Vertical concentrated sulfuric acid circulating tank, concentrated sulfuric acid dry absorption production system and dry absorption production process

Abstract

The invention discloses a vertical concentrated sulfuric acid circulating tank, a concentrated sulfuric acid dry absorption production system and a dry absorption production process, and belongs to the technical field of concentrated sulfuric acid production. The vertical concentrated sulfuric acid circulating tank comprises a tank body and a cover plate, the tank body is sealed by the cover plate, a slope layer is arranged at the bottom in the tank body, an arc-shaped cofferdam is arranged on the upper side of the slope layer, an inner cavity of the tank body is divided into a first cavity and a second cavity by the arc-shaped cofferdam, and a horizontal hole communicated with the first cavity and the second cavity is formed in the bottom of the arc-shaped cofferdam. According to the invention, a large-volume and improved absorption circulating tank is used for replacing a primary absorption circulating tank and a secondary absorption circulating tank, and on the basis, the technological process of an acid-making dry absorption section is optimized, so that the occupied area of equipment, the length of a pipeline and the number of required pipe fittings and instruments are reduced, and the cost is reduced; the acid mixing process is simplified, and the labor intensity is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of concentrated sulfuric acid preparation, and particularly relates to a vertical concentrated sulfuric acid circulation tank, a concentrated sulfuric acid drying and absorption production system, and a drying and absorption production process. Background Art

[0002] The drying and absorption section is an indispensable part of dry-process sulfuric acid production. The concentrated sulfuric acid circulation tank is an important device in this section. Its function is to receive the concentrated sulfuric acid flowing out from the bottom of the absorption tower, and then pump it into the absorption tower through a circulation pump to form an acid circulation. The stability of the acid concentration in the circulation tank is controlled by the acid transfer between different circulation tanks and the addition of water. Currently, the "two-stage conversion and two-stage absorption" process is mostly used in industrial sulfuric acid production. Its advantages are as follows: 1. The conversion reaction speed is fast, and the final conversion rate is high; 2. It can handle gases with a relatively high SO 2 content; 3. It can reduce the content of SO 2 in the tail gas. The "two-stage conversion and two-stage absorption" process generally includes two sets of absorption towers and circulation tanks, which are respectively used to treat the gases after the first-stage conversion and the second-stage conversion. There are two types of concentrated sulfuric acid circulation tanks: vertical and horizontal. The former is used in small-scale sulfuric acid plants and occupies a relatively small area; the latter is used in large-scale sulfuric acid plants, occupies a large area, and has a relatively high processing difficulty.

[0003] The existing drying and absorption production process has the following disadvantages:

[0004] 1. Equipping the two absorption towers with corresponding absorption circulation tanks respectively will increase the floor area of the equipment, the length of the pipelines required for the process, and the number of pipe fittings and instruments, thus increasing the investment cost;

[0005] 2. During the operation of the device, the operators need to observe the operating status of different circulation tanks respectively, and pay attention to the acid transfer between the drying circulation tank, the first absorption circulation tank, and the second absorption circulation tank. The labor intensity is high and it is easy to be negligent.

[0006] In addition, when the existing concentrated sulfuric acid circulation tank is feeding acid, it is easy to impact the liquid outlet casing, and eddy currents are extremely likely to occur in the tank, resulting in uneven acid mixing; when discharging acid, there is easily acid residue in the vertical acid tank, which is not conducive to the maintenance of the operators. Summary of the Invention

[0007] In order to solve the technical problems that when the existing concentrated sulfuric acid circulation tank is feeding acid, it is easy to impact the liquid outlet casing and eddy currents are extremely likely to occur in the tank, resulting in uneven acid mixing, and when discharging acid, there is easily acid residue in the vertical acid tank, which is not conducive to the maintenance of the operators, the present invention provides a vertical concentrated sulfuric acid circulation tank.

[0008] Therefore, the technical solution adopted by the present invention is:

[0009] A vertical concentrated sulfuric acid circulation tank, comprising a tank body and a cover plate. The tank body is sealed by the cover plate. A slope layer is arranged at the bottom inside the tank body. An arc-shaped cofferdam is arranged above the slope layer. The height of the arc-shaped cofferdam is lower than the height of the inner cavity of the tank body, and the inner cavity of the tank body is divided into a first cavity and a second cavity. The volume of the second cavity is smaller than that of the first cavity and its bottom surface is higher than that of the first cavity. The open end of the arc-shaped cofferdam faces the first cavity and a horizontal hole communicating the first cavity and the second cavity is arranged at its bottom; on the cover plate above the first cavity, there are arranged a mother acid port, an exhaust port, a temperature measuring port, a liquid level gauge interface, a manhole and two circulating acid pump interfaces; on the cover plate above the second cavity, there are arranged an instrument return acid port, a water adding port, a first absorption circulating tank return acid port, a second absorption circulating tank return acid port and a dilute acid inlet port; on the side wall of the tank body, there are arranged an overflow port, an acid discharging port and an acid cross-flow port. The overflow port and the acid discharging port are communicated with the first cavity, and the acid cross-flow port is communicated with the second cavity.

[0010] Further, the tank body is made of a steel shell lined with an acid-resistant layer. The acid-resistant layer includes an asbestos board, an acid-resistant cement mortar and acid-resistant bricks which are connected in sequence from outside to inside; the top cover is made of a steel plate, and the lower surface of the steel plate is coated with 3 to 5 layers of epoxy-phenolic resin paint for corrosion prevention.

[0011] Further, the arc-shaped cofferdam is built with acid-resistant bricks, and an I-shaped stepped acid-resistant brick wall for reinforcement is arranged at the arc center part.

[0012] Further, the slope layer is built with acid-resistant bricks, and the slope is 2 to 5°. The acid discharging port is located at the lowest elevation of the slope layer and its bottom elevation is the same as the lowest point elevation of the slope layer. There are multiple horizontal holes which are evenly distributed at the lower part of the cofferdam and the bottom surface elevation of the holes is located on the intersection line of the slope layer and the cofferdam.

[0013] To solve the technical problems existing in the existing drying and absorption process, such as large floor area of equipment, long process pipelines, large number of pipe fittings, high labor intensity of operators and easy negligence, the present invention provides a concentrated sulfuric acid drying and absorption production system and a drying and absorption production process. For this purpose, the technical solution adopted by the present invention is:

[0014] A concentrated sulfuric acid drying and absorption production system, characterized in that it includes a drying tower, a first absorption tower, a second absorption tower, a drying circulating tank, a drying acid cooler, a first absorption acid cooler, a second absorption acid cooler, a drying tank acid circulating pump, a circulating tank acid circulating pump A, a circulating tank acid circulating pump B and any one of the above vertical concentrated sulfuric acid circulation tanks; the circulating tank acid circulating pump A and the circulating tank acid circulating pump B are respectively installed on the two circulating acid pump interfaces of the vertical concentrated sulfuric acid circulation tank;

[0015] The drying circulation tank is connected to the vertical concentrated sulfuric acid circulation tank through acid transfer pipes A and B. Acid transfer regulating valves A and B are respectively installed on acid transfer pipes A and B. One end of acid transfer pipe A is connected to the outlet pipeline of the acid circulation pump in the drying tank, and the other end is connected to the acid transfer port of the vertical concentrated sulfuric acid circulation tank. One end of acid transfer pipe B is connected to the outlet pipeline of acid circulation pump A or acid circulation pump B in the circulation tank, and the other end is connected to the acid transfer port of the drying circulation tank.

[0016] The acid discharge port at the bottom of the drying tower is connected to the acid inlet of the drying circulation tank through a pipeline. The acid circulation pump in the drying tank is installed in the acid outlet at the top of the drying circulation tank, and the outlet of the acid circulation pump in the drying tank is connected to the acid inlet of the drying acid cooler through a pipeline; the acid outlet of the drying acid cooler is connected to the drying tower through a pipeline.

[0017] The acid discharge ports at the bottoms of the first absorption tower and the second absorption tower are respectively connected to the acid return ports of the first absorption circulation tank and the second absorption circulation tank of the vertical concentrated sulfuric acid circulation tank through pipelines. The outlets of acid circulation pump A and acid circulation pump B in the circulation tank are respectively connected to the acid inlets of the first absorption acid cooler and the second absorption acid cooler through pipelines; the acid outlets of the first absorption acid cooler and the second absorption acid cooler are respectively connected to the first absorption tower and the second absorption tower through pipelines.

[0018] A branch pipe connecting to the finished acid tank is provided on the outlet pipeline of the acid circulation pump in the drying tank, and a 93% finished acid outlet pipeline valve is installed on the branch pipe; branch pipes connecting to the finished acid tank are respectively provided on the outlet pipelines of acid circulation pump A and acid circulation pump B in the circulation tank, and 98% finished acid outlet pipeline valves are installed on the branch pipes.

[0019] Furthermore, the overflow port and the acid discharging port of the vertical concentrated sulfuric acid circulation tank are respectively connected to the underground tank through pipelines.

[0020] Furthermore, the outlet pipelines of acid circulation pump A and acid circulation pump B in the circulation tank are both connected to a small-diameter branch pipe, and an acid concentration meter is installed on the small-diameter branch pipe for real-time monitoring of the acid concentration.

[0021] Furthermore, the outlet pipeline of the acid circulation pump in the drying tank is connected to a small-diameter branch pipe, and an acid concentration meter is installed on the small-diameter branch pipe for real-time monitoring of the acid concentration.

[0022] A concentrated sulfuric acid drying and absorption production process uses the above-mentioned concentrated sulfuric acid drying and absorption production system, including the following steps:

[0023] (1) The 98.4 - 98.6% concentrated sulfuric acid from the first absorption tower and the second absorption tower respectively enters the second cavity of the vertical concentrated sulfuric acid circulation tank through the acid return ports of the first absorption circulation tank and the second absorption circulation tank. The 98.5% concentrated sulfuric acid entering the second cavity flows along the slope layer through the horizontal holes at the bottom of the cofferdam to the first cavity and is mixed evenly.

[0024] (2) Start the acid circulation pump of the drying tank, adjust the acid transfer amount through the acid transfer regulating valve A, adjust the amount of dilute acid added from the dilute acid inlet, and adjust the amount of makeup water added from the water inlet to make the sulfuric acid concentration in the absorption circulation tank 98%;

[0025] (3) The 98% concentrated sulfuric acid in the vertical concentrated sulfuric acid circulation tank is sent to the first absorption acid cooler and the second absorption acid cooler respectively through the circulation tank acid circulation pump A and the circulation tank acid circulation pump B, and after being cooled by the acid cooler, it enters the first absorption tower and the second absorption tower respectively to absorb SO 3 in the converted furnace gas. After the concentration increases to 98.5%, it returns to the vertical concentrated sulfuric acid circulation tank to complete a circulation cycle;

[0026] (4) Close the valve of the 93% finished acid outlet pipeline, open the valve of the 98% finished acid outlet pipeline, and produce 98% concentrated sulfuric acid.

[0027] A concentrated sulfuric acid drying and absorption production process uses the above-mentioned concentrated sulfuric acid drying and absorption production system, including the following steps:

[0028] (1) The 92.4 - 92.6% concentrated sulfuric acid from the drying tower enters the drying circulation tank; the approximately 98.5% concentrated sulfuric acid from the first absorption tower and the second absorption tower enters the second cavity of the vertical concentrated sulfuric acid circulation tank through the first absorption circulation tank acid return port and the second absorption circulation tank acid return port respectively. The 98.5% concentrated sulfuric acid entering the second cavity flows along the slope layer through the horizontal holes at the bottom of the cofferdam to the first cavity and is mixed evenly;

[0029] (2) Start the circulation tank acid circulation pump A or the circulation tank acid circulation pump B, adjust the acid transfer amount through the acid transfer regulating valve B to make the sulfuric acid concentration in the drying circulation tank 93%;

[0030] (3) The 93% concentrated sulfuric acid in the drying circulation tank is sent to the drying acid cooler through the 93% acid circulation pump at the top of the drying circulation tank, and after being cooled by the acid cooler, it is sent to the drying tower to absorb H 2 O in the flue gas. After the concentration is reduced to 92.5%, it returns to the drying circulation tank to complete a circulation cycle;

[0031] (4) Close the valve of the 98% finished acid outlet pipeline, open the valve of the 93% finished acid outlet pipeline, and produce 93% concentrated sulfuric acid.

[0032] The beneficial effects of the present invention:

[0033] 1. The vertical concentrated sulfuric acid circulation tank guides the flow of concentrated sulfuric acid through the setting of an arc-shaped cofferdam and a slope layer, reduces the generation of eddy currents, makes the mixed acid uniform, improves the stability of the device operation, and is conducive to draining the concentrated acid in the tank during maintenance.

[0034] 2. Replaced the first absorption circulation tank and the second absorption circulation tank with a large-capacity and improved absorption circulation tank, and on this basis, optimized the technological process of the drying and absorption section of sulfuric acid production, reducing the floor area of equipment, the length of pipelines, and the number of required pipe fittings and instruments, thus reducing costs; simplified the acid circulation process and lowered the labor intensity. Brief Description of the Drawings

[0035] Figure 1 It is a schematic structural diagram of the vertical concentrated sulfuric acid circulation tank of the present invention.

[0036] Figure 2 It is a schematic diagram of the internal structure of the tank body of the vertical concentrated sulfuric acid circulation tank of the present invention.

[0037] Figure 3 It is a schematic structural diagram of the top cover of the vertical concentrated sulfuric acid circulation tank of the present invention.

[0038] Figure 4 It is a schematic diagram of the process structure of the concentrated sulfuric acid drying and absorption production system of the present invention.

[0039] Description of the Reference Numerals in the Drawings:

[0040] 1 - Ramp layer; 2 - Acid discharge port; 3 - Acid-resistant ceramic tiles; 4 - Overflow port; 5 - Top cover; 6 - Manhole; 7 - I-beam; 8 - Circulation pump connection port; 9 - Acid return pipe; 10 - Acid circulation port; 11 - Arc-shaped cofferdam; 12 - Horizontal opening; 100 - Absorption circulation tank;

[0041] 51 - Mother acid port; 52 - Exhaust port; 53 - Temperature measurement port; 54 - Magnetic flap level gauge connection port; 55 - Manhole; 56 - I-beam; 57 - Circulation pump connection port; 58 - Instrument acid return port; 59 - Water addition port; 510 - Acid return port of the first absorption circulation tank; 511 - Acid return port of the second absorption circulation tank; 512 - Dilute acid inlet port;

[0042] 31 - Acid circulation pump for the drying tank; 321 - Acid circulation pump A for the circulation tank; 322 - Acid circulation pump B for the circulation tank; 33 - 93% acid concentration detector; 34 - 98% acid concentration detector; 35 - Valve for the 93% finished acid outlet pipeline; 36 - Valve for the 98% finished acid outlet pipeline; 37 - Acid circulation regulating valve A; 38 - Acid circulation regulating valve B; 301 - Drying tower; 302 - First absorption tower; 303 - Second absorption tower; 304 - Drying circulation tank; 305 - Drying acid cooler; 306 - First absorption acid cooler; 307 - Second absorption acid cooler. Detailed Embodiments

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings and a preferred embodiment.

[0044] Example 1

[0045] This embodiment provides a vertical concentrated sulfuric acid circulation tank 100, which includes a tank body and a top cover 5. A slope layer 1 is arranged at the bottom inside the tank body, and an arc-shaped cofferdam 11 is arranged on the upper side of the slope layer 1. The arc-shaped cofferdam 11 divides the inner cavity of the tank body into a first cavity and a second cavity, and the first cavity and the second cavity are communicated through a horizontal hole 12 at the bottom of the arc-shaped cofferdam 11. The top cover 5 is provided with a mother acid inlet 51, an exhaust port 52, a temperature measuring port 53, a magnetic flap level gauge interface 54, a manhole 55, a circulating acid pump interface 57, an instrument return acid port 58, a water inlet 59, a first absorption circulating tank return acid port 510, a second absorption circulating tank return acid port 511 and a dilute acid inlet 512; an overflow port 4 is arranged at the upper part of the side wall of the circulating tank, a series acid port 10 is arranged in the middle, and a drain port 2 is arranged at the bottom; the mother acid inlet 51, the exhaust port 52, the temperature measuring port 53, the magnetic flap level gauge interface 54, the manhole 55 and the circulating acid pump interface 57 are arranged at the top of the first cavity; the instrument return acid port 58, the water inlet 59, the first absorption circulating tank return acid port 510, the second absorption circulating tank return acid port 511 and the dilute acid inlet 512 are arranged at the top of the second cavity; the series acid port 10 is arranged on the side wall of the second cavity and is communicated with the second cavity, and the overflow port 4 and the series acid port 10 are arranged on the side wall of the first cavity and are communicated with the first cavity.

[0046] The tank body is composed of a steel shell and a lining layer. The lining layer includes a 3-mm-thick asbestos board, a 5-mm-thick acid-resistant mortar and a layer of acid-resistant bricks 3 connected in sequence from outside to inside. The top cover 5 is sealed. Above the top cover 2, multiple symmetrically distributed I-beams 7 are welded to play a strengthening role. Small holes are opened at the bottom sides of the leftmost and rightmost I-beams to prevent rainwater accumulation. The lower surface of the top cover is painted with five layers of epoxy-phenolic resin paint for corrosion protection.

[0047] The mother acid inlet 51 is used to supplement fresh concentrated sulfuric acid. The manhole 55 is used for maintenance. The temperature measuring port 53 is used to install a thermometer to measure the temperature of the concentrated sulfuric acid through the thermometer. The magnetic flap level gauge interface 54 is used to install a magnetic flap level gauge to measure the liquid level of the concentrated sulfuric acid in the tank body through the level gauge. Two circulating acid pump interfaces 57 are symmetrically arranged in the middle of the top cover 5 of the circulating tank and are respectively connected to a concentrated sulfuric acid circulating pump, namely the circulating tank acid circulating pump A321 and the circulating tank acid circulating pump B322.

[0048] The arc-shaped cofferdam 11 is made of acid-resistant bricks, and its height is about 3 / 4 of the height of the tank body. A stepped acid-resistant brick wall is arranged near the inner side wall of the first cavity at the center of the cofferdam for reinforcement. Four square horizontal holes 12 are evenly opened on the lower side of the arc-shaped cofferdam 11 for the flow of acid liquid.

[0049] The inclined layer 1 is made of acid-resistant bricks and acid-resistant concrete, and inclines from the second cavity to the first cavity with a slope of about 2°. The acid discharge port 2 is located at the lowest elevation of the inclined layer 1 and its bottom elevation is the same as the lowest elevation of the inclined layer, so that the acid liquid can be discharged completely. The lowest elevation of the 4 horizontal holes 12 is located on the intersection line of the inclined layer 1 and the cofferdam 11, so that the acid in the second cavity can be completely discharged into the first cavity without remaining in the second cavity.

[0050] Embodiment 2

[0051] This embodiment provides a concentrated sulfuric acid drying and absorption production system, including a drying tower 301, a first absorption tower 302, a second absorption tower 303, a drying circulation tank 304, a drying acid cooler 305, a first absorption acid cooler 306, a second absorption acid cooler 307, a drying tank acid circulation pump 31, a circulation tank acid circulation pump A 321, a circulation tank acid circulation pump B 322, and the vertical concentrated sulfuric acid circulation tank 100 of Embodiment 1;

[0052] The drying circulation tank 304 is connected to the vertical concentrated sulfuric acid circulation tank through an acid transfer pipe A and an acid transfer pipe B. An acid transfer regulating valve A 37 and an acid transfer regulating valve B 38 are respectively provided on the acid transfer pipe A and the acid transfer pipe B. One end of the acid transfer pipe A is connected to the outlet pipeline of the drying tank acid circulation pump 31, and the other end is connected to the acid transfer port 10 of the vertical concentrated sulfuric acid circulation tank. One end of the acid transfer pipe B is connected to the outlet pipeline of the circulation tank acid circulation pump A 321 or the circulation tank acid circulation pump B 322, and the other end is connected to the acid transfer port of the drying circulation tank 304.

[0053] The acid discharge port at the bottom of the drying tower 301 is connected to the acid inlet of the drying circulation tank 304 through a pipeline. The drying tank acid circulation pump 31 is installed in the acid outlet at the top of the drying circulation tank 304, and the outlet of the drying tank acid circulation pump 31 is connected to the acid inlet of the drying acid cooler 305 through a pipeline; the acid outlet of the drying acid cooler 305 is connected to the drying tower 301 through a pipeline;

[0054] The acid discharge ports at the bottoms of the first absorption tower 302 and the second absorption tower 303 are respectively connected to the first absorption circulation tank acid return port 510 and the second absorption circulation tank acid return port 511 of the vertical concentrated sulfuric acid circulation tank through pipelines. The outlets of the circulation tank acid circulation pump A 321 and the circulation tank acid circulation pump B 322 are respectively connected to the acid inlets of the first absorption acid cooler 306 and the second absorption acid cooler 307 through pipelines; the acid outlets of the first absorption acid cooler 306 and the second absorption acid cooler 307 are respectively connected to the first absorption tower 302 and the second absorption tower 303 through pipelines;

[0055] A branch pipe connecting to the finished acid tank is provided on the outlet pipeline of the drying tank acid circulation pump 31, and a 93% finished acid outlet pipeline valve 35 is provided on the branch pipe; a branch pipe connecting to the finished acid tank is respectively provided on the outlet pipelines of the circulation tank acid circulation pump A 321 and the circulation tank acid circulation pump B 322, and a 98% finished acid outlet pipeline valve 36 is provided on the branch pipe.

[0056] The outlet pipelines of the acid circulation pump A321 and the acid circulation pump B322 of the circulation tank are both connected to a branch pipe with a small diameter. An acid concentration meter is installed on the branch pipe for real-time monitoring of the acid concentration. The sulfuric acid flowing through the acid concentration meter flows back into the absorption circulation tank 100 through the instrument acid return port 58 on the top of the tank.

[0057] The outlet pipelines of the acid circulation pump A321 and the acid circulation pump B322 of the circulation tank are both connected to a branch pipe with a small diameter. An acid concentration meter is installed on the branch pipe for real-time monitoring of the acid concentration. The sulfuric acid flowing through the acid concentration meter flows back into the absorption circulation tank 100 through the instrument acid return port 58 on the top of the tank.

[0058] The top exhaust port 52 of the vertical concentrated sulfuric acid circulation tank 100 is connected to the flue gas inlet pipe of the drying tower through a pipeline; the SO 2 、SO 3 contained in the circulating acid liquid is discharged through the exhaust port 52 and incorporated into the flue gas at the outlet of the purification section and enters the drying tower together, avoiding air pollution and safety problems caused by gas discharge.

[0059] The outlet pipelines of the acid circulation pump A321 and the acid circulation pump B322 of the circulation tank are both connected to a branch pipe with a small diameter. An acid concentration meter is installed on the branch pipe for real-time monitoring of the acid concentration. The sulfuric acid flowing through the acid concentration meter flows back into the absorption circulation tank 100 through the instrument acid return port 58 on the top of the tank. The outlet pipeline of the drying tank acid circulation pump 31 is connected to a branch pipe with a small diameter. An acid concentration meter is installed on the branch pipe for real-time monitoring of the acid concentration. The concentrated sulfuric acid flowing through the acid concentration meter flows back into the drying circulation tank 304.

[0060] The water inlet 59 at the top of the vertical concentrated sulfuric acid circulation tank 100 is connected to the production water pipe; the dilute acid inlet 512 at the top of the vertical concentrated sulfuric acid circulation tank 100 is connected to the dilute sulfuric acid pipeline from the purification section.

[0061] The overflow port 4 and the acid discharge port 2 of the vertical concentrated sulfuric acid circulation tank 100 are respectively connected to the underground tank through pipelines. When the liquid level of the concentrated sulfuric acid in the absorption circulation tank 100 reaches the overflow port 4, the excess concentrated sulfuric acid will automatically overflow to the underground tank through the overflow port 4 to prevent accidents such as overflowing of the tank. When it is necessary to repair the absorption circulation tank 100, all the liquid in the tank flows into the underground tank through the acid discharge port 2, and the maintenance personnel enter the tank through the manhole for repair.

[0062] Example 3

[0063] This example provides a process method for concentrated sulfuric acid drying and absorption production using the concentrated sulfuric acid drying and absorption production system of Example 2, including the following steps:

[0064] (1) Approximately 98.5% concentrated sulfuric acid from the first absorption tower 302 and the second absorption tower 303 enters the second cavity inside the tank through the acid return port 510 of the first absorption circulation tank and the acid return port 511 of the second absorption circulation tank respectively. The 98.5% concentrated sulfuric acid that enters the second cavity flows to the first cavity along the slope layer 1 through four horizontal holes 12 at the bottom of the cofferdam and is evenly mixed.

[0065] (2) Start the acid circulation pump 31 of the drying tank, adjust the acid transfer amount through the acid transfer regulating valve A37, adjust the amount of dilute acid added from the dilute acid inlet, and adjust the amount of makeup water added from the water inlet to make the sulfuric acid concentration in the absorption circulation tank 98%;

[0066] (3) The 98% concentrated sulfuric acid in the absorption circulation tank 100 is sent to the first absorption acid cooler 306 and the second absorption acid cooler 307 respectively through the acid circulation pump A321 and the acid circulation pump B322 of the circulation tank. After being cooled by the acid cooler, it enters the first absorption tower 302 and the second absorption tower 303 respectively to absorb SO 3 in the converted furnace gas. After the concentration increases to 98.5%, it returns to the absorption circulation tank 100, thus completing a circulation cycle;

[0067] (4) Close the valve of the 93% finished acid outlet pipeline and open the valve of the 98% finished acid outlet pipeline to produce 98% concentrated sulfuric acid.

[0068] Example 4:

[0069] This example provides a process method for concentrated sulfuric acid drying and absorption production using the concentrated sulfuric acid drying and absorption production system of Example 2, including the following steps:

[0070] (1) Approximately 92.5% concentrated sulfuric acid from the drying tower 301 enters the drying circulation tank 304; approximately 98.5% concentrated sulfuric acid from the first absorption tower 302 and the second absorption tower 303 enters the second cavity of the vertical concentrated sulfuric acid circulation tank 100 through the acid return port 510 of the first absorption circulation tank and the acid return port 511 of the second absorption circulation tank respectively. The 98.5% concentrated sulfuric acid that enters the second cavity flows to the first cavity along the slope layer 1 through the horizontal holes 12 at the bottom of the cofferdam and is evenly mixed;

[0071] (2) Start the acid circulation pump A321 of the circulation tank, adjust the acid transfer amount through the acid transfer regulating valve B38 to make the sulfuric acid concentration in the drying circulation tank 304 93%;

[0072] (3) The 93% concentrated sulfuric acid in the drying circulation tank 304 is sent to the drying acid cooler 305 through the 93% acid circulation pump 31 at the top of the drying circulation tank. After being cooled by the acid cooler, it is sent to the drying tower 301 to absorb H 2 O in the flue gas. After the concentration decreases to 92.5%, it returns to the drying circulation tank 304, thus completing a circulation cycle;

[0073] (4) Close the valve 36 of the 98% finished acid outlet pipeline and open the valve 35 of the 93% finished acid outlet pipeline to produce 93% concentrated sulfuric acid.

[0074] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also within the protection scope of the present invention.

Claims

1. A vertical concentrated sulfuric acid circulation tank, comprising a tank body and a cover plate (5), the tank body is sealed by the cover plate (5), characterized in that, a slope layer (1) is arranged at the bottom inside the tank body, an arc-shaped cofferdam (11) is arranged on the upper side of the slope layer (1), the height of the arc-shaped cofferdam (11) is lower than the height of the inner cavity of the tank body, and the inner cavity of the tank body is divided into a first cavity and a second cavity, the volume of the second cavity is smaller than that of the first cavity and the bottom surface is higher than that of the first cavity, the open end of the arc-shaped cofferdam (11) faces the first cavity and a horizontal hole (12) communicating the first cavity and the second cavity is arranged at its bottom; on the cover plate (5) above the first cavity, there are arranged a mother acid port (51), an exhaust port (52), a temperature measuring port (53), a liquid level gauge interface, a manhole (55) and two circulating acid pump interfaces (57); on the cover plate (5) above the second cavity, there are arranged an instrument return acid port (58), a water adding port (59), a first absorption circulating tank return acid port (510), a second absorption circulating tank return acid port (511) and a dilute acid inlet port (512); on the side wall of the tank body, there are arranged an overflow port (4), a acid discharging port (2) and an acid cross-connection port (10), the overflow port (4) and the acid discharging port (2) are communicated with the first cavity, and the acid cross-connection port (10) is communicated with the second cavity.

2. A vertical concentrated sulfuric acid circulation tank according to claim 1, characterized in that, the tank body is made of a steel shell lined with an acid-resistant layer, and the acid-resistant layer includes an asbestos board, an acid-resistant cement mortar and acid-resistant bricks which are connected in sequence from outside to inside; the top cover is made of a steel plate, and 3 to 5 coats of epoxy-phenolic resin paint are applied on the lower surface of the steel plate for anti-corrosion.

3. A vertical concentrated sulfuric acid circulation tank according to claim 1, characterized in that, the arc-shaped cofferdam (11) is built with acid-resistant bricks, and an I-shaped stepped acid-resistant brick wall for reinforcement is arranged at the arc center part.

4. A vertical concentrated sulfuric acid circulation tank according to claim 1, characterized in that, the slope layer (1) is built with acid-resistant bricks, the slope is 2 to 5°, the acid discharging port (2) is located at the lowest elevation of the slope layer (1) and the bottom elevation thereof is consistent with the lowest point elevation of the slope layer, there are a plurality of horizontal holes (12), which are uniformly distributed at the lower part of the cofferdam (11) and the bottom surface elevation of the holes is located on the intersection line of the slope layer (1) and the cofferdam (11).

5. A concentrated sulfuric acid drying and absorption production system, characterized in that, it includes a drying tower (301), a first absorption tower (302), a second absorption tower (303), a drying circulating tank (304), a drying acid cooler (305), a first absorption acid cooler (306), a second absorption acid cooler (307), a drying tank acid circulating pump (31), a circulating tank acid circulating pump A (321), a circulating tank acid circulating pump B (322) and the vertical concentrated sulfuric acid circulation tank (100) according to any one of claims 1 to 4; the circulating tank acid circulating pump A (321) and the circulating tank acid circulating pump B (322) are respectively installed on the two circulating acid pump interfaces (57) of the vertical concentrated sulfuric acid circulation tank; The drying circulation tank (304) is connected to the vertical concentrated sulfuric acid circulation tank through acid transfer pipes A and B. Acid transfer regulating valves A (37) and B (38) are respectively installed on acid transfer pipes A and B. One end of acid transfer pipe A is connected to the outlet pipeline of the acid circulation pump (31) of the drying tank, and the other end is connected to the acid transfer port (10) of the vertical concentrated sulfuric acid circulation tank. One end of acid transfer pipe B is connected to the outlet pipeline of the acid circulation pump A (321) or the acid circulation pump B (322) of the circulation tank, and the other end is connected to the acid transfer port of the drying circulation tank (304). The acid discharge port at the bottom of the drying tower (301) is connected to the acid inlet of the drying circulation tank (304) through a pipeline. The acid circulation pump (31) of the drying tank is installed in the acid outlet at the top of the drying circulation tank (304). The outlet of the acid circulation pump (31) of the drying tank is connected to the acid inlet of the drying acid cooler (305) through a pipeline; the acid outlet of the drying acid cooler (305) is connected to the drying tower (301) through a pipeline. The acid discharge ports at the bottoms of the first absorption tower (302) and the second absorption tower (303) are respectively connected to the acid return port (510) of the first absorption circulation tank and the acid return port (511) of the second absorption circulation tank of the vertical concentrated sulfuric acid circulation tank through pipelines. The outlets of the acid circulation pump A (321) and the acid circulation pump B (322) of the circulation tank are respectively connected to the acid inlets of the first absorption acid cooler (306) and the second absorption acid cooler (307) through pipelines; the acid outlets of the first absorption acid cooler (306) and the second absorption acid cooler (307) are respectively connected to the first absorption tower (302) and the second absorption tower (303) through pipelines. A branch pipe connecting to the finished acid tank is provided on the outlet pipeline of the acid circulation pump (31) of the drying tank. A 93% finished acid outlet pipeline valve (35) is installed on the branch pipe; branch pipes connecting to the finished acid tank are respectively provided on the outlet pipelines of the acid circulation pump A (321) and the acid circulation pump B (322) of the circulation tank. 98% finished acid outlet pipeline valves (36) are installed on the branch pipes.

6. A concentrated sulfuric acid drying and absorption production system according to claim 5, characterized in that, The overflow port (4) and the acid discharge port (2) of the vertical concentrated sulfuric acid circulation tank are respectively connected to the underground tank through pipelines.

7. A concentrated sulfuric acid drying and absorption production system according to claim 5, characterized in that, Both the outlet pipelines of the acid circulation pump A (321) and the acid circulation pump B (322) of the circulation tank are connected to a small-diameter branch pipe. An acid concentration meter is installed on the small-diameter branch pipe for real-time monitoring of the acid concentration.

8. A concentrated sulfuric acid drying and absorption production system according to claim 5, characterized in that, The outlet pipeline of the acid circulation pump (31) of the drying tank is connected to a small-diameter branch pipe. An acid concentration meter is installed on the small-diameter branch pipe for real-time monitoring of the acid concentration.

9. A concentrated sulfuric acid drying and absorption production process using the concentrated sulfuric acid drying and absorption production system according to claim 5, characterized in that, comprises the following steps: (1) The 98.4 - 98.6% concentrated sulfuric acid from the first absorption tower (302) and the second absorption tower (303) enters the second cavity of the vertical concentrated sulfuric acid circulation tank (100) through the acid return port (510) of the first absorption circulation tank and the acid return port (511) of the second absorption circulation tank respectively. The 98.5% concentrated sulfuric acid entering the second cavity flows to the first cavity along the slope layer (1) through the horizontal holes (12) at the bottom of the cofferdam and is evenly mixed; (2) Start the acid circulation pump (31) of the drying tank, adjust the acid transfer amount through the acid transfer regulating valve A (37), adjust the amount of dilute acid added from the dilute acid inlet (512), and adjust the amount of makeup water added from the water inlet (59) to make the sulfuric acid concentration in the absorption circulation tank 98%; (3) The 98% concentrated sulfuric acid in the vertical concentrated sulfuric acid circulation tank (100) is respectively sent to the first absorption acid cooler (306) and the second absorption acid cooler (307) through the circulation tank acid circulation pump A (321) and the circulation tank acid circulation pump B (322). After being cooled by the acid coolers, they respectively enter the first absorption tower (302) and the second absorption tower (303) to absorb SO in the converter gas 3 , and after the concentration increases to 98.5%, it returns to the vertical concentrated sulfuric acid circulation tank (100) to complete a circulation cycle; (4) Close the valve (35) of the 93% finished acid outlet pipeline, open the valve (36) of the 98% finished acid outlet pipeline, and produce 98% concentrated sulfuric acid.

10. A concentrated sulfuric acid drying and absorption production process using the concentrated sulfuric acid drying and absorption production system described in claim 5, characterized in that, it includes the following steps: (1) The 92.4 - 92.6% concentrated sulfuric acid from the drying tower (301) enters the drying circulation tank (304); the approximately 98.5% concentrated sulfuric acid from the first absorption tower (302) and the second absorption tower (303) enters the second cavity of the vertical concentrated sulfuric acid circulation tank (100) through the acid return port (510) of the first absorption circulation tank and the acid return port (511) of the second absorption circulation tank respectively. The 98.5% concentrated sulfuric acid entering the second cavity flows to the first cavity along the slope layer (1) through the horizontal holes (12) at the bottom of the cofferdam and is evenly mixed; (2) Start the acid circulation pump A (321) or the acid circulation pump B (322) of the circulation tank, adjust the acid transfer amount through the acid transfer regulating valve B (38) to make the sulfuric acid concentration in the drying circulation tank (304) 93%; (3) The 93% concentrated sulfuric acid in the drying circulation tank (304) is sent to the drying acid cooler (305) through the 93% acid circulation pump (31) at the top of the drying circulation tank. After being cooled by the acid cooler, it is sent into the drying tower (301) to absorb H 2 O in the flue gas. After the concentration is reduced to 92.5%, it returns to the drying circulation tank (304), thus completing a cycle; (4) Close the valve (36) of the 98% finished acid outlet pipeline, open the valve (35) of the 93% finished acid outlet pipeline, and produce 93% concentrated sulfuric acid.

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