Industrial Steam Boilers

To ensure the operational safety of an industrial water-tube steam boiler it is very important to assess various accident scenarios in real plant working conditions. One of the most challenging scenarios is the loss of feedwater to the steam boiler. In this paper, a simulation of the behavior of an industrial water-tube radiant steam boiler during feedwater line break accident is discussed. The simulation is carried out using the RELAP5 system code. The steam boiler is installed in an Algerian natural gas liquefaction complex. The simulation shows the capabilities of RELAP5 system code in predicting the behavior of the steam boiler at both steady state and transient working conditions. From another side, the behavior of the steam boiler following the accident shows how the control system can successfully mitigate the effects and consequences of such accident and how the evaporator tubes can undergo a severe damage due to an uncontrolled increase of the wall temperature in case of failure of this system.

Abstract. Thermal efficiency is an economical operation index of industrial boilers. There are many factors influencing thermal efficiency. It is difficult to keep the boiler in high efficient operation just using single automatic control method when environment has been changed. Therefore, the control of combustion systems is usually depended on artificial experience. To improve this situation, an operation optimization method is proposed. An identification model which can reflect the thermal efficiency is established by using principal component analysis based on historical data. When the boiler’s operation efficiency decreases, the parameters of influencing boiler efficiency can be directly got by contribution plot method, which can guide operators in real-time to adjust these parameters maintaining boiler efficient operation. Abstract. Thermal efficiency is an economical operation index of industrial boilers. There are many factors influencing thermal efficiency. It is difficult to keep the boiler in high efficient operation just using single automatic control method when environment has been changed. Therefore, the control of combustion systems is usually depended on artificial experience. To improve this situation, an operation optimization method is proposed. An identification model which can reflect the thermal efficiency is established by using principal component analysis based on historical data. When the boiler’s operation efficiency decreases, the parameters of influencing boiler efficiency can be directly got by contribution plot method, which can guide operators in real-time to adjust these parameters maintaining boiler efficient operation.

Boilers, or steam boilers, are crucial components in a variety of industries and applications, from power plants and chemical plants to building heating systems. Their primary function is to generate steam by heating water using a specific energy source (e.g., fossil fuels, biomass, or electricity). The steam produced is then used to drive turbines, heat industrial processes, sterilize, and for various other purposes. This research to quantitatively analyze the effect of variations in steam production on the operational efficiency of a small-scale boiler with a nominal capacity of 12 kg/hour. The experimental method is carried out by operating the boiler (a modified gas cylinder) at various levels or variations in steam production rates achieved by adjusting the fuel combustion rate, while maintaining the appropriate operating pressure. The main equipment of the experiment is an LPG gas cylinder modified as a boiler, a gas stove, a 3 kg LPG gas cylinder. The parameters measured include the fuel consumption rate, the actual amount of steam production, the feed water temperature, and the outlet steam temperature. The boiler efficiency at each steam production level is calculated based on the comparison between the energy contained in the steam produced and the input energy from the fuel. The first test with an absolute pressure of 300 kPa obtained an absolute temperature of 133.52°C and an efficiency of 84%. While the second test with an absolute pressure of 375 kPa obtained an absolute temperature of 141.3°C and an efficiency of 87%. For the third test, with an absolute pressure of 500 kPa obtained an absolute temperature of 151.83°C and an efficiency of 77.5%. The results of the study indicate a correlation between the amount of steam production and boiler efficiency, with the identification of a range of steam production rates that produce optimum efficiency with an efficiency of 87%. This information is crucial for the efficient operation of small-scale boilers, especially in applications with varying steam demand. It is hoped that this research can provide a real contribution in efforts to save energy, reduce operational costs, and minimize the environmental impact of the use of simple tube boilers in various industries.

Most researches regarding emulsified fuel were in the areas of emulsifier, emulsified fuel manufacturing and emulsified fuel droplet combustion, but there were little papers published regarding emulsified fuel combustion and boiler efficiency in an industrial boiler. The main purpose of this study is to clarify whether improvements in the boiler efficiency and the reduction of pollutants such as CO, NOx, SOx and smoke exist or not when emulsified fuels are combusted in the commercial boiler. Main experimental parameters were water content in heavy oil. excess O₂, and boiler load. The fuels used in this experiment were 0.5 B-C, and 5 kinds of 0.5 B-C/water emulsified fuels. The combustion characteristics of heavy oil and its emulsions with water were investigated in an industrial boiler. The combustion stability was monitored and exhaust gases such as CO. NOx. SOx and smoke were measured with excess O₂ and combustion load. In case of emulsified fuel combustion, flame stability was poor and boiler efficiency was lowered by 1.6-5.7%. but emission levels of CO and smoke were improved.

Energy exergy efficiencies and environmental effects of mixed fuelled (solid+gas) industrial facility steam boiler

Thermal–hydraulic simulation of a radiant steam boiler using Relap5 computer code

Previous researches often emphasize on the sources and effects of air pollutants in the environment and human population. A part of those studies were done in order to explore the spread or distribution pattern of those pollutants, especially regarding the emission from industrial steam boilers. It is very important to evaluate the transfer trend of air pollutants at both local and global scales. In this study, Industrial Source Complex Short Term Version 3 (ISCST3) model has been used to predict the distribution of NOx emitted from industrial steam boilers in the District of Hulu Langat, Selangor. The result of analyses indicates that the emission rates for steam boilers were ranging from 0.0083 kg NOx/hour to as high as 0.2771 kg NOx/hour while the total emission load was 1.9969 kg NOx­/hour. The evaluation on dispersion contour shows that the concentration of NOx was higher in 1-hour reading than 24-hour value. The highest concentration of NOx was predicted to be within 104.65 km2 from the sources of NOx (steam boilers).

The generation of black bottom ash, a byproduct of incomplete coal combustion, presents a significant challenge for coal-fired industrial boilers. This study investigates the potential of bottom ash as a supplementary fuel, with the dual purpose of enhancing fuel efficiency and reducing waste. Laboratory analysis confirmed the high calorific value of bottom ash, leading to a two-stage experimental approach. The first experiment conducted a comprehensive compositional analysis of coal-bottom ash mixtures using a single-factor experiment design across five compositions. The second experiment tested the performance of these mixtures in the real industrial boiler itself, employing a 23 factorial design to evaluate the effects of key factors – mixture composition, coal height, and mixing methods – on steam pressure. The study uncovered an optimal blend of 83.61% coal and 16.39% bottom ash, a coal height of 170 mm, and an innovative dual mixing approach both inside and outside the boiler. This configuration achieved an average steam pressure of 7.08 bar with external mixing and 7.01 bar with internal mixing, exceeding the critical threshold of 7 bar. These results demonstrate the feasibility of reusing bottom ash as a fuel while providing a practical approach to enhancing the efficiency and sustainability of coal-fired boilers.

The energy intensive nature of electric arc furnace (EAF) steelmaking necessitates that efforts to reduce greenhouse gas (GHG) emissions will affect steelmakers directly and/or through electric power producers. A model of GHG emissions from an EAF meltshop has been developed using the life cycle assessment approach. Direct and indirect sources of GHG gas emissions are estimated and ranked. Furnace combustion optimisation was evaluated in case studies conducted on a Canadian conventional EAF and a British scrap preheating `shaft' furnace. The analysis assumed 32 and 68% fossil fuel electricity generation, respectively. These case studies show that indirect GHG emission sources, in particular electricity generation, are more significant than direct emissions from the EAF. For the conventional EAF, offgas analysis and improved combustion control reduced electricity consumption by 40 kWh t-1, costs by US$1·05/t, and GHG emissions by 20 kg CO2-eq./t. For the shaft EAF, real time offgas monitoring and closed loop burner control reduced electricity consumption by 25 kWh t-1, costs by US$3·6/t, and GHG emissions by 15 kg CO2-eq./t. The case studies show that combustion optimisation using an EAF offgas analysis and combustion control system provides greater electricity, cost, and GHG reductions than previously reported in the literature.

China’s industrial boiler systems consume 700 million tons of coal annually, accounting for 18% of the nation’s total coal consumption. Together these boiler systems are one of the major sources of China’s greenhouse gas (GHG) emissions, producing approximately 1.3 gigatons (Gt) of carbon dioxide (CO2) annually. These boiler systems are also responsible for 33% and 27% of total soot and sulfur dioxide (SO2) emissions in China, respectively, making a substantial contribution to China’s local environmental degradation. The Chinese government - at both the national and local level - is taking actions to mitigate the significant greenhouse gas (GHG) emissions and air pollution related to the country’s extensive use of coal-fired industrial boilers. The United States and China are pursuing a collaborative effort under the U.S.-China Climate Change Working Group to conduct a comprehensive assessment of China’s coal-fired industrial boilers and to develop an implementation roadmap that will improve industrial boiler efficiency and maximize fuel-switching opportunities. Two Chinese cities – Ningbo and Xi’an – have been selected for the assessment. These cities represent coastal areas with access to liquefied natural gas (LNG) imports and inland regions with access to interprovincial natural gas pipelines, respectively.

Components in ultrasupercritical steam (USC) boilers will operate under significantly more severe conditions than current subcritical and supercritical steam boilers. Existing construction rules for power boilers lack design guidance or criteria to assess the adequacy of designs for USC conditions. A Department of Energy (DOE) project addresses this by evaluating advanced materials under conditions similar to potential USC service environments. The project focuses on six tubing alloys and four thick-section alloys. Testing is underway for pressurized tube bends, notched thick-section bars, fatigue, and thermal shock on thick-section tubing made of materials like CCA617, Alloy 230, and Alloy 740. Further testing is planned for pressurized tubes, dissimilar metal welds, and thick-section weldments. This paper summarizes the status of this initial testing program aimed at enabling USC boiler material qualification.

Chapter 8 - Furnace control and safety

In this study, pollutant gas emissions and combustion efficiency of LPG fuel burning in a steam boiler were investigated experimentally and compared with the diesel fuel-based results.Designed and manufactured of a new tangential swirl burner, and used for gaseous fuel combustion (LPG) in the boiler that was already designed to be operated with liquid fuel (diesel).The study involves conducting experiments using a broad range of equivalence ratios () and with three different diameter ratios (dr = 1/10, 1/15, and 1/20) (diameter ratios = The variable diameter of the burner is compared against the fixed diameter of the boiler).The volumetric ratios of CO 2 , CO as well as the HC content in the exhausted gases are measured and the boiler efficiency is predicted.The obtained results revealed that the replacement of the liquid fuel burner with the tangential swirl gas (LPG) burner is simple, inexpensive, and had no negative effect on the other parts of the boiler.In addition, the lowest pollutant gas concentrations detected in the exhausted gases and the highest boiler efficiency are obtained with a diameter ratio of 1/10.In comparison with diesel fuel combustion, the LPG fuel offered the cleanest combustion at approaching 1 and above, required less O 2 for complete combustion, and had the least HC content in the exhaust gases at the lean mixing area.Finally, the boiler efficiency operating with LPG fuel was higher than that obtained with diesel fuel for all equivalence ratios.

One of the main components in a steam power plant is a boiler, which has the function to produce steam. Boiler efficiency is defined as the ratio of the amount of heat energy of the fuel to produce steam compared to the amount of fuel input to the boiler. Changes in coal quality influence combustion system settings, boiler efficiency, and impact on the environment. Research with an experimental method is needed to adjust combustion air with a variation of load and O2 trim values to get a complete combustion and optimum boiler efficiency and to see the effect on temperature and emission of flue gas. This paper has presented the data experiments, analyzing the effect of variations of O2 trim on the thermal efficiency of the boilers, flue gas temperature, and emission of the flue gas: NOx, CO, and CO2. It can be concluded that using the 4100 kcal/kg calorific value of coal, the optimum value of O2 trim of boiler efficiency at 72, 80, and 88% loads is 2%. Boiler efficiency will increase as the load increases. Boiler loads at 72%, 80%, and 88%, the maximum boiler efficiency is 83.33%, 83.42%, and 83.49%, respectively.KeywordsBoiler efficiencyO2 trimFlue gasExperimental

One of the most important tools in steam production in the oil and gas industry is a boiler. Along with the increasing demand for steam, it is necessary to think about ways to increase the efficiency of the boiler. A boiler or steam boiler is a closed vessel-shaped device used to produce steam or steam. Boilers are designed to transfer heat from a combustion source. With Used the direct method (Direct Method) to calculate boiler efficiency. The pressure and temperature data of the feed water and steam is processed through the data interpolation process to obtain the enthalpy value of the feed water and steam enthalpy. Based on the calculation results obtained boiler efficiency results of 78.11%, 78.27%, and 79.75% with an average efficiency of 78.71%, and from the results of boiler efficiency calculations from the report of PT Pertamina RU III (Persero) obtained results of 89,75% in 1991. The efficiency of the above boiler has decreased by 11.04%. The decrease was caused by several factors, namely shells, valves, and instrumentation that had been eaten by age and damaged tubes.