Cupola modeling project nearing phase II.

Initiated in May 1989, the first phase of a two-part AFS research project aimed at developing a user-friendly computer model of the cupola melting furnace is scheduled for completion July 19,1990. The model permits real-time process control and off-line process optimization. Phase II of the project will begin immediately and the entire project is expected to continue three years.

The model describes the heat transfer, fluid flow and chemical processes taking place within the cupola. According to Daniel Twarog, AFS director of research, it will provide a more comprehensive description of cupola behavior than can be obtained from the empirical correlations that have been previously attempted.

When completed, the program is expected to yield several significant benefits for foundries that utilize the cupola as their primary melter. Among these are:

* increased energy efficiency, leading to reduced fuel consumption, lower oxygen requirements and increased iron melting rates;

* reduction in the oxidative loss of alloy elements, particularly carbon, silicon and manganese;

* reduction in scrapped castings due to more uniform and predictable iron composition.

Cost savings for foundries utilizing the cupola model are estimated to approach $320 million annually.

The program is cooperatively supported by groups from the Massachusetts Institute of Technology, University of Michigan, General Motors Corp and Modern Equipment Co. Funding has been provided by AFS and 17 foundries and supplier companies. In addition, contributions in-kind have been accepted from General Motors, Modern Equipment and Deere and Co. Program direction is being conducted by a nine member industry advisory group. The group evaluates developments on a quarterly basis and receives monthly progress reports. Quarterly reports are also provided to all participating organizations for their comments.

In the first phase of the project, a one-dimensional steady-state model is being created based on the best available data. The model is extensively tested against performed and documented cupola operational data. This provides insight into the model's features that will require further investigation, according to Twarog.

During Phase II, a two-dimensional transient model is planned. The model will be augmented by experimental laboratory work and operating cupolas to provide mechanical insight and data needed to improve the accuracy of the model.

Phase I

Despite a lack of anticipated input from existing blast furnace models, the first phase of the research project is expected to be completed by mid-July. This model is expected to provide the mass flow rates, compositions and temperatures of iron, slag and off-gas, as well as temperature and composition profiles within the cupola. Pressure drop calculations will also provide slag height predictions.

Accurate and detailed sets of cupola data were furnished for use in testing the accuracy of the models being developed. This included a temperature profile inside the cupola. A cupola modeling program, developed by Modern Equipment Co and Norman Lillybeck of Deere and Co, was also provided. This program contains useful algorithms based on theoretical correlations of extensive cupola data.

In addition to work directly related to the modeling, an appraisal was conducted on available sensors that could provide input for on-line control. A brief examination into potential applications for expert systems technology was also performed. Further expert system work will await the completion of the steady-state model.

While much of the Phase I work was tied to existing blast furnace models, efforts to use this data was abandoned. Despite outward similarities of the cupola and blast furnace, it was found that the processes differ significantly. This rendered much of the initial work inapplicable. These findings will generate additional experimental programs during Phase II for the final cupola model.

Phase II

As planned, Phase II of the program will develop more complex and accurate cupola models. The simpler models generated during the first phase will be retained and upgraded to augment those developed in Phase II. This will allow foundries of various capacities and technical expertise to utilize the various models.

The key objectives of Phase II will include the following:

* develop a fully tested and refined one-dimensional model where transport phenomena and thermochemical aspects of the problem are fully integrated and tested against experimental measurements;

* extend this model to represent the transient behavior (in one dimension) to describe system response to varying operating conditions;

* develop a two-dimensional representation of this metal with full integration of the transport phenomena and thermochemical aspects of the cupola process.

When completed, the model will predict the following for a given set of input parameters:

* spatially non-uniform gas flow distribution;

* gas composition (CO[.sub.2],CO,N[.sub.2],H[.sub.2] and H 20);

* composition and temperature of three liquid streams, namely the steel, iron and slag streams;

* transient response to variations in the operating conditions.

According to Twarog, "By the end of Phase II, three useful cupola computer models will be available to the industry. Because we believe there will be a strong industry demand for these models, our intention is to provide an ongoing program that will continue upgrading the cupola models beyond the end of program."

(Figures omitted)