JPH02166237A - Operation of autogenous furnace - Google Patents

Abstract

PURPOSE:To operate an autogenous furnace at the minimum energy cost by using the material balance model and heat balance model of the furnace and its equipment at the time of operating the furnace for producing the copper sheet from a copper sulfide concentrate. CONSTITUTION:The copper sulfide concentrate 10 is dried in a drying furnace 3 by the hot air 11 from a hot air stove 2, supplied to the autogenous furnace 1, and melt- refined into the matte 24 of copper by the combustion heat of fuel and air. The matte is sent to a converter 25 and oxidation-refined into crude copper. In this case, the high-temp. exhaust gas 17 from the furnace 1 is sent to a waste-heat boiler 4 to generate steam 18. The steam is heated in a steam heater 5 by a fuel 21 (heavy oil or coal), and sent to an air preheater 6. The heated air is utilized to dry the concentrate 10. A part of the steam 18 is injected with water by a temp.-reducing water injector 7, and the temp. is controlled. The steam is heated to a specified temp. by a steam reheater 8 along with the steam 19 from a converter boiler, and utilized in a generator steam turbine 9. The conditions to minimize the energy cost for the whole furnace system are obtained by an electronic computer from the material and heat balance models in the furnace system. The furnace is operated under such conditions always at the minimum energy cost irrespective of the variations in the operational condition.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a flash smelting furnace that produces acid using sulfide concentrates such as copper as a main raw material, and a method of operating energy utilization equipment attached to the flash smelting furnace. be.

[Conventional technology]

Traditionally, flash melting furnaces that use sulfide concentrates such as copper as raw materials have been equipped with various devices such as those shown in Figure 1 in order to recover the waste heat of the flash melting furnace and to preheat and dry the concentrate. It is used as ancillary equipment.

The flash-melting furnace and the flash-melting furnace auxiliary equipment include the flash-melting furnace 1 and the flash-melting furnace I.
A drying furnace 3 equipped with a hot blast furnace 2 for drying the raw material concentrate to be charged, a waste heat boiler 4 connected to the flash melting furnace IG, and a steam heater coupled to the waste heat boiler 4. 5, an air preheater 6 coupled to the steam heater 5, a steam reheater 8 coupled to the air preheater 6 via a cooling water injector 7, and from the steam reheater 8. It consists of a steam turbine 9 that generates electricity using the obtained steam, and when used, the raw material concentrate IO to be charged into the flash smelting furnace 1 is generated by burning the raw material concentrate IO in the drying furnace 3 and the fuel (heavy oil) 20 in the hot blast furnace 2. Dry raw material concentrate obtained by drying using hot air 11, exhaust gas 12 from burning fuel (heavy oil/coal) 21 in steam heater 5, and exhaust gas 13 from burning fuel (heavy oil) 22 in steam reheater 8. 14 is charged into the flash melting furnace 1 together with fuel (heavy oil/coal) 15 and reaction air 16, and the dry raw material concentrate 14 is oxidized and dissolved.
The generated waste gas 17 is introduced into a waste heat boiler 4G to generate steam 18. The generated steam 18 is introduced into the steam heater 5, heated to the required temperature, and then sent to the air preheater 6. Combustion exhaust gas 1 generated in steam heater 5
2 is introduced into the drying furnace 3 and used for drying the raw material concentrate 10 as described above. The air preheater 6 preheats the reaction air 16 used in the flash-melting furnace 1, and if necessary, the steam 18 is injected with a cooling water injector 7 to adjust the temperature, and is combined with the converter boiler steam 19. The steam reheater 8 raises the temperature to a predetermined temperature.

The combustion exhaust gas 13 generated in the steam reheater 8 is introduced into the drying furnace 3 and used for drying the raw material concentrate 10. The steam heated in the steam reheater 8 is sent to a steam turbine 9 and used for power generation.

By the way, in order to reduce the energy cost of the above-mentioned flash-melting furnace and the flash-melting furnace auxiliary equipment as a whole, the temperature at the drying furnace entrance was set at 500°C.
JP-A No. 62-263934 discloses an operating method that maintains the air pressure at ~650 U and minimizes the amount of fuel used in the hot stove.

However, the above operating method is not satisfactory in cases where the oxygen enrichment ratio of the reaction air used in the flash-melting furnace is varied depending on the operating conditions.

That is, (1) When increasing the oxygen enrichment ratio When changing from low oxygen enrichment operation to high oxygen enrichment operation, the volume of reaction air decreases, and as a result, the exhaust gas 17 of the flash furnace 1 decreases. The volume of will also decrease. However, since the temperature of the exhaust gas 17 does not change much, the amount of steam generated from the waste heat boiler 4 decreases. Further, in proportion to the decrease in the reaction air volume, the fuels 21 and 22 in the steam heater 5 and the steam reheater 9 decrease, and the base of these combustion exhaust gases 12 and 13 also decreases. As a result, the amount of heat supplied to the drying oven 3 becomes insufficient, and the amount of fuel 20 used in the hot blast oven 2 must be increased. Furthermore, in the air preheater 6, the effect of reducing the amount of reaction air 16 to be preheated is greater than the effect of reducing the amount of generated steam 18, and as a result, the outlet steam temperature of the air preheater 6 increases. Therefore, the amount of fuel used for reheating in the steam reheater 8 is reduced to the extent that combustion in the burner becomes difficult, and water is injected by the cooling water injector 7 to lower the steam temperature at the inlet of the steam reheater 8. If there is no inflow of converter waste heat boiler steam 19, even if water is injected to the upper limit of the capacity of the cooling water injector 7, the inlet steam temperature of the steam reheater 8 will not reach the steam temperature at which heavy oil banner can be stably combusted. A situation arises where it does not go down.

(2) When reducing the oxygen enrichment rate When changing from high oxygen enrichment operation to low oxygen enrichment operation, the volume of reaction air increases, and as a result, the exhaust gas 17 of the flash furnace 1 increases. The volume also increases. However, since the temperature of the exhaust gas 17 does not change much, the amount of steam 18 generated in the waste heat boiler 4 increases.

Furthermore, in order to heat the increased reaction air 16 to a predetermined temperature, a large amount of the fuel 21 in the steam heater 5 is combusted to raise the outlet steam temperature to the upper limit of the device. The volume also increases, and the amount of heat brought in by the steam heater exhaust gas 12 introduced into the drying furnace 3 increases, resulting in excessive heat input and the amount of fuel used in the hot blast furnace 2 must be reduced to the extent that stable operation of the burner becomes difficult. However, even if the combustion is stopped, there will be excess heat, and the raw material concentrate 1 will be lost in the drying furnace 3.
A situation arises in which part of the exhaust gas 12 must be released into the atmosphere in order to prevent the combustion of the exhaust gas 12.

(3) ``If the amount of concentrate processed in the drying furnace decreases, in this case too, excessive heat input will occur, and in order to prevent the amount of fuel used in the hot blast furnace 3 from reaching a level where stable operation of the burner becomes difficult, 1
A situation arises in which part of the exhaust gas must be released into the atmosphere.

When such a situation occurs, operating conditions must be changed to minimize energy costs while considering the overall impact, but the operating method described above does not accommodate changes in oxygen enrichment, etc. However, the operating conditions had to be determined separately based on the experience and intuition of skilled workers, and it was not always possible to operate under operating conditions that would minimize energy costs.

[Problem to be solved by the invention]

An object of the present invention is to quickly determine and operate the operating conditions of a flash melting furnace and its auxiliary equipment so that the energy cost of the entire system is always minimized, regardless of changes in the oxygen enrichment ratio.

[Means to solve the problem]

The present invention provides a flash melting furnace that uses coal and/or heavy oil as auxiliary fuel; a waste heat boiler that recovers heat from the exhaust gas of the flash furnace; steam from the waste heat boiler is heated by combustion of coal and/or heavy oil. an air preheater that preheats oxygen-enriched reaction air to be supplied to the flash furnace by the steam heated by the steam heater; an air preheater that preheats oxygen-enriched reaction air by burning coal and/or heavy oil; a steam reheater that reheats the steam that has passed through the steam reheater by burning heavy oil; a steam turbine for operating a generator that is driven by the steam that has passed through the steam reheater; an exhaust gas from the steam heater and the steam reheater; In a method for operating a flash melting furnace equipped with hot air obtained by burning heavy oil in a hot blast furnace and a drying furnace that dries the raw material concentrate supplied to the flash melting furnace: Each substance produced from the material balance in the flash melting furnace. While determining the amount, solve the first LP model by linear programming combining the following formulas [1] to [3] to determine the amount of steam generated in the waste heat boiler, and use this value to calculate the following [1] to [3]. 3
] Solve the second LP model created using the formula and calculate until the reaction air temperature converges to obtain the heavy oil usage and coal usage, and then calculate the heavy oil usage and coal usage, and the waste heat boiler. Calculate the energy cost using the amount of power generated by the steam turbine determined from the amount of steam generated at , and the total amount of electricity required, and repeat the above calculation until the obtained energy cost is minimized. The amount of heavy oil used as auxiliary fuel in the flash-melting furnace, the amount of heavy oil used in the steam heater, the amount of heavy oil used in the steam reheater, which is the optimal operating condition.
A method for operating a flash-melting furnace, characterized in that the amount of heavy oil used in the hot blast furnace, the amount of coal used as auxiliary fuel in the flash-melting furnace, and the amount of coal used in the steam heater are obtained, and the operation is performed according to these values. .

Qoono-Q8+QF8-(Qao+Q6, +QS,
. 2+Qo)+Q8. ■Q +X Xq
+Y Xq +Q, a, -Qm, +Q, +Q, 8■C
onCI oil I coal ten Lo
ss ■ Q8a8=WXqW+Qwg+LO°・W×(a2+b
2 x t2) + X2 x qo engineering, 1 Y2 x qoo8□
■-WX (a'2+b'2Xt'
2) +Q8b, +LossW×(a'2+b'2×t'
2)=WX(a″2+b″2×T″2)■10S X(
(t'2-T,) + (T"2-25) )Xi/2
XK+Lossp W×(a″2+b″2×T″2)+X3×qo engineering,=W
×(a3+b3×t3)+Qrb8+LOSS■Q6b
8+Qrbg+x4×qo 1-Qdo+QdW+Qd
g+L0°8 ■In each of the above formulas, Q - amount of heat generated by concentrate reaction (Meal/H)
onc Q - Heat generated by combustion of sulfur i (Mcaj/H
) Q, F8 = amount of heat generated by oxidation of iron (Mcal/
H) Q = amount of heat required for decomposition of charged concentrate (Mca
l/H) a Q = amount of heat required for decomposition of charged smoke ash (McaA/
H)i Q8□. 2-The amount of heat required for the decomposition of the charged silicate ore (M
eal/H) Q - Amount of heat required for decomposition of charge miscellaneous material (Mcat/H)
H) Q - amount of heat generated by the generation of warmth (Mcal/
H) sf
/l() q - Unit calorific value of heavy oil (Kc a l/
kQX 10-3) Y - Amount of coal burned as auxiliary fuel in a flash-melting furnace (kg/H) qcoal - Unit heat generation of coal if (K c
a l/kg×10-3) Q, - Heat capacity of the reaction air used in the flash melting furnace (MOa l/H) Q - Heat capacity of the air generated by the reaction in the flash melting furnace (Mca
l/H) Q - The amount of heat generated in the flash-melting furnace (lvlqa7
/H) I Q - as Heat capacity of the waste gas generated by the reaction in the flash-melting furnace (MOal/H)Los
s-loss heat El (Mcal/
H) W - Amount of steam generated in the waste heat boiler (T/I()
q - unit heat of vaporization of steam generated in the waste heat boiler (Mc
aJ/T) Q - Exhaust heat boiler exhaust gas retained heat (Mc al/H
) g a - Constant for determining the specific heat per unit steam of the steam at the inlet of the steam heater (McaJ/T) b2 - Coefficient for determining the specific heat per unit steam of the steam at the inlet of the steam heater (Mc a l/T- c) t - Steam temperature at the inlet of the steam heater (tl?) a'2 - Constant for determining the specific heat per unit steam of the steam at the outlet of the steam heater
(McaA/T) b'2 - Coefficient for determining specific heat per unit steam of steam heater outlet steam
(Mc ELI/T-'C) t' - Steam temperature at the outlet of the steam heater (c) X - Amount of heavy oil used in the steam heater (kg/H) Y = Amount of coal used in the steam heater
(kg/H) Qsbg - Heat capacity of the exhaust gas generated in the steam heater (Mehl/H) a''2 - Constant for determining the specific heat per unit steam of air preheater outlet steam (Mcal/T) b''2 −
Coefficient for determining specific heat per unit steam of air preheater outlet steam (Mca7!/T-U)T J/-
Air preheater outlet steam temperature (c) S = Air preheater heat transfer area (a) p T - Reaction air temperature (tr) 25 -
Air preheater inlet air temperature 1) K = overall heat transfer coefficient (Kca4J-H-tXlo -3
)X-Amount of heavy oil used in the steam reheater (kg/H)a
- Constant for determining the specific heat per unit steam of the steam at the steam reheater outlet (McaJ/T)b - Coefficient for determining the specific heat per unit steam of the steam at the steam reheater outlet
(Mcal/T-tr) t = Steam temperature at the outlet of the steam reheater (1?,) Q = Heat retained in the exhaust gas of the steam reheater (Mc a t/H)bg X - Amount of heavy oil used in the hot blast furnace (kg/ H)Q
= Amount of heat removed from the raw material after drying (Mcal/H) a Q - Amount of heat of evaporation of the water removed by drying w (Mcal/H) Q - Amount of heat retained in the exhaust gas generated in the hot air stove g (McaJ/H ) [Operation] In the present invention, a computer calculates the conditions under which the energy cost is minimized for the entire system using a material balance model and a heat balance model for the flash furnace and its ancillary equipment. We will explain the material balance model and heat balance model.

(1) Overview of operation in each device and related material balance model and heat balance model ■ Flash melting furnace heat balance In the flash melting furnace 1, powdered raw material concentrates 10 and 7 lux, auxiliary fuel 15, etc. are used for reactions such as preheated air. The raw material concentrate 10 is blown into the furnace from a concentrate burner together with air 16, and sulfur and iron, which are combustible components in this raw material concentrate 10, react with the reaction gas 16, and the solution is stored in a part of the settler. Depending on the difference in specific gravity, the solution is divided into rust whose main components are 2FaO・SiO and Cu.
The needle 24 is a mixture of 2S and FsS.

Then, the heat is discharged to the outside of the flash melting furnace, and the anchor 24 is intermittently extracted from the flash melting furnace 1 in response to a request from the converter 25 in the next process. Further, the combustion exhaust gas 17 is supplied to the waste heat boiler 4.

The material balance model in this flash-melting furnace 1 is shown as follows. In this case, Moo - Charging concentrate M ('r7 old M
d□-Amount of smoke ash (T/H)M-
Charged amount of silicic acid (T/H)M - Charged amount of miscellaneous materials (T/H)Mair - Oxygen required for reaction of charged concentrate (T/H)M = Production amount
(T/H) Ms□=Amount of production volume
(T/H) M. = Amount of smoke and ash generated
(T/H)M = amount of exhaust gas generated
(T/H')as.

Also, the amount of reaction air 16 required for this reaction - Ma
ir(Nm7H) is expressed by the following formula.

Ma, r=Mai,, + (X, XAol, 10Y, XA
ooa,)
Amount of heavy oil burned as auxiliary fuel (kg/H) Ao
□, - Amount of air required to burn 1 to 9 heavy oil (Nmz
~] Y - Coal fj1 to be burned as auxiliary fuel. ckg/
H). . The amount of air (Nrn/kg) required to burn 1 kq of 8-ni coal. P - Oxygen loading rate.

Further, the amount M of wrinkles generated can be obtained from the following formula.

M = ((MXO+HXC, -1-MXO)
-(M Xma cone con, c d
i dlslO+HXO)l÷C sl do do ma Here, C-Cu grade of charged concentrate (wt%) conc Cd knee charge adult smoke ash Cu grade ()C-Cu grade of charged miscellaneous material (〃)C -Cu grade of rust ()Cd0=Cu grade of generated smoke ash (〃)C-Cu grade of scissors
() Also, the generated weight Msl is determined by the following formula.

M - ((M XC! +M', XO
, +MXO, +sl conc conc
sl dl disyu 0 081M,
XO,)-Mxc,)÷a8102 51
o2si do dosl 5lsi kokude, c, = SiO grade of charged concentrate (weight%) co
ncsl C- SiO grade of charged smoke ash (〃 disi 2
C = SiO grade of charged miscellaneous material (〃〕○si
2C0 = SiO grade of charged silicate ore (〃)S:LO2812 C-SiO grade of generated smoke (〃) dosi
2Cj, - SiO grade in iron (〃) Also, the amount of waste gas generated is given by the following formula.

G1=SO+O+H+(!O+H0 In this case, G1-Amount of waste gas generated in the flash-melting furnace (NmyH)SO-(
Amount of S in waste gas Amount of S in 10 heavy oil Amount of S in 10 coal) x 22.4 ÷
32.1 (Mm'/H)O = required ore air amount x oxygen enrichment rate x (1-oxygen efficiency) (N1n
/H) N = reaction air amount x (1-oxygen enrichment rate) + coal combustion amount x N grade in coal x 22.4 ÷ 28.0 (Ntn7H)
aO = (Amount of heavy oil burned x O grade in heavy oil 10 Amount of coal burned x C grade in coal) x 22.4 ÷ 12.0 (lJ++
! 'a) HO - Air amount x Moisture percentage Burnt amount of heavy oil x H in heavy oil
Grade X 22.4÷2 + coal combustion amount x H grade in coal x2
2.4÷2CNm7H> 22.4=Gas constant 32.1-Atomic weight of sulfur 2
8.0=Nitrogen molecular weight 12.0-Number of carbon atoms 2-Hydrogen molecular weight Among the above substance amounts and qualities, the following are given as given conditions.

Charging concentrate amount (M), charging ash amount (Mdi), charging o
nC Silicate ore amount (M), amount of charged miscellaneous materials (M), amount of smoke ash generated (
102 (, Amount of air required to burn 1 kg of heavy oil (A
), the amount of air required to burn 1 kg of coal (A
), oxygen enrichment rate (P), Cu grade of charging concentrate oal (C), Cu grade of charging smoke ash (C), charging miscellaneous conc

Cu grade of ai (C,,), Cu grade of rust (C
), Cu grade of generated smoke ash (0), Cu grade of s (C),
Charging concentrate do
S10 grade (C) of ma, SiO grade of charged smoke ash (2 concsi
2C], SiO grade of charging material (0,), charging silicon dis1
SiO grade of diacid ore (0,), SiO grade of generated smoke 2
51o2si
2nd place ((!d.,), Si○2 grade in iron (C8,8,), oxygen efficiency, N grade in coal, C grade in heavy oil, C grade in coal, moisture content, H grade in heavy oil, The coal is of H grade.

The above material balance is normally calculated by a person skilled in the art using given conditions, and does not particularly characterize the present invention.

In this step, a large amount of heat is generated due to the above reaction and combustion of the fuel, and the amount of heat generated due to the reaction of the concentrate is expressed by equation 0.

Qo. . . =Q8+QFe-(Q,.10Q, □10Q61
o2+Qo)+Q8. ■In this, the amount of heat generated by the Q - concentrate reaction (Mcal/H
) onc Q - amount of heat generated by combustion of sulfur (Mcal/
H) QFo = amount of heat generated by oxidation of iron (Mc
al/H) Qdc - heat required for decomposition of charge concentrate (Me a 7/H) Qdi - heat required for decomposition of charge smoke fi CMCal/H) Qsi. 2 - Amount of heat required for decomposition of charged silicate ore (Mcaj/H) Q - Amount of heat required for decomposition of charged silicate ore (McaJ/H)
H)Q8. , the amount of heat generated by the production of -g (M
CaJ/H) This heat balance model in the flash-melting furnace can be expressed as a zero-order equation, but the limiting condition at this time is23). The allowable heat load must not be exceeded.

Q+X1×qo□, +Y, 1×q0゜a1+Qa, -Q
□, 10Q8. 10-80 L o s s ■ X - Amount of heavy oil to be burned as auxiliary fuel in the flash furnace (kg
/H) qoil - Unit calorific value of heavy oil (Kca4/k
G
a 4/ks +
a, //H) QB□ - Heat capacity of the tsuba generated in the flash-melting furnace
l/H) Qgas - The amount of heat retained by the waste gas generated by the reaction in the flash furnace (Mc aJ/H) Loss - The amount of heat lost (McaJ
/H) (24) ■Waste heat boiler In the waste heat boiler 4, the exhaust gas 17 discharged from the flash furnace 1
Steam 18 is generated with the retained heat amount, the exhaust gas temperature is lowered to a temperature that can be treated by the electrostatic precipitator in the next step, and the exhaust gas is discharged as waste heat boiler exhaust gas 23, and the generated steam 18 is introduced into the steam heater 5. The steam is sent to the steam heater 5 as a steam heater.

The heat balance in this waste heat boiler 4 can be expressed by the equation 0, and the amount of steam generated can also be determined using the equation 0.

Q=WXq +Q+Loss ■gas
w wg Here W - Amount of steam generated in the waste heat boiler (T/H) qW
- Unit heat of vaporization (McaA) of the steam generated in the waste heat boiler
/T) Q = Heat capacity of waste heat boiler exhaust gas (Mcal/H
)wg Note that the limiting condition for the waste heat boiler is that the temperature of the waste heat boiler exhaust gas must be at a temperature that can be processed by the electrostatic precipitator.

■Steam heater The steam heater 5 burns heavy oil, pulverized coal, etc., raises the temperature of the steam I8 introduced into the steam heater 5, sends it to the air preheater 6, and uses the combustion exhaust gas 12 as a drying gas to the drying furnace 3. to be discharged. The heat balance in this steam heater 5 can be expressed by equation 0. Note that the steam loss in the steam heater 5 can be ignored.

Wx(a2+b2×t2)+x2×q00,+Y2×q
ooa, = wx (a'2+b, ix7'2) 10Q+L
o s s ■ bg a - Constant for determining the specific heat per unit of steam of steam at the inlet of the steam heater (Mcaj/T) b - Coefficient for determining the specific heat per unit of steam of the steam at the inlet of the steam heater (M c a l/T-・tT)t
=Steam heater inlet steam temperature (r)a' - constant for determining specific heat per unit steam of steam heater outlet steam (Me a l/T)b' - specific heat per unit steam of steam heater outlet steam Coefficients for finding
(M Q a 7/T -C) t' - Steam temperature at the outlet of the steam heater (1?) X = Use of heavy oil in the steam heater! (kg/H) Y = Coal usage i in the steam heater (kg/H) Q = Heat capacity sbg of exhaust gas generated in the steam heater (Mcal/H) Also, exhaust gas generated by combustion of heavy oil and pulverized coal The amounts are shown by formulas 1-1 and 2-2, respectively.

o = x × (R + (p-1)XA)
■-12oil1 2 oil
oilG = Y X (A' + (
p-1)XA) ■-22coal 2
coal coal
Here, G = amount of exhaust gas generated by heavy oil combustion (IJn+/
H) o11 A' - Theoretical combustion waste gas amount of 1 kg of heavy oil (Nm'/
9) Oil G - Amount of exhaust gas generated by coal combustion (Nm7H)
coal A' - Theoretical amount of combustion waste gas for 1 kg of coal (N71
'A9] oal P = Air ratio Exhaust gas generated by this heavy oil combustion X1t (G )o
i1, the amount of exhaust gas generated by coal combustion (G), and 2
The amount of heat retained in the steam heater exhaust gas (Q) is calculated using c o al .

The limiting conditions for the steam heater are that the upper limit temperature for use of the steam heater and the combustion amount of heavy oil, pulverized coal, etc. are within the range possible for the equipment.

In the present invention, whether the fuel used in the steam heater is heavy oil or pulverized coal, or what the mixing ratio is, is determined by
Although it is preferable to perform calculations using both X and Y as variables, doing so would result in an excessively large amount of calculation, so it is desirable to set one of X and Y to a fixed value.

(2) Air preheater The steam heated by the steam heater 5 is introduced into the air preheater 6, and after preheating the reaction air 16, is sent to the cooling water injector 7. Further, the preheated reaction air 16 is sent to the flash-melting furnace 1. For convenience, it can be considered that the steam increase in the cooling water injector 7 and the steam loss in the air preheater 6 cancel each other out, and that only heat exchange with the reaction air 16 is occurring. The heat balance of the air preheater 6 can be expressed by equation 0.

W×(a′2+b′2×t′2)=W×(a″2+b″
2×T''2)+S Xt (t'2-T,) +(T
``2-25) l cutting / 2 Coefficient for determining specific heat per unit steam of outlet steam (McaJ/T-'lZ')
T″=Air preheater outlet steam temperature (tr)S −
Air preheater heat transfer area (ze)p 25 = Air preheater inlet air temperature (tr)K-
Overall heat transfer coefficient (Kcaj/yf・HI
ZX10=) The air preheater inlet air temperature is a value determined from the environment of the equipment used by the present inventors, and actually varies depending on the environment in which the equipment is installed.

The limiting conditions for air preheaters are the usable temperature of the device and the capacity of the combustion burner.

■Steam reheater If the steam discharged from the air preheater 6 is so high that it does not need to be heated in the steam reheater 8, the combustion burner of the steam reheater 8 is stably combusted in the cooling water injector 7. Water is injected so that the temperature is lower than the temperature that can be used, and if there is inflow of converter boiler steam 19, it is combined with the converter boiler steam 19, and then the water is poured into the steam reheater 8.
It is heated until it reaches the temperature required by the steam turbine 9 in the next step. (b) If the heat balance up to the air preheater 6 is maintained and each amount of heat is appropriate, the water injection is unnecessary, and the converter boiler steam 19 does not need to be considered from the purpose of the present invention. . Therefore, it is sufficient to calculate the heat balance assuming that the air preheater outlet steam is directly introduced into the steam reheater as the steam reheater inlet steam. Therefore, the heat balance model in the steam reheater 8 can be expressed by equation 0.

W×(a″2+b″2×T″2)+x3×qOi,=W
X (a 10b Xt)+Q 10Loss
■3 3 3 rbg Here, X=Amount of heavy oil used in the steam reheater (kg/H)a=
Constant for determining the specific heat per unit steam of the steam at the steam reheater outlet (McaJ/T) b - Coefficient for determining the specific heat per unit steam of the steam at the steam reheater outlet
(Mcal/T-Dt = Steam reheater outlet steam temperature (tT) Q - Steam reheater exhaust gas retained heat (Mcal/H) rbg The amount of combustion exhaust gas is shown in ■-1 above, and from this Q
is required.

The limiting conditions in the rbg steam reheater are the usable temperature of the device and the capacity of the combustion burner.

(drying equipment) The combustion exhaust gases 12 and 13 generated in the steam heater 5 and the steam reheater 8 are combined and sent to the drying furnace 3. In the drying equipment, the copper concentrate is dried to a predetermined moisture content, and the amount of heat for this is obtained from the exhaust gas 12, 13 and the hot air generated by the hot air stove 2. Therefore, the heat balance model here is expressed by equation 0.

Q=Q +XXq =Q +Q +Q
+Loss ■sbg rbg 4 oil
dc dw dg Here, Q - Heat capacity of steam heater exhaust gas (Mca4/″H
)rbg Q - Steam reheater exhaust gas retained heat (Meat/H
)rbg X-Amount of heavy oil used in hot stove Ckg/H)Q
= Amount of heat removed from the raw material after drying (Mcal/H) d
c Q - The amount of heat of evaporation of the water removed by drying w (McaJ/H) Q - The amount of heat held by the exhaust gas generated in the hot air stove g (MOa l/H) The limiting conditions for this drying equipment are the These are the moisture content and the drying atmosphere temperature. The moisture content of the raw material concentrate is given as a given condition, but this determines the amount of evaporated water,
The heat of water evaporation is determined. Furthermore, if the drying atmosphere temperature is too high, the raw concentrate will burn in the drying furnace, and if it is too low, the drying will be insufficient no matter how much the air volume is increased. Since the upper and lower limits of the drying atmosphere temperature are determined by the equipment used, it is necessary to determine the upper and lower limits in advance when applying the present invention.

(2) Steam Turbine Steam brought to a predetermined temperature by the steam reheater 8 is introduced into the steam turbine 9 and used for power generation.

The relationship between the amount of power generation and the amount of steam is expressed by equation 0, but since this relationship and the required temperature of steam vary depending on the equipment used, it is desirable to investigate and determine it in advance.

W = WXal+bl ■Here, W- Amount of steam generated in the waste heat boiler laboratory (T/H) W-
Power generation amount (KWI(/H)a
l - Power generation coefficient by steam (KwH/T)b
l = Power generation constant by steam (KwH/H) (2
) Balance Calculation In the present invention, each of the heat balance models described above is converted into a linear equation, and a solution is obtained using an HP (linear programming) model using an electronic computer. However, some of the equations are non-linear and cannot be solved as one LP model, so we combine the above equations 1 to 2 while calculating the amount of each substance generated using the given conditions and the material balance model. Using the first TJP model, determine the amount of steam generated in the waste heat boiler, use this value to solve the second LP model created using formulas ■ to ■, and calculate until the reaction air temperature T converges. to determine the amount of heavy oil and coal used in each device.

It should be noted that, as shown in the section on each income and expenditure calculation above, each equation has its own limitations due to the equipment, etc., so it goes without saying that these should be taken into consideration when solving the equations.

The amount of heavy oil used and the amount of coal used determined by the above calculation,
The energy cost is calculated according to the following formula using the total amount of power used by each facility and the amount of power generated using the above formula 0.

E-(X +X +x +x)XQ 10(Y 10Y)Xo 0 S tj 2 3 4
0 f 11 2■ooa, ten (W2
"+) 4゜kok, F - Energy cost (yen/H)o
st ■ - Heavy oil unit price (yen/9)
■coal = Coal unit price (yen/to 9) W - Total amount of electricity used for the flash-melting furnace and its auxiliary equipment (KW) t/I ()W
-Amount of electricity generated (KwH/H) Q = Unit price of purchased electricity (Yen/KwH) Then, amount of heavy oil used (X
N X XX % X ) and coal consumption (Y :
The above calculation is repeated using an electronic computer until y > is obtained.

Based on the values of x , x , x , x , y , y that minimize the energy cost obtained in this way +
23412 Perform operations.

As explained above, the present invention creates a plow LP model based on the heat balance model in each process, performs calculations using the solutions obtained in the LP model until the cost calculation value is minimized, and optimizes the Although the amount of fuel is determined, it is desirable to determine each device constant in advance because the device constants of each facility are included when solving the LIP model.

〔Example〕

Using the flash melting furnace and auxiliary equipment shown in Figure 1, the auxiliary fuel for the flash melting furnace and the fuel for the steam heater are pulverized coal, and the fuel for the steam reheater and hot blast furnace is heavy oil, under the conditions shown in Table 1. A test operation was conducted.

First, the amount of enriched oxygen in the reaction air was set to 4800, Mm'/
As shown in Table 2, when operating as
The amount of pulverized coal used in the steam heater (Y) is 1840#/a
The amount of heavy oil used in the hot air stove (X, ) is 40Tcg/H.
By stopping the steam reheater, the steam temperature at the steam heater outlet was set at 540 C, and operation was possible without generating excessive heat.

Next, the amount of enriched oxygen was changed to 3800 Nm"/H, and the pulverized coal (3
5] The amount of pulverized coal used (Y ) was 2420 to 97H, the amount of pulverized coal used in the steam heater (Y ) was 2090 kg/H, and the steam temperature at the steam heater outlet was 540C. At this time, the hot blast furnace was stopped and the amount of combustion in the steam reheater was reduced to the lower limit of burner capacity, but the temperature inside the drying furnace still exceeded the upper limit, so the amount of heavy oil used in the hot blast furnace was reduced to 20%. Hot air equivalent to 9/H had to be released into the atmosphere.

In contrast, in the present invention, the enriched oxygen amount is reduced to 380ONm/
As a result of sequentially calculating the optimal operating conditions when changing to ) is set to 2430 VH, the amount of pulverized coal used in the steam heater (Y ) is set to 2010 kg/H, the amount of heavy oil used in the steam reheater (X ) is set to 175 kvu, and the hot blast furnace is stopped. By setting the outlet steam temperature to 527C, it was possible to operate without generating excessive heat from the hot stove or other sources.

Table 2 Table 2 [Effects of the Invention] According to the present invention, a flash melting furnace can be operated under optimal operating conditions where energy costs are always minimized despite fluctuations in operating conditions.

[Brief explanation of the drawing]

The figure shows a conceptual diagram of the flash-melting furnace and its auxiliary equipment. 1... Flash melting furnace 3... Drying oven 5... Steam heater 7... Temperature reduction water injector 9... Steam turbine 11... Hot air 14... Dry raw material concentrate 16... Reaction air 18... Steam 20 .21.22...Fuel 24...Flag 26...Air 2...Hot stove 4...Waste heat boiler 6...Air preheater 8...Steam reheater 10...Raw material concentrate 12.13... Exhaust gas 15... Fuel 17... Exhaust gas 9... Converter boiler steam 23... Exhaust gas 25... Converter 27... Oxygen Applicant Sumitomo Metal Mining Co., Ltd.

Claims (1)

[Claims] (1) A flash melting furnace that uses coal and/or heavy oil as auxiliary fuel; A waste heat boiler that recovers heat from the exhaust gas of the flash furnace; Steam from the waste heat boiler is heated by burning coal and/or heavy oil. an air preheater that preheats oxygen-enriched reaction air to be supplied to the flash furnace by the steam heated by the steam heater; an air preheater that preheats oxygen-enriched reaction air by burning coal and/or heavy oil; a steam reheater that reheats the steam that has passed through the steam reheater by burning heavy oil; a steam turbine for operating a generator that is driven by the steam that has passed through the steam reheater; an exhaust gas from the steam heater and the steam reheater; In a method for operating a flash melting furnace equipped with hot air obtained by burning heavy oil in a hot blast furnace and a drying furnace that dries the raw material concentrate supplied to the flash melting furnace: Each substance produced from the material balance in the flash melting furnace. While determining the amount, solve the first LP model by linear programming combining the following formulas [1] to [3] to determine the amount of steam generated in the waste heat boiler, and use this value to calculate the following [4] to [3]. 7]
Solve the second LP model created using the formula and calculate the amount of heavy oil and coal used until the reaction air temperature converges, and then calculate the amount of heavy oil and coal used in the waste heat boiler. The energy cost is calculated using the amount of power generated by the steam turbine determined from the amount of steam generated and the total amount of electricity required, and the above calculation is repeated until the obtained energy cost is minimized. The conditions are the amount of heavy oil used as auxiliary fuel in the flash melting furnace, the amount of heavy oil used in the steam heater, the amount of heavy oil used in the steam reheater, the amount of heavy oil used in the hot blast furnace, and the amount of heavy oil used as auxiliary fuel in the flash furnace. A method for operating a flash-smelting furnace, characterized in that the amount of coal used and the amount of coal used in a steam heater are obtained, and the operation is performed according to these values. Q_c_o_n_c=Q_S+Q_F_e−(Q_d_
c+Q_d_i+Q_s_i_o_2+Q_o)+Q_
s_f[1] Q_c_o_n_c+X_1×q_o_i_l+Y_1
×q_c_o_a_l+Q_a_i=Q_m_a+Q_
s_l+Q_g_a_s+Loss[2] Q_g_a_s=W×q_w+Q_w_g+Loss[
3] W×(a_2+b_2×t_2)+X_2×q_o_i
_1+Y_2×q_c_o_a_l=W×(a'_2+
b'_2×t'_2)+Q_s_b_g+Loss[4
] W×(a′_2+b′_2×t′_2)=W×(a″_
2+b”_2×T”_2)+S_a_p×{(t'_2
-T_1)+(T″_2-25)}×1/2×K+Lo
ss[5] W×(a″_2+b″_2×T″_2)+X_3×q_
o_i_l=W×(a_3+b_3×t_3)+Q_r
_b_g+Loss[6] Q_s_b_g+Q_r_b_g+X_4×q_o_i
_l=Q_d_c+Q_d_w+Q_d_g+Loss
[7] In each of the above formulas, Q_c_o_n_c = amount of heat generated by concentrate reaction (M
cal/H) Q_S = amount of heat generated by combustion of sulfur (Mcal/H
) Q_F_e = amount of heat generated by oxidation of iron (Mcal/
H) Q_d_c = amount of heat required for decomposition of charge concentrate (Mc
al/H) Q_d_i = amount of heat required for decomposition of charged smoke ash (Mc
al/H) Q_s_i_o_2 = Amount of heat required to decompose the charged silicate ore (Mcal/H) Q_o = Amount of heat required to decompose the charged miscellaneous material (Mcal
/H) The amount of heat generated by the generation of Q_s_f=■ (Mcal/
H) X_1=Amount of heavy oil to be burned as auxiliary fuel in the flash furnace (k
g/H) q_o_i_l=Unit calorific value of heavy oil (Kcal/kg×
10^-^3) Y_1 = Amount of coal burned as auxiliary fuel in the flash furnace (k
g/H) q_c_o_a_l=Unit calorific value of coal (Kcal/k
g x 10^-^3) Q_a_i = Heat capacity of the reaction air used in the flash-melting furnace (
Mcal/H) Q_m_a = Heat capacity of ■ generated by the reaction in the flash-melting furnace (
Mcal/H) Q_s_l = Heat capacity of ■ generated in the flash-melting furnace (Mcal/H)
l/H) Q_g_a_s = The amount of heat retained in the waste gas generated by the reaction in the flash furnace (Mcal/H) Loss = The amount of heat lost (Mcal/H) W = The amount of steam generated in the waste heat boiler (T/H) q_w= Unit heat of vaporization (M
cal/T) Q_w_g=heat capacity of exhaust heat boiler exhaust gas (Mcal/
H) a_2 = Constant for determining the specific heat per unit steam of the steam at the steam heater inlet (Mcal/T) b_2 = Coefficient for determining the specific heat per unit steam of the steam at the steam heater inlet (Mcal/T・℃) t_2 = Steam temperature at the inlet of the steam heater (℃) a'_2 = Constant for determining the specific heat per unit of steam of the steam at the outlet of the steam heater (Mcal/T) b'_2 = Temperature of the steam at the outlet of the steam heater per unit of steam Coefficient for determining specific heat (Mcal/T・℃) t'_2=Steam heater outlet steam temperature (℃) X_2=Amount of heavy oil used in the steam heater (kg/H) Y_2=Coal use in the steam heater Amount (kg/H) Q_s_b_g = Heat capacity of the exhaust gas generated in the steam heater (Mcal/H) a″_2 = Constant for determining the specific heat per unit steam of the air preheater outlet steam (Mcal/T) b″ _2 = Coefficient for determining specific heat per unit steam of air preheater outlet steam (Mcal/T・℃) T''_2 = Air preheater outlet steam temperature (℃) S_a_p = Air preheater heat transfer area (m^2 ) T_1 = Reaction air temperature (℃) 25 = Air preheater inlet air temperature (℃) K = Overall heat transfer coefficient (Kcal/m^2・H・℃×10^
-＾3) X_3=Amount of heavy oil used in the steam reheater (kg/H) a_3=Constant for determining the specific heat per unit steam of steam at the steam reheater outlet (Mcal/T) b_3=Steam reheater Coefficient for determining specific heat per unit steam of outlet steam (Mcal/T・℃) t_3=Steam reheater outlet steam temperature (℃) Q_r_b_g=Steam reheater exhaust gas retained heat (Mcal/
H)
cal/H) Q_d_g=The amount of heat retained in the exhaust gas generated in the hot air stove (Mc
al/H)