304,301. Standard Oil Development Co., (Assignees of Haslam, R. T., and Russel, R. P.). Jan. 19, 1928, [Convention date]. Grant of Patent opposed. Hydrogenation, destructive. -Carbonaceous materials e.g. oils, coal suspensions &c. are converted into hydrocarbons of low boiling point by bringing them into intimate contact with hydrogen at high temperatures and pressures while passing through a heating zone, the mixture being then treated in a reaction zone. A portion of the partially converted material may also be withdrawn from the reaction zone, mixed with hvdrogen, reheated and returned thereto. The reaction is preferably conducted in the presence of catalysts e.g. metallic oxides which are circulated with the oil or introduced into the reaction chamber. The plant comprises a tubular heater 4, an insulated reaction drum 1 and heat interchangers and condensers 12, 20, 25. The crude oil is supplied by a pump 7 as desired either through a line 6 to the coil 4 or through a bye-pass 6<a> direct to the drum 1 and is preheated by passing through the exchangers 20, 25. Hydrogen or gases containing hydrogen enter the system through a line 10 and after preheating in the exchanger 12 are mixed with the oil either in a mixer 15 or in the pipe 9. The vapours produced pass off through a pipe 19 and are partially condensed in the exchangers 12, 20, 25, the condensate in the exchanger 12, 20 being returned to the drum 1 through a line 22, the mixer 15 and the heating coil 4. In the plant described the catalyst is circulated in suspension in the oil but in the modification shown in Fig. 2 a second reaction drum 47 is used in which the catalysts are mounted on trays 48. The primary drum is provided with a stirrer 41 and an electric heater 43 while hydrogen is injected directly into both drums through spray heads 45, 54. The final condensates are collected in receivers 27, 33 the surplus hydrogenating gases being separated in a drum 31 and purified before return to the plant by passage through scrubbers 36, 37 containing alkali solution and petroleum respectively for the removal of hydrogen sulphide and methane.