Introduction to the Standard of Raschig Super Ring Plus

As a traditional packing commonly used in the chemical industry, Raschig rings need to follow certain standard specifications for production, performance, and application to ensure their stable performance in the mass transfer process. The following introduces the relevant standards of Raschig rings from aspects such as size, material, performance, and installation.

I. Size Standards

The size standards of Raschig rings mainly focus on the outer diameter (height) and wall thickness to ensure the consistency and interchangeability of the packing structure.

In industry general standards, the common outer diameter (height) size series of Raschig rings are clearly defined, including 6mm, 10mm, 16mm, 25mm, 38mm, 50mm, 76mm, 100mm, etc. For the same size specification of Raschig rings, the deviation of the outer diameter and height needs to be controlled within a certain range, usually requiring a deviation of no more than ±1mm to ensure a relatively regular packing layer when piled up.

Wall thickness: Different size Raschig rings have corresponding wall thickness standards. Small-sized Raschig rings have thinner wall thickness, such as 6mm Raschig ring with a wall thickness generally ranging from 0.8mm to 1mm; as the size increases, the wall thickness gradually increases, and the wall thickness of 100mm Raschig ring is usually between 3mm and 5mm, and the wall thickness deviation needs to be controlled within ±0.2mm to ±0.5mm (specifically depending on the size), to ensure the structural strength of the packing.

II. Material Standards

The materials of Raschig rings are diverse. Different materials need to comply with corresponding material standards to ensure their applicability in different working conditions.

Ceramic material Raschig rings

They need to comply with the relevant standards of ceramic materials. For example, in terms of acid resistance, they should be able to withstand certain concentrations of acidic medium corrosion, and their acid resistance rate should generally not be lower than 98%; in terms of physical properties, the compressive strength needs to reach certain indicators, generally not lower than 80MPa, and there should be no obvious cracks, corners, etc., to reduce damage during use.

Metal material Raschig rings

If it is carbon steel material, it needs to comply with the standards of carbon structural steel to ensure the stability of its chemical composition and mechanical properties, such as the tensile strength should be between 375MPa and 500MPa; stainless steel material needs to follow the standards of stainless steel materials, such as 304 stainless steel Raschig rings should meet the requirements of chromium content not lower than 18% and nickel content not lower than 8%, to ensure good corrosion resistance.

Plastic material Raschig rings

Common plastic materials such as polypropylene and polyethylene for Raschig rings need to comply with the corresponding plastic material standards, such as the melt flow rate, tensile strength, impact strength, etc. of polypropylene Raschig rings need to meet the standards, and the use temperature range should not have obvious deformation or performance decline, and it should have certain chemical corrosion resistance.

III. Performance Standards

Geometric Performance Standards

Specific surface area: The specific surface area of Raschig rings of different sizes has a general standard range, which is an important indicator for measuring their mass transfer potential. For example, the specific surface area standard value of 6mm Raschig ring is approximately 789m²/m³, and the specific surface area standard value of 100mm Raschig ring is approximately 19m²/m³. The deviation of the actual product's specific surface area should be controlled within ±5%.

Porosity: The porosity standard of Raschig rings is usually between 0.7 and 0.8, and the standard values of different sizes have slight differences, and the deviation between the actual measurement value and the standard value should not exceed ±3%, to ensure that the resistance and flux of gas passing through the packing layer are within a reasonable range.

Packing density: For Raschig rings of different materials and sizes, there are clear standard ranges for packing density. For ceramic materials, the standard value of the packing density for 25mm Raschig rings is 700kg/m³ - 800kg/m³, while for metal materials, 38mm Raschig rings have a packing density of 450kg/m³ - 550kg/m³. The actual packing density must be within the standard range to ensure the reasonable design of the tower equipment's load-bearing capacity.

Mass transfer and flow performance standards

In terms of mass transfer efficiency, although the mass transfer efficiency of Raschig rings is relatively lower compared to new types of packings, there are still basic standard requirements. Under specific experimental conditions (such as certain gas and liquid flow rates, temperatures, pressures, etc.), the height of the mass transfer unit must comply with relevant standards to ensure that basic separation effects can be achieved in simple mass transfer processes.

In terms of fluid resistance, the standard specifies the pressure drop range of different-sized Raschig rings under a certain gas velocity. For example, the pressure drop of 25mm Raschig rings under a specific gas velocity should not exceed a certain standard value to ensure that the energy consumption of gas passing through the packing layer is within a reasonable range.

IV. Application and Installation Standards

In terms of application scenarios, the selection of Raschig rings must comply with relevant process standards. Based on factors such as processing capacity, mass transfer requirements, and medium characteristics, choose the appropriate size and material of Raschig rings. For corrosive media, ceramic or stainless steel material Raschig rings should be preferred, and small-scale experimental devices can use small-sized Raschig rings.

In terms of installation, the stacking of Raschig rings in the tower should be uniform, avoiding situations where some areas are overly densely or sparsely packed to ensure uniform gas and liquid distribution. Before installation, the Raschig rings should be inspected, and damaged or deformed products should be removed. During installation, avoid violent collisions to prevent damage to the packings. At the same time, the height of the packings layer should comply with the process design standards to meet the requirements of the mass transfer process.