Vapour Distribution Requirements

Vapours entering the tower have a kinetic energy proportional to their velocity, which is converted into pressure as the vapour turns to start flowing upward in the tower. The resulting radial pressure profile is not uniform; areas of higher pressure would allow higher vapour up-flow. This is especially critical for low-pressure drop packings such as structured packings. Vapour radial velocity profiles are corrected by pressure drop and by diffusion devices. The following is the recommended practice for vapour distribution:

• Low vapour inlet velocity (velocity head below 0.5 inches of water): no inlet distributor required, provide as minimum column diameters, or 36 inches between the top of the vapour inlet nozzle and the bottom of the bed.

• Intermediate vapour inlet velocity (velocity head between 0.5 and 1.5 inches of water): provide an inlet vapour diffuser directing vapour flow down the tower. This type of device can be a horizontal pipe with the bottom half cut as shown at the bottom of the column in Figure 2. Vertical baffles can be provided for better vapour distribution. The purpose of these baffles is to stop the horizontal velocity component of the vapour.

• High vapour velocity (velocity heads above 1.5 inches of water): provide an inlet vapour diffuser, as described above, plus a small riser chimney tray with a pressure drop of a minimum of 2 inches of water. The pressure drop can be created by orifices at the bottom of the risers. A vapour distributor, as shown in Figure 12 is a good alternative to the vapour diffuser in critical systems.

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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