Smelting acid-making flue gas conversion system

Abstract

The utility model discloses a smelting acid-making flue gas conversion system which comprises a flue gas blower, an air blower, a gas-gas heat exchanger A, a pre-reactor, a gas-liquid heat exchanger, a main reactor and an absorption tower, an inlet of the flue gas blower is respectively connected with a flue gas pipeline and a pure oxygen input pipeline; an outlet of the flue gas blower is respectively connected with a cold phase inlet of the gas-gas heat exchanger A and an inlet of the main reactor; an outlet of the air blower is connected with a cold phase inlet of the gas-gas heat exchanger A; a cold phase outlet of the gas-gas heat exchanger A is connected with an inlet of the pre-reactor; an outlet of the pre-reactor is connected with a hot phase inlet of the gas-liquid heat exchanger; a hot phase outlet of the gas-liquid heat exchanger is connected with an inlet of the main reactor; and the outlet of the main reactor is connected with the inlet of the absorption tower. According to the utility model, pure oxygen introduction and heat balance technologies are adopted, so that the conversion efficiency of sulfur dioxide flue gas is greatly improved, and the flue gas with high sulfur content can be effectively treated.

Description

Technical Field

[0001] The utility model relates to a smelting acid-making flue gas conversion system, belonging to the technical field of flue gas acid-making. Background Art

[0002] Sulfur-containing flue gas generated during smelting can be used to produce sulfuric acid. Common flue gas acidification systems include equipment such as fans, converters, absorption towers, and cooling towers. As production loads continue to increase, the sulfur content in chemical plant flue gas also continues to rise. This causes the original flue gas acidification system to operate at full load or overload for a long time, leading to a series of problems such as overheating of the contact coal inside the converter, excessive sulfur dioxide at the outlet of the absorption tower, and insufficient purification negative pressure. How to expand the capacity of the flue gas acidification system is one of the current research focuses. Common modification methods currently include increasing the capacity of the oxidation fan, adopting more efficient converters, and increasing the number or size of absorption towers. These can increase the system's processing capacity, improve the oxidation reaction efficiency and absorption efficiency, and thus increase sulfuric acid production. However, there are still problems such as high modification costs and increased energy consumption. Utility Model Content

[0003] The purpose of this utility model is to address the deficiencies in the existing technology and propose a smelting acid flue gas conversion system, which adopts pure oxygen introduction and heat balance technology to greatly improve the conversion efficiency of sulfur dioxide flue gas and can effectively treat flue gas with high sulfur content.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A smelting acid flue gas conversion system comprises a flue gas blower, an air blower, an air-to-air heat exchanger A, a pre-reactor, a gas-liquid heat exchanger, a main reactor, and an absorption tower; the inlet of the flue gas blower is respectively connected to a flue gas pipeline and a pure oxygen input pipeline; the outlet of the flue gas blower is respectively connected to the cold phase inlet of the air-to-air heat exchanger A and the inlet of the main reactor; the outlet of the air blower is connected to the cold phase inlet of the air-to-air heat exchanger A; the cold phase outlet of the air-to-air heat exchanger A is connected to the inlet of the pre-reactor; the outlet of the pre-reactor is connected to the hot phase inlet of the air-to-liquid heat exchanger; the hot phase outlet of the air-to-liquid heat exchanger is connected to the inlet of the main reactor; and the outlet of the main reactor is connected to the inlet of the absorption tower.

[0006] The working process of the smelting acid flue gas conversion system is as follows:

[0007] An oxygen mixture with a concentration of 99% is introduced into the flue gas containing high concentration of sulfur dioxide produced by smelting, and then sent to the smelting acid flue gas conversion system through a flue gas blower, and the flue gas is divided into two paths, one of which directly enters the main reactor, and the other flue gas is first mixed with the air delivered by the air blower, and then enters the gas-to-gas heat exchanger to be heated to the conversion reaction temperature, and then enters the pre-reactor for reaction. The reacted gas enters the gas-liquid heat exchanger. After heat exchange in the gas-liquid heat exchanger to adjust the temperature, the gas enters the main reactor together with another part of the flue gas for reaction, and the reacted gas is sent to the absorption tower for treatment to prepare sulfuric acid.

[0008] Furthermore, the smelting acid flue gas conversion system is further provided with an air-to-air heat exchanger B. The cold phase inlet of the air-to-air heat exchanger B is connected to the outlet of the flue gas blower and the outlet of the air blower, respectively, and the cold phase outlet of the air-to-air heat exchanger B is connected to the cold phase inlet of the air-to-air heat exchanger A. The hot phase inlet of the air-to-air heat exchanger B is connected to the outlet of the main reactor, and the hot phase outlet of the air-to-air heat exchanger B is connected to the absorption tower. The provision of the air-to-air heat exchanger B allows the high-temperature reaction gas after the reaction to be used to preheat the flue gas and air, facilitating the reaction of the flue gas in the pre-reactor. It also recovers the waste heat of the reaction gas, lowering the inlet temperature of the absorption tower and facilitating its operation.

[0009] Furthermore, the smelting acid flue gas conversion system is further provided with an air-to-air heat exchanger C, the cold phase inlet of the air-to-air heat exchanger C being connected to the outlet of the flue gas blower, the cold phase outlet of the air-to-air heat exchanger C being connected to the inlet of the main reactor, the hot phase inlet of the air-to-air heat exchanger C being connected to the outlet of the main reactor, and the hot phase outlet of the air-to-air heat exchanger C being connected to the hot phase inlet of the air-to-air heat exchanger B. Providing the air-to-air heat exchanger C to preheat the diverted flue gas reduces the temperature difference between the diverted flue gas and the reaction gas after passing through the pre-reactor, thereby facilitating control of the main reactor inlet temperature, thereby reducing reaction fluctuations in the main reactor and improving reaction stability and efficiency.

[0010] Furthermore, one or more economizers are connected in series between the main reactor and the absorption tower. By providing one or more economizers, waste heat of the reaction gas can be effectively recovered, the temperature of the gas entering the absorption tower can be regulated, and the working efficiency of the absorption tower can be improved.

[0011] Furthermore, the cold phase inlet of the gas-liquid heat exchanger is connected to the water supply pipe of the circulating water network, and the cold phase outlet of the gas-liquid heat exchanger is connected to the return pipe of the circulating water network. By introducing circulating water into the gas-liquid heat exchanger, the temperature of the gas after heat exchange can be timely and accurately regulated.

[0012] Furthermore, the hot phase inlet of the gas-to-gas heat exchanger A is connected to a steam network, and the hot phase outlet of the gas-to-gas heat exchanger A is connected to a waste heat recovery boiler. The waste heat recovery boiler can further recover waste heat and reduce energy loss.

[0013] Compared with the existing technology, this technical solution has the following beneficial effects:

[0014] 1. The utility model adopts a diversion technology to separate the sulfur dioxide drying flue gas from the flue gas fan into two paths and send them to the pre-reactor and the main reactor respectively. After the diversion, the excess reaction heat of the pre-reactor will be diverted to the first and second layers of the reaction bed, avoiding the catalyst heat resistance temperature of each layer exceeding 650°C in the pre-converter. At the same time, the introduction of pure oxygen improves the ability to treat high-concentration sulfur dioxide flue gas. Combined with the conversion diversion technology, it balances the material flow and reaction heat generated by the ultra-high-concentration sulfur dioxide flue gas, thereby promoting the smooth progress of the conversion reaction, improving the conversion reaction rate, and reducing the gas temperature after the conversion reaction. After the waste heat is recovered by the economizer, the flue gas temperature entering the absorption tower is lowered, the heat of the dry absorption process is reduced, and the operating pressure of the sulfuric acid cooler is reduced, effectively solving the problems of overheating of the flue gas entering the low-temperature absorption device and the final absorption, excessive acid mist, and shortened service life of the foam capture screen. At the same time, the effective recovery of waste heat also increases the medium-pressure and low-pressure steam production.

[0015] 2. The utility model has the technical characteristics of easy operation, reliable operation, wide adaptability to sulfur dioxide concentration, reduced vanadium catalyst usage, and lower fan energy consumption. It effectively solves the problems of overheating of the internal contact coal of the converter, excessive SO2 at the outlet of the absorption tower, and insufficient purification negative pressure caused by the sulfur content of the flue gas from the chemical plant far exceeding the design value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a connection diagram of the smelting acid flue gas conversion system described in Example 1.

[0017] Figure 2 This is a connection diagram of the smelting acid flue gas conversion system described in Example 2.

[0018] Figure numerals: 1-flue gas blower, 2-air blower, 3-gas-gas heat exchanger A, 4-pre-reactor, 5-gas-liquid heat exchanger, 6-main reactor, 7-absorption tower, 8-gas-gas heat exchanger B, 9-gas-gas heat exchanger C, 10-flue gas duct, 11-pure oxygen input duct, 12-economizer. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to the accompanying drawings and examples, but the present invention is not limited to the examples. Specific experimental conditions and methods not specified in the following examples are conventional methods commonly known to those skilled in the art.

[0020] Example 1: Figure 1 As shown, a smelting acid flue gas conversion system includes a flue gas blower 1, an air blower 2, an air-to-air heat exchanger A3, a pre-reactor 4, a gas-liquid heat exchanger 5, a main reactor 6, and an absorption tower 7; the inlet of the flue gas blower 1 is respectively connected to a flue gas pipeline 10 and a pure oxygen input pipeline 11; the outlet of the flue gas blower 1 is respectively connected to the cold phase inlet of the air-to-air heat exchanger A3 and the inlet of the main reactor 6; the outlet of the air blower 2 is connected to the cold phase inlet of the air-to-air heat exchanger A3; the cold phase outlet of the air-to-air heat exchanger A3 is connected to the inlet of the pre-reactor 4; the outlet of the pre-reactor 4 is connected to the hot phase inlet of the air-to-liquid heat exchanger 5; the hot phase outlet of the air-to-liquid heat exchanger 5 is connected to the inlet of the main reactor 6; the outlet of the main reactor 6 is connected to the inlet of the absorption tower 7; and two economizers 12 are connected in series between the main reactor 6 and the absorption tower 7.

[0021] The working process of the smelting acid flue gas conversion system is as follows:

[0022] An oxygen mixture with a concentration of 99% is introduced into the flue gas containing high concentration of sulfur dioxide produced by smelting, and then sent to the smelting acid flue gas conversion system through the flue gas blower 1, and the flue gas is divided into two paths, one of which directly enters the main reactor 6, and the other flue gas is first mixed with the air delivered by the air blower 2, and then enters the gas-to-gas heat exchanger to be heated to the conversion reaction temperature, and then enters the pre-reactor 4 for reaction. The reacted gas enters the gas-liquid heat exchanger 5. After heat exchange in the gas-liquid heat exchanger 5 to adjust the temperature, the gas enters the main reactor 6 together with the other part of the flue gas for reaction. The reacted gas passes through two economizers 12 and is sent to the absorption tower 7 for treatment to prepare sulfuric acid.

[0023] Example 2: Figure 2 As shown, the smelting acid-making flue gas conversion system described in this embodiment is different from the system described in Example 1 only in that the smelting acid-making flue gas conversion system is further provided with an air-to-air heat exchanger B8, the cold phase inlet of the air-to-air heat exchanger B8 is connected to the outlet of the flue gas blower 1 and the outlet of the air blower 2 respectively, and the cold phase outlet of the air-to-air heat exchanger B8 is connected to the cold phase inlet of the air-to-air heat exchanger A3; the hot phase inlet of the air-to-air heat exchanger B8 is connected to the outlet of the main reactor 6, and the hot phase outlet of the air-to-air heat exchanger B8 is connected to the absorption tower 7;

[0024] The smelting acid flue gas conversion system is also provided with an air-to-air heat exchanger C9, the cold phase inlet of the air-to-air heat exchanger C9 is connected to the outlet of the flue gas blower 1, the cold phase outlet of the air-to-air heat exchanger C9 is connected to the inlet of the main reactor 6, the hot phase inlet of the air-to-air heat exchanger C9 is connected to the outlet of the main reactor 6, and the hot phase outlet of the air-to-air heat exchanger C9 is connected to the hot phase inlet of the air-to-air heat exchanger B8.

[0025] Example 3: The only difference between the smelting acid flue gas conversion system described in this example and the system described in Example 1 is that the cold phase inlet of the gas-liquid heat exchanger 5 is connected to the water supply pipe of the circulating water network, and the cold phase outlet of the gas-liquid heat exchanger 5 is connected to the return pipe of the circulating water network; the hot phase inlet of the gas-to-gas heat exchanger A3 is connected to the steam network, and the hot phase outlet of the gas-to-gas heat exchanger A3 is connected to the waste heat recovery boiler.

[0026] The present invention is not limited to the above-mentioned embodiments. Those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A smelting acid flue gas conversion system, characterized by: The smelting acid flue gas conversion system comprises a flue gas blower (1), an air blower (2), an air-to-air heat exchanger A (3), a pre-reactor (4), a gas-liquid heat exchanger (5), a main reactor (6), and an absorption tower (7); the inlet of the flue gas blower (1) is respectively connected to a flue gas pipeline (10) and a pure oxygen input pipeline (11); the outlet of the flue gas blower (1) is respectively connected to the cold phase inlet of the air-to-air heat exchanger A (3) and the inlet of the main reactor (6); the outlet of the air blower (2) is connected to the cold phase inlet of the air-to-air heat exchanger A (3); the cold phase outlet of the air-to-air heat exchanger A (3) is connected to the inlet of the pre-reactor (4); the outlet of the pre-reactor (4) is connected to the hot phase inlet of the air-to-liquid heat exchanger (5); the hot phase outlet of the air-to-liquid heat exchanger (5) is connected to the inlet of the main reactor (6); and the outlet of the main reactor (6) is connected to the inlet of the absorption tower (7).

2. The smelting acid flue gas conversion system according to claim 1, characterized in that: The smelting acid flue gas conversion system is further provided with an air-to-air heat exchanger B (8), the cold phase inlet of the air-to-air heat exchanger B (8) is respectively connected to the outlet of the flue gas blower (1) and the outlet of the air blower (2), and the cold phase outlet of the air-to-air heat exchanger B (8) is connected to the cold phase inlet of the air-to-air heat exchanger A (3); the hot phase inlet of the air-to-air heat exchanger B (8) is connected to the outlet of the main reactor (6), and the hot phase outlet of the air-to-air heat exchanger B (8) is connected to the absorption tower (7).

3. The smelting acid flue gas conversion system according to claim 2, characterized in that: The smelting acid flue gas conversion system is also provided with an air-to-air heat exchanger C (9), the cold phase inlet of the air-to-air heat exchanger C (9) is connected to the outlet of the flue gas blower (1), the cold phase outlet of the air-to-air heat exchanger C (9) is connected to the inlet of the main reactor (6), the hot phase inlet of the air-to-air heat exchanger C (9) is connected to the outlet of the main reactor (6), and the hot phase outlet of the air-to-air heat exchanger C (9) is connected to the hot phase inlet of the air-to-air heat exchanger B (8).

4. The smelting acid flue gas conversion system according to claim 1, characterized in that: One or more economizers (12) are connected in series between the main reactor (6) and the absorption tower (7).

5. The smelting acid flue gas conversion system according to claim 1 is characterized in that: The cold phase inlet of the gas-liquid heat exchanger (5) is connected to the water supply pipe of the circulating water network, and the cold phase outlet of the gas-liquid heat exchanger (5) is connected to the return pipe of the circulating water network.

6. The smelting acid flue gas conversion system according to claim 1, characterized in that: The hot phase inlet of the gas-to-gas heat exchanger A (3) is connected to the steam network, and the hot phase outlet of the gas-to-gas heat exchanger A (3) is connected to the waste heat recovery boiler.

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