Comparison of Emissions from Burning Hazardous Waste in a Dry-Process Cement Kiln with Emissions from Burning Conventional Fossil Fuels

1994 ◽  
Vol 11 (1) ◽  
pp. 193-199 ◽  
Author(s):  
JOHN R. HART
Keyword(s):  
Hazardous Waste ◽  
Fossil Fuels ◽  
Cement Kiln ◽  
Dry Process

CFD Simulation of Large Dust Collection Cyclones Positioned Vertically in Staggered Downward Cascade Arrangement

2013 ◽  
Author(s):  
Eugen-Dan Cristea ◽  
Pierangelo Conti
Keyword(s):  
Cfd Simulation ◽  
Solid Phase ◽  
Phase Particle ◽  
High Mass ◽  
Cfd Modeling ◽  
Cement Kiln ◽  
Dust Collection ◽  
Dry Process ◽  
Cascade Arrangement ◽  
Simulation Results

Three dimensional, time dependent Euler-Euler simulation approach for numerical calculation of multiphase strongly swirling turbulent gas-heavy laden particulate flow in large industrial collection cyclones, positioned vertically, in staggered downward cascade arrangement has been performed. The multiphase flow was featured high mass loading. This paper specifically addresses a CFD modeling of a “suspension preheater”, typical equipment for dry process cement kiln. Big sized cyclone separator is a key component of this device. The simulation case study was developed in the frame of the commercial general-purpose code ANSYS-Fluent R13. In cyclone separators the swirling gas motion induces a centrifugal force on the solid particulate phase which is the driving force behind the separation process. The turbulence disperses the solid particulates and enhances the probability that particles are discharged, as reject. Both phenomena are related to solid phase particle size distribution (PSD) and flow pattern into the collection cyclones. The multiphase turbulence was modeled using the RSM Mixture Turbulence Model. The simulation results were validated against industrial measurements carried out on an industrial suspension preheater, in the frame of heat and mass balance of cement kiln energy audit. The numerical simulation results were found in reasonable agreement with the collected industrial measurements. This CFD simulation represents a powerful engineering tool on behalf of the cement process engineer either for new cutting-edge design or for performance verification of an existing plant.

Disposal of hazardous industrial waste in cement kiln – A pilot study of acid tar sludge

2021 ◽  
pp. 0734242X2110555
Author(s):  
Rahul Baidya ◽  
Sadhan Kumar Ghosh
Keyword(s):  
Hazardous Waste ◽  
Feed Rate ◽  
Treatment Plant ◽  
Ambient Air ◽  
Cement Kiln ◽  
Cement Plant ◽  
Hazardous Waste Disposal ◽  
Alternative Means ◽  
Central Pollution Control Board ◽  
Disposal Problem

Acid tar sludge (ATS) is a hazardous waste generated in steel plants as a process by-product. ATS disposal is a major challenge for the steel industry around the world and specifically for developing nations. Hazardous wastes are usually disposed of in a dedicated expensive thermal treatment plant as per existing rules. Due to inadequate capacity of treating the total amount of hazardous waste, study of other economical options are required. India generates over 7.2 million metric tonnes of hazardous waste annually as per Central Pollution Control Board (CPCB), Government of India. Thus, co-processing of ATS in cement plant as an alternative means of disposal was studied based on a number of trials. During the five trials of 5 day each, feed rate of ATS was maintained at 0.4 tonne per hour (TPH) with an average coal feed rate of 10 TPH. No incremental variations in emissions were observed during the trials. The analysis further revealed insignificant impact on clinker quality, leach behaviour and cement property. The study also showed negligible impact on ambient air quality based on NO x, SO2, RSPM, SPM measurement at varying location around the cement plant. Thus, co-processing of hazardous waste such as ATS in cement plant can be an effective way to address the hazardous waste disposal problem in developing countries such as India.

NOx Reduction Review on Fuel Alternative in Cement Kiln

2013 ◽  
Vol 864-867 ◽  
pp. 1626-1629
Author(s):  
Hai Bing Liu ◽  
Xiao Dong Chen ◽  
Jun Gu
Keyword(s):  
Nitrogen Content ◽  
Fossil Fuels ◽  
Nox Reduction ◽  
Reducing Agent ◽  
Environmental Benefits ◽  
Nox Emission ◽  
Cement Kiln ◽  
Cement Kilns ◽  
Low Nitrogen

The paper first discusses the relativity between alternative combustion andNOx emissions by a test in dry cement kiln, and a lot of case on fuel alternative The main findings of the study are that the use of RDF in cement kilns instead of coal or coke offers environmental benefits and reduce NOx emission. The conclusion is that the NOx generation can probably be lower because of lower flame temperatures or lower air excess and low nitrogen content in comparison with fossil fuels also is impartment reason., another a fact that most of the nitrogen (N) in biomass is released as ammonia (NH3) which acts as a reducing agent with NOx to form nitrogen (N2).

Computer Simulation of Heat Transfer in Alumina and Cement Rotary Kilns

2021 ◽  
pp. 1-57
Author(s):  
Atinder Pal Singh ◽  
P.S. Ghoshdastidar
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
Rotary Kiln ◽  
Cement Kiln ◽  
Gas Temperature ◽  
Contact Heat ◽  
Dry Process ◽  
Radiation Exchange ◽  
Covered Wall ◽  
Rotary Kilns

Abstract The paper presents computer simulation of heat transfer in alumina and cement rotary kilns. The model incorporates radiation exchange among solids, wall and gas, convective heat transfer from the gas to the wall and the solids, contact heat transfer between the covered wall and the solids, and heat loss to the surroundings as well as chemical reactions. The mass and energy balances of gas and solids have been performed in each axial segment of the kilns. The energy equation for the wall is solved numerically by the finite-difference method. The dust entrainment in the gas is also accounted for. The solution marches from the solids inlet to the solids outlet. The kiln length predicted by the present model of the alumina kiln is 77.5 m as compared to 80 m of the actual kiln of Manitius et al. (1974, Manitius, A., Kurcyusz, E., and Kawecki, W., “Mathematical Model of an Aluminium Oxide Rotary Kiln,” Ind. Eng. Chem. Process Des. Dev., 13 (2), pp. 132-142). In the second part, heat transfer in a dry process cement rotary kiln is modelled. The melting of the solids and coating formation on the inner wall of the kiln are also taken into account. A detailed parametric study lent a good physical insight into axial solids and gas temperature distributions, and axial variation of chemical composition of the products in both the kilns. The effect of kiln rotational speed on the cement kiln wall temperature distribution is also reported.

Distributions of Cr, Ni, Cu and Zn in Hazardous Waste Co-Processing in a Pilot-Scale Rotary Cement Kiln

2011 ◽  
Vol 12 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Jenwit Krobthong ◽  
Manaskorn Rachakornk ◽  
Viboon Sricharoen
Keyword(s):  
Hazardous Waste ◽  
Pilot Scale ◽  
Cement Kiln ◽  
Rotary Cement Kiln ◽  
Cu And Zn

Hazardous Waste from Fossil Fuels

2004 ◽  
pp. 119-131 ◽  
Author(s):  
Majid Ghassemi ◽  
Paul K. Andersen ◽  
Abbas Ghassemi ◽  
Russell R. Chianelli
Keyword(s):  
Hazardous Waste ◽  
Fossil Fuels

Hybrid Eulerian Multiphase-Dense Discrete Phase Model Approach for Numerical Simulation of Dense Particle-Laden Turbulent Flows Within Vertical Multi-Stage Cyclone Heat Exchanger

2018 ◽  
Author(s):  
Eugen-Dan Cristea ◽  
Pierangelo Conti
Keyword(s):  
Heat Exchanger ◽  
Carrier Phase ◽  
Phase Model ◽  
Cement Kiln ◽  
Dispersed Phase ◽  
Discrete Phase Model ◽  
Dry Process ◽  
Rotary Cement Kiln ◽  
Multi Stage ◽  
Discrete Phase

This article describes a CFD engineering application developed to investigate numerically the multiphase, non-isothermal, turbulent flow physics within the suspension preheater of a dry-process rotary cement kiln. The multi–stage cyclone preheater is a counter-current heat exchanger. We used the CFD flow solver ANSYS-Fluent R18.1. to accomplish this task. The hybrid Eulerian multiphase-dense discrete phase model is a coupled Eulerian-Lagrangian technique. The primary carrier-phase is treated as a continuum by solving the Navier-Stokes equations, while the secondary discrete dispersed-phase is solved by tracking the particle parcels through the calculated flow field. The multiphase turbulence of the carrier-phase is modeled using the Reynolds stress transport model. The dispersed-phase interactions are modeled through the specific collisions models provided by the kinetic theory of granular flow and/or discrete element method. The Eulerian multiphase-DDPM method provided a quiet stable solution for a medium/high mass loading (solid to gas mass ratio 0.89:1). The four-stage cyclone suspension preheater is analyzed for its operating performance i.e. overall pressure drop and global collection efficiency of cyclone stages, calcination degree at bottom cyclone stage, flue gas temperature at 1st. cyclone stage and availability to get more insight of very complex multi-phase flow patterns within this equipment. The set of industrial measurements, collected during a heat and mass balance of a dry process rotary cement kiln, were used to verify and to validate part of the simulation results.

Experimental Study on the Re-Bonded Magnesia - Zirconia Refractory for New Dry Process Cement Kiln

2011 ◽  
Vol 287-290 ◽  
pp. 823-826
Author(s):  
Hui Fang Zhang ◽  
Hong Liang Huang ◽  
Li Fang Zhang ◽  
Na Zheng ◽  
Fei Zhao
Keyword(s):  
Experimental Study ◽  
Particle Size ◽  
Sinter Temperature ◽  
Polyvinyl Alcohol ◽  
Hexavalent Chromium ◽  
Raw Material ◽  
Cement Kiln ◽  
Magnesite Powder ◽  
Dry Process ◽  
Zirconia Refractory

The use of magnesia-chrome refractories of the cement kiln can generate harmful hexavalent chromium in the environment and be hazardous to your health, so the study on the instead of magnesia-chrome refractories have become urgent issues. The raw material is made up of fused magnesite particles (particle size 0 to 3 mm), fine fused magnesite powder with the size less than 200 meshes and fine fused magnesia-zirconia’s powder with the size less than 320 meshes, polyvinyl alcohol and calcium lignosulfonate liquor being used as the combine. This paper discusses the effect of sinter temperature on sinter character of products.

Effects of Nickel on Properties of Cement Mortar Derived from the Co-Burning of Industrial Waste and its Leaching Behavior

2015 ◽  
Vol 1103 ◽  
pp. 121-127
Author(s):  
Suthatip Sinyoung ◽  
Ekkachai Taweekitwanit ◽  
Puangrat Kajitvichyanukul
Keyword(s):  
Hazardous Waste ◽  
Alternative Fuels ◽  
New Technology ◽  
Xrd Analysis ◽  
Raw Material ◽  
Cement Kiln ◽  
Leaching Behavior ◽  
Free Lime ◽  
Leach Test ◽  
Alternative Material

Burning of hazardous waste in cement kiln is the new technology based on waste derived and alternative fuels. Besides being the alternative way to destroy hazardous waste, this method provides alternative material as raw material or the fuel in the cement production process. This disposal method can be applied if the contaminant either does not appear in the emission or leach from cement to environment. This work focused on properties and the leaching behavior of nickel from cement. The resulting clinker was analyzed for the content of free lime and X-ray diffraction (XRD) analysis was done. The identification of MgNiO2 peaks in XRD pattern was found in all clinkers with nickel addition in the range of 0.5-2.0 wt.%. Results obtained from this part suggested that nickel incorporated in the clinker phase and may combine with magnesium to form the new compound as MgNiO2 during the burning process. To study the leaching behavior, M3051A, NEN:7341 and pH static leach test were used. Results showed that approximately 3% of nickel can be leached to environment. From the pH static leach test, nickel was effectively leached at pH 4 and the reachability of its decreased when the pH increased. In this work, Toxicity characteristic leaching procedure (TCLP) was also used to identify the cement as hazardous waste or non-hazardous waste. The results showed that raw material doped with nickel up to 2 wt.%, the cement was not classified as hazardous waste.

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