Automation of Blast Furnaces at Tata Steel with NetBeans
The Automation Division of Tata Steel Ltd has developed a Level2 system Blast Furnace and implemented a H–Blast Furnace at Tata Steel Jamshedpur.
The application described below was first developed using plain Java Swing and was later moved to the NetBeans Platform, as evidenced by the screenshots below, because it offers modularity and better windowing features.
The Automation Division of Tata Steel Ltd has developed a Level2 system Blast Furnace and implemented a H–Blast Furnace at Tata Steel Jamshedpur. The Level2 system is in operation since 2008. The capacity of the H-Blast Furnace is of 2.8 MTPA with 3500 CU. MT of working volume.
A blast furnace is a counter current chemical reactor where semi-processed raw materials like sinter, ore and coke are charged (charging process) from the top of the furnace and hot blast air is blown (blowing process) in from the lower part of the furnace. The hot blast air reacts with the descending coke and produces blast furnace gas (CO, CO2) which progressively reduces the iron-oxide of the charged material and produces hot metal (liquid iron). The hot metal, along with the slag (the impurities) is collected in a pit at the bottom of the furnace called hearth from where it is drained out periodically (tapping process) and transferred to steel making shop to produce steel.
Blast Furnace Level2 system is a collection of mathematical & mass-energy balance models which, based on first principles, mathematical equations and numerical methods, simulate the blast furnace process in segments (charging, blowing, tapping) on real time basis. The models extract plant data like flow, temperature, pressure, distance, velocity etc from the field devices and convert them into trends using fundamental principles of physical laws . For example, a Level2 model uses the radar data that measures the filling rate of hot-metal in torpedo and converts the information to the occupancy of the hot metal in the hearth. It displays the liquid level of hearth to the cast–house operators. Another model uses the radar data that measures the depth of charging material from the furnace top and converts the information to show the layer-wise profiles of the charged materials at the furnace top. Another model predicts the direct and indirect reactions, the solution loss and other thermal and reaction parameters of the furnace using the information of charging, blowing and tapping processes.
The Level2 system helps operators to visualize the process of the blast furnace and in turn assists them in operation with better control facilities. Often the system is used in advisory mode which triggers alarms or guides the operators to take early corrective actions. It also assists the process owners to monitor the health and stability of the furnace.
- Burden Preparation
This model computes the optimal composition (by weight) of the burden using the available raw materials and achieving the target basicity and hot metal composition.
Fig 1.1 Burden Preparation Model
- Hearth-wear Model
This model computes the hearth lining profile using the hearth thermocouples. The computation is made using Finite Element methods.
Fig. 2.1 Hearthwear Model
- Burden Distribution Model
This model generates the radial distribution of burden layers determined from trajectory path of the discharged material. The model is useful for determining the distribution of the charging material at the throat level prior to its actual discharge to the furnace.
Fig. 3.1 Burden Distribution model
Fig. 3.2 Burden Distribution model
- Liquid Level Monitor
This model determines the levels of hot metal and slag in the hearth based on the computed hot metal and slag inflow using mass balance, Hot metal outflow using the radar level sensors for the torpedoes, slag outflows through the granulation plant torque measurement and hearth geometry.
Fig 4.1 Liquid Level Monitor
Fig 4.2 Liquid Level Monitor
Fig 4.3 Liquid Level Monitor
- Water Ingress Monitor
This model is used for early detection of leakage of water through tuyeres.
Fig 5.1 Water Ingress Monitor
Fig 5.2 Water Ingress Monitor
- Stock House Matrix Editor
The Stock House Matrix Editor is the facility to the operators to prepare the stock-house matrix. Here the old matrices can be reused, or a new matrix can be created.
Fig 6.1 Stock House Matrix Editor
- Heat Loss Monitor
This model computes segment-wise heat-losses from the furnace wall (Hearth, tuyeres, bosh, belly, shaft, throat etc.) using the cooling circuit water flow, inlet and outlet temperature of the water flows. It determines the fuel equivalence of the heat losses through wall. It is used to control the fuel rate during the shutdown time.
Fig 7.1 Heat Loss Monitor