Steam methane reformer tube outlet assembly
OwnerKwamina Bedu-Amissah, Troy M Raybold +2inventors
InventorsKWAMINA BEDU-AMISSAH, TROY M RAYBOLD, BOBBY L RANSON, KANG XU
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Abstract
The present invention relates a steam methane reformer tube outlet assembly and a method of assembling or retrofitting same. More specifically, it relates to an exposed flanged tube outlet of a reformer designed to mitigate metal dusting corrosion, dew point condensation-related metal fatigue and cracking, and over-temperature induced metal failures such as hydrogen attack.
Claims14
A flanged tube outlet assembly of a steam methane reformer assembly comprising:
- at least one or more reformer tubes having an inlet for allowing a process gas to be introduced into said tube outlet assembly for the removal of said process gas, wherein said process gas exiting an outlet port is syngas,
- said tube outlet assembly is disposed outside the confines of the reformer and includes a reformer tube having an interior space accommodating an internal insulation can therein wherein said insulation can is fitted in the interior space of the reformer tube, and the exterior of said reformer tube is covered with insulation extending in close proximity to the tube-flange weld neck;
- the outlet port disposed upstream of the distal end of said insulating can for delivering said syngas to downstream process units, and
- said insulation can is connected to a blind flange and extends into the reformer tube toward the outlet port, wherein the gap between the can and the interior of said reformer tube is larger at the distal end than at the blind flange end.
A flanged tube outlet assembly of a steam methane reformer assembly comprising:
- at least one or more reformer tubes having an inlet for allowing the process gas to be introduced into a tube outlet assembly for removal of the process gas, wherein said process exiting an outlet port is syngas,
- said tube outlet assembly is disposed outside the confines of the reformer and includes a reformer tube having an interior space accommodating an internal insulation can therein wherein said insulation can is tapered or stepped in the interior space of the reformer tube and wherein the exterior of said reformer tube is covered with insulation extending in close proximity to the tube-flange weld neck;
- the outlet port is disposed upstream of the distal end of said insulation can for delivering said syngas to downstream process units, and
- said insulation can is connected to a blind flange and extends into the reformer tube toward the outlet port and securely connected to the blind flange, wherein the gap between the can and the interior of said reformer tube is in the range between about 0.1 to 0.5 inches at the blind flange end of said tube outlet, and 0.1 to 1 inches at the distal end, allowing a larger volume of hot syngas to be maintained at the distal end of the gap so the tube metal temperature in the vicinity of the distal end of the can is above metal dusting favorable temperatures, yet regulating the flow of hot gas towards the flange to maintain the whole length of the tube outlet above the syngas dew point temperatures to eliminate condensation/evaporation thermal cycling induced fatigue cracking while lowering the flange temperatures to minimize occurrence over-temperature induced metal failures.
Processing a hydrocarbon feedstock in a can or bottom fired stream methane reformer, comprising:
- reactor tubes with a coating, an aluminum diffusion coating applied by pack cementation, wherein the coating is applied to the inner walls of the tube outlet assembly extending from the distal end down into the tube a distance of 72 inches, and having a thickness of 10-300 μm, to minimize tube exposure to carbon supersaturated environments and substantially reduce metal dusting at temperature ranging from about 900-1400° F.
A method of preventing metal dusting corrosion of a reformer tube utilized in a steam methane reformer application, comprising:
- introducing a hydrocarbon feedstock at the bottom of the reactor tubes, wherein an upper portion of the inner walls of a tube outlet assembly is coated with a composition 30-40 wt % Al, which is resistant to metal dusting.
Dependencies are inferred from the claim text.