Packed columns plastic

Next, to determine packed column height use Table 9 for distillation HETP values, leaning tow ards the high side of the range for studies. For use of Kqa values see Section A—Absorbers. Bed height per packed bed runs up to 20-30 ft for metal or ceramic packings, but plastic packing is usually limited to 24 ft. 

Packed columns of glass beads, glass spirals, or fibres Plastic packing also feasible in some... 

A packed column is used to scrub S02 from air by using water. The gas flow rate is 500 scfm/ft2, and the column operates at 90°F and 1 atm. If the column contains No. 1 plastic Intalox packing, what is the maximum liquid flow rate (per unit cross section of column) that could be used without flooding ... 

The vast majority of analyses use long, narrow open tubular columns (Figure 24-2) made of fused silica (Si02) and coated with polyimide (a plastic capable of withstanding 350°C) for support and protection from atmospheric moisture.3 As discussed in Section 23-5, open tubular columns offer higher resolution, shorter analysis time, and greater sensitivity than packed columns, hut have less sample capacity. 

The main factors favoring packed columns are (1) very corrosive applications, where plastic or ceramic packings are favored over trays, which are almost always constructed of metal (2) low pressure drop requirement, which is easier to achieve with packings than with trays (3) small-diameter columns, because trays require access for inspection and maintenance and (4) foaming systems, which are easier to handle in packed towers. 

From a healthy volunteer 200 ml blood is collected. An aliquot of 8.4 ml blood is mixed with 1.4 ml ACD-buffer in polystyrol tubes and centrifuged at 1000 rpm for 15 min. The resulting platelet-rich plasma (PRP) is collected and an aliquot is taken for platelet counting. Ten milliliters of PRP are mixed with 1 ml ACD-buffer (ACD-PRP, pH 6.5) 5 ml portions of ACD-PRP are transferred to plastic tubes and centrifuged at 1600 rpm for 20 min. The resulting supernatant is decanted, and each pellet is resuspended in 500 pi Tyrode buffer C. An aliquot is taken for platelet counting to calculate the loss of platelets. The platelet suspension is then transferred to the Sepharose-packed column which... 

S. L. Secreast, unpublished application. Packed-column supercritical fluid chromatography of plastics additives. Pharmacia Study Report, 1996. 

Packed tower aeration (PTA), also referred to as packed column aeration (PCA), is a waterfall aeration process that trickles water down through and air flow up through plastic... 

Where not otherwise stated in Tables 1-5, the stillage is 0.4 percent, the feed 8 percent and the product 90 percent ethanol by weight. Energy is in BTUs per pound product, while diameter is for 50 gallon-per-hour feed with a packed column using plastic Intalox saddles for packing. 

A wastewater stream of 0.038 m3/s, containing 10 ppm (by weight) of benzene, is to be stripped with air in a packed column operating at 298 K and 2 atm to reduce the benzene concentration to 0.005 ppm. The packing specified is 50-mm plastic Pall rings. The airflow rate to be used is five times the minimum. Henry s law constant for benzene in water at this temperature is 0.6 kPa-m3/mol (Davis and Cornwell, 1998). Calculate the tower diameter if the gas-pressure drop is not to exceed 500 Pa/m of packed height. Estimate the corresponding mass-transfer coefficients. The diffusivity of benzene vapor in air at 298 K and 1 atm is 0.096 cm2/s the diffusivity of liquid benzene in water at infinite dilution at 298 K is 1.02 x 10 5 cm2/s (Cussler, 1997). 

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