過程裝備優(yōu)化設(shè)計(jì)：合理利用公用工程

1、過程裝備優(yōu)化設(shè)計(jì)4 合理利用公用工程Multiple Utilities(1)由問題表格法繪制總組合曲線(2) 由組合曲線繪制總組合曲線(3) 總組合曲線的意義 描述熱流量沿溫度的分布； 需要補(bǔ)充熱量的溫位； 可以回收熱量的溫位； 夾點(diǎn)上方熱阱，只需要熱公用工程； 夾點(diǎn)下方熱源，只需要冷公用工程； 過程能量綜合的背景。The Grand Composite gives the hot and cold utility requirement of the process both in ENTHALPY and TEMPERATURE(2) 蒸汽低壓蒸汽(P2.5MPa，T400）中壓蒸汽(2

2、.5MPaP6MPa，400T450)高壓蒸汽(6MPaP14MPa，460T540)超高壓蒸汽(14MPaP17MPa，540T570)亞臨界壓力蒸汽(P1718MPa，540T570)超臨界壓力蒸汽(P18MPa, T570)(2) 蒸汽(2) 蒸汽(2) 蒸汽(3) 煙氣Pinch temperature might be limiting stack temperature.CPminTTFT = theoretical flam temperatureTacid dew= acid dew pointTo = ambient(3) 煙氣(4) 制冷劑四氟乙烷(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 公用工程夾點(diǎn)4.4 公用工程夾點(diǎn)4.4 公用工程夾點(diǎn)The composite curves give the true pictureWe need to add the utilities back inForm Balanced Composite Curves平衡組合曲線平衡組合曲線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 門檻問題Threshold Problems5. 門檻問題5. 門檻問題5. 門檻問題5. 門檻問題門檻問題與夾點(diǎn)問題門檻問題過程系統(tǒng)只需要一種公用工程物流。門檻問題和夾點(diǎn)問題Design for Threshold Problems門檻問題的設(shè)計(jì)門檻問題的設(shè)計(jì)ExampleH452.20428.18505.56320.00528.00413.00340.60Exa

6、mple門檻問題的設(shè)計(jì)門檻問題的設(shè)計(jì)Whether or not they remain Threshold Problems, usually depends on the economy of scale門檻問題的設(shè)計(jì)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