水的基本化学性质.ppt

水的基本化学性质 目的, 过程, 获益 Purpose, Process, Pay-off, cont’d Water, the Universal Solvent HYDROLOGICAL CYCLE Expression of Results Equivalent Weight Example Equivalent in Terms of CaCO3 Equivalent in Terms of CaCO3, cont’d Example Workshop Exercise Definition and Units of Conductivity Commonly Used Units of Conductivity and Their Relationships Effect of Temperature on Conductivity Definition of Acidity Definition of Alkalinity Effect of pH on Alkalinity and Acidity P Alkalinity M Alkalinity or Total Alkalinity P(BaCl2) Alkalinity in Boiler Water P(BaCl2), cont’d pH - Its Estimation in CW Systems Estimation of pH, cont’d Estimation of pH, cont’d Estimation of pH, cont’d Estimation of pH, cont’d- Workshop Exercise Alkalinity for Silica Control in Boilers Alkalinity for Silica Control, cont’d P(BaCl2) for SiO2 Control in Boilers P(BaCl2) for SiO2 Control, cont’d “Rule of Thumb” for P(BaCl2) in Terms of TDS - SiO2 Control in Boilers “Rule of Thumb”, cont’d Rule of Thumb, cont’d Example Workshop Exercise Indices to Predict Corrosion and Scaling Potential Indices, cont’d Indices, cont’d Indices, cont’d Indices, cont’d Indices, cont’d Indices, cont’d Indices, cont’d Workshop Exercise Quiz Quiz, cont’d Quiz, cont’d Quiz, cont’d Temperature has a significant effect on conductivity, and this expression allows you to estimate the effect. This is particularly important if a non-temperature compensated conductivity meter is being used, as all readings should be converted back to the same basis(20 or 25oC). Acidity is not as important as alkalinity for water chemists, but at least this much should be known. Alkalinity seems to be a difficult concept to grasp, but this slide and the next should help. Spend plenty of time discussing these concepts, until everyone is satisfied they understand what alkalinity is. This simple chart shows what alkalinity/acidity species exist at any pH or over any pH range. This chart should be committed to memory and completely understood as it is