Category Archives: Optimization

In air conditioning for the LM6000

I decided to clean my office over the weekend, and came across the Power Magazine from June 2013. One of the feature articles is on the ARCTIC inlet conditioning system by Energy Concepts, Kiewit Power Engineers and Nooter/Erikson.

ARCTIC stands for Absorption Refrigeration Cycle Turbine Inlet Conditioning. And that’s precisely what it does.

Designed around the LM6000 (but also available for other engines), the ARCTIC uses heat from the gas turbine exhaust to power an absorption chiller which cools a heat transfer medium for use in the gas turbine inlet. The system can use existing inlet coils, and can also run in heating mode. This is of special interest to the aeroderivative engines, due to their multiple control limits, which cause them to have an optimum compressor inlet temperature (CIT) for best output performance.

The optimum CIT for the LM6000 is between 46F and 49F (and varies between individual units to a small extent). The ARCTIC system can be setup to control the CIT to that optimum temperature, no matter the outside ambients. According to the Power Magazine article, the system can also start and stop automatically with the gas turbine.

With a drop of only 120F in exhaust temperature (for the LM6000, this is from ~840F to ~720F), there is still energy available for other uses from the exhaust gases, including hot water exports or combined cycle operation (which is more likely on frame based units).

Overall, a very intriguing design concept, and if you’re in the market for a new or upgraded inlet chilling system for your gas turbine, definitely worth looking into.

To read more about ARCTIC, view the Power Mag article here: http://www.powermag.com/improving-warm-weather-performance-of-the-lm6000/

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Improving GT Availability

This month’s Power Engineering magazine highlights one of the best papers of the 2010 Power Gen Conference.

See page 54 in Power Engineering, February 2011.

The whole paper can be found at PowerGenWorldwide in PDF form.

The paper gives details around MHI’s experience with increasing the availability of the M501F, but the information could be extrapolated to apply to all industrial gas turbines, and other equipment as well.

The highlights of the paper include planning for gas turbine performance from four difference angles of attack:

  1. Design
  2. Scheduled Maintenance
  3.  OEM Support
  4. Continuous Monitoring

Better designs, which include planning for maintenance, can lead to less downtime.  Especially when the designs lead to increased part longevity.  Time between repairs and/or replacements is on the rise as better coatings and materials are available.

Using experienced crews and well-tested procedures for your scheduled maintenance can lead to shorter outages overall, so your plant can get back on line – or at least available to be on line – faster.

OEM support, especially for newer designs, can improve troubleshooting efforts and may lead to upgrades in parts or services which further reduce down time in the future – especially if the upgrade means a part can operate longer between inspections.

Continuous monitoring – my personal favorite – can lead to finding problems when they’re small, and fixing small problems with a short outage – instead of waiting to find big problems later, requiring extensions on major outages if additional parts need to be ordered.

Monitoring technology is improving every year.  Neural net, or “smart” software can learn how a plant operates, then detect small abnormalities before alarm limits – or even warning limits – are reached.  Expertise is still needed to find the source of the abnormalities and solutions for getting back to ‘normal’ – but overall these new systems are effectively reducing downtime – leading to significant improvements in equipment availability.

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Absorption Inlet Chillers

Another great article from Power Engineering:
Innovation in Turbine Inlet Conditioning” from TIC and GE.
(October 2010, starting on page 51)

The article outlines an option to use absorption chillers instead of mechanical chillers for gas turbine inlet cooling. Using the GT exhaust gas energy as input to run the chillers – there is no (or very minimal) aux load requirement to run the chillers.

Sounds like a great idea to me!!

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