CN116658908A - Waste incineration power plant electric power consumption system based on incineration fly ash regenerated salt heat storage - Google Patents

Abstract

The invention relates to a garbage incineration and fused salt heat storage technology, and aims to provide a garbage incineration power plant power consumption system based on regenerated salt heat storage of incineration fly ash. The system comprises a flue gas temperature stabilizer and a flue gas-molten salt heat exchanger which are arranged in a flue, wherein both the flue gas temperature stabilizer and the molten salt-steam reheater take molten salt as an internal heat exchange medium, and an external heat exchange medium of the flue gas temperature stabilizer and the flue gas-molten salt heat exchanger is steam from an extraction opening of a steam turbine; the top of the high-temperature molten salt tank is sequentially connected with a molten salt pump, a molten salt-steam reheater and a molten salt inlet at the top of the low-temperature molten salt tank through pipelines; the outlet at the bottom of the low-temperature molten salt tank is divided into two paths, one path is sequentially connected with the molten salt pump, the flue gas-molten salt heat exchanger, the flue gas temperature stabilizer and the high-temperature molten salt tank, and the other path is sequentially connected with the molten salt pump, the electric heater and the high-temperature molten salt tank. According to the invention, the stable output power of the waste incineration power plant and peak clipping and valley filling are realized through the fused salt heat storage, and the power generation allowance of the power plant is consumed; realizes the efficient reuse of high-chlorine waste salt in the waste incineration fly ash, and has the advantages of cleanness, no pollution and low cost.

Description

Power consumption system of waste incineration power plant based on incineration fly ash and regenerated salt heat storage

technical field

The invention relates to the technical field of waste incineration and molten salt heat storage, in particular to a power consumption system for waste incineration power plants based on heat storage of regenerated salt from incineration fly ash.

Background technique

Under the background of double carbon, renewable new energy has become the main body of new installed capacity of electric power. Due to the large fluctuations in the power generation of new energy sources, the periodic load fluctuations of the power grid are increased. In this context, the consumption capacity of "abandoned wind" and "abandoned light" has become a restrictive factor for the further development of new energy. Therefore, each power plant also undertakes the tasks of energy storage peak regulation and abandoned power consumption.

Because waste incineration has the advantages of good volume reduction, high degree of harmlessness, and energy recovery, it is often used for power generation and is also a new energy power generation technology. However, due to the large changes in the characteristics of waste combustion, such as calorific value, water content, and waste volume, the incinerator has the problem of unstable flue gas temperature and difficult regulation, which easily leads to waste of excess power generation and increased heat loss from exhaust gas. Therefore, waste incineration power plants not only lack energy storage and peak-shaving capabilities, but also impose a greater burden on the power grid. In order to avoid power waste, it is necessary to improve the peak-shaving capacity of energy storage to reduce the burden on the power grid, and contribute to the surplus consumption capacity of new energy generation.

Among the main energy storage technologies, pumped storage and heat storage technologies have a high energy conversion rate to electric energy, are reliable in technology, and low in cost, and are suitable for energy storage peak regulation in power plants. Among them, pumped storage has a long service life, a large capacity, and a long energy storage period. However, waste incineration power plants are usually located in the surrounding areas of cities and towns. Therefore, pumped storage is limited by natural conditions and cannot be popularized and applied in plain areas and cannot meet the energy storage needs of relatively small-scale waste incineration power plants.

The heat storage technology represented by molten salt occupies a small area, has a high energy storage density, and is easy to couple with the power generation system. However, the current conventional molten salt material belongs to the nitrate system, which is easy to decompose at high temperature, has low heat storage grade and high cost. Therefore, the mainstream molten salt heat storage system is usually used for low-temperature heat storage in photothermal power plants, which is not suitable for waste incinerators, and has no effect on improving the working conditions of incinerators.

To sum up, the various defects in the existing technology make it impossible to meet the peak-shaving demand for clean energy storage in waste incineration power plants, and cannot realize the optimization of incineration performance and the utilization of regenerated salt. Therefore, it is necessary to develop a new energy storage system, which is based on the characteristics of waste incineration power plants and can make full use of the characteristics of fly ash regenerated salt to achieve flexible peak regulation and power consumption.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a waste incineration power plant power consumption system based on heat storage of regenerated salt from incineration fly ash.

For solving technical problem, solution of the present invention is:

Provide a waste incineration power plant power consumption system based on incineration fly ash regenerated salt heat storage, including high temperature molten salt tank, low temperature molten salt tank installed in the waste incineration power plant, as well as a flue temperature stabilizer as heat exchange equipment, flue gas - Molten salt heat exchangers, molten salt-steam reheaters and electric heaters; of which,

The flue gas temperature stabilizer and the flue gas-molten salt heat exchanger are sequentially arranged in the flue behind the incinerator along the flue gas flow direction, both of which use flue gas as the external heat exchange medium and molten salt as the internal heat exchange medium; molten salt- The internal heat exchange medium of the steam reheater is molten salt, and the external heat exchange medium is steam from the exhaust port of the steam turbine, which is connected to the generator set of the waste incineration power plant; the molten salt is the waste incineration fly ash washed with water and evaporated The regenerated salt obtained by crystallization has a melting point of ≤550°C and a mass loss of less than 5% in 5 hours at 1.01×10 ⁵ Pa and 850°C, so that it can meet the heat storage operation requirements in the range of 600-850°C;

The molten salt outlet on the top of the high-temperature molten salt tank is sequentially connected to the molten salt pump, the molten salt-steam reheater and the molten salt inlet on the top of the low-temperature molten salt tank through pipelines; there are two molten salt tanks at the bottom of the low-temperature molten salt tank Outlets, one of which is sequentially connected to the molten salt pump, flue gas-molten salt heat exchanger, flue gas temperature stabilizer and molten salt inlet at the bottom of the high-temperature molten salt tank through pipelines, and the other outlet is connected to the molten salt pump, Electric heater and molten salt inlet at the bottom of the high temperature molten salt tank.

As a preferred solution of the present invention, the main body of the high-temperature molten salt tank and the low-temperature molten salt tank is a cylinder with a sealed structure, and an electric heating module is arranged outside the cylinder.

As a preferred solution of the present invention, all electrical equipment in the system are connected to the power supply system of the waste incineration power plant through cables to realize self-generated power supply.

As a preferred solution of the present invention, the electric heater is also connected to an external power source through a cable, and the external power source is wind power generation equipment, photovoltaic power generation equipment, hydroelectric power generation equipment or a public power grid.

As a preferred solution of the present invention, in the flue gas-molten salt heat exchanger, the flue gas and the molten salt are arranged countercurrently; in the molten salt-steam reheater, the molten salt is arranged countercurrently with the steam; in the flue gas temperature stabilizer, The flue gas and molten salt are arranged downstream; a bypass pipeline is provided between the molten salt inlet and outlet of the flue temperature stabilizer.

The present invention further provides a method for realizing heat storage and power consumption of regenerated salt in a waste incineration power plant by using the aforementioned system, including:

(1) The flue gas at the furnace outlet of the incinerator in the waste incineration power plant flows through the flue gas temperature stabilizer and the flue gas-molten salt heat exchanger in turn, and enters the exhaust gas purification system after exchanging heat with the molten salt inside the two;

(2) The steam from the steam extraction port of the steam turbine enters the molten salt-steam reheater to exchange heat with the molten salt extracted from the high-temperature molten salt tank, and the heated steam is sent back to the steam turbine to release heat and perform work for power generation; after cooling The molten salt is sent to the low temperature molten salt tank;

(3) The molten salt is extracted from the low-temperature molten salt tank and sent to the electric heater and the flue gas-molten salt heat exchanger respectively; the molten salt is heated in the electric heater to absorb the power surplus of the power plant or external power supply amount; the molten salt exchanges heat with the flue gas countercurrently in the flue gas-molten salt heat exchanger, which is used to absorb the waste heat of the flue gas; Gas temperature; the molten salt that is further heated after absorbing heat is sent back to the high-temperature molten salt tank to reduce the inhomogeneity of the temperature distribution in the tank;

(4) In the flue gas temperature stabilizer, part of the molten salt flows back to the inlet from the outlet through the bypass pipeline, which is used to adjust the molten salt flow rate to stabilize the flue gas temperature, so that the residence time of the flue gas in the temperature range above 850 ° C is extended to At least 5 seconds to promote the decomposition of organic matter including dioxins.

As a preferred solution of the present invention, the temperature of the molten salt in the high-temperature molten salt tank and the low-temperature molten salt tank is controlled to be 850±20°C and 600±15°C respectively; the temperature of the molten salt at the inlet of the smoke temperature stabilizer is 800±10°C, The temperature of the molten salt at the outlet is 850±10°C; the temperature of the molten salt at the outlet of the flue gas-molten salt heat exchanger, molten salt-steam reheater and electric heater is respectively consistent with the temperature of the molten salt at the corresponding arrival position .

As a preferred solution of the present invention, the external heat exchange medium of the flue gas temperature stabilizer is the flue gas at the outlet of the incinerator, the temperature at the inlet side is 950±50°C, and the temperature at the outlet side is 850±10°C; flue gas-molten salt heat exchange The external heat exchange medium of the device is the flue gas from the outlet of the flue gas temperature stabilizer, the temperature of the inlet side is 850±10°C, and the temperature of the outlet side is 650±15°C; the temperature of the tube wall of the electric heater is 950±50°C; On the steam side of the molten salt-steam reheater, the steam parameters at the inlet are 0.6MPa, 248°C, and the steam parameters at the outlet are 3.82MPa, 435°C.

As a preferred solution of the present invention, valves are used to control the flow of molten salt entering the flue gas-molten salt heat exchanger, molten salt-steam reheater, electric heater and flue gas temperature stabilizer bypass pipeline; wherein the flue gas-melt The molten salt flow rate of the salt heat exchanger is adjusted according to the molten salt temperature at the outlet side; the molten salt flow rate of the molten salt-steam reheater is adjusted according to the steam temperature at the outlet side; the molten salt flow rate of the electric heater is adjusted according to the molten salt temperature at the outlet side Adjustment; the flow of molten salt in the bypass line of the flue temperature stabilizer is adjusted according to the flue gas temperature at the outlet side.

As a preferred version of the present invention, the molten salt is a regenerated salt produced by evaporation and crystallization after the waste incineration fly ash water elutes the salt, and the composition is a ternary eutectic chlorine salt comprising NaCl, KCl and _CaCl ; the ternary eutectic chlorine The melting point of the salt is ≤ 550°C, and the mass loss is < 5% in 5h at 1.01×10 ⁵ Pa and 850°C.

Description of invention principle:

Molten salt heat storage is a high-efficiency, energy-saving and reliable peak-shaving method, which can effectively stabilize the output power of the power plant, cut peaks and fill valleys for periodically fluctuating loads, and reduce curtailment of light and wind. Due to large fluctuations in output power, waste incineration power plants lack load regulation capabilities and the waste of salt in fly ash is serious.

The content of chlorine salt in the fly ash of waste incineration accounts for 25-50%, which not only easily penetrates into the soil and groundwater with precipitation, but also has a serious adverse effect on the fly ash disposal process. The proper disposal is the harmless disposal and recycling of fly ash The key link to use. Usually, the fly ash chlorine salt is separated by water washing, and the waste salt is landfilled by evaporation and crystallization of the waste liquid of water washing, or the pure salt is extracted by fractional crystallization. Among them, the landfill method is facing elimination, and the existing fractional crystallization process has problems of high energy consumption, a large amount of waste of calcium salt, a large amount of heavy metal-containing precipitates, and low product acceptance. There is an urgent need for an integrated fly ash regeneration salt Utilize the method to achieve efficient regeneration. Fly ash regeneration salt belongs to the NaCl-KCl-CaCl ₂ multi-chlorine salt system, which has a higher upper temperature limit compared with nitrate, so it can store high-grade heat energy of waste incinerator flue gas, and can achieve higher thermal-electricity conversion rate.

For this reason, the present invention couples molten salt heat storage with a waste incineration power plant, and uses a new type of regenerated salt extracted from waste incineration fly ash as a low-cost clean heat storage medium, and can absorb the power generation surplus of the power plant, realizing stable output power, cutting Fill peaks and valleys, absorb and discard electricity, clean energy storage, improve thermal efficiency and stabilize the working conditions of heat exchangers.

Main technical principle of the present invention is as follows:

(1) Energy storage peak regulation and combustion improvement

(1) When the load peaks, the molten salt-steam reheater starts to generate high-pressure steam for power generation; when the load is low, the molten salt-steam reheater stops running. Valves are used to control the molten salt flow into the flue gas-molten salt heat exchanger, molten salt-steam reheater, electric heater and bypass pipeline of the flue gas temperature stabilizer. Among them: the molten salt flow rate of the flue gas-molten salt heat exchanger is adjusted according to the molten salt temperature at the outlet side to ensure heat transfer; the molten salt flow rate of the molten salt-steam reheater is adjusted according to the steam temperature at the outlet side to ensure that the steam turbine enters steam temperature; the molten salt flow rate of the electric heater is adjusted according to the molten salt temperature on the outlet side to maintain the outlet molten salt temperature. The flow of molten salt in the bypass pipeline of the flue gas temperature stabilizer is adjusted according to the flue gas temperature at the outlet side to stabilize the flue gas temperature at the outlet.

(2) The first low-temperature molten salt pump transports the low-temperature molten salt in the low-temperature molten salt tank to the flue gas-molten salt heat exchanger, absorbs the residual temperature of the flue gas, and then sends it to the flue temperature stabilizer for further heat exchange; absorbs high-temperature flue gas The heated molten salt is stored in a high-temperature molten salt tank with high heat storage grade. The second low-temperature molten salt pump transports the molten salt in the low-temperature molten salt tank to the electric heater, and the heated molten salt is stored in the high-temperature molten salt tank, which can absorb the power generation surplus of the power plant or external power supply system. The high-temperature molten salt pump transports the molten salt in the high-temperature molten salt tank to the flue gas-steam reheater to release heat, which is used to produce high-temperature and high-pressure steam that can meet the steam inlet requirements of the steam turbine.

(3) The essence of the smoke temperature stabilizer is a high-temperature heat exchanger used to increase the turbulence of the high-temperature flue and prolong the high-temperature residence time. It can cover the surface of the high-temperature flue and protect the wall of the flue. Through the combined use of the flue gas temperature stabilizer and the flue gas-molten salt heat exchanger, the fluctuation of the flue gas temperature in the flue is small, the working state of the heating surface of the flue is stable, and the fluctuation of the exhaust gas temperature is small. Therefore, the present invention can solve the problems of large heat loss caused by too high exhaust gas temperature, regeneration of dioxin and thermal desorption of dioxin in fly ash, and aggravated low-temperature corrosion caused by too low exhaust gas temperature. It can not only prolong the residence time of flue gas above 850°C and promote the pyrolysis of dioxins; it can also achieve a lower design value of exhaust gas temperature and reduce the inherent heat loss of exhaust gas.

(2) New regenerative salt clean heat storage materials

(1) Traditional molten salt heat storage materials usually use polybasic nitrates, whose operating temperature is usually between 250°C and 600°C, which has the characteristics of pyrolysis and is not suitable for high-temperature flue gas heat storage. The multi-component chlorine salt used in the present invention has a relatively higher melting point and stronger thermal stability, and can operate at 600-850°C. Therefore, the grade of heat storage is higher and the cost is lower, which is conducive to improving the heat-to-electricity conversion rate, and is a new type of molten salt heat storage material.

(2) Garbage incineration fly ash contains a large amount of NaCl, KCl and CaCl ₂ . In the process of disposal, the salt is often extracted by water washing and the washing waste liquid is evaporated and crystallized to obtain multi-component mixed chlorine salts. The cost is much lower than that of finished single salt or multi-component nitric acid. Salt. The heat storage and utilization of regenerative salt provides an integrated application scenario of fly ash chloride salt. Compared with the traditional process, it does not need to remove all calcium, has a high recycling rate, and avoids high-energy-consuming fractional crystallization, providing fly ash chloride salt resources. The chemical process provides a new solution for high efficiency and energy saving.

(3) Dioxin and other organic pollutants in waste salt are completely degraded through high-temperature heat treatment, and there is no risk of heavy metals and other pollutants escaping in a closed operating environment. Through the integrated application, the generation of a large amount of calcium-based precipitates containing heavy metals in the process of regenerated salt disposal is avoided.

Compared with the prior art, the beneficial effects of the present invention are as follows:

(1) The present invention can realize stable output power of waste incineration power plants, peak shaving and valley filling through molten salt heat storage, and absorb power generation surplus of power plants.

(2) The molten salt used in the present invention is used as a high-temperature heat exchange medium, which is safe and stable, has high energy storage grade, and high heat-to-electricity conversion rate.

(3) The present invention can directly recycle and use the molten salt inside the waste incineration power plant, realizes efficient reuse of high-chlorine waste salt in waste incineration fly ash, is clean and pollution-free, and has low cost of heat storage materials.

(4) The present invention can stabilize flue gas temperature, improve the working conditions of the heat exchange surface, reduce the emission of dioxin and other pollutants, and absorb fly ash regeneration salt.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Fig. 2 is a schematic diagram of the system structure of the present invention.

The reference signs in the figure are: 1-high temperature molten salt tank, 2-low temperature molten salt tank, 3-molten salt-steam reheater, 4-flue gas-molten salt heat exchanger, 5-flue temperature stabilizer, 6 -electric heater, 7-high temperature molten salt pump, 8-first low temperature molten salt pump, 9-second low temperature molten salt pump, 10-high temperature molten salt valve, 11-first low temperature molten salt valve, 12-second Low temperature molten salt valve, 13-bypass valve.

Detailed ways

The main heat exchange medium used in the present invention is molten salt, and the regenerated salt obtained from waste incineration fly ash through water elution and evaporation crystallization is a ternary eutectic chlorine salt containing NaCl, KCl and CaCl ₂ . The preparation process of the molten salt can adopt the existing disclosed technology, such as the molten salt processing described in the Chinese invention patent application "a ternary chloride molten salt with high temperature thermal stability and its preparation method" (notification number: CN113372886A) technology. The present invention only proposes product performance requirements for molten salt: melting point ≤ 550°C, and 5h mass loss at 1.01×10 ⁵ Pa and 850°C < 5%, so that it can meet the heat storage operation requirements in the range of 600-850°C . As for the specific component ratio relationship and production process parameters of the molten salt, there is no special requirement in the present invention.

In the present invention, the main body of the high-temperature molten salt tank and the low-temperature molten salt tank is a cylinder with a sealed structure, and an electric heating module is arranged outside the cylinder; high temperature and low temperature only represent the difference between the temperature of the molten salt inside the molten salt tank. the difference. The temperature can be achieved by adjusting the heat exchange equipment connected to the tank and the amount of flue gas exchange, as well as adjusting the power of the external electric heating module, and there is no special requirement for the tank itself. The same is true for the limitation of high temperature and low temperature of molten salt pump in the following text. In addition, the flue gas temperature stabilizer, flue gas-molten salt heat exchanger, molten salt-steam reheater, and electric heater are all heat exchange equipment, and the related equipment can be processed in a conventional manner, and there is no special requirement in the present invention.

The present invention will be further elaborated below by means of embodiments in conjunction with the accompanying drawings, but the present invention is not limited.

As shown in Figures 1 and 2, the power consumption system of a waste incineration power plant includes a high-temperature molten salt tank 1 and a low-temperature molten salt tank 2 installed in the waste incineration power plant, as well as a molten salt-steam reheater 3 as heat exchange equipment, and a smoke Gas-molten salt heat exchanger 4, smoke temperature stabilizer 5 and electric heater 6; wherein, the main body of high-temperature molten salt tank 1 and low-temperature molten salt tank 2 is a cylinder with a sealed structure. Electric heating module.

The flue gas temperature stabilizer 5 and the flue gas-molten salt heat exchanger 4 are sequentially arranged in the flue behind the incinerator along the flue gas flow direction, both of which use flue gas as the external heat exchange medium and molten salt as the internal heat exchange medium. The internal heat exchange medium of the molten salt-steam reheater 3 is molten salt, and the external heat exchange medium is steam from the exhaust port of the steam turbine, which is connected with the generator set of the waste incineration power plant. In the flue gas-molten salt heat exchanger 4, the flue gas and molten salt are arranged countercurrently; in the molten salt-steam reheater 3, the molten salt and steam are arranged countercurrently; The salt is arranged downstream; a bypass pipeline is provided between the molten salt inlet and outlet of the smoke temperature stabilizer 5 .

The molten salt outlet on the top of the high-temperature molten salt tank 1 is connected to the high-temperature molten salt valve 10, the high-temperature molten salt pump 7, the molten salt-steam reheater 3, and the molten salt inlet on the top of the low-temperature molten salt tank 2 through pipelines. There are two molten salt outlets at the bottom of the low temperature molten salt tank 2, one of which is connected to the first low temperature molten salt valve 11, the first low temperature molten salt pump 8, the flue gas-molten salt heat exchanger 4, The smoke temperature stabilizer 5 and the molten salt inlet at the bottom of the high-temperature molten salt tank 1, and the other outlet is sequentially connected to the second low-temperature molten salt valve 12, the second low-temperature molten salt pump 9, the electric heater 6 and the high-temperature molten salt tank through pipelines 1 Molten salt inlet at the bottom.

In this system, all electrical equipment is connected to the power supply system of the waste incineration power plant through cables to realize self-generated power supply. The electric heater 6 is also connected to an external power source through a cable for consuming surplus electricity, and the external power source may be wind power generation equipment, photovoltaic power generation equipment, hydroelectric power generation equipment or a public power grid.

The above system can be used to realize heat storage and power consumption of regenerated salt in waste incineration power plants. The specific implementation methods include the following:

(1) The flue gas at the furnace outlet of the incinerator in the waste incineration power plant flows through the flue gas temperature stabilizer 5 and the flue gas-molten salt heat exchanger 4 in sequence, then continues to pass through the superheater, economizer and air preheater, and finally enters the exhaust gas purification system;

(2) Send the steam from the steam extraction port of the steam turbine into the molten salt-steam reheater 3 to exchange heat with the molten salt extracted from the high-temperature molten salt tank 1, and the heated high-pressure steam is sent back to the steam turbine to release heat and perform work To generate electricity, the molten salt after cooling is sent into the low-temperature molten salt tank 2;

(3) The molten salt is extracted from the low-temperature molten salt tank 2 and sent to the electric heater 6 and the flue gas-molten salt heat exchanger 4 respectively. The molten salt is heated in the electric heater 6, which is used to absorb the power surplus of the power plant or external power supply; the molten salt exchanges heat with the flue gas countercurrently in the flue gas-molten salt heat exchanger 4, and is used to absorb the waste heat of the flue gas Then continue to be sent to the smoke temperature stabilizer 5 to exchange heat with the flue gas downstream to stabilize the temperature of the flue gas; the molten salt that is further heated after absorbing heat is sent back to the high-temperature molten salt tank 1 to reduce the temperature in the tank Unevenness of distribution.

(4) In the smoke temperature stabilizer 5, part of the molten salt flows back into the inlet through the bypass pipe from the outlet to adjust the molten salt flow rate to stabilize the flue gas temperature and prolong the residence time of the flue gas in the temperature range above 850°C for at least 5 seconds to promote the decomposition of organic matter including dioxins;

In this method, the temperature of the molten salt in the high-temperature molten salt tank 1 and the low-temperature molten salt tank 2 is controlled to be 850±20°C and 600±15°C respectively; the temperature of the molten salt at the inlet of the smoke temperature stabilizer 5 is 800±10°C , the temperature of the molten salt at the outlet is 850±10°C; the temperature of the molten salt at the outlet of the flue gas-molten salt heat exchanger 4, molten salt-steam reheater 3 and electric heater 6 is respectively related to the molten salt at the corresponding arrival position Salt temperature remains consistent. The external heat exchange medium of the flue gas temperature stabilizer 5 is the flue gas at the outlet of the incinerator, the temperature at the inlet side is 950±50°C, and the temperature at the outlet side is 850±10°C; the external heat exchange of the flue gas-molten salt heat exchanger 4 The medium is the flue gas from the outlet of the flue temperature stabilizer 5, the temperature of the inlet side is 850±10°C, and the temperature of the outlet side is 650±15°C; the temperature of the tube wall of the electric heater 6 is 950±50°C; On the steam side of the steam reheater 3, the steam parameters at the inlet are 0.6MPa and 248°C, and the steam parameters at the outlet are 3.82MPa and 435°C.

Use the valves configured in the system to control the flow of molten salt entering the flue gas-molten salt heat exchanger 4, molten salt-steam reheater 3, electric heater 6 and flue temperature stabilizer 5 bypass pipeline. Among them, the molten salt flow rate of the flue gas-molten salt heat exchanger 4 is adjusted according to the molten salt temperature at the outlet side; the molten salt flow rate of the molten salt-steam reheater 3 is adjusted according to the steam temperature at the outlet side; The salt flow rate is adjusted according to the molten salt temperature at the outlet side; the molten salt flow rate in the bypass line of the flue temperature stabilizer 5 is adjusted according to the flue gas temperature at the outlet side.

Concrete application examples:

Choose a waste incineration power plant in Zhejiang, and install various equipment, pumps, valves and pipelines in its power generation device using traditional technology as shown in Figures 1 and 2. The outer sides of the high-temperature molten salt tank 1 and the low-temperature molten salt tank 2 are equipped with a fully-enclosed or half-enclosed electric heating module, which is used when the machine is shut down, or the temperature of the molten salt is too low (the temperature of the high-temperature molten salt is lower than 835°C, the temperature of the low-temperature When the molten salt is lower than 585°C), the molten salt is heated. Fill the high-temperature molten salt tank 1 and the low-temperature molten salt tank 2 with the ternary eutectic chloride salt of NaCl-KCl- _CaCl2 as the internal heat exchange medium, the melting point of which is 543°C, 1.01×10 ⁵ Pa, 5h at 850°C The mass loss was 4%. Then turn on the heating to melt the molten salt, and perform equipment testing after exhausting, ready to be put into operation.

The flue gas at the furnace outlet of the incinerator flows through the flue gas temperature stabilizer 5 and the flue gas-molten salt heat exchanger 4 in sequence, then continues to pass through other heat exchangers such as the superheater, economizer, and air preheater, and finally enters the exhaust gas purification system . The high-temperature molten salt is extracted from the high-temperature molten salt tank 1 and sent to the molten salt-steam reheater 3 . The steam from the steam turbine is heated by the molten salt-steam reheater 3, and the temperature and pressure are increased, and then it is used as high-pressure steam and then returned to the steam turbine to release heat and perform work. After the molten salt is extracted from the low-temperature molten salt tank 2, it flows through the flue gas-molten salt heat exchanger 4 and the flue temperature stabilizer 5 in sequence, and returns to the high-temperature molten salt tank 1 after absorbing the heat of the flue gas respectively, for preservation and lowering of the temperature in the tank. Inhomogeneity of molten salt temperature. Use the flue gas temperature stabilizer 5 to prolong the residence time of the flue gas in the high temperature area, ensure that the residence time of the flue gas above 850°C is at least 5s, and promote the pyrolysis of dioxins and other organic substances. The low-temperature molten salt is extracted from the low-temperature molten salt tank 2 and sent to the electric heater 6 to absorb heat, and then sent to the high-temperature molten salt tank 1 .

Table 1 shows the heat transfer medium parameters of each equipment. The molten salt flows of the high-temperature molten salt pump 7 , the first low-temperature molten salt pump 8 and the second low-temperature molten salt pump 9 are respectively controlled by corresponding valves, and the adjustment amount is controlled according to the medium temperature feedback. Among them, the feedback parameter of the flue gas temperature stabilizer 5 and the flue gas-molten salt heat exchanger 4 is the flue gas side outlet temperature, the feedback parameter of the electric heater 6 is the molten salt temperature at the outlet end, and the molten salt-steam reheater 3 The feedback parameter is the steam outlet side temperature.

Table 1 Equipment heat transfer medium parameters

This embodiment is based on the transformation of a waste incineration power plant with traditional technology. The daily power generation of the original device is 1.2 million kWh, and the peak-shaving capacity after transformation is 25%. The molten salt heat storage material used is NaCl-KCl-CaCl ₂ , 50-30-20wt.%. The thermoelectric conversion rate of the salt exothermic process reaches 78%. In addition, compared with before transformation, the emission of dioxins decreased from 0.0670ng I-TEQ/Nm ³ to 0.0047ngI-TEQ/Nm ³ , a decrease of 30%. It can be seen that the present invention can indeed solve technical problems and obtain corresponding technical effects in practical applications.

The above are specific embodiments of the present invention. Obviously, those skilled in the art can make subsequent various applications, supplements, changes and modifications to the present invention without departing from the spirit and scope of the present invention. If various applications, supplements, modifications and variations based on the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention also intends to include these applications, supplements, modifications and variations.

Claims (10)

1. The electric power consumption system of the waste incineration power plant based on the regenerated salt heat storage of the incineration fly ash is characterized by comprising a high-temperature salt melting tank and a low-temperature salt melting tank which are arranged in the waste incineration power plant, and a smoke temperature stabilizer, a smoke-fused salt heat exchanger, a fused salt-steam reheater and an electric heater which are used as heat exchange equipment; wherein,,

the flue gas temperature stabilizer and the flue gas-molten salt heat exchanger are sequentially arranged in a flue behind the incinerator along the flue gas flow direction, and both take flue gas as an external heat exchange medium and molten salt as an internal heat exchange medium; the internal heat exchange medium of the fused salt-steam reheater is fused salt, the external heat exchange medium is steam from an extraction opening of a steam turbine, and the steam turbine is connected with a generator set of the waste incineration power plant; the fused salt is regenerated salt obtained by water washing, salt leaching and evaporative crystallization of waste incineration fly ash, and has a melting point of less than or equal to 550 ℃ and 1.01X10 ⁵ 5h mass loss at Pa and 850 ℃<5, the heat storage operation requirement within the temperature range of 600-850 ℃ can be met;

the molten salt outlet arranged at the top of the high-temperature molten salt tank is sequentially connected with a molten salt pump, a molten salt-steam reheater and a molten salt inlet at the top of the low-temperature molten salt tank through pipelines; two molten salt outlets are arranged at the bottom of the low-temperature molten salt tank, one outlet is sequentially connected with a molten salt pump, a flue gas-molten salt heat exchanger, a flue gas temperature stabilizer and a molten salt inlet at the bottom of the high-temperature molten salt tank through pipelines, and the other outlet is sequentially connected with the molten salt pump, an electric heater and the molten salt inlet at the bottom of the high-temperature molten salt tank through pipelines.

2. The system of claim 1, wherein the bodies of the high temperature molten salt tank and the low temperature molten salt tank are cylinders having a sealed structure, and an electric heating module is disposed around the outside of the cylinders.

3. The system of claim 1, wherein all of the consumers in the system are connected to a power supply system of the waste incineration power plant by cables to achieve self-power generation.

4. The system of claim 1, wherein the electric heater is further connected to an external power source via a cable, the external power source being a wind power plant, a photovoltaic power plant, a hydro power plant, or a utility grid.

5. The system of claim 1, wherein in the flue gas-molten salt heat exchanger, the flue gas is arranged counter-currently to the molten salt; in the molten salt-steam reheater, the molten salt is arranged in countercurrent with steam; in the smoke temperature stabilizer, the smoke and molten salt are arranged in parallel flow; a bypass pipeline is arranged between the molten salt inlet and outlet of the smoke temperature stabilizer.

6. A method for implementing electric power consumption in a waste incineration plant using the system according to claim 1, comprising:

(1) The flue gas at the outlet of the incinerator hearth of the garbage incineration power plant sequentially flows through a flue gas temperature stabilizer and a flue gas-molten salt heat exchanger, and enters a tail gas purification system after exchanging heat with molten salt in the flue gas temperature stabilizer and the flue gas-molten salt heat exchanger;

(2) The steam from the steam extraction port of the steam turbine enters a fused salt-steam reheater to exchange heat with fused salt extracted from a high-temperature fused salt tank, and the warmed steam is sent back to the steam turbine to release heat and do work for power generation; the molten salt after cooling is sent into a low-temperature molten salt tank;

(3) Pumping molten salt from the low-temperature molten salt tank, and respectively sending the molten salt to an electric heater and a flue gas-molten salt heat exchanger; the molten salt is heated in the electric heater for consuming the power allowance of the power plant or external power supply; the molten salt exchanges heat with the flue gas in a flue gas-molten salt heat exchanger in a countercurrent way, and is used for absorbing the waste heat of the flue gas; then continuously sending the mixture into a smoke temperature stabilizer 5 to exchange heat with smoke in concurrent flow for stabilizing the temperature of the smoke; the molten salt which is heated further after absorbing heat is sent back to the high-temperature molten salt tank for reducing the non-uniformity of temperature distribution in the tank;

(4) In the flue gas temperature stabilizer, part of molten salt flows back to the inflow port from the outlet through the bypass pipe, and is used for adjusting the flow rate of the molten salt to stabilize the temperature of flue gas, so that the residence time of the flue gas in a temperature region above 850 ℃ is prolonged to at least 5 seconds, and the decomposition of organic matters including dioxin is promoted.

7. The method of claim 6, wherein the molten salt temperatures in the high temperature molten salt tank and the low temperature molten salt tank are controlled to be 850±20 ℃ and 600±15 ℃, respectively; the temperature of molten salt at the inlet of the smoke temperature stabilizer is 800+/-10 ℃, and the temperature of molten salt at the outlet of the smoke temperature stabilizer is 850+/-10 ℃; the molten salt temperatures at the outlets of the flue gas-molten salt heat exchanger, the molten salt-steam reheater and the electric heater are respectively consistent with the molten salt temperatures at the corresponding reaching positions.

8. The method according to claim 6, wherein the external heat exchange medium of the flue gas temperature stabilizer is flue gas at the outlet of the furnace chamber of the incinerator, and the temperature of the inlet side is 950+/-50 ℃ and the temperature of the outlet side is 850+/-10 ℃; the external heat exchange medium of the flue gas-molten salt heat exchanger is flue gas from the outlet of the flue gas temperature stabilizer, the temperature of the inlet side of the flue gas-molten salt heat exchanger is 850+/-10 ℃, and the temperature of the outlet side of the flue gas-molten salt heat exchanger is 650+/-15 ℃; the temperature of the pipe wall of the electric heater is 950+/-50 ℃; on the steam side of the molten salt-steam reheater, the steam parameters at the inlet are 0.6MPa and 248 ℃, and the steam parameters at the outlet are 3.82MPa and 435 ℃.

9. The method of claim 6, wherein the flow of molten salt into the flue gas-molten salt heat exchanger, the molten salt-steam reheater, the electric heater and the flue gas temperature stabilizer bypass line is controlled by a valve; the flow of molten salt of the flue gas-molten salt heat exchanger is regulated according to the temperature of the molten salt at the outlet side; the molten salt flow of the molten salt-steam reheater is adjusted according to the steam temperature at the outlet side; the molten salt flow of the electric heater is regulated according to the molten salt temperature at the outlet side; and the molten salt flow of the bypass pipeline of the smoke temperature stabilizer is regulated according to the smoke temperature at the outlet side.

10. The system of claim 6, wherein the molten salt is regenerated salt produced by evaporation and crystallization after salt elution of fly ash water from garbage incineration, and the components are NaCl, KCl and CaCl ₂ Is a ternary eutectic chloride salt of (2); the melting point of the ternary eutectic chloride salt is less than or equal to 550 ℃ and is 1.01X10 ⁵ 5h mass loss at Pa and 850 ℃<5％。