降膜蒸发器改造热平衡计算.docx

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1、蒸发热平衡计算计算的原始数据1）新蒸汽使用压力P=5bar（绝压），T=155oC,潜热2102kJkg;2）原液N175g1,质量分率13.8%,比热0.825KCaMkgC,to=85C,P=1270kgm3;3）出料浓度N255g1,质量分率18.5%,比热0.766Kca1kg,ti1=90C,P=1375kgm3;4）末效（第VI效）压力P=0.1bar（绝压），二次蒸汽温度T6=46C,汽化热2387kJkg;5）传热系数（WC）:Ki=1980,Kn=1580,Km=1580,Kiv=1400,Kv=917,Kvi=1024,K强二750；6）传热而积（n?）：Fi=1500,F

2、n=1500,Fiii=1500,Fiv=1500,Fv=3750,Fv=3750,F强=580;7）温度损失：蒸发器IIIIIIIVVVI沸点升高131199815沿管损失11111合计14121010915总温度损失70C；8）为简化计算过程，计算时没有考虑冷凝水自蒸发产生的二次汽及热损失，而把它们考虑为相互抵消；9）按处理流量Ioookg/h进行计算。计算1.蒸水量W总=IOOO（175/1270）/（255/1375）=235.8kgh2、总温度差At总=155-46=109C3、蒸发水量的分配（第一次逼近值）W1=（W1+W2+W3+W4+W5+W6）K（K+K+Km+Kv+Kv+K

3、v）=235.8X1980/（1980+1580X2+1400+917+1024）=55.1kg/hW2=W3=W1KK=55.115801980=44.0kghW4=W1KvK=55.1X14001980=39.0kghW5=W1KvK=55.1917/1980=25.5kg/hW6=W1KvK=55.11024/1980=28.5kg/h4、有效温差t有=t总-t损=1O9-7O=39C5、有效温差分配（第一次逼近值）At1=t2=t3=t4=t5=t6=39/6=6.5IIIIIIIVVVII闪II闪In闪加热蒸汽温度155134.511699.683.167.6161123106948

4、166106.59790有效温差6.56.56.56.56.56.5沸点升高13/3011/139/69/48/215/3二次汽温135.5117100.584.168.646.1度12410795826757沿管损失11111加热蒸汽热焰KCa1Zkg658651645.8638.8632625.6加热蒸汽潜热502516530540549.2557.4KCa1/kg溶液沸点148.5128109.593.176.661.1130111.595.1二次汽焙656649644636629.7623650.6644637.6二次汽潜执八、508522533543553561520.1532.15

5、42.06、各效浓度6=GB始/(GW)=IoOoX175/1270/(1000-28.5)=14.6%5=0.5(1000-28.5)0.1460.5(1000-28.5)-25.5=15.4%(送入蒸发系统的原液全部进入VI效蒸发器，经V1效蒸发浓缩后，分别各以50%的液量送入V效和HI效。)a4=0.5(1000-28.5)-25.50.154/0.5(1000-28.5)-25.5-39=16.8%a3=0.5(1000-28.5)0.1460.5(1000-28.5)-44.0=16.1%a2=0.5(1000-28.5)-44X0.1610.5(1000-28.5)-44-44=1

6、7.9%a1=0.5(1000-28.5)-44-44X0.1790.5X(1000-28.5)-44-44-55.1=20.8%7、各效蒸水量1)第V1效热平W55=W66,+FC(t6-t)W5=W6561+1OOO0.825(61.1-85)557.4=w6-35.4W5=W6-35.42)第V效热平W44=W55,+0.5F6C6(t5-t6)=W551+O.5(FC-W6)(t5-U)=(W6-35.4)553+0.5(1OOOX0.825-w6)X(76.6-61.1)w4=(w6-35.4)553+0.5(1OOO0.825-w6)(76.6-61.1)549.2w4=0.993

7、w6-243)I闪热平Fct=FiCit+wHFiCi=fc-wFc(t-t)=wF1C1=O.5F6C6-W1-W2-W3=O.5(FC-W6)W1W2W3(忽略闪蒸进入的水量)0.5(Foco-we)-w-w2-w3(t-t)=wrWI=0.5(IOOO0.825-w6)-w1-w2-w3(148.5-130)/520.1Wi=14.7-0.018W6-0.036(w1+w2+w3)Wi=14.7-0.018X28.5-0.036143.1=14.7-0.018X28.5-0.036143.1=9kgh4)闪热平FCt=FCt+wHFiiCii=fc-wFici(t-t)=wrO.5(Fo

8、co-W6)-w1-w2-w3-w(t-t)=wrWii=0.5(10000.825-w6)-w-w2-w3-w(130-111.5)/532.1Wii=14.3-0.017w6-0.035(w+w2+w3wi)Wii=14.34-0.017x28.5-0.035x(55.1+44+44+9)=8.5kg/h5)山闪热平FC11tH=F1HC111t111+WH1H1IIFiiiciii=fc-wFiicii(t-t)=wrO.5(FC-W6)-W1-W2-W3-WI-W(t11-t111)=WIIiriI1win=0.5(IOOOX0.825-w6)-w-w2-w3-w-w(111.5-95

9、.1)/542win=12.5-0.015W6-0.03(w1w2+w3+w+w)Win=12.5-0.015x28.5-0.03(55.1+88+9+8.5)=7.3kg/h6)第IV效热平W33WI1HI=W4r4,+F5C5(t4-t5)w3r3+wH=w4r4,+F5c5(U-t5)W3r3+WIHi=W441+O.5(FoCO-W6)-W5(t4-t5)W33=W44,+O.5(FC-W6)-W5J(t4-t5)-WHI=543(0.993W6-24)+0.5(1OOO0.825-w6)-w6+35.4(93.1-76.6)-7.3637.6=539.2we-13032+6806.3

10、-8.25w6-16.5w6+584.1-4654.5=514.45we-10296W3=(514.45W6-10296)/540w3=0.953w6-19.17)第III效热平W22W1H1I=W33,+O.5F6C6(t3-t4)=W33,+O.5(FC-W6)(t3-U)W22=W33,+O.5(FC-W6)(t3-t4)-WH=533(0.953W6-19.1)+0.5(1OOO0.825-w6)(109.5-61.1)-8.5644=508we-IO180.3+19965-24.2w6-5474=483.2w4310.7w2=(483.2w6+4310.7)530=0.91w6+8.

11、18)第II效热平win+wHi=W221+F3c3(t2-t3)F3C3=0.5FC6-W3=O.5(FC-W6)-W3W1+W1H1=W221+O.5(FC-W6)-W3(t2-t3)=522(0.91W6+8.1)+0.5(1OOO0.825-w6)-0.953w6+19.1(128-109.5)=475w+4228.2+7631.3-9.25w6-17.6w6+353.4=448.2w6+12212.9win=448.2w6+12212.9-9650.6=448.2w6+6537.5wi=(448.2w6+6537.5)516=0.869w6+12.39)第I效热平Dr=w,+F2c2

12、(t1-t2)F2C2=O.5(FC-W6)-W3-W2Dr=w,+O.5(Foco-W6)-w3-w2(t1-t2)=508(0.869w612.3)+0.5(1OOO0.825-w6)-0.953w6+19.1-0.91W6-8.1(148.5-128)=441.5w6+6248.4+8456.3-10.25w6-19.5w6+391.6-18.7w6-166.1=393.1w6+14930.2D=(393.1w6+14930.2)502=0.783w6+29.710)蒸水量W1+W2W3+W4W5+W6=W0.869w+12.3+0.91W68.1+0.953W6-19.1+0.993w

13、-24+W6-35.4+w=235.85.725W6-58.1=235.8W6=51.3kghw5=51.3-35.4=15.9kghw4=0.993X51.3-24=27.0kghW3=0.95351.3-19.1=29.8kghW2=0.9151.3+8.1=54.8kghw=0.86951.3+12.3=56.9kghD=0.78351.3+29.7=69.9kgh10)蒸汽单耗Dw=69.9235.8=0.296kg.汽kg.水8、热负荷Q=Dr=69.9X502=35089kca1q2=wi=56.9X516=29360kca1Q3=w22=54.8530=29044kca1Q4=w33=29.8540=16092kca1Q5=W44=27.0X549.2=14828kca1Q6=w55=15.9X557.4=8863kca19、相对热负荷g2=Q2/Q.29360/35089=0.837g3=Q3/Q=2904435089=0.828g4=Q4/Qi=16092/35089=0.459g5=Q5/Q=1482835089=0.423g