Papers by Keyword: Cement Kiln

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Authors: Jian Gang Wang, Pu Yan Zheng, Zhi Yun Zhou, Yan Zhou Yuan
Abstract: Power generation using waste heat from cement kiln can not only bring economic benefits to the enterprise, but also play an important role in environment protection. Constantly researches have proved that there is still large energy saving potential in its operation. In this paper, the waste heat power generation system was divided into several subsystems, and the exergy calculation model of each subsystem unit was established. Finally, the weakest part in energy use was found according to the results. It provides a scientific basis for performance improvement and energy saving transformation of waste heat power generation.
Authors: Tao Yue, Fan Wang, Bin Jie Han, Peng Lai Zuo, Fan Zhang
Abstract: The mercury emission characteristics of coal-fired power plant boilers, industrial boilers, cement kilns, and sintering of iron and steel industry were studied in this paper. The reducing effect of mercury emissions by pollution control technology was analyzed. The EPA standard method was used to measure the mercury concentration of the pollution sources. For coal-fired boilers, the mercury removal efficiency of the existing electrostatic precipitator and wet FGD is up to 60%-70%, and the mercury concentration in the flue gas is below the standard 30μg/Nm3. The main mercury emissions of cement industries are at the kiln outlet, the mercury concentration of which is 2.5 to 5.4 times that of the kiln inlet. For the iron and steel industry, the mercury concentration of the exhausting gas after dust removal and desulfurization can not meet the emission limits and need to be further controlled. The research did in the paper made a scientific basis for the improvement of atmospheric mercury emission inventory and the mercury control.
Authors: Tao Yue, Fan Wang, Bin Jie Han, Peng Lai Zuo, Fan Zhang
Abstract: The heavy metals including Pb, Cd, Cr, As and Mn emission characteristics of coal-fired power plant boilers, industrial boilers, lead and zinc smelters, cement kilns, and steel industries were studied in this paper. The removing effects of heavy metals by pollution control technology were analyzed. ICP-AES method was used to measure the contents of heavy metals in solid samples. In addition, M-29, the U.S. EPA isokinetic sampling method was used to sample heavy metals in the flue gas, and the sampled heavy metals were tested by ICP-AES-hydride generator system. For coal-fired boilers, heavy metal contents in descending order were Mn, Pb and Cd in the tested coal. The heavy metals’ emission concentrations of coal-fired industrial boilers were much higher than the heavy metals’ emission concentrations of power plants. For the lead and zinc smelters, Pb and its compounds in flue gas after cleaning can meet the emission standards. The heavy metal contents in the cement raw materials in descending order were Pb, Cr and Cd. For the sintering mixture, the heavy metal contents in descending order were Pb, Cr and Cd as well. The removal effects of heavy metals by existing pollutant control technologies in the various typical industries were also tested and analyzed in the paper. The research did in the paper made a scientific basis for controlling heavy metal emissions from typical industries.
Authors: Woo Teck Kwon, Soo Ryong Kim, Y. Kim, Jong Hee Hwang, Vikram V. Dabhade, Tae Wook Yoo, Seong Youl Bae
Abstract: The possible utilization of automobile shredder residue as a fuel in the cement kiln process was investigated. The detailed characteristics of the automobile shredder residues were investigated in terms of it’s chlorine content as a fuel feed and its circulation in cement kiln. For estimation of the chlorine content in the cement kiln system, the Weber model which is one of the circulation material’s forecast model was used. From the results, we estimated the chlorine by-pass rate should be 1 ~ 2 percent, for maintaining the present level of chlorine content’s on the hot-meal of the cement kiln system.
Authors: Rui Cui Liu, Fu Yi Jiang, Zi Quan Liu
Abstract: Abstract:The article first described all kinds of pollution produced in the cement production line, mainly include air pollution, dust pollution, noise pollution and so on。Then the author stressed the physical and chemical characteristics of the produce of NOX in waste gas and the prevention and emissions reduction. Furthermore, the paper made a analysis of NOX emissions standards and pollution in current domestic and foreign cement plant, and give a few NOX removal and recovery technology at home and abroad. Among them,the article expounded the principles, process and application status of the reduction of ammonia nitrogen removal, and give it a simple evaluation.
Authors: Yu Yen Cheng, Mei Fang Lu, Jim Jui Min Lin
Abstract: While conducting research for dioxin emission factor for stationary source emission, it is found that some factors come from overestimation. The cause of discrepancy for estimating process comes often from lacking understanding of the process. The result of this study for secondary aluminum refining emission factors indicates that if raw materials are scraps, the factors averaged at 541 ng I-TEQ/Ton-raw materials. If waste aluminum is used as the raw material, factors averaged at 1338 ng I-TEQ/Ton-raw material. The factors based on site sampling for coal-fired power generation process is 24.84-549.62 ng I-TEQ/Ton-fuel. It varies according to coal sources. Emission factor for cement producing process is 95.4-102.66 ng I-TEQ/Ton-raw material. Due to fewer differences in operating traits, raw materials and fuel application for cement producing process, emission factors have smaller differences. The reliability for emission variables is relatively higher.
Authors: Hui Fang Zhang, Hong Liang Huang, Li Fang Zhang, Na Zheng, Fei Zhao
Abstract: 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.
Authors: Wijesinghe Kaluarachchige Hiromi Ariyaratne, Edirisinghe Vidana Pathiranage Jagath Manjula, Morten Christian Melaaen, Lars André Tokheim
Abstract: Increased use of alternative fuels in cement kilns is a trend in the world. However, replacing fossil fuels like coal with different alternative fuels will give various impacts on the overall kiln process due to the fuel characteristics. Hence, it is important to know to what extent the fossil fuels can be replaced by different alternative fuels without severely changing process conditions, product quality or emissions. In the present study, a mass and energy balance for the combustion of different alternative fuels in a cement rotary kiln was developed. First, the impact of different fuel characteristics on kiln gas temperature, kiln gas flow rate and air requirement were observed by using coal (reference case), meat and bone meal (MBM), two different wood types, refuse derived fuel and a mixture of saw dust and solid hazardous waste as the primary fuel. It was found that the key process parameters depend largely on the chemical characteristics of the fuel. It appears that MBM shows quite different results from other alternative fuels investigated. Next, simulation of combustion of a mixture of coal and MBM in the main burner was carried out in three steps. The first step was combustion of replacing part of coal energy with MBM, and a reduction in kiln exhaust gas temperature compared to the coal reference case was found. In the second step, the fuel feed rate was increased in order to raise the kiln gas temperature to that of the reference case. In the third step, the fuel feed rate and the clinker production rate were changed in order to have not only the same kiln gas temperature but also to obtain the same volumetric flow rate of total exhaust gas from the precalciner as in the reference case. Around 7% of reduction in clinker production rate could be observed when replacing 48% of the coal energy input. Results from a full-scale test using the same mixture of coal and MBM verified the simulation results.
Authors: Hai Bing Liu, Xiao Dong Chen, Jun Gu
Abstract: 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).
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