Founded as a one-man operation in 1998 by Robert Krowech, HRST Inc. headquartered in Eden Prairie, Minnesota, U.S.A. specializes in heat recovery steam generators (HRSGs) and waste heat boilers. Today, Krowech continues to serve as president of the company, which has three U.S. locations and capabilities to provide services in nearly every region of the world. Its range of services includes inspection, analysis and design upgrades. Product offerings include retrofit pipe penetration seals and pressure parts.

The Shockmaster Economizer, shown here, features an improved and patented design that promotes uniform water flow and temperatures across each tube within the panel, minimizing pressure part stress.
The Shockmaster Economizer, shown here, features an improved and patented design that promotes uniform water flow and temperatures across each tube within the panel, minimizing pressure part stress.

HRST was recently awarded a patent on one of its pressure parts, the HRST Shockmaster Economizer. Its design improves economizer reliability and provides cost savings for combined cycle power plants by eliminating costly repairs. Various designs of economizers have been in existence for over 100 years. Common problems with traditional HRSG economizers have been tube leaks caused by temperature differentials between adjacent tubes. As a result, these traditional HRSG economizers can under-perform and suffer fatigue cracking. Continuous HRSG cycling increases the risk of the occurrence.

Ken MacKenzie, maintenance superintendent for the city of Medicine Hat, Alberta, Canada, explained typical problems with economizers. “Economizer leaks have been a recurring problem for us over the years. These problems have led to many costly repairs and a significant amount of downtime.” Just over two years ago, MacKenzie began replacing original economizers with the HRST Shockmaster Economizers; he reported that they have not experienced any leaks. This technology has been specified for installation in the construction of its new plant currently under way.

The Shockmaster Economizer design promotes uniform water flow and temperatures across each tube within a tube panel, minimizing pressure part stress. The design also allows complete venting prior to start-up. This technology is well suited for cycling HRSGs and is compatible with partial economizer replacements. Shop modularization yields short retrofit outages. Krowech added, “We are very excited about the HRST Shockmaster Economizer technology. The subtle design changes that we made will change the way combined-cycle power plants maintain and service traditional HRSG economizers. With a price tag that can be recouped within five to six months, and the elimination of both standard repair costs and downtime, we are confident that this technology will quickly be adopted.”

HRST recently received the 2009 Governor’s International Trade Award from Governor Tim Pawlenty of Minnesota for growing international business. HRST has provided services and products to power plants located throughout North America, South America, Australia, the Middle East, Europe and the Far East regions

Source: WWW.DIESELGASTURBINE.COM

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