Cupola Melting Research Articles

Experimental and industrial method of synthesis of optimal control of the temperature region of cupola melting

The object of research is the temperature regime of melting in a cupola. The synthesis of optimal control of such an object is associated with the presence of a problem consisting in the complexity of its mathematical description and the absence of procedures that allow one to obtain optimal control laws. These problems are due to the presence of links with a pure delay, non-additive random drift, and difficulties in controlling the process parameters, in particular, accurately determining the temperature profile along the horizons and the periphery of the working space of the cupola. The proposed conceptual solution for the synthesis of optimal temperature control allows the use of two levels of control: the level controller solves the problem of maintaining the constant height of the idle charge, and the problem of increasing the temperature of cast iron is solved by controlling the air supply to the tuyere box. It is shown that the problem of regulating the upper level of an idle charge can be solved by reducing the model of the regulation process to a typical form, followed by the use of the Pontryagin maximum principle. A procedure for the synthesis of optimal air flow control is proposed, which makes it possible to obtain the temperature regime control law on the basis of experimental industrial studies preceding the synthesis process. This takes into account the time delay between the impact on the object and its reaction, which makes it possible to predict the temperature value one step acharge, equal to the time interval during which the lower surface of the fuel charge reaches the upper surface of the level of the idle charge. A procedure for temperature profile control based on the use of D-optimal plans for selecting sensor installation points is proposed. Due to this, it becomes possible to determine the temperature profile of the cupola according to its horizons and the periphery of the working space of the cupola with maximum accuracy. The proposed synthesis method can be used in iron foundries equipped with cupolas, as it is a tool for studying a real production process, taking into account its specific conditions. This will allow developing or improving control systems for cupola melting, implementing different control modes: manual, automated or automatic

Estimation of Smelting Efficacy and Properties of Molten Metal in Cupola Melting

Estimation of Smelting Efficacy and Properties of Molten Metal in Cupola Melting

Foreword for Special Issue on Melting of Cast Iron, Properties of Molten Metal and Biocoke for Cupola Melting

Foreword for Special Issue on Melting of Cast Iron, Properties of Molten Metal and Biocoke for Cupola Melting

THE GEOMETRICAL PARAMETERS OF THE CUPOLA AND THE HEIGHT OF THE CHARGE COLUMN WHEN REPLACING COKE AND ANTHRACITE OR LEAN COALS

When replacing coke and anthracite coals lean in cupola melting to consider increasing the likelihood of cracking of coal due to its low thermal resistance. Technologically steady state smelting with anthracite and lean coal is provided by the work of the recommended ratio between the height of the cupola and its diameter and heating the blast in the recuperator “pipe in pipe”.

THE ANALYSIS OF THE FORCES ACTING ON A COKE PACKING OR COAL FUEL NOZZLE INTO SMALL DIAMETER SHAFT FURNACES (CUPOLA)

The article presents the analysis of the forces acting on a coke packing or coal fuel nozzle into the cupola by replacing coke with anthracite and lean coal. The obtained data allow estimating preliminarily in size and shape of burden pieces a probable forecast of cupola melting behavior. The conclusion is that by the transition to the marks of coals to increase the frictional force on the wall of charge, the charge itself must be carefully carve into minimum pieces, which reduces drastically the angle of the engagement and consequently the angle of internal friction coefficient increases as well as the pressure on the side wall of the shaft.

Application of Temperature Forecasting in Cupola Melting Process Based on BP Neural Network

In cupola melting process, the temperature of molten iron is an important indicator of the quality of cast iron. Its difficult to optimize the design because of the varicosity of influencing factors in cupola melting process. This article established a BP neural network model to forecast the temperature of molten iron in cupola melting process, thus use the genetic algorithm to optimize the model. Comparing the average errors of the temperature of molten iron before and after optimization, it indicated that the BP neural network model using genetic algorithm optimization forecasted the actual situation in cupola melting more accurately.

The Composition Forecasting Research for Cupola Melting Process

This paper summarizes components and phases involved in the cupola melting process, then brings out a composition forecasting model based on the minimum Gibbs energy principle and the equilibria calculation algorithms of multiphase and multicomponent. Besides, the relationship between the melting parameters and the composition of molten iron is set up by using BP neural network based on the idea of indirect constraints. Finally, the paper probes the feasibility of the composition forecasting model with two examples. The application result shows that the prediction with this method can achieve strong practicability and popularization value.

G080011 次世代バイオ固形燃料 : バイオコークスの熱間特性

With commercial nuclear power plants from 1966 still running and the price jump of coal coke in 2003, cupola melting systems has made the transition to electric furnaces with cheaper electricity rates at that time. But after the recent East Japan earthquake, the resulting increase in electricity rates, influenced by the tragedy, is dictating overseas relocation of these manufacturing companies and thereby threatening to ruin the condition of the domestic industry. Under these circumstances, there is an urgent need for manufacturing companies in this country to envision the next generation of alternative fuel sources by creating a system that utilizes bio-solid fuels instead of depending on fossil fuel resources. In this study, a new melting system with specific technical elements based on Bio-coke is proposed.

Spheroidal Graphite Iron with High Ductility at Cast State and Produced by Cupola Melting

This paper described an industrial scale experience of melting as-cast high-ductility nodular iron. We discussed the rationale of selection of chemical compositions and the practice of speroidising and inoculation processes. The experimental results show that nodular iron castings with consistent quality at cast state can be produced using cupola melting technique. The castings of two heavy truck components–brake shoes and brake plates produced meet the technical requirements set in China standard GB/T1348-2009.

Decrease of Boron in Cupola Melting Process

Decrease of Boron in Cupola Melting Process

Numerical Analysis of Reactions in a Cupola Melting Furnace

Composition variations of metal and slag in a cupola melting process were investigated by a reaction model for gas/liquid iron/coke and slag/liquid iron systems. A significant amount of alloy elements is lost due to the gas oxidation in furnace shaft. Carbon in metals is determined by gas oxidation and carbon pickup from coke in the shaft. Manganese and silicon are mainly lost by gas oxidation in shaft. Sulfur increases in shaft by pickup from coke but decreases in siphon by slag desulphurisation. There is no significant phosphorus change in shaft, but phosphorus increases in siphon. Oxides formed in shaft contribute 20% of total tapped slag, in which SiO2 contribute 40% of total SiO2 in the tapped slag.

Direct nodularizing from cupola iron

Cupola melting increases the sulphur content in the melt complicating the production of ductile iron sometimes with a desulphurization step. Nodularizing in a converter, for large productions, avoid the desuphurization process but is not practical for a foundry producing only a low percentage of ductile iron in its total production.After having tested different nodularizing processes the cored wire technology combined with in the mould inoculation appears to be the best solution for treating an iron with sulphur content of 0,07%. The mechanical properties of such ductile iron are excellent. Over 750 MPa in tensile strength and 12% elongation are obtained in as-cast condition. The pre-germs produced by the use of silicon carbide in the charge, the higher S content and the cored wire nodularization and in the mould inoculation provides massive and near instantaneous nucleation giving rounded graphite spheroids and uniform size that explain the result obtained.

Total Assessment Evaluation Of a Cupola-based to Electric Induction Furnace Replacement

This article highlights a very important aspect of a broader effort which addresses the post-implementation follow-up of a total assessment audit (TAA) performed at a mid-size Iowa foundry by the Iowa State University`s Center for Building Energy Research (ISUCBER). One of the major goals of a TAA is to analyze and document the impact of implementing energy conservation, waste minimization, and productivity enhancement opportunities at a facility. The main focus of this study is the replacement of a coke-fired cupola melting operation with one which utilizes electric induction furnaces (EIFs) instead. This work contrasts the cupola-based melting operating with the EIF-based operation. The comparison is made on the basis of production schedules, energy usage, and environmental considerations. A cost analysis based on energy utilization and labor cost differences is also presented. One of the major findings of this study was that the melting effectiveness of the EIF-based operation (i.e., the ability to provide the required heat to melt the charge components) is approximately 51 percent versus that of about 20 percent for the cupola. Therefore, the replacement project has not only led to a more environmentally-friendly approach but also to a more efficient and productive melting operation. In fact, despitemore » an increase in overall electricity consumption, the overall energy consumption decreased due to the elimination of coke. The annual cost savings reflected, which include energy and labor costs, are expected to be approximately $0.0198 per pound of iron melted. This corresponds to an overall cost reduction of about 27 percent.« less

キュポラ溶解技術の変遷と最近の進歩

キュポラ溶解技術の変遷と最近の進歩

The Variation of Hydrogen, Oxygen and Nitrogen Levels in Cast Iron with Varying Blast-air Moisture

The effects of blast moisture on the gas content—hydrogen, oxygen and nitrogen—of molten iron derived from cupola melting have been studied, the dissolved oxygen content being measured by oxygen probes. It has been found that the hydrogen and oxygen contents of molten iron increase with rising levels of air moisture, although the nitrogen content remains almost the same. The rise in oxygen content is mainly the result of an increase in combined oxygen (oxide inclusions), the level of dissolved oxygen remaining almost unchanged.

Estimation of Cokebed Height during Cupola Melting Operation

Estimation of Cokebed Height during Cupola Melting Operation

Devitrification hardening of cupola slag glass with CaO and SiO 2 additions

Slag from the cupola melting of pig and scrap iron was melted, air quenched into a glass and then devitrified forming an abrasion resistant fibrous microstructure. This crystallization behavior was further investigated by altering the composition of the major constituents of the slag, namely, CaO and SiO 2. The resulting structural and microstructural changes were measured with XRD, SEM, optical microscopy and DTA techniques. The first crystalline phase formed at ∼900°C was Mg-wollastonite, with a microstructure of finely interwined fibrous growth. Diopside was detected at ∼950°C, with a comparatively coarse fibrous microstructure. CaO addition enhanced the formation of Mg-wollastonite while SiO 2 addition resulted in enhanced diopside formation. After heat-treating the samples to 1000°C and holding for 60 min, the CaO-rich samples, having formed predominantly dense fibrous Mg-wollastonite, showed a hardness of 903±40 on the Vickers scale, an increase of a factor of 2 over amorphous samples. The maximum hardness in silica-rich samples after a suitable heat treatment was 771±69 kg/mm 2.

Full-scale remediation of a grey iron foundry waste surface impoundment

A large grey iron foundry was facing remediation of a surface impoundment containing approximately 300,000 cubic yards of EP-Toxic sludge. The sludge was generated by the settling of wastewater solids from air emission control systems connected with cupola melting operations. Bench-scale treatability testing was used to evaluate various chemical treatment possibilities for rendering the sludge non-EP-Toxic. Several phosphate sources and different engineering options were evaluated for cost-effectiveness of full-scale remediation. The most economical option was to dredge the solids continuously as a slurry (while the impoundment remained in operation) with injection of phosphoric acid into the slurry pipeline. The treatment process was controlled by monitoring residual phosphate in the treated slurry. The remediation process was tested in a month-long field trial using full-scale equipment, and was followed by successful remediation during a 6-month period. A technical overview and performance data on the remediation process are presented.

Sewage Sludge Melting Process by Coke-Bed Furnace: System Development and Application

A sewage sludge melting process by coke - bed furnace, which is an application of cupola melting technology, was developed. The outline of the course of the development from the bench - scale experiment to the construction of a commercial plant is described. The process is a more sophisticated one which enables high volume reduction, stabilization and utilization of sewage sludge. The slag produced by the process has a volume reduction ratio of 1/9 to 1/40 compared with dewatered sludge, and potential to be utilized as road subbase material and concrete aggregate. The operational cost of the process is estimated to be comparable to that of the conventional ones.

Combustion in a Cold Blast Cupola

Abstract Cupola melting is primarily combustion/gasification of a coke bed containing a high inert of which some fraction melts continuously. The data base on such systems is sparse. So far base line experiments have been carried out without melting. In the present study, detailed experimental investigations were carried out on a 200 mm diameter cupola with and without melting of metal. The study of the distribution of temperature and the concentrations of the products of combustion at different points in the cupola in the two cases (i.e., with and without melting of metal) has revealed that the combustion (oxidation) as well as gasification (reduction) reactions are intensified right from the luyere level in the combustion zone. when melting of metal occurs on a thick coke bed and the superheated molten metal trickles down the bed. The carbon precipithick tation reaction is catalyzed by the solid cast-iron charge at elevated temperature in the melting zone and above it. The zone of negligible oxygen concentration (ZNO2) and the zone of maximum carbon dioxide (ZMCO2) and the zone of maximum temperature (ZMT) appear at lower heights, when the metal is melted and also the ZMCO2 and ZMT do not coincide as in the case of combustion of coke alone. The temperatures of gases at all the points in the regions above the melting zone and also in the ZMT are reduced. The temperature of gases at all the points in the regions below the melting zone are found to be higher. The melting rate and the molten metal temperature at the spout are observed to be a direct linear function of the combustion efficiency ratio (πc). the relative carbon saturation (RCS), and the temperature of the gases (Tg) at the periphery within the melting zone, just above the initial coke-bed height.