Over many years, pneumatic conveying threads are discussed in this forum, whereby it is noticed that in the recent years, the number of threads drastically dropped in numbers.

Most of the questions were about theory, quick answers, problem solving and many questions were asking for free engineering.

Also a number of forum members have contributed to the promotion of better understanding of the technology of pneumatic conveying.

However, a clear overview of the present state of knowledge is not easy to make.

Searching the internet, a lot of studies and theses are found, but they never result in a usable design procedure.

-The early pneumatic conveying designs were based on trial and error.

-After that scaling techniques were used, knowing that this technique was far from reliable for extrapolations.

-Companies used their own, some statistically based, methods and some used a method based on the relation between velocity head, solid loading radio and pressure drop.

All methods require material factors.

-When computers became available, the above methods were “computerized”

-With CFD computer programs, pneumatic conveying phenomena could be visualized and were very explanatory, but so far did not result in user friendly and reliable design software.

In addition, not only the pneumatic conveying parameters have to be considered, but also all the other influencing parameters and physics.

Over the years of my career in pneumatic conveying 1980 – present, I had the opportunity and the drive to study, describe, test end experiment with many pneumatic conveying installations in the field. (A 1 to 1 scaling lab)

This resulted in a pneumatic conveying computer calculation program as described hereafter.

INPUT

-Description of conveying route.

oLength horizontal

oLength vertical/slope

oPipe diameter(s)

oBends

-Description of material properties

oMaterial name

oMaterial density

oBulk density

oParticle size (distribution)

oSuspension velocity

oMaterial loss constant / material loss factor

oWall friction factor

oIntake pressure drop discharge (calculated in program)

oIntake pressure drop suction

ov-wall / v-suspension ratio

oFilter resistance factor

oMaterial specific heat constant

oGeldart class

oHausner ratio

oCarr Index

-Compressor types and properties

oOil free screw compressor with internal compression

oPD blower

oPD hybrid blower

oConstant mass pump. (sonic choke, turbo compressor, oil filled compressor)

oCompressor data curve operation points data base

oPredefined compressors and PD blowers

oCentrifugal fan

-Booster compressors

-compressor drive rpm droop

-Time increment calculation algorithm

-Ambient conditions

oTemperature

oCompressor intake Relative Humidity

oCompressor intake temperature

oAltitude

-Conveying gas

oAir

oNitrogen

oOxygen

-Predefined compressors and vacuum pumps

Calculated pneumatic conveying parameters (OUTPUT)

oCompressor gas flow

oGas volume retention in a tank system (replacement of discharged material)

oGas by pass volume in a tank system

oGas volume through conveying pipeline

oDryer/cooler water separation in gas supply

oGas leakage

Vacuum discharge rotary lock

Pressure feeding rotary lock

oBooster compressor gas flow

ogas velocities

oproduct velocities

opressure drops (per pipe section and total)

Product intake (calculated according pressure or fixed)

Nozzle pressure drop

Acceleration excluding product resistance

Product resistance

Bend extra resistance due to filled bend cross section.

Elevation

Suspension

Gas

Filter/cyclone

Gas supply piping

Vent piping

Compressor pressure

oSedimentation. (Local v-wall / v-suspension ratio)

oResidence time of a particle

oPresent mass in pipeline

oTemperature of product/gas mixture

oTemperature of pipe surface

oEnergy losses

oHeat losses

oBend gas- and material velocities.

oBend cross section material filling degree

oRH and condensation.

oCompressor pressure

oBooster pressure

oCapacity

oSolid Loading Ratio (SLR)

oConveying power

oCompressor power

oBooster compressor power

oEnergy consumption ( /ton )

oRe-Number

oMaterial loss factor (constant or formula)

oFeeders

Tank system

Screw feeder

Rotary lock

Eductor feeder

oFilter / Cyclone receivers

oSystem capacity

Filling time

Pressurizing time

Discharge time

Purge time

Cycle time

Tank system ( 1-vessel, 2-vessel, 3-vessel)

Screw feeder

Rotary lock

Eductor feeder

Bulk truck

oSystem energy consumption ( /ton )

oCapacity / pressure table

Additional Calculations

-Oil free screw compressors with internal compression

-Oil filled screw compressors with internal compression

-PD blowers

-PD hybrid blowers

-Eductor – venturi

-Self-operated pressure reducer.

-Cyclone

-Material particle size distribution

omean particle size for acceleration

omean particle size for suspension

-Air slides

-Bottom aeration

-Screw conveyor

-Filter fan power

-RH condensation

-Mesh – micron

-Quick modeling

-New installation modeling

-Cement unloader preliminary design

-Estimated capacity of cement, barite and bentonite installations.

-Bulk carrier dimensions

-Tank/silo pressure equalization.

-Compressor properties from performance curves.

-Storing data base text files

oCalculated installations

ocapacity/pressure curves

opressure/time curves for tank/silo pressure equalization

Calculation results applications

-Generating operational data for feasibility studies and economic evaluation.

-Generating operational data for locating malfunctions and fault finding.

-Calculation of special installations (Running 2 calculations parallel with manually entering shared parameters.)

oCoal injection systems with distributors

Application of ceramic control valve for capacity regulation and conveying stability.

1 feeder pipe into multiple injection lines

Shared distributor parameters are:

•distributor pressure

•Incoming capacity equals outgoing capacity

oVacuum/discharge conveyors cyclone, rotary lock

1 compressor serving as vacuum pump and discharge compressor.

Shared parameter is:

•Compressor gas flow vacuum system is equal to compressor gas flow discharge system.

oMultiple feeder systems, feeding into one common pipeline

Shared parameters are:

•Compressor gas flows

•Capacity feeder lines and capacity common line

•Pressure at combination point of feeder pipelines into common pipeline

Yarca pneumatic conveying software (www.yarca.nl) has these capabilities and possibilities. ■