Proper operation of semibatch reactor for chemical reaction followed by precipitation

In the case of a chemical reaction followed by precipitation in a semibatch reactor, there are possibilities that no precipitate deposits because the concentration of chemical reaction product does not exceed its solubility, and the coprecipitation or adsorption of impurities contaminates the precip itate as the concentration of reaction product becomes too high temporarily . Proper operation to keep the state in a semibatch reactor suitable for pr ecipitation is established with isocline analysis on the phase plane, as fo llows: (1) The flow rate of feed is increased with time exponentially so th at the concentrations of reactant and reaction product in a semibatch react or have a pseudo-steady state. (2) The concentration of reactant in feed, w hich keeps the concentration of reaction product at a pseudo-steady state o ver its solubility can be calculated from an isocline equation. (3) If the concentration of reactant in the reactor at the beginning of the operation is not higher than that of the pseudo-steady state, then the concentration of reaction product approaches the pseudo-steady state with time monotonous ly, not going beyond the pseudo-steady state.