Pumps condensate

Thermal power plant auxiliaries such as flow control of primary air fan, ID fan and forced-draught fans, boiler feed pumps circulating water pumps and condensate pumps, coal handling plant (e.g. ball mill, wagon tippler, and stacker reclaimer)... 

These applications have considerably more stringent performance requirements than any other application. Circulating water pumps, boiler feed pumps, forced-draught (FD) and induced-draught (ID) fans, pulverizers (ball mills) and condensate pumps are components in a thermal power station that may require extra safety in a standard motor to make it able to fulfil these requirements and withstand abnormal service conditions and system disturbances. Abnormal operating conditions may be one or more of the following ... 

Our example system has a flow-controlled feed, and the reboiler heat is controlled by cascade from a stripping section tray temperature. Steam is the heating medium, with the condensate pumped to condensate recovery. Bottom product is pumped to storage on column level control overhead pressure is controlled by varying level in the overhead condenser the balancing line assures sufficient receiver pressure at all times overhead product is pumped to storage on receiver level control and reflux is on flow control. 

Uncontrolled rod withdrawal 23. Loss of condensate pumps (one loop)... 

Trip of one feedwater pump (or condensate pump) 24. Feedwater low flow... 

Resin blockage caused trip of the condensate pump and main feedwater pumps,... 

Condenser tail pipes, used tvith any condenser, are sealed with a 34-foot leg into a sump, or with a condensate pump operating under vacuum on suction. With surface-type condensers, the level may be sealed in a receiver with a float or other type of level control. 

Discharge heads on chilled water pumps and condensate pumps, if manufacturer is to furnish. 

Condensate from the low-pressure coil together with that from the flash vessel will then drain to a collecting tank, or direct to a condensate pump, for return to the boiler plant. If the pressure of the flash steam is left to find its own level it will often be sub-atmospheric. As the condensate must then drain by gravity through the steam traps these also must be sufficiently below the condensate drain points to provide an appropriate hydraulic head, and a vacuum breaker fitted above the coil. The alternatives are to allow the condensate to drain directly to a condensate pump, or to supply additional low-pressure steam through a pressure-reducing valve, to maintain a positive pressure in the coil and flash vessel. 

Condensate pumps usually operate with an on/off action, so that the instantaneous flow rate during the on period is greater than the average rate of flow of condensate to the pump receiver. This increased instantaneous flow rate must be kept in mind when sizing the delivery lines. 

In chilled-water systems, pump shaft power adds to the heat of the circulating water. Similarly, if the chiller has a water-cooled condenser pump heat is added to that handled by the final cooler. Power is proportional to the flow and pressure ... 

The use of sacrificial anodes in circulating water systems is limited to the application of cathodic protection to stop gates, coarse screens and other plant that are readily accessible so that the anodes can be replaced when they are consumed. Such anodes are not normally used in condensers, pumps and auxiliary coolers for the following reasons ... 

Where the outlet drain is higher than the coil, the water needs to be pumped away for disposal. Condensate pumps are fitted to lift this water to drain bygravity. Such pumps are usually of the peristaltic type. 

The condensate return system is a post-boiler section system that includes all steam traps, condensate lines, associated manifolds and valves, condensate receiving tanks, save-all tanks, condensate pumps, and other auxiliaries for condensate recovery. 

The condensate return (returned, condensate or simply condensate) tank is positioned at the lowest point in a condensate return (CR) system and collects condensate from the various steam heating and process applications. If traps or condensate pumps are installed to aid the return of the condensate (as is usually the case), this is called a mechanical CR system. Nevertheless, some parts of the system may return condensate by gravity either to a condensate tank or directly to a FW tank. 

Condensate pumps generally deliver CR either to a deaerator or to a FW tank (ideally in an uncontaminated condition). The condensate pumps are controlled by a regulator similar to a FW regulator and may be adjusted by reference to the condensate level as seen through a condensate tank sight glass. 

Condensate system requirements are to check the condensate pumps, steam traps, and overall condensate return system. A loss of condensate return necessitates an increase in MU water to compensate for the shortfall in the FW system. 

Some sub-cooling of the condensate will usually be required to control the net positive suction head at the condensate pump (see Chapter 5, and Volume 1, Chapter 8), or to cool a product for storage. Where the amount of sub-cooling is large, it is more efficient to sub-cool in a separate exchanger. A small amount of sub-cooling can be obtained in a condenser by controlling the liquid level so that some part of the tube bundle is immersed in the condensate. 

Air conditioner condensate lines are sometimes installed so that they penetrate the slab to dispose of the water in the subslab area. Even when water is trapped, this can be a problem because the traps often dry up during the heating season. At this point they become radon entry routes. It is recommended that air conditioning condensate lines run to a drain that will not dry out or that a condensate pump is installed that collects the condensate and disposes of it through a water trap. Often a washing machine drain is located in a basement near enough to use it. 

Sensor Description Condensate Pump Discharge Condensate Polisher Effluent Economizer Inlet Hot Reheat Makeup... 

Surface area related pumping speed (area related impact rate according to equations 1.17 and 1.20, proportional to the mean velocity of the gas molecules in the direction of the cryopanel) a Probability of condensation (pumping)... 

Fig. 2.73 Areas of application for gas ballast pumps and condensers pumping water vapor (o. G. = without gas ballast)...

Condensate pumps are sometimes used to overcome such backpressure problems. However, these pumps are often not kept in good repair, and condensate is still lost to the sewer. Eliminating the steam inlet control valve of the type shown in Fig. 8.4 has helped recover condensate from many reboilers, supplied with low-pressure steam. 

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