Category Archives for Design

Piping for Steam-Air Decoking

Removal of coke from the tubes can be accomplished either mechanically with cutters or by steam-air decoking. Both processes yield good results; however, mechanical cleaning is time consuming and results in the loss of tube metal. Steamair decoking rids the … Continue reading

25. April 2018 by sam
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Gas Testing Connection

Prior to operating a furnace, the furnace must be sniffed after purging to detect any combustible gas left in the firebox. Any opening on a furnace can be used for sniffing, however, the locations to be used should be labeled … Continue reading

25. April 2018 by sam
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Purging Steam Manifolds

The piping manifold for purging steam should be designed to provide separate valved lines to the combustion chamber and to each header box of each fired heater. Block valves should be located at grade and a minimum of 50 feet … Continue reading

25. April 2018 by sam
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Purging Steam

Natural draft fired heaters should be provided with a purge steam system to sweep all gases from the heater prior to operation. API 560 requires that piping and connections should be 1½ or 2 inches to each firebox, ¾ inch … Continue reading

25. April 2018 by sam
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Snuffing (Smothering) Steam

As of the 1995 edition of API 560, “Fired Heaters for General Refinery Services,” fired heaters are no longer required to have or use snuffing steam systems. Natural draft heaters are required to have and use purge steam systems and … Continue reading

25. April 2018 by sam
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Transfer Line Critical Velocity

By definition, critical velocity is the maximum velocity that a compressible fluid (a gas or a two-phase mixture) can attain through a pipe of constant cross-sectional area. When critical velocity is reached, downstream conditions will not affect the fluid flow … Continue reading

25. April 2018 by sam
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Transfer Line Sizing

Transfer line sizing should consider pressure drop in the system and velocity of the fluid through the system. See Figure 400-15 for a typical system flow diagram. If the transfer line is too small, a high pressure drop will be … Continue reading

25. April 2018 by sam
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Burner Piping

There are two major requirements to consider in the design of the piping at the burners: Piping must not obstruct access to the burners. Lines should be routed as directly as possible to the burners taking care to observe the … Continue reading

25. April 2018 by sam
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TRC-PdC-Manifolds

It is the function of the furnace to supply stock of a definite temperature. Once this outlet temperature has been reached, heat input must be reduced. This means that the flow of the fuel to the burners, oil and gas … Continue reading

25. April 2018 by sam
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Fuel Gas, Fuel Oil and Atomizing Steam

It is important to understand the basic difference in the use of oil or gas as fuel. While fuel gas can be mixed with air and used as is, fuel oil often must be heated to reach a viscosity suitable … Continue reading

25. April 2018 by sam
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