(674b) Alternative Production of Calcium Carbide

Chinedu J. Umeozor and Thomas R. Marrero

Department of Chemical Engineering, University of Missouri, Columbia, MO 65211

ABSTRACT

The primary purpose of this research is to determine the effect of ultrafine reactant particle size on the preparation of calcium carbide. Reactants are lime and biochar, a relatively pure source of carbon. The carbon has a particle size distribution of 10 to 100 micrometers and reacts with lime in a bench-scale furnace. Reaction temperatures are above 1000^oC. The anticipated results of these bench-scale studies are (1) the effect of ultrafine particle size on calcium carbide yields as a function of temperature, and (2) determination of the costs/benefits of biochar in the preparation of calcium carbide. These results are significant with respect to calcium carbide quality and the resulting environmental impact from CO₂ emissions for calcium carbide manufacture.

Current CO₂ emissions associated with calcium carbide production are about 1/2 metric ton per ton of calcium carbide. With the global production of calcium carbide exceeding 15 million tons per year, CO₂ emissions to the atmosphere exceed 8 million tons per year. In addition to this issue, for each metric ton of calcium carbide produced, the actual energy consumed is from 3000 to 3800 kWh which differs significantly from the theoretical energy requirement of 2000 kWh. The difference between the actual energy consumed and theoretical energy required to produce a ton of calcium carbide is therefore large and provides an opportunity to reduce the required energy for calcium carbide production and also reduce the associated CO₂ emissions to the atmosphere. This opportunity is addressed in this study by using purer reactants and ultrafine particles. The ultrafine particle size reactants form a eutectic of calcium oxide and carbon which allows calcium carbide manufacture at 500^oC less than normal practice.