Feedwater Heater Research Articles

Application of a Two-Stage Steam Jet Injector Unit for Latent Heat Recovery of a Marine Steam Turbine Propulsion Plant

The paper presents the results of the numerical research of the steam jet injector applications for the regenerative feed water heating systems of marine steam turbine propulsion plants. The analysis shows that the use of a single injector for a single heat exchanger results in a relative increase in the thermal efficiency of the plant by 0.6–0.9%. The analysis also indicates the legitimacy of the usage of multistage feed water heating systems, which would enable the operating parameters optimization of the injectors. The obtained steam pressure up to the value of 1.8 barA allows for the heating of the feed water up to 110 °C. For higher degrees of feed water heating in the heat exchangers, it is necessary to supply heating steam of higher pressure. Therefore, the usage of two-stage steam jet injector units was considered advisable for the analyses.

Estimation of the efficiency of combining a npp with a hydrogen facility under conditions of safe use of hydrogen in a steam turbine cycle

THE PURPOSE. System efficiency and competitiveness assess of a new scheme for combining a nuclear power plant with a hydrogen complex based on additional heating of feed water and superheating of live steam in front of the high-pressure cylinder of a steam turbine. METHODS. Basic laws of thermodynamics were applied when developing and substantiating a new scheme for combining a nuclear power plants (NPP) with a hydrogen facility; theoretical regularities were applied of heat engineering; basic regularity were applied of fatigue wear of power equipment and assessment of its working resourse; basic regularities were applied for the assessment of operating costs and net present value (NPV). RESULTS. A new scheme is presented of the combination of a nuclear power plant with a hydrogen facility and a description of its operating principle on the example of a two-circuit nuclear power plant with a VVER-1000 reactor and a C-1000-60 / 1500 turbine. The data are presented on an increase in the productivity of steam generators at nuclear power plants with additional heating of feed water in the range of 235-250 ° C from its nominal value of 230 ° C. The temperature was estimated of live steam superheat depending on the temperature of the additional heating of the feed water. The results are presented of the calculation of the generated peak power by the power unit and the efficiency of conversion of the night off-peak power of the NPP into peak power, as well as the efficiency of the power unit of the NPP depending on the temperature of additional heating of the feed water. Main regularities are given for taking into account the fatigue wear of the main equipment of the hydrogen facility, including the rotor of the NPP turbine in the conditions of the stress-cyclic operation. The results are presented of assessing the cost of peak electricity NPP in combination with a hydrogen facility in comparison with a pumped storage power plant (PSPP) both for the current period and for the future until 2035. CONCLUSION. Hydrogen facility efficiency and competitiveness depends significantly on the intensity of the use of the main equipment in the conditions of the intense-cyclic operation. The hydrogen facility will competitiveness noticeably increase in comparison with the PSPP in the future. Efficiency of the NPP power unit and NPV is highest when the feed water is heated to 235 ° C and superheating of live steam in front of the high-pressure cylinder of the C-1000-60/1500 turbine up to 470°C.The hydrogen facility competes with the PSPP with her specific capital investment at the level of 660 USD / kW, provided that the boosting capabilities of the turbine are used with live steam overheating at 300 ° C and additional heating of feed water to 235°C on the current period. The PSPP does not compete with the hydrogen facility both for the current period and in the future with her specific capital investment of $ 1,500 / kW and above.

New procedure for optimal solar repowering of thermal power plants and integration with MSF desalination based on environmental friendliness and economic benefit

Using solar collectors to repower steam power plants is one of the cheapest methods to improve these power generation sites' technical, economic, and environmental performance. In this paper, using a comprehensive method based on economic benefits and environmental friendliness, solar collectors are designed to parallel with the feedwater heaters to repower the steam power plant. Also, an MSF desalination unit has been used to simultaneously generate power, heat, and freshwater in the repowered cycle due to the proximity of the studied steam power plant to the sea. Transient thermodynamic, exergy, economic, and environmental analyzes have been used to demonstrate performance improvements due to solar repowering. Results show that due to proper solar radiation at the site of the steam power plant, more use of solar collectors or solar factors equal to one lead to the highest economic benefits and the highest reduction in environmental impact. The solar collectors are also designed based on solar factors equal to one. The first scenario of repowering generates between 330 and 400 MW of power during the year. But in the second scenario, due to the consumption of the part of the cycle steam in the MSF unit, the amount of power generation in most months is about 310 MW. In the first and second scenarios of repowering compared to the base steam power plant, the total cost is reduced by an average of 50% and 41%, respectively. The total environmental impacts in the first and second scenarios of the repowering have been reduced by 30% and 22%, respectively, about the steam cycle. The mass flow of freshwater produced in this unit will be 115.4 kg/s. The performance ratio of the MSF unit will be 8.8, and the gain output ratio will be 9.62. The price of freshwater produced in this unit will be $0.21 per cubic meter of desalinated water.

Experimental Study of Concentrated Solar Power on Heat Feed Water Heaters in Steam Power Plants in Iraq

For generating power, solar energy is counted a good exporter. Iraq is located in a hot zonewith latitude from 32 degree N to 36 degree N. In Iraq, the average solar radiation is about 7kilowatt hours / day.In this work, central receiving tower was used to obtain steam using the available solar energyin summer and winter. To heat the feed water heater of South Baghdad Electrical Steam PowerPlant, steam utilization for this purpose. In the project, manufacturing the central receivertower, which is consisting of 150 mirrors fixed upon 75 manual tracking heliostats arranged forutilization the solar radiation concentrated on the central receiving tank (CRT). Pipes systemswere used for hot water or steam exits from receiver. In this study, the central receiver tank(0.5m*1m) was filled with 157 liter of water. The experimental work was run for one yearfrom June 2015 – May 2016. The outlet temperature of water from central tower receiver wassteam for (July and August 2015) and hot water with high temperature for other months of theyear. The results obtained from our system, solar shares for heating the feed water heater ofSouth Baghdad Electrical Steam Power Plant up to 1.86 % and an annual average of 1.03%.Temperature, power concentration factor and system efficient are greatly influenced by thenumber of heliostats used. A sample of calculations is used to evaluate the mathematical dataof hot water and steam temperatures obtained from this study. These values are approximatewith experimental data when compared together.

A study on steam cycle optimization for integrating energy storage system to nuclear power plant

As the share of renewable energy will be increasing, there is a growing interest in flexible power sources and energy storage systems due to the intermittent nature of renewable energy. We propose the Energy Storage System (ESS) integrated Nuclear Power Plant (NPP) as a solution. The system operates on load-following by branching the mass flow from the steam cycle to the ESS without changing the reactor thermal output. However, the merging point can be different for heat storing ESS and work storing ESS because the outlet conditions of the ESS vary depending on the type of ESS. In this study, the merging points are categorized into two types, feedwater heater and condenser. At each merging point, cycle optimization is performed while increasing the branch flow into ESS. The optimization goal is to maintain the feedwater temperature at the inlet of a steam generator. The power output and energy delivered to the ESS according to the merging point are estimated. From this study, it was found that when 25% of the inlet mass flow rate to the low-pressure turbine is diverted to ESS, the overall output of the steam cycle is decreased by 44.17% for the heat conversion ESS and 49.95% for the work conversion ESS.

Modeling and Simulation for multivariable Chemical System in Semadco Urea-Plant.(Dept.E)

For target or stabilizing the operation of ammonia converter R-107 is Semadco CTALKHA II Fertilizer Company that is by designing appropriate control system for the HP BFW heater E-127 CHigh Pressure Boiler Feed Water heater) which governs the system inlet temperature; It is very important to construct a mathematical model which simulates perfectly the practical system construction and operation, Such a model is not clearly and accurately presented in references. So; this work deals with formulating and constructing suitable mathematical model for this E -127 heater. The modeling procedure is based on dividing the chemical system into subsystems coupled through boundary conditions. The suggested mathematical model is tested numerically by computing the system open loop performances, which are then compared with the recorded experimental performances from the field. The results obtained show good agreement between both of the suggested model and the physical system.

An exergetic investigation of hot windbox and feedwater heating systems as repowering options for thermal power plants

ABSTRACT Repowering of worn-out coal-fired power plants is an alternative regarding costs and efficiency due to both increased installed capacity and reduced emissions per installed power. The exergy approach in examining repowering alternatives can provide data for designers and operators in the identification and comparison of losses. In this study, hot windbox (HWB) and feedwater heating (FWH) repowering alternatives are compared in terms of exergy for a coal-fired thermal power plant. The design data (Case 1) of the existing Soma-A Thermal Power Plant (Manisa, Turkey, with 44 MWel capacity) are used for energy and exergy calculations to investigate irreversibilities in the cycle and these calculations are repeated for each repowering option, FWH (Case 2), and HWB (Case 3). Energy simulations are performed by THERMOFLEX software, and exergy simulations are performed with a user-defined EXCEL calculation tool, in which the related first and second law equations are embedded, by using THERMOFLEX results of Soma-A. The total exergy destruction rate is increased after repowering applications by 22.5% after FWH repowering and 22.4% after HWB repowering. However, the total exergy destruction per installed power is decreased by 15.1% and 13.8%, and exergy efficiency is increased from 29.1% to 33.9% and 34.7% after FWH and HWB repowering applications, respectively. Also, CO2 emissions per installed power for the current power plant is decreased by 17.0% and 13.5% kg per kWhel after FWH and HWB repowering, respectively. Repowering alternatives have a significant impact on existing thermal power plants in terms of both energy efficiency and environmental impact. For this reason, it is one of the most powerful applications for short-term carbon emissions reduction by supporting these practices with various economic incentives to meet the ever-increasing energy demand.

Innovative hybrid solar-waste designs for cogeneration of heat and power, an effort for achieving maximum efficiency and renewable integration

In the present study, innovative energy efficiency enhancement methods and cleaner production in conventional waste-fired CHP plants are presented. This includes the medium- and low-grade solar thermal systems and flue gas condensation for feedwater heating in different arrangements. The article presents a thorough thermodynamic, economic, and environmental assessment of all the possible scenarios and then ranks the best solutions in different aspects. For making the results reliable, the solutions are applied to a waste-fired CHP plant in Denmark. For this, a transient simulation of the proposed configurations is performed via TRNSYS software for an entire year. The results indicate that the proposed models can produce more power and heat than the conventional plant but with different effectiveness factors. According to the economic results, a design consisting of a flue gas condensation circuit and parabolic trough collectors for the open and closed feedwater heater form the best configuration. The exergy assessment results indicate that the waste incinerator with annual irreversibility of 128.4 GWh is the most important component exergetically. Finally, the parametric study results show that the increase of incineration temperature significantly affects the power and heat exergy efficiency ratios.

Thermal Analysis of Waste Heat Recovery Systems Using CFD

The project statement is to optimize the heat transfer in a compact heat recovery unit (Heat Recovery and Emission Control Equipment - HREC) using CFD with application in day to day life. In general, the outgoing exhaust gasses are released to atmosphere at over temperature of the dew point of water vapor in waste gases. Recovering a portion of the waste heat enhances the efficiency of the equipment and as well reduce the emissions providing energy savings and green environment. In this study, the potential of recovering waste heat emitted by any heat generation units in common day to day life and in industry is considered. The Heat Recovery and Emission Control Equipment (HREC) acts an intermediate unit at the exit of hot gas generation unit & feed water heating unit. As a result of the calculation, it was determined that recovery of the waste heat can be employed at many applications as like as a combustion air preheater by means of a recuperator.

Simulation of Effects Off Service Closed Feedwater Heater on Steam Power Plant Performance Using Cycle Tempo 5.0

Steam power plant needs three important things in its operation, they are safety, reliability, and efficiency. Steam power plant efficiency can be elevated by installing regenerative feedwater heater. Feedwater heater is used to increase the temperature of water needed for combustion process in the boiler, therefore minimizing the fuel used in boiler. Case study is taken from PT. PJB UP Muara Karang Steam Power Plant unit 4 and 5. HPH 4 off service in August 2018 caused thermal efficiency drop about 1.86 % from the previous month. The same case was found in January 2019, in which HPH F off service caused 0.68 % from the previous month. This study’s aim is to find out the effect of off service closed feedwater heater to steam power plant performance using Cycle Tempo 5.0. Steam power plant unit 5 with 172 MW load is modelled on Cycle Tempo. Validation is done by comparing some parameter of simulation result to performance test result with 5% error tolerance. Few variation off service feedwater heater conditions are done by regulating valve for line bypass in order to set feedwater flow into tubes as well as drain flow. NPHR analysis is done by gathering net power and heat needed in boiler for each variation. The result obtained from this study shows that off service feedwater heater cause NPHR enhancement. The highest NPHR increase is achieved when HPH F is on off service condition, with value about 30.58 kCal/kWh. Off service HPH has bigger effect on NPHR increase than LPH on the same condition. Steam power plant efficiency increase continuously with the greater amount of operating feedwater heater. 3 LPH and 2 HPH usage on steam power plant with 172 MW load is assessed as adequate efficient, with all feedwater heater operating at 33.39 %.

Exergy and Energy Analysis of CFPP

Energy and exergy analysis of Pulverized Coal Fired Subcritical Power Plant (CFPP) performed to assess power plant performance and identify major losses both energy and exergy term. It’s found that, based on energy analysis, major losses occur in condenser, moisture in coal and steam turbine. While exergy analysis result that most exergy losses and destruction was in boiler and feedwater heater. Energy efficiency of boiler on 250MW, 300MW and 380MW was 68.56%, 69.56% and 72.42% respectively while exergetic efficiency was 52.81%, 56.33% and 57.39% respectively.

Transient and troubleshoots management of aged small-scale steam power plants using Aspen Plus Dynamics

This study is motivated by the insufficient studies on the dynamic simulation, operation control optimization, and operation strategies for small-scale old plants. In such small power plants, there is a need for cautions and stability during various troubleshoots. This study aims at developing a simulation model that accurately predicts the behavior of small-scale real plants under various part loads and troubleshoots. The actual operation of a 110-MW steam power-plant was modeled using Aspen Plus Dynamics, which employs a single-input single-output proportional integral (PI) controller. The controller tuning constants, K and IT, were optimized, and operation strategies for handling five troubleshoots are proposed. The simulation results are in good agreement toward the measured values, with a maximum relative error of 2%. The recommended operation strategies could prevent plant trip and return to steady state in a maximum of 5 min when two different halts are mimicked. Full-load thermal efficiencies of 94%, 97.9%, 92.6% were achieved when four burners were shutdown, high-pressure feedwater heaters tripped, and all the heaters tripped, respectively. The simulation presents the possibility of stabilizing the old power plants operation with maximum possible efficiency under various conditions. An updated operation and troubleshoot manual can be provided for various circumstances.

An Investigation of Hybrid Solar-Steam Power Plant: A case study in Iraq

In this work integrating Al-Zubaydia (Kut-Iraq) thermal power plant with solar thermal system is studied for heating feed water by solar energy to reduce fuel consumption and greenhouse gases emission. A closed type Parabolic Trough Solar Collector (PTSC) is designed, constructed, instrumented, and tested. Its thermal characteristics are reported under Iraq climate conditions for the period extended from June, to September 2017. The collector heat gain, efficiency, absorber temperature and heat exchanger effectiveness (considered as feed water heater) were presented for absorber side flow rates of (0.15, 0.2, 0.3, 0.4, 0.5) lpm of water or oil), and shell side water flow rates of (0.4, 0.5, 0.6lpm). Results show that the maximum obtained thermal efficiency of parabolic trough solar collector was 83.33% for oil working fluid. The maximum obtained oil outlet temperature was 106 oC at solar noon for (0.15) lpm. Theoretical results showed that the fuel save mode needs collector area of (32842 m2), while that needed for power boosting is (102569 m2) for the same thermal cycle efficiency. The fuel save mode reported a reduction in greenhouse emission.

Optimization of Thermal Conditions of Heat Recovery Boilers with Regenerative Heating in the High-Temperature Section of Isoamylene Dehydrogenation

Improving the efficiency of use of energy resources at large-capacity energy-consuming enterprises in the petrochemical industry in conditions of high internal and external competition is the priority for the development of the fuel and energy industry. This is confirmed by various legislative acts, including the energy strategy of the Russian Federation for the period up to 2035. This research focuses on a high-temperature section of dehydrogenation of isoamylenes into isoprene, the production of which relates (isoprene production relates to large petrochemical enterprises that consume a huge amount of energy resources) to large-capacity energy-consuming industries. To increase the thermodynamic efficiency of the research object, regenerative feedwater heating for heat recovery boilers is proposed due to deeper cooling of fuel and contact gas (the term "contact gas" is used in the technological regulations of an isoprene production company), which are secondary thermal energy resources in this technology. In accordance with the industry’s technology regulations, a block diagram of the initial and improved high-temperature section with the indication of material flows (The term "material flow" refers to the type of substances that are used in the high-temperature dehydrogenation stage of isoamylenes) was developed. The balance equations of the section under consideration are provided, and the thermal efficiency and exergy efficiency for systems utilizing fuel and contact gas are determined. The estimated economic effect was determined in physical terms; it was found to be 2008.58 toe/h. An exergy flow diagram is also provided to show how the system utilizes contact gas.

RAM analysis and availability optimization of thermal power plant water circulation system using PSO

This paper presents reliability, availability, and maintainability (RAM) analysis framework for evaluating the performance of a circulation system of water (WCS) used in a coal-fired power plant (CFPP). The performance of WCS is evaluated using a reliability block diagram (RBD), fault tree analysis (FTA), and Markov birth–death probabilistic approach. In this work, the system under study consists of five subsystems connected in series and parallel configuration namely condensate extraction pump (CEP), low-pressure feed water heater (LPH), deaerator (DR), boiler feed pump (BFP), high-pressure feed water heater (HPH). The reliability block diagram (RBD) and fault tree approach (FTA) have been employed for the performance evaluation of WCS. The Markov probabilistic approach based simulation model is developed. The transition diagram of the proposed model represented several states with full working capacity, reduced capacity, and failed state. The ranking of critical equipment is decided on the basis of criticality level of equipment. The study results revealed that the boiler feed pump affects the system availability at most, while the failure of deaerator affects it least. The availability of the system is optimized using the particle swarm optimization method. The optimized availability parameter (TBF, TTR) based modified maintenance strategy is recommended to enhance the availability of the plant system. The optimized failure rate and repair rate parameters of the subsystem are used to suggest a suitable maintenance strategy for the water circulation system of the thermal power plant. The proposed RAM framework helps the decision-makers to plan the maintenance activity as per the criticality level of subsystems and allocate the resources accordingly.

Thermodynamic analysis of coal-fired power plant based on the feedwater heater drainage-air preheating system

As coal-fired power plants are the main source of coal consumption, their energy generation efficiency needs to be improved urgently. One of the main reasons for irreversible energy loss in coal-fired power plants is the mismatched energy levels. To reduce the irreversible energy loss and improve the generation efficiency, the thermodynamic system of the coal-fired power plant needs to be optimized. In this work, a mathematical model of thermodynamic system has been established based on balance principles of mass and energy, which has been validated by design values of a 600 MW coal-fired power plant. Meanwhile, a novel air preheating system based on the feedwater heater drainage has been proposed, to utilize energy from the steam turbine extraction and boiler flue gas. Compared with the conventional schemes, the power supply efficiency of this optimized scheme improved by 1.7%, the coal consumption reduced by 13.1 g/kWh, and the generation cost reduced by 1.85 $/MWh. This work provides an accurate mathematical model for the thermodynamic system of a thermal power plant and an effective optimization method for improving the generation efficiency of a coal-fired power plant.

Pipe Designs of the Closed Feedwater Heater Rankine Cycle Power Plant

How to lower global energy consumption and improve energy conversion efficiency remains a major challenge in the fields of science and technology. Scientists have done tremedous work to save energy. For example, scientists have improved and designed the different parts of heating systems to make it approach the thermal idealized cycle, in order to increase the waste-heat utilization rate and convert heat into other forms of useable energy. After thorough study of the Closed Feedwater Heater (FWH) Rankine Cycle power plant, this paper shows two possible designs to increase energy efficiency: the Cylinder and Sphere Feedwater Heater, and the Pipeline Mini Turbine. Compared with the old system components, they convert steam’s kinetic energy into usable electricity or other forms of energy and reduce the waste of energy caused by temperature differences and circulations. As a result, they increase the heat transfer efficiency between water and steam in the feedwater heater and save more money because of the reused component.

Investigation of the regulatory range expansion at Krasnodar combined heat and power plant due to the partial displacement of regenerative extractions of the K-150-130 unit by steam from the backpressure turbine

The article describes a new way to increase the technical maximum load of Krasnodar CHPP. It involves the joint operation of block part turbo generators and additionally installed backpressure turbine with the displacement of steam extraction to high pressure regenerative heaters. We provided a detailed overview of the power plant equipment. We calculated the effectiveness of joint operation and shutdown of the high pressure feed water heater (HPFH) 1, 2. It showed that when implementing the proposed technical solution, the power increase in the technical maximum mode for each unit amounted to 7.8 MW. The total increase in the power plant is 43.6 MW. The joint operation scheme allows to increase the technical maximum of the power plant with higher energy efficiency: the specific consumption of reference fuel for electricity generation is 4 g r.f./kW*h, lower than when the HPFH 1, 2 is turned off. The economic effect of the applied solution was estimated for Krasnodar CHPP conditions. It was shown that the annual increase in net profit amounted to 33.7 million rubles, and the payback period of investments is 4.7 years.

A Stacked Denoising Sparse Autoencoder Based Fault Early Warning Method for Feedwater Heater Performance Degradation

Power grid operation faces severe challenges with the increasing integration of intermittent renewable energies. Hence the steam turbine, which mainly undertakes the task of frequency regulation and peak shaving, always operates under off-design conditions to meet the accommodation demand. This would affect the operation economy and exacerbate the ullage of equipment. The feedwater heater (FWH) plays an important role in unit, whose timely fault early warning is significant in improving the operational reliability of unit. Therefore, this paper proposes a stacked denoising sparse autoencoder (SDSAE) based fault early warning method for FWH. Firstly, the concept of a frequent pattern model is proposed as an indicator of FWH performance evaluation. Then, an SDSAE- back-propagation (BP) based method is introduced to achieve self-adaptive feature reduction and depict nonlinear properties of frequent pattern modeling. By experimenting with actual data, the feasibility and validity of the proposed method are verified. Its detection accuracy reaches 99.58% and 100% for normal and fault data, respectively. Finally, competitive experiments prove the necessity of feature reduction and the superiority of SDSAE based feature reduction compared with traditional methods. This paper puts forward a precise and effective method to serve for FWH fault early warning and refines the key issues to inspire later researchers.

Advanced Energy, Exergy, and Environmental (3E) Analyses and Optimization of a Coal-Fired 400 MW Thermal Power Plant

AbstractIn this article, energy, exergy, and environmental (3E) analysis of a 400 MW thermal power plant is investigated. First, the components of the power plant are examined in terms of energy consumption, and subsequently the energy losses, exergy destruction, and exergetic efficiency are obtained. It is shown that the highest energy losses are in the closed feedwater heaters Nos. 1 and 5 and the boiler with amounts of 7.6 × 10 J/s and 6.5 × 107 J/s, respectively. The highest exergy destruction occurs in the boiler and amounts to 4.13 × 108 J/s. The highest exergetic efficiency is 0.98 and is associated with the closed feedwater heaters Nos. 4 and 8. It is observed that the exergetic efficiency and exergy destruction in the boiler are the primarily affected by changes in the environmental temperature. Furthermore, by increasing the main pressure in the turbine, the load on the power plant is increased, and increasing the condenser pressure reduces the load on the power plant. In an environmental analysis, the production of pollutants such as SO2 production and CO2 emission has been investigated.