Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Please clarify your problem and give more data.
Thank you.
Reinhard H. Wohlbier ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
You will find plenty of data on both cement (OPC and oil well) and barite in my Pneumatic Conveying Design Guide - 2nd Edition, published in 2004 by Elsevier Butterworth-Heinemann. There is data on both materials conveyed through rubber hose as well as steel pipeline. If you prefer the information in US engineering units try my Handbook of Pneumatic Conveying Engineering published by Marcel Dekker (now CRC Press). ■
Data Of Dense Phase Pneumatic Conveying Of Cement/Barite
Thank you author and Dr Mills for your replies.
First of all, I want to say that the Textbook by Dr Mills is really great. Very informative. Thanks. I read several chapters already, but my loan was dued.
Anyway, for the field or experimental pressure drop data, it would be ideal if they are calculated in such a way that the inlet and outlet pressures are given after for each resstriction (e.g. straight horizontal/vertical pipes and bends) in the pipeline. It would really mean a lot to me because i'm doing a project right now on dense phase pneumatic conveying of cement/barite. My aim is to find out the pressure drop through the restriction mentioned above. Due to some unfortunate circumstances, i'm not able to carry out experiments myself. Thus, i won't able to verify my theoretical calculations with any experimental results.
I understand that pressure drops can be influence by many many factors and my way of doing this may be unorthodox, but i can't think of a better way.
Please advise if anyone has any idea.
Thank you all!
Regards,
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Matthew,
I can calculate the relevant parameters in a cement/barite conveying pipeline at any
desirable location as you request.
(for cement I have accurate data, for barite I do have also some data, but limited)
To perform such a calculation I need the piping geometry (diameter, length, angle and bends) and the data of the chosen compressor (type, displacement, maximum pressure).
Let me know those data together with the results of your theoretical calculations.
To check your calculations with an experiment would require building that installation, which would be a bit costly.
hear from you
teus ■
Teus
Data Of Dense Phase Pneumatic Conveying Of Cement/Barite
Dear Teus,
Thank for offering your help.
The piping geometry and other required data are given below:
Diameter - 12.7cm (5")
Layout -
25m horizontal, 90 degree long radius bend, 12m vertical, 90 degree long radius bend, 12m horizontal, 90 degree long radius horizontal bend and ends with a 5m horizontal pipe.
Operation is done by fluidizing the cement powders with a top discharge high pressure blow tanks with fluidizing membrane and a compressor (any type) with capacity of 300-700 cfm at an operating pressure of 60 psi (4.14 bars).
Air inlet velocity should be about 3 m/s.
The layout is suggested, and the results of the my pressure drop from all the restrictions cannot be done because my calculation will need an empirical factor to be determined first. Hence without doing the experiment i cannot calculate it.
Thus, i need a ready-run/available data in order to calculate the pressure drops in each restriction.
If anything else is needed, please inform me.
Thanks and Regards,
Matthew ■
Verifying Data
-deleted ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Matthew,
After modeling your system, the following result was calculated:
Matthew mat d 03-12-2007
Pressure discharge Cement
Convey length = 54 m
Nu of bends= 3
Pump vol = .14 + .14 m^3/s
q-convey = 0.14 m^3/s
Dia begin = 127 mm Dia end = 127 mm
Pipevolume = 0.68 m^3
------------Pipeline
Press.------Cap---------- mu ------------. v-begin----- v-end------- kWh/ton ------- res.time
4.000 ------129----------203 ------------- 4.5---------14.0 ----------0.37--------------10.56
3.500-------121----------190 ------------ 4.7 ----------13.9---------0.35--------------10.22
3.000-------111----------175 ------------- 5.0----------13.8---------0.32------------- 9.88
2.500-------101----------159 ------------- 5.4----------13.7---------0.30-------------9.46
2.000 --------90----------141 ------------ 5.8-----------13.6--------0.27 -------------8.98
1.500---------77----------120 ---------------6.3 ----------13.4--------0.25 -------------8.42
1.000---------59-----------92 ----------------7.1----------13.3 --------0.24 -------------7.81
0.500---------35----------54 ----------------9.0 -----------13.0-------- 0.27 ------------6.78
Empty pipeline pressure ...= 267.1 mmWC
The detailed data for the calculation for 3 bar(o) or 30000 mmWC are as follows:
5/5 111.4 tons/hr
Press: 30000
Press.drop :30000
Part--------length ----v-air------v-product-----press.drop
1 intake ---1.0 -----5.0 ------- 4.6 --------------1194
2 pipe-----24.0-----5.7---------5.2---------------8715.
3 bend --------------4.7--------2.0-------------- 8716.
4 pipe-----12.0-----9.4--------7.5--------------24440.
5 bend--------------9.4---------4.0 -------------24442.
6 pipe ----12.1-----11.6------10.2--------------27801.
7 bend-------------11.8--------5.5--------------27804.
8 pipe------5.1-----13.9-------12.0-------------29971
9 outlet------------13.9 -------12.0------------29982.
10 filter-------------0.2 -------------------------30000
v-filter 0.21 m/min
No booster > Length 54 M
Residence time 9.89 sec
36.kW
0.33 kWh/ton
Matthew Cement matd Re = 0.75
Matthew
***************
PRODUKT :Cement
Convey Length = 54 m
Number of Bends = 3 -
D-begin =127 D-end =127
Outlet force .. = 2145 N (dynamic)
Q-pump....................= 0.142 m^3/s
Q-convey-pipe ............= 0.142 m^3/s
Ambient temperature ......= 40.0 °C
backpressure at pipe-end..= 0. mmwC
NO BOOSTER
Pipeline capacity ........= 111.40 ton/hr
System-pressure...........= 30000. mmwC
loading-ratio ............= 175.11 -
T-Cement--------=41.9/ 42.1 Deg.C
Reynoldsnumber ..[ Re ]...= 0.75 --
Compr power .....= 36. kW
T-out compressor = 319. Deg.C
Mass in pipeline.= 569 kg
density product/air mix ..= 197.9 kg/m^3
spec.energy-consumption...= 0.33 kWh/ton
dp-accell.excl prod.rest..= 4753. mmwC
dp-suspension.............= 12625. mmwC
dp-lifting................= 5296. mmwC
dp-airfriction............= 125. mmwC
dp-productresistance......= 7075. mmwC
dp-intake productcolumn...= 100. mmwC
dp-intake ................= 7. mmwC
dp-nozzle ................= 1194. mmwC
dp-filter.................= 18. mmwC
Empty pipe dp....= 265 mmWC
The above calculation(s) now can be made for any chosen situation for air volume and pressure.
That will generate so many data, that it would become a problem to monitor them all.
In case you want to have calculated special situations, please let me know.
Note that the given capacities are pipeline capacities and are not corrected for the timelosses caused by a double kettle system.
Have fun
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Teus,
Thanks, it's amazing that you can generate those data.
However, there are a few terms i need to clarify with you.
1) what do cap, mu, residence time and dp mean?
2) Why are there pressure drops at the intake and outlet?
3) The filter is for separation right?
4) The total pressure drop is 3bars right? And is the velocity in m/min?
5) How is the density = 197.9 kg/m^3 calculated? Is it average of air and cement?
Lastly,
I would like to ask you one more favour. Is it possible for you to generate 3 or more sets of readings by changing the conveying condition (e.g. conveying velocity) so that i can calculate my empirical factor from one set and plot a trend to get the factors to verify my method of calculation from another set of readings.
That will be greatly appreciated. Thank you so much for everything Sir.
Regards,
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear matthew,
it is not that amazing. The computer does all the work.
1)
cap =capacity in tons/hr
mu = Solid Loading Ratio in (kg material/sec) / (kg air/sec)
residence time = time that a particle travels from the beginning of the pipeline to the end.
dp = (delta pressure) pressure drop (increment)
2)
The inflow of material to the intake requires a force that is generated by a pressure drop and air has to be accelerated.
Turbulence at the outlet consumes also some pressuredrop
3)
filter is for dust/air separation, so that the convey air can be released to the atmosphere clean.
4)
Total set pressuredrop is 3 bar(g) # 30000 mmWC
velocity in m/sec
5)
Mixture density is the weight of 1 m3 of product/air mixture
When you indicate the conditions you want to have calculated, the program will solve that.
best regards
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Teus,
Thanks a million for the explanation. I get it now.
However, if u could generate a few more data, it will really help me a lot. Sorry if i'm asking too much, and if it is cumbersome to generate them, then it's alright. You have helped me a lot already.
Thanks and Regards,
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
dear Matthew,
I can calculate some more conveying situations for you, no problem.
But if you indicate the situations you want to calculate, to meet your requirements, please let me know.
The you can get the most benefit of it.
best regards
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Teus,
Yes, i'll appreciate that if you can generate a few more sets of reading. The situation/pipeline layout will be the same as before. If you havent generate the data, please include these if possible, cement transfer flowrate of 60mt/h (This is what is given to me, if it is not a realistic number, you can don't include it), at an operating pressure of 60PSI, and min. -17 degree C dew point.
As for the readings you gave me the other time,
Part--------length ----v-air------v-product-----press.drop
1 intake ---1.0 -----5.0 ------- 4.6 --------------1194
2 pipe-----24.0-----5.7---------5.2---------------8715.
3 bend --------------4.7--------2.0-------------- 8716.
4 pipe-----12.0-----9.4--------7.5--------------24440.
5 bend--------------9.4---------4.0 -------------24442.
6 pipe ----12.1-----11.6------10.2--------------27801.
7 bend-------------11.8--------5.5--------------27804.
8 pipe------5.1-----13.9-------12.0-------------29971
9 outlet------------13.9 -------12.0------------29982.
10 filter-------------0.2 -------------------------30000
The pressure drop of the 1st pipe is (8715-1194) and 1st bend is (8716-8715), are they?
Is there any reason why the pressure drop in the bends so small?
Thank you and Regards,
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear matthew,
The calculation of 60 tons/hr at 60 psi (4.14 bar) will be made.
Low pressure drop over bend is explained as follows:
In a bend there will occur complete air-product segregation.
The only pressure drop is because of air friction.
The material slides against the outer wall of the bend, where it is decelerated.
After the bend, the material is entrapped in the air stream again and re-accelerated,
causing an increased pressure drop, due to the loss of velocity in the bend.
best regards
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Sliding flow in bends only happens in lean phase and is pretty much as described by Mr Teus. The actual bend pressure drop occurs in the straight section immediately after the bends known as “acceleration zone” and it is normally attributed to bend pressure losses. This is pretty much text book stuff.
But at the above mentioned solid loading ratios / velocities, which by all definitions is dense phase material will convey in plug flow. In plug flow there is no significant velocity loss in the bend because of low velocities and the plug already sliding on the pipe wall. For approximation in dense phase bend pressure losses are almost equal to the equivalent straight length.
For above mentioned distance for cement you will get a constant conveying rate of 60 tph in 5” line with exit velocity of 14m/s blow tank pressure will be between 1.8 - 2 barg. ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Teus and Mantoo,
Thanks for all the help so far.
Mr Mantoo,
What if the cement powders are conveyed in dense phase moving bed flow? Will this case be similar to the plug flow at all?
Can i approximate this pressure drop in bends like a straight pipe with a length, L, equal to a bend with radius of curvature, R?
How do you calculate the exit velocity of 14m/s blow tank pressure will be between 1.8 - 2 bar. If it's not convenient, its ok. Thanks
Regards,
Matthew. ■
5 D Long Radius Bend
Dear Teus,
I was just wondering if a 5D radius bend (with radius of curvature = 5 x diameter of the pipe) change the pressure drop data that you generate?
Regards,
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Moving bed or dune flow depends on material properties and conveying velocities (2-6 m/s range). Granular material like sugar salt etc. are conveyed in this mode. Dune flow is limited to first horizontal and as soon as flow moves form horizontal to vertical full bore plugs are formed which convey to the end conveying line end if the line is not stepped.
If you know your air flow rate at FAD exit velocity is calculated by dividing it with the cross sectional area of the conveying pipe. As far as conveying pressure drops are concerned they are from experience. I haven’t seen a reliable pressure drop predicting model for dense phase. Scaling from test plant data is used for designing purposes and is very reliable.
Your original post asking about the actual data was in the right direction. You can only get this data either from books as mentioned above or from some published papers (academic sources) only. Commercially all the good PC manufactures have test plants and have plenty conveying data but is never shared. ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Matthew,
The original calculation are for 1.5D bends (R-out = 0.191 m)
The result was 111.4 tons/hr at 3 bar
The recalculation for 5 D bends (R-out=0.7m) results in:
11.6 tons/hr at 3 bar.
Not much difference though.
The velocity losses in the 1.5D and 5 D bends are almost the same.
More over the bends form just a small part of the installation and therefore their influence is limited.
take care
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Correction:
111.6 tons/hr at 3 bar
sorry
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Matthew
Attached the promised calculations.
I calculated for 4 different air volumes for the same pipeline.
you will find the capacity = function (pressure) tables
and the velocity calculations for each air volume at 3 bar.
A 60 ton/hr installation can be designed with a smaller installation.
The chosen high pressure installation can be improved with stepped pipelines.
best regards
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear all,
esp Mr. Teus, Mr. Mantoo and Dr Mills, i'd like to express my gratitude to all of you who shared all your valuable experiences and knowledge of PC with a novice like me. Really appreciate the efforts, thank you all. Hope i wouldn't have many more questions to ask in future.
Best Regards,
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Teus,
From the generated data,
111.6 tons/hr, 120.6 tons/hr, & 116.8 tons/hr are the cement transfer rate recorded right?
Also, i realised for the 3 different cases, the pressure drops of the system are the same (3 bars). Is this set deliberately, or is it for pressure systems, the end of the conveying line is at atm pressure?
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
dear Matthew,
You are correct.
The figures in tons/hr are the cement rates (capacity) at 3 bar.
At the end of the conveying line thers is the filter pressure left (which is almost atmospheric)
The pressure of the compressor is completely used after the filter.
When I calculate a pneumatic conveying system, I want to know which capacity belongs to which pressure.
That requires that I choose one of the 2 as a set value.
In this case I chose the pressure to be set at 3 bar and calculated the corresponding capacity.
If you want it the other way around (pressure at a set capacity), that is also possible.
The installation is now modeled in the computerfiles and I can calculate in any setup now as you like.
success
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Teus,
That would be great!
I need to see the the pressure drops and their variations instead of it being set to 3 bars.
The conveying conditions and layout are still the same -
Consider a pressure type dense phase pneumatic conveying system transporting cement powder at 60 Ton/h (16.67 m/s) through a 5” (0.127 m) pipeline, at an operating pressure of 60 PSI (~4.14 bars). The layout is described to start with a 25 m horizontal line, followed by a 90o long radius bend, 12 m vertical line, 90o long radius bend, 12m horizontal line, 90o long radius bend and lastly a 5 m horizontal. Commercial steel pipes with surface roughness of 4.5 x 10-6 m are used. Other operating conditions include a minimum of -17 oC to keep the powder dry and a gas inlet velocity of 3 m/s.
Additionally, there is one problem encountered. What can be the inlet air density in this case if it is under high pressure and low temperate?
Thank you and sorry for the trouble to go through the calculation again.
Regards,
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Matthew,
I cakculated your installation for :
60 tons/hr
5 inch pipeline
various airflows until the pressure was approx 4 bar
Actually this is the Zenz diagram
Air flow---------pressure----------kwh/ton---------SLR------mix density
m3/sec----------mmWC----------------------------kg/kg----------kg/m3
0.06-------------40686---------------0.35----------220.7--------222.7
0.07-------------32133--------------0.32---------190.9-----------214.4
0.08-------------25229--------------0.29-----------167.0---------189.4
0.10--------------15319--------------0.24-----------133.6---------153.6
0.12--------------11337--------------0.22----------111.4----------129.2
0.14167---------10240--------------0.25-----------94.3-----------110.4
0.18--------------10277--------------0.31----------74.2------------87.8
0.24--------------11270--------------0.45----------55.7-------------66.6
0.28--------------11999--------------0.55-----------47.7------------57.4
0.32---------------12795-------------0.66-----------41.7-------------50.5
0.38---------------13917-------------0.83-----------35.2------------42.8
0.45---------------14633-------------1.03-----------29.7-------------36.4
If you plot this table into a graph you will see the Zenz diagram
success
teus ■
Teus
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Teus,
Thank you for all you have done. Really appreciate it.
Matthew ■
Re: Pneumatic Conveying Of Cement/Barite - Actual Field Data Ne…
Dear Matthew,
You are welcome
teus ■
Teus
Pneumatic conveying of cement/barite - Actual Field data needed
Hey people,
i would really appreciate if there are any kind ones who can send me a copy of actual field result of the pressure drops in the system. Thank you in advance!
Regards,
Matthew ■