DESIGN

Aux(2) Tab

This tab is for selection and input of the design conditions for Auxiliary Steam(2) and Auxiliary Water of Design Heat Balance.   This tab also includes whether to "Subtract Aux. Steam/Water Heat Output from Heat Input in Heat Rate Calculation".

Auxiliary steam is the steam supplied to an external user out of turbine cycle.   Two auxiliary steams are provided.

Auxiliary steam is assumed to be returned as condensate to the turbine cycle after use, and the flow not returned as condensate is assumed to be supplemented as condenser make-up water to the turbine cycle.

Auxiliary water is the water supplied to an external user out of turbine cycle.   The users of auxiliary water is categorized into two.  One is the attemperators of the boiler that supplies steam to the turbine cycle, i.e. superheater attemperator and reheater attemperator.   The other is real external user out of turbine cycle.   Difference of the two is whether the supply flow is returned to the turbine cycle as it is.   The supply flow to boiler attemperators returns to the turbine cycle as it is, so that make-up water supplement to the turbine cycle is not required.   On the other hand, the real external user requires make-up water to the condenser.

 

 

Aux. Steam(2) Supply to check box --------------------------------------------------------------------------------------------

To select whether the second auxiliary steam is supplied or not.

User may input the title of the second auxiliary steam in the text box beside, which shall be written in text output.

 

Steam Supply Source combo box

 To select the steam source of Aux. Steam(2).   Selection list includes main steam line, cold reheat line and LP crossover line as well as the bleeding lines for all feed water heaters.

 

Condensate Receiver combo box

 To select the place to receive the return condensate of Aux. Steam(2).   It includes condenser and all feed water heaters.

 

Steam Supply Flow Rate text box

To input flow rate of Aux. Steam(2) to be supplied to an external user.

 

Condensate Return Ratio text box

To input the condensate return ratio of Aux. Steam(2).   The flow not returned as condensate is assumed to be supplemented as condenser make-up water to the turbine cycle.

 

Condensate Return Temperature text box

To input the condensate return temperature of Aux. Steam(2).    It is assumed that the enthalpy of return condensate is saturation water enthalpy at the return temperature.

 

Aux. Water Supply to ------------------------------------------------------------------------------------------------------------------

To select whether the Aux. Water is supplied or not.

User may input the title of the auxiliary water in the text box beside, which shall be written in text output.

 

Water Supply Source combo box

 To select the water source of Aux. Water.   Selection list includes BFP Discharge and GSC(Gland Steam Condenser) Outlet.

In case that BFP Discharge is selected, auxiliary water supply to both of boiler attemperators and external use is possible.   But, in case of GSC Outlet, only supply to external use is possible, because GSC Outlet feed water pressure is not sufficient for boiler attemperators.

 

Water Supply Flow Rate text box

To input flow rate of Aux. Water to be supplied.

 

For Boiler Reheater Attemperator, For Boiler Superheater Attemperator, For External Use(Make-up to Condenser) option buttons

To select the user of Aux. Water.

In case of Boiler Reheat Attmperator and Boiler Superheater Attemperator, make-up water supplement to the turbine cycle is not required.   In case of External Use, make-up water supplement to the condenser is required.

 

Subtract Aux. Steam/Water Heat Output from Heat Input in Heat Rate Calculation -----------------------------------------------------

To select whether the heat output of auxiliary steams and auxiliary water shall be subtracted from the heat input(= denominator) in heat rate calculation.

If the auxiliary steam and auxiliary water is used for the boiler that supplies the steam required by the turbine cycle, the heat output is generally NOT considered(= subtracted) in heat rate calculation, because the heat output is regarded as credits in boiler efficiency calculation and no need to be considered in turbine cycle heat rate calculation.

However, if the auxiliary steam and auxiliary water is supplied to real external users, the heat output should be considered(= subtracted in denominator) in heat rate calculation as credits.

 


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