Energy Optimization and Wireless Steam Traps

Emerson's Danny VandeputMany process manufacturing, oil & gas processing, and other industrial processes were designed in an era of inexpensive energy. This has not been the case for many years now. Emerson’s Danny Vandeput has written a South African Instrument and Control article, Control the cost of energy, to highlight how technology is helping to address these higher costs.

South-African-Instrument-and-Control-Control-the-cost-of-energyHe opens the article observing:

For some companies, energy costs now amount to over 25% of their total operating costs. At the same time, within industry there has been a greater emphasis on improving the environmental impact of production.

By optimizing energy consumption, emissions can be lowered and overall plant efficiency increased. Danny provides some areas to find energy savings:

…steam traps, compressed air stations and pressure relief valves (PRVs).

As steam flows from the boiler through the distribution network, some condensation occurs. Steam traps:

…are installed to remove condensation and enable the steam to flow freely.

Danny highlights the important role steam traps play:

  • Improve safety for plant personnel and equipment.
  • Increase plant throughput and product quality.
  • Reduce maintenance costs.
  • Reduce energy consumption, lowering fuel costs.
  • Meet environmental standards and goals.

Steam traps require maintenance to verify they are operating properly and not stuck in an open or closed position. For a stuck-closed position, it can:

…allow condensate to collect within the steam line. This build up can prevent steam from passing, with eventually slugs of condensate producing the ‘water hammer’ effect. This can cause damage to the pipework and fittings.

For the stuck-open case:

Apart from unusual heating patterns or noticeable sound, there are generally no external signs to indicate a defective steam trap which has failed in the open position…

Steam traps failed in an open position do not pose a direct threat to the process or safety of plant personnel, but there is a significant financial impact on the bottom line of the facility. When steam traps fail in the open position they allow steam to pass through continuously.

Generally accepted figures for steam trap failure rates are on the order of 15-20% per year. Manual inspections can catch these problems but are labor intensive and allow periods of energy wastes or water hammer conditions in between inspections.

Rosemount-708-Wireless-Steam-Trap-MonitorAs wireless technology has come to field devices, the opportunity for novel applications such as automated steam trap monitoring has become available. Danny explains [hyperlink added]:

Using Emerson’s Rosemount 708 Wireless Acoustic Transmitter, it is possible to monitor critical steam traps every minute of every day, to address failures as they happen and maximise energy savings. A combination of temperature measurement, with acoustic ‘listening’ provides visibility into steam trap states.

He concludes that this technology [hyperlinks added]:

…allows steam traps to be monitored throughout the plant, even in remote and hard-to-reach locations, with greater than 99% data reliability. The Rosemount 708 works with the plant’s existing WirelessHART network. If the plant does not have a wireless network, it is easy to start small with a Smart Wireless Gateway and any number of transmitters; with the resulting energy savings, the system will pay for itself within a matter of months.

To connect and interact with Danny and other wireless subject matter experts, join the Wireless track in the Emerson Exchange 365 community.

3 comments

  1. Jonas Berge says:

    What I love about WirelessHART is that you don’t have to build a dedicated wireless network just for steam trap monitoring and another dedicated network just for reflief valve monitoring and a third network for vibration monitoring etc. Since acoustic, valve position, and vibration transmitters are all available with WirelessHART they can also share the same single network and gateway, and all integrate the same way with the higher level systems. Add to this all the other measurements you can do on the same network like pressure, temperature, level, DP flow, pH, conductivity, and discrete points etc. It brings to mind Metcalfe’s law. A WirelessHART network once deployed in a plant soon becomes very valuable because you can do so much with it. Further reading:
    http://www.ceasiamag.com/article/wireless-for-asset-uptime/8689

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