Re: Pressure Drop Calculation
Dear Shin Ho Kwon,
Pneumatic conveying systems for cement and barite (and bentonite) are typically products, used in the offshore industry.
These installations work with high pressure systems (4.5 to 5.6 bar) and low compressor volumes.
This makes it possible to use 6”connection hoses between a PSV (platform supply vessel) and a drilling rig and still reach an acceptable conveying rate.
Visit:
http://www.carlsengroup.com/
You indicate that you have executed 2 different calculations.
A previous calculation
The "Pneumatic Conveying Design Guide" method by David Mills with scaling up.
2 different calculations with 2 different outcomes must be considered as a warning.
One must be wrong and when you do not know which one is wrong, it could well be possible that they are both wrong.
And if you know which calculation is wrong, the next question would be why and where.
That is why calculation algorithms have to be correlated to existing installations.
The conveying properties of materials is depending on particle size (distribution), particle density and stickiness.
If one of these changes, the calculation changes (required air velocity and pressure drop)
However, the used materials show a fairly consistent behavior, as they also have to meets application standards.
Unless you are planning to enter the pneumatic conveying business, there is no point in starting your own research and even then, it would be as inventing the wheel again.
Have a nice day
Teus ■
Teus
Please, Check My Calculation Results From ScaleUp Method.
Dear, Teus Tuinenburg and all
First of all, thank you for your reply and advice.
I don't want to invent new wheel. I just want to modify current technology to fit up in my calculation case.
For the work, I need to analyze current technology and previous results.
Please, review my below results once again.
Line Information(Pipe Length and Bend Quantity  Material Information  Calculated Value  
SQ  Size (in) 
Inner Diameter(m)  Horizontal (m) 
Vertical (m) 
30Bend  45Bend  90Bend  Valve  Ybrench  Material  Transfer Rate 
Transfer Fluid 
Pressure Drop(bar) 
Air Flow Rate (m3/hr) 

1  5  0.128  59.4  17  10  5  6  5  2  Baryte  100tone/hr  Air  3.5  1290  
2  5  0.128  59.6  20  6  4  11  3  2  Cement  140tone/hr  Air  4.7  1560  
■
Re: Pressure Drop Calculation
Dear Shi Ho Kwon,
I ran your installations through “quick modeling “ and found the following results:
Barite:
56 tons/hr at 3.5 bar
vbegin = 6.5 m/sec
vend = 28.8 m/sec
Cement:
79.6 tons/hr at 4.7 bar
vbegin = 6 m/sec
vend = 35 m/sec
Assumed are standard ambient conditions and sea level.
Which current technology are you referring to?
Have a nice day
Teus ■
Teus
Re: Pressure Drop Calculation
Dear, Teus Tuinenburg
Thank you for your replay.
Actually, I claculated the data from "Pneumatic Conveying Desing Guide" to use scaleup method without margin and entry pressure loss.
(Detail Reference : Apendix 626page, Figure A2.7 and A2.8 [Length = 163m, Bore = 53mm, Bends  17*90degree, D/d = 4])
In accordance with your calculation, there is big diference.
I am really curious what method you used.
We got the below data via our previous test conducted in similar line.
Material Pressrue Drop Transfer Rate Air Rate
Barite 5.25bar 120ton/hr 1290m3/hr
And we got the below data via specialized engineering company in similar configure with differenc line size.
Material Pressrue Drop Transfer Rate Air Rate Line Size
cement 5.25bar 200ton/hr 1290m3/hr 6in
I doubt the cement calcualtion could be wrong.
The calculated result of cement is not matched with barite calculation.
The barite calculation is also calculated in same engineering company of cement.
According to their calcualtion, the transfer rate of barite is 100ton/hr. However, test results was over.
Because of a lot of doubts for pneumatic conveying system calculation method, I find and study new paper and book to get reasonable calcualtion results.
You throw one doubt to me. However, I will get reasonable results though this step.
If you don't mind, could you send your calcualtion method and source to me. My email address is bluenego@gmail.com
It will be great that anyone who watch this post and have good source recommend and send the source.
Have great happy day all. ■
Re: Pressure Drop Calculation
Dear, Teus Tuinenburg
Sincerely, I request that you calculate pressure drop to satisfy solid transfer rate(Barite : 100ton/h, cement : 140ton/h) given condition like my previous post and belows.
Have a great day.
Line Information(Pipe Length and Bend Quantity  Material Information  Calculated Value  
SQ  Size (in) 
Inner Diameter(m)  Horizontal (m) 
Vertical (m) 
30Bend  45Bend  90Bend  Valve  Ybrench  Material  Transfer Rate 
Transfer Fluid 
Pressure Drop(bar) 
Air Flow Rate (m3/hr) 

1  5  0.128  59.4  17  10  5  6  5  2  Baryte  100tone/hr  Air  3.5  1290  
2  5  0.128  59.6  20  6  4  11  3  2  Cement  140tone/hr  Air  4.7  1560  
[/ ■
Re: Pressure Drop Calculation
Dear Shin Ho Kwon,
I calculated the example [Length = 163m, Bore = 53mm, Bends  17*90degree, D/d = 4] that you refer to for cement.
The diagram A 2.7 (b) (cement) gives 12 tons/hr at 4.0 bar at an airflow rate of 0.0855 kg/sec.
My computer calculation results in:
10.8 tons/hr at 4.0 bar at an airflow rate of 0.0855 kg/sec.
Considering the uncertainties about the conveying conditions (s.a. temperature, cement properties, etc.), this result is reasonably acceptable.
My calculation method is described in:
https://news.bulkonline.com/pneumat...veying/65.html
We got the below data via our previous test conducted in similar line.
Material Pressure Drop Transfer Rate Air Rate
Barite 5.25bar 120ton/hr 1290m3/hr
And we got the below data via specialized engineering company in similar configure with different line size.
Material Pressure Drop Transfer Rate Air Rate Line Size
cement 5.25bar 200ton/hr 1290m3/hr 6in
For a pneumatic conveying calculation, I need the following information:
geometric description of pipe line (horizontal length, vertical length, number of bends, diameter(s))
Ambient conditions (Ambient temperature, intake temperature, altitude above sea level, RH)
Material properties (Material, particle density, bulk density, particle size (distribution), temperature)
Capacity or airflow.
feeding system (pressure tank, screw feeder, rotary lock)
If you can supply this information for the above test and specialized engineering company data, I can recalculate and possibly compare the differences.
Note:
At high conveying pressures, the capacitypressure curve becomes rather flat (low value of d(Cap)/d(p)), which results in high pressure fluctuations as a result of a small feeding fluctuation.
I doubt the cement calculation could be wrong.
The calculated result of cement is not matched with barite calculation.
The barite calculation is also calculated in same engineering company of cement.
According to their calculation, the transfer rate of barite is 100ton/hr. However, test results was over.
It is a wellknown fact that the pneumatic conveying capacity of barite is less than the capacity for cement.
[/quote]
According to their calculation, the transfer rate of barite is 100ton/hr. However, test results was over.
[/quote]
Obviously there is a mismatch between the calculation and the test.
This is not uncommon.
However, where the mismatch is generated is not so easy.
Because of a lot of doubts for pneumatic conveying system calculation method, I find and study new paper and book to get reasonable calculation results.
Although there are a lot of studies and books that describe the physics of pneumatic conveying, they seldom provide a userfriendly and/or reliable calculation method.
You throw one doubt to me. However, I will get reasonable results though this step.
If you don't mind, could you send your calculation method and source to me. My email address is bluenego@gmail.com
Although the principle of pneumatic conveying is simple, the calculation is far from that.
A pneumatic conveying calculation becomes complex, because of the inter related influences between velocity and pressure, SLR, temperatures, compressor characteristics, etc.
At this moment, I am not planning to publish the calculation method.
Sincerely, I request that you calculate pressure drop to satisfy solid transfer rate(Barite : 100ton/h, cement : 140ton/h) given condition like my previous post and belows.
Have a great day.
Line Information(Pipe Length and Bend QuantityMaterial InformationCalculated Value
SQSize
(in)Inner Diameter(m)Horizontal
(m)Vertical
(m)30Bend45Bend90BendValveYbrenchMaterialTransfer
RateTransfer
FluidPressure
Drop(bar)Air Flow Rate
(m3/hr)
150.12859.417105652Baryte100tone/hrAir3.51290
250.12859.620641132Cement140tone/hrAir4.71560
I gave the results in #4 of this thread.
Barite:
56 tons/hr at 3.5 bar
vbegin = 6.5 m/sec
vend = 28.8 m/sec
Cement:
79.6 tons/hr at 4.7 bar
vbegin = 6 m/sec
vend = 35 m/sec
Assumed are standard ambient conditions and sea level.
Have a nice day
Teus ■
Teus
Re: Pressure Drop Calculation
Dear, Teus Tuinenburg
I am very thank you for your kind reply.
The intend of the last part about calculation requests is that you calculate the pressure drop to be able to transfer solid transfer rate(barite : 100ton/hr, cement : 140ton/hr) in given pipe configuration.
I will have to review and study your recommending source tomorrow.
Have a great day. ■
Re: Pressure Drop Calculation
Dear Shin Ho Kwon,
I modeled the installation as follows:
horizontal length = 60 m
vertical length = 19 m
number of bends = 23
Compressor barite = 0.358 m3/sec (1290 m3/hr)
Compressor cement = 0.4333 m3/sec(1560 m3/hr)
conveying pressure = 4.7 bar
BARITE:
pipe line diameter 5” (128 mm) – capacity = 66.6 tons/hr at 4.7 bar
pipe line diameter 6” (154 mm) – capacity = 97.6 tons/hr at 4.7 bar
pipe line diameter 8” (203 mm) – capacity = 188 tons/hr at 4.7 bar
CEMENT:
pipe line diameter 5” (128 mm) – capacity = 79.6 tons/hr at 4.7 bar
pipe line diameter 6” (154 mm) – capacity = 113 tons/hr at 4.7 bar
pipe line diameter 8” (203 mm) – capacity = 210 tons/hr at 4.7 bar
Note that I used the same compressors for the 5”, 6” and 8” installations.
This means that the airflow for the 5”and 6”installation can be lowered.
At high conveying pressures (> 4.7 bar), the capacitypressure curve becomes rather flat (low value of d(Cap)/d(p)), which results in high pressure fluctuations (instable conveying) as a result of a small feeding fluctuation.
Normally, cement, barite and bentonite as applied in the offshore industry, are conveyed with the same pneumatic conveying installation.
Visit:
http://www.carlsengroup.com/
Have you asked the specialized engineering company to substantiate their calculations?
Take care,
Teus ■
Teus
Re: Pressure Drop Calculation
Dear, Teus Tuinenburg
Thank you for your kind reply.
I am late to post because of confirming your sentence that the transfer rate of cement is better than that of barite in same condition.
When I compare barite graph with cement graph, your sentence is incorrect. the graph is included in David Mills book.
(Detail Reference : Apendix 626page, Figure A2.7 and A2.8 [Length = 163m, Bore = 53mm, Bends  17*90degree, D/d = 4])
Therefore, I searched other paper and source, and found there is some kinds of cement.
The cement included in David Mills book is POC(Portland Ordinary Cement).
However, the cement of my case is OWC(Oil Well Cement).
In accordance with David Mills book, the Transfer property is different between POC and OWC.
The transfer rate of OWC is better than barite in same condition but that of POC is not.
Actually, I spent my whole time to find the property of OWC today. but I was not able to find the property
I arrange my calculation data like below.
I sincerely request that you calculate the below case, such as pressure drop, required air volume, etc. to satisfy solid transfer rate.
The particle property is referred to David Mills.
If you know the property of OWC(Oil Well Cement), please apply the property of OWC in calculation.
And apply 0.5bar to entry pressure loss, when you calculate.
Once again I really thank you. Have a happy day.
Case 1  Case 2  Case 3  Case 4  Case 5  Case 6  Case 7  Case 8  
Horisontal Length (m)  60  60  36  54  53  54  67  45 
Vertical Length (m)  17  20  33  33  33  10  9  10 
45degree bend  15  10  14  14  12  9  12  10 
90degree bend  6  11  7  7  9  5  8  5 
Valve  5  3  3  3  3  4  4  3 
Ybrench  2  2  1  0  1  2  1  2 
Diameter (mm)  128  128  154  154  154  128  128  128 
Ambient Temperature  15  15  15  15  15  15  15  15 
Intake Temperature  15  15  15  15  15  15  15  15 
Altitude Above Sea Level  0  0  0  0  0  0  0  0 
Material  Barite  Cement  Cement  Cement  Cement  Barite  Barite  Barite 
particle Density (kg/m3)  4250  3060  3060  3060  3060  4250  4250  4250 
Bulk Density (kg/m3)  1590  1070  1070  1070  1070  1590  1590  1590 
Particle Size (micro meter)  12  14  14  14  14  12  12  12 
Pressure Tank (bar) Entry pressure loss 
0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5 
Solid Transfer Rate (ton/hr)  100  140  210  200  188  157  121  169 
■
Re: Pressure Drop Calculation
In reality you will never achieve 4.7 barg at 80m. You will be lucky to reach 2  2.5 barg.
This will lead to higher pick up velocities and with the suggested airflows and lower conveying
pressures you will move into lean phase. Questions is will the SLR high enough to chock the
line or not at these velocities. Commercially the system is not viable one.
You are too high on air flows you need to look at reducing the air flows and bring back the system
into dense phase. It is standard to step the pipes if your conveying pressure is above 2 barg to reduce
the exit velocity. ■
Re: Pressure Drop Calculation
Dear Mantoo,
I must confess, that I have never witnessed a system that operated at 4.5 bar or over.
However, I operated a cement conveying system that reached 3.2 bar to 3.4 bar on a 10”/12” pipeline with a length of approx. 150 m.
Reaching a high pressure is only possible if the feeding is enough to reach the necessary SLR.
I calculated the volumetric loading ratio of the 2 material for the 6”installations:
barite:
0.1037 m3of material/m3 of air at the intake
mixture density at the intake = 197 kg/m3
SLR = 65.4 (Which is not an extreme value)
cement:
0.1829 m3of material/m3 of air at the intake
mixture density at the intake = 227.9 kg/m3
SLR = 78.2 (Which is not an extreme value)
I agree that systems above 2 bar should have a stepped pipeline.
However, in reality, a significant number of installations are built with one pipe diameter along the whole length.
As a consequence, the airflow is designed for the intake velocity and therefore the end velocity is somewhat too high.
This effect is stronger at higher conveying pressures.
Nevertheless, all pneumatic conveying installations on board of supply vessels and drilling rigs are designed for 5.6 bar to 6.0 bar at 5”or 6” lines.
See the link I gave earlier in this thread.
Calculations indicate that up to 4.5 or 5 bar, the conveying is stable plus the slope of the capacity curve is steep enough to absorb feeding fluctuations below the 5.6 bar.
I agree also with your argument that a shore based installation is best be designed for 2.5 bar.
Have a nice day
Teus ■
Teus
Re: Pressure Drop Calculation
Dear, all
Is there anyone who kwnow the difference between property of OPC(Ordinary Portland Cement) in pneumatic conveying system and that of OWC(Oil Well Cement) ?
Now, I calculate the pressure drop in drillship pneumatic conveying system with barite, cemment.
However, I searched that the cement used in drillship is OWC(Oil Well Cement).
I want to confirm that is collect from professional.
Have a great day all. ■
Re: Pressure Drop Calculation
Dear Shin Ho Kwon,
Since you are interested in the pneumatic conveying properties of cement and not in the chemical and structural properties, the only properties that are relevant, are the suspension velocity and fluidizability.
These 2 properties are related to the particle size distribution.
OPC and OWC are, in terms of pneumatic conveying, comparable as long as the particle size distributions are comparable.
Rather than calculating a drillship pneumatic conveying system for barite, cement and bentonite yourself, it is better to rely on a wellknown equipment supplier:
http://www.carlsengroup.com/
Pneumatic conveying calculations for offshore installations, where high conveying pressures of 4.5 bar to 5.6 bar are commonly used, are difficult to solve, due to the flat capacitypressure curve.
Take care
Teus ■
Teus
Re: Pressure Drop Calculation
Deae, Teus Tuinenburg
Actually, I don't know where I can find the sources I want in where you recommend.
I search whole site you recommend. However, I could not find I want.
I just know the difference of property between OPC and OWC.
that is why I want the comment of professional.
And Teus, you said you can calculate the information which is necessary for pneumatic conveying system if I supply some information about system figure. However, you could not reply anything for my requests. I really want to know that you can calculate my system especially high pressure system.
I just want to compare my calculation with previous field data.
The information between OPC and OWC is just needed for that step.
Now, I need some specific advise and recommend but the word to find specialist.
Anyway, thank you for your reply. ■
Re: Pressure Drop Calculation
Dear Shin Ho Kwon,
Actually, I don't know where I can find the sources I want in where you recommend.
I search whole site you recommend. However, I could not find I want.
Cement manufacturers who produce different types of cement present the differences in terms of:
chemical composition
curing times
ultimate strength
etc.
These data are not relevant for pneumatic conveying.
Furthermore, the cement can be delivered in various particle sizes given in microns or the so called Blaine number.
Blaine = 20303*SQRT(micron) in cm2/gram
The difference between OPC and OWC is negligible apart from the particle size.
However, OPC as well as OWC can be ordered with different Blaine numbers.
The particle size in combination with the particle density (resulting in the suspension velocity) is the only relevant pneumatic conveying property for calculating.
(The solid loss factor is probably the same)
Note, that the SLF is related to the calculation algorithm.
And Teus, you said you can calculate the information which is necessary for pneumatic conveying system if I supply some information about system figure. However, you could not reply anything for my requests. I really want to know that you can calculate my system especially high pressure system
Somehow, I missed your reply #10 in which you present a table of cases.
I notice that the particle size of 12 micron is very fine for cement.
I come back later on these cases.
I just want to compare my calculation with previous field data.
It might be easier to supply the previous field data and that I recalculate the field data and after that apply the derived values in the various cases.
Have a nice day
Teus ■
Teus
Pressure Drop Calculation
Dear, All professionals in Pneumatic Conveying system.
Now, I design pneumatic conveying system for barite and cement.
For designing this system, I have read "Pneumatic Conveying Design Guide" written by David Mills.
In accordance with this book, I use scallingup method. however, there are some gaps between my calculation and previous calculation.
We consider the 20% ~ 25% gap is margin caused by scallingup. I really want to confirm that it is margin and additional margin is necessary except for air velocity margin 20%.
And are there diverse kinds in barite and cement according to material property?
If there are diverse kinds, is the calculation results changed according to the kinds?
In that book, it is mentioned that the cement is ordinary portland.
My final purpose is making program to calculate pressrue drop in each point such as bend, verticla pipe, horisontal pipe and valve etc, as excel.
If there are Anyone who know paper and reference to make program, please recommend to me.
I really thank you for all to watch my post.
Have a great happy day. ■