Contact cooling

The solution involves the use of two water substreams for scrubbing at 293 and 298 K. The first coolant is employed to undertake the cooling duty. Several conceptual flowsheets can be developed to implement this solution. Figures 9.18a and b illustrate such configurations. The developed mass exchanger is composed two sections. The top section employs Si,3 to reduce the ammonia composition in the gas from 0.13% to 0.10% and operates at an average water temperature of 293 K. In Fig. 9.18a, temperature is reduced by indirect contact cooling of the... 

Internal liquid injection into the diffuser passage is used in a few applications for direct contact cooling. The quantity and quality of the liquid must be carefully controlled. 

For a compression operation handling some condensable vapors, the temperature rise will be approximately 13°F. These values are considerably lower than for conventional polytropic compression. They are almost isothermal and demonstrate the contact cooling that takes place during compression. 

Wastewater is generated in the primary zinc and primary cadmium recovery subcategories by acid plant blowdown, which results from sulfuric acid recovery, air pollution control, leaching, anode/ cathode washing, and contact cooling. The streams may contain significant concentrations of lead, arsenic, cadmium, and zinc. Tables 3.26 and 3.27 present classical and toxic pollutant data for the primary zinc and primary cadmium subcategories. 

Homogenizing, annealing, and aging are dry processes whereas solution heat treatment typically involves significant quantities of contact cooling water. 

Contact cooling water is any wastewater that contacts the aluminum workpiece or the raw materials used in forming aluminum. 

Direct chill casting is the pouring of molten aluminum into a water-cooled mold. Contact cooling water is sprayed onto the aluminum as it is dropped into the mold, and the aluminum ingot falls into a water bath at the end of the casting process. 

Generally, water is used in this plant to cool, leach, filter wash, scrub, heat, and washdown. The unreacted ore is slurred and sent, along with chromium and other impurities originally present in the ore, to the treatment plant. The boiler blowdown, which is sometimes contaminated with chromium escaping from the process area, adds to the volume of wastewater coming from the plant. The non-contact cooling water from the plant contains dissolved sulfate, chloride, and chromate thus it is sent to a wastewater treatment plant. The scrubber water may be used to slurry the ore or discharged. 

Mullin, J. W. and Williams, J. R. Chem. Eng. Res. Des. 62 (1984) 296-302. A comparison between indirect contact cooling methods for the crystallisation of potassium sulphate. 

Cooling water constitutes a major portion of the total in-plant wastes in fertilizer manufacturing and it includes water coming into direct contact with the gases processed (largest percentage) and water that has no such contact. The latter stream can be readily used in a closed-cycle system, but sometimes the direct contact cooling water is also recycled (after treatment to... 

Mori, T. Mori, Y.H. (1989a). Characterization of gas hydrate formation in direct-contact cool storage process. Int. J. Refrigeration, 12 (5), 259-265. 

A direct-contact gas cooler system operates as follows Approximately 35,000 lb/hr of bone-dry air is passed over hot trays. The air is heated from 150°F to 325°F as it passes over the trays. It exits from the unit with a due point of 105°F. The hot air is sent to a direct-contact cooler, where its temperature is reduced back to 150°F. During the cooling stage, the air is dehumidified with water that is heated frpm 75°F to 105°F. The unit is rated at 3.5 inches of water pressure drop (a) Determine the number of diffusion units needed for this operation and (b) Establish the required dimensions for the direct-contact cooling tower (Hint Use standard low-pressure-drop data from the literature. Some of the older literature give pressure drop data for simple fill. See Sherwood, T. K. and C. E. Reed [6]. 

Influence of Atmospheric Precipitation on the Operation of a Natural Draught Indirect-Contact Cooling Tower... 

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