Efficiency and Exergy Enhancement of ORC Powered by Recovering Flue Gases-Heat System in Cement Industrials: a Case Study (original) (raw)
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International Journal of Industry and Sustainable Development
Alexandria National Refining and Petrochemicals Company (ANRPC) is a refinery in Alexandria, Egypt. A considerable amount of heat is wasted from the steam system after being utilized by different processes within the refinery. The utilized steam which can be recovered has an average flow rate of 15 Ton/hour, an average pressure of 4.5 bar, and an average temperature of 180°C~220°C. The company decides to conduct a cost-benefit analysis to assess the feasibility of a proposed Organic Rankine Cycle (ORC) system to convert this waste heat into electric power. The approach used in this study is mainly an industry perspective. It deals with the ORC unit as an investment opportunity, with its associated cost and benefits rather than its thermodynamic performance, which was discussed in several previous papers. The most two important questions to be answered are: what is the total cost of the ORC system (including the unit price, transportation, customs, installation, integration with the process, commissioning, and startup), and what are the financial benefits of the project (including the yearly energy saving, the decrease in the peak load, and the corresponding carbon dioxide (CO 2) emission reduction). This paper aims to be a guide for the decision-makers in the industry to support their decisions concerning the feasibility of installing ORC systems to recover waste heat and convert it into power. Based on the heat content of the waste heat stream and the efficiency of the evaporator (heat exchanger) of the working organic fluid, we can calculate the power that could be generated from the turbine (expander), and based on the efficiency of the generator, we can calculate the electrical power that can be generated (recovered) from the waste heat. In our case study, the expected generated electric power is 1,750 kW or equivalently, 15,000,000 kWh of electrical energy annually. Financial analysis shows that the ORC system, including the cost of the unit plus the costs of installation and integration into the process, will cost approximately 4.8 Million USD. The payback period is 4 years. The ORC unit will reduce the CO 2 emissions as a result of not generating this amount of energy using traditional methods by approximately 7,500 Ton annually. The ORC technology is an attractive solution for industries seeking for utilizing their waste heat to generate power, hence, decreasing their energy bills and contributing to reducing CO 2 emissions and combating global warming and climate change.
ORC waste heat recovery in European energy intensive industries: Energy and GHG savings
Energy Conversion and Management, 2013
Organic Rankine Cycle (ORC) is a technology with important opportunities in heat recovery from energy intensive industrial processes. This paper represents the first comprehensive estimate of ORC units that can be installed in cement, steel, glass and oil&gas industries in the 27 countries of the European Union based on an accurate methodology related to real plants in operation or under construction. An evaluation of energy savings, depending on the number of operating hours per year and of the consequent decrease in CO 2 emission and electricity expenditure, is also provided. The study, carried out in the framework of an European research project on heat recovery in energy intensive industries, found that, in the most convenient considered scenario, up to about 20,000 GW h of thermal energy per year can be recovered and 7.6 M ton of CO 2 can be saved by the application of ORC technology to the investigated and most promising industrial sectors.
Iraqi Journal of Industrial Research
This study investigates the feasibility of installing a waste heat recovery system (WHR) in a cement factory in Iraq using the organic thermal Rankine cycle (ORC). Heat losses in the cement industries represent high energy consumption percentages of the total energy inputs. The production of clinker is a sub-process in the cement manufacturing plant and consumes three quarters of the total energy used as heat from combustion. The main sources of waste heat in the cement plant are identified, from these sources of waste heat from the kiln surface to the air, hot air coming out of the clinker cooler, and preheating exhaust gases. It is possible to obtain the total waste heat from these sources in the range of 35-40% of the total heat input. This waste heat energy can be exploited by installing a waste heat recovery system in these plants to generate electricity. It is possible to generate electrical energy by 5.9 MW. When using an organic system to recycle hot gases in plants whose da...
The present work discusses the options of Waste Heat Recovery (WHR) in Algerian cement industry. Steam and Organic Rankine Cycle (SRC and ORC) solutions are proposed to recover the waste heat of a cement industry located in the North of Algeria. A thermodynamic optimization of both cycles is performed with the aim of maximizing each WHR unit net power output. To do that, the specific boundary conditions of Algeria are taken into account as well as real data acquired on the plant are used to set the optimizer. For the optimization, a model implemented in MATLAB environment linked with REFPROP and Coolprop databases has been developed, validated and used. The tool provides the optimize design in terms of architecture for both steam and organic Rankine cycles, and selects the most promising ORC working fluids among 124 candidates implemented in its dataset. Then, an economic and environmental analyses are performed on the most efficient solutions, as a way to determine their economic return and environmental sustainability. The addition of an oil thermal loop between the heat source and the organic fluid is also considered. Results show that the ORC recuperative configuration using acetone as working fluid is the most appropriate for this application from a technical, economic, and environmental point of view. The ORC unit exploits the exhaust gas waste heat released from the preheater tower at an average temperature of 382°C and achieves a net power output of 2.94 MW, with a payback time of 5.7 years. The environmental impact in terms of GWP and TEWI is very low.
Thermodynamic Analysis of ORC and Its Application for Waste Heat Recovery
Sustainability
The analysis and optimization of an organic Rankine cycle (ORC) used as a bottoming cycle in the Brayton/ORC and steam Rankine/ORC combined cycle configurations is the main focus of this study. The results show that CO2 and air are the best working fluids for the topping (Brayton) cycle. Depending on the exhaust temperature of the topping cycle, Iso-butane, R11 and ethanol are the preferred working fluids for the bottoming (ORC) cycle, resulting in the highest efficiency of the combined cycle. Results of the techno-economic study show that combined Brayton/ORC cycle has significantly lower total capital investment and levelized cost of electricity (LCOE) compared to the regenerative Brayton cycle. An analysis of a combined steam Rankine/ORC cycle was performed to determine the increase in power output that would be achieved by adding a bottoming ORC to the utility-scale steam Rankine cycle, and determine the effect of ambient conditions (heat sink temperature) on power increase. For...
Energy Conversion and Management, 2017
There is large amount of waste heat resources in industrial processes. However, most low-temperature waste heat is directly discharged into the environment. With the advantages of being energy-efficient, enabling investment-savings and being environmentally friendly, the Organic Rankine Cycle (ORC) plays an important role in recycling energy from low-temperature waste heat. In this study, the ORC system driven by industrial low-temperature waste heat was analyzed and optimized. The impacts of the operational parameters, including evaporation temperature, condensation temperature, and degree of superheat, on the thermodynamic performances of ORC system were conducted, with R113 used as the working fluid. In addition, the ORC-based cycles, combined with the Absorption Refrigeration Cycle (ARC) and the Ejector Refrigeration Cycle (ERC), were investigated to recover waste heat from low-temperature flue gas. The uncoupled ORC-ARC and ORC-ERC systems can generate both power and cooling for external uses. The exergy efficiency of both systems decreases with the increase of the evaporation temperature of the ORC. The net power output, the refrigerating capacity and the resultant exergy efficiency of the uncoupled ORC-ARC are all higher than those of the ORC-ERC for the evaporation temperature of the basic ORC >153 °C, in the investigated application. Finally, suitable application conditions over other temperature ranges are also given.
Jurnal Teknik ITS, 2016
Cement plant produce large amount of heat source in cement making process, due to inefficiency of system there still waste heat available in form of flue gas that can be utilize. Flue gas in cement plant can be utilized as alternative power generation. With the 200-300 o C temperature output range of flue gas from suspension preheater and air quenching cooler (AQC) in cement plant, organic rankine cycle (ORC) can be suitable option for alternative power generation. ORC is development of rankine cycle, the different is the working fluid in ORC using refrigerant.In cement plant that produce 8466 TPD kiln production, used flue gas from suspension preheater to dry raw material and produce 163888 m3/h flue gas from AQC that still not utilized. Flue gas with 235 o C temperature from AQC can utilized for power generation purpose using ORC system. Waste heat recovery calculation carried out to know the potential recovery. Operating condition of the ORC system will determine power produced that can be generated and ORC components calculated and selected according to the operating condition of the system.Using R141b as working fluid with 8 bar pressure and 110 o C temperature inlet to turbine, power produced by turbine is 666 kW. For the components, evaporator and condenser use shell and tube heat exchanger, with evaporator heat transfer area is 676.49 m2 while condenser has 510 m2 of heat transfer area. And for working fluid pump it needs 16.235 Kw power to pump R141b back to evaporator.
2021
Cement factories are among the most energy-intensive industries due to the huge consumption of the clinker manufacturing process (3.2-6.3 GJ ton-1). In addition, the process is characterized by high energy losses since there are two sources of waste heat at high temperature. To improve the system overall efficiency and reduces its emission per ton of cement produced, in this work the authors evaluate the benefits of installing an organic Rankine cycle (ORC) unit adopting low GWP working fluids to recover the waste heat. To design and optimize the ORC cycle, a tool has been developed in MATLAB environment and linked with REFPROP and CoolProp databases. It permits to determine the most appropriate cycle configuration between two different options, and to select the working fluid among 12 low GWP organic media. Being the waste heat at relatively high-temperature values, multistage turbines are used, and a thermal loop is adopted between the waste heat fluxes and the organic fluid for safety reasons. The waste heat sources operating conditions are acquired during an experimental campaign conducted on an in-operation cement industry located in the North of Algeria. The two identified heat sources are recovered via an oil loop and used to feed the ORC. The thermodynamic optimization in terms of net power output is performed, while an economic analysis is carried out to verify the feasibility of the technology through the Algerian techno-economic conditions. The optimization outcomes reveal that the recuperative configuration using pentane as working fluids guarantees the best thermodynamic performance while isopentane and R1233zd(E) guarantee to achieve a net output power 2.1% and 4.6% lower than pentane. However, the economic analysis reveals that the ORC adopting R1233zd(E) ensures the best economic results. Thus, considering also the environmental and safety aspects, the choice fell on the recuperative configuration using R1233zd(E) as working medium which guarantees a net power output of 3.33 MW, a net present value of 6.39 M$, a payback time of 7 years and a higher environmental sustainability.
Energetic and exergetic analysis of waste heat recovery systems in the cement industry
Energy, 2013
In a typical cement producing procedure, 25% of the total energy used is electricity and 75% is thermal energy. However, the process is characterized by significant heat losses mainly by the flue gases and the ambient air stream used for cooling down the clinker (about 35%e40% of the process heat loss). Approximately 26% of the heat input to the system is lost due to dust, clinker discharge, radiation and convection losses from the kiln and the preheaters. A heat recovery system could be used to increase the efficiency of the cement plant and thus contribute to emissions decrease. The aim of this paper is to examine and compare energetically and exergetically, two different WHR (waste heat recovery) methods: a water-steam Rankine cycle, and an Organic Rankine Cycle (ORC). A parametric study proved that the water steam technology is more efficient than ORC in exhaust gases temperature higher than 310 C. Finally a brief economic assessment of the most efficient solution was implemented. WHR installations in cement industry can contribute significantly in the reduction of the electrical consumptions operating cost thus being a very attractive investment with a payback period up to 5 years.