Process optimization and crystallization kinetics of ammonium sulfate from wet ammonia‐based desulfurization

Abstract

There are some problems in the production of ammonium sulfate, a byproduct of the ammonia desulfurization process, such as small crystal size and uneven distribution. The evaporative crystallization kinetics of ammonium sulfate and the factors affecting the crystallization of ammonium sulfate for improving the quality of ammonium sulfate were studied. The results showed that the largest mean diameter of ammonium sulfate was obtained at a stirring speed of 400 r/min, evaporation temperature of 60 °C, and pH of 5.0. The particle size of the ammonium sulfate increased when the crystal seed was introduced. The metastable region of ammonium sulfate was determined by laser method. The crystallization process of ammonium sulfate was studied using population balance equations and intermittent dynamic method, and the empirical equation of nucleation rate and growth rate of ammonium sulfate crystallization was obtained. This experiment can provide a solution for the problems existing in the production of ammonium sulfate in the process of ammonia desulfurization.

Evaporating crystallization effect of ammonium sulfate at atmospheric pressure under the action of ultrasound

“…By adding large particles of ammonium sulfate, other metal salts, fly ash, and urea [7] , [8] , ammonium sulfate grows on these large particles, which plays a role in inhibiting the spontaneous formation of small grains [9] , [10] , [11] , [12] . Although the addition of seed crystals can produce ammonium sulfate products with uniform particles and large particle sizes, there are strict requirements on the addition time and amount and the process operation is cumbersome [13] . Ammonium sulfate products with larger particles and regular shapes can be obtained at lower temperatures and without crystal seeds when using vacuum crystallization.…”