Process and equipment for preparing liquid sulfur dioxide through pure oxygen incineration

Abstract

The invention relates to the technical field of chemical raw material preparation, and discloses a process and equipment for preparing liquid sulfur dioxide through pure oxygen incineration, the system deeply couples dynamic optimization of three high-energy-consumption links of waste heat recovery, combustion reaction and deep freezing through hardware collaboration and algorithm innovation, and compared with a traditional process, the comprehensive energy consumption of unit products is reduced by 35%, and the production cost is reduced. Meanwhile, the three technical problems of liquid sulfur solidification, furnace temperature out-of-control and non-condensable gas accumulation are solved.

Description

Technical Field

[0001] The present application relates to the technical field of chemical raw material preparation, and more particularly to a process and equipment for producing liquid sulfur dioxide by incineration of pure oxygen. Background Art

[0002] Liquid sulfur dioxide is a key raw material for the production of chemical products such as sulfuric acid, sulfites, and thiosulfates. Existing equipment typically produces liquid sulfur dioxide by burning sulfur to produce sulfur dioxide gas, which is then cooled to liquefy.

[0003] Existing equipment uses liquid sulfur dioxide, a key raw material for the production of chemical products such as sulfuric acid and sulfites, for industrial production, typically employing a sulfur incineration-flue gas purification-cryogenic liquefaction process. This mainstream process generates high-temperature SO2 flue gas (>900°C) by burning molten sulfur with pure oxygen. This flue gas is then cooled in a waste heat boiler, dust-removed, pickled, and demisted, before being deep-cooled to below -10°C in a cryogenic liquefier to produce a liquid product.

[0004] However, this process has the following significant drawbacks:

[0005] 1. Severely insufficient waste heat recovery: The high-grade heat energy (900-1100°C) generated by the incinerator is only partially recovered as medium-temperature steam (approximately 200-300°C) via the waste heat boiler. However, the heating of the molten sulfur tank (120-150°C) and the insulation of the pipelines (>130°C) required to maintain the flow of liquid sulfur still rely on external steam or electric heating, resulting in a double waste of energy. Field measurements show that in traditional processes, as much as 35%-40% of the incineration heat is directly discharged as low-temperature flue gas.

[0006] 2. Excessive energy consumption during refrigeration and liquefaction: The liquefaction of gaseous SO2 requires the release of a large amount of latent heat. Existing equipment generally uses a crude mode of directly freezing to -25°C (with a subcooling degree of more than 15°C). This does not dynamically optimize the refrigeration temperature based on the actual composition of the flue gas (SO2 concentration fluctuates by 10% to 15%), resulting in an increase of more than 30% in inefficient compressor power consumption. More seriously, over-refrigeration still cannot completely prevent the accumulation of non-condensable gases (O2, N2, etc.) in the liquefier, requiring regular shutdown for exhaust, reducing the efficiency of continuous operation.

[0007] 3. Poor operating stability:

[0008] Due to the lack of precise temperature control (especially when the ambient temperature is <5°C), the liquid sulfur transportation pipeline often becomes clogged due to sulfur solidification, forcing production to be interrupted.

[0009] The oxygen-sulfur ratio control of the incinerator relies on manual experience. Oxygen concentration fluctuations of ±2% result in furnace temperature jumps of >±50°C, which not only accelerates the loss of refractory materials but also causes the SO2 conversion rate to drop to 95% to 97%;

[0010] There is no early warning mechanism for scaling failure of equipment such as pickling towers and heat exchangers, and the frequency of sudden failure shutdowns reaches 0.5 times per month.

[0011] In summary, the existing technology has high production costs for liquid sulfur dioxide due to the broken energy cascade utilization, extensive freezing process, and lagging control strategy, and the system reliability is difficult to meet the requirements of continuous production. Burning sulfur will generate a lot of heat. The temperature of the incinerator can reach over 900°C. The flue gas needs to drop to -10°C or below for the gaseous sulfur dioxide to become liquid. Therefore, the heat that needs to be released is very large, and the solid sulfur needs to be melted in the sulfur melting tank to form liquid sulfur to be sprayed into the incinerator to be fully mixed with oxygen for combustion. The existing technology does not have a waste heat recovery device designed to recover the waste heat of the incineration flue gas to melt the solid sulfur and keep the sulfur in liquid form, resulting in energy waste. Summary of the Invention

[0012] This application provides a process and equipment for producing liquid sulfur dioxide by incineration of pure oxygen, aiming to address the deficiencies of the existing technology.

[0013] In one scheme, the equipment for producing liquid sulfur dioxide by incineration of pure oxygen includes:

[0014] a sulfur melting tank for melting solid sulfur, a filter for filtering liquid sulfur, a liquid sulfur storage tank connected to the filter, an incinerator connected to the liquid sulfur storage tank, a waste heat boiler connected to the incinerator, a dust collector connected to the waste heat boiler, a first pickling tower connected to the dust collector, a second pickling tower connected to the first pickling tower, a demister connected to the second pickling tower, a regenerator connected to the demister, a sulfur dioxide refrigeration liquefaction device connected to the regenerator, a transfer tank connected to the sulfur dioxide refrigeration liquefaction device, a liquid sulfur dioxide storage tank connected to the regenerator, and a waste heat recovery device;

[0015] a sulfur melting tank for melting solid sulfur, a filter for filtering liquid sulfur, a liquid sulfur storage tank connected to the filter, an incinerator connected to the liquid sulfur storage tank, a waste heat boiler connected to the incinerator, a dust collector connected to the waste heat boiler, a first pickling tower connected to the dust collector, a second pickling tower connected to the first pickling tower, a demister connected to the second pickling tower, a regenerator connected to the demister, a sulfur dioxide refrigeration liquefaction device connected to the regenerator, a transfer tank connected to the sulfur dioxide refrigeration liquefaction device, a liquid sulfur dioxide storage tank connected to the regenerator, and a waste heat recovery device;

[0016] include:

[0017] a sulfur melting tank for melting solid sulfur, a filter for filtering liquid sulfur, a liquid sulfur storage tank connected to the filter, an incinerator connected to the liquid sulfur storage tank, a waste heat boiler connected to the incinerator, a dust collector connected to the waste heat boiler, a first pickling tower connected to the dust collector, a second pickling tower connected to the first pickling tower, a demister connected to the second pickling tower, a regenerator connected to the demister, a sulfur dioxide refrigeration liquefaction device connected to the regenerator, a transfer tank connected to the sulfur dioxide refrigeration liquefaction device, a liquid sulfur dioxide storage tank connected to the regenerator, and a waste heat recovery device;

[0018] include:

[0019] Sensor set, including:

[0020] A first temperature sensor and a first flow meter are provided at the outlet of the incinerator;

[0021] a second temperature sensor disposed in the sulfur melting tank;

[0022] a third temperature sensor disposed between the filter and the liquid sulfur storage tank;

[0023] A sulfur flow meter is provided on the outlet pipe of the liquid sulfur storage tank;

[0024] An oxygen flow meter is provided on the oxygen supply pipe;

[0025] A SO2 concentration analyzer is provided at the outlet of the demister;

[0026] a fourth temperature sensor provided at the outlet of the refrigerated liquefier;

[0027] The control module is in communication with the sensor group and executes:

[0028] (1) Waste heat dynamic allocation algorithm:

[0029] Calculate the available waste heat \(Q_{avail}=k_1\cdot(T_{gas}T_{env})\cdot Q_{gas}\) based on the flue gas temperature \(T_{gas}\) and flow \(Q_{gas}\) at the incinerator outlet;

[0030] When the temperature in the sulfur melting tank is T_{melt}<120°C, a first control signal is generated to increase the heat medium flow from the waste heat recovery device to the heating section of the sulfur melting tank;

[0031] When the filter outlet temperature is T<130°C, a second control signal is generated to increase the flow of heat medium to the heating section of the filter outer wall.

[0032] (2) Freezing liquefaction optimization algorithm:

[0033] Calculate the theoretical liquefaction temperature (T_{liquefy}=f(C_{SO2},P_{in})\) based on the SO2 concentration \(C_{SO2}\) and the demister outlet temperature \(T_{in}\);

[0034] Set the target temperature of the refrigerated liquefier outlet (T_{set}=T_{liquefy}10℃\) to no less than -25℃;

[0035] Adjust the refrigeration compressor frequency so that the measured temperature at the outlet of the refrigeration liquefier reaches \(T_{set}\);

[0036] Based on the transfer tank temperature \(T_{buffer}\) and the regenerator cold side inlet temperature \(T_{cold-in}\), the hot side flow ratio \(R=k_2\cdot(T_{cold-in}(-10℃)) / (T_{buffer}T_{cold-in})\) is calculated to control the bypass valve opening;

[0037] (3) Combustion control algorithm:

[0038] Calculate the theoretical oxygen content (Q_{O2-base}=Q_{sulfur}\times 1.0\) according to the reaction formula \(S+O_2\rightarrow SO_2\);

[0039] When the temperature in the incinerator is \(T_{furnace}>950℃\), the output oxygen correction instruction \(Q_{O2-adj}=Q_{O2-base}\times[10.05\times(T_{furnace}950)]\);

[0040] When the O2 concentration in the flue gas is \(C_{O2}>3\%\), the oxygen amount is gradually reduced until \(C_{O2}=1.5\%\);

[0041] The implementing agency group includes:

[0042] A proportional control valve provided at the inlet of each heating section of the waste heat recovery device responds to the first and second control signals;

[0043] The inverter connected to the refrigeration liquefier compressor responds to the temperature setting command;

[0044] The electric regulating valve installed on the oxygen supply pipe responds to the oxygen correction instruction.

[0045] Further, in the cryogenic liquefaction optimization algorithm, when it is detected that the pressure in the cryogenic liquefier continues to rise and the temperature fluctuation > 2°C / min, the non-condensable gas discharge valve is triggered to open, and the opening duration \(t = k_3\cdot\Delta P\), where \(\Delta P\) is the pressure deviation value.

[0046] Further, the waste heat dynamic distribution algorithm further includes:

[0047] Calculate the minimum maintenance heat load of the liquid sulfur pipeline \(Q_{maintain}=k_4\cdot(T_{set - maintain}-T_{env})\), where \(T_{set - maintain}=135°C\);

[0048] If \(Q_{avail}<Q_{maintain}\), an alarm signal is generated and the electric heater in the sulfur melting tank is started.

[0049] Further, the control module executes a fouling warning algorithm:

[0050] Obtain the flue gas temperature \(T_{in - boiler}\) at the inlet of the waste heat boiler and the water temperature \(T_{out - water}\) at the outlet;

[0051] When the actual heat exchange amount \(Q_{act}<0.9\times Q_{design}\), an instruction to clean the waste heat boiler (5) is generated and the fouling coefficient \(R_f = 1-\frac{Q_{act}}{U\cdot A\cdot\Delta T_{lm}}\) is calculated.

[0052] Further, in the combustion control algorithm, the liquid sulfur atomization pressure \(P_{spray}\) is dynamically adjusted according to the sulfur flow rate \(Q_{sulfur}\):

[0053] \[P_{spray}=P_{min}+k_5\cdot(Q_{sulfur}-Q_{sulfur - min})\]

[0054] where \(P_{min}=0.3MPa\) is the minimum atomization pressure.

[0055] Further, the cryogenic liquefaction optimization algorithm adopts model predictive control (MPC), including:

[0056] Based on historical data, establish a flue gas load change model \(Q_{gas}(t)=f(t,\alpha)\);

[0057] Rolling optimization is performed on the next 15-minute refrigeration compressor frequency sequence \([F_1,F_2,...,F_n]\) to satisfy the \(T_{set}\) constraint and minimize the total energy consumption \(\sum(F_i^2\cdot\Delta t)\).

[0058] On the other hand, the present application also provides a process for producing liquid sulfur dioxide by incineration of pure oxygen, comprising the following steps:

[0059] a) monitoring the sulfur temperature in the sulfur melting tank in real time by the second temperature sensor, and when T_{melt} < 120°C, increasing the flow of heat medium from the waste heat recovery device to the sulfur melting tank;

[0060] b) dynamically setting the outlet temperature of the refrigerated liquefier (10) to \(T_{liquefy}10°C\) based on the data from the SO2 concentration analyzer and the fourth temperature sensor;

[0061] c) When the incinerator thermocouple detects that \(T_{furnace}>950℃\), the oxygen supply is reduced according to \(Q_{O2-adj}=Q_{O2-base}\times[10.05\times(T_{furnace}950)]\). Beneficial effects of this application:

[0062] 1. Significantly reduced energy consumption: waste heat utilization rate increased to >90% (conventional process <70%), and external heat supply for molten sulfur was reduced by 40%. The refrigeration system's power consumption was reduced by 25% due to the dynamic setting of subcooling (-10°C) and heat recovery optimization.

[0063] 2. Enhanced operational stability: Closed-loop control of the liquid sulfur pipeline temperature (maintained ≥135°C) completely eliminates solidification and blockage; adaptive adjustment of the oxygen-sulfur ratio narrows the furnace temperature fluctuation range from ±50°C to ±15°C, and the sulfur conversion rate is stabilized at above 99.2%.

[0064] 3. Extended equipment life: The fouling early warning model uses the fouling coefficient \(R_f=1-\frac{Q_{act}}{U\cdotA\cdot\Delta T_{lm}}\) to identify heat exchanger efficiency degradation 30% of the life cycle in advance, and the pressure difference monitoring of the pickling tower reduces the risk of sudden shutdown by 50%.

[0065] 4. Breakthrough in intelligence: Model predictive control (MPC) optimizes the refrigeration compressor frequency sequence in a 15-minute rolling manner, increasing the response speed to load fluctuations by three times; the non-condensable gas discharge strategy (triggered when pressure rise + temperature fluctuation > 2°C / min) enables liquefaction purity to reach 99.99%.

[0066] In summary, the system deeply couples the dynamic optimization of three high-energy-consuming links: waste heat recovery, combustion reaction, and deep freezing, through hardware collaboration and algorithm innovation. Compared with traditional processes, the comprehensive energy consumption per unit product is reduced by 35%, while solving the three major technical pain points of liquid sulfur solidification, furnace temperature out of control, and non-condensable gas accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0068] Figure 1 This is a schematic diagram of a process for producing sulfur dioxide in one embodiment of the present application;

[0069] Reference numerals in the figures:

[0070] 1. Sulfur melting tank; 2. Filter; 3. Liquid sulfur storage tank; 4. Incinerator; 5. Waste heat boiler; 6. Dust collector; 7. First pickling tower; 8. Second pickling tower; 9. Demister; 10. Sulfur dioxide refrigeration liquefaction device; 17. Transfer tank; 18. Regenerator; 56. Liquid sulfur dioxide storage tank. DETAILED DESCRIPTION

[0071] The specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application and not all embodiments. All other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0072] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0073] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0074] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0075] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0076] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0077] In some embodiments, referring to the accompanying drawings, a device for producing liquid sulfur dioxide by incineration of pure oxygen is provided, comprising:

[0078] a sulfur melting tank 1 for melting solid sulfur, a filter 2 for filtering liquid sulfur, a liquid sulfur storage tank 3 connected to the filter 2, an incinerator 4 connected to the liquid sulfur storage tank 3, a waste heat boiler 5 connected to the incinerator 4, a dust collector 6 connected to the waste heat boiler 5, a first acid washing tower 7 connected to the dust collector 6, a second acid washing tower 8 connected to the first acid washing tower 7, a demister 9 connected to the second acid washing tower 8, a regenerator 18 connected to the demister 9, a sulfur dioxide refrigeration liquefier 10 connected to the regenerator 18, a transfer tank 17 connected to the sulfur dioxide refrigeration liquefier 10, a liquid sulfur dioxide storage tank 56 connected to the regenerator 18, and a waste heat recovery device;

[0079] include:

[0080] Sensor set, including:

[0081] A first temperature sensor and a first flow meter are provided at the outlet of the incinerator 4;

[0082] A second temperature sensor is provided in the sulfur melting tank 1;

[0083] A third temperature sensor is provided between the filter 2 and the liquid sulfur storage tank 3;

[0084] A sulfur flow meter is provided at the outlet pipe of the liquid sulfur storage tank 3;

[0085] An oxygen flow meter is provided on the oxygen supply pipe;

[0086] A SO2 concentration analyzer is provided at the outlet of the demister 9;

[0087] A fourth temperature sensor is provided at the outlet of the refrigerated liquefier 10;

[0088] The control module is in communication with the sensor group and executes:

[0089] (1) Waste heat dynamic allocation algorithm:

[0090] Calculate the available waste heat (Q_{avail}=k_1\cdot(T_{gas}T_{env})\cdot Q_{gas}\) based on the flue gas temperature \(T_{gas}\) and flow \(Q_{gas}\) at the outlet of incinerator 4;

[0091] When the temperature in the sulfur melting tank 1 is \(T_{melt}<120°C\), a first control signal is generated to increase the flow of heat medium from the waste heat recovery device to the heating section of the sulfur melting tank 1;

[0092] When the outlet temperature of filter 2 is \(T_{filter}<130℃\), a second control signal is generated to increase the flow of heat medium to the heating section of the outer wall of filter 2;

[0093] The available waste heat is calculated based on the formula \(Q_{avail}=k_1\cdot(T_{gas}T_{env})\cdot Q_{gas}\). When the temperature of the molten sulfur tank is less than 120℃, the heat medium flow in the heating section is increased. When the filter outlet temperature is less than 130℃, the insulation heat distribution is prioritized. If the waste heat is insufficient, the electric heater is started and an alarm is sounded.

[0094] (2) Freezing liquefaction optimization algorithm:

[0095] Calculate the theoretical liquefaction temperature (T_{liquefy}=f(C_{SO2},P_{in})\) based on the SO2 concentration \(C_{SO2}\) and the demister 9 outlet temperature \(T_{in}\);

[0096] Set the target outlet temperature of the refrigerated liquefier 10 (T_{set}=T_{liquefy}10℃\) to no less than -25℃;

[0097] Adjust the refrigeration compressor frequency to achieve the measured temperature at the outlet of the refrigerated liquefier 10, Tset. Calculate the hot-side flow ratio, R = k2(Tcold-in(-10°C)) / (TbufferTcold-in), based on the transfer tank 17 temperature, Tbuffer, and the cold-side inlet temperature, Tcold-in, of the regenerator 18 to control the bypass valve opening.

[0098] The theoretical liquefaction temperature \(T_{liquefy}\) is calculated based on the SO2 concentration and inlet pressure, and the target outlet temperature of the refrigerated liquefier \(T_{set}=T_{liquefy}10℃\) (limited to -25℃) is dynamically set. The compressor frequency is adjusted by the inverter to achieve precise temperature control; simultaneously, the regenerator bypass valve is adjusted based on the formula \(R=k_2\cdot(T_{col d-in}+10) / (T_{buffer}T_{cold-in})\) to stabilize the mixed liquid SO2 at below -10℃.

[0099] (3) Combustion control algorithm:

[0100] Calculate the theoretical oxygen content (Q_{O2-base}=Q_{sulfur}\times 1.0\) according to the reaction formula \(S+O_2\rightarrow SO_2\);

[0101] When the temperature in the incinerator 4 is \(T_{furnace}>950℃\), the oxygen amount correction instruction \(Q_{O2-adj}=Q_{O2-base}\times[10.05\times(T_{furnace}950)]\) is output;

[0102] When the O2 concentration in the flue gas is \(C_{O2}>3\%\), the oxygen amount is gradually reduced until \(C_{O2}=1.5\%\);

[0103] The implementing agency group includes:

[0104] A proportional control valve provided at the inlet of each heating section of the waste heat recovery device responds to the first and second control signals;

[0105] The frequency converter connected to the compressor of the refrigeration liquefier 10 responds to the temperature setting instruction;

[0106] The electric regulating valve installed on the oxygen supply pipe responds to the oxygen correction instruction.

[0107] The basic oxygen content is calculated according to the stoichiometric ratio \(Q_{O2-base}=Q_{sulfur}\times 1.0\). When the furnace temperature is greater than 950℃, the oxygen is dynamically reduced and the temperature is suppressed according to \(Q_{O2-adj}=Q_{O2-base}\times[10.05\times(T_{fu rnace}950)]\). When the O2 concentration in the flue gas is greater than 3%, the oxygen valve is adjusted in a closed loop until the concentration drops to 1.5%.

[0108] The actuator group (proportional control valve, frequency converter, electric oxygen valve) converts the algorithm instructions into physical actions, forming a "perception-decision-execution" closed loop.

[0109] Furthermore, in the refrigeration liquefaction optimization algorithm, when it is detected that the pressure in the refrigeration liquefier 10 continues to rise and the temperature fluctuation is greater than 2°C / min, the non-condensable gas discharge valve is triggered to open, and the opening time is \(t=k_3\cdot\Delta P\), where \(\Delta P\) is the pressure deviation value.

[0110] In one embodiment of the present application, the waste heat dynamic allocation algorithm further includes:

[0111] Calculate the minimum maintenance heat load of the liquid sulfur pipeline \(Q_{maintain}=k_4\cdot(T_{set-maintai n}T_{env})\), where \(T_{set-maintain}=135℃\);

[0112] If \(Q_{avail}<Q_{maintain}\), an alarm signal is generated and the electric heater in the sulfur melting tank 1 is started.

[0113] In an embodiment of the present application, the control module executes a fouling warning algorithm:

[0114] Obtain the flue gas temperature \(T_{in - boiler}\) at the inlet of the waste heat boiler 5 and the water temperature \(T_{out - water}\) at the outlet.

[0115] When the actual heat transfer quantity \(Q_{act}<0.9\times Q_{design}\), an instruction to clean the waste heat boiler (5) is generated and the fouling coefficient \(R_f = 1\frac{Q_{act}}{U\cdot A\cdot\Delta T_{lm}}\) is calculated.

[0116] In an embodiment of the present application, in the combustion control algorithm, the liquid sulfur atomization pressure \(P_{spray}\) is dynamically adjusted according to the sulfur flow rate \(Q_{sulfur}\):

[0117] \[P_{spray}=P_{min}+k_5\cdot(Q_{sulfur}-Q_{sulfur - min})\]

[0118] Where \(P_{min}=0.3MPa\) is the minimum atomization pressure.

[0119] In an embodiment of the present application, the refrigeration liquefaction optimization algorithm adopts model predictive control (MPC), including:

[0120] Establish a flue gas load change model \(Q_{gas}(t)=f(t,\alpha)\) based on historical data;

[0121] Rolling optimize the future 15 - minute refrigeration compressor frequency sequence \([F_1,F_2,...,F_n]\) to meet the \(T_{set}\) constraint and minimize the total energy consumption \(\sum(F_i^2\cdot\Delta t)\).

[0122] In an embodiment of the present application, a process for producing liquid sulfur dioxide by pure oxygen incineration is also provided, including the following steps:

[0123] a) Real - time monitor the sulfur temperature in the sulfur melting tank by the second temperature sensor. When \(T_{melt}<120℃\), increase the heat medium flow rate from the waste heat recovery device to the sulfur melting tank 1.

[0124] b) dynamically setting the outlet temperature of the refrigerated liquefier 10 to T_{liquefy}10°C based on data from the SO2 concentration analyzer and the fourth temperature sensor;

[0125] c) When the thermocouple of incinerator 4 detects \(T_{furnace}>950℃\), the oxygen supply is reduced according to \(Q_{O2-adj}=Q_{O2-base}\times[10.05\times(T_{furnace}950)]\).

[0126] Test Example 1

[0127] 1. Test conditions

[0128] Test Subject:

[0129] Control group: Traditional liquid sulfur incineration freezing process (no waste heat recovery for molten sulfur, fixed freezing temperature of -25°C, manual adjustment of oxygen-sulfur ratio)

[0130] Experimental group: Equipment of the same scale using the intelligent optimization control system of the present invention

[0131] Raw material parameters: solid sulfur purity ≥99.5%, oxygen purity ≥99.2%

[0132] Environmental parameters: ambient temperature 5°C, relative humidity 60%

[0133] Test duration: 720 hours (30 days) of continuous operation

[0134] 2. Key performance comparison

[0135]

[0136]

[0137] 3. Comparison of typical working conditions (taking a 20% sudden change in incinerator load as an example)

[0138] Control group:

[0139] The oxygen adjustment was delayed for 8 minutes, the furnace temperature rose sharply to 1015°C (for 15 minutes), and the instantaneous SO2 conversion rate dropped to 89%.

[0140] Due to flue gas temperature fluctuations, the refrigeration system's compressor started and stopped frequently three times, with peak power consumption reaching 150% of the rated value.

[0141] Experimental group:

[0142] The combustion control algorithm completes oxygen correction within 45 seconds, and the furnace temperature is stabilized at 940±10℃

[0143] The MPC model predicts load changes, and the compressor frequency is smoothly adjusted, so the power consumption is always below 95% of the rated value.

[0144] Test conclusion

[0145] Quantification of energy-saving benefits: The experimental group reduced external heating for molten sulfur by 85% through a dynamic waste heat allocation algorithm, and combined with adaptive freezing temperature settings, reduced power consumption by 27.1%, and the comprehensive energy consumption cost per ton of product decreased by 41.5%.

[0146] Reliability breakthrough: Closed-loop temperature control of the liquid sulfur pipeline completely eliminates solidification blockage, and the scaling early warning model identifies waste heat boiler efficiency degradation 24 hours in advance (triggering cleaning when the measured fouling coefficient Rf>0.25), achieving 720 hours of zero unplanned downtime.

[0147] Improved product quality: The intelligent non-condensable gas emission strategy (based on a pressure-temperature coupling model) enables liquid SO2 purity to exceed 99.97%, with a total impurity level of <300ppm, meeting electronic-grade chemical standards.

[0148] The above are merely optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application. Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may make changes, modifications, replacements, and variations to the above embodiments within the scope of the present invention.

Claims

1. Equipment for producing liquid sulfur dioxide by incineration of pure oxygen, including: a sulfur melting tank for melting solid sulfur, a filter for filtering liquid sulfur, a liquid sulfur storage tank connected to the filter, an incinerator connected to the liquid sulfur storage tank, a waste heat boiler connected to the incinerator, a dust collector connected to the waste heat boiler, a first pickling tower connected to the dust collector, a second pickling tower connected to the first pickling tower, a demister connected to the second pickling tower, a regenerator connected to the demister, a sulfur dioxide refrigeration liquefaction device connected to the regenerator, a transfer tank connected to the sulfur dioxide refrigeration liquefaction device, a liquid sulfur dioxide storage tank connected to the regenerator, and a waste heat recovery device; The invention is characterized by comprising: Sensor set, including: A first temperature sensor and a first flow meter are provided at the outlet of the incinerator; a second temperature sensor disposed in the sulfur melting tank; a third temperature sensor disposed between the filter and the liquid sulfur storage tank; A sulfur flow meter is provided on the outlet pipe of the liquid sulfur storage tank; An oxygen flow meter is provided on the oxygen supply pipe; A SO2 concentration analyzer is provided at the outlet of the demister; a fourth temperature sensor provided at the outlet of the refrigerated liquefier; The control module is in communication with the sensor group and executes: (1) Waste heat dynamic allocation algorithm: Calculate the available waste heat \(Q_{avail}=k_1\cdot(T_{gas}T_{env})\cdot Q_{gas}\) based on the flue gas temperature \(T_{gas}\) and flow \(Q_{gas}\) at the incinerator outlet; When the temperature in the sulfur melting tank is T_{melt}<120°C, a first control signal is generated to increase the heat medium flow from the waste heat recovery device to the heating section of the sulfur melting tank; When the filter outlet temperature is T<130°C, a second control signal is generated to increase the flow of heat medium to the heating section of the filter outer wall. (2) Freezing liquefaction optimization algorithm: Calculate the theoretical liquefaction temperature (T_{liquefy}=f(C_{SO2},P_{in})\) based on the SO2 concentration \(C_{SO2}\) and the demister outlet temperature \(T_{in}\); Set the target temperature of the refrigerated liquefier outlet (T_{set}=T_{liquefy}10℃\) to no less than -25℃; Adjust the refrigeration compressor frequency so that the measured temperature at the outlet of the refrigeration liquefier reaches \(T_{set}\); Based on the transfer tank temperature \(T_{buffer}\) and the regenerator cold side inlet temperature \(T_{cold-in}\), the hot side flow ratio \(R=k_2\cdot(T_{cold-in}(-10℃)) / (T_{buffer}T_{cold-in})\) is calculated to control the bypass valve opening; (3) Combustion control algorithm: Calculate the theoretical oxygen content (Q_{O2-base}=Q_{sulfur}\times 1.0\) according to the reaction formula \(S+O_2\rightarrow SO_2\); When the temperature in the incinerator \(T_{furnace}>950^{\circ}C\), the output oxygen amount correction instruction \(Q_{O2 - adj}=Q_{O2 - base}\times[10.05\times(T_{furnace}-950)]\); When the O2 concentration in the flue gas \(C_{O2}>3\%\), gradually reduce the oxygen amount until \(C_{O2}=1.5\%\); Actuator group, including: Proportional regulating valves set at the inlets of each heating section of the waste heat recovery device, responding to the first and second control signals; Frequency converters connected to the compressors of the refrigerated liquefiers, responding to the temperature setting instruction; Electric regulating valves set on the oxygen supply pipe, responding to the oxygen amount correction instruction.

2. The device according to claim 1, wherein: In the refrigerated liquefaction optimization algorithm, when it is detected that the pressure in the refrigerated liquefier continuously rises and the temperature fluctuation > 2°C / min, trigger the opening of the non-condensable gas discharge valve, and the opening duration \(t = k_3\cdot\Delta P\), where \(\Delta P\) is the pressure deviation value.

3. The device according to claim 1, wherein: The waste heat dynamic distribution algorithm further includes: Calculate the minimum maintenance heat load of the liquid sulfur pipeline \(Q_{maintain}=k_4\cdot(T_{set - maintain}-T_{env})\), where \(T_{set - maintain}=135^{\circ}C\); If \(Q_{avail}<Q_{maintain}\), generate an alarm signal and start the electric heater in the sulfur melting tank.

4. The device according to claim 1, wherein: The control module executes the fouling warning algorithm: Obtain the flue gas temperature \(T_{in - boiler}\) at the inlet of the waste heat boiler and the outlet water temperature \(T_{out - water}\); When the actual heat transfer amount \(Q_{act}<0.9\times Q_{design}\), generate an instruction to clean the waste heat boiler and calculate the fouling coefficient \(R_f = 1-\frac{Q_{act}}{U\cdot A\cdot\Delta T_{lm}}\).

5. The device according to claim 1, wherein: In the combustion control algorithm, the liquid sulfur atomization pressure \(P_{spray}\) is dynamically adjusted according to the sulfur flow rate \(Q_{sulfur}\): \[P_{spray}=P_{min}+k_5\cdot(Q_{sulfur}-Q_{sulfur - min})\] where \(P_{min}=0.3MPa\) is the minimum atomization pressure.

6. The device according to claim 1, wherein: The refrigerated liquefaction optimization algorithm adopts model predictive control (MPC), including: Establish a flue gas load change model \(Q_{gas}(t)=f(t,\alpha)\) based on historical data; Rolling optimization is performed on the next 15-minute refrigeration compressor frequency sequence \([F_1,F_2,...,F_n]\) to satisfy the \(T_{set}\) constraint and minimize the total energy consumption \(\sum(F_i^2\cdot\Delta t)\).

7. A process for preparing liquid sulfur dioxide using the apparatus according to any one of claims 1 to 6, characterized in that: include: a) monitoring the sulfur temperature in the sulfur melting tank in real time by the second temperature sensor, and when T_{melt} < 120°C, increasing the flow of heat medium from the waste heat recovery device to the sulfur melting tank; b) dynamically setting the outlet temperature of the refrigerated liquefier (10) to \(T_{liquefy}10°C\) based on the data from the SO2 concentration analyzer and the fourth temperature sensor; c) When the incinerator thermocouple detects \(T_{furnace}>950℃\), reduce the oxygen supply according to \(Q_{O2-adj}=Q_{O2-base}\times[10.05\times(T_{furnace}950)]\).

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