Energy recovery from high temperature slags

Barati, Mansoor; Esfahani, Shaghayegh; Utigard, T. A.

doi:10.1016/j.energy.2011.07.007

Cited by 266 publications

(172 citation statements)

References 22 publications

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“…Slag is a large source of excess energy in the iron and steel industry. The slag is tapped at temperatures of up to 1650°C and the heat energy is generally not recovered (Barati et al, 2011). Energy recovery from high-temperature slag in the iron and steel industry has been studied by e.g.…”

Section: Recovery Of Industrial Excess Heatmentioning

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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Section: Recovery Of Industrial Excess Heatmentioning

confidence: 99%

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

Johansson¹

2014

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“…With the acceleration of global warming nowadays, energy saving and CO 2 emission reduction in the steel industry is attracting more and more attention, although the energy efficiency has already been substantially improved by implementing extensive advanced technologies. According to the previous estimations [3,4], high temperature (1450-1550 °C) slags, carrying a substantial amount of high quality heat, represent the last potential source for energy reduction in the steel industry. In China, the steel industry's output of crude steel was more than 710 million tons in 2012 [5], and accordingly around 200 million tons of high temperature blast furnace slags (BF slags) and 70 million tons of steel slags were produced [6] and the total waste heat was more than 4.80 × 10 19 J, equivalent to 16 million tons of standard coal, whereas less than 2% of that was recovered, according to the estimation of Cai et al [7], so there is a great potential of waste heat recovery.…”

Section: Introductionmentioning

confidence: 99%

Multi-Stage Control of Waste Heat Recovery from High Temperature Slags Based on Time Temperature Transformation Curves

et al. 2014

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This paper presents a significant method and a basic idea of waste heat recovery from high temperature slags based on Time Temperature Transformation (TTT) curves. Three samples with a fixed CaO/SiO 2 ratio of 1.05 and different levels of Al 2 O 3 were designed and isothermal experiments were performed using a Single Hot Thermocouple Technique (SHTT). The TTT curves established through SHTT experiments described well the variation of slag properties during isothermal processes. In this study, we propose a multi-stage control method for waste heat recovery from high temperature slags, in which the whole temperature range from 1500 °C to 25 °C was divided into three regions, i.e., Liquid region, Crystallization region and Solid region, based on the TTT curves. Accordingly, we put forward an industrial prototype plant for the purpose of waste heat recovery and the potential of waste heat recovery was then calculated. The multi-stage control method provided not only a significant prototype, but also a basic idea to simultaneously extract high quality waste heat and obtain glassy phases on high temperature slags, which may fill the gap between slag properties and practical waste heat recovery processes.

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“…Barati et al (2011) evaluated these three technologies and found that, for both thermal and chemical energy recovery, a two-step process would yield a high efficiency with minimal technical risk. For thermoelectric power generation, the use of phase-change materials appears to solve some of the current challenges, which include the mismatch between the slag temperature and the operating range of thermoelectric materials (Barati et al 2011). Using a second-law analysis, Bisio (1997) concludes that using air heated by slag heat recovery for combustion in the hot blast stoves of the BF is preferable to producing steam from the recovered heat.…”

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confidence: 99%

“…Recovery as hot air or steam is the most developed of the three, with large-scale trials demonstrating recovery efficiencies up to 65 percent. The latter two strategies are emerging as next-generation methods of BF slag waste heat recovery (Barati et al 2011). Barati et al (2011) evaluated these three technologies and found that, for both thermal and chemical energy recovery, a two-step process would yield a high efficiency with minimal technical risk.…”

mentioning

confidence: 99%

“…The latter two strategies are emerging as next-generation methods of BF slag waste heat recovery (Barati et al 2011). Barati et al (2011) evaluated these three technologies and found that, for both thermal and chemical energy recovery, a two-step process would yield a high efficiency with minimal technical risk. For thermoelectric power generation, the use of phase-change materials appears to solve some of the current challenges, which include the mismatch between the slag temperature and the operating range of thermoelectric materials (Barati et al 2011).…”

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confidence: 99%

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Emerging Energy-efficiency and Carbon Dioxide Emissions-reduction Technologies for the Iron and Steel Industry

Hasanbeigi¹

2013

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Iron and steel manufacturing is among the most energy-intensive industries and accounts for the largest share, approximately 27 percent, of global carbon dioxide (CO 2 ) emissions from the manufacturing sector. The ongoing increase in world steel demand means that this industry's energy use and CO 2 emissions continue to grow, so there is significant incentive to develop, commercialize and adopt emerging energy-efficiency and CO 2 emissions-reduction technologies for steel production. Although studies from around the world have identified a wide range of energy-efficiency technologies applicable to the steel industry that have already been commercialized, information is limited and/or scattered regarding emerging or advanced energyefficiency and low-carbon technologies that are not yet commercialized. This report consolidates available information on 56 emerging iron and steel industry technologies, with the intent of providing a well-structured database of information on these technologies for engineers, researchers, investors, steel companies, policy makers, and other interested parties. For each technology included, we provide information on energy savings and environmental and other benefits, costs, and commercialization status; we also identify references for more information.

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Energy recovery from high temperature slags

Cited by 266 publications

References 22 publications

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

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

Multi-Stage Control of Waste Heat Recovery from High Temperature Slags Based on Time Temperature Transformation Curves

Emerging Energy-efficiency and Carbon Dioxide Emissions-reduction Technologies for the Iron and Steel Industry

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