Dear Yash
Pottassium Bicarbonate being more soluble than sodium bicarbonate does not get precipitated when CO2 is passed through a concentrated solution of KCl saturated with ammonia.
KCl + CO2 + NH3 + H2O gives KHCO3 + NH4Cl
i.e., pottassium bicarbonate is too soluble to be precipitated by the addition of ammonium bicarbonate to a saturated solution of pottasium chloride
Hence K2CO3 cannot be prepared by Solvay Processs.
Regards
Arun (askIITians forum expert)