Process for preventing adhesion or caking of coal

In a method of preventing adhesion or caking of solid hydrocarbon-containing raw materials comprising coal which in the presence of hydrogen are partially gasified by hydrogenation gasification in a reaction vessel through which the raw material passes while being heated to a temperature above 700.degree. K., which comprises passing raw materials in particle form downwardly through the reaction vessel, introducing a hydrogen-containing gas into a lower portion of the reaction vessel at a temperature above 700.degree. K. into contact with the raw materials to heat the raw materials to a temperature above 700.degree. K. and to effect hydrogenation gasification of part of the raw materials, the improvement comprising intermittently contacting the particles of raw materials as they pass downwardly through the reaction vessel in the absence of impediments in the path of the raw materials to deflect its flow, in a temperature zone of about 600.degree. to 700.degree. K. with a medium which is at a temperature above 1000.degree. K. in contact with the particles to rapidly heat the surfaces of the raw material particles to above 700.degree. K. by direct contact with the hot medium alone, in the absence of combustion of raw materials with added oxygen to cause the raw material particles to become non-caking in its downward passage through the reaction vessel at a temperature above 700.degree. K.