3 replies to this topic

[Huba]

Hi all,

 

I need to calculate the pressure drop for a biogas pipeline. The biogas is produced from a digester plant, so will be saturated with moisture. I assume the moisture will condensate in the pipe run, and will add into the friction losses.

I looked up the Lockhart-Martinelli correlation for gas-liquid flow, which adds a correction factor (theta):

 

DeltaP_2phase = (theta^2) * DeltaP_gasonly

theta^2 = 1 + C/X + 1/X^2

 

X is the Lockhart-Martinelli parameter

X = sqrt (deltaP_liq / deltaP_gas)

 

 

1) To calculate the liquid pressure drop, how can i estimate the condensate phase velocity?

2) Is it possible to simplfiy, by estimating the correction factor? According to Copilot, 1.2 - 1.5 is a good ballpark...

 

Thanks,

[Pilesar]

Pressure? Line size? Line Length? Elevation changes? Fluid quantity? Why not condense and dry before entering pipeline? Why not trap liquid out of the pipeline? Most pipelines of any appreciable length are not completely horizontal. Will liquid just collect and sit in the low spots?

[breizh]

Hi,

Take a look at these links:

moisture in biogas

Avoid moisture problems in your biogas plant. 

 

In addition, you will find a set of equations for different models used for 2 phase flows.

 

Breizh

Attached Files

•  Two_phase_flow M awad.pdf   719.69KB   10 downloads

[carlos infante]

The first thing to consider is to find if the moisture condenses at the process conditions.

 

 

Carlos