Hydrogen sulfide combustion furnace for preparing sulfuric acid by wet method

Abstract

A hydrogen sulfide combustion furnace for preparing sulfuric acid through a wet method comprises a furnace body, a combustor, a smoke outlet and a tracery wall, the combustor and the smoke outlet are arranged at the two ends of the furnace body, the tracery wall is arranged in the furnace body and located at the smoke outlet end, the tracery wall is mainly composed of solid refractory bricks and hollow refractory bricks, and the solid refractory bricks are arranged on the portion, close to the inner wall of the furnace body, of the tracery wall. Hollow refractory bricks with through holes in the middle are arranged at the part far away from the inner wall, meanwhile, gaps are formed between the hollow refractory bricks in the same horizontal direction and the adjacent hollow refractory bricks, and through holes are also formed in the gaps. The door-shaped channel is arranged in the tracery wall, maintenance is convenient, the solid refractory bricks and the hollow refractory bricks are used at the same time, the tracery wall can be well supported, the gaps between the hollow refractory bricks are matched, the different ventilation rate requirements can be met, the combustion requirements of hydrogen sulfide gas with different concentrations are met, and gas combustion is more sufficient.

Description

Technical Field

[0001] The invention relates to a hydrogen sulfide combustion furnace, in particular to a hydrogen sulfide combustion furnace for preparing sulfuric acid by a wet process. Background Art

[0002] Wet sulfuric acid production is a process that uses hydrogen sulfide gas as raw material to directly produce sulfuric acid by wet contact method. This method can effectively utilize hydrogen sulfide gas generated in various production processes to directly produce acid to obtain high-concentration sulfuric acid. It has the advantages of wide application range, relatively simple process flow, high sulfur recovery rate, low operating cost and good economic benefits. The hydrogen sulfide combustion furnace is the key equipment for converting hydrogen sulfide into sulfur dioxide in the wet sulfuric acid production. In the combustion process of hydrogen sulfide gas, theoretically, when the molar ratio of hydrogen sulfide gas to oxygen is 2:3, all hydrogen sulfide gas can be converted into sulfur dioxide and water. However, in actual operation, since it is difficult for the gas in the furnace to reach a very uniform state, hydrogen sulfide gas at some positions will not be fully contacted with oxygen, but will contact and react with sulfur dioxide gas to form sulfur. For the combustion furnace that needs to run for a long time, even if the amount of sulfur generated each time is very small, the long-term operation accumulation will seriously cause the subsequent waste heat recovery boiler pipe to be blocked and affect the production of sulfuric acid. Therefore, in actual production, the amount of oxygen introduced into the furnace body is usually four times that of hydrogen sulfide gas to minimize the generation of sulfur. However, this will result in too low a process temperature after the reaction, which is not convenient for subsequent heat recovery and will also increase the emission of waste gas during sulfuric acid production. Therefore, it is necessary to improve the uniformity of gas mixing in the combustion furnace. The structural design and layout of the flower wall are particularly important for the combustion stability and flow field distribution in the furnace, but the existing hydrogen sulfide combustion furnace does not focus on this point. Summary of the invention

[0003] Aiming at the problem of poor gas flow in the current hydrogen sulfide combustion furnace, the present invention proposes a hydrogen sulfide combustion furnace for preparing sulfuric acid by wet process, which can improve the hydrogen sulfide gas conversion efficiency and adjust the uniformity of flow field distribution in the furnace.

[0004] The technical means adopted by the present invention to solve the above problems are: a hydrogen sulfide combustion furnace for wet sulfuric acid production, comprising a furnace body and a burner and a flue gas outlet arranged at both ends of the furnace body, and a flower wall arranged inside the furnace body at the flue gas outlet end, wherein the flower wall is mainly composed of solid refractory bricks and hollow refractory bricks, and the flower wall is arranged with solid refractory bricks near the inner wall of the furnace body, and the hollow refractory bricks with through holes in the middle are arranged at the part away from the inner wall, and at the same time, there is a gap between the hollow refractory bricks in the same horizontal direction and the adjacent hollow refractory bricks, and through holes are also formed in the gap. By adjusting the number of solid refractory bricks and hollow refractory bricks, the size of the through holes of the hollow refractory bricks, and the gaps between the hollow refractory bricks, the ventilation rate of the entire flower wall is adjusted to adapt to the combustion of hydrogen sulfide gas at different concentrations or different processing volumes.

[0005] Furthermore, the hollow refractory bricks in the same flower wall have the same specifications, and the gaps between two adjacent hollow refractory bricks are equal, so as to ensure that the air permeability of the entire flower wall is equal as much as possible, and better improve the uniformity of gas mixing in the furnace body.

[0006] Furthermore, a door-shaped passage is arranged on the flower wall, and hollow refractory bricks are arranged in the door-shaped passage. There is a gap between the hollow refractory bricks in the same horizontal direction and the adjacent hollow refractory bricks, and through holes are also formed in the gaps.

[0007] Further, a door-type passage is arranged at a position below the flower wall.

[0008] Furthermore, the hollow refractory brick is a rectangular parallelepiped as a whole, the through hole is a circular hole, and the cross section of the hollow refractory brick located in the radial direction of the through hole is a square, so as to guide and distribute the airflow.

[0009] Furthermore, a choke is provided in the furnace body at one end of the burner.

[0010] Furthermore, a first flower wall is provided in the furnace body near the smoke outlet, and a second flower wall is provided between the choke and the first flower wall.

[0011] Furthermore, the ventilation rate of the first flower wall is 40-45%, the ventilation rate of the second flower wall is greater than that of the first flower wall, and the distance between the first flower wall and the second flower wall is 1 / 4-1 / 3 of the length of the furnace body.

[0012] Furthermore, a third flower wall is provided between the choke and the second flower wall, the air permeability of the third flower wall is greater than that of the second flower wall, and the distance between the second flower wall and the third flower wall is 1 / 4-1 / 3 of the length of the furnace body.

[0013] Furthermore, the burner includes a shell, an outer wall of the shell is provided with an air inlet, an end of the shell is provided with a hydrogen sulfide gas inlet and an auxiliary gas inlet extending into the shell, an inner wall of the shell is provided with an annular tube connected to the air inlet, and an outer wall inside the annular tube is provided with a plurality of swirl diffuser tubes connected to the annular tube, and the plurality of swirl diffuser tubes are evenly arranged along the circumference of the annular tube.

[0014] Furthermore, the angle between the axial direction of the swirl diffuser and the axial direction of the shell is 15-30 o The angle between the axial direction of the swirl diffuser and the tangent direction of the annular tube is 35 o -45 o .

[0015] Furthermore, the diameter of the air outlet at the end of the swirl diffuser is 150-250 mm.

[0016] Further, the number of the cyclone diffuser tubes is four, six, eight or twelve.

[0017] Furthermore, the hydrogen sulfide gas inlet and the auxiliary gas inlet are arranged in a ring shape, the hydrogen sulfide gas inlet is located at the inner ring, the auxiliary gas inlet is located at the outer ring, and the gas outlet positions are both located inside the ring surrounded by the gas outlet of the swirl diffuser.

[0018] Furthermore, the diameter of the gas outlet of the hydrogen sulfide gas inlet is 50-100 mm, and the diameter of the gas outlet of the auxiliary gas inlet is 70-170 mm.

[0019] Further, the number of the hydrogen sulfide gas inlets is four, eight or twelve.

[0020] Further, the number of the auxiliary gas inlets is eight, twelve or sixteen.

[0021] Furthermore, the distance between the hydrogen sulfide gas inlet and its adjacent auxiliary gas inlet is 100-300 mm.

[0022] The beneficial effects of the present invention are: 1. The solid refractory bricks and hollow refractory bricks of the pattern wall of the present invention are used simultaneously, and the gaps between the hollow refractory bricks can meet different ventilation rate requirements, and then meet the combustion requirements of hydrogen sulfide gas of different concentrations, so that the gas burns more fully. By changing the internal structure of the combustion furnace, the conversion efficiency of hydrogen sulfide gas and the uniformity of the flow field distribution in the furnace can be improved.

[0023] 2. The present invention makes the air permeability in the same flower wall as uniform as possible and ensures the stability of the flow field as much as possible.

[0024] 3. The burner of the present invention adopts a plurality of swirl diffusers arranged in an annular manner, and cooperates with the annular hydrogen sulfide gas inlet and the auxiliary gas inlet, which can promote the full mixing of hydrogen sulfide, sulfur-containing flash gas and air, promote the full combustion reaction, reduce the excess air coefficient, improve the hydrogen sulfide reaction treatment efficiency and the concentration and temperature uniformity of sulfur dioxide gas after combustion in the combustion furnace, and provide more energy-saving process conditions for the subsequent sulfur dioxide catalytic reaction to sulfur trioxide. At the same time, the wall-attached wind formed can also reduce the temperature of the inner wall of the furnace body, and play a protective role on the inner wall of the furnace body.

[0025] 4. The present invention can increase the angular velocity of air in the circumferential direction by arranging the swirl diffuser at an angle in the burner, so that the air and hydrogen sulfide gas can be better mixed and the combustion can be more complete. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of the combustion furnace in Example 1; Figure 2 This is a schematic diagram of the flower wall structure of Example 1; Figure 3 This is a schematic diagram of the burner structure of Example 1; Figure 4 This is a schematic structural diagram of the burner of Example 1 from another angle; In the figure: 1. burner, 11. shell, 12. air inlet, 13. hydrogen sulfide gas inlet, 14. auxiliary gas inlet, 15. swirl diffuser, 16. annular tube, 2. furnace body, 3. choke, 4. first flower wall, 41. door-type channel, 42. solid refractory brick, 43. hollow refractory brick, 44. gap, 5. second flower wall, 6. third flower wall, 7. flue gas outlet. DETAILED DESCRIPTION

[0027] 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

[0028] A hydrogen sulfide combustion furnace for wet sulfuric acid production, such as Figure 1 As shown, the furnace body 2 includes a burner 1, a choke 3, a third flower wall 6, a second flower wall 5, a first flower wall 4 and a flue gas outlet 7. The concentration of hydrogen sulfide gas treated in this embodiment is about 27-38%, which is a low-concentration acid gas. Therefore, the internal structure of the furnace body 2 with multiple flower walls is adopted.

[0029] The furnace body 2 of this embodiment is about 95000mm long and has a radius of about 4500mm. The choke 3 is placed at the rear end of the burner 1, at a distance of about 32000mm, which is about 1 / 3 of the length of the furnace body. The presence of the choke 3 allows the flue gas to flow back to the front end of the combustion furnace, prolonging the residence time of the flue gas in the furnace, promoting the full combustion reaction, and improving the combustion conversion efficiency. The first flower wall 4 is placed close to the rear end of the furnace body 2, at a distance of 1000mm-3500mm from the flue gas outlet 7. The second flower wall 5 and the third flower wall 6 are placed in the middle of the furnace body 2, with a distance of 1500mm-5000mm between the flower walls. The flower wall spacing is adjusted by the number of flower walls placed and the amount of hydrogen sulfide treated to better improve the conversion rate of hydrogen sulfide gas.

[0030] like Figure 2As shown, a door-shaped passage 41 for maintenance is provided at the bottom of the flower wall, and the height range is 800-1500mm. In this embodiment, the top of the door-shaped passage 41 adopts a square structure, and of course other structures such as a round arch structure can also be adopted. The door-shaped passage 41 and the flower wall are both made of solid refractory bricks 42 and hollow refractory bricks 43. The solid refractory bricks 42 are arranged at the part of the flower wall close to the inner wall of the furnace body 2, and the hollow refractory bricks 43 with through holes in the middle are arranged at the part away from the inner wall. Hollow refractory bricks 43 are also arranged in the door-shaped passage 41. The hollow refractory bricks 43 used in the same flower wall and its door-shaped passage 41 have the same specifications, and a gap 44 is provided between two adjacent hollow refractory bricks 43 in the same horizontal direction, and a through hole is also formed at the gap 44 as a gas passage. The hollow refractory brick 43 is a rectangular solid with a length of about 300 mm and is arranged along the length of the furnace body 2. The cross section along the radial direction of the furnace body 2 is a square with a side length of about 240 mm, and a circular through hole with a diameter of about 100-180 mm is provided at the center. The ventilation rate of the entire flower wall 4 can be adjusted by adjusting the ratio between the hollow refractory brick 43 and the solid refractory brick 42 and the size of the gap 44 between the hollow refractory bricks 43.

[0031] The through holes of the hollow refractory bricks 43 arranged in the flower wall 4 and the gaps 44 between the hollow refractory bricks 43 form a porous airflow guide and distribution, improve the uniformity of the temperature, velocity and concentration of the airflow in the furnace, and prolong the time that the smoke stays in the furnace. In short, by adjusting the opening size of the hollow refractory bricks 43, the spacing between the hollow refractory bricks 43, the height range and ventilation range of the door-type channel 41, the overall ventilation rate of the first flower wall 4 is 44.5%, the ventilation rate of the second flower wall 5 is 48.2%, and the ventilation rate of the third flower wall 6 is 53.1%. The closer the flower wall is placed to the gas inlet at the front end of the furnace body 2, the higher the ventilation rate, and the closer it is to the smoke outlet at the rear end of the furnace body 2, the smaller the ventilation rate. The smoke passes from the flower wall with high ventilation rate to the flower wall with low ventilation rate, which can reduce the pressure drop in the furnace and make the pressure distribution in the furnace more uniform. When the concentration of hydrogen sulfide is high, only one flower wall 4 can be set near the smoke outlet 7.

[0032] like Figure 3 As shown, the burner 1 includes a cylindrical shell 11, an air inlet 12 is provided at the upper side wall of the outer periphery of the shell 11, and an annular tube 16 connected to the air inlet 12 is provided on the inner side of the shell 11, and air enters the annular tube 1 from the air inlet 2 from top to bottom. The outer side wall of the annular inner part surrounded by the annular tube 16 is provided with a plurality of swirl diffuser tubes 15 connected to the annular tube 16. In this embodiment, there are eight swirl diffuser tubes 15, which are evenly arranged along the circumferential direction, and each swirl diffuser tube 15 forms a certain angle with the shell 11. In this embodiment, the angle between the axial direction of the swirl diffuser tube 15 and the axial direction of the shell 11 is 25 o (It can also be 15-30o The angle between the axial direction of the swirl diffuser 15 and the tangent direction of the annular tube 16 is 40 o (It can also be 35 o -45 o In this way, the air can enter the burner 1 at a certain angle to form a swirl, which is beneficial to the mixing of the air and the process gas.

[0033] like Figure 4 As shown, a hydrogen sulfide gas inlet 13 and an auxiliary gas inlet 14 extending into the shell 11 are provided at the end of the shell 11. Figure 3 As shown, there are multiple hydrogen sulfide gas inlets 13 and auxiliary gas inlets 14, all of which are evenly arranged in a ring shape, and the hydrogen sulfide gas inlet 13 is located at the inner circle of the ring, the auxiliary gas inlet 14 is located at the outer circle of the ring, and the gas outlet of the swirl diffuser 15 is located at the outer circle of the auxiliary gas inlet 14. In this embodiment, there are four hydrogen sulfide gas inlets 13, and the diameter of the corresponding gas outlet is 50mm; there are eight auxiliary gas inlets 14, and the diameter of the corresponding gas outlet is 70mm. The distance between the hydrogen sulfide gas inlet 13 and its adjacent auxiliary gas inlet 14 is 100mm. The auxiliary gas surrounds the hydrogen sulfide gas, and cooperates with the air entering at an angle to better mix the gases together, so that the combustion reaction can proceed more fully.

[0034] Of course, according to the different concentrations of hydrogen sulfide gas, different numbers of cyclone diffusers 15 can be selected, such as four, six, or twelve, so that different amounts of air can be introduced according to different amounts of hydrogen sulfide. At the same time, different numbers of hydrogen sulfide gas inlets 13 can also be selected, such as eight or twelve, etc. Different numbers of auxiliary gas inlets 14 can also be selected, such as twelve or sixteen, etc. Moreover, the distance between the hydrogen sulfide gas inlet 13 and the auxiliary gas inlet 14 can also be adjusted, and the adjustment range can be 100-300 mm.

[0035] In the wet acid production operation, before hydrogen sulfide is introduced into the combustion furnace, the combustion furnace must be preheated to ensure flame stability. During the preheating process, the hydrogen sulfide gas inlet 13 is first closed, and the auxiliary gas inlet 14 provides auxiliary gas and air for mixed combustion. When the temperature in the combustion furnace reaches about 900°C, the introduction of auxiliary gas is stopped, and sulfur-containing flash gas is introduced instead to provide sulfur-containing flash gas with less hydrogen sulfide in the furnace. At the same time, the hydrogen sulfide inlet 13 is opened to provide Claus gas with a higher concentration of hydrogen sulfide to start the combustion process of hydrogen sulfide. This method of setting the hydrogen sulfide air inlet as an inner and outer double-circle air intake form combined with the air diffusion intake form, the air with circumferential angular velocity will rotate in the furnace with the annular intake hydrogen sulfide, which increases the residence time of the combustion flue gas in the furnace, promotes the combustion of hydrogen sulfide, and makes the flue gas concentration distribution at the final outlet more uniform.

[0036] After testing, the amount of oxygen required and the sulfur dioxide output of the combustion furnace of this embodiment at different hydrogen sulfide gas concentrations are as follows: The hydrogen sulfide gas treatment capacity is 2200m 3 / h, hydrogen sulfide concentration is 27-38%; air volume is 14300m 3 / h; the volume ratio of hydrogen sulfide gas to air is 1:6.5; the sulfur dioxide conversion rate reaches 99%; the output is about 2000kg / h.

[0037] 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 hydrogen sulfide combustion furnace for wet sulfuric acid production, comprising a furnace body (2), a burner (1) and a flue gas outlet (7) arranged at both ends of the furnace body (2), and a flower wall arranged inside the furnace body (2) at the end of the flue gas outlet (7), characterized in that: The pattern wall is mainly composed of solid refractory bricks (42) and hollow refractory bricks (43). The solid refractory bricks (42) are arranged at the position of the pattern wall close to the inner wall of the furnace body (2), and the hollow refractory bricks (43) with through holes in the middle are arranged at the position away from the inner wall. At the same time, there is a gap (44) between the hollow refractory bricks (43) and the adjacent hollow refractory bricks (43) in the same horizontal direction, and a through hole is also formed at the gap (44).

2. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 1, characterized in that: The hollow refractory bricks (43) in the same decorative wall have the same specifications, and the gaps (44) between two adjacent hollow refractory bricks (43) are equal.

3. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 1, characterized in that: A door-shaped passage (41) is provided on the flower wall, and hollow refractory bricks (43) are arranged in the door-shaped passage (41). There is a gap (44) between the hollow refractory bricks (43) and the adjacent hollow refractory bricks (43) in the same horizontal direction, and a through hole is also formed at the gap (44).

4. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 1, characterized in that: The hollow refractory brick (43) is a rectangular parallelepiped as a whole, its through hole is a circular hole, and the cross section of the hollow refractory brick (43) located in the radial direction of the through hole is a square.

5. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 1, characterized in that: A choke (3) is provided at one end of the burner (1) in the furnace body (2), a first flower wall (4) is provided at a position close to the smoke outlet (7) in the furnace body (2), and a second flower wall (5) is provided between the choke (3) and the first flower wall (4).

6. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 5, characterized in that: The ventilation rate of the first flower wall (4) is 40-45%, the ventilation rate of the second flower wall (5) is greater than the ventilation rate of the first flower wall (4), and the distance between the first flower wall (4) and the second flower wall (5) is 1 / 4-1 / 3 of the length of the furnace body (2).

7. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 6, characterized in that: A third flower wall (6) is provided between the choke coil (3) and the second flower wall (5); the air permeability of the third flower wall (6) is greater than that of the second flower wall (5); and the distance between the second flower wall (5) and the third flower wall (6) is 1 / 4 to 1 / 3 of the length of the furnace body (2).

8. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 1, characterized in that: The burner (1) comprises a shell (11), an outer side wall of the shell (11) is provided with an air inlet (12), an end of the shell (11) is provided with a hydrogen sulfide gas inlet (13) and an auxiliary gas inlet (14) extending into the shell (11), an inner side wall of the shell (11) is provided with an annular tube (16) connected to the air inlet (12), and an outer side wall inside the annular tube (16) is provided with a plurality of swirl diffuser tubes (15) connected to the annular tube (16), and the plurality of swirl diffuser tubes (15) are evenly arranged along the circumference of the annular tube (16).

9. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 8, characterized in that: The angle between the axial direction of the swirl diffuser (15) and the axial direction of the shell (11) is 15-30 o The angle between the axial direction of the swirl diffuser (15) and the tangent direction of the annular tube (16) is 35 o -45 o .

10. The hydrogen sulfide combustion furnace for wet sulfuric acid production according to claim 8, characterized in that: The hydrogen sulfide gas inlet (13) and the auxiliary gas inlet (14) are both arranged in a ring shape, the hydrogen sulfide gas inlet (13) is located at the inner ring of the ring, the auxiliary gas inlet (14) is located at the outer ring of the ring, and the gas outlet positions are both located inside the ring formed by the gas outlet of the cyclone diffuser (15).

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