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The natural gas tightly correlates with our everyday life. However, driven by gray incomes, some users are prone to stealing gas by refitting the equipment without permission. Especially for the boiler room users in winter, this phenomenon appears more rampant. Traditional gas-theft detection methods highly rely on the on-site inspection, where exists ineffective and randomness. In this paper, we propose a data-driven approach, named SVOC, to detect gas-theft suspects among boiler room users. Our approach consists of a scenario-based data quality detection algorithm, a deformation-based normality detection algorithm, and an One-Class Support Vector Machine (OCSVM) based anomaly detection algorithm. Specifically, considering the temporal proximity between the gas consumption and the outdoor temperature, the normality detection algorithm adopts a similarity-based deformation correlation to detect normal boiler room users out of abnormal ones. Then, we employ OCSVM as the anomaly detection algorithm to capture various features across multiple data sources, aiming to distinguish gas-theft suspects from the remaining irregular users. Here, the detected normal and abnormal users are fed into the OCSVM for training and prediction, respectively, which can overcome the label scarcity problem. We conduct extensive experiments on a real-world dataset during one heating season. The results demonstrate distinct advantages of our approach over various baselines.

With the worldwide rapidly increasing urbanization, the demand for heating increases too. To meet the substantially higher heating-demand, traditionally, the number of gas-fired boilers is simply increased. Unfortunately, this also causes severe air pollution. A viable alternative is solar heating systems that could be added to the existing gas-fired boilers system. This study investigates a heating system, which combines solar heating and existing gas-fired boiler heating into one system. The optimal individual capacity of the system is determined and the operation characteristics, energy saving, and economics are analyzed. The results showed that the combined heating system has a clear advantage with respect to both energy saving and economics over the traditional solution (gas-fired boiler-capacity expansion). For an expansion rate of 20%, for example, the average energy-saving rate is as high as 69%. With increasing capacity, the difference per unit heating-area cost between the two systems increases. This means that the combined heating system is even more beneficial when the capacity increase is high. This study shows a new way to meet increased heating demand effectively, which is especially useful for cities that require a significantly-increased heating capacity.

This work presents a computational investigation of hydrodynamics, coal combustion and NOx emissions in a tangentially fired pulverized coal boiler at different loads (630, 440 and 300 MW; relative loads of 100%, 70% and 48%) to clarify the effect of load change on the furnace processes. A computational fluids dynamics model was established; the flow field, temperature profile, species concentration and NOx emissions were predicted numerically; and the influence of burner tilt angles was evaluated. Simulation results indicate that a decrease in boiler load decreases the gas velocity, attenuates the airflow rotations, and increases the tangent circle size. The high-temperature zone and flame moved toward the side walls. Such behaviors impair air–fuel mixing, heat transfer and steady combustion in the furnace. In terms of species concentrations, a decrease in boiler load increased the O2 content, decreased the CO content, and decreased the char burnout rates only slightly. A change in boiler load from 630 to 440 and 300 MW increased the NOx emissions from 202 to 234 and 247 mg/m3, respectively. Burner tilt angles are important in coal combustion and NOx emissions. A burner angle of –15° favors heat transfer and low NOx emissions (

Boilers are one of the most used units for both heat generation plants and industry systems. Their operation is subjected to different working loads and maintenance requirements. Exploitation experience points out critical boiler zones where failures and break downs typically occur. This paper analyzes critical zones in hot water fire-tube boiler. Experimental procedure was performed on the model of this type of boilers and its critical element. The tube plate of hot water boiler was identified as the most critical one. Experimental analysis and numerical model verification were performed using Aramis system based on 3D Digital Image Correlation method. Numerical analysis was done in Ansys Software Package and verification of results was done based on measurements obtained by strain gauges and local measurements performed by the Aramis system. Stress-strain analysis indicates the critical zones of boiler tube plate. The character of change parameters such as strain and stress occurring in the critical zones can be verified both by experimental and numerical data. The paper presents a novel approach in experimental and numerical analyses that can be conducted in similar units and used for existing unit optimization, as well as for new product testing on different loads and provide opportunity for further development and improvement for practical industrial application.

The paper presents the mathematical model of the heat transfer processes for a single screw ash cooler (SSAC) working with a circulating fluidized bed (CFB) boiler. The validation of the model is based on experimental measurements made on a 230 MWe power unit. The analysis of measurement data from two bottom ash coolers showed that the correct prediction of the outlet temperatures of ash and cooling water requires the determination of their individual ash filling characteristics (i.e. coolers). The numerical results confirm that the mixing model proposed by Schlunder correctly predicts the heat transfer coefficient for ash. The described mathematical model can monitor the operating conditions of the single screw ash cooler. It enables the determination of the optimal volumetric flow rates of the cooling water in order to get its highest possible outlet temperature, and then for this water to be used, e.g. for sanitary purposes.

In current trends the wood pellets are very significance role in the replacing of boiler fuel; it is a surrogate and renewable fuel. For this study comparative analysis of the fuel performance in the boiler is carried out effectively. Two categorize of fuel like as raw wood pellets and wood pellets are immersed in the bio- ethanol are taken to this experimental work. The thermal characteristics and thermal efficiency of the boiler with influence of two types of fuels are conducted efficiently. Normally the wood pellets having small pores it is used to absorb the bio ethanol while in immersion. Amid in the two fuels, wood pellets immersed in the bio ethanol are provided and increase the thermal properties as well as thermal efficiency compared to raw pellets. The flue gas constituent’s percentage such as carbon monoxide, oxygen, carbon monoxide and nitrogen oxides are analyzed, additionally the high temperature of flue gas also measured in the outlet of the chimney. No alteration is made in the boiler setup which is comfortable to both fuels.

This study deals with an economic and environmental Life Cycle Assessment of an innovative thermal energy storage - based on phase change materials embedded in open-cell copper foams - coupled with a solar heating and cooling residential system located in Italy. The results are compared with a traditional water-based storage with the same energy storing capacity. For both systems, an auxiliary gas-fired boiler is considered to integrate the renewable energy, in order to satisfy the building heating and cooling needs. Compared to the traditional system, the innovative storage guaranteed a lower natural gas consumption, 428 m3/y respect to 525 m3/y, due to better energy utilization obtained with a constant heat release/accumulation temperature during the solidification/melting phase of the paraffin. This reduction compensates the greater impact due to the consumption of raw materials and energy during the assembly phase of the innovative storage, and determine an abatement of the environmental impact over the 20 years of operation of about 14.6%, i.e. 1517 pt against 1777 pt in terms of global impact indicator. On the other hand, the innovative system proposed appears to be still expensive if compared to the conventional water-based storage, with an estimated annual cost of € 1,240 against € 696.

As a result, in Libya, where temperatures do not drop significantly during the winter months, induction boilers connected to solar panels provide a practical and cost-effective solution for home heating. Because solar energy is utilized to its maximum capacity, the required room temperature can be easily achieved with a boiler with a low resistance capacity. Resistance boilers, on the other hand, have lost their appeal because of frequent failures and the need for considerable effort during the transformation process. Fortunately, the boiler's failure potential is minimal at this point; therefore, water heating using the induction heating principle is a suitable option in this situation. In this research, the goal is to look at water heating technologies as a potential replacement for electric boiler applications. Because of this, a specific method for heating buildings and water heating was developed and put forth for consideration. The electrical connection of the solar panels served as the power source for the planned system and satisfactory results were obtained. The results were verified using theoretical calculation and Computational fluid dynamics (CFD) software. The performance of the heat exchanger was evaluated, and the results showed that the efficiency is improved by decreasing the flow rate, tube diameter, coil diameter, and coil length; moreover, the performance index is enhanced by increasing the tube diameter and decreasing the coil, vessel diameter.

For the wide industrial applications of supercritical CO2 (S-CO2) circulating fluidized bed (CFB) technology, the simulation on scale-up characteristics would be a crucial and reliable means to investigate specific combustion process before establishing costly and complex boilers in industry. This study conducted 3D CFD simulations in lab-scale, pilot-scale, and industry-scale S-CO2 CFB boilers (0.1 MW to 600 MW) based on the Eulerian-Lagrangian method. The scale-up characteristics were comprehensively discussed from the angles of furnace structure, gas-solid flow dynamic, combustion characteristics, heat transfer characteristics, gas emission characteristics, and boiler efficiency with the fitting formulas of the scaled-up regularities derived. Results show that with the power capacity increased, the heating surface area in the furnace and flue system enlarged, in which the furnace heating surface accounted for a larger proportion. The particle flow rates and the circulating ratio increased, and the voidage distribution was less affected by disturbance with more complicated core-annulus structures appeared. With the thermal input increased, furnace temperature decreased accompanied by better thermal inertia, and the heat transfer of cold walls enhanced although its transverse distribution became uneven. The emissions of CO, NOx, and SO2 from the industry-scale CFB were lower than the other two scales. The carbon conversion ratio and the combustion efficiency increased with the thermal input increased, and the growth slowed for industry-scale boiler.

This work reviewed the historical literature associated with the Dragon experiment and Water Boiler reactors operated at Los Alamos during the Manhattan Project. Frisch's invited talk given at the Fast Burst Reactor Conference held the University of New Mexico in Albuquerque, NM in 1969 is quoted. From the literature review, basic models for the Dragon experiment and for a Water Boiler type assembly (aqueous homogeneous reactor) were created that can be used for conducting multi-physics simulations for criticality excursion studies. This methodology utilizes the coupled neutronic-hydrodynamic method to perform a time-dependent dynamic simulation of a criticality excursion. MCNP was utilized to calculate important nuclear kinetic parameters that were incorporated into the models. Simulation results compared reasonably well with historic data.

This study proposes a method for the evaluation of the efficiency of a heat supply system based on a correlation analysis of the data of the system's operations. The data from the system's operations have been analysed and a correlation equation has been applied to obtain the results of the analysis, which are then used for further calculations. The data can be divided into two groups: data characterising the condenser operations in the boiler house, and data characterising heating networks.

For an air staged combustion boiler, the rational organization of jets to form closing-to-wall film using as little air as possible plays a key role in resolving the high temperature corrosion problems. In this work, a comprehensive computational fluid dynamics (CFD) model including hydrodynamics and coal combustion is established for a 660 MW opposed wall fired boiler. Based on the grid independence and model validation, the flow field, temperature profile, and species concentration are predicted, and the influences of the structure of nozzles and the operation parameter of jets are further evaluated. The results show that the corrosion area of the side wall is dependent on the jet projection velocity and nozzle structures. The increase of the jet velocity does not always have an active influence on the reduction of corrosive area. Only increasing the nozzle diameter does not always have a positive impact on the improvement of the corrosion. The increase of the jet inclination angle can extend the jet trajectory, contributing to increase the oxygen coverage area. Reasonably adjusting the jet inclination angle of each layer can obtain the lower corrosion area. The increase of jet row number leads to a decrease in the spacing between rows, which enables the downstream jet to penetrate deeper into the cross stream. By increasing the number of jet layers and reducing the jet velocity of each layer, the lowest corrosion area can be obtained.

In order to improve the performance properties, in particular viscosity-temperature, of boiler fuel, it is proposed to combine them with narrow fuel fractions obtained by thermal destruction of secondary polymer raw materials (low pressure polyethylene and polypropylene). When compounding grade 100 fuel oil with narrow fuel fractions, the values ​​of density are reduced to 865 (873) kg / m3, conditional viscosity to 2.50 (2.63) deg. um., pour point up to 8 (13) °C), sulfur content up to 0.17 wt%. and the lower heat of combustion increases to 43606 (43850) kJ / kg. At the same time, there is a gradual decrease in the value of the flash point to 114 (127) °C. This reduction is a negative point, which leads to increased fire safety of fuel oil during its use, storage, pumping and transport. However, the values of the flash point, according to the requirements of regulatory documentation, are within acceptable limits. That is, the value of this indicator can limit the content of fuel oil in narrow fuel fractions. It is determined that the rational concentration of narrow fuel fractions in the composition of fuel oil grade 100, is within 30% of the mass. Within these limits, there is a permissible decrease in flash point values – an indicator that characterizes the fire hazard of fuel oil during its use, storage, pumping and transportation against the background of improving other performance properties of fuel oil. The production of the proposed compound boiler fuel on the one hand allows to expand the raw material base of the process by involving in the production process secondary polymer raw materials – solid waste subject to mandatory disposal, on the other – to meet existing demand for boiler fuel by increasing its production., З метою поліпшення експлуатаційних властивостей, зокрема в’язкісно-температурних, котельного палива запропоновано їх компаундування з вузькими паливними фракціями, отриманими шляхом термічної деструкції вторинної полімерної сировини (поліетилену низького тиску та поліпропілену). При компаундуванні мазуту марки 100 з вузькими паливними фракціями, відбувається зниження значень густини до 865 (873) кг/м3, умовної в’язкості до 2,50 (2,63) град. ум., температури застигання до 8 (13) °С) , вмісту сірки до 0,17 % мас. та підвищується нижча теплота згоряння до 43606 (43850) кДж/кг. При цьому, відбувається поступове зниження величини показника температури спалаху до 114(127) °С. Таке зниження є негативним моментом, який призводить до підвищення пожежонебезпеки мазуту при його використанні, зберіганні, перекачування і транспортуванні. Але, при цьому, значення показника температури спалаху, згідно вимог нормативної документації, знаходяться у допустимих межах. Тобто, значенням саме цього показника можна обмежувати вміст у мазуті вузьких паливних фракцій. Визначено, що раціональна концентрація вузьких паливних фракцій у складі топкового мазуту марки 100, знаходиться у межах до 30% мас. У цих межах спостерігається припустиме зниження значень температури спалаху – показника, що характеризує пожежонебезпеку мазуту при його використанні, зберіганні, перекачування і транспортуванні на фоні поліпшення інших експлуатаційних властивостей мазуту. Виробництво запропонованого компаундованого котельного палива з одного боку дозволяє розширити сировинну базу процесу, шляхом залучення до виробничого процесу вторинну полімерну сировини – тверді побутові відходи, що підлягають обов’язковій утилізації, з іншого – задовольнити існуючий попит на котельне паливо, за рахунок підвищення обсягів його виробництва.

This paper investigated the use of fatty acid distillate (FAD) produced as a by-product of edible oil refining as a fuel source for boilers. Using a diesel heater to model the combustion chamber of a fire tube boiler showed that diesel blends with FAD up to 60% could be used with different levels of preheating. A small to medium sized edible oil refinery was used to generate an economic model. It was estimated that an edible oil refinery of this size required a boiler able to supply 3 GJ/h of energy. In this situation, the FAD produced could provide approximately 57% of the yearly energy requirements for the boiler. An economic analysis revealed that using FAD (42 MJ/kg) as fuel will increase its value from New Zealand Dollar ($) 0.425/kg to approximately $1.30–1.55/kg depending on the cost of standard boiler fuel. Running the boiler on LPG ($30/GJ) or diesel ($37.7/GJ) was estimated to cost $960,000 and $1,200,000 respectively per year. If all the FAD was used as alternative fuel to provide 57% of the yearly energy, then up to $700,000 could be saved each year.

Background A large share of the building energy usage corresponds to heat loss compensation and heat gain rejection. High energy consumption to provide sanitary hot water should also be considered. Methods In this paper, by introducing two scenarios, energy usage in both sections is examined in four regions (warm climates). In the first scenario, adding PCM to the vertical walls along with the ceiling, the variations of heat loss/heat gain parameters were evaluated. In the second scenario, using a solar system filled with nanofluid, the reduction in boiler energy usage was investigated. Findings The usefulness of the first scenario depended on the PCM melting temperature. PCM 24 performed better in warm climates. In the first scenario, the energy-saving was in the range of 620–6600 kWh year for warm climate. Although the first scenario was not always useful, the second scenario always reduced the boiler energy usage. The use of collectors filled with Al2O3/water led to energy-saving within the range of 3400–4500 kWh year .

High-temperature corrosion has been a critical issue for coal-fired boiler steels, particularly Cr-containing steels SA213-T22, for many decades. Hot combustion gases containing CO2, CO, N2, and un...

This study applies environmental life cycle assessment to quantify and compare the environmental profile of the production and use of wood pellets for residential heating (baseline) and compares the pellet system with two different alternative systems for residential heating in Mexico: (1) the use of LPG heater and (2) one electricity heater powered by three different sources of electricity. The baseline system boundaries include the stages of forest management, transportation, industrial, distribution, wood pellet energy conversion, and ash management. First-hand data and measurements of the emission profiles in the field and laboratory were developed. The functional unit was 1 MJ of thermal energy for residential heating. Environmental impacts were calculated for six impact categories from the ReCiPe midpoint method. Furthermore, a sensitivity analysis was performed to evaluate the influence of the allocation criteria (mass and economic) as well as adopting different values for the electricity sources (system’s hotspots). The results obtained for each impact category show a relatively wide range of variation when the five scenarios of the heating systems are compared and analyzed. Electricity heater powered with photovoltaic electricity is better for all the impact categories analyzed. The performance of pellets and LPG is very close, but the pellets have lower impacts on global warming (three times), fossil resource scarcity (four times), and acidification. Therefore, the use of pellets in an efficient boiler is a promising option for residential heating.

Passenger rolling stock is an important component of passenger transportation services, which should ensure not only traffic safety, but also comfortable transportation conditions. Studies on the energy saving of railway rolling stock have revealed shortcomings in the operating documentation that increase the unproductive consumption of thermal energy by passenger cars during the operation of a heating system with a combined electric-coal boiler in electric heating mode. Experimental measurements confirmed the presence of unproductive losses of thermal energy through the intake blinds of the ventilation system due to the infiltration of outside air during downtime at the points of formation and turnover of passenger cars. Also, experimental measurements showed that there is a leak of warm air through the deflectors to remove exhaust air from the car into the environment. This is their regular mode of operation, but as highlighted in the author's early publications there are two zones of temperature fields in the body of the passenger car with different temperature regimes, which are separated by a decorative ceiling. The results show that the leakage of warm air through the deflectors occurs from the temperature field zone with a higher temperature, which increases the unproductive consumption of thermal energy. Thus, by making appropriate changes to the operating documentation based on the study, the energy efficiency of passenger rolling stock will be greatly improved in its further operation. In particular, it is established that the proposed modernization in order to increase the energy efficiency of the heating system can be carried out at relatively low cost, in modern car repair depots during overhauls, and also needs to be considered when designing new passenger cars.

During operation in boiler units of modern condensing boilers or modernization of old-style boilers, water condensate is formed due to heat-recovery equipment in the mode of cooling exhaust-gases below the dew point of water vapor. At natural gas is burned in equipment, the range of values of the pH value of the condensate is within the range of 3 ÷ 6. In this connection, the problem arises of the useful use of this condensate or its safe drainage into the sewer network. At useful use, the resulting condensate can be used for the needs of the boiler units (for washing boilers, in chemical water-purification systems) or outside the boiler house (for laundries, greenhouses, swimming pools, etc.). In the case of condensate drainage into the city sewer network, as a rule, its preliminary decarbonization is required. This is a necessary environmental measure and operational standard to protect the sewer network and related equipment, including treatment facilities, from premature wear. Among the directions of condensate decarbonization known in Ukraine, the most common are: - decarbonization by degassing by the contact method, which consists in removing CO2 from the heated solution by blowing air in the nozzle layer (ceramic or plastic), through which condensate flows. Degassing occurs due to the instability of the H2CO3 compound, which, when heated, easily decomposes into H2O and CO2; - chemical decarbonization, by combining carbon dioxide in an insoluble compound with various reagents, which are added to the container using a dispenser; - decarbonization by passing the condensate through a granular filter containing calcium carbonate, such as marble chips or lime. Removal of carbonic acid from condensate during filtration in a layer of marble chips is seen as the simplest method of decarbonization of water condensate from those considered. On the basis of this method of decarbonization, the authors propose a technical solution for the developed neutralizer with a description of its design and operating principle. The paper presents the results of calculated studies of the volumes of formed condensate and an example of its safe use in the case of modernization of a gas-fired water-heating boiler with a nominal thermal power of 1 MW by a heat-recovery system with simple or complex use of heat. It is shown that when using modern heat-recovery technologies in gas-fired boiler houses, there are different circuit and technical solutions for possible useful use or safe evacuation of acidic condensate formed during the implementation of these technologies. In cases where it is advisable to neutralize this condensate, there are effective methods for its decarbonization and appropriate equipment.

The development over the last decade of the district heating (DH) network of Gleisdorf (Austria) represents an innovative example for a transition to a 4th generation DH network (4GDH). The local DH operator has strong ambitions towards implementing a highly efficient, nearly 100% renewable DH system using local resources. These goals will be achieved by the development and implementation of a novel control strategy, namely a “Virtual Heating Plant” (VHP) control concept. The VHP concept is an intelligent high level control system using operating data for real time calculations and a 24h prediction to optimise the overall DH network. The VHP control is fully implemented into the DH system and led to an improved and more flexible unit commitment, higher solar yields and more stable operating conditions. This paves the way to integrate multiple decentralised local heat sources and existing boiler units as well as other systemic approaches (e.g. sector coupling with waste water treatment plant, cascading heat supply out of the return pipe, stepwise system temperature reduction, implementation of an intelligent, decentral storage concept) and non-technical measures (e.g. user and stakeholder integration).

Целью исследований является анализ возможных аварийных ситуаций при разгерметизации газопровода, прилегающего к котельной и находящегося в ней, а также определение горизонтального радиуса действия ключевых поражающих факторов при аварии. В качестве примера произведен расчет аварийной ситуации для участка газопровода среднего давления. Определены значения максимального избыточного давления, импульса фазы сжатия воздушных волн давления и радиусов зон поражения при взрыве топливо-воздушной смеси. Даны рекомендации для профилактики возникновения аварийной ситуации. The purpose of the research is to analyze possible emergency situations during depressurization of the gas pipeline adjacent to the boiler room and located in it, as well as to determine the horizontal radius of action of the key damaging factors in case of an accident. As an example, an emergency situation was calculated for a section of a medium-pressure gas pipeline. The values of the maximum overpressure, the pulse of the compression phase of the air pressure waves, and the radii of the affected areas during the explosion of the fuel-air mixture are determined. Recommendations for the prevention of an emergency are given.

Рассмотрена проблема сокращения затрат при потреблении электрической энергии оборудованием центральной котельной средней мощности. Перспективным направлением в решении этой задачи является использование альтернативного источника электроэнергии в виде газопрошневой установки. Теплогенерирующие установки для централизованного теплоснабжения были рассчитаны с учетом минимального потребления электроэнергии и достижения надежности. Проведен анализ потребления электроэнергии оборудованием котельной установленной мощностью 4,7 МВт. Определены технические характеристики газопоршневой установки, выбранной в качестве нового источника электроэнергии. Проведены технико-экономические расчеты стоимости производства собственного электричества для котельной. Применение собственного источника электроэнергии позволяет снизить стоимость электроэнергии в сравнении с покупкой от центральных электросетей. Сделан вывод о том, что применение собственного альтернативного источника электроэнергии для котельной - это выгодное вложение для снижения финансовой нагрузки на теплоснабжающую организацию и для снижения стоимости тарифа на тепловую энергию. The problem of reducing cost of electricity consumption by the equipment of the central boiler house of medium capacity is considered. A promising direction in solving this problem is the use of an alternative source of electricity in the form of a gas-piston installation. Heat generating plants for district heating were designed taking into account the minimum electricity consumption and achieving reliability. We carried out the analysis of electricity consumption by the boiler house equipment with an installed capacity of 4.7 MW. The technical characteristics of the gas-piston plant selected as a new source of electricity were determined. As well we carried out technical and economic calculations of the cost of producing own electricity for the boiler house. The use of its own power source allows one to reduce the cost of electricity in comparison with the purchase from the central power grid. It is concluded that the use of its own alternative source of electricity for the boiler house is a profitable investment to reduce the financial burden on the heat supply organization and to reduce the cost of the heat energy tariff.

After running for about 59 000 h, the tubes at the intermediate mixing header of the furnace water wall leaked in an ultra-supercritical boiler. Preliminary analyses show that the primary crack may be initiated from two kinds of crack. One kind of crack is the dense transverse cracks in the external walls of the fireside, and the other one is the crack in adjacent H-shaped fin fillet weld. In order to figure out the initiation of the primary crack, the macroscopic morphology, chemical composition, microstructure, Vickers hardness and fracture morphology observation were conducted on the sample tube. The oriented dimples in the primary crack indicate that the crack propagates from the external side to the inner side. The erosive metal loss at fireside surfaces of tubes adjacent to the initial cracking shows significant differences. It is indicated that the primary crack is initiated from one side connected with the H-shape fin fillet weld crack. Based on comprehensive analyses of material quality of the sample tube and boiler operation data, it can be concluded that the wall temperature of water wall tubes changes with the frequent and large fluctuation of boiler load due to peak regulation operation, which is the root cause of fatigue cracking of H-shape fin fillet weld.

In this study, a circulation-type fluidized bed boiler's exergy performance in a power generation plant was investigated. The boiler was examined not as a whole but by dividing it into its sub-systems. In the analysis, the sub-systems' exergy performance was evaluated in terms of criteria such as exergy efficiency, exergy destruction, fuel depletion ratio, relative exergy destruction ratio, exergetic improvement potential, and productivity lack ratio. In addition, the effect of different dead state temperatures on these exergy performance criteria is compared and discussed. As a result of the analysis, the highest exergy efficiency was achieved in the furnace with 80.2% at 6℃, while the highest exergy destruction occurred in the furnace as 18,118.9 kW at 27℃. The highest exergetic improvement potential was realized in Economizer-II with 11,593.82 kW at 6℃, and the lowest in Economizer-I at 27℃ with 631,9 kW. The effect of the increase in the dead state temperature on the exergy performance criteria applied to boiler sub-systems was variable. It showed its effect as an increase in some sub-systems and a decrease in others.

Industrialization and accelerated population growth generate side effects on various social aspects, and the environmental issue is worrisome due to the impacts caused by social evolution. The management of industrial waste is a great challenge that involves both control of its generation and the proper disposal, ensuring environmental sustainability. Boiler ash residue is found in abundance in factories that use this equipment for steam generation. This abundance occurs due to the lack of a place for proper disposal or reuse of the residue. In view of this scenario, this article had as a guide question: Would it be possible to use this residue in the production of structural concrete? The aim of this study was to classify the residue by defining its possible form of use in concrete dosage and to perform experimental dosages with the use of industrial boiler ash to evaluate its possible technical contributions to basic properties of concrete. For this, samples were collected by an industry installed in the city of Uberlândia, State of Minas Gerais, active in several sectors such as agriculture, animal nutrition, pharmaceutical and others. The classification of boiler ash was performed by applying the Brazilian normative procedures and parameters used for classification of binders and aggregates for concrete. Considering its granulometric curve and density, the residue was classified as light and very thin aggregate, thus adopting the methodology of partial replacement of the thin aggregate by boiler ash. It was verified that there was a reduction in the workability of concrete in the fresh state proportionally to the residue content used. Therefore, it is necessary to use superplasticizer additives in these cases to maintain the expected workability. A reduction in the density of concrete was noticed when the residue was used, considering as necessary the attention to this property of the concrete in relation to the content used of the residue in the dosage. It was also observed when comparing the dosages with the use of the residue at the standard dosage, that there was a reduction in compressive strength. However, there was no great variation in compressive strength between the dosages with different substitution levels used. It was concluded, therefore, considering the levels used in this study, as feasible the use of this residue in the production of structural concrete.

Resumo Os problemas relacionados à combustão da biomassa e o seu impacto sobre a eficiência das caldeiras dependem das características do combustível e do projeto e operação dos equipamentos. Assim, este estudo teve como objetivo mapear os problemas associados à geração, coleta e tratamento das cinzas da biomassa florestal queimada em caldeiras industriais. O estudo foi realizado em uma usina termelétrica que gera 28MW/hora e usa biomassa florestal como combustível. Foram feitas três coletas de cavacos de madeira, antes da entrada na fornalha da caldeira e em quatro locais de passagem de cinzas na caldeira, onde ocorre o tratamento e recolhimento para disposição final deste resíduo da biomassa. Parte do mix de biomassa foi calcinado em laboratório para comparação entre os pontos de amostragem com as propriedades da biomassa. As propriedades analisadas foram: composição química elementar inorgânica; teste de fusão das cinzas e a potencialidade de ocorrência de problemas por meio dos índices de: deposição das cinzas (R); escória (Rs); incrustação (Fu); viscosidade (Sr) e álcali (Al). Os compostos presentes em maior concentração nas cinzas foram os óxidos de silício, alumínio, ferro, cálcio, potássio e magnésio. A temperatura de fusão das cinzas foi entre 1261°C e 1385°C. O mapeamento dos problemas apontou baixos riscos de formação de escória e viscosidade. O índice de incrustação foi alto para o decantador (0,69) e o readler teve médio potencial de viscosidade (1,11). A formação de álcali ocorreu no readler e decantador, provocando corrosões nestes pontos. Os cálculos dos índices de deposição foram capazes de expressar os problemas que ocorrem na queima da biomassa florestal em caldeira. Abstract The nature of the problems associated with the biomass combustion in boilers and their impact on the performance of combustion equipment depends on the fuel’s characteristics, and the design and operation of the combustion equipment. Thus, the objective of this study was to map the problems associated with the generation and treatment of forest biomass ashes in an industrial boiler. The study was developed in a thermoelectric plant with a production of 28MW / hour originated from the combustion of residual forest biomass. Three biomass samples were collected before entering the boiler’s furnace and at four flowing points inside the boiler, where the treatment and recovery for the final disposal of the biomass ashes occur. To compare the collection points in the boiler and the biomass properties, part of the samples were calcined in the laboratory. The analysed properties were: inorganic elemental chemical composition; the ashes fusion test and the potentiality of occurrence of problems through the following indices: ash deposition (R); slag (Rs); inlay (Fu); viscosity (Sr) and alkali (Al). As for the elemental chemical composition, the compounds with the highest concentrations were silicon, aluminum, iron, calcium, potassium and magnesium oxides. The melting temperature of the ashes was between 1261 ° C and 1385 ° C at the collection points. The mapping of the problems indicated low risks of formation of slag and viscosity. The fouling index was high, from 0.69 for the decanter and 1.11 for the readler, the latter having a medium potential viscosity. The formation of alkali occurred in the readler and decanter, causing corrosion at these points. The calculations of the deposition rates, based on the elemental chemical composition of the ashes were able to express the problems that occur in the combustion of the forest biomass in the boiler.

Tobacco is traditionally used for cigarettes and cigars manufacturing and after the drying process a great quantity of dry tobacco stalks is treated as waste. In this framework, the scope of the paper is to examine the use of tobacco stems to feed a biomass boiler after a chipping process. The study is focused on southern Italy area thus, firstly, the assessment of tobacco availability in Italy and Campania region has been determined. Then, Burley tobacco stalks sampled out in an air-curing factory of south Italy crop have been characterized according to ASTM D5142 and ASTM D5373 standards. Thereby, biomass and natural gas fuelled boilers have been compared through an energy, environmental and economic analysis on simulative basis. Both systems satisfy the thermal energy demands of a multi-purpose condominium located in a cold Italian climatic zone near the factory. The results have demonstrated that boiler fed by tobacco chips ensures environmental and economic advantages compared to traditional system. In particular, it guarantees a reduction of CO2 emissions up to 16.59 tCO2 in one of investigated scenarios and a simple payback period and a net present value of about 5.6 years and 17,168 € (without economic support), respectively.

The aim of this work is to substantiate the possibility of increasing the technical, economic and environmental efficiency, as well as the efficiency of boilers (in terms of the intensity of corrosion processes) when burning water-fuel emulsions with the increased water and salt contents. To achieve these goals complex experimental studies were performed on the combustion of fuel oil and emulsions based on it, as well as the corrosion processes with a water content in the range from 2 to 30%, and a salt content ranging from 17 to 490 mg/dm3 hydrodynamic homogenizer. A significant result of the studies carried out is that with a water content of ~30% in the fuel gases composition, an NO2:NO ratio of 0,33 was achieved. That increased the absorption properties of gases and allowed passivation of carbon steel in sulfuric acid condensate. It also decreased the intensity of the low-temperature corrosion in the range of metal temperature of 130...70°C. All these made it possible to use condensation surfaces and to reduce the flue gases temperatures, to increase the efficiency of boilers, to ensure the economy of pure fuel, to increase the depth of utilization of the exhaust gases heat, and to reduce the concentration of toxic gases. The results obtained differed from those known. The significance of the results obtained lies in the fact that a technology was developed for the integrated use of the electrodialysis water resources, the waste and oil-containing waters, ensuring the operability of boilers, with a water content of emulsions of ~30% and a salt content of up to 450 mg/dm3.

This study sought to analyze the viability of the use of solar energy, for the operation in boiler economizers, in the replacement of the thermal energy of the exhaust gases. The experiment was divided in two steps: analysis of the boiler yield with different feed water temperatures and addition of the solar field to the initial set. For the modeling of the economizer-boiler set, the software used was Engineering Equation Solver (Software F-Chart, Wisconsin, USA). The technology chosen for the second stage was the high-pressure vacuum solar collector, installed at the inlet of the feed water heater. The thermal power of 2014W (per plate) and the solar radiation peak of 1000W / m² were standardized, taking into account the calculations for a steady state system at noon. The variable was the number of solar panels to be used at the plant. After analyzing the data, it was verified that the efficiency varied by approximately 7.4%, when the feed water temperature was increased by 20 ° C, close to 48 ° C. In order for this variation to occur, it was necessary to use 50 plates.

A method for designing salt equalization lines (SEL) in two-sided external saline compartments (SC) with allowance for natural circulation is described. If there is heat imbalance between the left and right SCs, the SEL cannot eliminate the salt imbalance between them because of the natural circulation in the two-sided SCs. The method was validated experimentally for TG-104 boiler with SELs: salt imbalance occurred between the SCs after artificial creation of heat imbalance between the left and right waterwalls of the saline compartments.

The results of studies of the effectiveness of using the air method of preventing condensation formation in the gas-exhaust ducts for anticorrosive protection of chimneys of gas-fired heating boiler plants are presented. This method is used in heat-recovery systems of boiler plants, characterized by deep cooling of gases (below the dew point temperature of water vapor contained in exhaust-gases). The essence of this method is to change the thermal and humidity characteristics of exhaust-gases after heat-recovery by mixing dry and heated air in front of the chimney. Schematic solutions of heat-recovery systems using two options for using the air method are presented. The first option corresponds to the use of the air method when mixing air from the heater of boiler plant. In the second option, for the implementation of the air method, air heated in the heat-recovery system itself is used. To assess the efficiency of the air method, computational studies were carried out to determine the thermal and moisture characteristics of flue gases at the mouth of different types of chimneys under different operating modes of the boiler during the heating period. The studies were carried out for two proposed options for using the air method when using air with a change in its temperature over a wide range. The values of the dew point of the flue gases at the mouth of the chimney and the temperature of its inner surface were calculated at various proportions of the mixed air. The parameters of flue gases and mixed air were determined, ensuring the absence of condensation in the chimneys. Based on the values of the obtained parameters, a comparative analysis of the effectiveness of the considered options for using the air method was carried out. It is shown that for heating boilers the use of this method is the most effective in complex heat-recovery systems when using recovered heat for heating return heat-network water and combustion air. Key words: gas-fired boilers, exhaust-gases, deep cooling, air method, thermal and humidity condition, chimney, anticorrosive protection

The internal combustion system of coal-fired boiler is a complex nonlinear system with large delay and strong coupling. The most basic requirement for the boiler combustion system is that the combu...

Soluble boron stabilises fine distributions of M23C6 carbides near grain boundaries (GBs) in 9Cr steel during creep, enhancing GB precipitation hardening, and suppresses the Type IV fracture in wel...

The present work focused on modeling the nitrogen oxides (NOX) generation characteristics based on the interpretable machine learning algorithm for an in-service coal-fired power plant. Computation...

Purpose: Boilers are some of the most critical equipment in many production process especially in refinery operations, as it is used in generating steam for different applications. Different types of boilers are available commercially and have comparative advantages over one another. The pot or kettle boiler is the foremost of these equipment and consists of an empty vessel with a secure lid and a burner that is the source of heating. Though overtaken in industrial applications by more modern designs, these simple boilers which are often batch process equipment are still useful for small production processes at low pressures. The work here developed design adaptation of these batch boilers for continuous vaporization of crude oil for artesian refining of the oil. Methodology: Physical and assay data of Bonnylight Crude Oil (BLCO) was used for the work from the library of ASPEN Technologies. Simple mathematical models were developed from interpretation of implicit phenomena of the boiler transformation process. The models were validated using ASPEN HYSYS process simulation software Version 10. Findings: Computational results of the models and simulation results gave good convergence except for the heat transfer parameter of the model which had almost 100% of the simulation value. Nevertheless, the models have good predictive capabilities Recommendation: The design adaption models herein developed can be deployed with reasonable accuracy for the heating of crude oil especially for small artesian operations. However, the study space of the subject matter can be expanded for better accuracy and reliability.

The article presents the results of the experimental studies of the ignition processes of mixed fuels “wood + coal” under conditions corresponding to the furnace spaces of the boiler units of TPPs. It has been established that under conditions of relatively low ambient temperatures, the time characteristics of the ignition process of coal and wood particles in the composition of the mixture differ significantly from the analogous characteristics for the ignition of single particles. It is shown that woody biomass significantly accelerates the ignition of coal, compared to the ignition of homogeneous coal (the delay time is reduced by 20–30%). At the same time, it has been found that coal particles significantly slows down the process of wood ignition (on average by 30%). The analysis of the distance between particles (d) has shown that d has a significant effect on the ignition performance. It was found that there is a certain “optimal” value of d, at which the ignition delay times are minimal. It is also shown that with an increase in the ambient temperature, the effect of the distance between particles decreases significantly. Based on the results of the experimental studies, a mathematical model has been developed for the ignition of wood-coal fuel particles, which differs from the known ones by a detailed description of thermophysical and thermochemical processes occurring in the porous structure of fuels and in a small vicinity of these particles. A comparative analysis of theoretical and experimental values of ignition delay times has shown their good agreement. An asymptotic analysis of the ignition time has shown that the entire induction period can be conditionally divided into two stages: fuel heating and direct thermochemical reaction. The fuel heating time takes about 90% of the entire induction period.

An analysis of the contractual loads of heat-consumption objects connected to one of the boiler houses of the Fuel and Energy Complex of St. Petersburg is presented. The analysis was carried out on the basis of the results of processing the readings of heat-metering devices installed at the subscriber inputs of apartment buildings located on the territory of St. Petersburg. The analysis was carried out of the consumption of heat energy for heating during the heating period of 2018/2019, and a comparison was made of the calculated and contractual loads of heat-consumption objects located in the area of operation of the considered source of heat energy. Change in the specific indicators of thermal energy in apartment buildings for heating depending on the series/types of buildings, their number of stories (taking into account the number of entrances), construction periods, and their heated area is shown. Examples of determining the calculated heat load for heating- and hot-water supply of heat-consumption objects according to the data array of general house heat meters, including within the schedule for regulating the supply of heat at the source. The coefficients showing the ratio of the calculated heat load of heat consumption subscribers to the contractual load were obtained. The reserve of thermal power for existing consumers of thermal energy and the source to which these consumers are connected has been identified. The average value of the coefficient, which is the ratio of the calculated heat load for heating to the contractual one, is 0.66, the averaged value of the coefficient, which is the ratio of the calculated heat load for hot-water supply to the contractual one, is 0.82.

The dominant source of energy in the hot water boiler house Stred I. in Velky Meder is geothermal energy, which is drawn from the VM -1 well, which was drilled in its courtyard in 2015. Based on documents and personal inspections of this boiler room, I created a geothermal circuit scheme of this hot water boiler room, where the experimental measurements took place. Part of this paper is a diagram of the geothermal circuit, a comparison of measured values ​​within a selected characteristic day for summer and winter operation in 2020. Finally, the operation of the usage of geothermal energy in the hot water boiler room Stred I. is evaluated on all these indicators.

In thermal power generation equipment, circumferential cracking in boiler tubes due to thermal cycling is a problem. Circumferential cracks form in the water-wall tube where sulfide corrosion occurs and in superheater and reheater tubes where high-temperature oxidation occurs. The main cause of the crack formations is thermal cycling, but sulfide corrosion and high-temperature oxidation also promote crack generation and accelerate crack progression. Therefore, preventing sulfide corrosion and/or high-temperature oxidation is one strategy for suppressing circumferential cracking. The authors previously developed a SiO2/TiO2/Al2O3-based/TiO2 coating for preventing sulfide corrosion and high-temperature oxidation on boiler tubes. In this work, to confirm the robustness and durability of the coating against circumferential cracking, laboratory experiments and exposure tests in actual power plants were performed. When applied to circumferentially cracked boiler tubes, the coating did not crack and suppressed growth of existing circumferential crack in comparison with an uncoated part.

The optimization of boiler soot blowing strategy and repair plan is investigated based on Hamilton–Jacobi–Bellman (HJB) equation in this paper. From the perspective of soot, we build a Markov process with three modes to describe the boiler running process. For the sake of applying HJB equation, a cost function is constructed according to the built Markov model, and HJB equation is derived by using optimality principle. The optimal soot blowing strategy and repair plan can be obtained by solving HJB equation. Particularly, the properties of value function, which are regarded as the optimality conditions, can ensure the existence and uniqueness of HJB equation solution. On this basis, Kushner method is used to overcome the difficulty of obtaining analytical solution of HJB equation. Moreover, numerical simulations are performed to verify the effectiveness of the proposed method and analyse the robustness of the obtained soot blowing strategy and repair plan when the system parameters vary.