Patent ID: 7279145

Claim:
In a reactor having a central draft tube located within said reactor, at least one impeller located within said draft tube, an annular space between the draft tube and a wall of the reactor, and a fluid flow path in only one direction within the draft tube and only countercurrent flow, relative to the direction of fluid flow within the draft tube, through the annular space, the improvement comprising a) a catalyst bed for a solid catalyst located within said annular space; b) a filter element in said annular space positioned downstream from said catalyst bed relative to the direction of fluid flow through said annular space, said filter element having pores therein to allow fluid flow through said filter element, said pores of sufficiently small size so to substantially prevent catalyst particles from leaving said catalyst bed; c) a second filter element having pores therein to allow fluid flow through said second filter element in said annular space upstream from said catalyst bed relative to the direction of fluid flow through said annular space; said reactor having at least one inlet for an inlet feed stream and at least one product outlet for a product stream, wherein the catalyst bed is contained with a catalyst basket located within said reactor, said catalyst basket comprising: i) a central tube and a larger annulus-defining tube; and ii) a top ring and a bottom ring, each of said top and bottom rings fixed to both said central tube and said annulus-defining tube, the space between said central tube and said annulus defining tube defining an annular space suitable for receiving a charge of said solid catalyst; wherein said filter element is positioned above said top ring or within said to ring such that fluid entering said annular space passes through said first filter element, said second filter element is positioned below said bottom ring or within said bottom ring such that fluid leaving said annular space passes through said second filter element, and said central tube surrounding said draft tube or comprising said draft tube.