CA1050786A - Method for determining the temperature of a molten metal bath - Google Patents
Method for determining the temperature of a molten metal bathInfo
- Publication number
- CA1050786A CA1050786A CA239,186A CA239186A CA1050786A CA 1050786 A CA1050786 A CA 1050786A CA 239186 A CA239186 A CA 239186A CA 1050786 A CA1050786 A CA 1050786A
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- Prior art keywords
- heat
- determining
- conversion process
- molten metal
- metal bath
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Abstract
ABSTRACT OF THE DISCLOSURE
A method is disclosed for determining the temperature of a molten metal both in a top blown oxygen converter and particularly that temperature after the conversion process has progressed a predetermined period of time and thereafter furthe rincreases in temperature as the conversion process proceeds to completion. This method is based on determining the heat content of the charge, the amount of oxygen fed to the converter and a continuous analysis of the gases evolved during the conversion process rather than having to make a direct temperature measurement, an analysis of carbon content of the charge or sampling and analyzing the hot metal fed to the converter.
A method is disclosed for determining the temperature of a molten metal both in a top blown oxygen converter and particularly that temperature after the conversion process has progressed a predetermined period of time and thereafter furthe rincreases in temperature as the conversion process proceeds to completion. This method is based on determining the heat content of the charge, the amount of oxygen fed to the converter and a continuous analysis of the gases evolved during the conversion process rather than having to make a direct temperature measurement, an analysis of carbon content of the charge or sampling and analyzing the hot metal fed to the converter.
Description
_ACKGROUND OF THE I_VENTION
1. Field of the.Invention .
This invention relates to a methocl for determining the temperature of a molten metal bath in a top blown oxygen converter and more particularly to a method for determining the temperature of a molten metal bath after the conversion process has progressed a predetermined period of time and thereafter determining the further increases in the temperature of the molten metal bath as the conversion process progresses to completion.
1. Field of the.Invention .
This invention relates to a methocl for determining the temperature of a molten metal bath in a top blown oxygen converter and more particularly to a method for determining the temperature of a molten metal bath after the conversion process has progressed a predetermined period of time and thereafter determining the further increases in the temperature of the molten metal bath as the conversion process progresses to completion.
2. Description of the Prior Art - - ~
It is highly desirable in metal conversion processes, especially in top blown oxygen converters, to determine the temperature of the molten metal ba-th as the conversion process progresses and to predict, prior to turndown, the temperature of the molten metal bath at the completi-on of th.e conversion process, It is also highly desirable to predict and control the formation of FeO in the slag which rapidly increases during the latter stages of the conversion process.
Several proposals have been made in the past for determining the temperature of a molten metal bath in a top blown oxygen converter.
For example, in U.S. patent 3,377,15~, a bomb thermocouple is dropped into the molten metal bath after the conversion process has progressed for a preselected period of time. The thermocouple measures the temperature of the molten metal bath at the time of the conversion process when it is dropped into the molten metal bath and is used as the initial measured temperature for subsequent
It is highly desirable in metal conversion processes, especially in top blown oxygen converters, to determine the temperature of the molten metal ba-th as the conversion process progresses and to predict, prior to turndown, the temperature of the molten metal bath at the completi-on of th.e conversion process, It is also highly desirable to predict and control the formation of FeO in the slag which rapidly increases during the latter stages of the conversion process.
Several proposals have been made in the past for determining the temperature of a molten metal bath in a top blown oxygen converter.
For example, in U.S. patent 3,377,15~, a bomb thermocouple is dropped into the molten metal bath after the conversion process has progressed for a preselected period of time. The thermocouple measures the temperature of the molten metal bath at the time of the conversion process when it is dropped into the molten metal bath and is used as the initial measured temperature for subsequent
3 -~ ~
~L~S0786 temperature determinations. The final temperature of the molten metal bath at the end of the conversion process is determined by adding to the initial measured temperature of the bath, the temp-erature increase attributable to the oxy~en consumed in the con-version process. The accuracy of the calculated temperature at turndown is dependent on the accuracy of the initial measured - 3a -~.
.~ . . . . . . .
, ~ I . . . .
. , - . . : .
, `` lL~SC3'7~36 temperature by the thermocouple.
It is well known that there is a temperature gradient within molten metal bath with the highest temperature .in the jet oxygen-hot metal reaction zone. It is also feasible that the slag formed during the conversion process is at a differential temperature to that of the molten metal. These ~actors affect the accuracy of determining an accurate initial measured temperature and therefore, also affect the accuracy of the calculated temperature at turndownO
Another proposed procedure for determining the temper-: 10 ature of the bath is disclosed in United States patent 3,489/518, granted on January 13, 1970, and entitled "Carbon Determination Method And Apparatus". In this process, the amount of carbon in : the charge material is first determined and the other constituents of the charge are also conventionally sampled and analyzed for heat release determination. The increase in the temperature of the molten metal bath attributable to the oxidation of the metalloids is determined by calculating the heat of formation of each of the metalloids and the heat of formation of the gaseous carbon compounds.
One of the inherent deficiencies in this method is the necessity of accurately sampling prior to analyzing the charge for the metalloidconstituents. An error in the sampling or analysis of one of the metalloids results in a -temperature error equivalent to the error in the weight of metalloid multiplied by the heat of formation of the particular metalloid.
SUMMARY O~ THE INVENTION
According to the present invention, the tempera~ure of the molten metal bath is determined by measuring the total amount of lance oxygen fed to the converter, the portion of the lance oxygen that is converted to oxides of carbon, the portion of the ::Lal 5~7~
lance oxygen that is converted to oxides of metalloicls and the portion of the lance oxygen used to oxidize the iron in the dust.
The heat added to the molten metal bath by the oxidation of the `
carbon is determined from the heat of formation of the carbon containing gases and the heat added by the oxidation of the metalloids is determined from the average heat of formation per unit volume of oxygen to convert the metalloids to their oxides.
At a preselected time during the conversion process, after sub-stantially all of the metalloids have been oxidized, the temper-ature of the molten metal bath is determined from the total heatadded to the molten metal bath by the oxidation of the metalloids and the heat added to the bath by the oxidation of the portion of the carbon during the conversion process up to the preselected time.
After the conversion process has progressed beyond the oxidation of the metalloids, the further increase in the temper-ature of the molten metal bath is determined from the portion of the lance oxygen that is subsequently converted to oxides of carbon in a similar manner. During the latter stages of the conversion process, the increasing volume of oxyyen that reacts with the iron to form FeO is measured and the heat added to the molten metal bath by the FeO formation is determined. With the above information, the increasiny weight of the slag in the molten metal bath and the decreasing weight of the molten bath may also be determined.
To determine the temperature of the molten metal bath in aocordance with the present invention, all that is required is to determine the heat content of the charge, the amount of oxygen fed to the converter and a continuous analysis of the gases evolved .
. . ' , ::
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~ during the conversion process. The present invention eliminates the necessity of making a direct temperature measurement of the molten metal bath, as by a thermocouple or t:he like, determining the carbon content of the charge by analysis or sampling and analyzing the hot metal fed -to the converter.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a graphical illustra-tion of the amount of oxygen supplied to the converter by the oxy~en lance and that portion of the lance oxygen that reacts with the carbon to form carbon containing gases and the portion that reacts with the metalloids to form metalloid oxides and the portion of the oxygen that reacts with the iron to form FeO.
Figure 2 is another graphical illustration of the con-version of the lance oxygen to the carbon containiny gases, metal- i loid oxides and ~eO and that required portion of the oxygen that infiltrates with the air in-to the flue to convert the carbon mono-xide to carbon dioxide in the flue.
DESCRIPTION OF THE PR~FERRED EMBODIMENT
In order to practice the hereinafter described process, it is necessary to have gas analyzers capable of measuring the constituents of the waste gas and to transmit this information to a computer. The computer is suitably programmed to determine from the waste or "off" gas in the flue, the composition of the gas leaving the converter before it is admixed and combusted with in-filtrating air. Other instrumentation is necessary to determine the rate of flow of oxygen through the lance, and the wei~ht, temperature and analysis of the charge. Suita~le apparatus for analyzing the waste or "off'; gas for determining the gases leaving the vessel is disclosed and described in United States patent ' ,," ~, ' " ' .
-~ 5~78~;
3,489,518, entitled "Carbon Determination Method and Apparatus".
It should be understood, however, that other apparatus may be employed to analyze the gases and transmit this information to a computer.
All temperature calculations are preferably taken at a base temperature of 2,900F. and it will be hereinafter assumed that the heat content of the various constituents at 2,900F. is zero, although any base temperature, such as ambient, may be ; employed.
To determine the temperature of the molten metal bath, the total heat content of the charge, QCHARG, is first determined from a summation of the heat content of each of the constituents of the charge according to the following:
Q CHARG = QHM + QS + QCIC + QLCM
~ Q DLC + QSPCM + QSTC
Where QHM is the heat content of the hot metal; QHM is determined by the temperature and weight of the hot metal introduced into the converter; QS is the heat content of the scrap; QCIC is the heat content of the cold iron and QLCM the heat content of the lime in the charge; Q DLC is the heat content of the dolomite in the charge and QSPCM is the heat content of the spar in the charge and QSTC is the heat content of the stone in the charge. QS; QCIC;
QLCM; QDLC; QSPCM and QSTC are determined by the weight and temper-ature of the constituents introduced into the converter.
After the total heat content of the charge, calculated from a base of 2,900F.,~ is determined, the material is charged into a top blown oxygen converter and an oxygen lance is lowered ;
into the converter. The conversion process is initiated by . . ~ . . .. .
: . -' -' ~
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supplying oxygen through the lance into the charge within theconverter. The rate of flow of oxygen through the lance is main-tained relatively constant at, for example, as illustrated in Figures 1 and 2, a rate of 15,000 SCFM. The rate oE flow of oxygen is continually measured and this information is transmitted to the computer.
The waste or "off" gas from the converter is continually measured from the beginning of the conversion process and this information is periodically supplied to a computer. The computer, from the composition of the waste gas in the flue, determines through a suitable program, the volume and composition of the gases leaving the converter before the gases are admixed with the air of infiltration. The gases leaving the converter during the conversion process, where su~stantially all of the oxygen fed by the lance reacts with the materials in the molten metal bath, consists of carbon monoxide and carbon dioxide. A substantial portion or at times, all of the carbon monoxide after leaving the vessel combines with the oxygen of the infiltrating air and is converted to carbon dioxide. The periodically measured amounts of carbon monoxide and carbon dioxide leaving the vessel and the periodically measured amounts of oxygen supplied through the lance are continually summated and recorded by the computer, After the conversion process has progressed for a sufficient period of time for the metalloids, i.e. silicon, man-ganese/ phosphorus, cobalt, titanium and the like, to be oxidized, the summated amount of oxygen supplied through the lance and the summated amounts of carbon monoxide and carbon dioxide in the gases leaving the converter are determined~ As is illustrated in Figures 1 and 2, after a conventional conversion process has progressed for ,. -, ~ , ,, ' .
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a period of about 10 minutes, with due allowance for oxidized iron, substantially all of the lance oxygen is converted to carbon mono-xide and carbon dioxide and substantially all of the metalloids have been oxidized so that little, if any oxygen is being consumed after the conversion process has progressed for a period of 10 minutes for the oxidation of the metalloids.
For convenience, the time at which the temperature of the bath is determined after the metalloids have been oxidized will be designated as Time ' T ' . A heat balance for the conversion process at Time 'T' may be expressed as follows.
(II) Q REACTT + Q CHARG + Q TRIMT = O
Where Q REACTT is the total heat o~ reaction within the metal at `
time 'T' and is determined by equation (XI) later explained. Q
CHARG is the heat content of the charge as introduced into the vessel and Q TRIM T is the heat energy either added to or taken from the molten metal by various factors associated with the conversion process.
Q TRIMT includes factors not materially dependent on the time at which determined and are summated as Q TRIMS. Other factors that are dependent on the time during the blow at which they are measured are summated as Q TRIM V.
(III) Q TRIMT = Q TRIM S + Q TRIM V
It has been found that Q TRIM S includes thermal heat losses, heat losses from metal slopping, heat losses from heat o~f fumes and heat ret~lned in the vessel from previous heats. Q TRIM S is determined by ' ' :
;
r - ~
71~i ; (IV) ~- Q TRIM S = Q NET + Q 5LP + Q FUME + Q RET
where Q TRIM S is the summated heat loss caused by net thermal loss (Q NET), heat losses from metal slopping (Q SLP), heat losses from fume (Q FUME) and the heat required in the vessel (Q RET).
It has been determined that Q TRIM S has a substantially constant value as, for example, -10,000,000 BTUs for a particular furnace.
Q TRIM V includes the heat required -to elevate the temperature of the lance oxygen to the base temperature at time 'T', the heat leaving with the carbon gases at time IT', the heat content of the bath at time 'T' and the heat content of the slag at time 'T' and is determined by the following equation:
(v) Q TRIM V = Q02TT - Q GASTT - Q BTT - Q SLGTT
Q02TT, the heat required to elevate the total amount of lance oxygen supplied to the conver-ter to the base temperature to time 'T' is determined from the following relationship (VI) Q02TT = -63.2 ~LO
where ~ 0 is the summated amount of lance oxygen fed to the converter from the beginning of the conversion process to the time 'T' and -63.2 is a constant.
Q GASTT is the heat lost with the carbon gases leaving the converter and is determined by (VII) Q GASTT = -4.53 ~VCQLV -7.5 VC02LV
where ~COLV is the summated total volume of carbon monoxide gas leaving the converter and ~VCO2LV is the summated volume of carbon dioxide leaving the converter to time 'T'.
,, ~ .~
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, r `- Q BTT is the heat content of the bath at time 'T' and is determined by (VIII) ` Q BTT = WBTT (AB + BBX) where WBTT is the weight of the molten meta:L bath at time 'T' and is determined by equation XXVII, later explained, AB is an addi-tive constant of the bath and BB is a temperature coefficient of : the bath and X is the temperature of the bath at time 'T'.
Q SLGTT, the heat content of the slag, is determined by (IX) Q SLGTT = WBLGTT (X -2,900) x SHSLG
where WSLGTT is the total weight of the slag at time 'T' and X
is the temperature of the molten metal at Time 'T', 2,900 is the base temperature and SHSLG is the specific heat of the slag.
Combining equations IV, VI, VII, VIII AND IX, the ~TRIMT may be expressed as follows:
(X) Q TRIMT = -10,000,000 - 63.2 ~LO
+4.53 VCOLV + 7.5 SVCO2LV
-WBTT (AB + BBX) -WSLGTT (X - 2,900) SHSLG
Q REACTT, the total heat of reaction within the metal at time 'T' is determined by the equation (XI) Q REACTT = Q REACT S + Q REACT V
where:
(XII) Q REACTS = QO2M ~ Q ~3Fe +
. , . . :
' ~ ' ' ,~
, . .
s~
: Q F2Fe -t O FlFe + Q CALCC
Q CALMC + Q H20B
and (XIII) Q REACT V = Q 02sT + CLTT -~
Q DUST + QMXSTT + QFeO
The variables in Q REACTS are Q02M, the heat released by metal-loids; Q F3Fe, the heat of reduction of Fe304; QF2Fe, the heat .
of reduction of Fe203; Q FlFe the heat of reduction of FeO, QCALCC, the heat of calcination of calcium carbonate; Q CALMC, the heat of calcination of magnesium carbonate and QH20B, the heat of vaporization of water.
Q02M, the heat released by the metalloids other than carbon, is determined by (XIV) Q02M = AVHFM x V02M
where V02M is the volume of oxygen that reacts with the metalloids to convert the metalloids to their oxides and AVHFM is the average heat of formation of all of the metalloids in the charge. V02M
is determined from the relation of the oxygen supplied to the vessel through the lance and the composition of the waste gases evolved and is determined by the following equation:
V02M = ~LO - VC02WG - V02WG -~ VCOWG
+ V02IN - 0~05 ~VC02WG - ~V02DA
where LO is the flow rate of the lance oxygen, VC02WG is the flow - rate of the carbon dioxide in the waste gas, V02WG is the flow rate of the oxygen in the waste gas, VCOWG is the flow rate of the carkon monoxide in the waste yas, V02IN is the flow rate of oxygen . .
- 12 ~
, . . . ..
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; by air infiltration and VCO2WG is the flow rate of the carbon dio- ..
xide in the waste gas and VO2DA is the flow rate of oxygen from air infiltration converted to dust.
The heat of reduction of Fe3O4 to Fe is determined by (XVI) QF3Fe = (WF3S + WF3CL) x FFEF3 where WF3S is the weight of the Fe3O4 from scrap, WF3Cl is the weight of Fe3O4 from the cold iron and FFEF3 is the heat of re-duction of Fe per pound of Fe3O4 at 2,900F.
The heat of reduction of Fe2O3 to Fe is determined by (XVII) QF2Fe = (WF2FC + WF2FA) x FFEF2 where WF2FC is the weight of the Fe2O3 from charge and WF2FA is the weight of the Fe2O3 from additions and FFEF2 is the heat of reduction of Fe per pound of Fe2O3 at 2,900F.
The heat of reduction of FeO to Fe is determined by (X~III) -QFlFe = ~WFlFC + WFlFA) x FFEFl where WFlFC is the weight of the FeO from the charge and WFlFA is the weight of the FeO from additions and FFEFl is the heat of reduction of Fe per pound of E'eO at 2,900F. .- -(XIX) . .Q CALCC = WCCFE + WCCFA x F CALCC
where WCCFC is the wei~ht of the calcium carbonate from the charge, WCCFA is the weight of the calcium carbonate from additions and F CALCC is th~ heat of calcination of CaO per pound of calcium carbonate at 1,623F.
( XX) C CALMC = (WMC~C + WMCFA) x FCALMC
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.. . .
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,, ~ ~CJ356~8~
where MCFC is the weight of MgC03 from charge and WMCFA is the weight of the MgC03 from addition and FCALMC is -the calcination of MgO per pound of MgG03.
; (XXI) Q H20B = WH20s (AH20) + BH20 x TH~I) where WH20B is the weight of the water vaporized, AH20 is an additive constant and BH20 is a temperature coefficient constant and TH~ is the temperature of the hot metal.
The factors of Q REACT V as expressed in equation XIII
are determined as follows:
(XXII) QO 2BT = 0.0031 x WBTT x FSOL02 CCBT
where Q02BT is the heat oE oxygen in solution and WBTT is the weight oE the bath at time 'T' t and FSOLO 2 is the heat of solutioni of oxygen in iron and CCBT is the carbon content of the molten metal bath at time 'T'.
The summated hea~ release from carbon QCLTT is determined by (XXIII) QCLTT = 0.0316 VCOLV x FCOC
~ 0.0316 ~YC02LV x FC02C
where FCOC is the heat of formation of carbon monoxide per pound carbon and FC02C is the heat of formation of carbon dioxide per pound carbon and VCOLV is volume rate of carbon monoxide from the vessel and VC02LV is volume flow rate o:E carbon dioxide from the vessel.
~ DUST, which is the heat carried away with the dust, is determined by the equation:
~, '': ' , , , . ~
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. .
.
:
. . .
~5~7~6 (XXIV) Q DUST = 3 OVC02WG
where VCO2WG is the flow rate of carbon dioxide inthe waste gas and 30 is the conversion constant.
QMXSTT is the total heat release in the slag to time 'T' and is determined by (XXV) QMXSTT = WSLGTT x FMXSI
where WSLGTT is the total weight of the slag at time 'T' and ; 10 FMXSI is the heat release per pound of slag.
QFeO, the heat release in FeO formation is determined by (XXVI) QFeO = 604 VO2Fel where VO2Fel is the volume of oxygen to form FeO in the slag and 604 is a conversion constant.
WBTT, the weight of the molten metal bath at time 'T' is determined from the following equation:
(XXVII) WBTT = WHM + WS - WSILT - WMNLT - WPLT
- WCRLT - WTILT - WSLT
- 0.276VO2Fel - 0.018 ~VCO2WG
- 0.0316 ~VCO2WG - 0.0316 ~VCOWG
where WHM is the weight of the hot metal, WS is the weight of the scrap and WSILT is the weight of the silicon leaving the metal bath, WMNLT is the weight of the manganese leaving the metal bath, WPLT is the weight of the phosphorus leaving the metal bath, WCRLT
is the weight of the chome leaving the metal bath, WTILT is the weight of the titanium leaving the metal bath, WSLT is the weight of the sulphur leaving the bath, 0.276 VO2Fel is the iron loss to ,............................... . .
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. `
~Ld[1~5~7~
-- the slag and 0.018 ~VCO2WG is the iron loss to dust, 0.0316 VCO2WG is the carbon loss as carbon dioxide and 0.0316 VCOWG
is the carbon loss as carbon monoxide.
; VO2Fel is the volume of oxygen combining with iron in the bath to form the FeO in the slag and is determined as follows-(XXVIII) VO2Fel = ~O - VO2M - ~ CO2WG - VCOWG
- VO2WG - 0.05 VCO2WG
- O.0366 WBTT -~VO2DA
CBTT
where WBTT is the weight of the molten metal bath at time 'T' and CBTT is the carbon content of the bath at time 'T'.
Solving the above for Q REACTT and substituting the elements of the QTRIMT equation in heat balance equation II and solving for X, the temperature of the bath at time 'T', the following equation is obtained:
(XXIX) X = (Q REACTT + Q CHARG - 10,000,000 - 63.2 LO + 4.53 VCOLV -~ 7.5 ~VCO2LV
- WBTT(AB) + 2900. SHSLG. WSLGTT) (WBTT.BB + SHSLG~ WSLGTT) The weight of the slag in the bath at any time 'T' is WSLGTT and is determined by the following:
(XXX) WSLGTT = WSLGS + 0.362 VO2Fel where WSLGS
= 0.977 WLCM + 0.996 WDLCM + 0.993 WSPCM
- -~ 2.14 WSILT + 1.291 WMNLT ~ 1.516 WPLT
+ 1.46 WCRLT + 1.667 WTILT
, .. . .
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WLCM is the weight of line charge and WDLCM is the weight of dolomite charged and WDPCM is the weight of flurspar charged, their respective slag constants 0.977, 0.966 and 0.933 are de-termined from their respective analyses.
The weight of the FeO in the slag is determined as follows:
(XXXI) WFeO = 0.362V02 Fel Where it is desired to obtain the FeO percentage in the slag at time IT', this is determined as follows:
(XXXII) Percent FeO in slag =0.362V02Fel x_100 WSLGS ~ ~.362 V02 Fel It will be apparent from the above relationship be-tween the weights of the constituents in the charge, the amount of oxygen supplied to the bath through the lance and the amount of carbon monoxide and carbon dioxide leaving the vessel determined by the amount of carbon monoxide and carbon dioxide in the waste gas, both the temperature of the molten metal bath and the amount of FeO formed in the slag can be continuously determined after substantially all of the metalloids have been converted to their oxides.
Thus, the temperature of the molten metal bath and the amount of FeO fbrmed in the slag can be continuously determined without any direct temperature measurement of the molten metal bath during the conversion process. This eliminates the inaccuracies that may be encountered due to inaccurate temperature measurements.
The temperature may also be determined without a sampling and anal-ysis of the hot metal either fed to the converter or in the ~, . ~ . . ~ .
, :
. .
:' " ,, ' , . ~ ' :
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converter during the conversion process. This eliminates the in-accuracies due to errors in metal analysis and also eliminates turn-down during the conversion process. Also, the herein described process does not require an analysis of the charge for the carbon content and thus, eliminates possible errors due to inaccurate car-bon analysis.
According to the provisions of the patent statutes, the principle, preferred construction and mode of operation of this invention has been illustrated and described with what is now con-sidered to represent its best embodiment.
", , ~ , . , , ,, ' .: , . : . , ' '. - ; : ~ :
~L~S0786 temperature determinations. The final temperature of the molten metal bath at the end of the conversion process is determined by adding to the initial measured temperature of the bath, the temp-erature increase attributable to the oxy~en consumed in the con-version process. The accuracy of the calculated temperature at turndown is dependent on the accuracy of the initial measured - 3a -~.
.~ . . . . . . .
, ~ I . . . .
. , - . . : .
, `` lL~SC3'7~36 temperature by the thermocouple.
It is well known that there is a temperature gradient within molten metal bath with the highest temperature .in the jet oxygen-hot metal reaction zone. It is also feasible that the slag formed during the conversion process is at a differential temperature to that of the molten metal. These ~actors affect the accuracy of determining an accurate initial measured temperature and therefore, also affect the accuracy of the calculated temperature at turndownO
Another proposed procedure for determining the temper-: 10 ature of the bath is disclosed in United States patent 3,489/518, granted on January 13, 1970, and entitled "Carbon Determination Method And Apparatus". In this process, the amount of carbon in : the charge material is first determined and the other constituents of the charge are also conventionally sampled and analyzed for heat release determination. The increase in the temperature of the molten metal bath attributable to the oxidation of the metalloids is determined by calculating the heat of formation of each of the metalloids and the heat of formation of the gaseous carbon compounds.
One of the inherent deficiencies in this method is the necessity of accurately sampling prior to analyzing the charge for the metalloidconstituents. An error in the sampling or analysis of one of the metalloids results in a -temperature error equivalent to the error in the weight of metalloid multiplied by the heat of formation of the particular metalloid.
SUMMARY O~ THE INVENTION
According to the present invention, the tempera~ure of the molten metal bath is determined by measuring the total amount of lance oxygen fed to the converter, the portion of the lance oxygen that is converted to oxides of carbon, the portion of the ::Lal 5~7~
lance oxygen that is converted to oxides of metalloicls and the portion of the lance oxygen used to oxidize the iron in the dust.
The heat added to the molten metal bath by the oxidation of the `
carbon is determined from the heat of formation of the carbon containing gases and the heat added by the oxidation of the metalloids is determined from the average heat of formation per unit volume of oxygen to convert the metalloids to their oxides.
At a preselected time during the conversion process, after sub-stantially all of the metalloids have been oxidized, the temper-ature of the molten metal bath is determined from the total heatadded to the molten metal bath by the oxidation of the metalloids and the heat added to the bath by the oxidation of the portion of the carbon during the conversion process up to the preselected time.
After the conversion process has progressed beyond the oxidation of the metalloids, the further increase in the temper-ature of the molten metal bath is determined from the portion of the lance oxygen that is subsequently converted to oxides of carbon in a similar manner. During the latter stages of the conversion process, the increasing volume of oxyyen that reacts with the iron to form FeO is measured and the heat added to the molten metal bath by the FeO formation is determined. With the above information, the increasiny weight of the slag in the molten metal bath and the decreasing weight of the molten bath may also be determined.
To determine the temperature of the molten metal bath in aocordance with the present invention, all that is required is to determine the heat content of the charge, the amount of oxygen fed to the converter and a continuous analysis of the gases evolved .
. . ' , ::
: , ~6195~78~
~ during the conversion process. The present invention eliminates the necessity of making a direct temperature measurement of the molten metal bath, as by a thermocouple or t:he like, determining the carbon content of the charge by analysis or sampling and analyzing the hot metal fed -to the converter.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a graphical illustra-tion of the amount of oxygen supplied to the converter by the oxy~en lance and that portion of the lance oxygen that reacts with the carbon to form carbon containing gases and the portion that reacts with the metalloids to form metalloid oxides and the portion of the oxygen that reacts with the iron to form FeO.
Figure 2 is another graphical illustration of the con-version of the lance oxygen to the carbon containiny gases, metal- i loid oxides and ~eO and that required portion of the oxygen that infiltrates with the air in-to the flue to convert the carbon mono-xide to carbon dioxide in the flue.
DESCRIPTION OF THE PR~FERRED EMBODIMENT
In order to practice the hereinafter described process, it is necessary to have gas analyzers capable of measuring the constituents of the waste gas and to transmit this information to a computer. The computer is suitably programmed to determine from the waste or "off" gas in the flue, the composition of the gas leaving the converter before it is admixed and combusted with in-filtrating air. Other instrumentation is necessary to determine the rate of flow of oxygen through the lance, and the wei~ht, temperature and analysis of the charge. Suita~le apparatus for analyzing the waste or "off'; gas for determining the gases leaving the vessel is disclosed and described in United States patent ' ,," ~, ' " ' .
-~ 5~78~;
3,489,518, entitled "Carbon Determination Method and Apparatus".
It should be understood, however, that other apparatus may be employed to analyze the gases and transmit this information to a computer.
All temperature calculations are preferably taken at a base temperature of 2,900F. and it will be hereinafter assumed that the heat content of the various constituents at 2,900F. is zero, although any base temperature, such as ambient, may be ; employed.
To determine the temperature of the molten metal bath, the total heat content of the charge, QCHARG, is first determined from a summation of the heat content of each of the constituents of the charge according to the following:
Q CHARG = QHM + QS + QCIC + QLCM
~ Q DLC + QSPCM + QSTC
Where QHM is the heat content of the hot metal; QHM is determined by the temperature and weight of the hot metal introduced into the converter; QS is the heat content of the scrap; QCIC is the heat content of the cold iron and QLCM the heat content of the lime in the charge; Q DLC is the heat content of the dolomite in the charge and QSPCM is the heat content of the spar in the charge and QSTC is the heat content of the stone in the charge. QS; QCIC;
QLCM; QDLC; QSPCM and QSTC are determined by the weight and temper-ature of the constituents introduced into the converter.
After the total heat content of the charge, calculated from a base of 2,900F.,~ is determined, the material is charged into a top blown oxygen converter and an oxygen lance is lowered ;
into the converter. The conversion process is initiated by . . ~ . . .. .
: . -' -' ~
~s~
supplying oxygen through the lance into the charge within theconverter. The rate of flow of oxygen through the lance is main-tained relatively constant at, for example, as illustrated in Figures 1 and 2, a rate of 15,000 SCFM. The rate oE flow of oxygen is continually measured and this information is transmitted to the computer.
The waste or "off" gas from the converter is continually measured from the beginning of the conversion process and this information is periodically supplied to a computer. The computer, from the composition of the waste gas in the flue, determines through a suitable program, the volume and composition of the gases leaving the converter before the gases are admixed with the air of infiltration. The gases leaving the converter during the conversion process, where su~stantially all of the oxygen fed by the lance reacts with the materials in the molten metal bath, consists of carbon monoxide and carbon dioxide. A substantial portion or at times, all of the carbon monoxide after leaving the vessel combines with the oxygen of the infiltrating air and is converted to carbon dioxide. The periodically measured amounts of carbon monoxide and carbon dioxide leaving the vessel and the periodically measured amounts of oxygen supplied through the lance are continually summated and recorded by the computer, After the conversion process has progressed for a sufficient period of time for the metalloids, i.e. silicon, man-ganese/ phosphorus, cobalt, titanium and the like, to be oxidized, the summated amount of oxygen supplied through the lance and the summated amounts of carbon monoxide and carbon dioxide in the gases leaving the converter are determined~ As is illustrated in Figures 1 and 2, after a conventional conversion process has progressed for ,. -, ~ , ,, ' .
~sla 7~
a period of about 10 minutes, with due allowance for oxidized iron, substantially all of the lance oxygen is converted to carbon mono-xide and carbon dioxide and substantially all of the metalloids have been oxidized so that little, if any oxygen is being consumed after the conversion process has progressed for a period of 10 minutes for the oxidation of the metalloids.
For convenience, the time at which the temperature of the bath is determined after the metalloids have been oxidized will be designated as Time ' T ' . A heat balance for the conversion process at Time 'T' may be expressed as follows.
(II) Q REACTT + Q CHARG + Q TRIMT = O
Where Q REACTT is the total heat o~ reaction within the metal at `
time 'T' and is determined by equation (XI) later explained. Q
CHARG is the heat content of the charge as introduced into the vessel and Q TRIM T is the heat energy either added to or taken from the molten metal by various factors associated with the conversion process.
Q TRIMT includes factors not materially dependent on the time at which determined and are summated as Q TRIMS. Other factors that are dependent on the time during the blow at which they are measured are summated as Q TRIM V.
(III) Q TRIMT = Q TRIM S + Q TRIM V
It has been found that Q TRIM S includes thermal heat losses, heat losses from metal slopping, heat losses from heat o~f fumes and heat ret~lned in the vessel from previous heats. Q TRIM S is determined by ' ' :
;
r - ~
71~i ; (IV) ~- Q TRIM S = Q NET + Q 5LP + Q FUME + Q RET
where Q TRIM S is the summated heat loss caused by net thermal loss (Q NET), heat losses from metal slopping (Q SLP), heat losses from fume (Q FUME) and the heat required in the vessel (Q RET).
It has been determined that Q TRIM S has a substantially constant value as, for example, -10,000,000 BTUs for a particular furnace.
Q TRIM V includes the heat required -to elevate the temperature of the lance oxygen to the base temperature at time 'T', the heat leaving with the carbon gases at time IT', the heat content of the bath at time 'T' and the heat content of the slag at time 'T' and is determined by the following equation:
(v) Q TRIM V = Q02TT - Q GASTT - Q BTT - Q SLGTT
Q02TT, the heat required to elevate the total amount of lance oxygen supplied to the conver-ter to the base temperature to time 'T' is determined from the following relationship (VI) Q02TT = -63.2 ~LO
where ~ 0 is the summated amount of lance oxygen fed to the converter from the beginning of the conversion process to the time 'T' and -63.2 is a constant.
Q GASTT is the heat lost with the carbon gases leaving the converter and is determined by (VII) Q GASTT = -4.53 ~VCQLV -7.5 VC02LV
where ~COLV is the summated total volume of carbon monoxide gas leaving the converter and ~VCO2LV is the summated volume of carbon dioxide leaving the converter to time 'T'.
,, ~ .~
-: f .~
, r `- Q BTT is the heat content of the bath at time 'T' and is determined by (VIII) ` Q BTT = WBTT (AB + BBX) where WBTT is the weight of the molten meta:L bath at time 'T' and is determined by equation XXVII, later explained, AB is an addi-tive constant of the bath and BB is a temperature coefficient of : the bath and X is the temperature of the bath at time 'T'.
Q SLGTT, the heat content of the slag, is determined by (IX) Q SLGTT = WBLGTT (X -2,900) x SHSLG
where WSLGTT is the total weight of the slag at time 'T' and X
is the temperature of the molten metal at Time 'T', 2,900 is the base temperature and SHSLG is the specific heat of the slag.
Combining equations IV, VI, VII, VIII AND IX, the ~TRIMT may be expressed as follows:
(X) Q TRIMT = -10,000,000 - 63.2 ~LO
+4.53 VCOLV + 7.5 SVCO2LV
-WBTT (AB + BBX) -WSLGTT (X - 2,900) SHSLG
Q REACTT, the total heat of reaction within the metal at time 'T' is determined by the equation (XI) Q REACTT = Q REACT S + Q REACT V
where:
(XII) Q REACTS = QO2M ~ Q ~3Fe +
. , . . :
' ~ ' ' ,~
, . .
s~
: Q F2Fe -t O FlFe + Q CALCC
Q CALMC + Q H20B
and (XIII) Q REACT V = Q 02sT + CLTT -~
Q DUST + QMXSTT + QFeO
The variables in Q REACTS are Q02M, the heat released by metal-loids; Q F3Fe, the heat of reduction of Fe304; QF2Fe, the heat .
of reduction of Fe203; Q FlFe the heat of reduction of FeO, QCALCC, the heat of calcination of calcium carbonate; Q CALMC, the heat of calcination of magnesium carbonate and QH20B, the heat of vaporization of water.
Q02M, the heat released by the metalloids other than carbon, is determined by (XIV) Q02M = AVHFM x V02M
where V02M is the volume of oxygen that reacts with the metalloids to convert the metalloids to their oxides and AVHFM is the average heat of formation of all of the metalloids in the charge. V02M
is determined from the relation of the oxygen supplied to the vessel through the lance and the composition of the waste gases evolved and is determined by the following equation:
V02M = ~LO - VC02WG - V02WG -~ VCOWG
+ V02IN - 0~05 ~VC02WG - ~V02DA
where LO is the flow rate of the lance oxygen, VC02WG is the flow - rate of the carbon dioxide in the waste gas, V02WG is the flow rate of the oxygen in the waste gas, VCOWG is the flow rate of the carkon monoxide in the waste yas, V02IN is the flow rate of oxygen . .
- 12 ~
, . . . ..
: ~ , 7~
; by air infiltration and VCO2WG is the flow rate of the carbon dio- ..
xide in the waste gas and VO2DA is the flow rate of oxygen from air infiltration converted to dust.
The heat of reduction of Fe3O4 to Fe is determined by (XVI) QF3Fe = (WF3S + WF3CL) x FFEF3 where WF3S is the weight of the Fe3O4 from scrap, WF3Cl is the weight of Fe3O4 from the cold iron and FFEF3 is the heat of re-duction of Fe per pound of Fe3O4 at 2,900F.
The heat of reduction of Fe2O3 to Fe is determined by (XVII) QF2Fe = (WF2FC + WF2FA) x FFEF2 where WF2FC is the weight of the Fe2O3 from charge and WF2FA is the weight of the Fe2O3 from additions and FFEF2 is the heat of reduction of Fe per pound of Fe2O3 at 2,900F.
The heat of reduction of FeO to Fe is determined by (X~III) -QFlFe = ~WFlFC + WFlFA) x FFEFl where WFlFC is the weight of the FeO from the charge and WFlFA is the weight of the FeO from additions and FFEFl is the heat of reduction of Fe per pound of E'eO at 2,900F. .- -(XIX) . .Q CALCC = WCCFE + WCCFA x F CALCC
where WCCFC is the wei~ht of the calcium carbonate from the charge, WCCFA is the weight of the calcium carbonate from additions and F CALCC is th~ heat of calcination of CaO per pound of calcium carbonate at 1,623F.
( XX) C CALMC = (WMC~C + WMCFA) x FCALMC
~, - ï3 -. ' . - ' .
.. . .
,, : .. ~ , ;
' ' ' ''''' . . , ' ' ~' ' .,.., .
,, ~ ~CJ356~8~
where MCFC is the weight of MgC03 from charge and WMCFA is the weight of the MgC03 from addition and FCALMC is -the calcination of MgO per pound of MgG03.
; (XXI) Q H20B = WH20s (AH20) + BH20 x TH~I) where WH20B is the weight of the water vaporized, AH20 is an additive constant and BH20 is a temperature coefficient constant and TH~ is the temperature of the hot metal.
The factors of Q REACT V as expressed in equation XIII
are determined as follows:
(XXII) QO 2BT = 0.0031 x WBTT x FSOL02 CCBT
where Q02BT is the heat oE oxygen in solution and WBTT is the weight oE the bath at time 'T' t and FSOLO 2 is the heat of solutioni of oxygen in iron and CCBT is the carbon content of the molten metal bath at time 'T'.
The summated hea~ release from carbon QCLTT is determined by (XXIII) QCLTT = 0.0316 VCOLV x FCOC
~ 0.0316 ~YC02LV x FC02C
where FCOC is the heat of formation of carbon monoxide per pound carbon and FC02C is the heat of formation of carbon dioxide per pound carbon and VCOLV is volume rate of carbon monoxide from the vessel and VC02LV is volume flow rate o:E carbon dioxide from the vessel.
~ DUST, which is the heat carried away with the dust, is determined by the equation:
~, '': ' , , , . ~
,,. ~ : .:
. .
.
:
. . .
~5~7~6 (XXIV) Q DUST = 3 OVC02WG
where VCO2WG is the flow rate of carbon dioxide inthe waste gas and 30 is the conversion constant.
QMXSTT is the total heat release in the slag to time 'T' and is determined by (XXV) QMXSTT = WSLGTT x FMXSI
where WSLGTT is the total weight of the slag at time 'T' and ; 10 FMXSI is the heat release per pound of slag.
QFeO, the heat release in FeO formation is determined by (XXVI) QFeO = 604 VO2Fel where VO2Fel is the volume of oxygen to form FeO in the slag and 604 is a conversion constant.
WBTT, the weight of the molten metal bath at time 'T' is determined from the following equation:
(XXVII) WBTT = WHM + WS - WSILT - WMNLT - WPLT
- WCRLT - WTILT - WSLT
- 0.276VO2Fel - 0.018 ~VCO2WG
- 0.0316 ~VCO2WG - 0.0316 ~VCOWG
where WHM is the weight of the hot metal, WS is the weight of the scrap and WSILT is the weight of the silicon leaving the metal bath, WMNLT is the weight of the manganese leaving the metal bath, WPLT is the weight of the phosphorus leaving the metal bath, WCRLT
is the weight of the chome leaving the metal bath, WTILT is the weight of the titanium leaving the metal bath, WSLT is the weight of the sulphur leaving the bath, 0.276 VO2Fel is the iron loss to ,............................... . .
., , : , , . ' . : ' , ., :
' ` ' '', ' , ''',, . ',~'~'. '' ': . ' :. ' , , ` ' ' ' ' ' ~ ' ' ' ~ . ':
. `
~Ld[1~5~7~
-- the slag and 0.018 ~VCO2WG is the iron loss to dust, 0.0316 VCO2WG is the carbon loss as carbon dioxide and 0.0316 VCOWG
is the carbon loss as carbon monoxide.
; VO2Fel is the volume of oxygen combining with iron in the bath to form the FeO in the slag and is determined as follows-(XXVIII) VO2Fel = ~O - VO2M - ~ CO2WG - VCOWG
- VO2WG - 0.05 VCO2WG
- O.0366 WBTT -~VO2DA
CBTT
where WBTT is the weight of the molten metal bath at time 'T' and CBTT is the carbon content of the bath at time 'T'.
Solving the above for Q REACTT and substituting the elements of the QTRIMT equation in heat balance equation II and solving for X, the temperature of the bath at time 'T', the following equation is obtained:
(XXIX) X = (Q REACTT + Q CHARG - 10,000,000 - 63.2 LO + 4.53 VCOLV -~ 7.5 ~VCO2LV
- WBTT(AB) + 2900. SHSLG. WSLGTT) (WBTT.BB + SHSLG~ WSLGTT) The weight of the slag in the bath at any time 'T' is WSLGTT and is determined by the following:
(XXX) WSLGTT = WSLGS + 0.362 VO2Fel where WSLGS
= 0.977 WLCM + 0.996 WDLCM + 0.993 WSPCM
- -~ 2.14 WSILT + 1.291 WMNLT ~ 1.516 WPLT
+ 1.46 WCRLT + 1.667 WTILT
, .. . .
: , . .: . , ' ~
1~5~
WLCM is the weight of line charge and WDLCM is the weight of dolomite charged and WDPCM is the weight of flurspar charged, their respective slag constants 0.977, 0.966 and 0.933 are de-termined from their respective analyses.
The weight of the FeO in the slag is determined as follows:
(XXXI) WFeO = 0.362V02 Fel Where it is desired to obtain the FeO percentage in the slag at time IT', this is determined as follows:
(XXXII) Percent FeO in slag =0.362V02Fel x_100 WSLGS ~ ~.362 V02 Fel It will be apparent from the above relationship be-tween the weights of the constituents in the charge, the amount of oxygen supplied to the bath through the lance and the amount of carbon monoxide and carbon dioxide leaving the vessel determined by the amount of carbon monoxide and carbon dioxide in the waste gas, both the temperature of the molten metal bath and the amount of FeO formed in the slag can be continuously determined after substantially all of the metalloids have been converted to their oxides.
Thus, the temperature of the molten metal bath and the amount of FeO fbrmed in the slag can be continuously determined without any direct temperature measurement of the molten metal bath during the conversion process. This eliminates the inaccuracies that may be encountered due to inaccurate temperature measurements.
The temperature may also be determined without a sampling and anal-ysis of the hot metal either fed to the converter or in the ~, . ~ . . ~ .
, :
. .
:' " ,, ' , . ~ ' :
.' . ., ~ . . , - .
~S~t7BqEI;
converter during the conversion process. This eliminates the in-accuracies due to errors in metal analysis and also eliminates turn-down during the conversion process. Also, the herein described process does not require an analysis of the charge for the carbon content and thus, eliminates possible errors due to inaccurate car-bon analysis.
According to the provisions of the patent statutes, the principle, preferred construction and mode of operation of this invention has been illustrated and described with what is now con-sidered to represent its best embodiment.
", , ~ , . , , ,, ' .: , . : . , ' '. - ; : ~ :
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for determining the heat content of a molten metal bath in a top blown oxygen converter at a preselected time during the conversion process after oxidation of substantially all of the metalloids in the molten metal bath and before the completion of the conversion process without utilizing direct temperature measurement of the molten metal bath comprising, a) determining the heat content of the charge introduced into the converter without determining the carbon content of the charge, b) determining the total heat of reaction of the molten metal bath from the beginning of the conversion process to a pre-selected time during the conversion process after oxidation of substantially all of the metalloids in the molten metal bath and prior to the completion of the conversion process, c) determining the total heat loss of the molten metal bath from the beginning of the conversion process to said pre-selected time from factors associated with the conversion process, and d) obtaining the heat content of the molten metal bath at said preselected time by summating the heat content of the charge, the total heat of reaction of the molten metal and the total heat loss from factors associated with the conversion process from the beginning of the conversion process to said preselected time during the conversion process.
2. A method for determining the heat content of a molten metal bath in a top blown oxygen converter at said preselected time during the conversion process as set forth in claim 1 which includes, a) determining the heat content of the hot metal, b) determining the heat content of the scrap, c) determining the heat content of the cold iron, d) determining the heat content of the lime in the charge, e) determining the heat content of the dolomite in the charge, f) determining the heat content of the spar in the charge, g) determining the heat content of the stone in the charge, h) determining from the foregoing determinations the heat content of the charge from the expression QCHARG = QHM + QS + QCIC + QLCM
+ QSLC + QSPCM + QSTC
QCHARG = the heat content of the charge, QHM = the heat content of hot metal, QS = the heat content of the scrap, QCIC = the heat content of the cold iron, QLCM = the heat content of the lime in the charge, QDLC = the heat content of the dolomite in the charge, QSPCM = the heat content of the spar in the charge, QSTC = the heat content of the stone in the charge.
+ QSLC + QSPCM + QSTC
QCHARG = the heat content of the charge, QHM = the heat content of hot metal, QS = the heat content of the scrap, QCIC = the heat content of the cold iron, QLCM = the heat content of the lime in the charge, QDLC = the heat content of the dolomite in the charge, QSPCM = the heat content of the spar in the charge, QSTC = the heat content of the stone in the charge.
3. A method for determining the heat content of a molten metal bath in a top blown oxygen converter at said preselected time during the conversion process as set forth in claim l which includes, a) determining the net thermal loss in the vessel, b) determining the heat loss from metal slopping, c) determining the heat loss from fumes, d) determining the heat retained in the vessel from the previous conversion process, e) determining from a base temperature the heat required to elevate total amount of lance oxygen supplied to the converter from the beginning of the conversion process to said preselected time, f) determining from a base temperature the heat lost with the carbon gases leaving the converter from the beginning of the conversion process to said preselected time, g) determining the weight of the molten metal bath at said preselected time, h) determining the heat content of the molten metal bath at said preselected time, i) determining the heat content of the slag at said pre-selected time, and j) obtaining the heat losses of the molten metal bath from the beginning of the conversion process to said preselected time from factors associated with said conversion process from the expression Q TRIM T = Q NET + Q SLP + Q FUME + QO2TT
- Q GASTT - QBTT - QSLGTT
where:
Q TRIM T = the total heat loss of the molten metal bath from the beginning of the conversion process to said preselected time from factors associated with the conversion process, Q NET = net thermal loss, Q SLP = heat loss from metal slopping, Q FUME = heat loss from fumes, Q RET = heat retained in the vessel from previous conversion processes, Q ?2TT = Heat required to elevate the total amount of lance oxygen supplied to the converter to the base temperature, Q GASTT = heat lost with the carbon gases leaving the con-verter, Q BTT = heat content of the bath at said predetermined time where QBTT is determined from the expression QBTT = WBTT (AB + BBX) where WBTT = weight of the molten metal bath at said predetermined time, AB = constant BB = constant X = the temperature of the bath at said predetermined time, and Q SLGTT = heat content of the slag at said predetermined time.
- Q GASTT - QBTT - QSLGTT
where:
Q TRIM T = the total heat loss of the molten metal bath from the beginning of the conversion process to said preselected time from factors associated with the conversion process, Q NET = net thermal loss, Q SLP = heat loss from metal slopping, Q FUME = heat loss from fumes, Q RET = heat retained in the vessel from previous conversion processes, Q ?2TT = Heat required to elevate the total amount of lance oxygen supplied to the converter to the base temperature, Q GASTT = heat lost with the carbon gases leaving the con-verter, Q BTT = heat content of the bath at said predetermined time where QBTT is determined from the expression QBTT = WBTT (AB + BBX) where WBTT = weight of the molten metal bath at said predetermined time, AB = constant BB = constant X = the temperature of the bath at said predetermined time, and Q SLGTT = heat content of the slag at said predetermined time.
4. A method for determining the heat content of a molten metal bath in a top blown oxygen converter at said preselected time during the conversion process as set forth in claim 1 which includes, a) determining the amount of lance oxygen fed to the con-verter from the beginning of the conversion process to said pre-selected time, b) determining the total volume of carbon monoxide leaving the converter from the beginning of the conversion process to said preselected time, c) determining the weight of the molten metal bath, d) determining the temperature of the molten metal bath, e) determining the weight of the slag in the molten metal bath at said preselected period of time, f) from the foregoing determinations determining the total heat loss of the molten metal bath from the beginning of the conversion process to said preselected time from factors associated with the conversion process from the expression Q TRIM T =
-10,000,000 = QO2TT - Q GASTT - Q BTT - Q SLGTT where:
Q TRIM T = the total heat loss from factors associated with the conversion process, QO2TT = the heat required to elevate the total amount of lance oxygen supplied to the converter to the base temperature and is determined from the expression QO2tt = -63.2 LO
where:
LO = summated amount of lance oxygen fed to the converter from the beginning of the conversion process to time 'T', -63.2 = conversion constant Q GASTT = heat lost from carbon gases leaving the converter and is determined from the following expression Q GASTT = -4.53 VCOLV -7.5 VCO2LV
where:
VCOLV = summated total volume of carbon monoxide, VCO2LV = summated volume of carbon dioxide, -4.53 = conversion constant for carbon monoxide, -7.5 = conversion constant for carbon dioxide, QBTT = heat content of the molten metal bath at said predetermined time and is determined from the expression QBTT = WBTT (AB = BBX) where:
ABTT = weight of the molten metal at said predetermined time AB = constant BB = constant X = temperature of the molten metal bath at said predetermined time QSLGTT = heat content of the slag at said pre-selected time and is determined from the expression Q SLGTT = WSLGTT (X -2,900) x SHSLG
where:
WSLGTT = total weight of the slag at said predetermined time, X = temperature of the molten metal at said predetermined time, 2,900°F = base temperature, SHSLG = specific heat of the slag.
-10,000,000 = QO2TT - Q GASTT - Q BTT - Q SLGTT where:
Q TRIM T = the total heat loss from factors associated with the conversion process, QO2TT = the heat required to elevate the total amount of lance oxygen supplied to the converter to the base temperature and is determined from the expression QO2tt = -63.2 LO
where:
LO = summated amount of lance oxygen fed to the converter from the beginning of the conversion process to time 'T', -63.2 = conversion constant Q GASTT = heat lost from carbon gases leaving the converter and is determined from the following expression Q GASTT = -4.53 VCOLV -7.5 VCO2LV
where:
VCOLV = summated total volume of carbon monoxide, VCO2LV = summated volume of carbon dioxide, -4.53 = conversion constant for carbon monoxide, -7.5 = conversion constant for carbon dioxide, QBTT = heat content of the molten metal bath at said predetermined time and is determined from the expression QBTT = WBTT (AB = BBX) where:
ABTT = weight of the molten metal at said predetermined time AB = constant BB = constant X = temperature of the molten metal bath at said predetermined time QSLGTT = heat content of the slag at said pre-selected time and is determined from the expression Q SLGTT = WSLGTT (X -2,900) x SHSLG
where:
WSLGTT = total weight of the slag at said predetermined time, X = temperature of the molten metal at said predetermined time, 2,900°F = base temperature, SHSLG = specific heat of the slag.
5. A method for determining the heat content of a molten metal bath in a top blown oxygen converter at said preselected time during the conversion process as set forth in claim 1 which includes, a) determining the heat released by the metalloids, b) determining the total heat of reduction of Fe3O4 to Fe in the molten metal bath, c) determining the total heat of reduction of Fe2O3 to Fe in the molten metal bath, d) determining the total heat of reduction of FeO in the molten metal bath, e) determining the total heat of calcination of calcium carbonate, f) determining the total heat of calcination of magnesium carbonate, g) determining the total heat of vaporization of water, h) determining the heat of oxygen in solution, i) determining the heat release from the carbon converted to carbon monoxide and carbon dioxide, j) determining the heat removed with the dust during the conversion process, k) determining the heat released in the slag from the beginning of the conversion process to said preselected time, 1) determining the heat released in the formation of FeO in the slag, and m) determining the heat of reaction of the molten metal bath from the beginning of the conversion process to said pre-selected time during the conversion process from the expression Q REACTT = QO2M + QF3Fe + QF2Fe + QF1Fe + Q CALCC
+ QCALMC + QH2OB + QO2BT + QCLTT + QDUST
+ QMXSTT + QFeO
where Q REACTT = total heat of reaction of the molten metal bath from the beginning of the conversion process to said preselected time during the conversion process, QO2M = heat released by the metalloids, QF3Fe = heat of reduction of Fe3O4 to Fe, OF2Fe = heat of reduction of Fe2O3 to Fe, QF1Fe = heat of reduction of FeO to Fe, QCALCC = heat of calcination of calcium carbonate, QCALMC = heat of calcination of magnesium carbonate, QH2OB = heat of vaporization of water, QO2BT = heat of oxygen in solution, QCLTT = heat released by conversion of carbon to carbon monoxide and carbon dioxide, QDUST = heat removed from said converter as dust, QMXSTT = heat release in the slag from beginning of the conversion process to said pre-selected time, QFeO = heat release in the formation of FeO.
+ QCALMC + QH2OB + QO2BT + QCLTT + QDUST
+ QMXSTT + QFeO
where Q REACTT = total heat of reaction of the molten metal bath from the beginning of the conversion process to said preselected time during the conversion process, QO2M = heat released by the metalloids, QF3Fe = heat of reduction of Fe3O4 to Fe, OF2Fe = heat of reduction of Fe2O3 to Fe, QF1Fe = heat of reduction of FeO to Fe, QCALCC = heat of calcination of calcium carbonate, QCALMC = heat of calcination of magnesium carbonate, QH2OB = heat of vaporization of water, QO2BT = heat of oxygen in solution, QCLTT = heat released by conversion of carbon to carbon monoxide and carbon dioxide, QDUST = heat removed from said converter as dust, QMXSTT = heat release in the slag from beginning of the conversion process to said pre-selected time, QFeO = heat release in the formation of FeO.
6. A method for determining the heat content of a molten metal bath in a top blown oxygen converter at said preselected time during the conversion process as set forth in claim 5 which includes, a) determining the volume of oxygen that reacts with the metalloids to convert the metalloids to their oxides, and b) determining from the foregoing determination the heat released by the metalloids other than carbon from the expression QO2M = AVHFM x VO2M
where:
QO2M = heat released by the metalloids, AVHFM = average heat of formation of the metalloids in the charge per unit volume of oxygen, VO2M = the volume of oxygen that reacts with the metalloids to convert the metalloids to their oxides.
where:
QO2M = heat released by the metalloids, AVHFM = average heat of formation of the metalloids in the charge per unit volume of oxygen, VO2M = the volume of oxygen that reacts with the metalloids to convert the metalloids to their oxides.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/540,125 US3955968A (en) | 1971-06-15 | 1975-01-10 | Method for determining the temperature of a molten metal bath |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1050786A true CA1050786A (en) | 1979-03-20 |
Family
ID=24154113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA239,186A Expired CA1050786A (en) | 1975-01-10 | 1975-11-07 | Method for determining the temperature of a molten metal bath |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1050786A (en) |
-
1975
- 1975-11-07 CA CA239,186A patent/CA1050786A/en not_active Expired
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