Magnesium metal smelting system taking hydrogen energy as fuel

Abstract

The utility model provides a magnesium metal smelting system taking hydrogen energy as fuel, which comprises a hydrogen energy and hydrogen energy combustion system, a rotary kiln, a magnesium metal smelting reduction furnace, a tail gas condensation recovery device, a waste heat power generation device and a steam-jet pump, and the hydrogen energy and hydrogen energy combustion system is respectively arranged on the rotary kiln and the magnesium metal smelting reduction furnace. Tail gas outlets of the rotary kiln and the magnesium metal smelting reduction furnace are connected with a tail gas inlet of the waste heat power generation device, a tail gas outlet of the waste heat power generation device is connected with an inlet of the tail gas condensation recovery device, and a water purification opening of the tail gas condensation recovery device is connected with a water inlet of the waste heat power generation device. A steam outlet of the waste heat power generation device is connected with the steam jet pump, a negative pressure suction opening of the steam jet pump is connected with a reduction tank in the magnesium metal smelting reduction furnace, and moisture in tail gas is recycled through the tail gas condensation recycling device and conveyed into the waste heat power generation device for waste heat power generation. The waste heat power generation device conveys high-pressure steam to the steam-jet pump, so that the reduction tank is kept in a negative pressure state.

Description

Technical Field

[0001] The utility model relates to the technical field of metal magnesium smelting, in particular to a metal magnesium smelting system using hydrogen energy as fuel. Background Art

[0002] Dolomite calcining rotary kiln and magnesium reduction furnace are the core equipment of magnesium production process. At present, magnesium reduction furnaces and rotary kilns used in China generally use water-coal slurry or coal powder as fuel for heating and reduction. After burning, water-coal slurry and coal powder will release a large amount of harmful substances, such as carbon monoxide, carbon dioxide, sulfur dioxide, smoke, radioactive dust, nitrogen oxides, etc., which put great pressure on the environment, are not energy-saving and environmentally friendly, and will also produce a large amount of wastewater and waste residue when processing these harmful substances. These harmful substances and wastewater and waste residue will seriously pollute the environment, not only posing a direct threat to human health, wasting water resources, but also causing acid rain and greenhouse effect and other problems. Utility Model Content

[0003] In view of this, it is necessary to provide a magnesium metal smelting system using hydrogen energy as fuel to solve the technical problems of environmental pollution and water resource waste in the prior art.

[0004] The technical solution adopted by the utility model to solve its technical problems is:

[0005] A magnesium smelting system using hydrogen energy as fuel, comprising a hydrogen energy and hydrogen energy combustion system, a rotary kiln for calcining dolomite, a magnesium smelting reduction furnace, a tail gas condensation recovery device, a waste heat power generation device, and a steam jet pump. The hydrogen energy and hydrogen energy combustion system comprises a first hydrogen burner and a second hydrogen burner, the first hydrogen burner and the second hydrogen burner are respectively arranged on the combustion ports of the rotary kiln and the magnesium smelting reduction furnace, the tail gas outlets of the rotary kiln and the magnesium smelting reduction furnace are connected to the tail gas inlet of the waste heat power generation device, the tail gas outlet of the waste heat power generation device is connected to the inlet of the tail gas condensation recovery device, the water purification port of the tail gas condensation recovery device is connected to the water inlet of the waste heat power generation device, the steam outlet of the waste heat power generation device is connected to the inlet of the steam jet pump, and the steam jet pump is arranged on the metal On the magnesium smelting reduction furnace, the negative pressure suction port of the steam jet pump is connected to the reduction tank in the magnesium smelting reduction furnace, and the calcined dolomite enters the reduction tank of the magnesium smelting reduction furnace for reduction reaction. The high-temperature tail gas discharged from the rotary kiln and the magnesium smelting reduction furnace passes through the waste heat power generation device and enters the tail gas condensation recovery device. The tail gas condensation recovery device is used to recover the moisture in the tail gas. The tail gas condensation recovery device transmits the recovered clean water to the waste heat power generation device. The waste heat power generation device uses the high-temperature tail gas discharged from the rotary kiln and the magnesium smelting reduction furnace to convert the clean water into high-pressure steam for waste heat power generation, and at the same time transmits the high-pressure steam to the steam jet pump, and uses the steam jet pump to continuously perform negative pressure suction on the reduction tank in the magnesium smelting reduction furnace, so that the reduction tank is kept under negative pressure for reduction reaction.

[0006] Preferably, the magnesium smelting system using hydrogen as fuel also includes a magnesium refining furnace, the discharge end of the reduction tank in the magnesium smelting reduction furnace is connected to the feed end of the magnesium refining furnace, and the magnesium refining furnace refines the crude magnesium generated by the reduction reaction in the reduction tank.

[0007] Preferably, the magnesium smelting system using hydrogen as fuel also includes a solid oxide fuel cell. The hydrogen output end of the hydrogen energy and hydrogen combustion system is connected to the hydrogen input end of the solid oxide fuel cell to transport hydrogen to the solid oxide fuel cell. The tail gas outlet of the solid oxide fuel cell is connected to the tail gas inlet of the waste heat power generation device. The high-temperature tail gas discharged by the solid oxide fuel cell enters the waste heat power generation device for waste heat utilization, and also enters the tail gas condensation recovery device for water recovery. The electricity generated by the solid oxide fuel cell and the waste heat power generation device is used to supply the rotary kiln or the magnesium refining furnace.

[0008] Preferably, the tail gas condensation recovery device comprises a tail gas cooling tower, a clarifier, a first circulation pump, and a second circulation pump. The tail gas outlet of the waste heat power generation device is connected to the inlet of the tail gas cooling tower. The clarifier is arranged below the tail gas cooling tower. The outlet of the tail gas cooling tower faces the clarifier. A sprayer is arranged on the top of the tail gas cooling tower. The input ends of the first circulation pump and the second circulation pump are respectively connected to the clean water outlet of the clarifier. The output ends of the first circulation pump and the second circulation pump are respectively connected to the sprayer and the water inlet of the waste heat power generation device. The first circulation pump transports the clean water in the clarifier to the The sprayer is used to spray and condense the exhaust gas discharged from the waste heat power generation device, so that the dust and condensed water in the exhaust gas discharged from the rotary kiln enter the clarification tank for precipitation. The second circulation pump transmits the clean water in the clarification tank to the waste heat power generation device. The waste heat power generation device uses the high-temperature exhaust gas discharged from the rotary kiln, the magnesium smelting reduction furnace and the solid oxide fuel cell to convert the clean water into high-pressure steam for waste heat power generation, and at the same time transmits the high-pressure steam to the steam jet pump, and uses the steam jet pump to continuously perform negative pressure suction on the reduction tank in the magnesium smelting reduction furnace to keep the reduction tank in a negative pressure state.

[0009] Preferably, the magnesium smelting system using hydrogen as fuel also includes a mixing and molding device, the feed port of the mixing and molding device is connected to the discharge port of the rotary kiln, and the discharge port of the mixing and molding device is connected to the feed end of the reduction tank in the magnesium smelting reduction furnace. The calcined dolomite is mixed and molded by the mixing and molding device, and then input into the reduction tank for reduction reaction.

[0010] Preferably, the mixing and molding device includes a mixer, a ball mill and a ball press, the feed port of the mixer is connected to the discharge port of the rotary kiln, the discharge port of the mixer is connected to the feed port of the ball mill, the discharge port of the ball mill is connected to the feed port of the ball press, and the discharge port of the ball press is connected to the feed end of the reduction tank in the metal magnesium smelting reduction furnace. After the calcined dolomite is mixed by the mixer, it enters the ball mill for mixing and grinding, enters the ball press for molding, and is finally input into the reduction tank for reduction reaction.

[0011] Preferably, a heat pipe air preheater is further arranged between the waste heat power generation device and the exhaust gas cooling tower, the exhaust gas outlet of the waste heat power generation device is connected to the exhaust gas inlet of the heat pipe air preheater, the exhaust gas outlet of the heat pipe air preheater is connected to the exhaust gas inlet of the exhaust gas cooling tower, the air heat exchange port of the heat pipe air preheater is respectively connected to the air inlet of the first hydrogen burner and the second hydrogen burner, the heat pipe air preheater uses the exhaust gas discharged from the waste heat power generation device to preheat the air entering each hydrogen burner to assist hydrogen combustion, and introduces the exhaust gas after heat exchange into the exhaust gas cooling tower, and uses the exhaust gas cooling tower to recover moisture and reduce dust in the exhaust gas.

[0012] Preferably, a sewage outlet is provided at the bottom of the clarification tank.

[0013] The utility model adopts the above technical solution, and its beneficial effect lies in: by respectively arranging hydrogen energy and hydrogen energy combustion system on the combustion port of rotary kiln and metal magnesium smelting reduction furnace, the tail gas outlet of rotary kiln and metal magnesium smelting reduction furnace is connected with the tail gas inlet of waste heat power generation device, the tail gas outlet of waste heat power generation device is connected with the inlet of tail gas condensation recovery device, the clean water outlet of tail gas condensation recovery device is connected with the water inlet of waste heat power generation device, the steam outlet of waste heat power generation device is connected with the inlet of steam jet pump, the steam jet pump is arranged on the metal magnesium smelting reduction furnace, and the steam jet pump is connected with the inlet of steam jet pump. The negative pressure suction port is connected to the reduction tank in the magnesium smelting reduction furnace. The high-temperature exhaust gas discharged from the rotary kiln and the magnesium smelting reduction furnace passes through the waste heat power generation device and then enters the exhaust gas condensation recovery device. The exhaust gas condensation recovery device is used to recover moisture and dust in the exhaust gas, and the clean water is transmitted to the waste heat power generation device. The waste heat power generation device uses the high-temperature exhaust gas to convert the clean water into high-pressure steam for waste heat power generation, and at the same time transmits the high-pressure steam to the steam jet pump. The steam jet pump is used to perform continuous negative pressure suction on the reduction tank in the magnesium smelting reduction furnace, so that the reduction tank is kept under negative pressure for reduction reaction. In this way, there is no need for external steam supply, nor is there any need to separately start other vacuum equipment such as screw vacuum pumps to maintain the negative pressure state in the reduction tank, thereby achieving self-sufficiency, energy recycling, saving water resources and energy saving and consumption reduction. In addition, the magnesium smelting system adopts the method of combining the high-temperature tail gas discharged from the rotary kiln and the magnesium smelting reduction furnace and inputting it into the waste heat power generation device for waste heat power generation, thereby improving the waste heat utilization rate and reducing the equipment and energy consumption costs. Moreover, using hydrogen as fuel will not emit harmful substances, which is beneficial to environmental protection and meets the current social requirements for environmental protection. Secondly, the hydrogen combustion temperature is easy to control, which is beneficial to improving the quality of dolomite calcination and the reduction rate and output of magnesium. For the magnesium smelting industry, it has great technical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of a magnesium metal smelting system using hydrogen as fuel.

[0015] Figure 2 This is a process flow chart of a magnesium metal smelting system using hydrogen as fuel.

[0016] In the figure: a first hydrogen burner 11, a second hydrogen burner 12, a hydrogen energy storage tank 14, a rotary kiln 20, a metal magnesium smelting reduction furnace 30, a reduction tank 301, a tail gas condensation recovery device 40, a tail gas cooling tower 401, a clarification tank 402, a first circulation pump 403, a second circulation pump 404, a sprayer 405, a waste heat power generation device 50, a waste heat steam boiler 501, a steam jet pump 60, a solid oxide fuel cell 70, and a heat pipe air preheater 80. DETAILED DESCRIPTION

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Please see Figure 1 or Figure 2The embodiment of the utility model provides a magnesium smelting system using hydrogen energy as fuel, including a hydrogen energy and hydrogen energy combustion system, a rotary kiln 20 for calcining dolomite, a magnesium smelting reduction furnace 30, a tail gas condensation recovery device 40, a waste heat power generation device 50, and a steam jet pump 60. The hydrogen energy and hydrogen energy combustion system includes a first hydrogen burner 11 and a second hydrogen burner 12 and a hydrogen energy storage tank 14 for providing hydrogen. The first hydrogen burner 11 and the second hydrogen burner 12 are respectively arranged on the combustion ports of the rotary kiln 20 and the magnesium smelting reduction furnace 30. The first hydrogen burner 11 and the second hydrogen burner 12 are respectively arranged on the combustion ports of the rotary kiln 20 and the magnesium smelting reduction furnace 30. The burner 12 is connected to the hydrogen output end of the hydrogen energy storage tank 14 respectively, and hydrogen is provided through the hydrogen energy storage tank 14. The tail gas outlets of the rotary kiln 20 and the magnesium smelting reduction furnace 30 are respectively connected to the tail gas inlet of the waste heat power generation device 50. The tail gas outlet of the waste heat power generation device 50 is connected to the inlet of the tail gas condensation recovery device 40. The clean water outlet of the tail gas condensation recovery device 40 is connected to the water inlet of the waste heat power generation device 50. The steam outlet of the waste heat power generation device 50 is connected to the inlet of the steam jet pump 60. The steam jet pump 60 is arranged on the magnesium smelting reduction furnace 30. The steam jet pump 60 The negative pressure suction port is connected to the reduction tank 301 in the magnesium smelting reduction furnace 30. The calcined dolomite enters the reduction tank 301 of the magnesium smelting reduction furnace 30 for reduction reaction. During the production process of the magnesium smelting reduction furnace 30 and the rotary kiln 20, the high-temperature tail gas discharged enters the waste heat power generation device 50 for waste heat power generation and then enters the tail gas condensation recovery device 40. The tail gas condensation recovery device 40 is used to recover the moisture in the tail gas. The high-temperature tail gas discharged from the magnesium smelting reduction furnace 30 and the rotary kiln 20 is the first hydrogen burner 11 and the second hydrogen burner 12 in the magnesium smelting reduction furnace. The tail gas generated by burning hydrogen in the rotary kiln 30 and the rotary kiln 20 is recovered by the tail gas condensation recovery device 40, and the recovered clean water is transmitted to the waste heat power generation device 50. The waste heat power generation device 50 uses the high-temperature tail gas discharged from the rotary kiln 20 and the magnesium metal smelting reduction furnace 30 to convert the clean water into high-pressure steam, and uses the high-pressure steam to generate waste heat power. At the same time, a part of the high-pressure steam is transmitted to the steam jet pump 60 to drive the steam jet pump 60 to continuously perform negative pressure suction on the reduction tank 301 in the magnesium metal smelting reduction furnace 30, so that the reduction tank 301 is kept under negative pressure to perform reduction reaction. In this way, the negative pressure state in the reduction tank 301 can be maintained without external steam supply, which saves water resources, achieves self-sufficiency, energy recycling and energy saving and consumption reduction. In addition, the magnesium smelting system combines the high-temperature tail gas discharged from the rotary kiln 20 and the magnesium smelting reduction furnace 30 and inputs it into the waste heat power generation device 50 for waste heat power generation, thereby improving the waste heat utilization rate and reducing equipment costs. Moreover, using hydrogen as fuel will not emit harmful substances, which is beneficial to environmental protection and meets the current social requirements for environmental protection.

[0019] Specifically, the tail gas condensation recovery device 40 includes a tail gas cooling tower 401, a clarifier 402, a first circulation pump 403, and a second circulation pump 404. The tail gas outlet of the waste heat power generation device 50 is connected to the inlet of the tail gas cooling tower 401. The clarifier 402 is arranged below the tail gas cooling tower 401, and the outlet of the tail gas cooling tower 401 is directly opposite to the clarifier 402. A sprayer 405 is arranged on the top of the tail gas cooling tower 401. The input ends of the first circulation pump 403 and the second circulation pump 404 are respectively connected to the clean water outlet of the clarifier 402, the output end of the first circulation pump 403 is connected to the sprayer 405, and the output end of the second circulation pump 404 is connected to the water inlet of the waste heat power generation device 50. The high-pressure steam output of the waste heat power generation device 50 is connected to the water inlet of the waste heat power generation device 50. The outlet is connected to the steam inlet of the steam jet pump 60. During the production process of the magnesium smelting reduction furnace 30 and the rotary kiln 20, the high-temperature exhaust gas discharged passes through the waste heat power generation device 50 and enters the exhaust gas cooling tower 401. The first circulation pump 403 transmits clean water to the sprayer 405. The sprayer 405 cools and condenses the exhaust gas entering the exhaust gas cooling tower 401 to recover the water vapor in the exhaust gas. The recovered water enters the clarification tank 402 and is collected and clarified by the clarification tank 402. The clean water clarified by the clarification tank 402 is used by the sprayer 405 and the waste heat power generation device 50. In addition, during the spraying process, the dust generated by the calcination of dolomite contained in the exhaust gas will also enter the clarification tank 402 with the spraying water under the action of spraying, thereby playing a dust removal role.

[0020] The second circulation pump 404 transmits the clean water in the clarification tank 402 to the waste heat power generation device 50. The waste heat power generation device 50 is a device that uses waste heat in industrial production to generate electricity. It is composed of a blower, a waste heat steam boiler 501, an air turbine, a transmission, a generator, etc. The clean water in the clarification tank 402 enters the waste heat steam boiler 501. The waste heat steam boiler 501 uses the high-temperature tail gas discharged from the rotary kiln 20 and the magnesium metal smelting reduction furnace 30 to convert the clean water into high-pressure steam, which is then converted into mechanical energy through the air turbine, and finally converted into electrical energy through the transmission and the generator to generate waste heat electricity. The electricity generated can be used by the magnesium metal smelting system. At the same time, the waste heat steam The high-pressure steam converted by the boiler 501 is also used to drive the steam jet pump 60. The steam jet pump 60 is a kind of high-pressure steam as a power source. The high-pressure steam is used to generate a high-speed steam flow at the nozzle outlet of the steam jet pump 60. The nozzle outlet is provided with the above-mentioned negative pressure suction port. The high-speed steam flow expands after passing through the nozzle, the speed increases, and the pressure decreases, thereby forming a negative pressure near the nozzle outlet of the steam jet pump 60, so as to achieve the purpose of sucking gas or forming a vacuum. The working principle of the steam jet pump 60 is used to continuously perform negative pressure suction on the reduction tank 301 in the metal magnesium smelting reduction furnace 30, so that materials such as magnesium oxide and ferrosilicon in the reduction tank 301 undergo reduction reaction under vacuum conditions.

[0021] Furthermore, a sewage outlet is provided at the bottom of the clarification tank 402, and the sewage outlet is in a normally closed state. During the long-term operation of the rotary kiln 20, dust and impurities generated by the calcination of dolomite will settle at the bottom of the clarification tank 402. The sewage outlet is provided to facilitate the cleaning of the clarification tank 402.

[0022] It should be noted that in order to ensure the normal operation of the magnesium smelting system, water supply pipes are respectively provided at the input ends of the first circulation pump 403 and the second circulation pump 404, and the inlets of the water supply pipes are connected to the external water supply pipes. When the magnesium smelting system is in the early stage of startup or when there is insufficient water in the clarification tank 402, water can be supplied through the external water supply pipes.

[0023] Please see Figure 2 Furthermore, the magnesium smelting system using hydrogen as fuel also includes a mixing and forming device, which includes a mixer, a ball mill, a briquette press and a jaw crusher. The feed port of the mixer is connected to the discharge port of the rotary kiln 20, the discharge port of the mixer is connected to the feed port of the ball mill, the discharge port of the ball mill is connected to the feed port of the briquette press, and the discharge port of the briquette press is connected to the feed end of the reduction tank 301 in the magnesium smelting reduction furnace 30. The discharge port of the jaw crusher is connected to the feed port of the mixer. The jaw crusher is used to crush ferrosilicon, and the mixer is used to mix the raw materials for smelting magnesium. The dolomite calcined by the rotary kiln 20, the ferrosilicon and fluorite crushed by the jaw crusher enter the mixer for mixing, and then are ground by the ball mill and then enter the ball press for molding. The molded raw materials are input into the reduction tank 301 of the magnesium smelting reduction furnace 30 for reduction reaction to generate crude magnesium.

[0024] Please see Figure 2 Furthermore, the magnesium smelting system using hydrogen as fuel also includes a magnesium refining furnace. The discharge end of the reduction tank 301 in the magnesium smelting reduction furnace 30 is connected to the feed end of the magnesium refining furnace. The crude magnesium generated by the magnesium smelting reduction reaction enters the magnesium refining furnace, and the crude magnesium is refined by the magnesium refining furnace.

[0025] Please see Figure 1 or Figure 2Furthermore, the magnesium smelting system using hydrogen as fuel also includes a solid oxide fuel cell 70, which is a fully solid-state chemical power generation device (SOFC). The hydrogen output end of the hydrogen energy storage tank 14 is connected to the hydrogen input end of the solid oxide fuel cell 70 to transport hydrogen to the solid oxide fuel cell 70. The tail gas outlet of the solid oxide fuel cell 70 is connected to the tail gas inlet of the waste heat power generation device 50. The solid oxide fuel cell 70 uses hydrogen as fuel to generate electricity, and the generated electricity is used for the magnesium smelting system. The high-temperature tail gas generated during the power generation process is discharged into the waste heat power generation device 50 for waste heat power generation utilization. After the waste heat power generation is utilized, the water in the tail gas is recovered through the tail gas condensation recovery device 40 to supplement the heat source and water source required by the waste heat power generation device 50, thereby improving the power generation efficiency of the waste heat power generation device 50, realizing energy complementarity and recycling, and further reducing energy consumption and environmental pressure.

[0026] Please continue to see Figure 1 or Figure 2 Furthermore, a heat pipe air preheater 80 is also arranged between the waste heat power generation device 50 and the tail gas cooling tower 401, the tail gas outlet of the waste heat power generation device 50 is connected to the tail gas inlet of the heat pipe air preheater 80, the tail gas outlet of the heat pipe air preheater 80 is connected to the tail gas inlet of the tail gas cooling tower 401, the air heat exchange port of the heat pipe air preheater 80 is respectively connected to the air inlet of the first hydrogen burner 11 and the second hydrogen burner 12, the heat pipe air preheater 80 uses the tail gas discharged from the waste heat power generation device 50 to preheat the air entering each hydrogen burner to assist hydrogen combustion, and introduces the tail gas after heat exchange into the tail gas cooling tower 401, and uses the tail gas cooling tower 401 to recover moisture and reduce dust in the tail gas.

[0027] The heat pipe air preheater 80 is an air heat exchange device, which uses heat pipe technology to recover waste heat in the exhaust gas discharged from the waste heat power generation device 50. The exhaust gas discharged from the waste heat power generation device 50 is the exhaust gas generated by the combustion of hydrogen in the rotary kiln 20, the magnesium metal smelting reduction furnace 30 and the solid oxide fuel cell 70. The exhaust gas will contain a large amount of moisture. After the exhaust gas is used for waste heat power generation by the waste heat power generation device 50, it is used for secondary waste heat utilization by the heat pipe air preheater 80 to assist hydrogen combustion, which has the effect of energy saving. In addition, the secondary waste heat utilization by the heat pipe air preheater 80 can further cool and dissipate the exhaust gas, which is beneficial to the exhaust gas cooling tower 401 to condense and recover moisture in the exhaust gas.

[0028] The magnesium smelting system using hydrogen as fuel uses hydrogen as fuel during the production process, and will not discharge harmful substances, which is beneficial to environmental protection and meets the current social requirements for environmental protection. Secondly, the combustion temperature of hydrogen is high and the temperature is easy to control, which is beneficial to improving the quality of dolomite calcination and the reduction rate and output of magnesium. For the magnesium smelting industry, it has great technical application value; and the magnesium smelting system adopts the high-temperature tail gas discharged by the rotary kiln 20, the magnesium smelting reduction furnace 30, and the solid oxide fuel cell 70 to be combined and input into the waste heat power generation device 50, and the waste heat power generation device 50 is used to generate waste heat, improve the waste heat utilization rate, and reduce equipment and energy costs; the tail gas condensation recovery device 40 is used to recover and recycle the water in the tail gas after the hydrogen is burned, saving water resources; the high-pressure steam converted by the waste heat power generation device 50 is used to drive the steam jet pump 60 to maintain the negative pressure state in the reduction tank 301, and no external steam is required, and no other vacuum equipment such as the screw vacuum pump needs to be started separately, so as to achieve self-sufficiency, energy recycling and energy saving and consumption reduction, and reduce production costs. In addition, the steam jet pump 60 has good working stability and can provide continuous and stable negative pressure for the reduction tank 301, which is convenient for discharging by-products and impurities generated in the reaction process of the reduction tank 301, and is beneficial for the reduction reaction of materials such as magnesium oxide and ferrosilicon in the reduction tank 301 under stable vacuum conditions, which helps to improve the purity of metallic magnesium. Compared with other vacuum equipment such as screw vacuum pumps used in the prior art, the steam jet pump 60 has a simple structure, does not require electricity consumption, does not require maintenance, avoids mechanical failures leading to furnace shutdowns, does not require the addition of lubricants for maintenance, and can avoid lubricant leakage from posing a pollution threat to the materials in the reduction tank 301.

[0029] The above disclosure is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims

1. A magnesium smelting system using hydrogen as fuel, characterized in that: The invention comprises a hydrogen energy and hydrogen energy combustion system, a rotary kiln for calcining dolomite, a magnesium smelting reduction furnace, a tail gas condensation recovery device, a waste heat power generation device, and a steam jet pump. The hydrogen energy and hydrogen energy combustion system comprises a first hydrogen burner and a second hydrogen burner. The first hydrogen burner and the second hydrogen burner are respectively arranged on the combustion ports of the rotary kiln and the magnesium smelting reduction furnace. The tail gas outlets of the rotary kiln and the magnesium smelting reduction furnace are connected to the tail gas inlet of the waste heat power generation device. The tail gas outlet of the waste heat power generation device is connected to the inlet of the tail gas condensation recovery device. The water purification port of the tail gas condensation recovery device is connected to the water inlet of the waste heat power generation device. The steam outlet of the waste heat power generation device is connected to the inlet of the steam jet pump. The negative pressure suction port of the steam jet pump is connected to the reduction tank in the magnesium smelting reduction furnace. The high-temperature exhaust gas discharged from the rotary kiln and the magnesium smelting reduction furnace passes through the waste heat power generation device and then enters the exhaust gas condensation recovery device. The exhaust gas condensation recovery device is used to recover the moisture in the exhaust gas. The exhaust gas condensation recovery device transmits the recovered clean water to the waste heat power generation device. The waste heat power generation device utilizes the high-temperature exhaust gas discharged from the rotary kiln and the magnesium smelting reduction furnace to convert the clean water into high-pressure steam for waste heat power generation, and at the same time transmits the high-pressure steam to the steam jet pump, and utilizes the steam jet pump to perform continuous negative pressure suction on the reduction tank in the magnesium smelting reduction furnace, so that the reduction tank is kept in a negative pressure state for reduction reaction.

2. The magnesium smelting system using hydrogen as fuel as claimed in claim 1, characterized in that: It also includes a magnesium refining furnace, wherein the discharge end of the reduction tank in the magnesium smelting reduction furnace is connected to the feed end of the magnesium refining furnace, and the magnesium refining furnace refines the crude magnesium generated by the reduction reaction in the reduction tank.

3. The magnesium smelting system using hydrogen as fuel as claimed in claim 2, characterized in that: It also includes a solid oxide fuel cell. The hydrogen output end of the hydrogen energy and hydrogen energy combustion system is connected to the hydrogen input end of the solid oxide fuel cell to transport hydrogen to the solid oxide fuel cell. The tail gas outlet of the solid oxide fuel cell is connected to the tail gas inlet of the waste heat power generation device. The high-temperature tail gas discharged by the solid oxide fuel cell enters the waste heat power generation device for waste heat utilization, and also enters the tail gas condensation recovery device for water recovery. The electricity generated by the solid oxide fuel cell and the waste heat power generation device is used to supply a rotary kiln or a magnesium metal refining furnace.

4. The magnesium smelting system using hydrogen as fuel as claimed in claim 1, characterized in that: The tail gas condensation recovery device comprises a tail gas cooling tower, a clarifier, a first circulation pump, and a second circulation pump. The tail gas outlet of the waste heat power generation device is connected to the inlet of the tail gas cooling tower. The clarifier is arranged below the tail gas cooling tower. The outlet of the tail gas cooling tower faces the clarifier. A sprayer is arranged on the top of the tail gas cooling tower. The first circulation pump and the input end of the first circulation pump are respectively connected to the clean water outlet of the clarifier. The output end of the first circulation pump and the first circulation pump are respectively connected to the sprayer and the water inlet of the waste heat power generation device. The first circulation pump transports the clean water in the clarifier to the water inlet of the waste heat power generation device. The exhaust gas discharged from the waste heat power generation device is sprayed and condensed by the sprayer, so that the dust in the exhaust gas and the condensed water enter the clarification tank for precipitation. The second circulation pump transmits the clean water in the clarification tank to the waste heat power generation device. The waste heat power generation device uses the high-temperature exhaust gas discharged by the rotary kiln, the magnesium smelting reduction furnace and the solid oxide fuel cell to convert the clean water into high-pressure steam for waste heat power generation, and at the same time transmits the high-pressure steam to the steam jet pump, and uses the steam jet pump to continuously perform negative pressure suction on the reduction tank in the magnesium smelting reduction furnace to keep the reduction tank in a negative pressure state.

5. The magnesium smelting system using hydrogen as fuel as claimed in claim 1, characterized in that: It also includes a mixing and molding device, the feed port of the mixing and molding device is connected to the discharge port of the rotary kiln, and the discharge port of the mixing and molding device is connected to the feed end of the reduction tank in the magnesium smelting reduction furnace. The calcined dolomite is mixed and molded by the mixing and molding device, and then input into the reduction tank for reduction reaction.

6. The magnesium smelting system using hydrogen as fuel as claimed in claim 5, characterized in that: The mixing and forming device comprises a mixer, a ball mill and a ball press. The feed port of the mixer is connected to the discharge port of the rotary kiln, the discharge port of the mixer is connected to the feed port of the ball mill, the discharge port of the ball mill is connected to the feed port of the ball press, and the discharge port of the ball press is connected to the feed end of the reduction tank in the metal magnesium smelting reduction furnace. After the calcined dolomite is mixed by the mixer, it sequentially enters the ball mill for mixing and grinding, enters the ball press for forming, and is finally input into the reduction tank for reduction reaction.

7. The magnesium smelting system using hydrogen as fuel as claimed in claim 4, characterized in that: A heat pipe air preheater is also arranged between the waste heat power generation device and the tail gas cooling tower. The tail gas outlet of the waste heat power generation device is connected to the tail gas inlet of the heat pipe air preheater, and the tail gas outlet of the heat pipe air preheater is connected to the tail gas inlet of the tail gas cooling tower. The air heat exchange port of the heat pipe air preheater is respectively connected to the air inlet of the first hydrogen burner and the second hydrogen burner. The heat pipe air preheater uses the tail gas discharged from the waste heat power generation device to preheat the air entering each hydrogen burner to assist hydrogen combustion, and introduces the tail gas after heat exchange into the tail gas cooling tower, and uses the tail gas cooling tower to recover moisture and reduce dust in the tail gas.

8. The magnesium smelting system using hydrogen as fuel as claimed in claim 4, characterized in that: A sewage outlet is arranged at the bottom of the clarification tank.

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