Process and device for utilizing heat energy in sulfuric acid production

Abstract

The present invention relates to the technical field of heat energy utilization, and in particular to a process and device for utilizing heat energy in sulfuric acid production. In the process for utilizing heat energy in sulfuric acid production, a first heat exchanger and / or a second heat exchanger and / or a third heat exchanger are additionally arranged in a sulfuric acid production process. The first heat exchanger heats air entering a sulfur incinerator, and high-temperature heat in flue gas is transferred into a steam system in a waste heat boiler to generate medium-pressure steam and high-pressure steam. The second heat exchanger heats flue gas from an HRS tower, and the heated flue gas enters a cold-hot heat exchanger for heat exchange with flue gas from an outlet of a third section of a converter to further increase the temperature, so as to meet process requirements. The third heat exchanger heats boiler feed water from a boiler feed water pump, the boiler feed water then enters an economizer 3A and / or an economizer 4B, and this portion of heat added by the boiler feed water is used for generating medium-pressure steam and high-pressure steam. Compared with the prior art, three heat exchangers are added, and are flexibly configured on the basis of different use scenarios and objects, significantly improving the yield of medium-pressure steam and high-pressure steam.

Description

Process and equipment for heat energy utilization in sulfuric acid production TECHNICAL FIELD

[0001] The present application relates to the technical field of heat energy utilization, in particular to a process and equipment for heat energy utilization in sulfuric acid production. BACKGROUND

[0002] At present, whether the heat energy recovery system of the sulfuric acid industry is efficient is the most important for the entire device. The ton acid steam production of the sulfur-burning sulfuric acid device is 1.25-1.32 t / t in the medium and high pressure steam of 3.0-9.8 MPa, 400-540 DEG C, the low temperature heat recovery system of the saturated steam of 0.6-1.0 MPa, which is called HRS (Heat Recovery Systems), produces 0.45 t / t of low pressure steam. The price difference of the two kinds of steam is large in the market. Therefore, it is urgent to improve the production of medium and high pressure steam as much as possible to produce more economic benefits for the sulfuric acid industry. SUMMARY

[0003] The present application provides a process and equipment for further utilization of heat energy in sulfuric acid production to transfer low temperature heat energy to high temperature heat energy and produce more medium and high pressure steam as much as possible to produce more economic benefits.

[0004] To achieve the above purpose, a process for heat energy utilization in sulfuric acid production is designed, and a first heat exchanger and / or a second heat exchanger and / or a third heat exchanger are added to the sulfuric acid production process,

[0005] The first heat exchanger 1-1 heats the air entering the sulfur incinerator. The heated air enters the sulfur incinerator. The flue gas after the combustion reaction enters the waste heat boiler. The high temperature heat in the flue gas is transferred to the steam system in the waste heat boiler to produce medium and high pressure steam.

[0006] The second heat exchanger 2-1 heats the flue gas from the HRS tower. The heated flue gas enters the cold and hot heat exchanger and exchanges heat with the flue gas from the outlet of the third section of the converter to further heat and meet the process requirements. The heat consumption of another flue gas from the cold and hot heat exchanger is reduced, and the high pressure hot water is heated by the economizer 3A to transfer the heat energy to the steam system for utilization.

[0007] The third heat exchanger 3-1 heats the boiler feed water from the boiler feed water pump and enters the economizer 3A and / or the economizer 4B, or enters the economizer 3A and / or the economizer 4B after being used as the heat source of the first heat exchanger 1-1 and the second heat exchanger 2-1. The increased heat of the boiler feed water is used to produce medium and high pressure steam.

[0008] Based on the above process of heat utilization in sulfuric acid production, the equipment includes a drying tower, a fan, a sulfur incinerator, a converter, an HRS tower, the drying tower inlet is connected with an air filter, the drying tower outlet is connected with one end of the main fan, the other end of the main fan is connected with the inlet of the sulfur incinerator, the outlet of the sulfur incinerator is connected with the inlet of the waste heat boiler, the outlet of the waste heat boiler is connected with the inlet of the first section of the converter, the outlet of the first section of the converter is connected with the inlet of the high-temperature superheater 1B, the outlet of the high-temperature superheater 1B is connected with the inlet of the second section of the converter, the outlet of the second section of the converter is connected with the first inlet of the hot heat exchanger, the first outlet of the hot heat exchanger is connected with the inlet of the third section of the converter, the outlet of the third section of the converter is connected with the first inlet of the cold heat exchanger, the first outlet of the cold heat exchanger is connected with the inlet of the economizer 3A, the outlet of the economizer 3A is connected with the flue gas inlet of the HRS absorption tower, the flue gas outlet of the HRS absorption tower is connected with the second inlet of the cold heat exchanger, the second outlet of the cold heat exchanger is connected with the second inlet of the hot heat exchanger, the second outlet of the hot heat exchanger is connected with the fourth inlet of the converter, the fourth outlet of the converter is connected with the flue gas inlets of the second absorption tower through the superheater 4A, the economizer 4B and the economizer 4A respectively, the flue gas outlet of the second absorption tower is connected with a tail suction device, the acid outlet of the second absorption tower is connected with a second absorption acid pump tank, the acid side outlet of the HRS absorption tower pump tank is connected with the inlet of the HRS boiler through an HRS acid circulating pump, the outlet of the HRS boiler is connected with the inlet of the HRS heater and the inlet of the HRS diluter respectively, the outlet of the HRS heater is connected with the acid side inlet of the HRS preheater, the acid outlet of the HRS preheater is connected with the second absorption acid pump tank, the acid outlet of the second absorption acid pump tank is connected with the inlet of the finished acid cooler, and the outlet of the finished acid cooler obtains finished acid.

[0009] The first heat exchanger is installed before the inlet of the sulfur incinerator, the second heat exchanger is installed between the HRS tower and the cold heat exchanger, and the third heat exchanger is installed between the boiler feed water pump and the economizer.

[0010] The first heat exchanger, the second heat exchanger and the third heat exchanger are all provided with temperature detection points and control valves, and the amount of material entering the heat exchanger is adjusted according to the set temperature parameter to control the temperature.

[0011] The heating medium in the first heat exchanger and the second heat exchanger is derived from one or more of high-temperature sulfuric acid, high-pressure hot water, high-pressure steam, low-pressure steam and external heat sources in the sulfuric acid production process.

[0012] The heat source of the third heat exchanger is derived from high-temperature sulfuric acid generated by the HRS tower, the high-temperature sulfuric acid enters the heat source medium inlet of the third heat exchanger to exchange heat with the boiler feed water, and then flows out from the heat source medium outlet of the third heat exchanger.

[0013] The first heat exchanger is selected as an air heater, the second heat exchanger is selected as a flue gas heater, and the third heat exchanger is selected as a high-pressure heater.

[0014] The first heat exchanger comprises a first heat source medium inlet, a first heat source medium outlet, a first heat exchange pipe, a first flue gas inlet, and a first flue gas outlet. The heat source enters from the first heat source medium inlet, enters the first heat source medium outlet after passing through the first heat exchange pipe, and the boiler feed water to be heated enters from the first flue gas inlet, absorbs the heat at the first heat exchange pipe, and then goes out from the first flue gas outlet. The second heat exchanger comprises a second heat source medium inlet, a second heat source medium outlet, a second heat exchange pipe, a second flue gas inlet, and a second flue gas outlet. The heat source enters from the second heat source medium inlet, enters the second heat source medium outlet after passing through the second heat exchange pipe, and the flue gas to be heated enters from the second flue gas inlet, absorbs the heat at the second heat exchange pipe, and then goes out from the second flue gas outlet. The third heat exchanger comprises a third heat source medium inlet, a third heat source medium outlet, a third heat exchange pipe, a boiler feed water inlet, and a boiler feed water outlet. The heat source enters from the third heat source medium inlet, enters the third heat source medium outlet after passing through the third heat exchange pipe, and the boiler feed water to be heated enters from the boiler feed water inlet, absorbs the heat at the third heat exchange pipe, and then goes out from the boiler feed water outlet.

[0015] The heat exchange pipes of the first heat exchanger and the second heat exchanger are finned tubes, the third heat exchanger is a shell-and-tube heat exchanger, and the materials in contact with high-temperature acid in the first heat exchanger, the second heat exchanger, and the third heat exchanger are acid-resistant stainless steel, and the materials in contact with hot water and steam are carbon steel.

[0016] The flue gas after being heated by the second heat exchanger goes out of the cold-hot heat exchanger, reduces the heat consumption of another flue gas going out of the cold-hot heat exchanger, and heats the high-pressure hot water through the coal economizer 3A to transfer the heat energy to the steam system for utilization.

[0017] In the sulfuric acid production process, air is filtered through an air filter, the filtered air is dried in a drying tower, and then the dried air is pressurized by a fan and enters a sulfur incinerator to burn and react with liquid sulfur to generate high-temperature SO2 flue gas. The flue gas enters a waste heat boiler to transfer the high-temperature heat in the flue gas to the steam system in the waste heat boiler to generate medium and high pressure steam. The flue gas after going out of the waste heat boiler enters a converter for catalytic oxidation. The flue gas after going out of the three-stage outlet of the converter is cooled by a cold-hot heat exchanger and a coal economizer 3A, and then enters an HRS tower for SO3 absorption. The flue gas at the outlet of the HRS tower is cooled by a cold-hot heat exchanger and a hot-hot heat exchanger, and then enters a four-stage converter for catalytic oxidation again. The flue gas at the outlet of the four-stage converter is cooled by a superheater 4A, a coal economizer 4B, and a coal economizer 4A, and then enters a secondary absorption tower for secondary SO3 absorption. The high-temperature sulfuric acid produced by the HRS tower is divided into two parts after passing through an HRS boiler. One part enters an HRS heater, enters a secondary absorption acid pump tank to react to generate sulfuric acid, and then passes through a finished acid cooler to obtain finished acid. The other part of the high-temperature sulfuric acid passes through an HRS diluter, is diluted by water and mixed with acid, and then returns to the HRS tower for repeated absorption.

[0018] The sulfuric acid production process includes, but is not limited to, sulfuric acid production, pyrite acid production, and smelting flue gas acid production.

[0019] Compared with the prior art, the present application increases three sets of heat exchangers, each of which can be used alone or in combination, and can be flexibly configured according to different use scenarios and objects, thereby significantly improving the yield of medium and high pressure steam. The high temperature sulfuric acid, hot water, steam, flue gas in the sulfuric acid production process or energy outside the sulfuric acid production process is used as a heat source as much as possible to improve the heat energy recycling rate. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is a process flow diagram of the flue gas and acid system in the sulfuric acid production process of the present application.

[0021] Fig. 2 is a process flow diagram of the water and steam in the sulfuric acid production process of the present application.

[0022] Fig. 3 is a structural schematic diagram of the first heat exchanger of the present application.

[0023] Fig. 4 is a side view of the first heat exchanger of the present application.

[0024] Fig. 5 is a structural schematic diagram of the second heat exchanger of the present application.

[0025] Fig. 6 is a side view of the second heat exchanger of the present application.

[0026] Fig. 7 is a structural schematic diagram of the third heat exchanger of the present application.

[0027] [Corr. according to Rule 91 07.08.2024] Referring to Figs. 1 to 7, wherein 1-1 is a first heat exchanger, 1-4 is a first heat source medium inlet, 1-5 is a first heat source medium outlet, 1-6 is a first heat exchange tube, 1-7 is a first flue gas inlet, 1-8 is a first flue gas outlet, 2-1 is a second heat exchanger, 2-4 is a second heat source medium inlet, 2-5 is a second heat source medium outlet, 2-6 is a second heat exchange tube, 2-7 is a second flue gas inlet, 2-8 is a second flue gas outlet, 3-1 is a third heat exchanger, 3-4 is a third heat source medium inlet, 3-5 is a third heat source medium outlet, 3-6 is a third heat exchange tube, 3-7 is a boiler feed water inlet, 3-8 is a boiler feed water outlet, 4-1 is liquid sulfur, 4-2 is air, 4-3 is an air filter, 4-4 is a drying tower, 4-5 is a main air blower, 4-6 is a sulfur burner, 4-7 is a waste heat boiler, 4-8 is a converter, 4-9 is a high-temperature superheater 1B, 4-10 is a hot heat exchanger, 4-11 is a cold heat exchanger, 4-12 is an economizer 3A, 4-13 is an ejector, 4-14 is low-pressure steam, 4-15 is an HRS tower, 4-16 is an HRS acid circulating pump, 4-17 is a superheater 4A, 4-18 is an economizer 4B, 4-19 is an economizer 4A, 4-20 is a secondary absorption tower, 4-21 is a tail absorption device, 4-22 is a secondary absorption acid pump tank, 4-23 is a secondary absorption acid cooler, 4-24 is a finished acid cooler, 4-25 is a finished acid, 4-26 is an HRS boiler, 4-27 is an HRS heater, 4-28 is an HRS diluter, 4-29 is another HRS heater, 4-30 is a dry acid pump tank, 4-31 is a dry acid cooler, 4-32 is a pump tank dilution water, 4-33 is HRS dilution water, 4-34 is desalinated water (0.4 Mpa), 4-35 is a deaerator, 4-36 is a boiler feed water pump, 4-37 is a boiler chemical feeding device, 4-38 is medium / high-pressure superheated steam, 4-39 is a continuous blowdown expander, 4-40 is a periodic blowdown expander, 4-41 is a vent port, 4-42 is a blowdown port, 4-43 is low-pressure saturated steam, 4-44 is low-pressure injection steam, 4-45 is an HRS blowdown tank, 4-46 is another vent port, 4-47 is another blowdown port, and 4-48 is low-pressure steam. DETAILED DESCRIPTION

[0028] The present application will be further described below with reference to the accompanying drawings.

[0029] As shown in Figs. 1 to 2, the present application is a process for utilizing heat energy in the production of sulfuric acid, specifically, a first heat exchanger 1-1 and / or a second heat exchanger 2-1 and / or a third heat exchanger 3-1 are added to the existing sulfuric acid production process,

[0030] The first heat exchanger 1-1 heats the air entering the sulfur incinerator from 60-130 DEG C to 180-280 DEG C, the heated air enters the sulfur incinerator, the flue gas after the combustion reaction enters the waste heat boiler, the high-temperature heat in the flue gas is transferred to the steam system in the waste heat boiler (i.e. the water vapor with serial number 118 in FIG. 2), and more medium and high pressure steam is generated.

[0031] The second heat exchanger 2-1 heats the flue gas (serial number 18) from the HRS tower from 70-90 DEG C to 100-190 DEG C, the heated flue gas (serial number 19) enters the cold and hot heat exchanger and exchanges heat with the flue gas (serial number 14) from the outlet of the third section of the converter to further heat to about 330 DEG C (serial number 20), reaching the process requirement; the temperature of the flue gas (serial number 14) from the outlet of the third section of the converter is 450-470 DEG C, the temperature of the flue gas (serial number 15) after heat exchange in the cold and hot heat exchanger is about 310-350 DEG C, and in the traditional process, the temperature at this point is usually about 250-280 DEG C, which is 60-100 DEG C higher, and the part of the heat that is higher in the improved process of the present application is the heat transferred and utilized from the low-temperature heat source, and this part of heat is absorbed and utilized by the coal economizer 3A to generate more medium and high pressure steam.

[0032] The third heat exchanger 3-1 heats the boiler feed water (serial number 110) from the boiler feed water pump from 104 DEG C-135 DEG C to 145 DEG C-150 DEG C, and then enters the coal economizer 3A and / or the coal economizer 4B, or enters the coal economizer 3A and / or the coal economizer 4B after being used as the heat source of the first heat exchanger 1-1 and the second heat exchanger 2-1. The temperature and heat of the boiler feed water to the coal economizer are improved, and finally the medium and high pressure steam production is improved.

[0033] Based on the above process of heat utilization in sulfuric acid production, the equipment includes drying tower, fan, sulfur incinerator, converter, HRS tower, the inlet of drying tower is connected with air filter, the outlet of drying tower is connected with one end of main fan, the other end of main fan is connected with the inlet of sulfur incinerator, the outlet of sulfur incinerator is connected with the inlet of waste heat boiler, the outlet of waste heat boiler is connected with the inlet of one section of converter, the outlet of one section of converter is connected with the inlet of high-temperature superheater 1B, the outlet of high-temperature superheater 1B is connected with the inlet of two sections of converter, the outlet of two sections of converter is connected with the first inlet of hot heat exchanger, the first outlet of hot heat exchanger is connected with the inlet of three sections of converter, the outlet of three sections of converter is connected with the first inlet of cold heat exchanger, the first outlet of cold heat exchanger is connected with the inlet of economizer 3A, the outlet of economizer 3A is connected with the flue gas inlet of HRS absorption tower, the flue gas outlet of HRS absorption tower is connected with the second inlet of cold heat exchanger, the second outlet of cold heat exchanger is connected with the second inlet of hot heat exchanger, the second outlet of hot heat exchanger is connected with the inlet of four sections of converter, the outlet of four sections of converter is connected with the inlet of double absorption tower through superheater 4A, economizer 4B and economizer 4A respectively, the flue gas outlet of double absorption tower is connected with tail suction device, the acid outlet of double absorption tower is connected with double absorption acid pump tank, the acid side outlet of HRS absorption tower pump tank is connected with the inlet of HRS boiler through HRS acid circulating pump, the outlet of HRS boiler is connected with the inlet of HRS heater and the inlet of HRS diluter respectively, the outlet of HRS heater is connected with the acid side inlet of HRS preheater, the acid outlet of HRS preheater is connected with double absorption acid pump tank, the acid outlet of double absorption acid pump tank is connected with the inlet of finished acid cooler, the outlet of finished acid cooler obtains finished acid.

[0034] The first heat exchanger 1-1 is installed before the inlet of sulfur incinerator, the second heat exchanger 2-1 is installed between HRS tower and cold heat exchanger, and the third heat exchanger 3-1 is installed between boiler feed water pump and economizer.

[0035] The first heat exchanger 1-1, the second heat exchanger 2-1 and the third heat exchanger 3-1 are provided with temperature detection points and control valves, and the amount of material entering the heat exchanger is adjusted according to the set temperature parameter to control the temperature.

[0036] The source of heating medium in the first heat exchanger 1-1 and the second heat exchanger 2-1 is one or more of high-temperature sulfuric acid, high-pressure hot water, high-pressure steam and low-pressure steam generated in the sulfuric acid production process. In specific use, heat sources outside the sulfuric acid production process can also be used. The source of high-temperature sulfuric acid includes one or more of flue gas 64, 66, 68, 72 and 73 in FIG. 1. The source of high-pressure hot water includes one or more of 111 and 113 in FIG. 2. The source of high-pressure steam includes one or more of 119 and 120 in FIG. 2. The source of high-pressure steam includes 125 in FIG. 2.

[0037] The heat source of the third heat exchanger 3-1 comes from the high-temperature sulfuric acid (No. 67) generated by the HRS tower, with a temperature of 200-230°C. The high-temperature sulfuric acid serves as the heat source medium of the third heat exchanger 3-1, exchanges heat with the high-pressure boiler feed water (No. 110), and then flows out from the heat source medium outlet 3-5 of the third heat exchanger 3-3.

[0038] The first heat exchanger 1-1 is an air heater, the second heat exchanger 2-1 is a flue gas heater, and the third heat exchanger 3-1 is an HRS high-pressure heater.

[0039] As shown in FIGS. 3-4, the first heat exchanger 1-1 includes a first heat source medium inlet 1-4, a first heat source medium outlet 1-5, a first heat exchange tube 1-6, a first flue gas inlet 1-7, and a first flue gas outlet 1-8. Inside the first heat exchanger shell 1-2, the heat source enters from the first heat source medium inlet 1-4, passes through the first heat exchange tube 1-6, and then enters the first heat source medium outlet 1-5. The boiler feed water to be heated enters from the first flue gas inlet 1-7, absorbs the heat at the first heat exchange tube 1-6, and then exits from the first flue gas outlet 1-8.

[0040] As shown in FIGS. 5-6, the second heat exchanger 2-1 includes a second heat source medium inlet 2-4, a second heat source medium outlet 2-5, a second heat exchange tube 2-6, a second flue gas inlet 2-7, and a second flue gas outlet 2-8. Inside the second heat exchanger shell 2-2, the heat source enters from the second heat source medium inlet 2-4, passes through the second heat exchange tube 2-6, and then enters the second heat source medium outlet 2-5. The flue gas to be heated enters from the second flue gas inlet 2-7, absorbs the heat at the second heat exchange tube 2-6, and then exits from the second flue gas outlet 2-8.

[0041] As shown in FIG. 7, the third heat exchanger 3-1 includes a third heat source medium inlet 3-4, a third heat source medium outlet 3-5, a third heat exchange tube 3-6, a boiler feed water inlet 3-7, and a boiler feed water outlet 3-8. Inside the third heat exchanger shell 3-3, the heat source enters from the third heat source medium inlet 3-4, passes through the third heat exchange tube 3-6, and then enters the third heat source medium outlet 3-5. The boiler feed water to be heated enters from the boiler feed water inlet 3-7, absorbs the heat at the third heat exchange tube 3-6, and then exits from the boiler feed water outlet 3-8.

[0042] The heat exchange tubes of the first heat exchanger 1-1 and the second heat exchanger 2-1 are finned tubes to enhance the heat exchange effect. The third heat exchanger 3-1 is a shell-and-tube heat exchanger. The materials in contact with high-temperature acid in the first heat exchanger 1-1, the second heat exchanger 2-1, and the third heat exchanger 3-1 are acid-resistant stainless steel, and the materials in contact with hot water and steam are carbon steel.

[0043] In this embodiment, the flue gas (No. 15) after being heated by the second heat exchanger 2-1 is discharged from the cold-heat heat exchanger, reduces the heat consumed by another flue gas discharged from the cold-heat heat exchanger, and heats the high-pressure hot water (No. 112) through the coal economizer 3A, so as to transfer the heat energy to the steam system for utilization.

[0044] In the sulfuric acid production process, air is filtered through an air filter, the filtered air is dried in a drying tower, and then the dried air is pressurized by a fan and enters a sulfur incinerator to burn and react with liquid sulfur to generate high-temperature SO2 flue gas. The flue gas enters a waste heat boiler to transfer the high-temperature heat in the flue gas to the steam system in the waste heat boiler to generate medium and high pressure steam. After being discharged from the waste heat boiler, the flue gas enters a converter for catalytic oxidation. After being discharged from the third stage outlet of the converter, the flue gas is cooled by a cold-heat heat exchanger, a coal economizer 3A, and then enters an HRS tower for SO3 absorption. The flue gas at the outlet of the HRS tower is cooled by a cold-heat heat exchanger, a hot-heat heat exchanger, and then enters a fourth stage of the converter for catalytic oxidation again. The flue gas at the outlet of the fourth stage of the converter is cooled by a superheater 4A, a coal economizer 4B, and a coal economizer 4A, and then enters a secondary absorption tower for secondary absorption of SO3. The high-temperature sulfuric acid produced by the HRS tower is combined after passing through an HRS boiler and a third heat exchanger, and then divided into two parts. One part enters an HRS heater and then enters a secondary absorption acid pump tank to react to generate sulfuric acid, and then passes through a finished acid cooler to obtain finished acid. The other part of the high-temperature sulfuric acid passes through an HRS diluter, is diluted with water and mixed with acid, and then returns to the HRS tower for repeated absorption process.

[0045] The sulfuric acid production process includes but is not limited to sulfur-burning acid production, pyrite-burning acid production, and smelter flue gas-burning acid production. Embodiment

[0046] In this embodiment, a first heat exchanger 1-1 is added to the existing sulfuric acid production process. The high-temperature sulfuric acid obtained by the HRS tower is used to heat the air entering the sulfur incinerator, so as to transfer the low-temperature heat energy to the medium and high pressure steam system.

[0047] In another embodiment of the present embodiment, the residual heat (No. 111) in the third heat exchanger 3-1 in the system is used to heat the air entering the sulfur incinerator, so as to transfer the low-temperature heat energy to the subsequent medium and high pressure steam system.

[0048] In another embodiment of the present embodiment, an external heat source generated by an external device is used to heat the air entering the sulfur incinerator, so as to transfer the low-temperature heat energy to the subsequent medium and high pressure steam system. Embodiment

[0049] In this embodiment, a second heat exchanger 2-1 is added to the existing sulfuric acid production process. The high-temperature sulfuric acid obtained by the HRS tower is used to heat the flue gas at the outlet of the HRS tower, so as to transfer the low-temperature heat energy to the medium and high pressure steam system.

[0050] In another embodiment of the present embodiment, the low-temperature heat energy is transferred to the medium and high pressure steam system by using the flue gas at the outlet of the HRS tower as heat source to heat the flue gas at the outlet of the HRS tower.

[0051] In another embodiment of the present embodiment, the low-temperature heat energy is transferred to the medium and high pressure steam system by using the heat source generated by an external device to heat the flue gas at the outlet of the HRS tower. Embodiment

[0052] In the present embodiment, a third heat exchanger 3-1 is added to the existing sulfuric acid production process. The high-temperature sulfuric acid obtained by the HRS tower is used to heat the medium and high pressure boiler feed water, so as to transfer the low-temperature heat energy to the subsequent medium and high pressure steam system. Embodiment

[0053] In the present embodiment, a first heat exchanger 1-1 and a second heat exchanger 2-1 are added to the existing sulfuric acid production process. The high-temperature sulfuric acid obtained by the HRS tower is used to heat the air entering the sulfuric acid furnace and / or the flue gas at the outlet of the HRS tower, so as to transfer the low-temperature heat energy to the medium and high pressure steam system.

[0054] In another embodiment of the present embodiment, the low-temperature heat energy is transferred to the medium and high pressure steam system by using the high-temperature sulfuric acid obtained by the HRS tower to generate low-pressure steam, and then using the low-pressure steam to heat the air entering the sulfuric acid furnace and / or the flue gas at the outlet of the HRS tower. Embodiment

[0055] In the present embodiment, only the differences from Embodiment 1 are described, and the same parts are not described again.

[0056] The difference between the present embodiment and Embodiment 1 is that a third heat exchanger is added to the sulfuric acid production process in the present embodiment. The high-temperature sulfuric acid obtained by the HRS tower is used to heat the medium and high pressure boiler feed water, so as to transfer the low-temperature heat energy to the subsequent medium and high pressure steam system. Embodiment

[0057] In the present embodiment, only the differences from Embodiment 2 are described, and the same parts are not described again.

[0058] The difference between the present embodiment and Embodiment 2 is that a third heat exchanger is added to the sulfuric acid production process in the present embodiment. The high-temperature sulfuric acid obtained by the HRS tower is used to heat the medium and high pressure boiler feed water, so as to transfer the low-temperature heat energy to the subsequent medium and high pressure steam system. Embodiment

[0059] In the present embodiment, only the differences from Embodiment 4 are described, and the same parts are not described again.

[0060] The embodiment is different from the embodiment four in that a third heat exchanger is additionally arranged in the sulfuric acid production process.

[0061] The application increases three sets of heat exchangers, each of which can be used alone or in combination, and is flexibly configured according to different use scenarios and objects, thereby significantly improving the yield of medium and high pressure steam. The high temperature sulfuric acid, hot water, steam and flue gas in the sulfuric acid production process are used as heat sources as much as possible to improve the heat energy recycling rate. Through the heat exchange system, the low temperature heat energy is transferred to the high temperature heat energy system, the medium and high pressure steam 1.41-1.55 t / t acid can be realized, and the low pressure steam 0.31-0.26 t / t acid can be realized, thereby maximizing the economic benefit.

Claims

1. A process for the utilization of thermal energy in sulfuric acid production, characterized by: The sulfuric acid production process is additionally provided with a first heat exchanger (1-1) and / or a second heat exchanger (2-1) and / or a third heat exchanger (3-1), The first heat exchanger (1-1) heats the air entering the sulfur incinerator, the heated air enters the sulfur incinerator, the flue gas after the combustion reaction enters the waste heat boiler, the high-temperature heat in the flue gas is transferred to the steam system in the waste heat boiler to generate medium and high-pressure steam; The second heat exchanger (2-1) heats the flue gas from the HRS tower, the heated flue gas enters the cold and hot heat exchanger and exchanges heat with the flue gas from the third outlet of the converter to further heat up to meet the process requirements, reduce the heat consumption of another flue gas from the cold and hot heat exchanger, and heat the high-pressure hot water through the economizer 3A to transfer the heat energy to the steam system for utilization; The third heat exchanger (3-1) heats the boiler feed water from the boiler feed water pump and enters the economizer 3A and / or the economizer 4B, or enters the economizer 3A and / or the economizer 4B after being used as the heat source of the first heat exchanger 1-1 and the second heat exchanger 2-1, and the increased heat of the part of the boiler feed water is used to generate medium and high-pressure steam. Based on the above-mentioned process for utilizing heat energy in sulfuric acid production, the equipment includes a drying tower, a fan, a sulfur incinerator, a converter, an HRS tower, the inlet of the drying tower is connected with an air filter, one end of the outlet of the drying tower is connected with a main fan, the other end of the main fan is connected with the inlet of the sulfur incinerator, the outlet of the sulfur incinerator is connected with the inlet of a waste heat boiler, the outlet of the waste heat boiler is connected with the inlet of a first stage of the converter, the outlet of the first stage of the converter is connected with the inlet of a high-temperature superheater 1B, the outlet of the high-temperature superheater 1B is connected with the inlet of a second stage of the converter, the outlet of the second stage of the converter is connected with the first inlet of a hot heat exchanger, the first outlet of the hot heat exchanger is connected with the inlet of a third stage of the converter, the outlet of the third stage of the converter is connected with the first inlet of a cold and hot heat exchanger, the first outlet of the cold and hot heat exchanger is connected with the inlet of the economizer 3A, the outlet of the economizer 3A is connected with the flue gas inlet of an HRS absorption tower, the flue gas outlet of the HRS absorption tower is connected with the second inlet of the cold and hot heat exchanger, the second outlet of the cold and hot heat exchanger is connected with the second inlet of the hot heat exchanger, the second outlet of the hot heat exchanger is connected with the fourth inlet of the converter, the fourth outlet of the converter is connected with the flue gas inlet of a second absorption tower through a superheater 4A, an economizer 4B and an economizer 4A, respectively, the flue gas outlet of the second absorption tower is connected with a tail suction device, the acid outlet of the second absorption tower is connected with a second absorption acid pump tank, the acid side outlet of the HRS absorption tower pump tank is connected with the inlet of an HRS boiler, the outlet of the HRS boiler is connected with the inlet of an HRS heater and the inlet of an HRS diluter, respectively, the outlet of the HRS heater is connected with the acid side inlet of an HRS preheater, the acid outlet of the HRS preheater is connected with the second absorption acid pump tank, the acid outlet of the second absorption acid pump tank is connected with the inlet of a finished acid cooler, and the outlet of the finished acid cooler obtains finished acid. The first heat exchanger (1-1) is installed before the inlet of the sulfur incinerator, the second heat exchanger (2-1) is installed between the HRS tower and the cold and hot heat exchanger, and the third heat exchanger (3-1) is installed between the boiler feed water pump and the economizer.

2. A process and apparatus for utilization of heat energy in sulfuric acid production according to claim 1, characterized in that: The first heat exchanger (1-1), the second heat exchanger (2-1) and the third heat exchanger (3-1) are provided with temperature detection points and control valves, and the amount of material entering the heat exchanger is adjusted according to the set temperature parameter to control the temperature.

3. A process and apparatus for heat energy utilization in sulfuric acid production according to claim 1, characterized in that: The heating medium in the first heat exchanger (1-1) and the second heat exchanger (2-1) is derived from one or more of high-temperature sulfuric acid, high-pressure hot water, high-pressure steam, low-pressure steam and external heat source in the sulfuric acid production process.

4. A process and apparatus for heat energy utilization in sulfuric acid production according to claim 1, characterized in that: The heat source of the third heat exchanger (13-1) is high-temperature sulfuric acid generated by the HRS tower, which enters the heat source medium inlet (3-4) of the third heat exchanger (3-1) to exchange heat with the boiler feed water, and then flows out from the heat source medium outlet (3-5) of the third heat exchanger (3-1).

5. A process and apparatus for heat energy utilization in sulfuric acid production according to claim 1, characterized in that: The first heat exchanger (1-1) is an air heater, the second heat exchanger (2-1) is a flue gas heater, and the third heat exchanger (3-1) is a high-pressure heater.

6. A process and apparatus for heat energy utilization in sulfuric acid production according to claim 5, characterized in that: The first heat exchanger (1-1) comprises a first heat source medium inlet (1-4), a first heat source medium outlet (1-5), a first heat exchange pipe (1-6), a first flue gas inlet (1-7) and a first flue gas outlet (1-8). The heat source enters from the first heat source medium inlet (1-4), enters the first heat source medium outlet (1-5) after passing through the first heat exchange pipe (1-6), and the boiler feed water to be heated enters from the first flue gas inlet (1-7), absorbs the heat of the first heat exchange pipe (1-6), and then goes out from the first flue gas outlet (1-8). The second heat exchanger (2-1) comprises a second heat source medium inlet (2-4), a second heat source medium outlet (2-5), a second heat exchange pipe (2-6), a second flue gas inlet (2-7) and a second flue gas outlet (2-8). The heat source enters from the second heat source medium inlet (2-4), enters the second heat source medium outlet (2-5) after passing through the second heat exchange pipe (2-6), and the flue gas to be heated enters from the second flue gas inlet (2-7), absorbs the heat of the second heat exchange pipe (2-6), and then goes out from the second flue gas outlet (2-8). The third heat exchanger (3-1) comprises a third heat source medium inlet (3-4), a third heat source medium outlet (3-5), a third heat exchange pipe (3-6), a boiler feed water inlet (3-7) and a boiler feed water outlet (3-8). The heat source enters from the third heat source medium inlet (3-4), enters the third heat source medium outlet (3-5) after passing through the third heat exchange pipe (3-6), and the boiler feed water to be heated enters from the boiler feed water inlet (3-7), absorbs the heat of the third heat exchange pipe (3-6), and then goes out from the boiler feed water outlet (3-8).

7. A process and apparatus for heat energy utilization in sulfuric acid production according to claim 1 or 6, characterized in that: The heat exchange pipes of the first heat exchanger (1-1) and the second heat exchanger (2-1) are finned tubes, the third heat exchanger (3-1) is a shell-and-tube heat exchanger, and the materials in contact with high-temperature acid in the first heat exchanger (1-1), the second heat exchanger (2-1) and the third heat exchanger (3-1) are acid-resistant stainless steel, and the materials in contact with hot water and steam are carbon steel.

8. A process and apparatus for heat energy utilization in sulfuric acid production according to claim 1, characterized by the fact that: The second heat exchanger (2-1) is used to heat the flue gas, and the flue gas from the cold-heat exchanger reduces the heat consumption of another flue gas from the cold-heat exchanger, and the high-pressure hot water is heated through the coal economizer 3A to transfer the heat energy to the steam system for utilization.

9. A process and apparatus for heat energy utilization in sulfuric acid production according to claim 1, characterized by the fact that: In the sulfuric acid production process, air is filtered through an air filter, the filtered air is dried in a drying tower, then the dried air is pressurized by a fan and enters a sulfur incinerator to burn and react with liquid sulfur to generate high-temperature SO2 flue gas, the flue gas enters a waste heat boiler to transfer the high-temperature heat in the flue gas to the steam system in the waste heat boiler to generate medium and high pressure steam, the flue gas from the waste heat boiler enters a converter for catalytic oxidation, the flue gas from the three-stage outlet of the converter is cooled by a cold-heat exchanger, a coal economizer 3A and then enters an HRS tower for SO3 absorption, the flue gas from the outlet of the HRS tower is cooled by a cold-heat exchanger and a hot-heat exchanger and then enters a four-stage converter for catalytic oxidation again, the flue gas from the outlet of the four-stage converter is cooled by a superheater 4A, a coal economizer 4B and a coal economizer 4A and then enters a secondary absorption tower for secondary SO3 absorption, high-temperature sulfuric acid generated by the HRS tower is divided into two parts after passing through an HRS boiler, one part enters an HRS heater and then enters a secondary absorption acid pump tank to react to generate sulfuric acid, and then passes through a finished acid cooler to obtain finished acid, and the other part of the high-temperature sulfuric acid passes through an HRS diluter, is diluted by water and mixed with serial acid and then returns to the HRS tower for repeated absorption process.

10. A process and apparatus for heat energy utilization in sulfuric acid production according to claim 1, characterized in that: The sulfuric acid production process includes but is not limited to sulfuric acid production from sulfur, pyrite and smelting flue gas.

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