Liquid wastes refrigerant

The DirCon freeze crystallization process is a technology that can be used to purify aqueous waste streams and concentrate liquid waste by the freezing and subsequent melting of the liquid. This technology is a type of direct-contact secondary-refrigerant freeze crystallization and operates on the principle that when water freezes, the crystal structure that forms naturally exudes contaminants from its matrix. The terms freeze crystallization and freeze concentration are often used interchangeably. 

The liquefied gas must be maintained at or below its boiling point. Refrigeration can be used, but the usual practice is to cool by evaporation. The quantity of liquid evaporated is minimized by insulation. The vapor may be vented to the atmosphere (wasteful), it may be compressed and reliquefied, or it may be used. 

This is the vessel where the refrigerant rejects its heat to waste or reclaim, turning back to liquid in the process. Sub-cooling is practiced by the removal of further heat. This prevents liquid flashing back to vapor on return to the evaporator. 

Removal of liquids from the cup is accomplished by the same device as in the Sequenator . The effluent line extends from the groove in the group through the delivery head to a valve which may be connected either to the fraction collector or to the waste bottle. The fraction collector is housed in a compartment which may be refrigerated and evacuated. This provision permits immediate drying under nitrogen of the fractions collected. 

Liquid sulphur dioxide finds occasional use as a refrigerating liquid for the manufacture of ice and as a solvent for the extraction of fats and oils from bones and other waste animal matter. It is also employed in the refining of natural petroleum, owing to its property of dissolving aromatic and other heavy hydrocarbons which are present in petroleum distillates.1 When the distillate is shaken with liquid sulphur dioxide at a low temperature, separation into two layers occurs, one of which is the sulphur dioxide solution, the other the purified distillate containing paraffin hydrocarbons and naphthenes, which remain unaffected. 

The stability and the redox balance of As(III) and As(V), which account for almost all of the As content of water, are basically affected by temperature, concentration of each species, pH, and the type of liquid matrix. As a rule, calibrants for these two As species dissolved in deionized water at a concentration higher than 20 pg ml-1 as well as filtered ground, potable, and waste water samples can be stored for several weeks without significant alteration in their redox state if kept in a refrigerator, that is, protected from sunlight and at a temperature of 0-4°C (no freezing) [100, 101]. The use of preservatives should be avoided as no conclusive evidence has been provided of their positive effect on the stability of As species moreover, antioxidants like ascorbic acid may cause either the... 

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