?d,8=?d,7+?8=0.10319+0.02998=0.13307
4、汽轮机凝气系数的计算及检验 (1)由凝汽器的质量平衡给计算ac
?c??c,5??d,8??xj???sg??ma
=0.76667-0.13307-0.03751-0.003924-0.03786 =0.55451
(2)由汽轮机汽侧平衡校验ac
'H4抽汽口抽汽系数和?4 '?4=?4+?xj+?nf+?pl
=0.04252+0.03751+0.03235+0.01082 =0.12300
各加热器抽汽系数和??j
??j'=?1+?2+?3+?4+?5+?6+?7+?8
=0.07143+0.07218+0.03749+0.12320+0.02772+0.02838+0.04709+0.02998 =0.43718 轴封漏汽系数和??sg,k
??sg,k=?sg,2+?sg,4+?sg,5+?sg,6+?sg,7+?sg,8+?sg,9+?sg,10
=0.0001913+0.001430+0.001032+0.001591+0.001265+0.0006731+ 0.0007626+0.001369 =0.008314 凝汽系数?c:
?c=1-??j-??sg,k=1-0.43718-0.008314=0.55451
该值与由凝汽器质量平衡计算得到的ac相等,所以凝汽系数计算正确。 3.2.3 汽轮机汽耗D0的计算及流量校核
(1)估算汽轮机纯凝气运行时的汽耗Dc,0,锅炉热负荷Qb及煤耗量
Bcp?ic?h0?hc?qrq?3402.9?2325.9?(3538.29?3029.25)?1585.79KJ/Kg Dc,0?3600Pe?3600?300MW?1000?692080.3kg/h
1585.79kJ/kg?0.994?0.99?ic?m?g13
取由于回热而增大的汽耗子系数:??1.26,则汽轮机汽耗: D0??Dc,0?1.26?692080.3?872021.2kg/h (3)汽轮机??ijHij的计算如下表3所示:
表3:??ijHij计算
气 缸 高 压 缸 气态 线段 0-1 '? Hij ?ijHijKJ/Kg 327.57 ?0?1??0??sg.1?1?0.01?0.99 H0?1?h0?h1?3402.9?3072.02 ?330.88H1?2?h1?h2?3072.02?3029.51 ?42.51H2?3?h1?h2?3538.29?3320.72 ?217.57 1-2 ?1?2??0?1??1?0.99?0.0302 ?0.9598'?2?3??rh??1?2??2?0.9598?0.0825?0.877340.80 中 压 缸 2-3 190.22 ?rh????sg,2?0.8773?0.003?0.8743'?3?4??rh??3'rh 3-4 H3?4?h3?h4?3320.72?3121.64 ?199.08H4?5?h4?h5165.67 4-5 ?0.8743?0.0421 ?0.8322?4?5??3?4??4??sg,3??L91.07 ?0.8322?0.07?0.0014?0.01?3121.64?3000.34 ?121.3?0.7503 5-6 ?5?6??4?5??5?0.7508?0.0348 ?0.716?6?7??5?6??6?0.716?0.0337 ?0.6823?7?8??6?7??7?0.6823?0.028 ?0.6543H5?6?h5?h6?3000.34?2851.74 ?148.6H6?7?h6?h7?2851.74?2697.62 ?154.12 106.40 低压缸 6-7 105.16 7-8 0.66~0.83MPa94.69 14
8-c ?8?c??7?8??8H8?c?h8?hc?2552.9?2325.9 ?227140.31 整机 ?0.6543?0.0362 ?0.6181??ijHij?1261.89KJ/Kg 由功率平衡式求汽耗D0: 误差:
D0?D'0|869722.4?872021.2|?D??100%??100%?0.26%?0.5%,是允许的。
D0872021.2气耗率:
D869722.4?2.9Kg/(KW.h)。 d0?0?Pe300000以D0?869722.4kg/h为基准,计算各项汽水流量如下表4所示: 表4: 各项汽水流量
项目 第一级抽汽D1?0.0302D0 第二级抽汽D2?0.0825D0 第三级抽汽D3?0.0421D0 H4汽耗 Dr4?0.0234D0 kg/h 26265.6 71752.1 36615.3 20525.4 项目 第七级抽汽D7?0.028D0 第八级抽汽D8?0.0362D0 凝汽量 Dc?0.6181D0 锅炉蒸发量 Db?D0 给水流量 Dfw?1.005D0 再热蒸汽流量 Drh?0.8773D0 补充水量 Dmm?0.0015D0 kg/h 24352.2 31484.0 537575.4 869722.4 874071 763007.5 13045.8 小汽轮机汽耗 DtDT?0.0464D0 40335.1 第五级抽汽D5?0.0348D0 第六级抽汽D6?0.0337D0 30266.3 29309.6 3.2.4 热经济性指标计算
(1) 汽轮机组热耗Q0、汽轮机比热耗q0、汽轮机绝对内效率?i
mm Q0?D0(h0?hfw)?Drhqrh?Dmm(hfw?hw)
=869722.4(3402.9-1096.15)+763007.5(3538.29-3029.5)—13045.8(1096.15—167.44)
=2382326967KJ/h=2382GJ/h q0?h0?hfw??mm(hfw?hmm)
=3402.9-1096.15+0.8773(3538.29-3029.5)-0.015(1096.15-167.44)
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=2739.2KJ/Kg
w1261.89?0.46067 ?t?t?q02739.2(2)汽动给水泵功率:
DfwVfw(Pfp?Pd)874071?1.1?(21.2?0.89)DT Pe(fp)???6381.6kw
3600??fp3600?0.85(3)汽轮机产电功率Q0e、热耗率qe、热效率?ee、汽轮发电机组绝对电效率?e
e Q0?Q0?2382.32GJ/h
eQ02382.32?106 q???7775.66kJ/(kW?h) DT3Pe?Pe300?10?6381.636003600?0.46298 ?ee?e?q7775.66e3600Pe3600?300?103 ?e???0.45333
Q02382.32?106(4)锅炉热负荷Qb
Qb?Dbhb?Dfwhfw?Drhqrh(b)
=869722.4×3411.17-874071×1096.15+763007.5×(3548.9-3018.5) =2413.357GJ/h (5) 管道效率?p ?p?Q02382.32??98.71% Qb2413.36n(6)全厂(单元)热耗Qcp、热耗率qcp、净热效率?cp、全厂(单元)毛效率?cp、n净效率?cp
Qcp?Qb?GJ/h ?b全厂(单元)毛效率:?cp??e?p?b?
qcp?36003600??kJ/(kW?h)?cp
n?cp??cp(1??)
ss (7)全厂煤耗Bscp、全厂发电标准煤耗b,全厂供电标准煤耗率bn
全厂标准煤耗量:
B?scpQcpqs?kg标煤/h
(注:取中国标准煤发热量qs=29270kJ/kg)
全厂原煤耗量:Bcp?Qcpq1?kg/h
(注:取燃煤低位发热量q1=15660kJ/kg)
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bs?全厂发电标煤耗率:
n?净供电煤耗率:bcp3600?g标煤/(kw?h)?cp?29270
0.123?g标煤/(kw?h) n?cp 3.2.5 110%工况经济指标
机组的最大工况即110%工况,此时机组的进气压力和温度都不变,只是进气量有所增加;因此汽轮机每级后蒸汽参数也不变,抽汽参数也与额定工况相同。 (1)功率平衡式求汽耗率D'0
3600Pe'D??kg/h??ijHij?m?g
'0汽耗率:
D'0'd0?'??kg/(KW?h)
Pe
(2)汽轮机组热耗Q'0、汽耗机比热耗q'0,汽轮机绝对内效率?i' Q'0?Q'0(h0?hfw)?D'rhqrh?D'mm(hfw?hmmw)
' q0?h0?hfw??rhqrh??mm?hfw?hmm?
?i?wi1261.89??0.46067 q02739.2(3)汽动给水泵功率:
Dfw'Vfw?Pfp?Pd?961478.2?1.1??21.2?0.89?DT Pe?fp?'???7019.8kw
3600??fp3600?0.85e'(4)汽轮机产电功率Q0、热耗率qe'、热效率?ee'、汽轮机发电机组绝对电效率?e'
e Q0'?Q0'?2620.6GJ/h
eQ0'2620.6?106 qe'???7775.8kJ/?kW?h? DT3Pe?Pe?fp?'330?10?7019.836003600?0.46297 ?ee'?e?q'7775.83600Pe'3600?330?103 ?e'???0.45333 6Q0'2620.6?10(5)锅炉热负荷Qb'
Qb'?Db'hb?Dfw'hfw?Drh'qrh?b??956694.7?3411.17?961478.2?1096.15?839308.3??3548.9?3018.5? ?2654.7GJ/h(6)全厂(单元)热耗Qcp'
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