Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Fluidized bed
Reexamination Certificate
1998-01-05
2001-05-22
Knode, Marian C (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Fluidized bed
C422S139000, C422S143000, C285S226000
Reexamination Certificate
active
06235246
ABSTRACT:
BACKGROUND OF INVENTION
This invention pertains to fluidized bed type catalytic reactors. It pertains particularly to such reactors having an addition/withdrawal conduit for particulate catalyst extending through a flow distribution grid plate located in the reactor lower portion, with the conduit being sealably attached to the grid plate by a bellows type expansion unit.
A known pressurizable ebullated bed catalytic reactor adapted for operation at elevated temperature and pressure conditions and having a lower grid plate for supporting a bed of particulate catalyst, with the grid plate containing multiple riser tubes each covered by a bubble cap for upward fluid flow is generally disclosed by U.S. Pat. No. 3,475,134 to Weber et al. Particulate catalyst is periodically added to and withdrawn from the reactor ebullated bed through an elongated conduit extending upwardly through the reactor lower head and through the grid plate. From past operating experience, such conduits have been a problem because they sometimes fail prematurely near the grid plate due to severe erosion by the randomly moving catalyst particles in the ebullated bed. Such erosion by the catalyst particles is apparently caused by hydrogen gas passing at high velocity through gaps which sometimes occur in a split flange type seal which is usually used around the conduit above the grid plate, for permitting necessary vertical thermal expansion movement of the conduit relative to the grid plate. Because of these undesired erosion problems in such reactors, an improved configuration for sealably attaching the catalyst addition/withdrawal conduit to the reactor grid plate is needed.
SUMMARY OF INVENTION
This invention provides a pressurizable fluidized bed catalytic reactor having an innovative construction for sealably attaching an elongated catalyst addition/withdrawal conduit to a flow distribution grid plate in the reactor lower portion, by providing a concentric bellows type expansion unit located adjacent to the outside surface of the conduit portion which protrudes through the grid plate and into the reactor catalyst bed. The invention includes the pressurizable reactor vessel having the grid plate fixedly mounted transversely in the reactor lower portion for supporting a bed of particulate catalyst, and arranged for upward fluid flow distribution therethrough. The reactor has the elongated catalyst addition/withdrawal conduit extending through the reactor lower head and upwardly through the grid plate into the catalyst bed, and a concentric bellows unit is sealably attached at its lower end to the grid plate and is sealably attached at the bellows unit upper end to the conduit. The reactor is adapted for sustained operation at elevated temperature of 600-900° F. and pressure of 500-3000 psig. The bellows unit of this invention is suitable to accommodate both radial and vertical thermal expansion of the elongated conduit relative to the grid plate.
The bellows type expansion unit configuration of this invention advantageously provides a flexible and reliable sealing means around the catalyst addition/withdrawal conduit portion extending above the grid plate. The bellows unit cost can be traded off against the cost of a previously used split flange joint sealing arrangement for which undesired erosion problems have been experienced.
REFERENCES:
patent: 3475134 (1969-10-01), Weber et al.
patent: 4095974 (1978-06-01), Matovich
patent: 4317798 (1982-03-01), Worley
patent: 4348354 (1982-09-01), Artaud et al.
patent: 4687639 (1987-08-01), Whiteside, II
Doroshenk Alexa A.
IFP North America, Inc.
Knode Marian C
Ritter John F.
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