Papers by Keyword: Thermal Power Plant

Abstract: The availability of electrical energy is essential for human progress and economic development. Renewable energy solutions, including waste-to-energy (WtE) systems, present sustainable alternatives but require advanced control strategies for optimal performance. This research aims to enhance the control of drum level, temperature, and pressure in WtE steam boilers at Ethiopia's Reppie power plant. The existing Programmable Logic Controller (PLC) system is limited in its ability to predict future states and handle nonlinear system behaviors. To overcome these challenges, a Radial Basis Function Autoregressive with Exogenous input (RBF-ARX) model was developed and integrated with a Model Predictive Controller (MPC). The results demonstrate that the MPC approach significantly surpasses the performance of the Linear Quadratic Regulator (LQR) in terms of control efficiency. For temperature control, the MPC achieves a settling time of 0.3955 seconds and a rise time of 0.0195 seconds, compared to LQR's 5.99 seconds. Similarly, for pressure control, the MPC achieves a settling time of 0.6678 seconds, outperforming the LQR's 12.507 seconds. Drum level regulation further showcases the superiority of MPC, with a settling time of 0.5223 seconds versus the LQR's 8.302 seconds. This proposed RBF-ARX-based MPC framework not only optimizes control efficiency at Reppie but also demonstrates scalability and applicability to other WtE plants, enhancing operational performance under varying conditions. MATLAB/Simulink was used for the modeling and simulation, confirming the robustness of this approach for global adoption in WtE systems.

Abstract: The author analyzed technological solutions for the production of blocks from soil cement. It is proposed to make soil cement blocks from portland cement brand 400 in the amount of 20 % of the mass of soil and water. Experimental addition of fly ash to the solution in different amounts depending on the cement content. It is proposed to add ash removed from the Darnytsya thermal power plant, which was sifted through a 4 mm sieve, because the ash contains a significant amount of impurities. The content of inclusions from 1 to 4 mm was up to 40 %. It is proposed to make blocks from soil cement with the addition of fly ash with the aim of improving the thermotechnical properties. It is proposed to make soil-cement blocks with two voids. To ensure high-quality compaction of products in forms, the moisture content of the content for most soils should be within 14–23 %. The maximum force that the sample can withstand was taken as a destructive load. It was decided that the use of fly ash as part of the mixture in the production of soil cement gives a positive effect. With an increase in the period of exposure of samples in water to 90 days, the average compressive strength of soil cement samples without additives and with the addition of the appropriate percentage of fly ash increases.

Abstract: The issues of ecology and economics of the use of solid organic fuels for the production of thermal and electric energy, as well as the disposal of their combustion products, are becoming more and more relevant not only in our country, but also in world practice. The formation of industrial waste, in particular ash and slag waste, creates a number of difficulties. One of the main ones is a violation of the environment, which is also relevant for the Arctic zone of the Russian Federation. On the territory of the Arctic zone of the Russian Federation, along with hydroelectric power plants, nuclear power plants and thermal power plants operating on gaseous and liquid fuels (fuel oil), a significant share (on average, at least 20%) is taken by coal generation. An equally urgent problem of the Arctic zone of the Russian Federation is the problem of road construction in permafrost conditions and extreme climatic conditions.

Abstract: Hot corrosion is the main reason of failure of boiler tubes used at high temperature in thermal power plants. This paper is an attempt to investigate the effect of different composite coatings on boiler tube steel in corrosive environment of Na₂SO₄ – 60%V₂O₅ at 900°C for 50 cycles. The coatings have been deposited with high velocity oxy fuel process. The samples were exposed to hot corrosion in a Silicon tube furnace at 900°C for 50 cycles. The kinetics of corrosion behaviour were analysed by the weight gain measurements after each cycle. Corrosion products were analysed with weight change statistics, X-ray diffraction, and scanning electron microscopy. It is found that 100Cr₃C₂ composite coatings provided the higher resistance to corrosion as compared to other types of coatings. Cr carbide layer was formed on the surface and these layers provided the protection from hot corrosion.

Abstract: Steel grade 11 is widely used to fabricate superheater pipe in the thermal power plant. Since the steam has a high temperature (above 300oC) and pressure (max. 20 MPa), lifetime of the tube/pipe decreases or the failure occurs during the operation. Problems of the steel include micro-crack, creep degradation, pit corrosion, mechanical failure, etc.; and increasing working time raises the failure potential and decreases the economy if the thermal plant has to stop operating. This research investigated the change in the mechanical properties of steel grade 11 (ASTM A335) loaded constantly at room temperature. The steel specimens were cut from a new pipe P11, hanged under various stresses (6.45 – 9.68 – 12.9 MPa) for 2160 and 4320 hours. After the loads were removed, the steel specimens were tensile tested and observed by optical microscopy and SEM. The results shown that strengths of the steel increased with increased the stress for 2160 hours, but slightly decreased for 4320 hours. There was no significant change of the microstructure including 87 vol.% ferrite and 13 vol.% pearlite, and the grain sizes were estimated as about 18 μm for all conditions. It was considered that a deformation hardening occurred in the beginning stage of loading, but the creep degradation started as the loading time was lengthened. The fact that a significant change in the microstructure was not observed in the present steels revealed that high temperature played an important role in degradation of the practical steels.

Abstract: Dissimilar metal welding (DMW) is frequently used to join stainless steels to other metals in Thermal Power Plants (TPP) and industries. DMW process has been shown to have great advantages for many years. This approach is most often used where a transition in mechanical properties and/or performance in service are required. The objective of this research is to review the basic principles of fusion welding of dissimilar metals.In experiments, the two seamless pipes with 18 mm thick, one modified SS 304L austenitic stainless steel was welded to another modified carbon steel A 106B by means of shielded metal arc (SMAW) and gas tungsten arc (GTAW) welding processes using ER309L and E 309L-16 type of filler metal. Before welding, essential variables were analysed so that creating preliminary welding procedure specifications (pWPS). After welding, weldment was tested by NDT such as visual, penetrant and radiography. Microstructural examinations were carried out including macro and micrographs, grain size analysis, and hardness measurements. Transverse tensile, and face/ root bend testing were carried out. Finally, WPS was established conformance to standards of TPP structure toward to building Nuclear Power Plant in Vietnam.

Abstract: In order to compare the corrosion resistance of conventional low carbon steel, Cu containing low carbon steel for sulfuric acid dew-point corrosion inhibition, and stainless 409L, immersion tests were carried out in 50 wt.% sulfuric acid. The effects of HCl concentraion on the corrosion behavior in a fixed sulfuric acid concentration (16.9 vol.%) was also investigated by immersion test. In addition to immersion test, field test in a thermal plant was carried out for 10 months. As a result, it was confirmed that Cu-containing dew-point corrosion resistent steel has the highest corrosion resistance compared with other materials. To verify superior corrosion resistence of dew-point corrosion resistant steel, surface morpology after various test was observed by SEM. It was found that surface corroded product of the dew-point corrosion resistant steel was much denser and thicker compared with the other steel.

Abstract: This paper presents the use of buckling-restrained braces (BRBs) in the design of the main building of a thermal power plant as an alternative for the construction of such kind of large industrial facilities. The project is located in Suqian, Jiangsu Province, a region of high seismic demand (Intensity 8) in China. The main lateral force resisting system used for the structure of this project is composed of a combination of conventional concentrically braced frames (CBFs) and buckling-restrained braced frames (BRBFs). The paper explores the seismic design and performance assessment of this industrial steel building according to the provisions of the Chinese code. Response spectrum analysis and time-history analysis were conducted under two levels of seismic hazard: minor earthquake (63.2%/50 years) and major earthquake (2%/50 years). Results indicate that BRBs effectively helped to control lateral deformation and dissipated energy in stable manner, making the structure composed of CBFs and BRBFs to show the seismic performance as intended by the code.

Abstract: The advantages and drawbacks of a modern thermal insulating material – cellular glass (foam glass) – and the use of manmade waste (in particular, thermal power plant ash-slag waste) in its synthesis were described. The results of studies into the development of composites and temperature-time synthesis modes of effective energy-saving cellular glass and materials based on it were shown, including the experimental samples of insulating boards and blocks with density of not more than 500 kg/m³; experimental samples of porous granules for lightweight concrete and thermal insulating fillers with density of not more than 250 kg/m³ –. Technology of cellular glass using the Novocherkassk State District Power Plant ash-slag waste was described. The developed technological solutions allow setting physical and mechanical properties of materials based on cellular glass (density, porosity, thermal conductivity, compressive and bending strength) by varying the amount of ash-slag waste in its composition.

Abstract: In order to solve the problem of serious dust and difficult to control in coal conveyer belt without tissue in a thermal power plant of Shanxi, this paper introduces the principle of dry fog dust suppression technology, apparatus components, advantages and disadvantages and the application in a thermal power plant. Determination of dust concentration when the dry fog dust suppression work or does not work. Data show that the rate of dry fog dust suppression is generally greater than 80%, the dust concentration is less than 10 mg/m³, especially the suppression effect on small particles of less than 10 μm dust is obvious. Practice shows that dust has been effectively suppressed and it has a good application prospect, when this technology and device are applied.