Numerical Study on the Influence of Operational Settings on Refuse Derived Fuel Co-firing in Cement Rotary Kilns

Liedmann, B.; Wirtz, S.; Scherer, Viktor; Krüger, Benno

doi:10.1016/j.egypro.2017.07.176

Cited by 19 publications

(28 citation statements)

References 4 publications

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“…Therefore, following these complex issues which contribute to the inefficient energy use and emissions in cement kiln systems, there is a strong need to use computer-aided modelling to simplify the work of analyses. Other studies have tried to vary fuel properties, primary-and secondary air settings, and fuel feed location to study the effect of the operational setting on refuse-derived fuel, where the results show a good applicability of the presented modelling procedure [2][3][4][5].…”

Section: Introductionmentioning

confidence: 93%

“…There are several process parameters in a cement rotary kiln system, which should be studied in order to observe trends that may indicate problems and provide necessary mean data for process analysis. The most important kiln controlling parameters are clinker production rate, fuel flow rate, specific heat consumption, secondary air temperature, kiln feed-end temperature, preheater exhaust gas temperature, ID fan pressure drop, kiln feed-end percentage oxygen, percentage downcomer oxygen, primary air flow rate, specific kiln volume loading, specific heat loading of burning zone crosssection area, and cooler air flow rate including temperature, pressure, and oxygen profile of the preheater [1][2][3][4]. However, the principal control variables are burning zone solid material temperature typically aimed at T brn = 1500°C; feed-end gas temperature typical at T brn = 1000°C; and feed-end oxygen typical at 2% [1].…”

Section: Introductionmentioning

confidence: 99%

“…3 Journal of Energy observed that most of the studies concerning modelling and simulation of cement manufacturing processes that can be found in the literature are based on computational fluid dynamics (CFD) and use the ANSYS Fluent package. This software allows the modelling of the effect of surface condition and phase changes of the material, as well as the optimization of fluid flow, material feed, and containing structure [2][3][4][5]. Furthermore, by considering the nature of cement production, specific needs and purpose of conceptual process design, and research experience from the other authors [36][37][38][39], they identified the Aspen Plus software as the most suitable tool for flow sheeting modelling and simulation of cement plants.…”

Section: Introductionmentioning

confidence: 99%

“…In cement production processes, there are several models for the purpose of studying the use of alternative fuels [4,36,39]: phase chemistry [40], oxidation process of coal tar pitch [41], cement raw material blending process [42], reduction of CO 2 [43], sensitivity analysis of a model used for the design of rotary kiln processes [44], and a nonlinear model predictive control [45]. However, all these models do not address issues of real inefficiency taking place in cement production processes, equipment, and the overall system.…”

Section: Introductionmentioning

confidence: 99%

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Parametric Studies of Cement Production Processes

John

2020

Journal of Energy

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The cement industry is one of the most intensive energy consumers in the industrial sectors. The energy consumption represents 40% to 60% of production cost. Additionally, the cement industry contributes around 5% to 8% of all man-made CO2 emissions. Physiochemical and thermochemical reactions involved in cement kilns are still not well understood because of their complexity. The reactions have a decisive influence on energy consumption, environmental degradation, and the cost of cement production. There are technical difficulties in achieving direct measurements of critical process variables in kiln systems. Furthermore, process simulation is used for design, development, analysis, and optimization of processes, when experimental tests are difficult to conduct. Moreover, there are several models for the purpose of studying the use of alternative fuels, cement clinker burning process, phase chemistry, and physical parameters. Nonetheless, most of them do not address real inefficiency taking place in the processes, equipment, and the overall system. This paper presents parametric study results of the four-stage preheater dry Rotary Kiln System (RKS) with a planetary cooler. The RKS at the Mbeya Cement Company (MCC) in Tanzania is used as a case study. The study investigated the effects of varying the RKS parameters against system behaviour, process operation, environment, and energy consumptions. Necessary data for the modelling of the RKS at the MCC plant were obtained either by daily operational measurements or laboratory analyses. The steady-state simulation model of the RKS was carried out through the Aspen Plus software. The simulation results were successfully validated using real operating data. Predictions from parametric studies suggest that monitoring and regulating exhaust gases could improve combustion efficiency, which, in turn, leads to conserving fuels and lowering production costs. Composition of exhaust gases also depends both on the type of fuel used and the amount of combustion air. The volume of exit flue gases depends on the amount of combustion air and infiltrating air in the RKS. The results obtained from the study suggest a potential of coal saving at a minimum of about ṁcoal=1263 kg·h−1, which approximates to 76,126 tons per year at the current kiln feed of 58,000 kg·h-1. Thus, this translates to a specific energy saving of about 1849.12 kJ·kgcl-1, with relatively higher clinker throughput. In this vein, process modelling provides effective, safe, and economical ways for assessing the performance of the RKS.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Parametric Studies of Cement Production Processes

John

2020

Journal of Energy

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“…However, the highly heterogeneous nature of the RDF input (both physically and chemically) in comparison to more traditional fossil fuels limits the share of RDF used in the mix of a cement kiln. Ultimately, this leads to decreased efficiency in the production process, with adverse consequences on cement quality (Liedmann et al, 2017). On top of these rather technical challenges, dissenting voices in academic and activist circles point to the dangerous impacts this practice might have, given the absence of strict environmental guidelines, especially at a local level.…”

Section: Introductionmentioning

confidence: 99%

Wasting Democracy, Fueling Dissent: Refuse-Derived Fuels in Can Sant Joan (Catalonia)

Cayuela

Turhan

2019

Front. Energy Res.

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The cement industry is one of the most energy intensive in the world, contributing significantly to global greenhouse gas emissions. The use of refuse-derived fuels (RDF) in cement kilns is increasingly portrayed as a sustainable solution to reduce emissions while dealing with different types of waste. Nevertheless, the use of RDF in cement plants is contested by communities around the world, who are facing immediate environmental impacts. In this article, we examine the burgeoning movement against waste incineration in cement kilns legitimized as energy recovery. We start by revisiting the environmental justice literature, which laid the groundwork for the contemporary anti-RDF movement. Then, in order to highlight the energy dimension of RDF we focus on two energy-related concepts: energy justice and energy democracy. Through the case study of Can Sant Joan (Catalonia), we assess the suitability and usefulness of these concepts with the local movement against waste incineration. Our analysis suggests that the movement against RDF use can be further energized and strengthened by expanding into the realm of energy democracy. Both the anti-RDF and the energy democracy movement share a focus on the local scale, have similar typology of stakeholders involved, and favor a strong bottom-up approach while paying attention to unequal power relations. We also observe that these movements can mutually benefit from being better integrated with one another. Finally, we propose that a potential alliance between the Plataforma Antiincineració de Montcada i Reixac (PAMiR) and the Xarxa per la Sobirania Energètica (Xse) in Catalonia, can mobilize fruitful internal tensions toward a more inclusive and democratic future.

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