过程装备优化设计：合理利用公用工程

1、过程装备优化设计4 合理利用公用工程Multiple Utilities(1)由问题表格法绘制总组合曲线(2) 由组合曲线绘制总组合曲线(3) 总组合曲线的意义 描述热流量沿温度的分布； 需要补充热量的温位； 可以回收热量的温位； 夹点上方热阱，只需要热公用工程； 夹点下方热源，只需要冷公用工程； 过程能量综合的背景。The Grand Composite gives the hot and cold utility requirement of the process both in ENTHALPY and TEMPERATURE(2) 蒸汽低压蒸汽(P2.5MPa，T400）中压蒸汽(2

2、.5MPaP6MPa，400T450)高压蒸汽(6MPaP14MPa，460T540)超高压蒸汽(14MPaP17MPa，540T570)亚临界压力蒸汽(P1718MPa，540T570)超临界压力蒸汽(P18MPa, T570)(2) 蒸汽(2) 蒸汽(2) 蒸汽(3) 烟气Pinch temperature might be limiting stack temperature.CPminTTFT = theoretical flam temperatureTacid dew= acid dew pointTo = ambient(3) 烟气(4) 制冷剂四氟乙烷(R134a)：-26.3

3、氟利昂-12(R12，CF2Cl2)：-29.8氨(R717)：-33.3氟利昂-22(R22，CHF2Cl)：-41丙烷(R290)：-42二氧化碳(R744)：-78.5乙烯(R1150)：-103.9甲烷(R50)：-161.5液氮：-196.64.4 公用工程夹点4.4 公用工程夹点4.4 公用工程夹点The composite curves give the true pictureWe need to add the utilities back inForm Balanced Composite Curves平衡组合曲线平衡组合曲线Each utility pinch creat

4、es an additional design region within which only the appropriate utility is used.SummaryThe grand composite curve can be constructed directly form the problem table algorithm.Grand composite curve shows utility requirements in enthalpy and temperature terms.Temperature differences built into the con

5、structionBest tool for utility placement.Balanced composite curves give the true picture (after utility selection)5 门槛问题Threshold Problems5. 门槛问题5. 门槛问题5. 门槛问题5. 门槛问题门槛问题与夹点问题门槛问题过程系统只需要一种公用工程物流。门槛问题和夹点问题Design for Threshold Problems门槛问题的设计门槛问题的设计ExampleH452.20428.18505.56320.00528.00413.00340.60Exa

6、mple门槛问题的设计门槛问题的设计Whether or not they remain Threshold Problems, usually depends on the economy of scale门槛问题的设计SummarySome problems exhibit a threshold-only hot or cold utility required.True threshold problems have large temperature driving forces and no pinch.Most threshold problems turn out to be pinched problems after multiple utilities used.Working Ses