Device for unloading catalyst from a reactor vessel

1. A method for unloading particles from a plurality of vertical chemical reactor tubes, comprising the steps of:

releasably fixing a frame adjacent to the bottom of a first vertical reactor tube;

providing a fish tape mounted on said frame for substantially linear, upward and downward motion relative to said frame, said fish tape having first and second ends;

aligning the first end of the fish tape with the bottom of the first vertical reactor tube;

using an automated controller to control a reversible drive repeatedly to advance the fish tape upwardly into the first vertical reactor tube until sensing when a first end of the fish tape has contacted the particles and to retract the fish tape downwardly in response to sensing when the fish tape has contacted the particles to allow the particles to fall out of the bottom of the first vertical reactor tube.

2. A method for unloading particles from a plurality of vertical chemical reactor tubes as recited in claim 1 , and further comprising the steps of sensing the motion of said fish tape and transmitting the sensed information to the art automated controller; and

using the automated controller to control the reversible drive in accordance with a pre-programmed algorithm which takes account of the sensed information.

3. A method for unloading particles from a plurality of vertical chemical reactor tubes as recited in claim 1 , and further comprising the step of using the reversible drive to retract the fish tape at a speed that is at least twice the speed at which the fish tape was inserted for any given elevation within the reactor tube.

4. A method for unloading particles from a plurality of vertical chemical reactor tubes as recited in claim 1 , and further comprising the step of using the reversible drive to retract the fish tape at a speed that is greater than the speed at which the particles fall by gravity.

5. A method for unloading particles from a plurality of vertical chemical reactor tubes, comprising the steps of:

releasably fixing a frame adjacent to the bottom of a first vertical reactor tube;

providing a fish tape mounted on said frame for substantially linear, upward and downward motion relative to said frame, said fish tape having first and second ends;

aligning the first end of the fish tape with the bottom of the first vertical reactor tube;

using a reversible drive repeatedly to advance the fish tape upwardly into the first vertical reactor tube until sensing when a first end of the fish tape has contacted the particles and to retract the fish tape downwardly in response to sensing when the fish tape has contacted the particles to allow the particles to fall out of the bottom of the first vertical reactor tube; and

inserting a second end of said fish tape into a second vertical reactor tube while leaving the first end of the fish tape in the first vertical reactor tube, and then using the reversible drive to drive the second end of the fish tape upwardly into the second vertical tube to contact and dislodge particles from the second vertical tube.

6. A method for unloading particles from a plurality of vertical tubes of a chemical reactor, comprising the steps of:

inserting a first end of a fish tape having a first end and a second end into a first vertical tube; then

moving the first end of the fish tape up and down within the first vertical tube to contact and dislodge particles inside the first vertical tube and to allow the particles to fall out of the first vertical tube; then

while the first end of the fish tape is inside the first vertical tube, inserting the second end of the fish tape into a second vertical tube and moving the second end of the fish tape up and down inside the second vertical tube to dislodge the particles and allow the particles to fall out of the second vertical tube.