Heat Recovery from the Incineration of Polychlorinated Biphenyls Waste in Rotary Kilns (original) (raw)
Related papers
Numerical analysis of the incineration of polychlorinated biphenyl wastes in rotary kilns
Journal of Environmental Chemical Engineering, 2016
Polychlorinated biphenyls (PCBs) wastes are among hazardous wastes that must be incinerated for environmental and human health reasons. The incineration process of polychlorinated biphenyls (PCBs) wastes in a rotary kiln are governed by a dynamic model consist of a set of nine stiff nonlinear equations. The dynamic model accounts for variations in composition of PCBs on number of chlorine atoms and process conditions such as excess air, temperature and pressure of operation. To solve these equations, a MATLAB routine is written which is used to study the PCBs waste incineration processes. The results are presented and discussed on the holdups of ash, oxygen, carbon dioxide, water vapor, hydrochloric acid, methane, and gas at different conditions.
International Journal of Mechanical Systems Engineering, 2015
Polychlorinated Biphenyls (PCBs) are among hazardous wastes that must be incinerated for environmental and health protection. A dynamic model is introduced for the incineration of Polychlorinated Biphenyls (PCBs) in a rotary kiln. The model accounts for variations in composition and process conditions. The effects of excess air and the number of chlorine atoms in the structure of the PCBs are included in the incineration process. A MATLAB code was developed to solve the set of stiff nonlinear equations of PCBs incineration. The proposed incineration model was found to be in good agreement with the experimental data reported in the literature under ordinary feeding conditions for chlorinated compounds.
Thermal treatment of hazardous wastes: a comparison of fluidized bed and rotary kiln incineration
Energy & Fuels, 1993
Large volumes of sludge are produced by a wide variety of industrial processes and by municipal waste water treatment. Interest in incinerating these sludges, either alone or co-fired with other fuels, is increasing. The issues surrounding sludge incineration in rotary kilns and fluidized beds were identified through a series of pilot-scale tests using two slightly different paper mill sludges.
Combustion Modelling of a Rotary Kiln for Hazardous Waste Incineration
Incineration is an excellent disposal technology for all waste materials with heat release potentials, and provides high degree of toxic destruction and control for a broad range of hazardous materials. In the Netherlands, the hazardous wastes in various forms are processed at AVR-Chemie located at the Rotterdam harbour, through rotary kiln incinerators. The newly enforced regulations from the European Union with stricter emission levels require a better understanding of the incineration process and improved process control. However, the transport phenomena and combustion processes within the kiln system are very complex and not well understood. In order to get better understanding of the incineration process within the rotary kiln system, research was carried out to study the fluid flow and combustion behaviour of the incineration system. Computational Fluid-dynamics (CFD) was used to simulate the waste combustion process, and temperature measurements of the operating rotary kiln incinerator were conducted to validate the CFD model and to provide the information to kiln operators at AVR. This paper will present the latest results from the current research project for the simulation of gas flow and mixing, and combustion heat transfer for a wide range of hazardous waste streams.
Combustion Modeling of a Rotary-Kiln Hazardous Waste Incinerator
Hazardous waste has very complicated chemical compositions in a variety of physical forms and is difficult to characterize. Due to the complex transport phenomena within the incinerator the incineration process expects large uncertainties in the process chemistry and thermal/ emission control. For better understanding of the incineration process, process simulation was conducted using Computational Fluid-dynamics (CFD) to characterize temperature and species distribution in the incinerator. Hazardous waste in various forms is firstly converted to a hydrocarbonbased virtual fuel mixture. The combustion of the simplified waste was then simulated with a global 3-gas and an extended 7-gas combustion model. The distribution of temperature and chemical species is broadly investigated. The predicted temperature distribution has been validated with available measurement data from the operating rotary kiln waste incinerator AVR-Chemie in the Netherlands. New statistical post-processing of the standard CFD-output has been developed to give an overview of the average temperature profile and overall reactor behavior as valuable contribution to process control. Finally, an attempt has been made to simulate the multi-phase flow of the shredded solid waste within the incinerator in order to optimize the burner design.
MODELING AND SIMULATION OF A SOLID WASTE INCINERATION SUSTAINABLE ENERGY SYSTEM
Urban solid waste generation has drastically grown around the world, requiring creative, ecologically correct and sustainable solutions to be developed. This work considers a problem of thermodynamic optimization of extracting the most energy from a stream of hot exhaust produced by urban solid waste incineration, considering a stoichiometric combustion model, when the contact heat transfer area is fixed. For that, a mathematical model is introduced to evaluate the rate of heat generation due to the waste incineration process, and the exergetic (power) rate captured by a heat recovery steam generator (heat exchanger). The numerical results show that when the (cold) receiving stream boils in the counterflow heat exchanger; the thermodynamic optimization consists of locating the optimal capacity rate of the cold current. At the optimum, the cold side of the heat transfer surface is divided into three sections: preheating of liquid, boiling and superheating of steam. Experimental results are in good qualitative and quantitative agreement with the numerically calculated mathematical model results. Microalgae cultivated in large-scale vertical tubular compact photobiorreactors are investigated to treat the emissions produced by the incineration, and to increase the efficiency of the global system via cogeneration of co-products with high aggregated commercial value. NOMENCLATURE A area, m 2 í µí± í µí±í µí± specific heat of steam at constant pressure, J/kg K í µí± í µí± specific heat at constant pressure, J/kg K ℎ í µí± , ℎ í µí± Enthalpy of input and output J/kg í µí±̇ mass flow rate, kg/s í µí± mass M ration of mass flow rates
Modelling of a Dual Purpose Plant for Waste Incineration
In the present paper, the modelling of a dual-purpose plant for the production of electrical and thermal energy from the heat treatment of wastes is presented. Particularly, the model has been developed with the aim of performing a study about the simulation of a solid waste incineration process, which involves complex gas-solid reactions, in a fluidized bed combustor. The incineration plant is made of three sections, and namely a RDF combustion section, a flue gas treatment section and a thermal recovery section. This paper is mainly focused on the combustion section. Model results have been compared with the experimental data obtained derived from literature, showing a very good agreement. The proposed model may represent a useful and a reliable instrument to be used in both design and planning of new plants and in control and retrofit of existing plants.
CFD modeling of incinerator to increase PCBs removal from outlet gas
Journal of Environmental Health Science and Engineering, 2015
Incineration of persistent organic pollutants (POPs) is an important alternative way for disposal of this type of hazardous waste. PCBs are very stable compounds and do not decompose readily. Individuals can be exposed to PCBs through several ways and damaged by their effects. A well design of a waste incinerator will convert these components to unharmfull materials. In this paper we have studied the design parameters of an incinerator with numerical approaches. The CFD software Fluent 6.3 is used for modelling of an incinerator. The effects of several baffles inside the incinerator on flow distribution and heat is investigated. The results show that baffles can reduce eddy flows, increase retaining times, and efficiencies. The baffles reduced cool areas and increased efficiencies of heat as maximum temperature in two and three baffle embedded incinerator were 100 and 200°C higher than the non-baffle case, respectively. Also the gas emission leaves the incinerator with a lower speed across a longer path and the turbulent flow in the incinerator is stronger.