Device for improving high-pressure steam production rate of sulfuric acid device
By introducing components such as high-temperature absorption towers, flue gas heaters, and heat exchangers into the sulfuric acid plant, the flue gas is heated by high-temperature sulfuric acid, thereby increasing the flue gas temperature. This solves the problem of insufficient high-pressure steam production and achieves efficient thermal energy utilization and improved economic benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU SAIRUI TECH ENG CO LTD
- Filing Date
- 2025-05-23
- Publication Date
- 2026-05-05
AI Technical Summary
The existing sulfuric acid plant has insufficient high-pressure steam production, resulting in poor economic efficiency, and the thermal energy utilization in the low-temperature heat recovery system is inadequate.
Design an apparatus comprising a high-temperature absorption tower, a flue gas heater, a heat exchanger, an economizer, and a high-pressure waste heat boiler. The apparatus heats the flue gas with high-temperature sulfuric acid and increases the flue gas temperature using the heat exchanger, thereby increasing the production of high-pressure steam. Simultaneously, it utilizes the heat from the high-temperature sulfuric acid in the low-pressure steam system to produce low-pressure steam.
While ensuring the production of low-pressure steam, it increases the production rate of high-pressure steam, increases economic benefits, and makes full use of thermal energy, achieving efficient heat transfer and utilization.
Smart Images
Figure CN224194116U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of acid production heat energy recovery technology, specifically a device for improving the high-pressure steam production rate of sulfuric acid plants. Background Technology
[0002] Currently, the efficiency of the heat recovery system in the sulfuric acid industry is paramount to the profitability of the entire plant. The current steam production per ton of acid in sulfuric acid plants is: 1.25~1.32 t / t of acid from high-pressure steam (3.0~9.8 MPa, 450~540℃), and ~0.45 t / t of acid from low-pressure steam (0.6~1.0 MPa, saturated steam) from the low-temperature heat recovery system. There is a significant price difference between these two types of steam in the market; therefore, maximizing the production of high-pressure steam to generate greater economic benefits is an urgent pursuit for the sulfuric acid industry.
[0003] In sulfuric acid production, the process of absorbing SO3 from flue gas to produce sulfuric acid in the dry absorption section is also an exothermic reaction. To recover this heat of reaction, the primary conversion gas with a high SO3 concentration from the conversion section is sent to a high-temperature absorption tower in a low-temperature heat recovery system. High-temperature absorption is employed, first using primary sulfuric acid (99% concentration, approximately 200°C) to absorb the SO3, and then using a small amount of secondary sulfuric acid (98.5% concentration, approximately 60°C) to absorb the remaining SO3 in the process gas. The sulfuric acid from the two SO3 absorption processes is combined to generate high-temperature, high-concentration sulfuric acid at approximately 220°C. The high-temperature sulfuric acid can generate low-pressure saturated steam below 1.0 MPa. The flue gas exiting the high-temperature absorption tower, after being cooled by the secondary 98.5% concentration sulfuric acid at approximately 60°C, is only about 70°C. This portion of the flue gas needs to be heated to approximately 420°C before being sent to the converter for further catalytic conversion of SO2 into SO3 and absorption.
[0004] The high-temperature sulfuric acid at 220℃ and the flue gas at 70℃ have a sufficient temperature difference. Therefore, a device is designed to improve the high-pressure steam production rate of the sulfuric acid plant, utilizing the temperature gradient and heat of this high-temperature sulfuric acid to produce more high-pressure steam. Summary of the Invention
[0005] This invention aims to overcome the shortcomings of existing technologies by providing a device for improving the high-pressure steam production rate of sulfuric acid plants.
[0006] To achieve the above objectives, a device for improving the high-pressure steam production rate of a sulfuric acid plant is designed, comprising a high-temperature absorption tower, a flue gas heater, a heat exchanger, an economizer, and a converter. The flue gas outlet of the high-temperature absorption tower is connected to the flue gas inlet of the flue gas heater, the flue gas outlet of the flue gas heater is connected to the cold-side inlet of the heat exchanger, the hot-side flue gas outlet of the heat exchanger is connected to the flue gas inlet of the economizer, the flue gas outlet of the economizer is connected to the flue gas inlet of the high-temperature absorption tower, and the cold-side high-pressure feedwater outlet of the economizer is connected to a high-pressure waste heat boiler, which produces high-pressure steam. The acid-side inlet of the flue gas heater is connected to the acid-side outlet of the high-temperature absorption tower and / or the acid-side outlet of the low-pressure feedwater heater. The acid-side outlet of the flue gas heater is connected to the acid-side inlet of the low-pressure feedwater heater and / or other process equipment. The acid-side inlet of the high-temperature absorption tower is also connected to the acid-side inlet of the steam generator. The acid-side outlet of the steam generator is connected to the acid-side inlet of the low-pressure feedwater heater. The water-side inlet of the low-pressure feedwater heater is connected to the low-pressure feedwater. The water-side outlet of the low-pressure feedwater heater is connected to the water-side inlet of the steam generator. The steam generator produces low-pressure steam at its steam outlet.
[0007] The 220°C high-temperature sulfuric acid from the high-temperature absorption tower enters the acid-side inlet of the flue gas heater, heating the flue gas inside. The heated flue gas then enters the cold-side inlet of the heat exchanger from the flue gas outlet of the heat exchanger, raising the temperature of the flue gas entering the cold side of the heat exchanger from 70°C to 120°C~200°C. This portion of the flue gas heat is saved and transferred to the flue gas entering the economizer from the hot-side flue gas outlet of the heat exchanger, raising the temperature of the flue gas at the hot-side flue gas outlet of the heat exchanger to 300°C~390°C.
[0008] The acid-side outlet of the flue gas heater and the acid-side outlet of the steam generator are also connected to a diluent. The inlet of the diluent is connected to external sulfuric acid and dilution water. After being mixed in the diluent, the mixture is connected to the acid-side inlet of the high-temperature absorption tower.
[0009] The acid-side outlet of the high-temperature absorption tower is connected to the acid-side inlet of the flue gas heater and the acid-side inlet of the steam generator via a high-temperature acid circulation pump.
[0010] The acid side of the flue gas heater is provided with a high-temperature section and a low-temperature section. The acid side inlet of the high-temperature section is connected to the acid side outlet of the high-temperature absorption tower, the acid side outlet of the high-temperature section is connected to the acid side inlet of the low-pressure feedwater heater, the acid side inlet of the low-temperature section is connected to the acid side outlet of the low-pressure feedwater heater, and the acid side outlet of the low-temperature section is connected to other process equipment.
[0011] The high-temperature section acid-side outlet is also connected to the diluent inlet.
[0012] Compared with the prior art, this utility model improves the existing sulfuric acid plant by sending a portion of the high-temperature acid to the flue gas heater while ensuring the production of low-pressure steam, thereby transferring heat to the high-pressure steam system to increase the high-pressure steam yield and generate more economic benefits. Attached Figure Description
[0013] Figure 1 This is a structural schematic diagram of Embodiment 1 of the present utility model.
[0014] Figure 2 This is a structural schematic diagram of Embodiment 2 of the present invention.
[0015] Figure 3 This is a structural schematic diagram of Embodiment 3 of the present invention. Detailed Implementation
[0016] The present invention will be further described below with reference to the accompanying drawings. Example 1
[0017] like Figure 1 As shown, the flue gas outlet of the high-temperature absorption tower 1 is connected to the flue gas inlet of the flue gas heater 2. The flue gas outlet of the flue gas heater 2 is connected to the cold side inlet of the heat exchanger 3. The hot side flue gas outlet of the heat exchanger 3 is connected to the flue gas inlet of the economizer 4. The flue gas outlet of the economizer 4 is connected to the flue gas inlet of the high-temperature absorption tower 1. The cold side inlet of the economizer 4 is connected to high-pressure feedwater. The cold side high-pressure feedwater outlet of the economizer 4 is connected to the high-pressure waste heat boiler 5. The high-pressure waste heat boiler 5 produces high-pressure steam. The acid side inlet of the flue gas heater 2 is connected to the acid side outlet of the high-temperature absorption tower 1. The acid side outlet of the flue gas heater 2 is connected to the acid side inlet of the low-pressure feedwater heater 6. The acid side inlet of the high-temperature absorption tower 1 is also connected to the acid side inlet of the steam generator 7. The acid side outlet of the steam generator 7 is connected to the acid side inlet of the low-pressure feedwater heater 6. The water side inlet of the low-pressure feedwater heater 6 is connected to low-pressure feedwater. The water side outlet of the low-pressure feedwater heater 6 is connected to the water side inlet of the steam generator 7. The steam generator 7 produces low-pressure steam through its steam outlet.
[0018] The three outlets of converter 8 are connected to the hot side flue gas inlet of heat exchanger 3, the cold side outlet of heat exchanger 3 is connected to the inlet of heat exchanger 9, and the outlet of heat exchanger 9 is connected to the four inlet of converter 8.
[0019] The acid-side outlets of the flue gas heater 2 and the steam generator 7 are also connected to the diluent 10. The inlet of the diluent 10 is connected to external sulfuric acid and dilution water. After mixing in the diluent 10, the mixture is connected to the acid-side inlet of the high-temperature absorption tower 1. The added dilution water and acid are mixed in the diluent 10 and then enter the high-temperature absorption tower 1. The absorption of SO3 generates heat, which raises the temperature of the circulating acid.
[0020] The acid side outlet of the high-temperature absorption tower 1 is connected to the acid side inlet of the flue gas heater 2 and the acid side inlet of the steam generator 7 via the high-temperature acid circulation pump 11.
[0021] In this embodiment, the high-temperature sulfuric acid exiting the acid side of the high-temperature absorption tower 1 enters the flue gas heater 2 and the steam generator 7 to provide heat, heating the flue gas in the flue gas heater 2 and the water vapor in the steam generator 7. This increases the temperature of the cold-side flue gas entering the heat exchanger 3, reducing the amount of heat that needs to be transferred on the hot side of the heat exchanger 3. This also increases the temperature of the flue gas exiting the hot side of the heat exchanger 3, which is the temperature of the flue gas entering the economizer 4. The economizer 4 can then utilize more heat to heat the high-pressure feedwater entering the high-pressure waste heat boiler 5, achieving the goal of producing more high-pressure steam. The water vapor in the steam generator 7 is heated to produce low-pressure steam. A portion of the sulfuric acid flowing out from the acid side outlets of the flue gas heater 2 and the steam generator 7 then enters the low-pressure feedwater heater 6 to heat the low-pressure feedwater entering the low-pressure feedwater heater 6. The heated low-pressure feedwater then enters the steam generator 7 to produce low-pressure steam. The sulfuric acid exposed at the acid side outlet of the low-pressure feedwater heater 6 is then used in other equipment within the sulfuric acid plant.
[0022] The 220°C high-temperature sulfuric acid from the high-temperature absorption tower 1 enters the acid side inlet of the flue gas heater 2, heating the flue gas inside the heater 2. The heated flue gas then enters the cold side inlet of the heat exchanger 3 from the flue gas outlet of the heater 2, raising the temperature of the flue gas entering the cold side of the heat exchanger 3 from 70°C to 120°C~200°C. This portion of the flue gas heat is saved and used to raise the temperature of the flue gas entering the economizer 4 from the hot side outlet of the heat exchanger 3 from approximately 270°C to 300°C~390°C. Example 2
[0023] This embodiment only describes the differences from Embodiment 1; the similarities will not be repeated.
[0024] The difference between this embodiment and Embodiment 1 is that, Figure 2 As shown, in this embodiment, the acid-side inlet of the flue gas heater 2 is connected to the acid-side outlet of the low-pressure feedwater heater 6, and the acid-side outlet of the flue gas heater 2 is connected to external equipment.
[0025] In this embodiment, high-temperature sulfuric acid first flows through steam generator 7 and low-pressure feedwater heater 6, and then enters flue gas heater 2. Without affecting the low-pressure steam yield of the low-temperature heat recovery system, the heat of the sulfuric acid exiting the low-pressure feedwater heater is further utilized to produce high-pressure steam. Example 3
[0026] This embodiment only describes the differences from Embodiment 1; the similarities will not be repeated.
[0027] The difference between this embodiment and Embodiment 1 is that, Figure 3 As shown, in this embodiment, the acid side of the flue gas heater 2 is provided with a high-temperature section 2-1 and a low-temperature section 2-2. The acid side inlet of the high-temperature section 2-1 is connected to the acid side outlet of the high-temperature absorption tower 1, the acid side outlet of the high-temperature section 2-1 is connected to the acid side inlet of the low-pressure feedwater heater 6, the acid side inlet of the low-temperature section 2-2 is connected to the acid side outlet of the low-pressure feedwater heater 6, and the acid side outlet of the low-temperature section 2-2 is connected to external equipment.
[0028] The acid side outlet of the high-temperature section 2-1 is also connected to the inlet of diluent 10.
[0029] In this embodiment, high-temperature sulfuric acid first flows through the high-temperature section 2-1 of the steam generator 7 and flue gas heater 2 to ensure the production of high-pressure steam, and then enters the low-pressure feedwater heater 6 for the production of low-pressure steam. After entering the low-pressure feedwater heater 6, the sulfuric acid then enters the low-temperature section 2-2 of the flue gas heater 2 to provide heat. This approach increases the production of high-pressure steam while also considering the production of low-pressure steam, fully utilizing the heat from the sulfuric acid, improving thermal energy utilization, and achieving higher economic benefits.
[0030] In this invention, a low-pressure feedwater heater and a steam generator utilize the heat from high-temperature sulfuric acid to produce low-pressure steam of 0.6MPa to 1.0MPa. A flue gas heater, a heat exchanger, an economizer, and a high-pressure waste heat boiler work together to produce high-pressure steam of 3.0 to 9.8MPa using the heat from the high-temperature sulfuric acid. While ensuring the production of low-pressure steam, a portion of the high-temperature acid is sent to the flue gas heater, transferring heat to the high-pressure steam system to increase the high-pressure steam yield and generate greater economic benefits. Furthermore, the connecting pipes can be adjusted according to the required output of low-pressure and high-pressure steam to achieve the connection structures of Embodiments 1 to 3, simplifying operation and meeting actual on-site needs.
[0031] In practical use, the heat source for flue gas heater 2 can also be sulfuric acid at different temperature gradients in other locations within the low-temperature heat recovery system; other heat sources can also be selected, including but not limited to low-pressure steam and high-temperature hot water.
[0032] In practical applications, this invention can be used in other sulfuric acid production devices such as pyrite-based sulfuric acid production, copper smelting-based sulfuric acid production, and waste acid recovery.
Claims
1. An apparatus for improving the high-pressure steam production rate of a sulfuric acid plant, comprising a high-temperature absorption tower and a converter, characterized in that: The flue gas outlet of the high-temperature absorption tower (1) is connected to the flue gas inlet of the flue gas heater (2). The flue gas outlet of the flue gas heater (2) is connected to the cold-side inlet of the heat exchanger (3). The hot-side flue gas outlet of the heat exchanger (3) is connected to the flue gas inlet of the economizer (4). The flue gas outlet of the economizer (4) is connected to the flue gas inlet of the high-temperature absorption tower (1). The cold-side high-pressure feedwater outlet of the economizer (4) is connected to the high-pressure waste heat boiler (5). The high-pressure waste heat boiler (5) produces high-pressure steam. The acid-side inlet of the flue gas heater (2) is connected to the acid-side outlet of the high-temperature absorption tower (1) and... / or the acid side outlet of the low-pressure feedwater heater (6), the acid side outlet of the flue gas heater (2) is connected to the acid side inlet of the low-pressure feedwater heater (6) and / or external equipment, the acid side inlet of the high-temperature absorption tower (1) is also connected to the acid side inlet of the steam generator (7), the acid side outlet of the steam generator (7) is connected to the acid side inlet of the low-pressure feedwater heater (6), the water side inlet of the low-pressure feedwater heater (6) is connected to the low-pressure feedwater, the water side outlet of the low-pressure feedwater heater (6) is connected to the water side inlet of the steam generator (7), and the steam outlet of the steam generator (7) produces low-pressure steam.
2. The apparatus for improving the high-pressure steam production rate of a sulfuric acid plant according to claim 1, characterized in that: The 220°C high-temperature sulfuric acid from the high-temperature absorption tower (1) enters the acid side inlet of the flue gas heater (2) to heat the flue gas inside the flue gas heater (2). The heated flue gas enters the cold side inlet of the heat exchanger (3) from the flue gas outlet of the heat exchanger (2), raising the temperature of the flue gas entering the cold side of the heat exchanger (3) from 70°C to 120°C~200°C. This part of the flue gas heat is saved to the flue gas heat entering the economizer (4) from the hot side flue gas outlet of the heat exchanger (3), raising the flue gas temperature at the hot side flue gas outlet of the heat exchanger (3) to 300°C~390°C.
3. The apparatus for improving the high-pressure steam production rate of a sulfuric acid plant according to claim 1, characterized in that: The acid side outlet of the flue gas heater (2) and the acid side outlet of the steam generator (7) are also connected to the diluent (10). The inlet of the diluent (10) is connected to external sulfuric acid and dilution water. After being mixed in the diluent (10), the diluent is connected to the acid side inlet of the high temperature absorption tower (1).
4. The apparatus for improving the high-pressure steam production rate of a sulfuric acid plant according to claim 1, characterized in that: The acid side outlet of the high temperature absorption tower (1) is connected to the acid side inlet of the flue gas heater (2) and the acid side inlet of the steam generator (7) via a high temperature acid circulation pump (11).
5. The apparatus for improving the high-pressure steam production rate of a sulfuric acid plant according to claim 1, characterized in that: The flue gas heater (2) has a high-temperature section (2-1) and a low-temperature section (2-2) on the acid side. The acid side inlet of the high-temperature section (2-1) is connected to the acid side outlet of the high-temperature absorption tower (1). The acid side outlet of the high-temperature section (2-1) is connected to the acid side inlet of the low-pressure feed water heater (6). The acid side inlet of the low-temperature section (2-2) is connected to the acid side outlet of the low-pressure feed water heater (6). The acid side outlet of the low-temperature section (2-2) is connected to external equipment.
6. The apparatus for improving the high-pressure steam production rate of a sulfuric acid plant according to claim 5, characterized in that: The acid side outlet of the high-temperature section (2-1) is also connected to the inlet of the diluent (10).