2 replies to this topic

[AthlonX2]

Hi All,

 

I'm in the midst of checking mass balance which involve some equation on density estimation at flowing temperature. Currently, I'm using this equation for the density estimation:

 

ρ_{@flowing T} = [ρ_@o15C^{^2} - 0.0011(Flowing Temperature -15)]^{^0.5}

 

On top of that, I also found another formula for the density estimation based on Revised Petroleum Measurement Tables (IP200, ASTM D1250,API 2540 and ISO R91) as below:

 

ρ_T / ρ₁₅ = exp ( -α₁₅ Δt ( 1 + 0.8 α₁₅ ΔT) )

 

where:

ρ_T = Density at line temperature t°C (kg/m3)

ρ₁₅ = Density at base temperature 15°C (kg/m3)

ΔT= ( t -15 )°C (i.e., t - base temperature)

α₁₅ = Tangent thermal expansion coefficient per °C at base temperature 15°C

 

α₁₅ = (K₀ + K₁ρ₁₅) / (ρ₁₅)^{^2}

 

Reference: Emerson Micro Motion® 7826/7828 Insertion Liquid Density Meters:Appendix B -Calculated Parameters (Advanced version)

 

Upon checking between these 2 formulas, the difference is quite significance whereas the first formula is giving higher values than the 2nd formula, which difference around 2% to 11%.

 

My queries are:

 

i) I couldnt trace the origin of the first formula, thus appreciate if anyone can help me to share the formula origin, if any.

 

ii) Which formula is the best recommended for mass balance by considering it is empirically more accurate?

 

iii) Is there any other recommended best practice  formula used for the density estimation?

 

Thanks a lot for assistance... 

[breizh]

hi ,

-You may consider the estimation methods available in this document (CHEMCAD ) .

- Using your favorite search engine you could probably find other correlations .

- Another resource could be Perry's Chemical engineers' handbook

Good luck

Breizh

 

[AthlonX2]

Hi Mr breizh,

 

Thanks a lot for your sharing...Really appreciate it!