CN104006540B - Heat chemistry energy storage testing arrangement and method of testing - Google Patents

Abstract

The invention discloses a thermochemical energy storage test device and a test method. The test device includes a solar heat collector, a heat storage tank, an energy storage reactor, an energy release reactor, a cold storage tank, a condenser, an evaporator, a circulation pump and an automatic temperature control system. control device. The outlet pipe of the solar collector is connected to the inlet of the heat storage tank, and the high-temperature heat transfer fluid flows into the energy storage reactor from the outlet pipe at the bottom of the heat storage tank, and enters the CaO/Ca(OH) ₂ particle bed wrapped in a stainless steel mesh tube. The heat exchange coil, the outlet of the heat exchange coil is connected to the cold storage tank, and the circulation pump is located between the outlet pipe of the cold storage tank and the inlet pipe of the solar collector. The device can effectively use solar energy to drive thermochemical energy storage reactions, realize solar thermal energy storage and chemical energy release, and test the energy storage/release rate. The invention has the advantages of high energy storage density, high energy quality, simple test operation, low cost and easy storage of decomposition products.

Description

Thermochemical energy storage test device and test method

technical field

The technical field of chemical energy storage of the present invention, specifically relates to a thermochemical energy storage testing device and testing device that fully utilizes solar energy to drive (Ca(OH) ₂ (s)↔CaO (s)+H ₂ O (g)) thermochemical reaction method.

Background technique

With the rapid development of society, the limited fossil fuels are becoming more and more scarce, which cannot meet the needs of modern industrial development, and the environmental problems caused by combustion are becoming increasingly prominent. The new direction of energy structure reform is mainly to develop new energy sources and adopt new technologies to improve fuel utilization. Solar power generation has become an ideal alternative energy source due to its advantages of low cost, wide sources, no pollution to the environment, and no need for long-distance transmission. Vigorously developing and utilizing solar energy will effectively alleviate the problem of energy shortage, change my country's irrational energy structure, and diversify energy supply. However, due to the intermittent, low density and instability of solar energy, which makes it difficult to supply continuously, there are still many problems to be solved in the use of solar energy for thermal power generation. Among them, how to achieve efficient and large-scale storage of solar energy to ensure continuous solar energy 24 hours a day Supply is the key to solar thermal power technology. In solar thermal power generation, the role of high-temperature heat storage is to adjust the load, reduce equipment capacity and investment costs, further improve the utilization efficiency of solar resources and equipment availability, and improve the reliability and economy of thermal power systems. At present, the main thermal energy storage methods include sensible heat energy storage, latent heat energy storage and thermochemical energy storage. Many factors need to be considered when choosing an energy storage method, mainly including storage time, economy, energy storage density, heat loss, energy supply temperature, etc.

Sensible heat storage refers to energy storage by changing the temperature of the energy storage medium. The energy storage materials can be water, rock, soil, etc. The method is simple and the cost is low, but the energy storage density is small and the heat release temperature is not constant, and the required energy storage system structure is huge. Latent heat energy storage, also known as phase change energy storage, is a research hotspot in the world today, such as water heating to gasification, solid paraffin heating to melting, etc. The energy storage density of latent heat energy storage is an order of magnitude higher than sensible heat, and the heat release temperature is constant, but its heat storage medium generally has disadvantages such as low thermal conductivity, easy aging, and supercooled phase separation. Sensible heat energy storage and latent heat energy storage both have the disadvantage of excessive heat loss at high temperature, and cannot store high temperature heat energy for a long time.

Chemical energy storage is actually to release the stored chemical energy by using the chemical reaction that occurs when the energy storage materials are in contact. Such as C + heat ↔ A + B, in this reaction, the energy storage material C absorbs energy and converts it into A and B for separate storage. When energy needs to be supplied, A and B are fully contacted to react to generate C, and the energy release process is also completed. Generally, the thermochemical energy storage process can be divided into three steps: heat storage, storage, and heat release process.

Compared with other heat storage methods, thermochemical energy storage has the following advantages: (1) thermochemical energy storage method can realize long-term storage without heat loss at room temperature; (2) high energy storage density, which is equivalent to sensible heat storage and 10 times and 5 times of latent heat storage; (3) Suitable for long-distance transportation. These characteristics provide a promising method for the efficient conversion, storage and transmission of solar energy, and can realize the continuous supply of solar energy 24 hours a day, especially suitable for peak and valley load regulation of power plants, and release heat energy during peak power generation, promoting Steam turbines generate electricity. At present, more than 70 thermochemical reactions have been studied, but there are not many ideal reaction systems. Typical thermochemical energy storage systems include the thermal decomposition of inorganic hydroxides, mainly Ca(OH) ₂ /CaO+H ₂ O, Mg(OH) ₂ /MgO+H ₂ O, in addition to the decomposition of NH ₃ , carbonic acid Decomposition of compounds, decomposition of sulfate, catalytic reforming of methane-carbon dioxide, thermal decomposition of ammonium salts, hydrogenation and dehydrogenation of organic matter, etc. Among them, the decomposition of Ca(OH) ₂ /CaO system and NH ₃ is more researched energy storage Reaction is also the most promising application for energy storage systems. The following factors should be considered when selecting chemical energy storage materials: (1) the reaction temperature is appropriate; (2) the thermal effect of the reaction is large; (3) the reaction does not produce side reactions, is safe, and has a long cycle life; (4) the energy storage material is cheap and has no (5) The volume change of the material during the reaction should be small; (6) The reversible chemical reaction rate should be appropriate to facilitate energy storage and release; (7) The reaction operation is mature and the reaction conditions are not harsh.

The increasing energy shortage worldwide, the environmental pollution caused by the burning of fossil fuels, and my country's current energy structure adjustment strategy have brought great opportunities for the application of thermochemical energy storage. Due to its unique Advantages, it has broad application prospects in the fields of large-scale gigawatt-level power peak regulation, solar thermal power generation, industrial and civil waste heat and waste heat recovery and utilization.

Thermochemical energy storage is a high-density, high-energy energy storage method. Its energy storage density is higher than sensible heat and latent heat, and this energy storage system is very easy to use for long-term energy storage through catalysts or product separation methods, but in When practical, there are disadvantages such as large one-time investment, complex technology and low overall efficiency. At present, thermochemical energy storage solar thermal power generation is still in the small-scale test stage, and large-scale thermal power plants have not yet been built. To make thermochemical energy storage truly a practical technology for the benefit of mankind, the following problems must be solved: (1) Energy storage Selection of materials, incidental reaction control, reversibility of reaction, catalyst life; (2) design of reactors and heat exchangers, characteristics of various chemical beds, thermal conductivity of gases, solids and other media; (3) operation Cycle description, optimal cycle efficiency; (4) technical and economic analysis, investment/revenue research, load requirements, etc.; (5) energy storage material corrosiveness and economy.

Contents of the invention

The present invention aims at the technical problems existing in the practical application of solar thermochemical energy storage, and provides a thermochemical energy storage testing device and testing method, which can convert solar energy into chemical energy and store it and release it in time when needed. The specific scheme is as follows.

Thermochemical energy storage test device, which includes: solar collector, temperature controller TC, temperature measurement transmitter TT, thermal storage tank, energy storage reactor, heat exchange coil, pressure gauge, thermocouple thermometer, condenser , heat exchanger, resistance wire heater, cold storage tank and circulating pump; the temperature measuring transmitter TT is used to measure the temperature of the outlet fluid of the solar collector, and the temperature controller TC is used to control the inlet pipe of the solar collector The opening degree of the first valve V1 on the road, the temperature controller TC and the temperature measuring transmitter TT form an automatic temperature control device; the outlet pipe of the solar collector is connected to the inlet of the thermal storage tank, and the thermal fluid enters through the outlet pipe at the bottom of the thermal storage tank The heat exchange coil inside the energy storage reactor; the first thermocouple thermometer is installed in the energy storage reactor, the steam outlet pipe on the top of the energy storage reactor is connected to the condenser, and the liquid level sensor, resistance wire A heater, a second thermocouple thermometer and a heat exchanger; the outlet pipe of the energy release reactor is connected to the cold storage tank, and the circulation pump is installed between the outlet pipe of the cold storage tank and the inlet pipe of the solar heat collector.

Further optimized, the interior of the energy storage reactor is wrapped with CaO/Ca(OH) ₂ stainless steel mesh tubes of the granular bed, the heat exchange coil is located at the center of the CaO/Ca(OH) ₂ granular bed, and the CaO/ The Ca(OH) ₂ particle bed is provided with 8 first thermocouple thermometers; the energy storage reactor is used as an energy release reaction during the hydration reaction of the CaO/Ca(OH) ₂ particle bed The internal structure of the energy release reactor is the same as that of the energy storage reactor, and the exterior of the energy storage reactor and the energy release reactor is wrapped with an insulating layer.

Further optimized, the solar collector is composed of glass casing, stainless steel outer wall, heat insulation layer and heat-absorbing coil. The heat-absorbing coil is arranged inside the glass casing, and the outer wall of the heat-absorbing coil is coated with selective coating. A glass-encased stainless steel exterior wraps around the insulation.

In order to overcome the instability of solar radiation, an automatic temperature control device is installed at the outlet of the solar collector, which is composed of a temperature controller TC and a temperature measurement transmitter TT; where the temperature measurement transmitter TT measures the outlet of the solar collector The temperature of the fluid, the temperature controller TC controls the opening of the first valve V1 on the inlet pipeline of the solar collector, and controls the temperature of the outlet fluid of the solar collector to be in a constant state by adjusting the flow rate of the stream 1.

Further optimization, the stainless steel mesh tube inside the energy storage reactor is divided into four parts by four copper fins arranged in pairs at 90 degrees. Each part is equipped with 3 stainless steel plates at equal intervals from top to bottom, and the whole stainless steel The grid cylinder is divided into 4×4, that is, 16 small areas; there are 8 first thermocouple thermometers, which are distributed in the relative 8 small areas in the CaO/Ca(OH) ₂ particle bed.

Further optimization, the bottom of the condenser is equipped with a resistance wire heater, so the condenser is used as an evaporator; the resistance wire heater is located at the bottom of the condenser, and the second thermocouple thermometer is used to measure the condensed water inside the condenser or the water inside the evaporator The temperature of the steam, the condenser and the evaporator are wrapped with a thermal insulation layer, and the cold water can flow into the evaporator through the inlet pipe through the fifth valve located at the bottom of the evaporator.

Further optimized, the cold fluid at the outlet of the heat exchange coil flows into the cold storage tank through the seventh valve.

The energy storage test method of the above thermochemical energy storage test device is specifically: hot water flows into the energy storage reactor from the outlet pipe at the bottom of the thermal storage tank, and transfers heat to the CaO/Ca(OH) ₂ particle bed to drive the thermochemical reaction (Ca(OH) ₂ (s)↔CaO(s)+H ₂ O(g)) occurs, the absorbed solar energy is converted into CaO and the chemical energy of water vapor is stored, and the water vapor is condensed by the condenser to form liquid water and CaO Automatic separate storage; when the water vapor enters the energy release reactor again, a hydration reaction occurs when it contacts with CaO and a large amount of heat is released, realizing the release process of chemical energy; the thermoelectricity in the CaO/Ca(OH) ₂ particle bed The dual thermometer shows the temperature at different positions in the bed, records the temperature at each moment, and obtains the energy storage and energy release rate according to the heat release rate.

The hot fluid enters the heat storage tank from the outlet of the solar collector for temporary storage, and then flows into the heat exchange coil in the storage reactor through the second valve V2 from the outlet pipe at the bottom of the heat storage tank, and the cold fluid after heat exchange flows from the energy storage The outlet pipe at the bottom of the reactor flows into the cold storage tank through the seventh valve V7 for temporary storage. The circulation pump is located between the outlet pipe of the cold storage tank and the inlet pipe of the solar collector, and is used to realize the circulation of the heat exchange fluid in the process of heat storage and heat release.

The top outlet pipe on the right side of the energy storage reactor is connected to the condenser, and the bottom outlet pipe of the energy storage reactor is connected to the inlet of the cold storage tank through the seventh valve V7. When an exothermic reaction occurs, the low-temperature heat transfer fluid can flow into the heat exchange coil from the bottom inlet pipe of the energy release reactor through the sixth valve V6, and the high-temperature heat transfer fluid after heat exchange flows out from the top outlet pipe through the third valve V3 .

Compared with the prior art, the present invention has the following advantages:

Can make full use of solar energy to drive chemical reactions (Ca(OH) ₂ (s)↔CaO(s)+H ₂ O(g), and the water vapor released by Ca(OH) ₂ during energy storage is permeable The stainless steel mesh enters the energy storage reactor, and enters the condenser along the steam outlet pipe at the top of the energy storage reactor to condense into liquid water, realizing the automatic separate storage of water vapor and solid CaO. When energy supply is required, external The waste heat is heated by the condensed water heat exchange in the heat exchanger and the condenser or the resistance wire heater at the bottom of the heater to heat the liquid water to generate water vapor. The water vapor enters the energy release reactor and re-contacts with solid CaO to react, and the released A large amount of heat can be collected by the heat exchange coil at the center of the CaO/ _Ca (OH) particle bed. Because the CaO/ _Ca (OH) particle bed has the defect of poor thermal performance, the entire CaO/Ca( OH) The ₂ particle bed is divided into 16 small areas with 4 copper fins and three stainless steel plates. An automatic temperature control device is installed on the outlet pipeline of the solar collector, and the solar collector is controlled by adjusting the fluid flow rate at the outlet of the cold storage tank. Heater outlet fluid temperature. This device can effectively realize the conversion of solar energy into chemical energy, and it is a solid-gas reaction. The storage and transportation of the energy storage medium are simple, and it has the advantages of easy control, high energy utilization efficiency, and high energy storage density.

Description of drawings

Figure 1 is an overall schematic diagram of a thermochemical energy storage device.

Figure 2 is a diagram of the internal structure of the energy storage reactor.

Fig. 3 is the arrangement diagram of the thermocouple thermometer in the CaO/Ca(OH) ₂ particle bed.

Figure 4 is a front view of the solar collector.

Figure 5 is a side view of the solar collector.

detailed description

The structure and specific working process of the present invention will be described in detail below in conjunction with the accompanying drawings, but the implementation and protection of the present invention are not limited thereto.

As shown in Figure 1, the thermochemical energy storage test device includes a solar collector 1, a first valve V1 2, a temperature controller TC 3, a temperature measurement transmitter TT 4, a heat storage tank 5, an energy storage reactor 6, a heat exchanger Heat coil 7, pressure gauge 11, energy release reactor 13, first thermocouple thermometer 15, condenser 17, evaporator 20, heat exchanger 21, resistance wire heater 22, cold storage tank 23, circulation pump 24. As shown in FIG. 4 and FIG. 5 , the solar heat collector 1 is mainly composed of a glass envelope 25 and a heat-absorbing coil 28 with good thermal conductivity. The thermal fluid at the outlet of the solar collector 1 flows into the thermal storage tank 5 for temporary storage, and the thermal fluid enters the heat exchange coil 7 inside the energy storage reactor 6 through the second valve V2 through the outlet pipe of the thermal storage tank 5 . The automatic temperature control device is composed of a temperature controller TC 3 and a temperature measuring transmitter TT 4. The temperature controller TC 3 can control the opening of the first valve V1 on the inlet pipeline of the solar collector, by adjusting the flow of the stream 1 rate to control the outlet fluid temperature of the solar collector in a constant state.

A pressure gauge 11 is installed on the top of the energy storage reactor 6 . As shown in Figure 2, the interior of the energy storage reactor 6 is a stainless steel mesh cylinder 12 wrapped with a CaO/Ca(OH) ₂ particle bed 9, and four copper fins 8 are arranged adjacent to each other at 90 degrees to connect the stainless steel mesh cylinder ₁₂ is equally divided into four parts, and each part is provided with three stainless steel plates 10 at equal intervals from top to bottom, as shown in Fig. area. The heat exchange coil 7 is located at the center of the CaO/Ca(OH) ₂ particle bed 9, and the cold fluid flows into the cold storage tank 23 through the seventh valve V7 through the heat exchange coil. The 8 first thermocouple thermometers 15 are respectively arranged in 8 small areas in the opposite corner positions in the CaO/Ca(OH) ₂ particle bed. The circulation pump 24 is located between the outlet pipeline of the cold storage tank 23 and the inlet pipeline of the solar heat collector 1 . The steam outlet pipe at the top of the energy storage reactor 6 is connected to the condenser 17, the liquid level sensor 16, the heat exchanger 21 and the second thermocouple thermometer 18 are arranged in the condenser 17, and the resistance wire heater 22 is arranged in the evaporator 20.

The top of the energy storage reactor 6 is connected to the steam outlet pipe, and the fourth valve V4 is opened. The water vapor enters the condenser 17 and is condensed into liquid water for storage. The pressure gauge at the top can monitor the pressure in the container at any time, and the second valve installed at the bottom The thermocouple thermometer 18 can monitor the temperature of the condensed water in the condenser 17 or the water vapor in the evaporator 20 . The liquid level change in the condenser 17 or the heater 20 can be read through the liquid level sensor 16, and a resistance wire heater 22 is installed at the bottom of the evaporator, and cold water can also be added to the evaporator 20 through the fifth valve V5.

The specific usage of this device is as follows: Solar thermal energy storage process: After being heated, the low-temperature heat transfer fluid flows into the heat storage tank 5 with good thermal insulation performance through the outlet pipe of the solar collector for storage. pressure. Open the second valve V2 on the outlet pipeline at the bottom of the thermal storage tank, and the thermal fluid flows into the energy storage reactor 6 in the CaO/Ca(OH) heat exchange coil ₇ at the center of the particle bed, and transfers heat to CaO/Ca ( OH) ₂ particle bed, Ca(OH) ₂ is thermally decomposed to generate CaO and water vapor, realizing the chemical energy storage of solar energy with CaO and water vapor. According to the reading of the first thermocouple thermometer 15 in the CaO/ _Ca (OH) particle bed and the temperature (510° C.) of _Ca (OH) thermal decomposition, it can be inferred whether the decomposition reaction occurs, that is, whether the energy storage process occurs, according to The rate of energy storage can be calculated from the speed at which the thermocouple thermometer reading changes. Open the seventh valve V7, keep the sixth valve V6 closed, the low-temperature heat transfer fluid flows into the cold storage tank 23 for storage, and the circulation pump 24 pumps the cold fluid into the solar collector 1 again to start the next heat storage cycle. According to the reading of the temperature measuring transmitter, the opening degree of the first valve V1 is automatically adjusted through the temperature controller to keep the temperature of the fluid at the outlet of the solar collector constant.

Storage and separation process of energy storage medium: the water vapor generated in the reaction process flows out through the stainless steel mesh 12 along the steam outlet pipe at the top of the energy storage reactor. Open the fourth valve V4. The water vapor flows into the condenser 17 through the steam outlet pipe at the top of the energy storage reactor and condenses to become liquid water, which is automatically stored separately from solid CaO. The pressure gauge and liquid level sensor can display the water vapor in the condenser. pressure and level.

The heat release process of chemical energy: the external waste heat can be used to exchange heat between the heat exchanger 21 and the condensed water in the condenser to generate water vapor, and the resistance wire heater 22 in the evaporator 20 can also be used to generate water vapor. Open the fourth valve V4, water vapor enters into the energy release reactor 13 along the pipeline, and reacts with the CaO inside the stainless steel mesh cylinder 12 to generate Ca(OH) ₂ while releasing a large amount of heat, while maintaining the second valve V2 and The seventh valve V7 is closed, allowing the cold fluid to flow into the heat exchange coil 7 in the energy release reactor through the sixth valve V6, and the hot fluid after heat exchange flows out through the third valve V3 for use, thereby realizing the release of chemical energy. When the reading of the thermocouple thermometer in the CaO/Ca(OH) ₂ particle bed begins to rise continuously, it means that the heat release process of chemical energy has occurred, and the heat release rate can be calculated according to the speed of the bed temperature rise.

Claims (4)

1. heat chemistry energy storage testing arrangement, it is characterized in that, comprising: solar thermal collector (1), temperature controller TC (3), temperature survey transmitter TT (4), hot tank (5), energy storage reactor (6), heat exchange coil (7), Pressure gauge (11), the first thermocouple thermometer (15), condenser (17), heat exchanger (21), resistance heater (22), cold storage tank (23) and circulating pump (24); Wherein temperature survey transmitter TT (4) is for measuring the temperature of solar thermal collector (1) outlet fluid, the aperture of temperature controller TC (3) first valve V1 (2) on the entrance pipe controlling solar thermal collector (1), temperature controller TC (3) and temperature survey transmitter TT (4) forms thermostat; The outlet of solar thermal collector (1) connects the import of hot tank (5), and hot fluid enters the inner heat exchange coil (7) of energy storage reactor (6) through hot tank (5) outlet at bottom pipe; The first thermocouple thermometer (15) is provided with in energy storage reactor (6), energy storage reactor (6) overhead vapor outlet is connected to condenser (17), is provided with level sensing meter (16), resistance heater (22), the second thermocouple thermometer (18) and heat exchanger (21) in condenser (17); Exoenergic reaction device (13) outlet connects cold storage tank (23), and circulating pump (24) is arranged between the inlet ductwork of cold storage tank (23) outlet and solar thermal collector (1);

Described energy storage reactor (6) inside is wrapped in CaO/Ca (OH) ₂the stainless (steel) wire cylinder (11) of particle layers (9), heat exchange coil (7) is positioned at CaO/Ca (OH) ₂the center of particle layers (9), CaO/Ca (OH) ₂8 described first thermocouple thermometers (15) are provided with in particle layers (9); Described energy storage reactor (6) is at CaO/Ca (OH) ₂particle layers (9) occurs to be used as exoenergic reaction device (13) again in the process of hydration reaction, the Inner Constitution of exoenergic reaction device (13) is with described energy storage reactor (6), and energy storage reactor (6) and exoenergic reaction device (13) outer wrap have heat insulation layer (14);

Condenser (17) bottom is provided with resistance heater, therefore condenser (17) is again as evaporimeter (20); Resistance heater (22) is positioned at the bottom of condenser (17), second thermocouple thermometer (18) is for measuring the temperature of condenser (17) internal condensation water or evaporimeter (20) internal water steam, the outer wrap of described condenser (17) and evaporimeter (20) has heat insulation layer (19), and cold water can flow into evaporimeter (20) by the 5th valve (V5) being positioned at evaporimeter (20) bottom through inlet tube.

2. heat chemistry energy storage testing arrangement according to claim 1, it is characterized in that, solar thermal collector (1) is made up of glass sleeve (25), stainless steel outer wall (26), heat insulation layer (27) and heat absorption coil pipe (28), heat absorption coil pipe (28) is arranged in the inside of glass sleeve (25), heat absorption coil pipe (28) outer wall scribbles selective coating, and the stainless steel outer wall (26) of glass sleeve is wrapped in heat insulation layer (27).

3. heat chemistry energy storage testing arrangement according to claim 1 and 2, it is characterized in that, the stainless (steel) wire cylinder (11) of energy storage reactor (6) inside is divided into four parts in 90 degree of layouts between two by four copper fins (8), each part is spaced set 3 pieces of corrosion resistant plates (10) from top to bottom, whole stainless (steel) wire cylinder (11) are divided into 4 × 4 i.e. 16 zonules; Described first thermocouple thermometer (15) has 8, is distributed in CaO/Ca (OH) ₂the inside, 8 zonules of vertical angles is become in particle layers (9).

4. utilize the energy storage method of testing of the heat chemistry energy storage testing arrangement described in claim 1, it is characterized in that: hot water flows into energy storage reactor (6) from hot tank outlet at bottom pipe, and transfers heat to CaO/Ca (OH) ₂particle layers (9), drives thermal chemical reaction (Ca (OH) ₂(s) CaO (s)+H ₂o (g)) occur, the chemical energy that the solar energy of absorption is converted into CaO and steam stores, and steam forms aqueous water through condenser (17) condensation and CaO separately stores automatically; When steam enters into exoenergic reaction device (13) again, and there is hydration reaction when CaO contacts and release a large amount of heat, realizing the dispose procedure of chemical energy; CaO/Ca (OH) ₂thermocouple thermometer (15) in particle layers demonstrates diverse location place temperature in bed, records the temperature in each moment, and obtaining energy storage according to HRR and release can speed.