Case Study of an Organic Rankine Cycle (ORC) for Waste Heat Recovery from an Electric Arc Furnace (EAF)

Lecompte, Steven; Oyewunmi, Oyeniyi A.; Markides, Christos N.; Lazova, Marija; Kaya, Alihan; Broek, Martijn van den; Paepe, Michel De

doi:10.3390/en10050649

Cited by 71 publications

(28 citation statements)

References 52 publications

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“…In ref., a heat recovery concept for electric arc furnaces, whereby the heat is utilized as electricity and combined heating, is introduced. Within this concept, steam accumulators are smoothing the fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Modeling, Simulation, and Validation with Measurements of a Heat Recovery Hot Gas Cooling Line for Electric Arc Furnaces

Keplinger

Haider

Steinparzer

et al. 2018

steel research int.

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Waste heat recovery has a high potential for increasing the efficiency and sustainability of electric arc furnaces. In the present work, a dynamic model of a water cooled hot gas line is presented and validated with measurements of a newly installed electric arc furnace (EAF) with a waste heat recovery system. Due to necessary reconstruction work of the EAF, the cooling pass is upgraded to a heat recovery hot gas line. With hot water from the hot gas line saturated steam can be produced and fed into the existing steam net. The heart of the system is the water cooled hot gas line which is responsible for sufficient hot gas cooling on the one hand and adequate hot water generation for the steam generators on the other hand. The water cooled hot gas line is modeled in the commercial simulation software APROS and validated with measurements of the performance test during commissioning of the heat recovery plant. The simulation results are showing an excellent agreement to the measurements. The results embody that the model is both very reliable to estimate the transient behavior of the hot gas line and able to predict the operational process conditions.

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Section: Introductionmentioning

confidence: 99%

Modeling, Simulation, and Validation with Measurements of a Heat Recovery Hot Gas Cooling Line for Electric Arc Furnaces

Keplinger

Haider

Steinparzer

et al. 2018

steel research int.

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“…In order to compute the arc length in Equation (2), in this study, the effective voltage EV arc is computed per semi cycle and the dynamic behavior in the EAF model is incorporated by a variable voltage gradient in the arc length calculation. However, in the EAF modeling, some relations about the voltage gradient must be established in terms of voltages and currents.…”

Section: Arc Length Calculation Via Variable Voltage Gradientsmentioning

confidence: 99%

“…An electric arc furnace (EAF) [1] is an industrial device used for steel production and other important applications (e.g., [2]). The actual energy used in EAFs depends on the quality and conditions of the charge materials (scrap, direct reduced iron (DRI), and others), the amount of slag, and the total time of the heat.…”

Section: Introductionmentioning

confidence: 99%

Electric Arc Furnace Modeling with Artificial Neural Networks and Arc Length with Variable Voltage Gradient

Garcia-Segura

Castillo

Martell³

et al. 2017

Energies

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Electric arc furnaces (EAFs) contribute to almost one third of the global steel production. Arc furnaces use a large amount of electrical energy to process scrap or reduced iron and are relevant to study because small improvements in their efficiency account for significant energy savings. Optimal controllers need to be designed and proposed to enhance both process performance and energy consumption. Due to the random and chaotic nature of the electric arcs, neural networks and other soft computing techniques have been used for modeling EAFs. This study proposes a methodology for modeling EAFs that considers the time varying arc length as a relevant input parameter to the arc furnace model. Based on actual voltages and current measurements taken from an arc furnace, it was possible to estimate an arc length suitable for modeling the arc furnace using neural networks. The obtained results show that the model reproduces not only the stable arc conditions but also the unstable arc conditions, which are difficult to identify in a real heat process. The presented model can be applied for the development and testing of control systems to improve furnace energy efficiency and productivity.

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“…(a) electricity generation by Thermo-electric generator (TEG) arrays [14,15], (b) electricity generation by an Organic-Rankine Cycle (ORC) without a heat pump [16,17], (c) electricity generation by ORC turbines with a heat pump [18,19], and (d) direct utilization of the thermal exergy in the stack in a district energy system [20,21]. In all of the above methods (a)-(d), the forced-draught fan in the stack and fluid circulation pumps are necessary for claiming the thermal power exergy, in addition to the power conversion equipment.…”

mentioning

confidence: 99%

“…The electric power that is 168 generated by ORC turbines depends upon the source temperature while the First-Law efficiency is 169 around 10%. Lecompte et al[16] applied ORC technology to an electric arc furnace with a First-Law 170 efficiency of about 13%. This efficiency is higher when compared to other lower source temperature 171 applications.…”

mentioning

confidence: 99%

Development of an Exergy-Rational Method and Optimum Control Algorithm for the Best Utilization of the Flue Gas Heat in Coal-Fired Power Plant Stacks

Kılkış

2019

Energies

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Waste heat that is available in the flue gas of power plant stacks is a potential source of useful thermal power. In reclaiming and utilizing this waste heat without compromising plant efficiency, stacks usually need to be equipped with forced-draught fans in order to compensate for the decrease in natural draught while stack gas is cooled. In addition, pumps are used to circulate the heat transfer fluid. All of these parasitic operations require electrical power. Electrical power has unit exergy of almost 1 W/W. On the contrary, the thermal power exergy that is claimed from the low-enthalpy flue gas has much lower unit exergy. Therefore, from an exergetic point of view, the additional electrical exergy that is required to drive pumps and fans must not exceed the thermal exergy claimed. Based on the First-Law of Thermodynamics, the net energy that is saved may be positive with an apparently high coefficient of performance; however, the same generally does not hold true for the Second-Law. This is a matter of determining the optimum amount of heat to be claimed and the most rational method of utilizing this heat for maximum net exergy gain from the process, under variable outdoor conditions and the plant operations. The four main methods were compared. These are (a) electricity generation by thermoelectric generators, electricity generation with an Organic-Rankine Cycle with (b) or without (c) a heat pump, and (d) the direct use of the thermal exergy that is gained in a district energy system. The comparison of these methods shows that exergy-rationality is the best for method (b). A new analytical optimization algorithm and the exergy-based optimum control strategy were developed, which determine the optimum pump flow rate of the heat recovery system and then calculate how much forced-draft fan power is required in the stack at dynamic operating conditions. Robust design metrics were established to maximize the net exergy gain, including an exergy-based coefficient of performance. Parametric studies indicate that the exergetic approach provides a better insight by showing that the amount of heat that can be optimally recovered is much different than the values given by classical economic and energy efficiency considerations. A case study was performed for method (d), which shows that, without any exergy rationality-based control algorithm and design method, the flue gas heat recovery may not be feasible in district energy systems or any other methods of utilization of the heat recovered. The study has implications in the field, since most of the waste heat recovery units in industrial applications, which are designed based on the First-Law of Thermodynamics, result in exergy loss instead of exergy gain, and are therefore responsible for more carbon dioxide emissions. These applications must be retrofitted with new exergy-based controllers for variable speed pumps and fans with optimally selected capacities.

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Case Study of an Organic Rankine Cycle (ORC) for Waste Heat Recovery from an Electric Arc Furnace (EAF)

Cited by 71 publications

References 52 publications

Modeling, Simulation, and Validation with Measurements of a Heat Recovery Hot Gas Cooling Line for Electric Arc Furnaces

Modeling, Simulation, and Validation with Measurements of a Heat Recovery Hot Gas Cooling Line for Electric Arc Furnaces

Electric Arc Furnace Modeling with Artificial Neural Networks and Arc Length with Variable Voltage Gradient

Development of an Exergy-Rational Method and Optimum Control Algorithm for the Best Utilization of the Flue Gas Heat in Coal-Fired Power Plant Stacks

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