Eng​. Unit tab

This section describes properties on the Engineering tab of the Options dialog box.

The Engineering Unit tab sets the default engineering units to save and display.

Note that when global unit settings are modified, users should follow these steps:

• For existing events:

  • Delete the current event data.

  • Reload the data from the source system to ensure it aligns with the new global settings.

• For new event creation:

  • Simply load the data for the new event.

  • Perform reconciliation as needed.

Primary Balance Type

• Select the primary balance type as Volume Balance or Mass Balance. AVEVA Production Accounting DR reconciles the primary balance type for the whole flowsheet while the secondary balance type will only be performed for certain objects depending on the balance type option setting in individual process, node and tank objects.

  Example:

  • The primary balance type is Mass Balance

  • The balance type of tank object TK1 is Volume Balance

  • Other balance objects are set to use Mass and Volume (Both)

    AVEVA Production Accounting reconciles the Mass Balance for most balance points, both Mass and Volume Balance simultaneously for balance points that are configured to do both, and TK1 is reconciled using Volume Balance only.

Engineering Unit

• Select the engineering units of measured and reconciled values when these are saved in the database. AVEVA Production Accounting also uses these definitions when showing the values on the flowsheet or in dialogs. When importing measured data from tags, the data is automatically converted into these default engineering units and then the converted values are saved in the database.

The following engineering units are supported:

• Mass Unit

  "g", "kg", "tonne", "lb", "klb", "ton"

  Use ton instead of tonne as metric ton: If this checkbox is checked, ton is used as metric ton as well as tonne. If this checkbox is unchecked, ton is defined as the short ton equal to 907.18474 kg. The default setting is that this checkbox is checked.

• Liquid Volume Unit

  "cm3", "m3", "k m3", "ml", "l", "kl", "bbl", "kbbl"

• Rate Unit

  "per", "day", "hour", "minute"

• Density Unit

  "SG", "API", "kg/m3", "g/cm3", "kg/l"

• Temperature Unit

  "C", "F", "K"

• Pressure Unit

  "atm", "bar", kg/cm3", "kg/m2", "kPa", "mmHg", "psi"

  Use gauge pressure instead of absolute pressure: If this checkbox is checked, the engineering unit of the pressure value is defined as gauge pressure instead of absolute pressure and one atmospheric pressure is added to the pressure value in calculating the flow compensation or enthalpy.

• Component Unit

  "wt%", "vol%", "mol%", "wtfrac", "volfrac", "molfrac"

• Heating Value Unit

  "cal/g", "cal/kg", "kcal/kg", "J/g", "kJ/kg", "Btu/lb", "Btu/kg"

• FOE Value Unit

  "l/Nm3", "l/scf", "bbl/Nm3", "bbl/scf", "m3/Nm3", "m3/scf"

• Length Unit

  "m", "cm", "mm", "ft", "in"

• Gas Volume Unit

  "scf", "k scf", "Nm3", "k Nm3", "Sm3", "k Sm3"

• SP Enthalpy Unit

  "cal/g", "cal/kg", "kcal/kg", "J/g", "kJ/kg", "Btu/lb" , “Btu/kg”

• Enthalpy Unit

  Based on selection of specific enthalpy Unit Enthalpy Unit get reflected.

  • Enthalpy Unit is {kJ, MJ, GJ} – if Specific Enthalpy unit is { kJ/kg or J/g}

  • Enthalpy Unit is {Kcal, Mcal, Gcal} – if Specific Enthalpy unit is {cal/g, cal/Kg, Kcal/Kg}

  • Enthalpy Unit is {BTU, MMBTU} - if Specific Enthalpy unit is {BTU/lb, BTU/kg}

    Note:

    Mass Unit for calculating the Enthalpy when specific enthalpy is Btu/lb should be {lb or klb}

    Mass Unit for calculating the Enthalpy when specific enthalpy is {cal/g, cal/kg, kcal/kg, J/g, kJ/kg, Btu/kg} should be {kg or g or tonne or ton}

    The above mentioned UOM combinations will give the exact calculated value of enthalpy based on the selected UOM.

Composition Unit

For more information, see Composition Unit functions.

• Main Composition Unit: When you run tracking, if two different composition units are tracked, this is the main composition unit.

• Use alternative composition unit: If this checkbox is selected, two different composition units are calculated and vice versa. The product composition is tracked with the alternative composition unit as well as the main composition unit.

Heating value and water density

• Fuel Oil Heating Value: This is used to convert gas flow volumes into fuel oil equivalent volumes. It is slightly different for each plant site. You should input a value to meet your plant site’s specifications.

• Water Density at Reference Temperature: The water density at reference temperature (60 F) is 0.9991266 kg/l but most companies use 1 for the sake of convenience.

• Eng. Unit for New Movement Stream: If movement data have no engineering unit, the engineering unit defined here is used when getting these movement data.