calculate the z factor automatically

[khalid khalid1111]

How do I calculate the z factor automatically by using Hall-Yarborogh equation without changing (Y) every time to reach F=0 ?
if any body know .please answer me.

Thank you very much

khalid
INPUT DATA:
T 68 oF
p 1000 psia
SGFG 0.5 air=1

CALCULATE CRITICAL AND REDUCED TEMPERATURE AND PRESSURE:
Tpc=169.0+314.0*SGFG Ppc=708.75-57.5*SGFG
Tpr=(T+460.0)/Tpc t=1/Tpr
Ppr=p/Ppc


CALCULATE TEMPERATURE DEPENDENT TERMS:
A=0.06125*t*EXP(-1.2*(1.-t**2)
B=t*(14.76-9.76*t+4.58*t*t)
C=t*(90.7-242.2*t+42.4*t*t)
D=2.18+2.82*t


CALCULATE REDUCED DENSITY Y
Y = ASSUMED 0.324006985
F=-A*Ppr+(Y+Y*Y+Y**3-Y**4)/(1.-Y)**3-B*Y*Y+C*Y**D
USE goal seek MACRO SOLUTION: goal seek (F) = 0 by changing (Y)

CALCULATE Z-FACTOR:

Z=A*Ppr/Y

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[Harlan Grove]

How do I calculate the z factor automatically by using Hall-Yarborogh
equation without changing (Y) every time to reach F=0 ? ....
INPUT DATA:
T 68 oF
p 1000 psia
SGFG 0.5 air=1

Following formulas changed to Excel operators.

CALCULATE CRITICAL AND REDUCED TEMPERATURE AND PRESSURE:
Tpc = 169.0 + 314.0 * SGFG
Ppc = 708.75 - 57.5 * SGFG
Tpr = (T + 460.0) / Tpc
t = 1 / Tpr
Ppr = p / Ppc

CALCULATE TEMPERATURE DEPENDENT TERMS:
A = 0.06125 * t * EXP(-1.2 * (1 - t^2))

I'm assuming you left off the final right parenthesis above.

B = t * (14.76 - 9.76 * t + 4.58 * t^2)
C = t * (90.7 - 242.2 * t + 42.4 * t^2)
D = 2.18 + 2.82 * t

CALCULATE REDUCED DENSITY Y
Y = ASSUMED 0.324006985
F = -A * Ppr + (Y + Y^2 + Y^3 - Y^4) / (1 - Y)^3 - B * Y^2 + C * Y^D

USE goal seek MACRO SOLUTION: goal seek (F) = 0 by changing (Y)

CALCULATE Z-FACTOR:

Z = A * Ppr / Y

So the desired Y value makes F(Y) = 0.

0 = -A * Ppr + (Y + Y^2 + Y^3 - Y^4) / (1 - Y)^3 - B * Y^2 + C * Y^D

A * Ppr = (Y + Y^2 + Y^3 - Y^4) / (1 - Y)^3 - B * Y^2 + C * Y^D


There's no analytical/algebraic solution for Y in terms of A, Ppr, B, C, and
D. So you MUST ALWAYS vary Y in order to produce F(Y) = 0 in order to solve
for Z.

 

[Dana DeLouis]

Hi. I may be wrong, but this site suggest the following:

http://www.peteng.com/jmm/zfc02.html

A=0.06125*t*EXP(-1.2*(1.-t**2)

Looks to me like temp. variable 'A should be:

A =-.06125*Ppr*t*Exp(-1.2*(1-t)^2)

The T (Temperature) said that it's valid only for T >100 (vs your 68)

A few other small differences.

Again, I'm not familiar with the topic to know if the above applies.

 

[joeu2004]

How do I calculate the z factor automatically by using
Hall-Yarborogh equation without changing (Y) every time
to reach F=0 ?

As I noted in the other threads on the same subject that you
started ....

This relates to a high-specialized area of engineering. If you
posted
the formulas here, __maybe__ someone could help you. But I suspect
this requires more knowledge of the science than of Excel. You might
get some "hint" by looking at z.xls that apparently comes with the
book "Petroleum Production Engineering" by Boyun Guo (2007).

 

[Harlan Grove]

This relates to a high-specialized area of engineering. If you
posted the formulas here, __maybe__ someone could help you. . . .

You didn't notice the OP did post formulas?

But I suspect this requires more knowledge of the science than of Excel.

....

So?