Sawsan311
Chemical
- Jun 21, 2019
- 303
Dear All,
I would like your views on thefollowing:
- the optimum pipe roughness to be considered for the pressure drop calculations for flare system hydraulics. Most of the design practices consider a roughness equivalent to corroded carbon steel pipe since a conservative approach is required for the critical flare lines experiencing high velocities driven by the low pressure compressible vapor flow as well as the fact that flare lines shall be designed safely enough to minimize/eliminate its replacement in case of any issue associated with high vibration (due to undersizing) or corrosion.
- API 521 considers the use of the isothermal/adiabatic flow equations for the compressible vapor flow hydraulic calculations of flare lines. However, section 5.4.4 also states that there can be options to consider the heat transfer with the ambient for the hydraulic calculations. Do you think that isothermal /adiabatic flow hydraulic equations shall be used with no credit for heat transfer between the flare line and the ambient since the relieved vapor would have a high velocity with strong forced convection heat transfer dominating the free convection with the atmosphere (in addition to the low heat capacity of the relieved vapor and hence small changes in temperature)??
Appreciate your views?
I would like your views on thefollowing:
- the optimum pipe roughness to be considered for the pressure drop calculations for flare system hydraulics. Most of the design practices consider a roughness equivalent to corroded carbon steel pipe since a conservative approach is required for the critical flare lines experiencing high velocities driven by the low pressure compressible vapor flow as well as the fact that flare lines shall be designed safely enough to minimize/eliminate its replacement in case of any issue associated with high vibration (due to undersizing) or corrosion.
- API 521 considers the use of the isothermal/adiabatic flow equations for the compressible vapor flow hydraulic calculations of flare lines. However, section 5.4.4 also states that there can be options to consider the heat transfer with the ambient for the hydraulic calculations. Do you think that isothermal /adiabatic flow hydraulic equations shall be used with no credit for heat transfer between the flare line and the ambient since the relieved vapor would have a high velocity with strong forced convection heat transfer dominating the free convection with the atmosphere (in addition to the low heat capacity of the relieved vapor and hence small changes in temperature)??
Appreciate your views?