Trickle bed reactor for continuously producing calcium chloride solution through reaction of hydrochloric acid and limestone

Abstract

The invention relates to the technical field of chemical equipment, and mainly discloses a trickle bed reactor for continuously producing calcium chloride solution through reaction of hydrochloric acid and limestone, which comprises an upper cone, a barrel and an eccentric lower cone, an acid inlet pipe supporting grid is arranged below the acid inlet pipe to divide the area below the acid inlet pipe into a plurality of independent compartments, the concentration of hydrochloric acid in the compartments is high, the reaction speed is high, a pulse flow reaction area is formed, and acid liquid can be uniformly distributed; the area below the cells is low in hydrochloric acid concentration and is a trickling reaction area, so that full reaction of hydrochloric acid is facilitated; a limestone supporting grating is arranged between the barrel and the lower cone, and a discharging pipe and a hydraulic control discharging valve assembly are arranged at the bottom of the barrel; the reactor is provided with bottom, middle and top graded exhaust ports to reduce the gas flow rate in the reactor and reduce foam entrainment; the structure obviously improves the hydrochloric acid conversion rate and the reactor productivity, and is suitable for continuous industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical equipment, and specifically to a trickle bed reactor for continuously producing calcium chloride solution by the reaction of hydrochloric acid and limestone. Background Art

[0002] With the development of the chemical industry, the output of by-product hydrochloric acid has increased rapidly, and the outlet of by-product hydrochloric acid has become a major problem restricting the development of related enterprises. Since the process of producing calcium chloride by reacting by-product hydrochloric acid with limestone (calcium acid method) has a greater cost advantage compared with the traditional process of producing calcium chloride from soda ash wastewater by the ammonia-alkali method (ammonia-alkali method), the production capacity of calcium chloride by the calcium acid method has increased rapidly in recent years, while the production capacity of calcium chloride by the ammonia-alkali method has shrunk year by year. The existing production of calcium chloride by reacting hydrochloric acid with limestone generally adopts an intermittent process, which has problems such as low production efficiency and incomplete reaction of raw materials.

[0003] Patent CN207451634U discloses a continuous drainage moving bed reactor for the reaction of massive limestone with hydrochloric acid. The reactor main body consists of an upper cylinder and a conical cylinder connected to the upper cylinder. The upper part of the upper cylinder is provided with a limestone feed inlet and an exhaust port. The hydrochloric acid inlet pipe is arranged in the middle of the upper cylinder, and the bottom of the conical cylinder is a continuous drainage discharge port. Hydrochloric acid flows into the reactor from the hydrochloric acid inlet pipe and reacts with limestone, and the generated calcium chloride solution is directly discharged from the continuous drainage discharge port at the bottom of the cylinder, with sufficient reaction. This continuous flow reactor operates continuously and stably in actual application, has a high calcium acid conversion rate, and good use effect, but still has the following deficiencies: (1) The outlet of the above-mentioned moving bed reactor is calcium chloride liquid and unreacted limestone. It is necessary to set up a liquid-solid separation device and a return material device to recover limestone, resulting in many auxiliary devices of the reaction device, complex process, and increased production cost; (2) The reaction of calcium carbonate and hydrochloric acid to produce calcium chloride itself has a lot of foam and a lot of carbon dioxide. Therefore, the core of this process is defoaming work. The amount of carbon dioxide is a direct influencing factor for generating foam. The carbon dioxide generated by the reactor is directly discharged from the exhaust port at the top. The rapid rise of the carbon dioxide gas flow leads to entrainment of mist. In order to prevent excessive foam from being carried out by the carbon dioxide gas, it is necessary to control the acid inlet amount of the reactor, reducing the production intensity of the reactor; most of the space above the hydrochloric acid inlet pipe of the reactor is used for defoaming, resulting in low reactor use efficiency. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems existing in the prior art, and provides a trickle bed reactor for continuously producing calcium chloride solution by the reaction of hydrochloric acid and limestone. By optimizing the reactor structure, the generated calcium chloride solution is continuously discharged from the lower part of the reactor; the graded exhaust reduces the gas flow rate, reduces foam generation, removes acid mist, the reactor has a high production intensity, and a large output per unit cross-sectional area.

[0005] To achieve the above object, the present invention adopts the following technical solution: A trickle bed reactor for continuously producing calcium chloride solution by the reaction of hydrochloric acid and limestone, comprising an upper cone, a cylinder body and a lower cone arranged in sequence from top to bottom. The upper cone is a vertically placed cone structure, the cylinder body is a cylindrical structure, and the lower cone is an inverted cone structure; A limestone feed inlet and a top exhaust port are provided at the top of the upper cone, a calcium chloride solution outlet is provided at the bottom of the lower cone, a pressure sensor and a sight glass port are further provided at the top of the upper cone. The pressure sensor is used to monitor the internal pressure of the reactor, and the sight glass port is used to observe the foam height inside the upper cone. A manhole is provided below the cylinder body for the maintenance of the reactor; A limestone support grid is provided between the cylinder body and the lower cone to support the limestone layer and filter unreacted small limestone particles. An openable discharge pipe is provided at the bottom of the limestone support grid. The discharge pipe communicates the area above the limestone support grid with the area outside the lower cone, and the discharge pipe is used to discharge limestone slag; Two or more horizontally arranged hydrochloric acid inlet pipes are arranged side by side inside the cylinder body. A plurality of inlet holes are horizontally distributed on both sides of the hydrochloric acid inlet pipes. An inlet pipe support grid is provided below the hydrochloric acid inlet pipes. The inlet pipe support grid is used to support the hydrochloric acid inlet pipes and divide the area below the hydrochloric acid inlet pipes into several independent compartments. Preferably, the height of the partition rib plate is 400 mm to 800 mm.

[0006] A bottom exhaust port is provided on the lower cone, an upper air inlet is provided at the top of the cylinder body, a middle exhaust port is provided in the upper part of the cylinder body between the hydrochloric acid inlet pipes and the upper air inlet. The bottom exhaust port, the middle exhaust port and the upper air inlet are connected by a gas communication pipe, and a valve is provided between the bottom exhaust port and the middle exhaust port.

[0007] Through the above technical solution, limestone raw materials are put into and fill the inside of the reactor cylinder through the limestone feed inlet, and hydrochloric acid is continuously introduced through the acid inlet pipe. During the process of the hydrochloric acid flowing downward in the voids of the limestone packing layer, it reacts completely with the limestone. The hydrochloric acid concentration is high in the acid inlet pipe support grid below the hydrochloric acid inlet pipe, and the reaction rate is fast. A large amount of carbon dioxide gas generated by the reaction flows upward, forming a pulse flow pattern, creating a pulse flow reaction zone, achieving uniform distribution of the acid solution within the cross-section of this reaction zone. Most of the hydrochloric acid reacts with the limestone in this area; the hydrochloric acid concentration decreases in the area below the acid inlet pipe support grid, and the amount of carbon dioxide gas generated is small. The gas and liquid move downward in the same direction in the limestone packing layer, and the liquid phase fluid flows in a liquid film shape on the surface of the particles. The interaction between the gas and liquid phases is weak, forming a trickle flow pattern, creating a trickle flow reaction zone, and continuously ensuring full reaction between the hydrochloric acid and the limestone. In the area above the acid inlet pipe, the carbon dioxide comes into full contact with the limestone layer, playing an antifoaming role, serving as an antifoaming zone. The calcium chloride solution, sediment, and acid-insoluble substances generated by the reaction are discharged from the calcium chloride solution outlet, and the limestone consumed by the reaction falls from the limestone feed inlet for automatic replenishment.

[0008] Furthermore, through the above technical solution, a part of the carbon dioxide gas generated by the reaction in the pulse flow reaction zone flows upward in the cylinder, comes into full contact with the limestone packing layer above the hydrochloric acid inlet pipe to remove mist and acid mist, and then is discharged through the upper exhaust port at the top. At the same time, it is shunted through the middle exhaust port. Another part of the carbon dioxide gas flows downward with the generated calcium chloride solution and is discharged through the lower exhaust port installed in the lower cone. Since the upward speed of carbon dioxide in the reactor cylinder is reduced, the phenomenon of serious entrainment of reaction tail gas mist caused by reactor foaming is effectively controlled. The reactor has a high production intensity and a large output per unit cross-sectional area. By adjusting the valve opening to regulate the upward carbon dioxide gas volume, it is ensured that there is no foam on the surface of the limestone layer in the reactor.

[0009] A further solution of the present invention is that the middle exhaust port is arranged on the side close to the upper air inlet between the hydrochloric acid inlet pipe and the upper air inlet. The middle exhaust port cannot be too close to the hydrochloric acid inlet pipe to avoid premature entry of unreacted acid solution into the middle exhaust port and being discharged with carbon dioxide.

[0010] A further solution of the present invention is that the hydrochloric acid inlet pipe is arranged in the upper middle part of the cylinder. The volume of the trickle flow reaction zone is large, and the volume of the antifoaming zone is small, improving the volume utilization rate of the reactor.

[0011] A further solution of the present invention is that a baffle is provided above the hydrochloric acid inlet pipe. Preferably, the cross-section of the baffle is an inverted V shape, the center line of the baffle is in the same vertical plane as the axis of the hydrochloric acid inlet pipe, and the width of the bottom of the baffle is 2 to 5 times the diameter of the hydrochloric acid inlet pipe. The inverted V-shaped baffle is used to protect the hydrochloric acid inlet pipe from being impacted and worn by limestone on the one hand, and on the other hand, to ensure that the acid solution sprayed from the acid inlet hole directly enters the independent compartment of the inlet pipe support grid below the hydrochloric acid inlet pipe, and quickly realizes the uniform distribution of the acid solution in the cross-section of the reactor during the interaction with the rising carbon dioxide gas.

[0012] A further solution of the present invention is that the inlet pipe support grid forms a plurality of independent compartments through partition ribs, and the independent compartments close to the inner wall of the cylinder are separated from the inner wall of the cylinder by partition ribs. By adopting this solution, it is possible to prevent the acid solution from flowing along the inner wall of the reactor cylinder to form a short circuit.

[0013] Preferably, two groups of hydrochloric acid inlet pipes are provided, and the two groups of hydrochloric acid inlet pipes are symmetrically distributed along the diameter of the cross-section of the cylinder. Since the volume of the independent compartment in the middle of the cylinder is larger and the volume of the independent compartment at the edge of the cylinder is smaller, the number of acid inlet holes of the hydrochloric acid inlet pipe facing the center of the cylinder is greater than the number of acid inlet holes facing the inner wall of the cylinder. By adopting this solution, the acid solution can be further evenly distributed in the independent compartment.

[0014] Preferably, 2 to 6 acid inlet holes are correspondingly provided for each independent compartment located in the middle of the cylinder between the two groups of hydrochloric acid inlet pipes, and 1 to 3 acid inlet holes are correspondingly provided for each independent compartment located at the edge of the cylinder for each group of hydrochloric acid inlet pipes. Preferably, the diameter of the acid inlet hole is 12 mm to 20 mm.

[0015] Preferably, the bottom of the limestone support grid is supported by support ribs, the distance between the grid plates of the limestone support grid is 12 mm to 30 mm, and a discharge hole is opened at the center of the limestone support grid and connected to a discharge pipe.

[0016] A further solution of the present invention is that the lower cone is an inverted eccentric cone. Preferably, the calcium chloride solution outlet is arranged at the lowest point of the lower cone, a flushing liquid port is arranged at the maximum value of the connection line between the calcium chloride solution outlet and the top surface of the lower cone, and a bottom exhaust port is arranged at the minimum value of the connection line between the calcium chloride solution outlet and the top surface of the lower cone. By adopting the above solution, the sediment, acid-insoluble substances and calcium chloride solution flow down along the inner wall of the eccentric cone, and less sediment and acid-insoluble substances will adhere to the surface with a smaller slope, and there will be basically no residue on the surface with a larger slope. Therefore, setting the flushing liquid port at this position can clean the residues on the surface with a smaller slope to the greatest extent, and setting the bottom exhaust port at the position with the largest slope facilitates the discharge of carbon dioxide gas from here.

[0017] A further solution of the present invention is that a blind plate is installed at the discharging end of the discharging pipe, and a discharging valve assembly is provided at the feeding end. When discharging materials during shutdown, the blind plate is removed and the discharging valve assembly is opened, so that the limestone in the reactor can be discharged. The discharging valve assembly includes a hydraulic cylinder, a valve rod, a slideway and a valve plate. The valve plate is arranged between the limestone supporting grille and the discharging pipe. The slideway is arranged on the supporting rib plate. One end of the valve plate is connected to the valve rod, and the valve plate is slidably connected to the slideway. The hydraulic cylinder drives the valve rod to move, thereby driving the valve plate to move along the slideway.

[0018] Preferably, there is a gap between the upper edge of the valve plate and the lower edge of the limestone supporting grille, and the gap is 5 mm to 20 mm.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Through the staged exhaust design, the present invention diverts carbon dioxide gas to be discharged at different heights, reduces the rising speed of the gas in the cylinder, avoids the generation of a large amount of foam and entrainment of mist due to too fast rising air flow speed, improves the operation stability of the reactor. The bottom exhaust port, the middle exhaust port and the upper air inlet are connected in series through a gas communication pipe, and the valve adjusts the diversion ratio. The staged exhaust system significantly reduces the entrainment of foam and acid mist and improves the output per unit cross-sectional area of the reactor.

[0020] 2. The acid inlet pipe supporting grille of the present invention divides the inside of the cylinder into several independent compartments through the partition rib plates, and the acid inlet holes on both sides of the hydrochloric acid inlet pipe are arranged according to regional differences; the independent compartments limit the flow path of the acid liquid, avoid the acid liquid flowing along the inner wall of the cylinder to form a "short circuit", and the acid inlet holes in the middle compartment are densely sprayed, and the edge sparse holes are supplemented to ensure that the acid liquid evenly covers the limestone filler layer on the cross section, and the reaction conversion rate is increased to pH>4.0.

[0021] 3. The lower cone of the present invention is an eccentric structure. The calcium chloride solution outlet is located at the lowest point, the flushing liquid port is arranged on the side with the smallest slope, and the bottom exhaust port is located on the side with the largest slope. The sediment and acid-insoluble substances flow along the eccentric conical surface to the outlet naturally with the calcium chloride solution generated by the reaction. The residues on the side with a smaller slope are flushed regularly by the flushing liquid port to prevent material accumulation inside the lower cone.

[0022] 4. The inside of the acid inlet pipe supporting grille of the present invention is a pulse flow area, and the lower part is a trickle flow area. The pulse flow area forms turbulence through a high gas velocity and quickly consumes a large amount of hydrochloric acid. The trickle flow area prolongs the reaction time to ensure complete conversion of hydrochloric acid.

[0023] 5. The limestone layer on the limestone supporting grille of the present invention plays a filtering role for the reaction product liquid. As the reaction progresses, the particle size of the massive limestone gradually decreases. The unreacted small limestone particles are blocked in the tortuous channels between the limestones in the filler layer and can continue to react with hydrochloric acid, while the sediment and acid-insoluble substances in the limestone flow out with the reaction product liquid, realizing continuous slag discharge of the reactor, and the reaction conversion rate of the limestone is close to 100%.

[0024] 6. An inverted V-shaped baffle is arranged above the hydrochloric acid inlet pipe, with the bottom width being 2 - 5 times the pipe diameter, and the center line being aligned with the axis of the inlet pipe. The baffle disperses the pressure of the limestone above, preventing the impact and abrasion of the inlet pipe; its inverted V-shaped structure forms a free space around the inlet pipe, and the acid liquid is sprayed horizontally into the independent compartment, which is conducive to the rapid distribution of hydrochloric acid across the reactor cross-section and improves the utilization rate of the reaction zone. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic diagram of the overall structure of the reactor of the present invention; Figure 2 It is a top view of the reactor of the present invention; Figure 3 For the present invention Figure 1 It is a schematic cross-sectional view along the A - A direction in the present invention; Figure 4 For the present invention Figure 1 It is a partial schematic cross-sectional view along the B - B direction in the present invention; Figure 5 For the present invention Figure 1 It is a schematic cross-sectional view along the C - C direction in the present invention; Figure 6 For the present invention Figure 5 It is a partial schematic cross-sectional view along the D - D direction in the present invention.

[0027] In the figures, 1. upper cone; 2. cylinder; 3. lower cone; 4. limestone support grid; 5. hydrochloric acid inlet pipe; 6. baffle; 7. inlet pipe support grid; 8. discharge pipe; 9. discharge valve assembly; 10. bottom exhaust port; 11. middle exhaust port; 12. upper air inlet; 13. gas communication pipe; 14. valve; 15. calcium chloride solution outlet; 16. limestone feed port; 17. top exhaust port; 18. flushing liquid port; 19. hydrochloric acid feed port; 20. discharge valve port; 21. manhole; 22. pressure sensor; 23. sight glass port; 24. independent compartment; 25. partition rib plate; 26. support rib plate; 27. hydraulic cylinder; 28. valve stem; 29. slideway; 30. valve plate. Detailed Embodiments

[0028] In order to better understand the above technical solutions, the following will describe the above technical solutions in detail in combination with the drawings of the specification and specific embodiments.

[0029] Figures 1-6 An embodiment of the present invention is shown.

[0030] As Figure 1 shown, this embodiment provides a trickle bed reactor for continuously producing calcium chloride solution by the reaction of hydrochloric acid and limestone, which includes an upper cone 1, a cylinder 2, and a lower cone 3 arranged in sequence from top to bottom. Specifically, the upper cone 1 is a right-side-up cone structure, the cylinder 2 is a cylindrical structure, and the lower cone 3 is an inverted cone structure.

[0031] As Figure 2 shown, a limestone feed inlet 16 and a top exhaust port 17 are provided at the top of the upper cone 1, a calcium chloride solution outlet 15 is provided at the bottom of the lower cone 3, a pressure sensor 22 and a sight glass port 23 are further provided at the top of the upper cone 1. The pressure sensor 22 is used to monitor the internal pressure of the reactor, and the sight glass port 23 is used to observe the foam situation inside the upper cone 1. A manhole 21 is provided below the cylinder 2 for the maintenance of the reactor. Those skilled in the art can change the installation positions of the above-mentioned limestone feed inlet, top exhaust port 17, calcium chloride solution outlet 15, pressure sensor 22, sight glass port 23, manhole 21, etc. according to needs. This embodiment is only an installation example of the above structures, and does not limit their specific installation positions and installation heights.

[0032] As Figure 1 shown, a limestone support grid 4 is provided between the cylinder 2 and the lower cone 3 to support the limestone layer. A discharge pipe 8 that can be opened and closed is provided at the bottom of the limestone support grid 4. The discharge pipe 8 communicates the area above the limestone support grid 4 with the area outside the lower cone 3. The discharge pipe 8 is used to discharge the unreacted limestone in the reactor when the machine is stopped.

[0033] As Figure 3 shown, in this embodiment, two or more groups of horizontally arranged hydrochloric acid inlet pipes 5 are arranged side by side on the cylinder 2. The hydrochloric acid inlet pipes 5 are detachably inserted into the inside of the cylinder 2 through a hydrochloric acid feed port 19. Preferably, in this embodiment, the hydrochloric acid inlet pipes 5 are arranged in the upper middle part of the cylinder 2, which increases the volume of the reaction zone and improves the volume utilization rate of the reactor. A plurality of acid inlet holes are horizontally distributed on both sides of the inlet pipe. In this embodiment, two groups of hydrochloric acid inlet pipes 5 are provided, and the two groups of hydrochloric acid inlet pipes 5 are symmetrically distributed along the diameter of the cross-section of the cylinder 2.

[0034] As Figure 3 、 Figure 4 shown, an inlet pipe support grid 7 is provided below the hydrochloric acid inlet pipe 5. The inlet pipe support grid 7 is used to support the hydrochloric acid inlet pipe 5 and divides the area below the hydrochloric acid inlet pipe 5 into several independent compartments 24.

[0035] Specifically, the acid inlet pipe support grid 7 forms a plurality of independent compartments 24 through the partition rib plates 25. The independent compartments 24 close to the inner wall of the cylinder body 2 are separated from the inner wall of the cylinder body 2 by the partition rib plates 25. Adopting this solution can prevent the acid solution from flowing along the inner wall of the reactor cylinder body 2 to form a short circuit. Since the cross-sectional area of the independent compartments 24 in the middle of the cylinder body 2 is larger and the cross-sectional area of the independent compartments 24 at the edge of the cylinder body 2 is smaller, the number of acid inlet holes of the hydrochloric acid inlet pipe 5 facing the center of the cylinder body 2 is greater than the number of acid inlet holes facing the inner wall of the cylinder body 2. Adopting this solution can further evenly distribute the acid solution in the independent compartments 24.

[0036] Preferably, 2 to 4 acid inlet holes are correspondingly arranged in each independent compartment 24 located in the middle of the cylinder body 2 between the two groups of hydrochloric acid inlet pipes 5, and 1 to 2 acid inlet holes are correspondingly arranged in each independent compartment 24 located at the edge of the cylinder body 2 for each group of hydrochloric acid inlet pipes 5. Preferably, the diameter of the acid inlet holes is 12 mm to 20 mm. Preferably, the height of the partition rib plates 25 is 400 mm to 800 mm. In this embodiment, the number of acid inlet holes of the hydrochloric acid inlet pipe 5 facing the center of the cylinder body 2 is 7, the number of acid inlet holes facing the inner wall of the cylinder body 2 is 4, 2 acid inlet holes are correspondingly arranged in each independent compartment 24 located in the middle of the cylinder body 2, 1 acid inlet hole is correspondingly arranged in each independent compartment 24 located at the edge of the cylinder body 2, the diameter of the acid inlet holes is 16 mm, and the height of the partition rib plates 25 is 600 mm.

[0037] As Figure 1 shown, a bottom exhaust port 10 is provided on the lower cone body 3, and a middle exhaust port 11 is provided on the cylinder body 2. The bottom exhaust port 10 and the middle exhaust port 11 are both communicated with the top exhaust port 17.

[0038] Specifically, the bottom exhaust port 10 and the middle exhaust port 11 are connected by a gas communication pipe 13. The gas communication pipe 13 is communicated with the top exhaust port 17 through an upper air inlet 12. A valve 14 is provided between the bottom exhaust port 10 and the middle exhaust port 11. The bottom exhaust port 10 is located on the lower cone body 3 below the limestone support grid 4. The upper exhaust port is located at the top of the cylinder body 2, and the middle exhaust port 11 is located on the cylinder body 2 above the hydrochloric acid inlet pipe 5. The opening degree of the valve 14 between the bottom exhaust port 10 and the middle exhaust port 11 of the gas communication pipe 13 is adjusted to adjust the rising carbon dioxide gas volume to ensure that there is no foam on the surface of the lime stone layer in the reactor.

[0039] As Figure 4As shown in the figure, a baffle 6 is provided above the hydrochloric acid inlet pipe 5. Preferably, the cross-section of the baffle 6 is an inverted V shape. The center line of the baffle 6 and the axis of the hydrochloric acid inlet pipe 5 are in the same vertical plane. The width of the bottom of the baffle 6 is 2 to 5 times the diameter of the hydrochloric acid inlet pipe 5. In this embodiment, the diameter of the hydrochloric acid inlet pipe 5 is DN80, and the width of the bottom of the baffle 6 is 320 mm. The inverted V-shaped baffle 6, on the one hand, is used to protect the hydrochloric acid inlet pipe 5 from the pressure of limestone, and on the other hand, it ensures that the acid liquid ejected from the acid inlet hole directly enters the independent compartment 24 of the inlet pipe support grid 7 below the hydrochloric acid inlet pipe 5. During the interaction with the rising carbon dioxide gas, the acid liquid is quickly evenly distributed across the cross-section of the reactor. Without the inverted V-shaped baffle, the acid liquid of the hydrochloric acid inlet pipe is directly sprayed onto the filled limestone to form a short circuit and directly flows down along the partition rib plate of the inlet pipe support grid. The inverted V-shaped baffle structure forms a free space around the inlet pipe, expanding the radiation area of the acid liquid. Therefore, it can ensure that the acid liquid is horizontally sprayed into the independent compartment.

[0040] The working principle of the present invention is as follows: The limestone raw material is fed through the limestone feed inlet and fills the inside of the cylinder body 2 of the reactor. Hydrochloric acid is continuously introduced through the acid inlet pipe. During the process of flowing downward through the voids of the limestone packing layer, the hydrochloric acid reacts completely with the limestone. The hydrochloric acid concentration is high in the inlet pipe support grid 7 below the hydrochloric acid inlet pipe 5, and the reaction rate is fast. A large amount of carbon dioxide gas generated by the reaction flows upward, in a pulsed flow pattern, forming a pulsed flow reaction zone, realizing the uniform distribution of the acid liquid across the cross-section of this reaction zone. Most of the hydrochloric acid reacts with the limestone in this area; the hydrochloric acid concentration decreases in the area below the inlet pipe support grid 7, and the amount of carbon dioxide gas generated is small. The gas and liquid move downward in the same direction in the limestone packing layer. The liquid phase fluid flows in a liquid film shape on the surface of the particles, and the interaction between the gas and liquid phases is weak, in a trickle flow pattern, forming a trickle flow reaction zone, continuing to ensure the full reaction of hydrochloric acid and limestone. In the area above the inlet pipe support grid 7, the carbon dioxide comes into full contact with the limestone layer, playing a defoaming role, which is the defoaming zone. The generated calcium chloride solution, sediment, and acid-insoluble substances are discharged from the calcium chloride solution outlet 15, and the limestone consumed by the reaction falls from the limestone feed inlet for replenishment.

[0041] Through the above technical solution, a part of the carbon dioxide gas generated by the reaction in the pulse flow reaction zone flows upward in the cylinder body 2, contacts the limestone packing layer above the hydrochloric acid inlet pipe 5 sufficiently to remove mist and acid mist, and then is discharged through the upper exhaust port at the top. At the same time, it is shunted through the middle exhaust port 11. Another part of the carbon dioxide gas flows downward with the generated calcium chloride solution and is discharged through the lower exhaust port installed at the lower cone, reducing the upward speed of carbon dioxide in the cylinder body 2. The flow rate is related to the flow rate and cross-sectional area. The total flow rate is dispersed to multiple exhaust ports, and within the reactor cylinder body, the upward speed of carbon dioxide will decrease. Therefore, the phenomenon of serious entrainment of reaction tail gas mist caused by reactor foaming can be effectively controlled. The production intensity of the reactor is high, and the output per unit cross-sectional area is large.

[0042] A further solution of the present invention is that, as Figure 1 shown, the lower cone 3 is an inverted eccentric cone (the eccentric cone is an oblique cone in mathematical terms). Specifically, the calcium chloride solution outlet 15 is arranged at the lowest point of the lower cone 3 (i.e., the vertex of the oblique cone). The top surface of the lower cone 3 is the bottom surface of the oblique cone. By drawing a connection line between the vertex of the oblique cone and the edge of its bottom surface, it can be found that the length of the connection line takes the maximum and minimum values at two points respectively. A flushing liquid port 18 is arranged at the maximum value of the connection line from the calcium chloride solution outlet 15 to the top surface of the lower cone 3, and a bottom exhaust port 10 is arranged at the minimum value of the connection line from the calcium chloride solution outlet 15 to the top surface of the lower cone 3. By adopting the above solution, sediment, acid-insoluble substances and the calcium chloride solution flow down along the inner wall of the eccentric cone. Less sediment and acid-insoluble substances will adhere to the surface with a smaller slope, and there will be basically no residue on the surface with a larger slope. Therefore, arranging the flushing liquid port 18 at this position can clean the residues on the surface with a smaller slope to the greatest extent, and the bottom exhaust port 10 is arranged at the position from the calcium chloride solution outlet 15 to the maximum slope, which is convenient for carbon dioxide gas to be discharged from here.

[0043] The distance between the grid plates of the limestone support grid 4 is 12 mm to 30 mm. In this embodiment, the distance is 20 mm.

[0044] The bottom of the limestone support grid 4 is supported by support rib plates 26, and the discharge pipe 8 is arranged at the center of the limestone support grid 4. Specifically, as Figure 1 shown, a discharge port is arranged at the center of the limestone support grid 4. The shape of this discharge port is not limited. Preferably, it is a round port or a square port. In this embodiment, it is a 350 mm × 350 mm square discharge port. The discharge pipe 8 is installed directly below the discharge port at the center of the support grid. A discharge valve assembly 9 is arranged between the discharge port and the discharge pipe 8.

[0045] Specifically, the opening and closing of the discharge pipe 8 are controlled by the discharge valve assembly 9, and the discharge valve assembly 9 is installed in the discharge valve port 20, as Figure 5 、 Figure 6As shown in the figure, the discharge valve assembly 9 includes a hydraulic cylinder 27, a valve stem 28, a slideway 29, and a valve plate 30. The valve plate 30 is arranged between the limestone support grid 4 and the discharge pipe 8. The slideway 29 is arranged on the support rib plate 26. One end of the valve plate 30 is connected to the valve stem 28, and the valve plate 30 is slidably connected to the slideway 29. The hydraulic cylinder 27 drives the valve stem 28 to move, thereby driving the valve plate 30 to move along the slideway 29.

[0046] There is a gap between the upper edge of the valve plate 30 and the lower edge of the limestone support grid 4, and this gap is 5 mm to 20 mm. In this embodiment, this gap is 20 mm.

[0047] When the above embodiment is used for actual operation, limestone is continuously added into the cylinder body 2 of the reactor from the limestone feed inlet. When the reactor is initially charged, first add limestone with a relatively uniform particle size of 20 - 50 mm of limestone, and the optimal limestone particle size is 20 - 35 mm, to form a layer of limestone packing layer with relatively uniform void characteristics above the limestone support grid 4, and the height of this packing layer > 300 mm. After forming a uniform packing layer, the raw material limestone with a particle size < 100 mm can be added. 31% hydrochloric acid continuously enters the reactor through the hydrochloric acid inlet pipe 5, and the acid inlet amount is 16 m 3 / hr. The hydrochloric acid inlet pipe support grid 7 is installed below the hydrochloric acid inlet pipe 5 to divide the area below the hydrochloric acid inlet pipe 5 into independent compartments 24. The hydrochloric acid concentration in this area is high and the reaction rate is fast. A large amount of CO 2 gas flows upward and strongly acts with the downward flowing acid solution, being a pulsed flow pattern, realizing the uniform distribution of the acid solution in the cross-section of the reactor. Most of the hydrochloric acid reacts with the limestone in this area. In the area below the hydrochloric acid inlet pipe support grid 7, the hydrochloric acid concentration is low, and the amount of CO 2 generated is small. The gas and liquid flow downward in the same direction in the limestone packing bed. The liquid phase fluid flows in a liquid film shape on the surface of the particles, and the interaction between the gas and liquid phases is weak, being a trickle flow pattern, ensuring the full reaction of hydrochloric acid and limestone. When the reaction liquid flows to the limestone packing layer with relatively uniform porosity above the limestone support grid 4, it has basically reacted completely. The limestone in this packing layer basically does not participate in the reaction, and the filling characteristics of the packing layer are stable, which is beneficial to the stable operation of the reactor. The generated calcium chloride solution entraining the sediment and acid-insoluble substances in the limestone flows into the eccentric lower cone 3 below the limestone support grid 4 and is continuously discharged from the calcium chloride solution outlet 15 provided at the lowest part of the lower cone 3. During normal operation, it is observed through the sight glass port 23 installed on the upper cone of the reactor, and the opening degree of the valve 14 of the gas connection pipe 13 is adjusted to adjust the rising CO 2 gas volume to ensure that there are no bubbles on the surface of the limestone material layer in the reactor. The hydrochloric acid reaction conversion rate of the present invention is high, and the conversion rates of the raw material limestone and hydrochloric acid are close to 100%. The pH of the calcium chloride solution at the reactor outlet > 4.0.

[0048] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, 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 embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

Claims

1. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone, characterized in that: The invention comprises an upper cone (1), a cylinder (2) and a lower cone (3) which are arranged in sequence from top to bottom, wherein the top of the upper cone (1) is provided with a limestone feed port (16) and a top exhaust port (17), the bottom of the lower cone (3) is provided with a calcium chloride solution outlet (15), the top of the upper cone (1) is also provided with a pressure sensor (22) and a sight glass port (23), and a manhole (21) is provided below the cylinder (2); A limestone support grid (4) is provided between the cylinder (2) and the lower cone (3), and an openable and closable discharge pipe (8) is provided at the bottom of the limestone support grid (4); Two or more groups of hydrochloric acid inlet pipes (5) arranged horizontally are arranged side by side in the cylinder (2), and a plurality of acid inlet holes are horizontally distributed on both sides of the hydrochloric acid inlet pipe (5). An acid inlet pipe support grid (7) is arranged below the hydrochloric acid inlet pipe (5), and the acid inlet pipe support grid (7) divides the area below the acid inlet pipe into a plurality of independent compartments (24); The lower cone (3) is provided with a bottom exhaust port (10), the top of the cylinder (2) is provided with an upper air inlet (12), the upper part of the cylinder (2) is provided with a middle exhaust port (11) between the hydrochloric acid inlet pipe (5) and the upper air inlet (12), the bottom exhaust port (10), the middle exhaust port (11) and the upper air inlet (12) are connected via a gas connecting pipe (13), and a valve (14) is provided between the bottom exhaust port (10) and the middle exhaust port (11).

2. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to claim 1, characterized in that: The middle exhaust port (11) is arranged between the hydrochloric acid inlet pipe (5) and the upper air inlet (12) and close to the upper air inlet (12).

3. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to claim 2, characterized in that: The hydrochloric acid inlet pipe (5) is arranged in the upper middle part of the cylinder (2).

4. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to claim 3, characterized in that: A baffle (6) is arranged above the hydrochloric acid inlet pipe (5), the cross section of the baffle (6) is an inverted V-shape, the center line of the baffle (6) and the axis of the hydrochloric acid inlet pipe (5) are in the same vertical plane, and the width of the bottom of the baffle (6) is 2 to 5 times the diameter of the hydrochloric acid inlet pipe (5).

5. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to claim 1, characterized in that: The acid inlet pipe support grid (7) is formed into a plurality of independent compartments (24) by means of a partition rib plate (25), and the independent compartments (24) close to the inner wall of the cylinder (2) are separated from the inner wall of the cylinder (2) by means of the partition rib plate (25).

6. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to claim 5, characterized in that: The hydrochloric acid inlet pipes (5) are provided in two groups, and the two groups of hydrochloric acid inlet pipes (5) are symmetrically distributed along the diameter of the cross section of the cylinder (2).

7. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to any one of claims 1 to 6, characterized in that: The lower cone (3) is an inverted eccentric cone. The calcium chloride solution outlet (15) is arranged at the lowest point of the lower cone (3). A flushing liquid outlet (18) is arranged at the maximum value of a line connecting the calcium chloride solution outlet (15) and the top surface of the lower cone (3). The bottom exhaust port (10) is arranged at the minimum value of a line connecting the calcium chloride solution outlet (15) and the top surface of the lower cone (3).

8. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to claim 6, characterized in that: Each independent compartment (24) located in the middle of the cylinder (2) between the two groups of hydrochloric acid inlet pipes (5) is provided with 2 to 8 acid inlet holes, and each independent compartment (24) located at the edge of the cylinder (2) of each group of hydrochloric acid inlet pipes (5) is provided with 1 to 4 acid inlet holes. The diameter of the acid inlet holes is 12 mm to 20 mm, and the height of the partition rib plate (25) is 400 mm to 800 mm.

9. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to claim 7, characterized in that: The spacing between the grid plates of the limestone support grid (4) is 12 mm to 30 mm. The bottom of the limestone support grid (4) is supported by a supporting rib plate (26). A discharge hole is opened in the center of the limestone support grid (4) and connected to a discharge pipe (8).

10. A trickle bed reactor for continuously producing calcium chloride solution by reacting hydrochloric acid and limestone according to claim 9, characterized in that: The discharge pipe (8) is controlled to open and close by a discharge valve assembly (9). The discharge valve assembly (9) comprises a hydraulic cylinder (27), a valve stem (28), a slideway (29) and a valve plate (30). The valve plate (30) is arranged between the limestone support grid (4) and the discharge pipe (8). The slideway (29) is arranged on the support rib plate (26). One end of the valve plate (30) is connected to the valve stem (28). The valve plate (30) is slidably connected to the slideway (29). A gap is left between the upper edge of the valve plate (30) and the lower edge of the limestone support grid (4). The gap is 5 mm to 20 mm.

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