Re: Pneumatic Conveying Calculation As An Iterative Algorithm
Originally Posted by Teus Tuinenburg
The given input parameters are then capacity and air mass flow.
To calculate the pressure drop, the pneumatic conveying resistance must be calculated.
An extra given parameter is the end pressure of the system (In most cases atmospheric, but in specific cases, the end pressure is higher, f.i. a blast furnace or lower, f.i. boiler)
The start situation is the as follows:
Input:
- Ambient pressure
- Pipe geometry
- Compressor volume (gas mass flow)
- End pressure
- Capacity
- Additional resistances s.a. clean air pipe, bends, silencers, intake nozzles and filters. (ignored in this consideration)
From the selected capacity and the selected air mass flow, the solid loading ration is calculated.
To calculate the pressure drop, we can use the general resistance formula:
∆pconveying=function1(velocity(gas-material) )^2
Also:
velocity(gas-material) = function2(∆plocal+pambient )
Resulting in:
∆pconveying = function1(function2(∆plocal+pambient ))^2
In this equation, the conveying pressure is dependent on the sum of the local pressures along the pipeline, which are themselves dependent on the conveying pressure, which has to be calculated.
The conveying pressure and the sum of the local pressures can not be isolated to one side of the equation.
Also, the condition
∆p-compressor -∆p(conveying-calculated) = pambient
must be fulfilled.
The only way to solve the calculation is an iterative algorithm with a root finding algorithm.
Hi Mr. Teus,
I am currently studying on calculation for pneumatic conveying system (pipe size, sizing of fan) and learn more in-depth about pneumatic conveying system. At current moment, I am studying all this with the handbook from David Mills, and from internets. The current method that i am using is through guessing of pressure drops and from there using iterative method. However, I will need a graph which i think is plotted or derived from a test rig. For different material, it will generate different graphs due to the different characteristic of the materials.
Do you have any source/handbook that can guide me in my fundamental? I wish to generate my own spreadsheet and really understand how the calculation works.
Also, I noticed your yarca.nl website. I would like to know how your software works and are you actually selling the software?
Regards,
Marcus ■
Re: Pneumatic Conveying Calculation As An Iterative Algorithm
Dear Mr. Marcus,
The current method that I am using is through guessing of pressure drops and from there using iterative method.
That you are using an iterative method, based on an educated guess (whether that guess is the pressure drop or the capacity) is the only correct method.
The iterative method is required to match the input values with the output values.
For a pneumatic conveying calculation, at least 2 things are needed:
1-A set of formulas. (Derived from physic laws and mathematics)
2-The material pneumatic conveying properties. (Derived from field tests and/or laboratory tests)
For a reliable calculation, the material pneumatic conveying properties must relate to the used formulas and calculation algorithm.
Using lab test as a reference, a scaling problem to a real installation is introduced, causing uncertainties.
The many companies in the pneumatic conveying world all have their own calculation method, based on the air only pressure drop multiplied (or air only pressure head) with a K-factor, accounting for the presence of a certain material.
For commercial reasons, these calculation methods are sealed from publishing, to protect the business.
On the internet, many articles and theses can be found, describing what you are looking for.
Although, I must admit that these articles do not give a straightforward path to build a spreadsheet.
Understandable, when you realize how much work that is.
The Yarca software is not available on the market. ■
Teus
Pneumatic conveying calculation as an iterative algorithm
In general, a pneumatic conveying system calculation must result in a calculated pressure drop at a given capacity for a specific pipeline routing and selected compressor.
The given input parameters are then capacity and air mass flow.
To calculate the pressure drop, the pneumatic conveying resistance must be calculated.
An extra given parameter is the end pressure of the system (In most cases atmospheric, but in specific cases, the end pressure is higher, f.i. a blast furnace or lower, f.i. boiler)
The start situation is the as follows:
Input:
- Ambient pressure
- Pipe geometry
- Compressor volume (gas mass flow)
- End pressure
- Capacity
- Additional resistances s.a. clean air pipe, bends, silencers, intake nozzles and filters. (ignored in this consideration)
From the selected capacity and the selected air mass flow, the solid loading ration is calculated.
To calculate the pressure drop, we can use the general resistance formula:
∆pconveying=function1(velocity(gas-material) )^2
Also:
velocity(gas-material) = function2(∆plocal+pambient )
Resulting in:
∆pconveying = function1(function2(∆plocal+pambient ))^2
In this equation, the conveying pressure is dependent on the sum of the local pressures along the pipeline, which are themselves dependent on the conveying pressure, which has to be calculated.
The conveying pressure and the sum of the local pressures can not be isolated to one side of the equation.
Also, the condition
∆p-compressor -∆p(conveying-calculated) = pambient
must be fulfilled.
The only way to solve the calculation is an iterative algorithm with a root finding algorithm. ■
Teus