Study of the Tar Obtained in Blast-Furnace Smelting of Peat Fuel and Smelting Materials
Abstract Generated abstract
This study characterizes tar deposits formed during experimental blast-furnace smelting of peat based fuel-smelting materials with iron-ore concentrate. The deposits were ground, solvent-extracted, fractionally distilled, and analyzed for group composition, with light neutral oils and phenols examined by gas-liquid chromatography. The organic matter was almost completely soluble in common organic solvents, and the tar differed somewhat from semicoking tar of the same materials, especially in phenols, bases, and carboxylic acids. Distillation gave about 48% distillate fractions and 52% pitch, while the light fractions contained appreciable aromatic hydrocarbons and phenolic compounds, indicating potential value as chemical raw materials.
Full Text
STUDY OF TAR OBTAINED DURING BLAST-FURNACE SMELTING OF PEAT FUEL-SMELTING MATERIALS
K. K. STRAMKOVSKAYA, L. L. USENKO, L. A. PONOMAREVA
(Presented by the Scientific-Methodological Seminar of the Faculty of Chemical Technology)
For the metallurgical evaluation of fuel-smelting materials (FSM) made from peat from the Tagan deposit and iron-ore concentrate from the Abagur beneficiation plant, smelting was carried out in the experimental blast furnace of the Baikov Institute of the Academy of Sciences of the USSR [1]. This furnace was not equipped with apparatus for condensing and capturing liquid products. However, when the furnace was dismantled, tar was found in the form of solid deposits on the surface of the upper grate cover. The hardness of the deposits was due to the presence in them of a large quantity of slag distillation product, since the process was conducted with a blast containing 38–40% oxygen, and the temperature in the reaction zone of the furnace reached 2300°C.
The tar product breaks apart readily. For investigation it was ground until it passed through a sieve with 0.25 mm openings.
Analysis of this product showed that it contained 35.12% combustible matter and 64.88% ash.
The organic portion of the solid deposits was extracted in a Soxhlet apparatus with various solvents. The results, given in Table 1, showed that 97.4% of their combustible matter dissolved in carbon disulfide, benzene, and chloroform, and only 0.6% did not dissolve in these organic solvents.
Table 1
Yield of Soluble Substances
| Solvent | Yield, % on the initial product | Yield, % on the combustible mass of the product | Yield, % on the extract |
|---|---|---|---|
| Carbon disulfide | 26.50 | 75.60 | 77.60 |
| Benzene | 3.22 | 9.20 | 9.41 |
| Chloroform | 4.42 | 12.60 | 12.99 |
| Total | 34.14 | 97.4 | 100.00 |
In view of the complete solubility of the organic matter of the solid deposits, the sum of all the extracts was taken to be the tar obtained during blast-furnace smelting.
The fractional composition of this tar is presented in Table 2. For comparison, data are also given there for peat semicoking tar obtained under laboratory conditions from the same peat. This tar, as is clear from the table, is strongly pyrolyzed, since it contains almost one and a half times more fractions boiling below 200°C and twice the yield of pitch than peat semicoking tar.
Table 2
Fractional composition of tars
| Temperature limits, °C | Yield of fraction, %: tar from blast-furnace smelting on fuel-smelting materials | Yield of fraction, %: peat semicoking tar |
|---|---|---|
| Up to 170 | 3.24 | 5.30 |
| 170—200 | 21.90 | 11.20 |
| 200—230 | 4.63 | 12.10 |
| 230—270 | 2.89 | 26.70 |
| 270—300 | 2.80 | 8.60 |
| 300—330 | 7.07 | 11.80 |
| 330—360 | 5.14 | — |
| 360 (pitch) | 52.70 | 24.30 |
The group composition, determined for the individual extracts and then calculated for the entire tar, is given in Table 3.
In comparing the values obtained for this tar with the group composition of the semicoking tar from the same fuel-smelting materials, we note some difference in the content of phenols, pyridine bases, and carboxylic acids.
Table 3
Group composition of the tar
| Components | % content in the extract: petroleum ether | % content in the extract: benzene | % content in the extract: chloroform | Content, % based on tar: blast-furnace smelting of FSM | Content, % based on tar: semicoking of FSM |
|---|---|---|---|---|---|
| Bases | 2.56 | 0.06 | 0.10 | 2.77 | 2.10 |
| Acids | 2.56 | 0.04 | 0.33 | 2.98 | 1.10 |
| Phenols | 10.36 | 0.64 | 0.65 | 11.66 | 14.10 |
| Neutral oils (by difference) | 62.12 | 8.67 | 11.91 | 82.59 | 82.70 |
| Total | 77.60 | 9.41 | 12.99 | 100.00 | 100.00 |
The light fraction from the distillation of the tar and the phenols boiling up to 230°C were analyzed by gas-liquid chromatography on an KhL-4 chromatograph. Apiezons L and M, taken in a 1 : 1 ratio and deposited in an amount of 20% on an inert INZ-600 support (fraction 0.25—0.5), were used as the stationary phase. Helium served as the carrier gas, supplied at a rate of 200 l/min. The temperature in the column was maintained at 200°C. The results of the analysis, given in Tables 4 and 5, show—
represent a considerable value of these products as chemical raw materials. Neutral oils contain a large quantity of valuable aromatic compounds.
Table 4
Component composition of the neutral oils of the light tar fraction
| Name of components | Content, % of oils |
|---|---|
| Benzene | 1.3 |
| Octane | 1.3 |
| Toluene | 3.8 |
| Ethylbenzene | 2.6 |
| m- and p-Xylene | 4.2 |
| o-Xylene | 8.9 |
| n-Propylbenzene | 8.0 |
| Mesitylene | 3.1 |
| 1,2,3-Trimethylbenzene | 3.4 |
| Indene | 27.3 |
| Pseudocumene | 6.3 |
| Unidentified | 29.8 |
Table 5
Component composition of phenols boiling up to 230°C
| Name of components | Content, % |
|---|---|
| Phenol | 25.0 |
| o-Cresol | 12.2 |
| m- and p-Cresol | 15.1 |
| 2,4-Xylenol | 7.4 |
| 2,3-Xylenol | 16.3 |
| Unidentified | 24.0 |
Conclusions
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It has been shown that the tar from an experimental metal smelting on peat fuel-smelting materials differs somewhat in group composition from the semicoking tar of these materials.
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The yield of distillate fractions from this tar is 48%, and the yield of pitch is 52%.
-
Resources of aromatic hydrocarbons and phenols have been identified in the light fractions of this tar.
LITERATURE
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S. I. Smolyaninov, G. I. Krinitsin, V. S. Arkhipov, Study of peat-ore briquettes in a laboratory blast furnace. Present collection.
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K. K. Stramkovskaya, L. F. Ponomareva, L. F. Glukhova, Study of the semicoking tar of peat fuel-smelting materials. Present collection.