Black Liquor Gasification with Direct Causticization using Titanates in a Pressurized Entrained-Flow Reactor. Part Ⅰ: Kinetics of the Causticization Reaction

摘要

The kinetics of the direct Causticization reaction between sodium tri-titanate and sodium carbonate in a pressurized entrained-flow reactor has been studied using both pure sodium carbonate and black liquor solids. The experiments were carried out at 900, 950 and 1000℃, at pressures of 0.5 and 1 MPa, in pure nitrogen and in 2% carbon dioxide in nitrogen. The experimental results showed that sodium penta-titanate formation is faster with black liquor than with sodium carbonate, and that the rate increases with temperature. Furthermore, carbon dioxide in the reaction gases slows down the reaction rate and no clear influence of pressure was seen on the reaction rate. The reaction rates for the direct Causticization reaction between sodium tri-titanate and .sodium carbonate was found to be fast enough to be carried out in an entrained-flow reactor system, e.g. a Chemrec gasification system.