CN106052451A - Graphite sensible heat exchange device and heat exchange method thereof - Google Patents

Abstract

A graphite sensible heat storage and heat exchange device, including graphite heat storage stack, antioxidant, refractory bricks, heat exchange circulation air duct, insulation layer, supporting steel frame, inlet connecting pipe, air supply port, one-way valve, nitrogen tank, Frequency conversion fan, heat exchanger, first temperature sensor, outlet connecting pipe, second temperature sensor, pressure sensor, control cabinet, heating rod, third temperature sensor, graphite stack consists of several heating graphite blocks, heat storage graphite blocks, heat exchange Graphite blocks are staggered and stacked. The present invention improves the convenience of the heating system by utilizing the high thermal diffusivity of graphite; while increasing the heat storage density and ensuring the heat exchange effect, it avoids and reduces the loss of graphite due to abrasion and oxidation, and improves the graphite’s thermal conductivity. Longer service life and reduced maintenance costs.

Description

A graphite sensible heat exchange device and heat exchange method thereof

technical field

The invention relates to a graphite heat storage heat exchange device and a heat exchange method thereof, belonging to the technical field of heat storage utilization.

Background technique

Energy storage technology is one of the key core devices to realize the smart energy grid system. Heat storage technology is an important part of the field of energy storage technology. Thermal storage technology has broad application prospects in solar thermal power generation, utilization of industrial flue gas waste heat, and peak-valley electricity regulation heating. Among them, in terms of peak and valley electricity regulation and heating, the cheap electric energy during the low-peak electricity consumption is converted into heat energy for storage through heat storage technology, and the heat storage system is used for direct heat supply when there is a demand for heat load, which not only achieves the regulation of electricity consumption The purpose of balance also improves the economy of the heating system, which has good economy.

Heat storage technology mainly includes sensible heat storage and latent heat phase change heat storage. In terms of sensible heat storage, Chinese patent CN201510169131.7 invented an electric heating solid heat storage device, but the invention uses low thermal conductivity coefficient of heat storage bricks, so it is necessary to control the size of heat storage bricks, and arrange a large number of heating wires to ensure the uniform temperature of the system and the adequacy of heat exchange during heating, which makes the heating process more complicated; in addition, in order to ensure the system The uniformity of heat exchange requires uniform arrangement of air ducts and the uniformity of heat exchange surface arrangement as much as possible, all of which bring complexity to the system design.

Therefore, for the sensible heat system, how to ensure the temperature uniformity of the heat storage system during the heating and heat release process, and at the same time avoid the system being too complicated, and establish a heat storage system with a simple structure and easy installation has become the development of the sensible heat storage system. the problem we are facing.

In addition, for the heat storage system, the higher the heat storage density per unit mass, the smaller the heat storage material required, and the better the economy of the system. Therefore, for the sensible heat storage system, how to further increase the heat storage temperature of the heat storage system and increase the heat storage density is also an important direction for the development of the sensible heat storage system.

Contents of the invention

The object of the present invention is to overcome the above disadvantages, and propose a graphite sensible heat storage heat exchange device and heat exchange method.

To achieve the above object, the present invention adopts the following technical solutions:

A graphite sensible heat storage and heat exchange device, comprising a graphite heat storage stack, an antioxidant, refractory bricks, a heat exchange circulation air duct, an insulation layer, an inlet connecting pipe, an air supply port, a one-way valve, a nitrogen tank, a frequency conversion fan, and a Heater, first temperature sensor, outlet connecting pipe, second temperature sensor, pressure sensor, control cabinet, heating rod, third temperature sensor; the periphery of the graphite heat storage pile is built with refractory bricks, and the graphite heat storage pile and refractory bricks The space is sealed by filling anti-oxidants, and the insulation layer is installed on the periphery of the refractory bricks. There are gaps between the two short sides and the top surface of the refractory bricks and the insulation layer to form a heat exchange circulation air duct. The insulation layer on the long side and the insulation layer The refractory bricks are closely fitted, and the bottom of the graphite heat storage pile is equipped with a supporting steel frame; the inlet connecting pipes are respectively connected with the inlet of the heat exchange circulation air duct and the outlet of the heat source of the heat exchanger. There is an air supply port, which is connected to the nitrogen tank, and a one-way valve is installed between the air supply port and the nitrogen tank; a pressure sensor is installed in the heat exchange circulation air duct; a first temperature sensor is installed at the outlet of the cold source of the heat exchanger; the outlet is connected to a pipeline They are respectively connected to the outlet of the heat exchange circulation air duct and the heat source inlet of the heat exchanger, the outlet connecting pipe is equipped with a second temperature sensor, and the graphite heat storage pile is respectively equipped with a heating rod and a number of third temperature sensors; the first temperature sensor, the second The temperature sensor, the pressure sensor, the heating rod and the third temperature sensor are respectively connected with the control cabinet.

The graphite heat storage stack is composed of a number of heated graphite blocks, heat storage graphite blocks, and heat exchange graphite blocks stacked in a staggered manner. The four sides of the graphite heat storage stack and the outer layer of the bottom surface are composed of heated graphite blocks or heated graphite blocks It is composed of heat-storage graphite blocks arranged crosswise, the top layer is composed of heat-exchange graphite blocks; the interior is composed of heat-storage graphite blocks.

There are heating rod installation holes on the heating graphite block, and the heating rod installation holes are installed in transition with the heat exchanger, and the heating rod installation holes on the heating graphite block are arranged outward.

The heat exchange graphite block is composed of heat exchange channels and connecting blocks, and the height ratio between them is between 1.0 and 3.0.

The height difference between the graphite heat storage stack and the refractory brick is the height of the heat exchange channel of the graphite block; the gap between the top of the graphite heat storage stack and the insulation layer is 1-2 times the diameter of the heat exchange channel of the graphite block.

The heat exchange working medium in the heat exchange circulation air duct is nitrogen, and the heat exchange circulation air duct maintains a positive pressure.

The heat exchangers include gas-gas type and gas-liquid type, and specific forms include shell-and-tube heat exchangers and plate heat exchangers.

The antioxidant includes any one of silicon carbide, molybdenum disilicide and refractory brick powder.

A heat exchange method using the graphite sensible heat storage heat exchange device. During the heat storage process, the control cabinet controls the heating rod to heat the graphite according to the feedback from the third temperature sensor when the temperature of the graphite is lower than the set threshold value. The heated graphite block in the heat storage pile, the graphite heat storage pile uses the high thermal diffusivity characteristics of graphite to quickly transfer the heat of the heated graphite block to the heat storage graphite block and the heat exchange graphite block, so that the temperature distribution of the entire graphite heat storage pile is even ; The arrangement of antioxidants and refractory bricks makes the main part of the graphite heat storage pile not in contact with the heat exchange gas, avoiding the high temperature oxidation of graphite. During the heat exchange process, the frequency conversion fan adjusts the circulating air volume according to the temperature sensed by the second temperature sensor and the first temperature sensor and the heat exchange power requirements. , flows into the heat exchanger through the outlet connecting pipe, and realizes heat exchange through the heat exchanger. The one-way valve is opened and closed according to the measured value of the pressure sensor. When the pressure of the heat exchange circulation air duct is lower than the threshold value, the one-way valve is opened, and the nitrogen tank supplies nitrogen to the heat exchange circulation air duct to ensure positive pressure and avoid air leakage. .

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

(1) The present invention utilizes the high thermal diffusivity of graphite, adopts the method of local heat exchange and other contact surfaces are treated with sealing and oxygen barrier, while ensuring the heat storage density and heat exchange effect, it avoids the uniform arrangement of heat exchange air ducts It leads to the loss of graphite due to wear and oxidation, which improves the service life of graphite and reduces maintenance costs.

(2) The local arrangement of the heat exchange graphite block of the present invention makes it more convenient to replace the lost graphite and reduces the maintenance cost.

(3) The present invention utilizes the high thermal diffusivity of graphite, reduces the number of heating elements, realizes the free combination of heating graphite block and heat storage graphite block, makes the heating system simple and easy, and reduces the investment cost of the system.

Description of drawings

Fig. 1 is a schematic diagram of graphite sensible heat storage heat exchange device;

Fig. 2 is a schematic diagram of the layout of a graphite heat storage pile;

Fig. 3 is the structural diagram of heating graphite block;

Fig. 4 is a schematic structural diagram of a heat exchange graphite block.

In the figure: Graphite heat storage pile 1, antioxidant 2, refractory brick 3, heat exchange circulation air duct 4, insulation layer 5, supporting steel frame 6, inlet connecting pipe 7, air supply port 8, one-way valve 9, nitrogen tank 10 , frequency conversion fan 11, heat exchanger 12, first temperature sensor 13, outlet connection pipe 14, second temperature sensor 15, pressure sensor 16, control cabinet 17, heating rod 18, third temperature sensor 19, heating graphite block 20, Heat storage graphite block 21, heat exchange graphite block 22, heating rod installation hole 23, heat exchange channel 24, connecting block 25.

detailed description

As shown in Figure 1-4, a graphite sensible heat storage heat exchange device includes graphite heat storage stack 1, antioxidant 2, refractory brick 3, heat exchange circulation air duct 4, insulation layer 5, inlet connecting pipe 7, Air supply port 8, one-way valve 9, nitrogen tank 10, frequency conversion fan 11, heat exchanger 12, first temperature sensor 13, outlet connecting pipe 14, second temperature sensor 15, pressure sensor 16, control cabinet 17, heating rod 18 , the third temperature sensor 19; the periphery of the graphite heat storage pile 1 is built with refractory bricks 3, between the graphite heat storage pile 1 and the refractory bricks 3 is sealed by filling the antioxidant 2, and the periphery of the refractory bricks is equipped with an insulation layer 5, There are gaps between the refractory bricks 3 on the two short sides and the top surface and the insulation layer to form a heat exchange circulation air duct 4, the insulation layer 5 on the long side is closely attached to the refractory bricks 3, and the bottom of the graphite heat storage pile 1 is arranged There is a supporting steel frame 6; the inlet connecting pipe 7 is connected with the inlet of the heat exchange circulation air duct 4 and the heat source outlet of the heat exchanger 12 respectively; The gas port 8 is connected to the nitrogen tank 10, and a check valve 9 is installed between the gas supply port 8 and the nitrogen tank 10; a pressure sensor 16 is installed in the heat exchange circulation air duct 4; a first temperature sensor 13 is installed at the cold source outlet of the heat exchanger; The outlet connection pipe 14 is respectively connected with the outlet of the heat exchange circulation air duct 4 and the heat source inlet of the heat exchanger 12, the outlet connection pipe 14 is equipped with a second temperature sensor 15, and the graphite heat storage pile 1 is respectively equipped with a heating rod 18 and a number of third temperature sensors. The temperature sensor 19 ; the first temperature sensor 13 , the second temperature sensor 15 , the pressure sensor 16 , the heating rod 18 and the third temperature sensor 19 are connected to the control cabinet 17 respectively.

Graphite heat storage stack 1 is formed by stacking and stacking a number of heated graphite blocks 20, heat storage graphite blocks 21, and heat exchange graphite blocks 22 in a staggered arrangement. 20 arrangement or composed of heating graphite blocks 20 and heat storage graphite blocks 21 intersecting arrangement, the top layer is composed of heat exchange graphite blocks 22; the interior is composed of heat storage graphite blocks 21.

There is a heating rod installation hole 23 on the heating graphite block 20, and the heating rod installation hole 23 is installed in a transitional fit with the heat exchanger 12, and the heating rod installation hole 23 on the heating graphite block 20 is arranged outward.

The heat exchange graphite block 22 is composed of two parts, the heat exchange channel 24 and the connection block 25, and the height ratio of the heat exchange channel 24 and the connection block 25 is between 1.0 and 3.0.

The height difference between the graphite heat storage pile 1 and the refractory brick 3 (the graphite heat storage pile 1 is higher than the height of the refractory brick 3) is the height of the heat exchange channel 24 of the graphite block 22; the graphite heat storage pile 1 top and the insulation layer The gap between 5 is 1-2 times of the diameter of the heat exchange channel 24 of the graphite block 22 .

The heat exchange working medium in the heat exchange circulation air duct 4 is nitrogen, and the heat exchange circulation air duct 4 maintains a positive pressure.

The heat exchanger 12 includes a gas-gas type and a gas-liquid type, and specific forms include a shell-and-tube heat exchanger and a plate heat exchanger.

The antioxidant 2 includes any one of silicon carbide, molybdenum disilicide and refractory brick powder.

A heat exchange method using the graphite sensible heat storage heat exchange device, specifically as follows: during the heating and heat storage process, the control cabinet 17, according to the feedback from the third temperature sensor 19, when the graphite temperature is lower than the set threshold value, Control the heating rod 18 to heat the heated graphite block 20 in the graphite heat storage stack 1. The graphite heat storage stack 1 uses the high thermal diffusivity characteristics of graphite to quickly transfer the heat of the heated graphite block 20 to the heat storage graphite block 21 and the heat exchange graphite block 22, so that the temperature distribution of the entire graphite heat storage pile 1 is uniform; the arrangement of the antioxidant 2 and the refractory brick 3 makes the main part of the graphite heat storage pile 1 not in contact with the heat exchange gas, avoiding the high temperature oxidation of graphite. During the heat exchange process, the frequency conversion fan 11 adjusts the circulation air volume according to the temperature sensed by the second temperature sensor 15 and the first temperature sensor 13 and the heat exchange power requirement, and the low-temperature nitrogen gas passes through the inlet connecting pipe 7 and the heat exchange circulation air duct 4 in the heat exchange process. After heat exchange in the tunnel 24 , it flows into the heat exchanger 12 through the outlet connecting pipe 14 , and the heat exchange is realized through the heat exchanger 12 . The one-way valve 9 is opened and closed according to the measured value of the pressure sensor 16. When the pressure of the heat exchange circulation air duct 4 is lower than the threshold value, the one-way valve 9 is opened, and the nitrogen tank 10 supplies nitrogen to the heat exchange circulation air duct 4 to ensure Positive pressure to avoid air leakage.

Concrete work process of the present invention is as follows:

During the heating process, the control cabinet 17 controls the heating rod 18 to heat the heated graphite block 20 in the graphite heat storage pile 1 according to the feedback of the third temperature sensor 19 when the graphite temperature is lower than the set threshold value, and the graphite heat storage pile 1 utilizes The high thermal diffusivity of graphite can quickly transfer the heat of the heated graphite block 20 to the heat storage graphite block 21 and the heat exchange graphite block 22, so that the temperature distribution of the entire graphite heat storage stack 1 is uniform. When the graphite temperature is higher than the set threshold value , stop heating. During the heat exchange process, the frequency conversion fan 11 is turned on, and the low-temperature nitrogen gas flows into the heat exchanger 12 through the outlet connection pipe 14 after passing through the inlet connection pipe 7 and the heat exchange circulation air duct 4 to exchange heat in the heat exchange channel 24, and passes through the heat exchange The device 12 realizes heat exchange. During the heat exchange process, it is necessary to adjust the flow rate of the variable frequency fan according to the heat exchange power demand of the system and the temperature values of the second temperature sensor 15 and the first temperature sensor 13 until the temperature of the first temperature sensor 13 meets the requirements. During the whole process, the one-way valve 9 is opened and closed according to the measurement value of the pressure sensor 16. When the pressure of the heat exchange circulation air duct 4 is lower than the threshold value, the one-way valve 9 is opened, and the nitrogen tank 10 flows to the heat exchange circulation air duct 4. Nitrogen is added inside to ensure positive pressure and avoid air leakage.

In the specific implementation process, it is inevitable that part of the air will leak in, resulting in the loss of the heat exchange graphite block 22 of the graphite heat storage pile 1 under the action of oxidation and wear in the high temperature process, while the graphite heat storage pile 1 The main part will not be worn out, and only the heat-exchanging graphite block 22 needs to be replaced regularly during the specific operation process, which greatly reduces the loss and maintenance cost of the graphite heat storage stack 1 .

Therefore, the present invention makes full use of the characteristics of the high thermal diffusivity of graphite, and ensures effective heat exchange by setting a heat exchange surface on the top, while the main part is sealed for oxygen isolation, so as to ensure heat exchange and minimize the heat transfer of graphite. The loss of the system reduces the maintenance cost of the system and improves the economy of the system.

Claims (8)

1. a graphite sensible heat regenerative heat exchange device, it is characterised in that include graphite accumulation of heat heap (1), antioxidant (2), fire-resistant Brick (3), recuperated cycle air channel (4), heat-insulation layer (5), inlet connecting branch road (7), gas supplementing opening (8), check valve (9), nitrogen pot (10), frequency conversion fan (11), heat exchanger (12), the first temperature sensor (13), outlet connecting pipe road (14), the second temperature sensing Device (15), pressure transducer (16), switch board (17), heating rod (18), three-temperature sensor (19)；Graphite accumulation of heat heap (1) Outer brick work have refractory brick (3), between graphite accumulation of heat heap (1) and refractory brick (3) by landfill antioxidant (2) seal, The periphery of refractory brick is provided with heat-insulation layer (5), leaves sky between refractory brick (3) and the heat-insulation layer of the short side of two of which and end face Gap forms recuperated cycle air channel (4), and the heat-insulation layer (5) of long side surface fits tightly with refractory brick (3), the end of graphite accumulation of heat heap (1) Portion is provided with supporting steel frame (6)；Inlet connecting branch road (7) goes out with recuperated cycle air channel (4) entrance and heat exchanger (12) thermal source respectively Mouth is connected, and inlet connecting branch road (7) are provided with frequency conversion fan (11), and inlet connecting branch road (7) are provided with gas supplementing opening (8), QI invigorating Mouth (8) is connected with nitrogen pot (10), equipped with check valve (9) between gas supplementing opening (8) and nitrogen pot (10)；Recuperated cycle air channel (4) Built with pressure transducer (16)；The outlet of heat exchanger low-temperature receiver is provided with the first temperature sensor (13)；Outlet connecting pipe road (14) Being connected with recuperated cycle air channel (4) outlet and heat exchanger (12) thermal source inlet respectively, outlet connecting pipe road (14) are provided with second Temperature sensor (15), graphite accumulation of heat heap (1) is separately installed with heating rod (18) and some three-temperature sensors (19)；The One temperature sensor (13), the second temperature sensor (15), pressure transducer (16), heating rod (18), three-temperature sensor (19) it is connected with switch board (17) respectively；Graphite accumulation of heat heap (1) by some heating graphite blocks (20), accumulation of heat graphite block (21), change Hot graphite block (22) stagger arrangement superposition is piled up and is formed, four sides of graphite accumulation of heat heap (1) and one layer, the periphery of bottom surface by heating Graphite block (20) or by heating graphite block (20) and accumulation of heat graphite block (21) arranged crosswise form, end face one layer is by heat exchange graphite block (22) composition；Inside is made up of accumulation of heat graphite block (21).

A kind of graphite sensible heat regenerative heat exchange device the most according to claim 1, it is characterised in that described heating graphite block (20) there are heating rod installing hole (23), heating rod installing hole (23) to install with heat exchanger (12) interference fits on, heat graphite block (20) the heating rod installing hole (23) on is outwardly disposed.

A kind of graphite sensible heat regenerative heat exchange device the most according to claim 1, it is characterised in that described heat exchange graphite block (22) being made up of heat exchange duct (24) and contiguous block (25) two parts, the aspect ratio of heat exchange duct (24) and contiguous block (25) is Between 1.0～3.0.

A kind of graphite sensible heat regenerative heat exchange device the most according to claim 1, it is characterised in that described graphite accumulation of heat heap (1) with the height in the heat exchange duct (24) that difference in height is graphite block (22) of refractory brick (3)；Graphite accumulation of heat heap (1) top and guarantor 1-2 times of the aperture, heat exchange duct that gap is graphite block (22) between temperature layer (5).

A kind of graphite sensible heat regenerative heat exchange device the most according to claim 1, it is characterised in that described recuperated cycle wind Heat-exchange working medium in road (4) is nitrogen, keeps malleation in recuperated cycle air channel (4).

A kind of graphite sensible heat regenerative heat exchange device the most according to claim 1, it is characterised in that described heat exchanger (12) Including gas-gas type and gas-liquid type, concrete form includes shell-and-tube heat exchanger and plate type heat exchanger.

A kind of graphite sensible heat regenerative heat exchange device the most according to claim 1, it is characterised in that described antioxidant (2) Including in carborundum, molybdenum disilicide, refractory brick powder any one.

8. one kind utilizes the heat-exchange method of graphite sensible heat regenerative heat exchange device described in claim 1, it is characterised in that: heat storage During, switch board (17), according to the feedback of three-temperature sensor (19), when graphite temperature is less than when setting threshold values, controls to add Heating graphite block (20) in hot pin (18) heating graphite accumulation of heat heap (1), graphite accumulation of heat heap (1) utilizes the high thermal diffusion system of graphite Number feature, quickly passes to accumulation of heat graphite block (21) and heat exchange graphite block (22) by the heat of heating graphite block (20) so that whole The uniformity of temperature profile of individual graphite accumulation of heat heap (1)；Antioxidant (2) and the layout of refractory brick (3) so that graphite accumulation of heat heap (1) Main part do not contact with recuperated gas, it is to avoid the high-temperature oxydation of graphite；In heat transfer process, frequency conversion fan (11) is according to second Temperature sensor (15) and the temperature sensor of the first temperature sensor (13) and heat exchange power requirement, regulate air circulation, low Temperature nitrogen through inlet connecting branch road (7), recuperated cycle air channel (4) in heat exchange duct (24) after heat exchange, through outlet connecting pipe Road (14) is flowed in heat exchanger (12), realizes heat exchange by heat exchanger (12)；Check valve (9) is according to pressure transducer (16) Measured value realizes opening and closing, and when recuperated cycle air channel (4) pressure is less than threshold values, check valve (9) is opened, and nitrogen pot (10) is to heat exchange Nitrogen is supplemented, it is ensured that malleation, it is to avoid air leaks in circulation air path (4).