Study heat exchange in porous structures

This paper shows the problem with heat exchange depending on units of thermal power plant equipment. The type of structures is determined and the heat flow for different pressures is proposed. Studies are developed for the condition of the heat exchange surface. Devices with porous coatings eliminate the development of cracks in the components and units of TPP equipment have been suggested. The research is applicable to gas turbine units of TPP. Comparable capillary-porous and flow systems have high reliability, but the former allowed the reduction of coolant consumption dozens up to 80 times. The results show that at higher heat loads it is suitable to use in porous surfaces to control the cooling surface. Evaluation of capillary-porous structures has shown their advantages over traditional cooling systems.

A Study on PF–IFF-Based Diagnosis Model of Plant Equipment Failure

There are two types of maintenance policies for equipment: breakdown maintenance and preventive maintenance. In the case of applying preventive maintenance, the maintenance is carried out based on time or the condition of the equipment. However, with the development of Information and Communications Technologies (ICT) and the Internet of Things (IoT) technology, the data collected from equipment has rapidly increased and the use of Condition-Based Maintenance (CBM) to perform appropriate maintenance based on the condition of the equipment is increasing. In this study, based on gathered sensor data, we introduce an approach to diagnosing the condition of the equipment by extracting specific data features related to the types of failures that occur with equipment. To this end, we used the K-means clustering method, support vector machine (SVM) classifier, and Pattern Frequency–Inverse Failure mode Frequency (PF–IFF) method with the Term Frequency–Inverse Document Frequency (TF–IDF) method. As a case study, we applied the proposed approach to a centrifugal pump and carried out computational experiments for assessing the performance and validity of the proposed approach.

Vertical Seismic Isolation Device for Three-Dimensional Seismic Isolation of Nuclear Power Plant Equipment—Case Study

The purpose of this study was to develop a vertical seismic isolation device essential for the three-dimensional seismic isolation design of nuclear power plant equipment. The vertical seismic isolation device in this study has a concept that can be integrally combined with a conventional laminated rubber bearing, a horizontal seismic isolator with a design vertical load of 10 kN. To develop the vertical seismic isolation device, the vertical spring and the seismic energy dissipation device capable of limiting the vertical displacement of the spring were designed and their performances were verified through actual tests. In this study, the target elevation of the floor is 136 ft, where safety-related nuclear equipment, such as cabinet and remote shutdown console, etc., is installed. The sensitivity studies were carried out to investigate the optimal design vertical isolation frequencies for the target building elevation. Based on the results of the sensitivity study, a disc spring and a helical coil spring were selected for the vertical stiffness design, and the steel damper was selected for the seismic energy dissipation, and their performance characteristics were tested to confirm the design performance. For the steel damper, three types were designed and their energy dissipation characteristics by hysteretic behavior were confirmed by the inelastic finite element analyses and the tests in static fully reversed cyclic conditions. Through the study of the vertical seismic isolation device, it was found that 2.5 Hz~3.0 Hz is appropriate for the optimal design vertical isolation. With results of the vertical seismic isolation performance analysis, the appropriate number of steel dampers are proposed to limit the vertical seismic displacement of the spring within the static displacement range by the design vertical load.

Effects of calcination variables on quicklime yield of Nkalagu limestone

Calcination of Nkalagu limestone for the production of agricultural quicklime is presented. It entails improving the quality of limestone through calcination process. Appropriate scientific instruments/techniques (x-ray diffractometer and scanning electron microscopy) were used for the characterization of the uncalcined and calcined limestone samples. Effects of calcination variables on the quicklime yield were examined. Central composite design of design expert software was used to optimize the calcination process. Analyses of the results revealed that calcite was the major limestone’s mineralogical composition. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. The optimum yield of 74.00% was obtained at optima operating conditions; temperature of 937.41 0C, particle size of 85.99µm and time of 3.7 hrs. Characteristics of the quicklime showed that the calcination improved the quality of the sample in terms of mineralogical properties. It is recommended that the generated model should be used to develop chemical plant/equipment for limestone calcination process.

New Method of Materials Flow Calculation for Double-String SLCI Type Cement Plant (Part 1: The Whole Clinker Plant)

Materials flow values are instrumental in many industries for controlling and simulating processes, designing new equipment as well as modifying existing plants. They are sometimes impossible to determine by direct measurement in an operating plant due to the very high temperatures. This study attempted to overcome the difficulties associated with this measurement by proposing a new method to calculate materials flow of a double-string suspension preheater type of cement plant with separate line and in-line calciners (SLC-I), with heat balance error less than 1%. This study was divided into two sequential parts, with the first part presented in this paper. The methodology of the first part was to solve the conservation law of the main clinker plant equipment, supported by Bogue’s equation, the heat of calcination, and the thermodynamic properties of the related materials. The least-square method was employed for solving the overdetermined system equations obtained in the second part. The results of the first part were: the ratio of heat formation to specific heat consumption was 52.13% (> 50%), and the gas exhausted from the plant yielded more than 117 MW heat equivalent, which can potentially be recovered for electricity production.

Benthic and periphytic invertebrate contour groups in techno-ecosystems of power plants of Ukraine

Based on many years of research experience of water techno-ecosystems of thermal and nuclear power plants a brief review of the main patterns of formation of the composition, cenotic structure, elements of the functional organization of benthos and periphyton communities was made. It was shown that the composition of zoobenthos and zooperiphyton in some cooling ponds, other technical water bodies and watercourses was quite rich. In addition, due to the rather intensive invasive process, the list of taxa is constantly expanding. Species of tropical and subtropical origin have been recorded. Of particular importance is the invasion of species that may be the cause of bio-hindrances in the operation of power plant equipment. Techno-ecosystems have been studied to varying degrees. One of the most studied for a long time are the cooling ponds of Khmelnitsky and Chernobyl nuclear power plants. Hydrobiological research and monitoring at the first one has been carried out for more than 20 years. It was found that the influence of biotic invasion (invasion of Dreissenidae) may have a significant impact, comparable to extreme technogenic factors, on both the ecosystem and technical water supply facilities. The stages of contourisation and decontourisation processes in the Khmelnitsky NPP techno-ecosystem were established. At the Chernobyl NPP cooling pond, studies were carried out during all periods of the existence of the reservoir and the power plant, until the process of uncontrolled pond descent and transforming it into a unique wetland. Based on the obtained data, practical recommendations relating to the organization of hydrobiological and environmental monitoring, as well as reducing biological hindrances and improving the reliability of power plant equipment have been developed.

Simulation for Predicting Condition of Plant Equipment

Condition-based maintenance (CBM) is a maintenance program that recommends maintenance decisions based on maintenance information by condition monitoring. To apply CBM to industrial systems, it is important to diagnose condition of equipment appropriately based on the knowledge of abnormal condition of the equipment. In nuclear power plant, however, it is quite difficult to obtain the knowledge of abnormal condition. For this reason, simulation is expected to be an effective approach to estimate conditions of equipment instead of data acquisition. In this study, we focused on and built models for a motor operated valve and a pump, since the inspection cost is generally expensive due to the number of them in nuclear power plant. We considered a pump system and analyzed the measurement values in normal and abnormal conditions. Our analytical result reproduces the behavior of the measurement values and shows the characteristic deviation from normal condition in abnormal conditions.