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Re: Dense Phase Conveying System
dear sir
we are supplying the dense phase system for fly ash.
kindly send your enquiry and contact details to submit our proposal.
best regards
sanjay agarwal
sanjayagarwal.delhi@gmail.com ■
Re: Dense Phase Conveying System
Dear Aggarwal ji,
Thanks for your reply,but we first want to know the Company's name of yours so that we can initiate our correspondence further.
Regards,
Ranote ■
Our Contacts
parth engineering comp pvt. ltd.
ff06 , national arcade , plot no 4 , ghazipur LSC
TEL 011 22247974 CELL 9313055225 , 226
Originally posted by ranotek
Dear Aggarwal ji,
Thanks for your reply,but we first want to know the Company's name of yours so that we can initiate our correspondence further.
Regards,
Ranote
■
Fly Ash Calculation
Take fly ash Partical density as 1790kg/m^3,bulk density as 750kg/m^3, partical mean diameter as 100um.
conveying pipeline layout: horizontal length 1000m,vertical length 0m,bends number:5,valves number :2
calculation results:
fludizing vessel volume:2.5m^3
conveying time in pipeline:3min;
mean conveying velocity:19m/s
pipeline bore:231mm
solid loading ratio :13.7;
air volumetric flow:47.8Nm^3/min;
calculation fly ask conveying capacity:47.1t/h
i am not sure this calculation results is correct or correspond with reality very well.but i think it supplies you a reference to your design.
if you have any suggestion and commence ,please contact with me. my QQ number:22264251, QQ group number:31073767 MSN:JimLee170@hotmail.com
BR ■
Re: Dense Phase Conveying System
Mr Jim
Your calculations relate to a continuous conveying system, this will require either 2 parallel blow tanks or a lock vessel arrangement. If you are proposing single vessel then I am afraid the calculations are wrong. In my opinion 1000 m conveying distance is not financially attractive on running costs and power consumption. ■
Re: Dense Phase Conveying System
Dear above,
Base on the mentioned remarks and figures, I ran the computer and came up with the attached results.
Mr Jim did not mention the calculated pressure drop, which is a very important figure in pneumatic conveying.
Also the calculated conveying time of 3 min. seems to be too long
That indicates a particle velocity of 1000/180 = 5.55 m/sec.
Compared to a mean velocity of approx. 13.55 m/sec (not the end-velocity of 19 m/sec),
the particle velocity slip would be 13.55 – 5.55 = 8 m/sec (# 8/13.55 = 60 %)
Furthermore, the vessel content is low compared to the pipeline volume, resulting in high
purge time losses.
success
teus
Attachments
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Teus
Calculation
Mr Matoo, you are right the calculation results is based on the continous conveying system, there are two parallel bow tanks in this system.the volume of them are all 2.5m^3. In my calculation,i take the end(outlet) velocity(19m/s) as the mean velocity. the whole pressure drop of this conveying system is about 2.2Bar.So the inlet velocity is about 19/(2.2+1)=5.9375m/s. the real mean velocity is (outletvelocity+inletvelocity)/2=12.47m/s.Solid loading ratio is 13.6. the accurate calculation result of the conveying time is 2.9min.Datail calculation result please look at the attachment which is calculated by computer. if it is necessary i would like to translate it into english.
BR
Attachments
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Re: Dense Phase Conveying System
As I stated before for twin blowtank continuous conveying system the calculations are fine apart from residence time which is bit contentious as stated by above. ■
Dense Phase Conveying
Dear Sir
I am a new member of bulk-online. I just saw your information.We are a Chinese company which is specilized in pneumatic conveying. And we have cooperated with Cooperion for a long time.I wanner if we have the chance to cooperate with you.For more information please c heck our website http://www.zltchina.com.
Any question please feel free to contact me.
Maize Zhu
Changzhou ZLT Technology Co.,Ltd
Tel:0086-519-8325-1901
Fax:0086-519-8325-1908
Mobile:0086-137-7688-1318 ■
Re: Dense Phase Conveying System
Base on the mentioned remarks and figures, I ran the computer and came up with the attached results.
Mr Jim did not mention the calculated pressure drop, which is a very important figure in pneumatic conveying.
Also the calculated conveying time of 3 min. seems to be too long
That indicates a particle velocity of 1000/180 = 5.55 m/sec.
Compared to a mean velocity of approx. 13.55 m/sec (not the end-velocity of 19 m/sec),
the particle velocity slip would be 13.55 – 5.55 = 8 m/sec (# 8/13.55 = 60 %)
Furthermore, the vessel content is low compared to the pipeline volume, resulting in high
purge time losses.
success
teus
Sir how do i determine the purge time for given parameter of vessel volume (kettle content) and pipline volume?
Any equation will be helpful ■
Re: Dense Phase Conveying System
Dear kj,
The purge time of a pneumatic system is not that easy to calculate.
The purge time starts when the kettle is empty and the pipeline is still filled with material over the full length and the pressure is still the conveying pressure..
The purge time ends when the pipe line is empty over the full length and the pressure drops to the empty pipe line pressure.
The time, required for purging ist hen approx. equal to the residence time of the particles in the pipeline.
An approximation is:
purge time = factor * Conveying length / average particle velocity.
The factor depends on the pressure, where the purge time is considered ended.
Have a nice day
Teus ■
Teus
Re: Dense Phase Conveying System
The purge time of a pneumatic system is not that easy to calculate.
The purge time starts when the kettle is empty and the pipeline is still filled with material over the full length and the pressure is still the conveying pressure..
The purge time ends when the pipe line is empty over the full length and the pressure drops to the empty pipe line pressure.
The time, required for purging ist hen approx. equal to the residence time of the particles in the pipeline.
An approximation is:
purge time = factor * Conveying length / average particle velocity.
The factor depends on the pressure, where the purge time is considered ended.
Have a nice day
Teus
Ok thanks
But how would i determine the factor? . ■
Re: Dense Phase Conveying System
Dear kj,
The factor represents the part of the pipeline that is empty (purged) at the moment that you define the purging is complete.
If the pipe is still fully filled, the factor is: empty length/total length = 0 : pressure = conveying pressure
If the pipe is completely empty (purged) the factor is: empty length/total length = 1 : pressure = empty pipeline pressure.
Success
Teus ■
Teus
Re: Dense Phase Conveying System
The factor represents the part of the pipeline that is empty (purged) at the moment that you define the purging is complete.
If the pipe is still fully filled, the factor is: empty length/total length = 0 : pressure = conveying pressure
If the pipe is completely empty (purged) the factor is: empty length/total length = 1 : pressure = empty pipeline pressure.
Success
Teus
Taking this subject forward in attempt to eradicate my vague in this regard , i recall the previous thread
You said
The purging time of a pipeline starts after the kettle is empty.
The pipeline purging time is related to the particle residence time and is counted from the moment that the kettle is empty and the pressure in the pipeline has dropped to a value that makes it possible to change over to the next vessel.
1) To my understanding the purging starts after conveying time finished , so that sum of all teh time (purging+kettle filling+kettle pressurizing+conveying time ) represents the total cycle time . Now if that is true than purging will start after conveying completed . Please articulate on my understanding
You said
purging time of pipeline is taken as 75% of residence time = 0.75 * 100.9 = 75.6 sec.
Now if that holds correct that implies the purging time is 75% of conveying or residence time. Please explain the co-rrelation of this approach with first point
Now you said
purge time = factor * Conveying length / average particle velocity.
This implies the purge time is equal to residence or conveying time .
Sir please explain the final approach i consider to calculate the pipeline purging time . If your latest thread of
factor
implication holds good then pelase explain to calculate the factor ? ■
Re: Dense Phase Conveying System
Dear kj,
Again, the purging time of a pipeline starts after the kettle is empty and the pipeline is still filled with material.
The purging time ends when the pipeline is purged for a defined length.
The defined, purged length is related to the conveying pressure.
Example:
Conveying pressure of filled pipeline = 2.5 bar
Pressure of empty pipeline = 0.1 bar
Pressure of half filled pipeline = (2.5-0.1) * (1- 0.5) = 1.2 bar
Pressure of 75% purged pipeline = (2.5-0.1) * (1- 0.75) = 0.6 bar ( purge end pressure)
As the purging of a pipeline is a transient event, this method has to be regarded as a practical approximation.
The factor (in the example 0.75) depends on the chosen purge end pressure.
Success
Teus ■
Teus
Re: Dense Phase Conveying System
![Quote Quote](images/misc/quoteicon.png)
href="showthread.php?p=69919#post69919" rel="nofollow">
Again, the purging time of a pipeline starts after the kettle is empty and the pipeline is still filled with material.
The purging time ends when the pipeline is purged for a defined length.
The defined, purged length is related to the conveying pressure.
Example:
Conveying pressure of filled pipeline = 2.5 bar
Pressure of empty pipeline = 0.1 bar
Pressure of half filled pipeline = (2.5-0.1) * (1- 0.5) = 1.2 bar
Pressure of 75% purged pipeline = (2.5-0.1) * (1- 0.75) = 0.6 bar ( purge end pressure)
As the purging of a pipeline is a transient event, this method has to be regarded as a practical approximation.
The factor (in the example 0.75) depends on the chosen purge end pressure.
Success
Teus
Sit
To put the matter in more easy way , pelase refer attached your design sheet
1) Purge time determined in this is 86 Sec . Would you pelase explain how ?
Attachments
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Re: Dense Phase Conveying System
Dear kj,
As explained before:
purge time = factor * residence time.
In the example design sheet:
purge time = 0.75 * 114.29 = 86 seconds
Have a nice day
Teus ■
Teus
Re: Dense Phase Conveying System
This implies
1) To purging time is always 75% of residence time
2) What is difference between residence time and discharge time. I understand the residence time is the time requuired to convey the material from source to destination , whereas dischrage time is the total time (Conveying time + Cycle gap timer time) to convey the material . Please correct me with my understanding ? ■
Re: Dense Phase Conveying System
Dear kj,
1) To purging time is always 75% of residence time
The factor depends on how far the conveying pressure is dropped until the level that you consider as “pipeline purged”.
Reread reply #16 of this thread.
The discharge time is defined as the time that there is flowing material out of the kettle.
The discharge time starts when the kettle is pressurized and the discharge valve opens.
The discharge time ends at the moment when the kettle is empty and the pipeline is full.
Discharge time = Kettle content / capacity
Have a nice day
Teus ■
Teus
Re: Dense Phase Conveying System
The factor depends on how far the conveying pressure is dropped until the level that you consider as “pipeline purged”.
Reread reply #16 of this thread.
The discharge time is defined as the time that there is flowing material out of the kettle.
The discharge time starts when the kettle is pressurized and the discharge valve opens.
The discharge time ends at the moment when the kettle is empty and the pipeline is full.
Discharge time = Kettle content / capacity
Have a nice day
Teus
Sir
What is real significance of discharge time? , because as i understand
Total time per cycle = Vave filling time + Pressurizing time +Conveying (residence) time + Purging time + venting time
For instance in the previous attached sheet
589.9 (Total time) = 19.6(pressurizing)+86(purging) +114 (residence) +2 (valve time) kettle idle time
Hence kettle idle time= 368 second
Please comment ■
Re: Dense Phase Conveying System
Dear kj,
Total time per cycle = Valve filling time + Pressurizing time +Conveying (residence) time + Purging time + venting time
No, this is not complete:
The total time per cycle is the sum of the subsequent events during the unloading of a pressure vessel between the opening of the pressurizing valve until the closing of the discharge valve.
Therefore:
Total time per cycle = Pressurizing time +Conveying (vessel emptying) time + Purging time + valve time + filling time in case of a one vessel system.
Hence:
589.9 (Total time) = 19.6(pressurizing)+86(purging) +482.2 (vessel emptying) +2 (valve time) kettle idle time
Take care
Teus ■
Teus
Re: Dense Phase Conveying System
No, this is not complete:
The total time per cycle is the sum of the subsequent events during the unloading of a pressure vessel between the opening of the pressurizing valve until the closing of the discharge valve.
Therefore:
Total time per cycle = Pressurizing time +Conveying (vessel emptying) time + Purging time + valve time + filling time in case of a one vessel system.
Hence:
589.9 (Total time) = 19.6(pressurizing)+86(purging) +482.2 (vessel emptying) +2 (valve time) kettle idle time
Take care
Teus
Sir , i once again drag the matter to my previous query
what is major difference between discharge time and resdence time?
My perception is , discharge time starts after vessel is empty and pipeline is full with material
Residence time implies the material convey time , henec if we have to take the realy cycle time into consideration , that shall replace teh discharge time by residence time (convey time) balance time shall be idle time
please articulate ■
Re: Dense Phase Conveying System
Dear kj,
It is a matter of definition.
Discharge time is the time that the vessel is being discharged.
Residence time is the time that a particle is traveling in the pipe line.
Have a nice day
Teus ■
Teus
Dense phase conveying system
Sir,
can any body have some design calculations for finding conveying pipe size,capacity of comressors for conveying dry fly ash,capacity of vessels etc. to convey 45 Ton/Hr dry fly ash of Bulk Density of 700-800kg/cu.m to a distance of 1000 mtr.
I am working in a Cement Industry and engaged in Flyash Projects.
Ranotek ■