Dear Mr. Agarwal,

Thank you for the article that you sent to me, it is a help for me, i can use it to validate a design.

more power to you,

Marlon M

HWC ■

Dear Mr. Agarwal,

Thank you for the article that you sent to me, it is a help for me, i can use it to validate a design.

more power to you,

Marlon M

HWC ■

Many thanks for the article Amrit. It is well detailed and a great reference.

Cheers ■

Many thanks for the article Amrit. It is well detailed and a great reference.

Cheers ■

Originally Posted by Amrit Agarwal

My article "Theory and Design of Dilute Phase Pneumatic Conveying Systems" was published this month in Powder Handling and Processing magazine. This article gives an easy to use Excel-based calculation method for designing new dilute phase pneumatic conveying systems or for improving the performance of existing conveying systems.

Regards,

Amrit T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services

Email: polypcc@aol.com

Ph and Fax: 304 346 5125

Dear Mr. Amrit Agarwal,

Thank you very much for sending me the article. It is really very good one. I have made my own excel calculation based on your paper. I would like to know whether the same methodology can be used for calculating Dense Phase Conveying system?. How to calculate Solid/Gas ratio if actual Gas flow rate is not known?.

Regds,

Thennarasu. ■

Originally Posted by Amrit Agarwal

My article "Theory and Design of Dilute Phase Pneumatic Conveying Systems" was published this month in Powder Handling and Processing magazine. This article gives an easy to use Excel-based calculation method for designing new dilute phase pneumatic conveying systems or for improving the performance of existing conveying systems.

Regards,

Amrit T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services

Email: polypcc@aol.com

Ph and Fax: 304 346 5125

Dear Mr. Amrit Agarwal,

Thank you very much for sending me the article. It is really very good one. I have made my own excel calculation based on your paper. I would like to know whether the same methodology can be used for calculating Dense Phase Conveying system?. How to calculate Solid/Gas ratio if actual Gas flow rate is not known?.

Regds,

Thennarasu. ■

Dear Thennarasu,

The Solid/Gas ratio (SLR) is defined as :

SLR = material flow / gas flow

Apparently, you know the material flow.

One equation with two unknown variables cannot be solved.

The only way out is to assume one of the two unknown variables and calculate the remaining variable.

Whether you assumed the right value for your application has to be checked with a full pneumatic conveying installation calculation.

If your guess was wrong, the full calculation fails or results in unwanted velocities, pressures or else, then a new assumption, followed by a recalculation is required.

This is an iteration process.

What is your interpretation of dense- and dilute pneumatic conveying?

Take care

Teus ■

Dear Thennarasu,

The Solid/Gas ratio (SLR) is defined as :

SLR = material flow / gas flow

Apparently, you know the material flow.

One equation with two unknown variables cannot be solved.

The only way out is to assume one of the two unknown variables and calculate the remaining variable.

Whether you assumed the right value for your application has to be checked with a full pneumatic conveying installation calculation.

If your guess was wrong, the full calculation fails or results in unwanted velocities, pressures or else, then a new assumption, followed by a recalculation is required.

This is an iteration process.

What is your interpretation of dense- and dilute pneumatic conveying?

Take care

Teus ■

Originally Posted by veetee

Dear Mr. Amrit Agarwal,

...

I would like to know whether the same methodology can be used for calculating Dense Phase Conveying system?

Regds,

Thennarasu.

Dear Thennarasu,

Upon my query (#352 of this thread) Amrit Agarwal was to kind to answer this question in the post #355.

Quote

" 6. Calculation method is applicable to dilute phase only, up to the minimum pressure point. For calculations to be correct, solids velocity must be higher than the saltation velocity.

Unquote

As per definition Dense phase conveying starts below the saltation velocity and the limitation of the methology becomes clear.

The friction factor K is not a constant or a linear function of the gas velocity and therefore the model should fail.

Best regards,

Sven ■

Originally Posted by veetee

Dear Mr. Amrit Agarwal,

...

I would like to know whether the same methodology can be used for calculating Dense Phase Conveying system?

Regds,

Thennarasu.

Dear Thennarasu,

Upon my query (#352 of this thread) Amrit Agarwal was to kind to answer this question in the post #355.

Quote

" 6. Calculation method is applicable to dilute phase only, up to the minimum pressure point. For calculations to be correct, solids velocity must be higher than the saltation velocity.

Unquote

As per definition Dense phase conveying starts below the saltation velocity and the limitation of the methology becomes clear.

The friction factor K is not a constant or a linear function of the gas velocity and therefore the model should fail.

Best regards,

Sven ■

Dear Sven,

You state:

“The friction factor K is not a constant or a linear function of the gas velocity and therefore the model should fail”

I fully agree that the friction factor K is not a constant or a linear function of the gas velocity.

However, that counts for both dilute- and dense phase pneumatic conveying.

Are you indicating that the calculation method, as referred to in Mr Agarwal’s reply #6, for dilute phase also fails?

If this is true, then serious considerations regarding the calculation method have to be made.

Have a nice day

Teus ■

Dear Sven,

You state:

“The friction factor K is not a constant or a linear function of the gas velocity and therefore the model should fail”

I fully agree that the friction factor K is not a constant or a linear function of the gas velocity.

However, that counts for both dilute- and dense phase pneumatic conveying.

Are you indicating that the calculation method, as referred to in Mr Agarwal’s reply #6, for dilute phase also fails?

If this is true, then serious considerations regarding the calculation method have to be made.

Have a nice day

Teus ■

Originally Posted by Teus Tuinenburg

Dear Sven,

You state:

“The friction factor K is not a constant or a linear function of the gas velocity and therefore the model should fail”

I fully agree that the friction factor K is not a constant or a linear function of the gas velocity.

However, that counts for both dilute- and dense phase pneumatic conveying.

Are you indicating that the calculation method, as referred to in Mr Agarwal’s reply #6, for dilute phase also fails?

If this is true, then serious considerations regarding the calculation method have to be made.

Have a nice day

Teus

Dear Teus,

all the friction factor curves I have seen indicate that the friction factor K follows a curve that can be expressed as

K = a * x^(-b) + c

where K is the friction factor and x a number related to the terminal velocity. What physical condition/effect the variable a and the constant c describe I dare not say.

From above equation it is obvious that for increasing x-values (velocities) the K-value approaches the value of the constant c.

Therefore, for high x-values, the K-factor may be considered a constant in a first approximation.

If the K-factor in the calculation method suggested is chosen large enough and the lower velocity limit is clearly defined there can only be an over-estimation of the calculated pressure loss due to friction.

All other pressure loss calculations suggested are only affected by a potentially higher gas density after each step.

As for every theory applied in pneumatic conveying serious consideration is advised as to the limitations and validity range of the calculation model used.

When reading this thread from the start, which is quite tedious and for sure not often done, there are a couple of posts, which reflect above.

Best regards,

Sven ■

Originally Posted by Teus Tuinenburg

Dear Sven,

You state:

“The friction factor K is not a constant or a linear function of the gas velocity and therefore the model should fail”

I fully agree that the friction factor K is not a constant or a linear function of the gas velocity.

However, that counts for both dilute- and dense phase pneumatic conveying.

Are you indicating that the calculation method, as referred to in Mr Agarwal’s reply #6, for dilute phase also fails?

If this is true, then serious considerations regarding the calculation method have to be made.

Have a nice day

Teus

Dear Teus,

all the friction factor curves I have seen indicate that the friction factor K follows a curve that can be expressed as

K = a * x^(-b) + c

where K is the friction factor and x a number related to the terminal velocity. What physical condition/effect the variable a and the constant c describe I dare not say.

From above equation it is obvious that for increasing x-values (velocities) the K-value approaches the value of the constant c.

Therefore, for high x-values, the K-factor may be considered a constant in a first approximation.

If the K-factor in the calculation method suggested is chosen large enough and the lower velocity limit is clearly defined there can only be an over-estimation of the calculated pressure loss due to friction.

All other pressure loss calculations suggested are only affected by a potentially higher gas density after each step.

As for every theory applied in pneumatic conveying serious consideration is advised as to the limitations and validity range of the calculation model used.

When reading this thread from the start, which is quite tedious and for sure not often done, there are a couple of posts, which reflect above.

Best regards,

Sven ■

Dear Sven,

Analyzing the formula:

K = a * x^(-b) + c

If x=0 then K = infinite

If x>0 then c < K < infinite

The variables a, b and c are probably material dependent.

x is a number related to the terminal velocity.

How x is related to the terminal velocity is unknown.

In addition, how is x influenced by the velocities along the pipeline, which are related to the compressor pressure and pressure drops along the pipeline?

How do we know that we have chosen a K factor high enough to be on the safe side and how far on the safe side and how do we know if we are above the lower velocity limit?

I would say: Too many uncertainties.

In the formula for K, there is no relation to the SLR and Re-number, accounting for the chance of particle collisions (A higher SLR and/or Re-number increases the number of collisions, increasing the energy lost in collisions).

You state:

“If the K-factor in the calculation method suggested is chosen large enough and the lower velocity limit is clearly defined there can only be an over-estimation of the calculated pressure loss due to friction.”

And

“All other pressure loss calculations suggested are only affected by a potentially higher gas density”

The problem now is that the gas density is related to the pressure drop.

If the calculated pressure loss due to friction is over estimated, the gas densities along the pipeline are under estimated.

In the pneumatic conveying calculations, there are so many feedback loops that overall statements are very uncertain at forehand.

Best wishes

Teus ■

Dear Sven,

Analyzing the formula:

K = a * x^(-b) + c

If x=0 then K = infinite

If x>0 then c < K < infinite

The variables a, b and c are probably material dependent.

x is a number related to the terminal velocity.

How x is related to the terminal velocity is unknown.

In addition, how is x influenced by the velocities along the pipeline, which are related to the compressor pressure and pressure drops along the pipeline?

How do we know that we have chosen a K factor high enough to be on the safe side and how far on the safe side and how do we know if we are above the lower velocity limit?

I would say: Too many uncertainties.

In the formula for K, there is no relation to the SLR and Re-number, accounting for the chance of particle collisions (A higher SLR and/or Re-number increases the number of collisions, increasing the energy lost in collisions).

You state:

“If the K-factor in the calculation method suggested is chosen large enough and the lower velocity limit is clearly defined there can only be an over-estimation of the calculated pressure loss due to friction.”

And

“All other pressure loss calculations suggested are only affected by a potentially higher gas density”

The problem now is that the gas density is related to the pressure drop.

If the calculated pressure loss due to friction is over estimated, the gas densities along the pipeline are under estimated.

In the pneumatic conveying calculations, there are so many feedback loops that overall statements are very uncertain at forehand.

Best wishes

Teus ■

Originally Posted by Teus Tuinenburg

Dear Sven,

Analyzing the formula:

K = a * x^(-b) + c

If x=0 then K = infinite

If x>0 then c < K < infinite

The variables a, b and c are probably material dependent.

x is a number related to the terminal velocity.

How x is related to the terminal velocity is unknown.

In addition, how is x influenced by the velocities along the pipeline, which are related to the compressor pressure and pressure drops along the pipeline?

How do we know that we have chosen a K factor high enough to be on the safe side and how far on the safe side and how do we know if we are above the lower velocity limit?

I would say: Too many uncertainties.

In the formula for K, there is no relation to the SLR and Re-number, accounting for the chance of particle collisions (A higher SLR and/or Re-number increases the number of collisions, increasing the energy lost in collisions).

You state:

“If the K-factor in the calculation method suggested is chosen large enough and the lower velocity limit is clearly defined there can only be an over-estimation of the calculated pressure loss due to friction.”

And

“All other pressure loss calculations suggested are only affected by a potentially higher gas density”

The problem now is that the gas density is related to the pressure drop.

If the calculated pressure loss due to friction is over estimated, the gas densities along the pipeline are under estimated.

In the pneumatic conveying calculations, there are so many feedback loops that overall statements are very uncertain at forehand.

Best wishes

Teus

SIR

Plea to answer and support me in move to address teh below concern

1) For existing dense phase conveying system of 45TPH , I have a pressure tank of 120cft . Now since we have to incerase the capacity from 45 to 100TPH , can you help me to guide how to modify the tank from 120CFT to revised defined vessel capacity ie 200CFT

Is there any clue in regard to remove the dish and fabricate another required cylindrical height in vessel along with inlet valve size and weld it to existing one

to comply the new defined capacity 200CFT

Whether this approach is conceivable. I would like to be advised by you for any alternate approach

Thanks for genorosity ■

Originally Posted by Teus Tuinenburg

Dear Sven,

Analyzing the formula:

K = a * x^(-b) + c

If x=0 then K = infinite

If x>0 then c < K < infinite

The variables a, b and c are probably material dependent.

x is a number related to the terminal velocity.

How x is related to the terminal velocity is unknown.

In addition, how is x influenced by the velocities along the pipeline, which are related to the compressor pressure and pressure drops along the pipeline?

How do we know that we have chosen a K factor high enough to be on the safe side and how far on the safe side and how do we know if we are above the lower velocity limit?

I would say: Too many uncertainties.

In the formula for K, there is no relation to the SLR and Re-number, accounting for the chance of particle collisions (A higher SLR and/or Re-number increases the number of collisions, increasing the energy lost in collisions).

You state:

“If the K-factor in the calculation method suggested is chosen large enough and the lower velocity limit is clearly defined there can only be an over-estimation of the calculated pressure loss due to friction.”

And

“All other pressure loss calculations suggested are only affected by a potentially higher gas density”

The problem now is that the gas density is related to the pressure drop.

If the calculated pressure loss due to friction is over estimated, the gas densities along the pipeline are under estimated.

In the pneumatic conveying calculations, there are so many feedback loops that overall statements are very uncertain at forehand.

Best wishes

Teus

SIR

Plea to answer and support me in move to address teh below concern

1) For existing dense phase conveying system of 45TPH , I have a pressure tank of 120cft . Now since we have to incerase the capacity from 45 to 100TPH , can you help me to guide how to modify the tank from 120CFT to revised defined vessel capacity ie 200CFT

Is there any clue in regard to remove the dish and fabricate another required cylindrical height in vessel along with inlet valve size and weld it to existing one

to comply the new defined capacity 200CFT

Whether this approach is conceivable. I would like to be advised by you for any alternate approach

Thanks for genorosity ■

Dear kj,

Modifying a pressure tank is always possible.

However, you have to comply with the local regulations and certifying rules.

In addition, check the changed material flow conditions.

As the capacity will be increased, the outlet pipe size connection might need to be modified too.

An alternative approach is to build a new pressure tank.

Take care

Teus ■

Dear kj,

Modifying a pressure tank is always possible.

However, you have to comply with the local regulations and certifying rules.

In addition, check the changed material flow conditions.

As the capacity will be increased, the outlet pipe size connection might need to be modified too.

An alternative approach is to build a new pressure tank.

Take care

Teus ■

Mr. Agarwal:

Thank you for sending me the article on "Theory and Design of Dilute

Phase Pneumatic Conveying Systems". The method presented is a

practical approach and I highly recommend it to any person seeking

information on the design of dilute phase systems.

---

C. Nihcols ■

Mr. Agarwal:

Thank you for sending me the article on "Theory and Design of Dilute

Phase Pneumatic Conveying Systems". The method presented is a

practical approach and I highly recommend it to any person seeking

information on the design of dilute phase systems.

---

C. Nihcols ■

Mr. Agarwal;

Thanks for sending the dilute phase conveyance design article. It is a good approach and I recommend it to anyone designing a pneumatic conveyance system.

Gale S. ■

Mr. Agarwal;

Thanks for sending the dilute phase conveyance design article. It is a good approach and I recommend it to anyone designing a pneumatic conveyance system.

Gale S. ■

Mr. Agarwal, thank you for your article and for your disposition to clarify the doubts on the friction coefficient. Your method is much more simpler than others in the literature. I wonder what is the range of accuracy in terms of Reynolds number, line diameter, or capacity. What are the limits of your method. When does it start do differ from other calculations ?? ■

Mr. Agarwal, thank you for your article and for your disposition to clarify the doubts on the friction coefficient. Your method is much more simpler than others in the literature. I wonder what is the range of accuracy in terms of Reynolds number, line diameter, or capacity. What are the limits of your method. When does it start do differ from other calculations ?? ■

Dear Mr. Agarwal,

Thank you very much for sending me your paper entitled "Theory and Design of Dilute Phase Pneumatic Conveying Systems". The theory and calculations presented are very useful, and it will be a great addition to other pneumatic conveying design information that I have compiled. It will also be very helpful in my screening and preliminary sizing for dilute phase conveying systems.

Rick G.

IDEA, Inc. ■

Dear Mr. Agarwal,

Thank you very much for sending me your paper entitled "Theory and Design of Dilute Phase Pneumatic Conveying Systems". The theory and calculations presented are very useful, and it will be a great addition to other pneumatic conveying design information that I have compiled. It will also be very helpful in my screening and preliminary sizing for dilute phase conveying systems.

Rick G.

IDEA, Inc. ■

Thank you Mr. Agarwal for sending me the article on "theory and design of dilute phase pneumatic conveying systems".

This article is very usefull in understanding the parameters that influence the design of a dilute phase pneumatic conveying system. It is also helpfull for any beginner in pneumatic conveying system to understand this subject in short timeframe and get going on this. I strongly recommend this article. ■

Thank you Mr. Agarwal for sending me the article on "theory and design of dilute phase pneumatic conveying systems".

This article is very usefull in understanding the parameters that influence the design of a dilute phase pneumatic conveying system. It is also helpfull for any beginner in pneumatic conveying system to understand this subject in short timeframe and get going on this. I strongly recommend this article. ■

Dear Amit

Can you please forward me the copy of the article and the excel file along with it at my id

sahil.g.iit@gmail.com

Thanks ■

Dear Amit

Can you please forward me the copy of the article and the excel file along with it at my id

sahil.g.iit@gmail.com

Thanks ■

Dear Sir,

Can you please help me by sending me a copy of your three articles cited throughout Bulk-Online forum, being:

1) "Theory and Design of Pneumatic Conveying Systems"

2) "Debottlenecking Pneumatic Conveying Systems" and

3) "Product Quality in Pneumatic Conveying"

My email is rajesh.kumar.lurgi@gmail.com

Thank you.

Rajesh



QUOTE=Amrit Agarwal;14426]My article "Theory and Design of Dilute Phase Pneumatic Conveying Systems" was published this month in Powder Handling and Processing magazine. This article gives an easy to use Excel-based calculation method for designing new dilute phase pneumatic conveying systems or for improving the performance of existing conveying systems.

Regards,

Amrit T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services

Email: polypcc@aol.com

Ph and Fax: 304 346 5125[/QUOTE] ■

Dear Sir,

Can you please help me by sending me a copy of your three articles cited throughout Bulk-Online forum, being:

1) "Theory and Design of Pneumatic Conveying Systems"

2) "Debottlenecking Pneumatic Conveying Systems" and

3) "Product Quality in Pneumatic Conveying"

My email is rajesh.kumar.lurgi@gmail.com

Thank you.

Rajesh



QUOTE=Amrit Agarwal;14426]My article "Theory and Design of Dilute Phase Pneumatic Conveying Systems" was published this month in Powder Handling and Processing magazine. This article gives an easy to use Excel-based calculation method for designing new dilute phase pneumatic conveying systems or for improving the performance of existing conveying systems.

Regards,

Amrit T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services

Email: polypcc@aol.com

Ph and Fax: 304 346 5125[/QUOTE] ■

Dear Mr. Agarwal,

In your article "Theory and Design of Dilute Phase Pneumatic Conveying Systems", you have indicated that for pressure systems, we have to start the calculation from the end of conveying line and return to the pick-up point.

If so, then we need to use the final exit conditions like velocity, density, viscosity, pressure, etc., in the section no. 1 of worksheet #3. How to obtain the end conditions in that case.

If my above understanding is wrong, please clarify me.

Also, please let me know whether any other factors need to be considered for dense phase conveying (i,e for higher the solid/air ratio and low velocity).

Thanks in advance.

Thennarasu.

Originally Posted by Amrit Agarwal

My article "Theory and Design of Dilute Phase Pneumatic Conveying Systems" was published this month in Powder Handling and Processing magazine. This article gives an easy to use Excel-based calculation method for designing new dilute phase pneumatic conveying systems or for improving the performance of existing conveying systems.

Regards,

Amrit T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services

Email: polypcc@aol.com

Ph and Fax: 304 346 5125

■

Dear Mr. Agarwal,

In your article "Theory and Design of Dilute Phase Pneumatic Conveying Systems", you have indicated that for pressure systems, we have to start the calculation from the end of conveying line and return to the pick-up point.

If so, then we need to use the final exit conditions like velocity, density, viscosity, pressure, etc., in the section no. 1 of worksheet #3. How to obtain the end conditions in that case.

If my above understanding is wrong, please clarify me.

Also, please let me know whether any other factors need to be considered for dense phase conveying (i,e for higher the solid/air ratio and low velocity).

Thanks in advance.

Thennarasu.

Originally Posted by Amrit Agarwal

My article "Theory and Design of Dilute Phase Pneumatic Conveying Systems" was published this month in Powder Handling and Processing magazine. This article gives an easy to use Excel-based calculation method for designing new dilute phase pneumatic conveying systems or for improving the performance of existing conveying systems.

Regards,

Amrit T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services

Email: polypcc@aol.com

Ph and Fax: 304 346 5125

■

Dear Mr Agarwal,

You state:

Originally Posted by Amrit Agarwal

The air flow will depend on the conveying velocity at the pick-up point.

The pneumatic conveying calculation should start with the air flow at atmospheric conditions at the end of the (pressure) pipeline and results in the pressure at the pickup point.

Thus:

The conveying velocity at the pick-up point and thereby the airflow at the pick-up point, depends on the pressure at the pickup point, which has to be calculated first.

In other words, the calculation result depends on the calculation result and such a calculation can only be solved by an iterative program.

On the other hand, the law of continuity says that the air mass flow at the beginning of a non leaking pipe must be the same as at the end of the same pipe.

Best regards

Teus ■

Dear Mr Agarwal,

You state:

Originally Posted by Amrit Agarwal

The air flow will depend on the conveying velocity at the pick-up point.

The pneumatic conveying calculation should start with the air flow at atmospheric conditions at the end of the (pressure) pipeline and results in the pressure at the pickup point.

Thus:

The conveying velocity at the pick-up point and thereby the airflow at the pick-up point, depends on the pressure at the pickup point, which has to be calculated first.

In other words, the calculation result depends on the calculation result and such a calculation can only be solved by an iterative program.

On the other hand, the law of continuity says that the air mass flow at the beginning of a non leaking pipe must be the same as at the end of the same pipe.

Best regards

Teus ■