FEDERAL UNIVERSITY OF PETROLEUM RESOURCES, EFFURUN.
PRESENTATION OF M.ENG PROJECT PROPOSAL
ON
PERFORMANCE EVALUATION OF A COMBINED CYCLE CAPTIVE
POWER PLANT USING ASPEN HYSYS MODELLING TOOL TO
SIMULATE REAL-TIME OPERATIONAL DATA
BY
OGUNJI OYEDELE JOSEPH
MECHANICAL ENGINEERING DEPARTMENT
SUPERVISED BY: PROF O.D SAMUEL
INTRODUCTION
• A captive power plant is an electricity generation facility used by an industrial or commercial energy user
primarily for their own energy consumption. These plants can operate off-grid or be connected to the electric
grid to exchange excess generation.
• CCPP integrates gas turbines, heat recovery steam generators (HRSGs), and steam turbines to produce
electricity with enhanced thermal efficiency.
• This hybrid configuration capitalizes on the strengths of both the Brayton and Rankine thermodynamic cycles,
using the waste heat from the gas turbine to generate steam, which is then expanded in a steam turbine to
produce additional power.
STATEMENT OF PROBLEM
• The Combined Cycle Captive Power Plant is an advance technology for providing localized, efficient and reliable power to
specific operational need of industries, However, their performance often goes under examined, leading to untapped
opportunities for optimization, this has affected full adoption of CCCPP in some industries.
AIM AND OBJECTIVES
Aim
The aim of this project is to evaluate the performance of a captive combined cycle power plant by analyzing real-time operational data from
an existing gas turbine, HRSG, and steam turbine system, and simulating its performance using ASPEN HYSYS process modeling tools to
identify areas for efficiency improvement, cost reduction, and enhanced reliability.
Objectives
1. To collect and analyze real operational data from an existing captive combined cycle power plant involving gas turbine, HRSG, and
steam turbine systems.
2. To evaluate the thermodynamic performance of the individual components (gas turbine, heat recovery steam generator, and steam
turbine) based on parameters such as temperature, pressure, fuel consumption, and power output.
3. To simulate the combined cycle process using ASPEN HYSYS software tools in order to validate the collected data and predict system
performance under various operating conditions.
4. To determine the overall efficiency of the combined cycle system and compare it with theoretical values and industry benchmarks.
5. To assess the environmental performance of the plant, particularly emissions such as CO₂ and NOₓ, and examine the impact of
improved efficiency on emission reduction.
LITERATURE REVIEW
S/N
1
2
3
4
5
Adopted Plant
Explored Tool
Parameter Investigated
Utility-Scale Combined Simulation (EBSILON, Thermal efficiency, Power
Cycle Plant
ASPEN Plus)
output
Outcome/Response
Countries
Gap in Study
Lack of real operational data from captive
High performance under
USA, Germany or industrial plants under variable load
steady-state conditions
conditions (Zhang et al., 2020).
Combined Cycle (Gas + Thermodynamic
Steam Turbine)
modelling
HRSG efficiency, Steam
generation
Industrial Captive
Power Plant
Simulation and field
data analysis
Sparse research on dynamic behaviour of
Load variation, Fuel quality Performance sensitive to
gas turbines and HRSGs under siteIndia, Nigeria
impact
load and fuel variability
specific operational constraints regions
(Onoja & Adewole, 2022).
Combined Cycle Power
MATLAB-Simulink
Plant
Inadequate exploration of integrated gassteam turbine control schemes and their
real-time interaction (Rezaei &
Mostafaeipour, 2020).
Combined Cycle Gas
Power Plant
Control system dynamics
CFD and Thermo-fluid Exhaust heat recovery and
simulation
temperature profiles
Accurate predictions in
UK, Spain
idealized environments
Limited focus on HRSG behaviour during
transient loads and rapid cycling common
in industrial captive plants (Kumar & Das,
2019).
Effective under
coordinated tuning
Iran, China
Optimized heat transfer Brazil, Saudi
in HRSG
Arabia
HRSG thermal inertia and design
flexibility under fast start up/shutdown
scenarios in captive plants not thoroughly
examined (Costa et al., 2021).
6
7
8
9
10
Minimal application of AI-based
diagnostics and digital twins in
Increased equipment Japan, South developing countries’ captive
reliability and uptime Korea
systems due to data unavailability
and lack of integration
frameworks (Lee et al., 2020).
Utility-based
Combined Cycle
Plant
AI/Machine Learning
Industrial Combined
Cycle Plants
Efficiency gain with
ASPEN Plus + Excel Economic and environmental
retrofits; reduced
Modelling
performance
emissions
Netherlands,
Canada
Captive Plant
(Industrial Use)
Drop in efficiency at
Performance logging Ambient temperature effects,
high ambient
and reporting
Fuel consumption
temperatures
Few location-specific studies linking
climatic effects to design or
Nigeria, Ghana
operational changes in tropical
(Adewuyi & Usman, 2018).
Combined Cycle
Plants
Utility & Industrial
Plants
Predictive maintenance,
Fault detection
Support for gas-based
Policy and regulatory Emission targets, Fuel source
generation with flexible EU nations
reviews
diversification
regulation
Life Cycle Cost
(LCC), LCOE
ROI, Payback period, O&M
costs
Economic viability
under defined load
conditions
Poor coupling of technical
improvements with economic
feasibility and lifecycle cost-benefit
analysis (Nguyen et al., 2021).
Lack of studies addressing emission
compliance, hydrogen co-firing, and
carbon capture in captive plants in
low-income economies (Lopez et al.,
2019).
Insufficient integration of cost
models in technical simulations for
Australia, UAE
design selection or upgrade
justification (Farjana et al., 2020).
METHODOLOGY/MATERIAL
AND METHOD
Dangote Oil
Refinery
CCP
Information Logging
SCADA
Data
Collection
ASPEN HYSYS
Performance Evaluation
(See Table 1.1)
Method
Data to be
Collected/E
valuated
Field Observation
DSC
Simulation
Gas turbine HRSG,
Steam turbine
See Table 1.1
Process Flow
Diagram for
CCP
See Figure 1
Unit
Operation
See Table 1.1
• Overall Efficiency
• Environmental
Impact Assessment
Table 1.1: Data to be Collected and Evaluated
key components
Unit Operation







Performance Evaluation

Nitrogen (N₂)
Nitric Oxide(NO)
Nitrogen Dioxide(NO2)
Oxygen (O2)
Carbon Dioxide (CO₂)
Argon (Ar)
Methane (CH₄)
Ethane (C₂H₆)
Propane (C₃H₈)
Iso-butane (i-C₄H₁₀)
n-Butane (n-C₄H₁₀)
Iso-pentane (i-C₅H₁₂)
Hexane (C₆H₁₄)
Compressor
Combustor
Expander
Heat Exchanger
Cooler
Pump
Valve
Inlet and outlet temperatures and pressures

Mass flow rates

Heat duties

Shaft work or power output

Component efficiencies (thermal and mechanical)













Table 1.2: Compressed Air
The composition of the natural gas according to the
specifications given by Shoreham gas power plant is
given in Table 1.2
Component
Mole %
Nitrogen
0.890
CO2
2.000
Methane(CH4)
89.00
Ethane(C2H6)
7.000
Propane(C3H8)
1.000
Iso-butane (i-C₄H₁₀)
0.05
n-Butane (n-C₄H₁₀)
1.000
Iso-pentane (i-C₅H₁₂)
0.004
Hexane (C₆H₁₄)
0.001
Table 1.3: Composition of Atmospheric Air
Component
Mole %
Nitrogen
77.30
Oxygen
20.74
CO2
0.03
Argon
0.92
Process Flow Diagram for Combined Cycle Power Plant
Determination of Overall Efficiency
• The overall efficiency of the combined cycle plant will be calculated using the ratio of total net power output to total
energy input from fuel:
𝜂𝑜𝑣𝑒𝑟𝑎𝑙𝑙 =
𝑊𝐺𝑇 +𝑊𝑆𝑇 −𝑊𝑎𝑢𝑥
𝑄𝑓𝑢𝑒𝑙
2.1
• This will be compared against theoretical values for ideal cycles and industry benchmarks (typically 50–60%).
Environmental Impact Assessment
• The environmental performance of the plant will be assessed by estimating emissions such as CO₂ and NOₓ, based on
combustion data and emission factors. This will be done using either Aspen HYSYS' built-in environmental modelling
tools or supplementary emission calculation methods.
• Improvements in thermal efficiency will be correlated with emission reductions to evaluate the environmental benefits of
combined cycle integration.
EXPECTED RESULT
The proposed research is expected to yield the following outcomes, corresponding to the specific objectives of the study:
• Thermodynamic Performance Evaluation
• Simulation and System Validation Using Aspen HYSYS
• Overall Plant Efficiency Determination
• Environmental Performance Analysis
CONCLUSION
• The analysis of combined cycle power plant performance provides critical insight into the operational efficiency,
thermodynamic synergy, and practical feasibility of utilizing gas turbines, heat recovery steam generators (HRSGs),
and steam turbines in a unified power generation configuration. Through a structured methodology that incorporates
real-time data acquisition, simulation modelling, and thermodynamic evaluation, this study effectively underscores the
enhanced performance capabilities and energy utilization benefits of combined cycle systems.
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