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PROCEDURE
CECA ADSORBENTS FOR THE OIL AND GAS INDUSTRY
HANDLING
PROCEDURES
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CECA Adsorbents Handling Procedures
CONTENT :
INTRODUCTION
BASICS OF ADSORPTION
STORAGE INSTRUCTIONS
HANDLING INSTRUCTIONS
VESSEL LOADING INSTRUCTIONS
VESSEL UNLOADING INSTRUCTIONS
DISPOSAL OF CECA ADSORBENTS
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CECA Adsorbents Handling Procedures
INTRODUCTION
This document details CECA requirements for the
handling of adsorbents (molecular sieves, activated
alumina, silica gel) and ceramic balls in process units.
All the information and recommendations enclosedshould be well understood in order to optimize the
loading, unloading and disposal operations, and to
perform them safely.
This document is for the sole internal use of CECA
adsorbents customers. It is confidential and not to bedisclosed to any third party without CECA explicit
consent in writing.
Do not hesitate to contact us for any question you
may have :
CECA S.A., Molecular Sieve Department
Dynamic Applications
Tel : +33 1 49 00 38 19
Fax : +33 1 49 00 38 03Email : [email protected]
BASICS OF ADSORPTION
In gas and liquid separation applications, the aim is
to selectively retain molecules that form low energy
bonds with the adsorbent internal structure. This
phenomenon is called physisorption and follows
adsorption isotherms. It is exothermic (it releasesenergy in the form of heat).
To be efficiently adsorbed, the polar molecules must
be small enough to enter the cavities of the adsorbent
via their pores. The diameter (or the size distribution)
of the pores and cavities depend on the type ofadsorbent, which is therefore chosen depending on
the application and the molecules to be separated.
Typical adsorbents are available in the form of 0.5 to
5.0 mm beads or pellets. They are loaded in vessels
and used as fixed bed.
The impurities in the treated stream saturate the
adsorbent bed generally within a few hours or days.
By changing the adsorption equilibrium conditions
(lower pressure, higher temperature or both), the
adsorbed molecules can be desorbed from the active
sites, and the adsorbent can recover most of itsoriginal adsorption capacity: it is “regenerated”.
Introduction
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CECA Adsorbents Handling Procedures
STORAGE INSTRUCTIONS
CECA adsorbents are shipped in air-tight, non
returnable steel drums or semi-bulk bags (called “big
bags” in the following). See our Standard Offer for
Packing, Marking and Expedition for details.
In all cases we recommend to warehouse the pallets
indoor in order to prevent them from bad weather
conditions (rain, sand storm, etc.), direct sun and
ground humidity.
Outside storage is not recommended, in particular forbig bags. Should indoor storage not be feasible, the
drums or big bags pallets would have to be protected
by waterproof tarps and be isolated from the ground.
In the case of big bags, outside storage has to be
limited, in all cases, to short periods (for instance
just before loading the vessels).
The drums can be stored up to 5 years under cover.
Big bags cannot be stored for more than 2 years, even
under cover. For longer storage durations, we
recommend to sample and analyse the products, in
order to make sure they are still fit for use.
These recommendations are general and may slightly
differ depending on the product type, packaging,
storage location, etc. In any case, ask CECA to make
sure your storage conditions meet our requirements.
HANDLING INSTRUCTIONS
Before handling CECA adsorbents, read the
corresponding Material Safety Data Sheet (MSDS)
for the up-to-date safety, handling and regulatory
information.
CECA adsorbents are silica gels, aluminas or
alumino-silicates (zeolite-based molecular sieves).
They are chemically similar to ordinary clays and are
therefore inert under normal handling conditions.
They exhibit no vapour pressure and have no
flammable constituents.
The main potential serious hazard is related to non
(or poorly) regenerated adsorbents desorbing
hazardous species (H2S, etc.) after unloading of the
vessels. This scenario and how to avoid it is
described in CECA Unloading Procedure.
CECA adsorbents are extremely powerful desiccants.
They remove water from any substance they come in
contact with. As adsorption is exothermic, it can
cause burns to a sweating skin. Gloves must be worn
while handling CECA adsorbents. No adsorbent dust
must be inhaled or allowed to come in contact witheyes. The use of dust mask, goggles, and Breathing
Apparatus systems, if in confined space, are
mandatory. Excessive or severe handling can cause
some dusting.
Do not hesitate to contact us for any question you
may have :
CECA S.A., Molecular Sieve Department
Dynamic Applications
Tel : +33 1 49 00 38 19
Fax : +33 1 49 00 38 03Email : [email protected]
The statements, technical information and recommendations contained herein are believed to be accurate as of the date hereof. Since
the conditions and methods of use of the product and of the information referred to herein are beyond our control, ARKEMA expressly
disclaims any and all liability as to any results obtained or arising from any use of the product or reliance on such information; NO
WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE, WARRANTY OF MERCHANTABILITY OR ANY OTHER WARRANTY, EXPRESS
OR IMPLIED, IS MADE CONCERNING THE GOODS DESCRIBED OR THE INFORMATION PROVIDED HEREIN. The information provided
herein relates only to the specific product designated and may not be applicable when such product is used in combination with other
materials or in any process. The user should thoroughly test any application before commercialization. Nothing contained herein
constitutes a license to practice under any patent and it should not be construed as an inducement to infringe any patent and the user
is advised to take appropriate steps to be sure that any proposed use of the product will not result in patent infringement. See MSDS for
Health & Safety Consideration
CECA
89, boulevard National
92257 La Garenne-Colombes Cedex - France
cecachemicals.comStorage & Handling 1/1
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CECA Adsorbents Handling Procedures
VESSEL LOADING INSTRUCTIONS
These instructions detail the standard loading method.
Special methods such as dense loading or pneumatic
loading are not discussed here.
1/ REQUESTED EQUIPMENT
1.1/ Area
Enough space is needed around the vessels to store
the drums or big bags. As a reminder, ground surface
for 1 pallet (4 drums or 1 big bag) is about 1m2.
Moreover, some space is necessary for the loadingprocess : filling the hopper, crane and forklift
manoeuvres, etc.
1.2/ Hopper and loading system
Except for the bottom ceramic balls (see § 5.3/below),
the products are usually loaded via a hopper.
In the case of drums, it is recommended to first pour a
few drums in the hopper, and to lift the hopper with a
crane (the hopper must be equipped with lifting
hooks).
Loading drums one by one is not recommended as
the quantities involved are important. Big bags can
also be first poured in a hopper, or they can
alternatively be lifted directly. See Figures 1 and
Figure 2 below.
When a hopper is used, its capacity and resistance
must comply with the requested use (1 pallet = 4 to 5drums = 500 to 700 kg) or 1 big bag (800 to 1000 kg).
The bottom opening must be large enough to preventclogging. A diameter of 150 mm is a minimum (300
mm is recommended).
The hopper valve must be easy to operate and must be
able, if needed, to quickly stop the product without
crushing the beads or pellets. A guillotine valve isusually the best compromise. When big bags are used
and directly lifted, their bottom short sleeve must be
opened with care and the flow of product must also be
controlled.
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CECA Adsorbents Handling Procedures
Attached to the bottom of the hopper, or to a cone-
shaped system fixed to the manhole (in particular
when big bags are lifted), a long sleeve prevents the
adsorbents from falling from too high. It is a flexible
cylinder-shape piece, which diameter is at least equalto the diameter of the bottom opening of the hopper or
cone-shaped system.
The sleeve can be made from various flexible,
resistant materials, such as any cloth, plastic films,flexible pipes, constructions conducts, etc. Its length
is reduced from time to time, in order to always havebetween 600 and 1000 mm from the bottom of the
sleeve to the top of the bed. The sleeve must also be
equipped with a rope attached to its end. This rope is
used to direct the product flow inside the vessel.
Example of an equipped hopper
1.3/ Crane
A crane is required to lift the filled hopper (or the big
bags) from the ground up to the vessel manway.
1.4/ Forklifts
Forklifts are used to carry the drum or big bag pallets.Two forklifts is a minimum : one to bring full drums
from the storage area to the hopper filling area, andanother to bring empty drums on pallets to another
storage area.
1.5/ Hopper filling area / Scaffolding platform
When drums have to be loaded in a hopper, a securedplatform is convenient to handle the pallets and to fill
the hoppers securely (see § 4.6 for details).
Note: The platform can be replaced by a hole made in
the ground, in which the hopper is loaded. In this casedrums are simply rocked on the hopper.
sleeve
rope
valve
Cone-bottomshaped hopper
pouredproducts
Figure 1
sleeve
rope
valve
Cone-bottomshaped hopper
pouredproducts
Figure 1
liftedbig bag
sleeve
rope
Figure 2
liftedbig bag
sleeve
rope
Figure 2
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CECA Adsorbents Handling Procedures
1.6/ Safety equipments
Safety / PPE (Personal Protective Equipment) outfits
and fittings have to be available and used accordingto the plant’s safety rules. Contact CECA in caseyou have any question or any doubt. Equipment
typically includes :
Helmet, gloves, safety shoes, dust mask, harness,
goggles, clothes with long sleeves, Breathing
Apparatus systems, portable oxygen detector.
1.7/ Wood boards and ladder
A ladder (long enough to go from the top manway
down to the support grid) is necessary. At least 3
wood boards are needed in order to put up the ladderand walk on the bed during the levelling steps.
Note : a winch can also be used instead of a ladder.
1.8/ Rake
A rake (or a “rake-type” tool) is needed for bed
levelling operations.
1.9/ Rulers
Rulers are useful to measure the level of product in
the vessel from time to time, and therefore controlits homogeneity all around the vessel after a
levelling operation. Rulers have to be long enough.
If they cannot be easily provided, they can be
replaced by scaled ropes or by tape-measures.
Note : an alternate solution is to graduate the vessel
wall in several locations on its circumference and all
along its height while the vessel is empty (for
example using a chalk).
1.10/ Stainless yarn
Stainless yarn is used when wire mesh screens aresupplied in several pieces that have to be partially
overlapped and tied together (usually for large vesseldiameters).
Note : blind rivets can also be used.
1.11/ Spare screens
For each kind of wire mesh screen in the vessel, it is
necessary to have spares (and / or spare parts). This
is true essentially for change outs, in order to be able
to immediately replace former screens if damaged,
or at least to repair them.
1.12/ Tarpaulin - Plastic cover
If sudden rain or snow occurs during the loading
operation, it is important to be equipped to protect theproduct from exposure (hopper and vessels). For eachvessel, at least one plastic cover, to be put on the
manhole, is requested. Tape is needed to fix it tightly.
1.13/ Lighting equipment
Lights (flashlights, spotlights) are needed to see insideand inspect the vessels.
1.14/ Other useful tools
Cutters, scissors, adhesive tape, etc.
2/ UTILITIES
No specific utilities are required to perform CECA
adsorbents loading. However, a source of inert dry
gas (typically nitrogen) is highly desirable in order to
purge and remove atmospheric air from the bed after
loading.
3/ MANPOWER
In order to proceed securely, we highly recommend tohave at least 7 workers per team. We also suggest the
following dispatch :
Crane : 1
Forklifts : 2
Hopper filling / big bag preparation : 2
Filling operation / levelling / supervision : 2
The number of needed teams depends on the loading
conditions (day shift, 24hr/day, several vessels loaded
at the same time, etc.)
Loading supervision can sometimes, upon request andcommercial agreement, involve a CECA
representative. In that case, the CECA representativeis only responsible for indicating what has to be done
and what has to be avoided. He / She has no
hierarchical link with the loading team, and it is
essential that he / she directly reports to a company
official loading supervisor who organizes the work in
practice.
CECA representative can, at any time, instruct to
stop the loading operation, upon circumstances
which to his judgment, could result in unsafe or
improper performance.
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4/ PRELIMINARY OPERATIONS & SPECIAL
RECOMMENDATIONS
4.1/ Typical vessel layout
See Figure 3 for a typical vessel layout (may slightly
differ from a unit to another)
In some cases, a V-wire grid type (by “Johnson
Screens” and others) is used instead of the support
grid and bottom wire mesh screens.
4.2/ Wire mesh screens
The wire mesh screens that are installed over the
grid and / or below the top ceramic balls must be
new or damage free. For large vessel diameters, theyare usually supplied in several pieces that need to be
partially overlapped (5-10cm) and well tied together
with the use of stainless yarn, wire or blind rivets.
4.3/ Grid – wall sealing
Due to thermal expansion (especially in the case of a
TSA - Temperature Swing Adsorption system), thesupport grid and the vessel show a little gap. In orderto prevent any product leakage, it is paramount to
ensure a perfect sealing between the grid and the
vessel wall. This is usually done with several layers
of ceramic rope inserted in the gap.
Ceramic rope sealing
Figure 3
Loading 4/7
Ceramic balls layers
Ceramic balls layers
Ceramic balls 1”
Alumina or Silica gel guard bed layer
(when applicable)
Molecular sieves layers
Fiber rope around the
whole circumference
(gasket / tightness)
Manhole /
dump port
Baffleplate
with 4
holes
Inlet nozzle with rectangular slots
showing suitable open area, and
covered with 20 mesh screen*.
Bottom of distributor
Top of products
600 mm
mini.
20 mesh screen*
(+ 15 cm overlap)
10 mesh screen*
3 mesh screen*
Main support grid
I-beam supports 20 mesh screen*
* US size N° 20, 10 and 3 Stainless Steel Mesh Screen
Floating screen
Optional and strongly recommended : Hold-down ring
all around the vessel circumference, to reliably maintain
the bottom screens and ensure a suitable tightness
Ceramic balls layers
Ceramic balls layers
Ceramic balls 1”
Alumina or Silica gel guard bed layer
(when applicable)
Molecular sieves layers
Fiber rope around the
whole circumference
(gasket / tightness)
Manhole /
dump port
Manhole /
dump port
Baffleplate
with 4
holes
Inlet nozzle with rectangular slots
showing suitable open area, and
covered with 20 mesh screen*.
Bottom of distributor
Top of products
600 mm
mini.
20 mesh screen*
(+ 15 cm overlap)
10 mesh screen*
3 mesh screen*
Main support grid
I-beam supports
20 mesh screen*
(+ 15 cm overlap)
10 mesh screen*
3 mesh screen*
Main support grid
I-beam supports 20 mesh screen*20 mesh screen*
* US size N° 20, 10 and 3 Stainless Steel Mesh Screen
Floating screen
Optional and strongly recommended : Hold-down ring
all around the vessel circumference, to reliably maintain
the bottom screens and ensure a suitable tightness
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In addition to that, the upper 20 mesh screen overthe grid must be larger than the vessel diameter in
order to provide a 10-15 cm overlap up the wall. A
hold-down ring that maintains the mesh screen is
recommended.
Mesh screen with overlap and a hold-down ring
4.4/ Clean and dry vessel
Before the loading starts, the vessel and all internals
must be perfectly clean and dry (air movers or dry
gas blowers may have to be used). It is extremely
important to make sure there is no remaining dead
volume of water.
4.5/ Side manhole blind
The side manhole can sometimes represent a
significant volume. It is recommended to insert a
blind with a few tiny hole for pressure equalization.(The holes must be small enough to prevent beads or
pellets to go through.) See Figure 4.
Figure 4
4.6/ Management of drums and big bags
It is very important to foresee and organize the
transfer of the drums and big bags from their mainstorage to the loading operation area. Removal /
disposal of empty packaging has to be planned aswell, in order not to clutter the loading area.
The quantity of big bags and / or drums
corresponding to a given vessel load must be stored in
a dedicated area near it. They must be arranged in theorder of loading.
When loading a hopper with drums using a platform,
bring the pallet on the platform with a forklift. Drums
are brought one by one to the tilting area of the
scaffolding. They are opened and poured into the
hopper. Empty drums are brought back on the pallet,and the pallet with empty drums is brought to the
specific storage area by the second forklift.
Example of a platform
4.7/ Prevention from humidity or air
In order to prevent adsorption of atmospheric water
on the adsorbents, it is important not to open the
drums before being ready to pour the product into the
hopper.
Several minutes of exposure during loading does not
cause significant water pick up.
During the night, manholes have to be hermeticallyclosed. If possible, it is recommended to flow dry air
or nitrogen into the vessels.
5/ LOADING OPERATION
The following procedure is made of standard
suggestions and advice that must be adapted to each
case. The operation must always conform with site
safety rules. We consequently ask you to read this
procedure carefully, and to contact us if any questionarises.
Loading 5/7
Ceramic balls
Grid and screens
Ceramic balls
Grid and screens
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5.1/ Hopper / big bag lifting
The hopper (or the big bag) filled with products is
lifted by the crane up to the top level of the vessel;
right above the manhole.
Hopper and big bag lifting Here a second hopper with a long sleeve is already
installed on the vessel manhole
5.2/ Adsorbents loading
The product is carefully released by slowly openingthe hopper valve (or the bottom of the big bag), and
flows into the sleeve. The flow must be controlled
(in order to prevent clogging of the sleeve) and
directed (thanks to the rope, in order to well spread
the products and avoid a too large slope).
When the hopper is empty, it is brought back to the
ground level for the next operation.
It is highly recommended to prepare andcontinuously fill out “loading sheets” with the lot
numbers, timing, product height (see § 5.4), etc.
5.3/ Ceramic balls loading
It is possible to load the bottom ceramic balls from
the top, like the adsorbents. However, as they are
bigger (typically up to 1/2 inch diameter) and denser,
the flow must be very well controlled in order to
avoid damaging the balls and the bottom mesh
screens.
When it is possible, bottom ceramic balls arepreferably loaded using a rope and buckets (or
directly through the side manhole when there is one).
It is necessary to first put the ceramic balls all aroundthe circumference of the vessel, in order to well
maintain the mesh screens and ensure a good seal
thanks to the 20 mesh screen overlap.
Top ceramic balls can also be loaded with buckets.
Ceramic balls lying on the mesh screen
5.4/ Bed levelling
Bed levelling is a crucial operation that needs to be
performed regularly and neatly in order to have
homogeneous layers of products.
The number of levelling operations is a function of
the number of loaded grades, height of the layers,
vessel diameter, etc. As a minimum, it has to be done
for each layer of products; but is usually alsoperformed at intermediate levels.
The person in charge, who enters the vessel must
wear all the required safety equipments (see § 1.6).
He / She has to stand on wood boards and levels the
bed using a rake or a rake-like tool.
After the bed is considered flat and well levelled, the
height between the top of the bed and the manhole is
measured and compared to the forecasted one.
5.5/ Top 20 mesh screen
The 20 mesh screen with overlap is installed on top of
the adsorbents (below the top ceramic balls, seeFigure 3). It is important not to tie this mesh screen
with the vessel.
If any internal such as a purge pipe (or a feed pipe or
temperature probes) has to go through the 20 mesh
screen, it is requested to make a hole of the samediameter in the screen, and to surround the internal
with a cone-shaped piece of 20 mesh screen. This
piece must be attached to the 20 mesh screen, but not
to the internal. It is recommended to do this work
once the screen is in the vessel.
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Operators equipped for internal operation
5.6/ Waiting for start-up
After the loading and before the start-up, the oxygen
must be removed from the vessel, typically by a
nitrogen purge. Often the available flow-rate of
nitrogen is too low to provide the required turbulentflow. The vessel has to be pressurized and
depressurized several times with nitrogen
(preferably downstream in order not to lift the bed) –
contact CECA if this is not feasible.
If the unit is loaded and not to be put in service
before several weeks or months, it is recommended
to isolate the vessel from the rest of the process. This
will prevent trace contaminants and moisture from
being introduced into it. If the above procedures are
followed, it is not be necessary to regenerate the
beds prior to start-up. Here also a small nitrogen
pressurization can help ensure no outside moisturewould come in.
Do not hesitate to contact us for any question
you may have :
CECA S.A., Molecular Sieve Department
Dynamic Applications
Tel : +33 1 49 00 38 19
Fax : +33 1 49 00 38 03Email : [email protected]
The statements, technical information and recommendations contained herein are believed to be accurate as of the date hereof. Since
the conditions and methods of use of the product and of the information referred to herein are beyond our control, ARKEMA expressly
disclaims any and all liability as to any results obtained or arising from any use of the product or reliance on such information; NO
WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE, WARRANTY OF MERCHANTABILITY OR ANY OTHER WARRANTY, EXPRESS
OR IMPLIED, IS MADE CONCERNING THE GOODS DESCRIBED OR THE INFORMATION PROVIDED HEREIN. The information provided
herein relates only to the specific product designated and may not be applicable when such product is used in combination with other
materials or in any process. The user should thoroughly test any application before commercialization. Nothing contained herein
constitutes a license to practice under any patent and it should not be construed as an inducement to infringe any patent and the user is
advised to take appropriate steps to be sure that any proposed use of the product will not result in patent infringement.
See MSDS for Health & Safety Consideration
CECA
89, boulevard National
92257 La Garenne-Colombes Cedex - France
cecachemicals.com Loading 7/7
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VESSEL UNLOADING INSTRUCTIONS
1/ SAFETY
Unloading adsorbents from a process vessel requires
a good knowledge of the application and a thoroughunderstanding of the possible hazards. Most of the
time, toxic and/or explosive substances are present
in the vessel at the end of the process operation
(including after the last regeneration). This can be
the regeneration medium itself (fuel gas, etc.), heavy
hydrocarbon deposit (coke), or toxic adsorbed
molecules (H2S, etc.) in some applications, when the
last regeneration is not complete or not
homogeneous. In any case safety requires absolute
caution.
1.1/ Safety equipments and concerns
Safety / PPE (Personal Protective Equipment) outfits
and fittings have to be available and used accordingto the plant’s safety rules. Contact CECA in case
you have any question or any doubt. Equipment
typically includes :
Helmet, gloves, security shoes, dust mask, harness,
goggles, clothes with long sleeves, BreathingApparatus systems, portable oxygen detector.
Before any entry in the vessel, the inside has to be
checked with an appropriate device to be lower than
20% of the Lower Explosive Limit (LEL).
Grounding of all equipments is recommended,
including trucks (for vacuum unloading). However,static sparks may still occur because of non-
conducting containers or other materials.
CECA adsorbents are silica gels, aluminas or
alumino-silicates (zeolite-based molecular sieves),
chemically similar to ordinary clays. As fresh
materials they are chemically inert under normal
handling conditions, exhibit no vapour pressure and
have no flammable constituents. However, used
adsorbents have been exposed to liquid or gaseous
materials containing traces of other products, such as
saturated and unsaturated hydrocarbons, coke or
sulphur compounds. These products may be toxic,flammable or explosive. When exposed to air or rain,
they may heat up or be released in the atmosphere.
It may happen that during unloading, the adsorbents
start to burn. In this case, all operation must be
stopped immediately by trained and equipped fire-
fighters.
Note : This is the only case which allows to spray
water on (non vessel flooded) unloaded adsorbents.
Spraying water on dry adsorbents can release all the
other adsorbed molecules, potentially toxic, that
would remain in the material.
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1.2/ Last Regeneration
Before being unloaded, the adsorbents must be
properly and completely regenerated in order to
remove as much adsorbed compounds and depositsas possible. Use the same regeneration procedure asusual, unless you have clues or evidence that it is not
reliable enough to desorb all impurities. In this case,
or if the usual regeneration gas is not available,
contact CECA.
1.3/ Purge and deactivation
After the last regeneration, adsorbent beds have to
undergo a special treatment to remove the last traces
of impurities still present. One of two treatments are
usually implemented : nitrogen purge or water
flooding. It is not always possible to choose betweenthe two as this is subject to constraints (nitrogen
availability, type of insulation, etc.) Furthermore, it
is important to understand that these 2 methods are
not equivalent (they do not act the same way) :
- Nitrogen purge removes the process fluid that is
still in the vessel, but does not desorb the molecules
still in the pores. It is a vessel purge only,
preferentially used for the cleaner applications
(natural gas drying, etc.) that do not involve too
reactive or toxic substances.
- Water flooding removes the process fluid but alsocompletely desorbs each and every adsorbed
molecule (which are displaced by water molecules).
This is an adsorbent deactivation process that is
preferentially used in case of reactive / toxic streams
involving hazardous adsorbates. In case of poor
regeneration (too low flow-rate, channelling issues,
etc.), some hazardous molecules (such as H2S and
others) can stay in the adsorbents porosity. If the
material is directly unloaded and then exposed to air
and / or moisture, it can burn or be released, leading
to dangerous situations.
Nitrogen purge :
This method is the most common, and is generallyfaster than water flooding as it is not required to dry
the unit afterwards. Its main drawback is the use of
large quantities of nitrogen, which is sent to the flare.
After the last regeneration cooling step, totally
isolate the vessel, and depressurize down toatmospheric pressure. Install blind flanges on every
pipe, except to the flare and on a sample tap at the
bottom of the vessel, which has to be connected to
the nitrogen network. Start the purge by flowing
nitrogen through the bed and direct the outlet to theflare. The nitrogen flow-rate must be sufficient to
avoid channelling. Minimum flow-rate and durationof the purge can be estimated by your CECA
representative. It must be maintained until the gas
going to the flare reaches 20% of the Lower
Explosive Limit (LEL). Measurement is usuallydone at a tap on the flare line, using an appropriateanalyser.
If the nitrogen availability is too low to provide the
requested flow-rate, the alternate solution is to
perform this purge by successive pressurizations and
depressurizations of the vessel. In that case the flareline is closed, and only the nitrogen valve is opened.
Gas fills the vessel till the pressure stabilizes at
network pressure. The valve is then closed and the
flare line is opened, so that the vessel depressurises
through it. Once the pressure is stabilized, the flare
line is closed again and a new cycle starts. Usually 3to 5 pres. / depress. steps are required to obtain less
than 20% LEL.
Water flooding :
Water flooding is used when nitrogen is not
available, or when there is a risk that hazardous
substances are still imprisoned in the adsorbents’
porosity.
Note : water flooding cannot be used in case of
internal insulation (as it would damage the casting).
Vacuum unloading can also be difficult to proceed,especially if a lot of fines is present.
After the last regeneration cooling step, totally
isolate the vessel, and depressurize down to
atmospheric pressure. Install blind flanges on every
pipe, except to the flare and on a sample tap at the
bottom of the vessel, which has to be connected to
the water network. Slowly fill the vessel with water.
A fast temperature increase will be observed as the
water comes into contact with the regenerated
adsorbents. This is a normal non hazardous
phenomenon which can be somehow controlled by
the vessel filling rate. Fill the vessel until theadsorbents and the ceramic ball layers are totally
flooded by water, but be careful not to overfill andflood the flare line (the water height can be
estimated from a flow-meter and / or a differential
pressure gauge). Plug a flexible pipe to the tap and
send all the water to the waste water treatment
station. In the vessel, adsorbents and ceramic balls
are soaked, and ready for unloading.
Note : For special cases involving hazardous
substances, that cannot be water flooded, the
regenerated adsorbents have to be unloaded into
special metal containers with a bottom tap connectedto water and a top tap connected to a vent line and to
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CECA Adsorbents Handling Procedures
the flare. A water flooding process can therefore beimplemented outside of the vessel for each container.
2/ UNLOADING
All internals must be removed from the adsorbent
bed (temperature probes, sampling devices, etc.)
After having performed the operations described at
chapter 1.2/ and 1.3/, the vessel can be opened and
the unloading can start.
Top 1” ceramic balls and mesh screen must be first
removed by the top manway (See chapter 1.1 for
safety equipment). Sometimes 1” ceramic balls and
mesh screen are not removed and go down in the
vessel as adsorbents are unloaded by through sidemanway. In this case, a hook-type device should be
used to retain the top screen prior to unloading the
bed, in order to prevent it is pulled down and block
the outlet.
Used material can be removed either by pneumatic
unloading (vacuum unloading), or by gravity
unloading.
Pneumatic unloading :
If a pneumatic truck is chosen, the adsorbents must
be dry. A flexible pipe is put into the vessels andsucks the products under vacuum. Most of the time
it is necessary that one person remains in the vessel
to direct the flexible pipe. Used adsorbents are then
sent to a bin or to empty big bags. The used material
is often broken and partially reduced to fines when
going through the suction system.
Grounding of the truck is required. This method is
the fastest and the easiest one.
Gravity unloading :
If gravity unloading is chosen, the bottom side
manway (or the dump port) is carefully opened to let
the product flow. A special cone-shaped piece ofmetal or wood is put below the manway to direct theflow into the bin or big bags. The flow is controlled
by adjusting the manway opening. The product flow
is important at the beginning, and slowly decreases.
After some time, no more material goes out of the
vessel, and it is necessary to complete the unloading
manually, using rakes.
When all the used adsorbents are out of the vessel,
the bottom ceramic balls are unloaded manually. If
they are to be re- used, the different sizes can be
separated by sieving.
When the bottom ceramic balls are unloaded, check
the bottom support grid and the mesh screens (or the
V-wire screen) to make sure they can be reused or
need to be repaired or changed.
Before reloading of fresh adsorbents, carefully and
thoroughly dry the vessels, piping and internals,
(including the ceramic balls). Fresh material should
avoid any contact with remaining moisture
Do not hesitate to contact us for any question
you may have :
CECA S.A., Molecular Sieve Department
Dynamic Applications
Tel : +33 1 49 00 38 19
Fax : +33 1 49 00 38 03
Email : [email protected]
The statements, technical information and recommendations contained herein are believed to be accurate as of the date hereof. Since
the conditions and methods of use of the product and of the information referred to herein are beyond our control, ARKEMA expressly
disclaims any and all liability as to any results obtained or arising from any use of the product or reliance on such information; NO
WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE, WARRANTY OF MERCHANTABILITY OR ANY OTHER WARRANTY, EXPRESS
OR IMPLIED, IS MADE CONCERNING THE GOODS DESCRIBED OR THE INFORMATION PROVIDED HEREIN. The information provided
herein relates only to the specific product designated and may not be applicable when such product is used in combination with other
materials or in any process. The user should thoroughly test any application before commercialization. Nothing contained herein
constitutes a license to practice under any patent and it should not be construed as an inducement to infringe any patent and the user
is advised to take appropriate steps to be sure that any proposed use of the product will not result in patent infringement. See MSDS for
Health & Safety Consideration
CECA
89, boulevard National
92257 La Garenne-Colombes Cedex - France
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CECA Adsorbents Handling Procedures
DISPOSAL OF WASTE ADSORBENTS
Before dumping used adsorbents, please consult thecorresponding MSDS. If you don’t have it, please
ask your CECA representative to send you a copy.
Unloaded adsorbents may retain toxic or flammable
components. Do not directly flood adsorbents with
water, and keep them in bin or big bags until they
leave the plant.
Depending on local environmental regulations,
adsorbents may or may not be disposed in a
controlled landfill. Landfill is the final destination of
used adsorbents in most cases. Preliminary analysis
of adsorbents are requested to determine the type ofappropriate landfill.
If the adsorbents cannot be spread on an open field,
it is then necessary to dead burn them in cement
factory ovens, and to further use them as raw
material for the cement industries. This is especially
true for very large quantities of used material.
Adsorbents residual hydrocarbon content shall be in
any case less than 0.5% by weight.
Please note that a large number of specialised
companies propose to handle used adsorbents. These
companies know local regulations and take care ofall required testing and administrative declarations.
They are usually the same companies handling the
other waste chemicals produced in the plant.
Do not hesitate to contact us for any question
you may have :
CECA S.A., Molecular Sieve Department
Dynamic ApplicationsTel : +33 1 49 00 38 19
Fax : +33 1 49 00 38 03
Email : [email protected]
The statements, technical information and recommendations contained herein are believed to be accurate as of the date hereof. Since
the conditions and methods of use of the product and of the information referred to herein are beyond our control, ARKEMA expressly
disclaims any and all liability as to any results obtained or arising from any use of the product or reliance on such information; NO
WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE, WARRANTY OF MERCHANTABILITY OR ANY OTHER WARRANTY, EXPRESS
OR IMPLIED, IS MADE CONCERNING THE GOODS DESCRIBED OR THE INFORMATION PROVIDED HEREIN. The information provided
herein relates only to the specific product designated and may not be applicable when such product is used in combination with other
materials or in any process. The user should thoroughly test any application before commercialization. Nothing contained herein
constitutes a license to practice under any patent and it should not be construed as an inducement to infringe any patent and the user
is advised to take appropriate steps to be sure that any proposed use of the product will not result in patent infringement. See MSDS for
Health & Safety Consideration
CECA
89, boulevard National