Distillation Column Packing Materials
Distillation column packing material should have as large a surface area as possible and at the same time offer little resistance to the vapor and liquid inside the column. It should be easy to clean and should not settle or pack the column. The materials which are often used include Raschig rings, structured sheet metal, marble balls or stainless steel pads for washing dishes.
Standard rings - Raschig and Lessing cylindrical rings, cylindrical rings with dividers, saddle rings. The rings come from 25x25 to 50x50 mm diameter. Raschig rings are also made from ceramic. Improved rings - cylindrical rings and thin metal parts with different holes and deformations, springs. Packets - sheets of metal, wire, stainless steel or copper pads for washing dishes. Vertical packets of sheet of metal separated by 5-20 mm. The width of sheets corresponds to the width of a column. A few packets are inserted into the column in a crisscross pattern.
Horizontal packets of sheet metal.
Packing Materials for homemade columns
- Marble balls and ceramic scrap - cheap solution, but poor surface area.
- Raschig rings, stainless or ceramic - good surface area, available online.
- Stainless or copper scouring pads - good surface area, easy to get.
- Stainless or copper springs - very good surface area.
Copper oxidizes immediately and a copper scouring pad will be black after using it three times. It has to be cleaned by submerging it for 30 minutes in a solution of 1 Tablespoon of citric acid and 1 gallon of warm water. Then, rinse the copper parts with clean water and let it soak for about 12 hours in a bucket of 1 gallon of water to which 1 teaspoon of bicarbonate of soda (baking soda) has been added. This will neutralize any citric acid left over. Finally rinse again with clean water. Your copper will now be bright and clean. Stainless steel pads don't get easily dirty and can be washed with water. The proponents of copper pads claim that copper removes some of the sulfides from the alcohol mash thus improving its quality. This is true, but you don't need copper pads for that. Any piece of solid copper, a packing material holding screen or a piece of a solid bar of copper will accomplish the same and is easier to clean, for example with a fine sand paper.Stainless steel is a much better material for making columns, however, working with stainless steel requires considerable skills and expensive equipment. To weld stainless you need advanced welding skills and an expensive TIG welding machine. Copper is much softer, can be cut with aviation snipes or even scissors and soldering copper is easy. In addition many copper pipes and ready to assemble copper connectors and valves can be obtained in a plumbing supplies department of any larger store.