High-temperature thermochemical particle sampling system and sampling method

Abstract

The invention relates to the field of photo-thermal power generation, in particular to a high-temperature thermochemical particle sampling system and a particle sampling method. The system comprises a sampler, a stock bin, a vacuum generator, an inert atmosphere supply device, pipelines and valves, wherein the pipelines and the valves are arranged among all the components. Wherein the sampler is in direct contact with and absorbs a high-temperature thermochemical particle sample; the stock bin is arranged at the outlet of the sampler and is used for temporarily storing the sucked thermochemical particle sample; an inlet of the vacuum generator is connected with the stock bin and used for keeping the vacuum degree of the stock bin to provide suction force. The inert atmosphere supply device can provide inert atmosphere for the particle samples in each link; the valve can control the on-off state of a pipeline between devices in real time and is used for adjusting the flow direction of gas / solid media. By forming negative pressure to generate suction force and combining protection measures of inert atmosphere and cooperative operation of all pipeline valves, particles in different areas can be sampled in real time, and meanwhile, the problem of sample distortion caused by an oxidation process in a particle sampling process can be effectively avoided.

Description

Technical Field

[0001] The present invention relates to the field of solar thermal power generation, and particularly to a high-temperature thermochemical particle sampling system and a particle sampling method. Background Art

[0002] Currently, thermal oil and molten salt are mostly used as media in solar thermal power generation, and their working temperatures generally do not exceed 400°C and 565°C respectively. However, for the next-generation solar thermal power generation technology using particles as the medium, the working temperature can be increased to above 1000°C, which has the potential to improve the power generation efficiency and reduce the cost per kilowatt-hour. Compared with inert particles, selecting thermochemical particles as the medium can utilize their chemical reaction characteristics to further improve the heat storage density and heat collection stability.

[0003] However, there are problems such as the decay of physical and chemical properties of thermochemical particles during operation, which threaten the safe and stable operation of the system and require regular monitoring. In addition, the temperature of thermochemical particles remains basically unchanged during the reaction process, making it difficult to know the reaction progress by measuring the temperature, and thus it is difficult to fully utilize their chemical heat storage capacity. Therefore, it is necessary to obtain particle samples through methods such as mechanical sampling and vacuum sampling, and then conduct a detailed analysis of the samples. However, during the sampling process, the particle samples will rapidly cool down in an air atmosphere and are extremely prone to oxidation, resulting in sample distortion. In addition, the current sampling methods are mostly fixed-point sampling, that is, an opening valve is set at a specific position of the absorber. When sampling is required, the valve is opened, and then the sample at that place is taken out. This method is simple to operate, but it is difficult to know the particle state in other areas, and the sampling result has limitations, and there is still an oxidation risk for the particles.

[0004] Currently, most particle absorbers adopt an open structure, which provides conditions for real-time sampling technology without limited areas. If a system and method that can sample particles in different areas in real time can be designed, it will play a significant guiding role in the monitoring and control of the operating state of the absorber. Summary of the Invention

[0005] In view of the above problems, the present invention provides a high-temperature thermochemical particle sampling system and a sampling method. By forming a negative pressure to generate suction, combined with protective measures in an inert atmosphere and the coordinated operation of each pipeline valve, it can sample particles in different areas in real time, and at the same time can effectively avoid the problem of sample distortion caused by oxidation during the particle sampling process.

[0006] In the first aspect of the present invention, a high-temperature thermochemical particle sampling system is provided, which includes a sampler, a silo, a vacuum generator, an inert gas supply device, and pipelines and valves among various components. The sampler is used to obtain a thermochemical particle sample at the position to be sampled; the silo is connected to the sampler through a pipeline and is used to temporarily store the inhaled thermochemical particle sample and cool the thermochemical particle sample therein to below the oxidation temperature; the outlet of the vacuum generator is connected to the silo and is used to maintain the vacuum degree of the silo to provide suction; the inert gas supply device is connected to the sampler and the silo through pipelines and can provide an inert gas for the particle samples in each link; valves are provided on the pipelines between the sampler and the silo, the silo and the vacuum generator, and the silo and the inert gas supply device respectively, which are used to control the opening and closing of the pipelines where they are located, so as to adjust the flow direction of the gas / solid medium.

[0007] Optionally, the system further includes a sampling extension tube, and the sampler is arranged at the end of the sampling extension tube. The sampling extension tube can be made of a stainless steel flexible hose to increase the extension distance of the sampler and facilitate the sampler to sample at various parts of the heat absorption device.

[0008] Optionally, the surfaces of the sampler and the sampling extension tube that may be exposed to the internal environment of the heat absorber are coated with a high-reflectivity coating, which is used to reduce the absorption of incident light by them, so as to relieve the structural deformation caused by temperature rise.

[0009] Optionally, the sampler is of a tapered type to improve the sampling accuracy and reduce the inhalation of the surrounding oxidation atmosphere.

[0010] Optionally, the silo is also provided with a weighing device to measure the total weight of the silo and the particle sample therein in real time, so as to judge whether the sampling is successful and whether the sampling amount meets the standard; a flexible connection is adopted between the silo and the system pipeline.

[0011] Optionally, the silo is equipped with a cooling and temperature measuring unit all around. The cooling unit is used to maintain the low temperature state of the silo to ensure that the particle sample is quickly cooled in the silo, and the temperature measuring unit is used to monitor the sample temperature. When the particles drop below the set temperature, the material is unloaded in time. The set temperature must be at least lower than the oxidation reaction temperature to avoid oxidation reaction during the unloading process, resulting in sample distortion.

[0012] Optionally, the bottom of the silo is open and an electric valve is arranged at the opening. During sampling, the electric valve is closed to ensure the sealing state of the silo. After sampling is completed and the sample temperature drops to the set temperature, the electric valve is opened to enable the particle sample to leave the silo under the action of gravity.

[0013] Optionally, the system is provided with an openable and closable system exhaust port on the pipeline between the silo and the vacuum generator. When the system needs to exhaust, the system exhaust port is opened; alternatively, the vacuum generator is selected as a vacuum pump that is a passage by itself in the shutdown state, so that the vacuum pump can be used as the system exhaust port in the shutdown state of the system, eliminating the need to separately set up a system exhaust port.

[0014] Optionally, the vacuum generator is configured with a corresponding electronic control system to adjust its operation time and operation intensity.

[0015] Optionally, a filter screen is arranged between the vacuum generator and the silo to prevent particulate samples from being sucked into the vacuum generator; preferably, the filter screen is arranged above the top of the silo.

[0016] Optionally, when the vacuum generator is in a non-start state, its gas path is a passage, so that its exhaust port can be directly used as the system exhaust port without the need to separately set up an additional exhaust port.

[0017] Optionally, the inert gas supply device is provided with an outlet pressure regulating unit to control the outlet pressure and flow rate of the inert gas.

[0018] Optionally, the inert gas supply device can switch different inert gases to specifically provide inert gases for different types of thermochemical particles. For example, for metal oxide particles, carbon dioxide can be provided as the inert gas, but for carbonate particles, carbon dioxide is an oxidant instead, and in this case, an inert gas such as nitrogen should be switched to provide.

[0019] The second aspect of the present invention provides a method for sampling high-temperature thermochemical particles, which is applied to the above sampling system and includes the following steps:

[0020] Silo atmosphere inerting stage: Turn on the inert gas supply device, and open the valve between the inert gas supply device and the silo, as well as the valve between the silo and the exhaust port, so that the inert gas fills the silo and drives the originally air atmosphere filled in the silo to leave through the exhaust port;

[0021] Sample atmosphere inerting stage: Close the valve between the silo and the exhaust port, and open the valve between the sampler and the silo, so that the inert gas directly reaches the sampling area and dilutes the area near the sample to a nearly inert atmosphere;

[0022] Vacuum sampling stage: Open the valve between the silo and the vacuum generator, and turn on the vacuum generator, so that the inert gas from the inert gas supply device, the particulate sample, and a small amount of nearly inert atmosphere around the particulate sample are sucked into the silo together. Among them, the gas will further leave through the outlet of the vacuum generator, while the solid, that is, the particulate sample, will be left at the bottom of the silo;

[0023] Sample cooling stage: turn off the vacuum generator, close the valve between the silo and the sampler, open the valve between the silo and the exhaust port, allow the inert atmosphere to enter the silo, and continue to leave through the exhaust port to flush the particle samples in the silo, forcing the particles to quickly cool down to below the oxidation temperature in the inert atmosphere to avoid oxidation reaction;

[0024] Unloading stage: turn off the inert atmosphere supply device, close all valves at the same time, open the silo and take out the sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of a high-temperature thermochemical particle sampling system provided in an embodiment of the present invention.

[0026] Figure 2 It is a simplified structural diagram of a high-temperature thermochemical particle sampling system provided in an embodiment of the present invention.

[0027] Figure 3 It is a schematic flow chart of a high-temperature thermochemical particle sampling method provided in an embodiment of the present invention.

[0028] Figure markings: 100-high-temperature thermochemical particle sampling system, 1-sampler, 11-sampling extension tube, 12-particle heat absorption device (containing high-temperature thermochemical particles), 2-silo, 21-filter, 22-unloading silo, 23-cantilever beam force sensor, 3-vacuum generator, 31-vacuum pump, 32-electric control cabinet, 33-exhaust port, 4-inert atmosphere supply device, 41-barometer, V1-sampler pipeline control valve, V2-vacuum generator pipeline control valve, V21-unloading valve, V3-gas tank pipeline control valve, V4-pressure reducing valve. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] First embodiment

[0031] In order to achieve real-time and regionally flexible high-temperature thermochemical particle sampling functions, while avoiding the problem of sample distortion caused by oxidation during the sampling process as much as possible, this embodiment provides a high-temperature thermochemical particle sampling system 100. Figure 1 The high-temperature thermochemical particle sampling system 100 mainly includes a sampler 1, a silo 2, a vacuum generator 3 and an inert atmosphere supply device 4.

[0032] The sampler 1 is in direct contact with the inside of the particle heat absorption device 12 for obtaining the high-temperature thermochemical particles therein. In the present invention, the specific material of the high-temperature thermochemical particles is not limited, and any high-temperature thermochemical particles used in the solar thermal power generation technology are applicable to the present invention. These thermochemical particles basically maintain a constant temperature during the reaction process, and it is usually difficult to know the reaction process by measuring the temperature. In this embodiment, the high-temperature thermochemical particles are manganese sesquioxide. When the reduction reaction temperature is reached, manganese sesquioxide will gradually be reduced to manganese tetroxide. According to its reaction characteristics, during the reduction reaction process, the particle temperature basically remains unchanged.

[0033] The sampler 1 is placed at the end of the sampling extension tube 11 to increase its maximum sampling range; the sampler 1 and the sampling extension tube 11 are both made of high-temperature resistant stainless steel and are coated with a high-reflection coating on the surface to relieve their high-temperature deformation; a sampler pipeline control valve V1 is provided on the pipeline between the sampler 1 and the silo 2 to control the on-off of the gas / solid medium flow therebetween.

[0034] A vacuum generator pipeline control valve V2 is provided between the silo 2 and the vacuum generator 3 to control the on-off of the gas path of the pipeline therebetween; a filter screen 21 is also provided between the silo 2 and the vacuum generator 3 to prevent the particle sample from being sucked into the vacuum generator 3; a discharge bin 22 is arranged at the bottom of the silo 2, and a discharge valve V21 is provided between the silo 2 and the discharge bin 22 to facilitate the taking out and storage of the particle sample; a cantilever beam type force sensor 23 is also provided on the silo 2 to monitor the total weight of the silo 2 and the particle sample therein in real time, so as to judge the real-time sampling amount. For accurate weighing, the silo 2 and other components (including pipelines) must not be connected or soft connections are used. In a specific embodiment of the present invention, a soft connection is adopted between the silo 2 and the pipeline connecting the sampler, and the filter screen 21 is arranged above the top of the silo 2, and a soft connection is adopted between the filter screen 21 and the pipeline connecting the vacuum generator.

[0035] Preferably, the whole body of the silo is equipped with a cooling unit and a temperature measuring unit. The cooling unit is used to maintain the low-temperature state of the silo to ensure that the particle sample is quickly cooled in the silo, and the temperature measuring unit is used to monitor the sample temperature. When the particles are cooled below the set temperature, the material is unloaded in time, where the set temperature must be at least lower than the oxidation reaction temperature to avoid oxidation reaction during the unloading process, resulting in sample distortion. Typically but not limitedly, the cooling unit can adopt jacket heat exchange, and a soft connection is adopted between the heat exchange jacket and the external pipeline. The temperature measuring unit can adopt a thermocouple, and the arrangement quantity and position are selected according to needs to obtain the particle sample temperatures at different positions in the silo as much as possible.

[0036] The vacuum generator 3 includes a vacuum pump 31, an electric control cabinet 32, and an exhaust port 33. Among them, the electric control cabinet 32 can control the operating state of the vacuum pump 31; in the shutdown state, the vacuum generator 3 is in a through state, so its exhaust port 33 can be used as the system exhaust port at the same time, without the need to set an additional exhaust port. A vacuum generator pipeline control valve V2 is provided on the pipeline between the vacuum generator 3 and the silo 2 to control the on-off of the gas therebetween.

[0037] The inert gas supply device 4 is a nitrogen cylinder, and a pressure reducing valve V4 and a barometer 41 are provided at its outlet to accurately regulate the output gas pressure; a gas storage tank pipeline control valve V3 is provided on the pipeline between the inert gas supply device 4 and the sampler 1 to control the on-off of nitrogen. It should be noted that the functions of the gas storage tank pipeline control valve V3 and the pressure reducing valve V4 are somewhat repetitive. In theory, only a single valve can be used. However, considering the actual application, the pressure reducing valve V4 is only responsible for precise pressure regulation, while the gas storage tank pipeline control valve V3 is only responsible for pipeline on-off, which can be more convenient for operation and avoid the fine-tuning operation that needs to be performed on the pressure reducing valve V4 every time it is used, which is beneficial to improving the subsequent use efficiency.

[0038] The second embodiment

[0039] This embodiment provides a high-temperature thermochemical particle sampling method for the above-mentioned sampling system 100. For the convenience of understanding, it can be simplified to Figure 1 and simplified to Figure 2 At the same time, referring to Figure 3 , then the high-temperature thermochemical particle sampling method includes the following steps: inerting the silo atmosphere S1, inerting the sample atmosphere S2, vacuum sampling S3, sample cooling S4, and discharging S5.

[0040] The following is an explanation of each step.

[0041] Inerting the silo atmosphere S1:

[0042] Open the gas storage tank pipeline control valve V3 between the inert gas supply device 4 and the silo 2, and the vacuum generator pipeline control valve V2 between the silo 2 and the exhaust port 33 to form a through path. Open the inert gas supply device 4, regulate the output air pressure through the pressure reducing valve V4 and the barometer 41, fill the silo 2 with nitrogen, and drive the air atmosphere that originally filled the silo 2 to leave through the exhaust port 33.

[0043] Inerting the sample atmosphere S2:

[0044] Place the sampler 1 at the target sampling position. Keep the gas storage tank pipeline control valve V3 open, close the vacuum generator pipeline control valve V2, and open the sampler pipeline control valve V1 between the sampler 1 and the silo 2. Make nitrogen flow directly to the target sampling position.

[0045] Vacuum sampling S3:

[0046] Keep V1 and V3 open, and at the same time open V2 to keep nitrogen flushing inside the bin 2 and near the particle sample. Turn on the vacuum generator 3 so that nitrogen and the particle sample are sucked into the bin 2 together. The nitrogen will further leave through the exhaust port 33 of the vacuum generator, while the particle sample will be left at the bottom of the bin 2; monitor the weight gain value through the cantilever beam force sensor 23 until the sample amount reaches the target value, and then turn off the vacuum generator 3.

[0047] Sample cooling S4:

[0048] Remove the sampler 1, turn off V1, keep V2 and V3 open, let nitrogen enter the bin 2 and continuously leave through the exhaust port 33 to flush the particle sample in the bin 2, forcing the particles to quickly cool down below the oxidation temperature in nitrogen to avoid oxidation reaction (if the bin is equipped with a cooling unit, turn on the cooling unit while using nitrogen purge to increase the cooling speed);

[0049] Unloading S5:

[0050] Turn off the inert gas supply device 4, and at the same time turn off V1, V2 and V3. Open the discharge valve V21 to make the particle sample fall from the bin 2 to the discharge bin 22 under the action of gravity, completing the sample collection.

[0051] After sampling, analysis and testing methods such as thermogravimetric analysis can be adopted for the sampled particle sample to evaluate its reactivity, reaction process, etc.

[0052] If sampling at other positions is required subsequently, adjust the position of the sampler 1 accordingly and repeat S1 - S5.

[0053] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-temperature thermochemical particle sampling system, characterized in that, Comprising: A sampler for obtaining a thermochemical particle sample at a position to be sampled; A silo connected to the sampler through a pipeline, for temporarily storing the thermochemical particle sample and cooling the thermochemical particle sample therein to below the oxidation temperature; A vacuum generator connected to the silo through a pipeline, for providing negative pressure; An inert gas atmosphere supply device connected to the sampler and the silo through pipelines, for providing an inert gas atmosphere; A plurality of valves respectively arranged on the pipelines between the sampler and the silo, between the silo and the vacuum generator, and between the silo and the inert gas atmosphere supply device, for controlling the opening and closing of the pipelines where they are located.

2. The high-temperature thermochemical particle sampling system according to claim 1, wherein Further comprising: A sampling extension pipe connected to the sampler to increase the sampling distance; the sampler is of a tapered structure.

3. The high-temperature thermochemical particle sampling system according to claim 1 or 2, characterized in that The surfaces of the sampler and the sampling extension pipe are coated with a high reflectivity coating for reducing the absorption of incident light.

4. The high-temperature thermochemical particle sampling system according to claim 1 or 2, characterized in that, The high-temperature thermochemical particle sampling system is provided with an openable and closable system exhaust port on the pipeline between the silo and the vacuum generator, or the vacuum generator is selected as a vacuum pump that is a passage by itself in the shutdown state.

5. The high-temperature thermochemical particle sampling system according to claim 1, characterized in that The silo is equipped with a cooling and temperature measuring unit all around, the cooling unit is used for quickly cooling the particle sample in the silo, and the temperature measuring unit is used for monitoring the temperature of the particle sample in the silo; An electric valve is further arranged at the bottom of the silo for switching between the sealed state and the discharging state.

6. The high-temperature thermochemical particle sampling system according to claim 1, characterized in that The vacuum generator is configured with a corresponding electric control system capable of adjusting its running time and running intensity; A filter screen is further arranged between the vacuum generator and the silo to prevent the particle sample from being sucked into the vacuum generator.

7. The high-temperature thermochemical particle sampling system according to claim 1, wherein The inert gas atmosphere supply device has an outlet pressure regulating unit for controlling the outlet pressure and flow rate of the inert gas.

8. The high-temperature thermochemical particle sampling system according to claim 1, characterized in that, The inert gas atmosphere supply device can also switch different inert gas atmospheres.

9. The high-temperature thermochemical particle sampling system according to claim 1, wherein The silo is further provided with a cantilever beam type force sensor for real-time monitoring of the total weight of the silo and the particle sample therein, and a flexible connection is adopted between the silo and the pipelines in the system.

10. A high-temperature thermochemical particle sampling method for use in the high-temperature thermochemical particle sampling system according to any one of claims 1 to 9, characterized in that, Including the following steps: Silo atmosphere inerting stage: Turn on the inert gas atmosphere supply device, and turn on the valves between the inert gas atmosphere supply device and the silo, and between the silo and the exhaust port, so that the inert gas atmosphere fills the silo and drives the originally air atmosphere filled in the silo to leave through the exhaust port; Sample atmosphere inerting stage: Close the valve between the silo and the exhaust port, and turn on the valve between the sampler and the silo, so that the inert gas atmosphere directly reaches the sampling area and dilutes the area near the sample to a near-inert gas atmosphere; Vacuum sampling stage: Turn on the valve between the silo and the vacuum generator, and turn on the vacuum generator, so that the inert gas atmosphere from the inert gas atmosphere supply device, the particle sample and a small amount of near-inert gas atmosphere around the particle sample are sucked into the silo together, wherein the gas will further leave through the outlet of the vacuum generator, while the particle sample will be left at the bottom of the silo; Sample cooling stage: Turn off the vacuum generator, close the valve between the silo and the sampler, and turn on the valve between the silo and the exhaust port, so that the inert gas atmosphere enters the silo and continuously leaves through the exhaust port to wash the particle sample in the silo, forcing the particles to quickly cool to below the oxidation temperature in the inert gas atmosphere to avoid their oxidation reaction; Discharging stage: Shut down the inert gas supply device, and at the same time close all valves, open the silo, and take out the sample.

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