System and method capable of continuously producing hydrogen iodide solution

Abstract

The invention discloses a system and a method capable of continuously producing a hydrogen iodide solution. The system comprises a separation tank, an absorption tower, a circulating pump and the like, the method comprises the following steps: introducing flue gas in a flue behind an induced draft fan into a washing device, enabling the washed flue gas to enter an absorption tower, enabling sulfur dioxide in the flue gas to react with an iodine solution from a circulating pump, and consuming the sulfur dioxide to generate a hydrogen iodide solution and a sulfuric acid solution; the flue gas with sulfur dioxide removed from the absorption tower enters an iodine blocking device, and the flue gas after the solution in the iodine blocking tower absorbs iodine escaping from the absorption tower enters a flue gas emission device; the solution entering the distillation section passes through the rectifying section and the stripping section to obtain a pure high-concentration hydrogen iodide solution, and the hydrogen iodide solution is partially decomposed in a hydrogen iodide decomposition device to generate hydrogen; and after part of hydrogen iodide is extracted from the mixed liquid discharged into the distillation section from the separation device, the residual liquid enters the tower kettle and is discharged into the separation tank by a tower kettle discharge pump.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive utilization of boiler flue gas and hydrogen production, and particularly relates to a system and method for continuously producing hydrogen iodide solution. Background Art

[0002] The sulfur-iodine cycle for hydrogen production is a thermochemical hydrogen production method, which has the advantage of high thermal efficiency compared with electrolytic water hydrogen production. However, sulfur dioxide in the sulfur-iodine cycle process needs to be catalytically decomposed from sulfuric acid at a high temperature above 800 °C.

[0003] Using iodine to absorb sulfur dioxide in flue gas to obtain hydrogen iodide for hydrogen production realizes waste utilization, environmental protection and the preparation of green hydrogen, and has good social and economic benefits. However, the following problems exist in this method at present: (1) The products of the Bunsen reaction, hydrogen iodide and sulfuric acid, need to be allowed to stand and layer after reaching a certain concentration to separate hydrogen iodide and sulfuric acid, which brings certain difficulties to continuous production.

[0004] (2) The composition of boiler flue gas is complex, and the flue gas carries dust and nitrogen oxides. These impurities enter the Bunsen reaction of the sulfur-iodine cycle for hydrogen production, which brings difficulties to the purification of hydrogen iodide: (3) Iodine is a relatively volatile substance. The escape of iodine vapor will cause pollution. At the same time, the value of iodine is relatively high, and the escape of iodine vapor will increase the cost of hydrogen production. Summary of the Invention

[0005] The present invention aims at the problems existing in the current hydrogen production by absorbing sulfur dioxide in boiler flue gas with sulfur, and provides a system and method for continuously producing hydrogen iodide solution.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A system for continuously producing hydrogen iodide solution includes a separation tank, an absorption tower and a circulation pump; two isolation baffles are arranged in the middle of the separation tank, dividing the separation tank into three small tanks, namely a left small tank, a middle small tank and a right small tank. The height of the isolation baffle is not higher than two-thirds of the height of the surrounding walls of the separation tank. The discharge port of the absorption tower is placed in the left small tank, the outlet of the circulation pump is connected to the first inlet of the absorption tower, and the suction port of the circulation pump is placed in the right small tank. The mixed liquid discharged from the absorption tower first enters the left small tank. When the left small tank is full of the mixed liquid, it overflows to the middle small tank. When the middle small tank is full of the mixed liquid, it overflows to the right small tank and enters the suction port of the circulation pump. And the height of the isolation baffle is not lower than the discharge port of the absorption tower and the suction port of the circulation pump, and the distance between the two isolation baffles is not less than three times the height of the isolation baffle.

[0007] A further improvement of the present invention is that the separation tank is a rectangular tank.

[0008] A further improvement of the present invention is that it further includes a separation device, a sulfuric acid storage tank, and a distillation section; The separation device has an inlet at the topmost part, connected to the bottom of the middle small pool of the separation tank. It has two outlets. The first outlet is at the bottommost part of the separation device and is connected to the inlet of the distillation section. The second outlet is on the side wall of the upper middle part of the separation device and is connected to the inlet of the sulfuric acid storage tank.

[0009] A further improvement of the present invention is that the separation device is an elongated container.

[0010] A further improvement of the present invention is that it further includes a bottom kettle discharge pump, a bottom kettle, a stripping section, a rectifying section, and a hydrogen iodide decomposition device; The bottom kettle is installed at the bottom of the distillation section. The outlet of the bottom kettle is connected to the inlet of the bottom kettle discharge pump. The outlet of the bottom kettle discharge pump is connected to the first inlet of the separation tank. The outlet of the distillation section is connected to the inlet of the rectifying section. The outlet of the rectifying section is divided into two branches. The first branch is connected to the inlet of the stripping section, and the second branch is connected to the inlet of the bottom kettle. The outlet of the stripping section is connected to the inlet of the hydrogen iodide decomposition device.

[0011] A further improvement of the present invention is that it further includes an iodine addition device and a hydrogen storage device. The first outlet of the hydrogen iodide decomposition device is connected to the inlet of the hydrogen storage device. The second outlet of the hydrogen storage device and the outlet of the iodine addition device are combined into one branch and connected to the second inlet of the separation tank.

[0012] A further improvement of the present invention is that it further includes a flue after the induced draft fan, a water replenishing device, a washing device, a water treatment device, an iodine interception device, and a flue gas emission device; The outlet of the flue after the induced draft fan is connected to the first inlet of the washing device. The outlet of the water replenishing device is connected to the second inlet of the washing device. The first outlet of the washing device is connected to the inlet of the water treatment device. The outlet of the water treatment device is connected to the second inlet of the iodine interception device. The second outlet of the washing device is connected to the second inlet of the absorption tower. The second outlet of the absorption tower is connected to the first inlet of the iodine interception device. The first outlet of the iodine interception device is connected to the right small pool of the separation tank. The second outlet of the iodine interception device is connected to the inlet of the flue gas emission device.

[0013] A method for continuously producing a hydrogen iodide solution, which is based on the system for continuously producing a hydrogen iodide solution as described above, includes: Before the system is started, clear water is injected into the washing device through the water replenishing device. At the same time, water is injected from the washing device to the iodine interception device through the water treatment device, and water is injected from the iodine interception device to the separation tank. After the water levels in the three small pools of the separation tank are all higher than the partition board, the circulation pump is started. During this process, water is replenished to the washing device, the iodine interception device, and the separation tank until the water levels in the washing device, the iodine interception device, and the separation tank are normal, and then the washing device and the iodine interception device are started; Iodine is added to the separation tank by an iodine addition device until the solution in the separation tank reaches iodine saturation; The flue gas from the flue after the induced draft fan is introduced into the washing device. After washing, the flue gas enters the absorption tower. Sulfur dioxide in the flue gas reacts with the iodine solution coming from the circulation pump. Sulfur dioxide is consumed, producing a hydrogen iodide solution and a sulfuric acid solution; The flue gas that has removed sulfur dioxide and comes out of the absorption tower enters the iodine blocking device. The solution in the iodine blocking tower absorbs the iodine that escapes from the absorption tower, and then the flue gas enters the flue gas emission device; After the water in the washing device washes the flue gas, the water quality deteriorates. After being treated by the water treatment device to be qualified, it replenishes the water shortage of the iodine blocking device and at the same time replenishes the water shortage of the washing device; As the iodine solution in the separation tank absorbs sulfur dioxide in the flue gas, the concentrations of hydrogen iodide and sulfuric acid in the separation tank increase. Hydrogen iodide dissolves more iodine, resulting in a larger density difference between the hydrogen iodide and iodine solution and the sulfuric acid solution. When the solution in the left small tank passes through the middle small tank, the solution with a larger density sinks to the middle small tank, causing the density of the solution in the middle small tank to continuously increase. When the density of the solution at the bottom of the middle small tank is greater than 1.8 kg / L, the solution at the lower part of the middle small tank is discharged into the separation device. During this process, the corresponding water is replenished to keep the water levels of each device normal. The solution discharged into the separation device is separated into a sulfuric acid solution, a hydrogen iodide and iodine solution. The sulfuric acid solution enters the sulfuric acid storage tank, and the hydrogen iodide and iodine solution enter the distillation section; The solution entering the distillation section obtains a pure high-concentration hydrogen iodide solution after passing through the rectification section and the stripping section. Part of the hydrogen iodide solution decomposes in the hydrogen iodide decomposition device, producing hydrogen. The hydrogen enters the hydrogen storage device, and the remaining iodine and hydrogen iodide solution return to the separation tank; The mixed liquid discharged from the separation device into the distillation section, after extracting part of the hydrogen iodide, the remaining liquid enters the bottom of the tower, and is discharged into the separation tank by the bottom discharge pump of the tower.

[0014] A further improvement of the present invention is that it further includes: paying attention to monitoring the remaining iodine in the separation tank, and adding iodine immediately when the iodine in the separation tank is dissolved, so that the solution in the separation tank is in an iodine-saturated state.

[0015] A further improvement of the present invention is that it further includes: paying attention to monitoring the liquid levels of the separation tank, the iodine blocking device, and the washing device, making the liquid levels of each device normal, and replenishing in time when the liquid level is low.

[0016] Compared with the prior art, the present invention has at least the following beneficial technical effects: A system capable of continuously producing hydrogen iodide solution provided by the present invention divides the separation pool into a left small pool, a middle small pool, and a right small pool by an isolation baffle. The left small pool is used to receive the absorption liquid returned from the absorption tower, and the suction inlet of the circulation pump is arranged in the right small pool. In this way, the liquid in the middle small pool is not disturbed by the inflow and outflow of liquid and is in a relatively static state. There are certain distance requirements for the middle small pool. During the process of the mixed liquid flowing from the left small pool through the middle small pool to the right small pool, the liquid with a large density will sink to the bottom of the middle small pool, and the liquid with a small density will float upward due to the extrusion of the liquid with a large density. During the continuous production process, stratification of the mixed liquid is formed in the middle small pool.

[0017] Furthermore, a system capable of continuously producing hydrogen iodide solution provided by the present invention further includes a separation device. When the density of the mixed liquid in the middle small pool is greater than 1.8 kg / L, the solution at the lower part of the middle small pool is slowly discharged into the separation device for further standing, stratifying, and separating. In this way, the separation is isolated from the continuous production, so that the continuous production and the separation do not interfere with each other.

[0018] Furthermore, a system capable of continuously producing hydrogen iodide solution provided by the present invention further includes a washing tower, an absorption tower, an iodine interception tower, and a flue gas detection and emission device. Since the flue gas components of the boiler are complex, by setting up the washing tower, most of the dust and nitrogen oxides in the flue gas can be washed, reducing the influence of these impurities on the absorption of iodine by sulfur dioxide; in order to reduce the escape of iodine, the present invention sets up an iodine interception tower, reducing the probability of iodine escaping from the system; at the same time, the slurry for intercepting iodine is supplemented into the absorption tower, reducing the use of fresh water and the generation of waste water, which is more environmentally friendly; finally, the flue gas is washed three times by the washing tower, the absorption tower, and the iodine interception tower, making it cleaner and more environmentally friendly.

[0019] Furthermore, a system capable of continuously producing hydrogen iodide solution provided by the present invention further includes a fresh water tank, a waste liquid tank, and a washing tower circulation pump. Fresh water can be injected into the washing tower and the iodine interception tower respectively through the fresh water tank. The waste liquid tank is used to collect the slurry discharged from the washing tower, and the circulation of the washing tower can be accelerated through the washing tower circulation pump.

[0020] A method for continuously producing hydrogen iodide solution provided by the present invention, the setting of the separation pool enables the continuous production and the separation to complement and interfere with each other, and proceed synchronously, improving the utilization efficiency of the system and not affecting the continuous production of electricity; the washing tower can wash most of the dust and nitrogen oxides in the flue gas, reducing the influence of these impurities on the absorption of iodine by sulfur dioxide; in order to reduce the escape of iodine, the present invention reduces the probability of iodine escaping from the system through the iodine interception tower; at the same time, the slurry for intercepting iodine is supplemented into the absorption tower, reducing the use of fresh water and the generation of waste water, which is more environmentally friendly; finally, the flue gas is washed three times by the washing tower, the absorption tower, and the iodine interception tower, making it cleaner and more environmentally friendly. Description of the Drawings

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a structural block diagram of a system for continuously producing hydrogen iodide solution according to the present invention.

[0023] Explanation of reference numerals: 1. Separation tank, 2. Absorption tower, 3. Circulation pump, 4. Separation device, 5. Sulfuric acid storage tank, 6. Bottom discharge pump of the tower, 7. Tower kettle, 8. Distillation section, 9. Stripping section, 10. Rectifying section, 11. Hydrogen iodide decomposition device, 12. Iodine addition device, 13. Flue after the induced draft fan, 14. Water replenishing device, 15. Washing device, 16. Water treatment device, 17. Iodine blocking device, 18. Flue gas emission device, 19. Hydrogen storage device. Specific embodiments

[0024] In the following text, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0025] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0026] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0027] In the present invention, unless otherwise clearly specified or limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0029] It should also be understood that the terms used in the specification of the present invention are merely for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0030] It should be further understood that the term " / and" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0031] Structural schematic diagrams according to various disclosed embodiments of the present invention are shown in the drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are merely exemplary, and may actually deviate due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes and relative positions according to actual needs.

[0032] The embodiments of the present invention will be described in detail below with reference to the drawings.

[0033] Embodiment 1 As Figure 1As shown in the figure, a system for continuously producing hydrogen iodide solution provided by the present invention includes a separation tank 1, an absorption tower 2, and a circulation pump 3; the separation tank 1 is a rectangular tank, and 2 isolation baffles are arranged in the middle of the separation tank 1, dividing the separation tank into 3 small tanks, namely the left small tank, the middle small tank, and the right small tank. The height of the isolation baffle is not higher than two-thirds of the height of the surrounding walls of the separation tank 1. The discharge port of the absorption tower 2 is placed in the left small tank, the outlet of the circulation pump 3 is connected to the first inlet of the absorption tower 2, and the suction port of the circulation pump 3 is placed in the right small tank. The mixed liquid discharged from the absorption tower 2 first enters the left small tank. When the left small tank is full of the mixed liquid, it overflows to the middle small tank. When the middle small tank is full of the mixed liquid, it overflows to the right small tank and enters the suction port of the circulation pump 3. And the height of the isolation baffle is not lower than the discharge port of the absorption tower 2 and the suction port of the circulation pump 3, and the distance between the two isolation baffles is not less than 3 times the height of the isolation baffle.

[0034] In this embodiment, it further includes a separation device 4, a sulfuric acid storage tank 5, and a distillation section 8; the separation device 4 is a slender container. The separation device 4 has an inlet at its topmost part, which is connected to the bottom of the middle small tank of the separation tank 1, and has two outlets. The first outlet is at the bottommost part of the separation device 4 and is connected to the inlet of the distillation section 8, and the second outlet is on the side wall of the upper middle part of the separation device 4 and is connected to the inlet of the sulfuric acid storage tank 5.

[0035] In this embodiment, it further includes a bottom discharge pump 6, a reboiler 7, a stripping section 9, a rectifying section 10, and a hydrogen iodide decomposition device 11; the reboiler 7 is installed at the bottom of the distillation section 8. The outlet of the reboiler 7 is connected to the inlet of the bottom discharge pump 6, the outlet of the bottom discharge pump 6 is connected to the first inlet of the separation tank 1, the outlet of the distillation section 8 is connected to the inlet of the rectifying section 10, the outlet of the rectifying section 10 is divided into two branches. The first branch is connected to the inlet of the stripping section 9, and the second branch is connected to the inlet of the reboiler 7. The outlet of the stripping section 9 is connected to the inlet of the hydrogen iodide decomposition device 11.

[0036] In this embodiment, it further includes an iodine addition device 12 and a hydrogen storage device 19. The first outlet of the hydrogen iodide decomposition device 11 is connected to the inlet of the hydrogen storage device 19, and the second outlet of the hydrogen storage device 19 and the outlet of the iodine addition device 12 are combined into one branch and connected to the second inlet of the separation tank 1.

[0037] In this embodiment, it further includes the flue duct 13 behind the induced draft fan, the water replenishing device 14, the washing device 15, the water treatment device 16, the iodine blocking device 17 and the flue gas discharging device 18; the outlet of the flue duct 13 behind the induced draft fan is connected to the first inlet of the washing device 15, the outlet of the water replenishing device 14 is connected to the second inlet of the washing device 15, the first outlet of the washing device 15 is connected to the inlet of the water treatment device 16, the outlet of the water treatment device 16 is connected to the second inlet of the iodine blocking device 17, the second outlet of the washing device 15 is connected to the second inlet of the absorption tower 2, the second outlet of the absorption tower 2 is connected to the first inlet of the iodine blocking device 17, the first outlet of the iodine blocking device 17 is connected to the right small pool of the separation tank 1, and the second outlet of the iodine blocking device 17 is connected to the inlet of the flue gas discharging device 18.

[0038] Embodiment 2 As Figure 1 shown, a method for continuously producing hydrogen iodide solution provided by the present invention includes: Before the system starts, inject clear water into the washing device 15 through the water replenishing device 14. At the same time, inject water from the washing device 15 into the iodine blocking device 17 through the water treatment device 16, and at the same time, inject water from the iodine blocking device 17 into the separation tank 1. After the water levels of the three small pools in the separation tank 1 are all higher than the partition board, start the circulation pump 3. During this process, replenish water to the washing device 15, the iodine blocking device 17 and the separation tank 1 until the water levels of the washing device 15, the iodine blocking device 17 and the separation tank 1 are normal, and then start the washing device 15 and the iodine blocking device 17; Add iodine to the separation tank 1 by the iodine adding device 12 until the solution in the separation tank 1 reaches iodine saturation; Introduce the flue gas from the flue duct 13 behind the induced draft fan into the washing device 15. The washed flue gas enters the absorption tower 2. Sulfur dioxide in the flue gas reacts with the iodine solution coming from the circulation pump 3, and sulfur dioxide is consumed, generating hydrogen iodide solution and sulfuric acid solution; The flue gas coming out of the absorption tower 2 after removing sulfur dioxide enters the iodine blocking device 17. The flue gas in the iodine blocking tower 17 after the solution in it absorbs the iodine escaping from the absorption tower 2 enters the flue gas discharging device 18; After the water in the washing device 15 washes the flue gas, the water quality deteriorates. After being treated by the water treatment device 16 to be qualified, it replenishes the water shortage of the iodine blocking device 17 and at the same time replenishes the water shortage of the washing device 15; As the iodine solution in the separation tank 1 absorbs sulfur dioxide in the flue gas, the concentrations of hydrogen iodide and sulfuric acid in the separation tank 1 increase. More iodine is dissolved in the hydrogen iodide, resulting in a larger density difference between the hydrogen iodide and iodine solution and the sulfuric acid solution. When the solution in the left small tank passes through the middle small tank, the solution with a larger density sinks to the middle small tank, causing the density of the solution in the middle small tank to continuously increase. When the density of the solution at the bottom of the middle small tank is greater than 1.8 kg / L, the solution at the lower part of the middle small tank is discharged into the separation device 4. During this process, corresponding water is supplemented to keep the water levels of each device normal. The solution discharged into the separation device 4 is separated into a sulfuric acid solution, hydrogen iodide, and iodine solution. The sulfuric acid solution enters the sulfuric acid storage tank 5, and the hydrogen iodide and iodine solution enter the distillation section 8; The solution entering the distillation section 8 obtains a pure high-concentration hydrogen iodide solution after passing through the rectification section 10 and the stripping section 9. Part of the hydrogen iodide solution decomposes in the hydrogen iodide decomposition device 11 to produce hydrogen, and the hydrogen enters the hydrogen storage device 19. The remaining iodine and hydrogen iodide solution return to the separation tank 1; The mixed liquid discharged from the separation device 4 into the distillation section 8 enters the reboiler 7 after extracting part of the hydrogen iodide, and the remaining liquid is discharged into the separation tank 1 by the reboiler discharge pump 6.

[0039] In this embodiment, pay attention to monitoring the remaining iodine in the separation tank 1. Even if iodine is added after the iodine in the separation tank 1 is dissolved, the solution in the separation tank 1 is kept in an iodine-saturated state.

[0040] In this embodiment, pay attention to monitoring the liquid level of the separation tank 1, the liquid level of the iodine-blocking device 17, and the liquid level of the washing device 15 to keep each liquid level normal and supplement it in time when the liquid level is low.

[0041] Embodiment 3 In this embodiment, a 350 MW thermal power unit has 5 g of sulfur dioxide and 30 mg of dust per cubic meter of flue gas, and the total flue gas volume is 1.3 million m³ / h.

[0042] After the flue gas passes through the washing tower 2, sulfur dioxide and dust in the flue gas are absorbed by the washing water. After the sulfur dioxide in the water in the washing tower 2 reaches saturation, the sulfur dioxide enters the absorption tower 3. When the slurry in the washing tower 2 is viscous, affecting the washing effect of dust or the normal operation of the washing tower circulation pump 9, the slurry in the washing tower 2 is replaced.

[0043] In the absorption tower 3, sulfur dioxide reacts with iodine and water to produce hydrogen iodide. Subsequently, hydrogen is produced from hydrogen iodide. In theory, for a 350 MW thermal power unit at full load, sulfur dioxide in the flue gas can produce 100,000 mol of hydrogen per hour and 2,240 m³ of hydrogen per hour. Calculated at 10 yuan per cubic meter of hydrogen, the value is 22,000 yuan; it can produce 100,000 mol of sulfuric acid per hour and 9.8 t of sulfuric acid per hour. Calculated at 500 yuan per ton of sulfuric acid, the value is 4,900 yuan; the heat required to decompose hydrogen iodide is 17,002.6 mj / h, accounting for less than 1% of the heat of the boiler flue gas, showing good economic benefits.

[0044] The flue gas coming out of the absorption tower 3 enters the iodine-blocking tower 4, and the trace iodine, hydrogen iodide, and sulfuric acid it carries are absorbed by the liquid in the iodine-blocking tower 4. The flue gas discharged from the iodine-blocking tower 4 is clean flue gas.

[0045] The above has shown and described the basic principles, main features, and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic features of the present invention, the present invention can be implemented in other specific forms. Therefore, from any perspective, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0046] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A system capable of continuously producing a hydrogen iodide solution, characterized in that: It comprises a separation tank (1), an absorption tower (2) and a circulation pump (3); Two isolation baffles are arranged in the middle of the separation pool (1) to divide the separation pool into three small pools, namely a left small pool, a middle small pool and a right small pool. The height of the isolation baffles is not higher than two-thirds of the height of the surrounding walls of the separation pool (1). The discharge outlet of the absorption tower (2) is placed in the left small pool. The outlet of the circulation pump (3) is connected to the first inlet of the absorption tower (2). The suction port of the circulation pump (3) is placed in the right small pool. The mixed liquid discharged from the absorption tower (2) first enters the left small pool. After the mixed liquid in the left small pool is full, it overflows to the middle small pool. After the mixed liquid in the middle small pool is full, it overflows to the right small pool and enters the suction port of the circulation pump (3). The height of the isolation baffles is not lower than the discharge outlet of the absorption tower (2) and the suction port of the circulation pump (3). The distance between the two isolation baffles is not less than 3 times the height of the isolation baffles.

2. A system capable of continuously producing hydrogen iodide solution according to claim 1, characterized in that: The separation tank (1) is a rectangular tank.

3. A system capable of continuously producing hydrogen iodide solution according to claim 1, characterized in that: It also includes a separation device (4), a sulfuric acid storage tank (5) and a distillation section (8); The separation device (4) has an inlet at the top of the separation device (4) connected to the bottom of the middle small pool of the separation pool (1), and two outlets, the first outlet is at the bottom of the separation device (4) connected to the inlet of the distillation section (8), and the second outlet is on the side wall of the upper middle part of the separation device (4) connected to the inlet of the sulfuric acid storage tank (5).

4. A system capable of continuously producing hydrogen iodide solution according to claim 3, characterized in that: The separation device (4) is an elongated container.

5. A system capable of continuously producing hydrogen iodide solution according to claim 3, characterized in that: It also includes a tower bottom discharge pump (6), a tower bottom (7), a stripping section (9), a rectifying section (10) and a hydrogen iodide decomposition device (11); The tower kettle (7) is installed at the bottom of the distillation section (8), the outlet of the tower kettle (7) is connected to the inlet of the tower kettle discharge pump (6), the outlet of the tower kettle discharge pump (6) is connected to the first inlet of the separation tank (1), the outlet of the distillation section (8) is connected to the inlet of the distillation section (10), the outlet of the distillation section (10) is divided into two streams, the first stream is connected to the inlet of the stripping section (9), and the second stream is connected to the inlet of the tower kettle (7), and the outlet of the stripping section (9) is connected to the inlet of the hydrogen iodide decomposition device (11).

6. A system capable of continuously producing hydrogen iodide solution according to claim 5, characterized in that: It also includes an iodine adding device (12) and a hydrogen storage device (19), wherein the first outlet of the hydrogen iodide decomposition device (11) is connected to the inlet of the hydrogen storage device (19), and the second outlet of the hydrogen storage device (19) and the outlet of the iodine adding device (12) are combined into one stream and connected to the second inlet of the separation tank (1).

7. A system capable of continuously producing hydrogen iodide solution according to claim 6, characterized in that: It also includes a flue gas duct after the induced draft fan (13), a water replenishing device (14), a washing device (15), a water treatment device (16), an iodine intercepting device (17) and a flue gas exhaust device (18); The outlet of the flue (13) after the induced draft fan is connected to the first inlet of the washing device (15), the outlet of the water replenishing device (14) is connected to the second inlet of the washing device (15), the first outlet of the washing device (15) is connected to the inlet of the water treatment device (16), the outlet of the water treatment device (16) is connected to the second inlet of the iodine intercepting device (17), the second outlet of the washing device (15) is connected to the second inlet of the absorption tower (2), the second outlet of the absorption tower (2) is connected to the first inlet of the iodine intercepting device (17), the first outlet of the iodine intercepting device (17) is connected to the small pool on the right side of the separation pool (1), and the second outlet of the iodine intercepting device (17) is connected to the inlet of the flue gas discharge device (18).

8. A method capable of continuously producing a hydrogen iodide solution, characterized in that: The method is based on a system capable of continuously producing a hydrogen iodide solution as described in claim 7, comprising: Before the system is started, clean water is injected into the washing device (15) through the water replenishing device (14), and water is injected into the iodine intercepting device (17) from the washing device (15) through the water treatment device (16), and water is injected into the separation tank (1) from the iodine intercepting device (17). After the water levels of the three small tanks of the separation tank (1) are higher than the isolation plate, the circulation pump (3) is started. In this process, the circulation pump (3) replenishes water to the washing device (15), the iodine intercepting device (17) and the separation tank (1) until the water levels of the washing device (15), the iodine intercepting device (17) and the separation tank (1) are normal, and the washing device (15) and the iodine intercepting device (17) are started; adding iodine to the separation tank (1) by the iodine adding device (12) until the solution in the separation tank (1) reaches iodine saturation; The flue gas from the flue duct (13) after the induced draft fan is introduced into the scrubbing device (15), and the scrubbed flue gas enters the absorption tower (2), where the sulfur dioxide in the flue gas reacts with the iodine solution from the circulation pump (3), the sulfur dioxide is consumed, and a hydrogen iodide solution and a sulfuric acid solution are produced; The flue gas from the absorption tower (2) after the sulfur dioxide is removed enters the iodine interception device (17), and the solution in the iodine interception tower (17) absorbs the iodine escaping from the absorption tower (2), and the flue gas enters the flue gas discharge device (18); After the water in the washing device (15) washes the flue gas, the water quality deteriorates. After being treated by the water treatment device (16) and passing the treatment, the water is used to supplement the water shortage in the iodine interception device (17) and the water shortage in the washing device (15); As the iodine solution in the separation tank (1) absorbs sulfur dioxide in the flue gas, the concentrations of hydrogen iodide and sulfuric acid in the separation tank (1) increase, and hydrogen iodide dissolves more iodine, causing the density difference between the hydrogen iodide and iodine solution and the sulfuric acid solution to increase. When the solution in the left small tank passes through the middle small tank, the solution with a higher density sinks to the middle small tank, causing the density of the solution in the middle small tank to increase continuously. When the density of the solution at the bottom of the middle small tank is greater than 1.8 kg / L, the solution at the bottom of the middle small tank is discharged into the separation device (4). During this process, corresponding water is added to keep the water level of each device normal. The solution discharged into the separation device (4) is separated into sulfuric acid solution and hydrogen iodide and iodine solution. The sulfuric acid solution enters the sulfuric acid storage tank (5), and the hydrogen iodide and iodine solution enter the distillation section (8); The solution entering the distillation section (8) is passed through the rectification section (10) and the stripping section (9) to obtain a pure high-concentration hydrogen iodide solution. The hydrogen iodide solution is partially decomposed in the hydrogen iodide decomposition device (11) to generate hydrogen gas, which enters the hydrogen storage device (19). The remaining iodine and hydrogen iodide solution are returned to the separation tank (1); The mixed liquid discharged from the separation device (4) into the distillation section (8) extracts part of the hydrogen iodide, and the remaining liquid enters the tower bottom (7), and is discharged into the separation tank (1) by the tower bottom discharge pump (6).

9. A method for continuously producing a hydrogen iodide solution according to claim 8, characterized in that: Also includes: Pay attention to monitoring the remaining iodine in the separation tank (1). When the iodine in the separation tank (1) is dissolved, add iodine so that the solution in the separation tank (1) is saturated with iodine.

10. A method for continuously producing a hydrogen iodide solution according to claim 8, characterized in that: Also includes: Pay attention to monitoring the liquid level of the separation tank (1), the liquid level of the iodine intercepting device (17), and the liquid level of the washing device (15) to ensure that each liquid level is normal and replenish it in time when the liquid level is low.

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