Neutralising the pH value of acid water - has control to regulate the neutralising agent feed according to comparison of nominal and actual pH values

摘要

To neutralise the pH value of acid water contg. different acid types, with different titration curves, the feed of neutralising agent in a closed control circuit is set by a setting value (y), provided by a control (18) with an integral component from the nominal (w) and actual (x) pH value. The acid components are estimated from the integral part (21) of the control (18), and are taken to give the best feed structure of the neutralising agent. Also claimed is an appts. with a control (18) to set the feed of neutralising agent with at last an integrating behaviour. A comparator (19) gives the control difference (xd) from a preset nominal value (w) and the actual (x) pH value. A system gives the content of the different acid types according to the integral section (21) of the control (18) and matching the control (18). USE/ADVANTAGE - The system is used to assess and modify waste water, esp. from chemical plants, for on-site cleaning before passing into sewage disposal system to prevent damage to bacteria cultures in the sewage tanks. The operation determines the types of acid present, for effective neutralisation, with an accurate pH setting in the water.