Showing papers on "Rotary kiln published in 2016"
TL;DR: The influence of process conditions (rotary speed/temperature) on the performance of a rotary kiln reactor for non-catalytic pyrolysis of a perennial grass was investigated and a H2/CO ratio suitable for Fischer-Tropsch synthesis (FTS) was obtained.
65 citations
TL;DR: The results of a simple mixing test revealed that the observed transformation of hazardous MSWI fly ash into non-hazardous bottom ash during thermal co-treatment cannot be referred to dilution, as the mixture did not comply with legal limits for non- hazardous waste landfills.
50 citations
TL;DR: In this paper, waste tire is pyrolyzed in a rotary kiln reactor to obtain more gas, light liquid, heavy liquid, wax products, and less carbon black at their maximum yields as, 20, 12, 25, 8% and 35% of the total weight (4Âtones), respectively.
46 citations
TL;DR: In this article, an energy saving strategy with two energy saving measures has been proposed for reducing energy loss in the rotary kiln-electric furnace (RKEF) for the smelting of ferronickel alloy.
44 citations
TL;DR: Experimental results using real datasets demonstrate that the proposed image-based systems for recognizing the temperature condition are effective and robust.
Abstract: Maintaining a normal burning temperature is essential to ensuring the quality of nonferrous metals and cement clinker in a rotary kiln. Recognition of the temperature condition is an important component of a temperature control system. Because of the interference of smoke and dust in the kiln, the temperature of the burning zone is difficult to be measured accurately using traditional methods. Focusing on blurry images from which only the flame region can be segmented, an image recognition system for the detection of the temperature condition in a rotary kiln is presented. First, the flame region is segmented employing a region-growing method with a dynamic seed point. Seven features, comprising three luminous features and four dynamic features, are then extracted from the flame region. Dynamic features constructed from luminous feature sequences are proposed to overcome the problem of mis-recognition when the temperature of the flame region changes rapidly. Finally, classifiers are trained to recognize the temperature state of the burning zone using its features. Experimental results using real datasets demonstrate that the proposed image-based systems for recognizing the temperature condition are effective and robust.
43 citations
TL;DR: In this paper, a pilot-scale trial was undertaken in a 7·4m kiln to demonstrate the production of belite calcium sulfoaluminate cement clinker using sulfur as a raw feed.
Abstract: A pilot-scale trial was undertaken in a 7·4 m kiln to demonstrate the production of belite calcium sulfoaluminate cement clinker using sulfur as a raw feed. The sulfur was introduced in its elemental form as fuel to the burner, thus partially offsetting fuel costs while providing sulfur trioxide which is incorporated in the clinker. The study demonstrates that sulfur trioxide is readily sequestered into cement clinker in a standard rotary kiln; however, some scrubbing of the exit gas may still be required. As the products of scrubbing (anhydrite or gypsum) are usually required to optimise the cement formulation, the recovered sulfur product can find an immediate use in the final cement product. This trial demonstrates the successful production of targeted belite calcium sulfoaluminate clinkers at scale using sulfur as both a fuel and sulfur trioxide source.
40 citations
TL;DR: In this article, a two-fluid approach and diverse heat transfer models are applied to a 2D cross-section of a rotary kiln coupled with granular flow kinetic theory, which treats random granular motion as thermal molecular motion.
32 citations
TL;DR: This research examines the safe treatment of waste TNT, RDX and Composition B in a rotary kiln type incinerator with regard to suitable operating conditions and concluded that waste explosives subject to heat supplied by hot air at 523.15K were incinerated safely without any thermal detonation.
30 citations
TL;DR: Simulation results indicate the proposed multi-model fusion soft sensor modelling method has a high learning speed, good approximation and generalization ability, and proved an efficient modelling method.
Abstract: A soft sensor is necessary for industrial process control and analysis, and the core problem is how to construct an appropriate model having a fast convergence speed and a good generalization perfo...
30 citations
TL;DR: In this paper, a rotary kiln type biomass gasification process was proposed based on air staging and process separation, which demonstrated that a fuel gas with high heat value of about 5500 kJ/Nm3 and gas production rate of 2.32 Nm3/kg could be produced.
Abstract: Tar formation is the main bottleneck for biomass gasification technology. A novel rotary kiln type biomass gasification process was proposed. The concept design was based on air staging and process separation. This concept was demonstrated on a pilot scale rotary kiln reactor under ambient pressure and autothermic conditions. The pilot scale gasifier was divided into three different reaction regions, which were oxidative degradation, partial oxidation and char gasification. A series of tests was conducted to investigate the effect of key parameters. The results indicate that under optimum operating conditions, a fuel gas with high heat value of about 5500 kJ/Nm3 and gas production rate of 2.32 Nm3/kg could be produced. Tar concentration in the fuel gas could be reduced to 108 mg/Nm3 (at the gasifier outlet) and 38 mg/Nm3 (after gas conditioning). The cold gas efficiency and carbon conversion rate reached 75% and 78%, respectively. The performance of this gasification system shows considerable potential for implementation in distributed electricity and heat supply projects.
27 citations
TL;DR: In order to improve the control performance of burning zone temperature in lime rotary kiln, a predictive control method based on improved hierarchical genetic algorithm and T-S fuzzy neural network was proposed.
Abstract: How to control burning zone temperature of the lime rotary kiln is an important problem. In order to improve the control performance of burning zone temperature in lime rotary kiln, a predictive control method based on improved hierarchical genetic algorithm and T-S fuzzy neural network was proposed. This control method utilised T-S fuzzy neural network to build a nonlinear predictive model of burning zone temperature in rotary kiln. The predictive error is corrected through predictive output burning temperature, output feedback error and error correction. A fitness function is established by deviation and control variable. An improved hierarchical genetic algorithm was used for rolling optimisation of the optimal control variable. Simulation results show that the proposed predictive method has good control effect.
TL;DR: In this article, thermal energy analysis of three zones of a lime production process, which are preheater, rotary kiln and cooler, is performed, in order to perform a proper quantitative estimation, the system was modeled using energy balance equations including coupled heat transfer and chemical reaction mechanisms.
TL;DR: In this paper, coal gangue was sintered in a rotary kiln to form lightweight aggregates and the results showed that the optimum mixture ratio of coal gangues, shale, and sludge is 50, 40, and 10 wt% and the corresponding indicators of aggregates obtained are: (a) bulk density of 658 kg/m3, (b) granule strength of 643N, (c) 1 h absorption water to be 13.8%.
Abstract: Coal gangue has accumulated huge coal gangue piles, occupying lots of land as well as having striking influence on the neighboring environmental effects. This paper seeks a new way of coal gangue treatment in which the coal gangue blended with shale and sludge was sintered in rotary kiln to form lightweight aggregates. The results show that the optimum mixture ratio of coal gangue, shale, and sludge is 50, 40, and 10 wt% and the corresponding indicators of aggregates obtained are: (a) bulk density of 658 kg/m3, (b) granule strength of 643N, (c) 1 h absorption water to be 13.8%.
TL;DR: In this paper, a comprehensive wear mechanism was elaborated that includes the impact of bottom ash characteristics at operating temperatures, and experimental based guidelines were provided that may help operators extend the lifetime of the refractory bricks and reduce maintenance cost significantly.
TL;DR: In this paper, a simplified model of a rotary kiln and a new methodology for studying stability of the lining is suggested, and the behaviour of the linings in cold state and dynamic cases is studied.
TL;DR: In this paper, up-scaling tracer experiments were carried out in a pilot-scale rotary kiln twice as big as the kiln used in the first two Parts of this study.
TL;DR: In this article, the authors developed a one-dimensional rotary kiln model using elements of existing models and then linked the model to the surroundings via a composite resistance model and a forced convection model that enables proper inclusion of the effects of shell-cooling fans.
TL;DR: Wang et al. as mentioned in this paper proposed a nonlinear cubic polynomial fitting temperature compensation algorithm to compensate the temperature values of scanning points on rotary kiln surface by following steps: Calculating temperature difference between the real temperature value of rotary Kiln and temperature value measured by infrared scanning temperature measurement system; Fitting the temperature difference data with cubic Polynomial; Using the obtained function to compensate temperature.
TL;DR: In this article, the incineration process of polychlorinated biphenyls (PCBs) wastes in a rotary kiln is governed by a dynamic model consisting of a set of nine stiff nonlinear equations.
Abstract: 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.
TL;DR: In this article, a new approach to the direct conversion of lignites by heterogeneous catalysis under pyrolytic conditions and without additional hydrogenation was proposed, and the results were confirmed at a semi-technical scale rotary kiln.
TL;DR: In this article, an exergoeconomic analysis of the rotary kiln used for plaster production was carried out by using actual operational data to see its effectiveness, the exergy cost is 593.6 US$/h and the cost per unit exergy is 1502.4US$/GJ of the Calcium sulfate hemihydrate or plaster produced by the system.
Patent•
15 Jun 2016
TL;DR: In this paper, a semicoke cooling system consisting of a primary cooling device and a secondary cooling device is presented, where the primary cooling system comprises a heater exchanger, the heat exchanger is arranged below a rotary kiln and is communicated with the rotary Kiln.
Abstract: The invention provides a semicoke cooling system. The semicoke cooling system comprises a primary cooling device and a secondary cooling device, wherein the primary cooling device comprises a heater exchanger, the heat exchanger is arranged below a rotary kiln and is communicated with the rotary kiln; and the secondary cooling device comprises a cooling screw conveyor, and the cooling screw conveyor is communicated with the primary cooling device. The primary cooling device containing the heat exchanger is arranged below the rotary kiln, so that high temperature power equipment between the rotary kiln and a high temperature heat exchanger is eliminated, equipment failure caused by high temperature is avoided, equipment running stability is improved, and semicoke produced by the rotary kiln can conveniently directly fall into the heat exchanger by virtue of gravity to be subjected to primary cooling; then the semicoke is further subjected to secondary cooling by virtue of the cooling screw conveyor, and a semicoke material fully rolls in a material pipe under the action of a screw conveying shaft and is fully contacted with a cooling surface, so that final coke discharging temperature is consistent, and further quality of the cooled semicoke product is improved.
TL;DR: In this article, the unburned carbon in bagasse ash was separated and used as a starting material for activated carbon and carbon monolith preparation, and the separated carbon was steam activated in a rotary kiln.
Abstract: The unburned carbon in bagasse ash was separated and used as a starting material for activated carbon and carbon monolith preparation. The separated carbon was steam activated in a rotary kiln unde ...
Patent•
12 Oct 2016
TL;DR: In this article, a process for extracting iron from comprehensive tailings of refractory iron ores comprises the following main steps: after drying and scattering the comprehensive tailsings of the refractories of the ores, magnetically separating them by using a dry type low-intensity magnetic separation machine to obtain magnetic tailings and non-magnetic tailings; and carrying out size grading on the magnetic tailsings with low coarse fraction grade and high SiO2 content.
Abstract: A process for extracting iron from comprehensive tailings of refractory iron ores comprises the following main steps: after drying and scattering the comprehensive tailings of the refractory iron ores, magnetically separating the comprehensive tailings of the refractory iron ores by using a dry type low-intensity magnetic separation machine to obtain magnetic tailings and non-magnetic tailings; and carrying out size grading on the magnetic tailings to remove the magnetic tailings with low coarse fraction grade and high SiO2 content; carrying out three-stage low-intensity magnetic separation and desilicification to increase iron grade so as to obtain qualified iron ore concentrates; granulating and drying the non-magnetic tailings at first, and then mixing the non-magnetic tailings with a pulverized coal reducing agent; loading in a rotary kiln in a mixed manner and magnetically roasting, wherein roasting temperature is 700-850 DEG C and high-temperature roasting time is 30-50 min; after roasting is finished, cooling to the temperature below 100 DEG C by using an indirect water-cooling mode; and then carrying one-stage grinding and two-stage magnetic separation to obtain qualified iron core concentrates finally. Compared with the traditional tailings treatment method, the process is purposeful, the comprehensive tailings are classified according to different properties of the comprehensive tailings, the tailings treatment efficiency can be improved, so that useful resources are extracted to a maximum extent, and the tailings of the refractory iron ores are utilized comprehensively.
TL;DR: In this paper, the effects of variations of input parameters, such as angle of inclination, number of rotation and mass flow rate of iron ore are studied on output parameters like Fe content, temperature profile.
Abstract: The present paper deals with 2D CFD model of sponge iron rotary kilns. Using this model the effects of variations of input parameters, such as angle of inclination, number of rotation and mass flow rate of iron ore are studied on output parameters like Fe content, temperature profile. These ranges of input parameters are found from industrial practice. For this purpose different models of CFD such as Species transport model, k-epsilon viscous model, Discrete Ordinates (DO) and P1 model, and finite rate/eddy dissipation model are used to find Fe content, temperature profiles. The results of the 2D CFD model show that optimum angle is found as 2.8°. The optimum number of rotation and flow rate of iron ore is found as 4.7 and 5.83 kg/s, respectively. At these optimum conditions the Fe content is predicted as 92%, which is 4.5% more in comparison to existing system that is being operated at angle of inclination, number of rotation and mass flow rate of iron ore as 2.5°, 4.3 rpm and 5.83 kg/s, respectively. The temperature profiles of gas and bed are also found within acceptable temperature limits. The results are compared well with the published work.
TL;DR: In this article, a 2D axisymmetric model is applied to study the effect of both operating and geometric parameters of rotary kiln on the characteristics of the flame length.
Abstract: Numerical simulations using computational fluid dynamics (CFD) are performed to investigate the flame length characteristics in rotary kilns using probability density function (PDF) approach. A commercial CFD package (ANSYS-Fluent) is employed for this objective. A 2-D axisymmetric model is applied to study the effect of both operating and geometric parameters of rotary kiln on the characteristics of the flame length. Three types of gaseous fuel are used in the present work; methane (CH4), carbon monoxide (CO) and biogas (50 % CH4 + 50 % CO2). Preliminary comparison study of 2-D modeling outputs of free jet flames with available experimental data is carried out to choose and validate the proper turbulence model for the present numerical simulations. The results showed that the excess air number, diameter of kiln air entrance, radiation modeling consideration and fuel type have remarkable effects on the flame length characteristics. Numerical correlations for the rotary kiln flame length are presented in terms of the studied kiln operating and geometric parameters within acceptable error.
Patent•
29 Jun 2016
TL;DR: In this article, a system treatment method for the oil field oily sludge is characterized by comprising the steps that the sludge are filtered first, large materials filtered out are fed into a rotary kiln to be incinerated, and other materials are conveyed to a drying table to be dried; meanwhile, oil water is collected, the dried sludge was fed into the rotary Kiln to incinerated to be inorganic; gas generated by incineration entered a secondary combustion chamber to further thoroughly incinerated; heat generated by burning water in a boiler, the hot water flows to
Abstract: Provided is a system treatment method for oil field oily sludge. The system treatment method aims to conduct thorough harmless disposal on oily sludge produced by an oil field and is used for solving the problems that the oiliness of discharged oily sludge exceeds the standard and the operation cost is high. The system treatment method for the oil field oily sludge is characterized by comprising the steps that the sludge is filtered first; large materials filtered out are fed into a rotary kiln to be incinerated, and other materials are conveyed to a drying table to be dried; meanwhile, oil water is collected; the dried sludge is fed into the rotary kiln to be incinerated to be inorganic; gas generated by incineration enters a secondary combustion chamber to be further thoroughly incinerated; heat generated by incineration is used for heating water in a boiler; the hot water flows to the drying table along a pipeline to heat the sludge; cooled water flows back into the boiler; saltpetre contained in the generated flue gas is processed by an SCR/SNCR process, the boiler flue gas enters an absorption tower, and generated sulfur is absorbed; and the flue gas continues to enter a wet electrostatic dust collector to be subjected to dust treatment and then is discharged.
TL;DR: In this article, the results showed that a ferronickel containing 10.32 wt. % Ni was obtained from a laterite with 1.85 wt % Ni, the nickel recovery ratio was about 99%.
Abstract: Nickel is an important strategic metal, which is mainly used for stainless steel production. In the recent years, ferronickel has been used as a substitute for electrolytic nickel for alleviating the cost of stainless steel production. Rotary kiln-electric furnace (RKEF) smelting is currently the world-wide mainstreaming process for ferronickel production from nickeliferous laterite ore, in spite of the high power consumption. In this study, aiming to provide some meaningful guidance for ferronickel production of RKEF smelting, reductive roasting followed by smelting process was carried out. The conditions including reducing parameters (roasting temperature and time) and smelting parameters (coke dosage, CaO dosage, melting temperature and time) were ascertained. The metal recovery ratios, as well as Ni, Fe, S and P content of ferronickel were considered. The results showed that a ferronickel containing 10. 32 wt. % Ni was obtained from a laterite with 1. 85 wt. % Ni, the nickel recovery ratio was about 99%.
TL;DR: Zhu et al. as discussed by the authors developed an effective way to utilize siderite resource, which is refractory to beneficiate and has hardly been employed in iron production mainly due to its characterization that higher loss on ignition (LOI), low iron grade, decompositions of carbonate, and a significant amount of substitutions of Mg, Ca and Mn for Fe in isomorphism in the sidersite lattice.
Abstract: With the extensive mining of high grade iron ore resources, the average iron grade of minable iron ore reserves is only about 30% in China. Low grade ore is available abundantly, but it is used ineffectively due to the difficulties in ore preparations. As one of important iron ore resources, siderite ore is abundant in China with proven reserve of 1.83 billion tons, occupying 14% of total iron ore reserves.1,2) However, siderite is refractory to beneficiate and has hardly been employed in iron production mainly due to its characterization that higher loss on ignition (LOI), low iron grade, decompositions of carbonate, and a significant amount of substitutions of Mg, Ca and Mn for Fe in isomorphism in the siderite lattice. The high grade siderite directly used for ironmaking is less than 10% of its total reserves.3) Since siderite is difficult to upgrade by traditional beneficiation technologies, such as flotation, gravity separation, magnetic separation or the combinative processes of these technologies, it is urgent to develop of an effective way to utilize siderite resource. In recent years, extensive researches have been focused on pyrometallurgical processes and such as magnetizing roasting-magnetic separation and direct reduction-magnetic separation process.3–9) For DRI production process of siderite, Zhu6) Coproduction of DRI Powder and Semi-coke from Siderite Ore and Low Rank Coal by Excessive Coal-based Direct Reduction in Rotary Kiln