High-pressure water pipe waste heat recovery system applied to sulfur acid making process

Abstract

The high-pressure water pipe waste heat recovery system comprises a low-temperature superheater, an economizer, a steam pocket and a flue, and a first evaporator, a high-temperature superheater, a second evaporator and a third evaporator are arranged in the flue; the economizer comprises a first economizer and a second economizer; a flue gas outlet of the sulfur burning furnace is communicated with a flue inlet, a flue outlet is communicated with a reaction gas inlet of the first-section converter, a reaction gas outlet of the first-section converter is communicated with a flue gas inlet of the low-temperature superheater, and a flue gas outlet of the low-temperature superheater is communicated with a reaction gas inlet of the second-section converter. A reaction gas outlet of the third-section converter is communicated with a flue gas inlet of the second economizer, and a reaction gas outlet of the fourth-section converter is communicated with a flue gas inlet of the first economizer. The invention has the advantages of simple structure and high efficiency. The device has the advantages that heat generated in the sulfur acid production process is fully utilized, and high-temperature superheated steam is output, so that the acid production cost is effectively saved.

Description

Technical Field

[0001] The invention relates to the technical field of sulfuric acid production equipment, and in particular to a waste heat recovery device in a sulfuric acid production process. Background Art

[0002] In recent years, due to the rapid development of the traditional fertilizer industry and the new energy battery industry, sulfuric acid, as one of the raw materials of these industries, its equipment has also become increasingly large-scale and high-parameterized along with the development of the industry and the demand for power generation.

[0003] The sulfuric acid production process includes sulfur incineration and conversion. Among them, sulfur incineration: sulfur vapor reacts with oxygen in the sulfur incinerator to generate sulfur dioxide, and a large amount of heat is released along with the reaction. Conversion: sulfur dioxide is converted into sulfur trioxide under the action of a catalyst in the converter. The converter includes several sections, usually four or five sections. Each section of the converter is equipped with a catalyst. The sulfur dioxide gas from the sulfur incinerator passes through each section of the converter in turn and is continuously converted into sulfur trioxide until it passes through the last section of the converter and the sulfur dioxide gas is completely converted into sulfur trioxide. The generated sulfur trioxide then enters the absorption tower to contact with concentrated sulfuric acid to generate sulfuric acid.

[0004] The above-mentioned process of converting sulfur dioxide into sulfur trioxide in each stage of the reformer is also an exothermic process. Each stage of the reformer is provided with a reaction gas inlet and a reaction gas outlet. The sulfur dioxide gas enters from the reaction gas inlet of a certain stage of the reformer, and then is discharged from the reaction gas outlet of the reformer, and then enters the next stage of the reformer after being cooled to the temperature required for the reaction of the next stage of the reformer.

[0005] How to maximize the utilization and recovery of flue gas waste heat in the sulfuric acid production process is a crucial technical issue for the entire sulfuric acid production process. It can not only achieve energy conservation and emission reduction, but also provide higher economic benefits for enterprises. Therefore, it is necessary to continuously study the waste heat recovery system for sulfuric acid production units to continuously improve the heat utilization efficiency. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, which can fully utilize the heat generated by the sulfuric acid production process.

[0007] In order to solve the above problems, the technical solution adopted by the present invention is: a high-pressure water pipe waste heat recovery system applied to sulfuric acid production process, including: a low-temperature superheater, an economizer, a steam drum, and a flue, wherein a flue inlet and a flue outlet are respectively arranged at both ends of the flue, and a first evaporator, a high-temperature superheater, a second evaporator and a third evaporator are arranged in sequence from the flue gas inlet to the flue gas outlet in the flue; the economizer includes a first economizer and a second economizer, and the first economizer, the second economizer and the low-temperature superheater all adopt a vertical box structure, and the first economizer low-temperature section and the first economizer high-temperature section are arranged in sequence from bottom to top in the box of the first economizer, and the first economizer box upper part is provided with a first economizer low-temperature section and a first economizer high-temperature section. A first economizer flue gas inlet and a first economizer flue gas outlet are provided, a second economizer flue gas inlet and a second economizer flue gas outlet are provided on the box body of the second economizer, and a low-temperature superheater flue gas inlet and a low-temperature superheater flue gas outlet are provided on the box body of the low-temperature superheater; the flue gas outlet of the sulfur incinerator is connected with the flue inlet, the flue outlet is connected with the reaction gas inlet of the first-stage reformer, the reaction gas outlet of the first-stage reformer is connected with the low-temperature superheater flue gas inlet, the low-temperature superheater flue gas outlet is connected with the reaction gas inlet of the second-stage reformer, the reaction gas outlet of the third-stage reformer is connected with the second economizer flue gas inlet, and the reaction gas outlet of the fourth-stage reformer is connected with the first economizer flue gas inlet.

[0008] Furthermore, in the aforementioned high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, the first economizer flue gas inlet and the first economizer flue gas outlet are respectively located at the upper and lower ends of the first economizer box; the second economizer flue gas inlet and the second economizer flue gas outlet are respectively located at the upper and lower ends of the second economizer box; the low-temperature superheater flue gas inlet is located on one side of the lower end of the low-temperature superheater box, and the low-temperature superheater flue gas outlet is located at the upper end of the low-temperature superheater box.

[0009] Furthermore, the aforementioned high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, wherein the water inlet of the low-temperature section of the first economizer is connected to the boiler feed water pipe, the water outlet of the low-temperature section of the first economizer is connected to the water inlet of the second economizer, the water outlet of the second economizer is connected to the water inlet of the high-temperature section of the first economizer, and the water outlet of the high-temperature section of the first economizer is connected to the steam drum; the saturated steam outlet on the steam drum is connected to the low-temperature superheater steam inlet, the low-temperature superheater steam outlet is connected to the high-temperature superheater steam inlet, and the high-temperature superheater steam outlet outputs superheated steam; each evaporator in the flue is provided with an evaporator inlet pipe and an evaporator outlet pipe, and the evaporator output pipe and evaporator inlet pipe of each evaporator are respectively connected to the steam drum.

[0010] Furthermore, in the aforementioned high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, the structure of each evaporator in the flue includes: an upright arranged evaporator heat exchange tube bundle, the upper end of the evaporator heat exchange tube bundle is connected to the evaporator upper header, the lower end of the evaporator heat exchange tube bundle is connected to the evaporator lower header, the evaporator upper header and the evaporator lower header are both located in the flue, one end of the evaporator input pipe is connected to the evaporator lower header, and one end of the evaporator output pipe is connected to the evaporator upper header.

[0011] Furthermore, in the aforementioned high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, the evaporator input pipe or the evaporator output pipe extends out of the flue through a connecting pipe assembly, and the structure of the connecting pipe assembly includes: a connecting pipe sealed and fixedly arranged on the flue, the inner end of the connecting pipe is located in the flue, and the outer end of the connecting pipe extends out of the flue, each evaporator input pipe and each evaporator output pipe are passed through a connecting pipe and extend out of the flue, and an expansion joint is arranged on the evaporator input pipe and the evaporator output pipe outside the flue, one end of the expansion joint is sealed and fixed to the evaporator input pipe or the evaporator output pipe, and the other end of the expansion joint is sealed and fixedly connected to the corresponding connecting pipe.

[0012] Furthermore, in the aforementioned high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, first evaporator side baffles are respectively provided on both sides of the evaporator heat exchange tube bundle of the first evaporator, and the upper and lower ends of the first evaporator side baffles on both sides of the first evaporator near one end of the flue gas inlet are respectively provided with a first evaporator top baffle and a first evaporator bottom baffle, the first evaporator top baffle is located below the evaporator upper header of the first evaporator and is fixedly arranged at the upper end of the evaporator heat exchange tube bundle of the first evaporator, the first evaporator bottom baffle is located above the evaporator lower header of the first evaporator and is fixedly arranged at the lower end of the evaporator heat exchange tube bundle of the first evaporator, the first evaporator side baffles on both sides and the first evaporator top baffle and the first evaporator bottom baffle form the first flue gas drainage port of the first evaporator; an inlet smoke chamber is provided at one end of the smoke inlet of the flue, the smoke inlet is located on one side of the inlet smoke chamber, and a cast filler baffle is provided at one end of the inlet smoke chamber near the first evaporator, and the cast filler baffle guides the high-temperature smoke into the first smoke drainage port.

[0013] Furthermore, in the aforementioned high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, second evaporator side baffles are respectively provided on both sides of the evaporator heat exchange tube bundle of the second evaporator, and the upper and lower ends of the second evaporator side baffles on both sides of the second evaporator near one end of the high-temperature superheater are respectively provided with a second evaporator top baffle and a second evaporator bottom baffle, the second evaporator top baffle is located below the evaporator upper header of the second evaporator and is fixedly arranged at the upper end of the evaporator heat exchange tube bundle of the second evaporator, the second evaporator bottom baffle is located above the evaporator lower header of the second evaporator and is fixedly arranged at the lower end of the evaporator heat exchange tube bundle of the second evaporator, the second evaporator side baffle, the second evaporator top baffle and the second evaporator bottom baffle form a second flue gas drainage port, and a flue baffle for guiding the high-temperature flue gas into the second flue gas drainage port is provided in the flue between the second evaporator and the superheater.

[0014] Furthermore, in the aforementioned high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, the first economizer box and the second economizer box are supported on the first economizer support and the second economizer support respectively.

[0015] Furthermore, in the aforementioned high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process, the flue is a horizontal cylindrical structure.

[0016] The advantages of the present invention are: 1. It can make full use of the heat generated in the sulfuric acid production process, output high-temperature superheated steam, and effectively save the cost of acid production. 2. The structure of the heat recovery system is simplified, and the evaporator adopts a water-tube heat exchange tube bundle. Compared with the shell and tube fire tube boiler, its safety is greatly improved and the amount of steel used is effectively reduced. 3. Arranging several evaporators and high-temperature superheaters in one flue can effectively reduce the overall footprint of the boiler. 4. Each evaporator in the flue adopts an upright heat exchange tube bundle, which greatly reduces the steam-water resistance, and can make the evaporator heated to produce a steam-water mixture that enters the steam drum through natural circulation, thereby reducing energy consumption from heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a high-pressure water pipe waste heat recovery system applied to a sulfuric acid production process according to the present invention.

[0018] Figure 2 It is a structural schematic diagram of the first evaporator.

[0019] Figure 3 yes Figure 1 A schematic diagram of the structure of the second evaporator shown in section BB.

[0020] Figure 4 yes Figure 1 Schematic diagram of the arrangement structure of the flue damper shown in the AA section. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0022] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, the high-pressure water pipe waste heat recovery system applied to the sulfuric acid production process includes: a low-temperature superheater 1, an economizer, a steam drum 2, and a flue 3, and the two ends of the flue 3 are respectively provided with a flue inlet 31 and a flue outlet 32. The first evaporator 4, the high-temperature superheater 5, the second evaporator 6 and the third evaporator 7 are sequentially arranged in the flue 3 from the flue gas inlet 31 to the flue gas outlet 32. In this embodiment, the flue 3 is a horizontal cylindrical structure. The horizontal cylindrical structure is not only convenient for the installation of the internal heat exchanger, but also has good pressure resistance and can effectively prevent leakage.

[0023] The economizer described in this embodiment includes a first economizer 8 and a second economizer 9. The first economizer 8, the second economizer 9, and the low-temperature superheater 1 all adopt a vertical box structure. In this embodiment, the box of the first economizer 8 and the box of the second economizer 9 are supported on the first economizer support 83 and the second economizer support 91 respectively.

[0024] The first economizer 8 has a first economizer low temperature section 81 and a first economizer high temperature section 82 arranged in order from bottom to top in the box body, and a first economizer flue gas inlet 801 and a first economizer flue gas outlet 802 arranged on the box body of the first economizer 8, and the first economizer flue gas inlet 801 and the first economizer flue gas outlet 802 are respectively located at the upper and lower ends of the box body of the first economizer 8. The second economizer 9 has a second economizer flue gas inlet 901 and a second economizer flue gas outlet 902 arranged on the box body, and the second economizer flue gas inlet 901 and the second economizer flue gas outlet 902 are respectively located at the upper and lower ends of the box body of the second economizer 9. A low-temperature superheater smoke inlet 101 and a low-temperature superheater smoke outlet 102 are provided on the box body of the low-temperature superheater 1. The low-temperature superheater smoke inlet 101 is located on one side of the lower end of the box body of the low-temperature superheater 1, and the low-temperature superheater smoke outlet 102 is located at the upper end of the box body of the low-temperature superheater 1.

[0025] The flue gas outlet of the sulfur incinerator is connected to the flue inlet 31, the flue outlet 32 ​​is connected to the reaction gas inlet of the first-stage reformer, the reaction gas outlet of the first-stage reformer is connected to the low-temperature superheater flue gas inlet 101, the low-temperature superheater flue gas outlet 102 is connected to the reaction gas inlet of the second-stage reformer, the reaction gas outlet of the third-stage reformer is connected to the second economizer flue gas inlet 901, the second economizer flue gas outlet 902 is connected to the reaction gas inlet of the fourth-stage reformer, and the reaction gas outlet of the fourth-stage reformer is connected to the first economizer flue gas inlet 801.

[0026] The first economizer low temperature section water inlet 811 of the first economizer low temperature section 81 is connected to the boiler feed water pipe 10, the first economizer low temperature section water outlet 812 of the first economizer low temperature section 81 is connected to the second economizer water inlet 91 of the second economizer 9, the second economizer water outlet 92 of the second economizer 9 is connected to the first economizer high temperature section water inlet 821 of the first economizer high temperature section 82, and the first economizer high temperature section water outlet 822 of the first economizer high temperature section 82 is connected to the drum 2. The saturated steam outlet on the drum 2 is connected to the low temperature superheater steam inlet 11, the low temperature superheater steam outlet 12 is connected to the high temperature superheater steam inlet 51, and the high temperature superheater steam outlet 52 outputs superheated steam.

[0027] Each evaporator in the flue 3 is provided with an evaporator input pipe and an evaporator output pipe, and the evaporator output pipe and the evaporator input pipe of each evaporator are respectively connected to the steam drum 2. Specifically, the first evaporator 4 is provided with a first evaporator output pipe 41 and a first evaporator input pipe 42; the second evaporator 6 is provided with a second evaporator output pipe 61 and a second evaporator input pipe 62; the third evaporator 7 is provided with a third evaporator output pipe 71 and a third evaporator input pipe 72. The first evaporator output pipe 41 and the first evaporator input pipe 42, the second evaporator output pipe 61 and the second evaporator input pipe 62, the third evaporator output pipe 71 and the third evaporator input pipe 72 are respectively connected to the steam drum 2.

[0028] The structure of each evaporator in the flue 3 includes: an evaporator heat exchange tube bundle arranged upright, the upper end of the evaporator heat exchange tube bundle is connected to the evaporator upper header, the lower end of the evaporator heat exchange tube bundle is connected to the evaporator lower header, the evaporator upper header and the evaporator lower header are both located in the flue, one end of the evaporator input pipe is connected to the evaporator upper header, and one end of the evaporator output pipe is connected to the evaporator lower header. Each evaporator in the flue 3 adopts an evaporator heat exchange tube bundle arranged upright, which can minimize the steam-water resistance and thus realize natural circulation. Specifically, the first evaporator 4 includes a first evaporator heat exchange tube bundle 43 arranged upright, the upper end of the first evaporator heat exchange tube bundle 43 is connected to the first evaporator upper header 44, and the lower end of the first evaporator heat exchange tube bundle 43 is connected to the first evaporator lower header 45. One end of the first evaporator input pipe 42 is connected to the first evaporator lower header 44, and one end of the first evaporator output pipe 41 is connected to the first evaporator upper header 44. The second evaporator 6 includes a second evaporator heat exchange tube bundle 63 arranged upright, the upper end of the second evaporator heat exchange tube bundle 63 is connected to the second evaporator upper header 64, and the lower end of the second evaporator heat exchange tube bundle 63 is connected to the second evaporator lower header 65. One end of the second evaporator input pipe 62 is connected to the second evaporator lower header 65, and one end of the second evaporator output pipe 61 is connected to the second evaporator upper header 64. The third evaporator 7 includes a third evaporator heat exchange tube bundle 73 arranged upright, the upper end of the third evaporator heat exchange tube bundle 73 is connected to the third evaporator upper header 74, and the lower end of the third evaporator heat exchange tube bundle 73 is connected to the third evaporator lower header 75. One end of the third evaporator input pipe 72 is connected to the third evaporator lower header 75, and one end of the third evaporator output pipe 71 is connected to the third evaporator upper header 74.

[0029] In this embodiment, each evaporator input pipe or evaporator output pipe extends out of the flue through the pipe assembly 30. Figure 2 As shown, the structure of the connecting pipe assembly 30 includes: a connecting pipe 301 sealed and fixedly arranged on the flue 3, the inner end of the connecting pipe 301 is located in the flue 3, the outer end of the connecting pipe 301 extends out of the flue 3, each evaporator input pipe and each evaporator output pipe are passed through a connecting pipe 301 and extend out of the flue 3, and an expansion joint 302 is arranged on the evaporator input pipe and the evaporator output pipe outside the flue 3, one end of the expansion joint 302 is sealed and fixed to the evaporator input pipe or the evaporator output pipe, and the other end of the expansion joint 302 is sealed and fixedly connected to the corresponding connecting pipe 301.

[0030] In this embodiment, first evaporator side baffles 46 are respectively provided on both sides of the first evaporator heat exchange tube bundle 43 of the first evaporator 4, and first evaporator top baffles 47 and first evaporator bottom baffles 48 are respectively provided on the upper and lower ends of the first evaporator side baffles 46 on both sides of the first evaporator heat exchange tube bundle 43 near one end of the flue gas inlet 31. The first evaporator top baffle 47 is located below the first evaporator upper header 44 of the first evaporator 4 and is fixedly arranged at the upper end position of the first evaporator heat exchange tube bundle 43 of the first evaporator 4. The bottom baffle plate 48 of the evaporator is located above the first evaporator lower header 45 of the first evaporator 4 and is fixedly arranged at the lower end position of the first evaporator heat exchange tube bundle 43 of the first evaporator 4. The first evaporator side baffle plates 46 on both sides, the first evaporator top baffle plate 47 and the first evaporator bottom baffle plate 48 form the first smoke inlet 49 of the first evaporator. At the same time, the first evaporator top baffle plate 47 and the first evaporator bottom baffle plate 48 play an effective role in binding and fixing the first evaporator side baffle plates 46 on both sides of the first evaporator heat exchange tube bundle 43. An inlet smoke chamber 311 is arranged at one end of the smoke inlet 31 of the flue 3. The smoke inlet 31 is located at one side of the inlet smoke chamber 311. A cast filler baffle plate 312 is arranged at one end of the inlet smoke chamber 311 close to the first evaporator 4. The cast filler baffle plate 312 guides the high-temperature smoke into the first smoke inlet 49. The inlet smoke chamber 311 plays a good buffering role. The setting of the cast filler baffle 312 and the setting of the first evaporator side baffle 46, the first evaporator top baffle 47 and the first evaporator bottom baffle 48 are all aimed at effectively guiding the high-temperature flue gas entering from the smoke inlet 31 to the inlet smoke chamber 311 to first exchange heat with the first evaporator heat exchange tube bundle 43, so as to avoid the high-temperature flue gas entering from the smoke inlet 31 to the inlet smoke chamber 311 directly flushing the first evaporator upper header 44 and the first evaporator lower header 45, thereby effectively avoiding the first evaporator upper header 44 and the first evaporator lower header 45 from being damaged due to excessive temperature.

[0031] Second evaporator side baffles 66 are respectively provided on both sides of the second evaporator heat exchange tube bundle 63 of the second evaporator 6, and second evaporator top baffles 67 and second evaporator bottom baffles 68 are respectively provided on the upper and lower ends of the second evaporator side baffles 65 on both sides of the second evaporator 6 near one end of the high-temperature superheater 5. The second evaporator top baffle 67 is located below the second evaporator upper header 64 of the second evaporator 6 and is fixed at the upper end position of the second evaporator heat exchange tube bundle 63 of the second evaporator 6. The second evaporator bottom baffle 68 is located above the second evaporator lower header 65 of the second evaporator 6 and is fixed at the lower end position of the second evaporator heat exchange tube bundle 63 of the second evaporator 6. The second evaporator side baffles 66, the second evaporator top baffle 67 and the second evaporator bottom baffle 68 form a second smoke drainage port 69. The second evaporator top baffle 67 and the second evaporator bottom baffle 68 play an effective role in pulling and fixing the second evaporator side baffles 66 on both sides of the second evaporator heat exchange tube bundle 63. A flue baffle 70 is provided on the inner wall of the flue 3 between the second evaporator 6 and the high-temperature superheater 5 to guide the high-temperature flue gas to the second flue gas inlet 69. Figure 4 As shown, in this embodiment, four flue baffles 70 are arranged around the inner wall of the flue 3, and the four flue baffles 70 guide the flue gas to the second flue gas outlet 69. The arrangement of the flue baffles 70 and the second flue gas outlet 69 guides the high-temperature flue gas to first exchange heat with the second evaporator heat exchange tube bundle 63, thereby preventing the high-temperature flue gas from being retained in the second evaporator upper header 64 and the second evaporator lower header 65, and preventing the second evaporator upper header 64 and the second evaporator lower header 65 from being damaged due to high temperature.

[0032] The flue gas flow is as follows: the high-temperature flue gas of about 985°C generated by the sulfur incinerator enters the inlet smoke chamber 311 from the flue gas outlet of the sulfur incinerator through the flue inlet 31 of the flue 3. The high-temperature flue gas in the inlet smoke chamber 311 sequentially exchanges heat with the first evaporator 4, the high-temperature superheater 5, the second evaporator 6 and the third evaporator 7 in the flue 3 to release heat, and the temperature is reduced to about 420°C. The high-temperature flue gas at the flue outlet 32 ​​enters the first-stage reformer through the reaction gas inlet of the first-stage reformer for reaction.

[0033] The high-temperature gas in the first-stage converter enters the low-temperature superheater 1 through the reaction gas outlet of the first-stage converter and the low-temperature superheater flue gas inlet 101. The low-temperature superheater 1 cools the high-temperature flue gas from about 609°C to 450°C, and then the high-temperature flue gas enters the second-stage converter through the low-temperature superheater flue gas outlet 102 for reaction. After the high-temperature flue gas reacts in the second-stage converter, it enters the third-stage converter for reaction. The high-temperature flue gas in the third-stage converter enters the second economizer 9 through the reaction gas outlet of the third-stage converter and the second economizer flue gas inlet 901 in turn, and the second economizer 9 reduces the flue gas temperature to 175°C. The high-temperature flue gas in the fourth-stage converter enters the first economizer 8 through the reaction gas outlet of the fourth-stage converter and the first economizer flue gas inlet 801. The high-temperature flue gas is cooled from 439°C to 165°C and then output from the first economizer flue gas outlet 802.

[0034] The water flow is as follows: the desalted water is deoxygenated and heated to 120°C by the deaerator, and then pressurized by the pump and enters the first economizer low temperature section 81, the second economizer 9, and the first economizer high temperature section 82 through the boiler feed water pipe 10, and is heated to about 291°C before entering the drum 2. The water in the drum 2 will enter each evaporator in the flue 3 through the first evaporator input pipe 42, the second evaporator input pipe 62, and the third evaporator input pipe 72, respectively. The steam-water mixture generated by the heat in the evaporator will then return to the drum 2 through the first evaporator output pipe 41, the second evaporator output pipe 61, and the third evaporator output pipe 71. The saturated steam of 314°C generated by the drum 2 enters the low temperature superheater 1 and the high temperature superheater 5 in turn, and the high temperature superheater steam outlet 52 outputs 9.8Mpa, 540°C high pressure superheated steam.

[0035] As can be seen from the above, the advantages of the present invention are: 1. It can make full use of the heat generated in the sulfuric acid production process, output high-temperature superheated steam, and effectively save the cost of acid production. 2. The structure of the heat recovery system is simplified, and the evaporator adopts a water-tube heat exchange tube bundle. Compared with the shell and tube fire tube boiler, its safety is greatly improved and the amount of steel used is effectively reduced. 3. Arranging several evaporators and high-temperature superheaters in a flue can effectively reduce the overall footprint of the boiler. 4. Each evaporator in the flue adopts an upright heat exchange tube bundle, which greatly reduces the steam-water resistance, and can make the evaporator heated to produce a steam-water mixture that enters the steam drum through natural circulation, thereby reducing energy consumption from heat.

Claims

1. High-pressure water pipe waste heat recovery system used in sulfuric acid production process, including: A low-temperature superheater, an economizer, and a steam drum, characterized in that: it also includes a flue, and a flue inlet and a flue outlet are respectively arranged at both ends of the flue, and a first evaporator, a high-temperature superheater, a second evaporator, and a third evaporator are arranged in sequence from the flue gas inlet to the flue gas outlet; the economizer includes a first economizer and a second economizer, and the first economizer, the second economizer, and the low-temperature superheater all adopt a vertical box structure, and the first economizer box body is sequentially arranged from bottom to top with a first economizer low-temperature section and a first economizer high-temperature section, and the first economizer box body is provided with a first economizer flue gas inlet and a first economizer flue gas inlet. The flue gas outlet of the sulfur incinerator is connected with the flue inlet, the flue outlet is connected with the reaction gas inlet of the first-stage reformer, the reaction gas outlet of the first-stage reformer is connected with the flue gas inlet of the low-temperature superheater, the flue gas outlet of the low-temperature superheater is connected with the reaction gas inlet of the second-stage reformer, the reaction gas outlet of the third-stage reformer is connected with the flue gas inlet of the second economizer, and the reaction gas outlet of the fourth-stage reformer is connected with the flue gas inlet of the first economizer.

2. The high-pressure water pipe waste heat recovery system for sulfuric acid production process according to claim 1 is characterized in that: The first economizer flue gas inlet and the first economizer flue gas outlet are respectively located at the upper and lower ends of the first economizer box; the second economizer flue gas inlet and the second economizer flue gas outlet are respectively located at the upper and lower ends of the second economizer box; the low-temperature superheater flue gas inlet is located on one side of the lower end of the low-temperature superheater box, and the low-temperature superheater flue gas outlet is located at the upper end of the low-temperature superheater box.

3. The high-pressure water pipe waste heat recovery system for sulfuric acid production process according to claim 1 is characterized in that: The water inlet of the low-temperature section of the first economizer is connected to the boiler feed water pipe, the water outlet of the low-temperature section of the first economizer is connected to the water inlet of the second economizer, the water outlet of the second economizer is connected to the water inlet of the high-temperature section of the first economizer, and the water outlet of the high-temperature section of the first economizer is connected to the steam drum; the saturated steam outlet on the steam drum is connected to the low-temperature superheater steam inlet, the low-temperature superheater steam outlet is connected to the high-temperature superheater steam inlet, and the high-temperature superheater steam outlet outputs superheated steam; each evaporator in the flue is provided with an evaporator inlet pipe and an evaporator outlet pipe, and the evaporator output pipe and evaporator inlet pipe of each evaporator are respectively connected to the steam drum.

4. The high-pressure water pipe waste heat recovery system for sulfuric acid production process according to claim 3 is characterized in that: The structure of each evaporator in the flue includes: an evaporator heat exchange tube bundle arranged upright, the upper end of the evaporator heat exchange tube bundle is connected to the evaporator upper header, the lower end of the evaporator heat exchange tube bundle is connected to the evaporator lower header, the evaporator upper header and the evaporator lower header are both located in the flue, one end of the evaporator input pipe is connected to the evaporator lower header, and one end of the evaporator output pipe is connected to the evaporator upper header.

5. The high-pressure water pipe waste heat recovery system applied to sulfuric acid production process according to claim 4 is characterized in that: The evaporator input pipe or the evaporator output pipe extends out of the flue through a pipe assembly. The structure of the pipe assembly includes: a pipe sealed and fixedly arranged on the flue, the inner end of the pipe is located in the flue, and the outer end of the pipe extends out of the flue. Each evaporator input pipe and each evaporator output pipe are inserted into a pipe and extend out of the flue. An expansion joint is arranged on the evaporator input pipe and the evaporator output pipe outside the flue, one end of the expansion joint is sealed and fixed to the evaporator input pipe or the evaporator output pipe, and the other end of the expansion joint is sealed and fixedly connected to the corresponding pipe.

6. The high-pressure water pipe waste heat recovery system for sulfuric acid production process according to claim 4 is characterized in that: First evaporator side baffles are respectively arranged on both sides of the evaporator heat exchange tube bundle of the first evaporator, and the upper and lower ends of the first evaporator side baffles on both sides of the first evaporator near one end of the flue gas inlet are respectively provided with a first evaporator top baffle and a first evaporator bottom baffle. The first evaporator top baffle is located below the evaporator upper header of the first evaporator and is fixedly arranged at the upper end of the evaporator heat exchange tube bundle of the first evaporator. The first evaporator bottom baffle is located above the evaporator lower header of the first evaporator and is fixedly arranged at the lower end of the evaporator heat exchange tube bundle of the first evaporator. The first evaporator side baffles on both sides and the first evaporator top baffle and the first evaporator bottom baffle form a first flue gas drainage port of the first evaporator; an inlet smoke chamber is arranged at one end of the smoke inlet of the flue, and the smoke inlet is located on one side of the inlet smoke chamber. A cast filler baffle is arranged at one end of the inlet smoke chamber near the first evaporator, and the cast filler baffle guides the high-temperature smoke into the first smoke drainage port.

7. The high-pressure water pipe waste heat recovery system for sulfuric acid production process according to claim 4 is characterized in that: Second evaporator side baffles are respectively arranged on both sides of the evaporator heat exchange tube bundle of the second evaporator, and second evaporator top baffles and second evaporator bottom baffles are respectively arranged on the upper and lower ends of the second evaporator side baffles on both sides of the second evaporator near one end of the high-temperature superheater. The second evaporator top baffle is located below the evaporator upper header of the second evaporator and is fixedly arranged on the upper end of the evaporator heat exchange tube bundle of the second evaporator. The second evaporator bottom baffle is located above the evaporator lower header of the second evaporator and is fixedly arranged on the lower end of the evaporator heat exchange tube bundle of the second evaporator. The second evaporator side baffles, the second evaporator top baffle and the second evaporator bottom baffle form a second flue gas drainage port, and a flue baffle for guiding the high-temperature flue gas into the second flue gas drainage port is arranged on the inner wall of the flue between the second evaporator and the superheater.

8. The high-pressure water pipe waste heat recovery system for sulfuric acid production process according to claim 1 is characterized in that: The first economizer box body and the second economizer box body are supported on the first economizer support and the second economizer support, respectively.

9. The high-pressure water pipe waste heat recovery system for sulfuric acid production process according to claim 1 is characterized in that: The flue is a horizontal cylindrical structure.

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