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IMPROVED GAS DISTRIBUTOR FOR FLUIDIZED BEDS WITH HIGH EROSION RESISTANCE

IP.com Disclosure Number: IPCOM000234007D
Publication Date: 2014-Jan-07
Document File: 3 page(s) / 379K

Publishing Venue

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Abstract

Gas-solid fluidized bed reactors have been widely used in the chemical and other industries for both catalytic and non-catalytic reactions. In such reactors, gaseous feed(s) (such as reactants) need to be uniformly distributed into the reactors via flow distributors. Various types of gas distributors can be employed. One of the commonly used distributors utilizes diffuser pipes where the gas flows upward through many diffuser pipes into the particle beds. At the bottom of each diffuser pipe, there is a orifice with the hole size smaller than the pipe diameter. This orifice size controls the total pressure drop and the gas flow uniformity. A commonly encountered problem is the erosion of the diffuser pipes, particularly around the orifice holes. Reduction in erosion can be achieved by modifying the bottom of the diffuser pipe and changing it from an orifice structure to a gradula internally tapered structure.

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IMPROVED GAS DISTRIBUTOR FOR FLUIDIZED BEDS WITH HIGH EROSION RESISTANCE

Gas-solid fluidized bed reactors have been widely used in the chemical and other industries for both catalytic and non-catalytic reactions.  In such reactors, gaseous feed(s) (such as reactants) need to be uniformly distributed into the reactors via flow distributors.  Various types of gas distributors can be employed.  One of the commonly used distributors utilizes diffuser pipes (also called shrouds), where the gas flows upward through many diffuser pipes into the particle beds.  At the bottom of each diffuser pipe, there is a orifice with the hole size smaller than the pipe diameter.  This orifice size controls the total pressure drop and the gas flow uniformity.  Please see the following figures for details.

However, a commonly encountered problem is the erosion of the diffuser pipes, particularly around the orifice holes.  We believe that the cause of the erosion is the high-speed jet flow passing the orifice hole, which creates recirculation zones (i.e., vortexes and eddies).  These recirculation zones trap solids and aggressively erode both the orifice and the bottom of the pipe, in  a similar mechanism to that of “sand-blasting.”   Reactors often need to shut down after only a short period of operation for the repair of the distributor diffusion pipes.  Thus, it is desired to develop a type of gas distributor for fluidized bed reactors with erosion resistant diffuser pipes, which allows a much longer operation period without repair or replacement.

This invention is about modifying the bottom of the diffuser pipe,...