Dense Phase Advantages
A well designed dense phase pneumatic conveying system provides the following benefits:
- Low energy consumption
- Low maintenance and down time
- Low pipe wear
- Low material degradation
- Minimal segregation of blended materials
- Small ancillary equipment
More details below:
1. Low Energy Consumption
By conveying material below the saltation velocity in slugs of material the energy used per lbs/kg of material to lbs/kg of air is very low compared to dilute or vacuum systems.
2. Low MAINTENANCE
Due to very low velocity, pipeline life is usually several years, requiring little to no maintenance. In addition, most dense phase pneumatic conveying systems have few wearing parts, reducing the need for spare parts and maintenance. The combination of these factors result in reliable operating conditions with minimal down time.
3. Low Pipe Wear
As material is conveyed in a solid form, only a small percentage of particles conveyed are in contact with the pipe reducing pipe wear. This is important in conveying materials such as sand which can wear a hole in a pipe within several days.
There is a relationship between velocity and pipe wear as follows:
System B operates at 2.5 M/S
4. Low Material Degradation
The best regimes for preventing product degradation are discontinuous dense phase and solid dense phase. In these two regimes, two conditions exist:
(a) Low velocity
(b) Stable conditions, i.e., in a plug flow or solid dense phase regime there is no inter-particle activity. That is, particles do not collide with each other.
These two conditions combined produce very low rates of degradation – often with very fragile materials.
5. Minimal Segregation of Blended Materials
Many processes mix and blend two or more materials, e.g., glass industry, food processors, chemical processing, etc. Once the blending process is complete, the material must be conveyed without causing separation of the ingredients. Often, there is considerable difference in the characteristics of the ingredients, e.g., particle size, particle density, etc. If the conveying velocity is high, e.g., a dilute phase system, the individual particles will tend to convey at different velocities and separate as they are airborne.
The best regime for this application is the discontinuous dense phase.
6. Smaller ancillary equipment
Low energy consumption is advantageous for two reasons:
(a) Smaller filters may be used which will reduce the first cost of the system and subsequent maintenance costs.
(b) Smaller compressors and dryers may be used which will reduce the cost of the installations and reduce energy consumption.