Tail gas recovery process for producing insoluble sulfur by high-temperature liquid sulfur atomization direct method

Abstract

The invention relates to a tail gas recovery process for producing insoluble sulfur by a high-temperature liquid sulfur atomization direct method, which comprises the following steps: S1, carrying out quenching granulation on high-temperature tail gas through a quenching tower, atomizing liquid sulfur into liquid drops with the particle size of 50-200mu m by using an atomizing nozzle, directly contacting the liquid sulfur with the high-temperature tail gas, and quickly condensing into spherical sulfur particles, and controlling the cooling rate to be 103-104 DEG C / s through low-temperature circulating oil or liquid carbon dioxide, inhibiting particle aggregation, and obtaining the monodisperse sulfur microspheres. Modified white oil or dimethyl silicone oil is adopted as an absorbent, and spraying of an alkaline solution is combined, so that deep purification of harmful substances such as sulfur steam, sulfur dioxide and hydrogen sulfide is realized, and the monodisperse sulfur microspheres are obtained. The tail gas recovery rate reaches up to 95% or above, meanwhile, the recovered sulfur particles and byproducts can be recycled, the resource utilization rate is increased, particle size regulation and morphology optimization of the sulfur particles are synchronously achieved in the tail gas recovery process, and spherical or regular-shaped sulfur particles meeting the high-end market requirement can be produced.

Description

Technical Field

[0001] The present invention relates to the field of tail gas recovery, in particular to a tail gas recovery process for producing insoluble sulfur by a high-temperature liquid sulfur atomization direct method. Background Art

[0002] Currently, the direct process of producing insoluble sulfur by high-temperature liquid sulfur atomization has gradually been adopted in the industry. This process mainly involves heating liquid sulfur at high temperatures, using atomization technology to disperse it into tiny droplets, and then generating insoluble sulfur through a polymerization reaction.

[0003] While existing technologies have achieved some success, they still have some significant shortcomings. First, there are deficiencies in tail gas treatment. The tail gas produced during the high-temperature liquid sulfur atomization process contains harmful substances such as sulfur vapor, sulfur dioxide, and hydrogen sulfide. If discharged directly without effective treatment, it will pollute the environment. Furthermore, existing processes have a low recovery rate for sulfur resources in tail gas, resulting in a waste of resources. Second, the morphology and particle size of sulfur particles cannot be precisely controlled. Traditional production processes often only produce sulfur particles with uneven particle size distribution and irregular shapes, which cannot meet the demand for regularly shaped sulfur particles in the high-end market. Furthermore, existing processes still rely on manual experience in parameter control and process optimization, making it difficult to achieve intelligent control and optimize resource recycling.

[0004] Therefore, we proposed a tail gas recovery process for the direct production of insoluble sulfur by high-temperature liquid sulfur atomization. By integrating tail gas recovery with sulfur particle shaping technology, clean and efficient production was achieved. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and meet the actual needs. It provides a tail gas recovery process for the direct production of insoluble sulfur by high-temperature liquid sulfur atomization to solve the current problems. First, there are deficiencies in tail gas treatment. The tail gas generated during the high-temperature liquid sulfur atomization process contains harmful substances such as sulfur vapor, sulfur dioxide, and hydrogen sulfide. If it is directly discharged without effective treatment, it will pollute the environment. Moreover, the existing process has a low recovery rate of sulfur resources in the tail gas, resulting in a waste of resources. Secondly, the morphology and particle size control of the sulfur particles are not precise enough. Traditional production processes often can only produce sulfur particles with uneven particle size distribution and irregular shape, which is difficult to meet the demand of the high-end market for regularly shaped sulfur particles. At the same time, the existing process still relies on manual experience in parameter control and process optimization, making it difficult to achieve intelligent control and optimization of resource recycling.

[0006] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is to design a tail gas recovery process for producing insoluble sulfur by direct method of high-temperature liquid sulfur atomization, comprising the following steps:

[0007] S1, the high temperature tail gas is rapidly cooled and granulated by a quenching tower, and the liquid sulfur is atomized into droplets with a particle size of 50-200 μm by an atomizing nozzle. After direct contact with the high temperature tail gas, it is quickly condensed into spherical sulfur particles, and the cooling rate is controlled by low temperature circulating oil or liquid carbon dioxide at 10 3 -10 4 ℃ / s, inhibiting particle agglomeration and obtaining monodisperse sulfur microspheres;

[0008] S2. Passing the quenched tail gas into a rotating packed bed for multi-stage absorption, using a composite absorbent system to separate sulfur vapor, sulfur dioxide and hydrogen sulfide, wherein the main absorbent is modified white oil or dimethyl silicone oil, and the auxiliary absorbent is an alkaline solution;

[0009] S3, through the ceramic fiber filter tube dust collector and wet electrostatic precipitator to carry out two-stage dust removal on the tail gas, so that the dust content of the tail gas is less than 10mg / m 3 ;

[0010] S4. Feeding the recovered sulfur particles into a fluidized bed to achieve particle size growth through collision and adhesion of the sulfur particles, controlling the temperature to 120-150° C., using nitrogen as the fluidizing gas, adding 0.1-0.5 wt % of stearic acid, adjusting the fluidizing velocity to 0.5-2 m / s and the residence time to 10-30 min, to prepare regular sulfur particles with a particle size of 0.1-2 mm;

[0011] S5. The recovered sulfur is melted, filtered, degassed and purified, and then returned to the liquid sulfur storage tank for recycling. A digital model of the entire tail gas treatment process is established to simulate changes in parameters such as temperature, pressure, and flow in real time, predict absorbent consumption and sulfur recovery rate, and guide process optimization.

[0012] Preferably, the quenching tower integrates an atomizing nozzle and a low-temperature spraying device, and recovers the waste heat of the tail gas before quenching through a heat exchanger to preheat the liquid sulfur in the liquid sulfur storage tank.

[0013] Preferably, the rotating packed bed has a rotation speed of 500-1500 rpm, a gas-liquid volume ratio of 1:10-1:50, and the alkaline solution is NaOH or ammonia water with a concentration of 5-10 wt%.

[0014] Preferably, a surfactant is added to the composite absorbent system to enhance the absorption efficiency of sulfur vapor, and the amount of surfactant added is 0.05-0.2 wt%.

[0015] Preferably, the fluidized bed is equipped with a particle size analyzer, and the fluidization speed, temperature and additive dosage are automatically adjusted by PLC to ensure that the standard deviation of the sulfur particle size distribution is ≤15%.

[0016] Preferably, the digital model collects tail gas temperature, sulfur vapor concentration and particle size data in real time through online monitoring equipment, and uses an algorithm to dynamically adjust the quench tower water temperature, RPB speed and fluidized bed temperature.

[0017] Preferably, the sulfite / sulfide in the alkaline absorption liquid is converted into sodium thiosulfate or ammonium sulfate by-products through oxidation and crystallization processes, thereby realizing resource utilization.

[0018] Preferably, in the quenching granulation step, the aperture of the liquid sulfur atomizing nozzle is 0.1-0.5 mm, and the atomizing pressure is 0.3-0.8 MPa.

[0019] Preferably, the operating voltage of the wet electrostatic precipitator is 20-50 kV, the plate spacing is 10-30 mm, and the capture efficiency of fine particles with a particle size of 0.1-5 μm is ensured to be ≥99%.

[0020] Preferably, the process further comprises a melt-extrusion granulation step: the recovered sulfur particles are melted at 160-180° C., extruded through a porous die and cut into cylindrical particles with a particle size of 2-5 mm, and then rapidly solidified by water cooling or air cooling.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention utilizes modified white oil (with added surfactant) or dimethyl silicone oil to improve the solubility of sulfur vapor and organic sulfides by targeting the process characteristics of direct production of insoluble sulfur through high-temperature liquid sulfur atomization. An alkaline solution (such as NaOH or aqueous ammonia) is sprayed in the second section of the absorption tower to neutralize acidic gases such as SO2 and H2S, generating recyclable sulfites / sulfides. Multi-stage treatment achieves deep purification of harmful substances such as sulfur vapor, sulfur dioxide, and hydrogen sulfide, achieving a tail gas recovery rate of over 95%. Furthermore, the recovered sulfur particles can be directly returned to the production process, and by-products such as sulfites and sulfides can also be recycled, thereby improving resource utilization.

[0023] 2. The present invention can produce spherical or regularly shaped sulfur particles (particle size 0.1-5 mm) by simultaneously achieving particle size control and morphology optimization of sulfur particles during the tail gas recovery process, meeting the needs of the high-end market.

[0024] 3. The present invention establishes a digital model and uses online monitoring equipment (such as an infrared spectrometer and a particle size analyzer) to collect data such as tail gas temperature, composition, and particle size in real time. Based on the collected data, the absorbent consumption, sulfur recovery rate, and particle morphology are predicted. Parameters such as the quench tower water temperature, the rotating packed bed speed, and the fluidized bed temperature are automatically adjusted according to the algorithm to ensure that the system always operates in the optimal operating condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0027] A tail gas recovery process for producing insoluble sulfur by direct high-temperature liquid sulfur atomization method, see Figure 1 , including the following steps:

[0028] S1, the high temperature tail gas is rapidly cooled and granulated by a quenching tower, and the liquid sulfur is atomized into droplets with a particle size of 50-200 μm by an atomizing nozzle. After direct contact with the high temperature tail gas, it is quickly condensed into spherical sulfur particles, and the cooling rate is controlled by low temperature circulating oil or liquid carbon dioxide at 10 3 -10 4 ℃ / s, inhibiting particle agglomeration and obtaining monodisperse sulfur microspheres;

[0029] S2. Passing the quenched tail gas into a rotating packed bed for multi-stage absorption, using a composite absorbent system to separate sulfur vapor, sulfur dioxide and hydrogen sulfide, wherein the main absorbent is modified white oil or dimethyl silicone oil, and the auxiliary absorbent is an alkaline solution;

[0030] S3, through the ceramic fiber filter tube dust collector and wet electrostatic precipitator to carry out two-stage dust removal on the tail gas, so that the dust content of the tail gas is less than 10mg / m 3 ;

[0031] S4. Feeding the recovered sulfur particles into a fluidized bed to achieve particle size growth through collision and adhesion of the sulfur particles, controlling the temperature to 120-150° C., using nitrogen as the fluidizing gas, adding 0.1-0.5 wt % of stearic acid, adjusting the fluidizing velocity to 0.5-2 m / s and the residence time to 10-30 min, to prepare regular sulfur particles with a particle size of 0.1-2 mm;

[0032] S5. The recovered sulfur is melted, filtered, degassed and purified, and then returned to the liquid sulfur storage tank for recycling. A digital model of the entire tail gas treatment process is established to simulate changes in parameters such as temperature, pressure, and flow in real time, predict absorbent consumption and sulfur recovery rate, and guide process optimization.

[0033] For details, see Figure 1 The quenching tower integrates atomizing nozzles and low-temperature spraying equipment, and recovers the waste heat of the tail gas before quenching through a heat exchanger to preheat the liquid sulfur in the liquid sulfur storage tank.

[0034] For more details, see Figure 1 The rotating packed bed has a rotation speed of 500-1500 rpm, a gas-liquid volume ratio of 1:10-1:50, and the alkaline solution is NaOH or ammonia water with a concentration of 5-10 wt%.

[0035] For further information, see Figure 1 A surfactant is added to the composite absorbent system to enhance the absorption efficiency of sulfur vapor, and the amount of surfactant added is 0.05-0.2wt%.

[0036] Further, see Figure 1 The fluidized bed is equipped with a particle size analyzer, and the fluidization speed, temperature and additive dosage are automatically adjusted by PLC to ensure that the standard deviation of the sulfur particle size distribution is ≤15%.

[0037] It is worth noting that, see Figure 1 The digital model collects real-time data on tail gas temperature, sulfur vapor concentration and particle size through online monitoring equipment, and uses algorithms to dynamically adjust the quench tower water temperature, RPB speed and fluidized bed temperature.

[0038] It is worth noting that see Figure 1 The sulfite / sulfide in the alkaline absorption liquid is converted into sodium thiosulfate or ammonium sulfate by-products through oxidation and crystallization processes, realizing resource utilization.

[0039] It is worth mentioning that see Figure 1 In the rapid cooling and granulation step, the aperture of the liquid sulfur atomizing nozzle is 0.1-0.5 mm, and the atomizing pressure is 0.3-0.8 MPa.

[0040] It is worth noting that, see Figure 1 The operating voltage of the wet electrostatic precipitator is 20-50kV, the plate spacing is 10-30mm, and the capture efficiency of fine particles with a particle size of 0.1-5μm is ensured to be ≥99%.

[0041] It is worth emphasizing that see Figure 1 The process also includes a melt-extrusion granulation step: the recovered sulfur particles are melted at 160-180°C, extruded through a porous die and cut into cylindrical particles with a particle size of 2-5 mm, and then quickly solidified by water cooling or air cooling.

[0042] Example 1

[0043] Tail gas recovery process optimization based on digital model and adaptive algorithm

[0044] Technical parameters:

[0045] Data collection: equipped with infrared spectrometer (to monitor sulfur vapor concentration), particle size analyzer (to detect sulfur particle size in real time), and temperature sensor (exhaust gas temperature).

[0046] Digital model construction: Establish a digital twin system for the entire exhaust gas treatment process, including the physical models and mass transfer kinetic equations of the quench tower, rotating packed bed (RPB), and fluidized bed.

[0047] Algorithm design: Adopting adaptive control algorithm based on machine learning (random forest algorithm), the input parameters include exhaust temperature (400-500℃), sulfur vapor concentration (0.5-2.0g / m 3 ), particle size (0.1-5μm), the output parameters are quench tower water temperature (20-50℃), RPB speed (500-1500rpm), and fluidized bed temperature (120-150℃).

[0048] Implementation results: Through real-time optimization, sulfur recovery rate increased from 92% to 97%, particle size standard deviation decreased from 20% to 12%, and energy consumption decreased by 15%.

[0049] Example 2

[0050] Integrated process of rapid cooling granulation and waste heat recovery

[0051] Technical parameters:

[0052] Configuration of the quenching tower: atomizing nozzle aperture 0.3mm, atomizing pressure 0.5MPa, liquid sulfur atomized droplet size 100μm.

[0053] Waste heat recovery: The heat exchanger is used to recover the waste heat (450°C) of the tail gas before quenching, preheating the liquid sulfur storage tank temperature to 160°C, reducing natural gas consumption by 10%.

[0054] Cooling medium: liquid carbon dioxide, cooling rate 5×10 3 ℃ / s, monodisperse sulfur microspheres (particle size 0.5 mm) were generated.

[0055] Implementation effect: Dust content in exhaust gas is reduced to 8mg / m 3 , the sphericity of sulfur particles is >90%.

[0056] Example 3

[0057] Composite absorbent system and by-product resource utilization

[0058] Technical parameters:

[0059] Main absorbent: modified white oil (added with 0.1 wt% sodium dodecylbenzene sulfonate), the sulfur vapor absorption efficiency is increased to 95%.

[0060] Auxiliary absorbent: 8wt% NaOH solution, neutralizes SO2 and H2S to generate Na2SO3 (recovery rate 85%).

[0061] By-product treatment: Oxidation of Na2SO3 to Na2S2O3 (sodium thiosulfate), purity ≥ 98%.

[0062] Implementation effect: SO2 concentration in tail gas <30mg / m 3, the annual income from by-products increased by 500,000 yuan.

[0063] Example 4

[0064] Melt-extrusion granulation to produce high-end sulfur granules

[0065] Technical parameters:

[0066] Melting unit: temperature 170℃, molten sulfur is extruded into strips through a screw extruder (die head aperture 3mm).

[0067] Cutting and curing: Cut into cylindrical particles (particle size 3mm) and water-cool to room temperature.

[0068] Product performance: Particle compressive strength ≥50N / cm 2 , meeting the high-end demand for rubber vulcanizers.

[0069] Implementation effect: product premium of 12%, annual sales increased by 2 million yuan.

[0070] Comparative Example 1

[0071] Traditional electric heating exhaust gas treatment process

[0072] Technical parameters:

[0073] Heating method: Electric heating (energy consumption 1200kWh / ton of sulfur), no waste heat recovery.

[0074] Exhaust gas treatment: Only bag dust collector is used, and the dust content of exhaust gas is >50mg / m 3 , SO2 concentration>100mg / m 3 .

[0075] Sulfur particles: uneven particle size distribution (0.1-10mm), sphericity <60%.

[0076] Comparison of results: The sulfur recovery rate is only 85%, energy consumption is high, and environmental pollution is serious.

[0077] Comparative Example 2

[0078] Fluidized bed granulation process without intelligent control

[0079] Technical parameters:

[0080] Fluidized bed parameters: manual adjustment of temperature (fluctuation ±20°C), fluidization velocity (0.3-2.5 m / s).

[0081] Particle quality: particle size standard deviation>25%, particle adhesion rate>15%.

[0082] Waste of resources: The sulfur recycling rate is only 80%, and by-products are not recovered.

[0083] Comparison of results: Compared with Example 1, the product qualification rate decreased by 30% and the cost increased by 18%. The specific comparative data are as follows:

[0084]

[0085]

[0086] In summary, Example 1 highlights the optimization effect of intelligent control on the process; Comparative Examples 1 and 2 are compared with traditional processes from the perspectives of energy consumption, pollution, and stability, respectively, highlighting the advanced nature of the technology of the present invention.

[0087] In addition, the components designed in the present invention are all universal standard parts or components known to those skilled in the art. Their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods. They can be fully implemented by those skilled in the art. Needless to say, the content protected by the present invention does not involve improvements to internal structures and methods.

[0088] The embodiments disclosed in the present invention are preferred embodiments, but are not limited to them. Ordinary technicians in this field can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. As long as they do not deviate from the spirit of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A tail gas recovery process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur, characterized in that: The following steps are involved: S1, the high temperature tail gas is rapidly cooled and granulated by a quenching tower, and the liquid sulfur is atomized into droplets with a particle size of 50-200 μm by an atomizing nozzle. After direct contact with the high temperature tail gas, it is quickly condensed into spherical sulfur particles, and the cooling rate is controlled by low temperature circulating oil or liquid carbon dioxide at 10 3 -10 4 ℃ / s, inhibiting particle agglomeration and obtaining monodisperse sulfur microspheres; S2. Passing the quenched tail gas into a rotating packed bed for multi-stage absorption, using a composite absorbent system to separate sulfur vapor, sulfur dioxide and hydrogen sulfide, wherein the main absorbent is modified white oil or dimethyl silicone oil, and the auxiliary absorbent is an alkaline solution; S3, the tail gas is subjected to two-stage dust removal through ceramic fiber filter tube dust collector and wet electrostatic precipitator, so that the dust content of the tail gas is less than 10mg / m 3 ; S4. Feeding the recovered sulfur particles into a fluidized bed to achieve particle size growth through collision and adhesion of the sulfur particles, controlling the temperature to 120-150° C., using nitrogen as the fluidizing gas, adding 0.1-0.5 wt % of stearic acid, adjusting the fluidizing velocity to 0.5-2 m / s and the residence time to 10-30 min, to prepare regular sulfur particles with a particle size of 0.1-2 mm; S5. The recovered sulfur is melted, filtered, degassed and purified, and then returned to the liquid sulfur storage tank for recycling. A digital model of the entire tail gas treatment process is established to simulate changes in parameters such as temperature, pressure, and flow in real time, predict absorbent consumption and sulfur recovery rate, and guide process optimization.

2. The tail gas recovery process according to claim 1, characterized in that: The quenching tower integrates an atomizing nozzle and a low-temperature spraying device, and recovers the waste heat of the tail gas before quenching through a heat exchanger to preheat the liquid sulfur in the liquid sulfur storage tank.

3. The tail gas recovery process according to claim 1, characterized in that: The rotating packed bed has a rotation speed of 500-1500 rpm, a gas-liquid volume ratio of 1:10-1:50, and the alkaline solution is NaOH or ammonia water with a concentration of 5-10 wt%.

4. The tail gas recovery process according to claim 1, characterized in that: A surfactant is added to the composite absorbent system to enhance the absorption efficiency of sulfur vapor. The amount of surfactant added is 0.05-0.2 wt%.

5. The tail gas recovery process according to claim 1, characterized in that: The fluidized bed is equipped with a particle size analyzer, and the fluidization speed, temperature and additive dosage are automatically adjusted by PLC to ensure that the standard deviation of the sulfur particle size distribution is ≤15%.

6. The tail gas recovery process according to claim 1, characterized in that: The digital model collects tail gas temperature, sulfur vapor concentration and particle size data in real time through online monitoring equipment, and uses algorithms to dynamically adjust the quench tower water temperature, RPB speed and fluidized bed temperature.

7. The tail gas recovery process according to claim 1, characterized in that: The sulfite / sulfide in the alkaline absorption liquid is converted into sodium thiosulfate or ammonium sulfate by-products through oxidation and crystallization processes, thereby realizing resource utilization.

8. The tail gas recovery process according to claim 1, characterized in that: In the quenching granulation step, the aperture of the liquid sulfur atomizing nozzle is 0.1-0.5 mm, and the atomizing pressure is 0.3-0.8 MPa.

9. The tail gas recovery process according to claim 1, characterized in that: The wet electrostatic precipitator has an operating voltage of 20-50 kV and an electrode plate spacing of 10-30 mm, ensuring a capture efficiency of fine particles with a particle size of 0.1-5 μm of ≥99%.

10. The tail gas recovery process according to claim 1, characterized in that: The process also includes a melt-extrusion granulation step: the recovered sulfur particles are melted at 160-180° C., extruded through a porous die head and cut into cylindrical particles with a particle size of 2-5 mm, and then rapidly solidified by water cooling or air cooling.

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