Process simulation is an essential tool for the design, integration and optimization of production plants. The process simulation tools used in the petrochemical, chemical and pharmaceutical industries are rarely used in the iron & steel industry due to the lack of metallurgical models for core processes (e.g., blast furnaces) and missing data of material properties. Often, isolated models are designed for single processes, which are not suitable for global simulation and optimization of integrated steel plants.
The focus of project 3.4 is a global simulation of steelmaking based on various concepts and technologies. Furthermore, the development of the existing model library is focused.
Objectives and Motivation
- Research on new plant concepts to reduce CO2 emissions and efficient use of resources
- Assessment on the effect of alternative raw materials and variable process parameters on the production process
- Performance estimation of metallurgical aggregates and the interaction of plants in the integrated steel plant/minimill
- Further development of existing metallurgical models and validation with process data
In previous projects, a model library was created for the equation-oriented process simulation software gPROMS. The library considers the iron&steel producing value-chain, starting from raw materials to crude steel. Furthermore, the library contains models for metallurgical processes and contains routines for material property estimation and models for non-metallurgical aggregates, such as heat exchangers, burners, reformers, gas conditioning systems, etc.
In project 3.4, flowsheets of various steel production sites are implemented into gPROMS software. The operation of steel plants is simulated by varying process conditions and parameters. Thus, the comparison of simulation results with corresponding operating data will validate the accuracy and robustness of the models, while insufficient operating data can be identified. To further enhance the accuracy of models the library is modified. This includes the implementation of abstract process variables through statistical models (e.g., mechanical and metallurgical parameters of sinter and coke) as well as the deepening of metallurgical process models. In particular, the focus will be on the LD converter, electric arc furnace and secondary metallurgy units. Especially for these implementations, the transient characteristic of the processes should be considered for modelling. In addition, wastewater treatment and gas distribution of integrated steelworks will be implemented, since the appearance of higher hydrocarbons and trace elements is of great interest.
Results and Application
The challenge of present time is a reduced use of fossil raw materials and an increased use of recycle streams in integrated steel plants. Project 3.4 investigates specific savings in the consumption of fossil fuels and other raw materials, effects on product quality and the need to adjust operation conditions. Process optimization with respect to CO2 footprint, emission reduction or increased raw material flexibility can be estimated for the existing steel production sites. New plant concepts are investigated such as the operation of the blast furnace with increased oxygen content in hot blast or increased hydrogen feed rate, blast furnace gas recycling, the use of HBI, hydrogen based direct reduction or the electric arc furnace process route. Moreover, the potential of future technologies in the network of integrated steel plants is estimated.
The simulation results of the integrated steel plants can be used to support life cycle assessments. The input data required for life cycle assessment programs can directly be taken from process simulations.