Background
The U.S. Navy requires temporary steam supplies under many different circumstances. Most common among them are as back-up to facility boilers at Navy installations throughout the world, and as alternate steam sources for ships in port when their boilers are undergoing repairs. Transportability, meeting stringent low NOx regulations and compliance with MIL-SPECs are just a few of the many requirements these systems meet.

Scope of Supply
Nationwide Boiler received a contract from the U.S. Navy Facilities Command to provide eight complete boiler systems, model NBI Low-NOx Transportable Steam Plant. The contract included the following tasks: conceptual and detail design engineering, including CAD drawings, equipment selection, production fabrication and assembly, efficiency and emission compliance testing, quality assurance, and project engineering and management. All of these tasks were performed in full compliance with appropriate MIL- SPECs and contract requirements.

Equipment Description
The NBI Low-NOx Transportable Steam Plant is a self-contained unit mounted in a metal van-type enclosure attached to a steel base frame. The plant is designed to be shipped by rail, sea or over-the-road and to operate continuously with ambient temperatures ranging from -250 F to 110 F at elevations from sea level to 5,000 feet The physical dimensions of the complete plant are 50 ft.-9 in. long, 10 ft.-6 in. wide, 11 ft.-8 in. high (without stack), and 94,000 Ibs. dry weight. Height with the stack installed is 20 ft.-3 in., and wet weight is 137,000 Ibs. All control panels as well as a workstation for operating personnel are located inside the enclosure.

System Components
The major components of the NBI Low NOx Transportable Steam Plant include:

• Fire-tube boiler rated at 5,000- 20,000 Ibs./hr net output at 15-160 psi. saturated, including safety valves, automatic level and pressure controls
• Low NOx burner capable of firing natural gas, propane or propane air. The burner utilizes induced flue gas recirculation to limit NOx emissions to below 30 ppm
• Make-up, deaerator/condensate and feedwater system with pumps, valves, controls and instrumentation necessary to receive returning condensate, deaerate make-up water, and pump feedwater to the boiler
• A 480VAC, 3 phase, 60 Hz, 225 amp electrical distribution system

Other components included in each system are:
• Boiler blowdown and heat recovery system
• Natural gas/propane supply system
• Combustion air system and flue gas recirculation system
• Chemical treatment system
• Heating and ventilating system
• Water sample system

In addition to the systems listed above, each plant includes personnel support and safety equipment, and other ancillary devices necessary to assure safe and reliable plant operation.