Virginia Public Utilities District Steam Upgrades

Challenge

Virginia Public Utilities (VPU) provides district steam heat to multiple areas throughout the City of Virginia, Minnesota. VPU operated multiple coal-fired, high-pressure steam boilers to deliver reliable district steam, producing 600 pounds-per-square-inch gauge (PSIG) steam. The coal-fired boilers had proven to be inefficient, complex to operate, and difficult to maintain. The coal-fired system had limited turn-down and performed poorly at low load conditions.  As such, VPU could not produce medium-pressure steam for low-demand heating needs. To address this issue, VPU hired SEH to develop plans for a new medium-pressure boiler plant that could supplement their high-pressure system and provide means of steam production when the coal-fired boilers were down, and heating demand was low.

Solution

SEH worked with Virginia Public Utilities to design a new medium-pressure boiler plant to supplement their high-pressure coal-fired system. Through the design-build process, SEH developed plans and specifications to convert a decommissioned turbine room into a new boiler room equipped with dual 1500 horsepower gas-fired boilers, a deaerator, and a feedwater pumping system. A new steam header and branch piping were also included to incorporate the new gas-fired system into the existing steam piping distribution system. A new combined boiler stack and combustion air system was designed to ensure the boiler plant operated safely and efficiently. The SEH team provided mechanical, electrical, and structural design, as well as air permitting and environmental review.