CN104533545A - Novel air cooling system - Google Patents

Abstract

The invention discloses a novel air cooling system which comprises a turbine, an air cooling tower and a condensation tank. An air cooling condenser is arranged under the air cooling tower, and exhaust steam of the turbine passes through a steam exhaust pipeline into the air cooling condenser and performs heat transfer with cooling air directly. The air cooling condenser is communicated with the condensation tank through a lower water header, and cooling condensed condensated water is collected into the condensation tank through the lower water header. A condensation pump is arranged at the outlet of the condensation tank. Pressure boost is performed on the condensated water through the condensation pump, and the condensated water is sent to a sealing heater and flows into a heat regenerative system. The novel air cooling system has the advantages of a direct air cooling system and a surface condensation type indirect cooling system, and abandons the defects of the direct air cooling system and the surface condensation type indirect cooling system effectively. The novel air cooling system has the advantages that the power consumption is nearly zero, the heat exchange efficiency is high, the annual operation vacuum is high, and the ability of environment resistance is strong. The problems that a current air cooling machine unit needs to face are solved effectively, and the economy in the machine unit operation is increased. The novel air cooling system can be applied to the aspects such as heat energy power engineering, a thermal power plant, and the aspect that the safety, economy and energy saving and cost reducing of the air cooling machine unit are improved.

Description

A new type of air cooling system

technical field

The invention belongs to the fields of heat energy exchange and aerodynamics, and relates to a cold end system of a power station, in particular to a novel air cooling system.

Background technique

As an effective water-saving thermal power generation technology, the air-cooling technology of power plants is widely used in the power industry in areas where water resources are scarce. Looking forward to the future, the prospect of air-cooling technology for power plants is still promising. It can not only be used in water-scarce areas, but also has very high practical applications in terms of reducing water resource consumption and promoting sustainable use of water resources even in areas with abundant water resources. value.

There are three main types of air cooling systems currently used in power plants, namely direct air cooling systems, indirect air cooling systems with hybrid condensers (Heller type) and indirect air cooling systems with surface condensers (Harmon type).

In China, the direct air cooling system is the most widely used, followed by the surface condensing intercooling system, and finally the condensing intercooling system. The former two account for more than 98% of the installed capacity of air coolers. Decades of operating experience show that the water-saving advantages of the air-cooling system are quite obvious, but its disadvantages are also quite prominent: 1) In terms of direct air-cooling technology, there are high plant power consumption, low vacuum unit output during high temperature periods in summer, and sensitivity to environmental influences. 2) In terms of the surface condensing intercooling system, there are disadvantages such as high plant power consumption and low efficiency of two heat exchanges.

The direct air cooling system and the surface condensing intercooling system are comprehensively compared in terms of water saving effect, plant power consumption, environmental sensitivity, heat exchange efficiency, and annual operating economy, as follows:

1) Water-saving effect: the two are equivalent.

2) In terms of power consumption: the direct air cooling system uses an axial flow variable frequency fan. Although the frequency is adjusted according to the load of the unit and the inlet air temperature, the power consumption is still relatively large, and the power consumption rate is about 1% under full load; the table The circulating cooling water of the condensing intercooling system is supplied by two or three circulating water pumps. Although the circulating water pumps are optimized according to the load of the unit and the ambient temperature, the power consumption is still relatively large, which is basically the same as that of direct air cooling.

3) Environmental sensitivity: the direct air cooling system is more sensitive to the influence of ambient wind, and the operating back pressure of the unit varies greatly; the surface condensing intercooling system has a slower influence on the ambient wind, and the operating back pressure of the unit varies relatively small .

4) Heat exchange efficiency: The exhaust steam and cooling air in the direct air cooling system belong to one-time heat exchange, and the heat exchange efficiency is high, so the heat dissipation area is small; Transferred to the cooling air, the heat transfer efficiency is low, so the heat dissipation area is large.

5) Annual operation economy: The annual operating back pressure of the surface condensing intercooling system unit is lower than that of the direct air cooling system unit.

In summary, the direct air cooling system and the surface condensing intercooling system have obvious water saving effects, but the power consumption is also obvious. In addition, the direct air cooling system has high heat transfer efficiency, while the surface condensing intercooling system has poor environmental sensitivity and high annual operation economy. Under the national policy of energy conservation and emission reduction, and building a conservation-oriented society, how to effectively combine the advantages of the above two air-cooling forms, while discarding their disadvantages, and improving the advantages of air-cooling technology is becoming more and more important.

Contents of the invention

The purpose of the present invention is to solve the above problems and propose a new type of air cooling system, which takes into account the advantages of the direct air cooling system and the surface condensing intercooling system, and effectively abandons their respective shortcomings. The invention has the advantages of almost no power consumption, high heat exchange efficiency, high annual operating vacuum, and strong environmental resistance ability, effectively solves the problems faced by the current air-cooling unit, and improves the operating economy of the unit. The invention can be applied to thermal power engineering, thermal power plants, air-cooling units to improve safety, economy, energy saving and consumption reduction, and the like.

In order to achieve the above object, the technical solution adopted in the present invention is:

A new type of air-cooling system, including a steam turbine, an air-cooling tower, and a condensed water tank; an air-cooling condenser is vertically arranged around the lower part of the air-cooling tower, and the exhaust steam of the steam turbine is introduced into the air-cooling condenser through the exhaust pipe for direct heat exchange with the cooling air; The air-cooled condenser is connected with the condensate water tank through the water header, and the condensed water is collected into the condensate water tank through the water header; the outlet of the condensate water tank is equipped with a condensate water pump, and the condensate water is boosted by the condensate water pump. Enter the heat recovery system after the shaft seal heater.

The air cooling tower is a natural ventilation cooling tower, which is installed outside the factory building, and its cooling air is generated by the natural suction of the natural ventilation cooling tower.

The cooling tube bundles in the air-cooled condenser are steel tubes with aluminum fins, hot-dip galvanized.

The air-cooled condenser is a plurality of cooling units evenly arranged along the circumferential direction of the air-cooling tower, and the condensed water outlets of these cooling units are all connected to the condensed water tank through the water header.

The end of the exhaust pipe is provided with a steam distribution pipe connected to the air inlets of several cooling units, which distributes the exhaust steam of the steam turbine in the exhaust pipe to each cooling unit, and is cooled by the cooling air flowing through the air-cooled condenser.

The steam distribution pipe includes an annular steam distribution main pipe communicated with the exhaust pipe, and a branch pipe for leading the exhaust steam of the steam turbine into the corresponding cooling unit is provided at a corresponding position inside the annular steam distribution main pipe.

The air-cooled condenser is also provided with a vacuum system for extracting non-condensable gas from the air-cooled condenser.

The vacuum system includes a vacuum pipeline and a water ring vacuum pump. One end of the vacuum pipeline communicates with the air-cooled condenser, and the other end is connected to the water ring vacuum pump.

Each cooling unit of the air-cooled condenser includes a downstream part for guiding condensed water and a countercurrent part for cooperating with the vacuum system to draw away non-condensable gas, and the vacuum pipe is connected with each cooling unit The reverse flow part is connected.

Compared with the prior art, the present invention has the following beneficial effects:

The difference between the present invention and the traditional air-cooling unit (whether it is direct air-cooling unit or indirect air-cooling unit) is that there is neither a certain number of variable frequency axial flow fans nor countless circulating water pumps; the cold end system has no power consumption equipment, so it can effectively save Plant electricity; equipment such as condensate tank and condensate pump are installed near the lower part of the air-cooling tower, so the anti-cavitation performance of the condensate pump is required to be high; since the air-cooling tower is a certain distance from the main engine building, auxiliary equipment such as vacuum pumps can be installed near the tower . The air-cooled condenser belongs to primary heat exchange, with high heat transfer coefficient; poor environmental sensitivity, and low back pressure during operation throughout the year. The present invention has neither a large number of axial flow fans in the direct air cooling system nor several circulating water pumps in the surface condensing intercooling system, effectively saves plant power consumption, and improves the operating economy of the air-cooling generating set as a whole.

Description of drawings

Fig. 1 is a schematic flow sheet of the present invention;

Figure 2 is a schematic diagram of the steam distribution system of the present invention.

Among them, 1 is steam turbine; 2 is exhaust device; 3 is exhaust pipe and steam distribution pipe; 4 is natural ventilation cooling tower; 5 is air-cooled condenser; 6 is water header; 7 is vacuum pipe; 8 is Water ring vacuum pump; 9 is condensed water tank; 10 is condensed water pump; 11 is shaft seal heater; 12 is annular steam distribution main pipe; 13 is branch pipe.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail:

Referring to Fig. 1 and Fig. 2, the exhaust steam of the steam turbine of the present invention is introduced into the air-cooled condenser arranged on the lower periphery of the natural draft cooling tower through the exhaust pipe and the steam distribution pipe, and directly exchanges heat with the cooling air, and the condensed water after condensation passes through The water header is collected into the condensate tank, and then enters the heat recovery system after being boosted by the condensate pump. The air-cooling tower is a natural ventilation cooling tower, which is installed at a certain position outside the factory building. The cooling air is generated by the natural suction of the air-cooling tower, and the air-cooling condenser is vertically arranged around the lower part of the air-cooling tower. The air-cooled condenser is evenly divided into several cooling units along the circumferential direction of the air-cooling tower. The schematic diagram (top view) of the steam distribution system is shown in Figure 2. The steam is distributed into the cooling unit by the steam distribution pipe, cooled by the cooling air flowing through the air-cooled condenser, and the condensed water is collected into the water header. Each cooling unit of the air-cooled condenser is provided with a forward flow part and a reverse flow part. The cooling tube bundle is steel tube with aluminum fins, hot-dip galvanized. The present invention is also provided with a vacuum system to extract the non-condensable gas in the air-cooled condenser. In addition, the condensed water tank of the present invention is arranged at the lower part of the air-cooled condenser of the air-cooling tower, and the condensed water pump is arranged at the lower part near the condensed water tank.

Application effect:

The biggest feature of this technology is that it saves not only the air-cooling fan of the direct air-cooling system, but also the circulating water pump of the surface condensing intercooling system, saving power consumption of the plant, and the power consumption of the plant is reduced by about 1%. The 600MW air-cooling unit is the main For example, the coal consumption rate of power supply is reduced by about 4g/(kW·h), which is obviously economical. In addition, the reduction of coal consumption rate means that the emission of nitrogen oxides and other pollutants under the same load has decreased, and the environmental benefits are remarkable.

The above content is only to illustrate the technical ideas of the present invention, and cannot limit the protection scope of the present invention. Any changes made on the basis of the technical solutions according to the technical ideas proposed in the present invention shall fall within the scope of the claims of the present invention. within the scope of protection.

Claims (9)

1. a novel air cooling system, is characterized in that: comprise steam turbine (1), air cooling tower (4) and condensate water tank (9); The lower periphery of air cooling tower (4) has been arranged vertically air cooling condenser (5), and turbine discharge is introduced in air cooling condenser (5) through blow-off line (3) and carried out direct heat transfer with cooling-air; Air cooling condenser (5) is connected with condensate water tank (9) by lower water manifold (6), and condensed water of condensation is collected in condensate water tank (9) through lower water manifold (6); The outlet port of condensate water tank (9) is provided with condensate pump (10), and water of condensation enters heat regenerative system send into gland heater (11) after condensate pump (10) boosting after.

2. novel air cooling system according to claim 1, is characterized in that: described air cooling tower (4) is natural draft cooling tower, is arranged at factory building outside, and its cooling-air is produced by natural draft cooling tower nature suction force.

3. novel air cooling system according to claim 1, is characterized in that: the cooling tube bundle in described air cooling condenser (5) is steel pipe aluminum fin-stock, hot galvanizing.

4. novel air cooling system according to claim 1, it is characterized in that: described air cooling condenser (5) is several cooling units be evenly arranged along air cooling tower (4) circumferencial direction, and the outlet of the water of condensation of these cooling units is all connected with condensate water tank (9) by lower water manifold (6).

5. novel air cooling system according to claim 4, it is characterized in that: the end of described blow-off line (3) arranges the steam-distributing pipe be connected with some cooling unit suction ports, turbine discharge in blow-off line (3) is dispensed to each cooling unit, and is cooled by the cooling-air flowing through air cooling condenser (5).

6. novel air cooling system according to claim 5, it is characterized in that: described steam-distributing pipe comprises the annular steam be connected with blow-off line (3) and distributes female pipe (12), the relevant position, inner side that annular steam distributes female pipe offers for turbine discharge being distributed the arm (13) importing corresponding cooling unit.

7. novel air cooling system according to claim 1, is characterized in that: described air cooling condenser (5) is also provided with the pumped vacuum systems for extracting incondensable gas in air cooling condenser.

8. novel air cooling system according to claim 7, it is characterized in that: described pumped vacuum systems comprises vacuum lead (7) and water ring vaccum pump (8), one end of vacuum lead (7) is connected with air cooling condenser (5), and the other end is connected on water ring vaccum pump (8).

9. the novel air cooling system according to claim 7 or 8, it is characterized in that: each cooling unit of described air cooling condenser (5) all comprises for the following current part of the water of condensation that leads with for coordinating the reflux fraction taken away by incondensable gas with pumped vacuum systems, and vacuum lead (7) is connected with the reflux fraction on each cooling unit.