Introduction
During shutdowns at refineries, petrochemical plants and chemical facilities, catalyst replacement involves far more than simply unloading a reactor and reloading it with fresh material. Between these two operations lies a critical process for optimising costs, enhancing safety and facilitating material management: catalyst screening.
This operation makes it possible to separate reusable particles from those that have lost their mechanical properties or have an unsuitable particle size, ensuring that only material meeting the required specifications proceeds to regeneration, reuse or final disposal.
At Lagupres, we provide Catalyst Handling services that include catalyst screening using specialised equipment, both in open atmosphere and under a nitrogen atmosphere whenever the characteristics of the product require it.
What Is Catalyst Screening?
Catalyst screening consists of classifying the catalyst by particle size using vibrating screens or sieves, separating the particles according to their size.
During years of operation inside the reactor, part of the catalyst may fracture as a result of mechanical stresses, thermal cycling or the chemical process itself. As a consequence, fines, dust and broken particles are generated that no longer meet the specifications established by the manufacturer or by the company responsible for its regeneration.
The objective of catalyst screening is to remove these unusable fractions and recover the maximum possible volume of catalyst that remains suitable for regeneration, reuse or further processing.
Why is Catalyst Screening Important?
Although it may appear to be a straightforward operation, catalyst screening provides significant benefits from both a technical and an economic perspective.
Its main benefits include:
- Maximising the recovery of reusable catalyst.
- Removing dust and broken particles.
- Facilitating catalyst regeneration.
- Reducing the volume of waste requiring disposal.
- Improving the quality of the recovered catalyst.
- Ensuring compliance with the specifications required by the client or the regeneration provider.
In certain processes, proper catalyst classification can result in significant cost savings by reducing the amount of catalyst that needs to be replaced with fresh material.
How is Catalyst Screening Carried Out?
The process begins once the reactor has been unloaded.
The catalyst is then conveyed to a vibrating screen fitted with one or more meshes of different apertures. The vibration distributes the particles across the screening surface, allowing only those smaller than the mesh opening to pass through.
As a result, the catalyst is separated into different fractions, which are subsequently stored independently for further processing.
Depending on the project requirements, the catalyst may be separated into:
- Dust and fine particles.
- Reusable catalyst.
- Oversized particles.
- Ceramic balls.
- Other materials present inside the reactor.
Screening Under Nitrogen and Screening in Air
Not all catalysts can be handled in contact with air.
Some materials, particularly certain catalysts used in hydrotreating or hydrocracking units, are pyrophoric or must be protected from oxidation in order to preserve their properties.
In such cases, the entire screening process is carried out under an inert nitrogen atmosphere.
The screening system remains completely enclosed, with oxygen concentration continuously monitored to ensure both operational safety and the preservation of the catalyst’s properties.
When the catalyst does not present these risks, screening can be carried out under normal atmospheric conditions, simplifying the operation and reducing processing time.
Types of Catalyst Screening According to Project Objectives
Every shutdown has different requirements, so the screening process is tailored to the type of catalyst and the desired outcome.
The most common screening operations include:
- Removal of dust and fines.
- Separation of fractured particles.
- Classification by different particle sizes.
- Automatic separation of ceramic balls.
- Multi-stage screening using multiple screens in sequence.
The screen configuration is selected according to the catalyst manufacturer’s technical specifications and the requirements established by the client.
Equipment Used for Catalyst Screening
Industrial screening operations are typically carried out using high-performance vibrating screens capable of operating continuously throughout the plant shutdown.
These systems may incorporate:
- One or more screening surfaces.
- Enclosed systems for screening under a nitrogen atmosphere.
- Dust extraction systems.
- Direct connection to Big Bags or Blow Bins.
- Pneumatic material conveying systems.
Selecting the appropriate equipment maximises operational efficiency while minimising catalyst losses.
Experience Is Key to Efficient Catalyst Screening
Although the operation of a screening unit may appear straightforward, achieving optimum results requires a thorough understanding of the behaviour of each catalyst type, the correct selection of screen meshes, and the appropriate configuration of the equipment to suit the characteristics of the material.
An incorrect classification can lead to the loss of reusable catalyst, increase the volume of waste generated, and complicate subsequent regeneration processes.
For this reason, catalyst screening forms an integral part of the specialised Catalyst Handling services provided by companies with extensive experience in reactor intervention and maintenance.
Do You Need Industrial Catalyst Screening Services?
At Lagupres, we provide specialised Catalyst Handling services covering the complete catalyst lifecycle, including reactor unloading, catalyst screening, classification, loading, and operations under inert nitrogen atmospheres.
We assess the characteristics of each reactor and develop the most suitable working procedure to maximise catalyst recovery, minimise shutdown time, and ensure the highest standards of safety throughout the entire operation.
If you would like more information about our catalyst screening services or require technical advice for an upcoming plant shutdown, our technical team will be pleased to assist you.
Frequently Asked Questions (FAQ)
What Is Catalyst Screening?
Catalyst screening is the process of classifying catalyst using screens or sieves to separate reusable particles from fines, dust and deteriorated fragments.
When Should Catalyst Screening Be Carried Out?
It is typically carried out after the catalyst has been unloaded from the reactor and before its regeneration, reuse or final disposal.
Do All Catalysts Need to Be Screened Under Nitrogen?
No. Only catalysts whose chemical properties or technical specifications require handling under an inert atmosphere to prevent oxidation or ignition hazards need to be screened under nitrogen.
Can the Support Material Also Be Separated?
Yes. Depending on the project requirements, the screening process can be used to separate ceramic balls, particles of different sizes, and other materials present inside the reactor.