QBJ - Indirect Line Heater
The QBJ indirect line heater is a sophisticated system for the indirect heating of gases, incorporating various components such as a high-pressure gas coil, heater shell, firetube, expansion tank, exhaust stack, and burner control system. This system leverages a firetube burner, which indirectly heats a solution typically made of water and ethylene glycol. This heated solution then transfers heat to the gas coil through convection, safely separated from the flame to prevent risks. The firing rate is meticulously regulated using either pneumatic or electronic temperature controllers to maintain desired temperatures of the outlet gas and heat media solution. Depending on the design, burners can be natural draft with 65% to 70% efficiency or forced draft reaching efficiencies of 75% to 85%. Gas coils are crafted according to ASME standards ensuring they meet specific service pressures and temperatures, while heater shells follow API-12K specifications. Thermally insulated heater shells enhance efficiency, and an expansion tank mitigates volume changes, ensuring system integrity and reducing the risk of corrosion during non-operational periods.
The QBJ indirect line heater is an indirect heating system composed of a high pressure gas coil, a heater shell, firetube, expansion tank, exhaust stack & burner control system. The firetube burner and control system via combustion in the firetube, heats the heat media solution (normally H2O & EG). The exhaust gas are conveyed out by the exhaust stack. The heated solution transfers the heat via convection to the gas coil and thereby the gas as it flows through the coil. This indirect heating system is inherently safe in that the flame is always separated from the gas coil by a H2O / EG bath.
The firing rate of the burner is controlled in response to temperature controllers (thermostats) sensing the temperature of the outlet gas and or the H2O / EG bath. Temperature controllers may be either pneumatic or electronic. Burners may be either natural draft (65% to 70% efficient) or forced draft (75% to 85% efficient).
Gas Coils are ASME designed, fabricated (100% radiographed) and stamped for applicable service pressure and temperature.
Firetubes and heater shells are designed and fabricated as per API-12K. Heater shells are normally insulated for greater thermal efficiency.
The expansion tank is sized for 6% of the cold heater volume and provides constant containment for the solution as the heater increases and decreases in temperature. A secondary use of the expansion tank is to maintain a liquid seal above the top of the heater shell during periods of nonuse in order to prevent corrosion to the upper shell.
A low liquid level switch provides for the shutdown of the burner system in the event of a low bath level.
Standard Applications
- City Gate Stations Combustion
- Turbine Plants
- Dehydration Facilities
- Pressure Reduction Stations
Standard Features
- High Thermal Efficiency
- Expansion Section
- ASME Code Construction
- Fuel Gas Preheat Coil
- Insulation with Embossed Aluminum Jacketing
- Regulators
- Stainless Steel Instrument Tubing
- API 12K Construction
- Flame Arrestor
- Temperature Controller
- High Temperature Shutdown
- Stack Down Draft Diverter
Optional Features
- Electronic Pilot Igniter/ Reigniter
- Flame Failure Shutdown
- High Stack Temperature Shutdown
- Low Bath Level Shutdown
- Forced Draft Burners
- Electronic PLC Control Panel
- ASME Code Fuel Gas Scrubber
- Skid Mounted
- Ladder and Platform
- Turbulators