Boiler Operation Research Articles

Analysis of the Impact of Forces in Hanger Rods on Power Boiler Operation

Hanger rods intended for boiler suspensions on a metal structure require a special design approach that considers the total weight of the boiler structure that is to be carried. Unfortunately, a large reserve in the rods’ carrying capacity does not always guarantee the failure-free operation of a boiler. For this reason, it is very important to monitor the forces acting in the rods. Any negligence in this matter might cause a local excess of stresses in the boiler pressure part and result in periodic shutdowns of the boiler. Therefore, in order not to let this happen, adequate computational methods have to be developed. To date, the methods described in the literature and in design requirements have concentrated, first of all, on analyses of the boiler individual subassemblies or on small boiler units supported from the bottom at just a few points. The aim of this paper was to conduct a numerical analysis for a real high-capacity power boiler. The computations were performed based on experimentally measured forces in the hanger rods, and the results were verified by comparing the areas of stress concentration against the area where the boiler structure was regularly damaged.

Modeling and prediction of key parameters of circulating fluidized bed boiler based on Transformer

BackgroundA data-driven approach that integrates Transformer and convolutional neural network is proposed to address the challenge of traditional data-driven models, which often exhibit significant deviations in predicting continuous processes. MethodsThe proposed method uses the operating data of a circulating fluidized bed boiler over a specific time period as the input for the model. Firstly, the Transformer is used to extract dynamic features from the first half of the input data. Then, the real-time feature expression is enhanced in the second half of the input data by combining it with the convolutional neural network. Finally, the fused feature is obtained using the deep neural network and utilized to predict key parameters. Significant findingsThe experimental results show that fusing the features extracted by the Transformer and the convolutional neural network can reduce the impact of boiler operation time delay and ensure better performance.

Investigating fouling deposition during combustion of hydrothermally treated palm empty fruit Bunch: Pilot-Scale study for industrial hydrothermal reactor

Inorganic elements in palm empty fruit bunch (EFB) are problematic in boiler operation, causing slagging and fouling deposits. The first pilot-scale hydrothermal treatment (HTT) system was commenced in a palm oil mill to remove undesirable elements. Fuel properties, combustion behavior, and fouling deposition of HTT-EFB were investigated. Liquid temperatures and treatment times in the HTT system significantly altered EFB-fuel properties. At ≥ 60 °C, potassium removals of at least 78 % were achieved, generating EFB-fuel containing potassium below 0.5 %wt. Later, a series of EFB combustion experiments were conducted in a specially designed fixed-bed reactor to simulate the tube surface of industrial boilers. Fouling deposition from HTT-EFB combustion reduced to below half of untreated EFB at all HTT conditions and combustion temperatures studied. The deposit-to-fuel ratio of HTT-EFB combusted at 1,000 °C was 37.3 % lower than untreated EFB combusted at a typical EFB boiler at 800 °C. Results demonstrated great potential for HTT-EFB in industrial applications.

Research and application of low-frequency eddy current detection technology for heating surface tube of power plant boiler

Abstract In this paper, an ultra-low frequency magnetic detection method for the shedding of oxide layer on the inner wall of austenitic stainless steel heating surface tubes in power plant boilers and a far-field eddy current automatic detection method for water-cooled wall tubes are introduced. The probe selection, comparison sample making, detection voltage, detection current, signal phase and amplitude of ultra-low frequency magnetic detection, and far-field eddy current automatic detection methods are tested and studied, which provide reference detection parameters for practical detection applications. According to on-site practical application verification, this detection method can quickly, intuitively, and accurately detect the oxide layer peeling off the inner wall of austenitic stainless steel pipes and the defects on the inner and outer walls of water-cooled wall pipes, providing a feasible and effective means for the quality supervision and safe operation of the power plant boilers.

Comprehensive Inspection Solution for Boiler Water Wall Tube Corrosion

A substantial number of domestic coal-fired boilers, most of which have been in operation for numerous years, are susceptible to corrosion and tube ruptures within their high-temperature environment, often resulting in unplanned shutdowns. Despite the annual planned maintenance shutdowns, which involve routine inspections of water wall and furnace tubes to detect potential corrosion and erosion, the current non-destructive testing methods are generally localized. This approach, particularly with the considerable height variation of the water wall tubes (ranging from approximately 10 to 25 meters), may overlook segments with severe corrosion during localized ultrasonic thickness gauging. Although the experience of inspection teams reduces the chance of defect oversight, the demand for a comprehensive and effective inspection technique remains a priority for boiler operators. This study utilizes the characteristic of guided waves to propagate over a certain distance along pipelines, initiating an exploration into a comprehensive inspection solution for water wall tubes. Finite element simulation results demonstrate the suitability of utilizing a 120 kHz frequency for shear horizontal mode (SH0) testing on the fire side of water wall tubes. This mode effectively screens for localized corrosion within a 3-meter range. In the field of on-site boiler inspection, electromagnetic coils are employed to generate guided waves within water wall tubes. The gathered signals from each electromagnetic guided wave testing (EMGWT) are consolidated into a distribution map, indicating suspicious signal locations. Pulse eddy current testing (PECT) is employed to identify potential issues with guided waves without requiring surface preparation. If PECT reveals anomalies, the affected surface is polished, and phased array ultrasonic testing (PAUT) is conducted to quantitatively measure the remaining wall thickness due to corrosion. The theoretical exploration and on-site inspection outcomes affirm the feasibility of this approach, aimed at enhancing operational safety for boiler water wall tubes and mitigating the risks of tube ruptures and leaks. This comprehensive inspection solution amalgamates three advanced detection technologies, each capitalizing on its unique inspection characteristics to facilitate corrosion screening, corrosion scanning, and wall thickness sizing. Through the integration of these technologies, the overall inspection strategy ensures the utmost level of reliability.

Enhancing Resistance to Corrosion, Erosion and Oxidation of Boiler Steels by Surface Modification Techniques

In coal based thermal power plant, the boiler components (superheater, combustion chamber, superheater tubes, boiler walls, reheater etc.) are subjected to harsh environment characterized by high temperatures, aggressive combustion products, and abrasive particles. Corrosion, erosion, and oxidation relentlessly reduce their lifespan and efficiency, posing significant economic and safety concerns. This review explores the potential of surface modification techniques to act as a valiant shield against these destructive forces, extending the life, enhancing the performance, and ensuring the safe operation of boiler components. In this articles various surface modifications techniques including their merits and demerits are discussed with emphasis on thermal spray techniques. From established methods like thermal spraying and laser cladding to innovative approaches like nanocoatings and electrochemical treatments, each technique is meticulously examined for its effectiveness in boosting corrosion resistance, mitigating erosion wear, and minimizing oxidation at crucial boiler locations. This review culminates in a compelling vision of the future, where sophisticated surface modification techniques become an integral part of boiler design and maintenance strategies. By harnessing the power of these technologies, we can usher in an era of more efficient, reliable, and sustainable boiler operation, safeguarding investments and protecting the environment.

Modeling of Unburned Carbon in Pulverized Coal-Fired Supercritical Steam Generators

ABSTRACT In coal-fired boilers, one of the most important metrics for optimizing combustion is the proportion of unburned carbon (UC) in the ash. In most Indian power plants, it is still assessed offline through manual sample collection and laboratory analysis. The laborious processes of sample collection, preparation, analysis, and reporting require at least five to eight hours of work. The delayed results may not be useful to optimize combustion in the boiler furnace, as the boiler operating conditions may be completely different from the conditions when the samples were collected. Instead, the use of prediction algorithms may bring timely corrective action if the UC goes high. The present experimental study is taken up to obtain a correlation between UC and corresponding relevant boiler operational parameters and on the residence time of coal particles in the boiler furnace. Multiple regression analysis is performed using ANOVA tools. One hundred and ninety-four sets of coal, ash samples and boiler operating parameters are collected from 07 supercritical units. Coal proximate, coal fineness and ash UC analysis are carried out. The analyzed results and collected boiler operational data are statistically analyzed using Microsoft Excel’s ANOVA tool to understand the dependent behavior of UC on the boiler operational parameters and fired coal characteristics. The empirical equations are proposed for the prediction of UC in bottom and fly ash for supercritical boilers. Additionally, fresh 20 sets of coal, ash samples, and related operating data are gathered for the validation of the proposed empirical equations. For additionally collected samples, the predicted results are compared with the offline measured laboratory results. The maximum deviation between the predicted and laboratory results are within the range of ± 0.40% and ± 0.24% for bottom and fly ash samples, respectively.

A data-driven soft sensor model for coal-fired boiler SO2 concentration prediction with non-stationary characteristic

Environmental issues have received significant global attention, and achieving ultra-low emission has become a crucial goal for thermal power plant. Pollutant prediction is essential to achieving ultra-low emission control. Due to the frequent adjustment of operating conditions, the coal-fired power generation process is a typical non-stationary process with complex changes along the time direction. A single model cannot effectively portray the complex non-stationary characteristics and model mismatch may occur in the prediction, which brings new challenges for modeling coal-fired SO2 emission. Therefore, the condition-driven category boosting (CatBoost) soft sensor model is proposed for real-time prediction of SO2 concentration. First, the thermal process time series is rearranged into different data slices. These data slices vary along the direction of the condition indicator, which can characterize the process characteristics on different slices. Second, the load-based sequential condition division (LSCD) algorithm is designed to realize the division of boiler operation process. The characteristics of process are effectively captured by variational auto-encoder (VAE), and the data slices with similar process characteristics are merged into the same mode. Non-stationary process along the time direction is reorganized into different condition modes along the load direction. Finally, the high-resolution local CatBoost models under different modes are constructed to achieve fine-grained prediction of SO2 concentration. The effectiveness of the proposed condition-driven model is verified by an industrial example of 1000 MW coal-fired boiler. The prediction results show that the proposed model can effectively divide the operation conditions and achieve accurate prediction of SO2 concentration. In the typical models in SO2 predicting, the proposed model has better performance with a determination coefficient of 0.92.

Identifikasi Potensi Bahaya pada Stasiun Boiler Menggunakan Metode Hirarc di PT. Syaukath Agro

PT Syaukath Agro is a company operating in the Agribusiness Sector which is engaged in processing palm oil Fresh Fruit Bunches (FFB) into crude palm oil (CPO), Palm Kernel (PK) and shells. The palm oil processing system consists of several stages starting from receiving Fresh Fruit Bunches (FFB) to becoming palm oil or Crude Palm Oil (CPO). The palm oil processing process can be used in several stages carried out at each station. Based on interviews conducted, each station has a different level of risk of accidents, one of the stations that has a large risk of work accidents is the boiler station which is the heart of a palm oil factory where the steam boiler is the source of power and the source of the steam that will used to process palm oil. Boilers have potential dangers or risks when operated. The risks that often occur are falls, slips, burns, scalds, heat, noise, so it is very important to supervise and provide guidance regarding work safety. The size of the accident caused will certainly have a detrimental impact on the company. The severity of the accident can be determined through identification of potential dangers and risk assessment of all boiler operating activities at PT. Syaukath Agro. Based on the results of research conducted using the hirarc method, potential hazards found in boiler stations include: Unergonomic Working Attitudes, Noise Levels >84 dB with 8 Hours/Day Exposure, Working climate temperature (hot) 31°C on exposure >8 working hours/day, and oil buildup. Types of risk of work accidents at boiler stations consist of: Falls, injuries (slipping, slippery floors) Burns (in contact with hot objects around), Heat exhausting (Heat), Work accidents (fatigue ), hearing loss (noise), blisters (burns), health problems (muscles, bones), contact dermatitis (exposed to dangerous toxic radiation). Based on the results of risk control, it was found that the most appropriate type of control recommendation is administrative control and compliance with the use of personal protective equipment (PPE). Administration (Administration Control) is carried out by creating or providing a work system that can reduce the possibility of someone being exposed to potential dangers. The hierarchy of control of Personal Protective Equipment (PPE) is used to provide a boundary between exposure to the body and the potential danger received by the body.

Three-Dimensional Transient Electric Field Characteristics of High Pressure Electrode Boilers

An uneven electric field during the operation of an electrode boiler will lead to the emergence of a high field strength area and low field strength area in the furnace, which will endanger the safe and reliable operation and heating efficiency of the electrode boiler. A numerical study of three-dimensional transient electric field distribution characteristics in a 10 kV high-voltage electrode boiler was carried out. The distribution characteristics of the global electric field of the electrode boiler under the nominal voltage of 10 kV were studied, and the distribution law of the electric field of the electrode boiler under poor power quality, such as different bus voltage and three-phase voltage imbalance, was explored. The results show that the electric field distribution characteristics of the three-phase transient are more obvious in the section closer to the electrode disc, and the electric field distribution is the most uniform in the section that is 1.4 m away from the furnace water. In the case of poor power quality, such as different bus voltage and three-phase voltage imbalance, the points of the maximum electric field intensity of the four surfaces change periodically with time, and the greater the bus voltage fluctuation, the more severe the impact on the transient electric field. The three-phase voltage imbalance will shift the peak value of the electric field intensity. The decrease or offset of electric field intensity in the electrode boiler caused by poor power quality will directly affect its heating efficiency. The electric field simulation results have a specific reference value for improving the internal electric field distribution and on-site operation and maintenance of the electrode boiler.

Numerical simulation of the co-firing of pulverized coal and eucalyptus wood in a 1000MWth opposed wall-fired boiler

Currently, coal-fired coupled biomass power generation is widely regarded as a primary method for reducing carbon emissions in coal-fired power plants. This research investigates the co-firing of biomass in an opposed wall-fired boiler and the implementation of air-staged combustion technology using numerical simulation approaches. The study examines the impact of various air methods of distribution and blending ratios on combustion properties and NOx emissions. The findings demonstrate that the abrasive wear of fuel particles on the platen superheater is decreased by the addition of biomass to the fuel mix. Furthermore, a drop in the furnace chamber's overall temperature is the outcome of raising the blending ratio. Different blending ratios have their own adapted air distribution methods. At blending ratios of 10% and 30%, the W-type air distribution exhibits the lowest NOx outlet concentrations of 231.84 mg/Nm3 and 220.6 mg/Nm3, respectively. Moreover, the W-type air distribution shows the highest burnup rates of 98.74% and 98.43% at these blending ratios. This suggests that it is feasible to change the burner monolayer air distribution and combine it with co-firing of biomass technology to achieve low NOx and efficient operation of a hedge-fired boiler.

The clay-shoveler’s fracture, a rare occupational injury in the modern era: a case report

BackgroundThe clay-shoveler fracture, named after Australian clay shovelers from the 1930s, results from high-energy, repetitive pulling mechanisms and is commonly associated with shoveling or digging. This injury primarily affects the lower cervical and upper thoracic vertebrae, particularly the C7 and T1 vertebrae. The avulsion mechanism, caused by stress on the spinous processes, may lead to sudden, severe upper back pain, limiting the affected individual’s ability to work effectively.Case presentationThis report presents the case of a 27-year-old boiler operator who experienced persistent neck pain, which did not respond to conservative management. Imaging studies revealed a T1 spinous process fracture with associated soft tissue edema, diagnosed as a clay-shoveler fracture. Conventional treatment with a semirigid cervical collar, analgesia, and rest was administered, leading to a favorable outcome.The clay-shoveler fracture, though rare, should be considered in cases involving repetitive stress on the cervical and thoracic spine, especially in occupations that require heavy lifting. In most instances, conservative management proves effective in relieving pain and enabling recovery.ConclusionRecognizing the clay-shoveler fracture is crucial for timely diagnosis and treatment. This case report underscores the occupational nature of the injury and its association with specific work activities. Further research and reporting of similar cases will contribute to a deeper understanding of this unusual fracture pattern, its risk factors, and optimal management strategies.

Boiler Combustion Adjustment and Economic Operation Affect Boiler Combustion Factors

Thermal power generation, as the most stable power output in China, plays a rather crucial role in the construction of China's economy. The most important power generation equipment of thermal power plant is the boiler, only good control of the boiler operation of the power plant, in order to better enable it to participate in the power generation work. Combined with the Linfen Thermal Power Co., Ltd. related boiler unit operation status, combustion adjustment optimisation content analysis, give the corresponding recommendations, so as to make the boiler operation more stable, safe, environmentally friendly, power plant power generation to make the corresponding contribution.

Ash melting behaviors of high-sodium coal and its co-combustion with coal gangue to inhibit slagging

Fouling and slagging are major challenges that impede the clean and efficient use of high-sodium coals (HC) for power generation. To address these persistent issues, this study examined the impact of sodium (Na) on ash-melting behaviors and assessed the feasibility of mitigating fouling and slagging through the co-combustion of HC with coal gangue (CG). The mineral transformation mechanisms were analyzed through experimental and thermodynamic calculations using the FactSage software. The potential for inhibiting slagging through the co-firing of HC with CG rich in silica (SiO2) and alumina (Al2O3) was also investigated. The presence of Na-containing species led to the formation of more flexible minerals and lowered the ash fusion temperatures (AFTs). Na not only decreased the initial temperature required for the formation of the liquid phase but also increased the proportion of the liquid phase during high-temperature ash-melting processes. Co-firing with CG rich in silica and alumina significantly improved the AFTs of HC. Furthermore, this approach effectively reduced the propensity for fouling and slagging. In practice, it is recommended to control the co-firing ratios of CG within 10–30% to inhibit slagging and fouling issues while maintaining a smooth boiler operation.

Research on the Green Environmental Protection Method of Automatic Potentiometric Titration of Organic Heat Transfer Fluids Acid Number

This paper presents the concept and importance of acid number. Improvement method is based on the GB / T 7304-2014 “Standard test method for acid number of petroleum products by Potential Titration”. The detection and study of the acid number are obtained by halving sample volume in two categories—used and unused heat transfer fluids. This article studies and establishes a green and environmentally friendly method for automatic potentiometric titration of organic heat carrier acid value, which uses a smaller sample volume and titration solution volume to achieve fast, environmentally friendly, intelligent, and efficient results. The experimental results show that after halving the sample volume, the data reproducibility is relatively high, but still within the standard reproducibility range, and data of the heat transfer fluids is far less than the standard reproducibility range. Through this paper, the acid number of heat transfer fluids is able to be strictly controlled and timely monitored to ensure the safety, green environment development and operation of boilers and systems.

Влияние химического состава биомассы на процесс агломерации в псевдоожиженном слое котлоагрегата Е-75-3,9-440 ДФТ

The combustion of biofuels in the fluidized bed is an attractive technology to process biomass. However, the technology of biomass combustion in fluidize beds is characterized by several problems associated with the agglomeration of bed material. The aim of the research is to study the influence of the chemical composition of biomass on the agglomeration process of the fluidized bed of the boiler unit E-75-3,9-440 DFT. The boiler burns a mixture of by-products of pulp and paper production to increase stability of the fluidized bed and the duration of boiler operation between periods of its deslagging. The study has tested two types of biomass burned in a mixture in a steam boiler unit E-75-3,9-440 DFT with a fluidized bed. The authors also have studied the samples of agglomerates, bed, and fly ash to find out more about the agglomeration process. The elemental composition of samples of bark-wood waste, sewage sludge, agglomerates and ash has been studied. Elements affecting the process of agglomeration of the fluidized bed have been identified. The results of the analysis have showed that essential ash- and slag-forming components in the sewage sludge are silicon, calcium, sulfur, and potassium, and in the bark wood waste the essential ash- and slag-forming components are calcium, potassium, and sodium. The main elements influencing the process of agglomeration of the fluidized bed are alkaline elements of potassium and sodium. The results obtained make it possible to predict the agglomeration of the fluidized bed, to select the fuel mixture in the proportion necessary to reduce the agglomeration process.

Hybrid modeling of a circulating fluidized bed boiler for development of a prediction and prescription system for power plant operation

A novel hybrid modeling system of a circulating fluidized bed boiler was developed in this study. The proposed approach combines a computational fluid dynamics model, practice-oriented macro-scale models, and a data-driven reduced order model to capture both the physical and empirical behaviors of the boiler. The application of various modeling strategies allowed for capturing features of the simulated process at various scales and for developing a fast and accurate prediction system. The use of the computational fluid dynamics model improved the predictions of the practice-oriented macro-scale models providing more detailed flow information and the use of the reduced order model allowed for reducing the computation time by a factor of 1350. The hybrid model and its submodels were validated against real measurement data. The validation confirmed good accuracy in predicting key process variables. The developed model is used as a prediction and prescription system to enable operators to optimize the boiler operation and prevent abnormal events. The hybrid system is used for a supercritical, once-through boiler in Łagisza power plant in Poland, however, the presented modeling strategy can be applied in other power plants, which can improve efficiency, reduce emissions, enhance boiler availability, and ultimately contribute to more sustainable energy systems.

МЕТОДИКА ОПТИМИЗАЦИИ РАБОТЫ ЭНЕРГООБЪЕКТОВ ВОИНСКИХ ЧАСТЕЙ В АРКТИЧЕСКОЙ ЗОНЕ РОССИЙСКОЙ ФЕДЕРАЦИИ

Reliable energy supply to military consumers directly affects the security of the country. That is why it is necessary to develop an energy system that would meet the requirements of new realities. 
 One of the main tasks facing the Armed Forces of the Russian Federation is the protection of State sovereignty and the preservation of security in the Arctic zone. In order to maintain the combat capability and combat readiness of a military facility, it is necessary to provide it with fuel and energy resources in a timely manner. The issue of optimizing the operation of boilers is relevant today and requires the search for new solutions. This methodology takes into account criteria of different types: periodic (cyclic) and random. All factors have varying degrees of influence on the choice of the optimal strategy for optimizing the operation of an energy facility. As optimization measures, the methodology considers the expediency of converting boiler houses from diesel fuel to gaseous fuel.

Steam Boilers in Ready-Made Garments Industry in Bangladesh: Existing Scenario and Scope for Development

Bangladesh's Ready-Made Garments (RMG) industry, historically prone to hazards including boiler explosions with numerous fatalities, has prompted the RMG Sustainability Council (RSC) to initiate boiler safety inspections. This study addresses the lack of empirical data on boiler operations in RMG factories, focusing on operational scenarios, risk factors, and remediation strategies. Conducted from March 2021 to March 2023, structured visual inspections across 1386 RMG factories assessed 2204 boilers. Key findings reveal that 34.99% of factories predominantly use a single boiler, 91.24% of boilers are government-registered, and the majority are imported (63.29%) with a steam generation capacity below 1,000 kg/hr (59.75%). Additionally, 63.11% were manufactured between 2010 and 2019, 79.63% burn fossil fuels, 54.60% are vertically oriented, and 82% use softened feedwater. The study also identifies 32 external risk factors across 11 categories, providing insights for decision-makers to enhance boiler operation safety and sustainability. By leveraging this inspection data, the research aims to bridge the empirical gap and offer a comprehensive understanding of the existing challenges in RMG boiler operations. Journal of Engineering Science 14(2), 2023, 89-105

Modeling of the removal of combustion products in the pipe of a low-rise building as a control object

The features of the formation and methods of preventing condensation in the chimney of an apartment low-rise building with an individual decentralized heat supply system are considered. A mathematical model of the technological process of removing flue gases from gas boilers in an apartment building through a collective chimney pipe as a multidimensional control object with distributed parameters, which is understood as a set of thermophysical processes occurring during the removal of combustion products. Numerical simulation of a collective chimney pipe is performed on the example of a three-storey apartment building with gas boilers installed in each apartment as a control object. A method of step-by-step experiments is proposed. At the first stage, the dependences of the distribution of the temperature field inside the chimney during non-stationary operation of boilers and changing ambient temperature are obtained. The phenomenon of condensate occurrence has been confirmed experimentally, and the most characteristic areas subject to its occurrence have been identified. During the second stage of research, it was found that it is most effective and economically feasible to prevent the formation of condensate by using a heating cable in the attic and chimney head sections. It is shown that the change of control actions has an effect on the temperature of adjacent sections of the chimney. The revealed non-stationarity is taken into account by inter-channel connections through the object in the block diagram. It is proved that, in relation to solving the problem of removing combustion products from the chimney, an object with distributed parameters can be represented by a model with concentrated parameters, for which the structure is synthesized and proper operators and operators of inter-channel connections are found in the form of transfer functions with variable parameters. The resulting model is problem-oriented to create a two-dimensional automatic temperature control system on the inner surface of the chimney in order to prevent the formation of condensate in the pipe.