics and unsuitable milling conditions, e.g. overheating due to blocked outlet... 

What is the effect of moisture on the flowability and feeding characteristics of dry bulk filter aids ... 

The important process variables are reactor temperature, residence time, and steam/hydrocarhon ratio. Feed characteristics are also considered, since they influence the process severity. 

Several preparation steps after soil excavation are required to achieve the optimum inlet feed characteristics for maximum contaminant removal ... 

Table 9.11 Feed characteristics of a four-component mixture. 

Barret M, Cea-Barcia C, Guillon A, Cerrere H, Patureau D (2010) Influence of feed characteristics on the removal of micropollutants during the anaerobic digestion of contaminated sludge. J Hazard Mater 181 241-247... 

The feed characteristics of cold rubber compounds differ considerably from those of hot compound to the extruder and a number of devices were developed to overcome this problem. However, the productivity of the early machines was not as high as for the hot-feed machines. 

Smith, W.S., Sickles, R.A., Miller, LA., and Womer, T.W., An Experimental Investigation into Solids Feeding Characteristics of a Single Piece Barrel with Integral Feed-port Design vs a Standard Two Piece Water Cooled Feedblock and Barrel Configuration, SPE ANTEC Tech. Papers, 53, 390 (2007)... 

Over 30 man-years of effort were involved in developing the model, which is named KINPTR, an acronym for kinetic platinum reforming model. Since its development, KINPTR has had a major impact in Mobil s worldwide operations. It can be accessed by personnel at each of Mobil s locations throughout the world. Input requirements are simple and convenient making it very user friendly. Only feed characteristics, product quality targets, process configuration information, and process conditions are required for input. Output is informative and detailed. Overall and detailed yields, feed and product properties, and reactor performance data are given in the output. 

One of the primary problems to be encountered in energy conversion facilities will be the variability of the feedstock. A coal or oil shale facility will probably see greater variability, day-by-day, than experienced in planned changes in oil refinery crude runs. Even with extensive blending in the feed stockpile, the variation in feed characteristics will be significant. 

Application Filter area, m2 Slurry feed characteristics % solids pH t/hr Wash ratio (wt/wt based on dry solids) Solubles recovery % Final cake moisture %... 

The manner in which Ni and V sulfide deposits accumulate on individual catalyst pellets depends on the kinetics of the HDM reactions as influenced by catalyst properties, feed characteristics, and operating conditions. The dynamic course of deactivation of catalytic reactor beds is also determined by the kinetics of the HDM reaction. The lifetime and activity of a reactor bed are directly related to the details of the metal deposit distribution within individual pellets. This section will review deactivation behavior of reactor beds in light of our understanding of the reaction and diffusion phenomena occurring in independent catalyst pellets. Unfortunately, this is an area of research which remains mostly proprietary with too little information published. What has been published is generally lacking in detail for the same reason. 

Figure 9.8 Cross mixing and axial mixing as a function of the material feed characteristic and the residence time distribution...

Tedder and Rudd (1978) present the results of a study of the economics of separating a variety of three component mixtures using a variety of thermally coupled and ordinary columns. Their goal was to expose trends. They show which feed characteristics favor which column structure. 

Feed characteristics. Is the material sufficiently fine to ball it by tumbling agglomeration Is it sufficiently plastic to allow extrusion If a slurry... 

The catalytic isomerization of -pentane was carried out in a once-through fixed bed flow reactor using helium as a carrier gas, at a standard temperature of 523 K in the absence and presence of dihydrogen in the feed. Characteristic rate and selectivity data are compared in Table 2 for WZ and PtWZ.21,35... 

Steam cracker tar (SCT) is a by-product from the steam cracking of naphtha or gas oils to produce ethylene. The characteristics and yield of SCT is dependent on the feed characteristics, the plant design and severity of cracking,... 

Figure 23.7 presents a simplified mid-1980s flow diagram for the Siilinjarvi phosphate beneficiation plant in Finland. The low-grade igneous ore to this plant is carefully blended to avoid changes in plant feed characteristics. Liberation of phosphate is achieved by rod milling followed by closed... 

Once-through ethylene yields depend on feed characteristics and severity, and range from 58% for ethane to 36% for liquid feeds. 

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