Qinghai Electric Power Baotou No.2 Thermal Power Plant 5-machine low vacuum transformation Chen Hongyan (Baotou No.2 Thermal Power Plant, Inner Mongolia Baotou 01403(1) changed to low-vacuum heating, and used as a standby unit for low-vacuum heating of 3 or 4 units, greatly enhancing the reliability of heating .
1 Transformation Background Baotou No. 2 Thermal Power Plant is an old plant with an installed capacity of 425 MW. Since it was put into operation in 1958, it has been playing a significant role in the West Inner Mongolia Power Grid and was once the largest power plant in Mengxi. There are 8 8 stoves, of which 1 and 2 are BT*25 90/535. In recent years, with the rise of major power plants, the Baotou No. 2 Thermal Power Plant has not gained much advantage in power supply, but it has great potential for heat supply.
At present, the initial parameters of the world's steam turbines have reached the ultra-high parameters of 600*C); the single shaft power of steam turbines has reached 800MW, and the twin-shaft power has reached 1300MW. The small condensing steam turbines have poor technical and economic indicators, high coal consumption, and low efficiency. Disabled. In accordance with the national energy policy, the realization of cogeneration is an effective measure to save energy and protect the environment. Therefore, for a small condensing power plant, the conversion of a condensing steam turbine to a cogeneration unit is an effective way of seeking development. There are roughly four methods for heating reconstruction: use non-adjusted extraction outlets for extraction; use heating for low vacuum operations to use circulating water for heating; use extraction steam and condensing steam turbines to use extraction heating; change back pressure The steam turbine utilizes exhaust steam for heating.
For the Baotou No. 2 Thermal Power Plant, the No. 1 and No. 2 machines are heat supply units, and the No. 3 and No. 4 machines that are the same as the No. 5 models have undergone low vacuum transformation. The condensing steam turbine operates in a low vacuum and uses circulating water for heating. It was operated in the former Soviet Union in the 1960s. The back pressure can be increased to 0.059-0.078 MPa, and the temperature of the cooling water outlet can reach 80-90*C. Circulating water heating reduces the loss of cold source and significantly increases the economic efficiency of condensing power plants.
With the continuous expansion of the heating area in Baotou No. 2 Thermal Power Plant, the requirements for its heating reliability are getting higher and higher. Therefore, the use of "heating and low-vacuum operation using circulating water for heating" is the best improvement for the 5th machine. method. As a standby unit for low-vacuum heating of 3 and 4 units, it will greatly enhance reliability of heating.
2Improvement measures The specific improvement work is divided into the following three steps (see) (1) Cut the plugs and plugs in front of the 5th and 6th and 6th and 6th and 6th and 5th and 6th and 5th sections of the door. Low-vacuum heating inlet pipe is connected to the heating network back to the mother pipe.
Circulating water liaison tube Low vacuum master tube 5 Machine low vacuum transformation system diagram Note on the map One symbol for dead plug, double lines for the newly added tube, 5 through 6 A changed to hot 31 A, 5 through 6 B to Hot 31B, 1, 2, 3, and 4 are exhaust air doors, and numbers 5 and 6 are water discharge doors.
2. The exhaust air is connected to the highest point of the indoor tube. Hot 32A and hot 32B are newly installed.
Above, obvious economic and social benefits have been achieved. Therefore, this year, the 5th aircraft has also undergone a low vacuum transformation. On the one hand, it can increase profits. On the other hand, it increases the reliability of heating and establishes a good reputation for heating in the power sector.
3 The economic effect of low vacuum operation Generally, the thermal efficiency of the cycle of a condensing power plant can only reach 25%~35%, and more than 60% of the heat is taken away by the cooling water and becomes a loss of cold source. In the low vacuum operation, the condenser is used as a primary heater, the circulating condensation water is used to heat the circulating water, and the circulating water is used in place of the heating network water to heat the exhaust condensation heat, so that the condensing power plant can circulate. Thermal efficiency is greatly improved. At the same time, the low-vacuum operation of circulating water heating can replace many small boilers, and the economic effect is very significant.
The Baotou No.2 Thermal Power Plant has carried out a low-vacuum transformation of the No. 3 and No. 4 machines in recent years. During the heating period, it operates in a low vacuum and the vacuum is reduced to 0.05 MPa. The cooling water outlet water temperature reaches 70° C. One unit can heat 11.96 GJ per hour. Heating area of ​​520,000 m2, power generation coal 4 Conclusions The combined heat and power generation has the combined benefits of energy conservation, environmental improvement, improved heating quality, and increased power supply. The construction of thermal power plants is one of the effective means for the city to improve the quality of the atmospheric environment, and it is a public welfare infrastructure that improves people's quality of life. The transformation of small condensing power plants into heat and power plants is a general trend and an effective way for small-scale condensing power plants to seek development. The above-mentioned method has achieved remarkable economic and social benefits and can be used as a reference.
(2) From the 5th to 5th and 5th to 5th, respectively, the two pipes are added to make the low-heat-supply water outlet pipe and connected to the low-vacuum heating main pipe.
(3) Install exhaust air doors and discharge doors in appropriate positions.
4, put air 3* release air
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