Waste heat steam boiler based on integration of sulfur combustion furnace and nitrogen heat extraction

Abstract

The utility model discloses a waste heat steam boiler based on integration of a sulfur combustion furnace and nitrogen heat extraction, and belongs to the technical field of salt chemical engineering and waste heat recovery. In order to solve the problem of waste of waste heat of high-temperature SO2 flue gas in the SO2 preparation process of the sulfur combustion furnace, a layer of enclosure shell is additionally arranged outside a heat-preservation-free shell of the sulfur combustion furnace, an annular area between the enclosure shell and the heat-preservation-free shell serves as a heat exchange area, nitrogen or air serves as a heat exchange medium, dividing wall type heat exchange is carried out through the shell of the combustion furnace, the temperature of the nitrogen is increased, and the heat exchange efficiency is improved. The flue gas in the furnace is discharged after the temperature is gradually reduced; after being heated, the nitrogen is fed into the miniature high-temperature waste heat hot water boiler and exchanges heat with high-temperature waste heat water through the heat exchanger, and the cooled nitrogen is returned and circularly exchanges heat. The heated high-temperature waste heat supplied water is sent to downstream heat consumers and is continuously and circularly heated; the pressure of the flash steam is 0.1-0.6 MPa, and the flash steam is supplied as process steam, so that the flue gas waste heat can be greatly recovered when the normal operation of sulfur combustion is maintained.

Description

Technical Field

[0001] The utility model relates to a waste heat steam boiler based on the integration of a sulfur combustion furnace and nitrogen heat extraction, and belongs to the technical fields of salt chemical industry and waste heat recovery. Background Technique

[0002] Salt chemical plants based on seawater salt production can extract substances such as bromine and lithium from seawater or concentrated bitter brine after salt production. The basic principle of the commonly used "air blowing method for bromine production by chlorine oxidation" is as follows.

[0003] Under acidic conditions, using chlorine as an oxidant, bromide ions (Br-) are oxidized to bromine molecules (Br2), and the ionic reaction formula is as follows.

[0004] 2Br-+Cl2 = Br2+2Cl-.

[0005] The free bromine is blown out with air, so it is called the air blowing method.

[0006] Acidic bromine production uses sulfur dioxide as an absorbent, and fresh water spray is used to assist in absorbing the mixture of air and bromine. The absorbed liquid is called primary acid, and the chemical reaction formula is as follows.

[0007] Br2+SO2+2H2O = 2HBr+H2SO4.

[0008] The primary acid is introduced into chlorine for oxidation to re-free bromine and generate hydrochloric acid. The chemical reaction formula is as follows.

[0009] 2HBr+Cl2 = 2HCl+Br2.

[0010] Finally, bromine is distilled out with water vapor, and after condensation and separation, the finished bromine is obtained.

[0011] The process flow is described as follows.

[0012] Seawater (brine) is pumped to the blowing tower. Dilute acid and chlorine are added to the outlet pipeline of the pump. The mixed acidified and chlorinated brine sprays down from the upper part of the blowing tower. The blower blows air into the bottom of the tower. When the brine contacts the air, the free bromine in the brine is desorbed and blown out. The blown waste liquid is discharged from the bottom of the blowing tower and enters the salt field for salt drying. The mixed gas discharged from the top of the blowing tower is sent to the absorption tower and is mixed and absorbed by sulfur dioxide and water mist. The formed finished liquid is called primary acid, which is collected in the acid storage tank. The air purified by the foam catcher is agitated by the blower and enters the bottom of the blowing tower for recycling in the system. The primary acid is added from the top of the distillation tower, and water vapor and chlorine are introduced from the bottom. When the primary acid flows down along the packing from top to bottom, it contacts the chlorine and water vapor flowing from bottom to top, and is continuously oxidized and distilled. The mixture of bromine vapor and water vapor is discharged from the top of the tower, and after condensation and separation, liquid bromine is obtained, and the crude bromine water returns to the absorption tower for continuous circulation.

[0013] Among them, chlorine gas is usually produced by vaporizing liquid chlorine through a water bath tank. The process method is as follows: Feed the liquid chlorine into the water bath bottle, and connect its upper nozzle tightly with the chlorine gas clamp. Fill the chlorine gas water bath tank with water and use steam to heat the water in the tank. Control the temperature at 75°C - 83°C through a solenoid valve. This temperature range can achieve the vaporization of liquid chlorine and avoid the formation of nitrogen trichloride explosives. The vaporized chlorine gas is supplied out.

[0014] The preparation process of SO2 gas is as follows: Sulfur enters the sulfur combustion furnace through a distributor, burns with oxygen in the blown-in air at high temperature to generate sulfur dioxide gas. After air cooling and washing and cooling with circulating water, the temperature is controlled below 70°C, and then it enters the blow-suction tower for reduction absorption to produce the finished liquid for bromine production.

[0015] The bromine extraction and distillation process is as follows: The finished liquid is preheated by the recycled liquid, then enters the distillation tower and is oxidized by chlorine gas. At the same time, steam distillation is carried out, and bromine is distilled out. The temperature at the top of the tower is controlled at 80 - 90°C. After condensation, crude bromine is obtained. The bromine-distilled recycled liquid is cooled by heat exchange with brine and then enters the collection pool, and then is used for brine acidification.

[0016] There are obvious energy wastes in the above traditional seawater bromine extraction process. For example: The high-temperature flue gas (up to 600 - 700°C level) when preparing SO2 gas in the sulfur combustion furnace is not usually recovered because of its strong corrosiveness and small flue gas volume, but directly enters the water washing tower for spray cooling to 50 - 60°C level; The discharged waste sulfuric acid liquid (SH) is not usually recovered because of its extremely strong corrosiveness, small flow rate and low temperature grade, and finally is wasted in vain; Although the bromine-distilled recycled liquid discharged from the bromine extraction distillation tower is usually equipped with a special heat exchanger to recover part of the waste heat, due to the very poor heat transfer performance and high cost of the original special heat exchanger, the waste heat recovery amount is relatively small, so that the discharge temperature of the bromine-distilled recycled liquid is usually still as high as above 50 - 60°C, and the waste heat in its low-temperature section is still wasted in vain. At the same time, it leads to relatively more steam added, higher energy consumption and operation costs. In short, due to the strong corrosiveness and small flow rate of the relevant flue gas and the discharged process water, a large proportion of various waste heat resources are wasted in vain, and it is necessary to recover and utilize them to achieve energy conservation and consumption reduction. Utility Model Content

[0017] The purpose and task of the present utility model are, in view of the inherent technical limitations existing in the above seawater bromine extraction process, to adopt the method of setting a sleeve enclosure outside the sulfur combustion furnace, taking heat from the annular area by nitrogen or air, then heating high-temperature water, and generating steam through flash evaporation to recover the waste heat of the high-temperature flue gas, and using it for process production and heating domestic hot water.

[0018] The specific description of the present utility model is: A waste heat steam boiler based on the integration of a sulfur combustion furnace and nitrogen heat extraction, which is composed of an original combustion furnace and an SO2 flue gas water washing tower subsystem, a heat extraction from the combustion furnace body and a flash steam generating boiler subsystem, and their connecting pipelines and components. Among them, the original combustion furnace and the SO2 flue gas water washing tower subsystem include a sulfur combustion furnace 1, an ash sedimentation tank 2, a high-temperature SO2 flue 3, a water washing tower 4, a clean SO2 flue gas pipe 5, a Roots blower 6, a water washing pump 7, an absorption tower 9 and their connecting pipelines and components. The characteristic lies in that the heat extraction from the combustion furnace body and the flash steam generating boiler subsystem include a heat exchange sleeve 20, a micro high-temperature waste heat hot water boiler 10, a feed water pump 16, a flash tank 23, a forced draft fan 21, a compressed working medium gas storage tank 22, a mixing air damper 19 and their connecting pipelines and components. Among them, the heat exchange sleeve 20 is arranged on the outer side of the shell of the sulfur combustion furnace 1, and the closed annular space between the two is the area where the heat exchange working medium flows and exchanges heat. The air inlet of the heat exchange sleeve 20 is arranged at one end of the smoke outlet of the sulfur combustion furnace 1, and the air outlet of the heat exchange sleeve 20 is arranged at one end of the air inlet of the sulfur combustion furnace 1; the air outlet of the heat exchange sleeve 20 is connected to the high-pressure inlet of the mixing air damper 19 and the inlet of the inlet rectifying section 11 of the micro high-temperature waste heat hot water boiler 10. The micro high-temperature waste heat hot water boiler 10 also includes a shell 12, an ultra-large temperature difference heat exchanger 13 and an outlet converging section. The medium-temperature heat exchange working medium outlet of the outlet converging section is connected to the low-pressure outlet of the mixing air damper 19, the inlet of the forced draft fan 21 and the air outlet of the compressed working medium gas storage tank 22. The air outlet of the forced draft fan 21 is connected to the air inlet of the heat exchange sleeve 20; the water inlet of the ultra-large temperature difference heat exchanger 13 is connected to the outlet of the feed water pump 16, and the water outlet of the ultra-large temperature difference heat exchanger 13 is connected to the inlet of the water supply regulating valve 25 and the inlet of the bypass regulating valve 24. The outlet of the water supply regulating valve 25 is communicated with the water supply pipe of the high-temperature water supply G, and the outlet of the bypass regulating valve 24 is connected to the high-temperature water inlet of the flash tank 23. The steam outlet of the flash tank 23 is communicated with the steam supply pipe of the secondary steam Q, and the medium-temperature water outlet of the flash tank 23 is connected to the inlet of the feed water pump 16 and the water return pipe of the high-temperature return water H.

[0019] A safety valve group 14 and a water supply temperature sensor 15 are arranged on the water outlet pipe section of the ultra-large temperature difference heat exchanger 13. A medium-temperature mixed gas sensor 18 is arranged on the medium-temperature heat exchange working medium outlet pipe section of the micro high-temperature waste heat hot water boiler 10. A combustion furnace exhaust gas temperature sensor 17 is arranged on the high-temperature SO2 flue 3 at the flue gas outlet of the sulfur combustion furnace 1.

[0020] The operating temperature of the water supply temperature sensor 15 is controlled by the opening degree of the electric regulating valve at the outlet of the feed water pump 16; the low limit temperature of the medium-temperature mixed gas sensor 18 is controlled by the opening degree of the mixing air damper 19; the low limit temperature of the combustion furnace exhaust gas temperature sensor 17 is controlled by the flow rate adjusted by the forced draft fan 21 through a frequency converter or an air inlet guide vane.

[0021] The working medium in the compressed working medium gas storage tank 22 is high-pressure nitrogen or compressed air.

[0022] The heat exchange sleeve 20 is made of carbon steel or boiler steel, and a heat insulation layer is provided or not provided on the outside.

[0023] The ultra-large temperature difference heat exchanger 13 adopts a serpentine coil structure, a longitudinal tube bundle structure, a plate structure or a tube-and-plate structure.

[0024] The ultra-large temperature difference heat exchanger 13 adopts a smooth tube or finned tube structure.

[0025] The material of the ultra-large temperature difference heat exchanger 13 is carbon steel, ND steel, stainless steel 304 or stainless steel 316L.

[0026] The material of the feed water pump 16 is a high-temperature cast iron pump or a stainless steel water pump.

[0027] The beneficial effects of the present utility model are as follows.

[0028] (1) Aiming at the strong corrosiveness problem of high-temperature SO2 flue gas, based on the acid dew point control method, this patent ensures that the temperature of the inner wall of the sulfur combustion furnace shell and the boiler flue gas exhaust pipe in contact with the flue gas is always maintained above the acid dew point, so as to ensure that acid dew point corrosion will not occur and ensure that the original equipment system will not have corrosion problems during the waste heat recovery process.

[0029] (2) This patent adopts the method of setting a sleeve on the outer shell of the sulfur combustion furnace and exchanging heat through an annular area. The heat exchange medium is nitrogen or air, and there is no corrosion problem. Therefore, common carbon steels such as boiler steel, ND steel, stainless steel 304 or stainless steel 316L can be used as the heat exchange tube materials, thus greatly reducing the processing difficulty and cost of the heat exchanger and the entire waste heat boiler, and solving the problem of waste heat recovery from the sulfur combustion furnace flue gas.

[0030] (3) This waste heat boiler can produce high-parameter waste hot water, and can also produce saturated wet steam of 0.1 - 0.6 MPa grade through a flash tank, which is more convenient for reuse in process production.

[0031] (4) By accurately controlling the most critical boiler water supply temperature to meet the parameter requirements of the external heat source; controlling the sleeve inlet air temperature and the combustion furnace flue gas exhaust temperature to avoid serious corrosion problems, ensuring the safe, stable and reliable operation of the equipment, improving the service life, and significantly reducing the full-cycle operation cost. Brief Description of the Drawings

[0032] Figure 1 is a system schematic diagram of the conventional production process for preparing SO2 gas in seawater bromine extraction, Figure 2 is a system schematic diagram of the present utility model.

[0033] Figure 1 and2 The component numbers and names in it are as follows.

[0034] Sulphur burner 1, soot settling tank 2, high-temperature SO2 flue 3, water scrubber 4, clean SO2 gas pipe 5, Roots blower 6, water scrubbing pump 7, original heat exchanger 8, absorption tower 9, micro high-temperature waste heat hot water boiler 10, inlet rectifying section 11, outer shell 12, ultra-large temperature difference heat exchanger 13, safety valve group 14, water supply temperature sensor 15, feed water pump 16, combustion furnace exhaust gas temperature sensor 17, medium-temperature mixed gas sensor 18, mixing air damper 19, heat exchange sleeve 20, forced draft fan 21, compressed working medium gas storage tank 22, flash tank 23, bypass regulating valve 24, water supply regulating valve 25, ambient air A, make-up water B, bromine and air mixture BrA, finished liquid BrH, high-temperature water supply G, high-temperature return water H, secondary steam Q, spray water R, sulphur S, high-temperature SO2 flue gas S1, clean SO2 flue gas S2, spent sulphuric acid liquid SH. Specific embodiments

[0035] Figure 1 It is a system schematic diagram and an embodiment of the conventional production process for preparing SO2 gas in seawater bromine extraction. Figure 2 It is the system schematic diagram and an embodiment of the present invention.

[0036] The embodiments of the conventional production process for preparing SO2 gas in seawater bromine extraction are as follows. Refer to Figure 1 as shown. The conventional system consists of a sulphur burner 1, a soot settling tank 2, a high-temperature SO2 flue 3, a water scrubber 4, a clean SO2 gas pipe 5, a Roots blower 6, a water scrubbing pump 7, an original heat exchanger 8, an absorption tower 9 and their connecting pipelines and components. The air inlet of the sulphur burner 1 is connected to the air outlet of the Roots blower 6. The sulphur burner 1 is also provided with a feed inlet for sulphur S. The air inlet of the Roots blower 6 communicates with the ambient air A. The flue gas outlet of the sulphur burner 1 is connected to the inlet of the soot settling tank 2. The outlet of the soot settling tank 2 is connected to the flue gas inlet of the water scrubber 4 through the high-temperature flue 3 of the high-temperature SO2 flue gas S1. The flue gas outlet of the water scrubber 4 is the SO2 outlet pipe 5 of the clean SO2 flue gas S2, and its downstream is connected to the flue gas inlet of the absorption tower 9. The bottom acid liquid outlet of the water scrubber 4 is connected to the inlet of the water scrubbing pump 7. The outlet of the water scrubbing pump 7 is connected to the high-temperature side inlet of the original heat exchanger 8. The high-temperature side outlet of the original heat exchanger 8 is connected to the inlet of the spray device of the water scrubber 4 and communicates with the discharge pipe of the spent sulphuric acid liquid SH and the water supply pipe of the make-up water B. The low-temperature side inlet and outlet of the original heat exchanger 8 are respectively connected to the incoming water and the return water pipelines of the water to be heated. The absorption tower 9 is also provided with an inlet for spray water R, an inlet for the bromine and air mixture BrA and an outlet for the finished liquid BrH.

[0037] The specific embodiments of the present invention are as follows. Refer to Figure 2As shown in the figure. A waste heat steam boiler based on the integration of a sulfur combustion furnace and nitrogen heat extraction consists of an original combustion furnace and an SO2 flue gas water washing tower subsystem, a heat extraction from the combustion furnace body and a flash steam generation boiler subsystem, and their connecting pipelines and components. The original combustion furnace and SO2 flue gas water washing tower subsystem includes a sulfur combustion furnace 1, an ash sedimentation tank 2, a high-temperature SO2 flue 3, a water washing tower 4, a clean SO2 flue gas pipe 5, a Roots blower 6, a water washing pump 7, an absorption tower 9 and their connecting pipelines and components. It is characterized in that the heat extraction from the combustion furnace body and the flash steam generation boiler subsystem includes a heat exchange sleeve 20, a micro high-temperature waste heat hot water boiler 10, a feed water pump 16, a flash tank 23, a forced draft fan 21, a compressed working medium gas storage tank 22, a mixing air damper 19 and their connecting pipelines and components. The heat exchange sleeve 20 is arranged outside the shell of the sulfur combustion furnace 1, and the enclosed annular space between them is the area where the heat exchange working medium flows for heat exchange. The air inlet of the heat exchange sleeve 20 is arranged at one end of the smoke outlet of the sulfur combustion furnace 1, and the air outlet of the heat exchange sleeve 20 is arranged at one end of the air inlet of the sulfur combustion furnace 1; the air outlet of the heat exchange sleeve 20 is connected to the high-pressure inlet of the mixing air damper 19 and the inlet of the inlet rectifying section 11 of the micro high-temperature waste heat hot water boiler 10. The micro high-temperature waste heat hot water boiler 10 also includes a shell 12, an ultra-large temperature difference heat exchanger 13 and an outlet converging section. The medium-temperature heat exchange working medium outlet of the outlet converging section is connected to the low-pressure outlet of the mixing air damper 19, the inlet of the forced draft fan 21 and the air outlet of the compressed working medium gas storage tank 22. The air outlet of the forced draft fan 21 is connected to the air inlet of the heat exchange sleeve 20; the water inlet of the ultra-large temperature difference heat exchanger 13 is connected to the outlet of the feed water pump 16, and the water outlet of the ultra-large temperature difference heat exchanger 13 is connected to the inlet of the water supply regulating valve 25 and the inlet of the bypass regulating valve 24. The outlet of the water supply regulating valve 25 is communicated with the water supply pipe of the high-temperature water supply G, and the outlet of the bypass regulating valve 24 is connected to the high-temperature water inlet of the flash tank 23. The steam outlet of the flash tank 23 is communicated with the steam supply pipe of the secondary steam Q, and the medium-temperature water outlet of the flash tank 23 is connected to the inlet of the feed water pump 16 and the water return pipe of the high-temperature return water H.

[0038] A safety valve group 14 and a water supply temperature sensor 15 are arranged on the water outlet pipe section of the ultra-large temperature difference heat exchanger 13. A medium-temperature mixed gas sensor 18 is arranged on the medium-temperature heat exchange working medium outlet pipe section of the micro high-temperature waste heat hot water boiler 10. A combustion furnace exhaust gas temperature sensor 17 is arranged on the high-temperature SO2 flue 3 at the flue gas outlet of the sulfur combustion furnace 1.

[0039] The operating temperature of the water supply temperature sensor 15 is controlled by the opening of the electric regulating valve at the outlet of the feed water pump 16; the low limit temperature of the medium-temperature mixed gas sensor 18 is controlled by the opening of the mixing air damper 19; the low limit temperature of the combustion furnace exhaust gas temperature sensor 17 is controlled by the flow rate adjusted by the forced draft fan 21 through a frequency converter or an inlet air guide vane.

[0040] The working medium in the compressed working medium storage tank 22 is high-pressure nitrogen or compressed air.

[0041] The heat exchange sleeve 20 is made of carbon steel or boiler steel, and a heat insulation layer is provided or not provided on the outside.

[0042] The ultra-large temperature difference heat exchanger 13 adopts a serpentine coil structure, a longitudinal tube bundle structure, a plate structure or a tube-sheet structure.

[0043] The ultra-large temperature difference heat exchanger 13 adopts a smooth tube or finned tube structure.

[0044] The material of the ultra-large temperature difference heat exchanger 13 is made of carbon steel, ND steel, stainless steel 304 or stainless steel 316L.

[0045] The material of the feed water pump 16 is made of a high-temperature cast iron pump or stainless steel water.

[0046] It should be noted that the present utility model is based on key technologies such as recovering waste heat by setting a sleeve outside the combustion furnace shell to take heat and controlling the acid dew point to achieve high-temperature SO2 flue gas, high-temperature hot water flashing to produce steam, etc., and a complete set of new equipment and systems for high-temperature SO2 flue gas are proposed. According to this solution, there can be different specific implementation measures and specific implementation devices with different structures. The above specific implementation manners are only one of the implementation forms. Any other similar simple deformed implementation manners, such as simple increase or decrease, deformation, change of relative position of internal components and interfaces, simple combination and adjustment of external pipelines and components, etc., all fall within the protection scope of the present utility model.

Claims

1. A waste heat steam boiler based on the integration of a sulfur combustion furnace and nitrogen heat extraction, comprising an original combustion furnace and SO2 flue gas water washing tower subsystem and a combustion furnace body heat extraction and flash steam production boiler subsystem and its connecting pipelines and components, wherein the original combustion furnace and SO2 flue gas water washing tower subsystem comprises a sulfur combustion furnace (1), an ash settling tank (2), a high-temperature SO2 flue (3), a water washing tower (4), a clean SO2 flue gas pipe (5), a Roots blower (6), a water washing pump (7), an absorption tower (9) and its connecting pipelines and components, characterized in that: The combustion furnace body heat extraction and flash steam production boiler subsystem comprises a heat exchange sleeve (20), a micro high-temperature waste heat hot water boiler (10), a water supply pump (16), a flash tank (23), a blower (21), a compressed working medium gas storage tank (22), a mixing damper (19) and connecting pipes and components thereof, wherein the heat exchange sleeve (20) is arranged outside the shell of the sulfur combustion furnace (1), and the closed annular space between the two is a region where the heat exchange working medium flows and exchanges heat, wherein the air inlet of the heat exchange sleeve (20) is arranged at one end of the smoke outlet of the sulfur combustion furnace (1), and the air outlet of the heat exchange sleeve (20) is arranged at one end of the air inlet of the sulfur combustion furnace (1); the air outlet of the heat exchange sleeve (20) is connected to the high-pressure inlet of the mixing damper (19) and the inlet of the inlet rectifying section (11) of the micro high-temperature waste heat hot water boiler (10); the micro high-temperature waste heat hot water boiler (10) also comprises a shell (12), a super The large temperature difference heat exchanger (13) and the outlet tapered section, the medium temperature heat exchange medium outlet of the outlet tapered section is connected to the low pressure outlet of the mixing damper (19), the inlet of the blower (21) and the air outlet of the compressed medium gas storage tank (22), the air outlet of the blower (21) is connected to the air inlet of the heat exchange sleeve (20); wherein the water inlet of the large temperature difference heat exchanger (13) is connected to the outlet of the water feed pump (16), and the water outlet of the large temperature difference heat exchanger (13) is connected to the outlet of the water feed pump (16). The inlet of the water supply regulating valve (25) is connected to the inlet of the bypass regulating valve (24), the outlet of the water supply regulating valve (25) is connected to the water supply pipe of the high-temperature supply water (G), the outlet of the bypass regulating valve (24) is connected to the high-temperature water inlet of the flash tank (23), the steam outlet of the flash tank (23) is connected to the steam supply pipe of the secondary steam (Q), and the medium-temperature water outlet of the flash tank (23) is connected to the inlet of the feed water pump (16) and the water pipe of the high-temperature return water (H).

2. A waste heat steam boiler based on the integration of sulfur combustion furnace and nitrogen heat extraction as claimed in claim 1, characterized in that The water outlet pipe section of the ultra-large temperature difference heat exchanger (13) is provided with a safety valve group (14) and a water supply temperature sensor (15); the medium-temperature heat exchange medium outlet pipe section of the micro high-temperature waste heat hot water boiler (10) is provided with a medium-temperature mixed gas sensor (18); and the high-temperature SO2 flue (3) at the flue gas outlet of the sulfur combustion furnace (1) is provided with a combustion furnace exhaust temperature sensor (17).

3. A waste heat steam boiler based on the integration of sulfur combustion furnace and nitrogen heat extraction as claimed in claim 2, characterized in that The operating temperature of the water supply temperature sensor (15) is controlled by the opening of the electric regulating valve at the outlet of the water supply pump (16); the lower limit temperature of the medium temperature mixed gas sensor (18) is controlled by the opening of the mixing air door (19); and the lower limit temperature of the combustion furnace exhaust gas temperature sensor (17) is controlled by the flow rate adjusted by the blower (21) through the frequency converter or the air inlet guide vane.

4. A waste heat steam boiler based on the integration of sulfur combustion furnace and nitrogen heat extraction as claimed in claim 1, characterized in that The working fluid in the compressed working fluid gas storage tank (22) is high-pressure nitrogen or compressed air.

5. A waste heat steam boiler based on the integration of sulfur combustion furnace and nitrogen heat extraction as claimed in claim 1, characterized in that The heat exchange sleeve (20) is made of carbon steel or boiler steel, and may or may not have an insulation layer on the outside.

6. A waste heat steam boiler based on the integration of sulfur combustion furnace and nitrogen heat extraction as claimed in claim 1, characterized in that The ultra-large temperature difference heat exchanger (13) adopts a serpentine coil structure, a longitudinal tube bundle structure, a plate structure or a tube-sheet structure.

7. A waste heat steam boiler based on the integration of sulfur combustion furnace and nitrogen heat extraction as claimed in claim 1, characterized in that The ultra-large temperature difference heat exchanger (13) adopts a plain tube or fin tube structure.

8. A waste heat steam boiler based on the integration of sulfur combustion furnace and nitrogen heat extraction as claimed in claim 1, characterized in that The material of the ultra-large temperature difference heat exchanger (13) is carbon steel, ND steel, stainless steel 304 or stainless steel 316L.

9. A waste heat steam boiler based on the integration of sulfur combustion furnace and nitrogen heat extraction as claimed in claim 1, characterized in that The water supply pump (16) is made of a high-temperature cast iron pump or a stainless steel water pump.

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