Efficient transportation, heat exchange and heat supply system

Abstract

The invention discloses a high-efficiency transportation, heat exchange and heat supply system, which realizes high-efficiency heat energy storage and transportation by using high-heat-capacity particles through the combination of a pneumatic transportation technology and a solid particle heat storage technology. The system comprises a solid particle storage bin, an air source system, a pneumatic conveying pipeline, a heat exchange device and an external heating and recycling unit, a fluidized bed heat exchanger is coupled with pneumatic conveying, additional fluidizing air is not needed, the energy storage density can reach 700-900 MJ / m < 3 > and is close to or exceeds that of a solution heat storage system, and the system has the advantages of low cost and high stability and flexibility. The device is suitable for industrial waste heat recovery, solar heat storage power generation and other scenes, and the heat energy utilization efficiency is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage and heat supply technology, and specifically relates to a high-efficiency transport, heat exchange and heating system. More specifically, it relates to a heating system that couples high-efficiency transport with fluidized bed heat exchange technology to achieve high-efficiency heat energy transfer of solid particles. Background Art

[0002] With the transformation of the global energy structure, the widespread use of renewable energy has placed higher demands on efficient energy storage and heating technologies. Traditional energy storage and heating systems mainly include liquid heat storage (such as molten salt and thermal oil), solid heat storage (such as metal oxides and ceramics), and phase change heat storage (such as hydrated salts and alloys). However, liquid heat storage systems generally require complex piping and pumping equipment, and are subject to problems such as high corrosion, high risk of leakage, and high maintenance costs. Although phase change heat storage has a higher energy storage density, it is expensive and has limited material selection.

[0003] Solid thermal energy storage materials have attracted widespread attention in recent years due to their excellent thermal stability, high heat storage density, and wide availability. However, traditional solid particle thermal energy storage systems, which generally rely on gravity or mechanical transport, suffer from inflexible transport paths, bulky and complex equipment, and high operating costs, making it difficult to achieve stable, continuous, and efficient thermal energy output.

[0004] Pneumatic conveying, as an efficient method for transporting solid particles, is widely used in industries such as chemicals and building materials. However, its application in energy storage and heating has not been fully explored, resulting in its inability to compete with liquid conveying systems in terms of energy density and system efficiency. Therefore, there is an urgent need for an efficient system that combines pneumatic conveying with energy storage and heating to achieve high energy density and low-cost thermal energy storage and transportation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a highly efficient transport, heat exchange, and heat supply system. By combining pneumatic conveying technology with solid particle heat storage technology and coupling it with a fluidized bed heat exchanger, this system significantly improves energy storage density, approaching or even reaching the energy density of liquid conveying systems while reducing system complexity and maintenance costs. This system leverages the high heat capacity and dynamic heat transfer characteristics of solid particles during pneumatic conveying to achieve efficient thermal energy storage, transport, and release, overcoming the problems of low transport efficiency, inflexible layout, and insufficient heating capacity found in existing solid heat storage systems.

[0006] The present invention provides a high-efficiency heat transport, heat exchange and heat supply system, comprising:

[0007] Solid particle storage bin, used to store high-temperature solid particles;

[0008] The air source system is connected to the solid particle storage bin and is used to provide compressed air or inert gas to drive the particles to circulate in the system;

[0009] The pneumatic conveying pipeline connects the solid particle storage bin, heat exchange device and cooling system to form a closed-circuit circulation channel for particles to achieve particle transportation;

[0010] The heat exchange device is connected to the solid particle storage bin through a pneumatic conveying pipeline. It uses a fluidized bed heat exchanger to transfer the heat of the high-temperature solid particles to the working medium.

[0011] The external heating and recovery unit heats the low-temperature particles after releasing heat energy through an external heating device and recovers them to the solid particle storage bin.

[0012] According to a preferred embodiment of the present invention, the solid particle storage bin is lined with high-temperature-resistant stainless steel or ceramic, and its outer wall is covered with a high-efficiency thermal insulation layer (such as ceramic fiber or vacuum insulation board). The heat storage medium is selected from solid particles with high heat capacity and strong thermal stability (such as metal oxide particles, ceramic particles, or silica sand particles), with a particle size of 0.3-2mm and an operating temperature range of 300°C-1000°C. The particles are heated to the target temperature by an external heating device (such as an electric heater, solar collector, or industrial waste heat exchanger) and fed into the bin through a feed port at the top of the bin. A temperature sensor is installed inside the bin to monitor the particle status in real time.

[0013] According to a preferred embodiment of the present invention, the gas source system includes a compressor and a gas storage tank. Compressed air or inert gas is commonly used, with a gas pressure range of 0.1-0.8 MPa. Equipped with a pressure regulating valve and flow meter, the airflow rate and pressure can be flexibly adjusted according to conveying requirements, ensuring stable and efficient particle delivery.

[0014] According to a preferred embodiment of the present invention, the pneumatic conveying pipeline is constructed of high-temperature and wear-resistant materials (such as stainless steel or ceramic coatings), has an inner diameter of 50-200 mm, and is wrapped with an insulation layer to reduce heat loss. The pipeline design takes turbulence effects into account, optimizing the particle-gas mixing ratio (solid-to-gas mass flow ratio) to increase the delivery concentration.

[0015] According to a preferred embodiment of the present invention, the heat exchange device transfers heat from high-temperature solid particles to a working medium for heating, power generation, or other industrial applications. The heat exchanger eliminates the need for additional fluidizing air and directly utilizes pneumatically conveyed airflow to drive the particle flow, simplifying the structure and improving heat exchange efficiency. Pneumatically conveyed particles come into direct or indirect contact with the working medium (such as water, air, or thermal oil) within the heat exchanger. The heat exchanger is made of high-temperature resistant alloys or ceramics, and the output temperature can be adjusted according to demand.

[0016] According to a preferred embodiment of the present invention, the external heating and recovery unit heats the low-temperature pellets after releasing heat energy using an external heat source and recovers them to the storage bin, forming a closed loop. The external heating and recovery unit includes an external heating device and a pellet recovery pipeline. The pellets are heated to the target temperature by the external heating device (such as an electric heater, solar collector, or industrial waste heat exchanger), and the recovery pipeline returns the pellets to the storage bin via low-pressure pneumatic conveying.

[0017] The present invention further provides a solid particle heat storage and heating method based on pneumatic conveying using the above system, comprising the following steps:

[0018] Particle heating and storage: An external heating device heats the solid particles to a target temperature of 300°C-1000°C and stores them in a solid particle storage bin, which stores high-temperature solid particles and maintains the temperature of the solid particles at 300°C-1000°C.

[0019] When solid particles need to be transported, pneumatic conveying starts: the air source system provides compressed air or inert gas (pressure 0.1-0.8MPa) to drive the high-temperature particles from the storage bin to the heat exchange device through the pneumatic conveying pipeline.

[0020] Heat transfer: In the heat exchange device, the pneumatically conveyed particles fully exchange heat with the working medium (such as water, air or thermal oil), releasing heat energy for heating or power generation.

[0021] Particle reheating: After releasing heat energy, the particles enter the external heating and recovery unit and are heated to the target temperature by the external heating device.

[0022] Particle recovery: The reheated particles are returned to the solid particle storage bin through the recovery pipeline, completing the closed-loop cycle and preparing for the next delivery.

[0023] The present invention has at least the following advantages:

[0024] (1) The coupling technology of pneumatic conveying and fluidized bed heat exchange replaces the fluidizing air (fluidizing medium) required for traditional fluidized bed heat exchange, allowing particles to flow at high speed in a closed loop, improving system response speed and layout flexibility;

[0025] (2) By regulating the solid-gas mass flow rate ratio, pipeline pressure and conveying speed, a high conveying concentration of solid particles per unit volume can be achieved, thereby achieving a unit volume energy density close to or even exceeding that of the liquid heat storage system (up to 700-900MJ / m 3 );

[0026] (3) Solid particles are low-cost, high-temperature resistant, non-toxic and non-corrosive. The system does not require complex liquid pumping equipment, which reduces maintenance costs. It is suitable for scenarios such as solar thermal power generation, industrial waste heat recovery, high-temperature thermochemical cycles and distributed heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention discloses a solid particle storage, transportation and heat supply system using pneumatic conveying technology.

[0028] Reference numerals: 1-solid particle storage bin; 2-air source system; 3-pneumatic conveying pipeline; 4-heat exchange device; 5-external heating and recovery unit. DETAILED DESCRIPTION

[0029] The present invention will be further described and illustrated below in conjunction with specific embodiments. The embodiments are merely illustrative of the present disclosure and do not limit its scope. The technical features of the various embodiments of the present invention may be combined accordingly, provided that there is no conflict between them.

[0030] Example 1:

[0031] This example describes a pneumatically conveyed solid particle heat storage and supply system combined with solar thermal collection for nighttime power generation. This system, centered on pneumatic conveying technology, achieves high-density thermal energy storage and transport, creating a high-temperature thermochemical heat storage system suitable for daytime heat storage and nighttime heat supply. It is suitable for solar thermal power generation or distributed combined heat and power (CHP) scenarios in remote areas.

[0032] like Figure 1 As shown, the solid particle heat storage and heating system based on pneumatic conveying mainly includes: a solid particle storage bin 1, an air source system 2, a pneumatic conveying pipeline 3, a heat exchange device 4, and an external heating and recovery unit 5, wherein:

[0033] Solid particle storage bin 1 is made of high temperature resistant stainless steel with a capacity of 100m 3 The inner layer is lined with ceramic material, and the outer wall is covered with a vacuum insulation layer. Composite metal oxide heat storage particles with a particle size of 1mm are used, and the operating temperature is 800°C-900°C. It should be noted that the choice of composite metal oxide heat storage particles in this embodiment is merely exemplary. Alternatively, solid particles can be used as a heat storage medium with high heat capacity and strong thermal stability, such as ceramic particles or silica sand particles. In this embodiment, the solid particle storage bin 1 is equipped with a temperature sensor to monitor the particle status in real time.

[0034] Air source system 2 includes an air compressor and an air storage tank. The air compressor power is 80kW and the air storage tank capacity is 3m 3 , used to provide air at a pressure of 0.3-0.6MPa. Air source system 2 is equipped with a flow meter and a pressure regulating valve to control the delivery rate of 0.5-2t / h and the solid-gas mass flow ratio of 15:1.

[0035] The pneumatic conveying pipe 3 has a diameter of 150mm and is made of stainless steel. The inner wall is provided with a ceramic coating and the outer wall is provided with a vacuum insulation layer. The conveying concentration is up to 45kg / m 3 .

[0036] The heat exchange device 4 uses a fluidized bed heat exchanger, which is made of high-temperature resistant ceramic material. The pneumatic conveying system structure consisting of the air source system and the pneumatic conveying pipeline is integrated with the heat exchange device to form a "transportation-heat exchange coupling zone". The high-temperature particles flow through the heat exchanger under continuous conveying and directly exchange heat with the boiler feed water. The heat exchange efficiency can reach 85%-90%, and no additional fluidizing air is required. The boiler feed water pipeline in the fluidized bed heat exchanger can be arranged vertically to reduce friction and collision with the high-temperature particles.

[0037] In order to optimize the heat exchange effect of the fluidized bed heat exchanger, a guide plate or an air flow distributor may be provided at the bottom of the fluidized bed heat exchanger to improve the uniformity of air flow distribution in the fluidized bed.

[0038] Furthermore, different operating modes can be adopted in the fluidized bed heat exchanger according to the required working conditions; for example, in one optional operating mode, the gas source system 2 transports the particle-containing airflow at a constant delivery rate and solid-gas mass flow ratio, and the particle-containing airflow exchanges heat with the boiler feed water in the fluidized bed heat exchanger before leaving the fluidized bed heat exchanger. In another optional mode, at the beginning, the airflow velocity of the gas source system 2 is low (but still able to fluidize the solid particles), the solid particles begin to fluidize in the fluidized bed, but the solid particles will not be carried out of the fluidized bed heat exchanger with the airflow, and the solid particles exchange heat with the boiler feed water. After the particles in the fluidized bed heat exchanger reach a certain mass or the average temperature of the solid particles drops to a set value, the delivery rate is increased so that the solid particles can be carried out of the fluidized bed heat exchanger by the airflow; after the temperature of the solid particles in the fluidized bed heat exchanger returns to the preset value, the operation is repeated. Therefore, the fluidized bed heat exchanger of the present invention can flexibly adjust the operating mode according to needs.

[0039] The external heating and recovery unit 5 includes a solar collector and a recovery pipe. The pipe has a diameter of 100 mm and uses 0.1 MPa low-pressure pneumatic conveying. The solar collector heats the particles to the target temperature (in this embodiment, the operating temperature of the solid particles is 800°C-900°C). The reheated particles are then returned to the solid particle storage bin through the recovery pipe, completing the closed-loop cycle and preparing for the next delivery.

[0040] In this embodiment, the tower solar collector heats the solid particles to 850°C and stores them in the solid particle storage bin 1. The air source system 2 provides 0.4MPa air, which drives the high-temperature particles to be transported to the heat exchange device 4 at a speed of 15m / s through the pneumatic conveying pipe 3, and the particle temperature is maintained above 830°C. The pneumatically conveyed particles exchange heat with the boiler feed water in the heat exchange device 4 to generate medium-pressure steam. After releasing the heat energy, the particles enter the external heating and recovery unit 5, and the heat storage particles are heated to the target temperature through the solar collector. The reheated particles return to the solid particle storage bin 1 through the recovery pipe to complete the closed-loop cycle. The conveying rate and solid-gas mass flow ratio can be adjusted according to demand to optimize the heat exchange efficiency.

[0041] This implementation method uses pneumatic conveying to achieve long-distance transportation of high-temperature particles, combined with a fluidized bed heat exchanger and a vacuum insulated storage bin, significantly improving energy storage density and system efficiency. Under test conditions, the system unit heat storage volume is 820MJ / m 3 , the heat exchange efficiency reaches 83%, which is suitable for solar thermal storage power generation scenarios.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An efficient transport, heat exchange and heating system, characterized in that: include: Solid particle storage bin, used to store high-temperature solid particles; The air source system is connected to the solid particle storage bin and is used to provide compressed air or inert gas to drive the particles to circulate in the system; The pneumatic conveying pipeline connects the solid particle storage bin, heat exchange device and cooling system to form a closed-circuit circulation channel for particles to achieve particle transportation; The heat exchange device is connected to the solid particle storage bin through a pneumatic conveying pipeline. It uses a fluidized bed heat exchanger to transfer the heat of the high-temperature solid particles to the working medium. The external heating and recovery unit heats the low-temperature particles after releasing heat energy through an external heating device and recovers them to the solid particle storage bin.

2. The system according to claim 1, wherein: The solid particles are solid heat storage particles such as metal oxide particles, silica sand or ceramic particles, with a particle size of 0.3-2 mm, a heat capacity of 0.8-1.2 kJ / (kg·K), and an operating temperature range of 300°C-1000°C.

3. The system according to claim 1, wherein: The pressure range of the compressed air or inert gas used in the air source system is 0.2-0.8 MPa. The air source system or the pneumatic conveying pipeline is equipped with a flow meter and a pressure regulating valve to control the solid-gas mass flow ratio of the particle-containing airflow in the pneumatic conveying pipeline to be 5:1 to 20:1, and the conveying speed is 5-20 m / s.

4. The system according to claim 1, wherein: The pneumatic conveying pipeline is made of stainless steel or ceramic coating material, and the outer layer is covered with vacuum insulation material.

5. The system according to claim 1, wherein: The particle concentration in the particle-laden airflow discharged from the solid particle storage bin is 30-50 kg / m 3 , energy storage density is 700-900MJ / m 3 .

6. The system according to claim 1, wherein: The solid particle storage bin is made of high-temperature resistant stainless steel or ceramic lining material, and the outer wall is covered with ceramic fiber or vacuum insulation layer, and the heat loss rate is less than 0.3% / day.

7. The system according to claim 1, wherein: The fluidized bed heat exchanger forms a coupled structure with the pneumatic conveying system. The solid particles complete heat exchange with the working medium during the conveying process, and the fluidized bed heat exchanger does not require additional fluidizing air. The heat exchange efficiency is 85%-90%, the working medium is water, air or thermal oil, and the output temperature of the working medium is 70°C-500°C.

8. The system according to claim 1, wherein: The system achieves dynamic control of particle transportation by adjusting air flow rate, pipeline pressure and solid-gas ratio to adapt to different thermal energy requirements.

9. The system according to claim 1, wherein: The external heating and recovery unit includes an external heating device and a particle recovery pipeline. The solid particles are heated to the target temperature by the external heating device, and the recovery pipeline returns the particles to the storage bin through low-pressure pneumatic conveying; the external heating device is an electric heater, a solar collector or an industrial waste heat exchanger.

10. A solid particle heat storage and heating method based on the system according to any one of claims 1 to 9, characterized in that The steps include: The temperature of solid particles in the solid particle storage bin is maintained at 300℃-1000℃; When solid particles need to be transported, the air source system provides compressed air or inert gas to drive the high-temperature solid particles in the solid particle storage bin to flow to the heat exchange device through the pneumatic conveying pipeline; In the heat exchange device, the high-temperature solid particles transported by pneumatic means fully exchange heat with the working medium, releasing heat energy. The working medium absorbs the heat flow and uses it for heating or power generation. The solid particles after releasing heat energy enter the external heating and recovery unit and are heated to the storage temperature in the solid particle storage bin by the external heating device; The reheated solid particles are returned to the solid particle storage bin through the recovery pipe, completing the closed-loop cycle and preparing for the next transportation.

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