Commissioning FLOWSIC100 Flare-XT
FLOWSIC100 Flare-XT · Operating Instructions · 8023761/V1-0/2020-10 · © SICK Engineering GmbH
135
7.5.7.2
Compressibility
In addition to the flow rate, the measured pressure and temperature and the
compressibility K under standard conditions and operating conditions are also required for
the calculation of a volume flow at base conditions.
Fig. 90
Calculation of volume flow at base conditions
For applications < 5 bar, compressibility can always be approximated sufficiently well with
value 1. In applications with higher process pressures either constant values for the
compressibilities can be configured in the Setup wizard or calculated with a suitable
algorithm.
7.5.8
Application
CO
2
calculation
In flare gas applications, unlike CEMS measurements, CO
2
emissions cannot be measured
directly because the CO
2
is only created directly at the flare during combustion. Typically,
the CO
2
emissions are determined according to a calculation model, which has also been
directly implemented in the FLOWSIC100 Flare-XT. Since the measuring device provides an
important calculation variable, the mass flow, the calculation of CO
2
emissions can take
place directly in the FLOWSIC100 Flare-XT.
The oxidation factor is an installation-dependent fixed value and describes the combustion
quality and is provided by the flare manufacturer.
The emission factor describes the flare gas. As there is normally no precise information on
the composition of the specific flare gas, an application-dependent fixed value is normally
used.
But however, as the FLOWSIC100 Flare-XT can compensate for the components CO
2
, N
2
and H
2
O which contribute to the generation of CO
2
, the measuring system can calculate an
emission factor. This allows direct calculation of the real, lower CO
2
emissions.
Fig. 91
Formula for calculating the CO
2
emission
Qsc Qac
Pac
Psc
----------
Tsc
Tac
--------- 1
K
----
=
Qac = Operating volume flow
Qsc = Volume flow at base conditions
Pac = Pressure at operating conditions
Psc = Pressure at base conditions
Tac = Temperature at operating conditions
Tsc = Temperature at base conditions
K = Compressibility
emissionCO
2
eCO
2
MFlow OxydationFactor
=
eCO2 =Emission factor CO
2
MFlow = mass flow rate
OxydationFactor = factor for completeness of combustion (ideal = 1; typically 0.94)
Source: Reporting of greenhouse gas emissions under Directive 2003/87/EC of the European Parliament and of the Council
