The paper presents an energetic and technologic analysis of the metallurgic coke dry cooling plant (CDCPO) operating, and also the optimization of this process in the case of an industrial plant, existing in the Steel Works S.A. Galati. The drawn–up analysis is based on the thermal balance of the industrial plant, in order to establish some mathematical equations that characterize the technological process

Adrian VASILIU

Gina NĂSTASE

Natalia BEGLET

Vasile MIREA

The Annals of “Dunarea de Jos” University of Galati Fascicle IX Metallurgy and Materials Science

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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI 
0FASCICLE IX METALLURGY AND MATERIALS SCIENCE, ISSN 1453 – 083X. N . 2 – 2006 
 
 
 
 
THE DECREASING OF THE ENERGETIC  
LOSSES AT A COKE DRY COOLING PLANT 
 
Adrian VASILIU1, Gina NĂSTASE1,  
Natalia BEGLET2, Vasile MIREA3 
1   Dunărea de Jos University of Galati,  
 2  Technical University of Moldavia” Kishinew, Moldova Republic 
3   „POLITEHNICA” University of Bucuresti  
e-mail: avasiliu@email.ro
 
ABSTRACT  
 
The paper presents an energetic and technologic analysis of the metallurgic coke 
dry cooling plant (CDCPO) operating, and also the optimization of this process in 
the case of an industrial plant, existing in the Steel Works S.A. Galati. The drawn–up 
analysis is based on the thermal balance of the industrial plant, in order to establish 
some mathematical equations that characterize the technological process. 
 
KEYWORDS: coke, thermal flux, recuperation boiler, mathematical model 
 
 
1. Introduction 
 
 
 The efficiently of (ISUC – Cooke Dry Cooling 
Plant) from “MITTAL STEEL SA” is made by using 
the thermal balance of this installation.  
 This means, that proper establish a 
mathematical model that characterize a good 
functionary for (ISUC) based on entrance system 
parameters. 
2. This installation is used on a coke 
cooling (I.S.U.C.) 
 
This installation is used on a coke cooling by 
using inert gases and warm recuperation with 
recuperation boiler. This plant has five blocks. Each 
block have: an extinction recipient, a recuperation 
boiler, a principally exhausting and systems for 
powder elimination and too a system for measuring 
and automation of functionary parameters (fig. 1). 
 
                       
 
Fig 1. Coke Dry Quenching Installation. 
 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI 
0FASCICLE IX METALLURGY AND MATERIALS SCIENCE, ISSN 1453 – 083X. N . 2 – 2006 
 
 
The extinction recipient has two compartments 
(extinction recipient and a room for warming cocks 
accumulation) and at the bottom an installation for 
gases distribution and a hole for cooling coke 
evacuation. At the top there are channels for gasses 
accumulated finishing with a hole for inert gases 
evacuation. The charging of warning coke in a 
mechanized operation on the top of installation and 
than is mode an hydraulic entrance opening. 
The inert gases are sender in continuous system 
throw inellary hole in layer of warning coke. At 
8000C this gases left the recipient and enter into 
recuperating boiler. The inert gases an evacuated 
continuously into atmosphere. The cokes get down 
from top to the shaft bottom and the “cold” coke at 
250 – 2800C. 
The gases moving in installation, is made by an 
exhausting tip VH 160/850 with Q=160.000 m3/h and 
a low pressure Δp=804x102 N/mm2. The work 
temperature of the exhausting is 180 – 2000C. 
The parameters of (ISUC) installation are: 
– warming coke temperature   1000 – 10500C; 
 – cooling coke temperature      250 –    2800C; 
– the temperature of moving gases before 
recuperation boiler: 750 – 8000C; 
 – the temperature of moving gases before the 
entrance in the recipient 180 – 2000C; 
 – the quantity of warming blow at one tone of 
coke  400 – 420 kg; 
 – the productivity of recuperating boiler is 85t/h 
of warning blow at the temperature of 430 – 4400C. 
The measuring installation has the next 
possibility: 
 – measuring the temperature of coke on the 
transported of installation; 
 – measuring the temperature of lining Y in the 
channels zone; 
 – measuring the temperature of inert gas at the 
entrance into the bottom of recipient; 
 – measuring the temperature of inert gas at the 
exit at the top shaft; 
 – measuring of the inert pressure at the entrance 
into the shaft (400 ÷450 ⋅ 102 N/mm2); 
 – measuring of the coke level into the 
installation by radioactive sources. 
3. The technology of I.S.U.C 
 
 The principally chemical reactions produced 
during the air moving into installation are: 
a) completely oxidation of the carbon from the 
coke: 
C + O2 → CO2 + 409500 kJ    (1) 
1868,4)1062,0000879,0469,097853( 362 ⋅⋅++−= − TTTq
        (1.1) 
b) incompletely oxidation of the carbon the 
coke: 
2 C + O2 → 2 CO + 248700 kJ   (2) 
1868,4)1025,1003594,0298,460320( 362 ⋅⋅++−= − TTTq
        (2.1) 
c) the reducing of water vapour from air with 
carbon (t≥9000C) : 
    H2O + C → CO + H2 – 118000 kJ  (3) 
1868,4)10546,0002719,0269,526853( 362 ⋅⋅++−−= − TTTq
        (3.1) 
d) the reducing of water vapour with carbon 
(t≤9000C) : 
         2 H2O + C → CO2 + 2H2 – 74940 kJ (4) 
1868,4)10462,0002723,0709,616162( 362 ⋅⋅++−= − TTTq
        (4.1) 
The reaction with water vapour has been in 
generally at the start of installation on at the breaking 
of recuperating boiler, when water vapour penetration 
the gases circuit. 
 
e) the methane is forming : 
C + 2H2 → CH4 + 77870 kJ   (5) 
1868,4)10182,200673,0351,1115713( 362 ⋅⋅+−+= − TTTq
        (5.1) 
f) the reducing of CO2 at high temperature no 
oxygen: 
 
CO2 + C → 2 CO – 161000 kJ   (6) 
1868,4)1063,0002715,0829,337533( 362 ⋅⋅++−−= − TTTq
        (6.1) 
With increasing of combustible elements has 
been a increase of diverse concentration whose 
combustible components into the moving gases are 
given in table 1. 
 
Table 1 Different functionary models of (ISUC) 
The composition of gases Explosion boundaries Functionary of (ISUC) 
CO H2 CH4 C CO2 N2 inf % sup% 
The 
admissible 
concentration 
No nitrogen 
23,6 7,50 0,60 0,20 4,42 63,5 8,40 75,0 5,25 
With added of 
nitrogen 12,6 3,84 0,60 0,20 6,04 76,8 8,30 65,0 7,35 
With burned of 
combustible  4,92 6,06 2,62 0,36 16,0 76,2 8,20 31,0 14,10 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI 
0FASCICLE IX METALLURGY AND MATERIALS SCIENCE, ISSN 1453 – 083X. N . 2 – 2006 
 
 
 
4. Mathematical model 
 
The analysis mode permit to appreciate the 
purpose of each thermal flux of (I.S.U.C.) for a 
energetically efficiently of this process. 
The optimal regime for recuperating boiler of 
(ISUC) who keeping the warming blow parameters is 
the calculus regime for a production of 25 t/h and a 
productivity at 50 t/h cooling coke at gases debit of 
82000 m3N/h at a entrance temperature of gas into the 
recuperating boiler of 8000C. 
The primary thermal fluxes of I.S.U.C. are 
burning coke and sour–warm steam. The link 
between these two fluxes is making by flux of 
moving warm gas. If the energy of sour–warm steam 
is highly, the energy at the exit from dry cooling 
room is much highly and too is aspect a greatest 
energy at the exit of recuperation boiler and grow the 
efficiently of I.S.U.C. like energotechnology system. 
The values of energetically losses are 
characteristics of coke dry cooling and can be 
considered like efficiently criterions. 
For a optimally developing of coke dry cooling 
is necessary to study the efficiently criteria and to 
determine by measuring the total energetically looses 
and than to find the way increase the efficiently of 
I.S.U.C. The most important problem is to diminish 
the total energetically looses (equation 7).  
 It must to find the order variable of this process 
and than to drive in a optimal way the I.S.U.C. 
Qp = f ( Xi ) = min    (7) 
were: 
  Xi – technological variable; (i=1, 2, 3,   , k) 
The most important energetically looses is 
generated by a badly change of warm into – the dry 
cooling room, the recuperation boiler, looses of 
moving gas throw the aspiration smoke pipes, the 
temperature of gas flux at the exit of recuperation 
boiler and the flux of dry coke. 
All looses of coke dry cooling plant are describe 
in the next equation: 
Qp =–5,53 + 4,37⋅10–4X1 + 0,96⋅10–4X2 + 0,61⋅10–4X3 
+ 4,22⋅10–4X4 + 1,55X5  + 1,38X6           (8) 
 
Equation is not valid at the boundary: 
 36000 ≤ X1 ≤ 54000    (9) 
 X2 ≤ 160000     (10) 
 1400 ≤ X3 + X4 ≤7000   (11) 
 0,0039⋅( X2 + X3 + X4 ) ≤ 630  (12) 
 1,2 ≤ X5 + X6 ≤ 5    (13) 
0,0324⋅X1 – 0,0176X2 + 111⋅X5 + 110 X6–120 ≤ 250
        (14) 
were: 
  – X1 – the consumption of burning coke, [t/h];  
 – X2 – consumption of moving cold gas, [m3/h];  
 – X3 – consumption of gas, [m3/h];  
 – X4 – consumption of gas throw aspiration 
smoke pipe, [m3/h]; 
 – X5 – the increase of contents of CO2 in 
moving gas, %; 
 – X6 – the increase CO in moving gas, %. 
For to know the minimal energetically looses is 
necessary to find the values of X1÷X6 
(technologically variables). 
The efficiently criterions is a linear function and 
boundary equations (9) – (14) are binary, than for 
solving minimized problem is used the SIMPLEX 
method of linear programming. 
The transforming of boundary equation at the 
canonized tip throw nearly transformation in 
corresponding with (9)–(14) is very complicated. For 
a really solving of this system of equation is used a 
performed computers and same algorithm for left and 
right zone by making 5 iteration (left) and 6 iteration 
(right). In table no. 2 is shown the results of this 
calculus.
 
Table 2 
 
Left zone Right zone The tehnological 
variables Optimum 
values 
Real values Optimum 
values 
Real values 
X1 54 – 42 22 
X2 86243 69323 54750 107045 
X3 6989 – 1400 5400 
X4 1,3 3,8 – – 
X5 – – 1,4 4,2 
X6 27,98 – 18,23 – 
 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI 
0FASCICLE IX METALLURGY AND MATERIALS SCIENCE, ISSN 1453 – 083X. N . 2 – 2006 
 
 
5. Conclusion 
 
 The productivity of coke plant is dependent of 
consumption of the coke. The temperature of dry 
coke order variable and can be mention between two 
borders. 
Another component of energetically looses is 
moving flux gas. The decrease of this component is 
possible by reducing the temperature of gas flux often 
recuperating boiler. The consumption of cold gas is 
conditioning by charging of coke and the asked for 
temperature of dry coke. 
 If the energy in recuperating boiler is much, the 
temperature of gas is low and the functionary of plant 
is good (efficiently). The decrease of morning gas 
temperature make possible reduce of energetically 
looses and can be assured a good transmission of 
alimentation water into the boiler. The looses in pipes 
rooms and smoke aspiration is not too much. 
 For to reduce the energetically looses by pipes 
is necessary to decrease or to close completely the 
room pipe and to eliminate the surplus of cold 
moving gas and in the same time is grow up the 
ecological security. 
 The looses resulting by the burning of coke can 
be reduced by diminish of oxygen aspiration from air 
in the channel of moving gas. 
The value of oxygen aspiration is dependent of: the 
degrees of opening of smoke aspiration pipes and the 
guide apparatus of smoke aspiration. The two factors 
are considered for regulation actions in channel.  
Thus, for the effective progress of coke dry 
quenching process, i.e. for the reduction of the energy 
losses in the installation, as it results from the 
analysis, the following must be provided: minimum 
possible temperature of quenched coke, required 
value of the discharges in the circulation system (so 
as aspirations to be minimum), the minimum 
temperature of the circulation gas at the entry in the 
quenching chamber, the optimum feeding water 
quantity in agreement with the level of the boiler. 
 
 
References 
 
 
[1]. Constantinescu I. şa - „Prelucrarea datelor cu calculatoare 
numerice” Ed. Teh., Bucureşti 1990.  
[2]. Taloi D., Florian E. - „Optimizarea proceselor metalurgice”, 
Ed. Did. şi Ped. Bucureşti 1983 
[3]. Hilbert M., Sundman B. şa – Metall. Trans. A, 1990, vol. 21, 
p2759 - 2776. 
[4]. Ienciu M. , Berca F. sa –„Produse cărbunoase”  Bucureşti, 
Litografia I.P.B. 1989 
[5]. Stefanescu D., Marinescu M., şa – „Transferul de căldură in 
tehnică”, Ed. Teh., Bucureşti 1982 
 
 
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The Decreasing of the Energetic Losses at a Coke Dry Cooling Plant

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The Decreasing of the Energetic Losses at a Coke Dry Cooling Plant

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