Separation capacity pressure losses

The separation capacity, pressure losses and energy consumption are the most important parameters of separators, and these can help to establish relevant characteristics for the choice and evaluation of separators. They are dependent on a number of factors, of which the following are the most important dirty gas inlet flow rate, its composition and conditions concentration of the particles in the gas together with their physical and chemical characteristics and the operating regime of the separator. 

As the filter accumulates dust, the pressure loss increases, and the dust removed improves the normal separation. Another effect can be seen with electrostatically charged filter material. During operation, the impurities neutralize the material, and the filter s capacity to separate is reduced. Figure 9.3" shows exam-... 

The backpres.sure created by this drum is an additive to the pipe manifold pressure drops and the pressure loss through the separator. Therefore, it cannot be independently designed and not integrated into the backpressure system. The flow capacity of the relief valve(s) must... 

The volume flow in a typical miniplant is of the order of 101 h 1. The limiting factor is the gravity-driven flow in the separation units, for example, a rectification column. As separation units usually accompany a chemical process, this flow limit dominates the overall capacity of a miniplant. It is surprising that the flow rate is not limited here by the pressure loss. 

The right half of Fig. 14.23 shows the dependence of power consumption per unit separative capacity QfL on the same pressure variables. The power consumption has been calculated as the rate of loss of availability, so that g/A is given by... 

An ideal filter of highest value of filter quality coefficient means that it has the maximum separation capacity with minimum pressure loss, and these two parameters remain constant during the service life of filter. The major criteria of the performance of a filter include filter efficiency, pressure drop, and the filter quality performance. ... 

For a high-temperature system, a separate subheader may be run up to the point where the temperature drops down to the allowable limit of a less expensive material. It may then be connected to the main flare header (either low pressure or high pressure).To properly evaluate this a heat loss calculation is needed. As a rule of thumb a heat loss of 10 BTU/hr/ft may be assumed for a quick estimate for bare pipe. Consideration should also be given to the need for expansion joints. Main flare headers may be as large as 36 to 42 inches in diameter for a large-capacity plant. Expansion joints of such magnitudes may be so expensive as to call for a separate small header for the hot flare system. 

For the separation of such batteries, gel construction and microfiber glass fleece separators again compete because of the deep discharge cycles, the gel construction with its lower tendency to acid stratification and to penetration shorts has advantages for the required power peaks, microfiber glass fleece construction would be the preferred solution. The work on reduction of premature capacity loss with lead-calcium alloys has shown that considerable pressure (e.g., 1 bar) on the positive electrode is able to achieve a significantly better cycle life [31-36], Pressure on the electrodes produces counter pressure on the separators, which is not unproblematic for both separation systems. New separator developments have been presented with... 

Mercerizing Liquors.—Quantities of liquor will vary considerably with the process of washing used in each plant, and a reasonable average will give 2 gal. of 6°Twaddell waste liquor for each pound of cotton mercerized. These liquors are usually concentrated to from 70 to 80 Twaddell in a triple- or quadruple-effect evaporator of the horizontal-tube or rapid-circulation type. The capacity is from 2H to 3H gal. per square foot, with a steam pressure of from 10 to 15 lb. Special construction and entrainment separators are necessary to prevent losses by foaming. The last effect will frequently show incrustations of sodium carbonate which can be dissolved in hot water or weak hquor. Evaporators are usually built of steel with steel or charcoal-iron tubes. 

Another feature of AGM separators is their compressibility. With compression of the plate and separator stack, this AGM property guarantees good plate-separator contact, even if the plates are not perfectly smooth. Also, battery assembly is facilitated since the stack can be easily inserted into the cell after compression to a thickness lower than the cell dimension. An undesirable result of the compressibility is that the AGM separator does not exert sufficient resistance against expansion of the positive plate during battery cycle-life. This expansion is particularly prevalent in deep-cycle applications and can cause the battery to suffer premature capacity loss (PCL) via reduced inter-particle conductivity — a phenomenon known as PCL-2 [7]. In the literature, two additional characteristics, which are related to the PCL-2 failure mode, are discussed, namely, AGM separators shrink when first wetted with electrolyte and their fibres can be crushed at high pressure levels [8-10]. These features result in a loss of separator resilience, i.e., a lessening of the ability to display a reversible spring effect. 

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