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22 pages, 1008 KiB

Open AccessArticle

Monitoring of Thermal and Flow Processes in the Two-Phase Spray-Ejector Condenser for Thermal Power Plant Applications

by Paweł Madejski, Piotr Michalak, Michał Karch, Tomasz Kuś and Krzysztof Banasiak

Energies 2022, 15(19), 7151; https://doi.org/10.3390/en15197151 - 28 Sep 2022

Cited by 10 | Viewed by 1966

Abstract

The paper deals with the problem of accurate measuring techniques and experimental research methods for performance evaluation of direct contact jet-type flow condensers. The nominal conditions and range of temperature, pressure and flow rate in all characteristic points of novel test rig installation [...] Read more.

The paper deals with the problem of accurate measuring techniques and experimental research methods for performance evaluation of direct contact jet-type flow condensers. The nominal conditions and range of temperature, pressure and flow rate in all characteristic points of novel test rig installation were calculated using the developed model. Next, the devices for measurement of temperature, pressure and flow rate in a novel test rig designed for testing the two-phase flow spray ejector condensers system (SEC) were studied. The SEC can find application in gas power cycles as the device dedicated to condensing steam in exhaust gases without decreasing or even increasing exhaust gas pressure. The paper presents the design assumptions of the test rig, its layout and results of simulations of characteristic points using developed test rig models. Based on the initial thermal and flow conditions, the main assumptions for thermal and flow process monitoring were formulated. Then, the discussion on commercially available measurement solutions was presented. The basic technical parameters of available sensors and devices were given, discussed with details. Full article

(This article belongs to the Special Issue Control, Simulation, and Monitoring of Thermal Processes in Power Plants)

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17 pages, 6435 KiB

Open AccessArticle

Water Level Control in the Thermal Power Plant Steam Separator Based on New PID Tuning Method for Integrating Processes

by Goran S. Kvascev and Zeljko M. Djurovic

Energies 2022, 15(17), 6310; https://doi.org/10.3390/en15176310 - 29 Aug 2022

Cited by 6 | Viewed by 2317

Abstract

The paper presents an analysis of water-level control in a thermal power plant (TPP) steam separator. This control structure is vital for the entire plant’s stable, reliable, and efficient operation. This process belongs to processes with an integrator because it concerns a level-control [...] Read more.

The paper presents an analysis of water-level control in a thermal power plant (TPP) steam separator. This control structure is vital for the entire plant’s stable, reliable, and efficient operation. This process belongs to processes with an integrator because it concerns a level-control issue, and the control variable is the feedwater flow. Said industrial processes are challenging to control and apply standard methods for tuning the PID controller, so a new procedure has been proposed. A procedure for tuning a PID controller for integrating processes is proposed based on the IFOPDT model, obtained from the wide step response of the process. Based on the process parameters estimated, the tuning of the controller is proposed. Results from the TPP TEKO-B2 (350 MW) are presented as an experimental verification. Compared with standard tuning methods, better results are achieved in the form of rise time and disturbance elimination rate. A significantly less risky and faster experiment for parameter estimation and controller tuning is also obtained. In addition, one adjustable parameter is provided to select the relation between performance and robustness. This method can be applied to various industrial processes with an integrator. Full article

(This article belongs to the Special Issue Control, Simulation, and Monitoring of Thermal Processes in Power Plants)

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18 pages, 3094 KiB

Open AccessArticle

Multi-Model-Based Predictive Control for Divisional Regulation in the Direct Air-Cooling Condenser

by Zhiling Luo and Qi Yao

Energies 2022, 15(13), 4803; https://doi.org/10.3390/en15134803 - 30 Jun 2022

Cited by 5 | Viewed by 1502

Abstract

Flow distortions caused by ambient wind can have complex negative effects on the performance of direct air-cooling condensers, which use air as their cooling medium. A control-oriented model of the direct air-cooling condenser model, considering fan volumetric effectiveness and plume recirculation rate, was [...] Read more.

Flow distortions caused by ambient wind can have complex negative effects on the performance of direct air-cooling condensers, which use air as their cooling medium. A control-oriented model of the direct air-cooling condenser model, considering fan volumetric effectiveness and plume recirculation rate, was developed, and its linearization model was derived. The influences of fan volumetric effectiveness and plume recirculation rate on backpressure were analyzed, and the optimal backpressure was calculated. To improve both the transient performance and steady-state energy saving of the condenser, a multi-model-based predictive control strategy was proposed to divisionally adjust the fan array. Four division schemes of the direct air-cooling fan array constituted the local models, and in each division scheme, axial fans were divided into three groups according to the wind direction: windward fans, leeward fans, and other fans. The simulation results showed that the turbine backpressure can be increased by 15 kPa under the influence of plume recirculation and the reduction of the fan volumetric efficiency. The fan division adjustment strategy can achieve satisfactory control performance with switching rules. Full article

(This article belongs to the Special Issue Control, Simulation, and Monitoring of Thermal Processes in Power Plants)

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14 pages, 2508 KiB

Open AccessArticle

Entrained Flow Plasma Gasification of Sewage Sludge–Proof-of-Concept and Fate of Inorganics

by Vishwajeet, Halina Pawlak-Kruczek, Marcin Baranowski, Michał Czerep, Artur Chorążyczewski, Krystian Krochmalny, Michał Ostrycharczyk, Paweł Ziółkowski, Paweł Madejski, Tadeusz Mączka, Amit Arora, Tomasz Hardy, Lukasz Niedzwiecki, Janusz Badur and Dariusz Mikielewicz

Energies 2022, 15(5), 1948; https://doi.org/10.3390/en15051948 - 7 Mar 2022

Cited by 23 | Viewed by 3910

Abstract

Sewage sludge is a residue of wastewater processing that is biologically active and consists of water, organic matter, including dead and living pathogens, polycyclic aromatic hydrocarbons, and heavy metals, as well as organic and inorganic pollutants. Landfilling is on the decline, giving way [...] Read more.

Sewage sludge is a residue of wastewater processing that is biologically active and consists of water, organic matter, including dead and living pathogens, polycyclic aromatic hydrocarbons, and heavy metals, as well as organic and inorganic pollutants. Landfilling is on the decline, giving way to more environmentally friendly utilisation routes. This paper presents the results of a two-stage gasification–vitrification system, using a prototype-entrained flow plasma-assisted gasification reactor along with ex situ plasma vitrification. The results show that the use of plasma has a considerable influence on the quality of gas, with a higher heating value of dry gas exceeding 7.5 MJ/m_N³, excluding nitrogen dilution. However, dilution from plasma gases becomes the main problem, giving a lower heating value of dry gas with the highest value being 5.36 MJ/m_N³ when dilution by nitrogen from plasma torches is taken into account. An analysis of the residues showed a very low leaching inclination of ex-situ vitrified residues. This suggests that such a system could be used to avoid the problem of landfilling significant amounts of ash from sewage sludge incineration by turning inorganic residues into a by-product that has potential use as a construction aggregate. Full article

(This article belongs to the Special Issue Control, Simulation, and Monitoring of Thermal Processes in Power Plants)

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27 pages, 5975 KiB

Open AccessArticle

Thermodynamic Analysis of Negative CO₂ Emission Power Plant Using Aspen Plus, Aspen Hysys, and Ebsilon Software

by Paweł Ziółkowski, Paweł Madejski, Milad Amiri, Tomasz Kuś, Kamil Stasiak, Navaneethan Subramanian, Halina Pawlak-Kruczek, Janusz Badur, Łukasz Niedźwiecki and Dariusz Mikielewicz

Energies 2021, 14(19), 6304; https://doi.org/10.3390/en14196304 - 2 Oct 2021

Cited by 54 | Viewed by 6823

Abstract

The article presents results of thermodynamic analysis using a zero-dimensional mathematical models of a negative CO₂ emission power plant. The developed cycle of a negative CO₂ emission power plant allows the production of electricity using gasified sewage sludge as a main [...] Read more.

The article presents results of thermodynamic analysis using a zero-dimensional mathematical models of a negative CO₂ emission power plant. The developed cycle of a negative CO₂ emission power plant allows the production of electricity using gasified sewage sludge as a main fuel. The negative emission can be achieved by the use this type of fuel which is already a “zero-emissive” energy source. Together with carbon capture installation, there is a possibility to decrease CO₂ emission below the “zero” level. Developed models of a novel gas cycle which use selected codes allow the prediction of basic parameters of thermodynamic cycles such as output power, efficiency, combustion composition, exhaust temperature, etc. The paper presents results of thermodynamic analysis of two novel cycles, called PDF0 and PFD1, by using different thermodynamic codes. A comparison of results obtained by three different codes offered the chance to verify results because the experimental data are currently not available. The comparison of predictions between three different software in the literature is something new, according to studies made by authors. For gross efficiency (54.74%, 55.18%, and 52.00%), there is a similar relationship for turbine power output (155.9 kW, 157.19 kW, and 148.16 kW). Additionally, the chemical energy rate of the fuel is taken into account, which ultimately results in higher efficiencies for flue gases with increased steam production. A similar trend is assessed for increased CO₂ in the flue gas. The developed precise models are particularly important for a carbon capture and storage (CCS) energy system, where relatively new devices mutually cooperate and their thermodynamic parameters affect those devices. Proposed software employs extended a gas–steam turbine cycle to determine the effect of cycle into environment. First of all, it should be stated that there is a slight influence of the software used on the results obtained, but the basic tendencies are the same, which makes it possible to analyze various types of thermodynamic cycles. Secondly, the possibility of a negative CO₂ emission power plant and the positive environmental impact of the proposed solution has been demonstrated, which is also a novelty in the area of thermodynamic cycles. Full article

(This article belongs to the Special Issue Control, Simulation, and Monitoring of Thermal Processes in Power Plants)

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15 pages, 5790 KiB

Open AccessArticle

Forecasting of Heat Production in Combined Heat and Power Plants Using Generalized Additive Models

by Maciej Bujalski and Paweł Madejski

Energies 2021, 14(8), 2331; https://doi.org/10.3390/en14082331 - 20 Apr 2021

Cited by 11 | Viewed by 2489

Abstract

The paper presents a developed methodology of short-term forecasting for heat production in combined heat and power (CHP) plants using a big data-driven model. An accurate prediction of an hourly heat load in the day-ahead horizon allows a better planning and optimization of [...] Read more.

The paper presents a developed methodology of short-term forecasting for heat production in combined heat and power (CHP) plants using a big data-driven model. An accurate prediction of an hourly heat load in the day-ahead horizon allows a better planning and optimization of energy and heat production by cogeneration units. The method of training and testing the predictive model with the use of generalized additive model (GAM) was developed and presented. The weather data as an input variables of the model were discussed to show the impact of weather conditions on the quality of predicted heat load. The new approach focuses on an application of the moving window with the learning data set from the last several days in order to adaptively train the model. The influence of the training window size on the accuracy of forecasts was evaluated. Different versions of the model, depending on the set of input variables and GAM parameters were compared. The results presented in the paper were obtained using a data coming from the real district heating system of a European city. The accuracy of the methods during the different periods of heating season was performed by comparing heat demand forecasts with actual values, coming from a measuring system located in the case study CHP plant. As a result, a model with an averaged percentage error for the analyzed period (November–March) of less than 7% was obtained. Full article

(This article belongs to the Special Issue Control, Simulation, and Monitoring of Thermal Processes in Power Plants)

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Review

Jump to: Research

31 pages, 2963 KiB

Open AccessReview

Direct Contact Condensers: A Comprehensive Review of Experimental and Numerical Investigations on Direct-Contact Condensation

by Paweł Madejski, Tomasz Kuś, Piotr Michalak, Michał Karch and Navaneethan Subramanian

Energies 2022, 15(24), 9312; https://doi.org/10.3390/en15249312 - 8 Dec 2022

Cited by 10 | Viewed by 9211

Abstract

Direct contact heat exchangers can be smaller, cheaper, and have simpler construction than the surface, shell, or tube heat exchangers of the same capacity and can operate in evaporation or condensation modes. For these reasons, they have many practical applications, such as water [...] Read more.

Direct contact heat exchangers can be smaller, cheaper, and have simpler construction than the surface, shell, or tube heat exchangers of the same capacity and can operate in evaporation or condensation modes. For these reasons, they have many practical applications, such as water desalination, heat exchangers in power plants, or chemical engineering devices. This paper presents a comprehensive review of experimental and numerical activities focused on the research about direct condensation processes and testing direct contact condensers on the laboratory scale. Computational Fluid Dynamics (CFD) methods and CFD solvers are the most popular tools in the numerical analysis of direct contact condensers because of the phenomenon’s complexity as multiphase turbulent flow with heat transfer and phase change. The presented and developed numerical models must be carefully calibrated and physically validated by experimental results. Results of the experimental campaign in the laboratory scale with the test rig and properly designed measuring apparatus can give detailed qualitative and quantitative results about direct contact condensation processes. In this case, the combination of these two approaches, numerical and experimental investigation, is the comprehensive method to deeply understand the direct contact condensation process. Full article

(This article belongs to the Special Issue Control, Simulation, and Monitoring of Thermal Processes in Power Plants)

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21 pages, 4589 KiB

Open AccessReview

Methods and Techniques for CO₂ Capture: Review of Potential Solutions and Applications in Modern Energy Technologies

by Paweł Madejski, Karolina Chmiel, Navaneethan Subramanian and Tomasz Kuś

Energies 2022, 15(3), 887; https://doi.org/10.3390/en15030887 - 26 Jan 2022

Cited by 255 | Viewed by 31508

Abstract

The paper presents and discusses modern methods and technologies of CO₂ capture (pre-combustion capture, post-combustion capture, and oxy-combustion capture) along with the principles of these methods and examples of existing and operating installations. The primary differences of the selected methods and technologies, [...] Read more.

The paper presents and discusses modern methods and technologies of CO₂ capture (pre-combustion capture, post-combustion capture, and oxy-combustion capture) along with the principles of these methods and examples of existing and operating installations. The primary differences of the selected methods and technologies, with the possibility to apply them in new low-emission energy technologies, were presented. The following CO₂ capture methods: pre-combustion, post-combustion based on chemical absorption, physical separation, membrane separation, chemical looping combustion, calcium looping process, and oxy-combustion are discussed in the paper. Large-scale carbon capture utilization and storage (CCUS) facilities operating and under development are summarized. In 2021, 27 commercial CCUS facilities are currently under operation with a capture capacity of up to 40 Mt of CO₂ per year. If all projects are launched, the global CO₂ capture potential can be more than ca. 130–150 Mt/year of captured CO₂. The most popular and developed indicators for comparing and assessing CO₂ emission, capture, avoiding, and cost connected with avoiding CO₂ emissions are also presented and described in the paper. Full article

(This article belongs to the Special Issue Control, Simulation, and Monitoring of Thermal Processes in Power Plants)

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