Heat exchanger cooling coil

The fluid properties for the three processes may be considerably different. The CCC process uses a low pH solution (containing water and the acid product) whereas both DCL and FTS use hydrocarbon like liquids. Physical properties such as surface tension, viscosity, specific heat and thermal conductivity for these two cases may be quite different. Since the FTS is a very energetic process, the reactor may also contain some internals such as heat exchangers (cooling coils) etc. Some physical and thermal properties for these systems are outlined in Table 2. 

Air heating and cooling coil As tube or plate heat exchanger in which air, the secondary fluid, is either heated or cooled with a primary medium. 

For reactions with a sizable heat effect, heat is abstracted in several ways reflux condenser, internal coil, external heat exchanger, cooling jacket, and half-round pipes wound on the reactor body. The overall heat transfer coefficient with water in the tank for a water-cooled or steam-heated jacketed vessel is 0.15-1.7, for a tank with water-cooled half-round pipe is 0.3-0.9, and for a tank with water-cooled internal coil is 0.5-1.2kW/m K (Rose, 1981). 

S. cerevisiae is produced by fed-batch processes in which molasses supplemented with sources of nitrogen and phosphoms, such as ammonia, ammonium sulfate, ammonium phosphate, and phosphoric acid, are fed incrementally to meet nutritional requirements of the yeast during growth. Large (150 to 300 m ) total volume aerated fermentors provided with internal coils for cooling water are employed in these processes (5). Substrates and nutrients ate sterilized in a heat exchanger and then fed to a cleaned—sanitized fermentor to minimize contamination problems. 

Process. A typical indirect hydration process is presented in Eigure 1. In the process, propylene reacts with sulfuric acid (>60 wt%) in agitated reactors or absorbers at moderate (0.7—2.8 MPa (100—400 psig)) pressure. The isopropyl sulfate esters form and are maintained in the Hquid state at 20—80°C. Low propylene concentrations, ie, 50 wt %, can be tolerated, but concentrations of 65 wt % or higher are preferred to achieve high alcohol yields. Because the reaction is exothermic, internal cooling coils or external heat exchangers are used to control the temperature. 

When the solute has a large heat of solution or when the feed gas contains high percentages of the solute, one should consider the use of internal coohng coils or intermediate external heat exchangers in a plate-type tower to remove the heat of absorption. In a packed tower, one could consider the use of multiple packed sections with intermediate hquid-withdrawal points so that me hquid coiild be cooled by external heat exchange. 

Another type of crossflow cooling tower is the wet-dry tower, which consists of a normal crossflow tower over which a few air coils are placed. The hot water is first cooled by an air cooled heat exchanger and then drops to the wet cooling tower where more cooling is obtained by the evaporative mechanism. Figures 5 and 6 provide examples. In contrast, deck-filled towers contain tiers of splash bars or decks to aid in the breakup of water drops to increase the total water surface and, subsequently, the evaporation rate. 

Battery, heat exchange coil A device used to either heat or cool air in a duct run. 

Cooling coil A heat exchanger (battery) in which the chilling of a fluid occurs by means of a heat-transfer medium. 

The resistance of titanium in nitric acid is good at most concentrations and at temperatures up to boiling . Thus tubular heat exchangers are used in ammonium nitrate production for preheating the acid prior to its introduction into the reactor via titanium sparge pipes. In explosives manufacture, concentrated nitric acid is cooled in titanium coils and titanium tanks are... 

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