Oil, Gas and Industrial

Industrial Vessel Fabrication

Challenge
To heat and dry the interior of large steel vessels in diameter of 30’ and 250’ long, during the manufacturing process in winter ambient temperatures of minus 30 degrees C. Deliver air quality without moisture and toxic gasses for crews working on the vessel.

Objective
  • Heat and maintain a target temperature of 5 degrees C for vessels in structures which housed these vessels
  • Provide dry clean air and ventilation which facilitated welding and instrument operation
  • Provide a heat source which was flexible, fuel-efficient and convenient to operate
Solution
A system was designed with three capabilities:
  1. An extra heavy duty air to air indirect-fired heater was located outside the structure to duct dry pressurized heat into the vessel at 210 degrees F, with a 240 degree temperature lift over outside ambient air temp and 4,000 cfm of air movement.
  2. A re-circulating duct/damper system was incorporated to reheat interior air through the heating unit when not welding.
Result
  • The ICS system successfully met the project requirements of providing clean air, acceptable working temperatures, dry air (low relative humidity) and fuel efficiency.
  • This one-unit system replaced 4 smaller direct-fired open flame systems which collectively could not provide the same evenly distributed heat and air movement
  • The ICS system eliminated the need for cold make-up air – required by open flame.
  • The high temperature resulted in a dry air supply of 2% to 4% relative humidity.
  • Re-circulate interior air back through the heater. When not welding, interior air could be re-circulated back through the heating unit to improve heating efficiency and reduce fuel consumption.
  • This industrial-scale system provided adequate heat, pressurization and dry air
  • The ICS system was considerably more convenient to operate for the contractor. The ICS system had a run time of 65 hours and consequently, was re-fuelled once every two days. The four open-flame units each had to be re-fuelled daily.
  • Interior toxic combustion gasses were eliminated, which removed the need for cold external make-up air. Fuel savings without need for makeup air or reduction in ventilation
  • Interior toxic gasses were eliminated by installing an air to air indirect-fired heater outside of the structure. Heat was ducted into the interior of the structure. Interior toxic combustion gasses were eliminated, which removed the need for cold external make-up air.

Additional Resources