Slurry Flow Rate

A small re-circulation pipeline loop was used for measuring the slurry flow parameters. A test section consists of three stainless steel pipes of inner diameter D = 10.5, 17.5 and 26.8 mm. The length/diameter ratio of the test section for each pipe diameter was 300, 400 and 260, respectively. The slurry was forced to pipe by a screw pump with speed regulator from an open storage tank, equipped with an agitator to prevent slurry settlement. All pipes used in the test section could be considered as smooth pipes. Measuring section of the loop was equipped with three pressure tapings connected to differential pressure transducers. Box divider at the pipe outlet allowed direct volumetric measurement of the flow rate, slurry density and concentration, Chara et al [5]. 

Thickening Pressure Filters. The most important disadvantage of conventional cake filtration is the declining rate due to the increased pressure drop caused by the growth of the cake on the filter medium. A high flow rate of Hquid through the medium can be maintained if Httle or no cake is allowed to form on the medium. This leads to thickening of the slurry on the upstream part of the medium filters based on this principle are sometimes called filter thickeners. 

Measurement by Electromagnetic Effects. The magnetic flow meter is a device that measures the potential developed when an electrically conductive flow moves through an imposed magnetic field. The voltage developed is proportional to the volumetric flow rate of the fluid and the magnetic field strength. The process fluid sees only an empty pipe so that the device has a very low pressure drop. The device is useful for the measurement of slurries and other fluid systems where an accumulation of another phase could interfere with flow measurement by other devices. The meter must be installed in a section of pipe that is much less conductive than the fluid. This limits its appHcabiHty in many industrial situations. 

Fig. 17. Heat-transfer coefficient comparisons for the same volumetric flow rates for (A) water, 6.29 kW, and a phase-change-material slurry (O), 10% mixture, 12.30 kW and ( ), 10% mixture, 6.21 kW. The Reynolds number was 13,225 to 17,493 for the case of water.

Fig. 24. Flow meters for on-line measurement of slurry flow rates (a) magnetic and (b) ultrasonic (6).

The function of clear-Hquor advance can be illustrated by considering a simple operation, shown in Figure 13, in which Qcv < 0 volumetric flow rates of clear-Hquor fed to the crystallizer, in the clear-Hquor advance, and in the output slurry. In such systems the population density function is given by the expression... 

Another important objective which must be considered is to provide adequate cyclone capacity for the application. The volume of feed slurry that a given cyclone can handle is related to the pressure drop across the cyclone. The relationship between flow rate and pressure drop for several different sizes of standard cyclones is shown in Figure 56. As shown, the flow rate increases as the pressure drop increases. In order to utilize this graph, the pressure drop used for calculating the separation is used to determine the flow rate for the cyclone diameter which was... 

W = Mass flow rate of slurry through tank, Ib/hr Cp = Heat capacity of slurry, Btu/(lb ,) (°F)... 

Slurry is pumped and fills the ehambers at a high flow rate and low pressure whieh gradually builds-up as the eake gets thieker. The drip trays whieh are positioned below the filterpress for the eolleetion of drippings elosed. 

Slurry is pumped and fills the chambers at a high flow rate and low... 

The precipitate that forms during ozonolysis sometimes impedes stirring, and in some cases it may be necessary to dilute the slurry with another 100 ml. of methanol after the first hour. Solid can also clog the gas-dispersion tube. The submitters scraped the fritted-glass tip occasionally to maintain a constant flow rate, whereas the checkers prepared a more dilute solution of nitronate anion (Note 3). 

Bubble-column slurry operations are usually characterized by zero net liquid flow, and the particles are held suspended by momentum transferred from the gas phase to the solid phase via the liquid medium. The relationships between solids holdup and gas flow rate is of importance for design of bubble-column slurries, and some studies of this aspect will be reviewed prior to the discussion of transport phenomena. 

One to 5 g material was mixed by a glass rod with 1 mL/g material of "stopping solution", that contained 25 mg/mL of ammonium sul-famate, 25 mg/mL of sodium ascorbate, and 2.0-2.5 mg/mL of cis-2,6-dimethylmorpholine (cis-DMM), and was adjusted to pH 1 with H2S0. The pH of the slurry was readjusted to 1 with concentrated H2S0. The mixture was stirred with 10 g Celite 560 (from Johns Manville Corp. previously sifted to remove< 60 mesh particles), and packed dry in a "Monoject" plastic 50 mL syringe barrel (Shermwood Industries) prepacked with 8 g Celite. The column was eluted (without flow-rate control) with 100 mL... 

Mass transfer-limited processes favour slurry reactors over monoliths as far as the overall process rates are concerned. Moreover, slurry reactors are more versatile and less sensitive to gas flow rates. However, the productivity per unit volume is not necessarily higher for slurry reactors because of the low concentration of catalyst in such reactors. There also is no simple answer to the selectivity problem, and again, each process should be compared in detail for both reactors. 

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