Low-concentration acid gas ammonia burning sulfur production equipment and control method thereof

Abstract

This invention discloses a low-concentration acid gas ammonia-to-sulfur production equipment and its control method. The ammonia-to-sulfur production equipment includes a shell, a central fuel gas spray gun, a central low-concentration clean acid gas spray gun, a combustion air assembly, a first acid gas inlet assembly, a combustion oxygen inlet assembly, an ignition gun, a speed-up ring, and a second acid gas inlet assembly. This invention uses a combination of combustion air and pure oxygen as combustion aids, with zoned control of the combustion air and pure oxygen. The equipment is divided into a complete combustion zone and an oxygen-deficient combustion zone. In the complete combustion zone, the fuel gas and combustion air are completely combusted, releasing heat and generating high-temperature flue gas, which helps to increase the combustion temperature of the low-concentration acid gas. By adjusting the fuel quantity, the reaction temperature can reach above 1250℃, meeting the requirements for NH3 combustion. The oxygen-deficient combustion zone uses low-concentration clean acid gas and low-concentration ammonia-containing gas as fuel gas, and uses pure oxygen for combustion aid, which can reduce the influence of N2 on the reaction temperature and further increase the reaction temperature.

Description

Technical Field

[0001] This invention relates to the field of petrochemical equipment technology, specifically to a low-concentration acid gas ammonia-to-sulfur production equipment and its control method. Background Technology

[0002] In the coal chemical industry, if acidic gas (low H2S content) enters the Claus sulfur production unit in a low-temperature methanol washing unit, a series of severe process challenges will be encountered. The main reason is that the Claus reaction has specific requirements for reactant concentration and temperature; low concentration means it is difficult to maintain the system's self-heating balance and high conversion rate.

[0003] The challenge is the excessively low furnace temperature. The first step of the Claus reaction is the combustion of H2S in the acidic gas to produce SO2 in the furnace, an exothermic reaction that provides the heat source for the entire unit. When the H2S concentration is low, the heat released by combustion is significantly reduced. If the concentration is below 30%~40% (volume fraction), the released heat is insufficient to even maintain the minimum operating temperature of the furnace (typically >1000℃).

[0004] If the furnace temperature is too low, hydrocarbons (such as CH4) in the acid gas will not burn completely, resulting in carbon black from cracking. Carbon black contaminates the catalyst, leading to catalyst deactivation and increased bed resistance.

[0005] If the acidic gas contains ammonia (NH3), the ammonia cannot decompose at low temperatures and will react with SO2 to produce ammonium bisulfate or ammonium sulfate, causing serious blockage of downstream waste heat boilers and pipelines.

[0006] Low concentrations of acidic gas mean a lower partial pressure of sulfur in the process gas, which, according to chemical equilibrium principles, discourages the Claus reaction from proceeding towards sulfur formation. The overall sulfur recovery rate of the unit decreases significantly, making it difficult to meet design targets. Excessive SO2 content in the tail gas increases the load on the tail gas treatment unit and complicates environmental compliance.

[0007] In the coal chemical industry, the H2S concentration in the acidic gas from low-temperature methanol washing is low, typically below 30%, and it also contains NH3. The sulfur production furnace needs to meet the conditions for ammonia combustion, requiring a furnace temperature of 1250℃. To achieve this, methods such as acidic gas preheating, pure oxygen combustion, acidic gas diversion, and supplementary fuel gas are commonly used to increase the reaction temperature. However, when the acidic gas concentration is below 30%, even using these methods simultaneously may not achieve the required ammonia combustion temperature, and may also lead to some adverse consequences.

[0008] H2S in acidic gases can cause high-temperature sulfur corrosion under high-temperature conditions. Generally, the preheating temperature of acidic gases does not exceed 200℃, which has a limited effect on increasing the reaction temperature.

[0009] Combustion using pure oxygen results in a higher reaction temperature than combustion using air. However, even with a sour gas (H2S) concentration below 30%, reaching the ammonia combustion temperature under pure oxygen conditions is extremely difficult.

[0010] In scenarios where the H2S content in the acidic gas from low-temperature methanol washing is low, increasing the combustion furnace temperature by supplementing with fuel gas introduces a series of shortcomings and limitations. The Claus reaction in the sulfur production furnace is an anaerobic reaction; H2S has a low ignition point and reacts more readily with oxygen than hydrocarbons. The fuel gas (mainly composed of CH4 and other hydrocarbons) easily generates intermediate products CO and carbon black due to anaerobic combustion. Large amounts of supplementary fuel may result in a less significant increase in reaction temperature, and the carbon black affects sulfur quality, producing black sulfur.

[0011] Meanwhile, the difficulty of air distribution control increases dramatically. The core control requirement of the Claus process is to maintain the molar ratio of H2S to SO2 at 2:1, which requires precise control of the ratio of acid gas to air. After supplementing fuel gas, if the air distribution is inaccurate, the fuel gas will not burn completely, producing carbon black, which will contaminate the catalyst and clog the equipment; at the same time, the incomplete combustion of H2S will reduce the subsequent sulfur conversion rate.

[0012] Reference 1: Chinese patent document with publication number CN117303319A.

[0013] Reference 1 describes a supplementary combustion sulfur-producing burner, comprising a shell, a main gas gun, an acid gas gun, a supplementary combustion gas gun, and a main combustion air duct. An air guide duct is located inside the shell, with a main fire channel at the end of the air guide duct and an ignition gun mounted on the main fire channel. A combustion chamber is located inside the air guide duct, with an acid gas gun inside the combustion chamber and a main gas gun inside the acid gas gun. A supplementary combustion channel is located within the lining surrounding the main fire channel, and a supplementary combustion gas gun and a supplementary combustion air gun are installed within the supplementary combustion channel. The supplementary combustion gas gun and supplementary combustion air gun are used to supply high-temperature flue gas to the main fire channel. In this supplementary combustion sulfur-producing burner, the supplementary combustion gas and supplementary combustion air are completely combusted within the supplementary combustion channel before entering the main fire channel, releasing all heat. On the one hand, while maintaining the same acid gas sulfur-producing principle, this ensures the total flue gas temperature reaches the temperature required for the sulfur-producing process, improving sulfur recovery rate. On the other hand, the completely combusted gas avoids the formation of carbon black, thereby improving sulfur quality.

[0014] While the aforementioned burner can pre-ignite by mixing some air with the combustion gas from the afterburner nozzle, thus contributing to increased reaction temperature, the short reaction residence time due to the nozzle's placement inside the refractory lining means that the combustible gas cannot fully react within the relatively short refractory material. Furthermore, the flame zone can easily cause overheating within the lining, potentially damaging the burner cylinder. Additionally, this burner cannot utilize oxygen-enriched or pure oxygen processes to further increase the reaction temperature, largely due to the limitation that the concentration of acidic gas cannot be too low. Summary of the Invention

[0015] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide a low-concentration acid gas ammonia-to-sulfur production equipment and its control method.

[0016] To address the shortcomings of the aforementioned technical problems, the present invention provides a low-concentration acid gas ammonia-to-sulfur production device, comprising: The casing, from front to back, comprises a complete combustion zone, an oxygen-deficient combustion zone, a pre-reaction zone, and a post-reaction zone; and Central fuel gas nozzle; and A central low-concentration clean acid gas spray gun, which surrounds a central fuel gas spray gun and is coaxially arranged with the central fuel gas spray gun; and A combustion air assembly includes a combustion air collection chamber, a combustion air distributor, and a combustion air cyclone separator. The combustion air collection chamber is enclosed by a central low-concentration clean acid gas spray gun. The combustion air distributor and the combustion air cyclone separator are arranged within the combustion air collection chamber along the airflow direction. A first acid gas intake assembly includes a first low-concentration acid gas collection chamber, a plurality of acid gas nozzles, and a low-concentration acid gas cyclone separator. The first low-concentration acid gas collection chamber surrounds the outside of the complete combustion zone. The plurality of acid gas nozzles connect the first low-concentration acid gas collection chamber to the oxygen-deficient combustion zone. The low-concentration acid gas cyclone separator is arranged at the outlet of the acid gas nozzles. A combustion-supporting oxygen intake assembly includes a combustion-supporting oxygen collection chamber and several combustion-supporting oxygen spray nozzles. One end of each spray nozzle is connected to the combustion-supporting oxygen collection chamber, and the other end passes through an acidic gas collection chamber and an acidic gas cyclone separator to connect with an oxygen-deficient combustion zone. A lighter, the ignition tip of which extends into the zone of complete combustion; and The acceleration ring is positioned between the front and rear reaction zones; and The second acid gas intake assembly includes a second acid gas collection chamber and several low-concentration cleaning acid gas spray guns, which connect the second acid gas collection chamber to the internal area of ​​the speed-up ring.

[0017] As a further optimization of the low-concentration acid gas ammonia-to-sulfur production equipment of the present invention: the angle between the acid gas nozzle and the axis of the equipment is 20°~40°.

[0018] As a further optimization of the low-concentration acid gas-fired ammonia-to-sulfurization equipment of the present invention: the number of combustion-supporting oxygen spray guns is 4 to 8.

[0019] As a further optimization of the low-concentration acid gas ammonia-to-sulfur production equipment of the present invention: the number of low-concentration clean acid gas spray guns is 6 to 12.

[0020] As a further optimization of the low-concentration acid gas-fired ammonia-to-sulfur production equipment of the present invention: a porous fire-resistant wall is provided in the middle of the post-reaction zone.

[0021] As a further optimization of the low-concentration acidic gas-fired ammonia-to-sulfurization equipment of the present invention: the porosity of the porous refractory wall is controlled at 50%~65%.

[0022] As a further optimization of the low-concentration acid gas-fired ammonia-to-sulfurization equipment of the present invention: the opening shape of the porous refractory wall is circular, rectangular, elliptical, rhomboid or triangular.

[0023] This invention also provides a control method for the above-mentioned low-concentration acid gas ammonia-to-sulfur production equipment, comprising the following: In the complete combustion zone, the fuel gas and combustion air are controlled according to the equivalence combustion ratio set by the fuel composition, wherein the flow rate of the combustion air is adjusted proportionally according to the flow rate of the fuel gas. When a low-concentration clean acid gas is used to replace the fuel gas, the combustion air is controlled according to the equivalent combustion ratio of the low-concentration clean acid gas. The flow rate of fuel gas or low-concentration clean acid gas supplied to the complete combustion zone is adjusted according to the temperature of the pre-reaction zone. When the current reaction zone temperature is below 1250℃, increase the flow rate of fuel gas or low-concentration clean acid gas; When the current reaction zone temperature is above 1300℃, reduce the flow rate of fuel gas or low-concentration clean acid gas; The combustion air is proportionally adjusted according to the change in the flow rate of fuel gas or low-concentration clean acid gas. The low-concentration clean acid gas is divided into three parts: The first part, which accounts for no more than 10% of the total low-concentration clean acid gas, is sent as fuel to the complete combustion zone for complete combustion. The second part accounts for 60% to 80% of the total low-concentration clean acidic gas. This part is mixed with low-concentration amino acid-containing gas and then mixed with oxygen through the first acidic gas inlet component for oxygen-deficient combustion. At the same time, the flue gas generated in the oxygen-deficient combustion zone is mixed with the high-temperature flue gas generated in the complete combustion zone to maintain the temperature of the pre-reaction zone between 1250°C and 1300°C. The flow rate of combustion-supporting oxygen is adjusted according to the ratio of H2S to SO2 in the flue gas at the equipment outlet. The third part accounts for 20% to 40% of the total low-concentration clean acid gas. This part enters the area between the pre-reaction zone and the post-reaction zone through the second acid gas inlet assembly, and the flow rate of the third part of low-concentration clean acid gas is adjusted according to the temperature of the pre-reaction zone. The reaction residence time between low-concentration clean acid gas and low-concentration amino acid-containing gas in the pre-reaction zone is ≥0.8 seconds; The residence time of the low-concentration clean acid gas in the post-reaction zone of the third part is controlled to be ≥0.8 seconds.

[0024] When the current reaction zone temperature is below 1250℃, increase the flow rate of the third low-concentration clean acid gas until it reaches 40%. If the temperature of the front reaction zone is still below 1250℃, then increase the flow rate of fuel gas to increase the heat load of the first-stage complete combustion zone.

[0025] The second part, low-concentration clean acidic gas and low-concentration amino acid-containing gas, are mixed with oxygen at a ratio of 2:1 using a ratio analyzer for H2S and SO2.

[0026] The present invention has the following beneficial effects: The ammonia-to-sulfur production equipment of the present invention uses a combination of combustion air and pure oxygen as combustion aids, with zoned control of the combustion air and pure oxygen. The equipment is set up with a complete combustion zone and an oxygen-deficient combustion zone. In the complete combustion zone, the fuel gas and combustion air are completely combusted, releasing heat and producing high-temperature flue gas, which helps to increase the combustion temperature of low-concentration acidic gas. By adjusting the fuel dosage, the reaction temperature can reach above 1250℃, meeting the requirements for NH3 combustion. The oxygen-deficient combustion zone uses low-concentration clean acidic gas and low-concentration amino acid-containing gas as fuel gas, and uses pure oxygen for combustion aid, which can reduce the influence of N2 on the reaction temperature and further increase the reaction temperature. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the ammonia-to-sulfur production equipment of the present invention; Figure 2 This is a side view of the sulfur production equipment produced by burning ammonia according to the present invention. Figure 3 This is a schematic diagram of the control method for the ammonia-to-sulfur production equipment of the present invention; Marked in the image: 1. Central fuel gas inlet; 2. Central fuel gas nozzle; 3. Central low-concentration clean acid gas inlet; 4. Central low-concentration clean acid gas nozzle; 5. Oxygen inlet; 6. Combustion-supporting oxygen collection chamber; 7. Combustion-supporting oxygen nozzle; 8. First low-concentration acid gas collection chamber; 9. Low-concentration acid gas inlet; 10. Shell; 11. Refractory material layer; 12. Low-concentration acid gas cyclone separator; 13. Oxygen nozzle; 14. Complete combustion zone; 15. Central fuel nozzle. 16. Central low-concentration clean acid gas nozzle; 17. Combustion air inlet; 18. Combustion air collection chamber; 19. Ignition gun; 20. Combustion air cyclone separator; 21. Combustion air distributor; 22. Oxygen-deficient combustion zone; 23. Low-concentration clean acid gas diversion inlet; 24. Second acid gas collection chamber; 25. Low-concentration clean acid gas spray gun; 26. Rear reaction zone; 27. Porous refractory wall; 28. Furnace outlet; 29. ​​Acceleration ring; 30. Front reaction zone. Detailed Implementation

[0028] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0029] <Ammonia-to-sulfur production equipment> like Figure 1 and 2 As shown: A low-concentration acid gas ammonia-to-sulfur production equipment includes a shell 10, a central fuel gas spray gun 2, a central low-concentration clean acid gas spray gun 4, a combustion air assembly, a first acid gas inlet assembly, a combustion oxygen inlet assembly, an ignition gun 19, a speed-up ring 29, and a second acid gas inlet assembly.

[0030] The shell 10 has a complete combustion zone 14, an oxygen-deficient combustion zone 22, a pre-reaction zone 30 and a post-reaction zone 26 arranged sequentially from front to back inside, and the inner wall of the shell 10 is provided with a refractory material layer 11.

[0031] The central low-concentration clean acid gas spray gun 4 surrounds the central fuel gas spray gun 2 and is arranged coaxially with the central fuel gas spray gun 2.

[0032] The combustion air assembly includes a combustion air collection chamber 18, a combustion air distributor 21, and a combustion air cyclone separator 20. The combustion air collection chamber 18 is wrapped around the central low-concentration clean acid gas spray gun 4. The combustion air distributor 21 and the combustion air cyclone separator 20 are arranged inside the combustion air collection chamber 18 along the airflow direction.

[0033] The central fuel gas enters the central fuel gas spray gun 2 through the central fuel gas inlet 1 and is injected into the complete combustion zone 14 through the central fuel nozzle 15.

[0034] The central low-concentration clean acid gas enters the central low-concentration clean acid gas spray gun 4 through the central low-concentration clean acid gas inlet 3, and is then sprayed into the complete combustion zone 14 through the central low-concentration clean acid gas nozzle 16.

[0035] Combustion air enters the combustion air collection chamber 18 through the combustion air inlet 17, and then passes through the combustion air distributor 21 to enter the combustion air vortex 20 evenly, forming a radial swirling airflow field around the central fuel gas spray gun 2 and the central low-concentration clean acid gas spray gun 4.

[0036] In the complete combustion zone 14, the central fuel gas, the central low-concentration clean acid gas, and the swirling combustion air are uniformly mixed. The combustion air is proportioned according to the stoichiometric ratio of the fuel gas or the central low-concentration clean acid gas, ensuring the complete combustion and decomposition of the combustible components in the fuel gas and the low-concentration clean acid gas. The complete combustion zone typically uses fuel gas and air for the combustion reaction, but low-concentration clean acid gas can also be used as fuel. Hydrocarbons are converted into CO2 and H2O, and H2S in the acid gas is completely converted into SO2. Combustion generates temperatures above 1600℃, providing a stable heat source to increase the temperature of the oxygen-deficient combustion zone 22.

[0037] The first acid gas intake assembly includes a first low-concentration acid gas collection chamber 8, several acid gas nozzles, and a low-concentration acid gas cyclone separator 12. The first low-concentration acid gas collection chamber 8 surrounds the outside of the complete combustion zone 14. The several acid gas nozzles connect the first low-concentration acid gas collection chamber 8 to the oxygen-deficient combustion zone 22. The low-concentration acid gas cyclone separator 12 is arranged at the outlet of the acid gas nozzles.

[0038] The combustion oxygen intake assembly includes a combustion oxygen collection chamber 6 and several combustion oxygen spray guns 7. One end of the combustion oxygen spray gun 7 is connected to the combustion oxygen collection chamber 6, and the other end passes through the first low-concentration acid gas collection chamber 8 and the low-concentration acid gas cyclone 12 and is connected to the oxygen-deficient combustion zone 22.

[0039] The ignition gun 19 uses telescopic ignition. During ignition, its ignition end extends into the complete combustion zone 14, and after ignition, it retracts into the air header.

[0040] To reduce the amount of supplemental fuel used, the oxygen-deficient combustion zone 22 uses low-concentration clean acid gas and low-concentration amino acid-containing gas as fuel, and uses pure oxygen for combustion, which can reduce the influence of N2 on the reaction temperature and further increase the reaction temperature.

[0041] The low-concentration clean acid gas is partially diverted. 60% to 80% of the flow rate of low-concentration clean acid gas and low-concentration amino acid-containing gas enter the first low-concentration acid gas collection chamber 8 through the low-concentration acid gas inlet 9. The first low-concentration acid gas collection chamber 8 is connected to the oxygen-deficient combustion zone 22 through multiple nozzles. The nozzles are at an angle of 20° to 40° with the axis of the equipment. A low-concentration acid gas cyclone separator 12 is installed inside the nozzle. The low-concentration acid gas cyclone separator 12 is composed of multiple sets of swirling blades.

[0042] Oxygen enters the combustion oxygen collection chamber 6 through oxygen inlet 5. The combustion oxygen collection chamber 6 is divided into multiple combustion oxygen spray guns 7, preferably 4 to 8. Oxygen is injected into the secondary oxygen-deficient combustion zone 22 through oxygen nozzle 13. Oxygen is mixed with low-concentration acidic gas. The amount of oxygen is proportioned according to the H2S and SO2 content in the flue gas at the equipment outlet, typically using a ratio analyzer of 2:1 for H2S and SO2. This ratio can be adjusted appropriately to meet the needs of the downstream reactor.

[0043] Oxygen combustion is generally anoxic. Due to the low concentration of acidic gas (H2S) (less than 30%), preheating is necessary. The preheating temperature should be controlled between 150℃ and 200℃. The reaction temperature between the acidic gas and pure oxygen is typically around 1000℃. The high-temperature flue gas at 1600℃ in the complete combustion zone 14 and the flue gas at 1000℃ in the oxygen-deficient combustion zone 22 are mixed. The temperature in the pre-reaction zone 30 reaches above 1250℃. The NH3 in the low-concentration amino acid-containing gas reacts in the pre-reaction zone 30 to generate N2 and H2S.

[0044] A necking channel acceleration ring 29, composed of a refractory lining, is provided between the front reaction zone 30 and the rear reaction zone 26. The high-temperature flue gas in the front reaction zone 30 is accelerated as it passes through the acceleration ring 29.

[0045] The second acid gas intake assembly includes a low-concentration clean acid gas diversion inlet 23, a second acid gas collection chamber 24, and several low-concentration clean acid gas spray guns 25, which connect the second acid gas collection chamber 24 to the internal area of ​​the speed-up ring 29.

[0046] The low-concentration cleaning acid gas spray gun 25 is arranged in the middle of the speed-up ring 29, perpendicular to the equipment axis, which is more conducive to the uniform mixing of 20%~40% low-concentration cleaning acid gas and flue gas in the pre-reaction zone 30. The number of low-concentration cleaning acid gas spray guns 25 is preferably 6 to 12.

[0047] 20%~40% of low-concentration clean acidic gas is injected into the equipment through spray gun 25 located in the middle of the acceleration ring 29, where H2S and SO2 in the high-temperature flue gas of the pre-reaction zone 30 are further reacted in the post-reaction zone 26. 2H₂S + SO₂ → 4S + 2H₂O A porous refractory wall 27 is installed in the middle of the post-reaction zone 26. The porous refractory wall 27 is located before the furnace outlet 28. The main body of the porous refractory wall 27 is made of refractory material, and circular and rectangular openings are evenly arranged on the wall. Other shapes of openings, such as elliptical, rhomboid, and triangular, can also be used. The opening ratio is controlled at 50% to 65%.

[0048] After passing through the porous fire-resistant wall 27 set in the post-reaction zone 26, the flue gas is further mixed evenly, improving the degree of reaction and increasing the sulfur recovery rate.

[0049] <Control Methods for Ammonia-to-Sulfur Production Equipment> In the complete combustion zone 14, the fuel gas and combustion air are controlled according to the equivalent combustion ratio set by the fuel composition, wherein the flow rate of the combustion air is adjusted proportionally according to the flow rate of the fuel gas. When a low-concentration clean acid gas is used to replace the fuel gas, the combustion air is controlled according to the equivalent combustion ratio of the low-concentration clean acid gas. The flow rate of fuel gas or low-concentration clean acid gas supplied to the complete combustion zone 14 is adjusted according to the temperature of the pre-reaction zone 30. When the temperature in reaction zone 30 is below 1250℃, increase the flow rate of fuel gas or low-concentration clean acid gas. When the temperature in reaction zone 30 is above 1300℃, reduce the flow rate of fuel gas or low-concentration clean acid gas. The combustion air is proportionally adjusted according to the change in the flow rate of fuel gas or low-concentration clean acid gas. The low-concentration clean acid gas is divided into three parts: The first part, which accounts for no more than 10% of the total low-concentration clean acid gas, is sent as fuel to the complete combustion zone 14 for complete combustion. The second part accounts for 60% to 80% of the total low-concentration clean acidic gas. This part is mixed with low-concentration amino acid-containing gas and then mixed with oxygen through the first acidic gas inlet assembly for oxygen-deficient combustion. At the same time, the flue gas generated in the oxygen-deficient combustion zone 22 is mixed with the high-temperature flue gas generated in the complete combustion zone 14, so that the temperature of the pre-reaction zone 30 is maintained between 1250°C and 1300°C, and the flow rate of combustion-supporting oxygen is adjusted according to the ratio of H2S to SO2 in the flue gas at the equipment outlet. The third part accounts for 20% to 40% of the total low-concentration clean acid gas. This part enters the area between the front reaction zone 30 and the rear reaction zone 26 through the second acid gas inlet assembly, and the flow rate of the third part of low-concentration clean acid gas is adjusted according to the temperature of the front reaction zone 30. The reaction residence time of low-concentration clean acid gas and low-concentration amino acid-containing gas in the pre-reaction zone 30 is ≥0.8 seconds; The residence time of the low-concentration clean acid gas in the post-reaction zone 26 is controlled to be ≥0.8 seconds.

[0050] When the temperature of the current reaction zone 30 is below 1250℃, increase the flow rate of the low-concentration clean acid gas in the third part until it reaches 40%. If the temperature of the current reaction zone 30 is still below 1250℃, then increase the flow rate of the fuel gas to increase the heat load of the first-stage complete combustion zone 14.

[0051] The second part involves mixing low-concentration clean acidic gas with low-concentration amino acid-containing gas, and then mixing it with oxygen at a ratio of 2:1 using a ratio analyzer for H2S and SO2.

[0052] In traditional sulfur production units, the core control requirement of the Claus process is to maintain a 2:1 molar ratio of H2S to SO2 for the acid gas and combustion air, with flow control implemented. Combustion is anaerobic, where one-third of the H2S in the acid gas is oxidized to SO2, and the remaining two-thirds react with SO2 to form elemental sulfur. However, the low H2S concentration and low reaction temperature in the acid gas prevent the complete decomposition of NH3. The additional fuel gas, due to the anaerobic environment, results in incomplete combustion. Large amounts of supplemental fuel gas are ineffective in raising the reaction temperature, leading to significant conversion of fuel gas into CO and carbon black, resulting in energy waste and substandard product quality.

[0053] This invention divides the fuel and acid gas reaction zone into two regions: the fuel combustion zone is the complete reaction zone, and the acid gas reaction zone is the oxygen-deficient reaction zone of the Claus process.

[0054] The device of this invention uses a combination of combustion air and pure oxygen as combustion aids, with separate control of combustion air and pure oxygen zones. The device has a preset first-stage complete combustion zone, which utilizes the complete combustion of fuel gas and combustion air to release heat. The high-temperature flue gas produced helps to increase the combustion temperature of low-concentration acid gas. By adjusting the amount of fuel, the reaction temperature can reach above 1250°C, meeting the requirements for burning NH3.

[0055] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A low-concentration acid gas ammonia-to-sulfur production equipment, characterized in that, include: The shell has, from front to back, a complete combustion zone, an oxygen-deficient combustion zone, a pre-reaction zone, and a post-reaction zone. as well as Central fuel gas spray gun; as well as The central low-concentration clean acid gas spray gun surrounds the central fuel gas spray gun and is arranged coaxially with the central fuel gas spray gun. as well as The combustion air assembly includes a combustion air collection chamber, a combustion air distributor, and a combustion air cyclone separator. The combustion air collection chamber is wrapped around the outside of a central low-concentration clean acid gas spray gun. The combustion air distributor and the combustion air cyclone separator are arranged inside the combustion air collection chamber along the airflow direction. as well as The first acid gas intake assembly includes a first low-concentration acid gas collection chamber, a plurality of acid gas nozzles and a low-concentration acid gas cyclone separator. The first low-concentration acid gas collection chamber surrounds the outside of the complete combustion zone. The plurality of acid gas nozzles connect the first low-concentration acid gas collection chamber to the oxygen-deficient combustion zone. The low-concentration acid gas cyclone separator is arranged at the outlet of the acid gas nozzles. as well as The combustion oxygen intake assembly includes a combustion oxygen collection chamber and several combustion oxygen spray guns. One end of the combustion oxygen spray gun is connected to the combustion oxygen collection chamber, and the other end passes through the acid gas collection chamber and the acid gas cyclone separator to connect with the oxygen-deficient combustion zone. as well as A lighter, the ignition tip of which extends into the complete combustion zone; as well as The acceleration ring is positioned between the front reaction zone and the rear reaction zone; as well as The second acid gas intake assembly includes a second acid gas collection chamber and several low-concentration cleaning acid gas spray guns, which connect the second acid gas collection chamber to the internal area of ​​the speed-up ring.

2. The low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 1, characterized in that: The angle between the acid gas nozzle and the equipment axis is 20°~40°.

3. The low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 1, characterized in that: The number of the combustion-supporting oxygen spray guns is 4 to 8.

4. The low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 1, characterized in that: The number of the low-concentration cleaning acidic gas spray guns is 6 to 12.

5. The low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 1, characterized in that: A porous fire-resistant wall is provided in the middle of the post-reaction zone.

6. The low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 5, characterized in that: The porosity of the porous fire-resistant wall is controlled at 50% to 65%.

7. The low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 5, characterized in that: The openings in the porous fire-resistant wall are circular, rectangular, elliptical, rhomboid, or triangular in shape.

8. The control method for the low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 1, characterized in that, Includes the following: In the complete combustion zone, the fuel gas and combustion air are controlled according to the equivalence combustion ratio set by the fuel composition, wherein the flow rate of the combustion air is adjusted proportionally according to the flow rate of the fuel gas. When a low-concentration clean acid gas is used to replace the fuel gas, the combustion air is controlled according to the equivalent combustion ratio of the low-concentration clean acid gas. The flow rate of fuel gas or low-concentration clean acid gas supplied to the complete combustion zone is adjusted according to the temperature of the pre-reaction zone. When the current reaction zone temperature is below 1250℃, increase the flow rate of fuel gas or low-concentration clean acid gas; When the current reaction zone temperature is above 1300℃, reduce the flow rate of fuel gas or low-concentration clean acid gas; The combustion air is proportionally adjusted according to the change in the flow rate of fuel gas or low-concentration clean acid gas. The low-concentration clean acid gas is divided into three parts: The first part, which accounts for no more than 10% of the total low-concentration clean acid gas, is sent as fuel to the complete combustion zone for complete combustion. The second part accounts for 60% to 80% of the total low-concentration clean acidic gas. This part is mixed with low-concentration amino acid-containing gas and then mixed with oxygen through the first acidic gas inlet component for oxygen-deficient combustion. At the same time, the flue gas generated in the oxygen-deficient combustion zone is mixed with the high-temperature flue gas generated in the complete combustion zone to maintain the temperature of the pre-reaction zone between 1250°C and 1300°C. The flow rate of combustion-supporting oxygen is adjusted according to the ratio of H2S to SO2 in the flue gas at the equipment outlet. The third part accounts for 20% to 40% of the total low-concentration clean acid gas. This part enters the area between the pre-reaction zone and the post-reaction zone through the second acid gas inlet assembly, and the flow rate of the third part of low-concentration clean acid gas is adjusted according to the temperature of the pre-reaction zone. The reaction residence time between low-concentration clean acid gas and low-concentration amino acid-containing gas in the pre-reaction zone is ≥0.8 seconds; The residence time of the low-concentration clean acid gas in the post-reaction zone of the third part is controlled to be ≥0.8 seconds.

9. The control method for the low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 8, characterized in that: When the current reaction zone temperature is below 1250℃, increase the flow rate of the third low-concentration clean acid gas until it reaches 40%. If the temperature of the front reaction zone is still below 1250℃, then increase the flow rate of fuel gas to increase the heat load of the first-stage complete combustion zone.

10. The control method for the low-concentration acid gas ammonia-to-sulfur production equipment as described in claim 8, characterized in that: The second part, low-concentration clean acidic gas and low-concentration amino acid-containing gas, are mixed with oxygen at a ratio of 2:1 using a ratio analyzer for H2S and SO2.

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