Firetube having thermal conducting passageways

Abstract

A firetube is immersed in a fluid to be heated and transfers heat from hot gases flowing through the firetube to the fluid surrounding the firetube. The firetube has a plurality of thermally conductive passageways which extend through the firetube for increasing the surface area available for heat transfer. Fluid is conducted through the passageways by a thermosiphon effect resulting from a temperature differential in the vessel, the fluid below the firetube being cooler and denser than fluid above the heat exchanger.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. provisional application 61 / 422,810, filed Dec. 14, 2010, and U.S. provisional application 61 / 434,258, filed Jan. 19, 2011, the entirety of each of which is incorporated herein by reference.FIELD OF THE INVENTION[0002]Embodiments of the invention relate to indirect-fired and direct-fired heat exchangers and more particularly to firetubes installed in process vessels, the firetubes having enhanced surface area for heating process fluids.BACKGROUND OF THE INVENTION[0003]It is known to heat process fluids in a variety of vessels, such as ASME code process vessels, atmospheric bath heaters and tanks. Generally, a heat exchanger is fit within a vessel for heating fluids, such as those commonly handled in oilfield handling and refining operations.[0004]In the oilfield, U-shaped “firetubes”, referred to as U-tube firetubes or U-tubes, are common heat exchangers for use in vessels containing fluids to be...

AI Technical Summary

Benefits of technology

[0011]Advantageously, where process fluids comprise emulsions of water and hydrocarbons having different coefficients causing them to expand and contract at different rates, the expansion and contraction as the fluid enters and leaves the relatively small diameter passageways aids in coalescence of like molecules, which assists in separation of the different constituents a vessel.

Problems solved by technology

Use of round pipe to create the U-tube firetube results in a very inefficient heat exchanger as the surface area presented to the intended fluid is limited.

As a result, a significant amount of the available heat, imparted by the flame, is lost as hot exhaust gases flow through the firetube and up the stack.

Thus, conventional U-tube firetubes are expensive to operate, waste energy used to generate the heat, typically do not optimally utilize the heat generated, and release large amounts of waste gas to the environment.

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