Furnace Efficiency Research Articles

Digital Twin Learning Ecosystem: A cyber–physical framework to integrate human-machine knowledge in traditional manufacturing

As Industry 4.0 enablers, digital twins of manufacturing systems have led to multiple interaction levels among processes, systems, and workers across the factory. However, open issues still exist when addressing cyber–physical convergence in traditional manufacturing small and medium-sized enterprises. The problem for both traditional operators and the existing infrastructure is how to adapt knowledge to the increasing business needs of manufacturing plants that demand high efficiency, while reducing production costs. In this paper, a framework that implements the novel concept of Digital Twin Learning Ecosystem in traditional manufacturing is presented. The objective is to facilitate the integration of human-machine knowledge in different industrial cyber–physical contexts and eliminate existing technological and workforce barriers. This adaptive approach is particularly important in meeting the requirements to help small and medium-sized enterprises build their own interconnected Digital Twin Learning Ecosystem. The contribution of this work lies in a single digital twin learning framework for different traditional manufacturing scenarios that can work from scratch using a light infrastructure, reusing the knowledge and common condition-based methods well-known by skilled workers to rapidly and flexibly integrate existing legacy resources in a non-intrusive manner. The solution was tested using real data from a milling machine and a currently operating induction furnace with a maximum power of 12 MW in a foundry plant. In both cases, the proposed solution proved its benefits: first, by providing augmented methods for maintenance operations on the milling machine and second, by improving the power efficiency of the induction furnace by approximately 9 percent.

The Simulation of Biogas Combustion in Top Open Burner

The top open furnace is commonly used for the heating processes. The efficiency of the top open furnace is low due to the amount of heat wasted through the top open. This study was using ANSYS Fluent, a two-dimensional computational fluid dynamic (CFD) model that was used to build the top open furnace. Exhaust gas recirculation (EGR) was installed in the boiler in order to collect the exhaust gas and reuse it to dilute the oxygen supply. To check the combustion of low calorific gas (LCV) gas, which is biogas composed of 60% methane and 40% carbon dioxide by mass fraction, the computational study started with a standard combustion with EGR. Medium-sized mesh is used for the smoothing grid. This mesh uses inflation to enable the size of the cells and the stack element. The findings of the numerical sensitivity test show that the boundary conditions along the combustion chamber wall can affect the flame temperatures. The MILD regime was reached using biogas fuels when the right parameters were used.

A New Hybrid Supervisory Control System for Cabinet-Type Firebox Furnaces

In this paper, an intelligent hybrid Industrial Control System (ICS) and a Supervisory Control System (SCS) are proposed to improve the efficiency, safety, availability, and control capabilities of industrial furnaces. The main components of ICS are process control systems and advanced control systems that consist of overheating protection and load control. New soft sensors are designed as a combination of Laguerre filters and an artificial neural network to estimate the surface temperature of the furnace’s tubes, which allows the protection system to adjust fuel flow rate via overriding commands. Model-based fault detection systems are developed to detect faults in the combustion system and fouling in the furnace tubes and prepare features for the supervisory system. The supervisory control system is responsible for interfering between different components, evaluating the situation, and decision making based on the unit status and process conditions. An intuitionistic fuzzy inference system is employed as the core of the supervisory controller to tolerate disturbance and faults by switching the control modes. Test studies using experimental data of the furnace indicate the capability of the proposed monitoring and control system to operate in various loading situations and recover the system from abnormal conditions. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —In petrochemical industries, several reports have been issued about the load reduction of fired-heater furnaces imposed by combustion system faults and emergency shutdowns to carry out un-planned repairs due to fouling and wax-formation in tubes. Different activities such as detecting abnormal conditions, identifying faults, and enforcing corrective action can be performed by operators through manual actions. This paper is focused on designing a new supervisory control system (SCS) to be able to recover the fired heater furnace from abnormal conditions and keep running the plant. The SCS evaluates the condition of the unit by acquiring information from main variables, sensors, actuators, operating status of components and utilities, and operator commands. By identifying the root cause of faults, SCS makes decision on recognizing hazard degree, raising alarms, and applying automatic corrective actions.

Efficiency Improvement, Design Optimization, and Expansion of Oxygen Flow Valve Holes in Small Industrial Scale Husk Furnaces

Indonesia has an abundant amount of industry. Production in large, medium, and small industries still uses gas and oil as fuel sources. The fuel sources used still come from non-renewable energy. There is a need for alternative use of renewable energy to reduce the use of non-renewable energy. One solution is the use of rice husk biomass as a fuel source. Rice husk is still often considered as waste despite its many utilizations. The utilization of rice husk waste must be improved to increase its beneficial value. Rice husk waste can be utilized as a fuel source in a husk furnace. A husk furnace is a cooking device in which the fuel (rice husk) is burned using direct combustion. This research aims to optimize the efficiency of the husk furnace by varying the size of the oxygen flow valve hole and the mass of water being heated. Tests were conducted on four variations of oxygen flow valve hole size, namely, 36x27 cm2, 36x34 cm2, 43x34 cm2, and 50x34 cm2, and two variations of water mass (6 and 18 kg). The research was conducted by heating water using the Water Boiling Test method with test parameters: heating time, fuel consumption rate, energy in, energy out, heat efficiency, heat transfer rate, and ash and charcoal yield. The significant efficiency value can be used as a reference for small-scale industrial rice husk furnaces. The most significant efficiency in the study was 54.99%, achieved by a 43x34 cm2 valve hole for heating 18 kg of water. Based on the most effective efficiency value gained, the expansion of the oxygen flow valve hole is sufficient to be used as a test parameter to test the optimization of small industrial-scale husk furnaces.

“In situ” studies on cokes drilled from tuyere to deadman in a large-scale working blast furnace

The properties and deterioration of coke have a significant impact on the thermal efficiency, fuel consumption, and CO2 emissions of blast furnace. Coke sample drilling is one of the effective ways to investigate coke behaviors in a working blast furnace. However, previous coke sample drilling process involved compressed coke, which cannot accurately reflect the actual condition of coke in blast furnace. Therefore, “in situ” coke samples were drilled for three times from tuyere to deadman in their original positions within a large-scale working blast furnace in the present work. The results show that the coke particle size degradation reaches 85.36 % in the 0–5 m zone at the tuyere level. The proportion of coke size less than 3 mm increases sharply along the tuyere direction, and a new method of calculating the depth of the tuyere raceway zone is proposed for the first time. The study based on the grey relational analysis shows that the depth of the raceway is closely related to the blast volume and the blast kinetic energy. Main factors causing the degradation of coke in the tuyere level are fully revealed in different regions. It is suggested to reduce CaO and alkali metals brought in blast furnace in order to protect coke.

АНАЛИЗ РАБОТЫ ПЕЧИ ДЛЯ НАГРЕВА ВОДОРОДСОДЕРЖАЩЕГО ГАЗА

The article analyzes the efficiency of a vertical flare furnace used to heat hydrogen-containing gas in a hydrodealkylation plant. It was found that the furnace has low efficiency, the value of which is influenced by multiple factors. To increase the efficiency of the existing furnace, a com-prehensive solution was proposed, including the reconstruction of the coil, the fuel and oxidizer supply system, and the flue gas removal system

Mathematical modeling of the rotary furnace operations for the production of clinker

This paper presents a comprehensive system of mathematical models to describe, simulate, and optimize the operational and energetic aspects of rotary furnaces within the cement industry. To achieve this, we delve into the interaction between the furnace and other aggregates within the plant. We define the key variables governing the furnace’s operation through a meticulous analysis. Leveraging the power of genetic algorithms, we successfully validate the model’s performance under static and dynamic operational conditions. A pivotal aspect of our approach involves considering the behavior of combustion gases as analogous to a piston flow system. This consideration enhances our understanding of the complex processes occurring within the furnace. Furthermore, we establish shutdown criteria based on predetermined values obtained from the Case study facility: TR (Total Runtime) of 47 minutes, GT (Gas Temperature) at 97 percent, and ℵ (Agitation Speed) at 35 percent. These predefined values align with the desired outcomes of our objective function (Z). Through integrating and implementing our findings, a promising avenue emerges for improving the final product’s fuel consumption rate and quality. By concurrently addressing the plants and furnaces efficiency indicators, we set the stage for a more sustainable and productive operation in the cement industry.

Эффективность трубчатой печи в процессе стабилизации углеводородного конденсата на Астраханском газоперерабатывающем заводе

One of the most important and promising areas of Russia's development for the coming decades is the in-troduction of energy-efficient and energy-saving technologies. designated by the President of the Russian Federation. Currently, in Russia, various types of technological tubular furnaces with natural thrust are widely used at many gas processing plants and refineries. The bulk of tubular furnaces are operated by personnel without any automation systems and regulation of the supply of both fuel and air. The article discusses the issues of efficient operation of a tubular furnace during stabilization of hydrocarbon condensate with acidic components at the Astrakhan Gas Processing Plant. When designing a tubular furnace, various options for efficient operation with the utilization of the thermal energy of exhaust flue gases are considered. It is established that the maximum efficiency of a tubular furnace is obtained not only when the flue gas temperature at the outlet of the chimney is minimal, but depends on a number of factors that are discussed in more detail in this article.

Evolution and modification of physicochemical properties of coal-coke-slag powder within the tuyere bird's nest area of a blast furnace

Understanding the occurrence of phases and the evolution of physicochemical properties in coal-coke-slag powder within the blast furnace tuyere's bird's nest area is crucial for reducing carbon emissions and energy consumption in the blast furnace. By dissecting a 2200 m3 blast furnace in China, the temperature field and high-temperature physicochemical properties of coal-coke-slag powder in the tuyere bird's nest area along the radial direction were determined. Firstly, the temperature range in the tuyere bird's nest area spanned from 1523 °C to 1709 °C, with the maximum temperature near the end of the bird's nest area. Secondly, the mass proportions of coal, coke and slag in coal-coke-slag powder were 42.16 %, 25.90 % and 31.94 %, respectively. Along the radial direction of the blast furnace, the degree of graphitization of carbon components of coal-coke-slag increased gradually, and the melting temperature and viscosity of the slag phase also exhibited a gradual increase. Finally, the modification suggestions of the physicochemical properties of coal-coke-slag were put forward, with a focus on three factors: fuel, slag, and temperature. By employing tuyere injection operations with Ca-Fe flux, and using fuel with low ash content, larger particle size, fewer harmful elements, and excellent combustion performance, more heat input was provided to the front of the bird's nest area, which contributed to improved furnace efficiency and performance.

Determination of carbon-14 in marine biota using oxidation combustion and gel suspension liquid scintillation counting

In this study, we report a new analytical method for determination of 14C in marine biota utilizing oxidation combustion separation combined with CaCO3 suspension of precipitates for liquid scintillation counting (LSC). The main factors affecting the oxidation combustion efficiency of tube combustion furnace and the counting efficiency of the LSC were systematically investigated and optimized. Under the optimal combustion conditions, the combustion recovery of carbon ranged from 85.6 % to 92.4 % for five marine samples. And the method achieved a detection limit of 0.13 Bq/g for 14C and repeatability of 3.9–9.1 %. The analytical turnover time was 6 h, and up to six samples could be processed simultaneously. Assessment of uncertainty components showed that the uncertainty in counting was the largest contributor, followed by combustion recovery and counting efficiency. The developed method enables reliable measurement of 14C in marine biota, providing valuable analytical tool for risk assessment purposes.

Use of heat recovery technology to increase thermal efficiency of rotary furnaces

The article considers the problem of increasing the energy efficiency of rotary kilns, which are used in various industries for thermal processing of materials, such as metallurgical, chemical, construction, electrode and others. The source of heat for the kilns is gaseous fuel, which is supplied through special burners located at one end of the cylinder. The material for processing is loaded at the opposite end and moves towards the burner due to the force of gravity and rotation of the kiln. One of the important aspects of operating rotary kilns is energy efficiency, which depends on many factors and generally characterizes the degree of use of heat from fuel for heating the material. However, a significant part of the heat from fuel is lost through the kiln shell, which leads to an increase in fuel consumption and a decrease in kiln productivity. Therefore, it is necessary to look for ways to reduce heat losses and use part of the heat for other purposes. In this context, heating secondary air can be one of the important methods for increasing the thermal efficiency of rotary kilns, especially for kilns that operate in a mode for pyrolysis firing of materials such as coal, wood, peat, etc. The aim of the work is to increase the energy efficiency of a rotary kiln using a spiral heat exchanger, using the heat from the external shell of the kiln to heat secondary air. The paper proposes the use of a sectional heat exchanger, which can perform the functions of a cooler, a thermal insulator and a regulator of temperature regimes of the kiln. The heat exchanger consists of several sections that are attached to the outer surface of the kiln shell and have channels for air passage. The air is heated by contact with the hot shell and then supplied to the burner as secondary air. Thus, the heat exchanger allows to reduce the temperature of the shell and provide an additional source of hot air. A mathematical model for numerical calculation of a spiral heat exchanger has been developed, which allows to evaluate its thermal and temperature characteristics. It is shown that by using the heat from the shell it is possible to heat secondary air to a temperature of 270 °C in an amount sufficient to ensure the operation of the burner. An analysis of the location of the heat exchanger and the use of insulation coating has been carried out, which made it possible to significantly reduce its size without changing the total thermal effect compared to a heat exchanger installed along the entire length of the kiln shell. The effectiveness of using thermal insulation has been shown, which makes it possible to increase the temperature of air by 50 °C with its thickness 7 mm. The obtained results can be useful for further development and optimization of projects aimed at improving heat exchange systems and efficient use of thermal resources in rotary kilns.

Double-Circuit Adaptive System of Fuzzy Phase-Autonomous and Energy-Efficient Control of Arc Furnace Electric Modes

The article provides an overview of the existing structures of fuzzy model systems for arc length control and optimal control of arc steel-melting furnaces (ASFs) electrical mode. The analysis of known adaptive optimal control strategies of alternating current steel-melting arc furnaces modes according to complex criteria of energy efficiency, energy saving and reliability was performed. Expedient system engineering solutions are proposed for the comprehensive improvement of energy efficiency and electromagnetic compatibility of arc furnaces and the power grid, which are implemented by improving automatic power and arc length control systems. Control principles, indicators of arc length control dynamics, energy efficiency and electromagnetic compatibility of various systems are analyzed. The expediency of using fuzzy control models for comprehensive improvement of dynamics, energy efficiency and electromagnetic compatibility indicators is substantiated. The expediency of implementing simultaneous phase-independent control of arc lengths and fast-acting arc currents control is substantiated. A variant of the double-circuit structure of fuzzy arc lengths control system and implementation of the multi-criteria optimal control strategy of electrical modes (EM) is proposed. The design of fuzzy inference systems for the synthesis of the electrode movement control signal was carried out in order to improve the dynamic accuracy of the ASF electrical mode coordinates stabilization. A computer Simulink model of the developed double-circuit system was created, and studies of the dynamics and energy efficiency indicators when handling deterministic and random perturbations were performed. The obtained results of model studies showed an improvement of the control dynamics quality indicators under the influence of deterministic and random perturbations and an increase in the energy efficiency of ASF EM at various technological stages of melting. The expediency of the practical use of the proposed solutions for operating arc furnaces is substantiated.

МЕТОДЫ ЭНЕРГОСБЕРЕЖЕНИЯ ДЛЯ ТРУБЧАТОЙ ПЕЧИ

The main reasons for the low energy efficiency of tube furnaces are discussed. It was revealed that the main cause of heat loss is the inefficient use of the heat of flue gases. Ways to eliminate this problem are proposed

Increasing the Efficiency of Synthetic Iron Production by the Use of New Kit Lining

The production of synthetic iron castings in Russia comprises 50% of all alloys produced; therefore, increasing their smelting efficiency is an urgent task in the industry. This process depends primarily on the efficiency of industrial frequency induction crucible furnaces using acid lining. In the present study, the properties of quartzite, which forms the basis of such a lining, were investigated. An analysis of the proposed variants for changing the composition of the acid lining for use at temperatures of 1550–1600 °C was conducted. Following the preliminary temperature treatment of raw quartzite, which was then subjected to a sintering regime, we determined the conditions under which it was possible to obtain a phase state, allowing for the operation of the lining at temperatures above 1450 °C. We determined the use of an electrocorundum of two fractions as an additive to the traditional composition of the acid lining. The industrial testing of a new liner composition for the smelting of synthetic cast iron in an induction crucible melting furnace with a single steel scrap-metal filling was assessed, which required the use of an increased amount of carburizing agent. The positive results obtained can be explained by the study of the spent lining, which withstood 345 smelting methods of genophasic rent analysis. The results of the test are based on the results obtained in a study conducted on the finished coating of the product.

СПОСОБЫ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ РАБОТЫ ТРУБЧАТОЙ ПЕЧИ

The main reasons for the decrease in the efficiency of tube furnaces are considered. Methods to eliminate these causes are also proposed

Study on the Exergy Transfer Characteristics of the Heat Transfer Process of the Tube Heating Furnace

Abstract Aiming to describe the heat transfer process of tubular heating furnace from the angle of energy quality, an exergy transfer model of tubular heating furnace was established to evaluate the energy consumption level of heat furnace. The model is based on the 1-N heat exchange chain theory, innovatively combined with the transfer evaluation index. The temperature distribution in the furnace chamber is calculated by the mathematical model of the zonal method, and then the reduction rate of the heat transfer density and the resistance rate of the heat transfer are calculated. The results show that the exergy potential of the radiant furnace tubes during the heat transfer of the heat furnace is large, and the influences of both the blackness of the furnace wall and the coefficient of convective heat transfer of the exergy transfer of the radiant furnace tubes under steady-state conditions are discussed in detail. With the increase in the blackness of the furnace wall, the exergy density of the flue gas side of the pipe wall increases significantly. With the decrease in the coefficient of convective heat transfer, the exergy density of the working medium side of the tube wall decreases significantly. The energy efficiency of the heat furnace can be improved by adjusting the two parameters in engineering.

Procedure to Obtain Cu2O Isolate Films, Structural, Electrical, and Morphological Characterization, and Its Use as an Electrical Isolator to Build a New Tube Furnace

Copper oxide is a widely studied compound in wastewater decontamination, hydrogen production, solar cell production, and sensor fabrication. In recent years, many architectures and structures with the potential for developing clean technologies have been synthesized. A procedure by thermal oxidation to grow electrical insolate Cu2O films on copper surfaces in an air atmosphere was developed. The results of the morphological and structural characterization of the copper oxide layers evidence the presence of Cu2O polycrystalline films. The films have polyhedral architectures of approximately 1.4 μm thickness and are electrically insulating. A novel copper resistive furnace was built using this copper oxide film which was used as an electrical insulator between the electrical resistance of the heater and the surface of the copper thermal block. The application improves the efficiency of the resistive furnace in terms of the temperature reached and the thermal coupling response time relative to the performance of conventional furnaces using ceramic insulation. Over the entire operating temperature range explored for the same power supply, the copper oxide-coated furnace achieved higher temperatures and faster response times than the traditionally coated furnace.

ПІДВИЩЕННЯ ЕКОЛОГОЕНЕРГЕТИЧНОЇ ЕФЕКТИВНОСТІ СКЛОВАРНИХ ПЕЧЕЙ

The results of the experimental and computational studies complex on improving the thermal and environmental efficiency of gas-consuming glass furnaces of the regenerative type are presented. The proposed recovery heat technologies of the glass melting fu

EVALUATION OF FURNACE-02 EFFICIENCY USING THE HEAT LOSS METHOD IN REFINERY UNITS AT PUSAT PENGEMBANGAN SUMBER DAYA MANUSIA MINYAK DAN GAS BUMI CEPU - JAVA

The production or processing of crude oil at PPSDM Migas Cepu using an atmospheric distillation system, which is a method of separating petroleum fractions based on differences in the boiling points of each fraction under atmospheric conditions. Oil processing at PPSDM Migas Cepu first raises the temperature by using a Heat Exchanger and Furnace to obtain the desired feed temperature or temperature. Furnace is heating equipment for processing petroleum which requires the largest operational costs in its processing business. Furnace-02 at the Refinery Unit at PPSDM Migas Cepu is more than 100 years old, and is still operating today. In petroleum processing, the furnace is very important because the furnace is a heat exchanger, which functions to raise the temperature of the petroleum before it is separated in the fractionation column. This study aims to evaluate the efficiency value of furnace-02 from calculations using the heat loss method. Furnace efficiency calculations must be carried out periodically in order to determine furnace performance so as to avoid long-term damage that can lead to maintenance. If the feed that enters the furnace is not in accordance with the specifications, it can burden the furnace's performance. From the results of calculations using the heat loss method, the performance of the furnace-02 at PPSDM Migas Cepu is 86.16%.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ЭФФЕКТИВНОСТИ РАЗЛИЧНЫХ МОДЕЛЕЙ ЭЛЕКТРИЧЕСКОГО КОНТУРА ЭЛЕКТРОДУГОВОЙ ПЕЧИ ДЛЯ ИСПОЛЬЗОВАНИЯ В ЦИФРОВОМ ДВОЙНИКЕ

usRelevance Nowadays the metallurgical industry is rapidly developing, which requires a continuous search for innovative solutions aimed at providing consumers with high-quality metal products in the required volumes. To achieve this goal, modern enterprises are faced with a number of scientific and technical tasks, which include increasing the energy efficiency of production. An innovative tool in this case is the development of methods for the digitalization of production, including implementation of digital twins for the control of complicated technological systems. The most energy-intensive equipment at metallurgical enterprises is electric arc furnace (EAF). As operating experience shows, control systems for electrical modes of such units do not always allow EAFs to operate with optimal time, energy and technological parameters, which in turn leads to increased operating costs, such as increased specific energy consumption, consumption of electrodes, etc. As a solution to this problem, a number of scientific studies propose the use of a digital twin for dynamic adaptation of the parameters of the EAF electrical mode control system, capable of calculating the settings of control algorithms during the melting process in such a way as to obtain optimal electrical and technological modes at different stages, as well as optimal dynamic performance quality of impedance regulation on the secondary side of the furnace transformer. One of the important stages in this case is the form of representation of the electrical circuit inside of the digital twin, since the adequacy of the output parameters and the accuracy of the operation of the entire control system will depend on this. Based on the above, an urgent task is to develop an effective method for modeling the electrical circuit of the electric arc furnace for application in a digital twin. Aim of research The paper is devoted to the results of research aimed at the use of various mathematical models of the electrical circuit for application in electric arc furnace’s digital twin. Research methods To process the experimental data, mathematical modeling methods were used in the Matlab environment with the Simulink application. All studies were carried out on the basis of experimental data obtained at operating equipment at domestic and foreign metallurgical plants. Results The significance of the research results lies in increasing the energy efficiency of arc steel-smelting furnaces through the use of a digital twin. This solution will allow to provide the optimal selection of transformer tap reactor tap and operating curve number for each stage of melting, as well as analyze the position of operating points on the electrical characteristics and generate additional control signals for dynamic correction of the lengths of electric arcs. The methods of electric circuit modeling in digital twins presented in the work allow to configure the melting program and optimize the parameters of nonlinear impedance or conductivity controllers of the secondary side of the EAF’s transformer. In addition, it makes possible the analyze and adaptation of the auxiliary blocks in control system — arc ignition, current control and correction of regulator setting signals as a function of the voltage deviation on the primary side of the furnace transformer (relatively to the rated value). Problems associated with calculating matrices of settings for impedances and conductances of the secondary circuit of an EAF for all combinations of transformer taps, reactor taps and all values of operating curves can also be solved. Mathematical models are implemented in the Matlab software environment with the Simulink application.