Three dense-phase, low velocity pneumatic conveying systems were supplied to convey coal dust between 1.5t/h and 2.7t/h over a distance of 525ft horizontal and 30ft vertical. The systems were 2 x 3ft3 and a single 8 ft3 vessel all with a 3” convey pipe line. All pneumatic conveyors are located under a feed hopper with start and stop controlled automatically by the feed hopper and silo reception level probes. The material handling systems are working very reliably with no line blockages and exceed the customer’s expectation regarding transfer rate giving 2.9t/h for the smaller systems and 5.9t/h for the large system 1. The pipe line conveying pressure was between 8psi and 12.5psi. Convey air requirement was substantially less than that proposed at 88scfm and 180scfm. The proposed air requirement was 176scfm and 278scfm. The systems are pneumatic only to the ATEX equivalent of Eexd Class II Division 2. The customer elected to control the systems through their own high level PLC and DCS systems.
Coal dust 0.00016” – 0.004”
Coal pellets 0.2” – 0.4”
Bulk Density 25 lb/ft³
Moisture Content 0%
Condition Free Flowing
1. Dense phase low velocity conveying
2. ATEX zone 22 Cat 3D
3. Short delivery
4. Reliable operation
Transfer Capacity Between 1.5t/h and 2.7t/h
Conveying Distance 528ft Horizontal and 30ft vertical
Reception Points 1 feed and 2 reception points per system.
1. Increased transfer rate
2. Reduced compressed air requirements
3. Low than specified degradation