00063 02686TSFlV 01448Ts 0008Ffv

Figure 5 Sieve tray design procedure.

In this equation FlV = (L/V)(pV/pL)0'5, TS is tray spacing in feet, and L and V are mass flow rates of the liquid and vapour. The CSB is valid for trays with a fractional hole area greater than 10%. For areas of 8 % and 6%, Csb should be multiplied by 0.9 and 0.8, respectively.

Knowing UN,f and the total vapour flow rate, the column diameter can be calculated by assuming that the column will be operated at a lower vapour velocity, say 80% of the flood point.

Number of Flow Passes

The number of flow passes is set to allow the tray to operate at a weir loading that does not result in excessive weir crest. The weir loading can be calculated once the column diameter and the down-comer area are determined. The optimum weir loading is 4-6 US gallons per minute and the maximum loading is about 20. Downcomer choking, which causes liquid build-up on the tray, may occur if the maximum value is exceeded. Increasing the number of flow passes provides a solution to this problem (see Figure 2). However, shorter liquid flow path and possible maldistribution of liquid and vapour streams in multipass trays may result in lower tray efficiency.

As a rule of thumb, the liquid and vapour handling capacity are a direct function of weir loading and column area, respectively. Since weir length and column area are proportional to column diameter and diameter squared, respectively, the use of multipass trays is often necessary for large-diameter columns.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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