Advantages and disadvantages of Raschig ring packing

- Sep 11, 2019-

Artificial particle fillers are mainly divided into two categories from shape structure, one is annular packing; the other is saddle ring packing. In addition, there are some small varieties of other shape fillers, such as annular fillers, flower ring fillers, etc., which are used in small quantities and applications.

Today we are talking about the Rasch ring packing. According to the material, it is divided into ceramic Raschig ring, metal Raschig ring and plastic Raschig ring.

The Raschig ring is the oldest and most primitive shape of the annular packing. It is a hollow ring of equal height and diameter. It is made of ceramic material and has a wall thickness of one tenth of the outer diameter.

1. Laxi ring has large fluid resistance

2, the specific surface area of the Raschig ring

In order to obtain a larger filler specific surface area, a spacer or spiral channel is added inside the Raschig ring, which becomes a cross spacer ring and a spiral ring packing, but these changes fail to fundamentally change the liquid distribution of the Raschig ring packing layer. Uniform, easy to produce adverse effects such as channel flow, bias flow and wall flow. The wall flow effect causes a considerable portion of the circulating fluid pumped to the upper part of the tower to flow along the wall of the tower, without participating in the surface of the wetted packing, wasting the power of the pump.

The Raschig ring also has a serious defect, its surface is not easily wetted, and the surface area of the filler is not fully utilized.

3. Improved type of Raschig ring

After the use of the Laxi ring in the chemical and refining industries for a hundred years, it was realized that the Laxi ring fluid resistance and the poor liquid distribution performance were caused by the discontinuity of the gap between the fillers. Improvements to the Raschig ring have resulted in a short Raschig ring with a height to diameter ratio of 1/2. The gap between the fillers is continuous, and the fluid resistance and mass transfer performance are improved to some extent.

China also studied the Lacy ring in the late 1970s, but it was too late. Because the saddle-shaped packing has appeared at that time, its performance is better than the short Laxi ring, so it is not necessary to further study and develop a short Raschig ring.