Slurry concentration meter

When starch is added to cold water (below 29°C, 85°F), only negligible swelling will occur. However, the suspension volume expands, since the insoluble starch replaces water. Addition of starch to water at a concentration of 10% will increase the volume by 13%. The maximum in suspension solids is 40-45%. Various methods are used to determine the solids content of the starch slurry aerometer,92 density cells, densitometer, attenuation of vibration (Dynatrol) or a radiation-type density meter. Concentrated starch slurries have high viscosity and shear thickening (dilatent) rheology. Settling of starch from the slurry produces densely packed sediments that are difficult to disperse. 

Coal Concentration, wt.% Slurry Velocity by Diversion, m/s Ultrasonic Parallel, m/s Cross-correl. Crossed, m/s Meter Factor Parallel Crossed Geometry Geometry ... 

Ultrasonic Flowmeters. Ultrasonic methods have been used to measure flow velocity and concentration in slurry pipelines (22) and emulsion pipelines (65). There are three methods of ultrasonic flow meter applications transmission of ultrasonic wave, beam deflection, and frequency shift method (22). The frequency shift method (the ultrasonic Doppler flowmeter) consists of a transducer and an electronic control box. The transducer is either clamped on the outside of the pipe or inserted into the pipe so that it is flush with the inside of the pipe wall. The transducer comprises the sensors to transmit and receive the Doppler signal. These sensors are either in a single transducer or in two separate transducers. The control box processes transmitted and received signals (Figure 25). 

Figure 8. Schematic drawing of the coal slurry concentration meter.

The development status of process control instrumentation lags that of the quality control instruments significantly Nuclear density gauges function in the coal preparation plant environment The slurry concentration meter has application in the intermediate and fine sized coal cleaning circuits and needs to be tested in a preparation plant Other devices, such as ash monitors to control the operation of heavy media baths or jigs are not available and instruments developed for other process industries are not suitable for use in coal preparation plants Modeling studies of the various unit operations are required in order to ascertain the fundamental parameters required to automate the control of these systems Primary process control instrument needs include ash, sulfur, and moisture monitors secondary needs include an on-line washability and ash fusion measurement ... 

Steeping. Sheet, roU, or suitably milled flock pulp is metered into a pulper along with vigorously stirred 18% sodium hydroxide solution at 50°C. The resulting slurry, containing about 5% finely dispersed pulp, passes to a buffer tank from which it is metered to a slurry press that sieves out the swollen fiber and returns the pressings soda for concentration correction and reuse. The cellulose reacts with the soda as a complex alcohol to form the sodium salt or alk-ceU. 

Carboxymethylcellulose slurry (equivalent of 75 g of dry material)—Slowly wet 75 g of dry resin in distilled water. Draw off the supernatant (after the resin has settled) with vacuum filtration. Resuspend the filtered resin cake in 1.5 L of 0.5 M NaOH (30 g of NaOH dissolved in 1.5 L of distilled water). Allow the resin to settle, draw off the supernatant, and wash the resin cake twice, as before, in 2.5 L volumes of distilled water. Resuspend the resin cake in 2.5 L of 0.5 M HC1 (100 ml of concentrated HC1 in 2.4 L of distilled water). Allow the resin to settle, draw off the supernatant, and wash the resin cake twice, as before, in 2.5 L volumes of distilled water. Repeat the wash procedure described above with 1.5 L volumes of 0.03 M sodium acetate buffer, pH 5.0, until the pH and ionic strength of the drawn-off supernatant is the same as that of the sodium acetate buffer (pH and conductivity meter). Resuspend the resin cake in 1.5 L 0.03 M sodium acetate buffer, pH 5.0. Add 2 g/liter sodium azide for storage to prevent bacterial growth. Remove the azide by washing again in 0.03 M sodium acetate buffer, pH 5.0 when it is ready to be used by the class. 

In the above method, an autotitrator repeatable to +0.5% relative error (or 0.01 wt%) was employed to measure H2O2 wt%, independent of the relative amounts of DI water and slurry. A densitometer with an accuracy of + 0.0005 g/cc was used to estimate the percentage volume of slurry in the mixture (repeatability = +3% slurry by volume), for a specific concentration of H2O2. In the above blend, the measured H2O2 wt% concentration was used to control the speed (or strokes/batch) of the W2000 slurry pump, whereas the density, obtained using a coriolis mass flow meter, controlled the speed of the DI water pump. On the basis of the property curves obtained from bench... 

The feed materials are manufactured and shipped at paint solid concentrations ranging from 40% to 99+%. In some installations, the feed is metered into the tank in the form of two or more components, one component being the resin, the other component being a pigment slurry, etc. 

F. Repeat-dose activated charcoal. Repeated doses of activated charcoal (20-30 g or 0.5-1 g/kg every 2-3 hours) are given orally or via gastric tube. The presence of a slurry of activated charcoal throughout several meters of the intestinal lumen reduces blood concentrations by intermpting enterohep-atic or enteroenteric recirculation of the dmg or toxin, a mode of action quite distinct from simple adsorption of ingested but unabsorbed tablets. This technique is easy and noninvasive and has been shown to shorten the half-life of phenobarbital, theophylline, and several other dmgs (Table 1-41). However, it has not been shown in clinical trials to alter patient outcome. Caution Re-peat-dose charcoal may cause serious fluid and electrolyte disturbance secondary to large-volume diarrhea, especially if premixed charcoal-sorbitol suspensions are used. Also, It should not be used in patients with ileus or obstmction. 

In the specific example described, the reaction tank 10 has a volume of about 3 cubic meters and contains 1 gm. Pu per liter D2O. This concentration of plutonium in heavy water in the reaction tank 10 having the dimensions previously mentioned, will support a sustained chain reaction therein independently of any neutrons supplied from outside the reaction tank and re rdless of the amount of thoria contained by the slurry. This 94 3 can be dissolved in the moderator in the form of a salt such... 

Currently, site-specific tests are often conducted to estimate the consumption and effects of additives (Moser and Owens, 1991). Some significant major process variables to examine when considering use of an additive are additive concentration, pH of the absorber feed slurry, and dissolved calcium concentration (Moser et al., 1990). Other important factors to consider in additive use are pH meter maintenance and opmtion, thickener operation, absorber and mist eliminator plugging, foaming (caused by soap-like impurities) in the recirculation tanks, system water balance, and corrosion of the additive feed system (Babcock Wilcox, 1992B). 

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