Heat exchange area

The relationship between heat exchanger area and overall heat transfer coefficient U is given by... 

In 1994 Stamicarbon introduced a pool condenser in the synthesis section (see Figs. 4 and 5). This allowed a 34% decrease in reactor volume and a 45% decrease in carbamate heat-exchange area, thus reducing costs considerably for equipment, stmctural steel, and constmction. 

The plate dryer may vary in size from 5-35 vertically stacked plates with a heat-exchange area between 3.8-175 m". The largest unit available has overall dimensions of 3 m (w) by 4 m (1) by 10 m (h). Depending upon the loose-bulk density of the material and the overall retention time, the plate dryer can process up to 5,000 kg/hr of wet product. 

The heatable areas of the diyer are the vessel wall and the screw. The diyer makes maximum use of the product-heated areas—the filling volume of the vessel (up to the knuckle of the dished head) is the usable product loading. The top cover of the vessel is easily heated by either a half-pipe coil or heat tracing, which ensures that no vapor condensation will occur in the process area. In addition to the conical vessel heated area, heating the screw effectively increases the heat exchange area by 15-30 percent. This is accomphshed via rotary joints at the base of the screw. The screw can be neated with the same... 

Several common salts have an inverse temperature solubility and readily precipitate to form deposits on hot boiler surfaces and other heat exchange areas. These include ... 

Repeating this procedure at the various temperature points selected, the heat-exchanger area may then be obtained as the area under a plot of Y.q vs. 1/6 A7 , or as A — Hq/UAT according to the following tabulation ... 

The batch system of heating is to be replaced by a continuous countercurrent heat exchanger in which the heating medium is a liquid entering at 388 K and leaving at 333 K. If the heat transfer coefficient is 250 W/m2 K, what heat exchange area is required Neglect heat losses. 

Table 3.3 Comparison of the calculated heat-transfer coefficients, heat-exchange areas and the estimated temperature gradients between the central reactor area and the outer wall of the reactor.

Heat exchanger, shell-and-tube heat exchange area, 0.6-2.9 m volume, 0.5-4 m 0.43... 

Heat exchange area Specific heat Mass in reactor Temperature... 

In the first pass, both the hot and cold fluids flow in cocurrent flow through the heat exchanger, whereas in the second pass, the cold fluid now flows countercurrent to the hot shellside fluid. Half the heat exchange area is therefore in cocurrent flow and half in countercurrent flow. 

Calculate the heat exchange area target for the network. 

Targets also can be set for total heat exchange area, number of units, and number of shells for 1-2 shell-and-tube heat exchangers. These can be combined to... 

Heat exchanger cost data can usually be manipulated such that fixed costs, represented by the Coefficient a in Equations H.2 to H.4, do not vary with exchanger specification2. Equations H.3 and H.4 can now be rearranged to give the modified heat exchanger area A as a function of actual area A and the cost law coefficients. 

A Absorption factor in absorption (-), or annual cash flow ( ), or constant in vapor pressure correlation (N-m 2, bar), or heat exchanger area (m2)... 

Ashell Heat exchanger area for an individual shell (m2)... 

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