Study of Chemical Products of Blast Furnace Smelting
Abstract Generated abstract
This study examines the yields of chemical products formed during laboratory blast furnace smelting using peat fuel flux materials, with a charge containing 65 percent peat based material and 35 percent hard coal coke. The authors measured gas composition, tar, gas gasoline, unsaturated compounds, and dust under a lower upper furnace temperature regime than in earlier experiments. Increasing the share of peat was associated with higher hydrogen and methane contents in the furnace gas, while dust levels remained below typical industrial blast furnace values. Tar concentrations rose markedly as the upper furnace temperature decreased, reaching a yield comparable to peat gasification, and the process also produced appreciable amounts of gas gasoline and unsaturated compounds.
Full Text
STUDY OF CHEMICAL PRODUCTS OF BLAST-FURNACE SMELTING
(Communication II)
G. I. Kravtsova, K. K. Stramkovskaya, S. I. Smolyaninov,
V. S. Arkhipov
(Presented by the scientific-methodological seminar of the CTF)
In order to clarify the possibilities of using peat fuel-flux materials in the chemical-metallurgical process, a series of experiments is being carried out on a laboratory blast furnace, with a study of the degree of influence of various factors on the principal indicators of blast-furnace smelting.
The purpose of the present work is to determine the yields of chemical products during blast-furnace smelting on peat fuel-flux materials having a carbon-to-iron ratio of 1.82. During the smelting, the initial charge contained 65% by weight of fuel-flux materials and 35% hard-coal coke. Heated air was used as the blast. The bosh temperature was maintained within the range 345–296°C.
The conditions investigated differed from those described earlier [1] by a greater use of peat (65% FFM versus 30%) and by a lower temperature regime in the upper part of the blast furnace (average bosh temperature 313°C versus 448°C).
We determined the yields of tar, gas gasoline, unsaturated compounds, and also the dust content of the gas. Tar and dust were captured by cotton wool filling a V-shaped tube; the yield of gas gasoline and unsaturated hydrocarbons was determined in total in similar tubes, but filled with activated carbon of the BAU grade. The bulk of the tar and water vapors condensed in the condenser and were collected in receivers located under each bend of the condenser.
During the blast-furnace smelting process, the gas composition was determined by the method described in the preceding work [2]. The average gas composition is presented in Table 1. Comparing the data of Table 1 with the results of the preceding smelting [2], some differences in the composition of the gases should be noted. Thus, the hydrogen yield increases to 3.8%, and that of methane to 0.78%. Such a change in the gas composition is explained by an increase in the proportion of peat pyrolysis gas in the bosh zone (from 4 to 5%) due to the increase in fuel-flux materials in the initial charge.
The dust content of the gas in both experiments fluctuated within the range 4–17 g/nm³, which is considerably lower than the dust content of gas from industrial blast furnaces operating at normal pressure [3].
The content of chemical products in the gas from blast-furnace smelting on peat fuel-flux materials is given in Table 2. As can be seen from Table 2, the tar content during the smelting process significantly
Table 1
Average gas composition
| Type of fuel | CO | CO₂ | H₂ | CH₄ | N₂ | O₂ |
|---|---|---|---|---|---|---|
| Coke | 29.40 | 2.00 | — | — | 67.40 | 1.20 |
| Coke + TPM | 30.70 | 2.300 | 3.80 | 0.79 | 61.04 | 1.30 |
Table 2
Content of chemical products in the gas
| Type of fuel | Top temperature, °C | Tar content, g/nm³ | Gasoline + unsaturated compounds content, g/nm³ |
|---|---|---|---|
| Coke + TPM | 345 | 3.0 | — |
| » | 363 | 7.0 | 6.5 |
| » | 312 | 6.0 | 7.8 |
| » | 302 | 12.8 | 9.8 |
| » | 296 | 20.8 | 8.4 |
increased (from 3 to 20.8 g/nm³), while that of gas gasoline and unsaturated compounds remained approximately constant, but fairly high (7–9 g/nm³), throughout the entire experiment.
The increase in the tar content in the gas is explained by the decrease in temperature in the upper part of the blast furnace (from 345 to 296°C), where thermal decomposition of the peat takes place, and, apparently, the tar released does not undergo significant pyrolysis.
A tar content in the gas of 20.8 g/nm³ gives, calculated on the combustible mass of peat, a tar yield of 13.2%, which is of the same order as in the gasification of peat in gas producers [4].
The minimum tar yield in the process under study (5.1% on the combustible mass of peat) is nevertheless higher than in the gasification of highly metamorphosed brown and hard coals (up to 3% on the combustible mass) [5].
Conclusions
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The yield of chemical products has been determined for one of the modes of blast-furnace smelting on peat fuel–smelting materials.
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It has been shown that, when the blast-furnace process is carried out on the basis of peat fuel–smelting materials, considerable quantities of tar and gas gasoline are obtained.
Literature
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S. I. Smolyaninov, V. S. Arkhipov, G. G. Krinitsyn. Testing of peat fuel–smelting materials in a laboratory furnace. Izv. TPI (in press), vol. 214.
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K. K. Stramkovskaya, S. I. Smolyaninov, V. S. Arkhipov, G. I. Kravtsova. Study of the chemical products of blast-furnace smelting (communication 1). Izv. TPI (in press), vol. 214.
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Blast-Furnace Production (Handbook), vol. II, Metallurgizdat, Moscow, 1963.
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N. N. Bogdanov. Semicoking and Gasification of Peat. Gosenergoizdat, Moscow, 1947.
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M. V. Gofman. Applied Chemistry of Solid Fuel. Metallurgizdat, Moscow, 1963.