A system for converting sodium source into heat energy and hydrogen online

Abstract

The invention discloses a system for converting a sodium source into heat energy and hydrogen online. Before the reaction, hydrogen is used to fill the reactor. After liquid sodium and water vapor are injected, the water vapor and liquid sodium are contacted to generate a combustion reaction to generate hydrogen and sodium hydroxide. The water vapor that does not participate in the reaction absorbs heat to form high-temperature water vapor with a higher temperature. The temperature of the mixed gas of hydrogen and high-temperature water vapor after passing through the heat exchanger is lower than 70°C. The high-temperature water vapor is condensed into water and flows back to the bottom of the reactor. The hydrogen is discharged from the hydrogen collection pipe through the pressure reducing valve. While the combustion reaction is in progress, the drain valve is controlled to make the height of the sodium hydroxide solution lower than the outlet end of the water vapor injection pipe. The safety hazards such as explosion due to the sodium-water reaction in the prior art are avoided, and a higher temperature heat source and hydrogen can be formed and the operating cost can be reduced.

Description

Technical Field

[0001] The invention relates to an energy generation system, in particular to a system for online conversion of a sodium source into thermal energy and hydrogen. Background Art

[0002] Energy is the material basis for the development of human society, economy and science and technology. Building an efficient and low-carbon renewable energy system is the fundamental way to solve the dual crises of global energy depletion and environmental pollution. Therefore, environmentally friendly energy such as hydropower, wind power, photovoltaic power generation and hydrogen energy are developing rapidly. However, while accelerating the development and utilization of clean energy, hydropower, wind power and photovoltaic power generation have encountered problems such as difficulty in storage, transmission and consumption.

[0003] Sodium has a wide range of sources and abundant reserves on Earth, accounting for as much as 2.64% of the reserves in the earth's crust; Sodium has a high energy density. When metallic sodium undergoes an oxidation reaction, it can release a large amount of heat. The energy released per ton of sodium is equivalent to the calorific value of 0.4 tons of standard coal, which is twice the calorific value of hydrogen; The sodium production process is mature, and sodium is prepared industrially by electrolysis of NaCl or NaOH. The production rate of metallic sodium is controlled by adjusting parameters such as electrolysis conditions; Sodium storage and transportation technology is very mature, and the cost is equivalent to 1 / 3 of high-pressure hydrogen. In particular, sodium reacts with water to produce hydrogen and sodium hydroxide (industrial basic alkali). If sodium is used as a raw material to generate hydrogen, it can solve problems such as energy storage and transmission. However, sodium has strong reducing properties and reacts violently when in contact with water in the air. The existing methods of sodium-water reaction are as follows:

[0004] 1. Inject liquid sodium (liquid sodium) into a reaction vessel containing a large amount of sodium hydroxide solution to achieve the reaction of sodium and water. The reaction of sodium and water will release a large amount of heat, and the heat generated will evaporate the water. Therefore, the reaction products are sodium hydroxide solution, hydrogen and water vapor. The hydrogen is mixed with water vapor and discharged from the chimney after being treated by a demister, a dryer and a high-efficiency filter. On the one hand, the temperature of the reaction system is not high, and the heat is difficult to recover; on the other hand, the volume expansion of water from liquid to gas poses a safety hazard of explosion. Therefore, it is necessary to pay close attention to the concentration of sodium hydroxide solution and maintain it at about 30% to avoid explosions caused by low concentration of alkaline solution and fast reaction speed. Therefore, this method has a slow reaction speed and low efficiency, and is only suitable for digesting waste metal sodium.

[0005] 2. A suitable amount of water and kerosene are placed in a reactor with an outlet for alkali solution to form two phases of oil and water. Sodium reacts rapidly when it contacts water. The generated water vapor rises from the oil-water interface due to its much lower density than kerosene and no longer reacts with sodium. The generated hydrogen passes through the kerosene layer and is cooled, collected and recycled. Although the reaction of sodium and water can be guaranteed to be safe and the target product - hydrogen can be obtained, the kerosene provided dissipates the heat energy generated by the reaction of metallic sodium and water, causing heat loss. On the other hand, a small amount of organic impurities in the kerosene will be mixed into the generated sodium hydroxide solution. The alkali solution needs to be purified later, which is cumbersome and increases the cost. Summary of the invention

[0006] The present invention aims to solve the above-mentioned technical problems existing in the prior art and provides a system for online conversion of a sodium source into heat energy and hydrogen.

[0007] The technical solution of the present invention is: a system for converting a sodium source into heat energy and hydrogen online, which is provided with a closed reactor, a lye discharge pipe at the bottom of the reactor, a drain valve on the lye discharge pipe, a hydrogen collecting pipe at the upper end of the reactor, a pressure reducing valve on the hydrogen collecting pipe, a heat exchanger, a temperature sensor and a pressure sensor in the reactor, a liquid sodium injection pipe and a water vapor injection pipe at the bottom of the reactor, a liquid sodium injection check valve on the liquid sodium injection pipe, a water vapor injection check valve on the water vapor injection pipe, the liquid sodium injection pipe and the water vapor injection pipe are both located in the reactor and the outlet end of the liquid sodium injection pipe is located above the outlet end of the water vapor injection pipe; the heat exchanger is a heat exchanger arranged up and down with the refrigerant inlet at the top and the refrigerant outlet at the bottom, a heat exchange valve is provided at the refrigerant inlet, and the temperature sensor is located at the upper end of the heat exchanger;

[0008] Follow the steps below:

[0009] Step 1. Fill the reactor with hydrogen;

[0010] Step 2. Open the heat exchange valve;

[0011] Step 3. Open the liquid sodium injection check valve and the water vapor injection check valve;

[0012] Step 4. The injected liquid sodium undergoes a combustion reaction after contacting with water vapor to generate hydrogen, high-temperature water vapor and sodium hydroxide; the heat exchange valve, the liquid sodium injection check valve and the water vapor injection check valve are controlled so that the temperature of the hydrogen and the high-temperature water vapor after passing through the heat exchanger is lower than 70°C, and the hydrogen is discharged from the hydrogen collection pipe through the pressure reducing valve, and the pressure reducing valve adjusts the pressure in the reactor to 0.1-10Mpa; the high-temperature water vapor condenses to the bottom of the water flow reactor after passing through the heat exchanger, and the drain valve is controlled so that the height of the sodium hydroxide solution is lower than the outlet end of the water vapor injection pipe.

[0013] The preferred technical solution is that the outlet end of the liquid sodium injection pipe and the outer periphery of the outlet end of the water vapor injection pipe

[0014] A combustion chamber with upper and lower openings.

[0015] The preferred technical solution is that a liquid level sensor is provided below the water vapor injection pipe.

[0016] The present invention uses hydrogen to fill the reactor before the reaction, so that the reactor is in an oxygen-free state. When liquid sodium and water vapor are injected into the reactor, the water vapor and liquid sodium come into contact and a combustion reaction occurs to generate hydrogen and sodium hydroxide. The water vapor that does not participate in the reaction absorbs heat to form high-temperature water vapor with a higher temperature. The temperature of the mixed gas of hydrogen and high-temperature water vapor after passing through the heat exchanger is lower than 70°C, and the high-temperature water vapor is condensed into water and flows back to the bottom of the reactor. The hydrogen is discharged from the hydrogen collection pipe through the pressure reducing valve. While the combustion reaction is in progress, the drain valve is controlled to make the height of the sodium hydroxide solution lower than the outlet end of the water vapor injection pipe. Compared with the prior art, the present invention has the following advantages:

[0017] 1. Water vapor is directly used as the reaction raw material, avoiding the safety hazards such as explosion caused by volume expansion due to the phase change of water into water vapor when heated in the existing technology;

[0018] 2. After being heated, the water vapor will further heat up to form high-temperature gas, which will exchange heat with the cold enzyme in the heat exchanger to form a higher temperature heat source, meeting the needs of industrial production for high-temperature heat sources. At the same time, the water vapor will condense to form water, which is effectively separated from the hydrogen.

[0019] 3. The product (hydrogen) that does not react with water vapor and sodium is used as the protective gas to ensure the safe combustion of the sodium-water reaction.

[0020] 4. No need to add kerosene, which can avoid the purification of sodium hydroxide solution, simple operation and reduced operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of embodiment 1 of the present invention.

[0022] Figure 2 It is a structural diagram of embodiment 2 of the present invention. DETAILED DESCRIPTION Example 1

[0023] A system for converting a sodium source into heat energy and hydrogen online according to the present invention is as follows: Figure 1As shown, a closed reactor 1 is provided, a lye discharge pipe 2 is provided at the bottom of the reactor 1, a drain valve 2-1 is provided on the lye discharge pipe 2, a hydrogen collecting pipe 3 is provided at the upper end of the reactor 1, a pressure reducing valve 3-1 is provided on the hydrogen collecting pipe 3, a heat exchanger 4, a temperature sensor 5 and a pressure sensor 6 are provided in the reactor 1, a liquid sodium injection pipe 7 and a water vapor injection pipe 8 are provided at a certain height below the bottom of the reactor 1, a liquid sodium injection check valve 7-1 is provided on the liquid sodium injection pipe 7, and a water vapor injection check valve 8-1 is provided on the water vapor injection pipe 8, the liquid sodium injection pipe 7 and the water vapor injection pipe 8 are both located in the reactor 1 and the outlet end of the liquid sodium injection pipe 7 is located above the outlet end of the water vapor injection pipe 8, so that the rising water vapor is fully contacted with the liquid sodium to react; the heat exchanger 4 is a single-stage or multi-stage heat exchanger arranged up and down, with the refrigerant inlet at the top and the refrigerant outlet at the bottom, and can be in any form such as serpentine or plate-shaped, but it is necessary to ensure sufficient heat exchange with hydrogen and water vapor. A heat exchange valve 4-1 is provided at the refrigerant inlet, and a temperature sensor 5 is located at the upper end of the heat exchanger 4 to monitor the temperature of the water vapor after passing through the heat exchanger 4;

[0024] Follow the steps below:

[0025] Step 1. Fill the reactor 1 with hydrogen through the hydrogen collecting pipe 3 of the reactor 1. The reactor 1 may be filled with water first, and then hydrogen is injected and the drain valve 2-1 is opened. When all the water flows out, the reactor 1 is filled with hydrogen;

[0026] Step 2. Open the heat exchange valve 4-1 and inject refrigerant into the heat exchanger 4. The refrigerant is mineral oil, low-temperature gas, etc. that can fully carry heat;

[0027] Step 3. Open the liquid sodium injection check valve 7-1 and the water vapor injection check valve 8-1, and inject liquid sodium and water vapor into the reactor 1;

[0028] Step 4. The injected liquid sodium undergoes a combustion reaction after contacting with water vapor to generate hydrogen, high-temperature water vapor and sodium hydroxide; the heat exchange valve 4-1, the liquid sodium injection check valve 7-1 and the water vapor injection check valve 8-1 are controlled so that the temperature of the hydrogen and the high-temperature water vapor after passing through the heat exchanger 4 is lower than 70°C, and the hydrogen is discharged from the hydrogen collecting pipe 3 through the pressure reducing valve 3-1, and the pressure reducing valve 3-1 adjusts the pressure in the reactor 1 to 0.1-10Mpa; the high-temperature water vapor condenses into water after passing through the heat exchanger 4 and flows back to the bottom of the reactor 1, and the drain valve 2-1 is controlled at the same time so that the height of the sodium hydroxide solution is lower than the outlet end of the water vapor injection pipe 8. Example 2

[0029] A system for converting a sodium source into heat energy and hydrogen online according to the present invention is as follows: Figure 2As shown, the basic structure and method are the same as those of Example 1, and the difference from Example 1 is that the outlet end of the liquid sodium injection pipe 7 and the outlet end of the water vapor injection pipe 8 are located on one radial side of the reactor 1 and there is a combustion chamber 9 with upper and lower openings on the periphery of the two outlet ends, and the combustion chamber 9 is made of high temperature resistant material. At this time, the heat exchanger 4 can be tilted downward as a whole, so that the lower end is located on the other radial side of the combustion chamber 9. The combustion chamber 9 can be set to prevent water vapor from escaping, so that the liquid sodium and water vapor can fully react in the combustion chamber 9. On the other hand, after the water vapor is condensed into water through the heat exchanger 4, it can flow back to the bottom surface of the reactor 1 along the outer surface of the heat exchanger 4, avoiding flowing into the combustion chamber 9 to react with the liquid sodium.

[0030] The drain valve 2-1, the pressure reducing valve 3-1, the liquid sodium injection check valve 7-1 and the water vapor injection check valve 8-1 can all be electronic valves, which are controlled by the controller according to the signals of the temperature sensor 5 and the pressure sensor 6. A liquid level sensor 10 connected to the controller can be arranged below the water vapor injection pipe 8 to monitor the height of the alkali solution at all times to prevent the height of the sodium hydroxide solution from being higher than the outlet end of the water vapor injection pipe 8, that is, to prevent the water in the sodium hydroxide solution from reacting with the sodium.

Claims

1. A system for online conversion of a sodium source into heat energy and hydrogen, comprising a closed reactor (1), a lye discharge pipe (2) at the bottom of the reactor (1), a drain valve (2-1) on the lye discharge pipe (2), a hydrogen collection pipe (3) at the top of the reactor (1), a pressure reducing valve (3-1) on the hydrogen collection pipe (3), a heat exchanger (4), a temperature sensor (5) and a pressure sensor (6) in the reactor (1), characterized in that: A liquid sodium injection pipe (7) and a water vapor injection pipe (8) are provided below the reactor (1); a liquid sodium injection check valve (7-1) is provided on the liquid sodium injection pipe (7); a water vapor injection check valve (8-1) is provided on the water vapor injection pipe (8); the liquid sodium injection pipe (7) and the water vapor injection pipe (8) are both located inside the reactor (1); and the outlet end of the liquid sodium injection pipe (7) is located above the outlet end of the water vapor injection pipe (8); the heat exchanger (4) is a heat exchanger arranged up and down with the refrigerant inlet at the top and the refrigerant outlet at the bottom; a heat exchange valve (4-1) is provided at the refrigerant inlet; and a temperature sensor (5) is located at the upper end of the heat exchanger (4); Follow the steps below: Step 1. Filling the reactor (1) with hydrogen; Step 2. Open the heat exchange valve (4-1); Step 3. Open the liquid sodium injection check valve (7-1) and the water vapor injection check valve (8-1); Step 4. The injected liquid sodium and water vapor undergo a combustion reaction after contact, generating hydrogen, high-temperature water vapor and sodium hydroxide; controlling the heat exchange valve (4-1), the liquid sodium injection check valve (7-1) and the water vapor injection check valve (8-1) so that the temperature of the hydrogen and the high-temperature water vapor after passing through the heat exchanger (4) is lower than 70° C., and the hydrogen is discharged from the hydrogen collection pipe (3) through the pressure reducing valve (3-1), and the pressure reducing valve (3-1) adjusts the pressure in the reactor (1) to 0.1-10 MPa; the high-temperature water vapor condenses into water after passing through the heat exchanger (4) and flows back to the bottom of the reactor (1), and controlling the drain valve (2-1) so that the height of the sodium hydroxide solution is lower than the outlet end of the water vapor injection pipe (8).

2. The system for online conversion of sodium source into heat energy and hydrogen according to claim 1, characterized in that: A combustion chamber (9) with upper and lower openings is provided on the periphery of the outlet end of the liquid sodium injection pipe (7) and the outlet end of the water vapor injection pipe (8).

3. The system for online conversion of sodium source into heat energy and hydrogen according to claim 1, characterized in that: A liquid level sensor (10) is provided below the water vapor injection pipe (8).

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