Condensate circulation

The centrifugal pump is the type most widely used in the chemical industiy for transferring liquids of aU types—raw materials, materials in manufacture, and finished produc ts—as well as for general services of water supply, boiler feed, condenser circulation, condensate return, etc. These pumps are available through avast range of sizes, in capacities from 0.5 mVh to 2 X 10 mVh (2 gal/min to 10 gaJ/min), and for discharge heads (pressures) from a few meters to approximately 48 MPa (7000 Ibf/iu"). The size and type best suited to a particular apphcation can be determined only by an engineering study of the problem. 

A common form of turbine pump is the vertical pump, which has the pump element mounted at the bottom of a column that serves as the discharge pipe (see Fig. 10-46). Such units are immersed in the liquid to be pumped and are commonly used for wells, condenser circulating water, large-volume drainage, etc. Another form of the pump has a shell surrounding the pumping element which is connected to the intake pipe. In this form, the pump is used on condensate service in power plants and for process work in oil refineries. 

Capital Cost Costs of basic system, condenser, circulating water piping, makeup pumps and blowdown facilities, and intake and discharge systems. Cooling Capacity System sizing, air-to-water surface contact, dry- and wet-bulb temperatures for relative humidity, wind speed and direction, range and approach. 

Turbine pumps mix features of a simple propeller (axial flow) pump with a centrifugal pump and are often referred to as units with mixed flow. A simple turbine pump carries curved vanes on a central rotating spindle. Such pumps are often immersed in the liquid and find use in closed-loop circulation systems, in condenser circulating water, and in sumps and wells. Turbine pumps have noteworthy pumping capacity, and like positive displacements pumps are often used for heads up to about 100 ft/stage with capacities of up to several hundred gallons/minute. 

The vacuum applied to all stages should be the highest level to be used in operation. Condensers, circulating pumps, and condensate removal systems can be used to handle the water evaporated during the test. Under no circumstances should the absolute pressure go below 0.6 kPa, where evaporative cooling of the water will take the temperature to the freezing point. 

Condenser Circulating Water Three pressure monitors on each of two headers 2/3 on either header Low pressure on either header... 

Figure 2.17 Condensation plant with condensate circulation. Superheat is dissipated to prevent buildup of solid incrustations at the inlet part of the heat exchanger tubes.

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