US1965513A - Process for improving coal material - Google Patents

Description

' loidal properties vthe heating riegulable increase in Patented July 3, 1934 PROCESS FOR IMPROVING COAL MATERIAL Apollo Ruiika, Usti Nad Labem, Krasnobrezenska, Czechoslovakia No Drawing. Application July 13, 1932, Serial No. 622,362. In Bulgaria August 21, 1931 1 Claim.

As is well known, the drying of many fuels of high water content, particularly the geologically recent varieties, such as, for example, brown coal or lignite, offers great difficulties owing to the colof the same. Particularly great during the drying of lump brown coal and the coarser varieties thereof, which frequently crumble and disintegrate when the drying processes heretofore known are employed.

It is already known to heat brown coal up to the drying temperature for drying purposes by introducing steam under pressure directly on to the material to be dried, and then effecting evaporation of the moisture by releasing the pressure. The employment of this steam introduced directly on to the material to be dried is disadvantageous, since the heat is too rapidly and too suddenly transferred to the coal, with the result'that the outer layers of each lump of coal are heated suddenly and partial evaporation of the moisture contained therein takes place, whilst on the other hand the interior layers do not partake of this rapid heating, and consequently pressure differences arise between the inner and outer layers difliculties arise of the coal, which cause a more or less deepseated disintegration of the lumps.

These drawbacks are removed by the process which forms the subject matter of this invention, and which consists essentially in that the material, partially immersed in supplied water, is heated in the pressure container together with the supplied water to a temperature of 150-250 C. at a pressure of the saturated water vapour v present which corresponds to this temperature, being effected, when employing an external heating medium, e. g. flue gas, by merely heating the lower part of the container filled with supplied water or, when employing direct introduction of steam, by leading the latter merely into the lower part of the pressure container filled with the added water. In the former case the steam is merely formed water, and in the latter case duced saturates itself only from the supplied wa- Eter, so that in both cases the evaporation of the moisture contained in the coal, as well as the superheating of the water vapour, are prevented with certainty. The pressure in the container is thereupon released and as a result a solid miiip'roduct, substantially moisture-free and non-colloidal is obtained.

According to the invention, therefore, not only are the above-mentioned drawbacks practically completely removed, but also a gradual, readily the temperature and the pressure, suitably adaptable to the properties of the coal to be dried, and therefore a gradual, uniformly increasing, non-detrimental heating of the material is ensured and the formation of vapour from the moisture contained in the coal is avoided as well as all superheating of the water vapours, both of which bring about the differences in tension between the inner and outer coal layers of each lump of coal. Furthermore, a not inconsiderable diminution in the ash and sulphur content is brought about, varying according to the properties of the coal.

A further substantial advantage of this process consists in the possibility of employing superheated steam, by which means the economy of the process can be raised considerably.

It has also been found that the very high pressure of the water vapours contained in the colloidal coal material is the main cause of the disintegration of the fuels during the drying of the same.

The water vapours can escape from the colloidal coal material only with difiiculty, and break it up in the case of deep penetration if this colloidal property has not previously been removed, it being borne in mind that the consistency of the material is maintained. This is brought about by heating the part of the pressure container filled with a suitable quantity of supplied water, as a result of which this colloidal quality of the coal, and its capability of binding moisture, is destroyed. The quantity of water added to the fuel depends on the moisture content of the material and its physical properties, and also on the heating medium employed for the heating, and on the desired final temperature and the desired pressure, there being in no case any superheating of the water vapours in the container, that is to say, there must always be a quantity of supplied water left during the heating, as well as after the attainment of the final temperature, such that the conditions of saturated water vapour always prevail in the pressure container.

The height of the temperature depends on the be dried. Preferably the are employed, which, however, composition temperature of the coal mass, i. e. they must notresult in any deep-seated decomposition of the coal material. 1

The coal treated according to this process loses its colloidal quality and separates out'the greater part of the moisture contained therein Without any considerable decomposition taking place.

I PATENT OFFICE ter and the portion of the at a temperature selected from the range 150- and under a pressure of the saturated water vapour present which corresponds to the selected temperature, and thereupon releasing the pressure.

' APOLLO RUZIC A.

fuel immersed therein