Experimental Study on Regulation Characteristics of Intermediate Pressure Cylinder Regulating Valves of Heat Supply Steam Turbine Under Peak Regulating Mechanism

doi:10.12096/j.2096-4528.pgt.22080

Abstract

Abstract:

In order to meet the requirements of peak regulation, the power load of the steam turbine unit changes greatly. The heating parameters of the steam extraction from the reheated steam pipe also fluctuate greatly. The intermediate pressure (IP) cylinder regulating valves of the steam turbine participate in the regulation to stabilize the heating parameters. For a 300 MW steam turbine adopting such heating mode, the regulation characteristics of the IP cylinder regulating valves was studied experimentally under power load of 250 MW and extraction steam flow of 52.20-53.94 t/h. The results show that, as the opening of regulating valves decreases, the inlet steam flow of the IP cylinder decreases gradually, and reheated steam pressure increases gradually. When the minimum opening of the IP cylinder regulating valves is 24.97%, the inlet steam pressure of the IP cylinder is 3.44 MPa, and pressure of the main extraction steam pipe is 3.13 MPa. The maximum pressure ratio of the high pressure (HP) cylinder is 3.13 and the minimum value is 2.65, decreasing gradually. The exhausting steam temperature of the HP cylinder increases gradually, the highest is 331.76 ℃, the lowest is 312.97 ℃. The efficiency of the IP cylinder is gradually reduced, from 93.37% to 84.78%. The steam enthalpy drops of the HP cylinder and the IP cylinder do not change a lot. However, the first stage extraction steam pressure and the HP cylinder exhausting steam pressure increase. The flow rate of the HP and IP cylinders is reduced, and the work capacity of the HP and IP cylinders is reduced, resulting in the decrease of power load of 9.79 MW. The safety operation index of the unit shaft system remains stable.

Key words: combined heat and power units, heating retrofit, steam turbine, intermediate pressure cylinder regulating valve, regulation characteristics

CLC Number:

TK 263

Zhiyun WANG, Yuzhu ZHAO, Xuedong WANG, Yuanshu ZHANG. Experimental Study on Regulation Characteristics of Intermediate Pressure Cylinder Regulating Valves of Heat Supply Steam Turbine Under Peak Regulating Mechanism[J]. Power Generation Technology, 2022, 43(6): 970-976.

Figures/Tables 8

References 17

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参数	取值	参数	取值
主蒸汽压力/MPa	16.67	主蒸汽温度/℃	538
主蒸汽流量/(t/h)	1 021	再热蒸汽压力/MPa	3.34
再热蒸汽温度/℃	538	再热蒸汽流量/(t/h)	836/839(供热)
额定给水温度/℃	274.30	回热抽汽级数	3高＋4低＋1除氧
额定背压/kPa	4.90	冷却水温度/℃	20
低压末级叶片高度/mm	905	保证热耗率/[kJ/（kW·h）]	7 983.20
采暖抽汽温度/℃	267.50	采暖抽汽压力/MPa	0.50
额定功率/MW	312/305(供热)	额定采暖抽汽量/(t/h)	160

参数	取值	参数	取值
主蒸汽压力/MPa	16.67	主蒸汽温度/℃	538
主蒸汽流量/(t/h)	1 021	再热蒸汽压力/MPa	3.34
再热蒸汽温度/℃	538	再热蒸汽流量/(t/h)	836/839(供热)
额定给水温度/℃	274.30	回热抽汽级数	3高＋4低＋1除氧
额定背压/kPa	4.90	冷却水温度/℃	20
低压末级叶片高度/mm	905	保证热耗率/[kJ/（kW·h）]	7 983.20
采暖抽汽温度/℃	267.50	采暖抽汽压力/MPa	0.50
额定功率/MW	312/305(供热)	额定采暖抽汽量/(t/h)	160

参数	工况1	工况2	工况3	工况4	工况5	参数	工况1	工况2	工况3	工况4	工况5
中压调门开度/%	99.01	48.95	35.33	30.54	24.97	中压缸排汽焓/(kJ/kg)	3 023.47	3 023.51	3 026.12	3 027.83	3 034.82
发电机有功功率/MW	249.43	249.59	247.31	245.69	239.64	中压缸蒸汽焓降/(kJ/kg)	496.56	495.6	499.08	498.44	503.28
主汽流量/(t/h)	782.21	779.33	779.01	779.35	779.04	中压缸效率/%	93.37	92.65	91.36	89.34	84.78
主蒸汽压力/MPa	16.78	16.69	16.74	16.79	16.75	再热抽汽母管压力/MPa	2.27	2.40	2.49	2.64	3.13
主蒸汽温度/℃	533.48	533.10	535.81	532.85	531.76	再热抽汽母管温度/℃	522.52	523.13	525.82	527.37	534.16
主蒸汽焓/(kJ/kg)	3 382.62	3 382.60	3 389.72	3 380.71	3 378.08	再热抽汽母管流量/(t/h)	53.94	52.25	53.14	53.53	52.20
高压缸排汽压力/MPa	3.02	3.07	3.15	3.27	3.65	减温减压器出口供汽压力/MPa	1.11	1.10	1.10	1.10	1.10
高压缸排汽温度/℃	312.97	314.32	317.60	320.29	331.76	减温减压器出口供汽温度/℃	281.22	279.40	279.64	282.80	282.61
高压缸排汽焓/(kJ/kg)	3 024.34	3 026.22	3 032.09	3 035.46	3054.10	减温减压器出口供汽流量/(t/h)	57.67	56.07	57.17	58.08	56.65
高压缸蒸汽焓降/(kJ/kg)	358.28	356.38	357.63	345.25	323.98	小汽机低压调门开度/%	50.61	49.98	50.47	50.97	50.95
高压缸效率/%	76.02	76.31	77.00	76.06	75.80	四抽至小汽机进汽压力/MPa	0.74	0.74	0.736 0	0.73	0.73
高排缸压比	3.13	3.10	3.01	2.93	2.65	四抽至小汽机进汽温度/℃	350.77	350.98	352.05	353.28	356.54
再热器压损/%	8.99	8.68	8.12	7.37	5.59	四抽至小汽机进汽流量/(t/h)	35.61	35.24	35.35	35.62	35.30
中压缸进汽流量/(t/h)	615.20	613.72	611.61	608.70	602.76	调节级压力/MPa	9.470	9.511	9.487	9.565	9.671
中压缸进汽压力/MPa	2.75	2.80	2.89	3.03	3.44	一抽压力/MPa	5.23	5.26	5.30	5.39	5.63
中压缸进汽温度/℃	528.00	527.81	530.94	532.04	539.10	三抽压力/MPa	1.47	1.48	1.47	1.47	1.45
中压缸进汽焓/(kJ/kg)	3 520.03	3 519.11	3 525.20	3 526.27	3 538.10	四抽压力/MPa	0.75	0.75	0.75	0.74	0.74
中压缸排汽压力/MPa	0.47	0.47	0.47	0.47	0.46	凝汽器压力/kPa	5.90	5.93	5.90	5.87	5.86
中压缸排汽温度/℃	280.20	280.22	281.48	282.31	285.56

参数	工况1	工况2	工况3	工况4	工况5	参数	工况1	工况2	工况3	工况4	工况5
中压调门开度/%	99.01	48.95	35.33	30.54	24.97	中压缸排汽焓/(kJ/kg)	3 023.47	3 023.51	3 026.12	3 027.83	3 034.82
发电机有功功率/MW	249.43	249.59	247.31	245.69	239.64	中压缸蒸汽焓降/(kJ/kg)	496.56	495.6	499.08	498.44	503.28
主汽流量/(t/h)	782.21	779.33	779.01	779.35	779.04	中压缸效率/%	93.37	92.65	91.36	89.34	84.78
主蒸汽压力/MPa	16.78	16.69	16.74	16.79	16.75	再热抽汽母管压力/MPa	2.27	2.40	2.49	2.64	3.13
主蒸汽温度/℃	533.48	533.10	535.81	532.85	531.76	再热抽汽母管温度/℃	522.52	523.13	525.82	527.37	534.16
主蒸汽焓/(kJ/kg)	3 382.62	3 382.60	3 389.72	3 380.71	3 378.08	再热抽汽母管流量/(t/h)	53.94	52.25	53.14	53.53	52.20
高压缸排汽压力/MPa	3.02	3.07	3.15	3.27	3.65	减温减压器出口供汽压力/MPa	1.11	1.10	1.10	1.10	1.10
高压缸排汽温度/℃	312.97	314.32	317.60	320.29	331.76	减温减压器出口供汽温度/℃	281.22	279.40	279.64	282.80	282.61
高压缸排汽焓/(kJ/kg)	3 024.34	3 026.22	3 032.09	3 035.46	3054.10	减温减压器出口供汽流量/(t/h)	57.67	56.07	57.17	58.08	56.65
高压缸蒸汽焓降/(kJ/kg)	358.28	356.38	357.63	345.25	323.98	小汽机低压调门开度/%	50.61	49.98	50.47	50.97	50.95
高压缸效率/%	76.02	76.31	77.00	76.06	75.80	四抽至小汽机进汽压力/MPa	0.74	0.74	0.736 0	0.73	0.73
高排缸压比	3.13	3.10	3.01	2.93	2.65	四抽至小汽机进汽温度/℃	350.77	350.98	352.05	353.28	356.54
再热器压损/%	8.99	8.68	8.12	7.37	5.59	四抽至小汽机进汽流量/(t/h)	35.61	35.24	35.35	35.62	35.30
中压缸进汽流量/(t/h)	615.20	613.72	611.61	608.70	602.76	调节级压力/MPa	9.470	9.511	9.487	9.565	9.671
中压缸进汽压力/MPa	2.75	2.80	2.89	3.03	3.44	一抽压力/MPa	5.23	5.26	5.30	5.39	5.63
中压缸进汽温度/℃	528.00	527.81	530.94	532.04	539.10	三抽压力/MPa	1.47	1.48	1.47	1.47	1.45
中压缸进汽焓/(kJ/kg)	3 520.03	3 519.11	3 525.20	3 526.27	3 538.10	四抽压力/MPa	0.75	0.75	0.75	0.74	0.74
中压缸排汽压力/MPa	0.47	0.47	0.47	0.47	0.46	凝汽器压力/kPa	5.90	5.93	5.90	5.87	5.86
中压缸排汽温度/℃	280.20	280.22	281.48	282.31	285.56

测点	测试数据			DCS显示振幅/μm
测点	通频振幅/μm	一倍频振幅/μm	一倍频相位/(°)	DCS显示振幅/μm
1X	95	75	39	96
1Y	49	33	92	51
2X	121	118	236	122
2Y	79	73	326	80
3X	37	32	215	37
3Y	45	40	304	44
4X	26	12	20	24
4Y	38	21	200	36
5X	79	68	218	77
5Y	43	32	321	41
6X	70	56	283	71
6Y	70	50	14	69
7X	26	11	138	27
7Y	9	5	181	10