Hunting for Green Steam

SDT200SteamTrap_DSC02524

Sustainability and Ultrasound Testing

The Paradox of Sustainability…

When manufacturers face uncertain economic headwinds, the word “Sustainability” can be a paradox.

In a good economy it’s fashionable to invest in green initiatives that promote  environmental sustainability. Reduce that carbon footprint. Conserve energy. Reduce waste. Sustainability under these circumstances paints a picture of responsible big business putting emphasis on the needs of community and planet first.

The paradox occurs when economic conditions turn south. Factories struggle to carve profits from their assets. Green initiatives no longer survive the budget cuts. In fact they are often the first programs to go.

Sustainability is redefined as “doing whatever it takes to keep the doors open.”

 

…Is Not Really a Paradox At All

But going green should never go out of vogue. Not when the benefits so profoundly affect bottom line. Especially if your end product is commoditized and price sensitive.

The key point is this. Green initiatives have a greater positive impact on company profits than they do on the environment. Don’t abandon them because they appear, on the surface, to be an unnecessary cost.

Sustainable projects need not be a paradox at all! Because they are not just about the environment, and not just about producing your product as efficiently as possible. They are about doing both at the same time.

Ultrasound: A Green Technology

Ultrasound technology lends its hand well for many energy efficient applications. Compressed air management programs reduce the energy spent on this tearfully expensive utility. Properly lubricated bearings consume less energy than those that are over or under greased. And steam systems, often overlooked, offer opportunities too.

Condition Monitoring in Steam Systems

Steam is an important process in power generation, pulp and paper, and food processing. Maintain a healthy steam system and you reap benefits for green initiatives, cost management, product quality, and asset reliability.

Efficient steam systems retain their heat better than wasteful ones. Less fossil fuels are burned; a positive impact on carbon footprint and production throughput.

The steam is kept pure which means less corrosion and greater asset lifecycle. We’re talking about boilers, condensers, and steam traps making it deeper into the PF curve. That’s a positive for CAPEX. Less reactive maintenance intervention is required to keep things running. That’s a positive for OPEX.

“But wait!” you say. “Isn’t condition monitoring something we do on rotating assets?”

Of course. Ultrasound inspection of steam systems does not just apply to stationary assets like traps and condenser tube leaks. So let’s add boiler feed pumps and electric motors to your project list. And, while we are at it, include ultrasound scans of the MCC panels.

Ultrasound is Versatile

If you are new to ultrasound, you may be wondering how this one technology can do so much.

Ultrasound detectors hear high frequency sound and convert it to audible sound while maintaining the original characteristics and qualities. For example,

  • The ultrasound of a compressed air or steam leak sounds like a leak (hissssssss).
  • The ultrasound of a dry bearing suggests to you that it needs grease.
  • The ultrasound produced by poor gear mesh or broken gear teeth has grinding and clicking characteristics.
  • The ultrasound of an electrical arc in a panel reminds you to put your protective gear on before opening the panel (PLEASE!!!!).

An ultrasound detector lets you listen to, measure, trend, and record important data about the health of your plant’s assets; all the while remaining ambivalent to surrounding plant noise. That’s right, all these inspections are carried out while the plant is in full operation. Just mind your safety!

Ultrasound Measures how FIT Your Assets Are

Ultrasound is great for listening to Friction, Impacting, and Turbulence (FIT) in both airborne and structure borne situations. FIT present energy peaks in ultrasound frequencies where problems appear early in the PF curve. Your reward is a bigger window of opportunity to take action. What action?

  • Schedule additional data collecting with complementary technologies to confirm your diagnosis.
  • Order parts and schedule labour for the shutdown (No More Overtime!!)
  • Stop glorifying firefighting and start celebrating UPTIME.

Preservation of your operational and capital budgets while creating a work culture that supports environmental sustainability. Now that is something everyone can get behind.

FIT Steam Traps are an Opportunity for Green Wins.

Traps are necessary to maintain the healthy operation of the entire steam system. They purge air, condensed steam and CO2, and other impurities from the system. The number of traps used, the size of the traps used, the type of traps used, and their placement in the system are all carefully detailed by engineering.

When traps fail the original design is compromised and the entire system becomes an energy wasting, environment polluting pig.

Problem is failed steam traps don’t always exhibit symptoms that are obvious. Traps failed shut may create some back pressure. Traps failed open may detract from the quality and purity of steam. Some traps can be found just flapping back and forth allowing condensate to flow back into your pure steam.

Your steam system keeps running; just not very efficiently.

All failure modes for steam traps produce either Turbulence, Friction, Impacting, or all three.

How many failed steam traps is too many; and at what cost to plant and planet?

The standard for testing steam traps is to compare upstream and downstream ultrasound and temperature measurements. Advanced ultrasound systems hear more. They most advanced ones record scalable, and comparable dynamic time signals. Now instead of just listening, ultrasound inspectors can visualize the condition of steam traps.

See the two time signals.

Steam Trap Purging
Figure 1 – Steam Trap Purging
Steam Trap Failed Open
Figure 2 – Steam Trap Failed Open

Even to the untrained eye it is quite obvious which trap is purging and which one is failed. Ultrasound leaves no guesswork as to which traps are draining resources.

How About Heat Exchangers?

Heat exchangers are used to efficiently transfer heat energy from one fluid to another without allowing the fluids to come in contact with each other. They contribute to sustainability by recovering wasted heat or cooling energy. Recovery re-purposes energy to processes or even building heating.

In power generation surface condensers maintain turbine efficiency while promoting long life cycle for boiler room components. Spent steam from the turbine is condensed back to its liquid state, then collected in a hot well before being pumped back to the steam generator to repeat its cycle. The cooling water is kept separated from the purified condensed steam and the cooling process creates a significant vacuum which helps maintain turbine efficiency.

This simplified explanation reveals two important inspections for the ultrasound inspector.

  1. Finding system vacuum leaks
  2. Finding tube leaks inside the condenser shell

Vacuum is a by-product of the cooling process and adds to turbine efficiency. System leaks negate that advantage. Ultrasound easily finds the vacuum leaks so they can be addressed and eliminated.

Tightness of the tube and shell of heat exchangers is both complex and vexing. There are several procedural choices for ultrasound inspectors.

External tightness testing is used to inspect all joints, fittings, valves, valve stems, inlets, and connectors. Check the steam jet vacuum pump ejectors as well using the same flexible wand prescribed for high pressure steam leaks. Inspection of the shell for tightness will verify end plate seals and inlet/outlet piping.

Inspecting the tube bundle will depend on whether the system is online or offline. For online inspections only the contact mode is useful and only the periphery tubes can adequately be checked. Offline inspection means removal of the end plates is possible. Larger condensers are equipped with access doors. This exposes the tube ends to the ultrasound inspector.

Pressurize the shell by connecting low pressure air through the inlet/outlet piping. Plug all other inlets. Then using a flexible wand listen for turbulent flow in each tube. Identifying cracked, leaking tubes and either plugging them or replacing them (dependent on downtime allotment) will improve overall green efficiency and maintain the purity of the water circulating through the boiler room.

Summary

Creating a culture of sustainability for your company shouldn’t be a compromise. Green initiatives add value for the environment and the bottom line. These projects should prevail in both good and bad economic times. The key is to brag and celebrate your success to the stakeholders that fund things. Report return on investment and your project will be sponsored for the long haul.

Finding green opportunities with ultrasound in the steam plant is a great place to start. The applications are simple to implement, do not require extensive training, and ROI reporting can be done by easily extractable data.

To Hear More about companies that have successfully improved steam systems with ultrasound please contact SDT Ultrasound Solutions.

by Allan Rienstra
Ultrasound Applications Specialist
International Sales Channel Manager
SDT North America

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