Refrigerants common

Liquefied Petroleum Gas (LPG) - Hydrocarbon fractions lighter than gasoline, such as ethane, propane, and butane, kept in a liquid state through compression and/or refrigeration, commonly referred to as "bottled... 

Waste heat must occasionally be removed from a process at below-ambient temperatures. This is normally accomplished by evaporating a light fluid called a refrigerant. Common industrial refrigerants are... 

Before the late 1920s (when Freon was invented), household refrigerators commonly ran on ammonia (NH3) or sulfur dioxide (SO2) gases. If you aren t already familiar with them, do a quick search on the safety hazards of these compounds. Would you rather have one of these old appliances in your kitchen, or a CFC-based fridge Does your choice introduce conflict between what s best for... 

Many alkylation units use auto refrigeration to cool their reactors. Effluent refrigeration commonly used on Stratco units also falls within this classification. To maximize isobutane purity in the refrigerant recycle stream, circulating refrigerant is depropanized. 

A refrigeration system is a heat pump in which heat is absorbed below ambient temperature. Thus the appropriate placement principle for heat pumps applies in exactly the same way as for refrigeration cycles. The appropriate placement for refrigeration cycles is that they also should be across the pinch. As with heat pumps, refrigeration cycles also can be appropriately placed across utility pinches. It is common for refrigeration cycles to be placed across a utility pinch caused by maximizing cooling water duty. 

Many seed oils, especially sunflower and linseed, contain waxes which serve as a protective coating for the seed. These waxes soHdify at colder temperatures and impart turbidity to the oil and interfere with subsequent processing. They are commonly removed from the cmde oil by refrigeration followed by filtration, a process commonly known as winterization. 

Aqueous solutions of propylene glycol display excellent antifree2e properties and are therefore valuable as low temperature heat-transfer fluids. For apphcations involving indirect food contact, heat-transfer fluids formulated with the USP grade product are preferred, since there could be inadvertent contact with a food product. These fluids are commonly used in the brewing and dairy industries as well as in refrigerated display cases in retail grocery stores. 

Secondary coolants frequently are called brines because such fluids originally were mixtures of salts and water. Common refrigeration brines are water solutions of calcium chloride or sodium chloride. These brines must be inhibited against corrosion. 

Gaseous helium is commonly used as the working fluid ia closed-cycle cryogenic refrigerators because of chemical iaertness, nearly ideal behavior at all but the lowest temperatures, high heat capacity per unit mass, low viscosity, and high thermal conductivity. 

Large quantities of butane are shipped under contract standards rather than under national or worldwide specifications. Most of the petrochemical feedstock materials are sold at purity specifications of 95—99.5 mol %. Butane and butane—petroleum mixtures intended for fuel use are sold worldwide under specifications defined by the Gas Processors Association, and the specifications and test methods have been pubHshed (28). Butanes may be readily detected by gas chromatography. Butanes commonly are stored in caverns (29) or refrigerated tanks. 

Heat Pumps. Because of added capital and complexity, heat pumps are rarely economical, although they were formerly commonly used in ethylene/ethane and propylene/propane spHtters. Generally, the former spHtters are integrated into the refrigeration system the latter are driven by low level waste heat, cascading to cooling water. 

Heat Pumps. A heat pump is a refrigeration system that raises heat to a useful level. The most common appHcation is the vapor recompression system for evaporation (qv) (Fig. 14). Its appHcation hinges primarily on low cost power relative to the alternative heating media. If electricity price per unit energy is less than 1.5 times the cost of the heating medium, it merits a close look. This tends to occur when electricity is generated from a cheaper fuel (coal) or when hydroelectric power is available. 

The newer HFC refrigerants are not soluble in or miscible with mineral oils or alkylbenzenes. The leading candidates for use with HFC refrigerants are polyol ester lubricants. These lubricants are derived from a reaction between an alcohol and a normal or branched carboxyflc acid. The most common alcohols used are pentaerythritol, trimethylolpropane, neopentjlglycol, and glycerol. The acids are usually selected to give the correct viscosity and fluidity at low temperatures. 

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