These heaters can have vertical tube coils, horizontal tube coils or Arbor coils depending on your specific requirements and most suitable design solution to meet them.
In case of vertical tube double fired heaters, vertical radiant tubes are arranged in a single row in each combustion cell (there are often two cells) and are fired from both sides of the row. Such an arrangement yields a highly uniform distribution of heat-transfer rates about the tube circumference.
Another variation of these heaters uses multilevel side-wall firing, which gives maximum control of the heat-flux profile along the length of the tubes. Multi-level side-wall firing units are often employed in fired-reactor services and in critical reactor-feed heating services. In addition to the twin-cell furnaces, single cell models are available for smaller duties. As a group, these represent the most expensive fired heater configuration. The typical duty range for each cell runs from about 20 to 125 million Btu/h.
In case of horizontal tube cabin heaters, the radiant tube coils are arranged horizontally so as to line the sidewalls of the combustion chamber and the sloping roof. The convection section tube coil is positioned as a horizontal bank of tubes above the combustion chamber. Normally the tubes are fired vertically from the floor, but they can also be horizontally fired by sidewall-mounted burners located below the tube coil. This economical, high-efficiency design currently represents the majority of new, horizontal tube, fired heater installations. Duties run from about 10 to 100 million Btu/h.
Heater with Arbor tube coil is a specialty design in which the radiant heating surface is provided by U-tubes connecting the inlet and outlet terminal manifolds. This type is especially suited for heating large flows of gas under conditions of low temperature drop. Typical applications are found in petroleum refining, where this design is often employed in the catalytic-reformer charge heater and in various reheat services. Firing modes are usually vertical from the floor, or horizontal between the riser portions of the U-tubes.
Among horizontal and vertical tube configurations, the following types exist:
- Horizontal Tube Hip-Frame
- Horizontal Tube Flat Roof
- Horizontal Tube Twin Cell
- Vertical Tube Multi-Cell
- Center Tube Double Fired
- Multi-Cell Horizontal and Vertical Tube
The type of heater offered is carefully selected to feature low capital cost, high efficiency, close control and trouble free operation. We will consider all of your requirements, and make recommendations based on our experience for the most suitable design.