High Velocity Combustion heating systems for the purposes of Field Heat Treatment consist of a Gas / Valve Train, High Velocity Burner, high volume pressure Blower, and interconnecting control cabling, flexible gas hoses, and air ducts.
These HV Combustion heating systems are used in a variety of Field Heat Treatment applications, ranging from relatively low-temperature epoxy cures of large petrochemical storage tanks, to high-temperature PWHT stress reliefs within small temporary furnaces and In-situ PWHT of large multi-story petrochemical towers, to refractory dry-outs and molten metal foundry and glass furnace start-up applications.
These HV Combustion systems are dual fuel for Natural Gas or Liquid Propane. In the even that Propane is being used, Propane vaporizers will be also need to ensure that the proper flow rate is accomplished.
A Gas / Valve train is an assembly of piping, control and safety valves, and a flame safety system which is needed to safely control the pressure and flow rates of fuel to the High Velocity Burner, and monitor flame safety, in accordance with National Fire Protection Association (NFPA) and American and Canadian Gas Association guidelines.
Safety-interlocked pressure, flow, and flame control components ensure that the system is operated in a safe manner and provide feed back to the Combustion Technician during equipment start-up and operation.
Portable gas trains are generally housed in wheeled cabinets, and are available in a variety of sizes and BTU capacities. An automatic gas train utilizes a closed-loop microprocessor temperature controller, while a manual gas train requires operator interaction, and is best suited for such thermal processes as refractory dry-outs and furnace stress reliefs, where an array of thermocouples is needed to affirm temperature uniformity.
All burners develop high-velocity, low-luminescent flames varying in length from 3- to 8-ft long and 6- to 15-inches in diameter, depending on burner size and thermal power capacity. Due to the 100% turn down ratio available on the gas trains there are typically only 4 burner sizes required for the majority of applications, with thermal power capacities of 1, 3, 6, and 10 MBtu/hr. All are equipped with ultraviolet flame sensors and remote ignition transformers.
High velocity burners utilize high-volume, pressure blowers for combustion air, as a means of enhancing turbulence and convective heat transfer. This results in most applications being characterized as lean or excess-air operation, as opposed to stoichiometric, or fuel-rich operation. Consequently, the products of combustion are minimized and diluted.
Typically for a 10 MBtu/hr Burner, a 2,200-scfm (standard cubic feet/min) blower, capable of creating static pressure of 24 in. WC (inches of water column), powered by a 15-HP 3-phase electric motor is used. Each blower consists of a motor, starter, control panel, airflow control valve, and air pressure switch.