Feed distributor

For columns that are wider than several centimeters, reflux and feed distributors should be used, particularly for wet foam [Haas and Johnson, Am. Jn.st. Chem. Fng. J., 11, 319 (1965)]. Liquid content within the foam can be monitored conduc tometricaUy [Chang and Lemhch, J. Colloid Jnteiface Sci., 73, 224 (1980)]. See Fig. 22-44. TheoreticaUy, as the limit =K = 0is veiy closely approached, 2] = 3K [Lemhch,y. Colloid Jnteiface Sci, 64, 107 (1978)]. 

Running unbal- Redesign feed distributor anced—vibration. different bowl speed (usually slower) due to uneven feeding effective vibration monitor/shutdown device Adjust feed rate to get uniform distribution ... 

Added a feed distributor (omitted originally) to allow the proper lower feed point to be used for one feed stream. 

FIG. 23-50 Feed distributor devices for horizontal blowdown drums/catch tanks. (Guidelines for Pressure Relief and Effluent Handling Systems, Center for Chemical Process Safely (CCPS) of the American Institute of Chemical Engineers (AlChE) copyright 1988 AlChE and reproduced with permission.). 

Vapor-Liquid Gravity Separator Design Fundamentals The critical factors in the performance of a horizontal separator are the vapor residence time and the settling rate of the liquid droplets. However, two other factors enter into the design—the vapor velocity must be limited to avoid liquid entrainment, and there must be sufficient freeboard within the vessel to allow for a feed distributor. For vertical separators, the design is based on a vapor velocity that must be less than the settling velocity of the smallest droplet that is to be collected, with due allowance for turbulence and maldistribution of the feed. The vapor residence time is a function of the vapor flow rate (mass), vapor density, and volume of vapor space in the separator, based on the following ... 

Open area of chimney feed distributor = 40 percent... 

Use of efficient olefin feed distributors is also effective in reducing acid consumption. The conditions at the point of initial olefin contact with the circulating catalyst are very important because of the extremely rapid rate of the initial reaction. Perforated sparger rings are frequently employed, and a concentric feed nozzle is also a common feature 6). 

When faced with a packed tower, always keep in mind that packing involves an entire system, not just some mass-transfer surface. Packed towers include packing supports, packing, packing hold-down, feed distributors, internal redistributors, and other equipment. Fig. 1 shows a generic packed tower system. 

Figure 285. Vintage (1919) drawing of a Koppern roller press with two rings and mechanical feed distributor. (Courtesy of Koppern, Hattingen, FRG) ... 

Feed distributors should be located at least 8 in above the tray floor for liquid feeds, and at least 12 in above the tray floor for flashing feeds (207). A distributor of the type shown in Fig. 2.2, arrangement i, is best located so that its centerline is two-thirds of a tray spacing above the tray floor (207). 

The main consideration for introducing reflux or intermediate feed into a packed tower is adequately distributing the incoming stream to the packing. Unlike most tray columns, packed towers are sensitive to distribution. Maldistribution is detrimental to packing efficiency and turndown. The main devices that set the quality of distribution in a packed column are the top (or reflux) distributor, the intermediate feed distributor, the redistributor, and sometimes the vapor distributor. Adequate hydraulics in the inlet area is also important failure to achieve this can affect distributor performance and can also cause premature flooding. 

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