HIGH CAPACITY COCONUT SHELL CHAR FOR CARBON MOLECULAR SIEVES

摘要

A coconut shell char having a high oxygen volumetric capacity is provided by crushing and sizing coconut shells to form granules which are then heated in flowing inert gas at a temperature ramp rate of about 2 to 12.degree.C per minute to a peak temperature of 775 to 900.degree.C which is then held so that the total heating time is up to 8 hours and thereafter the granular char is cooled in an inert gas atmosphere. The granular char thus produced is oxygen selective in air separation without further modification to narrow the openings of its micropores and has an oxygen volumetric capacity in excess of 8.0 cc/cc. Further modification of this char is provided by contacting it with an oxidizing atmosphere of carbon dioxide or a mixture of inert gas and carbon dioxide, H20 or 02 at temperatures ranging from 650 to 900.degree.C until the gasified char has been altered so that its volumetric oxygen capacity is greater than 9.0 cc/cc. The coconut shell char can be further modified directly as prepared or following a gasification procedure by treatment with volatile carbon-containing organic compound which is pyrolyzed to form carbon which reduces the effective pore openings of the original or gasified char.