Critical analysis of a steel wire rod plant Processes for Energy Optimization-A case study
Energy is needed in the wire rod plant processes for any value addition activity to develop the finished product. The increased energy costs and an uncertain steel markets have created the demand for a system in the steel plant, to utilizes the rolling process waste heat, or improve rolling process so that next further processing may be avoided for rolled product.. The process energy optimization is a tool to improve profitability, environment and productivity of an organization. In a wire rod plant processes, the aim of energy saving can be achieved by reduced resource consumption and by efficient use of plant installation like reheating furnace, mills and utility. A case study is used to illustrate the rolling processes energy optimization and to demonstrate its applicability.
Maintenance strategy for tilting table of rolling mill based on reliability considerations
Abstract Reliability centred maintenance (RCM) is a new strategic framework for ensuring that any asset continues to perform, as its users want it to perform. RCM is a process used to determine the maintenance requirement of any physical asset in its operating context. RCM process entails asking seven questions about each of the selected assets. It makes use of two documents namely, RCM information worksheet and RCM decision worksheet. RCM decision diagram integrates all the decision processes into a single strategic framework. RCM concept developed by US commercial airlines industry has been successfully implemented by Military, Navy, Nuclear power plants, electric power generation and distribution undertakings and several other sectors. These projects have been carried out in the United Kingdom, The Republic of Ireland, the United States, Hong Kong, Australia, Spain and Singapore. The fact that people has enthusiastically received RCM at all levels and has enabled users to achieve some remarkable successes in all of these countries, suggests that it can be universally employed. Literature review indicates that RCM approach is not conventionally applied in process industries in India. Presently, predictive maintenance (PDM) approach along with conventional preventive maintenance is used in continuous/process industries. This approach if implemented in totality will increase the production cost to a large degree and make the production uneconomical. Similarly breakdown maintenance (BDM) approach cannot be applied in such industries as each breakdown involves huge costs. RCM approach is a compromise between PDM and BDM approach for optimising the cost and ensuring the availability of machine. The RCM approach has been applied to the tilting table system of rolling mill for the research work reported in this paper. In the present study, preventive maintenance tasks suggested for power transmission subsystem, guiding and transportation subsystem and hydraulic subsystem in tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices.
Modelling of Thermometallurgical Process in A Runout Table, Part 1: A Bond Graph Approach
Abstract A bond graph model of thermometallurgical process in a moving continuum like the runout table cooling is developed in a two-part article. Detailed heat transfer process involving jet impingement, two-phase film boiling, and radiation is considered in these works. Scheil's additivity rule for incubation process and Johnson-MehlAvrami phase kinetics for transformation are used to model the process involving material transport and temperature variation. Two types of steel are considered to demonstrate the working of the model for decomposition of austenite to pearlite and the same to ferrite-pearlite. Part 1 is devoted to the creation and fusion of the thermal, incubation, and phase kinetics modules. Part 2 presents simulation and parametric studies.