冷却水系统计算课件.ppt

冷却水系统计算;Content;Cooling Tower Type;Function of Cooling Towers;Tower Design Considerations;Cooling Tower Heat Transfer Mechanisms;Review of Basic Cooling TowerDefinition of Terms;Cooling Tower Water Balance;Cooling Tower Terms;Wet Bulb;Psychrometers;;Heat Exchange;Evaporation;Tower Drift;Cycles of Concentration;浓缩倍数CR ;Cycles of Concentration;Increasing the Cycles;CR 的计算方法;CR 的计算方法;CR 的计算方法;CR 的计算方法;CoC 的计算实例;Calcium Cycles ≈ Actual Cycles;Calcium Cycles ? True Cycles;Calcium Cycles ? True Cycles;Cycles of Concentration;Cycles of Concentration;Cycles of Concentration;Calcium and magnesium CR showing precipitation of calcium carbonate;Flow Vs Cycles;If we increased COC from 3.0 to 5.0 time, how many percentage of water will be saved? If current chemical dosing rate is 100ppm, and when COC is increased to 5 time, chemical dosing rate will be also increased to 120ppm. How many percentage of chemical will be saved?;Cooling Tower Terms;HOLDING TIME INDEX;Importance of HTI;Importance of HTI;;;Cooling System Workshop;The Cooling System Material Balance;基本概念之定义 (一);4) 排污量--BD (m3/hr) blowdown rate, includes leakage 从系统中不断排出一定量水，以保持系统中离子浓 度的要求，称之为排污量。 5) 温差--?T (?C) temperature drop through the tower 冷却塔入口温度和水池出口温度之差。 6) 循环水量--RR (m3/hr) RR = recirculation rate 系统中单位时间内循环水的量。 7) 浓缩倍数--CR = cycles of concentration 指补给水与排污水的浓度比。 ;8)保有水量--HC (m3) Holding Capacity or System Volume 指冷却塔、水池、换热器、管道、设备保有水量的总和。 9)循环周期--RT (分钟/周期) 循环水水在冷却水系统中循环一周所需时间。 10)半衰期--HTI (hr) Holding Time Index 该计算数值表示系统中化学品或补给水减少到初始值的 50%所需时间。 11) 总溶固--TDS (ppm) 水中含可溶物质量总和。 ;12)腐蚀率 (mm/a 或 mpy,mdd) 指示金属的腐蚀速度。通常用挂片来测试。 13)污垢沉积速率 (mg/月/cm2) 表明循环水系统中污泥沉积和结垢的综合趋势。 14)碳酸钙饱和指数--LSI 该指数用来确定CaCO3的成垢趋势。 LSI=pH - pHs 0 成垢趋势 LSI=pH - pHs = 0 中性 LSI=pH - pHs 0 有腐蚀趋势 ;Cooling Tower Evaporation Rate;Cooling Tower Evaporation Rate;Cycles of Concentration = Make-up Blowdown Make-up = Blowdown* + Evaporation Rate Make-up = Evaporation Rate x Cycles (Cycles –1) HTI = 0.7 x Sys