(189e) A New High Capacity Gas Distributor-Cum-Support PLATE for Packed Columns

New designs of a packed column support plate cum gas distributor are presented which permit working of the column at low or high gas flows and at the same time do not allow seepage of liquid into the gas flow chambers. The designs presented in Fig. 1(Device 1) and Fig. 2(Device 2) fulfill the above criteria. The design presented in Fig. 2 (Device 2)has an added advantage of lower plate pressure drop and higher capacity than the one offered by Device 1 .

DETAILED DESCRIPTION OF THE INVENTION

Description of Device 1 : The packed column setup used for hydraulic studies consists of a 140mm diameter column The column is made of perspex and in multiple sections, so that the packed bed height could be varied. The support plate was designed to provide only the following:

• Mechanical support to the packing
• Uniform gas distribution across the column cross-section
• Separate flow paths for the gas and liquid streams

The support/collector plate, as shown in Figure 1 is a small column section of 100mm height. It consists of 16 nos. of evenly distributed 12 mm ID gas risers, which correspond to a riser area equal to 12% of column area. It has 5 nos. liquid drip tubes of 12mm ID. Air enters the support plate chamber through a 1in diameter sparger pipe having 48 nos.of 4mm diameter holes. A cap on each riser was provided to prevent liquid seepage through gas entry nozzles.

Figures 2 and 3 show the design of new support plate device 2 which consists of rectangular gas risers containing horizontal slots (for gas flow) having open area equal to column cross sectional area to ensure the smooth expansion of gas while leaving the support plate (just before the entering of bed). Figure 4 shows the data on bed pressure drop vs air flow rate for a liquid flow rate of 10 lpm and bed height equal to 420 mm obtained by using support plate device 2 and IMTP #15 packing as well as Mellapak 350Y packing. A comparison of the results obtained for the two packing types shows that Mellapak 350 Y gives higher flooding velocity than IMTP#15.Figure 5 shows data on bed pressure drop as a function of air flow rate for different bed heights using IMTP#15 packing and device 2 as support plate. A comparison of the results obtained by using different bed heights shows that with increase in bed height the flooding velocity increases substantially. Figure 6 shows a comparison of the pressure drop data as a function of gas flow rate and for a liquid flow rate of 10 lpm obtained with the two support plate devices and IMTP #15 packing which shows that device 2 gives much lesser pressure drop than device 1 and also gives higher gas handling capacity than device 1. Device 1 is expected to be useful when the gas rates are low and liquid should not seep into the gas entry compartment. Device 2 performs much better than Device 1 from the point of view of high flooding velocity that is attainable with the former at a pressure drop much lower compared to the pressure drop obtained with Device 1.