14:00
Session 2D: Waste heat (1)
Chair: Steven Lecompte
14:00
20 mins
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The Application of ORC Systems for Waste Heat Recovery in Metal Smelting Industry
Piotr Kolasiński
Abstract: The metal smelting industry is characterized by significant emission of waste heat. This applies to both ironworks and non-ferrous smelters. In various technological processes related to the processing of metal ores, waste substances (in the form of liquids and gases) are released. These include cooling water and oils, slag disposal, throat gas, blast furnace gas, converter gas and other waste gases. Significant amounts of waste heat are also emitted from smelting products (castings, etc.). At different stages of metal production, different waste heat carriers are emitted at the different temperature and capacity levels. The assessment of the applicability of the heat source for the heat recovery requires a multi-aspect analysis of the heat source's characteristics as well as chemical aggressiveness and contamination of the carrier. In many cases, waste gases are containing components which are harmful and aggressive to construction materials. Moreover, the capacity of these gases is often floating.
Due to the high power of waste heat sources generated in metal processing industries, ORC systems are promising for heat recovery application. The article presents an analysis of the applicability of ORC systems for waste heat recovery in this branch of industry. The output and thermal characteristics of generated waste heat sources are comprehensively discussed in first part of this paper. The thermal power of these sources is then determined and the calculation models of ORC systems dedicated to waste heat recovery from these sources are proposed. Model calculations were carried out and the results of modelling on the ORC systems operating parameters and their performance are presented in this article. Modelling was carried out for various working fluids with a vaporization temperature appropriate for the temperature range of the different heat sources. The results of the analyses indicate that the potential of waste heat sources generated in smelting industry is significant and ORC system is a promising technology for application in this branch of industry.
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14:20
20 mins
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Thermodynamic and Thermo Economic Analysis of Organic Rankine Cycle with Multi-objective Optimization for Working Fluid Selection with Low- Temperature Waste Sources in the Indian Industry
Bipul Krishna Saha, Basab Chakraborty, Prashant Pundeer
Abstract: Sustainability and environmental protection have become an important issue in the energy-intensive industry. Driven by this, targets have been set to reduce the dependency on fossil fuels for lowering the carbon dioxide emission and sustainable energy use. In India, availability of low-grade waste heat (less than 400 °C) finds an extensive opportunity in increasing the energy efficiency for the industry. The Organic Rankine cycle (ORC) and Regenerative-ORC are considered to be promising technologies to recover the low-grade industrial waste heat. In this work, fifty-one potential working fluids have been studied for the ORC and RORC system. Non-dominated sorting genetic algorithm (NSGA-II) was exploited to perform multi-objective optimization of thermodynamic performance and economic analysis of the process using the working fluids. Optimal compromise solutions were selected from Pareto frontiers (as obtained from NSGA-II) using fuzzy set theory for all the fifty-one potential working fluids. Based on the selected optimal solution, the efficiency of the cycle and total plant set-up cost was determined. Propylene was found to perform the best in both the ORC and RORC systems. The result was used to calculate an explicit evaluation index in economic performance (static investment payback period). Furthermore, a fast decision-making method was developed for the optimal selection of the working fluid using key physical parameters of the respective fluids.
Reference:
1. Krishna B, Basab S. Utilization of low-grade waste heat-to-energy technologies and policy in Indian industrial sector : a review. Clean Technol Environ Policy 2017;19:327–47. doi:10.1007/s10098-016-1248-2.
2. Saha B K, Chakraborty B, Sam AA, Ghosh P. Performance Analysis of Organic Rankine Cycle Technology to Exploit Low-Grade Waste Heat to Power Generation in Indian Industry 2017; doi:11:1072–8.
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14:40
20 mins
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CASE Study of an Organic Rankine Cycle (ORC) for Waste Heat Recovery from Cogeneration Systems
Talieh Rajabloo, Koen Allaerts
Abstract: Waste heat is one of the important energy losses which has attracted attention to be captured and utilized or to be converted into electricity. As for the conversion concept, ORC is a developing technology [1]. The waste heat is available from different industrial sources such as flue-gas exhausts, offshore oil and gas processing platforms, kilns in the cement and steel industries and also combined heat and power plants (CHP). Several studies showed the potential of combined heat and power technology in energy intensive sectors. As an example, Alipour [2] concludes that the profitability of these CHP plants can be improved by selling excess heat to nearby customers.
In this study the feasibility of an ORC driven by waste heat from a CHP plant has been investigated thermodynamically. A bio based gas turbine in Flanders was selected as a case study and its waste heat properties were considered as input to a model of an ORC plant. The exhaust gas temperature at full load is 427 (°C) in which the recoverable temperature for ORC can, roughly, be 180 (°C). Setting return temperature and the related evaporation pressure, the maximum cycle efficiency was obtained around 17% with a potential power generation of 180.6 kWe. Although this efficiency depends on several parameters such as the location and seasonal/ambient temperatures, the first step of the study showed acceptable outcomes. Currently the impact of various cooling technologies on the ORC performance is being investigated .
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15:00
20 mins
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Performance Analysis of an Organic Rankine Cycle for Integration in a Carnot Battery
Aditya Pillai, Alihan Kaya, Michel De Paepe, Steven Lecompte
Abstract: The purpose of this study is to report the challenges associated with the design of an ORC setup to be connected to a power-heat-power system, also known as a Carnot battery. Power is converted to heat using a high-temperature heat pump (HT-HP) and is stored using a separate sensible and latent heat storage system, consisting respectively of a phase change material (PCM) i.e., molten salt and pressurized hot water. Simulations are carried out in Python and Engineering Equation Solver (EES) to investigate the effect of the two storage systems on the performance of the ORC considering different working fluids. Working fluids that have low global warming potential (GWP) and zero ozone depleting potential (ODP) are considered. Minimizing irreversibilities during pre-heating and evaporating is of key importance. The identified working fluids of interest are HFO-1336mzz(E) & R1234ze(Z). The exergy destruction in the ORC increases by 73 % if R1234ze(Z) is used as the working fluid. Finally, based on the acquired results, a preliminary test-rig is developed with a volumetric piston expander. The net power output from the test-rig is estimated to be approximately 10 kWe.
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