This article is about Sieve Loading Procedure used in refinery and plants. Here you will find answers of How long do molecular sieves last, What is molecular sieve theory?, molecular sieve types and What is water adsorption capacity of molecular sieve.
Sieve Loading Procedure
Loading is done by the Vendor Specialist like AXENS Catapac specialist according to the AXENS Sieve Loading Procedure.
a. Prerequisites
✓ Sieve is available.
✓ Tray installation is achieved and is satisfactorily checked and cleaned.
✓ Next tray beams are installed.
✓ Center Pipe ladder and all material have been removed.
✓ Crane and all equipment involved in the bed loading is suitable for operating the CATAPAC apparatus at 10 to 15 tons of sieve per hour.
✓ Power dry air for CATAPAC available.
Important Note: For proper sieve loading, it is mandatory to avoid any disruption of the machine during this phase (unless the CATAPAC is stopped by AXENS dense loader for sieve level checking).
b. Sieve Loading
✓ Prior loading, bags are weighted and store inside the bags temporary shelter.
✓ Main steps of sieve loading operation.
✓ Measure the bed depths and the shell radius on some points following a specific procedure issued by AXENS. These measures will be used to check the loading density per bed.
• Check the big bags at ground. ( coarse sieve and fine sieve)
• Check the loading device on top.
• Install the Catapac.
• Load the coarse sieve.
• Stop the Catapac and check the levelling of sieve.
• Load the fine sieve.
✓ Stop the Catapac and check the loading. These operations could be done several times during loading.
• Adjust the Catapac if necessary.
• Carry on the loading up to the top of beams.
• Level the sieve with sieve scrappers.
c. Sampling
✓ 50 plastic bottles of 1.0 liters to be available for sampling purpose. These bottles cover shall be of the seal tight type.
✓ Bottles should be labelled with the adsorber identifying suffix (A or B), the bed number and small letter a or b to distinguish the first sample from the second.
✓ Bottle a, is immediately send to the client laboratory to perform Loss Of Ignition (LOI). LOI to be performed within less than 4 hours after the relevant bed had been loaded. This specific lab activity measurement has to be clearly scheduled in the lab organization.
✓ Bottle b, is kept under dry air and completely sealed for potential cross checking analyses.
✓ After LOI measurement, the samples are stored and kept as reference for any analyses which might be necessary later on.
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FAQs about Sieve Loading
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How long do molecular sieves last?
The lifespan of molecular sieves can vary depending on various factors such as the specific application, operating conditions, and the type and quality of the sieves. Generally, molecular sieves have a long lifespan and can last for several years under normal operating conditions. However, their efficiency and performance may gradually decrease over time, requiring replacement. Regular monitoring, maintenance, and regeneration processes can help extend the lifespan of molecular sieves. It is important to follow manufacturer guidelines and conduct routine inspections to ensure optimal performance and determine when replacement is necessary.
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What is molecular sieve theory?
Molecular sieve theory is based on the principle of selective adsorption and separation of molecules based on their size and shape. Molecular sieves are porous materials with uniform pore sizes that allow the adsorption of certain molecules while excluding others. The theory behind molecular sieves involves the concept of size exclusion, where molecules smaller than the pore size can enter and be adsorbed, while larger molecules are effectively excluded.
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What are molecular sieve types?
Molecular sieves are classified into various types, including zeolite molecular sieves, silica gel, activated carbon, aluminophosphates (ALPOs), and metal-organic frameworks (MOFs). Zeolite molecular sieves have uniform microporous structures and different pore sizes, while silica gel is commonly used as a desiccant. Activated carbon has a large surface area and is effective at adsorbing organic compounds. ALPOs have diverse pore structures and properties, and MOFs are crystalline materials with high porosity and selectivity. Each type of molecular sieve is used for specific applications based on their unique properties.
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What is water adsorption capacity of molecular sieve?
The water adsorption capacity of molecular sieves varies depending on the type and pore size of the sieve. Zeolite molecular sieves, for example, have high water adsorption capacities due to their microporous structure and affinity for water molecules. The water adsorption capacity is typically expressed as a percentage of the molecular sieve’s weight or volume. It can range from a few percent up to 20% or more, depending on the specific molecular sieve and the conditions of temperature and humidity. Molecular sieves are commonly used for drying applications, as they can effectively remove moisture from gases and liquids.