Plastic super

A packed absorption column removes an impurity from a gas stream by contact with a liquid solvent. The column is 3 ft in diameter and contains 25 ft of No. 2 plastic Super Intalox packing. The gas has an MW of 28, enters the column at 120°F, and leaves at 10 psig at a rate of 5000 scfm. The liquid has an SG of 1.15 and a viscosity of 0.8 cP. Determine ... 

Procetyl. [CiodaInc. CrodaChem.Ltd.] PPG cetyl ether compds. emollient coupler, cosolvent plasticizer, super-fatting, wetting arid spreading agent penetrant lubricant in cosmetics and personal care prods. 

Figure 10-24. Types of column packing (A) ceramic Intalox saddle, (B) plastic super Intalox saddle,...

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The overall height of a liquid-film transfer unit (Hql) is a function of the liquid flow rate and the temperature. The Hql for 2 plastic Super Intalox packing is 2.6 ft at a liquid rate of 40 gpm/ft and temperature of 68" F. The Hol increases as the water temperature is lowered. The Hql value varies with temperature for this packing as ... 

In this service, the Hql f 2 plastic Super Intalox packing is 2.8 ft at a liquid rate of 40 gpm/ft and a temperature of 68 F. The Hql value increases at lower water temperatures in the same manner as for water deaeration. Thus, Hql is 3.0 ft at 53°F and 3.2 ft at 41 °F at a liquid rate of 40 gpm/ft. The same investigators found that the height of a liquid phase transfer unit for CO2 stripping increased in a similar manner with liquid rate as for oxygen desorption [6]. At a liquid rate of 30 gpm/ft the Hql is 2.6 ft, while at a liquid rate of 53 gpm/ft the Hql is 3.0 ft for 2 plastic Super Intalox packing at a water temperature of 68°F. 

From these calculations, the use of the largest air rate will provide the lowest column cost for this application. The pressure drop through a 16.5-ft depth of 1 plastic Super Intalox packing will total only 3.0 in. H2O. The blower specified should deliver 1,500 CFM of air at an outlet pressure of 4 in. H2O. Thus, the operating power requirement will be small. 

Note Kca values apply to 2 plastic Super Intalox packing as a gas velocity of 3.5 ft/s and a liquid rate of 4 gpm/ft. ... 

Gas-film-controlled systems normally have higher Koa values than liquid-film-controlled systems. Table 5-4 shows the base K a values for typical gas-film-controlled systems at 3.5 ft/s superficial gas velocity and 4 gpm/ft liquid irrigation rate [5]. These values apply for 2 plastic Super Intalox packing and for liquid temperatures from 60° to 75°F. The packed depth required for other tower packings is a function of the ratio ... 

Kq2l value for 2 plastic Super Intalox packing to KqZ. value for the packing selected as shown in Table 5-5. The packed depth required also is inversely proportional to the relative KqS. values corrected for liquid rate, as given in Table 5-6. 

Because this is a liquid-film-controlled system, the small gas rate effect is not significant in these graphical calculations. Using Figure 5-2, the packed depth required for 96% HCHO removal at a gas rate of 5.0 ft/s is 30.2 ft for 2 plastic Super Intalox packing. For the UA-in. plastic Pall rings, the bed depth can be corrected by factors taken from Table 5-5. 

Because of the relatively small air flow, the column diameter normally will be selected to provide a liquid irrigation rate between 15 and 40 gpm/ft. Next, the height of a transfer unit must be determined for the tower packing chosen. It has been found that the mass transfer coefficients for stripping trichlorethylene, perchlorethylene, chloroform, and carbon tetrachloride are the same [17]. The Hql fnr 1 and 2 plastic Super Intalox packing is 3.2-ft and 4.7-ft, respectively, at a liquid rate of 30 gpm/ft. Tests conducted by the EPA in 1984 (stripping aromatics from water) and in 1987 (stripping TCE and PCE from water)... 

Because the bed depth will not be excessive, 2 plastic Super Intalox packing has been selected for this stripping column. Because of the large amount of water evaporated from the 140°F feed liquid, the vapor rate at the top of the column is greater than at the bottom. A 36-in. ID tower is needed to restrict the pressure drop to a maximum of 0.40 in. H2O/ft. At the operating liquid rate of 12.5 gpm/ft, we should obtain a 3.81 ft Hql value thus, a 26.5 ft depth of pacing is required. As the exit air contains almost 20% water vapor, if this gas stream is to be incinerated, a gas cooler/condenser may be desired to reduce the water content of the gas. 

A = data for 2 plastic Super Intalox paddng, gas velocity 3.5ft/s, liquid rate 10 gpm/sqft. (ASHRAE Handbook. 1988)... 

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