KINETICS OF SULFUR CAPTURE

Let's first analyze the rates of decomposition of nahcolite,

2NaHCO₃ —> Na₂CO₃ + CO₂ + H₂O,

and limestone,

CaCO₃ —> CaO + CO₂.

Problem 5.19 in Benítez (op. cit.) is a straightforward calculation of the time necessary for 99% conversion of NaHCO₃ to Na₂CO₃. Most thermal decomposition reactions are indeed 1^st order with respect to the decomposing reactant. The solution is summarized as follows:

A similar analysis is made below for the corresponding decomposition of calcium carbonate, using the data of Borgwardt (AIChE J. 31, 103-111, 1985). From Figure ?? in this paper …

Let's now analyze the decidedly more complex sulfur capture reactions. Example 5.8 in Benítez (op. cit.) discusses the sulfation of sodium carbonate. Here we briefly summarize his analysis.

Sulfation of calcium oxide has been studied much more extensively. Here we analyze the results of only two studies (Borgwardt and Bruce, AIChE J. 32, 239-246; and Bhatia and Perlmutter, AIChE J. 27, 226-234, 1981) and compare them not only with the results for Na₂CO₃ but also with each other.

lrr3@psu.edu (revised 10/18/98)