Determination of average relative capital investment of 30–125 MW combined-cycle plants commissioned at Russian thermal power plants in 2015–2020. Comparative analysis with data obtained in 2010–2014

The present work examines average relative capital investment and fuel consumption for electric and thermal energy supply of the combined-cycle plants having 30–125 MW gas turbines commissioned at Russian thermal power plants in 2015–2020. In this work, we used general calculation methods of average relative capital investments and fuel consumption for the electrical and thermal energy supply using power equipment of thermal power plants. To assess the scope of commissioning gas turbines incorporated into the combined-cycle plants, they were classified into three groups by electrical power: 30–59 MW, 60–99 MW and 100–125 MW. The scope of commissioning gas turbines incorporated into the Russian combined-cycle plants in 2015–2020 was analysed. The average relative capital invest-ment in combined-cycle plants having 30–125 MW gas turbines, as well as the average specific fuel consumption for the electrical and thermal energy supply, were calculated. The calculations were carried out for each part of combined-cycle plants integrated into thermal power plants with a breakdown by seven Unified Energy Systems of Russia. The quantita-tive commissioning of gas turbines is compared for the periods from 2010 to the economic crisis of 2014 and after 2014 to the present: a ~2.5-fold decrease is demonstrated. A preliminary evaluation of the increase in average relative capital investment in combined-cycle plants having gas turbines of the same electric power was performed.

Influence of Acid-Activated Micro-Dispersed Additive on the Properties of Cement Sulphate-Resistant Compositions

Research is devoted to the possibility of obtaining a composition based on a microdispersed ash additive and a plasticizer. Waste from sewage sludge ash used. They are formed at thermal power plants. Such ashes are distinguished by the presence of a large amount of organic matter and a low calcium content. Therefore, they are rarely used in construction. The activation of the waste fuel and the use of a plasticizer can improve the performance of cement compositions with the inclusion of sewage sludge ash.

Application TAPM-AERMOD system model to study impacts of thermal power plants in SouthEast and SouthWest areas to the air quality of HCMC: current status and according to Vietnam power planning VII toward 2030

Vietnam’s urban areas have faced serious environmental pollution issues, including water pollution, municipal waste, and air pollution. Vietnam’s real gross domestic product (GDP) has been experiencing positive growth for the past five years since 2016. And in 2019, Vietnam’s real GDP increased by 7.02% compared to the previous year. To maintain the growth rate, there is a huge amount of electricity required, not accounting for the other sectors. Thermal power plants generate more than 50% of total electricity in Vietnam, therefore, it is said that coal-fired power plants have been the major sources of air emissions and caused a serious impact on the environment. Recently air pollution is a hot issue in Ho Chi Minh City (HCMC), the air quality is being polluted by PM2.5, O3, CO, NO2, and TSP. Despite that, the neighboring areas of the city will install more coal-fired power plants, threatening to degrade the quality of the environment. Therefore, the objectives of this study are (i) Modeling the impacts of thermal power plants in SouthEast and SouthWest areas on the air quality of HCMC for two scenarios (current status in 2019 and future according to Power planning VII (adjusted) toward 2030); And (ii) Develop interprovincial air quality protection solutions. The research applied the TAPM model for meteorological modeling and AERMOD model for air pollution dispersion. The annual average PM2.5 concentration in the study area was approximately 0.121 μg/m3 and the highest concentration at a location close to Vinh Tan thermal power center with 8.61 μg/m3. NO2 the annual average concentration from power plants in 2020 and 2030 blows to HCMC and contributes to HCMC’ air quality only 0.01 and 0.03 μg/m3, respectively. The 24 hours average concentration of SO2 from power plants in 2030 blows to HCMC and contributes to HCMC’ air quality of 10 μg/m3. The 24 hours average SO2 levels of HCMC in 2030 is 39.2 μg/m3, higher than WHO’s guideline (20 μg/m3). Currently, air pollution in HCMC is polluted by PM2.5, SO2, and NO2 and cause bad effect to public health. However, in the future with the contribution of 33 thermal power plants under intercity/provinces air pollution dispersion, air pollution HCMC will be worse and affect public health. Air pollution HCMC will be a huge impact on HCMC’s public health in the future due to the contribution of 33 thermal power plants under intercity/provinces air pollution dispersion. The paper developed 7 main mitigation measures to reduce the impacts of air pollution from the power plan and reduce the impacts of air pollution on HCM’s public health. The measures are focused on using clean fuel, advanced technology, and controlling trans-provincial air pollution.

Structural-&-Phase Condition and the Damageability of the Welded Joints of Steam Pipelines at Thermal Power Plants

The authors studied the interrelation between the type of structure and the damage rate of the welded joints of steam pipelines made of the heat-resistant pearlitic steels that were operated for a long time, i.e. more than 270 thousand hours in the conditions of creepage and low-cycle fatigue. The purpose of this research was to establish the interrelation between the structural-&-phase condition of the metal used for welded joints of the elements of steam systems and their damageability rate for the service life of welded joints exceeding 270 thousand hours. During the studies, the methods of optical and electron microscopy were used according to the requirements of the guideline documentation and also the methods that are used for the determination of mechanical properties. The level of their reliability has been substantiated and the residual life has been determined. To impart functional performances to welded joints we used well-known methods that were appropriately emended according to the structural changes of above joints. Such changes condition the conversion of the original structure of welded joints into the ferrite-carbide mixture. The availability of the conversion process of the initial structure on the thermal action zone sections (TAZ) of welded joints has essential distinctions due to a different disposition of metal to its own damageability. On the whole, the welded joints are damaged more intensively in comparison to the basic metal of steam pipelines. The analysis of the structural state of welded joints in the steam pipelines of thermal power plants as for the extension of their service life results in a considerable economic effect. Understanding the fact that the metal deterioration in welded joints adheres mainly to the fragile mechanism we managed to establish the level of their damageability that demands the renewal of damaged welded joints. We believe that the damageability level of welded joints that tots up to 0.25 or 0.35 of the volume of their TAZ section should be considered as critical for the service life exceeding 270 thousand hours. The damaged welded joints should be renewed throughout the time period of 15 to 20 thousand hours as soon as the specified damageability level is attained.