Steam jet type utilities requirements

Example. To produce 20 tons of refrigeration while delivering 50°F chilled water, the steam consumption depends upon the quantity and temperature of the cooling 

Ludwig, E. E., Applied Process Design for Chemical and Petrochemical Plants, Vol. 3, 2nd Ed., Gulf Publishing Co., pp. 208, 209. 

Steam and cooling water requirements for ammonia absorption refrigeration systems are shown in Table 1 for single-stage and two-stage units. The tables are based upon cooling water to the condenser of 85°F with 100°F condensing temperature. Water from the condenser is used in the absorbers. 

Example. For an evaporator temperature of -lO F, a steam rate (300°F saturated temperature in the generators) of 33.61b/hr/ton refrigeration is required. Also, 5.4gpm cooling water/ton refrigeration, assuming a 7.5°F rise through the condenser, are required in this system. 

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Refrigerant temperatures greater than 32°F suggest the steam jet or lithium bromide absorption system. Between 30°F and —40°F, the ammonia-water absorption or a mechanical compression system is indicated. At less than —40°F, a mechanical compression is used, except in special desiccant situations. The economics of temperature level selection will depend on utility (steam, power) costs at the point of installation and the type of pay-out required, because in some tonnage ranges, the various systems are competitive based on first costs. 

The utilities required for steam jet refrigeration operation often determine the selection of these units, between manufacturers and between types of refrigeration. As the chilled water temperature off of the unit approaches 32°F, the cost of the basic unit and its steam and cooling water requirements rise rapidly. 

Full-boiled saponification or the kettle process utilizes all the concepts of saponification, washing and fitting required to produce high-quality soaps. There have been some developments particularly at the saponification stage of this process. For example the Unilever method uses a type of cross-jet to emulsify the reactants and deliver them to a pan rather than simply boil the reactants together (Owen, 1951). This procedure allows savings to be made in steam consumption. 

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