The benefits of any condensate recovery system are well documented in industries relying on steam generation for their processes. Condensate has real value in that every gallon recovered spares the cost of additional makeup water, makeup water treatment and/or wasteful discharge to municipal or other systems. Oftentimes, it is the instrumentation, or lack thereof, that limits the performance of the overall system causing the condensate recovery process to fall short of financial expectations. Three areas of particular interest relative to efficiency when it comes to level controls are the condensate receiver and main condensate tanks, condensate pumps and associated valves as well as any shell and tube heat exchangers/condensers.
The Condensate Recovery Process
The condensate receiver tanks accept blow‐through steam and condensate from various steam process groups throughout a plant. Condensate is later pumped to the main condensate tank where it is stored pending reintroduction into the steam generation cycle. The shell and tube heat exchanger/condenser allows what would otherwise be waste energy to be recovered in the form of flash steam from the receiver tank to preheat makeup water or other process fluids through the heat of condensation. The resulting condensate drains back to the condensate or condensate receiver tank.
The level transmitter on the condensate receiver tank facilitates the automatic management of the condensate level to ensure adequate capacity is available to accommodate (recover) condensate from various plant processes as well as maintaining sufficient headspace in the vessel for the creation of flash steam. Aside from being a critical asset for the plant, the condensate in the condensate receiver tank also protects valves and condensate pump seals from direct exposure to high temperature steam while maintaining a minimum head pressure on the pump. This prevents hardware damage, expensive maintenance and downtime of the receiver tank, and subsequent ripple effects on the steam generation cycle and makeup water requirements. Lastly, the level transmitter provides the control signals for the valves and condensate pump necessary to transfer condensate from the receiver to the main condensate tank, ensuring approximately 15 percent level retention for the aforementioned reasons. At this point, the main condensate tank level transmitters take over to manage boiler feed water supply to service steam generation demand.
Advantages of Guided Wave Radar and Magnetic Level Indicators
In order to ensure that the condensate recovery process has efficient level control, plants need to install high-quality level instrumentation. Guided wave radar (GWR) and magnetic level indicators are two technologies that can help eliminate hidden maintenance costs. GWR and magnetic level indicators are designed for high-temperature steam applications. Both technologies provide reliable measurement in a wide range of applications. They require no calibration and have setup wizards with full diagnostics for fast setup and fault isolation. Each instrument can be pre-configured for the specific application where it is being placed. The instrumentation hardware is simplified—and in the case of GWR, has no moving parts, eliminating instrument-induced errors. Using a GWR transmitter in conjunction with a magnetic level indicator provides level measurement for every aspect of the condensate recovery process.
With proper level instrumentation, the hidden maintenance costs in this process can be reduced or even eliminated. Learn more about GWR, magnetic level indicators and other technology for monitoring the steam generation cycle and condensate recovery process at steamgen.magnetrol.com.