Ways of Reducing Energy Costs in the Continuous Rolling of Sections

Zhuchkov, S. M.; Kulakov, L. V.; Lokhmatov, A. P.; Palamar, D. G.; Sheremet, Vitalii A.; Kekukh, A. V.; Babenko, M. A.; Spinyakov, V. K.

doi:10.1023/b:mell.0000037179.70404.9b

Cited by 4 publications

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“…Reheating semi-finished products in the furnace prior to rolling consumes fuel energy in the range of 1,30 -1,65 GJ/t finished product. Unit fuel consumption reduction by 9 -10 % can be realised by reducing the heating temperature by 100 °C [96]. However, this technology has an overall energy consumption increase impact.…”

Section: Steel Hot Rolling Milling Operations: Proper Reheating Temperaturementioning

confidence: 99%

Improving By-product Gas Utilisation in Steel Milling Operations

Mampuru

2019

SSRN Journal

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Iron and steel manufacturing are energy-intensive processes. Rising energy and operational costs have placed South African steel manufacturers under financial strain, while they struggle to remain afloat within an extremely competitive global market. Declining production and export figures, as well as increasing imports, have adversely affected the sustainability and profitability of the local market. It is, therefore, imperative for local manufacturers to implement operational change strategies without additional capital investment requirements in order to save energy and reduce costs.Hot-rolling processes of steel milling operations use reheating furnaces to elevate the temperature of the steel to a state of plastic deformation prior to rolling. The reheating furnaces combust fuel gases such as by-product gases or natural gas for thermal energy. They consume 70 % of the energy of the hot-rolling processes. By-product gases are combustible carriers of energy. Coke oven gas (COG) carries 18 % of the energy input of the coke production process. The energy content of COG was found to be competitive with natural gas and compatible for high-energy requirement applications, such as in reheating furnaces.The challenge arises in that the calorific value (CV) of COG fluctuates over time. These fluctuations prove problematic during the control of COG combustion processes as the air-fuel ratio needs to be adjusted accordingly. Furnace operators typically rely on a trial-and-error method for air-fuel ratio adjustments in response to the fluctuating calorific value of coke oven gas (CV of COG). This causes furnace temperature instabilities, energy inefficiencies and production losses. Additionally, COG has a high impurity content inherent from the coal. These impurities clog CV of COG analysing equipment.Several alternative tools are available to estimate the unavailable CV of COG; however, these tools do not account for the fluctuating nature of COG and only provide static estimated values.Based on these challenges, a need was identified to facilitate more stable operations of the furnace. The aim of this study entails the development of a new methodology to adjust the Improving by-product gas utilisation in steel milling operations ii air-fuel ratio according to the incoming CV of COG and the current furnace operating conditions. The historic behaviour of the furnace is used in the control strategy.To address the recurring events where CV of COG data is unavailable, a novel methodology is developed for a time-continuous estimation of CV of COG for stable process applications.A seven-step methodology was developed whereby an appropriate method can be selected for the determination of CV of COG, based on the available data and measuring equipment.Three methods are presented, with varying accuracy and consistency.Pilot studies were undertaken on a billet mill reheating furnace in order to validate the air-fuel ratio adjustment methodology. The results verified that the air-fuel adjustments were within 94 % -98 % accurate, res...

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Section: Steel Hot Rolling Milling Operations: Proper Reheating Temperaturementioning

confidence: 99%

Improving By-product Gas Utilisation in Steel Milling Operations

Mampuru

2019

SSRN Journal

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“…The heating operation should also ensure dissolution of the inclusions in the metal in the absence of excessive grain growth. A reduction of the heating temperature by 212 °F (100°C) decreases unit fuel consumption by 9% to 10% (Zhuchov et al, 2004). However, lowering the heating temperature will increase the rolling forces and moments, and hence increase the load on the electric drive motors, i.e.…”

Section: Hot Rollingmentioning

confidence: 99%

“…it will have the overall effect of increasing the mechanical and electrical loads on the main components of the mill, thereby increasing energy consumption and wear of the mill equipment. As a result, under certain conditions total unit energy consumption may not decrease with a decrease in heating temperature (even without allowance for the losses associated with electric power generation) (Zhuchov et al, 2004). The heating temperature should therefore be carefully considered using a systems approach.…”

Section: Hot Rollingmentioning

confidence: 99%

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Energy Efficiency Improvement and Cost Saving Opportunities for the U.S. Iron and Steel Industry An ENERGY STAR(R) Guide for Energy and Plant Managers

Worrell¹,

Blinde²,

Neelis³

et al. 2010

124

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Energy is an important cost factor in the U.S iron and steel industry. Energy efficiency improvement is an important way to reduce these costs and to increase predictable earnings, especially in times of high energy price volatility. There are a variety of opportunities available at individual plants in the U.S. iron and steel industry to reduce energy consumption in a cost-effective manner. This Energy Guide discusses energy efficiency practices and energy-efficient technologies that can be implemented at the component, process, facility, and organizational levels. A discussion of the structure, production trends, energy consumption, and greenhouse gas emissions of the iron and steel industry is provided along with a description of the major process technologies used within the industry. Next, a wide variety of energy efficiency measures are described. Many measure descriptions include expected savings in energy and energy-related costs, based on case study data from real-world applications in the steel and related industries worldwide. Typical measure payback periods and references to further information in the technical literature are also provided, when available. The information in this Energy Guide is intended to help energy and plant managers in the U.S. iron and steel industry reduce energy consumption and greenhouse gas emissions in a cost-effective manner while maintaining the quality of products manufactured. Further research on the economics of all measures-and on their applicability to different production practices-is needed to assess their cost effectiveness at individual plants.

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