Investigation of Tar from Blast-Furnace Smelting Using Peat Fuel-Smelting Materials
Abstract Generated abstract
This study examines tar formed during laboratory blast-furnace smelting with peat fuel-smelting materials in a burden containing hard-coal coke. The tar, collected from condensation equipment and purified from mechanical impurities by solvent extraction, was characterized by fractional distillation, group composition analysis, and gas-liquid chromatography of isolated phenolic fractions from both tar and tar water. The results indicate that its fractional and group composition differs only slightly from peat semicoking tar, although the blast-furnace tar contains less phenols overall, apparently because some phenols dissolved in associated water. Its phenolic fraction is relatively heavy and contains higher proportions of monohydric phenol and cresols than reported for coal-coking tar.
Full Text
INVESTIGATION OF TAR FROM BLAST-FURNACE SMELTING ON PEAT FUEL-SMELTING MATERIALS
(Communication II)
G. I. Kravtsova, K. K. Stramkovskaya, S. I. Smolyaninov,
V. S. Arkhipov
(Presented by the scientific-methodological seminar of the KhTF)
Peat fuel-smelting materials (TFM), in which the ratio of carbon to iron was 0.502, were tested in a laboratory blast furnace [1]. During smelting, the initial burden contained 40% by weight fuel-smelting materials and 60% hard-coal coke. Heated air was used as the blast. The grate temperature was maintained at about 448°C.
During smelting, thermal decomposition of peat occurred in the upper part of the blast furnace. The products of peat pyrolysis—tar and water—were carried off by the gas and condensed in the condensation equipment of the installation. The collected tar was heavily contaminated with mechanical impurities carried by the gas from the blast furnace. For investigation, the tar was separated from contaminants by extraction with benzene and chloroform. The fractional composition of the pyrolysis tar, determined by distillation from a flask with a one-ball attachment, is given in Table 1.
Table 1
Fractional composition of tars
| No. | Temperature limits, °C | Yield of fractions, %: blast-furnace smelting tar | Yield of fractions, %: peat semicoking tar |
|---|---|---|---|
| 1 | Up to 170 | 9.1 | 5.3 |
| 2 | 170–200 | 8.6 | 11.2 |
| 3 | 200–230 | 31.6 | 12.1 |
| 4 | 230–270 | 9.1 | 26.7 |
| 5 | 270–300 | 7.4 | 8.6 |
| 6 | 300–330 | 8.1 | 11.8 |
| 7 | 330 | 24.7 | 24.3 |
| 8 | Losses | 1.6 | 0 |
Analyzing the results obtained and comparing them with data from the study of peat semicoking tar, we note their slight difference in fractional composition. Thus, 17.7% of fractions boiling up to 200°C were obtained from the blast-furnace smelting tar, and 16.5% from the semicoking tar. The total yield of fractions boiling up to 300°C from both tars is, respectively, 47.8–47.4%. The different yields of individual fractions are explained by the low sharpness of rectification.
The group composition of the tars from blast-furnace smelting and from semicoking is presented in Table 2. Comparing the corresponding indices, we see that these tars differ in their phenol content. The considerably smaller amount of phenols in the blast-furnace-smelting tar is apparently explained by the fact that some of them dissolved in the large volume of water with which the tar came into contact during its extraction from the condensation part of the installation.
Table 2
Group composition of tars
| No. | Components | Content, % of tar: blast-furnace smelting TFM | Content, % of tar: semicoking TFM |
|---|---|---|---|
| 1 | Bases | 2.0 | 2.1 |
| 2 | Acids | 1.2 | 1.1 |
| 3 | Phenols | 8.2 | 14.1 |
| 4 | Neutral oils (by difference) | 89.6 | 82.7 |
Crude phenols were isolated from the tar water and from the tar. They were then distilled into fractions at atmospheric pressure. Distillates from the initial boiling point to a temperature of 240°C were analyzed by gas-liquid chromatography on an KhL-4 chromatograph with a column 4 mm in diameter and 2.5 m long. Stabilized castor oil, deposited in an amount of 20% on INZ-600 (0.5–0.25% fraction), was used as the stationary phase. The experiments were carried out at a column temperature of 195°C and a carrier-gas (helium) flow rate of 130–140 ml/min. The results of the investigations are presented in Tables 3 and 4.
The main portion of the phenols isolated from the tar water (Table 3) consists of phenol (41.7%), cresols (15%), and higher phenols boiling above 240°C (31.0%).
The crude phenols of the blast-furnace-smelting tar (Table 4) are heavier. Their main components are phenols boiling above 240°C (41.7%), xylenols and ethylphenols (32.1%), and cresols (18.7%). Monohydric phenol in the crude phenols amounts to only 3.23%; however, its content in this tar is greater than in coal-coking tar (0.29% versus 0.26%). The presence of cresols in the blast-furnace-smelting tar is many times greater than their content in coke-oven tar (1.68% versus 0.46%) [2].
Conclusions
-
A tar from one of the regimes of blast-furnace smelting on peat fuel-smelting materials has been investigated.
-
It has been shown that, in group and fractional composition, this tar differs little from peat semicoking tar.
-
The blast-furnace-smelting tar contains a larger amount of monohydric phenol and cresols than coal-coking tar.
Table 3
Component composition of phenols isolated from tar liquor
| Components | Content by fractions, %, withdrawal temperature, °C: 100–170 | Content by fractions, %, withdrawal temperature, °C: 170–200 | Content by fractions, %, withdrawal temperature, °C: 200–220 | Content by fractions, %, withdrawal temperature, °C: 220–230 | Content by fractions, %, withdrawal temperature, °C: 230–240 | Content in crude phenols, %, withdrawal temperature, °C: 100–170 | Content in crude phenols, %, withdrawal temperature, °C: 170–200 | Content in crude phenols, %, withdrawal temperature, °C: 200–220 | Content in crude phenols, %, withdrawal temperature, °C: 220–230 | Content in crude phenols, %, withdrawal temperature, °C: 230–240 | Content in crude phenols, % |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Phenol | 71.00 | 65.60 | 51.70 | 63.50 | 47.50 | 19.40 | 13.70 | 9.75 | 6.43 | 2.52 | 41.71 |
| o-Cresol | 5.87 | 5.66 | 4.89 | 3.07 | 2.66 | 0.81 | 1.18 | 0.93 | 0.31 | 0.14 | 3.36 |
| 2,6-Xylenol | 15.77 | 11.09 | 20.63 | 15.45 | 30.60 | 2.28 | 2.32 | 3.84 | 1.56 | 1.62 | 11.62 |
| m-Cresol, p-cresol | — | 1.59 | 2.77 | 3.63 | 2.43 | — | 0.33 | 0.52 | 0.30 | 0.29 | 1.46 |
| 2,5-Xylenol; 2,4-xylenol; 3,5-xylenol; 2,3-xylenol | — | 3.60 | 3.90 | 7.34 | 8.59 | — | 0.76 | 0.73 | 0.75 | 0.30 | 2.69 |
| m-, p-Ethylphenols | — | 12.46 | 16.71 | 7.42 | 8.28 | 1.22 | 2.60 | 3.17 | 0.85 | 0.43 | 8.16 |
| Unidentified portion | — | — | — | — | — | — | — | — | — | — | 31.00 |
| Phenols 240 | — | — | — | — | — | — | — | — | — | — | — |
| Total | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 13.80 | 20.90 | 18.93 | 10.10 | 5.3 | 100.00 |
Table 4
Component composition of phenols isolated from tar of blast-furnace smelting
| Components | Content in the fraction, %, fraction withdrawal temperature, °C: up to 210 | Content in the fraction, %, fraction withdrawal temperature, °C: 210–240 | Content in crude phenols, %, fraction withdrawal temperature, °C: up to 210 | Content in crude phenols, %, fraction withdrawal temperature, °C: 210–240 | Content, %, in crude phenols | Content, %, in tar |
|---|---|---|---|---|---|---|
| Phenol | 7.37 | 2.60 | 2.64 | 0.58 | 3.83 | 0.29 |
| o-Cresol | 9.97 | 5.40 | 3.57 | 1.22 | 4.79 | 0.43 |
| m, p-Cresols | 26.18 | 20.04 | 9.37 | 4.58 | 13.89 | 1.25 |
| 2,4—2,5 Xylenols | 19.40 | 20.02 | 6.95 | 4.55 | 11.50 | 1.03 |
| 2,3—3,5 Xylenols; m, p-ethylphenols | 29.20 | 45.10 | 10.45 | 10.15 | 20.60 | 1.85 |
| Unidentified portion | 7.88 | 6.85 | 2.84 | 1.55 | 4.29 | 0.39 |
| Phenols 240 | — | — | — | — | 41.70 | 3.73 |
| Total: | 100.00 | 100.00 | 35.80 | 22.50 | 100.00 | 8.97 |
LITERATURE
-
S. I. Smol’yaninov, V. S. Arkhipov, G. G. Krinitsyn. Testing of peat fuel-smelting materials in a laboratory blast furnace. Izv. TPI (in press), vol. 214.
-
M. M. Dmitriev, Ya. M. Obukhovskii. A Concise Handbook of Coke Chemistry. Metallurgizdat, Moscow, 1960.