Pulsater555
Petroleum
Hello All,
I have seen the term used "average mean absolute pressure" throughout API 618, 7.9.4.5.2 Design Criteria. Are they just referring to the mean (or average) pressure to be seen across a specific stage? Example below:
Pressure in pisa, the numbers are arbitrary.
Stage 1 Ps Pd
Case 1 5 50
Case 2 8 55
Case 3 10 65
The mean pressure for Stage 1 Ps would be 7.666 psia
When looking at the Maximum Allowable Pressure drop formula across pulsation dampening devices it states that the pressure drop shall not exceed 0.25% of the average line pressure, or the value determined by Equation 13, which ever is higher.
ΔP = 1.67 * ((R-1)/R)%
ΔP = is the maximum pressure drop based on steady flow through a pulsation suppression device expressed as a percentage of mean absolute line pressure at the inlet of a device;
R = is the stage pressure ratio
So, does this mean that my allowable pressure drop ratio is as follows?
Case 1, R=10
Case 2, R=6.875
Case 3, R= 6.5
Case 1, Stage 1 Ps, ΔP= 1.67 * ((10-1)/10)% * 7.666 = 0.1151 psia
Case 2, Stage 1 Ps, ΔP= 1.67 * ((6.875-1)/6.875)% * 7.666 = 0.1094 psia
Case 3, Stage 1 Ps, ΔP= 1.67 * ((6.5-1)/6.5)% * 7.666 = 0.1083 pisa
I know there is a note stating that there is a lower % limit and a multiplier for full flow but I just wanted to make sure that I understand this portion correctly.
I have seen the term used "average mean absolute pressure" throughout API 618, 7.9.4.5.2 Design Criteria. Are they just referring to the mean (or average) pressure to be seen across a specific stage? Example below:
Pressure in pisa, the numbers are arbitrary.
Stage 1 Ps Pd
Case 1 5 50
Case 2 8 55
Case 3 10 65
The mean pressure for Stage 1 Ps would be 7.666 psia
When looking at the Maximum Allowable Pressure drop formula across pulsation dampening devices it states that the pressure drop shall not exceed 0.25% of the average line pressure, or the value determined by Equation 13, which ever is higher.
ΔP = 1.67 * ((R-1)/R)%
ΔP = is the maximum pressure drop based on steady flow through a pulsation suppression device expressed as a percentage of mean absolute line pressure at the inlet of a device;
R = is the stage pressure ratio
So, does this mean that my allowable pressure drop ratio is as follows?
Case 1, R=10
Case 2, R=6.875
Case 3, R= 6.5
Case 1, Stage 1 Ps, ΔP= 1.67 * ((10-1)/10)% * 7.666 = 0.1151 psia
Case 2, Stage 1 Ps, ΔP= 1.67 * ((6.875-1)/6.875)% * 7.666 = 0.1094 psia
Case 3, Stage 1 Ps, ΔP= 1.67 * ((6.5-1)/6.5)% * 7.666 = 0.1083 pisa
I know there is a note stating that there is a lower % limit and a multiplier for full flow but I just wanted to make sure that I understand this portion correctly.
