Jacketed firetube system for a process vessel

Abstract

A jacketed firetube system for use in a process vessel such as a heater or heater / treater has a jacket which extends along the firetube, at a flame inlet end. The jacket can be external to the firetube or internal to the firetube. A heat transfer fluid is circulated along the firetube between the jacket and the firetube for recovering heat from the firetube and reducing the firetube's temperature. The recovered heat is reintroduced into the system.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. provisional application 61 / 434,258, filed Jan. 19, 2011, the entirety of which is incorporated herein by reference.FIELD OF THE INVENTION[0002]Embodiments of the invention relate to firetubes for use in process vessels, such as heaters or heater / treaters used in the oil and gas industry, and more particularly, to apparatus and systems for maximizing heat recovery from the firetube and for minimizing fouling and localized overheating.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 “U” tube heat exchanger is fit within the process vessel. Heat is transferred from the heat exchanger to the process fluids therein for heating the process fluids as part of the handling and refining operation.[0004]In the oilfield, U-tube heat exchangers or U-shaped “firetubes” are common for ...

AI Technical Summary

Benefits of technology

[0010]Embodiments of a jacketed firetube system efficiently utilize and conserve heat within a direct-fired heater and protect the firetube from developing hotspots, by circulating a heat transfer fluid, externally or internally, along at least the portion of the firetube which is at greatest temperature.

Problems solved by technology

Any heat remaining in the exhaust gases is typically lost to the exhaust stack.

In the case of a direct-fired heater vessel, contaminants and particularly the polymers, are susceptible to attaching to the very hot external surfaces of the firetube, resulting in a coating or fouling of the firetube's surfaces and reducing the ability to effectively exchange heat to the process fluids.

Further, in automated operations, as the monitored temperature of the process fluid does not increase to desired operational temperatures or even lowers, the control system increases the burner input in response.

Increased burner input results in a larger flame which can cause flame impingement at inside walls of the firetube, impingement creating localized hot spots.

Hot spots can ultimately result in burn-through of the firetube walls.

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