CN105298565A - Variable working condition active-control light-coal complementation indirect air-cooling generation system and method - Google Patents

Abstract

The invention discloses a light-coal complementary indirect air-cooled power generation system and method actively regulated by variable working conditions. The system includes boilers, steam turbines, generators, high-pressure and low-pressure feed water heaters, deaerators, steam extraction branch control valves, Absorption refrigerator, air-cooled condenser, feed water branch control valve, mirror field heat exchanger and compound parabolic concentrator. During the daytime in summer, the ambient temperature rises and the back pressure of the steam turbine rises. The low-pressure extraction steam of the steam turbine is used to drive the absorption refrigerator, and cools the air at the inlet of the air-cooled condenser, so that the back pressure of the steam turbine is close to the design value. The concentrator is used to replace the original low-pressure extraction The steam heats the feed water; during the daytime in winter, when the ambient temperature drops, the back pressure of the steam turbine can maintain the design value, the low-pressure extraction steam of the steam turbine continues to expand and work, and the concentrator is used to replace the original low-pressure extraction steam to heat the feed water. The invention solves the problem that the operating efficiency of the traditional air-cooling unit decreases under variable working conditions in summer, improves the annual average power generation efficiency of the unit, and realizes the high-efficiency utilization of low-temperature solar energy.

Description

A light-coal complementary indirect air-cooled power generation system and method for active regulation under variable working conditions

technical field

The invention relates to the technical field of solar energy and fossil energy complementary power generation and indirect air cooling, and in particular to a light-coal complementary indirect air-cooling power generation system and method that are actively regulated under variable working conditions.

Background technique

As of the end of 2009, a total of 35.4GW direct air-cooled thermal power units were put into operation in my country, with an installed capacity of 5.4% of the total installed capacity of thermal power. Direct air-cooled units have the advantages of water saving, good antifreeze performance, small footprint, and low investment costs. But at the same time, the direct air-cooling unit is significantly affected by the environment, and the ambient temperature will have an adverse impact on its economic operation. During the hot summer period, the unit’s operating back pressure is high, rising from the design back pressure of 10-19kPa to 30-40kPa, and the unit is forced to drop The load operation has seriously affected the economic operation of the unit, and the annual average power generation efficiency of the unit will drop significantly. For this reason, some power stations frequently clean the air-cooling units with high standards in summer, or install water spray to cool down, but this runs counter to the water-saving goal of direct air-cooling, and has little effect.

It is worth noting that hot weather in summer is usually accompanied by high solar radiation intensity, which provides a new idea for improving the operating performance of direct air-cooled units in summer under variable conditions. The utility model patent with the application number 201420508838.7 proposes an air-cooling unit for solar absorption refrigeration. The absorption refrigeration is driven by a solar collector, and heat is exchanged in the air-cooling unit to reduce the inlet air temperature of the air-cooler and strengthen the cooling of the air-cooler. purpose of the effect. However, the above schemes are mainly aimed at the hot summer. When the ambient temperature drops in winter and the air-cooled unit can achieve the rated operating conditions, the solar mirror field will be idle for a long time, resulting in waste of fixed investment, and it is difficult to improve the economy of the entire system.

Therefore, how to carry out active regulation of the whole system, ensure the stable power generation of thermal power units under variable working conditions, realize the annual power generation efficiency of the unit close to the rated working conditions, and make full and effective use of solar resources, has become a solution to direct air-cooled variable working conditions using solar energy. The key technical issues of the puzzle.

Contents of the invention

(1) Technical problems to be solved

In view of this, the main purpose of the present invention is to provide a solar-coal complementary indirect air-cooled power generation system and method that is actively regulated under variable working conditions, and couple key processes such as the power island, heat recovery subsystem, and absorption refrigeration unit of the system with each other, According to different environmental conditions, the active control of the indirect cooling of the solar-coal complementary system is realized through the active switching of the low-pressure steam extraction of the steam turbine to heat the feed water, drive the absorption refrigeration, and expand the work, so that the summer power generation efficiency of the thermal power station is still close to Design working conditions, and solar energy resources can be effectively used in winter to improve the technical economy of the entire system.

(2) Technical solution

In order to achieve the above purpose, the present invention provides a light-coal complementary indirect air-cooled power generation system that is actively regulated by variable working conditions. The system includes a boiler 1, a steam turbine high-pressure cylinder 2, a steam turbine medium-pressure cylinder 3, a steam turbine low-pressure cylinder 4, and a generator 5 , high-pressure feed water heater 6, high-pressure feed water pump 7, deaerator 8, low-pressure feed water heater 9, low-pressure feed water pump 10, steam extraction flow control valve 11, absorption refrigerator 12, air-cooled condenser 13, feed water flow path Control valve 14, mirror field heat exchanger 15 and compound parabolic concentrator 16, wherein:

Boiler 1, steam turbine high pressure cylinder 2, steam turbine medium pressure cylinder 3, steam turbine low pressure cylinder 4, generator 5, high pressure feed water heater 6, high pressure feed water pump 7, deaerator 8, low pressure feed water heater 9, low pressure feed water pump 10 and The air-cooled condenser 13 constitutes a thermal cycle circuit; the absorption refrigerator 12 and the air-cooled condenser 13 constitute a branch of the absorption refrigerator, the mirror field heat exchanger 15 and the compound parabolic concentrator 16 constitute a mirror field heat exchanger branch, and the steam turbine The low-pressure cylinder 4 and the low-pressure feedwater heater 9 form a steam extraction and heating feedwater branch;

Boiler 1 generates main steam, which expands and works through steam turbine high-pressure cylinder 2, steam turbine medium-pressure cylinder 3, and steam turbine low-pressure cylinder 4 in turn, and drives generator 5 to output electric power to the outside; exhaust steam enters air-cooled condenser 13 and is cooled into condensed water, which is supplied by low pressure to The water pump 10 pressurizes, enters the low-pressure feedwater heater 9 for heating, then enters the deaerator 8, and then further pressurizes through the high-pressure feedwater pump 7, enters the high-pressure feedwater heater 6, and after heating to the boiler inlet water temperature requirement, enters the boiler to complete the heat cycle;

During the daytime in summer, when the ambient temperature rises, causing the back pressure of the steam turbine to rise, the extraction flow control valve 11 opens the branch circuit of the absorption refrigerator, and the low-pressure extraction steam of the steam turbine is used to drive the absorption refrigerator, and the inlet air of the air-cooled condenser 13 Cooling is carried out so that the back pressure of the steam turbine is close to the design value; at the same time, the feedwater flow control valve 14 opens the mirror field heat exchanger branch, and the compound parabolic concentrator 16 is used to replace the original low-pressure steam extraction to heat the low-pressure feedwater;

During the daytime in winter, when the ambient temperature drops and the steam turbine can maintain the back pressure at the design value, the extraction flow path control valve 11 closes the branch circuit of the absorption refrigerator, and the low-pressure extraction steam of the steam turbine can continue to expand and perform work in the low-pressure cylinder 4 of the steam turbine; at the same time , the feedwater flow path control valve 14 opens the mirror field heat exchanger branch, enables the composite parabolic concentrator 16, and replaces the original low-pressure steam extraction to heat the low-pressure feedwater;

In summer and winter nights, when the ambient temperature drops and the back pressure of the steam turbine can be maintained at the design value, the steam extraction flow control valve 11 closes the branch of the absorption refrigerator, opens the steam extraction to heat the water supply branch, and the low-pressure steam extraction of the steam turbine enters the minimum pressure. The low-pressure feedwater heater 9 restores the function of heating the feedwater; at the same time, the feedwater flow control valve 14 closes the mirror field heat exchanger branch, and the compound parabolic concentrator 16 closes.

In the above scheme, the temperature of the driving heat source required by the absorption refrigerator 12 is close to the low-pressure steam extraction temperature of the steam turbine, and the heat collection temperature of the compound parabolic concentrator 16 is close to the heating temperature of the low-pressure feedwater, so that the system realizes indirect air cooling and improves the cycle efficiency of the steam turbine. At the same time, it ensures the minimum irreversible loss in the new process; and because there is a positive correlation between the intensity of solar radiation and the ambient temperature, under different environmental conditions, low-pressure steam extraction can be used to heat low-pressure feed water, drive absorption refrigeration, and expand in the low-pressure cylinder of the steam turbine. The active switching between the three functions of work realizes the active regulation of the indirect refrigeration of the solar-coal complementary system.

In the above scheme, the extraction flow path control valve 11 opens the branch circuit of the absorption refrigerator during the daytime in summer, and its flow control depends on the increase of the ambient temperature, resulting in an increase in the temperature of the inlet air of the condenser, so as to meet the extraction cooling capacity as much as possible. The air temperature can be cooled to the design value.

In the above scheme, the steam extraction flow path control valve 11 closes the branch circuit of the absorption refrigerator during the daytime in winter, and the extraction steam expands in the low-pressure cylinder of the steam turbine to perform work; when the heat collected by the compound parabolic concentrator 16 cannot fully meet the heating demand of the low-pressure feed water When , part of the extracted steam still enters the low-pressure feedwater heater, and its flow control depends on the solar radiation, so that the heat release is enough to heat the remaining feedwater to the design temperature.

In the above scheme, the feed water flow path control valve 14 opens the branch of the mirror field heat exchanger during the daytime in summer and winter, and its flow control depends on the solar irradiation, so that the heat collected by the compound parabolic concentrator 16 will enter the mirror field for exchange. The feed water in the heater branch is heated to the design temperature.

In the above solution, the mirror field heat exchanger 15 is connected in parallel with the low-pressure feedwater heater 9, and operates in series with the rest of the feedwater heaters in the heat recovery system of the power station.

In the above solution, the low-pressure extraction steam driven by the absorption refrigerating machine 12, after releasing heat and condensing in the refrigerating machine, is collected with other condensed water at the outlet of the air-cooled condenser 13, and participates in the thermodynamic cycle of the unit again.

In order to achieve the above purpose, the present invention also provides a light-coal complementary indirect air-cooled power generation method that is actively regulated under variable working conditions. The method includes:

Boiler 1 generates main steam, which expands and works through steam turbine high-pressure cylinder 2, steam turbine medium-pressure cylinder 3, and steam turbine low-pressure cylinder 4 in turn, and drives generator 5 to output electric power to the outside; exhaust steam enters air-cooled condenser 13 and is cooled into condensed water, which is supplied by low pressure to The water pump 10 pressurizes, enters the low-pressure feedwater heater 9 for heating, then enters the deaerator 8, and then further pressurizes through the high-pressure feedwater pump 7, enters the high-pressure feedwater heater 6, and after heating to the boiler inlet water temperature requirement, enters the boiler to complete the heat cycle;

During the daytime in summer, when the ambient temperature rises and the back pressure of the steam turbine rises, the extraction flow control valve opens the branch circuit of the absorption refrigerator, and the low-pressure extraction steam of the steam turbine is used to drive the absorption refrigerator to cool the air at the inlet of the air-cooled condenser , so that the back pressure of the steam turbine is close to the design value; at the same time, the feedwater flow control valve opens the mirror field heat exchanger branch, and the compound parabolic concentrator is used to replace the original low-pressure steam extraction to heat the low-pressure feedwater;

During the winter day, when the ambient temperature drops and the steam turbine can maintain the back pressure at the design value, the extraction flow control valve closes the branch circuit of the absorption refrigerator, and the low-pressure extraction steam of the steam turbine can continue to expand and work in the low-pressure cylinder of the steam turbine; at the same time, the The water flow control valve opens the mirror field heat exchanger branch, and enables the compound parabolic concentrator to replace the original low-pressure steam extraction to heat the low-pressure feed water;

In summer and winter nights, when the ambient temperature drops and the back pressure of the steam turbine can be maintained at the design value, the steam extraction flow control valve closes the branch of the absorption refrigerator, opens the steam extraction heating water supply branch, and the low-pressure steam extraction of the steam turbine enters the lowest pressure The low-pressure feed water heater restores the function of heating the feed water; at the same time, the feed water flow control valve closes the branch of the mirror field heat exchanger, and the mirror field of the compound parabolic concentrator is closed.

In the above scheme, the extraction flow path control valve 11 opens the branch circuit of the absorption refrigerator during the daytime in summer, and its flow control depends on the increase of the ambient temperature, which leads to the increase of the temperature of the inlet air of the condenser, that is, to meet the requirements of extraction refrigeration as much as possible. The amount can cool the air temperature to the design value.

In the above scheme, the steam extraction flow path control valve 11 closes the branch circuit of the absorption refrigerator during the daytime in winter, and the steam extraction can be expanded in the low-pressure cylinder of the steam turbine to perform work; when the heat collected by the compound parabolic concentrator 16 cannot fully meet the heating demand of the low-pressure feed water , part of the extracted steam still enters the low-pressure feedwater heater, and its flow control depends on the solar radiation, so that the heat release is enough to heat the remaining feedwater to the design temperature.

In the above scheme, the feed water flow path control valve 14 opens the branch of the mirror field heat exchanger during the daytime in summer and winter, and its flow control depends on the solar irradiation, so that the heat collected by the compound parabolic concentrator 16 will enter the mirror field for exchange. The feed water in the heater branch is heated to the design temperature.

In the above scheme, the light-coal complementary indirect air-cooled power generation system actively regulated under variable working conditions according to claim 1 is characterized in that the mirror field heat exchanger 15 is connected in parallel with the low-pressure feed water heater 9, and is connected with the power station return The remaining feedwater heaters in the thermal system operate in series.

In the above solution, the low-pressure extraction steam driven by the absorption refrigerating machine 12, after releasing heat and condensing in the refrigerating machine, is collected with other condensed water at the outlet of the air-cooled condenser 13, and participates in the thermodynamic cycle of the unit again.

(3) Beneficial effects

As can be seen from the foregoing technical solutions, the present invention has the following beneficial effects:

1. Using the present invention, during the daytime in summer, the absorption refrigerator is driven by low-pressure steam extraction to cool down the air-cooling unit, so that the stable and efficient operation of the direct air-cooling unit in summer can be realized, and the power generation efficiency is close to the design level;

2. Using the present invention, during the daytime in winter, the solar heat collecting mirror field replaces the low-pressure steam extraction to heat the low-pressure feed water, and the low-pressure extraction steam can continue to expand and do work in the low-pressure cylinder of the steam turbine, thereby increasing the power output of the system, improving the system efficiency, and realizing low-temperature solar energy at the same time. efficient use of

3. With the present invention, when the solar radiation is insufficient during the daytime in winter, part of the low-pressure steam extraction can still be used to heat the low-pressure feedwater, so that the water temperature at the outlet of the low-pressure feedwater heater reaches the design value, ensuring the stable operation of the steam turbine;

4. Utilizing the present invention avoids the mirror field being idle in the long winter, which is conducive to the full utilization of solar energy resources and the investment recovery of the compound parabolic concentrator.

Description of drawings

Fig. 1 is a schematic diagram of a light-coal complementary indirect air-cooled power generation system actively regulated under variable working conditions according to an embodiment of the present invention;

The reference signs are: 1-boiler; 2-high pressure cylinder of steam turbine; 3-medium pressure cylinder of steam turbine; 4-low pressure cylinder of steam turbine; 5-generator; 6-high pressure feed water heater; Oxygenator; 9-low pressure feed water heater; 10-low pressure feed water heater; 11-extraction branch control valve; 12-absorption refrigerator; 13-air-cooled condenser; 14-feed water branch control valve; 15-mirror Field heat exchanger; 16-compound parabolic concentrator (CPC) mirror field.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

As shown in Figure 1, Figure 1 is a schematic diagram of a light-coal complementary indirect air-cooled power generation system actively regulated under variable working conditions according to an embodiment of the present invention. The system includes a boiler 1, a steam turbine high-pressure cylinder 2, a steam turbine medium-pressure cylinder 3, and a steam turbine low-pressure Cylinder 4, generator 5, high-pressure feed water heater 6, high-pressure feed water pump 7, deaerator 8, low-pressure feed water heater 9, low-pressure feed water pump 10, steam extraction flow control valve 11, absorption refrigerator 12, air-cooled condensing device 13, feed water flow path control valve 14, mirror field heat exchanger 15 and compound parabolic concentrator 16, wherein, boiler 1, steam turbine high pressure cylinder 2, steam turbine medium pressure cylinder 3, steam turbine low pressure cylinder 4, generator 5, high pressure Feedwater heater 6, high-pressure feedwater pump 7, deaerator 8, low-pressure feedwater heater 9, low-pressure feedwater pump 10 and air-cooled condenser 13 form a thermal cycle loop; absorption refrigerator 12 and air-cooled condenser 13 form an absorption refrigerator The mirror field heat exchanger 15 and the compound parabolic concentrator 16 constitute the mirror field heat exchanger branch, and the steam turbine low-pressure cylinder 4 and the low-pressure feedwater heater 9 constitute the steam extraction and heating feedwater branch.

Boiler 1 generates main steam, which expands and works through steam turbine high-pressure cylinder 2, steam turbine medium-pressure cylinder 3, and steam turbine low-pressure cylinder 4 in turn, and drives generator 5 to output electric power to the outside; exhaust steam enters air-cooled condenser 13 and is cooled into condensed water, which is supplied by low pressure to The water pump 10 pressurizes, enters the low-pressure feedwater heater 9 for heating, then enters the deaerator 8, and then further pressurizes through the high-pressure feedwater pump 7, enters the high-pressure feedwater heater 6, and after heating to the boiler inlet water temperature requirement, enters the boiler to complete the heat cycle.

During the daytime in summer, when the ambient temperature rises, causing the back pressure of the steam turbine to rise, the extraction flow control valve 11 opens the branch circuit of the absorption refrigerator, and the low-pressure extraction steam of the steam turbine is used to drive the absorption refrigerator, and the inlet air of the air-cooled condenser 13 Cooling is carried out to make the back pressure of the steam turbine close to the design value; at the same time, the feedwater flow control valve 14 opens the mirror field heat exchanger branch, and the compound parabolic concentrator 16 is used to replace the original low-pressure steam extraction to heat the low-pressure feedwater.

During the daytime in winter, when the ambient temperature drops and the steam turbine can maintain the back pressure at the design value, the extraction flow path control valve 11 closes the branch circuit of the absorption refrigerator, and the low-pressure extraction steam of the steam turbine can continue to expand and perform work in the low-pressure cylinder 4 of the steam turbine; at the same time , the feedwater flow path control valve 14 opens the mirror field heat exchanger branch, and enables the compound parabolic concentrator 16 to replace the original low-pressure steam extraction to heat the low-pressure feedwater.

In summer and winter nights, when the ambient temperature drops and the back pressure of the steam turbine can be maintained at the design value, the steam extraction flow control valve 11 closes the branch of the absorption refrigerator, opens the steam extraction to heat the water supply branch, and the low-pressure steam extraction of the steam turbine enters the minimum pressure. The low-pressure feedwater heater 9 restores the function of heating the feedwater; at the same time, the feedwater flow control valve 14 closes the mirror field heat exchanger branch, and the compound parabolic concentrator 16 closes.

The temperature of the driving heat source required by the absorption refrigerator 12 is close to the low-pressure steam extraction temperature of the steam turbine, and the heat collection temperature of the compound parabolic concentrator 16 is close to the heating temperature of the low-pressure feed water. The irreversible loss in the process is the smallest; and because there is a positive correlation between the intensity of solar radiation and the ambient temperature, under different environmental conditions, low-pressure steam extraction can be used to heat the low-pressure feed water, drive absorption refrigeration, and expand and perform work in the low-pressure cylinder of the steam turbine. The active switching of the solar-coal complementary system realizes the active regulation of the indirect refrigeration.

In Fig. 1, the extraction flow path control valve 11 opens the branch circuit of the absorption refrigerator during the daytime in summer, and its flow control depends on the increase of the ambient temperature, which leads to the increase of the temperature of the inlet air of the condenser. The air temperature is cooled to the design value. The extraction flow path control valve 11 closes the branch circuit of the absorption refrigerator during the daytime in winter, and the extraction steam expands in the low-pressure cylinder of the steam turbine to do work; Entering the low-pressure feed water heater, its flow control depends on the solar radiation, and its heat release is enough to heat the remaining feed water to the design temperature. The feed water flow path control valve 14 opens the branch of the mirror field heat exchanger during the daytime in summer and winter, and its flow control depends on the solar radiation, so that the heat collected by the compound parabolic concentrator 16 will enter the feed water of the mirror field heat exchanger branch. Heat to design temperature. The mirror field heat exchanger 15 is connected in parallel with the low-pressure feed water heater 9, and runs in series with the rest of the feed water heaters in the power station recuperation system. The low-pressure extraction steam driven by the absorption refrigerating machine 12, after releasing heat and condensing in the refrigerating machine, gathers with other condensed water at the outlet of the air-cooled condenser 13, and participates in the thermodynamic cycle of the unit again.

Based on the light-coal complementary indirect air-cooled power generation system actively regulated under variable working conditions shown in Figure 1, the present invention also provides a light-coal complementary indirect air-cooled power generation method actively regulated under variable working conditions, the method comprising:

Boiler 1 generates main steam, which expands and works through steam turbine high-pressure cylinder 2, steam turbine medium-pressure cylinder 3, and steam turbine low-pressure cylinder 4 in turn, and drives generator 5 to output electric power to the outside; exhaust steam enters air-cooled condenser 13 and is cooled into condensed water, which is supplied by low pressure to The water pump 10 pressurizes, enters the low-pressure feedwater heater 9 for heating, then enters the deaerator 8, and then further pressurizes through the high-pressure feedwater pump 7, enters the high-pressure feedwater heater 6, and after heating to the boiler inlet water temperature requirement, enters the boiler to complete the heat cycle;

During the daytime in summer, when the ambient temperature rises and the back pressure of the steam turbine rises, the extraction flow control valve opens the branch circuit of the absorption refrigerator, and the low-pressure extraction steam of the steam turbine is used to drive the absorption refrigerator to cool the air at the inlet of the air-cooled condenser , so that the back pressure of the steam turbine is close to the design value; at the same time, the feedwater flow control valve opens the mirror field heat exchanger branch, and the compound parabolic concentrator is used to replace the original low-pressure steam extraction to heat the low-pressure feedwater;

During the winter day, when the ambient temperature drops and the steam turbine can maintain the back pressure at the design value, the extraction flow control valve closes the branch circuit of the absorption refrigerator, and the low-pressure extraction steam of the steam turbine can continue to expand and work in the low-pressure cylinder of the steam turbine; at the same time, the The water flow control valve opens the mirror field heat exchanger branch, and enables the compound parabolic concentrator to replace the original low-pressure steam extraction to heat the low-pressure feed water;

In summer and winter nights, when the ambient temperature drops and the back pressure of the steam turbine can be maintained at the design value, the steam extraction flow control valve closes the branch of the absorption refrigerator, opens the steam extraction heating water supply branch, and the low-pressure steam extraction of the steam turbine enters the lowest pressure The low-pressure feed water heater restores the function of heating the feed water; at the same time, the feed water flow control valve closes the branch of the mirror field heat exchanger, and the mirror field of the compound parabolic concentrator is closed.

In a specific embodiment provided by the present invention, the average daily temperature in summer in the vast southern regions of China (Zhejiang Province, Jiangsu Province, etc.) is relatively high, and solar radiation resources are abundant at the same time. Retrofit, the design back pressure of the unit is 15kPa, the design air temperature is 17°C, the design value of the inlet/outlet water temperature of the low-pressure feed water heater of the unit under rated working conditions is 55.4/93.1°C, and the thermal parameters of the original three-stage low-pressure extraction steam are 290.8°C/ 0.5969MPa; 208.5°C/0.2692MPa; 106.4°C/0.0918MPa. The annual operating hours of the unit are about 5000, including 3000 hours in summer and 2000 hours in winter.

During the daytime in summer, the average daily temperature is nearly 27°C. For units without complementary transformation, the back pressure rises to 30kPa, the power drops to 310MW, and the power generation efficiency drops from 40.8% to 38.3%, a drop of 2.5 percentage points in efficiency. The invention uses the original low-pressure extraction to drive a single-effect lithium bromide absorption refrigerating unit to reduce the inlet air temperature of the air-cooling unit. The design wind speed of the original air-cooling unit is 2.15m/s, the design windward area is 5368m ² , the temperature of the selected refrigeration unit is above 85°C, and the COP is 0.7. In order to realize the cooling of the air-cooling unit, the heat required to drive the absorption refrigeration unit is 212.7MW, while the total heat release of low-pressure extraction steam is 96MW, which can reduce the air temperature by 4.5 degrees, the back pressure drop to 25kPa, and the power increased to 317MW. It is expected to increase the power generation by 21GWh throughout the summer, and the power generation efficiency of the unit is 39.2%. , using the CPC compound parabolic concentrator to obtain hot water with an inlet/outlet temperature of 75/174°C, replacing the original unit with low-pressure steam extraction to heat the feedwater to the design temperature.

During the daytime in winter, when the daily average temperature is below the design temperature, the air cooling unit is operating normally, and the original low-pressure extraction steam can continue to expand and work in the low-pressure cylinder of the steam turbine. It is expected to increase the power generation by 20GWh throughout the winter, and the power generation efficiency will increase to 42.0%. At the same time, the CPC The composite parabolic concentrator obtains hot water with an inlet/outlet temperature of 75/174°C, replacing the original unit with low-pressure steam extraction to heat the feed water to the design temperature, which can realize efficient utilization of low-temperature solar energy, and the net solar power generation efficiency reaches 12%. In summer and winter nights, the thermal power unit returns to the original operation mode, the low-pressure extraction steam is still used to heat the low-feed water, and the compound parabolic concentrator is closed to ensure the safe and stable operation of the unit.

To sum up, the use of solar energy to carry out complementary transformation of thermal power units to achieve indirect air cooling is expected to achieve a substantial increase in annual power generation. The annual power generation efficiency of the unit reaches 40.3%, even exceeding the design level of the unit, and the solar heat collecting mirror field is fully utilized in winter to realize high-efficiency power generation of low-temperature solar energy.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (13)

1. the complementary indirect air cooling power generation system of the light coal of a variable working condition active control, it is characterized in that, this system comprises boiler (1), steam turbine high-pressure cylinder (2), Steam Turbine Through IP Admission (3), turbine low pressure cylinder (4), generator (5), high-pressure feed-water heater (6), high pressure water pump (7), oxygen-eliminating device (8), low-pressure feed heater (9), low pressure feed water pump (10), draw gas flow circuit control valve (11), Absorption Refrigerator (12), air-cooled condenser (13), feedwater flow circuit control valve (14), mirror field heat exchanger (15) and compound parabolic concentrator (16), wherein:

Boiler (1), steam turbine high-pressure cylinder (2), Steam Turbine Through IP Admission (3), turbine low pressure cylinder (4), generator (5), high-pressure feed-water heater (6), high pressure water pump (7), oxygen-eliminating device (8), low-pressure feed heater (9), low pressure feed water pump (10) and air-cooled condenser (13) form thermodynamic cycle loop; Absorption Refrigerator (12) and air-cooled condenser (13) form Absorption Refrigerator branch road, mirror field heat exchanger (15) and compound parabolic concentrator (16) form mirror field heat exchanger branch road, and turbine low pressure cylinder (4) and low-pressure feed heater (9) form the heated feed water branch road that draws gas;

Boiler (1) produces main steam, and successively by steam turbine high-pressure cylinder (2), Steam Turbine Through IP Admission (3), turbine low pressure cylinder (4) expansion working, drive electrical generators (5) is electromotive power output externally; Exhaust steam enters air-cooled condenser (13) and is cooled to condensed water, pressurizeed by low pressure feed water pump (10), enter low-pressure feed heater (9) heating, then enter oxygen-eliminating device (8), pressurizeed further by high pressure water pump (7) again, enter high-pressure feed-water heater (6), after being heated to the requirement of boiler inlet water temperature, enter boiler, complete thermodynamic cycle;

At summer day, ambient temperature raises, when causing turbine back pressure to rise, the flow circuit control valve (11) that draws gas opens Absorption Refrigerator branch road, steam turbine low-pressure draws gas for driving Absorption Refrigerator, air-cooled condenser (13) intake air is cooled, makes turbine back pressure close to design load; Meanwhile, mirror field heat exchanger branch road is opened in feedwater flow circuit control valve (14), enables compound parabolic concentrator (16), substitutes former low-pressure pumping steam heating low pressure feed water;

On daytime in the winter time, ambient temperature declines, and steam turbine can maintain back pressure when being design load, and the flow circuit control valve that draws gas (11) closes Absorption Refrigerator branch road, and steam turbine low-pressure draws gas and can continue expansion working in turbine low pressure cylinder (4); Meanwhile, mirror field heat exchanger branch road is opened in feedwater flow circuit control valve (14), enables compound parabolic concentrator (16), substitutes former low-pressure pumping steam heating low pressure feed water;

At summer and night in winter, ambient temperature declines, steam turbine can maintain back pressure when being design load, the flow circuit control valve (11) that draws gas closes Absorption Refrigerator branch road, unlatching is drawn gas heated feed water branch road, steam turbine low-pressure draws gas the low-pressure feed heater (9) entering minimal pressure, recovery heating feeding water function; Meanwhile, a heat exchanger branch road of covering the lens is closed in feedwater flow circuit control valve (14), and compound parabolic concentrator (16) is closed.

2. the complementary indirect air cooling power generation system of the light coal of variable working condition active control according to claim 1, it is characterized in that, the required driving heat source temperature of described Absorption Refrigerator (12) and steam turbine low-pressure extraction temperature close, compound parabolic concentrator (16) heat-collecting temperature and low pressure feed water heating-up temperature close, system ensure that in newly-increased flow process, irreversible loss is minimum while realizing indirect air cooling, raising steam turbine cycle efficiency; And there is positive association relation due to solar irradiance intensity and ambient temperature, under varying environment condition by low-pressure pumping steam at heating low pressure feed water, drive absorption refrigeration, active between turbine low pressure cylinder expansion working three functions switches, and realizes the active control of light coal complementary system indirect refrigeration.

3. the complementary indirect air cooling power generation system of the light coal of variable working condition active control according to claim 1, it is characterized in that, the described flow circuit control valve that draws gas (11) opens Absorption Refrigerator branch road at summer day, its flow control depends on that ambient temperature raises, cause condenser inlet air temperature elevated-levels, meeting refrigerating capacity of drawing gas can be cooled to design load by air temperature as far as possible.

4. the complementary indirect air cooling power generation system of the light coal of variable working condition active control according to claim 1, it is characterized in that, the described flow circuit control valve that draws gas (11) closes Absorption Refrigerator branch road daytime in the winter time, draws gas at turbine low pressure cylinder expansion working; When compound parabolic concentrator (16) heat-collecting capacity can not meet low pressure feed water demand for heat completely, part is drawn gas and is still entered low-pressure feed heater, solar irradiance situation is depended in its flow control, meets its thermal discharge and enough residue feedwater is heated to design temperature.

5. the complementary indirect air cooling power generation system of the light coal of variable working condition active control according to claim 1, it is characterized in that, described feedwater flow circuit control valve (14) opens mirror field heat exchanger branch road in summer and daytime in winter, solar irradiance situation is depended in its flow control, meets compound parabolic concentrator (16) heat-collecting capacity and the feedwater entering mirror field heat exchanger branch road is heated to design temperature.

6. the complementary indirect air cooling power generation system of the light coal of variable working condition active control according to claim 1, it is characterized in that, described mirror field heat exchanger (15) is in parallel with low-pressure feed heater (9), with all the other the feed water preheater series operations in the heat regenerative system of power station.

7. the complementary indirect air cooling power generation system of the light coal of variable working condition active control according to claim 1, it is characterized in that, the low-pressure pumping steam of described driving Absorption Refrigerator (12), in refrigerator after exothermic condensation, collect with other condensed waters in air-cooled condenser (13) outlet, again participate in the thermodynamic cycle of unit.

8. the complementary indirect air cooling electricity-generating method of the light coal of variable working condition active control, be applied to the system according to any one of claim 1 to 7, the method comprises:

Boiler (1) produces main steam, and successively by steam turbine high-pressure cylinder (2), Steam Turbine Through IP Admission (3), turbine low pressure cylinder (4) expansion working, drive electrical generators (5) is electromotive power output externally; Exhaust steam enters air-cooled condenser (13) and is cooled to condensed water, pressurizeed by low pressure feed water pump (10), enter low-pressure feed heater (9) heating, then enter oxygen-eliminating device (8), pressurizeed further by high pressure water pump (7) again, enter high-pressure feed-water heater (6), after being heated to the requirement of boiler inlet water temperature, enter boiler, complete thermodynamic cycle;

At summer day, ambient temperature raises, when causing turbine back pressure to rise, the flow circuit control valve that draws gas opens Absorption Refrigerator branch road, steam turbine low-pressure draws gas for driving Absorption Refrigerator, cools air-cooled condenser intake air, makes turbine back pressure close to design load; Meanwhile, feedwater flow circuit control valve opens mirror field heat exchanger branch road, enables compound parabolic concentrator, substitutes former low-pressure pumping steam heating low pressure feed water;

On daytime in the winter time, ambient temperature declines, and steam turbine can maintain back pressure when being design load, and the flow circuit control valve that draws gas closes Absorption Refrigerator branch road, and steam turbine low-pressure draws gas and can continue expansion working in turbine low pressure cylinder; Meanwhile, feedwater flow circuit control valve opens mirror field heat exchanger branch road, enables compound parabolic concentrator, substitutes former low-pressure pumping steam heating low pressure feed water;

At summer and night in winter, ambient temperature declines, and steam turbine can maintain back pressure when being design load, the flow circuit control valve that draws gas closes Absorption Refrigerator branch road, unlatching is drawn gas heated feed water branch road, and steam turbine low-pressure draws gas and enters the low-pressure feed heater of minimal pressure, recovery heating feeding water function; Meanwhile, feedwater flow circuit control valve closes a heat exchanger branch road of covering the lens, and compound parabolic concentrator Jing Chang closes.

9. the complementary indirect air cooling electricity-generating method of the light coal of variable working condition active control according to claim 8, it is characterized in that, the described flow circuit control valve that draws gas (11) opens Absorption Refrigerator branch road at summer day, its flow control depends on that ambient temperature raises, cause condenser inlet air temperature elevated-levels, namely meeting refrigerating capacity of drawing gas can be cooled to design load by air temperature as far as possible.

10. the complementary indirect air cooling electricity-generating method of the light coal of variable working condition active control according to claim 8, it is characterized in that, the flow circuit control valve (11) that draws gas closes Absorption Refrigerator branch road daytime in the winter time, and drawing gas can at turbine low pressure cylinder expansion working; When compound parabolic concentrator (16) heat-collecting capacity can not meet low pressure feed water demand for heat completely, part is drawn gas and is still entered low-pressure feed heater, solar irradiance situation is depended in its flow control, meets its thermal discharge and enough residue feedwater is heated to design temperature.

The complementary indirect air cooling electricity-generating method of light coal of 11. variable working condition active controls according to claim 8, it is characterized in that, described feedwater flow circuit control valve (14) opens mirror field heat exchanger branch road in summer and daytime in winter, solar irradiance situation is depended in its flow control, meets compound parabolic concentrator (16) heat-collecting capacity and the feedwater entering mirror field heat exchanger branch road is heated to design temperature.

The complementary indirect air cooling electricity-generating method of light coal of 12. variable working condition active controls according to claim 8, it is characterized in that, the complementary indirect air cooling power generation system of light coal of described variable working condition active control according to claim 1, it is characterized in that, described mirror field heat exchanger (15) is in parallel with low-pressure feed heater (9), with all the other the feed water preheater series operations in the heat regenerative system of power station.

The complementary indirect air cooling electricity-generating method of light coal of 13. variable working condition active controls according to claim 8, it is characterized in that, the low-pressure pumping steam of described driving Absorption Refrigerator (12), in refrigerator after exothermic condensation, collect with other condensed waters in air-cooled condenser (13) outlet, again participate in the thermodynamic cycle of unit.