3.10、汽轮机内功计算 3.10.1、凝汽流动功wc
wc??c(h0?hc?qrh)?0.5382?(3396.6?2315.6?510.4)?856.49kJ/kg 式中qrh—再热气吸热,qrh?hrh?h2?3537.53-3027.1=510.43kJ/kg 3.10.2、抽器流做功?wa,j
1kgH1抽汽做功wa,1:
wa,1?h0?h1?3396.7-3144.2=252.5 kJ/kg 1kgH2抽汽做功wa,2:
wa,2?h0?h2?3396.7-3027.1=369.6 kJ/kg 1kgH3抽汽做功wa,3:
wa,3?h0?h3?qrh?3396.7-3352.2+510.4=554.9 kJ/kg 1kgH4抽汽做功wa,4:
wa,4?h0?h4?qrh?3396.7-3169.0+510.4=738.1 kJ/kg 其余H5、H6、H7、H8抽汽做功(每kg)的计算同上,结果列于表5。 表5 做功量和抽汽量计算结果 H1 H2 H3 H4(除氧器) 1kg抽汽做功252.4 369.5 554.8 738 (kJ/kg) 各级抽汽量(kg/h) 116242.5 117480 H5 H6 1kg抽汽做功928.5 (kJ/kg) 各级抽汽量(kg/h) 45441 抽汽流总内功?wa,j:
?wa,4??5wa,5??6wa,6??7wa,7??8wa,8 ?wa,j??1wa,1??2wa,2??3wa,3??463030 H7 1191 77781 57090 H8 1451.2 56925 1056 45490.5 16
?0.07045?252.5?0.07120?369.6?0.0382?554.9?0.12584?738.1 ?0.02754?928.5?0.02757?1056?0.04714?1191?0.03450?1451.2
?343.58kJ/kg3.10.3、附加功量?wsg,k
附加功量?wsg,k是指各小汽流量做功之和:
?wsg?(?sg,(6)??sg,(7)??sg,(4)??sg,(5))(h0?hsg,(6))?(?sg,(9)??sg,(10))(h0?hsg,(9)?qrh) ??(8)(h0?hsg,(8)?qrh)
=(0.001362+0.001887+0.0021+0.001669)?(3396.7-3024.3) +(0.0010067+0.001808)?(3396.7-3474+510.4)+0.0008886
?(3396.7-3169+510.55) =4.048
3.10.4、汽轮机内功wi
wi?wc??wa,j??wsg k?856.49?343.58?4.048?1204.12kJ/kg 3.11、汽轮机内效率、热经济指标、汽水量计算
汽轮机比热耗q0:
q0?h0?hfw??rh?qrh?3396.7?1209.06?0.849334?510.4?2621.14kJ/kg
汽轮机绝对内效率?i:
?i=wi/q0?1204.12/2621.14=0.4594 汽轮机绝对电效率?e:
?e??m??g??i?0.985?0.99?0.4594?0.4480 汽轮机热耗率q:
q?3600/?e?3600/0.4480=8035.71kJ/(kWh) 汽轮机汽耗率d
d?q/q0?8035.71/2621.14=3.066 kJ/(kWh) 汽轮机进气量D0;
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D0?1000?d?pe?1000?3.066?530?1624980kg/h 式中 pe—汽轮机额定功率,pe?530MW
检验:汽轮机进气量D0?1645500kg/h,与初选值偏差为1.02%可看作近似相等。 给水量Gfw:
Gfw??c,4?D0?1.0254?1645500?1687296kg/h 凝结水泵流量Gcp:
Gcp??c,5?D0?0.7573?1645500?1246137kg/h 凝汽量Dc:
Dc??c?D0?0.5382?1645500?885608kg/h 第一级抽汽量D1:
D1??1?D0?0.07045?1645500?115925.5kg/h 其余第二级至第八级抽汽量的计算结果,列于表5。 3.12、全厂性热经济指标计算
锅炉参数计算 过热蒸汽参数
由pb?17.42MPa,tb?541℃,查表得过热蒸汽出口比焓hb?3396.8kJ/kg 再热蒸汽参数
锅炉设计再热蒸汽出口压力pr?3.85MPa ,该压力已高于汽轮机排汽压力
??3.567MPa ,故按照汽轮机侧参数。确定锅炉再热器出口压力prhpr?3.292MPa。由pr?3.292MPa 和tr?541℃,查表得再热蒸汽出口比焓hr?3543.9kJ/kg
??hr?h2?3543.9-3027.1=516.8kJ/kg 再热器换热量qrh锅炉有效热量q1
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? q1?(?fw??b1)(hb?hfw)??b1(hb1?hfw)??sp(hb?hsp)??rh?qrh=(0.98514-0.01085)(3396.8-1209.06)
+0.00540(1744.26-1209.06)+0.04026(3396.8-773.8) +0.849324?516.8=2678.92kJ/kg 管道效率?p
?p?q0/q1 =2621.14/2678.92=0.97843 全厂效率?cp
?cp??b?p?e?0.925?0.97843?0.4480=0.4055 全厂发电标准煤耗bs 系数r?q1q1??b?qnf?2678.92/(2678.92-0.925?99.597)
qnf=1.035614 式中—暖风器吸热量,按下式计算:
?)?0.03988(3169.0-697)=99.597kJ/kg qnf??nf(hnf?hnf 相应于1kg标煤的输入热量Qb:
s Qb?29300?r=29300?1.035614=30343.49kJ/kg
s发电标准煤耗bs:
bs?3600?3600/(0.4055?30343.49)=0.29258kg/kW·h s?cp?Qb全厂热耗率qcp
qcp?bs?29300?0.29258?29300=8772.594kJ/kW·h
s全厂供标准煤耗bn:
bs?0.29258/(1-0.07)=0.314602kg/kW·h b?1??sn式中?—厂用电率
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四、反平衡校核
为检查计算结果的正确性,以下做全厂反平衡校核计算。校核目标为汽轮机的内功wi。反平衡计算中的各量均相应于1kg汽轮机进汽。
1.锅炉输入热量qr qr?q1?b?2678.92/0.925=2896.13kJ/kg
2.锅炉损失?qb
?qb?(1??b)qr?(1-0.925)?2896.13=217.21kJ/kg 3.排污损失?qb1
?qb1??b1(hb1?hma)?0.0054?(1744.26-84.1)=8.965kJ/kg 式中hma—化学补充水的比焓hma=84.1kJ/kg 4.全厂工质渗漏损失?qL
?qL=?L(hL?hma)?0.02005?(3397.2-84.1)=66.43kJ/kg 5.厂用汽损失?qpl
?qpl??pl(hpL?hma)? 0.01337?(3169.0-84.1)=41.25kJ/kg 6.凝汽流冷源损失?qc
?)?0.5382?(2315.6-138.08)=1171.94kJ/kg ?qc??c(hc?hc7.小汽轮机冷源损失?qxj
?)?0.0375?(2422.6-138.08)=85.33kJ/kg ?qxj??xj(hxj?hc8.化学补充水冷源损失?qma
?)?0.04655?(84.1-138.08)=-2.5131kJ/kg ?qma??ma(hma?hc9.低压H8疏水冷源损失?qd,8
?)?0.13605?(253-138.08)=15.635kJ/kg ?qd,8??d,8(hd,8?hc20