Profiled bottom tank

Chudacek, M.W. Impeller power numbers and impeller flow numbers in profiled bottom tanks. Ind. Eng. Chem. Des. Dev. 1985, 24, 858-867. 

Chudacek M.W., Solids Suspension Behaviour in profiled bottom and flat bottom mixing tanks, Chem. Engng. 

The rate of discharge of water from a tank is measured by means of a notch for which the flowrate is directly proportional to the height of liquid above the bottom of the notch. Calculate and plot the profile of the notch if the flowrate is 0.01 m3/s when the liquid level is 150 mm above the bottom of the notch. 

The results in terms of the amount and composition in the condenser holdup tank and in the bottom product accumulator are presented in Tables 4.11 and 4.12 respectively. The condenser holdup tank and bottom product accumulator composition and reboil ratio profiles are shown in Figures 4.13 and 4.14 respectively. 

Also 1.52 kmol of product C with an accumulated composition of 0.70 molefraction was obtained in the distillate tank. Figure 4.18 shows the accumulated distillate, feed tank and bottom product composition profiles for the operation and Figure 4.19 shows the holdup profiles in the distillate accumulator, feed tank and bottom product accumulator. 

The test sections are equipped with a radioactive counting station using sodium iodide detectors about two thirds up from the bottom of the tube. It is considered that after approximately this distance the velocity profile will have been established. The length after the counting station is included to avoid any interference by the exit of the liquid from the tube. After passing through the test section, liquid can be directed to either of the feed tanks or into the glass vessel (for flow measurement). Fig. 17.4 shows data obtained from the test apparatus [Williamson 1990],... 

For the first run, 4.5 liters of dlstllled-mllllpore water were measured Into the process tank. Twenty-five grams of PEO and 25 gms. of PVA were slowly added to the water and dissolved. A 197.2 ppm Internal standard solution of methanol In water was made In a one liter round bottom flask and set In a cool place. The gas chromatograph was started up and the calculation program was entered. When the polymer had dissolved, 500 ml of heptane were added under shear to the process tank. The contaminant solution was made In the feed tank by dissolving 10.0 ml of toluene In 18.9 liters of water. A lid was placed on this tank to limit vapor losses. The process tank was preloaded with 25.0 ml of toluene and the lid was secured. The appropriate valves were opened, and the process and feed ptimps started. The permeate was returned to the process tank until the pressure profile was established. Once this was achieved, the permeate was drawn off and Its flowrate measured. The contaminant flowrate was then set equal to the permeate rate and both were continuously monitored throughout the experiment. The temperature of the process tank was measured and the coolant temperature setpoint and flowrate were adjusted until the steady state condition was obtained. Six one-mllllllter samples were taken periodically from the feed, permeate, and process tank. The clear feed and permeate samples were capped Immediately and labelled. The mllky-whlte... 

The column liquid composition profile at the end of each operating step can be seen in Figure 13.7. Notiee that there is no methanol in the upper rectifying section at the end of Step 1 (time = 3.17 h). This is due to the continuous feeding of the entrainer into the column to push the methanol to appear only in the lower extractive section of the column. At the end of Step 2 (time = 5.34 h), the column composition profile has moved from the acetone comer toward the methanol comer. The top Uquid composition is close to the methanol comer at the end of Step 3 (time = 8.48 h). At this time, there is almost no acetone inside the column, so the separation is just like regular batch distillation. At the end of Step 4 (time = 12.26 h), the methanol pmity in the P2 product tank can no longer be maintained at its specification. At the same time, the bottom product has already satisfied the water purity specification. The column is shut down and the bottom product is collected. 

In the present work, two thermocouple rakes are utilized—one installed vertically in the center of the vessel, and the other fastened to the side wall—capable of sensing horizontal temperature profiles from 0 to 11 in. from the wall at three distinct levels (approximately 17, 49, and 56 in. from the tank bottom, respectively). Figure 1 illustrates the location of each thermocouple in the vertical direction. 

In general, average temperature-measuring elements are used in case of temperature stratification. The latest development is the multitemperature thermometer (MTT) shown in Fig. T-26 that utilizes 16 thermosensors evenly distributed over the maximum possible liquid height. A very accurate class A PtlOO element at the bottom is the reference. Accuracies of better than 0.05°C (0.08°F) are possible. The elements can also be individually measured to obtain temperature profiles and vapor temperatures. MTTs are available with both nylon and stainless steel protection tubes. It provides a rugged construction suitable for the harsh environments of a bulk storage tank. 

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