Multiphase reactor design incorporating filtration system for fixed—bed catalyst
View Patent ↗A unique reactor configuration especially suitable for interphase mass transfer and mixing of multiple phases, i.e. gas(es), liquid(s), and solid(s) where reaction is catalyzed by a solid catalyst comprises a draught tube reactor wherein the solid catalyst particles are maintained in an annular space between the draught tube of the reactor and an annulus-defining wall by means of filter elements positioned downstream and optionally also upstream from the catalyst bed.
1. In a process for the epoxidation of an olefin in the presence of a solid catalyst in a liquid reaction medium, the improvement comprising
epoxidizing said olefin 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, said reactor having
a) a catalyst bed for the 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 top 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,
and separating olefin oxide from the product stream thereof.
2. The process of claim 1 , wherein said liquid reaction medium comprises an oxygen-containing solvent.
3. The process of claim 1 , wherein said solid catalyst comprises a titanium silicalite catalyst.
4. The process of claim 3 , wherein said inlet feed stream comprises hydrogen and oxygen and said solid catalyst comprises titanium silicalite treated to contain a noble metal.
5. The process of claim 3 , wherein said solid catalyst is an agglomerate of the titanium silicalite bound together with a binder.
6. The process of claim 1 , wherein said draft tube contains one or more baffles oriented vertically within said draft tube, and proximate one or more of the impellers.
7. The process of claim 1 , wherein one or more of the inlets terminates proximate to an upstream end of said draft tube, relative to the direction of fluid flow within said draft tube, or terminates within said draft tube.
8. The process of claim 1 , wherein said product outlet is located downstream from said annular space relative to the direction of fluid flow through said annular space.
9. The process of claim 1 , wherein the reactor has a filter support plate positioned intermediate said top ring and said first filter element.
10. The process of claim 1 , wherein the reactor has a filter support plate positioned intermediate said bottom ring and said second filter element.