Miura Ultra-Low NOx Modular On-Demand Steam Boilers


Reduced Fuel Consumption, Far Fewer Emissions, and Reliable Operation All Cited as Major Benefits

ATLANTA, GEORGIA - Located in the heart of Houston, the sprawling 150-acre campus of Texas Southern University comprises more than 40 buildings housing nine different schools and colleges. Home to more than 9,500 students and 1,500 faculty and staff, the TSU campus includes academic and administration buildings, dormitories, arts centers, a health and physical education complex, and apartment-style living and recreational facilities. Hot water and - during winter months - steam heat is piped to these buildings from two central steam plants via underground tunnels. Recently, one of the plants was upgraded with the installation of four gas-fired LX-200 boilers from Miura, the world leader in ultra-low NOx modular on-demand steam solutions. According to Tim Rychlec, TSU's Executive Director of Facilities and Maintenance Services, the Miura boilers have brought numerous benefits in terms of convenience, reliability, "green" operation, and - most important - economy.

"We were spending around $1.2 million annually on natural gas consumption with our old fire-tube boilers, but that has dropped to about $400,000 since the Miura boilers were installed," Rychlec says. "Installation of the Miura boilers provides a 66 percent reduction in natural gas usage and it has also increased our overall steam production. We no longer have problems getting steam to any of the buildings on campus."

Comprising a smaller footprint than traditional fire-tube boilers, Miura boilers are microprocessor-controlled for precision operation, and employ a unique "once-through" fin-tube design that conserves fuel, saving an average of 20 percent annually on fuel costs over other boiler designs for typical installations. Miura boilers also produce fewer emissions than conventional boilers, outputting reduced levels of nitrogen oxides (NOx), a major contributor to air pollution, as well as carbon dioxide (CO2), the most prevalent of greenhouse gases. Miura boilers achieve low-NOx performance by reducing the temperature of the boiler's flame, which in turn reduces the amount of excited nitrogen atoms available to bond with oxygen to form nitrogen oxides. As a result of this, NOx emissions are reduced to around one-quarter of what traditional fire-tube boilers emit. This enables Miura boilers to comply with even the most stringent air-quality regulations. With regard to reduced CO2 emissions, Miura's technology leverages superior operating efficiency to contribute significant carbon abatement with a payback.

On-Demand Steam

Miura's exclusive technology produces BHP outputs comparable to much larger units, and - in addition to reducing emissions and energy consumption - Miura's design also enables its boilers to go from a cold start to full steam in less than five minutes. This on-demand steam-generation performance is easily scalable to very large output capacity applications by utilizing its modular "MI" system, in which multiple Miura boilers can be sequentially staged on or off as needed to match load fluctuations, as opposed to consuming energy while constantly idling in stand-by.

"Miura's on-demand steam capabilities are important to us," Rychlec explains. "Last winter was the coldest we've had in quite a few years. We had a long stretch of below-zero temperatures and a lot of icing conditions, but every morning we were able to start all four Miura boilers at once and warm our structures very quickly because of the on-demand steam feature, which made a huge difference. On the busiest days we'll have three of the four Miuras running, and by the middle of the afternoon it's pretty much staged down to one or two."

"The Miuras actually boil themselves down, and rotate run time among the four of them so there is an even amount of run time on each," Rychlec adds, referencing Miura's MI Controller system, a built-in "master" controller that sequentially turns TSU's four Miura LX-200 steam boilers on or off to precisely match prevailing load patterns. This achieves the highest possible in-service efficiencies, which is a measure of overall boiler performance (regardless of load profile) that takes into account all factors of boiler operation, including combustion efficiency, thermal efficiency, fuel-to-steam efficiency, etc.

"With the old fire-tube boilers our steam pressure was usually somewhere between 90 and 40 lbs.," Rychlec continues. "It would cycle back and forth, and the variations in steam pressure would sometimes cause problems with getting the condensation to come back. The Miura boilers, however, automatically cycle and enable us to control humidity and temperature in our buildings much more effectively. Now we set our steam at 70 lbs. and it has run consistently at that pressure for the past year with no deviation. We're even using less water because you don't need as many blow-downs."

Diagnostics and Automation

Control of Miura's individual modular boiler units is driven by the BL Micro Controller boiler control system, which keeps track of multiple individual monitoring points. This advanced diagnostic system can identify any potential challenge to smooth operation and recommend a solution on an easy-to-read display. A "sliding-window feature" records events four seconds before they occur for fast and effective trouble-shooting. This system can also be accessed via the Internet (Miura Online Maintenance, or "MOM") for remote monitoring and diagnostics.

"We have MOM tied to our campus automation system and can access the boilers remotely through a VPS [virtual private server] and secure VPN [virtual private network]," Rychlec says. "This has made things a lot better in our whole HVAC world. Temperatures are more stable inside classrooms and throughout the university. We can see how the buildings are doing, and we can even start a boiler if needed, which is pretty handy. It not only tells you if something is wrong, it tells you what to do, which has made our lives a lot easier by reducing our overall workload. Our maintenance is now just a couple of hours a month."

"We have more capacity than we will ever need, which is a good thing," Rychlec adds. "The university is getting ready to add additional structures, but we won't have to upsize the Miura steam plant because we have more than enough capacity right now. Not only that, but we put four Miura boilers and a feed tank in the same footprint that just one of the old fire-tube boilers used to occupy. Now we have this huge extra space in our central plan that we can use for other things. Plus, the reliability of our Miura boilers allows our steam engineer to get more done."

Rychlec notes that the contractor for TSU's Miura steam plant was Burner Combustion (Houston), with installation by Fort Bend Mechanical (Stafford TX). He adds: "Miura is more reliable and robust system by far. We're looking at Miura boilers for the university's other steam plant as well."

About Miura Boiler

Miura Boiler was founded in 1927 and has grown to become one of the largest industrial steam boiler manufacturers in the world. In 2009, Miura opened a new U.S. manufacturing facility in Polk County, Georgia. For more information on Miura Boiler, call in the USA 1-888-309-5574. In Canada call 1-800-666-2182. Visit Miura online at: www.miuraboiler.com.

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