Logo Studenta

Aga7 - Cesar Delgado

Vista previa del material en texto

AGA7
American Gas Association Report No.. 7 Module
Page AGA7-1
ACCOL II Reference Manual
The AGA7 Module calculates the base volume rate (Qb) as described in
the American Gas Association Report No. 7, reference catalog No.
XQ0508. This module computes the base volume rate by implementing
the equations from Section 6, Volumetric Flow Measurement, as well
as the equations from Section 7, Mass Flow Measurement. The spe-
cific computation method used is selected by the use of module termi-
nals.
Flow rate of the gas is obtained from a HSCOUNT (High Speed
Counter) or LSCOUNT (Low Speed Counter) Module which is typi-
cally measured by a turbine flowmeter, positive displacement meter,
or vortex shedding meter.
❏ Module Terminals
FLOW_SWITCH Default: OFF (Equation A determines base
volume flow rate)
Format: Logical signal
Input/Output: Input
if this terminal is OFF, the output flow rate will be in Volume units
(Equation A); if this terminal is ON, the output flow rate will be in
Mass units (Equation B). Equations A and B are described later,
under 'Module Equations'.
FLOW_TEMP
FLOW_PRESS
FLOW_SWITCH
DENS_SWITCH
RATE
BASE_TEMP
BASE_PRESS
FPV_IN
ADJ_PRESS
FLOW_DENS
BASE_DENS
SPEC_GRAV
GRAV_TEMP
CALIB_FACTR
SPAN
OUTPUT7
GRAV_PRESS
AGA7
ACCOL II Reference Manual
Page AGA7-2
AGA7
American Gas Association Report No.. 7 Module
ACCOL II Reference Manual
Page AGA7-2
AGA7
American Gas Association Report No.. 7 Module
DENS_SWITCH Default: OFF (Equation C determines base
density)
Format: Logical signal
Input/Output: Input
if this terminal is wired, and OFF, it specifies that a densitometer is
supplying both Flowing Density (Df) and Base Density (Db). The Df and
Db values are specified by the values on the FLOW_DENS and
BASE_DENS terminals.
If this terminal is ON, it specifies that a Gravitometer is used, and
that the value of D
b
 will be calculated using Equation C, and the
values on the SPEC_GRAV, GRAV_TEMP, and GRAV_PRESS termi-
nals. The calculated value of D
b
 will then be used in Equation B, along
with the FLOW_DENS value.
FLOW_TEMP (T
f
) Default: 600F
Format: Analog signal or constant
Input/Output: Input
represents the temperature of the flowing gas in degrees F.
FLOW_PRESS (Pf) Default: None, entry required when
FLOW_SWITCH is OFF
Format: Analog signal or constant
Input/Output: Input
is the static gauge pressure of the flowing gas measured in psig. If
Equation A is selected via the FLOW_SWITCH and this terminal is
not wired, the OUTPUT will not be updated.
DENS_SWITCH Default: OFF (Equation C determines base
density)
Format: Logical signal
Input/Output: Input
if this terminal is wired, and OFF, it specifies that a densitometer is
supplying both Flowing Density (Df) and Base Density (Db). The Df and
Db values are specified by the values on the FLOW_DENS and
BASE_DENS terminals.
If this terminal is ON, it specifies that a Gravitometer is used, and
that the value of D
b
 will be calculated using Equation C, and the
values on the SPEC_GRAV, GRAV_TEMP, and GRAV_PRESS termi-
nals. The calculated value of D
b
 will then be used in Equation B, along
with the FLOW_DENS value.
FLOW_TEMP (T
f
) Default: 600F
Format: Analog signal or constant
Input/Output: Input
represents the temperature of the flowing gas in degrees F.
FLOW_PRESS (Pf) Default: None, entry required when
FLOW_SWITCH is OFF
Format: Analog signal or constant
Input/Output: Input
is the static gauge pressure of the flowing gas measured in psig. If
Equation A is selected via the FLOW_SWITCH and this terminal is
not wired, the OUTPUT will not be updated.
AGA7
American Gas Association Report No.. 7 Module
Page AGA7-3
ACCOL II Reference Manual
RATE (Qf) Default: None, entry required or else
OUTPUT is not updated.
Format: Analog signal or constant
Input/Output: Input
is the uncorrected gas flow (either rate or volume in cu.ft./hr.) as
measured via the HSCOUNT Module (High Speed Counter) or
LSCOUNT Module (Low Speed Counter).
BASE_TEMP (Tb) Default: 60
0F
Format: Analog signal or constant
Input/Output: Input
is the contract base temperature in degrees F.
BASE_PRESS (P
b
) Default: 14.73
Format: Analog signal or constant
Input/Output: Input
is the contract base pressure (psia).
FPV_IN (Fpv) Default: 1.0
Format: Analog signal or constant
Input/Output: Input
is an output signal from the FPV Module.
ADJ_PRESS (Pa) Default: 14.73
Format: Analog signal or constant
Input/Output: Input
is the atmospheric pressure (that is, the barometric pressure) at the
site and is added to the gauge pressure to produce absolute pressure.
ACCOL II Reference Manual
Page AGA7-4
AGA7
American Gas Association Report No.. 7 Module
ACCOL II Reference Manual
Page AGA7-4
AGA7
American Gas Association Report No.. 7 Module
FLOW_DENS (Df) Default: 0.045923 lb/cu.ft. (based on a
specific gravity of 0.6, a tempera-
ture of 600F, a pressure of 14.7 psi,
and a supercompressibility factor
of 1.0.)
Format: Analog signal or constant
Input/Output: Input
is the density of the flowing gas as measured by a densitometer.
BASE_DENS (D
b
) Default: 0.045923 lb/cu.ft. (based on a
specific gravity of 0.6, 600F tem-
perature, 14.7 psi pressure, and a
supercompressibility factor of 1.0.)
Format: Analog signal or constant
Input/Output: Input
is the contract base density as measured via a densitometer.
SPEC_GRAV (SG) Default: 0.6
Format: Analog signal or constant
Input/Output: Input
is the specific gravity of the gas as measured by a gravitometer.
GRAV_TEMP (Tg) Default: 60
0 F
Format: Analog signal or constant
Input/Output: Input
is the temperature at the gravitometer in degrees F.
FLOW_DENS (Df) Default: 0.045923 lb/cu.ft. (based on a
specific gravity of 0.6, a tempera-
ture of 600F, a pressure of 14.7 psi,
and a supercompressibility factor
of 1.0.)
Format: Analog signal or constant
Input/Output: Input
is the density of the flowing gas as measured by a densitometer.
BASE_DENS (D
b
) Default: 0.045923 lb/cu.ft. (based on a
specific gravity of 0.6, 600F tem-
perature, 14.7 psi pressure, and a
supercompressibility factor of 1.0.)
Format: Analog signal or constant
Input/Output: Input
is the contract base density as measured via a densitometer.
SPEC_GRAV (SG) Default: 0.6
Format: Analog signal or constant
Input/Output: Input
is the specific gravity of the gas as measured by a gravitometer.
GRAV_TEMP (Tg) Default: 60
0 F
Format: Analog signal or constant
Input/Output: Input
is the temperature at the gravitometer in degrees F.
AGA7
American Gas Association Report No.. 7 Module
Page AGA7-5
ACCOL II Reference Manual
GRAV_PRESS (Pg) Default: 14.73
Format: Analog signal or constant
Input/Output: Input
is the absolute pressure (psia) at the gravitometer.
CALIB_FACTR (C) Default: 1.0
Format: Analog signal or constant
Input/Output: Input
is an optional calibration factor. This factor is used to correct known
variations in the measuring equipment.
SPAN (K) Default: 1.0
Format: Analog signal or constant
Input/Output: Input
is a scale factor to adjust the OUTPUT to the desired units.
OUTPUT (Qb) Default: None
Format: Analog signal
Input/Output: Output
is the calculated flow rate at base conditions. The units are in MSCFH
(thousands of standard cubic feet per hour) unless modified by the
SPAN terminal.
ACCOL II Reference Manual
Page AGA7-6
AGA7
American Gas Association Report No.. 7 Module
ACCOL II Reference Manual
Page AGA7-6
AGA7
American Gas Association Report No.. 7 Module
❏ Module Equations
The following equation, for base volume rate, is taken from Section 6,
Volumetric Flow Measurement:
 Qf Pf + Pa 519.67
Qb = C * K * * * *
1000 Pb Tf + 459.67
(Tb + 459.67)
* Fpv
2 Equation A
 519.67
where:
Qb = Calculated flow rate at base conditions (output in MSCFH)
C = Calibration factor
K = Span scaling factor
Qf = Flow rate at flowing conditions (cubic feet per hour)
Pf = Static gauge pressure psig
Pa = Atmospheric pressure psia
Pb = Base pressure in psia
Tf = Flowing temperature indegrees F
Tb = Base temperature in degrees F
Fpv = Supercompressibility factor
The following equation, for base volume rate, is taken from Section 7,
Mass Flow Measurement:
 Qf Df
Qb = C * K * * Equation B
1000 Db
where all operands are the same as the previous equation except for:
Df = Density of flowing gas as measured by a densitometer
Db = Base density as measured by a densitometer or calculated by
 Equation C.
❏ Module Equations
The following equation, for base volume rate, is taken from Section 6,
Volumetric Flow Measurement:
 Qf Pf + Pa 519.67
Qb = C * K * * * *
1000 Pb Tf + 459.67
(Tb + 459.67)
* Fpv
2 Equation A
 519.67
where:
Qb = Calculated flow rate at base conditions (output in MSCFH)
C = Calibration factor
K = Span scaling factor
Qf = Flow rate at flowing conditions (cubic feet per hour)
Pf = Static gauge pressure psig
Pa = Atmospheric pressure psia
Pb = Base pressure in psia
Tf = Flowing temperature in degrees F
Tb = Base temperature in degrees F
Fpv = Supercompressibility factor
The following equation, for base volume rate, is taken from Section 7,
Mass Flow Measurement:
 Qf Df
Qb = C * K * * Equation B
1000 Db
where all operands are the same as the previous equation except for:
Df = Density of flowing gas as measured by a densitometer
Db = Base density as measured by a densitometer or calculated by
 Equation C.
AGA7
American Gas Association Report No.. 7 Module
Page AGA7-7
ACCOL II Reference Manual
Gravitometer temperature and pressure are used to determine the
base density (Db) in the following computation (Equation C):
 Pg 492
Db = 0.08073 * * * SG * Fpv
2 Equation C
14.7 Tg + 459.67
where:
Pg = Absolute pressure (psia) at gravitometer
Tg = Temperature (in degrees F) at gravitometer
SG = Specific gravity as measured by gravitometer
Fpv = Supercompressibility factor at Pg and Tg
Return to the Table of Contents
Return to the List of Manuals

Otros materiales

Materiales relacionados

11 pag.
Aga3 - Cesar Delgado

User badge image

Desafio PASSEI DIRETO

202 pag.
AGA 8 1994 - Cesar Delgado

User badge image

Desafio PASSEI DIRETO

72 pag.
API MPMS 20 1 - Cesar Delgado

User badge image

Desafio PASSEI DIRETO