Efficient condenser for preparing sulfuric acid by wet method

Abstract

The efficient condenser comprises an acid collecting tank at the bottom, a cooling chamber in the middle and an exhaust chamber at the top end, a lower partition plate is arranged between the acid collecting tank and the cooling chamber, an upper partition plate is arranged between the cooling chamber and the exhaust chamber, and a process gas inlet is formed in the side wall of the acid collecting tank; a process gas outlet is formed in the side wall of the exhaust chamber, a condensation pipe with the two ends penetrating through the upper partition plate and the lower partition plate respectively is arranged in the cooling chamber, a cooling gas inlet is formed in the side wall of the upper portion of the cooling chamber, a cooling gas outlet is formed in the side wall of the lower portion of the cooling chamber, and the condensation pipe is of a special-shaped structure with the upper section being a corrugated pipe and the lower section being a round pipe. The corrugated pipe is arranged on the upper section of the condensation pipe, so that process gas turbulence is enhanced, the heat exchange area is increased, the heat exchange effect is improved, and the condensation amount is increased, and therefore, the condensation heat exchange efficiency of the condenser is effectively improved, the flue gas treatment capacity of the acid condenser is improved, the sulfuric acid yield is increased, and acid mist discharge is reduced.

Description

Technical Field

[0001] The invention relates to a condenser, in particular to a high-efficiency condenser used for wet-process sulfuric acid production. Background Art

[0002] In the WSA wet sulfuric acid process, the process gas containing sulfur dioxide undergoes a catalytic reaction in the conversion tower to form SO3 (hydrated and unhydrated) and water vapor, which is then condensed in the acid condenser and absorbed by the acid condenser to obtain the concentrated sulfuric acid product. In fact, inside the condenser, the water vapor only condenses in the middle and upper pipe sections, and does not condense in the lower part of the condenser pipe, but evaporates.

[0003] Most of the condenser tubes in the existing sulfuric acid condenser are conventional quartz glass tubes placed vertically. The high-temperature process gas enters the glass tube from the lower end and is cooled by air. The formed sulfuric acid flows downward along the inner wall of the glass tube and is continuously concentrated into concentrated sulfuric acid droplets that fall into the bottom acid tank. Under the existing process conditions, the heat exchange efficiency of the condenser tube (heat exchange tube) is low, and the sulfur-containing waste gas in the process gas (sulfur trioxide, water vapor, etc.) is not completely absorbed and escaped. In severe cases, the process gas enters the air side of the shell, causing corrosion of steel parts and the exhaust gas containing acid mist, and the chimney emits a lot of smoke, which eventually leads to environmental pollution incidents. This is very unfavorable to the normal operation of the acid condenser and seriously affects the normal operation of the wet sulfuric acid production process. Summary of the invention

[0004] Aiming at the problem that the condensation efficiency of sulfur-containing gas in the current wet sulfuric acid production process is low, which causes easy damage to equipment and pollutes the environment, the present invention proposes a high-efficiency condenser for wet sulfuric acid production, which improves the condensation efficiency of the gas, thereby increasing the sulfuric acid output and reducing acid mist emissions.

[0005] The technical means adopted by the present invention to solve the above problems are: a high-efficiency condenser for wet sulfuric acid production, including an acid collecting tank at the bottom, a cooling chamber in the middle and an exhaust chamber at the top, a lower baffle is provided between the acid collecting tank and the cooling chamber, an upper baffle is provided between the cooling chamber and the exhaust chamber, a process gas inlet is provided on the side wall of the acid collecting tank, a process gas outlet is provided on the side wall of the exhaust chamber, a condenser tube with two ends passing through the upper baffle and the lower baffle respectively is provided in the cooling chamber, a cooling gas inlet is provided on the side wall at the top of the cooling chamber, and a cooling gas outlet is provided on the side wall at the bottom, wherein the condenser tube is a special-shaped structure with a corrugated tube at the upper section and a round tube at the lower section. The corrugated tube can increase the condensation amount of the process gas and increase the sulfuric acid output; the special-shaped structure of the round tube can improve the heat exchange efficiency of the process gas and increase the sulfuric acid concentration.

[0006] Furthermore, the axial section of the inner wall of the bellows is in the shape of a sine wave, wherein the wavelength λ is: λ=2√2π(r+h) Where: r is the radius of the tube, h is the average liquid film thickness.

[0007] Furthermore: the length ratio of the corrugated pipe to the round pipe is 1 / 2-3 / 5.

[0008] Furthermore, the cooling chamber is also provided with a baffle with an opening end inclined downward.

[0009] Furthermore, a plurality of baffles are provided, which are staggeredly arranged in the cooling chamber from top to bottom to form a zooming structure.

[0010] Furthermore, the spacing between the baffles in the upper space of the cooling chamber is smaller than the spacing between the baffles in the lower space of the cooling chamber, so as to enhance the cooling effect of the upper part.

[0011] Furthermore, a wire mesh demister is provided above the top opening of the condenser tube.

[0012] Furthermore, the cooling chamber is also provided with an acid-conducting pipe with both ends passing through the upper partition and the lower partition respectively. The acid-conducting pipe is used to collect the acid liquid in the exhaust chamber.

[0013] Furthermore, the height of the top opening of the acid conducting tube is lower than the height of the top opening of the condensing tube.

[0014] Furthermore, the top opening of the acid conduction tube is funnel-shaped.

[0015] Furthermore, the upper partition is arranged in an inclined manner, and the inclined bottom is located at the acid guiding tube.

[0016] Furthermore, the upper partition has an inclination angle of 5-10 o .

[0017] Furthermore, an acid discharge port is provided at the bottom of the acid collecting tank.

[0018] The beneficial effects of the present invention are: 1. The present invention enhances the turbulence of process gas, increases the heat exchange area, improves the heat exchange effect, and increases the condensation and evaporation amount by setting the upper section of the condenser tube as a corrugated tube and the lower section as a special-shaped structure of a circular tube, thereby increasing the sulfuric acid output and reducing the acid mist discharge.

[0019] 2. The present invention provides a baffle with the opening end tilted downward, so that the cooling chamber presents a contraction structure, which enhances the turbulence effect of the external cold wind and is conducive to further enhancing heat exchange. This effectively improves the condensation heat exchange efficiency of the condenser, increases the flue gas processing capacity of the acid condenser, further increases the sulfuric acid output, and reduces the emission of acid mist. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front cross-sectional schematic diagram of a condenser of Example 1; Figure 2 It is a side cross-sectional schematic diagram of a condenser of Embodiment 1; Figure 3This is a schematic diagram of the arrangement of the condenser and the baffle in Example 1; Figure 4 This is a schematic diagram of the internal structure of the condenser tube in Example 1; Figure 5 This is a schematic diagram of the arrangement of the upper baffle and the acid-conducting tube in Example 1; In the figure: 1. acid collecting tank, 11. acid discharge port, 12. process gas inlet, 2. cooling chamber, 21. cooling gas outlet, 22. cooling gas inlet, 3. exhaust chamber, 31. process gas outlet, 4. upper partition, 5 wire mesh demister, 6. condenser, 61. bellows, 62. round tube, 7. baffle, 8. acid guide tube, 9. lower partition. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings. The accompanying drawings are only for illustrative purposes and are only schematic diagrams, not actual pictures, and cannot be understood as limiting the present patent; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; it is understandable to those skilled in the art that some well-known structures and their descriptions in the accompanying drawings may be omitted. Embodiment 1

[0022] A high efficiency condenser for wet process sulfuric acid production, such as Figure 1-Figure 2 As shown, the interior is composed of an acid collecting tank 1, a cooling chamber 2 and an exhaust chamber 3 from bottom to top. A vertically arranged condensing pipe 6 and an acid conducting pipe 8 are provided in the cooling chamber 2. An upper partition 4 is provided between the cooling chamber 2 and the exhaust chamber 3. A lower partition 9 is provided between the cooling chamber 2 and the acid collecting tank 1. The upper ends of the condensing pipe 6 and the acid conducting pipe 8 pass through the upper partition 4, and the lower ends pass through the lower partition 9, so as to connect the exhaust chamber 3 with the acid collecting tank 1, and the cooling chamber 2 between the exhaust chamber 3 and the acid collecting tank 1 forms a separate space.

[0023] like Figure 2 As shown, a wire mesh demister 5 is also provided above the top open end of the condenser 6 to collect and remove the acid mist in the sulfur-containing process gas. The wire mesh demister 5 can be made of polytetrafluoroethylene, and the outer periphery is in contact with the inner wall of the exhaust chamber 3 to ensure that the process gas is discharged from the wire mesh demister 5 after collecting some of the residual acid mist. A cooling gas inlet 22 is provided on the side wall above the cooling chamber 2, and a cooling gas outlet 21 is provided on the side wall below. The cooling gas enters the cooling chamber 2 from the cooling gas inlet 22 above, flows downward, and flows out from the cooling gas outlet 21 below after heat exchange with the process gas in the condenser 6.

[0024] At the same time, a process gas inlet 12 is provided on the side wall of the acid collecting tank 1, a process gas outlet 31 is provided on the side wall of the exhaust chamber 3, and an acid discharge port 11 is provided at the bottom of the acid collecting tank 1. After the sulfur-containing process gas enters from the process gas inlet 12, it rises along the condenser 6. During the rising process, it exchanges heat with the cooling air outside the condenser 6 and condenses to form liquid, which flows into the acid collecting tank 1. The uncondensed process gas passes through the wire mesh demister 5 to further remove the acid mist and then enters the exhaust chamber 3. It is intercepted and condensed again at the top of the exhaust chamber 3 and is discharged along the process gas outlet 31.

[0025] like Figure 2 and Figure 3 As shown, a plurality of baffles 7 are provided in the cooling chamber 2, one end of the baffle 7 is close to the wall of the cooling chamber 2, and the other end is inclined downward, and from the axial section, the baffles 7 are provided on both side walls, and are arranged alternately in sequence. In this embodiment, the angle θ of the baffle 7 downwardly inclined is 15 o , so that the interior of the cooling chamber is in a contraction structure to enhance the turbulence effect of the cooling gas, improve the heat exchange efficiency inside and outside the condenser tube 6, and improve the heat exchange capacity between the cooling gas and the process gas. At the same time, the baffles 7 are arranged in a non-equidistant manner in the cooling chamber 2, and the distance m between two adjacent baffles 7 in the upper space is smaller than the distance n between two adjacent baffles 7 in the lower space. In this embodiment, m is 835mm and n is 1120mm. The baffles 7 in the upper part are densely arranged, which further enhances the cooling effect of the upper part of the condenser, increases the sulfuric acid output, and thus reduces the acid mist discharge.

[0026] like Figure 2-Figure 4 As shown, the condenser 6 is a special-shaped structure of an upper bellows 61 and a lower round tube 62. Both the bellows 61 and the round tube 62 can be made of high borosilicate glass or quartz. The high borosilicate glass or quartz has high temperature resistance and acid corrosion resistance and a longer service life. The axial cross-section of the inner wall of the bellows 61 is a sinusoidal wave shape, and the sine wave wavelength λ is: λ=2√2π(r+h) where: r is the radius of the round tube, and h is the average liquid film thickness. In this embodiment, the length ratio between the bellows 61 and the round tube 62 is set to a:b=4:3, the bellows 61 is 4m long, the round tube 62 is 3m long, and the total length of the condenser 6 is 7m. Due to the instability of the gas-liquid interface, the liquid film on the surface of the bellows 61 will gather locally to form droplets. The bellows 61 uses this unstable effect caused by surface tension that can affect the shape of the thin liquid film on the surface of the round tube to make the liquid film distribution of different thickness appear on the surface of the condenser tube, thin the liquid film to enhance condensation heat exchange. At the same time, the process gas turbulence in the tube is enhanced, the heat exchange area is increased, and the heat exchange effect is improved, thereby increasing the flue gas treatment capacity of the acid condenser, increasing the sulfuric acid production, and reducing the emission of acid mist.

[0027] like Figure 5As shown, the upper partition 4 is inclined. In this embodiment, the inclination angle α is 10 o , and the inclined bottom end is located at the opening of the acid-conducting tube 8, so that the acid collected at the top of the exhaust chamber 3 is collected in the acid-conducting tube 8, and then flows into the acid collecting tank 1 for collection. In addition, the top opening of the acid-conducting tube 8 is in the shape of a funnel, and the height of the top opening is lower than the height of the top opening of the condensing tube 6, so as to better collect the acid in the exhaust chamber 3.

[0028] In order to further verify the condensation effect of the present invention, the condensation effects of different condensing tubes were tested, and the results are as follows: The test device uses a condenser with a single row of 28 condensing tubes. Under the same test conditions, the condensation effect of the condensing tubes is explored. The test results are shown in the table:

[0029] It can be seen from the experimental data table in Table 1 that as the value of a:b increases, the sulfur trioxide concentration at the process gas outlet continues to decrease, and the single-tube sulfuric acid collection amount continues to increase. Compared with a:b of 0 / 1, when a:b is 1 / 2, the single-tube sulfuric acid collection amount increases by 19.6%, and the sulfur trioxide concentration at the process gas outlet decreases by 33.3%.

[0030] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Technicians in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the present invention, and the protection scope of the present invention should be defined by the claims.

Claims

1. A high-efficiency condenser for wet-process sulfuric acid production, comprising an acid collecting tank (1) at the bottom, a cooling chamber (2) in the middle, and an exhaust chamber (3) at the top, a lower baffle (9) being provided between the acid collecting tank (1) and the cooling chamber (2), an upper baffle (4) being provided between the cooling chamber (2) and the exhaust chamber (3), a process gas inlet (12) being provided on the side wall of the acid collecting tank (1), a process gas outlet (31) being provided on the side wall of the exhaust chamber (3), a condensation pipe (6) being provided in the cooling chamber (2) with two ends passing through the upper baffle (4) and the lower baffle (9) respectively, a cooling gas inlet (21) being provided on the side wall at the top of the cooling chamber (2), and a cooling gas outlet (21) being provided on the side wall at the bottom, wherein: The condenser tube (6) is a special-shaped structure in which the upper section is a corrugated tube (61) and the lower section is a round tube (62).

2. The high-efficiency condenser for wet sulfuric acid production according to claim 1, characterized in that: The axial cross section of the inner wall of the bellows (61) is in the shape of a sine wave, wherein the wavelength λ is: λ=2√2π(r+h) Where: r is the radius of the tube, h is the average liquid film thickness.

3. The high-efficiency condenser for wet sulfuric acid production according to claim 1, characterized in that: The length ratio of the corrugated tube (61) to the circular tube (62) is 1 / 2-3 / 5.

4. The high-efficiency condenser for wet sulfuric acid production according to claim 1, characterized in that: The cooling chamber (2) is further provided with a baffle (7) with an opening end inclined downward.

5. The high-efficiency condenser for wet sulfuric acid production according to claim 4, characterized in that: A plurality of baffles (7) are provided, which are staggeredly arranged from top to bottom in the cooling chamber (2).

6. The high-efficiency condenser for wet sulfuric acid production according to claim 5, characterized in that: The spacing between the baffles (7) in the upper space of the cooling chamber (2) is smaller than the spacing between the baffles (7) in the lower space of the cooling chamber (2).

7. The high-efficiency condenser for wet sulfuric acid production according to claim 1, characterized in that: A wire mesh demister (5) is provided above the top opening of the condenser tube (6).

8. The high-efficiency condenser for wet sulfuric acid production according to claim 1, characterized in that: An acid-conducting tube (8) is also provided in the cooling chamber (2), with both ends passing through the upper partition (4) and the lower partition (9) respectively. The height of the top opening of the acid-conducting tube (8) is lower than the height of the top opening of the condensing tube (6), and the top opening of the acid-conducting tube (8) is funnel-shaped.

9. The high-efficiency condenser for wet-process sulfuric acid production according to claim 8, characterized in that: The upper partition (4) is arranged in an inclined manner, and the bottom of the inclined manner is located at the acid guide tube (8). The inclination angle of the upper partition (4) is 5-10 o .

10. The high-efficiency condenser for wet-process sulfuric acid production according to claim 1, characterized in that: An acid discharge port (11) is provided at the bottom of the acid collecting tank (1).

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