Eric L. Tollefson

Preparation of activated carbon from Canadian coals using a fixed-bed reactor and a spouted bed-kiln system

Abstract Several western Canadian coals (Bienfait lignite, Roselyn, Montgomery, Atlas-Century and Egg Lake subbituminous coals, and Coal Valley and Smoky River bituminous coals) were activated with steam to produce granular activated carbons. Activation times and temperatures were 0.5–4.0 h and 650–850°C. The iodine number was used as a primary indicator of product quality. Activated carbons having iodine numbers of ≥ 500 mg g−1 carbon were produced from each coal except Smoky River. Bienfait lignite was found to be relatively reactive, the highest iodine number developed being 545 at a yield of 29 wt% and at 650°C. Products from Montgomery and Atlas-Century coals showed iodine numbers of 620 and 579 at yields of 36 and 37 wt% respectively, at 700°C. When activated at 650°C for 3 h, Roselyn coal gave a product with an iodine number of 730. The products from Coal Valley coal, the least reactive, had an iodine numbers which increased from 370 on activation at 650°C for 2 h to 571 on activation at 760°C for 1.0 h, the product yield decreasing from 59 to 45 wt%. The high ash of the products, 23–67 wt%, limits their quality. The performances of fixed-bed and spouted bed-kiln reaction systems were compared by analyses of the properties of the products from Coal Valley coal. The fixed-bed system generally gave products with higher sorptive capacities under operating conditions which caused higher carbon burnoff.

Desulphurization of a fluid coke similar to the Athabasca oil sands coke

Abstract Almost complete desulphurization of a high-sulphur fluid coke was achieved by impregnating the coke with suitable alkaline reagents followed by high-temperature calcination in an inert atmosphere and subsequent leaching of the coke to remove soluble metal sulphides formed during calcination. Sodium hydroxide and sodium carbonate were found to be the most effective bases. Sodium sulphide was detected in the calcined, non-leached coke by X-ray diffraction. Methane, carbon monoxide, carbon dioxide, ammonia and water, in addition to hydrogen sulphide, were detected in the gaseous product stream by gas chromatography. Flow rate of the inert gas and the particle size of the coke employed in this investigation had no effect on the extent of desulphurization. A maximum desulphurization was observed at a calcination temperature of 850 °C.

Activation of Canadian coals in a fixed-bed reactor and an internally stirred horizontal kiln

Activation of a lignite, a subbituminous coal and a high-volatile bituminous coal was studied using a fixed-bed reactor and an internally stirred horizontal kiln (ISHK), the latter being designed to control dusting problems encountered in handling finely divided coal. The properties of the activated carbons were determined by measuring iodine, methylene blue and phenol numbers, specific surface areas, bulk density, mercury and nitrogen porosities and ash and mineral contents. The lignite, activated at lower temperatures (∼700°C) in the ISHK system, developed a surface area of ∼500 m2 g−1 with most of the adsorptive surface associated with micropores of radii 700 m2 g−1 and a methylene blue number of 175, higher values than the best obtained with the lower-rank coals. The activation temperature needed to achieve these results with this higher-rank coal is ∼150 K higher than that for the low-rank coals.

The Role of Catalysis in Achieving a Sustainable Society

Abstract This paper describes changes occurring in the environment which could radically alter the nature of society in the decades ahead unless corrective action is taken to create sustainable conditions. The upward trend in carbon emissions together with the effects of other greenhouse gases on the average global temperature are considered and suggestions made as to how a sustainable state might be achieved by replacing non-renewable energy sources with renewable ones such as trees, biomass and hydrogen as well as hydro, solar, tidal and wind.