Power Consumption
Understand that KW/t/100m has no meaning as a generalized expression because it does not take into account the pressure loss characteristics of the specific material conveyed.
It can be useful, however, as an empirically derived expression for a specific material.
Dennis Hauch, PE ■
Re: Power Comsumption For Air Conveying
Dear Shengie2004,
Powerconsumption can be calculated when an installation and the product (conveying properties) are known.
You state : 1.5 kWh/ton - 100m , indicating that you have an example available.
If you give the details of that example, may be we can work out a better answer.
f.i. Is the 1.5 kWh/ton-100m horizontal or vertical upwards or vertical downwords and what product is conveyed at what speed ?
best regards ■
Teus
Re: Power Comsumption For Air Conveying
Originally posted by Teus Tuinenburg
Dear Shengie2004,
Powerconsumption can be calculated when an installation and the product (conveying properties) are known.
You state : 1.5 kWh/ton - 100m , indicating that you have an example available.
If you give the details of that example, may be we can work out a better answer.
f.i. Is the 1.5 kWh/ton-100m horizontal or vertical upwards or vertical downwords and what product is conveyed at what speed ?
best regards
PE Pellet, Horizontal distance: 90m, Raising: 12m, Bend: 4
Dn125,
30kW Roots Blower ■
Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]
Re: Power Comsumption For Air Conveying
Originally posted by Teus Tuinenburg
Dear Shengie2004,
Powerconsumption can be calculated when an installation and the product (conveying properties) are known.
You state : 1.5 kWh/ton - 100m , indicating that you have an example available.
If you give the details of that example, may be we can work out a better answer.
f.i. Is the 1.5 kWh/ton-100m horizontal or vertical upwards or vertical downwords and what product is conveyed at what speed ?
best regards
PE Pellet, Horizontal distance: 90m, Raising: 12m, Bend: 4
Dn125, Cap: 15T/h
30kW Roots Blower ■
Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]
Specific Energy
I tend to work in terms of specific energy, in kJ/kg, and use this as a basis for comparison of different systems operating under similar conditions. There are just too many variables to allow representative single figures to be quoted.
For polyethylene pellets conveyed over 100 m in the pipeline that you specify the specific energy is very dependent upon conveying line inlet air velocity. At 22 m/s the specific energy is about 27 kJ/kg and this gradually reduces to about 16 kJ/kg at 13 m/s. With further decrease in velocity it increases because of the transition from dilute to dense phase.
These figures, of course will vary also with conveying line pressure drop and pipeline bore. ■
Re: Specific Energy
Originally posted by Dr David Mills
I tend to work in terms of specific energy, in kJ/kg, and use this as a basis for comparison of different systems operating under similar conditions. There are just too many variables to allow representative single figures to be quoted.
For polyethylene pellets conveyed over 100 m in the pipeline that you specify the specific energy is very dependent upon conveying line inlet air velocity. At 22 m/s the specific energy is about 27 kJ/kg and this gradually reduces to about 16 kJ/kg at 13 m/s. With further decrease in velocity it increases because of the transition from dilute to dense phase.
These figures, of course will vary also with conveying line pressure drop and pipeline bore.
Mr. David,
You mean 13M/s for PE? Is this speed performance good and stable?
1 KWH=3600KJ
So 16kJ/kg=16*1000/3600/ton=4.44kWH/ton/100m? ■
Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]
Conveying Air Velocity
Virtually any conveying air velocity is possible with polyethylene pellets. If you are only designing a system for dilute phase flow, however, you must stay well above 13 m/s. If you are concerned about angel hairs or streamer formation you may well choose to convey at a velocity below 13 m/s and accept the higher value of specific energy. If you design for low velocity, dense phase flow, system control become critical because the lines of constant conveying line pressure drop converge below the pressure minimum point. ■
Re: Conveying Air Velocity
Originally posted by Dr David Mills
Virtually any conveying air velocity is possible with polyethylene pellets. If you are only designing a system for dilute phase flow, however, you must stay well above 13 m/s. If you are concerned about angel hairs or streamer formation you may well choose to convey at a velocity below 13 m/s and accept the higher value of specific energy. If you design for low velocity, dense phase flow, system control become critical because the lines of constant conveying line pressure drop converge below the pressure minimum point.
Yes I am discussing dilute phase.
Can I draw a conclusion that for most of plastic pellet similar to PE I can choose pick up speed as 13m/s or a little bit higher?
In your experience for normal 10D pipes and SS304 pipes how many PPM fine powder or streamer will be generated for a 100m pipe with 13m/s pick up velocity?
Thanks ■
Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]
Dilute Phase For Ldpe
Try 18 m/s and reduce if you have no problems. With a one bar compressor and a single bore pipeline you are looking at about 100 PPM (g/tonne) at a solids loading ratio of about 2 and about 60 g/tonne at a solids loading ratio of about 10. This will also vary with pipeline bore, number of bends, surface finish, etc. ■
Re: Dilute Phase For Ldpe
Originally posted by Dr David Mills
Try 18 m/s and reduce if you have no problems. With a one bar compressor and a single bore pipeline you are looking at about 100 PPM (g/tonne) at a solids loading ratio of about 2 and about 60 g/tonne at a solids loading ratio of about 10. This will also vary with pipeline bore, number of bends, surface finish, etc.
Verrrrrrrrrrrrrrry goooooooooooooooddddd!!!
And which is the main cause for PPM? pipeline bore or bends?
for example:
30m horizontal-> horizontal bend->20m horizontal->vertical bend->30M raise vertical->V-H bend->20M horizontal-> drop bend ■
Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]
Re: Dilute Phase For Ldpe
Originally posted by Dr David Mills
Try 18 m/s and reduce if you have no problems. With a one bar compressor and a single bore pipeline you are looking at about 100 PPM (g/tonne) at a solids loading ratio of about 2 and about 60 g/tonne at a solids loading ratio of about 10. This will also vary with pipeline bore, number of bends, surface finish, etc.
Verrrrrrrrrrrrrrry goooooooooooooooddddd!!!
And which is the main cause for PPM? pipeline bore or bends?
for example:
30m horizontal-> horizontal bend->20m horizontal->vertical bend->30M raise vertical->V-H bend->20M horizontal-> drop bend ■
Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]
Particle Degradation
It is very difficult to isolate the influence of bends and straight pipeline in assessing particle degradation effects. For most materials bends are generally considered to be the dominant factor and I do not expect it to be any different for LDPE. It will probably be best to avoid long radius bends. ■
Re: Particle Degradation
Originally posted by Dr David Mills
It is very difficult to isolate the influence of bends and straight pipeline in assessing particle degradation effects. For most materials bends are generally considered to be the dominant factor and I do not expect it to be any different for LDPE. It will probably be best to avoid long radius bends.
Thank you David for your helpful answers.
Have you any comment for different bends about pressure loss and efficiency for PPM?
1. 10D bend
2. 5D bend
3. "T" bend
4. Gammar bend or other special bends
Regards ■
Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]
Power comsumption for air conveying
Who can tell from your experiance the power consumption.
XXX KWH/Ton/100m
1. dilute phase pushing
2. dilute phase pulling
3. dense phase AirControlUnit
4. dense phase sending tank
5. twin pipe...
I made 1.5KWH/ton/100m for item 1
and who can tell how to reduce those power consumption ■
Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]