Washing of gases

It may become necessary to work up solid products with the same solvent as used for crystallization. Cakes should not be allowed to dry out before washing, as air or inert gases result in evaporation of the solvent, and this may re.sult in the deposition of impurities, present in the dis.solved state, on the crystals. Such impurities when deposited are difficult to wash. In. some ca.ses washing of wet cake is done by replacing the solvent with another one, typically having a lower boiling point, so that in the final material loss of drying is within limits and the new solvent is more acceptable than the earlier one. 

Absorption. In theory, the penetration of one substance into another. In refining and petrochemicals processing, separation of gases by a scrubbing or washing operation with a liquid. Preferential solubility is shown for one or more of the components in the gas mixture allowing a separation... 

The apparatus is arranged in a hood, as shown in illustration. The narrow reaction bottle (A), of about 500-cc. capacity and having a wide mouth, is provided with an efficient mercury-sealed mechanical stirrer, an inlet tube (BJ for admitting the mixture of gases, and an outlet tube connected with the wash bottle (E). Into (A), contained in a water bath at 20°, is placed 200 g. (2.17 moles) of dry toluene, and then 30 g. (0.15 mole CU2CI2) of cuprous chloride (Note 1) and 267 g. (2 moles AICI3) of finely powdered anhydrous aluminum chloride are added rapidly with active stirring. 

Wet deposition involves the adsorption of gases and aerosols on surfaces after removal by rain, snowfall, etc. Water solubility and vapour pressure are determinant for this process. Compounds with low H constants are washed out from the atmosphere faster than those with high H. The efficiency in which rain (Crain) or... 

The acid gases, usually CO2 and H2S, are removed by scrubbing with diethanolamine or monoethanolamine solutions and possibly an additional caustic treatment. Older processes used caustic solutions of 5-15 wt% NaOH followed by a water wash. Of course, the spent caustic creates a disposal problem it must be neutralized with acid and then properly disposed of according to prevailing pollution and hazard waste standards. Different column configurations have been proposed, but usually large scrubber towers with well over 30 valve-type trays are used. 

Washing of blast furnace flue gases CATEGORY GREEN... 

A number of materials,10 water, certain organic acids, the most important of which is citric acid, and certain inorganic salts, interfere with the determination. The decarboxylation cannot be conducted in the presence of nitrates and when carbonates are present two separate determinations of carbon dioxide are necessary. The procedure is also inapplicable when oxidizing compounds which are soluble in the hot reagent are present. Another interfering substance, sulfur dioxide,01 can be eliminated by the use of a saturated, acidified (sulfuric acid) solution of potassium dichromate to wash the gases evolved by the decarboxylation procedure. 

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