EXPERIENCE IN SEMI-COKING BROWN COAL FROM THE YARSKOYE DEPOSIT IN TOMSK OBLAST

I. V. GEBLER and V. F. STRAMKOVSKY

The USSR possesses enormous resources of brown coal. As early as 1937, according to geological survey data, these reserves were estimated at about 200,000 million tons.

Brown-coal deposits, being distributed more or less evenly over the territory of the USSR, can significantly improve the fuel supply of the national economy, which is especially important for regions remote from hard-coal basins. The development of local fuel bases through the exploitation of brown-coal deposits will make it possible to create the most rational and most economical fuel-supply system for all regions of the country [1,2,3].

The path to the most rational use of brown coal depends on its reserves and quality. When brown coal possesses certain properties, its comprehensive, energy-chemical use appears very advantageous, i.e., its use as raw material for obtaining a series of chemical products, such as gasoline, fuel oils, paraffin, phenols, wax, gas, etc., while the resulting semi-coke is used as an energy fuel in pulverized form.

The city of Tomsk is in extremely acute need of local fuel. At present Tomsk is still compelled to supply its power economy with coal brought in from Kuzbass, although it has the possibility of creating its own fuel base by developing and using local peats and brown coals.

In the vicinity of the city there are many brown-coal deposits, but published data on their reserves are still lacking. The presence of seams has been established only by discovered outcrops of strata at the surface in various places in Tomsk Oblast (the villages of Yar, Kazanka, Rezhetsa, Protopopovo, and others).

In 1939 the Tomsk municipal fuel department began developing a brown-coal deposit located 48 km from the city of Tomsk, upstream along the Tom River, near the village of Yar, but these works were subsequently abandoned. Further development of these workings and consumption of the coal depend to a considerable degree on investigating its quality and, through these investigations, establishing methods for its rational application.

The fuel properties of this brown coal, in terms of the possibility of using it in untreated form, were studied in the laboratory of steam boilers of the Tomsk Industrial Institute by Prof. Fuks, as a result of which it proved possible in ordinary furnaces to burn brown coal mixed with Kuzbass coals in certain proportions.

Another route for the energy use of this coal consists in preliminary briquetting. Laboratory experiments showed that even at a pressure of 500–700 kg/cm² a very strong briquette can be obtained. It is probable that the path of rational application and use in ca-

as a domestic fuel, brown coals of Tomsk Oblast lies in briquetting.

The development of mining operations would be considerably promoted by the possibility of using the coal as a chemical raw material for obtaining products needed by Tomsk and Tomsk Oblast no less than fuel, for example gasoline, kerosene, lubricating oils, paraffin, wax, phenols, etc.

The first results of investigations of coal from the Yarskoye deposit [8] gave grounds to assume that they possess valuable qualities as a chemical raw material. A large yield of primary tar was found, reaching up to 20% on the dry mass, and a yield of bitumen, upon extraction with alcohol-benzene, of up to 13%.

Coals from the Yarskoye and Kazanskoye deposits were subjected to investigation; there is no substantial difference between their properties and qualities. All the samples investigated contained, in the freshly mined state, about 50% water and about 25–30% ash on dry coal. The calorific value of the coal, by bomb calorimeter, was about 4600 kcal/kg on dry coal, and about 6400 kcal/kg on combustible mass.

The present work was undertaken for the purpose of investigating the quality of the coal from the standpoint of the yields of semi-coking products and the characteristics of these products, which makes it possible to obtain some basis for judgments about the value of the coal as a chemical raw material. The choice, for such a more or less detailed examination, of Yarskoye coal was due to the existence of workings at this deposit with two adits, driven for a length of 85 meters from the surface along the strike of the seam. Investigations of samples taken at various places of the seam also make it possible to judge the constancy of the coal quality across the deposit. In addition, Yarskoye coal will have primary importance in terms of ease of mining and connection with the city of Tomsk by the Tom River.

Eight coal samples were investigated; of these, 7 samples represented freshly mined coal taken from various places of the seam along its strike.

The samples were taken in compliance with all the necessary rules and were delivered to the laboratory on the day after sampling. All analyses and tests of yields were carried out as quickly as possible, in order to avoid the influence of oxidation, and were completed for all samples within 15 days.

In addition, oxidized coal from the same deposit was investigated, having lain in the open air for 1.5 years. This coal is designated as oxidized. The passports of the coal samples are given in Table 1.

Table 1

The delivered coal was a mixture of woody inclusions with an earthy mass, with the latter clearly predominating. By manual sorting, the earthy mass was separated from each sample. The results are given in Table 2. The separated components were then mixed again, and a proximate analysis was made for each sample by the usual methods.

Table 2

The results of the proximate analysis of all coal samples are presented in Table 3.

Table 3

The characterization of Yarskoye coals by proximate analysis distinguishes them little from brown coals of other deposits in the USSR [1, 2, 3]; their ash content is considerably lower than that of some Moscow Basin, Ukrainian, Ural, and other coals. A moisture content in the working fuel of about 50% is also usual for almost all brown coals. Such a high content of ash and moisture is undoubtedly an unfavorable quality of the Yarskoye brown coals, but it does not prevent their use. Their drying proceeds quite easily, as shown by Table 4 and Fig. 1, constructed

Table 4

on the basis of observations of the process of moisture removal under laboratory conditions (20°C) from a layer of coal 2 cm thick, spread on iron trays. The greater part of the external moisture was removed after 9 days, and after 18 days an air-dry state, under laboratory conditions, was observed.

Fig. 1

The process of drying brown coal before use is complicated by its cracking, and the presence of a large quantity of dust does not permit the use of the most widespread drying drums. However, chamber dryers [4] may prove quite suitable; and if the coal is used in finely crushed form, pneumatic drying may also be successfully applied.

All the above-mentioned coal samples, after drying under laboratory conditions to a moisture content of approximately 20%, were crushed and subjected to laboratory semi-coking by the Fischer method in order to determine the yields of products. Samples of weathered oxidized coal were also subjected to semi-coking.

For the investigation, the usual apparatus scheme was adopted, with an aluminum retort of 20 grams coal capacity, heated by a gas burner. To improve the uniformity of heating, during the experiment the retort was covered with an asbestos-lined hood. The heating rate in all experiments was the same and was expressed as follows:

During the first 25 minutes the temperature was raised to 200°; during the next 30 minutes to 300°; during the next 30 minutes to 400°; during the next 30 minutes to 500°; over the next 30 minutes the temperature was maintained at 520°.

Thus, each experiment lasted 2 hours 25 minutes, and the final temperature did not exceed 520°.

The receiver for the tar and condensed water was a Wurtz flask with a shortened neck, of 100 cm³ capacity, placed in a cooling bath at a temperature of +7, +8°C. The yield of tar was determined by direct weighing of the receiver, subtracting the amount of water distilled off with the xylol.

The gas yield was determined from the quantity of sodium chloride solution displaced from the gas-collecting vessel, saturated with the gas under investigation, with corrections for the change in temperature of the retort and the tar receiver, for the change in gas pressure in the gas holder after equalization of its ...

temperature, with the surrounding medium, and on the content of water vapor in the gas above a saturated solution of table salt.

The yield of semi-coke was determined by direct weighing after cooling of the hermetically sealed retort.

The course of the semi-coking process for three samples of oxidized coal, in terms of the rise in temperature and the change in gas evolution, is shown graphically in

Fig. 2

Figures 2, 3, and 4, from which it may be concluded that gas evolution begins at a temperature of about 250–300° and proceeds intensively in the

Fig. 3

interval 350–500°. By the end of the second hour, the process of gas evolution is almost complete.

During the semi-coking of all coal samples, the first drop of tar corresponded to a retort temperature of about 350–355°, after approximately

60 minutes from the start of the run. Vigorous tar formation occurred in the interval 380–420°.

The resulting primary gas was characterized by determining

Fig. 4

the specific gravity by Schilling, with correction for the admixture of air from the analysis by Hempel.^1)

The results of semi-coking of all samples are presented in Table 5. The data of this table indicate a fairly large yield of primary tar, fluctuating among samples of fresh coal around 17% and among samples of oxidized weathered coal around 12%. Moreover, the results for all samples show similarity, which indicates the consistency of the coal quality over the investigated part of the seam.

Table 5

Such high yields of primary tar make it possible to classify Yarsk brown coal as high-quality and, on this basis, to assume the advisability of industrial semi-coking.

^1) The correction for the admixture of air was made on the basis of the oxygen content in the gas, which is not formed in the process of semi-coking.

Compared with brown coals from other deposits of the USSR, the Yarskoye coals in many cases prove to be of higher quality. Most of our brown coals give a small yield of primary tar, reaching only 6–7% of dry coal.

Thus, for example, laboratory semi-coking in a Fischer retort of Chelyabinsk coal, with a moisture content of 16.89 and an ash content of 8.8%, gives a primary-tar yield of 5.5% [1]; coals from the Moscow region give an even smaller primary-tar yield, reaching only 3.3–5.2% [6].

Exceptions among the others in this respect are the Moscow-region bogheads, which give up to 44% tar [5], and some Ukrainian brown coals, which give on average up to 11–15% [10] primary tar on an anhydrous coal basis. The best in this respect are the Aleksandriya coals and the Yurkovskiye (Zvenigorodskiye) coals.

Consequently, the brown coals of the Yarskoye deposit, in their quality as a raw material for semi-coking, approach the Ukrainian brown coals of the Aleksandriya deposit, surpassing the latter in primary-tar yield.

The yield of semicoke is about 60–62% on dry coal for freshly mined coal and about 68–69—on weathered, oxidized coal. This increase in semicoke yield is consistent with the decrease in the yield of tar and gas.

The semicoke obtained is a black, completely non-caked powder¹ with an ash content \(A^c\):

The yield of volatiles from the average semicoke sample is 5.44% on an air-dry mass, with a laboratory moisture content equal to 1.60%.

The semicoke possesses a high adsorption capacity and hygroscopicity. In order to characterize the semicoke in this respect, observations were made of the change in its weight immediately after its production and cooling in a closed retort. The results are given in Table 6, and the general pattern of the change in the weight of the semicoke is shown, on the basis of this table, by the curve in Fig. 5; from these it is seen that adsorption and absorption of moisture occur most intensively during the first two days.

Table 6

Thereafter the rate of increase in weight continuously decreases and, with an increase in weight of 4.99% (on the 34th day), almost dies out. Experiments

¹ In the semi-coking of granular coal, the semicoke is obtained in granular form with low lump strength.

briquetting of this semicoke did not make it possible to obtain even a somewhat coherent lump.

A practical means of using the semicoke obtained may be its combustion or gasification in the pulverized state.

The calorific value of the semicoke is, evidently, somewhat greater than that of the coal itself, owing to the increased carbon content in the combustible mass; therefore its use for energy purposes is no less rational than that of the coal itself.

The third product obtained in semicoking is primary gas. As can be seen from Table 5, the yield of this product amounts to from 11.56 to 14.90% on dry coal and from 15.5% to 20.67% on the ash-free dry substance of the coal, which corresponds to yields of 94.1—105.0 m³/t for fresh coal and 88.2—87.1 m³/t for weathered, oxidized coal.

From Table 5 it is seen that, with approximately identical gas yields on the ash-free dry substance, fresh and oxidized coal give the latter a volumetric gas yield 10—15% lower, which is explained by the corresponding difference in specific gravities due to the higher content of CO₂ in the gas from oxidized coal. The gas obtained from oxidized coal has a specific gravity from 1.422 to 1.460, whereas gas from fresh coal has a specific gravity from 1.410 to 1.415 and only sample 2—1.430.

Fig. 5

The composition of the primary gas was determined by Tempeľ analysis for samples 8(a), 8(b), 8(v), and 7, i.e., for three samples of oxidized coal and one sample of fresh coal.¹)

The results of the analysis, after corrections for the amount of admixed air, which was determined on the basis of the oxygen contained in the mixture under study, are presented in Table 7.

Table 7

Such a large amount of CO₂ + H₂S does not make it possible to regard the resulting raw primary gas as a sufficiently perfect gaseous—

¹) For the remaining samples, the gas was examined only for CO₂, CnHm, and O₂, in order to be able to introduce corrections for specific gravity and gas yield, since from the amount of oxygen in the gas one can judge the volume of air mixed with the gas.

fuel; however, cleaning it of these components would significantly increase its value from an energy standpoint. Table 8 gives the results of recalculating the composition of the raw gas to the composition after cleaning to a content of \(\mathrm{CO_2 + H_2S}\) of 5% and to complete cleaning of the gas from these components. On the basis of the data obtained, Table 9 gives the calculated lower heating values of the raw and cleaned gases, as well as their yields. In this calculation the heating value of \(\mathrm{H_2S}\) was not taken into account.

Table 8

Table 9

Thus, as is evident from Tables 8 and 9, cleaning the gas of \(\mathrm{CO_2}\) and \(\mathrm{H_2S}\), even only to a 5% content of the latter, increases the heating value by approximately a factor of 2; and the gas thereby obtained, possessing a heating value of 5500–6000 \(\mathrm{kcal/m^3}\), will already, undoubtedly, be a very rich gas suitable for the most critical production purposes. The figures in Table 9, moreover, indicate the relatively better quality (in all three cases) of the gas obtained from fresh

coal, the calorific value of which after purification is approximately 500 calories higher. However, such purification reduces the gas yield by approximately a factor of 2, which will make it more expensive, requiring the seeking of a more rational method of purification.

In the process of semi-coking, the primary gas formed does not have constancy of composition over the time of distillation (depending on the temperature). The first portions of the gas evolved contain a larger amount of CO₂ than the subsequent ones; therefore, when fractionated gas withdrawal is used, it is possible at first to obtain a gas with a high CO₂ content in comparison with the average composition given in Table 7. In order to establish this possibility, during the semi-coking of weathered, oxidized coal, under the same conditions as in the other experiments, gas was withdrawn in three temperature intervals of the process:

Analogous corrections to those used previously were made for the gas yield, and the composition of the gas was determined (without combustion).

The results are expressed in Table 10.

Table 10

The data of this table indicate a significant superiority in quality of the last portions of gas. Obviously, the gas obtained in the III period possesses the qualities of a good fuel gas and is quite suitable for heating purposes. The yield of such gas with a CO₂ + H₂S content of 25.8% amounts to 37.3% of the total quantity; moreover, with fresh coal this percentage can probably be increased.

The gas of the I period, constituting 27.9% of the total yield, contains CO₂ + H₂S in an amount of 72.5%. This gas can quite well be used for technological purposes in the process of primary decomposition of phenolates, which will be obtained when washing fractions of primary tar in order to extract phenols from them.

The use of the carbon dioxide of this fraction for the decomposition of phenolates will at the same time serve as a method of gas purification, a method of increasing its calorific value, as a result of which the residue may be admixed with the III fraction and together with it directed to energy use. At the same time, the possibility is not excluded of withdrawing the gas in two periods, or of other methods of fractional gas withdrawal, with the aim of eliminating or reducing the yield of the intermediate II fraction, which in the present case, making up 34.8% of the yield, gives a CO₂ + H₂S content of 43.5%. Such a scheme for using the primary gas would probably make it possible to obtain, as a by-product, a gas with a calorific value in any case not less than 4000 kcal/m³, i.e., quite suitable for energy—

for energy purposes not only within the semi-coking plant itself but also outside it. In addition, the primary gas contains a fairly large content of hydrocarbons, the utilization of which is of no small interest. Among them there are hydrocarbons of both saturated and unsaturated character, and the latter may serve as raw material for the production of various monohydric and polyhydric alcohols.

The yield and composition of the primary gas obtained from Yarskoye brown coal differ little from the results of semi-coking other brown coals.

Central German brown coals give [7] a gas yield of up to 140 m³/t with a calorific value of 2000–3600 kcal/m³.

According to Solodovnikov [9] and Goffmann [6], coals from the Moscow Basin, when semi-coked, give from 40 to 60 m³/t with a calorific value of 4000–5000 kcal/m³. Chelyabinsk and Ukrainian coals likewise do not exceed the yield and quality of the gas obtained from Yarskoye coal [10].

The tar water obtained during semi-coking is not of primary practical interest. Its yield depends on the moisture content of the coal and on the conditions of the process, in which some amount of pyrogenetic water is also formed. The amount of the latter under the conditions of the experiments carried out from Yarskoye brown coal is obtained at up to 9.38% on the dry substance of the coal (Table 5). Moreover, as is evident from the table, the yield of pyrogenetic water for oxidized weathered coal in all cases [samples 8 (a), 8 (b), 8 (c)] is less than from freshly mined coal. Such yields of pyrogenetic water are typical for brown coals. This product contains various dissolved acids (mainly acetic acid) and phenols, as a result of which it gives an acid reaction. With a sufficiently large amount of tar water, it could serve as a source for obtaining crude phenols and acetic acid. Since all the coal samples represented a mixture of woody parts with earthy mass, it was of interest to compare the yields of semi-coking products from these components of run-of-mine coal. For this purpose, the residue of coal sample 3 was separated into the woody part and earthy mass, which were subjected to semi-coking in a Fischer retort under the same conditions as were used in the principal experiments.

The results of the proximate analysis and the product yields are presented in Table 11.

Table 11

It is evident from the table that both the proximate analysis and the product yields during semi-coking distinguish the earthy mass considerably from the woody part; moreover, the earthy mass gives a greater yield of tar and semi-coke with a smaller yield of pyrogenetic water. The gas yield is approximately the same. It is clear that, from the point of view of chemical processing, it is precisely the earthy mass that is of value, both in the sense of a higher tar yield and in the sense of the high quality of the tar and primary gas. At the same time, Table 2 indicates a clear predominance of the earthy mass in all the coal samples investigated.

To characterize the primary tar obtained during semi-coking, it was necessary to have about 1 kg of it. For this purpose, several semi-coking experiments were carried out in an iron retort with a capacity of 4 kg of coal.

The 1st sample of freshly mined coal and the weathered coal of the 8th sample were subjected to semi-coking. In both cases approximately 1 kg of primary tar was obtained.

The heating of the coal is characterized by the following schedule of temperature rise in the retort:

During the following 3–4 hours a temperature of 450° was maintained in the retort. The entire experiment lasted 8–9 hours. Before charging the retort, large pieces of coal were crushed to a size of not more than 5–6 mm. The yields of products in these experiments are given in Table 12. The recalculation to dry coal was made approximately on the basis of the yield of pyrogenetic water during semi-coking by the Fischer method (Table 5).

Table 12

As can be seen from the table, the tar yield from fresh coal differs little from the results of semi-coking in the Fischer retort (Table 5); however, the semi-coke yield is somewhat higher, and the gas yield lower, which is explained by the lower final temperature of semi-coking and by other differences in the process.

For the oxidized coal this difference in yields (somewhat greater) is explained by considerable losses of tar in the cooler; the semi-coking of the oxidized coal was carried out at the beginning and, possibly, with a somewhat higher ash content of the coal, since its residues were used.

These discrepancies, however, are of no substantial importance, since the purpose of the experiments was to obtain primary tar in an amount sufficient for carrying out its analysis, while drawing up the balance gives only a general characterization of the semi-coking process in the retort for comparison with the Fischer process.

The primary tar and tar water were collected in a receiver cooled with ice water and, after settling, separated. For better stratification, heating was carried out in a water bath at a temperature of 50° for three hours. The primary tar obtained at room temperature was a solidified dark-brown mass with a sharp odor.

The primary tar, dehydrated by settling, was subjected to analysis, in which the following were determined: retained moisture (by distillation with xylene), specific gravity at 50°C, solidification temperature, content of free carbon, carboxylic acids, bases, phenols, and neutral substances. The results of the analysis for both tar samples are given in Table 13.

Table 13

From the table it is evident that the primary tar of the Yarsk brown coals has a number of very valuable qualities, among which first of all should be noted its relatively low specific gravity, 0.916–0.927, which also explains its property of readily settling away from water down to a content of the latter of 3.3–4.2%. Most brown-coal tars do not have this valuable property. Thus, for example, Ukrainian coals of the Aleksandriisk district, according to the data of M. V. Goftman [6] (UKhIN, Kharkov), give a primary tar with a specific gravity at 50° equal to 1.004. According to Terfil’ev, Baiko, and Yut [10], even after careful settling this tar retained up to 19% water.

Chelyabinsk and Moscow-region coals give tar with a specific gravity close to unity, and likewise one that separates from water only with difficulty.

A characteristic feature of the primary tar obtained is the relatively small amount of carboxylic acids and phenols and the clear predominance of neutral constituent parts, among which paraffin accounts for a large share, causing the tar mass to solidify at 23–24°.

The differences between tar obtained from freshly mined and from weathered coal, as is evident from the table, are not substantial. Next, the obtained samples of primary tar were subjected to distillation, with determination of the specific gravity and the content of unsaturates for each fraction (the amount of unsaturated compounds was determined with the aid of sulfuric acid of specific gravity 1.84). The results are given in Table 14.

Table 14

¹ Determination of the specific gravity of the 6th fraction was carried out at 50°.

The 1st fraction, up to 120°, was initially almost colorless and, on standing, acquired a yellowish-green color. The 2nd fraction, being yellow at first, on standing turned into a reddish-brown liquid. The 3rd and 4th fractions were a reddish-brown viscous liquid.

The 5th and 6th fractions were brown in color and solidify at normal temperature (20°C).

On the basis of the data in Table 14, the yields of crude light products—gasoline (distillation up to 200°) and kerosene (distillation from 200° to 240°)—from the primary tar and calculated on dry coal are given in Table 15.

Table 15

In terms of the yields of the gasoline and kerosene fractions, the tar of Yarskoye coal is close in quality to the tar of Ukrainian brown coals, which give about 20–25% of a gasoline-kerosene fraction on an anhydrous tar basis [10].

However, the value of the products obtained by distillation of the tar is greatly reduced by the content of a large quantity of unsaturated compounds. As is evident from Table 14, each fraction contains more than half unsaturated compounds. Therefore, the gasoline and kerosene separated by distillation gradually darken on standing, owing to the occurrence of polymerization reactions. After treatment of the gasoline with a 15-percent solution of caustic soda and concentrated sulfuric acid, 79% by volume of the original amount of “crude gasoline” remained. Its color remained reddish-brown, owing to resinified substances (polymerizates) dissolved in the gasoline. After subsequent distillation, completely colorless gasoline was obtained in an amount of 53% of the original volume of “crude gasoline.” On storage in the light for several months it acquired only a barely noticeable pale-yellow coloration.

The use of the light fractions from tar distillation as motor fuel requires their preliminary purification from unsaturated compounds. The considerable decrease in the yield of gasoline and kerosene after such purification, and the large consumption of alkali and sulfuric acid, are serious obstacles to the practical use of these products and bring to the fore a more advanced method of hydrogenation of the tar, in which high-quality products are obtained and yields are considerably increased. By hydrogenation it is possible to convert about 70% of the primary tar into light motor fuel, which would already amount to a yield of about 11–12% on dry coal.

The final fractions from tar distillation are of substantial interest. They are rich in paraffin. The sixth fraction from the tar obtained from freshly mined coal has a solidification temperature of 29.5°, and that from oxidized coal—26.6°. It is likely expedient to use this fraction for obtaining paraffin, and to send the residue (oil) to hydrogenation. Undoubtedly, the phenols contained in the tar in an amount of 15–16% are also valuable; they can be separated by the usual method. The pitch obtained is quite suitable for use in road construction.

Conclusions

1. The brown coal of the Yarskoye deposit is high-ash, with an ash content of up to 31–17%, and in the freshly mined state it has a high moisture content, reaching 53.9% in the samples studied, which considerably lowers its quality as a fuel; however, after drying and briquetting the coal can provide a quite satisfactory domestic fuel and a fuel for gas generators.

2. In its structure the coal is mainly an earthy, easily crumbling mass with a small admixture (about 10%) of woody inclusions. The pieces of coal are of low strength and can easily be crushed and converted into dust, which is favorable for coal preparation before briquetting.

3. As a chemical raw material for semi-coking, Yarskoye brown coal is of undoubted interest, giving a yield of primary tar of up to 17.5% on dry coal and up to 24.8% on an ash-free basis.

4. The semi-coke obtained in semi-coking can well be used for combustion in the pulverized state.

5. Primary gas is obtained in an amount of 80 to 105 m³ from 1 ton of dry coal, with a content of \(CO_2 + H_2S\) of about 50%, and with the calorific value of the raw gas about 2800 kcal/m³. The calorific value of the gas can easily be considerably increased by purifying it from \(CO_2\). The gas obtained after such, even partial, purification, with a calorific value of not less than 4000 kcal/m³, is already a valuable fuel. Upgrading of the gas is conveniently carried out by applying fractional withdrawal of the gas, directing the first fractions to the decomposition of the phenolates obtained from the tar.

6. Primary tar on distillation gives about 10% of distillate up to 200° (crude gasoline) and about 15% of distillate from 200 to 250° (crude kerosene), which constitutes a yield of crude light products of about 4.4% on dry coal (for the freshly mined sample).

7. Crude gasoline and kerosene contain more than 50% unsaturated compounds and phenols, which rules out the possibility of purification with sulfuric acid.

8. Semi-coking followed by hydrogenation of the tar appears to be the most expedient method for obtaining motor fuel, as a result of which 11–12% of light products on dry coal can be obtained. In addition, under the general technological scheme the tar can serve as a source for obtaining paraffin, phenols, and probably lubricating oils from it. Primary gas and semi-coke can well be used as fuel or as technological raw material for carrying out the process of synthesizing liquid fuel.

9. When lying in the open air, the coal deteriorates in quality, and the yield of the most valuable product—tar—is considerably reduced.

10. Study of samples taken from various points of the adit indicates uniformity of coal quality over the extent of the seam.

11. During semi-coking the coal does not cake at all, which facilitates the choice of furnace for semi-coking. Geissen furnaces should be considered the most suitable for this purpose.

12. In the future it is necessary to carry out a study of the hydrogenatability of the primary tar, as well as to undertake geological exploration work to clarify the reserves.

13. If reserves are sufficient, the coal could serve as raw material for the production of artificial liquid fuel and other chemical products needed for Tomsk Oblast, provided that its average ash content is not too high.

References

1. Burov M. N. Chemical processing of brown coals of the USSR. Collection of articles. 1938.

2. Burov M. N. Chemical processing of fuels of the USSR. Collection of articles. 1946.

3. Williams V. R. Brown coals of the USSR. 1936.

4. Veis M. Drying of coal. 1934.

5. Voskresenskii A. A., and Novikov A. Z. Semi-coking of slack coals of the Moscow Basin. Journal Chemistry of Solid Fuel, No. 2, 1938.

6. Goftman M. V. Semi-coking of coals of the Moscow Region. 1928.

7. Müller F. and Druse K. Technical gases. Russian translation. 1934.

8. Popov V. S. and Gébler I. V. The Yarskoye brown-coal deposit. Bulletin of the West Siberian Geological Administration, No. 2, 1939.

9. Solodovnikov P. A. Thermal treatment of Moscow-region coals for obtaining household gas and hydrogen. 1931.

10. Terfil’ev I. A., Boiko A. A., and Yut N. S. Semi-coking of brown coals from Ukrainian deposits. Journal Chemistry of Solid Fuel, No. 3, 1933.