SU1357445A1 - Method of controlling combustion of fuel in continuous furnace - Google Patents

Abstract

The invention relates to the field of metallurgy and can be used when heating a metal in multi-zone firing furnaces. The aim of the invention is to improve fuel utilization, increase furnace productivity and reduce metal burnout by changing the oxidizer consumption ratio in areas where fuel consumption has changed over a period of time from the time the deviation of the oxygen content in the waste combustion products was eliminated until the next rejection. With an excess of oxygen in the waste combustion products, the consumption factor of the oxidizer is reduced in areas where fuel consumption has decreased, and with a shortage it increases in areas where fuel consumption has increased. With a common-mode change in fuel consumption in all zones, the consumption factor of the oxidizer is adjusted regardless of the sign of the change in fuel consumption. The correction signal is distributed over zones in proportion to the ratio of the change in fuel consumption in each zone to the total change in fuel consumption for the correction zones. The oxidizer consumption coefficient is increased when the air flow rate in the corrected zones reaches the maximum value in the zone with the minimum metal temperature and decreases when the air flow rate in the corrected zones is reached the minimum value in the zone with the maximum metal temperature. (L 00 pr | 4Sk 4 cl

Description

one

The invention relates to metallurgy and can be applied to heat

wa metal in multi-zone pass-through fiery furnaces.

The aim of the invention is to improve fuel use, reduce scale formation and increase furnace productivity.

This goal is achieved by adjusting the oxidizer consumption ratio in areas where fuel consumption has changed over a period of time from the moment of liquidation of a deviation in oxidizer content in waste fuel combustion products until the next deviation occurs, and when there is an excess of oxidant in the waste products. The oxidizer consumption factor is reduced in areas where fuel consumption has decreased, and with a shortage it is increased in areas where fuel consumption has increased. In the case of a common-mode change in fuel consumption (when switching to another type of fuel, for example, from gas to fuel oil and vice versa), in all zones the consumption factor of the oxidizer is adjusted regardless of the sign of the change in fuel consumption.

In quantitative terms, the correction signal; the signal is distributed over the furnace zones in proportion to the ratio of the change in fuel consumption per zone to the total change in consumption in the correction zone.

air flow rates). In the unheated zone; between the total smoke extraction and the first heated zone, a continuous selection of waste combustion products is carried out to determine their content 0 using an automatic gas analyzer.

The maximum possible fuel consumption in the zones is: Zone I 1250 nm; II zone 1250 III zone

15 1250 nm; Zone IV 500 nm; V zone of 500 nm.

With other things being equal, the minimum fuel consumption occurs when the oxygen content in the waste

„„ Products of combustion equal to 1.8%, and when the fuel consumption for every 100 nm changes, which causes a change in the oxygen content of the smoke, the oxidizer consumption ratio must be changed to 0.034 to eliminate the deviation C,

When operating the furnace with temperatures in zones I-V 1100; 1200; 1230; 1250 and 1250 С and given air consumption coefficients (с /) 1,2; 1.1; 1.05; 0.95 and 0.95 fuel consumption by zones is 800, 800; 700, 300; 250 nm. Og content 1.8%.

In the process of work in zones II-IV

thirty

40

zones that are set up. When the flow rate is reached, the air fuel consumption in the adjustable zones decreases by up to 600, 600 and 250 nm, respectively.

which causes an increase in the oxidizer in the waste products of combustion to 4.5%. The overall reduction in oxidizer consumption coefficient is 0.493. The correction signal according to the proposed method is distributed: on zone II 0.2-, on zone III 0.2j on zone IV, 0.093, i.e. set points in zones II 0.9; III 0.85; Iv 0.857. The oxygen content in the waste combustion products is reduced to

the maximum possible value of the oxidizer consumption coefficient is increased in the zone with the minimum temperature of the metal and reduced when reaching

air flow in adjustable zones is the minimum possible value in the zone with the maximum metal temperature.

The correction is made until the content of the oxidizing agent in the waste combustion products is not as specified.

Example 1. In an annular furnace, carbon steel blanks are heated from 20 to 1220-1260 ° C and then fed to the mill.

The furnace has one unheated and five independently heated zones and operates according to the counter-current principle. Numbers of heated zones are taken along with the movement of the metal. Each of them provides automatic temperature stabilization and ratio

45

50

1.95%, but does not reach the optimum value. The air flow rates in zones II-IV reach the minimum allowable values, therefore, an additional correction is carried out according to the proposed method in zone V (zone of issue), where the metal has a maximum temperature of 55, reducing C / 0.1. After that, the content of O in the combustion products reaches an optimum value of 1.8%.

13574452

the cost of fuel - air (by asking regulators to correspond

0

air flow rates). In the unheated zone; between the total smoke extraction and the first heated zone, a continuous selection of waste combustion products is carried out to determine their content 0 using an automatic gas analyzer.

The maximum possible fuel consumption in the zones is: Zone I 1250 nm; II zone 1250 III zone

5 1250 nm; Zone IV 500 nm; V zone of 500 nm.

With other things being equal, the minimum fuel consumption occurs when the oxygen content in the waste

“Combustion products equal to 1.8%, and when the fuel consumption for every 100 nm changes, which causes a change in the oxygen content of the smoke, the oxidizer consumption ratio must be changed to 0.034 to eliminate the deviation C,

When operating the furnace with temperatures in zones I-V 1100; 1200; 1230; 1250 and 1250 С and given air consumption coefficients (с /) 1,2; 1.1; 1.05; 0.95 and 0.95 fuel consumption by zones is 800, 800; 700, 300; 250 nm. Og content 1.8%.

In the process of work in zones II-IV

0

Claims (3)

1.95%, but does not reach the optimum value. Air flow rates in zones II-IV reach the minimum allowable values, therefore, additional correction is carried out according to the proposed method in zone V (zone of issue), where the metal has a maximum temperature, reducing C / 0.1. By this, the O content in the combustion products reaches an optimal value of 1.8%. After several hours of operation, the following economic parameters are obtained in this mode: total natural gas consumption 1400, furnace capacity 20.5 t / h, specific fuel consumption 68.3 nm / t; metal heating time 40 min; waste metal of 1.04% of the initial weight of the metal; metal temperature at issue 1240 C, After the removal of the economic indicators, the corrective signal is removed, the oxygen content in the waste combustion products is 4.5%. It is reduced in a known manner, entering successively a correction for a decrease in d in 1-V zones by the value: 0.15; 0.12; 0.1; 0.08 and 0.05. The oxygen content decreases to 2.3%, but does not reach the optimum. Therefore, the second correction cycle is carried out, reducing the c / in zone I by 0.15. After this, the content of 02 in the combustion products reaches an optimum value. After several hours of operation, the following economic indicators are obtained: total fuel consumption is 1400, furnace productivity is 19.7 t / h, specific fuel consumption is 71, metal heating time is 42 min, metal waste is 1.07% of the initial metal weight, metal discharge temperature is 1235 ° s Example 2. When operating the furnace with temperatures in zones I-V 1100; 1200; 1230, 1250 and 1250 ° С and given air consumption coefficients 1.2j 1.1; 1.05 j 0.95 and 0.95 fuel consumption by zones is 800, 800 700; 300 and 250 nm. The content of Oj in the waste products of combustion is 1.8%. During operation in the III-V zones, the fuel consumption increases, respectively, by 500, 200 and 250 nm, which causes a decrease in the 02 content in the combustion products to 1.25%. The total change in the oxidizer consumption coefficient is 0.323. The correction signal according to the proposed method is distributed: on zone III, 0.17; on zone IV 0.068; on V zone 0.085, i.e. actual setpoints for steel zones d III 0.88; d IV 0.882; about V 0,865. The oxygen content in the waste combustion products rises to 1.4%, but does not reach the optimum value. Air flow in III and IV zones reach their maximum value (12,500; 5,000-5,000 nm), therefore, according to the proposed method, additional correction is carried out in zone I (posad zone), where the metal has a minimum temperature, increasing o / by 0.2, which leads to P a rise of 0 in combustion products to an optimal value of 1.8%. After several hours of operation in this mode, the following economic indicators are obtained: the total consumption of natural gas is 3800, productivity g furnace 70 t / h; specific fuel consumption 54.3 nm / t; metal heating time 1 h 40 min, metal waste 1.04% of the initial weight, the temperature of the metal on issue. After the removal of economic indicators, the correction signal is removed, the content of Oj in the combustion products is 1.25%. It is increased in a known manner, sequentially entering a correction. 5 in zones I-V, increases from / by: 0.05; 0.08; 0.1; 0.12. After applying a correction signal to IVzone, Oj content is optimal 1.8%. After several hours of work Q get the following indicators: total natural gas consumption is 3800 nm / h - furnace capacity 67 t / h; specific fuel consumption 56.7; metal heating time 1 h 44 min; metal loss 1.07% of the initial weight; metal temperature on higher 1240 S. Example 3. When maintained in zones I-V, respectively, the temperature of 1100; 1200; 1230 and 1250 C and d 1.25i 1.2; 1.1; 0.9 and 0.9 content 0; is 0.5%, fuel consumption is reduced in all zones by 1.5 times (the furnace is heated with fuel oil). To eliminate the deviation 62 from the given value in IVsb, increase from / by 0.6; 0.6; 0.55; 0.45 and 0.4, respectively. After 0 reaches the optimal value of 1.8%, the total consumption of fuel oil 2730, metal heating time 2 and 10 min; furnace capacity 41 T / H-, metal waste -1.5%; specific fuel oil consumption 66.6 temperature metal on issue. After 3 hours of work, the temperature returns to the initial setpoints,. and d (respectively 1100; 1200; 1230; 1250 and 1250 ° C and 1.25-, 1.2; 1.1; 0.9-, 0.9 and 0.5%). 0 Raising 0. in j j. the combustion products are increased by zones according to a known method with decreasing steps of 0.2 0.2; 0.18; 0.15, 0.12. After the first cycle, the content of O. reaches 1.2%. Therefore, a second correction cycle is performed for the same values, the content is 0 1.6%. Only after the third cycle, the content of Oj reaches an optimal value of 1.8%. The total fuel oil consumption is 2890, the metal heating time is 2 and 18 min, the furnace productivity is 41 t / h, the metal waste is 1.52%, the specific fuel oil consumption is 70.5, the temperature of the metal at issue. Thus, in comparison with the limestone method of controlling the burning of JQ from the sign of the change in fuel consumption, fuel by means of a serial box 2. The POP.1 method, characterized in that the correction signal is distributed over zones in proportion to the proposed method, which allows for fuel consumption of fuel in the zone to total change by / h / 5% to reduce the waste metal by 1% and increase the furnace capacity by "3.5%. The reaction of the oxidizer consumption coefficient over the furnace zones with a successively decreasing step from zone to zone. fuel consumption for adjustable zones. 3. The method according to claim I, characterized in that the coefficient of consumption of the oxidizing agent increases when the air flow rate in the corrected zones reaches the maximum value in the zone with the minimum metal temperature and decreases when the formula of the invention is reached 1, A method of controlling the combustion of fuel in a continuous furnace by controlling the consumption of oxidant from a cor30 3. The method according to claim I, characterized in that the coefficient of consumption of the oxidizing agent increases when the air flow rate in the corrected zones reaches the maximum value in the zone with the minimum metal temperature and decreases when the ratios are reached its composition of the outgoing air passage in the adjustable zones of the combustible ducts, is different in that, in order to improve the minimum value in the zone with the maximum metal temperature. Editor N.Rogulich Order 5970/24 Compiled by G.Kolchenko Tehred I.Popovich Proofreader G. Reshetnik Circulation 550Subscribe VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 five fuel consumption, increasing furnace productivity and reducing carbon loss, the oxidizer consumption coefficient changes in areas where fuel consumption changes during the time period from the moment of elimination of the deviation in oxidizer content in waste combustion products until the next deviation occurs, and with an excess oxidizer in the waste combustible products, the oxidizer consumption rate is reduced in areas where fuel consumption has decreased, and with a shortage it increases in areas where fuel consumption has increased, Fuel-phase change in all zones oxidant flow ratio is corrected independently 2. Method POP.1, characterized in that the correction signal is distributed over the zones in proportion to the ratio of the change in fuel consumption in the zone to the total change fuel consumption for adjustable zones. 3. The method according to claim I, characterized in that the oxidizer consumption coefficient is increased when the air flow rate in the corrected zones is reached the maximum value in the zone with the minimum metal temperature and is reduced when the air flow rate in the corrected zones is reached air flow in adjustable zones the minimum value in the zone with the maximum metal temperature.