Chemical Packing for Oil Refining

In the chemical unit operations such as distillation, absorption, and extraction in oil refining enterprises, specific performance chemical packings are required to optimize mass and heat transfer efficiency. The following is a detailed description of the commonly used types of chemical packings and their technical requirements:

I. Commonly used types of chemical packings in oil refining enterprises

1. Ring-shaped packings

Raschig Ring: Simple structure, mostly made of ceramics, metals, or plastics. Originally used in distillation and absorption towers, but with high resistance and low efficiency. Currently, they are gradually being phased out.

Pall Ring: Two layers of rectangular holes are opened on the wall of the Raschig Ring, and the inner curved blades enhance the gas-liquid distribution, reducing resistance by approximately 50% and increasing efficiency by 30%. Metal materials (such as stainless steel) are suitable for high-temperature, high-pressure, and sulfur-containing media (such as hydrogenation units).

Cascade Mini Ring: Height is only half of the diameter, with an expanded end, improving the contact between packings and liquid distribution. The mass transfer efficiency is 10% to 20% higher than that of the Pall Ring, and is often used in the initial distillation section of crude oil constant-pressure distillation towers.

2. Saddle-shaped packings

Arc Saddle (Berl Saddle): Ceramic material, with a curved surface. The liquid distribution is more uniform than that of the ring-shaped packings, but it is prone to stacking, resulting in a decrease in efficiency. It is now less used.

Intalox Saddle (Rectangular Saddle): Improves the symmetrical structure of the arc saddle to avoid stacking, has a higher void ratio, and is resistant to erosion. It is suitable for absorption towers (such as desulfurization towers), and the ceramic material is resistant to acid media (such as H₂S).

Metal Intalox Ring (Metal Saddle): Combines the advantages of ring-shaped and saddle-shaped packings, has a high opening rate, large flow rate, and low pressure drop. It is suitable for the main fractionating tower of catalytic cracking units and handling high-load oil-gas mixtures.

3. Plastic regular packing packings

Material is PP, PVC, etc., lightweight, resistant to low-temperature corrosion, suitable for normal temperature desulfurization towers (such as ethanolamine method for H₂S removal), but not resistant to high temperatures (usually ≤120℃). They are less used in oil refining.