14th May 2018
Within the frame of their long-term development strategy aiming at domestic steel supply for growing India, the country’s state-owned Steel Authority of India, Ltd. (SAIL) awarded to Paul Wurth and Larsen & Toubro an order for the construction of a brand new blast furnace ironmaking plant for additional 2.8 million tons of hot metal capacity, in summer 2010. At Bhilai Steel Plant in the State of Chhattisgarh, where the existing BF plant consists of seven mid-size furnaces of Soviet design (built in the 1950-1980ies) the new unit was to become Blast Furnace No. 8. It has been commissioned in February 2018.
As per the contract with the customer, the project was executed on EPC basis by a consortium of Paul Wurth Italia, Paul Wurth India and the industrial construction company Larsen & Toubro of India. The Paul Wurth group used its worldwide setup to ensure all necessary engineering, the imported and local supply of technology and plant as well as adequate site supervision and customer support services.
A particular challenge of this project was to arrange all the required plant units within the allocated area for this brownfield installation. In particular, the layouts of the main charging conveyor, of the racks for utilities pipes and cables and of the railway tracks had to be finalized with unconventional solutions. This was important to ensure the maintainability and accessibility of the surrounding areas during construction and for the future operations of the plant.
A full range of proprietary Paul Wurth technologies has been included in this project: copper and cast iron staves, a 2H Bell Less Top® charging system with pressure equalizing valves and bleeders, cardan-type tuyere stocks, a hot stoves plant of 3 internal combustion chamber stoves with waste gas heat recovery and process valves of Paul Wurth design, pulverized coal injection based on dense-phase conveying with 3 injection hoppers and 70 t/h capacity, INBA® slag granulation with cooling tower, a top gas cleaning plant with axial cyclone, annular gap scrubber and downstream energy recovery turbine (TRT). The flat cast floor is equipped with TMT’s* hydraulic tapping machinery and monitoring devices for hot metal level measuring system inside torpedo car, altogether allowing maximum mechanized casthouse operations. A fix, multiple radar profilemeter and “wall-flow” in-burden probes, both also by TMT, found their first installation in this blast furnace. Finally, an extensive set of process models has been provided with Paul Wurth’s BFXpert® Level 2 automation system to facilitate timely and accurate monitoring and control of the complex plant operation.
Besides the recovery of hot stoves waste gas heat and the BF top gas’ potential energy, special attention to energy savings has been given also in other areas: for instance, frequency modulated (VVVF) drives have been applied to major electricity consumers with variable duty, such as the fans for cast house de-dusting and hot blast stoves.
BF8 at Bhilai is the largest blast furnace put in operation by Paul Wurth in India so far. It has an inner volume of 4,060 m3, a hearth diameter of 13.4 meters, 4 tapholes and 36 tuyeres. The nominal daily production is 8,030 tons of hot metal. At the current time, we observe the plant smoothly ramping up its production.
*TMT Tapping-Measuring-Technology is a joint company of Dango & Dienenthal and Paul Wurth.