Feeding types

The second type of hoUow-fiber module is the bore-side feed type illustrated in Figure 23b. The fibers in this type of unit are open at both ends, and the feed fluid is usually circulated through the bore of the fibers. To minimize pressure drops inside the fibers, the fibers often have larger diameters than the very fine fibers used in the shell-side feed system and are generally made by solution spinning. These so-called capillary fibers are used in ultrafiltration, pervaporation, and in some low to medium pressure gas appHcations. Feed pressures are usually limited to less than 1 MPa (150 psig) in this type of module. 

The q line, therefore, depends on the enthalpy condition of the feed. Types of q lines are shown in Figure 9 and are hsted below. 

FIG. 12-98 Feed-type ring dryer. (Batr—Rosin)... 

Cake Thickness Control Sometimes the rate of cake formation with bottom feed-type filters is rapid enough to create a cake too thick for subsequent operations. Cake thickness may be controlled by adjusting the bridge-blocks in the filter valve to decrease the effective submergence, by reducing the slurry level in the vat, and by reducing the vacuum level in the cake formation portion of the filter valve. If these measures are inadequate, it may be necessaiy to use a toploading filter. 

Capacity can vary depending on breaking characteristics and compression strength of each installed horsepower, size of feed, rate of feed, type of fall, and proper operating conditions. 

Products from coking processes vary considerably with feed type and process conditions. These products are hydrocarbon gases, cracked naphtha, middle distillates, and coke. The gas and liquid products are characterized by a high percentage of unsaturation. Hydrotreatment is usually required to saturate olefinic compounds and to desulfurize products from coking units. 

Feeds to hydrotreatment units vary widely they could he any petroleum fraction, from naphtha to crude residues. The process is relatively simple choosing the desulfurization process depends largely on the feed type, the level of impurities present, and the extent of treatment needed to suit the market requirement. Table 3-12 shows the feed and product properties from a hydro treatment unit. ... 

Liquid feedstocks for olefin production are light naphtha, full range naphtha, reformer raffinate, atmospheric gas oil, vacuum gas oil, residues, and crude oils. The ratio of olefins produced from steam cracking of these feeds depends mainly on the feed type and, to a lesser extent, on the operation variables. For example, steam cracking light naphtha produces about twice the amount of ethylene obtained from steam cracking vacuum gas oil under nearly similar conditions. Liquid feeds are usually... 

This is a more advanced partial combustion process. The feed is first preheated and then combusted in the reactor with a limited amount of air. The hot gases containing carbon particles from the reactor are quenched with a water spray and then further cooled by heat exchange with the air used for the partial combustion. The type of black produced depends on the feed type and the furnace temperature. The average particle diameter of the blacks from the oil furnace process ranges between 200-500 A, while it ranges between 400-700 A from the gas furnace process. Figure 4-4 shows the oil furnace black process. 

As with HjS, the distribution of sulfur among the other FCC products depends on several factors, which include feed, catalyst type, conversion, and operating conditions. Feed type and residence time are the most significant variables. Sulfur distribution in FCC products of several feedstocks is shown in Table 2-4. Figure 2-9 illustrates the sulfur distribution as a function of the unit conversion. 

Effect of feed type on the gastrointestinal microbial ecosystem... 

Different EHEC serotypes are often found in ruminant populations, but most of the research to elucidate the effect of feed type on EHEC prevalence has been based on serotype 0157 H7. The preference for this pathogenic strain is due to its public health importance, its unique phenotypic characteristics that allow a relatively easy identification compared to other serotypes and the fact that ruminants are its most important natural reservoir. Shiga toxin-producing E. coli (STEC) are a larger group that includes EHEC and have also been found in ruminant populations in relatively large prevalence. Because the pathogenicity of most STEC has not been proven, we will focus our discussion on serotype 0157 H7. 

Technology Supplier Coal Feed Type Oxidant Gasifier Type... 

Table 84 CO conversion over 2.8%Au/ceria with temperature a space velocity of 51 500 h 1 ml per g cat434 as a function of feed type, with ...

Table 88 CO conversion over 30%Cu-l%Pd/ceria catalyst prepared by IWI of the metals at 210 °C as a function of feed type, using 4%CO, 10%CO2, C0/02 = 1/0.5, and CO/H20 = 1/10, balance H2 with 0.5 ml of catalyst438...

A summary of all feasible desalting options for Israel, subdivided according to the energy source, feed type and desalting technology is given in Table III ... 

Constraints (5.13) and (5.14) represent the material balance that governs the operation of the petrochemical system. The variable x 1 represents the annual level of production of process m Mpa where ttcpm is the input-output coefficient matrix of material cp in process m Mpel. The petrochemical network receives its feed from potentially three main sources. These are, (i) refinery intermediate streams of an intermediate product cir RPI, (ii) refinery final products Ff ri of a final product cfr RPF, and (iii) non-refinery streams Fn px of a chemical cp NRF. For a given subset of chemicals cp CP, the proposed model selects the feed types, quantity and network configuration based on the final chemical and petrochemical lower and upper product demand Dpet and DPet for each cp CFP, respectively. In constraint (5.15), defining a binary variable yproc et for each process m Mpet is required for the process selection requirement as yproc et will equal 1 only if process m is selected or zero otherwise. Furthermore, if only process m is selected, its production level must be at least equal to the process minimum economic capacity B m for each m Mpet, where Ku is a valid upper... 

Maximizing LCO yield is largely a bottoms management process. Recycle can be employed to fully maximize LCO at reduced conversion, while maintaining bottoms equal to that of a traditional maximum gasoline operation. Due to the lower conversion, coke yield is also reduced. Feed type, conversion level, recycle stream need to be chosen carefully to fully optimize the recycle operation. 

Feed Type HTVCO VCO + Sweet Reside Partially HT + Coker GO... 

Various sources estimate vitrification costs as ranging from under 100/ton to over 1000/ton for units treating hazardous waste. These estimates are assumed to be for treatment only, not including pretreatment and disposal costs. The extreme variability of the costs may be attributable to differences in feed type and water content of the waste (D18248T, p. 55). 

Another example of pheromone diversification occurs in the larch budmoth, Zeiraphera diniana, complex. The two species use ( )-9- and (E)- 1-tetradecenyl acetates as a pheromone, the larch-feeding type in a 100 1 ratio and the pine-feeding... 

The main processes marketed with this typical generic flow scheme reduce for example the sulfur content of a naphta feed type from 200-1000 ppm to between 0.5-1 ppm or less [61]. 

---