Component 136: Emission Display

Specifications

Line connections
1	Logic Inlet (connection to measured stream)
2	Logic Outlet (H = value of calculated maximum dew point)

General User Input Values Physics Used Displays Example

General

Component 136 determines the water dew point as well as several acid dew points from the composition of the stream that is connected through a logic line at port 1. The maximum dew point resulting from the correlations for all liquids involved can be read from a logic outlet at port 2, for instance to serve as an input for a controller unit. The Emission Display enables the calculation of the emissions of various gaseous components based on a user-specified basis for the oxygen and water content of the gas stream under reference conditions.

User Input Values

SO2SO3CONV	SO2 to SO3 conversion (molar ratio of sulfur trioxide formed from the incoming sulfur dioxide)
FH2SO4	Sulfuric acid dew point method Like in Parent Profile (Sub Profile option only) Expression =0: Maximum calculated dew point =1: Weighted dew point
WACDVER	Weight sulfuric acid dew point by Verhoff and Banchero (1974)
WACDZAR	Weight sulfuric acid dew point by ZareNezhad (2009)
WACDHAA	Weight sulfuric acid dew point by Haase
WACDABB	Weight sulfuric acid dew point by ABB
WACDMAR	Weight sulfuric acid dew point by Martin
WACDOKK	Weight sulfuric acid dew point by Okkes (1987)
FNORMO2	Scaling to reference O2 concentration Like in Parent Profile (Sub Profile option only) Expression =0: Keep actual O2 concentration (no scaling) =1: Scale to molar 02 concentration from model settings =2: Scale to molar 02 concentration specified in O2REF =3: Scale to dry molar 02 concentration from model settings =4: Scale to dry molar 02 concentration specified in O2REF =5: Keep actual O2 concentration, scale to dry basis
O2REF	Reference O2 concentration (molar)
FUNIT	Emission concentration unit of measure Like in Parent Profile (Sub Profile option only) Expression =0: Mass per standard volume (according to DIN 1343 at 0°C/32F and 1 atm/1013.25 mbar/14.969 psia) =1: Volume fraction

Result values

ACDEWVER	Sulfuric acid dew point temperature according to Verhoff and Banchero (1974)
ACDEWZAR	Sulfuric acid dew point temperature according to ZareNezhad
ACDEWHAA	Sulfuric acid dew point temperature according to Haase
ACDEWABB	Sulfuric acid dew point temperature according to ABB
ACDEWMAR	Sulfuric acid dew point temperature according to Martin
ACDEWOKK	Sulfuric acid dew point temperature according to Okkes (1987)
ACDEWH2SO4	Sulfuric acid dew point temperature (calculated as per setting FH2SO4)
ACDEWH2SO3	Sulfurous acid dew point temperature
ACDEWHNO3	Nitric acid dew point temperature
ACDEWHCL	Hydrochloric acid dew point temperature
TDEW	Water dew point temperature
ACDEWMAX	Maximum dew point temperature (of all liquids, will be written to enthalpy of logic line at port 2)
M_i	Mass flow of component i (i= CO2, CO, SO2, NO, NO2, N2O, NH3, H2O, HCl)
Y_i	Concentration of component i (i= CO2, CO, SO2, NO, NO2, N2O, NH3, H2O, HCl)

Physics Used

Calculation of Acid Dew Points

The formulas for the calculation of dew points of the various acids are given below, where T denotes the acid dew point temperature in Kelvin, and P denotes the partial pressure of the respective flue gas component in mm Hg (Torr).

Sulphuric acid dew point according to Verhoff and Banchero (1974):

The partial pressure of sulfur trioxide SO3 which is not considered as a stream component in EBSILON is calculated from the user input SO2SO3CONV for the conversion of SO2 to SO3 as a product of this specification value with the mole fraction of sulfur dioxide in the stream and the pressure in the pipe. In the literature values for this conversion rate can be found in the range of 0.1 to 4% depending on the type of fuel, so a value of 4%, in EBSILON was chosen as a safe default value. If the value for SO2SO3CONV is set to zero, the equation for the sulfuric acid dew point is not evaluated and the dew point is set to 0 degrees C in the result, since sulfuric acid cannot be formed in the absence of SO3.

Alternatively, there are five additional equations for the sulfuric acid dew point available in component 136 which are all evaluated based in the composition of the stream connected through the logic line at port 1. These are the equations according to ZareNezhad (2009), Haase, ABB, Martin, and Okkes (1987).

In the settings for the method FH2SO4 the user can select whether the resulting acid dew point (result value ACDEWH2SO4) shall be the maximum of all resulting H2SO4 dew point temperatures, or the weighted average of the dew points that is generated by multiplication of the individual dew point with the weight factors specified by the user. The latter feature can also be used to select an individual equation exclusively by setting its weight factor to 1 and all other weights to zero.

Sulphurous acid dew point according to Yen Hsiung Kiang (1981):

Nitric acid dew point according to Yen Hsiung Kiang (1981):

Hydrochloric acid dew point according to Yen Hsiung Kiang (1981):

In order to expose the maximum calculated dew point for control algorithms in the model during the calculation, the maximum value of all active equations (i.e. for the sulfuric acid dew point the value that has been defined according to method FH2SO4) is written to the enthalpy value of the logic line connected at port 2, which allows for utilizing this value with a defined offset as a target value for a controller for the feed water inlet temperature into the coldest preheater. At the end of the calculation this maximum value is also written to the result value ACDEWMAX.

Emission Calculations

In the emission calculation, the mass fractions of the components carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2) , nitrogen monoxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O), ammonia (NH3), water (H2O), and hydrochloric acid (HCl) are converted to a user-defined unit of measure for concentration (selectable from the method FUNIT) with user-defined reference oxygen concentration (selectable from the method FNORMO2). The reference state for the standard volume for the emission calculations is 0°C (32 F) and 1 atm (1013.25 mbar, 14.696 psia) in accordance with DIN 1343.

Important Notice: Although the units of measure for the result variables Y_i change immediately after a change in the setting for the emission concentration unit of measure (FUNIT), the model MUST be executed to produce the correct emission concentrations, since the values must be re-calculated based on the current settings of the parameters FNORMO2, O2REF, and FUNIT.

Literature references

Verhoff and Banchero (1974)

Verhoff, F.H., and Banchero, J.T., "Predicting dew points of flue gases," Chemical Engineering Progress, Vol. 70 (1974), pp. 71-72

ZareNezhad (2009)

ZareNezhad, B., “New correlation predicts flue gas sulfuric acid dew points”, Oil&Gas Journal, Vol. 107 (35), 60-63, 2009

Okkes (1987)

Okkes, A.G., "Get acid dew point of flue gas," Hydrocarbon Processing, Vol. 7 (1987), pp. 53-55

Yen Hsiung Kiang (1981)

Yen Hsiung Kiang, "Predicting Dew points of Gases", Chemical Engineering Vol. 88, Issue 3 (1981), p. 127

Component Displays

	Display Option 1

Example

Click here >> Component 136 Demo << to load an example.

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