Pinned furnace tubes
AssigneeNOVA Chemicals (International) S.A.
InventorsJeffrey Stephen Crowe, Mark Andrew Taylor
Life of this patent
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Abstract
In an embodiment of the invention, furnace tubes for cracking hydrocarbons having a longitudinal array of pins having i) a maximum height from 0.5-1.3 cm; ii) a contact surface with the tube, having an area from 0.1%-10% of the tube external surface area iii) a uniform cross section along the length of the pin. (i.e. they are not tapered); and iv) a length to diameter ratio from 1.5:1 to 0.5:1 have an improved heat transfer over bare fins and reduced stress relative to a fined tube.
Claims22
A tube for use in the radiant section of a furnace for cracking hydrocarbons to produce olefins having on its exterior surface a series of pins in one or more linear arrays parallel to the longitudinal axis of the tube, said pins having:
- i) a maximum height from 0.8 cm to 1 cm (paragraph 43);
- ii) a contact surface with the tube, having an area from 0.1%-10% of the tube external surface area;
- iii) a uniform cross section along the length of the pin;
- iv) length to diameter ratio from 1.5:1 to 0.5:1;
- v) a distance between consecutive pins within a given linear array is from 0.1 to 5 times the diameter of the pin;
- and
- vi) from 2 to 6 linear arrays of pins radially spaced from 180° to 20° apart.
Dependencies are inferred from the claim text.