HYDRAULIC ANALYSIS CALCULATION FOR ASH SLURRY PIPELINE

HYDRAULIC ANALYSIS CALCULATION FOR ASH SLURRY PIPELINE

The velocity of slurry in pipelines shall be in the range 1.8 m/s to 2.5m/s to avoid increasing the wear rate of the pipeline (if operating velocity above 2.5m/s) and risks of settling out and causing a blockage inside pipeline (if operating velocity below 1.8m/s). This slurry is non-Newtonian fluid so that the formula of Durand equation will be applied to calculate the friction loss of slurry.

The difference i - i_w represents an increase in pressure drop due to the presence of solids in the slurry. The effect of particle size on slurry pressure drop is accounted for by the inclusion of the drag coefficient C_D.

In most industrial applications, the particle size is not uniform, so the equation above can be written as follows:

Step 1: Calculation C_DRe_w² based on input data.

C_DRe_w² = ρ_l(4gd³(ρ_s - ρ_l)/(3µ²g_c²

Whereas:

C_D – Drag coefficient

d – Particle diameter (m)

g – Acceleration due to gravity (9.81 m/s²)

ρ_l – Density of liquid (kg/m³)

ρ_s – Density of solid particle (kg/m³)

Re_w = d ρ_l w₀/(gµ)

w₀ – settling velocity (m/s)

µ - viscosity of liquid (kg.s/m).

Step 2: Find the drag coefficient of particles of individual size fraction based on result of step 1

Source: Piping handbook, seventh edition.

Step 3: Calculation of friction loss of slurry

Calculation follows below equation:

i_w – friction loss for water (mH₂O/m) were calculated by software.

i – Friction loss for slurry

C_vi – volume fraction of solid having size d_i

C_Di – Drag coefficient of particle having size d_i

N – Total number of size fraction into which given particle size distribution is divided.

Calculation file: Download