Ppc Calc Details

TechniNote

TN GMSCD0

ical

0903-01E

YokogaMarex Tel.: +4

I

awa Marex LimitedHouse, 34 Medina 44 (0)1983 296011

ExaquInstrume

Road, Cowes, Isle Fax: +44 (0)1983

uantum/Pntation R

e of Wight, PO31 7D291776

PPC PlanRequirem

DA, England ©

t ents

TN GMSCD090©Copyright R2.70 Is

23rd Octobe

03-01Essue 2r 2012

TN GMSCD0903-01E Exaquantum/PPC Instrumentation Requirements: Technical Note

1

DOCUMENT REVISION RECORD

Date Issue No Revised Sections Description of Change

13thJuly 2011 1 First Issue First Issue

23rd October 2012 2 Second Issue Second Issue

1. INTRODUCTION ......................................................................................................................................... 2 2. BOILER PERFORMANCE CALCULATIONS ............................................................................................... 3

2.1. ASME Standard: Fired Steam Generators PTC 4 – 2008 ...................................................................... 3 2.2. PTC 4 – Part One: Efficiency calculation by Direct Method ................................................................... 3

2.2.1. Instrumentation Required for Efficiency Calculation by Direct Method ............................................ 4 2.2.2. Other Information Required for Efficiency Calculation by Direct Method ......................................... 5 2.2.3. Additional Instrumentation required for more complex systems ...................................................... 5

2.3. PTC 4 – Part Two: Efficiency calculation by Indirect (Heat Loss) Method ............................................. 7 2.3.1. Instrumentation Required for Efficiency Calculation by Indirect Method .......................................... 8 2.3.2. Other Information Required for Efficiency Calculation by Indirect Method ...................................... 9

2.4. Enhanced PPC Boiler Calculations ....................................................................................................... 9 2.5. ASME Standard: Gas Turbine Heat Recovery Steam Generators PTC 4.4 – 2008 ............................. 10

2.5.1. Instrumentation Required for HRSG Efficiency Calculation .......................................................... 11 2.5.2. Other Information Required for HRSG Efficiency Calculation ....................................................... 13

3. STEAM TURBINE PERFORMANCE CALCULATIONS ............................................................................. 14 3.1. Theoretical Turbine Efficiency ............................................................................................................. 14

3.1.1. Instrumentation Required for Turbine Efficiency Calculation ......................................................... 14 3.1.2. Other Information Required for Turbine Efficiency Calculation ...................................................... 15

3.2. ASME Standard: Steam Turbines PTC 6 – 1996 ................................................................................ 15 3.2.1. Instrumentation Required for Turbine Efficiency Calculation ......................................................... 16 3.2.2. Other Information Required for Turbine Efficiency Calculation ...................................................... 16

4. GAS TURBINE PERFORMANCE CALCULATIONS .................................................................................. 17 4.1. ASME Standard: Gas Turbines PTC 22 – 1997 .................................................................................. 17

4.1.1. Instrumentation Required for Gas Turbine Efficiency Calculation ................................................. 18 4.1.2. Other Information Required for Gas Turbine Efficiency Calculation .............................................. 18

5. UNIT HEAT RATE PERFORMANCE CALCULATIONS ............................................................................ 19 5.1. ASME Standard: Overall Plant Performance PTC 46 – 1996 ............................................................. 19

5.1.1. Instrumentation Required for Plant Performance Calculation........................................................ 19 5.1.2. Other Information Required for Plant Performance Calculation .................................................... 19

6. UNIT DEVIATION COST CALCULATIONS ............................................................................................... 21 6.1.1. Other Information Required for Unit Deviation Cost Calculation ................................................... 21

7. CONDENSER PERFORMANCE CALCULATIONS ................................................................................... 22 7.1. ASME Standard: Steam Surface Condensers PTC 12.2 – 1998 ......................................................... 22

7.1.1. Instrumentation Required for Condenser Efficiency Calculation ................................................... 22 7.1.2. Other Information Required for Condenser Efficiency Calculation ................................................ 23

8. FEEDWATER HEATER PERFORMANCE CALCULATIONS .................................................................... 25 8.1.1. Instrumentation Required for Feedwater Heater Performance Calculation ................................... 25 8.1.2. Other Information Required for Feedwater Heater Performance Calculation ................................ 25

9. AIR HEATER PERFORMANCE CALCULATIONS .................................................................................... 26 9.1.1. Instrumentation Required for Air Heater Performance Calculation ................................................ 26 9.1.2. Other Information Required for Air Heater Performance Calculation ............................................ 26

10. OTHER INFORMATION .......................................................................................................................... 27


2

1. INTRODUCTION

The aim of this document is to allow a customer to assess whether they have sufficient instrumentation to satisfy the requirements of the Exaquantum/PPC (Power Performance Calculations) application. Exaquantum/PPC is an ASME compliant performance calculation package used in power generation plants to determine the efficiency of plant equipment. In general Exaquantum/PPC will determine the online performance and efficiency of plant equipment and compare it with design values or norms. These design values can come from regression analysis of existing plant data, expert knowledge of the plant, or in most cases from equipment manufacturer’s datasheets. This document will also indicate what design values are required. Simply fill in the details of what instrumentation and design values are available, and your local Yokogawa sales office will be able to give you advice regarding the application of Power Performance Calculations to your plant. Your local Yokogawa sales office will also be pleased to provide a quotation for customizing the Exaquantum/PPC Power Performance Calculations to suit your plant/requirements and/or advice regarding additional instrumentation.


3

2. BOILER PERFORMANCE CALCULATIONS

Performance and efficiency of a boiler reduces with time for a number of reasons, including: Poor combustion Heat Exchanger fouling Poor maintenance Poor operation

Exaquantum/PPC will allow energy efficiency improvements to be made by tracking variation from design values. It can also assign a cost to these variations so that expensive, but easily correctable situations can be prioritized and remedied.

2.1. ASME Standard: Fired Steam Generators PTC 4 – 2008

There are two parts to the ASME Standard which Exaquantum/PPC employs: - o Part One: Direct method (also known as the Input-Output method) o Part Two: Indirect method (more commonly known as the Boiler Efficiency by Heat Loss method,

or simply Heat Loss method) Exaquantum/PPC uses the rules and instructions described by the standard for conducting performance evaluation of fuel fired steam generators. These include coal, oil, and gas fired steam generators as well as steam generators fired by other hydrocarbon fuels.

2.2. PTC 4 – Part One: Efficiency calculation by Direct Method

The direct method used by Exaquantum/PPC has the following advantages over the Heat Loss Method: - 1. Easier to implement 2. Requires fewer parameters for calculation 3. Needs fewer instruments

This method for determining the efficiency of a boiler is also known as the Input-Output method because it only requires the heat input from the fuel and the heat output as steam for its calculations.

Figure 2-1 Direct Boiler Efficiency Calculation


4

loss water WLand blowdown BD feedwater, FW where

100valuecalorific gross Fuel rateflow Fuel

enthalpy) feedwater -enthalpy (steam flow) WL-flow BD -flow (FW

eunavailabl is rateflow steam whenform ealternativ Or

100valuecalorific gross Fuel rateflow Fuel

enthalpy) feedwater -enthalpy (steam rateflow Steam

100Fuel in heat Gross

Steam in Heat

100Input Heat

Output HeatEfficiency

2.2.1. Instrumentation Required for Efficiency Calculation by Direct Method

Measurement Notes Available in your plant

Fuel flow rate Mass or Volume □

Steam flow rate Mass or Volume. Can be replaced with feedwater flow rate if water losses can be accounted for (e.g. blowdown)

□

Steam pressure For steam enthalpy calculation □

Steam temperature For steam enthalpy calculation □

Feedwater flow rate Mass or Volume. Only required if steam flow rate is unavailable. □

Feedwater Temperature

For feedwater enthalpy calculation. Taken at boundary of boiler. □

Blowdown flow rate Mass or Volume. Only required if steam flow rate is unavailable and Feedwater flow rate is used.

□

Blowdown Temperature

For feedwater enthalpy calculation. Taken at boundary of boiler. Only required if steam flow rate is unavailable and Feedwater flow rate is used.

□

Other water loss flow rates

Mass or Volume. Only required if steam flow rate is unavailable and Feedwater flow rate is used.

□

Other water loss temperature

For water loss enthalpy calculation □


5

2.2.2. Other Information Required for Efficiency Calculation by Direct Method

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableCalorific value (Higher Heating Value) of fuel

Constant, from Laboratory Analysis or as quoted by fuel supplier. □

Boiler efficiency curve Typically quoted as a function of Steam Flow. □

2.2.3. Additional Instrumentation required for more complex systems

Figure 2-2Complex Direct Efficiency Calculation

In a more complex system there may be multiple paths for the output steam flow, and more than one input flow to be heated; for instance, multiple feed water paths or cold steam for reheat. The following additional measurements may be required for your system.


Superheated Steam flow rate

Mass or Volume. □

Superheated Steam temperature

For steam enthalpy calculation □

Superheated Steam pressure


Hot Reheat Steam flow rate

Mass or Volume. □

Hot Reheat Steam temperature



6


Hot Reheat Steam pressure


Cold Reheat Steam flow rate

Mass or Volume. □

Cold Reheat Steam temperature


Cold Reheat Steam pressure


Superheat Spray water flow rate

1st stage and 2nd stage. Mass or Volume. □

Reheat Spray water flow rate

Mass or Volume. □

Superheat Spray water Temperature

For feedwater enthalpy calculation. Only required if steam flow rate is unavailable and Feedwater flow rate is used.

□

Reheat Spray water Temperature

For feedwater enthalpy calculation. Only required if steam flow rate is unavailable and Feedwater flow rate is used.

□

Please indicate in the space below, any additional information that is relevant to your system: Additional Information about your boiler


7

2.3. PTC 4 – Part Two: Efficiency calculation by Indirect (Heat Loss) Method

The Indirect (Heat Loss) method provides the following benefits: - 1. Indicates why the efficiency of the system is lower 2. Assigns a cost to each Heat Loss 3. Allows finer tuning of Boiler design characteristics 4. Result is less affected by measurement errors

This method for determining the efficiency of a boiler works by subtracting all of the heat losses associated with the boiler from 100. Thus if all the losses add up to 10%, then the boiler will be 90% efficient. The advantage of this method is that an error in the measurements will have a smaller impact than errors in the Direct Method measurements. Compare:- For Direct method a 1% error will lead to a calculation of 90% ±1% = 89.1% to 90.9% For Indirect method a 1% error will lead to calculation of 100% – (10%±1%) = 89.9% to 90.1%

STEA

M OUTPUT

FUEL INPUT

AIR

BOILER

FLUE GAS

FEED

WATER

BLO

WDOWN

SOLID FUEL RESIDUE

L2.Loss due to Hydrogen in Fuel

L1. Dry Flue Gas Loss

L3. Loss due to Moisture in Fuel

L4. Loss due to Moisture in Air

L5. Loss due to Carbon Monoxide

L6. Surface Loss

L8. Bottom Ash Loss

L7. Unburnt loss in Fly Ash

Figure 2-3 Heat Loss Efficiency Calculation

Efficiency = 100 – (LI+L2+L3+L4+L5+L6+L7+L8) Where: L6 = Loss due to surface radiation, convection and losses which are insignificant or difficult to measure. Can be calculated if the surface area and surface temperature of the boiler are known, orcan be derived from manufacturer’s data, else can be assumed as follows: -

o Industrial fire tube / packaged boiler = 1.5% to 2.5% o Industrial watertube boiler = 2% to 3% o Power station boiler = 0.4% to 1%

And: L7 and L8 apply to solid fuel fired boilers only


8

2.3.1. Instrumentation Required for Efficiency Calculation by Indirect Method

In addition to the instruments previously defined, this function block requires the following measurements:


Flue Gas temperature For enthalpy calculation □ Percentage of CO2 or O2 in flue gas

From flue gas analysis. O2 measurement preferred. □

Percentage of COin flue gas From flue gas analysis □

Steam flow rate Mass or Volume. Could be several instruments for instance Superheated Steam flow + Reheated Steam flow.

□

Steam temperature

For enthalpy calculation. Could be several instruments for instance Superheated Steam temperature, Cold Reheated Steam temperature, Hot Reheated steam temperature.

□

Steam pressure For enthalpy calculation. Could be several instruments for instance Superheated Steam temperature and Reheated Steam temperature.

□

Condensate water flow rate Mass or Volume. □

Condensate return temperature For enthalpy calculation □

Combustion air flow rate Mass or Volume. □

Combustion air temperature For enthalpy calculation □

Combustion air pressure For enthalpy calculation, both primary and secondary □

Makeup water temperature For enthalpy calculation □

Fuel temperature For enthalpy calculation □

Fuel pressure For enthalpy calculation: not required for solid fuel fired boilers. □

Boiler surface temperature Optional: For calculation of L6 □

Ambient temperature Optional: For calculation of L6 □

Wind speed Optional: For calculation of L6 □

Draft pressure For enthalpy calculation □

Atmospheric humidity For calculation of L4. □

Boiler drum pressure For enthalpy calculation □

Boiler drum temperature For enthalpy calculation □


9

2.3.2. Other Information Required for Efficiency Calculation by IndirectMethod

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableCalorific value (Higher Heating Value) of fuel

From Laboratory Analysis or as quoted by fuel supplier. □

% Carbon in fuel by weight

From Laboratory Analysis of the fuel. □

% Sulfur in fuel by weight


% Hydrogen in fuel by weight


% Nitrogen in fuel by weight


% Oxygen in fuel by weight


% Water in fuel by weight


% Ash in fuel by weight

From Laboratory Analysis of the fuel. Solid fuels only □

% Carbon in refuse by weight

From Laboratory Analysis of the refuse. Solid fuels only □

% Ash in refuse by weight


Calorific value (Higher Heating Value) of carbon in refuse


Boiler efficiency curve Design values (from manufacturer). Typically quoted as a function of Steam Flow. □

Boiler efficiency loss due to radiation curve

Optional: For calculation of L6 Design values (from manufacturer). Typically quoted as a function of Steam Flow.

□

2.4. Enhanced PPC Boiler Calculations

The ASME calculations described previously do not take into account the following losses: - 1. Blow down losses. 2. Auxiliary steam consumption; for instance Soot Blowers.

They also do not highlight the efficiency of individual components. However, Exaquantum/PPC contains additional calculations to make use of any additional measurements/information that might be available.


Auxiliary Steam flow Mass or Volume. For Unit Heat rate and cost calculations □

Auxiliary Steam pressure For Unit Heat rate and cost calculations □

Reheat Steam temperature For Unit Heat rate and cost calculations □

Reheat Spray flow Mass or Volume. For Unit Heat rate and cost calculations □

Reheat Spray pressure For Unit Heat rate and cost calculations □

Reheat Spray temperature For Unit Heat rate and cost calculations □


10


Economizer Feedwater inlet temperature

For Unit Heat rate and cost calculations □

Percentage of SO2in flue gas From flue gas analysis □

Percentage of NOXin flue gas From flue gas analysis □ In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableExpected Excess Air curve

Design values. Typically quoted as a function of Steam Flow. □

Expected Steam temperature curve


Expected Hot Reheat temperature curve


Expected Economizer Inlet Water temperature curve


Expected Blowdown flow curve


2.5. ASME Standard: Gas Turbine Heat Recovery Steam Generators PTC 4.4 – 2008

This standard is used by Exaquantum/PPC for evaluating the performance of Heat Recovery Steam Generators (HRSGs) employed in combined cycle installations. A combined cycle shall be interpreted as a gas turbine exhausting intoan HRSG. There are two methodsto determine the efficiency of an HRSG as it is for boiler efficiency in PTC 4.

o Direct (Input-Output) method

streams steam and air, atomizing

air, augmenting fuel,ary supplement gas, exhaust the of each denotes stream" Each"

heaters. Waterand LP, IP, Reheat, HP, the of each denotes water"steam, Each"

: Where

100stream each for enthalpy)} Reference -enthalpy (Inlet rateflow Inlet{

watersteam, each for enthalpy)} inlet-enthalpy (outlet rateflow {

100credits heatfuelary supplement in heat gas exhaust turbine gas in Heat

fluids by working absorbed Heat

100(kJ/h) Input Heat

(kJ/h) Output Heat(%) Efficiency


11

o Indirect (Heat Loss) method

velocity. and etemperatur the of functions are losses heat convection and Radiation

enthalpy gas exhaust Reference-enthalpy gas exhaust Outlet flow gas inlet gas exhaust moist in loss Heat

loss heat convective loss heat radiation gas exhaust moist in loss heat losses Heat

100input Heat

losses Heat1100

(kJ/h) Input Heat

(kJ/h) losses Heat - Input Heat(%) Efficiency

2.5.1. Instrumentation Required for HRSG Efficiency Calculation


Barometric pressure For calculation of exhaust gas enthalpy and heat input □ Ambient relative humidity

For calculation of exhaust gas enthalpy and heat input □

Ambient dry bulb temperature


Inlet gas temperature For calculation of exhaust gas enthalpy and heat input □ Outlet gas temperature


Inlet augmenting air temperature

For calculation of total heat and flow rate with supplemental firing □

Inlet fuel temperature For calculation of total heat and flow rate with supplemental firing □ Inlet atomizing steam temperature


Fuel gas flow rate Mass flow For calculation of total heat and flow rate with supplemental firing □

Atomizing steam flow rate

Mass flow For calculation of total heat and flow rate with supplemental firing □

Augmenting air flow rate

Mass flow For calculation of total heat and flow rate with supplemental firing □

Fuel gas flow rate Mass flow For calculation of total heat and flow rate with supplemental firing □

HP steam temperature For calculation of heat output □

HP steam pressure For calculation of heat output □

HP steam flow rate Mass flow.-For calculation of heat output □ Reheat outlet steam temperature

For calculation of heat output □

Reheat outlet steam pressure


Reheat outlet steam flow rate

Mass flow, Calculation of heat output □

Reheat inlet steam temperature

Calculation of heat output □

Reheat inlet steam pressure

Calculation of heat output □

Reheat inlet steam flow rate

Mass flow.-For calculation of heat output □


12

IP steam temperature Calculation of heat output □

IP steam pressure For calculation of heat output □

IP steam flow rate Mass flow.-For calculation of heat output □ LP steam SH outlet temperature


LP steam SH outlet pressure


LP steam SH outlet flow rate

Mass flow.- Forcalculation of heat output □

LP steam EV outlet temperature


LP steam EV outlet pressure


LP steam EV outlet flow rate


Water heater inlet water temperature


Water heater inlet water pressure


Water heater inlet water flow rate

Mass flow.- For calculation of heat output □

Water heater outlet water temperature


Water heater outlet water pressure


Water heater outlet water flow rate


LP Feed water temperature


LP Feed water pressure


LP Feed water flow rate


HP Feed water temperature


HP Feed water pressure


HP Feed water flow rate


IP Feed water temperature


IP Feed water pressure


IP Feed water flow rate


Ambient temperature For calculation of heat loss □ Surface temperature For calculation of heat loss □ Forced convection air velocity

For calculation of heat loss □


13

2.5.2. Other Information Required for HRSG Efficiency Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableMethane, ethane, propane, iso-butane, n-butane,…and nitrogen

Mole fractions of dry gas fuel compositions (from Section 4.1.2, “4.1.2. Other Information Required for Gas Turbine Efficiency Calculation)

□

Carbon monoxide Mole fraction of dry gas fuel □

Sulfur Mole fraction of dry gas fuel □

Sulfur dioxide Mole fraction of dry gas fuel □

Oxygen Mole fraction of dry gas fuel □ Exhaust gas reference temperature


Weight ratio of steam or water injection


Fuel to gas ratio Supplementary firing fuel-to-exhaust gas (gas turbine outlet) ratio. For calculation of exhaust gas enthalpy □

Fuel to air ratio Gas turbine fuel-to-inlet air ratio (air entering evaporative coolers, if utilized). For calculation of exhaust gas enthalpy □

Mean specific heat of fuel


Lower heat value of supplementary fuel


Emissivity Radiation loss. Emissivitycalculation of heat loss □

Area of surface factor Area of surface though which heat loss occurs for radiation and convection. For calculation of heat loss □


14

3. STEAM TURBINE PERFORMANCE CALCULATIONS

Exaquantum/PPC will allow energy efficiency improvements to be made by tracking Steam Turbine operating variation from design values. It can also assign a cost to these variations so that expensive, but easily correctable situations can be prioritized and remedied.

3.1. Theoretical Turbine Efficiency

The method that Exaquantum/PPC uses for calculation of Steam Turbine Efficiency employs the Isentropic Enthalpy of the Exhaust Steam.

Figure 3-1 Steam Turbine efficiency calculations

100turbine the across dropenthalpy al)(theoretic Isentropic

turbine the accros dropenthalpy ActualEfficiency

3.1.1. Instrumentation Required for Turbine Efficiency Calculation



Throttle Steam temperature (Main Steam Temperature) □

Throttle Steam pressure (Main Steam Pressure) □ HP Turbine Exhaust Steam temperatures

(Cold Reheat Steam Temperature) □

HP Turbine Exhaust Steam pressures

(Cold Reheat Steam Pressure) □

IP Turbine Inlet Steam temperature

(Hot Reheat Steam Temperature) □

IP Turbine Inlet Steam Pressure (Hot Reheat Steam Pressure) □ IP Turbine Exhaust Steam temperatures

□

IP Turbine Exhaust Steam pressures

□


15


Crossover pressure to LP Turbine

□

Crossover temperature to LP Turbine

□

3.1.2. Other Information Required for Turbine Efficiency Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableExpected Turbine efficiency curves

Design values (from manufacturer). Typically quoted as a function of generator load. □

3.2. ASME Standard: Steam Turbines PTC 6 – 1996

This standard is used by Exaquantum/PPC for evaluating the performance of steam turbines operating either with a significant amount of superheat in the initial steam (typically fossil fuelled units) or predominantly within the moisture region (typically nuclear fuelled units). For turbines operating in a regenerative or reheating cycle, PTC-6 states that steam turbine performance shall be expressed as Heat Rate, thus:

Output

cycle the to heat NetRate Heat

Where “Net heat to the cycle” represents the boiler heat input to the turbine cycle. Heat rate is the heat consumption per hour per unit output, with units of kJ/kWh. This takes into account the useful energy from the steam vs. the electricity generated.

Figure 3-2Heat Balance around Turbine Cycle


16

Net heat to cycle = Heat added to Main Steam –Steam Losses - Heat returned from Turbine or

= Heat flow entering turbine – Heat flow leaving turbine Where: Heat added to Main Steam =

(Heat in Main Steam – Heat in Feedwater – Heat in Superheat Spray – Heat in Reheat Spray) Heat flow entering turbine = HP turbine inlet heat flow + IP turbine inlet heat flow

+ LP turbine inlet heat flow Heat flow leaving turbine = HP turbine outletheat flow + Feedwater to steam generator heat flow Where: (Heat flow = Enthalpy ×Flow rate)

3.2.1. Instrumentation Required for Turbine Efficiency Calculation



Gross power from generator □

HP turbine inlet flow rate See Section 3.1.1 for temperature and pressure. □ HP turbine exhaust flow rate See Section 3.1.1 for temperature and pressure. □ IP turbine inlet flow rate See Section 3.1.1 for temperature and pressure. □ LP turbine inlet flow rate See Section 3.1.1 for temperature and pressure. □ Feedwater temperature □ Feedwater pressure □ Feedwater flow rate □

3.2.2. Other Information Required for Turbine Efficiency Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableMax rating of generator.

Constant □


17

4. GAS TURBINE PERFORMANCE CALCULATIONS

Exaquantum/PPC will allow energy efficiency improvements to be made by tracking Gas Turbine operating variation from design values.

4.1. ASME Standard: Gas Turbines PTC 22 – 1997

This standard is used by Exaquantum/PPC for evaluating the performance of gas turbines operating on a gas fuel.

Figure 4-1Gas Turbine efficiency calculations

(1) Gas turbine thermal efficiency Thermal efficiency is calculated from the heat input and power measurements as follows:

100(kJ/h) input Heat

(kW) output Power(%) efficiency Thermal

Heat rate (HR) is basically a reciprocal of thermal efficiency. It can be calculated from the heat input divided by the power output or thermal efficiency.

(kW) output Power

(kJ/h) input Heat(kJ/kWh) rate Heat

(2) Determination of power output Gas turbine power output shall be measured by determination of the electric generator output. Net electrical power output of a gas turbine with a generator is equal to the electrical output at the generator terminals minus the electrical power separately supplied for generator excitation and other specified plant auxiliaries. (3) Determination of heat input on gas fuels To determine the heat input while operating on a gas fuel, the following parameters shall be determined:

(a) Density at operating conditions (b) Volume flow (c) Gas composition, including moisture content (gas constant from chromatograph analysis) (d) Heat value


18

The fuel gas heat input is calculated from the following equation:

(kJ/h) heat Sensible (kJ/kg) value heatLow (kg/m3)Density (m3/h)flow Volume(kJ/h) input Heat

4.1.1. Instrumentation Required for Gas Turbine Efficiency Calculation



Fuel gas temperature Operating temperature at the flow meter □

Fuel gas pressure Operating pressure at the flow meter □

Fuel gas dew point temperature For calculation of mole fraction of water in the fuel □

Volumetric fuel flow If a turbine meter is used, this is calculated from the frequency and calibration factor K. □

Turbine meter frequency If a turbine meter is used, provide calibration factor K for calculating the flow rate from the frequency. □

Power output Net power output □

4.1.2. Other Information Required for Gas Turbine Efficiency Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes Available

Calibration factor K If turbine meter is used, the volumetric fuel flow is calculated from the meter frequency and calibration factor K. □

Methane Mole fraction of dry gas fuel composition (from chromatograph) □ Ethane Mole fraction of dry gas fuel composition (from chromatograph) □ Propane Mole fraction of dry gas fuel composition (from chromatograph) □ Iso-Butane Mole fraction of dry gas fuel composition (from chromatograph) □ N-Butane Mole fraction of dry gas fuel composition (from chromatograph) □ Iso-Pentane Mole fraction of dry gas fuel composition (from chromatograph) □ N-Pentane Mole fraction of dry gas fuel composition (from chromatograph) □ N-Hexane Mole fraction of dry gas fuel composition (from chromatograph) □ Carbon dioxide Mole fraction of dry gas fuel composition (from chromatograph) □ Nitrogen Mole fraction of dry gas fuel composition (from chromatograph) □


19

5. UNIT HEAT RATE PERFORMANCE CALCULATIONS

Heat rate is the heat consumption per hour per unit output, with units of kJ/kWh. This takes into account the useful energy from the fuelvs. the electricity generated and is an indication of overall plant performance.

5.1. ASME Standard: Overall Plant Performance PTC 46 – 1996

Employing thisstandard allows Exaquantum/PPC to determine the performance of the entire heat cycle of an integrated system which can be used for either comparison to a design number, or to trend performance changes over time of the overall plant.

Figure 5-1Plant Performance

5.1.1. Instrumentation Required for Plant Performance Calculation



Steam Coil steam flow □

Generator VAR □ Auxiliary Power □

5.1.2. Other Information Required for Plant Performance Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableGross Turbine-Generator Heat Rate curve

Design values (from manufacturer). Typically quoted as a function of Gross Generation. □

Condenser Back-Pressure deviation effect curve

The effect that a change in condenser back-pressure will have on the unit heat rate. Quoted as a function of Main Steam flow.

□


20

Information Notes AvailableSuperheat Steam temperature deviation effect curve

The effect that a change in Superheat Steam temperature will have on the unit heat rate. Quoted as a function of Throttle Steam temperature.

□

Reheat Steam temperature deviation effect curve

The effect that a change in Reheat Steam temperature will have on the unit heat rate. Quoted as a function of Reheat Steam temperature.

□

Superheat Steam pressure deviation effect curve

The effect that a change in Superheat Steam pressure will have on the unit heat rate. Quoted as a function of Throttle Steam pressure.

□

Reheat Steam pressure deviation effect curve

The effect that a change in Reheat Steam pressure will have on the unit heat rate. Quoted as a function of Reheat Steam pressure drop (between Cold Reheat Steam pressure and Hot Reheat Steam pressure.

□

Auxiliary Power standard curve

The expected loss to Auxiliary power. Typically quoted as a function of gross power from generator. □

Steam Leakage Other losses of steam specific to the plant. Typically quoted as a function of Main Steam flow.

Max rating of generator.

Constant. □


21

6. UNIT DEVIATION COST CALCULATIONS

Each deviation of an equipment item from its optimum design setting will result in a performance cost. These performance costs can be calculated as a monetary cost by taking into account the cost of fuel.

Figure 6-1 Unit Deviation Costs

6.1.1. Other Information Required for Unit Deviation Cost Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes Available

Cost of fuel □


22

7. CONDENSER PERFORMANCE CALCULATIONS

The expected (optimum) value of the condenser pressure is calculated as a function of the saturated steam temperature in the condenser, and as a function of the Limiting Terminal Temperature Difference.

Figure 7-1CondenserFlow Diagram

7.1. ASME Standard: Steam Surface Condensers PTC 12.2 – 1998

Employing this standard allows Exaquantum/PPC to determine the following performance indexes:

o Difference in steam pressure between the calculated value and design value. o Difference in tube-side pressure drop between the measured value and design value.

Above indexesare calculated by the following parameters. Heat load Heat transfer coefficient Log mean temperature difference (LMTD) Tube-wall resistance Fouling resistance Shell-side resistance Tube-side resistance

7.1.1. Instrumentation Required for Condenser Efficiency Calculation



Condenser back pressure □

Cooling water inlet temperature For calculations of specific heat, thermal conductivity, viscosity, density, heat load, LMTD and fouling resistance □


23

Cooling water outlet temperature

For calculations of specific heat, thermal conductivity, viscosity, density, heat load and LMTD □

Cooling water flow rate For calculation of heat load □ LP turbine exhaust steam pressure

For calculation of saturated temperature □ LP Turbine exhaust steam temperature

For calculation of saturated temperature □

Condensing steam/water flow For calculation of shell-side resistance □ Tube-side pressure drop For calculation of pressure drop deviation □

7.1.2. Other Information Required for Condenser Efficiency Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableLimiting terminal temperature difference

Constant, from manufacturer’s data □

Condenser heat transfer correction factor

Constant, from manufacturer’s datain case of no calculation □

Tube thermal conductivity Condenser design data □ Tube outer diameter Condenser design data □ Tube inner diameter Condenser design data □ Outside tube surface area Condenser design data □ Cooling water flow area Condenser design data □ Cleanliness factor Condenser design data □ Heat load Condenser design data □ Cooling water flow-rate Condenser design data □ Condensing flow-rate Condenser design data □ Cooling water inlet temperature Condenser design data □ Cooling water outlet temperature

Condenser design data □ Tube-side pressure drop Condenser design data □ LP turbine exhaust steam pressure

Condenser design data □ LP turbine exhaust steam saturated temp.

Condenser design data □ Bulk average temperature Condenser design data □ Specific heat capacity Condenser design data □ Thermal conductivity Condenser design data □ Viscosity Condenser design data □ Density Condenser design data □


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Number n tube-set outlet temperature (fouling)

Condenser test data where n indicates the tube-set number □

Number n tube-set outlet temperature (clean)

Condenser test data where n indicates the tube-set number □


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8. FEEDWATER HEATER PERFORMANCE CALCULATIONS

The expected (optimum) operating envelope of a feedwater heater can be characterized by the difference between the drain inlet and drain outlet.

Figure 8-1Feedwater Heater Flow Diagram

8.1.1. Instrumentation Required for Feedwater HeaterPerformance Calculation



Feedwater inlet temperature In a cascaded heater system, can be measured at the output of the previous heater. □

Feedwater outlet temperature In a cascaded heater system, can be measured at the input of the next heater. □

Inlet steam temperature In a cascaded heater system, can be measured at the output of the previous heater. □

Inlet steam pressure In a cascaded heater system, can be measured at the output of the previous heater. □

Drain inlet temperature In a cascaded heater system, can be measured at the output of the previous heater. □

Drain outlet temperature In a cascaded heater system, can be measured at the input of the next heater. □

8.1.2. Other Information Required for Feedwater HeaterPerformance Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableExpected terminal temperature difference curve

The expected temperature drop between the inlet/outlet drain temperatures. Typically quoted as a function of generator load.

□


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9. AIR HEATER PERFORMANCE CALCULATIONS

The efficiency of an air heater can be characterized by the differential temperatures of the air/gas flows.

Figure 9-1 Air Heater Flow Diagram

9.1.1. Instrumentation Required for Air Heater Performance Calculation



Gas inlet temperature In a cascaded heater system, can be measured at the output of the previous heater. □

Gas outlet temperature In a cascaded heater system, can be measured at the input of the next heater. □

Air inlet temperature In a cascaded heater system, can be measured at the output of the previous heater. □

9.1.2. Other Information Required for Air Heater Performance Calculation

In addition to the information previously defined, this function block requires the following design data: Information Notes AvailableExpected Air Heater efficiency curve

Typically quoted as a function of Main Steam flow. □


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10. OTHER INFORMATION

Please indicate in the space below, any other information that might be relevant to your system, for example:

Manual feeding of fuel Variation in fuel grade Reliability of Instruments Accuracy of Instruments Age of plant etc.

Additional Information about your system


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Documents

Ppc Calc Details