Bromine distillation apparatus

Abstract

The application relates to a bromine distillation device, which relates to the technical field of bromine distillation and comprises a distillation tower, a reboiler connected with a raw material inlet of the distillation tower, top heat exchange plates, middle heat exchange plates and bottom heat exchange plates arranged in parallel from top to bottom in the distillation tower, a steam outlet at the top of the distillation tower connected with a steam waste heat recovery module, a steam outlet of the steam waste heat recovery module connected with the top heat exchange plates, the middle heat exchange plates and the reboiler, and the reboiler connected with a raw material supply pipeline. The application is used to solve the problems in the prior art, such as that the bromine distillation relies on the centralized heating of the tower bottom reboiler, the temperature difference in the tower is large, bromine steam is prone to backflow, the separation effect is poor, the energy consumption is high, the heat source regulation in the tower is poor, the waste heat is not utilized in stages, the waste is serious, the temperature level matching of the waste heat system is unreasonable, reverse heat transfer is prone to occur, the working condition stability is poor, the process condensate water is directly discharged, water and waste heat are wasted, and the economy and environmental protection of the device are poor.

Description

Technical Field

[0001] This invention relates to the field of bromine distillation technology, and more specifically to bromine distillation apparatus. Background Technology

[0002] Bromine is an important basic chemical raw material, widely used in flame retardants, pharmaceuticals, pesticides, oilfield chemicals, water treatment, and many other fields. In industrial production, regardless of whether seawater, brine, or mineral bromine extraction processes are used, distillation is the core process for bromine separation, purification, and refining, directly determining the purity, yield, and energy consumption of the bromine product. The crude bromine solution obtained after previous oxidation, blowing, and absorption processes has a complex composition, containing water, salts, organic acids, and other impurities, and cannot be used directly as a finished product. Distillation is essential for the efficient separation of bromine from these impurities. Bromine distillation utilizes the differences in boiling point and volatility between bromine and associated components, employing the mass and heat transfer principles of heating and vaporization, gas-phase ascent, and condensation and liquefaction to continuously separate gaseous bromine from the mixture, ultimately yielding a high-purity liquid bromine product.

[0003] Currently, the mainstream bromine distillation units in industry mainly use atmospheric / vacuum distillation towers as the main equipment, and generally adopt the centralized heating mode of reboiler at the bottom of the tower: the reboiler heats the material in the bottom of the tower to generate rising gas phase, which flows from bottom to top along the tower body and comes into countercurrent contact with the falling liquid phase to complete mass transfer. High-concentration bromine vapor is drawn out from the top of the tower and condensed and collected, while high-salt waste liquid is continuously discharged from the bottom of the tower.

[0004] A prior art patent, CN105668520A, describes a bromine distillation column with a tetrafluoroethylene lining. The column comprises, from bottom to top, a heat exchange layer, a blow-out layer, a reaction layer, and a distillation layer. The heat exchange layer has a primary feed inlet and outlet on its sidewall, and a waste liquid outlet at its bottom. The blow-out layer has a steam inlet and a chlorine inlet on its sidewall. The reaction layer has a heating feed inlet and a reflux inlet at its upper part, connected to the primary feed outlet. The distillation layer has a bromine vapor outlet at its top, connected to a cooling device. This cooling device is connected to a bromine-water separation device, which has a bromine elemental outlet and a reflux outlet, connected to the reflux inlet. This design allows for a larger distillation volume, further improving the quality and yield of bromine.

[0005] Existing devices, including those mentioned above, have gradually revealed shortcomings with use, mainly in the following aspects: First, traditional processes rely solely on centralized heating from the reboiler at the bottom of the tower. The temperature drop during the upward movement of the gas phase is significant, and the excessive longitudinal temperature difference within the tower easily causes bromine vapor to condense and reflux, directly reducing material separation efficiency, product purity, and bromine recovery rate. At the same time, it forces the reboiler to operate under overload for extended periods, resulting in high system steam energy consumption and overall operating costs.

[0006] Secondly, the original heat exchange medium was arranged in series, and the heat sources in each zone interfered with each other, making it impossible to achieve independent control of each zone. It lacked a layered temperature control and flow regulation structure, making it difficult to dynamically adapt to changes in production conditions, and the temperature field inside the tower was unstable. Various types of waste heat in the device were only simply recovered and could not be distributed and utilized in stages according to the temperature level of the medium. Different grades of waste heat were mismatched and used, the heat energy flow direction was chaotic, a large amount of waste heat was wasted, and the overall energy utilization rate was low.

[0007] Third, existing waste heat solutions have defects such as improper medium access location and temperature mismatch, which easily lead to reverse heat transfer phenomenon where the temperature of the heat medium is lower than the temperature of the liquid to be heated. This not only fails to achieve effective waste heat but also causes heat loss. The multi-stage heat exchange loops are cross-coupled, and fluctuations in the operating conditions of a single component will affect the overall waste heat effect, resulting in poor stability of raw material waste heat.

[0008] Fourth, in traditional processes, the condensate generated by heat pumps and reboilers is directly discharged, which not only causes the loss of clean water resources, but also wastes the medium and low temperature residual heat carried in the condensate. The reboiler continuously replenishes ambient temperature feedwater, further increasing the consumption of external steam. The equipment has high water and energy consumption, and is not environmentally friendly or economical.

[0009] In conclusion, the existing technology obviously has inconveniences and defects in practical use, so it is necessary to improve it. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides a bromine distillation apparatus to solve the problems of traditional bromine distillation, which relies on centralized heating from a reboiler at the bottom of the column, resulting in large temperature differences within the column, easy reflux of bromine vapor, poor separation effect, and high energy consumption; poor heat source control within the column, leading to serious waste due to lack of cascade utilization of waste heat; unreasonable temperature matching in the waste heat system, which easily causes reverse heat transfer and poor operating stability; and direct discharge of process condensate, resulting in double waste of water and waste heat, and poor economic and environmental performance of the apparatus.

[0011] To address the above problems, the present invention provides the following technical solution: A bromine distillation apparatus includes a distillation column, the feed inlet of which is connected to a reboiler. The distillation column contains a top heat exchange plate, a middle heat exchange plate, and a bottom heat exchange plate arranged in parallel from top to bottom. A steam waste heat recovery module is connected to the steam outlet at the top of the distillation column. The steam outlet of the steam waste heat recovery module is connected to the top heat exchange plate, the middle heat exchange plate, and the reboiler. The reboiler is connected to the feed supply pipeline. The condensate outlets of the top heat exchange plate, the middle heat exchange plate, and the bottom heat exchange plate are connected to the raw material supply pipeline through the condensate waste heat recovery module. The waste liquid outlet of the distillation column and the condensate outlet of the reboiler are connected to a gradient waste heat recovery module. The gradient waste heat recovery module and the condensate waste heat recovery module are sequentially connected to the raw material supply pipeline along the raw material inlet direction.

[0012] As an optimized solution, the gradient waste heat recovery module includes a waste liquid waste heat recovery unit and a reboiler condensate waste heat recovery unit. The cold side inlet of the waste liquid waste heat recovery unit is connected to the raw material inlet pipeline, and the cold side outlet of the waste liquid waste heat recovery unit is connected to the cold side inlet of the reboiler condensate waste heat recovery unit.

[0013] As an optimized solution, the condensate waste heat recovery module includes a condensate waste heat recovery unit, and the cold-side outlet of the reboiler condensate waste heat recovery unit is connected to the cold-side inlet of the condensate waste heat recovery unit.

[0014] As an optimized solution, the steam waste heat recovery module includes a heat pump. The steam inlet of the heat pump is connected to the steam outlet at the top of the distillation column. The steam outlet of the heat pump is connected to the top heat exchange plate, the middle heat exchange plate, and the reboiler via parallel top steam pipeline, middle steam pipeline, and raw material heating pipeline.

[0015] As an optimized solution, the cold-side outlet of the condensate waste heat recovery unit is also connected to the bottom heat exchange plate via a bottom steam pipeline.

[0016] As an optimized solution, regulating valves are connected to the top steam pipeline, the middle steam pipeline and the bottom steam pipeline respectively, and the opening degree of the three regulating valves is set in a decreasing manner from top to bottom.

[0017] As an optimized solution, the condensate outlet of the reboiler is connected to the hot-side inlet of the reboiler condensate waste heat recovery unit via the reboiler condensate inlet pipeline.

[0018] As an optimized solution, the hot-side inlet of the waste liquid heat recovery unit is connected to the waste liquid outlet of the distillation column.

[0019] As an optimized solution, the hot-side inlet of the condensate waste heat recovery unit is connected to the condensate outlets of the top heat exchange plate, the middle heat exchange plate, and the bottom heat exchange plate via a condensate recovery pipeline.

[0020] As an optimized solution, the hot-side outlet of the reboiler condensate waste heat recovery unit is connected to the hot-side inlet of the condensate waste heat recovery unit via the reboiler condensate discharge pipeline.

[0021] As an optimized solution, a waste liquid waste heat secondary utilization pipeline is connected between the hot side outlet of the condensate waste heat recovery unit and the hot side outlet of the waste liquid waste heat recovery unit. The waste liquid waste heat secondary utilization pipeline is connected to a tail heat exchanger. The cold side outlet of the tail heat exchanger is connected to the inlet end of the reboiler through a water supply pipeline.

[0022] As an optimized solution, the cold-side inlet of the tail heat exchanger is connected to the hot-side outlet of the condensate waste heat recovery unit, and the hot-side inlet of the tail heat exchanger is connected to the hot-side outlet of the waste liquid waste heat recovery unit.

[0023] As an optimized solution, the raw material supply pipeline includes pipelines connected to the waste liquid waste heat recovery unit, the reboiler condensate waste heat recovery unit, and the cold side inlet and cold side outlet of the condensate waste heat recovery unit.

[0024] As an optimized solution, the hot-side outlet of the tail heat exchanger is connected to an external drain.

[0025] As an optimized solution, the heat pump is an MVR heat pump.

[0026] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes a heat pump to compress and upgrade the secondary steam at the top of a distillation column, distributing the high-temperature steam to the top, middle heat exchange plates, and reboiler within the column. This achieves layered, distributed heat replenishment within the column, changing the traditional centralized heating mode of a single reboiler. It effectively offsets heat loss during the upward flow of the gas phase, significantly reduces the longitudinal temperature difference within the column, fundamentally prevents bromine vapor condensation and reflux, enhances gas-liquid mass transfer, and significantly improves bromine separation efficiency, product purity, and material recovery rate. Simultaneously, it alleviates the heating pressure on the reboiler, freeing it from long-term overload operation, effectively reducing equipment wear and overall steam consumption, and lowering production and operating costs. To address the issue of high temperatures at the bottom of the tower, the bottom heat exchange plate introduces high-temperature raw materials heated by the condensate waste heat recovery unit as a heat source. This effectively avoids the problem of temperature inversion and reverse heat exchange caused by low-temperature steam entering the high-temperature area, and prevents the temperature field at the bottom of the tower from being disturbed. The heat source temperature level is precisely matched with the operating conditions at the bottom of the tower. While achieving stable auxiliary heat exchange, it also utilizes the heat carried by the raw materials again to further improve the thermal energy utilization rate and ensure the stable operation of heat and mass transfer at the bottom of the tower. By sequentially installing regulating valves with decreasing openings on the top, middle, and bottom steam pipelines, the temperature in different areas of the tower decreases from bottom to top due to the reboiler being located at the bottom. This allows for temperature difference compensation by utilizing the valve openings of the heat exchange plates at the top, middle, and bottom. It also enables zoned differentiated heat distribution, dynamically adapting to changes in operating conditions such as feed concentration and throughput, resulting in a more uniform and stable overall temperature field distribution within the tower. Reboiler condensate is a medium-temperature waste heat medium. Through this pipeline layout, after completing the secondary preheating of the raw materials, it continues to enter the condensate waste heat recovery unit to participate in the tertiary heat exchange, continuously releasing residual heat. This achieves the stepwise utilization of high and medium-temperature waste heat, avoiding the heat energy waste caused by the one-time discharge of reboiler condensate waste heat, maximizing the value of condensate waste heat, significantly improving the overall heat energy recovery rate of the system, and ensuring that the temperature level of each stage of waste heat utilization is reasonably matched, with no heat mismatch and no energy waste. This invention arranges waste liquid heat recovery units, reboiler condensate heat recovery units, and condensate heat recovery units sequentially along the raw material conveying direction, constructing a complete tiered waste heat utilization chain according to the medium temperature. High-grade heat is preferentially used for the initial preheating of raw materials, while medium and low-temperature tail heat is recovered secondary and tertiary, completely solving the problems of simple waste heat recovery and mismatched use of high and low grade heat energy in traditional processes. The system fully recovers various waste heat resources such as high-temperature waste liquid at the bottom of the tower, reboiler condensate, and condensate from the heat exchange plates inside the tower, minimizing heat loss and significantly improving the comprehensive energy utilization rate. This invention features a specific design for the medium inlet location and flow path of each heat exchange module. The raw material cold flow and various heat media are arranged strictly according to the forward heat exchange logic. The temperature of the heat media is always higher than the temperature of the heated liquid, which completely avoids the reverse heat transfer problem caused by temperature mismatch in traditional preheating systems, avoids ineffective heat loss, and ensures that each preheating unit can stably perform its heat exchange function. The clean condensate generated by the heat exchange plates and reboiler in the tower is no longer directly discharged, but is all collected into the condensate waste heat recovery module to participate in heat exchange. The low-temperature condensate after heat exchange enters the tail heat exchanger, and after recovering the tail heat of the waste liquid to complete the temperature increase, it is transported to the reboiler as makeup water, forming a closed-loop recycling of condensate throughout the entire process. On the one hand, it completely solves the problem of water waste caused by direct discharge of process condensate and reduces wastewater discharge. On the other hand, it uses the waste heat of the waste liquid after the initial heat exchange to preheat the reboiler makeup water, replacing the traditional ambient temperature feed water, further reducing the heating load of the reboiler and the consumption of external steam. The whole set of equipment achieves dual optimization in water resources and energy utilization, and the overall economic and environmental performance is greatly improved. This invention integrates functions such as steam upgrading and heating, stratified heating in the tower, gradient preheating of raw materials, condensate recycling, and secondary utilization of tail heat into one unit. Each module operates in coordination and is logically self-consistent. The overall structure is reasonably laid out and can be adapted to the high salt content and highly corrosive bromine distillation conditions. It has high operational reliability, effectively extends the continuous operation cycle of the unit, and reduces the later maintenance and operation costs, thus possessing good value for promotion and application. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0028] Figure 1 This is a schematic diagram of the structure of the present invention.

[0029] In the diagram: 1-Distillation column; 2-Top heat exchange plate; 3-Middle heat exchange plate; 4-Bottom heat exchange plate; 5-Waste liquid waste heat recovery unit; 6-Reboiler condensate waste heat recovery unit; 7-Reboiler; 8-Heat pump; 9-Condensate recovery pipeline; 10-Condensate waste heat recovery unit; 11-Raw material inlet pipeline; 12-Tail heat exchanger; 13-Top steam pipeline; 14-Middle steam pipeline; 15-Bottom steam pipeline; 16-Regulating valve; 17-Waste liquid waste heat secondary utilization pipeline; 18-Make-up water pipeline; 19-Reboiler condensate inlet pipeline; 20-Reboiler condensate outlet pipeline; 21-Raw material heating pipeline. Detailed Implementation

[0030] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0031] like Figure 1 As shown, the bromine distillation apparatus includes a distillation column 1. The feed inlet of the distillation column 1 is connected to a reboiler 7. The distillation column 1 is provided with a top heat exchange plate 2, a middle heat exchange plate 3, and a bottom heat exchange plate 4 arranged in parallel from top to bottom. The steam outlet at the top of the distillation column 1 is connected to a steam waste heat recovery module. The steam outlet of the steam waste heat recovery module is connected to the top heat exchange plate 2, the middle heat exchange plate 3, and the reboiler 7. The reboiler 7 is connected to the feed supply pipeline. The condensate outlets of the top heat exchange plate 2, the middle heat exchange plate 3, and the bottom heat exchange plate 4 are connected to the raw material supply pipeline through the condensate waste heat recovery module. The waste liquid outlet of distillation column 1 and the condensate outlet of reboiler 7 are connected to a gradient waste heat recovery module. The gradient waste heat recovery module and the condensate waste heat recovery module are connected sequentially to the raw material supply pipeline along the raw material inlet direction.

[0032] The gradient waste heat recovery module includes a waste liquid waste heat recovery unit 5 and a reboiler condensate waste heat recovery unit 6. The cold side inlet of the waste liquid waste heat recovery unit 5 is connected to the raw material inlet pipeline 11, and the cold side outlet of the waste liquid waste heat recovery unit 5 is connected to the cold side inlet of the reboiler condensate waste heat recovery unit 6.

[0033] The condensate waste heat recovery module includes a condensate waste heat recovery unit 10, and the cold side outlet of the reboiler condensate waste heat recovery unit 6 is connected to the cold side inlet of the condensate waste heat recovery unit 10.

[0034] The steam waste heat recovery module includes a heat pump 8. The steam inlet end of the heat pump 8 is connected to the steam outlet at the top of the distillation column 1. The steam outlet end of the heat pump 8 is connected to the top heat exchange plate 2, the middle heat exchange plate 3 and the reboiler 7 respectively through the top steam pipeline 13, the middle steam pipeline 14 and the raw material heating pipeline 21 arranged in parallel.

[0035] The cold side outlet of the condensate waste heat recovery unit 10 is also connected to the bottom heat exchange plate 4 via the bottom steam line 15.

[0036] A regulating valve 16 is connected to the top steam pipeline 13, the middle steam pipeline 14 and the bottom steam pipeline 15 respectively, and the opening of the three regulating valves 16 is set in a decreasing manner from top to bottom.

[0037] The condensate outlet of reboiler 7 is connected to the hot side inlet of reboiler condensate waste heat recovery unit 6 via reboiler condensate inlet pipeline 19.

[0038] The hot-side inlet of the waste liquid heat recovery unit 5 is connected to the waste liquid outlet of the distillation column 1.

[0039] The hot side inlet of the condensate waste heat recovery unit 10 is connected to the condensate outlet of the top heat exchange plate 2, the middle heat exchange plate 3, and the bottom heat exchange plate 4 via the condensate recovery pipeline 9.

[0040] The hot side outlet of the reboiler condensate waste heat recovery unit 6 is connected to the hot side inlet of the condensate waste heat recovery unit 10 via the reboiler condensate discharge pipeline 20.

[0041] A waste liquid waste heat recovery pipeline 17 is connected between the hot side outlet of the condensate waste heat recovery unit 10 and the hot side outlet of the waste liquid waste heat recovery unit 5. The waste liquid waste heat recovery pipeline 17 is connected to the tail heat exchanger 12. The cold side outlet of the tail heat exchanger 12 is connected to the inlet end of the reboiler 7 through the water supply pipeline 18.

[0042] The cold side inlet of the tail heat exchanger 12 is connected to the hot side outlet of the condensate waste heat recovery unit 10, and the hot side inlet of the tail heat exchanger 12 is connected to the hot side outlet of the waste liquid waste heat recovery unit 5.

[0043] The raw material supply pipelines include pipelines connecting the cold side inlet and cold side outlet of the waste liquid waste heat recovery unit 5, the reboiler condensate waste heat recovery unit 6, and the condensate waste heat recovery unit 10.

[0044] The hot side outlet of the tail heat exchanger 12 is connected to the external exhaust.

[0045] Heat pump 8 is an MVR heat pump 8.

[0046] In the process flow of this device, the overall temperature change is as follows: The raw material has an initial temperature of 25–35°C and flows sequentially through the waste liquid heat recovery unit 5, the reboiler condensate heat recovery unit 10, and the condensate heat recovery unit 10 to complete three-stage preheating, with the temperature gradually increasing to 75–85°C, 82–90°C, and finally reaching 88–93°C. A portion of the high-temperature raw material is diverted to the bottom heat exchange plate 4 as a heat source, while the remainder is sent to the reboiler and distillation column 1. The waste liquid discharged from distillation column 1 has an initial temperature of 105–115°C. After releasing heat in the waste liquid heat recovery unit 5, it cools to 75–85°C, then enters the tail heat exchanger 12 to release remaining heat, finally cooling to 50–60°C before being discharged. The condensate produced by the reboiler at 90-100℃ first enters the reboiler condensate waste heat recovery unit 10 to release heat. After the temperature drops to 82-90℃, it is sent to the hot side of the condensate waste heat recovery unit 10. The secondary steam at 78-85℃ from the top of the distillation column 1 is compressed and upgraded to 85-98℃ by the MVR heat pump 8, and then sent to the top and middle heat exchange plates 3 and the reboiler for heating. After heat exchange, condensate at 80-90℃ is generated, which also flows into the hot side of the condensate waste heat recovery unit 10. The two streams of condensate release heat simultaneously here, and the temperature drops to 65-75℃. Then they enter the tail heat exchanger 12 together to absorb the tail heat of the waste liquid and raise the temperature to 70-80℃. Finally, it is returned to the reboiler as makeup water to complete the cycle.

[0047] The working principle of this device is as follows: This invention utilizes a heat pump 8 to compress and upgrade the secondary steam at the top of the distillation column 1, distributing the high-temperature steam to the top and middle heat exchange plates 3 and the reboiler within the column. This achieves layered, distributed heat replenishment within the column, changing the traditional centralized heating mode of a single reboiler. It effectively offsets heat loss during the upward flow of the gas phase, significantly reduces the longitudinal temperature difference within the column, fundamentally prevents bromine vapor condensation and reflux, enhances gas-liquid mass transfer, and significantly improves bromine separation efficiency, product purity, and material recovery rate. Simultaneously, it alleviates the heating pressure on the reboiler, freeing it from long-term overload operation, effectively reducing equipment wear and overall steam consumption, and lowering production and operating costs. In response to the high temperature at the bottom of the tower, the bottom heat exchange plate 4 introduces the high-temperature raw material heated by the condensate waste heat recovery unit 10 as a heat source. This effectively avoids the problem of temperature difference inversion and reverse heat exchange caused by low-temperature steam entering the high-temperature area, and prevents the temperature field at the bottom of the tower from being disturbed. The temperature level of the heat source is precisely matched with the operating conditions at the bottom of the tower. While achieving stable auxiliary heat exchange, the heat carried by the raw material is reused to further improve the thermal energy utilization rate and ensure the stable operation of heat transfer and mass transfer at the bottom of the tower. A series of regulating valves 16 with decreasing opening degrees are installed on the top, middle, and bottom steam pipelines 15. Since the reboiler 7 is located at the bottom of the tower, the temperature in different areas decreases from bottom to top. The valve openings of the top, middle, and bottom heat exchange plates 4 are used to compensate for the temperature difference. This enables zoned differentiated heat distribution and can dynamically adapt to changes in operating conditions such as feed concentration and throughput, making the overall temperature field distribution in the tower more uniform and stable. The reboiler condensate is a medium-temperature waste heat medium. Through this pipeline layout, after completing the secondary preheating of the raw materials, it continues to enter the condensate waste heat recovery unit 10 to participate in the tertiary heat exchange, continuously releasing residual heat. This achieves the stepwise utilization of high and medium-temperature waste heat, avoiding the heat energy waste caused by the one-time discharge of reboiler condensate waste heat, maximizing the value of condensate waste heat, significantly improving the overall heat energy recovery rate of the system, and ensuring that the temperature level of each stage of waste heat utilization is reasonably matched, with no heat mismatch and no energy waste. This invention arranges a waste liquid heat recovery unit 5, a reboiler condensate heat recovery unit 10, and a condensate heat recovery unit 10 sequentially along the raw material conveying direction. A complete tiered waste heat utilization chain is built according to the medium temperature, prioritizing the use of high-grade heat for initial raw material preheating, while medium- and low-temperature tail heat is recovered secondary and tertiary. This completely solves the problems of simple waste heat recovery and mismatched use of high and low-grade heat energy in traditional processes. The system fully recovers various waste heat resources such as high-temperature waste liquid at the bottom of the tower, reboiler condensate, and condensate from the heat exchange plates inside the tower, minimizing heat loss and significantly improving the overall energy utilization rate. This invention features a specific design for the medium inlet location and flow path of each heat exchange module. The raw material cold flow and various heat media are arranged strictly according to the forward heat exchange logic. The temperature of the heat media is always higher than the temperature of the heated liquid, which completely avoids the reverse heat transfer problem caused by temperature mismatch in traditional preheating systems, avoids ineffective heat loss, and ensures that each preheating unit can stably perform its heat exchange function. The clean condensate generated by the heat exchange plates and reboiler in the tower is no longer directly discharged, but is all collected into the condensate waste heat recovery module to participate in heat exchange. The low-temperature condensate after heat exchange enters the tail heat exchanger 12. After recovering the tail heat of the waste liquid to complete the temperature increase, it is transported to the reboiler as makeup water, forming a closed-loop recycling of condensate throughout the entire process. On the one hand, it completely solves the problem of water waste caused by direct discharge of process condensate and reduces wastewater discharge. On the other hand, it uses the waste heat of the waste liquid after the initial heat exchange to preheat the reboiler makeup water, replacing the traditional ambient temperature feed water, further reducing the heating load of the reboiler and the consumption of external steam. The whole set of equipment achieves dual optimization in water resources and energy utilization, and the overall economic and environmental performance is greatly improved. This invention integrates functions such as steam upgrading and heating, stratified heating in the tower, gradient preheating of raw materials, condensate recycling, and secondary utilization of tail heat into one unit. Each module operates in coordination and is logically self-consistent. The overall structure is reasonably laid out and can be adapted to the high salt content and highly corrosive bromine distillation conditions. It has high operational reliability, effectively extends the continuous operation cycle of the unit, and reduces the later maintenance and operation costs, thus possessing good value for promotion and application.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A bromine distillation apparatus, characterized in that: The distillation column (1) is connected to a reboiler (7) at its feed inlet. The distillation column (1) is provided with a top heat exchange plate (2), a middle heat exchange plate (3), and a bottom heat exchange plate (4) arranged in parallel from top to bottom. The steam outlet at the top of the distillation column (1) is connected to a steam waste heat recovery module. The steam outlet of the steam waste heat recovery module is connected to the top heat exchange plate (2), the middle heat exchange plate (3), and the reboiler (7). The reboiler (7) is connected to the feed supply pipeline. The condensate outlets of the top heat exchange plate (2), the middle heat exchange plate (3) and the bottom heat exchange plate (4) are connected to the raw material supply pipeline through the condensate waste heat recovery module. The waste liquid outlet of the distillation tower (1) and the condensate outlet of the reboiler (7) are connected to a gradient waste heat recovery module. The gradient waste heat recovery module and the condensate waste heat recovery module are sequentially connected to the raw material supply pipeline along the raw material inlet direction.

2. The bromine distillation apparatus according to claim 1, characterized in that: The gradient waste heat recovery module includes a waste liquid waste heat recovery unit (5) and a reboiler condensate waste heat recovery unit (6). The cold side inlet of the waste liquid waste heat recovery unit (5) is connected to the raw material inlet pipeline (11), and the cold side outlet of the waste liquid waste heat recovery unit (5) is connected to the cold side inlet of the reboiler condensate waste heat recovery unit (6).

3. The bromine distillation apparatus according to claim 1, characterized in that: The condensate waste heat recovery module includes a condensate waste heat recovery unit (10), and the cold side outlet of the reboiler condensate waste heat recovery unit (6) is connected to the cold side inlet of the condensate waste heat recovery unit (10).

4. The bromine distillation apparatus according to claim 1, characterized in that: The steam waste heat recovery module includes a heat pump (8). The steam inlet end of the heat pump (8) is connected to the steam outlet at the top of the distillation column (1). The steam outlet end of the heat pump (8) is connected to the top heat exchange plate (2), the middle heat exchange plate (3) and the reboiler (7) through the top steam pipeline (13), the middle steam pipeline (14) and the raw material heating pipeline (21) arranged in parallel.

5. The bromine distillation apparatus according to claim 1, characterized in that: The cold side outlet of the condensate waste heat recovery unit (10) is also connected to the bottom heat exchange plate (4) via a bottom steam line (15).

6. The bromine distillation apparatus according to claim 1, characterized in that: The condensate outlet of the reboiler (7) is connected to the hot side inlet of the reboiler condensate waste heat recovery unit (6) via the reboiler condensate inlet pipeline (19).

7. The bromine distillation apparatus according to claim 1, characterized in that: The hot side inlet of the condensate waste heat recovery unit (10) is connected to the condensate outlet of the top heat exchange plate (2), the middle heat exchange plate (3) and the bottom heat exchange plate (4) through the condensate recovery pipeline (9).

8. The bromine distillation apparatus according to claim 1, characterized in that: The hot-side outlet of the reboiler condensate waste heat recovery unit (6) is connected to the hot-side inlet of the condensate waste heat recovery unit (10) via the reboiler condensate discharge pipeline (20).

9. The bromine distillation apparatus according to claim 1, characterized in that: A waste liquid waste heat recovery pipeline (17) is connected between the hot side outlet of the condensate waste heat recovery unit (10) and the hot side outlet of the waste liquid waste heat recovery unit (5). The waste liquid waste heat recovery pipeline (17) is connected to a tail heat exchanger (12). The cold side outlet of the tail heat exchanger (12) is connected to the inlet end of the reboiler (7) through a water supply pipeline (18).

10. The bromine distillation apparatus according to claim 1, characterized in that: The cold-side inlet of the tail heat exchanger (12) is connected to the hot-side outlet of the condensate waste heat recovery unit (10), and the hot-side inlet of the tail heat exchanger (12) is connected to the hot-side outlet of the waste liquid waste heat recovery unit (5).

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