| 摘要 |
<p>PURPOSE:To prevent scale adhesion in a washing apparatus, by measuring boiler load or a fuel flow amount, the O2-concn. in effluent gas from an oxidation apparatus, the flow amount of a washing liquid to the oxidation apparatus and the flow amount of a seed crystal slurry while manipulating the flow amount of the seed crystal slurry so as to make the operation result of the measured values constant. CONSTITUTION:A boiler load signal measured by a detector 24 is inputted to a function generator A23 while the O2-concn. signal in effluent gas from an oxidation apparatus 5 measured by an O2-densitometer 21 is inputted to a function generator B. The flow amount F of a washing liquid withdrawn to the oxidation apparatus 5 from a washing apparatus 3 and the flow amount F' of a seed crystal slurry supplied to the washing apparatus 3 from the oxidation apparatus 5 are measured by flow meters 27, 32 and the measured values are inputted to a subtractor A33. Operation shown by formula is performed and the flow amount of the seed crystal slurry in an arranged pipe 6 is manipulated so as to make a CaSO4-concn. constant by a regulator 29. The set value of the regulator 29 is set to a predetermined amount or more of the CaSO4-concn. generating no scale.</p> |
