US1721997A - Low-temperature distillation of carbonizable material - Google Patents

Description

Patents July 23, I929.

areas? LOW-TEMPERATURE DISTILLATION 01E CARBONTZA BLE MATIAL.

No Drawing. Application filed August 2 1921,

Serial No. 494,785, and in Germany July 28,1919.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 19 21, 41 STAT. Eh, 1313.)

The present application'relates to a new or improved process for the improvement of in ferior brown coals and peat, and deals in particular with the treatment of materials,

5 such as very woody lig'nite of fibrous or fragmentary structure, which can only be briquetted with difficulty, if at all.

The process consists in subjecting the material to a restricted dry distillation in which it is not completely eoked butonly attains an intermediate condition between coal and coke. The completely distilled coke obtained from such material is somewhat inferior, partly on account of its lOW infiammability and the 1 consequent restricted usefulness, and partly by reason of its usually low cohesion.

According to the present invention a readily ignitable and valuable heating material with a heating valueof about 6000 calories or more, can be obtained from a erudecoal of barely 2000 calories, by interrupting the coking process prior to its final stage. The process is carried out as follows (the temperatures given are centigradel The more or less pre-driedcrude coal is first freed from water, and the bulk of the carbon dioxide at a progressively increasing temperature. As soon as the temperature exceeds about 250 deg., the first tarry distillates' can be observed, and at about 270 deg, an ex othermic reattion begins, b r means of which the distillation is continued. By this means "and the further application of heat, additional quantities of low-temperature tar pass over into the receiver. The heating is then increased until the temperature is between 290 and 350, during which interval the lowtemperature tarin all the coals examined'is driven over. A few kinds of coal require temperatures of up to 350 deg. At this point the heating is interrupted after the lowtemperaure tar has passed over. The resulting material is a valuable long-flame fuel,

which is more particularly useful for furnaces. A maximum yield of valuable lowtemperature tar is obtained as a by-product. In view of the poor heat conductivity of the material to be treated, it may be advisable in the interests of uniform heating-especially in retorts of large diameterto supplement 4 the external application of heat by an internal heating with superheated steam.

However, in order that the yield of fuel may not suffer in the interestsof'the yield of gas, not more than 10% of steam (based on the weight 'of the material under treatment) should be used. This small quantity of steam issufiicient to ensure that the charge will be warmed through in a uniform manner and to accelerate the removal of the distillation gases from the retorts so as to prevent overheating. In addition, the yield of ammonia and acetic acid, together-although to a smaller extentwith that of methyl alcohol, is increased.

I claim l The process of treating moist, solid carbonizable material containing appreciable quantities of oxygen and capable of relea's-' ing by chemical decomposition substantial quantities of tarry material when heated to temperatures between 250 C. and 350 C. and substantial quantities of tarry material of a different character when heated to temperatures above 850 C. which comprises, heating" said material in a distilling retort to dry the same, progressively raisingthe temperature thereof up-to about 350 C. and then cooling the residue while removing vol'atilized .material from the retort while said residue still contains a major portion of tar forming material capable of releasing tar at temperatures above 350 Q. 1

In testimony whereof ll affix my signature.

near. w. a n. races.