CCR PLATFORMING CATALYST LOADING a. Overview

UOP currently recommends three different methods for loading catalyst into CCR Platforming unit reactors. All three are acceptable regardless of unit design or reactor size. Differences in the quantity of fines generated from one method of loading to another are minimal. All fines that are generated from handling and loading will be removed from the system during the first two or three catalyst cycles. If the loading is done correctly, these fines will have no effect on the long-term operation of the unit.

A general description and a step-by-step description for each procedure is given below. At this point it is assumed that all of the reactors and internals have been assembled correctly, cleaned, and dried out (new units).

The selection of the catalyst loading method shall be done on site regarding the time schedule and the availability of the equipment required for each method.

b. Reactor by Reactor Loading Procedure (1) General Description

Of the three procedures, this has been the most common method used in the past. Drums of catalyst are hoisted up to the reactor manway area where a temporary loading hopper is situated. As catalyst is dumped into the hopper, it flows out the bottom through piping or conduit and enters the reactor through the reactor manway. At the end of the pipe or conduit is a loading sock which extends a few feet below the reactor coverdeck. From the other end of the sock the catalyst free fails to the bottom of the reactor. During the loading procedure, the sock is shifted to different areas of the catalyst bed annulus so the catalyst fills the reactor uniformly. If the catalyst falls in only one area, it will put an uneven stress on the centerpipe, and cause variations in the loading density.

Obviously, this frequent movement of the loading sock requires that a man be in the coverdeck area of the reactor throughout the loading. Dust protection is required. The loading hopper can be bolted to the manway but it is usually easier to locate it on a deck (permanent or temporary) above the manway. The layout of the piping and sock must be arranged so the catalyst flows freely. An angle greater than 35 degrees from horizontal should be acceptable. When

everything is running smoothly the loading crew should be capable of moving approximately 20 drums per hour or 2050 kg per hour.

A small variation to this approach can increase this loading rate significantly to over 60 drums per hour or 6150 kg per hour. It calls for loading the catalyst into large bins at grade and then lifting the bins up to the hopper. Typical bins used by catalyst handling companies hold approximately 1400 kg of catalyst. A separate crew at grade would be responsible for loading the catalyst into the bins, always staying ahead of the bin transfers.

Regardless of whether drums or bins are used, loading should always start in the lowest reactor and move up to the next highest when done. Loading in a reactor is complete when the catalyst level is approximately one foot below the open end of the catalyst transfer pipes. Short loading a reactor does not present a problem. However, if a reactor is overfilled, it will make it impossible to install the few coverdeck segments and catalyst transfer pipes not yet in place.

For reactors with a conventional regeneration section, the reduction zone can be loaded in a similar manner as the reactors by placing a catalyst loading funnel above the catalyst inlet flange on top of the reduction zone. Lift catalyst (drums or bins) and empty into the funnel. The reduction zone is full when the nuclear level instrument is satisfied. This is also a good time to verify that this nuclear level instrument works correctly. The side gas nozzle or the TI nozzle on top of the reduction zone is an excellent location to take an outage.

Measure, and document the size, shape and location of the catalyst hill as the nuclear level instrument comes on.

For reactors with a pressurized regeneration section, the reactor surge zone on top of reactor no. 1 can be inventoried the same way the reactors were; using a loading hopper, loading sock, and crane to lift the catalyst up to that elevation.

The output of the level instrument could be compared to a physical gauging of the zone to verify the accuracy of the level instrument. This zone should be filled to slightly more than the normal working volume to make up for slumpage during the initial startup.

On units where the top of the reduction zone (or reactor surge zone for pressurized regeneration sections) reactor no. 1 is too high for access or on new units or when extensive work was performed on the regenerated catalyst transport system, UOP recommends loading the top of reactor no. 1 and the reduction zone (or reactor surge zone) using the regenerated catalyst transport system. This procedure for loading using lift engager #2 is described in the Chapter 5 of the CCR Regeneration Operating Manual.

(2) Step-by-Step Description

After a final reactor inspection following unit dryout or turnaround, the reactors may be loaded by the following procedure:

a) Confirm that the manways on all reactors except the lowest reactor in the stack are closed to prevent a natural draft.

b) Establish dry instrument air purges to the reactor stack by connecting air hoses to the reactor outlet line pressure gauge connections or placing air hoses in the manway of the open reactor.

c) Remove two or three coverplate segments at equal spacing around the coverdeck in the lowest reactor in the stack.

d) Plumb bob each catalyst transfer pipe to insure it is unobstructed.

e) Place covers over top of each scallop riser prior to reactor loading. (Should be done as soon as the reactor manway is opened.)

f) Locate the catalyst loading hopper above the reactor manway. The deck above, temporary scaffolding or a special structure can be used to support the hopper. The loading hopper should be sized larger than the catalyst drums or bins.

g) Attach piping or flexible hose from the loading hopper outlet to the reactor manway.

h) Attach the loading sock to the piping or flexible hose; the sock should be long enough to extend at least two feet below the coverdeck level at each of the open coverplate locations.

i) If bins will be used to lift catalyst up to the reactor catalyst loading hopper, set up scaffolding and a catalyst addition hopper at grade to facilitate loading of the bins.

j) Start catalyst loading by lifting catalyst drums or bins up to the loading hopper located above the reactor manway.

NOTE: If the reactor catalyst disposal nozzles were not filled during the final reactor inspection with ceramic alumina balls as specified in the unit design specification, this should be completed prior to catalyst loading.

k) As catalyst is loaded to the reactor, move the loading sock to the different open coverplate locations; this will minimize the chance of loading at different densities at different points in the reactor bed. Raising the catalyst level evenly over the entire cross section of the reactor will also facilitate a constant density loading and reduce centerpipe stress.

l) Continue sock loading until the catalyst level is within a foot of the bottom of the catalyst transfer pipes.

m) For record purposes, measure the catalyst bed outage with respect to the bottom of the coverplate and note the total number of drums loaded.

n) Restore all coverplate segments along with their respective catalyst transfer piping. Carefully check transfer piping bolting for tightness and gaskets for gaps with a feeler gauge. A 0.13 mm blade is recommended.

o) Remove any debris or catalyst spillage from the coverplate area and remove the covers from the scallop risers.

p) Close reactor manway.

q) Proceed to load the other reactors in the same manner as described above, moving from lowest to successively higher reactors in the stack.

r) Load the top of reactor no. 1 and the reduction zone (or reactor surge zone for pressurized regeneration sections) via lift engager no. 2. See CCR Operating Manual.

s) After the stacked reactors are loaded, load the regeneration tower and disengaging hopper via the catalyst bins or drums. Load through the top flange or manway on the disengaging hopper until the nuclear level device indicates a level.

t) After catalyst loading is complete and the reactors are headed up, the reactor system should be evacuated and placed under a positive nitrogen pressure to await unit startup.

u) At the conclusion of the catalyst loading activities, the quantity of catalyst contained in each reactor should be determined. In addition, the loaded density should be computed based on measured reactor volumes.

c. Entire Reactor Stack Loading Procedure (1) General Description

This procedure calls for loading all the catalyst through the top of the reduction zone (or reactor surge zone for pressurized regeneration sections) on top of reactor no. 1. In many respects it is identical to the reactor by reactor loading procedure except there is only one loading point. This is the preferred procedure when the appropriate equipment is available to raise the catalyst to this height. Rates in excess of 80 drums per hour or 18200 kg per hour are possible when using large bins to lift the catalyst to the top of the structure.

Usually, a large hopper is centered over the catalyst inlet flange on the top of the zone head and a sock or sleeve joins the hopper to the catalyst inlet nozzle. Either butterfly or slide valve is located on the hopper outlet nozzle.

As the catalyst falls from the zone to reactor no. 1, to reactor no. 2 and so on, it spreads out in each reactor, filling the reactor uniformly. There is no problem with variations in loading density or uneven stresses on the centerpipe. It is felt that this method will produce marginally more fines than the previous procedure discussed but this should not pose a problem. As mentioned previously, the fines will be removed during the first two or three catalyst cycles.

(2) Step-by-Step Description

a) Use catalysts bins or drums to lift catalyst to the top of the reactor stack.

b) Load catalyst for all reactors through the catalyst inlet nozzle on top of the reduction zone (or reactor surge zone for pressurized regeneration sections).

c) Follow all the precautions and steps mentioned in the reactor by reactor loading procedure as they apply in this case.

NOTE: All manways must be covered to minimize a natural draft through the catalyst as it falls through each reactor.

d. Pneumatic Catalyst Loading Procedure (1) General Description

The pneumatic catalyst loading system consists of a stainless steel line running up the reactor structure similar to the regenerated catalyst lift line;

only larger in diameter. At grade this line is connected to a rotary valve unit which includes a rotary valve, catalyst hopper, and a dry air injection system. This pneumatic loading system is permanent and is ready to use at a moment's notice. With this system there is no need to plan ahead for a crane, hoist, temporary scaffolding, or equipment to be installed on the reactor structure.

Based on commercial experience to date the pneumatic system can load approximately 20 to 30 drums per hour or 2050 kg to 3070 kg per hour.

The system works as follows: Catalyst is loaded into the hopper above the rotary valve or wheel. As the rotary wheel turns, it moves catalyst from the hopper to the lift line pipe. Dry air injection into the bottom of the pipe pushes the catalyst up the pipe to the reactors at approximately 10.5 m/sec.

The rotary valve makes it possible to continuously take catalyst from atmospheric pressure up to approximately 1 kg/cm² g in the lift line. The lift line sections are connected by Dur-O-Lok* couplings. These easy-to-assemble/disassemble couplings are located so the lift line can be diverted into any one of the reactor manways and into the catalyst inlet line on top of the reduction zone.

This system has been used with various levels of success. It is very important that the rotary valve be as specified in the UOP Project Specification. If the valve is not constructed correctly, there could be excessive attrition, or there could be too much air leakage up through the valve into the catalyst hopper or shaft packing. Excessive air leakage will cause catalyst to be held up in the rotary valve inlet duct thus reducing the lifting rate. In two cases this problem was fixed by making a simple field modification. Both involved adding a small instrument air line into the rotary valve. In one case, a small instrument air line was added to the housing in the area after the rotary valve has picked up a load of catalyst and right after the vane has past the inlet duct. Pressuring up this compartment in the valve minimized the upward leakage rate and increased catalyst flow. Steps must be taken to protect the rotary valve housing from overpressuring. In the other case there was an air leakage problem. So, a small instrument air line was tapped into the rotary valve inlet duct and a differential pressure gauge was installed between the duct and the rotary valve catalyst outlet line. The air rate to the duct was adjusted to maintain an acceptable delta pressure and catalyst lift rate.

The lift line pressure is a function of how high the catalyst is to be lifted, air rate, catalyst transfer rate and the diameter of the lift pipe. However, this pressure should never exceed 1.4 kg/cm²g since this is the relief valve pressure at the base of the lift line. The relief valve is set to protect the rotary valve and to minimize backwards air flow.

*UOP, CCR Platforming are trade and/or service marks of UOP. Dur-O-Lok is a trademark of Dur-O-Lok.

If a refiner decides to use this loading option it is strongly recommended that the equipment be carefully inspected and run-in long before it is time to load catalyst. While running-in the equipment, check for maximum catalyst transfer rate and catalyst breakage as the catalyst exits the top of the lift pipe. If the rotary valve and lift line are properly fabricated, there should be no noticeable difference between the percentage of fines in the loading hopper and the lifted catalyst. For the run-in test, it is suggested that catalyst or catalyst base be lifted to the highest point and vented into a drum or hopper on the top deck. If using a hopper, a sock could be added to the hopper outlet back down the structure to the rotary valve hopper; making a closed loop.

The rotary valve specified by UOP is set at a fixed rpm. Some refiners have made it adjustable (changeout gears) to increase the lifting rate without increasing the apparent quantity of fines produced.

(2) Step-by-Step Procedure

See the UOP Project Specification and Drawings, if applicable.

6.3 ATTACHED DOCUMENTS FOR CATALYST LOADING

The following documents show the catalyst quantity as well as the reactors R-1301 thru 1304 layout :

♦ UOP Project Specification 903369-105-sheet 1 : quantity of catalyst,

♦ UOP Project Specification for Ceramic/Alumina Balls (903369-312),

♦ Data sheet of Reactors R-1301 thru 04 : 8474L-013-PDS-R-1301-001.

CHAPTER 6