Category Archives for Operation

Onstream Water Washing

Water washing of convection section tubes externally while onstream is a viable method of removing deposits and improving furnace efficiencies. Good candidates for onstream water washing of convection section tubes are crude heaters, boilers, FCC feed heaters, coker heaters, and … Continue reading

18. May 2018 by sam
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Soot Blowing on Oil Conversions

On oil conversions, some existing convection tubes may have to be removed to provide lanes for the soot blowers. Some undesirable loss of surface results. Also, the tall, thin, tightly spaced fins typical of gas fired convection sections cannot be … Continue reading

18. May 2018 by sam
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Proper Location of Soot Blowers

The effectiveness of a soot blowing system depends on the spacing of the soot blowers with respect to the convection tube banks. The soot blower supplier should review the furnace designer’s proposed soot blower locations. Although penetration from the end … Continue reading

18. May 2018 by sam
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Soot Blowing

In order to maintain optimum heat transfer rates in the convection section, the outside surface of the tubes and fins (or studs) should be free of soot, ash and other deposits. On line cleaning of the outside of the convection … Continue reading

18. May 2018 by sam
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Monitoring for Hot Spots

We use visual checks, thermocouples on tube skins and IR thermography to monitor for hot spots. Thermocouples have some limitations. They are placed where the designer anticipates the tubes will run the hottest; e.g., we expect to see one on … Continue reading

18. May 2018 by sam
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Hot Spots – Internal Causes

Loss of Flow The most frequent cause of hot spots and resultant tube ruptures is loss of flow and our inability to respond fast enough to prevent the resulting temperature rise. When we lose flow inside one of the tubes … Continue reading

18. May 2018 by sam
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Hot Spots – External Causes

Flame Impingement The only cause of hot spots that can be fixed by changes in burner design, operation or maintenance is flame impingement on the tubes. Possible hardware-related causes are: • Burner plugging, • Burner misalignment, • Individual tip misalignment, … Continue reading

18. May 2018 by sam
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Furnace Monitoring and Tuning

Tuning is the careful reduction of excess air to the target range to improve efficiency during steady operation. Tuning is essentially monitoring and adjusting the stack O2 level. Figure 1000-4 provides an overview of the monitoring and tuning step in … Continue reading

18. May 2018 by sam
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Determining an O2 Target Range

Targeting is the process of determining the stack O2 level to use during normal furnace operations that allows for maximum furnace efficiency. The targeting process is shown in Figure 1000-2. Targeting is accomplished in three phases: • burner balancing • … Continue reading

18. May 2018 by sam
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Furnace Tuning and Efficiency

This section summarizes an operator training course called “Safe and Efficient Operation: Tuning a Furnace for Efficiency,” taught by Nick Brancaccio of CRTC (CTN/510 242-2350). The training material is available as a kit which includes four videos, flip charts, handouts, … Continue reading

18. May 2018 by sam
Categories: Operation | Leave a comment