Cooling requirement crystallization

Ideal Performance and Cooling Requirements. Eree carriers can be excited by the thermal motion of the crystal lattice (phonons) as well as by photon absorption. These thermally excited carriers determine the magnitude of the dark current,/ and constitute a source of noise that defines the limit of the minimum radiation flux that can be detected. The dark carrier concentration is temperature dependent and decreases exponentially with reciprocal temperature at a rate that is determined by the magnitude of or E for intrinsic or extrinsic material, respectively. Therefore, usually it is necessary to operate infrared photon detectors at reduced temperatures to achieve high sensitivity. The smaller the value of E or E, the lower the temperature must be. 

Water use in copper sulfate plants is mainly used as contact water, noncontact cooling water, washdowns, and as wash water, where solid copper sulfate product is required. Noncontact water is generated as steam condensate from the evaporators and is used to cool the crystallizers. Contact wastewater comes mainly from washdowns, spills, and leaks. Both types of wastewater contain relatively small quantities of copper sulfides and other heavy metals. 

This hydrochloride may contain traces of potassium chloride, which can be removed by dissolving the hydrochloride in hot absolute alcohol (50 g. requires 1 1.) and filtering from insoluble material. An equal volume of dry ether is then added to the warm alcoholic solution, and, after cooling, the crystallized product is filtered. The recovery is 40-43 g., m.p. 210-212° (230°) (Notes 3 and 4). 

A mixture of 5-amino-Y-phenyl-l//-pyrazole-4-carboxamide 1 (0.2 g, 1 mmol) and arylidenepyruvic acid 2 (0.2 g, 1 mmol) was refluxed in 5 ml of acetic acid for 10-20 min until a solid started to precipitate (Scheme A.26). After cooling, the crystals formed were removed by filtration, washed with ethanol and dried in air. If required, the products were crystallized from ethanol. Yield 68%. Melting point 254-256°C. 

Should the reactor effluent, which contains the product and unconsumed reactants, be sold as is. or should the product be separated from the reactants and the latter be sent back to the reactor If separation is desirable, how can it be accomplished Heat the mixture and draw off and condense the vapor, which will be richer in the more volatile substances than the original mixture Add another substance that extracts the product and is immiscible with the reactants, and then separate the two phases mechanically If all of the process materials are gases at the reaction temperature, can the mixture be cooled to a temperature at which the product condenses but the reactants do not. or vice versa, or if they are liquids can the mixture be cooled to a temperature at which the product crystallizes If one of these alternatives is chosen, what kind of equipment is needed What size What materials What are the heating or cooling requirements Are controls needed to keep the operation of the process within rigid limits What kind of controls Should they be manual or automatic ... 

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