Thermodynamic Modeling and Validation of a 210-MW Capacity Coal-Fired Power Plant

Ravinder Kumar

doi:10.1007/s40997-016-0025-5

Iranian Journal of Science and Technology, Transactions of Mechanical Engineering

September 2016, Volume 40, Issue 3, pp 233–242 | Cite as

Thermodynamic Modeling and Validation of a 210-MW Capacity Coal-Fired Power Plant

Authors
Authors and affiliations

Ravinder KumarEmail author

Research Paper

First Online: 05 July 2016

Received: 19 February 2016

Accepted: 25 June 2016

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Abstract

This paper presents the thermodynamic modeling and validation of a 210-MW subcritical coal-fired power plant situated in North India. In the era of high computing facilities available, modeling and simulation have become a very pertinent tool for design and development. As such, the objective of the present work is not to enhance the thermal conversion efficiency, but to represent the thermal system in a simplistic yet functional manner. The thermal performance module consists of the following main sections such as steam boiler, economizer, superheater, reheater, steam turbine, condensate extraction pump, boiler feed pump, feedwater heaters and condenser. Thus, a semi-empirical module has been developed to predict thermal performance of coal-fired power plant. It includes the mass balance, energy balance, thermodynamic property relations for working substance followed by empirical correlations for steam bled pressure and thermodynamics of a steam power cycle. By using the MATLAB calculation tool, a process-based computer program of the coal-fired power plant has been successfully validated for thermal efficiency, steam flow rate and coal consumption rate at wide plant load range. The predictions were compared with operating data of 210-MW thermal power plant at different power output levels. The predicted results agree with plant operating data.

Keywords

Thermal performance analysis Thermodynamic model Coal-fired power plant Boiler efficiency Plant efficiency

List of symbols

BF: Boiler feed pump
CEP: Condensate extraction pump
CM, GM: Gland steam leakage collector
COND: Condenser
C_pw: Specific heat capacity of working substance
Cina: Carbon content in ash
DR: Deaerator
DC: Drain cooler
ECO: Economizer
EJE: Ejector
ETD: Entry temperature difference
FW: Feedwater
GSC: Gland steam condenser
GCV_coal: Gross calorific value of coal (kJ kg⁻¹)
HPT: High-pressure turbine
HPH: High-pressure feedwater heater
h: Enthalpy (kJ kg⁻¹)
h_s(i): Enthalpy of superheated steam (kJ kg⁻¹)
h_f(i): Enthalpy of feedwater at exit (kJ kg⁻¹)
h_f(i+1): Enthalpy of feedwater at entry (kJ kg⁻¹)
h_c(i): Enthalpy of condensate (kJ kg⁻¹)
IPT: Intermediate pressure turbine
IPH: Intermediate pressure feedwater heater
LPT: Low-pressure turbine
LPH: Low-pressure feedwater heater
m_coal: Coal consumption rate (ton h⁻¹)
m_uw: Unit mass flow rate of water (ton h⁻¹)
MWe: Net power output
MW: Plant capacity
NCV_coal: Net calorific value of coal (kJ kg⁻¹)
P: Pressure in bar
P_i: Pressure of bled steam at various locations from turbine
P_op: Power output of turbine
Q_i: ‘ith’ loss in boiler
RH: Reheater
SH: Superheater
T_f: Temperature of flue gas at air preheater outlet
T_a: Forced draft fan inlet temperature
TTD: Terminal temperature difference
W_t: Work done by turbine
x_i: Fractional mass flow rate of steam at ‘ith’ state

Greek symbols

η_plant: Overall thermal efficiency of the plant
η_boiler: Boiler efficiency

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Appendix: Properties Modeling of Working Substance

The thermodynamic properties of water in unsaturated, saturated and superheated conditions have been obtained from a curve fit to the thermodynamic data originally by Keenan and Keyes Steam Tables.

The enthalpy of saturated water is obtained in the following form

$$hu = - 1.40069 \times 10^{ - 09} \,p^{6} + 9.91868 \times 10^{ - 07} \,p^{5} - 2.68248 \times 10^{ - 04} \,p^{4} + 3.47195 \times 10^{ - 02} x^{3} - 2.21241\,p^{2} + 69.1350\,p + 244.324$$

(35)

The graphical presentation is given in Fig. 11.

Fig. 11
Comparing pressure–enthalpy (P–h) relation of saturated water

The empirical fit of entropy in terms of pressure of saturated water is graphically presented in Fig. 12.

Fig. 12
Pressure–entropy (P–S) of diagram of coal-fired power plant

Enthalpy of water vapor in superheated conditions is obtained from a curve fit to the thermodynamic data originally by Keenan and Keyes Steam Tables in the following form

$$h = a_{1} + a_{2} p^{0.25} + a_{3} s^{2} + a_{4} ps^{1.5} + a_{5} p^{2} s + a_{6} ps^{2.25} + a_{7} p^{2.05} s^{1.05}$$

(36)

The values of constants are listed in Table 4.

Table 4

Values of constants as given in Eq. (36)

Constants	Values
a ₁	−1874.611439
a ₂	1660.483139
a ₃	48.58941216
a ₄	−8.488375390
a ₅	0.4763079920
a ₆	1.369549685
a ₇	−0.3151976165

Equation 36 is valid in the pressure range of 0.1–175 bar and entropy in the range of 5–11.6 (kJ kg K) with coefficient of determination of 0.9198 and with percentage error (average) of 3.0258 and RMS error of 0.1888.

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Authors and Affiliations

Ravinder Kumar
- 1
Email author

1.Department of Mechanical EngineeringMaharishi Markandeshwar UniversityMullanaIndia

Thermodynamic Modeling and Validation of a 210-MW Capacity Coal-Fired Power Plant

Abstract

Keywords

List of symbols

Greek symbols

References

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