Level and Flow Solutions for Pump Skids

Pump skids for fluid transfer are often found in field and factory processes. These skids move a broad range of fluids: from asphalt, cement slurries and drilling mud to potable water, hot condensate and every imaginable liquid chemical. Pump skids typically range from 10 HP electric-powered units to 1500 HP diesel skids with multiple pumps.

These pumps, especially condensate recovery pumps, can be configured as self-contained, modular skid systems. Modular skids are favored by many owner/operators, OEMs and plant engineers because of their flexibility, cost-effectiveness and reduced site disruption during fabrication. This post will discuss level and flow solutions for pump skids in the power industry used for condensate recovery and is part of an occasional Magnetrol® blog series on modular skid systems.

Condensate Recovery Pump Skid

Because condensate leaving a steam trap retains up to 25% of its original heat energy, recovery and utilization of condensate reduces feedwater make-up, fuel and water treatment costs. Pumping is necessary when the condensate return pressure is higher than the process/source condensate pressure.

A condensate recovery pump skid typically has one to four pumps, a condensate receiver tank (15 to 1,500 gallons; 57 to 5,678 liters), control panel, gate valves, drain valves, blowdown valves, condensate piping, and may include a heat exchanger, flash vessel or condensate cooler.

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Level and Flow Applications for Condensate Recovery Pump Skids 

  1. Heat Exchanger or Steam Heater
    In steam heaters, steam is condensed while the process fluid is heated. One common control arrangement cascades the temperature controller to a level controller. The controller senses the rise in level due to an increase in process load and opens a fluid valve.
    Continuous Level: Eclipse® Model 706 Guided Wave Radar Transmitter or E3 Modulevel® Displacer Transmitter
    Point Level: Model B35 External Cage Float Switch
  1. Condensate Receiver Tank
    A receiver tank is placed below the heat exchanger to receive condensate that drains from the bottom. When the control senses the high level in the tank, it will actuate a valve to remove the accumulated condensate.
    Continuous Level: ECLIPSE Model 706 Guided Wave Radar Transmitter; E3 MODULEVEL Displacer Transmitter; Pulsar® Model RX5 Radar Transmitter; Model R82 Radar Transmitter or Echotel® Model 355 Non-Contact Ultrasonic Transmitter
    Point Level: Model B35 External Cage Float Switch
  1. Flash Vessel and Condensate Cooler
    Condensate and flash steam enter the flash vessel. The condensate falls to the base of the vessel where it is drained. Level measurement is necessary to control the flash tank level. In this stage of the process, the challenges are elevated temperatures and pressures.
    Continuous Level: ECLIPSE Model 706 Guided Wave Radar Transmitter
    Point Level: Model B35 External Cage Float Switch
  1. Pump Protection
    Pumps operating in a reduced or no-flow condition can overheat and rupture the pump’s seal. A flow switch along a pump’s discharge piping will actuate an alarm and shut down the pump when liquid flow drops below the minimum flow rate.
    Flow Alarm: Thermatel® Model TD1/TD2 Thermal Dispersion Switch for low-flow cutoff

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