Water washing

Bomb Method the sample is burned in a bomb under oxygen pressures of 30 bar. The sulfur contained in the wash water is analyzed via gravimetry as barium sulfate. 

The treated water containing sodium chloride, cyanides, phenols and traces of H2S and NH3 is recycled to the crude desalting unit and used as wash water for the hydrotreaters and FCC units. 

MP-suspension by automated ASTM-bulb Magnetization current by Hall-Sensor Magnetization time UV-Light intensity All Liquids (fluorescence, contamination) Process times and temperatures Function of spraying nozzles, Level of tanks Flow rates (e.g. washing, water recycling) UV-Light intensity... 

Add 25 g. of finely-powdered, dry acetanilide to 25 ml. of glacial acetic acid contained in a 500 ml. beaker introduce into the well-stirred mixture 92 g. (50 ml.) of concentrated sulphuric acid. The mixture becomes warm and a clear solution results. Surround the beaker with a freezing mixture of ice and salt, and stir the solution mechanically. Support a separatory funnel, containing a cold mixture of 15 -5 g. (11 ml.) of concentrated nitric acid and 12 -5 g. (7 ml.) of concentrated sulphuric acid, over the beaker. When the temperature of the solution falls to 0-2°, run in the acid mixture gradually while the temperature is maintained below 10°. After all the mixed acid has been added, remove the beaker from the freezing mixture, and allow it to stand at room temperature for 1 hour. Pour the reaction mixture on to 250 g. of crushed ice (or into 500 ml. of cold water), whereby the crude nitroacetanilide is at once precipitated. Allow to stand for 15 minutes, filter with suction on a Buchner funnel, wash it thoroughly with cold water until free from acids (test the wash water), and drain well. Recrystallise the pale yellow product from alcohol or methylated spirit (see Section IV,12 for experimental details), filter at the pump, wash with a httle cold alcohol, and dry in the air upon filter paper. [The yellow o-nitroacetanihde remains in the filtrate.] The yield of p-nitroacetanihde, a colourless crystalline sohd of m.p. 214°, is 20 g. 

The number of washings may be reduced to about twenty, if time is allowed for diffusion of the alkali from the surface of the catalyst into the surrounding wash water. Use 750 ml. of water in each washing, allow diffusion to proceed for 3-10 minutes, stir again, and decant the supernatant liquid as soon as the catalyst settles to the bottom. 

This experiment describes the use of a fractional factorial design to examine the effects of volume of HNO3, molarity of AgN03, volume of AgN03, digestion temperature, and composition of wash water on the gravimetric analysis for chloride. 

Fig. 7. Mercury cathode electroly2er and decomposer (11) 1, brine level 2, metal anodes 3, mercury cathode, flowing along baseplate 4, mercury pump 5, vertical decomposer 6, water feed to decomposer 7, graphite packing, promoting decomposition of sodium amalgam 8, caustic Hquor exit 9, denuded mercury 10, brine feed 11, brine exit 12, hydrogen exit from decomposer 13, chlorine gas space 14, chlorine exit 15, wash water.

Picric acid may be made by gradually adding a mixture of phenol and sulfuric acid at 90—100°C to a nitration acid containing a small excess of nitric acid. The picric acid crystals are separated by centrifugiag, washed, and dried. The wash water is reused to decrease losses owiag to the water solubiUty of the picric acid. A yield of about 225% of the weight of phenol is commonly obtained. 

The transport of phthalates by road tankers and ships within Europe is carried out by international companies with sophisticated tank cleaning facihties. Wash waters from these modem faciUties are passed through a series of separators to remove any residual plasticizer which is then incinerated. It is estimated that, as a result of cleaning and spillages, the maximum emission to the environment is 80 t/yr. 

The resulting nitrous oxide can be recirculated to the nitric acid plant or be used for other purposes. Free acid remaining in the impregnation water of sodium nitrate crystals is neutralized by adding some NaOH to the washing water. Whereas several nitric acid plants utilize absorption of nitrous gases to treat tail gases, almost all of these plants produce small volumes of sodium nitrate. 

Microstrainers. Microstrainers are rotating steel screens with extremely fine stainless steel mesh (85—170 perforations per square centimeter (13—26/in. )). The flowing Hquid enters the open end of the dmm and passes through the mesh to the effluent end. The mesh traps soHd impurities and rotates with the dmm. A wash-water spray washes the trapped soHds into a hopper for final disposal. The mesh is washed with filtered effluent discharged from jets fitted into the dmm and then exposed to uv radiation to inhibit microbial growth. The mesh is washed with chlorine water at intervals of 7 to 28 days in order to control slime growth removal efficiencies are 30—55% of the appHed BOD and 40—60% of suspended soHds. 

Extraction of Bertrandite. Bertrandite-containing tuff from the Spor Mountain deposits is wet milled to provide a thixotropic, pumpable slurry of below 840 p.m (—20 mesh) particles. This slurry is leached with sulfuric acid at temperatures near the boiling point. The resulting beryUium sulfate [13510-49-1] solution is separated from unreacted soflds by countercurrent decantation thickener operations. The solution contains 0.4—0.7 g/L Be, 4.7 g/L Al, 3—5 g/L Mg, and 1.5 g/L Fe, plus minor impurities including uranium [7440-61-1/, rare earths, zirconium [7440-67-7] titanium [7440-32-6] and zinc [7440-66-6]. Water conservation practices are essential in semiarid Utah, so the wash water introduced in the countercurrent decantation separation of beryUium solutions from soflds is utilized in the wet milling operation. 

Soluble impurities can be extracted by washing with deionized or distilled water foUowed by filtration (1,12,26). Powders prepared by wet chemical synthesis are often washed and filtered for purification prior to use. The dewatering (qv) process can be enhanced by pressure filtration. Organic solvents can be used to remove water-insoluble impurities and wash-water sensitive materials. 

This is a favorable process because the side reaction products, nitrogen and water, are not pollutants and the sodium sulfate can be recovered and sold. Also, all of the wash water used to remove the sodium sulfate from the chrome oxide can be recycled. 

The KEN-FLOTE column (11) is one of several column flotation processes based on a countercurrent principle. The feed slurry containing reagents is iatroduced iato the column just below the froth zone. Air is iujected at the bottom of the column via an air sparger. Wash water is sprayed within the froth zone to reject the entrained impurities from the froth. Test results on this column iadicate that a 6% ash product coal having a combustible-recovery of 75—80% can be obtained. A 70—80% pyrite reduction is also claimed. Figure 2 shows the operation of such a column. 

Silver is most commonly recovered by electrolysis or metallic replacement from the processing solutions or by ion exchange (qv) from the wash water (123). Loss of chemicals from one tank into the next has been minimized. The color paper process has progressed from five chemical solutions, three washes, and a replenishment rate of 75 lL/cm (70 mL/ft ) of film for each of the five solutions to two chemical solutions, one wash, and replenishment rates of 15 lL/cm (16 mL/ft ) and 5 lL/cm (5 mL/ft ). For color negative films, developer replenishment has dropped from over 300 to 43 lL/cm (40 mL/ft ). Regeneration of the now reduced overflow has decreased chemical discharge by as much as 55% (124). 

An important aspect of economic consideration is the prevention of egg and egg product loss to the drain or the atmosphere, eg, a checked or cracked egg may be broken in the washer, and the contents go down the drain with the wash water. Other measurable losses during egg product production are Hsted in Table 5. 

The actual yield may be obtained from algebraic calculations or trial-and-error calculations when the heat effects in the process and any resultant evaporation are used to correc t the initial assumptions on calculated yield. When calculations are made by hand, it is generally preferable to use the trial-and-error system, since it permits easy adjustments for relatively small deviations found in practice, such as the addition of wash water, or instrument and purge water additions. The following calculations are typical of an evaporative ciy/staUizer precipitating a hydrated salt, if SI units are desired, kilograms = pounds X 0.454 K = (°F 459.7)/I.8. 

There are a number of commercially available surfactants that can be employed as an aid in filter cake moisture reduction. These reagents can be added to the filter feed sluriy or to the filter cake wash water, if washing is used. Since these reagents have a dispersing effect, flocculation may be required subsequently Typical moisture reduc-... 

---