CN115557468A - Method for extracting bromine from brine - Google Patents

Abstract

The invention discloses a method for extracting bromine in brine, which is realized by bromine extraction equipment. The acidified brine and chlorine gas are mixed to form free bromine, which is sent to the absorption tower by air in the blowing tower, and the free bromine in the absorption tower After entering the sulfur dioxide aqueous solution, the absorption liquid containing hydrobromic acid is formed, and the heat generated by sulfur combustion is used to heat the absorption liquid. The absorption liquid enters the distillation tower and reacts with chlorine gas to form hydrogen chloride and free bromine. The free bromine is under the action of the heat of the absorption liquid. It is evaporated into bromine vapor, and the air flowing out from the absorption tower enters the blowing tower to blow bromine. The above method fully utilizes the heat generated by sulfur combustion to produce bromine without using an external heat source, and has a good energy-saving effect.

Description

A kind of method for extracting bromine in brine

technical field

The invention relates to a method for extracting bromine in brine, in particular to an energy-saving method for extracting bromine in brine.

Background technique

In the current industrial bromine production, there are mainly two methods to extract bromine, namely steam distillation and air blowing method, and the air blowing method is currently the most important method for producing bromine in China. In the process of producing bromine by the air blowing method, there are two absorption and conversion methods, one is the acid absorption using sulfur dioxide gas, and the other is the alkali absorption using lye absorption, because the alkali absorption method has high cost and low conversion rate. The reason for the low level is that the domestic bromine factories all adopt the acid absorption method.

The acid method absorption is to use the aqueous solution of sulfur dioxide to react with bromine in the bromine-containing air to form an absorption liquid containing hydrobromic acid. The hydrobromic acid in the absorption liquid reacts with chlorine gas in the distillation tower to generate hydrogen chloride and free bromine. (such as boiler steam) heating, the temperature in the distillation tower reaches above 60 degrees, free bromine turns into bromine vapor and flows out of the distillation tower, and the bromine vapor turns into bromine product after cooling. Sulfur dioxide is produced by burning sulfur, and the heat generated by burning sulfur is not fully applied to the preparation of bromine products, resulting in high energy consumption.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for extracting bromine in brine so as to achieve the purpose of saving energy and reducing consumption.

The method for extracting bromine in brine provided by the present invention is realized by bromine extraction equipment, and its steps include:

(1) Mix the acidified brine and chlorine gas into the oxidation tower to oxidize bromide ions into free bromine to produce oxidized brine; spray the oxidized brine from the top of the blowing tower down to make it blow out of the packing in the tower A liquid film is formed on the surface; at the same time, the fan is blown upward from the bottom of the blowing tower to make the air fully contact with the oxidized brine so that the free bromine is decomposed and diffused into the air to form bromine-containing air, which is blown from the upper part of the blowing tower; bromine-containing air is formed At the same time, sulfur burns in the sulfur combustion furnace to generate high-temperature sulfur dioxide gas, and the sulfur dioxide gas flows through the heat exchange device to cool down and then enters the water washing tower for washing and dust removal;

(2) Mix bromine-containing air, dedusted sulfur dioxide gas and purified sulfur dioxide washing water and send them into the absorption tower. The bromine in the bromine-containing air enters the sulfur dioxide aqueous solution to form an absorption liquid containing hydrobromic acid. The bromine-containing air then It becomes bromine-removing air, and the absorption liquid flows out from the bottom of the absorption tower to the absorption liquid tank, and the bromine-removing air returns to the fan inlet and is sent into the blowing tower by the fan for blowing out bromine;

(3) The absorption liquid in the absorption liquid tank flows through the acid liquid heat exchanger and the heat exchange device to form a liquid above 60°C and enters the distillation tower. The hydrobromic acid in the absorption liquid reacts with the chlorine gas entering the distillation tower to generate hydrogen chloride And free bromine, free bromine is evaporated into bromine vapor under the action of the absorption liquid's own heat, bromine vapor flows out of the distillation tower and becomes the final product bromine after cooling; hydrogen chloride becomes acid liquid when it meets water, and the acid liquid flows out from the bottom of the distillation tower The acid liquid heat exchanger flows through the acid liquid heat exchanger to preheat the absorption liquid flowing into the acid liquid heat exchanger, the acid liquid flowing out of the acid liquid heat exchanger flows through the chlorine gas vaporizer for chlorine gas vaporization, and the acid liquid flowing out of the chlorine gas vaporizer is used for For the acidification of brine; part of the chlorine gas flowing out from the chlorine vaporizer enters the distillation tower for reaction with hydrobromic acid, and the other part is used for the oxidation of acidified brine.

The bromine extraction equipment includes a sulfur combustion furnace, a brine pool, a water washing tower, an absorption tower, a blowing tower, an oxidation tower and a distillation tower; the sulfur combustion furnace is provided with heating tubes, and the heating tubes are connected with a heat exchange device for heat exchange. The air inlet of the device is connected with the smoke outlet of the sulfur combustion furnace, the gas outlet of the heat exchange device is connected with the lower part of the water washing tower, the bottom of the water washing tower is connected with the sedimentation tank, the upper part of the water washing tower is connected with the outlet of the water pump, and the inlet of the water pump is connected with the The sedimentation tank is connected; the brine tank is connected with the water inlet of the oxidation tower through the brine pump and the brine pipe, the water outlet of the oxidation tower is connected with the upper part of the blowing tower, the top of the blowing tower is connected with the top of the absorption tower through the air connecting pipe, and the water washing tower The top and the outlet of the water pump are connected with the air connecting pipe; the bottom of the absorption tower is connected with the absorption liquid tank, the lower part is connected with the inlet of the fan, and the outlet of the fan is connected with the lower part of the blowing tower; the absorption liquid tank is exchanged with the acid liquid through the absorption liquid delivery pump. The absorption liquid inlet of the heat exchanger is connected, the absorption liquid outlet of the acid liquid heat exchanger is connected with the absorption liquid inlet of the heat exchange device, the absorption liquid outlet of the heat exchange device is connected with the upper part of the distillation tower, and the top of the distillation tower is connected with the condenser. The bromine tank is connected with the bromine tank, the bottom of the distillation tower is connected with the acid tank, the acid tank is connected with the acid liquid inlet of the acid liquid heat exchanger through the acid liquid delivery pump, and the acid liquid outlet of the acid liquid heat exchanger is connected with the chlorine vaporizer The acid liquid inlet is connected, the acid liquid outlet of the chlorine gas vaporizer is connected with the brine pipe, the air inlet of the chlorine gas vaporizer is connected with the chlorine gas storage tank, the gas outlet of the chlorine gas vaporizer is connected with the gas inlet of the chlorine buffer tank, and the gas outlet of the chlorine gas buffer tank is connected with the chlorine gas storage tank. The lower part of the distillation tower communicates with the brine pipe.

The heat exchange device includes a primary heat exchanger, a secondary heat exchanger and a tertiary heat exchanger; the air inlet of the primary heat exchanger communicates with the smoke outlet of the sulfur combustion furnace, and the gas outlet communicates with the secondary heat exchange The air inlet of the heat exchanger is connected, the heat transfer oil inlet of the first stage heat exchanger is connected with the outlet of the heating tube, the heat transfer oil outlet is connected with the heat transfer oil inlet of the third stage heat exchanger, and the heat transfer oil outlet of the third stage heat exchanger is connected through the heat conduction The oil pump is connected with the inlet of the heating tube; the gas outlet of the secondary heat exchanger is connected with the lower part of the water washing tower; the absorption liquid inlet of the secondary heat exchanger is connected with the absorption liquid outlet of the acid heat exchanger; The absorption liquid inlet of the heat exchanger is connected, and the absorption liquid outlet of the three-stage heat exchanger is connected with the upper part of the distillation tower.

The heat transfer oil buffer tank is also communicated with the primary heat exchanger.

A foam-catching tower is arranged between the absorption tower and the fan, and the bottom of the foam-catching tower communicates with the lower part of the absorption tower, the top communicates with the inlet of the fan, and the bottom communicates with the absorption liquid tank.

A large amount of additional heat is generated during the sulfur combustion process, and the temperature at the sulfur dioxide outlet of the sulfur combustion furnace can reach above 600 °C. According to the statistics, about 9278kJ of heat is generated by the combustion of sulfur dioxide per kilogram of sulfur, and about 9.278×10 ⁶ kJ of heat per ton of sulfur combustion; at present, about 0.5 tons of sulfur is consumed per ton of bromine production, and the heat released by combustion is about 4.639× 10 ⁶ kJ.

According to the method of the present invention, the absorption liquid containing hydrobromic acid is fully heat-exchanged with the waste heat of the sulfur combustion furnace and high-temperature sulfur dioxide through the heat exchange device, and the temperature of the absorption liquid can reach 80-90 ° C. After the absorption liquid enters the distillation tower, it is mixed with Chlorine gas reacts to generate free bromine, without external heat source heating, free bromine can be converted into bromine vapor from the top port of the distillation tower by relying on the heat of the absorption liquid itself; the whole distillation process does not require external heat source, which can reduce energy consumption. In addition, the acid liquid flowing out from the bottom of the distillation tower also has heat, and the acid liquid heat exchanger can be used to preheat the absorption liquid, and the acid liquid flowing out of the acid liquid heat exchanger also contains heat, which is then used to treat chlorine gas. Vaporize. It can be seen that in the whole production process, the heat required comes from the heat generated by sulfur combustion, and no external heat source is needed, so energy consumption can be greatly reduced.

Description of drawings

The specific embodiment of the present invention is described in further detail below in conjunction with accompanying drawing:

Figure 1 is a schematic diagram of the structure and principle of bromine extraction equipment.

detailed description

The present invention provides a kind of bromine extracting equipment, with reference to Fig. 1, comprise sulfur burning furnace 1, brine pool 2, washing tower 3, absorption tower 4, blowing out tower 5, oxidation tower 6 and distillation tower 7. A heating tube is connected to the inner wall of the sulfur combustion furnace 1 (not shown in the figure, the heating tube can be called a tube heat exchanger, which is a commonly used preheating utilization device for boilers), and the heating tube communicates with the heat exchange device. Described heat exchange device comprises primary heat exchanger 23, secondary heat exchanger 24 and tertiary heat exchanger 25; It is connected with the air inlet of the secondary heat exchanger 24, the heat transfer oil inlet of the primary heat exchanger 23 is connected with the outlet of the heating tube, the heat transfer oil outlet is connected with the heat transfer oil inlet of the third stage heat exchanger 25, and the third stage heat exchanger The heat transfer oil outlet of the heater 25 communicates with the inlet of the heating column tube through a heat transfer oil pump 26 . The gas outlet of the secondary heat exchanger 24 is communicated with the lower part of the water washing tower 3, the absorption liquid inlet of the secondary heat exchanger 24 is communicated with the absorption liquid outlet of the acid liquid heat exchanger 16, and the absorption liquid outlet is connected with the third stage heat exchanger 25. The inlet of the absorption liquid is connected, and the outlet of the absorption liquid of the three-stage heat exchanger 25 is connected with the upper part of the distillation tower 7 . The bottom of water washing tower 3 is communicated with sedimentation tank 8, and the top of water washing tower 3 is communicated with the outlet of water pump 9, and the entrance of water pump 9 is communicated with sedimentation tank 8; Water port is communicated, and the water outlet of oxidation tower 6 is communicated with the top of blowing out tower 5, and the top of blowing out tower 5 is communicated with the top of absorption tower 4 by air connecting pipe 12, and the top of washing tower 3 and the outlet of water pump 9 are connected with air connecting pipe 12 connected; the bottom of the absorption tower 4 communicates with the absorption liquid tank 13, the bottom communicates with the inlet of the blower fan 14, and the outlet of the blower fan 14 communicates with the bottom of the blowing tower 5; The absorption liquid inlet 16 is connected, the top of the distillation tower 7 is connected with the condenser 17, the condenser 17 is connected with the bromine tank 18, and the bottom of the distillation tower 7 is connected with the acid tank 19, and the acid tank 19 is passed through the acid liquid delivery pump 20 It is connected with the acid solution inlet of the acid solution heat exchanger 16, and the acid solution outlet of the acid solution heat exchanger 16 is connected with the acid solution inlet of the chlorine vaporizer 29, and the acid solution outlet brine pipe 11 of the chlorine gas vaporizer 29 is connected, and the acid solution heat exchanger The air inlet of 16 is communicated with the chlorine storage tank 21, the gas outlet of the acid liquid heat exchanger 16 is communicated with the air inlet 22 of the chlorine buffer tank, and the gas outlet of the chlorine buffer tank 22 is communicated with the bottom of the distillation tower 7 and the brine pipe 11 . In order to discharge the acidified brine after blowing bromine, a liquid outlet is provided at the bottom of the blowing tower 5 . The first-stage heat exchanger 23 is also connected with a heat-conducting oil buffer tank 27, and an appropriate amount of heat-conducting oil is added to the heat-conducting oil buffer tank 27 to buffer the heat that flows through the first-stage heat exchanger, the third-stage heat exchanger, and the heating tubes. Volume change of heat transfer oil due to temperature change. In order to prevent the bromine removal air from being mixed with the absorption liquid and enter the fan, a foam trap 28 is arranged between the absorption tower 4 and the fan 14, the bottom of the foam trap 28 communicates with the bottom of the absorption tower 4, the top communicates with the inlet of the fan, The bottom communicates with the absorption liquid tank 13 . The connecting pipelines connecting various components in the bromine extraction equipment can be connected with control valves according to the requirements of use. The use and installation of control valves are conventional technical means and will not be repeated here.

Referring to Fig. 1, the bromine extraction method of the present invention will be described in detail below in conjunction with the above-mentioned bromine extraction equipment. During the initial operation of the equipment, part of the pre-acidified brine is transported to the oxidation tower 6 through the brine pump 10 and the brine pipe 11, and chlorine gas is input into the brine pipe 11 through the chlorine gas storage tank 21, the chlorine gas vaporizer 29, and the chlorine gas buffer tank 22 during the transportation process. , in the brine in the oxidation tower, bromide ions are oxidized to free bromine, thereby producing oxidized brine; under the action of the brine pump 10, the oxidized brine is sprayed downward from the top of the blowing tower 5 to make it on the surface of the packing in the blowing tower Form a liquid film; at the same time, the fan 14 is blown upward from the bottom of the blowing tower 5 to make the air fully contact with the oxidized brine so that the free bromine is decomposed and diffused into the air to form bromine-containing air, which is blown out from the upper part of the blowing tower and enters the air connecting pipe 12 When bromine-containing air is formed, sulfur burns in the sulfur combustion furnace 1 to generate high-temperature sulfur dioxide gas, and the sulfur dioxide gas flows into the primary heat exchanger 23 to exchange heat with the heat-conducting oil for primary cooling, and the cooled sulfur dioxide gas flows into the secondary heat exchange The heat transfer oil in the first-stage heat exchanger enters the third-stage heat exchanger 25 for heat exchange under the action of the heat-conducting oil pump 26, then enters the heating tube, and then enters the first-stage heat exchanger 23. Under the action of the heat-conducting oil pump 26, it flows back and forth in the heating tubes, the first-stage heat exchanger 23 and the third-stage heat exchanger 25, and the process of heat absorption and heat exchange is carried out continuously. The sulfur dioxide gas that has been cooled for the second time flows into the water washing tower 3, and the water pump 9 extracts the water in the sedimentation tank 8 to wash the sulfur dioxide gas to remove unburned sulfur particles or other impurities, and the washing water flows back to the sedimentation tank 8 from the bottom of the water washing tower 3. The sulfur dioxide gas washed by water flows out from the top of the water washing tower 3 and enters the air connecting pipe 12. Meanwhile, the water extracted by the water pump 9 enters the air connecting pipe 12 except that a part is used for washing the sulfur dioxide gas. Sulfur dioxide gas mixes with water in the air connecting pipe 12 to form a sulfur dioxide aqueous solution, and the sulfur dioxide aqueous solution and bromine-containing air enter the top of the absorption tower 4 and flow downward. Under the action of the filler in the absorption tower 4, the sulfur dioxide aqueous solution and the bromine-containing air fully contact, The bromine in the bromine-containing air enters the sulfur dioxide aqueous solution to form an absorption liquid containing hydrobromic acid, and the absorption liquid flows out from the bottom of the absorption tower 4 to the absorption liquid tank 13, and the bromine-containing air becomes bromine-removing air. It flows out from the bottom of the absorption tower 4 and enters the bottom of the foam catcher 28. After removing the absorbing liquid contained in the foam catcher 28, the debrominated air returns to the inlet of the fan 14 through the top of the foam catcher 28 and is sent into the blower tower by the fan for use. Blowing out of bromine. The absorbing liquid at the bottom of the foam collecting tower 28 also enters the absorbing liquid tank 13; the absorbing liquid flow in the absorbing liquid tank 13 flows through the acid liquid heat exchanger 16 for preheating first, and then enters the second stage under the action of the absorbing liquid delivery pump 15. The heat exchange between the primary heat exchanger 24 and the sulfur dioxide gas flowing through the secondary heat exchanger 24 is to heat the absorption liquid once, and the absorption liquid enters the tertiary heat exchanger 25 after flowing out of the secondary heat exchanger 24, and The heat transfer oil flowing through the three-stage heat exchanger 25 performs heat exchange to complete the secondary heating. After the secondary heating, the temperature of the absorption liquid can reach 80-90°C. The absorption liquid flows out of the three-stage heat exchanger 25 and then enters the distillation tower 7. During the downward flow of the absorption liquid from the top of the distillation tower 7, the chlorine gas enters the distillation tower 7 from the bottom of the distillation tower 7, and the absorption liquid and the chlorine gas are fully contacted in the packing in the distillation tower 7, and the hydrobromic acid in the absorption liquid and the Chlorine gas reacts to generate hydrogen chloride and free bromine. Free bromine is evaporated under the action of the absorption liquid’s own heat to form bromine vapor. Bromine vapor flows out from the top of the distillation tower and enters the condenser 17. After cooling, it becomes the final product. Bromine enters bromine Vegetable jar18. When hydrogen chloride meets water, it becomes an acid solution, and the acid solution enters the acid solution tank 19 after flowing out from the bottom of the distillation tower, and under the action of the acid solution delivery pump 20, the acid solution in the acid solution tank 19 enters the acid solution heat exchanger 16 to counterflow the acid solution. The absorption liquid in the liquid heat exchanger is preheated, and the acid solution flowing out from the acid solution heat exchanger 16 flows through the chlorine vaporizer 29 for chlorine vaporization again, and the acid solution flowing out from the chlorine vaporizer 29 flows into the brine pipe 11 for the brine Acidification; the chlorine gas that flows out from the chlorine vaporizer 29 enters the chlorine buffer tank 22, and a part of the chlorine gas that flows out in the chlorine buffer tank 22 enters the distillation tower 7 for reacting with hydrobromic acid in the absorption liquid, and another part flows into the brine pipe 11 for acidification Oxidation of brine.

The above-mentioned bromine extraction process is a continuous production process. Except that the brine needs to be acidified in advance in the initial stage, during normal operation, the brine in the brine pool 2 does not need to be acidified, and directly passes through the brine pump 10 and the brine pipe 11 to The oxidation tower 6 can be transported, and the acid solution in the acid solution tank 19 can enter the brine pipe 11 after passing through the acid solution heat exchanger 16 and the chlorine vaporizer 29 under the action of the acid solution delivery pump 20, and the acid solution is used to acidify the brine, If the degree of acidification is not enough, acid can be suitably replenished in the acid tank 19 during operation. The above bromine extraction process makes full use of the heat generated by sulfur combustion to produce bromine without using external heat sources, which can greatly reduce energy consumption.

Claims (5)

1. a method for extracting bromine in brine, is characterized in that: the method is realized by bromine extraction equipment, and its steps comprise: (1) Mix the acidified brine and chlorine gas into the oxidation tower to oxidize bromide ions into free bromine to produce oxidized brine; spray the oxidized brine from the top of the blowing tower down to make it blow out of the packing in the tower A liquid film is formed on the surface; at the same time, the fan is blown upward from the bottom of the blowing tower to make the air fully contact with the oxidized brine so that the free bromine is decomposed and diffused into the air to form bromine-containing air, which is blown from the upper part of the blowing tower; bromine-containing air is formed At the same time, sulfur burns in the sulfur combustion furnace to generate high-temperature sulfur dioxide gas, and the sulfur dioxide gas flows through the heat exchange device to cool down and then enters the water washing tower for washing and dust removal; (2) Mix bromine-containing air, dedusted sulfur dioxide gas and purified sulfur dioxide washing water and send them into the absorption tower. The bromine in the bromine-containing air enters the sulfur dioxide aqueous solution to form an absorption liquid containing hydrobromic acid. The bromine-containing air then It becomes bromine-removing air, and the absorption liquid flows out from the bottom of the absorption tower to the absorption liquid tank, and the bromine-removing air returns to the fan inlet and is sent into the blowing tower by the fan for blowing out bromine; (3) The absorption liquid in the absorption liquid tank flows through the acid liquid heat exchanger and the heat exchange device to form a liquid above 60°C and enters the distillation tower. The hydrobromic acid in the absorption liquid reacts with the chlorine gas entering the distillation tower to generate hydrogen chloride And free bromine, free bromine is evaporated into bromine vapor under the action of the heat of the absorption liquid itself, and the bromine vapor flows out of the distillation tower and becomes the final product bromine after cooling; hydrogen chloride becomes acid liquid when it meets water, and the acid liquid flows out from the distillation tower The acid liquid heat exchanger flows through the acid liquid heat exchanger to preheat the absorption liquid flowing into the acid liquid heat exchanger, the acid liquid flowing out of the acid liquid heat exchanger flows through the chlorine gas vaporizer for chlorine gas vaporization, and the acid liquid flowing out of the chlorine gas vaporizer is used for For the acidification of brine; part of the chlorine gas flowing out from the chlorine vaporizer enters the distillation tower for reaction with hydrobromic acid, and the other part is used for the oxidation of acidified brine. 2. The method for extracting bromine in brine as claimed in claim 1, characterized in that: the bromine extraction equipment comprises a sulfur combustion furnace (1), a brine pool (2), a washing tower (3), an absorption tower ( 4), the blowing tower (5), the oxidation tower (6) and the distillation tower (7); the sulfur combustion furnace (1) is equipped with heating tubes, and the heating tubes are connected with the heat exchange device, and the air inlet of the heat exchange device It is connected with the smoke outlet of the sulfur combustion furnace (1), the gas outlet of the heat exchange device is connected with the lower part of the water washing tower (3), the bottom of the water washing tower (3) is connected with the sedimentation tank (8), and the upper part of the water washing tower (3) It is connected with the outlet of the water pump (9), and the inlet of the water pump (9) is connected with the sedimentation tank (8); the brine tank (2) is connected with the water inlet of the oxidation tower (6) through the brine pump (10) and the brine pipe (11) , the water outlet of the oxidation tower (6) communicates with the upper part of the blowing tower (5), the top of the blowing tower (5) communicates with the top of the absorption tower (4) through the air connecting pipe (12), and the top of the water washing tower (3) And the outlet of the water pump (9) is connected with the air connecting pipe (12); the bottom of the absorption tower (4) is connected with the absorption liquid tank (13), the lower part is connected with the inlet of the fan (14), and the outlet of the fan (14) is connected with the blown out The lower part of the tower (5) is connected; the absorption liquid tank (13) is connected with the absorption liquid inlet of the acid liquid heat exchanger (16) through the absorption liquid delivery pump (15), and the absorption liquid outlet of the acid liquid heat exchanger (16) is connected with the The absorption liquid inlet of the heat exchange device is connected, the absorption liquid outlet of the heat exchange device is connected with the upper part of the distillation tower (7), the top of the distillation tower (7) is connected with the condenser (17), and the condenser (17) is connected with the bromine tank ( 18) is connected, the bottom of the distillation tower (7) is connected with the acid liquid tank (19), and the acid liquid tank (19) is connected with the acid liquid inlet of the acid liquid heat exchanger (16) through the acid liquid delivery pump (20), and the acid liquid The acid liquid outlet of the liquid heat exchanger (16) is connected with the acid liquid inlet of the chlorine gas vaporizer, the acid liquid outlet of the chlorine gas vaporizer is connected with the brine pipe (11), the air inlet of the chlorine gas vaporizer is connected with the chlorine gas storage tank (21), and the chlorine gas The gas outlet of the vaporizer communicates with the inlet of the chlorine buffer tank (22), and the gas outlet of the chlorine buffer tank (22) communicates with the lower part of the distillation tower (7) and the brine pipe (11). 3. The method for extracting bromine in brine as claimed in claim 2, characterized in that: the heat exchange device includes a primary heat exchanger (23), a secondary heat exchanger (24) and a tertiary heat exchanger (25); the air inlet of the primary heat exchanger (23) communicates with the smoke outlet of the sulfur combustion furnace (1), and the gas outlet communicates with the air inlet of the secondary heat exchanger (24), and the primary heat exchange The heat transfer oil inlet of the device (23) is connected with the outlet of the heating tube, the heat transfer oil outlet is connected with the heat transfer oil inlet of the third-stage heat exchanger (25), and the heat transfer oil outlet of the third-stage heat exchanger (25) passes through the heat transfer oil pump ( 26) It is connected with the inlet of the heating tube; the gas outlet of the secondary heat exchanger (24) is connected with the lower part of the water washing tower (3), and the absorption liquid inlet of the secondary heat exchanger (24) is connected with the acid liquid heat exchanger (16) ) is connected to the absorption liquid outlet, the absorption liquid outlet is connected to the absorption liquid inlet of the three-stage heat exchanger (25), and the absorption liquid outlet of the three-stage heat exchanger (25) is connected to the upper part of the distillation tower (7). 4 . The method for extracting bromine in brine according to claim 2 , characterized in that: the primary heat exchanger ( 23 ) is also connected with a heat transfer oil buffer tank ( 27 ). 5. The method for extracting bromine in brine according to any one of claims 2-4, characterized in that: a foam trap (28) is set between the absorption tower (4) and the fan (14) , the lower part of the foam collecting tower (28) communicates with the lower part of the absorption tower (4), the top communicates with the inlet of the fan, and the bottom communicates with the absorption liquid tank (13).

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