Optimisation study of ironmaking using biomass

Helle, Hannu; Helle, Mikko; Pettersson, Frank; Saxén, Henrik

doi:10.1179/030192309x12506804200582

Cited by 16 publications

(12 citation statements)

References 8 publications

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“…This is in perfect agreement with the observations presented in Fig. 3 and the results of Helle et al 12,13) where a partial conversion of the biomass with a pyrolysis temperature of about 250°C was found to be optimal. Thus, the local minima reported by Helle et al 12) with respect to the pyrolysis temperature have been efficiently avoided by the search.…”

Section: Resultssupporting

confidence: 82%

“…With the exception of the pyrolysis unit, all other unit processes are described by linear models. Helle et al 12,13) studied a similar system, but with one BF only, and analyzed how the price of biomass and emissions affected the optimal state of the system with respect to costs of liquid steel. Results from their study will also be used as a reference for the present investigation.…”

Section: Models Flows and Emissionsmentioning

confidence: 99%

“…The last two terms in the parentheses are credits for produced electricity and heat. While the optimization problem for a plant with one blast furnace can be rather easily solved by nonlinear programming, 12,13) the present considerably more complicated problem was tackled by a subdivision of the optimization task. Given an aim steel production rate and admissible regions for the operation of the unit processes, a master problem governed by an evolutionary algorithm using the concepts of differential evolution was solved, where the resources are given to the two blast furnaces.…”

Section: Objective Function and Overall Formulationmentioning

confidence: 99%

“…The master problem makes its decision on the basis of the solutions of sub-problems, where one blast furnace is optimized by nonlinear programming for a fixed hot metal production and under given constraints on the available raw materials. This approach was inspired by the increased complexity of the task as well as by the fact that the effect of local minima encountered in the 1-BF formulation 12,13) could prove detrimental for a purely gradient-based optimization.…”

Section: Objective Function and Overall Formulationmentioning

confidence: 99%

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Optimal Resource Allocation in Integrated Steelmaking with Biomass as Auxiliary Reductant in the Blast Furnace

2012

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An integrated steel plant with two blast furnaces with the option to use biomass to partially substitute fossil reductants was simulated. A thermodynamic blast furnace model was used, combined with simpler models of the other unit processes (sintermaking, cokemaking, basic oxygen furnace, hot stoves and power plant) and a nonlinear model of the biomass conversion with respect to the processing temperature. Given an aim steel production rate for the plant, the economics of the plant was optimized by minimizing the specific costs of liquid steel, considering costs of raw materials, energy and CO2 emissions. Limited supply of sinter and coke was optimally allocated to the two blast furnaces and the effects of restrictions in the biomass, oxygen and oil supply on the operating states were studied. An analysis was also undertaken to study how the production rate of the plant would affect the optimal state. The results demonstrate that a non-uniform distribution of the resources can be economically justified, in particular for cases where the blast furnaces operate under different constraints.

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Section: Resultssupporting

confidence: 82%

Section: Models Flows and Emissionsmentioning

confidence: 99%

Section: Objective Function and Overall Formulationmentioning

confidence: 99%

Section: Objective Function and Overall Formulationmentioning

confidence: 99%

See 2 more Smart Citations

Optimal Resource Allocation in Integrated Steelmaking with Biomass as Auxiliary Reductant in the Blast Furnace

2012

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“…(Helle et al, 2010;Helle et al, 2009;Gupta, 2003;Suopajärvi and Fabritius, 2012; . Helle et al (2010) and Helle et al (2009) simulated partial substitution of fossil reducing agents with biomass in the BF. They concluded that the biomass had to be pre-processed through pyrolysis, because the high oxygen content and low heating value of raw biomass would reduce the productivity of the BF.…”

Section: Biomass As Reducing Agent and Fuelmentioning

confidence: 99%

Improved Energy Efficiency and Fuel Substitution in the Iron and Steel Industry

Johansson¹

2014

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IPCC reported in its climate change report 2013 that the atmospheric concentrations of the greenhouse gases (GHG) carbon dioxide (CO2), methane, and nitrous oxide now have reached the highest levels in the past 800,000 years. CO2 concentration has increased by 40% since pre-industrial times and the primary source is fossil fuel combustion. It is vital to reduce anthropogenic emissions of GHGs in order to combat climate change. Industry accounts for 20% of global anthropogenic CO2 emissions and the iron and steel industry accounts for 30% of industrial emissions. The iron and steel industry is at date highly dependent on fossil fuels and electricity. Energy efficiency measures and substitution of fossil fuels with renewable energy would make an important contribution to the efforts to reduce emissions of GHGs. This thesis studies energy efficiency measures and fuel substitution in the iron and steel industry and focuses on recovery and utilisation of excess energy and substitution of fossil fuels with biomass. Energy systems analysis has been used to investigate how changes in the iron and steel industry’s energy system would affect the steel plant’s economy and global CO2 emissions. The thesis also studies energy management practices in the Swedish iron and steel industry with the focus on how energy managers think about why energy efficiency measures are implemented or why they are not implemented. In-depth interviews with energy managers at eleven Swedish steel plants were conducted to analyse energy management practices. In order to show some of the large untapped heat flows in industry, excess heat recovery potential in the industrial sector in Gävleborg County in Sweden was analysed. Under the assumptions made in this thesis, the recovery output would be more than three times higher if the excess heat is used in a district heating system than if electricity is generated. An economic evaluation was performed for three electricity generation technologies for the conversion of low-temperature industrial excess heat. The results show that electricity generation with organic Rankine cycles and phase change material engines could be profitable, but that thermoelectric generation of electricity from low-temperature industrial excess heat would not be profitable at the present stage of technology development. With regard to fossil fuels substituted with biomass, there are opportunities to substitute fossil coal with charcoal in the blast furnace and to substitute liquefied petroleum gas (LPG) with bio-syngas or bio synthetic natural gas (bio-SNG) as fuel in the steel industry’s reheating furnaces. However, in the energy market scenarios studied, substituting LPG with bio-SNG as fuel in reheating furnaces at the studied scrap-based steel plant would not be profitable without economic policy support. The development of the energy market is shown to play a vital role for the outcome of how different measures would affect global CO2 emissions. Results from the interviews show that Swedish steel companies regard improved...

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