Comparison of Dense Phase and Dilute Phase Pneumatic Conveying

Before comparing both of the above types, let us briefly understand what pneumatic conveying is. It is basically used to transfer bulk materials, particulates and powders through an enclosed conveying line. Differential pressure and the flow of air combination through the use of a fan is used during this transfer phase. The system will successfully convey bulk materials by controlling vacuum airflow forces and pressure inside the conveying line.

This pneumatic conveying system comes in two types. First is dilute phase, and second is dense phase. Both of the types work for different purposes according to their names. Let us compare both of the types.

Dilute Phase

This type conveys material at low pressure and with high velocity. A continuous conveying is done through the line. The accumulation on the bottom of the conveying line is prevented due to particulates remain suspended in the air.

Dilute Phase Vacuum Conveying:

This is a sub-method of dilute phase conveying and used to convey materials that tend to compress under pressure. It is basically used for short distance transportation.

Dilute Phase Pressure Conveying:

This is another sub-method of dilute phase conveying and used to convey lightweight particulates and powders. A high volume of low-pressure air is processed into the system at the start of the dilute pressure conveying phase.

Pros of Dilute Phase:

• Very economical and affordable
• Less maintenance is needed
• It can convey almost any material

Cons of Dilute Phase:

• Degradation of particulates and materials
• Higher power output leads to high expenses

Dense Phase

Another type of pneumatic conveying is the dense phase conveying through high pressure and low velocity. Basically in this type, the materials are pushed along or dragged to convey. It is the best choice when you want to minimize the damage to the materials.

Dense Phase Vacuum Conveying:

This sub-method is recommended to use when you want to transport potentially fragile or abrasive materials over a short distance. For example, bulk powders and particulates.

Dense Phase Pressure:

This sub-method is recommended to use when you want to transport super lightweight and fragile particulates over a long distance. For example, carbon black, glass batch mix, silica sand etc.

Pros of Dilute Phase:

• There is far less abrasion and wear to worry about in regards to the material since the velocity is much lower
• It is more energy-efficient method as compared to dense phase

Cons of Dilute Phase:

• In order to system be idle, air pressure must be high
• Sometimes installation, maintenance and overhead costs are increased due to additional fittings