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.

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.

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.

Computer Simulation of Heat Transfer in a Rotary Lime Kiln

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Ashish Agrawal ◽  
P. S. Ghoshdastidar
Keyword(s):  
Heat Transfer ◽  
Rotary Kiln ◽  
Wall Temperature ◽  
Gas Temperature ◽  
Gas Radiation ◽  
Temperature Distributions ◽  
Refractory Wall ◽  
Radiation Heat Exchange ◽  
Shrinking Core ◽  
Energy Balances

In the present work, a steady-state, finite difference-based computer model of heat transfer during production of lime in a rotary kiln has been developed. The model simulates calcination reaction in the solid bed region of the rotary kiln along with turbulent convection of gas, radiation heat exchange among hot gas, refractory wall and the solid surface, and conduction in the refractory wall. The solids flow countercurrent to the gas. The kiln is divided into axial segments of equal length. The mass and energy balances of the solid and gas in an axial segment are used to obtain solids and gas temperature at the exit of that segment. Thus, a marching type of solution proceeding from the solids inlet to solids outlet arises. To model the calcination of limestone, shrinking core model with surface reaction rate control has been used. The output data consist of the refractory wall temperature distributions, axial solids and gas temperature distributions, axial percent calcination profile, and kiln length. The kiln length predicted by the present model is 5.74 m as compared to 5.5 m of the pilot kiln used in the experimental study of Watkinson and Brimacombe (1982, Watkinson, A.P. and Brimacombe, J. K., “Limestone Calcination in a Rotary Kiln,” Metallurgical Transactions B, Vol. 13B, pp. 369–378). The other outputs have been also satisfactorily validated with the aforementioned experimental results. A detailed parametric study lent a good physical insight into the lime making process and the kiln wall temperature distributions.

A Computational Heat Transfer and Optimization Study of Drying of Peas and Rice in a Rotary Dryer

2019 ◽  
Author(s):  
Atinder Pal Singh ◽  
P. S. Ghoshdastidar
Keyword(s):  
Heat Transfer ◽  
Superheated Steam ◽  
Gas Temperature ◽  
Initial Water ◽  
Dry Air ◽  
Rice Grains ◽  
Refractory Wall ◽  
Optimization Study ◽  
Rotary Dryer ◽  
Inner Diameter

Abstract The paper reports a numerical simulation study of drying of peas and rice grains in a rotary dryer with superheated steam, dry air, and humid air (20%, 40%, 60% and 80% moisture content by volume) at 1 bar as the drying media. The initial water contents in peas and rice grains are 75% and 13% (by weight), respectively. The thermal model includes turbulent convection heat transfer from the gas to the refractory wall and solids, radiation exchange among the gas, refractory wall and the solid surface, conduction in the refractory wall, and mass and energy balances of the gas and the solids. In the absence of experimental data of food drying, the present model has been satisfactorily validated with the experimental and numerical results reported in Sass (1967, Sass, A., “Simulation of Heat-Transfer Phenomena in a Rotary Kiln”, Industrial & Engineering Chemistry Process Design and Development, 6(4), pp. 532–535) for iron ore and cement. It is found that for superheated steam there is an optimum kiln inner diameter at which the predicted kiln length is the highest. For dry air, the predicted kiln length monotonically decreases with a decrease in kiln inner diameter. A detailed parametric study lent a good physical insight into the drying process. An optimization study has been conducted for superheated steam as the drying medium using the Univariate Search method to minimize the length of the kiln with an upper limit on the inlet gas temperature as the constraint.

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.

Computational Analysis of Gas Flow and Heat Transport Phenomena in Monolithic Structures for High Temperature Processes

2005 ◽  
Author(s):  
Faruk Selimovic ◽  
Tor Bruun ◽  
Bengt Sunde´n
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Power Density ◽  
Gas Flow ◽  
Gas Temperature ◽  
Oxidation Of Methane ◽  
Steam Methane ◽  
High Temperature Processes ◽  
Efficient Heat Transfer ◽  
Flow Maldistribution

High-temperature catalytic processes such as partial oxidation of Methane (POX) and steam Methane reforming (SMR) may benefit from use of reactor systems using monolithic honeycomb structures. Hereby, process performance is enhanced through more efficient heat transfer and considerable smaller reactor foot-prints than for conventional reactor concepts. Compact ceramic heat exchange structures may also be an interesting option for increasing the energy efficiency of high temperature processes in general. One example is single cycle turbines where these structures can be used as recuperators. The purpose of this paper is to describe modelling of gas flow pattern and heat transfer in reactors and heat exchangers with monolithic based structures. This technology is currently under development in a partnership of European companies and academia, with financial support from the EC and Swiss Government. The mathematical model developed for heat transfer and flow maldistribution has been used for counter-current checkerboard channel-arrangement. Pressure drop has been analyzed both experimentally and numerically (computation fluid dynamics, CFD). Power density has been shown to depend on various reactor parameters. Channel geometry, inlet gas temperature difference and channel wall thickness have been calculated to find the influence on power density.

COMPUTER SIMULATION OF HEAT TRANSFER DURING DRYING AND PREHEATING OF WET IRON ORE IN A ROTARY KILN

2002 ◽  
Vol 20 (1) ◽  
pp. 19-35 ◽  
Author(s):  
P. S. Ghoshdastidar ◽  
G. Bhargava ◽  
R. P. Chhabra
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
Rotary Kiln ◽  
Iron Ore
Sign in / Sign up

Export Citation Format

Share Document