Which One Is Best For Distillation Operation, Packed Or Tray Towers?

In the chemical process industry, distillation is an essential operation. The distillation process uses towers, packed or tray(plate). To better understand the distillation process, it’s vital first to understand the two types of towers. An important component of the distillation process is that the towers need to fit perfectly the distillation process and must also be able to handle all unforeseen issues. This is because accessing the fractional distillation column is not easy, nor is fixing it after an assembly. Looking deeply into the distillation towers, here are some differences to help you pick the best one for your needs.

The Basic Operations

Packed Towers

Packed towers provide a large surface area per unit volume to help facilitate the liquid-vapour mass transfer. The liquid and vapour are in constant contact as the liquid phase goes through the tower. This is different from the stepwise contact of the tray towers. Packed towers come in two designs:

• Structured Packing towers offer a large surface area with a lower pressure drop than packed towers. These designs can be of plastic (PTFE), perforated, embossed metal, wire gauze, or corrugated sheets. The result is usually an open structure like a honeycomb with only vertical flow routes providing a larger surface area to volume. However, the resistance to flow is quite minimal. These surfaces work best in maximising liquid spread.
• Random Packed Towers are made from nonmetal or metal materials like plastics and ceramics. The materials provide a surface area used in the distillation process.

If you’re looking for a car wash near you, be sure to check out, car wash near me now Many of these washes offer great deals on car washes and other services, so it’s a great way to start if you need a car wash.

Tray(plate) Towers

These have a special design to provide a liquid holdup to give room for a proper vapour-liquid mass transfer the distillation process needs for separation. The holdup is made possible by a weir found on each tray with stacks of horizontal trays. These trays allow the liquid to move across a tray before it eventually flows to a downcomer and then to the next distillation stage.

Furthermore, the liquid flow across the trays allows upward-moving vapour and the downward-moving liquids to have contact in a strategically placed passage in the tray. These passages include sieve trays, valve trays, and bubble cap trays.

Advantages And Disadvantages 

Choosing which distillation tower to use or which one is the best depends solely on your distillation process. Sometimes, you may be unsure of the best type to pick. If this is the case, you can reach out to the heavy equipment manufacturers to help create a process simulation. They will then calculate the column diameter to help you choose the best type of column to use. Some of the advantages of using these towers include the following:

Advantages of Packed Towers

•       Better at handling corrosive liquids
•       The best when it comes to handling foaming systems
•       They cause minimum pressure drop
•       Their liquid holdup is relatively low
•       Packed towers require minimum structure
•       They are relatively affordable and thus require low investment

Disadvantages Of Packed Towers

•       It’s impossible to remove side stream
•       They don’t work well with very low liquid rates
•       Providing cooling arrangements is not easy
•       They don’t offer accurate HTU and HETP predictions

Advantages Of Plate Towers

• They offer the best predictability when it comes to HTU and HETP
• Plate towers are better at handling different sources of fouling, including solids
• They are the best at handling liquids with lower rates
• They cause minimum pressure drop
• You can easily draw a side-stream from them
• They can scale up to larger diameters
• Cleaning and maintenance are pretty easy to handle with plate towers

Disadvantages Of Plate Towers

• Their supporting structures are pretty costly.
• They have a high liquid holdup, leading to a high-pressure drop.
• The cost of a plate column is pretty high if it has to handle corrosive liquids. This is due to the use of corrosion-resistant materials.
• Their performance reduces with foaming systems. To suppress this problem, you can use anti-foaming agents.

Which One Is The Best?

Choosing the best distillation tower depends on several factors, for instance, the fluid properties, capacity, pressure drop, efficiency, hold up, budgeting, and many others. However, the basic selection system is the cost of each and the profit you get. Sometimes, you can choose the one that best suits you depending on the quantitative analysis of their relative advantages and disadvantages.