GB357778A - Process for the production of active carbon and gases containing free hydrogen - Google Patents

Abstract

In a process for the production of active carbon and combustible gases containing free hydrogen, commercially cheap materials are employed which are rich in ash or ash-forming constituents, e.g. low-temperature coke or brown coal, the activation temperature being between 400 DEG and 700 DEG C., preferably 500 DEG to 600 DEG C., and the gases employed being mixtures of steam with gas containing free oxygen in amount up to 6 per cent of the mixture. The temperature of the activating gas should not exceed 250 DEG C., preferably 120 DEG to 200 DEG C., and the activating temperature is maintained by the heat evolved during the reaction, external heating being applied only to prevent losses from the reaction chamber or to bring the temperature in certain zones up to the required point. For activation, carbon dioxide may be employed in addition to steam and air or oxygen, and the activation may be carried out at atmospheric, increased or reduced pressure. In operation, the materials to be treated may be stationary or move in counter-current to the activating gases and activation takes place in a zone which, in the case of stationary material, moves forward throughout the mass. The material to be treated is brought to the desired activation temperature over a grate, or if moving, at a certain point, by a blast of hot gas containing oxygen, preferably air. In an example, air at 150 DEG C. was blown for an hour through a layer of low-temperature coke and then a gaseous mixture at 120 DEG C. containing 80 per cent of steam and 20 of air was admitted, the conditions being controlled to give an activating temperature of 500 DEG C. The loss through burning amounted to 18 per cent of the original material and a waste gas containing 21 per cent of hydrogen was obtained. In a second example, a mixture of 95 per cent of steam and 5 of air was used as the activating gas with an activating temperature of 600 DEG C., a waste gas containing 30 per cent of hydrogen being obtained. To avoid loss of heat, when using semi-coke, the converter for the coke may be in direct communication with the activating chambr and the coke may be brought to the desired size before activation. Suitable after-treatment, such as screening, washing with water or chemicals or supplementary activation, may be applied, and the waste gases may be used for heating purposes. Specification 313,154, [Class 90, Non-metallic elements], is referred to.