Heating Furnace Research Articles

Thermal conductivity of alumina-carbon composite brick and its related phase analysis in a dissected blast furnace

Excellent performance of refractories in blast furnace hearth is one of the important factors to ensure longevity of blast furnaces. As an emerging refractory for application in blast furnace, alumina-carbon composite brick combines the superior properties of carbon and alumina. Firstly, the thermal conductivity of alumina-carbon composite brick was measured by the laser flash method and the new device method to verify the feasibility of the new device method for thermal conductivity measurement. Secondly, the influence of heating temperature of the heating furnace and cooling water flow on the thermal conductivity of the alumina-carbon composite brick, and the comparison of the thermal conductivity of carbon brick, alumina-carbon composite brick and corundum brick were investigated to confirm the heat transfer mechanism of alumina-carbon composite brick. High thermal conductivity and erosion resistance to slag and hot metal of the alumina-carbon composite brick are consequent from: (a) reasonable composition combination of Al2O3, C, SiO2, SiC, etc., (b) dense structure, small pore diameter, and uniform distribution of the pores, (c) the generated SiC whiskers and Al6Si2O13, which can fill in the pores and reduce the porosity. Finally, the analysis on the phase distribution of the alumina-carbon composite brick in a dissected blast furnace was performed to illustrate the relationship between the erosion resistance and the thermal conductivity of alumina-carbon composite brick.

Design and Research of the Intelligent Water Temperature Monitoring System

In the industrial production process, people need to detect and control the temperature in various types of heating furnaces. The equipment selected for the water temperature control system designed in this paper is a single-chip microcomputer. The single-chip microcomputer has the characteristics of low power consumption, high performance, good reliability, and ease of production. Moreover, the single-chip microcomputer is more convenient, simple, and flexible in step control of temperature, which can improve the technical indicators of the controlled temperature, thus greatly improving the reliability of the product. In the design process, firstly, the hardware design is carried out. Secondly, the software design is carried out. And finally, comprehensive debugging is carried out to realize the constant temperature intelligent control of water temperature.

Технология получения топливного газа для нефтеперерабатывающей промышленности

Reducing energy costs for production and reducing air pollution is one of the key tasks today. The main sources of atmospheric air pollution at oil refineries are: tubular heating furnaces - 50%; reactors of technological installations - 12%; flares - 29% and bitumen installations - 9%. Therefore, the development and implementation of methods to reduce harmful emissions and increase energy efficiency during fuel combustion is one of the main environmental objectives. In the process of oil refining, a large number of gas components of different potentials, pressures and homogeneity of the medium are formed. The forming gases are usually sent to the torch as a recyclable product, and the lack of energy resources is compensated by the use of liquid fuel or natural gas. Consequently, the task of better consumption of hydrocarbon gas is being formed with the possibility of reducing the consumption of liquid fuel and natural gas, i.e. increasing the energy efficiency of production, which leads to a reduction in harmful emissions into the atmosphere. To achieve these goals in the oil refining industry, on the example of LUKOIL-Volgogradneftepererabotka LLC, a plant for producing composite fuel gas for oil refining furnaces was developed and a new composite fuel gas based on hydrogen-containing and hydrocarbon gases of its own production was obtained. The composition of the composite fuel gas includes a "blow-off" hydrogen-containing gas, previously burned on a flare.

Development of technology for the production of heat-insulating materials for use in metallurgy and mechanical engineering

The article considers the tasks of metallurgical, machine-building, and foundry enterprises of Ukraine regarding heat saving in these industries during the war and post-war periods and in the future. It is shown that the possibilities of developing heat and energy saving in metallurgy and machine building through the widespread use of effective heat-insulating materials made of multisilica fibre have not been fully realised in practice. A promising area of application of heat-insulating products is the construction, reconstruction and modernisation of existing metallurgical units in blast furnace, steelmaking and rolling sections. The technology for the production of modern heat-insulating materials made of multisilica fibre, which are efficient at temperatures up to 1600 °C, sometimes even higher, has been developed and put into practice. Possibilities of changing the operating temperature of products made of multisilica materials (cotton wool, felt, plates, felt, cardboard, etc.) by varying the content of aluminium, chromium, zirconium compounds in the charge for smelting multisilica materials are shown. Specific technical solutions to save energy are proposed, which allow reducing the cost of heating furnaces by ~ (40...45) % by using thermal insulation made of multisilica fibre. The experience of the SINTIZ LLC plant regarding the measures taken to modernise the SKB 6098 ore-thermal furnace is presented. As a result of the improvement of the furnace control system, electricity consumption decreased by ~ (5...15) %. The direction of further modernisation of multisilica fibre production is to combine separate local process control systems into a single closed automated control system for the production of this product. Research and development activities aimed at improving the technology for the production of heat-insulating materials and products based on the use of natural raw materials are also relevant.

Numerical simulation and optimization of steel tube billet heating process in rotary hearth furnace using computational fluid dynamics

Billet reheating is an important part of the steel production process. Since the production process will adopt different tube billet arrangement strategies, and the condition of the furnace hearth will also change due to long-term operation and accumulation of iron oxide scales, these factors will inevitably affect heating efficiency and temperature distribution uniformity of the tube billet, thereby affecting the quality of the final product. In this study, a physical and mathematical model was established for a 48 m diameter rotary hearth furnace of the seamless steel pipe production-line and typical 300 mm diameter tube billets of different lengths. Commercial FLUENT code was used to carry out CFD numerical simulation research on the influence of the aforementioned factors. Optimizing and adjusting strategies under different arrangement strategies were proposed, and the influence of furnace hearth condition change on heating effect was studied. The methods and simulation approach of this paper also have guidance for the billet heating control in similar continuous heating furnaces.

Сравнительная оценка энергетической и экономической эффективности парокомпрессионных тепловых насосов при модернизации крупного химического и нефтеперерабатывающего производства. Часть 1

The question of the feasibility of increasing the energy efficiency of large chemical and oil refining industries by replacing furnace heaters of process heat carriers and raw materials with vapor compression heat pumps is considered. An analysis of the relationship between the technical configuration of vaporcompression heat pumps, the operating parameters of their operation (determining the value of the energy conversion coefficient) and the ratio of the cost of various energy carriers is carried out. The presented results of a comparative analysis of the energy efficiency of various options for replacing a furnace with a vapor compression heat pump reflect the decisive influence of the technical level and design configuration of a vapor compression heat pump on the choice of the preferred upgrade option. However, a significant difference in commercial energy prices significantly changes the preferred ranking of these options.

Microhardness and Microstructure of In-Situ Formed Fe-50%TiC Composites by Different Heating Methods

The aim of this study is to fabricate in-situ TiC particle reinforced Fe matrix composites via volume combustion synthesis (VCS) through heating by two different sources. One group of reactant pellets was ignited by heating in an induction furnace (IF). The other group was ignited via heating by using a tungsten inert gas (TIG) torch. Thus, the differences in the microhardness and microstructure of the obtained composites could be compared. Fe, C and Ti elemental powders were used to obtain composites that contained 50 vol. % TiC in the Fe matrix. In the repeated experiments, the ignition temperatures of the IF pellets were found to be in 1164-1184 oC range. The formation of composites was verified by X-ray diffraction (XRD) analyses, where it was seen that the products were composed of TiC and Fe with trace impurity phase. Scanning electron microscope (SEM) examinations showed that the in-situ formed TiC particles were regularly distributed in matrix in both series. The TiC particles obtained by TIG heating were about 5 times larger than the particles obtained by induction heating. Microhardness values of the samples were higher in IF series as compared to TIG series. It was shown that 50 vol. % TiC particle reinforced Fe matrix composites could be obtained by both heating methods. TIG was found to be a much practical method, when compared to conducting VCS in a furnace.

Determination of Zinc, Copper, Iron, Nickel, Chromium, Cadmium and Lead in Milk Samples by Flame and Electrothermal Atomic Absorption Spectrometers

Milk samples consumed in the World, contain mostly important nutrients as well as toxic elements. Quality control is necessary in the production and processing of milk samples. Also, transportation and storage conditions have effects on the composition of samples. In this study, the concentrations of zinc, iron, chromium, nickel, copper, cadmium and lead in fourteen different brands of milk samples (pasteurized and long life) purchased from markets of Turkey in Ankara were determined and evaluated by using flame and electrothermal atomic absorption spectrometers (FAAS, ETAAS). Graphite furnace heating program for Cd and Pb determinations in samples was optimized in the absence or presence of nickel (Ni) matrix modifier. The limits of detection (LOD) for Cd and Pb determined by electrothermal atomic absorption spectrometry (ETAAS) in the presence of Ni matrix modifier were 1.2 and 1.5 µg L-1, respectively. The LODs of Cu, Fe, Zn, Cr and Ni determined by flame atomic absorption spectrometry were 18.4, 71.2, 20.8, 2.1 and 2.3 µg L-1, respectively. The mean concentrations and standard deviations (±s) of Zn, Ni, Cu, Cr, Fe, Cd and Pb were 1.7 ± 0.4 mg kg-1, 0.24 ± 0.08 mg kg-1, 0.8 ± 0.2 mg kg-1, 0.8 ± 0.6 mg kg-1, 1.9 ± 0.6 mg kg-1, 46 ±5 µg kg-1 and 28 ± 3 µg kg-1, respectively found in fourteen different milk samples. The contents of elements found in samples were compared with permissible limits recommended in the health criteria by the World Health Organization (WHO) and literature values. It was concluded that the tools and materials used in milk production were not caused to heavy metal contamination. The metal concentrations in the milk samples were within the limits of the maximum permissible metal values given by WHO/FAO, the other regulations and the Turkish Food Codex.

An integrated data-driven surrogate model and thermofluid network-based model of a 620 MWe utility-scale boiler

An integrated data-driven surrogate model and one-dimensional (1-D) process model of a 620 [ MWe] utility scale boiler is presented. A robust and computationally inexpensive computational fluid dynamic (CFD) model of the utility boiler was utilized to generate the solution dataset for surrogate model training and testing. Both a standard multi-layer perceptron (MLP) and mixture density network (MDN) machine learning architectures are compared for use as a surrogate model to predict the furnace heat loads and the flue gas inlet conditions to the convective pass. A hyperparameter search was performed to find the best MLP and MDN architecture. The MDN was selected for surrogate model integration since it showed comparable accuracy and provides the ability to predict the associated uncertainties. Validation of the integrated model against plant data was performed for a wide range of loads, and critical results were predicted within 5–8% of the measured results. The validated model was subsequently used to investigate the effects of using a poor-quality fuel for the 100% maximum continuous rating load case. The uncertainties predicted by the surrogate model were propagated through the integrated model using the Monte Carlo technique, adding valuable insight into the operational limits of the power plant and the uncertainties associated with it.

Контроль закоксованности змеевика трубчaтых нaгревaтельных печей в производстве водородa пaровой конверсией нa основе генетических aлгоритмов

Контроль закоксованности змеевика трубчaтых нaгревaтельных печей в производстве водородa пaровой конверсией нa основе генетических aлгоритмов

Application of Heat Treatment to Aluminum Alloy Wires and Comparison of Full Alloy AAAC Conductor Manufactured with These Wires and Conventional ACSR Stranded Conductors

Conventional ACSR conductors are formed by stranding aluminum wires over a steel core. The steel core does not contribute to current carrying and is used only for carrying purposes. The steel core has a great role in the shedding of the line weight. With the increase in line weight, longer poles are used at shorter distances, but it cannot be abandoned because it undertakes the transport task. Nowadays, the search for alternatives to the ACSR conventional conductor has accelerated. One of these alternatives is AAAC (Full aluminum alloy conductors). The wires in AAAC are hardened with special alloy production and eliminate the need for a steel core as a carrier in the center. While producing the aluminum overhead line conductor, after the aluminum ingots are melted in the melting furnaces and taken to the resting furnaces, after the addition of alloy elements such as Si, Mg in certain proportions, it is solidified by pouring it into a copper mold through refractory runners, and after the rolling process, 9.5 mm or 12 mm Aluminum Alloy rod (wire rod) semi-finished products are produced. While producing wire in the diameter determined in the standards for the overhead line conductor to be produced, 9.5 mm or 12 mm Aluminum rod (wire rod) is thinned with a certain reduction ratio in the semi-finished drawing process, and aluminum wire of the desired diameter is obtained. In the drawing process, the rod is rolled with a reduction ratio suitable for the machine and the final product to be produced. The wires produced are brought together with the step ratio in the standards to form a conductor. In order to gain the mechanical and electrical properties of the produced aluminum alloy wire, heat is applied at a certain time and temperature in heat treatment furnaces. Considering the heat treatment time and degree applied in this study, the properties before and after the heat treatment will be compared and the effect of the heat treatment process on the wire will be shown with experimental studies. Mechanical and electrical tests of AAAC 774 AL7 conductor made of alloy wires and ACSR Pheasant conductors made of aluminum wires knitted on steel cores will be carried out and the two conductors will be compared considering some parameters in line selection.

Dual reforming of model biogas for syngas production on Ni/γ-Al2O3 and Ni-C/ZSM-5 cordierite monolith catalysts

This work attempts to convert the model biogas on Ni/γ-Al2O3 and Ni-C/ZSM-5 into syngas using a dual-bed catalytic monolith reactor. The monolith is wash-coated with alumina and ZSM-5, respectively, followed by Ni and glucose-assisted Ni (Ni-C) loading using the wet impregnation technique. These two monoliths are loaded in an Inconel reactor and placed in a two-zone heating furnace. In dual reforming, either Ni/γ-Al2O3 or Ni-C/ZSM-5 monolith is used for dry reforming, and then Ni/γ-Al2O3 is used for steam reforming. A distance of ∼ 10 cm is maintained between these two monoliths. The exhaust gases from the first monolith are combined with steam before passing to the second monolith. The biogas reforming is carried out for a feed ratio (CH4:CO2) 1.5, GHSV of 1440 h−1 and 2880 h−1, at 800℃ and 1 atm pressure. The steam to CH4 ratio (S/C) is optimized to maximize the conversions (greater than80 %) of both CH4 and CO2. It was observed that the CH4 conversions increase with an increased S/C ratio due to the steam reforming in the second monolith. The TGA results show 7.6 % carbon formation on Ni-C/ZSM-5 and 35 % on Ni/γ-Al2O3 in dry reforming on the first monolith bed.

Study on the Behavior Mechanism of K and Na during the Synthesis of VN Alloy

In this paper, the sources of K and Na in vanadium-nitrogen (VN) alloys and their effects on the furnace structure were studied. The results show that K and Na are mainly present as counter-ions of decavanadate and dodecanadate in ammonium polyvanadate (APV) and vanadium trioxide (V2O3). In the production process of VN, the concentration of K in the scab produced in the kiln is 25 times higher than that of the vanadium raw material, the concentration of Na is 15 times higher than that of the raw material, and the degree of enrichment of K is stronger than that of Na. Additionally, in the VN products, K and Na are mainly distributed uniformly in the form of KCN and NaCN. The results also found that the K and Na vapors during the production of VN promoted the formation of VN. However, K, Na steam, KCN, NaCN, K2CO3, Na2CO3 and other potassium-sodium high-temperature corrosive substances cause strong corrosion of the furnace lining, graphite sagger, push plate, and heating elements. Therefore, in the process of synthesizing VN, the raw materials of K and Na content of impurity elements must be reasonably controlled. The results not only analyzed the source of K and Na, but also analyzed the characteristics of their enrichment and the influence on the equipment.

Development of a Raman spectroscopy system for in situ monitoring of microwave‐assisted inorganic transformations

AbstractMicrowave heating methods offer unique advantages in preparations of inorganic solids due to the high heating rates, potentially selective heating, and time/energy reductions. Understanding of these enhancements as well as involved mechanisms is poor due to the lack of available and easily applicable in situ monitoring methods, particularly for samples in the solid state. Existing in situ studies typically rely on access to beamline facilities as well as custom‐built microwave systems, which is in the best case inconvenient and in the worst case not achievable. In situ Raman spectroscopy is an ideal technique as it provides rapid and unambiguous phase identification by a noncontact method. Further, the instrument components are simple and compact, facilitating use in the typical synthetic laboratory. Only a few reports on using Raman spectroscopy for in situ measurements during microwave heating exist, and they all utilize specialized custom reactor setups. In this work, a new Raman measurement system designed to observe inorganic transformations in situ that is readily deployable in a standard, commercially available laboratory scale microwave reactor is described. As a simple demonstration, the anatase‐to‐rutile phase transition in TiO2 is monitored under both microwave and conventional furnace heating. The excellent time resolution achieved demonstrates the utility of the system in understanding microwave‐assisted methods for the preparation of inorganic compounds. The simplicity will encourage integration by the non‐specialist to understand microwave heating for synthetic preparations and promote wider application of the technique.

Heat Exchange between the Refractory Brickwork and the Metal in a Heating Furnace

Heat Exchange between the Refractory Brickwork and the Metal in a Heating Furnace

Vacuum-arc technology and equipment for cleaning and surface treatment of metal products operating under load

The material of the product should be considered as an integral concept that combines the substance, the technology of its production, design, technology of its manufacture and processing. The durability of products depends not only on the properties of the material, determined by the manufacturing technology and volumetric hardening, but also to a large extent on the properties of the surface. Its role in ensuring the performance properties of products is constantly increasing, which, along with the widespread use of traditional methods of chemical-thermal treatment, has contributed to the emergence and development of a new direction - surface engineering by methods of energy and physico-chemical effects. The high rate of high-frequency heating (hundreds of degrees per second) causes a shift in phase transformations to higher temperatures. Therefore, the high-frequency quenching temperature should be higher than the quenching temperature of ordinary furnace heating, and the higher the higher the heating rate. The current density across the section of the part is uneven, on the surface it is much higher than in the core. The main amount of heat is released in a thin surface layer. The depth of current penetration into the metal depends on the properties of the heated metal and is inversely proportional to the square root of the current frequency. The higher the current frequency, the thinner the resulting hardened layer. A reliable method of hardening the surface layer can give comparable results only if the quality of the surface is stable, including its cleaning. The surface condition of the part (tool) depends not only on the structure of the base material and all the conditions for its manufacture, but especially on the last operation of its production or processing. Research is being conducted, among other things, within the framework of the AP14869891 project “Increasing the operational life of heavy-loaded railway transport parts using innovative plasma technology”.

Heat Exchanger 5 Leak Analysis in PPSDM Migas

PPSDM Migas has an oil refinery with a capacity of 600 m3 per day where the crude oil produced will produce various products, such as pertasol CA, pertasol CB, pertasol CC, naphtha, diesel, and residue. One of the operating units used in this production process is a heat exchanger which aims to minimize the use of fuel in the furnace heating process. Of the five heat exchangers in the field, one of the heat exchangers was damaged, namely HE-05. Therefore, an analysis of the causes of damage to HE-05 was carried out with research methods in the form of field studies and literature studies, such as data collection on operating conditions in the Distributed Control System (DCS) and directly in the field using the Piping & Instrumentation Diagram (P&ID) so that it can calculate overall mechanical energy balance. Based on the results of the analysis, it can be concluded that the water content in crude oil exceeds the threshold (< 0.7%) of 5.5%. High water content will affect the steam fraction of crude oil which results in an increase in operating pressure. Then, the safety valve on the stabilizer did not work so that the gasket of the HE-5 was unable to withstand the high pressure in this incident. In addition, inaccurate pressure and temperature sensor readings cause operator delays in dealing with these incidents.   Keywords: Crude oil, heat exchanger, water content

Prospects of using mineral material for thermal insulation of sandwich pipes of chimneys

The problem of an increased level of fire danger in the residential sector among private houses and at the administrative and public buildings can be solved by reducing the flammability of both the entire structure and individual components of the building structure. In this paper, the possibility of using a magnesium-containing mineral to protect the chimneys of the sandwich pipe structure from excessive heating and to increase the level of fire safety during the organization of furnace heating is considered. Based on the results of studies using, a positive conclusion was made about the prospects of using the studied material as a filler with or sandwich pipes. The reduction of overheating of the roof elements in this case will occur due to the individual physico-chemical properties of the filler. This will reduce the number of chemical gorenje inhibitors that have a negative impact on the environment and people, to protect the wooden elements of the roof structure. Ill. 5. Ref. 18. Tab. 1.

Application of Optimizing Slab Corner Shapes to Reduce Edge Seam Defect on Heavy Plates

The edge seam defect is a common defect in hot rolling heavy plates. It can be improved by optimizing the corner shapes of slabs. Based on a numerical analysis of the effects of the slab corner shape on the temperature distribution after the slab’s exit from the heating furnace, three rolling methods are proposed for controlling the two-chamfered slab corner shape. The stress and deformation of the corner of the slab during the two-chamfered rolling process are investigated using a numerical simulation. The results show that a two-chamfered shape slab has the smallest temperature drop during the cooling process, and the slab corner can maintain higher temperature and uniformity, which is beneficial for controlling the deformation during the rolling process. Among the three kinds of two-chamfered rolling methods, frontal rolling using a two-roller has the smallest rolling force and rolling resistance to the casting machine, followed by horizontal rolling and then vertical rolling, which has the largest. The favorable slab corner in a two-chamfered shape can be obtained by frontal rolling using a two-roller. Industrial trials confirm that an edge seam defect rate of less than 5% in heavy plates can be achieved under the condition of a large broadside ratio.

Study on Purification Technology of Silicon Carbide Crystal Growth Powder.

Silicon carbide (SiC) is a wide-bandgap (WBG) semiconductor material, and its preparation process has strict requirements on the purity of raw materials. A self-developed medium-frequency induction heating furnace was used to carry out powder heat treatment and purification experiments on SiC powder to improve the purity of the powder. Samples with 3.5N purity were analyzed using XRD and GDMS characterization methods. It was found that under conditions of high-temperature (2200 °C) and long-time (50 h) processing, the impurity removal effect was quite good, but the powder loss was as high as 53.42%. The powder loss during the low-temperature (less than 2050 °C) and short-time process was less than 1.5%, but the purification effect was not substantial. After a prolonged processing time, the purification effect of low-temperature heat treatment conditions was improved, but the powder loss was also increased to 30%. In contrast, segmented purification processing at a low temperature in the early stage and a high temperature in the later stage achieved a good purification effect. On the premise of maintaining the utilization rate of raw materials, a 5N-purity SiC source was successfully prepared. The test results show that the contents of free Si, free C and free oxygen impurities were reduced to less than 0.01%, and the contents of Al, B, Fe, Mg, Na, Ti and other impurities were less than 1.15 ppm, which is close to the ppb level.