RU2002812C1 - Converter waste gas utilization method - Google Patents

Description

vital gas of the right amount with high properties is not needed. With excess natural gas, soot may form in the mixture.

When natural gas is supplied to the converter gas, the temperature drops from 1500-1700 ° С to 900-1000 ° С due to the chemical reaction between the converter gas CO2 and natural gas CH4. The resulting reducing gas with a temperature of 900-1000 ° C has higher reducing properties, its amount increases. Then it is passed through an iron ore charge, taken in the form of calcined pellets in an amount of 1.0-1.5 kg per 1 m3 of gas obtained.

The reduction of the calcined pellets in an amount of 1.0-1.5 kg per 1 m3 with a reducing gas with t 900-1000 ° C ensures the complete restoration of the calcined pellets, i.e. the most complete use is made of the chemical energy of the obtained gas.

When recovering calcined pellets in an amount of less than 1.0 kg per 1 m with reducing gas with a temperature of 900-1000 ° C, it leads to an excess of reducing gas and its underutilization, i.e. reduced by the use of its chemical energy. When recovering burnt pellets in an amount of more than 1.5 kg per 1 m with reducing gas with t of 900-1000 ° C, not all pellets are restored, some of them remain unrestored, therefore, an increase in the number of burnt pellets is more than 1.50 kg 1 m increases the energy consumption for blowing the layer, but does not increase the amount of reduced iron, which ultimately reduces the degree of utilization of the chemical energy of the converter gas. After reduction of the calcined pellets with the formed gas, raw pellets are fired from the iron ore charge using its chemical energy.

The hot calcined pellets are fed directly to the reduction, which contributes to a better reaction of the reduction of the calcined pellets and, accordingly, the most complete utilization of the chemical energy of the converter gas.

The drawing shows a flow chart of the implementation of the proposed method.

The technological scheme of the implementation of the proposed method includes a converter 1 connected to a flue 2 of exhaust gas gases 3. A flue 2 is connected to a natural gas pipeline 4. A cooled grate 6 is installed in the flue 2, on which annealed pellets 7 are located, and a cooled grate 8 on which is located a layer of raw pellets 9 of iron ore. Of

hopper 10 is fed raw pellets 9 from iron ore. The gas duct 2 is connected to a pipe 11 for air, located between the cooled grilles b and 8. The pipe 12 is designed to output

exhaust gas 13. Arrow 14 shows the direction of the gas formed after the reduction of the annealed pellets.

Converter gas 3 with a temperature of 1500-1700 ° C is discharged from converter 1 and sent to gas duct 2. Natural gas pipeline 4 is supplied to gas duct 2 and natural gas 5 is fed into exhaust gas 3 in an amount of 0.08-0 , 12 m3 / m3kg. Here a chemical reaction occurs between natural gas methane 5 and carbon dioxide converter gas 3

CO2 + CH4 2CO + 2H2

As a result of this operation, the temperature of the obtained gas will be 900-1000 ° C, its volume will increase by 8-10%, the CO content will increase to 95% and approximately 5% will be H. The resulting reducing gas is passed through a layer of calcined pellets 7, which located on the cooled grate 6. In this zone, the calcined pellets are restored 7. The following reactions occur:

ReO + CO Rech CO2

40

Fe203 + 3CO 2Fe + 3C02

FeO + H2 Fe + H20 Rv20z + ZN2 2Re + ZN20

The utilization of CO and H2 will be 40 and 15%, respectively.

The resulting gas 14 after the reduction of the calcined pellets 7 contains up to 58% CO and a temperature of 450-550 ° C. Then it enters the firing of the raw pellets 9, which are located on the cooled grate 8 and are fed from the hopper 10. For combustion of the exhaust gases after the restoration of the fired pellets 7, the air 14 is supplied 11. After firing the pellets 9, the exhaust gases 13 are sent to the nozzle 12 to gas cleaning (not shown in the drawing). Then, the calcined pellets 9 are directly fed for recovery by hot reduction. Natural gas supply 5 high temperature effluent stream

converter gases 3 allows cooling to be carried out without significant expense due to the use of chemical energy of the exhaust converter gases. In this case, a gas is used with a high CO content for the reduction and calcination of the iron ore charge (pellets 7 and 9, respectively).

Example 1. Converter gas 3 with a temperature of 1500 ° C was fed into a gas duct 2 with a diameter of 500 mm. Natural gas 5 was supplied to the duct 2 with a temperature of 25 ° C in an amount of 0.08 m3 / m3 kg. After mixing the gas flows 3 and 5, the temperature of the mixture was 900 ° C. To this stream was added 1.0 kg of calcined pellets 7 per 1 m3 of the resulting mixture. After reduction, pellets 7 were cooled by air. The utilization of the resulting mixture of gases 3 and 5 was 40%. Next, the exhaust gas 14 flowed upward through the gas duct 2, it was burnt in a stream of air supplied from the pipeline 11, and the exhaust pellets were fired by the exhaust gases 14. Next, the restored pellets 7 were discharged, and fired hot pellets 9 were fed to the grid 6. , the next batch of crude pellets from an iron ore charge was loaded onto grid 8.

As a result, at the end of the process, it was found that the use of the chemical energy of the converter gas was approximately 100%. The converter gas utilization rate was 90%.

EXAMPLE 2. The disposal method was carried out on the same equipment as in Example 1, while maintaining the operations and their sequence. But converter gas 3 with a temperature of 1600 ° C was supplied to the duct 2. It was mixed with natural gas 5 with a temperature of 25 ° C in an amount of 0.1. 1.3 kg of pellets per 1 m3 of gas were added to the resulting mixture at a temperature of 950 ° C. The utilization of the resulting mixture was 40%. Then, the And gas obtained as a result of the reduction of the calcined pellets was burned in a stream of air, and the combustion products were fed to the burning of the raw pellets 9, The calcined pellets without cooling were fed to the reduction. As a result, the chemical energy of the converter gas was fully utilized (100%). The total use of gas (i.e. its utilization) is 90%,

PRI me R 3. The method was carried out similarly to the method of example 1, but the Converter gas 3 with a temperature of 1700 ° C was mixed with natural 5 with a temperature of 25 ° C

in an amount of 0.12 m3 / m3kg. To the resulting mixture with a temperature of 1000 ° C was added 1.5 kg of calcined pellets 7 per 1 m3 of gas. Degree of use of reducing

the gas mixture was 40%. Next, the exhaust gas mixture was burned in a stream of air, and the combustion products were sent for calcining the pellets 9, and the calcined pellets in hot form were fed for reduction. As a result, 100% utilization of the chemical energy of converter gas was obtained, with a total utilization of converter gas (utilization) of 90%. PRI me R 4, the Method was carried out according to

Example 1, but converter gas 3 with a temperature of 1400 ° C was mixed with natural gas 5 in an amount of 0.6 m / m3 kg. 0.5 kg of calcined pellets 7 was added to the resulting gas reduction mixture. The degree of use of the reducing gas mixture was 33%. Exhaust gas 14 was burnt in a stream of air, and raw pellets 9 were burned with combustion products, hot calcined pellets were fed for reduction. The chemical energy of the converter gas was used at 94%, i.e. when the mode values go beyond the declared intervals, the efficiency of using chemical

energy decreased and the total use (utilization) of converter gas was 83%.

Example 5. The method is carried out as in example 1, but converter gas with a temperature of 1500 ° C was mixed with natural gas in an amount of 0.12 m3 / m kg. The quality of the mixture decreased due to the appearance of soot. In the resulting mixture with a temperature of 850 ° C supply 2 kg of pellets per 1 m of gas. Power

the use of the reducing mixture was 30%. Exhaust gas was used to pellet firing, and hot fired pellets were fed for reduction. The use of chemical energy of the gas amounted to 89%. The overall converter gas utilization efficiency is 78%, i.e. there has been a decrease in the utilization of chemical energy and the utilization of converter gas.

The proposed method improves the efficiency of using the chemical energy of the converter gas.

(56) Copyright certificate of the USSR No. 236495, cl. C 21 C 5/38, 1967.

USSR copyright certificate Mg 589259, cl. C 21 C 5/38. 1976.

USSR copyright certificate No. 631538, cl. C 21 C 5/38. 1975.

Claims (1)

The claims METHOD FOR DISPOSAL OF CONVERTER GASES, comprising supplying converter gas through a layer of iron ore 5 charge, characterized in that, in order to increase the efficiency of using chemical energy of converter gas, natural gas is fed into the exhaust converter gas at a temperature of 1500 - 1700 C at 10 the amount of 0.08 - 0.12 m3 / m3 kg. then, with the resulting gas mixture, the iron ore charge is reduced in the form of calcined pellets in an amount of 1.0-1.5 kg per 1 m of the obtained gas mixture, and the raw gas formed after the reduction of the calcined pellets is fired from the raw iron pellets, while the calcined pellets are fed for reduction hot. Yu G.