Lime is an important flux used in the iron and steel-making processes. Tata Steel Jamshedpur uses a twin-shaft Parallel Flow Regenerative type kiln to calcine limestone. Previously, the kiln was operated based on the temperature measurement at only three locations. This led to suboptimal kiln performance and difficulty in maintaining lime quality. A thermal digital twin was developed using first principles to address these issues. A set of unsteady-state partial-differential equations representing the thermophysical phenomena is solved numerically using the finite volume method. The model was validated with the measured flue gas temperature and lime temperatures. The model is implemented online with the real-time operating parameters to estimate the temperature profile of solid and gas and the degree of conversion of limestone. This real-time visibility enables the operators to optimize the process and achieve lime conversion up to 94%, resulting in energy savings of 31.8 GJ/day and stable lime quality.
AbhalePB, NagS, BapatY, KulkarniA, ViswanathanNN, Padmapal. 2022a. Development of 2D steady-state mathematical model for blast furnace using OpenFOAM®. Metall Mater Trans B. 53:3469–3491.
2.
AbhalePB, ViswanathanNN, HenrikS.2022b. Numerical modelling of blast furnace evolution and recent trends. Min Proc Extractive Metall. 129(2):166–183.
3.
AguiarB, VakkilainenE, CardosoM, CostaF.Jr.2017. The modelling and dynamic simulation of lime kiln. International Chemical Recovery Conference. Halifax, Nova Scotia.
4.
Arİ, DoğuG.2001. Calcination kinetics of high purity limestones. Chem Eng J. 83:131–137.
5.
BalakrishnanA, PeiD.1979. Heat transfer in gas-solid packed bed systems. 3. Overall heat transfer rates in adiabatic beds. Ind Eng Chem Process Design Dev. 18:47–50.
6.
BalakrishnanR, PeiD.1978. Convective heat transfer in gas–solid suspension flow through packed beds. AIChE J. 24:613–619.
7.
BarinI, KnackeO.1973. Thermochemical properties of inorganic substances. Berlin: Springer-Verlag.
8.
BesA.2006. Dynamic process simulation of limestone calcination in normal shaft kilns [PhD thesis]. Otto von Guericke University Magdeburg.
9.
BirdR, StewartW, LightfootE.1960. Transport phenomena. New York: John Wiley and Sons.
10.
BorgwardtR.1985. Calcination kinetics and surface area of dispersed limestone particles. AIChE J. 31:103–111.
11.
CoatsA, RedfernJ.1964. Kinetic parameters from thermogravimetric data. Nature. 201:68–69.
12.
CollariniO.2009. Innovative design of high-capacity twin shaft regenerative lime kilns. Cem Int J. 7:38–42.
13.
CrumpL.2000. Lime production: industry profile. U.S. Environmental Protection Agency. Project No. 7647-001-020.
14.
Fedunik-HofmanL, BayonA, DonneS.2019a. Comparative kinetic analysis of CaCO3/CaO reaction system for energy storage and carbon capture. Appl Sci. 9:4601.
15.
Fedunik-HofmanL, BayonA, DonneS.2019b. Kinetics of solid-gas reactions and their application to carbonate looping systems. Energies. 12:2981.
16.
FengK, LombardoS.2002. Kinetic analysis from dilatometry and mass spectrometry measurements of the decomposition and sintering of calcium carbonate. J Ceram Process Res. 3:101–108.
17.
GaskellD.2003. Introduction to the thermodynamics of materials. 4th ed. New York: Taylor & Francis.
18.
Hai-DoD.2012. Simulation of lime calcination in normal shaft and parallel flow regenerative kilns [PhD thesis]. Otto von Guericke University Magdeburg.
19.
HillsD.1968. The mechanism of the thermal decomposition of calcium carbonate. Chem Eng Sci. 23:297–320.
20.
KarhelaT.1996. Dynamic simulation model of rotary lime kiln [MSc thesis]. Tampere: Tampere University of Technology.
21.
LundbergT, OrreJ, PaananenT, MattilaO.2020. Modelling of the lime kiln at SSAB, Raahe. Proc SIMS. 61:153–159.
22.
MaitraS, ChakrabartyN, PramanikJ.2008. Decomposition kinetics of alkaline earth carbonates by integral approximation method. Ceramica. 54:268–272.
23.
ManochaS, PonchonF.2018. Management of lime in steel. Metals (Basel). 8:686.
24.
MillsA.1999. Basic heat and mass transfer. 2nd ed. Hoboken (NJ): Prentice Hall.
25.
ObstH, StradtmanJ.1972. The influence of lime and synthetic lime products on steel production. Afr Inst Min Metall. 72:158–164.
26.
PiringerH.2017. Lime shaft kilns. Energy Procedia. 120:75–95.
27.
RanzW, MarshalW.1952. Evaporation from drops: part 2. Chem Eng Prog. 48:173–180.
28.
SchramaF, BeunderE, Van Den BergB, YangY, BoomR.2017. Sulphur removal in ironmaking and oxygen steelmaking. Ironmak Steelmak. 44:333–343.
29.
SenegačnikA, OmanJ, ŠirokB.2007a. Analysis of calcination parameters and the temperature profile in an annular shaft kiln. Part 1: theoretical survey. Appl Therm Eng. 27:1467–1472.
30.
SenegačnikA, OmanJ, ŠirokB.2007b. Analysis of calcination parameters and the temperature profile in an annular shaft kiln. Part 2: results of tests. Appl Therm Eng. 27:1473–1482.
31.
ShagapovS, BurkinM.2008. Theoretical modeling of simultaneous processes of coke burning and limestone decomposition in a furnace. Combust Explos Shock Waves. 44:55–63.
32.
UmadeviT, BandopadhyayU, MahapatraP, PrabhuM, RanjanM.2010. Influence of limestone particle size on iron ore sinter properties and productivity. Steel Research int. 81:419–425.
33.
WakaoN.1976. Particle-to-fluid transfer coefficients and fluid diffusivities at low flow rate in packed beds. Chem Eng Sci. 31:1115–1122.
34.
WakaoN, KagueiS, FunazkriT.1979. Effect of fluid dispersion coefficients on particle-to-fluid heat transfer coefficients in packed beds: correlation of Nusselt numbers. Chem Eng Sci. 34:325–336.
35.
WonchalaEP, WynnyckyjJR.1987. The phenomenon of thermal channelling in counter-current gas-solid heat exchangers. Can J Chem Eng. 65:736–743.
36.
YiZ, ZhouJ, ChenH.2005. Numerical simulation of thermal process and energy saving of lime furnace. J Cent South Univ f Technol. 12:295–299.
