Plant Thermal Efficiency Research Articles

Thermal Power Plant Performance Analysis by Estimating Boiler Efficiency via Indirect Method: A Case Study

The performance of power plants is very critical since it is directly related with operating and electricity production costs. Among the other different type of power plants, coal-fired ones have advantages such as reliability and low cost fuel. In this paper, a coal (lignite) fired thermal power plant having capacity of 160 MW is taken into consideration and the impact of condenser pressure, moisture content of lignite, excess air coefficient, efficiency of turbine pressure and heater numbers on power plant thermal efficiency is investigated. It is aimed to determine performance losses of each equipment by means of the thermodynamics and economic analysis. In this scope, it is expected that the power plant operator will be able to evaluate the reduction potential of equipment performance losses and ensure more effective use of the power plants by correctly planning the maintenance and rehabilitation needs and times. In the calculations, the boiler efficiency was determined with EN 12952-15 standard (indirect method) since this method has higher accuracy in coal fired boilers. It is seen that the condenser pressure and excess air coefficient increments have not significant impact on power plant efficiency compared to moisture content of lignite, excess air coefficient, efficiency of turbine pressure and heater numbers. The significant effect is observed for fuel moisture content which rises from 22% to 47% and the power plant efficiency falls from 40% to 28%. The variation of the power plant thermal efficiency in case of failure of heaters is investigated and the power plant efficiency has decreased from 40.17% to 36.09% when the pre-heaters are no longer in to be in use because of any reason. In addition, revenue losses are estimated for each main equipment efficiency reduction for better use of power plant capacities and electricity lowering production costs.

Power Generation Systems Assessment: A New Approach

Power generation systems have become useful for grid base and off grid electric power generation. Hence, its performance has become critical for sustainable growth and development. Performance evaluation of power generation systems has always been carried out using the independent assessment approach (IAA) whose models are: the reliability, availability, emission characteristics, energy and exergy efficiency. The IAA approach only assesses the system performance in part without recur to other indexes, hence, limiting a holistic view of the true plant state. In this paper, the development of a new performance index using the combined assessment approach (CAA) is explored. This approach (CAA) seeks to combine two relatable traditional measures for the assessment of power generation system. The model combines exergy efficiency and reliability measures for analysis. First Independent Power Limited (FIPL) gas turbine power plant was used to test the model. The plant reliability and availability were evaluated along with its thermal efficiency using the exergy model. The analysis of plant thermal efficiency was carried out using the steady state model. Results of the traditional indexes of the plant were compared with the proposed (Bassy-II index) index. It was seen that the new index provided a new assessment criteria. The exergy efficiency, reliability and availability measures indicated a fairly rated plant state. However, the new index defined a new plant state which is unique and represents the true status of the system in whole. Hence, the proposed index (Bassy-II index) is recommended for use in the holistic assessment of power generation systems.

Design of a Decision Support System for Power Plant Thermal Efficiency Management at PLTU X

Efficiency management is one of the important pillars of the asset management system implemented at PLTU X based on PJBS guidelines to manage the power plant reliably and efficiently, which can support realising the company's vision of becoming a trusted power plant manager in Southeast Asia. As with efficiency management functions in other lines, the aim of power plant efficiency management is also to reduce production costs and ensure that the plant can operate efficiently all the time by controlling thermal losses in the power plant cycle. Determining efficiency management recommendations is very necessary to minimise the level of thermal losses that occur in the power plant's thermal cycle after evaluation. There is a series of evaluation processes that must be carried out to determine recommendations for optimising generator efficiency management; however, the process is currently still manual and takes a long time. With the advantages of a decision support system, which is usually used in determining systematic strategic decisions, it is hoped that this design can help engineers determine steps based on recommendations produced by the system precisely and in real-time so that they can be executed immediately to increase the efficiency of power plants even more. optimal.

Energy efficiency enhancement of a thermal power plant by novel heat integration of Internal Combustion Engine, Boiler, and Organic Rankine Cycle

AbstractThe utilization of waste energy contributes to reducing carbon emissions and mitigating global warming. A novel heat integration system comprising an Internal Combustion Engine (ICE), Boiler, and Organic Rankine Cycle (ORC) coupling is techno‐economically examined in this study. The feasibility of waste heat recovery from industrial boilers of a thermal power plant (Gadoon Textile Mills Limited, Pakistan) having 2.66‐MW capacity was assessed. This was done by efficiently harnessing the waste heat from boiler exhaust gas by coupling an existing system with an ORC. A steady‐state simulation model of the ICE‐Boiler‐ORC system was developed through Power Plant Simulator and Designer (PPSD) software to perform a multiparametric study. Additional heat power (3710 kW) was extracted from the boilers' waste gases through ORC. Consequently, the overall plant thermal efficiency was enhanced from 61.84% to 82.68% and the overall net electric efficiency of the existing system was increased by 0.9%. The average payback period was found 4.2 years based on different plant operation scenarios and equipment prices (Chinese or European origin). Therefore, the proposed system holds significant technical and economic potential for enhancing energy efficiency through low‐grade waste heat and proves to be economically viable with a short payback period.

Economic evaluation of hydrogen production in second and third units of Bushehr nuclear power plant regarding future need of nuclear fission technology

Today, the most important challenge for hydrogen production is the use of suitable energy source for sustainable production. The dual use of nuclear power plants allows them to expand into other markets by eliminating greenhouse gas emissions from processes such as hydrogen production. The significance of this matter especially in countries with ongoing new nuclear power plants is high and shows the future need for nuclear fission technology. In this paper, an economic assessment of hydrogen production in the second and third units of the Bushehr nuclear power plant (BNPP) with the Hydrogen Economy Evaluation Program (HEEP) is carried out and a comparison of CO2 emission in nuclear and non-nuclear methods of hydrogen production is presented. Most nuclear reactors, including Advanced Pressurized WaterReactor (APWR), High Temperature Gas Reactor (HTGR), and Water-Water EnergeticReactor (WWER), can be used as a source of thermal and electrical energy for the process of hydrogen production. In this research, hydrogen production processes based on the Conventional Electrolysis (CE), High Temperature Steam Electrolysis (HTSE), and Sulfur-Iodine (SI) Process using different storage and transportation options are compared to choose the cost-effective method for coupling with the WWER1000 reactor. Hydrogen production, thermal energy, and electricity costs have been calculated and explained in detail. The results showed that the cost-effective option for hydrogen production is using the High Temperature Steam Electrolysis (HTSE) method, Compressed Gas (CG) storage, and pipeline transportation, by 2.88 $/kg. Also, applying this method to produce hydrogen, the nuclear power plant thermal efficiency, and the hydrogen plant efficiency are kept in the best possible conditions by 51.98% and 58.21%, respectively.

Energy and Exergy Analysis of 6 MW Gas Power Plant at BOB PT. Bumi Siak Pusako - Pertamina Hulu

BOB PT. Bumi Siak Pusako – Pertamina Hulu is Indonesian Operator Company that uses gas power plant for Pekanbaru Coastal Plan (CPP) block. The 4x6 MW energy capacities must follow energy, exergy, economics analysis and environmental impacts due to CO² emission and exhaust gas temperature. From the analysis, the gas power plant thermal efficiency is 42.85%, exegetic efficiency is 33.22% with the largest exergy loss of 18.7 kW in combustion chamber, 7.1 kW in compressor, and 2.69 kW in gas turbine with total cost loss due to exergy destruction of 2,537.52 $/hour. The cost loss value is 1362.45 $/hour for compressor, 1,962.28 $/hour for combustion chamber, and 212.79 $/hour for gas turbine. The exhaust emission is 0.21 kg/s, forest area required to absorb pollution is 11.63 ha, exhaust heat released is 1913.51 kW. This study indicates that the analytical method carried out can be developed and applied comprehensively to generating facilities in Indonesia.

Impact of core power density on economics of a small integral PWR

Increasing the core power density of nuclear reactors allows higher power generation from the same volume, reducing the cost of the plant. The lower power rating and higher degree of inherent safety for small modular reactors motivate exploring the highest achievable power density to improve their economics and overcome lack of economy of scale. Given the urgency to deploy carbon free energy sources in the near term, the current nuclear fuel supply must be adopted. Assuming standard 17x17 pressurized water reactor (PWR) fuel assemblies with enrichment below 5%, a parametric study on core power density of an integral PWR (iPWR) is performed. The reference core design is rated at 60 kW/L and composed of 77 reduced-height fuel assemblies. The reactivity control during normal operation is assumed to utilize soluble boron and fuel burnable poisons. The commercial STUDSVIK code package is used to design cores ranging from 20 kW/L to 170 kW/L. This range results in respective output powers between 50 and 420 MWe for an assumed 32% plant thermal efficiency. Core safety parameters, such as peaking factors, Minimum Departure from Nucleate Boiling Ratio and maximum fuel temperatures are evaluated for all designs. Simplified economic evaluation of lifetime-levelized unit costs for the fuel cycle, operation and maintenance and capital expenditures was performed as a function of power density. The relatively low core discharge burnup (32 MWD/kgU) leads to high lifetime-levelized fuel cycle unit cost for the reference core. However, increase in power density allows significant reduction in operation, maintenance and capital unit costs. Doubling power density resulted in 80% reduction in total levelized cost of electricity. The unique features of a forced circulation iPWR technology combined with compact steam generator technology could allow achieving high power densities (greater than 125 kW/L). Specific examples on relationship of cost and safety margins are also discussed.

Off-design model of an ORC system for waste heat recovery of an internal combustion engine

• ASPEN® HYSYS software, off-design cycle simulations were done to evaluate Organic Rankine Cycle performance; • Economic calculation, CEPCI based, evaluated the feasibility of plant implementation; • A technical and economic analysis for an Organic Rankine Cycle was performed. The exhaust gases of an ICE leave the equipment still with enough temperature to generate more electric power if a proper system is used for that purpose. Therefore, due to this scenario, in this work a study of an ORC system to recovery energy from the flow gases of a stationary diesel engine. The analyses are in three parts: (1) parametric analysis of an ORC system in on-design to determine the cycle's optimal operating point; (2) parametric analysis in off-design condition, to verify the behavior of power production and cycle efficiency when the heat source's flow and temperature are varied; (3) An economic analysis, a CEPCI based model was used. The system design was determined for a working fluid flow rate of 0.09 kg/s, evaporation and condensation pressure of 3,870 kPa and 25 kPa, respectively, and with exhaust gas at 420 °C and 0.1697 kg/s. For the off-design simulations, the evaporation pressure, the working fluid flow and the heat source inlet conditions were varied. A minimum, average, and maximum net power production of 8.56 kW, 15.59 kW, and 26.29 kW, respectively, was verified, while in the design condition it was 14.72 kW, there was also an average increase in exergy of 9.35%. The initial investment for the system's implementation is US$ 23,257.02 and the financial return and rate of return reach an average of 1.5 years and 90%, respectively. The study shows that the system increases the power plant's thermal efficiency and decreases fuel consumption as well as the emission of pollutant gases.

Techno-economic analysis of co-combustion of Indian coals with municipal solid waste in subcritical and supercritical based steam turbine power generating carbon-negative systems

Incineration of municipal solid waste (MSW) can generate thermal energy for electricity generation and reduces its accumulation in the environment. MSW has low calorific value and its utilization would lead to low thermal efficiency in power plants due to higher auxiliary power consumption. Alternatively, this problem can be overcome by co-utilizing MSW with coal in thermal power plants. The capture of the generated CO2 from MSW can lead to carbon-negative energy production. Hence to evaluate its feasibility, energy and techno-economic analysis of subcritical and supercritical based steam turbines using MSW and its co-utilization with Indian high ash and low ash coals are performed using Aspen plus software (v 8.8). The effect of integrating post combustion carbon capture on the net thermal efficiency of power plants and its subsequent impact on levelized cost of electricity (LCOE) are analysed. The feedstock with an equal proportion of coal and MSW had shown a reasonable LCOE in the range of 60–67 $/MWh without carbon capture. The results had shown that the addition of 25% MSW to low ash coal could give a similar plant thermal efficiency and LCOE to that of high ash coal under subcritical conditions without carbon capture.

Off-Design Dynamic Performance Analysis of a Solar Aided Coal-Fired Power Plant

Coal consumption and CO2 emissions are the major concerns of the 21st century. Solar aided (coal-fired) power generation (SAPG) is paid more and more attention globally, due to the lesser coal rate and initial cost than the original coal-fired power plant and CSP technology respectively. In this paper, the off-design dynamic performance simulation model of a solar aided coal-fired power plant is established. A 330 MW subcritical coal-fired power plant is taken as a case study. On a typical day, three various collector area solar fields are integrated into the coal-fired power plant. By introducing the solar heat, the variations of system performances are analyzed at design load, 75% load, and 50% load. Analyzed parameters with the change of DNI include the thermal oil mass flow rate, the mass flow rate of feed water heated by the solar energy, steam extraction mass flow rate, coal consumption, and the plant thermal efficiency. The research results show that, as DNI increases over a day, the coal saving rate will also increase, the maximum coal saving rate reaches up to 5%, and plant thermal efficiency reaches 40%. It is analyzed that the SAPG system gives the best performance at a lower load and a large aperture area.

Conversion of steam power plant into cogeneration unit - Case study

One of possible solutions leading to the increase of steam power plant thermal efficiency is its conversion into a cogeneration unit. However, it requires the heat recipient to be on-site and, if so, it may be done by implementation of absorption heat pump (AHP) technology with low temperature waste heat recovery and utilization. The paper presents results of an analysis of benefits resulting from implementation of absorption heat pump into the steam power plant for recovery of low temperature waste heat, due to additional demand for heat delivery to dedicated recipient (DHR). The demand for heat along the whole year was assumed and the calculations were performed for two cases. In the first case, which was called the reference case, the heat was produced by dedicated heat exchanger (DHX) fed with steam taken from the pipeline between the medium and low-pressure turbine sections (MPLPP). In the second case, absorption heat pump (AHP) as the main unit for heat production and recovery was assumed. However, due to insufficient heat production in some conditions, peak heat exchanger (PHX) placed directly behind the heat pump was considered. Both heat pump and pick heat exchanger were fed with steam taken from MPLPP, however, due to the AHP requirements the stem was mixed with hot water taken from hot water tank to achieve the steam saturation state. Results of calculations performed show that implementation of a heat recuperation by absorption heat pump implemented to conventional steam power plant increases the overall efficiency of cogeneration system, but at the same time it causes the electricity production to decrease. Moreover, the production of heat by absorption heat pump has lower impact on the electricity generation compared to generation of heat by conventional heat exchanger. If reference power plant without heat production is considered, due to the heat pump implementation the electricity production decreases of about 1.32% for heat production with dedicated heat exchanger, and of about 0.89% for absorption heat pump with peek heat exchanger respectively. It means that, owing to implementation of AHP instead of DHX with the same heat production, the power plant may generate more than 0.4% of total electricity produced.

Parametric Study on the Performance of Combined Power Plant of Steam and Gas Turbines

Abstract This paper deals with aspects of the combined power and power (CPP) plants. Such plants consist of two major parts: the steam turbine and gas turbine plants. This study investigates the efficiency of CPP under the effect of several factors. CPP plants including an open cycle gas turbine and a bottoming cycle steam turbine can achieve the highest thermal efficiency obtained with turbomachinery up to date. In this cycle, the anticipated waste thermal energy of the exhaust of gas turbine is used to generate high-pressure steam to empower the steam turbine in the steam cycle. By systematically varying the main design parameters, their influence on the CPP plant can be revealed. A comprehensive parametric study was conducted to measure the influence of the main parameter of the gas and steam cycles on the performance of CPP. The results exhibit that the overall plant thermal efficiency is significantly greater than that of either of the two turbines. Due to the high thermal efficiency, a significant reduction in the greenhouse effect can be achieved. It is found that the regenerative steam cycle will reduce the overall efficiency of the combined cycle. On the other hand, using the reheat steam cycle in the CPP plant will lead to an increase in both the thermal efficiency of the plant and the dryness factor of steam at the exit of the steam turbine.

Microchannel steam generators for design for integral inherently safe light water reactors

A steam generator design for the Integral Inherently Safe Light Water Reactor (I2S-LWR) based on microchannel heat exchanger (MCHX) technology is discussed. An experimentally validated heat transfer and pressure drop model is applied to the development of steam generator design for this LWR. The potential of MCHX technology to provide compact, high power density steam generators for integral inherently safe reactors is demonstrated. A Rankine cycle model for a system with a once-through MCHX steam generator is developed and the plant thermal efficiency is quantified. Heat transfer and pressure drop in the MCHX steam generator design for I2S-LWR is compared with those in a conventional tubular steam generator design. A simple exergy analysis is performed for two alternative I2S-LWR power cycles, the flash Rankine cycle and a Rankine cycle with once-through steam generation, to demonstrate the advantages of using an integral steam generator.

Turbo-Expander Generators for Supplemental Power Generation in LNG Liquefaction Plants

Incentives to increase efficiency and reduce CO2 emissions have led to the development of many plant process designs incorporating turbo-expanders. Turbo-expanders provide the most efficient solution when it is required to reduce the pressure of a fluid stream. By expanding high pressure fluid, energy in the high-pressure fluid entering the turbo-expander can be efficiently used for electrical power generation. The energy recovered from the expansion is supplementary, thereby improving the thermal efficiency of the plant without leaving any noticeable trace of greenhouse gas emissions. This article focuses on both mechanical and electrical considerations for the implementation of turbo-expander generators. In an example of LNG liquefaction plant, the article discusses the plant thermal efficiency, turbo-expander performance curve, generator sizing, and the choice between the induction and the synchronous generator. The impact on the plant real and reactive power balance and the system stability is shown in an example. Furthermore, this article evaluates the options for the turbo-expander generator tie-in points within the electrical system.

Thermal power plant upgrade via a rotating detonation combustor and retrofitted turbine with optimized endwalls

In the past decade, pressure gain combustion research has promised over 10 percentage-points of increase in power plant thermal efficiency. Alas, to realize such potential gain, one must effectively couple the turbine with the detonation combustor, whose exhaust conditions differ substantially from current state of the art gas turbines. This paper presents a modeling approach that enables a superior thermodynamic cycle with a rotating detonation combustor and a retrofitted gas turbine by including a diffuser downstream of the combustor and by contouring the turbine endwall, while preserving the airfoil geometry. We propose a multi-step optimization strategy, parametrizing the endwall geometry with a few control points, without altering the airfoil geometry, and with the stage turbine efficiency as objective function. In a first step the turbine performance is assessed with steady inlet conditions by solving the steady three-dimensional Reynolds-Averaged Navier-Stokes equations. In a second step, the inlet conditions are unsteady, as predicted from a detonation combustor and a diffuser, and three-dimensional full unsteady simulations are performed with an unsteady Reynolds-Averaged Navier-Stokes solver. By altering the vane endwall, the steady optimization yielded an efficiency increase of 12% relative to the baseline, while the unsteady optimization resulted in 21% increase compared to the datum turbine. Finally, a full engine analysis demonstrated the superiority of pressure gain combustion which included a realistic thermodynamic cycle of the combustor, the diffuser and the optimized turbine components.

Bio-CH4 from palm empty fruit bunch via pyrolysis-direct methanation: Full plant model and experiments with bio-oil surrogate

Abstract A promising, cleaner alternative process of thermochemical conversion of lignocellulosic biomass to biomethane is proposed and rigorously investigated via modelling and experiments for the first time. Using a conventional nickel on calcium aluminate catalyst, operated in bench scale at 1 atm, 400 °C, and with a feed molar steam to carbon ratio of 2, the Low Temperature Steam Reforming of acetic acid, representing a single compound bio-oil surrogate, achieves a promising 81.9% fuel carbon conversion to gases with a methane yield of 15.7 wt% of the feed. This compares to 21 wt% methane yield at equilibrium, thus demonstrating encouraging first time performance and scope for future catalyst optimisation. A comprehensive Aspen Plus model is developed for the first time for an industrial plant producing biomethane from palm empty fruit bunch (50 wt% initial moisture), an under-used agro-industrial waste produced in vast amounts in South-East Asia and Sub-Saharan Africa. Dependency on external heating is completely eliminated by heat recovered from combusting 25% of the gas product. Based on the simulation results of the autothermal plant, a final gas product consisting of 99.2 wt% of CH4 and 0.8 wt% of H2 is predicted with a plant thermal efficiency of 80.6%, i.e., comparable to modelled efficiencies found in the literature for wood gasification to biomethane plants that generate syngas as a necessary intermediate.

Energy-Exergy Analysis of Combined Reheating-Regenerative Rankine Cycle using Entropy Generation Principle

The growing attention towards the exergy analysis of thermal systems is identifying the cause of losses, to scale the process, and rectifying the components. In this paper, the thermodynamic (energy-exergy) analysis of combined reheating and regeneration based Rankine Cycle is carried out. The energy-exergy analysis has been established for the boiler, turbines, Feed heaters, condenser and pump majorly. The result of thermodynamic analysis is estimeted in terms of 42% of plant thermal efficiency, 70 % of steam generation unit efficiency (Economizer. Super heater), Maximum heat absorbed by economizer of plant as 39% is achieved, with 40TPH of coal consumption. Boiler, High Pressure Turbine, Intermediate Pressure Turbine, Super Heater have found best performance in analysis and Reheating-Regenerative rankine method improves 6-8% in thermal efficiency also. This analysis concluded that energy efficiency is greater than exergy efficiency which identifies the power plant utilities and further improvement for efficient power generation opportunities like waste heat recovery technology employment.

CFD and thermal-hydraulics analyses of liquid sodium heat transfer in 19-rod hexagonal bundles with scalloped walls

This paper presents the results of CFD and thermal-hydraulics analyses of liquid sodium heat transfer in 19 UN fuel rod hexagonal bundles with scalloped walls. These bundles are arranged in three concentric rings in the core of the Very-Small, Long-LIfe, and Modular (VSLLIM) nuclear reactor. The rods are arranged in a triangular lattice with P/d = 1.2 and the scalloped walls ensure same flow area per rod in the bundles, and hence the radial uniformly of the liquid sodium flow for enhanced thermal performance. The analyses investigate the effects of the reactor power, PRX (1.0, 5.0, and 10 MWth) and the fission power distributions in the UN fuel on the radial and axial distributions of the fuel temperatures as well as the axial and radial distributions of the liquid sodium temperature and flow velocity in the hottest bundle in the reactor core. The analyses also calculate the bundle friction factor, fb, and the local Nusselt number, Nu, of liquid sodium along the bundle. The effect of the numerical mesh refinement on the results convergence is also investigated. The obtained values of fb and the fully developed Nusselt at different reactor thermal powers are within ±8% and +0.5 of reported correlations based on extensive CFD and experimental databases. At PRX = 10 MWth, the maximum UN fuel temperature in the hottest bundle in the VSLLIM reactor core is quite low (∼811 K), which ensures almost full retention of fission products in the UN fuel and minimal fuel swelling. The corresponding average temperature of the liquid sodium exiting the reactor core is 752 K. This temperature is not only suitable for attaining high plant thermal efficiency (∼35–38%), but also compatible with the HT-9 steel cladding and core structure for the long operation lives of the VSLLIM reactor.

Power Plant Thermal Efficiency as a Regulatory Mechanism: Implications for Emission Rates and Levels

In August 2018, the U.S. Environmental Protection Agency (EPA) proposed a new policy – the Affordable Clean Energy rule – to reduce greenhouse gas (GHG) emissions from existing coal-fired electric generating units and power plants. The new rule establishes emissions guidelines, including heat-rate efficiency improvements, for states when developing plans to limit GHG emissions. Past studies have indicated that heat-rate efficiency improvements can increase electricity output, leading to a reduction in emissions rates and an increase in emissions levels – a rebound effect that can temper the emissions-reduction benefits of plant-level heat-rate efficiency. This study adds to the literature by examining data on the relationship of plant-level heat-rate efficiency on the rate and level of GHG emissions. We explored three different types of GHGs – carbon dioxide, methane, and nitrous oxide. Controlling for variation across operators, our results suggest that gains in heat-rate efficiency are associated with higher levels of all three pollutants. Specifically, we found that a ten percent increase in heat-rate efficiency led to an average seven-to-nine percent increase in the level of GHG emissions. Our analysis highlights the need to further study the full effects of heat-rate efficiency policies before such rules are enacted.

Thermodynamic analysis and life cycle assessment of supercritical pulverized coal-fired power plant integrated with No.0 feedwater pre-heater under partial loads

With ever increasing share of renewable energy sources in the electricity mix, pulverized coal-fired power plants (PCPP) have to participate in peak load regulations frequently and thus, they regularly operate under partial loads. The energy efficiency and eco-efficiency are both significantly affected by such operating patterns. Therefore, the present work aims to establish an overall concept for the estimation of environmental impacts from PCPP under nominal and partial loads with combined thermodynamic analysis and life cycle assessment (LCA) methodology. A 1000 MW supercritical PCPP was modeled using commercial simulation software (GSE for thermodynamic simulation and SimaPro for LCA analysis). Results indicated that global warming was the predominant environmental impact of PCPP, while ozone formation, acidification and eutrophication were also serious concerns attributed to NOx emissions in electricity generation process. The mechanisms of formation, migration and removal of different kinds of pollutant emissions significantly influenced the LCA results. Particularly, the total environmental impact potential considerably increased by approximately 90% under partial/low loads due to reductions in the plant thermal efficiency and NOx removal efficiency. A novel partial load No.0 feedwater preheating system driven by steam ejector was thus proposed for NOx reduction improvement. Operation optimization was carried out based on the guidelines of the LCA framework. It was found that the total environmental impact could be effectively reduced by up to 27.3%. Therefore, the implementation of the No.0 feedwater pre-heater was favorable for environmental performance improvement under partial/low loads.