Flue gas heat recycling system of sulfur burning furnace

Abstract

The utility model provides a flue gas heat recycling system for a sulfur burning furnace. The flue gas heat recycling system comprises an air pre-heater, the sulfur burning furnace and a cyclone separator which are sequentially communicated through a first pipeline, an air outlet of the cyclone separator is communicated with a heat exchange inlet of the air pre-heater through a first pipeline; an air inlet of the flue gas purification assembly communicates with a heat exchange outlet of the air pre-heater through a second pipeline; a heat exchange inlet and a heat exchange outlet of the heat exchanger are communicated with the second pipeline through a third pipeline and a fourth pipeline respectively, a first temperature sensor is arranged at the position, close to an air outlet of the air pre-heater, of the second pipeline, and first electromagnetic valves are arranged on the third pipeline and the position, between the third pipeline and the fourth pipeline, of the second pipeline. According to the flue gas heat recycling system, primary recycling and secondary recycling of flue gas heat of the sulfur burning furnace are achieved through the preheater and the heat exchanger, the flue gas heat of the sulfur burning furnace is recycled as much as possible, and therefore the flue gas heat recycling efficiency of the sulfur burning furnace is improved.

Description

Technical Field

[0001] The present application relates to the field of heat recovery technology, and in particular to a sulfur incinerator flue gas heat recovery and utilization system. Background Art

[0002] The sulfur incinerator is a key equipment in the sulfur acid production device. At present, the most commonly used is the spray-type sulfur incinerator, which is horizontal. Its furnace body is generally made of a steel cylinder, and the furnace body is provided with insulation bricks and refractory bricks. It has a simple structure and high volumetric strength. Specifically, sulfur is sprayed into the furnace through a spray gun, and air enters the furnace through the air inlet at the end of the furnace body. The air is fully contacted with the atomized sulfur through the swirl device for combustion. During the combustion process, sulfur produces a large amount of high-temperature flue gas, wherein the temperature of the flue gas is between 1000℃ and 1200℃. In other words, the flue gas discharged from the sulfur incinerator carries a large amount of heat. Therefore, in order to avoid the waste of heat carried by the flue gas caused by the flue gas emission in the sulfur incinerator, there is an urgent need for a flue gas heat recovery and utilization system that can be used for the sulfur incinerator, through which the heat of the flue gas in the sulfur incinerator can be recovered and utilized. Utility Model Content

[0003] The present application provides a sulfur incinerator flue gas heat recovery and utilization system to solve the technical problems described in the above background technology.

[0004] In order to solve the above technical problems, this application adopts the following technical solutions:

[0005] The present application provides a sulfur incinerator flue gas heat recovery and utilization system, comprising:

[0006] An air preheater, a sulfur incinerator and a cyclone separator are sequentially connected through a first pipeline; the gas outlet of the cyclone separator is connected to the heat exchange inlet of the air preheater through the first pipeline;

[0007] A flue gas purification component, wherein the air inlet of the flue gas purification component is connected to the heat exchange outlet of the air preheater through a second pipeline;

[0008] A heat exchanger, wherein the heat exchange inlet and the heat exchange outlet of the heat exchanger are respectively connected to the second pipe through a third pipe and a fourth pipe, the second pipe is provided with a first temperature sensor near the air outlet of the air preheater, and the third pipe and the second pipe between the third pipe and the fourth pipe are both provided with a first solenoid valve.

[0009] Optionally, the flue gas purification assembly includes a desulfurization tower and a denitrification tower connected by a fifth pipeline;

[0010] The air inlet of the desulfurization tower is connected to the end of the second pipeline away from the air preheater, the air outlet of the desulfurization tower and the air inlet of the denitrification tower are respectively connected to the two ends of the fifth pipeline, the air outlet of the denitrification tower is connected to the chimney through the induced draft duct, and the induced draft duct is provided with an induced draft fan near the chimney.

[0011] Optionally, one end of the second pipeline away from the air preheater is connected to the lower section of the desulfurization tower;

[0012] The upper section of the desulfurization tower is connected to a slurry supply tank via a sixth pipeline, and a slurry supply pump is provided on the sixth pipeline.

[0013] Optionally, the discharge port of the desulfurization tower is connected to a filtering device via a seventh pipeline, and the discharge port of the filtering device is connected to a collecting box via the seventh pipeline;

[0014] The heat exchange inlet and heat exchange outlet of the aggregate box are connected to the induced draft duct through the eighth pipe and the ninth pipe respectively. The induced draft duct is provided with a second temperature sensor near the air outlet of the denitrification tower. The eighth pipe and the induced draft duct between the eighth pipe and the ninth pipe are both provided with a second solenoid valve.

[0015] Optionally, one end of the fifth pipeline away from the desulfurization tower is connected to the lower section of the denitration tower;

[0016] The upper section of the denitration tower is connected to a mixer, an evaporator and a liquid ammonia storage tank in sequence through the tenth pipeline, and the air inlet of the mixer is connected to a denitration dilution fan through the tenth pipeline.

[0017] Optionally, the discharge port of the cyclone separator is connected to a storage bin via a discharge pipe, and a regulating valve is provided on the discharge pipe.

[0018] Optionally, the water inlet of the heat exchanger is connected to an external water source via a water supply pipe, and the hot water outlet of the heat exchanger is connected to a hot water device capable of utilizing the hot water via a water outlet pipe.

[0019] The present application provides a sulfur incinerator flue gas heat recovery and utilization system. The flue gas generated in the sulfur incinerator enters the cyclone separator and after separation by the cyclone separator, the gas (mainly sulfur dioxide and nitrogen oxides) enters the air preheater through the first pipeline and the heat exchange inlet of the air preheater to exchange heat with the air in the air preheater, causing the temperature of the above-mentioned gas to decrease and the temperature of the air to increase. The air with the increased temperature enters the sulfur incinerator, increasing the temperature in the furnace, thereby increasing the combustion rate in the sulfur incinerator, thus realizing a one-time recovery and utilization of the heat of the sulfur incinerator flue gas, and the above-mentioned gas with the reduced temperature enters the flue gas purification component through the heat exchange outlet of the air preheater and the second pipeline, and is discharged after being purified by the flue gas purification component, thereby reducing the pollution of the sulfur incinerator flue gas to the environment. In addition, the second pipe is connected to the heat exchange inlet and heat exchange outlet of the heat exchanger through the third pipe and the fourth pipe respectively, and the temperature of the gas discharged from the heat exchange outlet of the air preheater is detected by the first temperature sensor. If the temperature is higher than the preset threshold value, the first solenoid valve on the second pipe is closed and the first solenoid valve on the third pipe is opened. The gas coming out of the heat exchange outlet of the air preheater enters the heat exchanger through the second pipe, the third pipe and the heat exchange inlet of the heat exchanger, and exchanges heat with the water in the heat exchanger. The water temperature increases and the gas temperature decreases. The gas with lowered temperature enters the flue gas purification component through the heat exchange outlet of the heat exchanger, the fourth pipe and the second pipe. In other words, the secondary recovery and utilization of the flue gas heat of the sulfur incinerator is realized through the heat exchanger, so that the flue gas heat of the sulfur incinerator is recovered and utilized as much as possible, thereby improving the efficiency of recovering the flue gas heat of the sulfur incinerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A flow chart of a sulfur incinerator flue gas heat recovery and utilization system provided in one embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of a sulfur incinerator flue gas heat recovery and utilization system provided in one embodiment of the present application;

[0023] Figure 3 A schematic diagram of the structure of a sulfur incinerator flue gas heat recovery and utilization system provided in another embodiment of the present application;

[0024] Figure 4 A schematic diagram of the structure of a sulfur incinerator flue gas heat recovery and utilization system provided in another embodiment of the present application;

[0025] Figure 5 A schematic structural diagram of a sulfur incinerator flue gas heat recovery and utilization system provided in another embodiment of the present application.

[0026] In the figure: 100, air preheater; 101, first pipeline; 102, second pipeline; 1021, first temperature sensor; 103, third pipeline; 1031, first solenoid valve; 104, fourth pipeline; 105, fifth pipeline; 106, sixth pipeline; 1061, slurry supply tank; 1062, slurry supply pump; 107, seventh pipeline; 1071, filtering equipment; 1072, aggregate box; 108, eighth pipeline; 1081, second solenoid valve; 109, ninth pipeline; 200, sulfur incinerator; 300, cyclone separation device; 400, flue gas purification component; 401, desulfurization tower; 402, denitrification tower; 500, heat exchanger; 501, water supply pipeline; 5011, external water source; 502, water outlet pipeline; 5021, hot water equipment; 600, induced draft duct; 601, chimney; 602, induced draft fan; 603, second temperature sensor; 700, tenth pipeline; 701, mixer; 702, evaporator; 703, liquid ammonia storage tank; 704, denitrification dilution fan; 800, discharge pipe; 801, storage bin; 802, regulating valve. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0028] refer to Figures 1 to 5 The present application provides a sulfur incinerator flue gas heat recovery system, comprising:

[0029] The air preheater 100, the sulfur incinerator 200 and the cyclone separator 300 are connected in sequence through the first pipeline 101; the air outlet of the cyclone separator 300 is connected with the heat exchange inlet of the air preheater 100 through the first pipeline 101; wherein, since a certain amount of oxygen is required during the combustion of sulfur in the sulfur incinerator 200, air enters the air preheater 100 through the air inlet on the air preheater 100 and exchanges heat with the heat exchange medium (the heat exchange medium here refers to the flue gas discharged from the sulfur incinerator 200 in this application) entering the air preheater 100 from the heat exchange inlet on the air preheater 100, thereby improving the combustion efficiency of sulfur in the sulfur incinerator 200. The flue gas generated by the combustion of sulfur in the sulfur incinerator 200 contains not only gases such as sulfur dioxide and nitrogen oxides, but also carries some particulate matter (such as sulfate particulate matter such as potassium sulfate, ammonium sulfate, and carbon black, etc.). The flue gas coming out of the sulfur incinerator 200 is separated into gas and solid by the cyclone separator 300, and the particulate matter contained in the above flue gas is separated from the gas, so as to avoid clogging of pipes and other devices by the particulate matter contained in the flue gas during subsequent treatment. That is, the setting of the cyclone separator 300 improves the flow efficiency of the flue gas during the treatment process.

[0030] The flue gas purification component 400, the air inlet of the flue gas purification component 400 is connected to the heat exchange outlet of the air preheater 100 through the second pipe 102; since the flue gas discharged from the sulfur incinerator 200 not only contains a large amount of heat, but also contains harmful gases such as sulfur dioxide and nitrogen oxides, if the heat is used to discharge it directly, the harmful gases such as sulfur dioxide and nitrogen oxides in it will pollute the environment, for example: sulfur dioxide and nitrogen oxides will form sulfuric acid and nitric acid respectively when they meet water, causing acid rain. In addition, nitrogen oxides can react with other pollutants (such as volatile organic compounds and particulate matter) to generate ozone and fine particulate matter, thereby adversely affecting air quality. Therefore, in the present application, the flue gas whose temperature is reduced after heat exchange with the air in the air preheater 100 enters the flue gas purification component 400 from the heat exchange outlet of the air preheater 100, and the harmful gases such as sulfur dioxide and nitrogen oxides in the flue gas are removed by the flue gas purification component 400, thereby reducing the harm of the flue gas to the environment.

[0031] The heat exchanger 500, the heat exchange inlet and the heat exchange outlet of the heat exchanger 500 are connected to the second pipeline 102 through the third pipeline 103 and the fourth pipeline 104 respectively, the second pipeline 102 is provided with a first temperature sensor 1021 near the air outlet of the air preheater 100, and the third pipeline 103 and the second pipeline 102 between the third pipeline 103 and the fourth pipeline 104 are both provided with a first solenoid valve 1031. Among them, the temperature of the gas discharged from the heat exchange outlet of the air preheater 100 is detected by the first temperature sensor 1021. If the temperature is higher than a preset threshold value (the preset threshold value can be set according to actual conditions, and this application does not specifically limit it here), the first solenoid valve 1031 on the second pipe 102 is closed and the first solenoid valve 1031 on the third pipe 103 is opened. The gas coming out of the heat exchange outlet of the air preheater 100 enters the heat exchanger 500 through the second pipe 102, the third pipe 103 and the heat exchange inlet of the heat exchanger 500, and exchanges heat with the water in the heat exchanger 500. The water temperature increases and the gas temperature decreases. The gas with reduced temperature enters the flue gas purification component 400 through the heat exchange outlet of the heat exchanger 500, the fourth pipe 104 and the second pipe 102. That is to say, the secondary recovery and utilization of the flue gas heat of the sulfur incinerator 200 is realized through the heat exchanger 500, so that the flue gas heat of the sulfur incinerator 200 is recovered and utilized as much as possible, thereby improving the efficiency of flue gas heat recovery and utilization of the sulfur incinerator 200.

[0032] The present application provides a sulfur incinerator flue gas heat recovery and utilization system. The flue gas generated in the sulfur incinerator 200 enters the cyclone separator 300. After separation by the cyclone separator 300, the gas (mainly sulfur dioxide and nitrogen oxides) enters the air preheater 100 through the first pipeline 101 and the heat exchange inlet of the air preheater 100 to exchange heat with the air in the air preheater 100, causing the temperature of the above-mentioned gas to decrease and the temperature of the air to increase. The air with increased temperature enters the sulfur incinerator 200, increasing the temperature in the furnace, thereby increasing the combustion rate in the sulfur incinerator 200, thereby realizing a one-time recovery and utilization of the heat of the flue gas of the sulfur incinerator 200. The above-mentioned gas with reduced temperature enters the flue gas purification component 400 through the heat exchange outlet of the air preheater 100 and the second pipeline 102, and is discharged after being purified by the flue gas purification component 400, thereby reducing the pollution of the flue gas of the sulfur incinerator 200 to the environment. In addition, the second pipeline 102 is connected to the heat exchange inlet and the heat exchange outlet of the heat exchanger 500 through the third pipeline 103 and the fourth pipeline 104, respectively. The temperature of the gas discharged from the heat exchange outlet of the air preheater 100 is detected by the first temperature sensor 1021. If the temperature is higher than the preset threshold, the first solenoid valve 1031 on the second pipeline 102 is closed and the first solenoid valve 1031 on the third pipeline 103 is opened. The gas coming out of the heat exchange outlet of the air preheater 100 passes through the second pipeline 102, the third pipeline 103 and the heat exchanger 500. 00 enters the heat exchanger 500 through the heat exchange inlet and exchanges heat with the water in the heat exchanger 500. The water temperature increases and the gas temperature decreases. The gas after the temperature is reduced enters the flue gas purification component 400 through the heat exchange outlet of the heat exchanger 500, the fourth pipe 104 and the second pipe 102. In other words, the heat exchanger 500 is used to realize the secondary recovery and utilization of the flue gas heat of the sulfur incinerator 200, so that the flue gas heat of the sulfur incinerator 200 is recovered and utilized as much as possible, thereby improving the efficiency of recovering the flue gas heat of the sulfur incinerator 200.

[0033] In some embodiments, reference Figure 3 The flue gas purification component 400 in the present application includes a desulfurization tower 401 and a denitrification tower 402 connected through a fifth pipe 105; specifically, the air inlet of the desulfurization tower 401 is connected to the end of the second pipe 102 away from the air preheater 100, the air outlet of the desulfurization tower 401 and the air inlet of the denitrification tower 402 are respectively connected to the two ends of the fifth pipe 105, and the air outlet of the denitrification tower 402 is connected to the chimney 601 through the induced draft duct 600, and the induced draft fan 602 is arranged near the chimney 601 in the induced draft duct 600.

[0034] In the above embodiment, the flue gas recycled once by the air preheater 100 or recycled twice by the heat exchanger 500 enters the desulfurization tower 401 through the second pipeline 102 and the air inlet of the desulfurization tower 401, and the flue gas desulfurized by the desulfurization tower 401 enters the denitrification tower 402 from the air outlet of the desulfurization tower 401, the fifth pipeline 105 and the air inlet of the denitrification tower 402, and the flue gas is denitrated by the denitrification tower 402, and the flue gas after denitrification is discharged from the air outlet of the denitrification tower 402, the induced draft duct 600 and the chimney 601, that is, the present application processes sulfur dioxide and nitrogen oxides in the flue gas through the desulfurization tower 401 and the denitrification tower 402, thereby realizing harmless emission of the flue gas. In addition, the setting of the induced draft fan 602 speeds up the circulation speed of the flue gas and improves the circulation and treatment efficiency of the flue gas.

[0035] In some embodiments, reference Figure 3 In the present application, the end of the second pipeline 102 away from the air preheater 100 is connected to the lower section of the desulfurization tower 401; that is, the flue gas in the sulfur incinerator 200 enters the desulfurization tower 401 from the lower section of the desulfurization tower 401 after the primary heat exchange in the air preheater 100 or the secondary heat exchange in the heat exchanger 500 and diffuses to the upper section of the desulfurization tower 401.

[0036] The upper section of the desulfurization tower 401 is connected to a slurry supply tank 1061 through a sixth pipeline 106, and a slurry supply pump 1062 is provided on the sixth pipeline 106. The slurry supply tank 1061 is filled with limestone slurry, and the limestone slurry in the slurry supply tank 1061 enters the desulfurization tower 401 through the sixth pipeline 106 under the power provided by the slurry supply pump 1062 and flows from top to bottom in the desulfurization tower 401, and then contacts the flue gas diffused from bottom to top in the desulfurization tower 401, thereby removing sulfur dioxide in the flue gas and generating calcium sulfate, thereby removing sulfur dioxide in the flue gas after heat exchange.

[0037] In some embodiments, reference Figure 3 The discharge port of the desulfurization tower 401 in the present application is connected to a filter device 1071 through a seventh pipeline 107, and the discharge port of the filter device 1071 is connected to a collection box 1072 through the seventh pipeline 107; wherein, the limestone slurry that has not fully reacted with the sulfur dioxide in the flue gas and the calcium sulfate generated after the reaction with the sulfur dioxide both enter the filter device 1071 from the discharge port of the desulfurization tower 401 and the seventh pipeline 107, and the filter device 1071 filters the water in the mixture of the above-mentioned limestone slurry and calcium sulfate and transports the filtered solid matter to the collection box 1072 through the seventh pipeline 107.

[0038] The heat exchange inlet and the heat exchange outlet of the aggregate box 1072 are connected to the induced draft duct 600 through the eighth pipe 108 and the ninth pipe 109 respectively. The induced draft duct 600 is provided with a second temperature sensor 603 near the air outlet of the denitrification tower 402. The eighth pipe 108 and the induced draft duct 600 between the eighth pipe 108 and the ninth pipe 109 are both provided with a second solenoid valve 1081. The temperature of the flue gas after denitration treatment by the denitrification tower 402 is detected by the second temperature sensor 603. If the temperature of the flue gas is greater than a preset temperature (set according to actual conditions, and the present application does not further define it here), the second solenoid valve 1081 on the eighth pipe 108 is opened and the second solenoid valve 1081 on the induced draft duct 600 is closed, and the denitrated flue gas is then introduced into the aggregate box 1072 through the eighth pipe 108 and the heat exchange inlet of the aggregate box 1072 to exchange heat with the solid matter in the aggregate box 1072 ( The dehydrated limestone and calcium sulfate) are dried in the aggregate box 1072 to facilitate the subsequent use of the solid matter after recovery (for example, the recovered limestone can be used to prepare limestone slurry for flue gas desulfurization treatment again), and avoid the use of additional heat to heat the solid matter, saving heat. At the same time, the heat of the flue gas is recycled and utilized three times, which improves the efficiency of flue gas heat recovery and utilization. The temperature of the flue gas after heat exchange with the solid matter is reduced and discharged through the ninth pipeline 109, the induced draft duct 600 and the chimney 601. On the contrary, if the temperature of the flue gas after denitration detected by the second temperature sensor 603 is lower than the preset temperature, the flue gas after denitration is directly discharged through the induced draft duct 600 and the chimney 601.

[0039] In some embodiments, reference Figure 4 The end of the fifth pipeline 105 in the present application away from the desulfurization tower 401 is connected to the lower section of the denitrification tower 402; the flue gas desulfurized by the desulfurization tower 401 enters the denitrification tower 402 from the lower section of the denitrification tower 402 and diffuses from bottom to top in the denitrification tower 402.

[0040] The upper section of the denitrification tower 402 is connected to the mixer 701, the evaporator 702 and the liquid ammonia storage tank 703 in sequence through the tenth pipeline 700, and the air inlet of the mixer 701 is connected to the denitrification dilution fan 704 through the tenth pipeline 700. Among them, the liquid ammonia storage tank 703 is filled with liquid ammonia, and the liquid ammonia is converted into ammonia gas under the action of the evaporator 702 and enters the mixer 701 to mix with the air entering the mixer 701 from the tenth pipeline 700. The mixed gas after the two are mixed enters the denitrification tower 402 and reacts with the flue gas after desulfurization entering the denitrification tower 402, so that the nitrogen oxides are converted into nitrogen. The function of the denitrification dilution fan 704 is to blow a large amount of air to dilute the ammonia gas to a certain proportion and then spray it into the denitrification tower 402, so as to ensure the smooth progress of the denitrification reaction in the denitrification tower 402.

[0041] In some embodiments, reference Figure 5 The discharge port of the cyclone separator 300 in the present application is connected to a storage bin 801 through a discharge pipe 800 , and a regulating valve 802 is provided on the discharge pipe 800 .

[0042] In the above embodiment, the regulating valve 802 is opened at regular intervals so that the particulate matter in the flue gas separated by the cyclone separator 300 enters the storage bin 801 through the discharge pipe, thereby collecting the particulate matter in the flue gas through the storage bin 801, avoiding the accumulation of particulate matter in the cyclone separator 300 and affecting the separation of the cyclone separator 300, thereby ensuring the separation efficiency of the cyclone separator 300.

[0043] In some embodiments, reference 2 to Figure 5 The water inlet of the heat exchanger 500 in the present application is connected to an external water source 5011 through a water supply pipe 501, and the hot water outlet of the heat exchanger 500 is connected to a hot water device 5021 that can use hot water through a water outlet pipe 502. Among them, the hot water device 5021 can be a floor heating, a hot water storage tank, etc., which depends on the needs in the actual application process. Therefore, this application does not specifically limit it here. In other words, the heat exchanger 500 can not only recycle the flue gas discharged by the sulfur incinerator 200 for secondary use, but also generate hot water for the hot water device 5021, thereby meeting the daily needs of factories and the like for hot water.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A sulfur incinerator flue gas heat recovery and utilization system, characterized in that: include: An air preheater (100), a sulfur incinerator (200) and a cyclone separator (300) are sequentially connected via a first pipeline (101); an air outlet of the cyclone separator (300) is connected to a heat exchange inlet of the air preheater (100) via the first pipeline (101); A flue gas purification component (400), wherein an air inlet of the flue gas purification component (400) is connected to a heat exchange outlet of the air preheater (100) via a second pipe (102); A heat exchanger (500), wherein a heat exchange inlet and a heat exchange outlet of the heat exchanger (500) are respectively connected to the second pipe (102) through a third pipe (103) and a fourth pipe (104), a first temperature sensor (1021) is provided on the second pipe (102) near the air outlet of the air preheater (100), and a first solenoid valve (1031) is provided on the third pipe (103) and the second pipe (102) between the third pipe (103) and the fourth pipe (104).

2. The sulfur incinerator flue gas heat recovery and utilization system according to claim 1 is characterized in that: The flue gas purification component (400) comprises a desulfurization tower (401) and a denitrification tower (402) which are connected via a fifth pipeline (105); The air inlet of the desulfurization tower (401) is connected to an end of the second pipeline (102) away from the air preheater (100), the air outlet of the desulfurization tower (401) and the air inlet of the denitrification tower (402) are respectively connected to the two ends of the fifth pipeline (105), the air outlet of the denitrification tower (402) is connected to the chimney (601) through the induced draft duct (600), and the induced draft fan (602) is arranged on the induced draft duct (600) near the chimney (601).

3. The sulfur incinerator flue gas heat recovery and utilization system according to claim 2 is characterized in that: One end of the second pipeline (102) away from the air preheater (100) is connected to the lower section of the desulfurization tower (401); The upper section of the desulfurization tower (401) is connected to a slurry supply tank (1061) via a sixth pipeline (106), and a slurry supply pump (1062) is provided on the sixth pipeline (106).

4. The sulfur incinerator flue gas heat recovery and utilization system according to claim 3 is characterized in that: The discharge port of the desulfurization tower (401) is connected to a filter device (1071) via a seventh pipeline (107), and the discharge port of the filter device (1071) is connected to a collection box (1072) via the seventh pipeline (107); The heat exchange inlet and the heat exchange outlet of the collecting box (1072) are connected to the induced draft duct (600) through the eighth pipe (108) and the ninth pipe (109) respectively. The induced draft duct (600) is provided with a second temperature sensor (603) near the air outlet of the denitrification tower (402). The eighth pipe (108) and the induced draft duct (600) between the eighth pipe (108) and the ninth pipe (109) are both provided with a second solenoid valve (1081).

5. The sulfur incinerator flue gas heat recovery and utilization system according to claim 2 is characterized in that: One end of the fifth pipeline (105) away from the desulfurization tower (401) is connected to the lower section of the denitration tower (402); The upper section of the denitration tower (402) is connected in sequence to a mixer (701), an evaporator (702) and a liquid ammonia storage tank (703) via a tenth pipeline (700), and the air inlet of the mixer (701) is connected to a denitration dilution fan (704) via the tenth pipeline (700).

6. The sulfur incinerator flue gas heat recovery and utilization system according to claim 1, characterized in that: The discharge port of the cyclone separator (300) is connected to a storage bin (801) via a discharge pipe (800), and a regulating valve (802) is provided on the discharge pipe (800).

7. The sulfur incinerator flue gas heat recovery and utilization system according to any one of claims 1 to 6, characterized in that: The water inlet of the heat exchanger (500) is connected to an external water source (5011) via a water supply pipe (501), and the hot water outlet of the heat exchanger (500) is connected to a hot water device (5021) capable of utilizing the hot water via a water outlet pipe (502).

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