As the president of Preferred Utilities Manufacturing Corporation, Redding, CT-based industrial equipment professional David Bohn led the fuel oil and boiler equipment manufacturer to a 380 percent increase in annual corporate revenue. In addition to his administrative accomplishments, David Bohn has expertise in multiple technical areas including the prevention of dry firing in boilers.
A big problem in the boiler industry, dry firing occurs when something interferes with the regular supply of boiler feedwater. If the boiler runs out of water, and safety features fail to engage, steam pressure will soon drop to zero. Although the true cause of this drop is a complete lack of boiling water (and, therefore, steam), the boiler will automatically attempt to make up for the lack of steam pressure by increasing internal temperature. Within minutes, high temperatures can irreparably damage the boiler due to a phenomenon called metal creep.
Boiler owners and/or operators can reduce the risk of dry firing by ensuring that advanced safety controls are set to trip the boiler offline when water supply is interrupted. They can also prevent dry firing by installing header-pressure transmitters on variable-speed-drive pumps, monitoring stack temperature closely, and performing regular automated low-water cutout tests.
Preferred Utilities Manufacturing Corporation
Since 1995, David Bohn has served as president of Preferred Utilities Manufacturing Corporation in Danbury, near Redding, CT. David Bohn draws on a 30-year history with the Redding, CT-area company, during which time he has gained an in-depth knowledge of boilers and the risk of dry-firing.
A boiler depends on balanced temperature and pressure levels to operate correctly. If a boiler ever becomes empty of water, pressure drops to zero and the boiler works harder to restore pressure. The lack of water leads the boiler to overheat and can permanently damage the metal mechanism, assuming an emergency feedwater pump does not first introduce cold water to the hot metal and cause an explosion.
Testing and monitoring are key to the prevention of dry-firing. Contemporary controller systems have mechanisms for monitoring stack temperature, so that excess heat would prompt a shutoff. Similar shutoff procedures may occur with automated low water testing.
Plant owners can also help to prevent dry-firing by installing redundant feedwater pumps, which engage in the case of pump failure and can help the mechanism avoid drying. Similarly, a feedwater header-pressure transmitter can emit an alarm and engage a second pump if pressure drops, thus reducing the chance of a dry boiler.
Preferred Utilities Manufacturing Corporation
David Bohn is a Redding, CT, executive who directs Preferred Utilities Manufacturing Corporation as president and offers a host of energy-efficient products ranging from industrial boilers and burners to combustion controllers. David Bohn and his Redding, CT, team oversaw a major coal-to-natural-gas boiler conversion process that reflected a 2012 mandate for the Wright-Patterson Air Force Base to be brought under new U.S. Environmental Protection Agency emission limits.
The Dayton, Ohio, base has historically operated using coal- and natural-gas-fired boilers. The coal-fired boilers did not come in under new Maximum Achievable Control Technology (MACT) standards in areas such as particulate and mercury. With compliance deadlines fast approaching, major conversions of two coal-fired boilers were initiated, as well as the conversion two coal-powered high-temperature-hot-water (HTHW) systems. The other units were planned for demolition.
When completed, the upgrades significantly decreased pollutant emissions and reduced the amount of carbon dioxide released by 50 percent. With the boiler modifications having completed last year, they are now fully operational and helping meet sustainability goals.
API Inject-Aire Burner
Based in Redding, CT, David G. Bohn serves as president of Preferred Utilities Manufacturing Corporation, guiding a Danbury company that provides power plant equipment engineering and manufacturing solutions. Among David G. Bohn’s successfully completed projects outside of Redding, CT, is the implementation of a new low-emissions, high-efficiency API Inject-Aire burner at Stapleton Houses, which are run by the New York City Housing Authority (NYCHA).
The burner is pioneering in its compliance with recently instituted municipal laws that mandate significant carbon emissions reductions over a three-year period. Specifically, electricity consumption reductions of up to 85 percent compared with burners previously purchased by NYCHA are sought.
The API Inject-Aire burner’s high fuel efficiency technologies include those that reduce boiler heat loss through eliminating half of the start-up and shut-down cycles that are most energy intensive. With the durable burners lasting longer than boilers, there is no need for expensive retrofits throughout the system lifecycle. The burners come with industry leading component warranties to ensure that any issues experienced are quickly resolved in ways that keep the system running.