Computer Simulation of Drying of Food Products With Superheated Steam in a Rotary Kiln

2010 ◽  
Author(s):  
Koustubh Sinhal ◽  
P. S. Ghoshdastidar ◽  
Bhaskar Dasgupta
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
Flow Rate ◽  
Rotary Kiln ◽  
Rotational Speed ◽  
Gas Flow ◽  
Superheated Steam ◽  
Gas Temperature ◽  
Gas Flow Rate ◽  
Refractory Wall

The present work reports a computer simulation study of heat transfer in a rotary kiln used for drying and preheating food products such as fruits and vegetables with superheated steam at 1 bar. The heat transfer model includes radiation exchange among the superheated steam, refractory wall and the solid surface, conduction in the refractory wall, and the mass and energy balances of the steam and solids. Finite-difference techniques are used, and the steady state thermal conditions are assumed. The false transient approach is used to solve the wall conduction equation. The solution is initiated at the inlet of the kiln, and proceeds to the exit. The output data consist of distributions of the refractory wall temperature, solid temperature, steam temperature, and the total kiln length. The inlet of the kiln is the outlet of the gas (superheated steam), since the gas flow is countercurrent to the solid. Thus, for a fixed solid and gas temperature at the kiln inlet, the program predicts the inlet temperature of the gas (i.e. at the kiln exit) in order to achieve the specified exit temperature. In the absence of experimental results for food drying in a rotary kiln, the present model has been satisfactorily validated against numerical results of Sass [1] for drying of wet iron ore in a rotary kiln. The results are presented for drying of apple and carrot pieces. A detailed parametric study indicates that the influence of controlling parameters such as percent water content (with respect to dry solids), solids flow rate, gas flow rate, kiln inclination angle and the rotational speed of the kiln on the axial solids and gas temperature profiles and the total predicted kiln length is appreciable. The study reveals that a good design of a rotary kiln requires medium gas flow rate, small angle of inclination and low rotational speed of the kiln.

Computer Simulation of Drying of Food Products With Superheated Steam in a Rotary Kiln

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Koustubh Sinhal ◽  
P. S. Ghoshdastidar ◽  
Bhaskar Dasgupta
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
Flow Rate ◽  
Rotary Kiln ◽  
Gas Flow ◽  
Superheated Steam ◽  
Food Products ◽  
Gas Temperature ◽  
Refractory Wall ◽  
Solid Temperature

The present work reports a computer simulation study of heat transfer in a rotary kiln used for drying and preheating food products such as fruits and vegetables with superheated steam at 1 bar. The heat transfer model includes radiation exchange among the superheated steam, refractory wall and the solid surface, conduction in the refractory wall, and the mass and energy balances of the steam and solids. The gas convection is also considered. Finite-difference techniques are used, and the steady state thermal conditions are assumed. The false transient approach is used to solve the wall conduction equation. The solution is initiated at the inlet of the kiln and proceeds to the exit. The output data consist of distributions of the refractory wall temperature, solid temperature, steam temperature, and the total kiln length. The inlet of the kiln is the outlet of the gas (superheated steam), since the gas flow is countercurrent to the solid. Thus, for a fixed solid and gas temperature at the kiln inlet, the program predicts the inlet temperature of the gas (i.e., at the kiln exit) in order to achieve the specified exit temperature of the gas. In the absence of experimental results for food drying in a rotary kiln, the present model has been satisfactorily validated against numerical results of Sass (1967, “Simulation of the Heat-Transfer Phenomena in a Rotary Kiln,” Ind. Eng. Chem. Process Des. Dev., 6(4), pp. 532–535) and limited measured gas temperature as reported by Sass (1967, “Simulation of the Heat-Transfer Phenomena in a Rotary Kiln,” Ind. Eng. Chem. Process Des. Dev., 6(4), pp. 532–535) for drying of wet iron ore in a rotary kiln. The results are presented for drying of apple and carrot pieces. A detailed parametric study indicates that the influence of controlling parameters such as percent water content (with respect to dry solids), solids flow rate, gas flow rate, kiln inclination angle, and the rotational speed of the kiln on the axial solids and gas temperature profiles and the total predicted kiln length is appreciable. The effects of inlet solid temperature and exit gas temperature on the predicted kiln length for carrot drying are also shown in this paper.

Heat Transfer in the Non-reacting Zone of a Cement Rotary Kiln

1996 ◽  
Vol 118 (1) ◽  
pp. 169-172 ◽  
Author(s):  
P. S. Ghoshdastidar ◽  
V. K. Anandan Unni
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Rotary Kiln ◽  
Gas Flow ◽  
Transfer Model ◽  
Temperature Profiles ◽  
Gas Temperature ◽  
Gas Flow Rate ◽  
Steady State Heat ◽  
Steady State Heat Transfer

This paper presents a steady-state heat transfer model for a rotary kiln used for drying and preheating of wet solids with application to the non-reacting zone of a cement rotary kiln. A detailed parametric study indicates that the influence of the controlling parameters such as percent water content (with respect to dry solids), solids flow rate, gas flow rate, kiln inclination angle and the rotational speed of the kiln on the axial solids and gas temperature profiles and the total predicted kiln length is appreciable.

Simulation and Optimization of Drying of Wood Chips With Superheated Steam in a Rotary Kiln

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
P. S. Ghoshdastidar ◽  
Ankit Agarwal
Keyword(s):  
Heat Transfer ◽  
Rotary Kiln ◽  
Superheated Steam ◽  
Wood Chips ◽  
Transfer Model ◽  
Gas Temperature ◽  
Simulation And Optimization ◽  
Hot Gas ◽  
Refractory Wall ◽  
Optimization Study

The present work reports a computer simulation and optimization study of heat transfer in a rotary kiln used for drying and preheating wood chips with superheated steam at 1 bar. A rotary kiln employed for drying and preheating wet solids consists of a refractory lined cylindrical shell mounted at a slight incline from the horizontal plane. The kiln is slowly rotated about its longitudinal axis. Wet solids are fed into the upper end of the cylinder, and during the process, they are dried and heated by the counter-current flow of the hot gas. Finally, it is transferred to the lower end, where it reaches the desired temperature and is discharged. The heat transfer model includes radiation exchange among hot gas, refractory wall and the solid surface, transient conduction in the refractory wall, and mass and energy balances of the hot gas and solids. A finite-difference based computational heat transfer approach is used. A univariate search method has been used to obtain the minimum kiln length with respect to various kiln operating parameters subject to a constraint on the inlet gas temperature. The parametric study lent a good insight into the physics of the drying process in a rotary kiln. The optimization study reveals that for the same predicted kiln length, lower inlet steam temperature can be used, which will result in saving of energy cost.

Simulation and Optimization of Drying of Wood Chips With Superheated Steam in a Rotary Kiln

2008 ◽  
Author(s):  
P. S. Ghoshdastidar ◽  
Ankit Agarwal
Keyword(s):  
Heat Transfer ◽  
Rotary Kiln ◽  
Gas Flow ◽  
Superheated Steam ◽  
Wood Chips ◽  
Transfer Model ◽  
Simulation And Optimization ◽  
Hot Gas ◽  
Refractory Wall ◽  
Optimization Study

The present work reports a computer simulation and optimization study of heat transfer in a rotary kiln used for drying and preheating of wood chips with superheated steam at 1 bar. A rotary kiln employed for drying and preheating of wet solids consists of a refractory lined cylindrical shell mounted at a slight incline from the horizontal plane. The kiln is very slowly rotated about its longitudinal axis. Wet solids are fed into the upper end of the cylinder and during the process, are dried and heated by the countercurrent flow of the hot gas. Finally, it is transferred to the lower end where it reaches the desired temperature and discharged. The heat transfer model includes radiation exchange among hot gas, refractory wall and the solid surface, transient conduction in the refractory wall, and mass and energy balances of the hot gas and the solids. A finite-difference based computational heat transfer approach is used. A Univariate Search method has been used to obtain minimum kiln length with respect to various kiln operating parameters subject to a constraint on the inlet gas temperature. The parametric study lent a good insight into the physics of the drying process in a rotary kiln. The optimization study reveals that for an economical design of a rotary kiln low rotational speed, small inclination angle and medium gas flow rate is required.

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.

Wpływ warunków środowiskowych i instalacyjnych na proces wymiany ciepła w wybranych przemysłowych gazomierzach miechowych

Nafta-Gaz ◽  
2020 ◽  
Vol 76 (11) ◽  
pp. 828-836
Author(s):  
Adrian Dudek ◽  
Keyword(s):  
Heat Exchange ◽  
Ambient Temperature ◽  
Flow Rate ◽  
Gas Flow ◽  
Exchange Process ◽  
Test Results ◽  
Gas Temperature ◽  
Gas Flow Rate ◽  
Heat Exchange Process ◽  
The Relationship

Since 2016, Oil and Gas Institute – National Research Institute (INiG – PIB) has been conducting new research to determine the relationship between ambient temperature and gas temperature in industrial diaphragm gas meters during the measurement, and to develop new recommendations for billing systems using industrial diaphragm gas meters with a throughput of until 25 m3/h. In the first stage, work was carried out, in which the obtained test results confirmed that the heat exchange process in an industrial diaphragm gas meter depends on the ambient temperature, the gas temperature at the inlet to the gas meter, the flow rate of the gas flowing, as well as the casing surface and the gas volume of the gas meter. In the next stage, work was carried out to determine the relationship between ambient temperature and gas temperature at the industrial diaphragm gas meter connection during the measurement. The obtained results undermined the thesis, which indicated that the gas inlet temperature is equal to the gas temperature at the depth of the gas network. In the last stage, work was carried out to determine the course of changes in gas temperature in industrial diaphragm gas meters as a function of ambient temperature and cyclical changes of the gas flow rate, which were to reflect the work of gas meters installed at customers’ premises. The analysis of the obtained test results once again showed a strong dependence of the gas temperature inside industrial diaphragm gas meters on the ambient temperature, but also on the flow rate of gas. The obtained results of laboratory tests will be used to carry out a thermodynamic description of the heat exchange process in an industrial diaphragm gas meter, which would allow the determination of the gas billing temperature as a function of the ambient temperature, the temperature of the inflowing gas and the gas flow rate. The calculated gas temperature values could be used to determine the temperature correction factors applicable when settling gas consumers billed on the basis of measurement with the use of industrial diaphragm gas meters.

The Slip Factor of a Radial Bladed Centrifugal Compressor

1965 ◽  
Vol 87 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Alfred F. Stahler
Keyword(s):  
Flow Rate ◽  
Centrifugal Compressor ◽  
Rotational Speed ◽  
Gas Flow ◽  
Centrifugal Impeller ◽  
Gas Flow Rate ◽  
Slip Factor ◽  
Impeller Geometry

Several of the methods of explaining and evaluating the slip factor of a centrifugal impeller with straight radial blades are presented. The slip factors are calculated by these methods and compared to the experimentally observed characteristics of an impeller with 19 blades. It is shown that the slip factor depends on the gas-flow rate, the rotational speed, and the impeller-tip diameter. It is concluded that the slip-factor characteristics are better described by means of a constant leaving angle of the flow relative to the impeller and that the leaving angle is only a function of the impeller geometry.

scholarly journals Effects of Gas Flow on Spectral Properties of Plasma Jet Induced by Microwave

2018 ◽  
Vol 15 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Gas Flow ◽  
Microwave Plasma ◽  
Plasma Jet ◽  
Gas Temperature ◽  
Gas Flow Rate ◽  
Argon Gas ◽  
Jet Length ◽  
Maximum Value

In this paper, a construction microwave induced plasma jet(MIPJ) system was used to produce a non-thermal plasma jet at atmospheric pressure, at standard frequency of 2.45 GHz and microwave power of 800 W. The working gas Argon (Ar) was supplied to flow through the torch with adjustable flow rate using flow meter regulator. The influence of the MIPJ parameters such as applied voltage and argon gas flow rate on macroscopic microwave plasma parameters were studied. The macroscopic parameters results show increasing of microwave plasma jet length with increasing of applied voltage, argon gas flow rate where the plasma jet length exceed 12 cm as maximum value. While the increasing of argon gas flow rate will cause increasing into the argon gas temperature, where argon gas temperature the exceed 350 ? as maximum value and study the effect of gas flow rate on the optical properties

scholarly journals Exergy Analysis of Waste Incineration Plant: Flue Gas Recirculation and Process Optimization

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 29
Author(s):  
Giorgio Vilardi ◽  
Nicola Verdone
Keyword(s):  
Flow Rate ◽  
Flue Gas ◽  
Gas Flow ◽  
Exergy Analysis ◽  
Waste Incineration ◽  
Exergy Efficiency ◽  
Gas Temperature ◽  
Gas Flow Rate ◽  
Flue Gas Recirculation ◽  
Gas Recirculation

Simulations of two incineration processes, with and without flue gas recirculation, have been carried out performing an exergy analysis to investigate the most critical equipment unit in terms of second-law efficiency. Flue gas from the economizer outlet is employed to partially replace secondary combustion air to reduce, at the same time, incinerator temperature and oxygen concentration. Conversely, in the proposed configuration, the recirculated flue gas flow rate is used to control incinerator temperature, while the air flow rate is used to control the oxygen content of the fumes, leaving the incinerator as close to 6% as possible—i.e., the minimum allowed for existing plants to ensure completion of the combustion reactions and according to environmental regulations—and determines the corresponding minimum flue gas flow rate. The flue gas recirculation guarantees a larger level of energy recovery (up to +3%) and, at the same time, lower investment costs for the lower flow rate of fumes actually emitted if compared to the plant configuration without flue gas recirculation. Various operating parameters were varied (incinerator’s effluent gas temperature, air flowrate and flue gas recirculation flowrate) to investigate their influence on process exergy efficiency. Exergy analysis allowed the individuation of the equipment units characterized by larger exergy destruction and demonstrated that the flue gas recirculation led to an overall process exergy efficiency increase of about 3%.

Investigation of a Plasma Jet Generated by High Voltage Discharge at Atmospheric Pressure

2011 ◽  
Vol 383-390 ◽  
pp. 5907-5911 ◽  
Author(s):  
Xue Chen Li ◽  
Ning Yuan ◽  
Peng Ying Jia
Keyword(s):  
Flow Rate ◽  
High Voltage ◽  
Discharge Current ◽  
Applied Voltage ◽  
Atmospheric Pressure ◽  
Gas Flow ◽  
Plasma Plume ◽  
Gas Temperature ◽  
Gas Flow Rate ◽  
Uniform Plasma

Appling a high voltage to the dielectric barrier discharge device in a coaxial geometry in flowing argon, a uniform plasma plume is generated at one atmospheric pressure. The waveforms of discharge current and the applied voltage are investigated and results indicate that both the intensity and duration width of the discharge current pulse increase with increasing the applied voltage. The gas temperature of the plasma plume is investigated by using an infrared thermometer. The gas temperature of the plasma plume are functions of gas flow rate, peak value and the frequency of the applied voltage. Results show that the gas temperature increases with increasing the applied voltage or its frequency, while it decreases with increasing the gas flow rate. A qualitative explanation is given for the variance of gas temperature as functions of the experimental parameters by analyzing the waveforms of the discharge current and the applied voltage.

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