RU2036735C1 - Method of regulating fuel agent supply to blast furnace - Google Patents

Abstract

FIELD: black metallurgy. SUBSTANCE: blast furnace gas temperature is measured to estimate precise quantity of carbon substituted with fuel agent and saving of tentative coke. The furnace output, its output increase and coke saving are determined regarding fuel agent quantity. Depending on these proportions quantity of fuel agent is altered. Regulating action is effected with interval of 5-20 per cent of set fuel agent discharge in time interval of 10-60 minutes. EFFECT: enhanced efficiency. 2 cl, 1 tbl

Description

 The invention relates to ferrous metallurgy, in particular to the technology of smelting cast iron in blast furnaces.

 Known methods for controlling the supply of fuel additives in the form of reducing gas in a blast furnace, in accordance with which the amount of reducing gas is determined by the parameters of the combined blast. For example, at the Chelyabinsk Metallurgical Plant, the supply of natural gas is controlled in such a way that the ratio of its consumption to the oxygen consumption is maintained within 1.2-1.3 (see Report on scientific research work R&D 147636. Chelyabinsk Metallurgical Plant. 1975).

These methods are not effective enough, since they do not take into account the degree of use of reducing gas in the furnace, the amount of coke replaced by the fuel additive, and the productivity of the furnace. When supplying natural gas to the blast furnaces of the metallurgical plant them. Dzerzhinsky degree of hydrogen use varies from 0.2-0.5 fractions of a unit, causing a change in the coefficient of replacement of coke with natural gas from 0.6 to 1.05 kg / m ³ . At the same time, the productivity of the furnace also changes significantly. As a result, the efficiency of natural gas use, the thermal state of the furnace and the quality of cast iron fluctuate.

 The closest to the invention in technical essence and the achieved results is a method for controlling the supply of reducing gas to a blast furnace, in accordance with which the amount of reducing gas is maintained at an extreme level corresponding to the maximum savings of conventional coke, and the coke mass is adjusted by incrementing the amount of coke replaced with reducing carbon spikes.

 However, this method is also not effective enough, since when determining the saving of conventional coke, the change in furnace productivity from the use of a fuel additive is not taken into account.

 When changing the amount of fuel additive, there are cases when the productivity of the furnace increases or decreases, which affects the saving of conventional coke due to an increase in productivity.

 Changing the furnace productivity and saving equivalent fuel when searching for an extremum of the amount of fuel additive can occur in various combinations: when increasing or decreasing the equivalent fuel economy, productivity increases or decreases, changes in the opposite direction or remains constant.

 Accounting for changes in furnace productivity and its assessment in the process of developing a control action on the regulation of the amount of fuel additive is a significant difference of the proposed method.

> 0, а

≥ 0 то количество топливной добавки увеличивают на следующем шаге, если

<0, а

≅ 0 то количество топливной добавки на следующем шаге уеньшают, если

0, и

0 то считают, что расход топливной добавки находится на оптимальном уровне, в остальных случаях определяют суммарное приращение экономии условного кокса ΣΔЭ_к
ΣΔЭ_к= ΔЭ_к+E_к·ΔP_м и отношение суммарного приращения экономии условного кокса к и приращению топливной добавки и если

> 0 количество топливной добавки увеличивают на следующем шаге и если

< 0 то количество топливной добавки уменьшают, если

0 то считают, что расход топливной добавки находится на оптимальном уровне. Во всех случаях, если

< 0 то расход топливной добавки не увеличивают.This goal is achieved by the fact that in the known method, which includes monitoring the input parameters of the process, determining the amount of replaced carbon fuel additive and saving conventional coke, finding an extreme amount of fuel additive corresponding to the maximum saving of conventional coke, correcting the coke mass in the feed when changing the amount of replaced fuel additive carbon, determine the adjusted values of the amount replaced by the fuel additive carbon and saving conventional coke, determine the production furnace capacity and the ratio of the increment in productivity ΔP _m and the increment in coke saving ΔE _to the increment in the amount of fuel additive ΔV _td and, depending on the magnitude of these ratios, establish the direction of change in the amount of fuel additive and in increments of 5 20% of the set fuel additive consumption over a time interval of 10- 60 min carry out regulatory action, while if

> 0, and

≥ 0, then the amount of fuel additive is increased in the next step if

<0, and

≅ 0 then the amount of fuel additive in the next step is reduced if

0 and

0 then they believe that the fuel additive consumption is at an optimal level, in other cases, determine the total increment of saving of conventional coke ΣΔЭ _to
ΣΔE _k = ΔE _k + E _k · ΔP _m and the ratio of the total increment of the savings of conventional coke to and the increment of the fuel additive and if

> 0, the amount of fuel additive is increased in the next step and if

<0 then the amount of fuel additive is reduced if

0 then they believe that the fuel additive consumption is at an optimal level. In all cases, if

<0, then the fuel additive consumption is not increased.

 The time interval through which the regulatory effect on the change in the amount of fuel additive is carried out in 10-60 minutes is due to the time delay of information on the composition of blast furnace gas. If the length of the pulse path from the dust collector to the gas analyzers of the top gas is large and is made by pipes of oversized diameter, then the delay time for information on the composition of the top gas can be 30 minutes or more. In this case, it is advisable to produce control actions on the change in the fuel additive no more than once every 60 minutes.

 If the pulse path provides a minimum delay time of information about the composition of the top gas about 5 minutes, then control actions on the search for the extremum of the amount of fuel additive are issued every 10 minutes.

The steps of changing the amount of fuel additive when searching for its extremum within 5-20% of the set flow rate are determined by the volume of the blast furnace and the frequency of regulation. At a low regulation frequency (once per hour) for small blast furnaces (1386 m ³ and below), the steps are selected within 10 20% and for blast furnaces 5000 m ³ and more 7-10% When the regulation frequency is increased, for example, to once every 10 minutes, steps are selected within 5-10%
The method is as follows.

1. When a fuel additive is fed into a blast furnace, its quantity and chemical composition (μ, γ), the amount of blown air and oxygen, the humidity of the blast, the content of CO, CO ₂ and H ₂ in the top gas, the temperature of the top gas, blast temperature, and the amount are measured feeds of materials loaded into the furnace, carbon content in coke.

V_тд

V_тд, кг/ч
и экономию условного кокса
Э_к

V_тдE₁-V_oE₂, кг/ч где μ,γ- соответственно количество водорода и углерода, образующихся в горне доменной печи из единицы топливной добавки (м³/м³ или м³/кг);
η_H2,η_CO степень использования водорода и окиси углерода, доли единицы;
t_к температура колошникового газа, ^оС;
V_o количество технологического кислорода, м³/мин;
V_т.д. количество топливной добавки (м³/ч или кг/ч);
Е₁ коэффициент эквивалентности расхода топливной добавки расходу кокса, кг кокса/м³ добавки или кг кокса/кг добавки;
Е₂ коэффициент эквивалентности расхода кислорода расходу кокса, кг/м³;
С

;С_Н2;С_СО2; С_СО соответственно, теплоемкость водяного пара, водорода, диоксида и окоси углерода при температуре колошникового газа, кДж/м³ ˙град;
5250, 10802, 12648 тепловые эффекты образования СО, Н₂О, СО₂ из СО соответственно, кДж/м³;
1,8667 количество СО, образуемого из 1 кг углерода кокса, м³/кг;
q теплота горения топливной добавки в горне печи, кДж/м³ или кДж/кг.2. Using the averaged values of the measured parameters for a time t within 10-60 minutes calculate the amount of carbon coke E _s , which is replaced by a fuel additive
E _c

V _td

V _td , kg / h
and saving conditional coke
U _to

V _td E ₁ -V _o E ₂ , kg / h where μ, γ are respectively the amount of hydrogen and carbon generated in the furnace of a blast furnace from a unit of fuel additive (m ³ / m ³ or m ³ / kg);
η _H2 , η _CO degree of use of hydrogen and carbon monoxide, fractions of a unit;
t _{to the} temperature of the top gas, ^о С;
V _{o the} amount of process oxygen, m ³ / min;
V _etc. the amount of fuel additive (m ³ / h or kg / h);
E ₁ coefficient of equivalence of fuel additive consumption to coke consumption, kg of coke / m ³ additive or kg of coke / kg additive;
E ₂ coefficient of equivalence of oxygen consumption to coke consumption, kg / m ³ ;
FROM

; With _H2 ; With _CO2 ; With _СО, respectively, the heat capacity of water vapor, hydrogen, carbon dioxide and carbon dioxide at the temperature of blast furnace gas, kJ / m ³ ˙ deg;
5250, 10802, 12648 thermal effects of the formation of CO, H ₂ O, CO ₂ from CO, respectively, kJ / m ³ ;
1.8667 the amount of CO formed from 1 kg of carbon coke, m ³ / kg;
q the calorific value of the fuel additive in the furnace furnace, kJ / m ³ or kJ / kg.

If reducing gas is used as a fuel additive, then the q value is determined
q 1658 CH ₄ + 6050 С ₂ Н ₆ + 10115 С ₃ Н ₈ + + 13796 С ₄ Н ₁₀ + 18053 С ₅ Н ₁₂ - 12648 СО ₂ -10802 Н ₂ О, kJ / m ³ here СН ₄ , С ₂ Н ₆ , C ₃ H ₆ , etc. the content of the corresponding components of the reducing gas;
1658, 6050, etc. the calorific value (or decomposition) in the furnace of the corresponding components of the reducing gas.

If solid or liquid fuels are used as additives, then
q Q _n ^p 121000 N ^p 12140 S ^p 13400 W ^p 23605 C ^p , kJ / kg where C ^P , N ^P , W ^P , S ^P content in solid or liquid fuel, respectively, of carbon, hydrogen, moisture and sulfur, kg / kg of fuel;
236.5 thermal effect of the formation of CO ₂ and CO, kJ / kg of carbon.

121000 thermal effect of the formation of H ₂ O, kJ / kg of hydrogen;
13400 thermal effect of the formation of H ₂ O, kJ / kg of water;
12140 thermal effect of the formation of SO ₂ , kJ / kg, S;
E ₁ ; E _2, respectively, the coefficients of equivalence of fuel additive consumption and oxygen consumption. These coefficients are constant and are determined from the cost of units of this raw material.

0,54 кг кокса/м³ V_тд
E₂

0,3 кг кокса/м³ O₂
Определяют производительность доменной печи. Ее можно определить известным способом (см. Довгалюк В.П. Основные номограммы доменного процесса. Киев; Техника, 1985 56 с)
P 1,43

0,5(CO₂+ΔH₂)+0,5(CO+CO₂)-βN₂, кг/мин
где V_кд количество комбинированного дутья, м³/мин;
СО, СО, N₂ составляющие колошникового газа,
ΔН₂ количество Н₂О косвенного восстановления, м³/100 м³ сухого колошникового газа;
α объемное отношение комбинированного дутья к азоту в дутье, м³/м³;
β объемное отношение кислорода к азоту в комбинированном дутье;
Оr окисленность шихты, кг кислорода шихты/кг чугуна.E ₁

0.54 kg of coke / m ³ V _td
E ₂

0.3 kg of coke / m ³ O ₂
The blast furnace performance is determined. It can be determined in a known manner (see Dovgalyuk V.P. Basic nomograms of the domain process. Kiev; Technique, 1985 56 s)
P 1.43

0.5 (CO ₂ + ΔH ₂ ) +0.5 (CO + CO ₂ ) -βN ₂ , kg / min
where V _{cd the} number of combined blast, m ³ / min;
СО, СО, N ₂ components of blast furnace gas,
? H ₂ H ₂ O amount of indirect reduction, ^m3 / 100 m ³ of dry blast furnace gas;
α volume ratio of the combined blast to nitrogen in the blast, m ³ / m ³ ;
β volume ratio of oxygen to nitrogen in the combined blast;
Оr oxidation of the charge, kg of charge oxygen / kg of cast iron.

 3. In steps of time t, from 5 to 20% of the set fuel additive flow rate, its amount is changed to an extreme value corresponding to the maximum saving of conventional coke with irreducible furnace productivity.

 For this purpose, after each step of changing the amount of the fuel additive, increments are determined in comparison with the previous averaging period t.

;

а также рассчитывают
ΣΔЭ_к ΔЭ_к + Е₃ ˙ΔР_м ˙ 60, кг/ч
и

, кроме этого на каждом шаге производят контроль влияния изменения расхода дутья на изменение производительности доменной печи, то есть определяют

Е₃ коэффициент эквивалентности приращения производительности экономии кокса. Его значение можно определить по стоимости единицы кокса и условно-постоянных расходах на выплавляемый чугун.E _s E _s (t) E _s (t-1)
E _to E _to (t) E _to (t-1)
P _m P _m (t) P _m (t-1)
ΔV _td V _td (t) V _td (t-1) and relations

;

and also count
ΣΔE _to ΔE _to + E ₃ ˙ΔР _m ˙ 60, kg / h
and

, in addition, at each step, the influence of the change in the flow rate of the blast on the change in the productivity of the blast furnace is controlled, that is, they determine

E _{3 is} the equivalence coefficient of the increment of coke saving performance. Its value can be determined by the cost of a unit of coke and conditionally constant costs for smelted cast iron.

PRI me R implementation of the method. The calculation is given for the operating conditions of a blast furnace with a volume of 1754 m ³ (see table).

At the moment of switching on the blast furnace in the control mode, it worked with a flow rate of 3100 m ³ / min. td 1090 ^о С, natural gas consumption was 10400 m ³ / h, oxygen content in the blast was 23/5%, steam consumption was 1.5 t / h.

At the first step of the input parameters, V _pg , V _d .

> 0,

> 0 и

> 0
Исходя из совокупности этих расчетных значений выдается рекомендация на увеличение расхода природного газа на 500 м³.The calculated parameters were obtained as follows:

> 0,

> 0 and

> 0
Based on the totality of these calculated values, a recommendation is issued to increase the consumption of natural gas by 500 m ³ .

In the second step, with a natural gas flow rate of 11,000 m ³ / h and a slight increase in blast flow rate to 3180 m ³ / min.

> 0,

>, 0

> 0
В результате этого вновь выдается рекомендация на увеличение расхода природного газа на 500 м³.

> 0,

> 0

> 0
As a result of this, a recommendation is again issued to increase the consumption of natural gas by 500 m ³ .

At the third step, at a flow rate of V _{pg of} 11500 m ³ / h, an increase in H ₂ in blast furnace gas up to 7% is observed, and the degree of use of H _{2 is} up to 0.4, the saving of coke carbon due to the use of natural gas has increased to 8375 kg / h.

> 0,

< 0 и

> 0 в связи с этим производится расчет ΔЭ_кΣ
ΔЭ

= 119,

< 0 при этом

> 0 таким образом необходимо увеличение расхода природного газа. Выдается рекомендация на 500 м³.

> 0,

<0 and

> 0 in connection with this, ΔE _{kΣ is calculated}
ΔЭ

= 119,

<0 at the same time

> 0 therefore an increase in the consumption of natural gas is necessary. A recommendation of 500 m ^{3 is} issued.

In the fourth step, at a flow rate of V _{pg of} 12,000 m ³ / h, η _CO increased to 0.4 η _H2 to 0.41. The amount of carbon replaced by the fuel additive was 8871 kg / h, productivity decreased to 2568 kg of cast iron per min.

> 0,

< 0,

> 0
Несмотря на уменьшение производительности ΔЭ_кΣ, которое учитывает изменение производительности составляет 216 кг/ч, то есть эффект добавления природного газа положительный. Выдается рекомендация на увеличение расхода природного газа еще на 500 м³.

> 0,

<0,

> 0
Despite the decrease in productivity, ΔE _kΣ , which takes into account the change in productivity, is 216 kg / h, that is, the effect of adding natural gas is positive. A recommendation is issued to increase the consumption of natural gas by another 500 m ³ .

At the fifth step, with a natural gas flow rate of 12,500 m ³ / h, there was an increase in the utilization of hydrogen η _H2 to 0.44. Carbon savings increased to 9730 kg / h. At the same time, the productivity of the blast furnace decreased and ΔР became negative, therefore, we evaluate the efficiency, therefore, we evaluate the efficiency by ΔЭ _кΣ
ΔE _kΣ 585 kg / h, that is, the effect of using natural gas taking into account productivity even with its decrease is positive, the recommendation follows to increase the consumption of natural gas.

показывает, что эта величина отрицательна. Это означает, что рекомендация на увеличение расхода природного газа не выполняются.However, the analysis of the ratio

shows that this value is negative. This means that recommendations for increasing the consumption of natural gas are not being implemented.

< 0,

> 0 В данной ситуации выдается рекомендация на уменьшения расхода природного газа.At the sixth step, with a slight increase in coke savings, a decrease in productivity also occurred. ΔE _kΣ 125 kg / h, that is, the effect is positive. ΔР _m / ΔV _{d is} also greater than 0. Moreover,

<0,

> 0 In this situation, a recommendation is issued to reduce the consumption of natural gas.

In the next step, there was a decrease in the efficiency of natural gas use η _H2 = 0.91. Coke carbon savings decreased to 9030 kg / h. Productivity decreased ΔР _m 49 kg / min.

> 0,

> 0, однако

< 0 и таким образом рекомендация на увеличение расхода природного газа не выполняется.

> 0,

> 0, however

<0 and thus the recommendation to increase the consumption of natural gas is not implemented.

< 0,

< 0 и

< 0 выдается рекомендация на уменьшение расхода природного газа. На девятом шаге расход природного газа составляет 11500 м³/ч. Э_спонизилось до 8368 кг/ч. Отмечается увеличение производительности ΔР_м 20 кг/мин.At the eighth step, there was a decrease in the degree of use of hydrogen η _H2 = 0.40. Down _with E, E _to ,

<0,

<0 and

<0 a recommendation is made to reduce the consumption of natural gas. In the ninth step, the consumption of natural gas is 11500 m ³ / h. E _with decreased to 8368 kg / h. There is an increase in productivity ΔР _m 20 kg / min.

> 0,

< 0 поэтому оценку производим по ΔЭ_кΣ.

> 0,

<0, therefore, we estimate by ΔE _kΣ .

<0, однако

> 0 и

< 0 поэтому рекомендация на увеличение расхода природного газа не выполняется.ΔЭ

<0, however

> 0 and

<0 therefore, the recommendation to increase the consumption of natural gas is not implemented.

> 0,

> 0 и

< 0 поэтому рекомендация на увеличение также отменяется.In the tenth step

> 0,

> 0 and

<0 therefore, the recommendation for an increase is also canceled.

>0,

< 0 поэтому оценку производим по ΔЭ_кΣ

> 0,

> 0 таким образом выполняется рекомендация на увеличение расхода природного газа.At the eleventh step, the productivity increased ΔР _m > 0, and the saving of coke E _with decreased

> 0,

<0 therefore, we estimate by ΔE _kΣ

> 0,

> 0, therefore, the recommendation to increase the consumption of natural gas is fulfilled.

> 0,

> 0 выдается рекомендация на увеличение расхода природного газа

> 0 поэтому рекомендация выполняется.At the twelfth step, the degree of hydrogen use increased η _H2 = 0.43. Saving carbon coke amounted to 9285 kg / h. Productivity increased by 52 kg / min.

> 0,

> 0 recommendation for increased natural gas consumption

> 0 therefore the recommendation is being implemented.

> 0,

> 0 и

> 0 поэтому выполняется рекомендация на увеличение расхода природного газа.At the thirteenth step, coke savings amounted to 9645 kg / h, productivity increased by 10 kg / min

> 0,

> 0 and

> 0 therefore, the recommendation is implemented to increase the consumption of natural gas.

At the fourteenth step, the consumption of natural gas is 13,000 m ³ / h, coke savings reached 10,069 kg / h, and productivity increased by 130 kg / min.

> 0,

> 0 и

> 0 выполнена рекомендация на увеличение расхода природного газа
На пятнадцатом шаге при расходе природного газа 13500 м³/ч η_H2возросла до 0,46. Экономия углерода кокса равна 10804 кг/ч, однако производительность снизилась на 50 кг/мин.

> 0,

> 0 and

> 0 recommendation to increase the consumption of natural gas
At the fifteenth step, with a natural gas flow rate of 13,500 m ³ / h, η _H2 increased to 0.46. Saving carbon coke is equal to 10804 kg / h, but productivity decreased by 50 kg / min.

> 0,

< 0 поэтому оценку производим по ΔЭ_кΣ
ΔЭ_кΣ 454 кг/ч

> 0

> 0 таким образом выполняем рекомендацию на увеличение расхода природного газа.

> 0,

<0 therefore, we estimate by ΔE _kΣ
ΔE _kΣ 454 kg / h

> 0

> 0, so we follow the recommendation to increase the consumption of natural gas.

At the sixteenth step, with a natural gas flow rate of 14,000 m ³ / h, the utilization of η _H2 increased to 0.49, coke carbon savings reached 11810 kg / h, and productivity increased by 79 kg / min.

> 0

> 0 однако

< 0 таким образом рекомендация на увеличение расхода природного газа не выполняется.

> 0

> 0 however

<0 thus the recommendation to increase the consumption of natural gas is not implemented.

> 0,

> 0 однако в связи с тем, что

< 0 расход природного газа не изменяем.At the seventeenth step, with a natural gas flow rate of 141000 m ³ / h, the degree of its use reached 0.51, coke carbon savings amounted to 12095 kg / h, production amounted to 2653 kg / min

> 0,

> 0, however, due to the fact that

<0 the consumption of natural gas is not changeable.

 Thus, based on the above example, it is shown that the method makes it possible to optimize the consumption of natural gas.

As a result of regulatory influences by changing the flow rate of natural gas, taking into account changes in the productivity of the blast furnace, an increase in the flow rate of natural gas from 10,400 m ³ / h to 14,100 m ³ / h was achieved, while the performance of cast iron remained virtually unchanged. The utilization of η _H2 increased from 0.36 to 0.51 and the coke carbon savings from the initial 7094 kg / h reached 12095 kg / h.

Claims (2)

1. METHOD FOR REGULATING THE FUEL ADDITION SUPPLY TO THE DOMAIN FURNACE, including measuring the composition of top gas, air consumption, fuel additive and process oxygen, the humidity of the blast, determining the amount of carbon replaced by the fuel additive and saving conventional coke, finding the extreme amount of fuel additive corresponding to the maximum saving of conventional coke, correction of the mass of coke in the feed when changing the amount of carbon replaced by the fuel additive, characterized in that it is additionally determined elyayut performance furnace P _m and productivity increment ratio P _m to the increment of flow rate of air blast ΔV _d and the ratio of the increment performance ΔP _m and increments saving coke ΔE _to to the increment of amount of the fuel additive ΔV _etc. and depending on the value of this relationship is set the direction of change in the number of fuel additives and with a step of 5 to 20% of the set fuel additive flow rate through a time interval of 10 to 60 minutes, a regulatory action is taken, moreover, if

then the amount of fuel additive is increased in the next step, if

then the amount of fuel additive in the next step is reduced if

it is considered that the fuel consumption of the additive is at an optimum level, in other cases determined by the total increment of coke saving conditional ΣΔE _to the formula
ΣΔE _to = ΔE _to + E _to ΔP _m
and the ratio of the total increment of savings of conventional coke to the increment of the fuel additive and, if

then the amount of fuel additive is increased in the next step and, if

then the amount of fuel additive is reduced if

they consider that the fuel additive consumption is at an optimal level, and in all cases, if

then the fuel additive consumption does not increase. 2. The method according to claim 1, characterized in that the amount of replaced carbon fuel additive is determined by mathematical expression

where μ, γ, respectively, the amount of hydrogen and carbon generated in the furnace of the blast furnace from a unit fuel additive, m ³ / m ³ or m ³ / kg;

degree of use of hydrogen and carbon monoxide, fractions of a unit;
t _{to the} temperature of the top gas, ^o C;
V _{t. d the} amount of fuel additive, m ³ / min or kg / min;

accordingly, the heat capacity of water vapor, hydrogen, dioxide and carbon monoxide at the top gas temperature, kJ / m ³ · deg;
5250, 10802, 12648 thermal effects of the formation of CO, H ₂ O, CO ₂ from CO, respectively, kJ / m ³ ;
1.8667 the amount of CO formed from 1 kg of carbon coke, m ³ / kg;
q calorific value of the fuel additive in the mining furnace, kJ / m ³ or kJ / kg.

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