A device for replacing a high-temperature sulfuric acid pump without stopping

Abstract

The utility model discloses a device of high temperature sulfuric acid pump is changed without stopping, including high temperature circulating pump tank, air extraction device and gas phase balance pipe control valve, high temperature circulating pump tank top is equipped with gas phase balance pipe interface, and two high temperature sulfuric acid pumps are arranged in parallel on high temperature circulating pump tank, wherein at least one is the standby pump, air extraction device includes the air draught fan and air draught pipe of flange connection in high temperature circulating pump tank top to the first valve and the second valve of setting in the import end of air draught pipe and export end, the export end of air draught pipe is connected to the connecting pipe section between two suction tower export and tail suction pipeline, and gas phase balance pipe control valve sets up on gas phase balance pipe, is used for blocking the gas communication between high temperature absorption tower and high temperature circulating pump tank. Can change without stopping, greatly reduces the maintenance workload, shortens the operation time, reduces the operation risk, and guarantees the safety production.

Description

Technical Field

[0001] This utility model relates to the technical field of low-temperature heat recovery devices in sulfuric acid production, and in particular to a device for replacing high-temperature sulfuric acid pumps without stopping the machine. Background Technology

[0002] In chemical production processes such as sulfuric acid production from sulfur or smelting, a low-temperature heat recovery unit (HRS) is typically added to recover heat from flue gas and absorb heat. This involves the primary conversion gas from the conversion section entering the bottom of a high-temperature absorption tower, passing through two layers of packing material, and then countercurrently contacting high- and low-temperature concentration sulfuric acid. Mass and heat transfer occur, and most of the SO3 in the flue gas is absorbed. The absorption tail gas is then returned to the conversion system after the acid mist is removed by a demister at the top of the tower.

[0003] The high-temperature absorption tower adopts a two-stage absorption. The first stage uses high-temperature 99% sulfuric acid for absorption, and the second stage uses 98.5% low-temperature sulfuric acid for absorption. After absorption by the two layers of packing, the concentration and temperature of sulfuric acid both increase to generate high-temperature concentrated sulfuric acid. The high-temperature concentrated sulfuric acid merges at the bottom of the tower and enters the high-temperature circulation tank. After being pressurized by the high-temperature circulation pump, it is sent to the evaporator. In the evaporator, the high-temperature concentrated sulfuric acid exchanges heat with the evaporator feed water to generate low-pressure steam of 0.6 MPg.

[0004] Currently, sulfuric acid plants are developing towards large-scale operations, with the highest domestic capacity reaching 1.2 million tons per year, and some overseas plants even operating at 1.7 million tons per year. However, due to the high flow rate of high-temperature sulfuric acid pumps, the procurement cost is high, and considering the stress on the pump tank and the inconvenience of pump replacement, single-pump operation is generally adopted. Some units, with pump flow rates exceeding 2400 cubic meters per hour, use two small-flow pumps operating simultaneously. Due to material corrosion and wear of the submersible pump bearing bushings, replacement is required every 1-2 years. Since the temperature inside the pump tank is generally around 160 degrees Celsius, with a residual pressure of 10 kPa, a large amount of SO3 gas volatilizes, posing a significant health hazard, necessitating shutdown for pump replacement. During shutdowns, the main blower, sulfur incinerator, boiler, and other thermal equipment, converters, and dry suction units all need to be shut down for cooling, requiring at least two days for maintenance and restart, resulting in significant production losses. Therefore, designing a non-stop high-temperature sulfuric acid pump replacement system is essential to reduce production losses and minimize manpower and safety risks. Thus, a non-stop high-temperature sulfuric acid pump replacement system needs to be designed to solve the aforementioned technical problems. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a device for replacing high-temperature sulfuric acid pumps without stopping the machine. This device can replace the pumps without stopping the machine, greatly reducing maintenance workload, shortening operation time, reducing operational risks, and ensuring safe production.

[0006] To achieve the above-mentioned technical effects, the technical solution adopted by this utility model is as follows:

[0007] A device for non-stop replacement of high-temperature sulfuric acid pumps includes a high-temperature circulating pump tank, an extraction device, and a gas phase balance pipe control valve. The high-temperature circulating pump tank has a gas phase balance pipe interface at its top, and two high-temperature sulfuric acid pumps are arranged side-by-side on the tank, with at least one being a standby pump. The extraction device includes an induced draft fan and an induced draft pipe connected to the top of the high-temperature circulating pump tank via a flange, as well as a first valve at the inlet end and a second valve at the outlet end of the induced draft pipe. The outlet end of the induced draft pipe is connected to a connecting pipe section between the outlet of the secondary absorption tower and the tail suction pipe. The gas phase balance pipe control valve is located on the gas phase balance pipe and is used to block the gas communication between the high-temperature absorption tower and the high-temperature circulating pump tank.

[0008] Preferably, the inlet end of the induced draft fan is connected to the opening at the top of the high-temperature circulating pump tank through the first valve, the outlet end is connected to the induced draft pipe through the second valve, and the end of the induced draft pipe is connected to the negative pressure section from the outlet of the second suction tower to the tail suction pipe.

[0009] Preferably, a detachable blind plate is provided between the first valve and the second valve to isolate the connection between the induced draft fan and the high-temperature circulating pump tank.

[0010] Preferably, the two high-temperature sulfuric acid pumps are configured as follows: one pump operates at %-% of the design maximum flow rate, and the other pump serves as a backup; or both pumps operate simultaneously, with the total flow rate matching the design flow rate of a single pump.

[0011] Preferably, the induced draft fan is a variable frequency centrifugal induced draft fan, whose motor frequency is adjustable to maintain the negative pressure state in the high-temperature circulating pump tank.

[0012] Preferably, the gas phase balance pipe control valve is a manual valve or an automatic control valve. When closed, it blocks the flue gas from the high-temperature absorption tower from entering the high-temperature circulating pump tank, while allowing external air to be supplied to the pump tank through the air extraction device.

[0013] Preferably, the connection point between the exhaust pipe and the outlet of the second suction tower to the tail suction pipe is located before the inlet of the tail suction tower, and the connection point is arranged at an angle downward to prevent liquid backflow.

[0014] Furthermore, based on the existing high-temperature absorption tower, high-temperature circulating pump tank, and one circulating pump, a new negative energizer and negative evacuation device are added, and a manual valve or control valve is added to the gas phase balance pipe. Additionally, a high-temperature sulfuric acid pump of the same specifications is added to the circulating pump tank.

[0015] Furthermore, the valves before and after the vacuum pump are normally closed. To prevent internal leakage of the valves, a figure-eight blind flange can be added before the valve. Before maintenance, remove the blind flange, open the valve, start the induced draft fan, and after normal operation, disassemble the faulty pump, check the pump tank pressure and remote transmission pressure, and adjust the frequency converter of the induced draft fan motor to maintain the negative pressure state. When opening the valves before and after the vacuum pump, close the valve on the gas phase balance pipe at the same time to ensure that it is closed.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] This device reduces costs, with the total investment in the added induced draft fan, valves, and corresponding pipelines not exceeding 100,000 yuan; it reduces maintenance workload, shortens operation time to less than 2 hours, and reduces operational risks by eliminating the emission of high-temperature toxic gases, thus ensuring safe production. It completely eliminates production losses caused by shutdowns. Based on an annual production of 1.2 million tons of sulfuric acid (60-110% load), the corresponding increase in sulfuric acid production is 4,800-8,000 tons, with a value of approximately 1.9-3.17 million yuan, and steam production value is approximately 2.5 million yuan. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model;

[0019] In the diagram: 2 high-temperature absorption tower, 5 high-temperature circulating pump tank, 6 high-temperature sulfuric acid pump, 7 first valve, 8 induced draft fan, 9 second valve, 10 gas phase balance pipe control valve. Detailed Implementation

[0020] Example 1:

[0021] like Figure 1 As shown, an apparatus for non-stop replacement of high-temperature sulfuric acid pumps includes a high-temperature circulating pump tank 5, an extraction device, and a gas phase balance pipe control valve 10. The high-temperature circulating pump tank 5 has a gas phase balance pipe interface at its top, and two high-temperature sulfuric acid pumps 6 are arranged side-by-side on the high-temperature circulating pump tank 5, with at least one being a standby pump. The extraction device includes an induced draft fan 8 and an induced draft pipe connected to the top of the high-temperature circulating pump tank 5 via a flange, as well as a first valve 7 at the inlet end and a second valve 9 at the outlet end of the induced draft pipe. The outlet end of the induced draft pipe is connected to a connecting pipe section between the outlet of the secondary absorption tower and the tail suction pipe. The gas phase balance pipe control valve 10 is installed on the gas phase balance pipe to block the gas communication between the high-temperature absorption tower and the high-temperature circulating pump tank 5.

[0022] Preferably, the inlet end of the induced draft fan 8 is connected to the opening at the top of the high-temperature circulating pump tank 5 through the first valve 7, and the outlet end is connected to the induced draft pipe through the second valve 9. The end of the induced draft pipe is connected to the negative pressure section from the outlet of the second suction tower to the tail suction pipe.

[0023] Preferably, a detachable figure-eight blind flange is provided between the first valve 7 and the second valve 9 to isolate the connection between the induced draft fan 8 and the high-temperature circulating pump tank 5.

[0024] Preferably, the two high-temperature sulfuric acid pumps 6 are configured as follows: one pump operates at 60%-70% of the maximum design flow rate, and the other pump serves as a backup; or both pumps operate simultaneously, with the total flow rate matching the design flow rate of a single pump.

[0025] Preferably, the induced draft fan 8 is a variable frequency centrifugal induced draft fan, whose motor frequency is adjustable to maintain the negative pressure state in the high temperature circulating pump tank 5.

[0026] Preferably, the gas phase balance pipe control valve 10 is a manual valve or an automatic control valve. When closed, it blocks the flue gas from the high-temperature absorption tower from entering the high-temperature circulating pump tank 5, while allowing external air to be supplied to the pump tank through the air extraction device.

[0027] Preferably, the connection point between the exhaust pipe and the outlet of the second suction tower to the tail suction pipe is located before the inlet of the tail suction tower, and the connection point is arranged at an angle downward to prevent liquid backflow.

[0028] Example 2:

[0029] The working principle of this patent is as follows:

[0030] Based on the existing high-temperature absorption tower 2, high-temperature circulating pump tank 5, and one circulating pump, a new negative pressure extraction device is added, namely components 7, 8, and 9 in the figure. A manual valve or control valve 10 is added to the gas phase balance pipe, and a high-temperature sulfuric acid pump 6 of the same specification is added to the circulating pump tank. The front and rear valves 7 and 9 on the negative pressure extraction device are normally closed. To ensure internal leakage of the valves, a figure-eight blind flange can be added in front of the valve. Before maintenance, the blind flange is removed, the valve is opened, and the induced draft fan is turned on. After normal operation, the faulty pump is disassembled, the pump tank pressure and remote pressure are checked, and the frequency converter of the induced draft fan motor is adjusted to maintain a negative pressure state. When opening the front and rear valves of the negative pressure extraction device, the valve on the gas phase balance pipe is closed to ensure that it is closed.

Claims

1. A device for replacing a high-temperature sulfuric acid pump without stopping the machine, characterized in that, It includes a high-temperature circulating pump tank (5), an extraction device, and a gas phase balance pipe control valve (10); the top of the high-temperature circulating pump tank (5) is provided with a gas phase balance pipe interface, and two high-temperature sulfuric acid pumps (6) are arranged side by side on the high-temperature circulating pump tank (5), of which at least one is a standby pump; the extraction device includes an induced draft fan (8) and an induced draft pipe connected to the top of the high-temperature circulating pump tank (5) by a flange, as well as a first valve (7) at the inlet end and a second valve (9) at the outlet end of the induced draft pipe; the outlet end of the induced draft pipe is connected to the connecting pipe section between the outlet of the second absorption tower and the tail suction pipe; the gas phase balance pipe control valve (10) is set on the gas phase balance pipe to block the gas communication between the high-temperature absorption tower and the high-temperature circulating pump tank (5).

2. The device for non-stop replacement of a high-temperature sulfuric acid pump according to claim 1, characterized in that, The inlet end of the induced draft fan (8) is connected to the opening at the top of the high temperature circulating pump tank (5) through the first valve (7), and the outlet end is connected to the induced draft pipe through the second valve (9). The end of the induced draft pipe is connected to the negative pressure section from the outlet of the second suction tower to the tail suction pipe.

3. The device for non-stop replacement of a high-temperature sulfuric acid pump according to claim 1, characterized in that, A detachable figure-eight blind flange is provided between the first valve (7) and the second valve (9) to isolate the connection between the induced draft fan (8) and the high-temperature circulating pump tank (5).

4. The device for non-stop replacement of a high-temperature sulfuric acid pump according to claim 1, characterized in that, The two high-temperature sulfuric acid pumps (6) are configured as follows: one pump operates at 60%-70% of the maximum designed flow rate, and the other pump is used as a backup; or both pumps operate simultaneously, with the total flow rate matching the design flow rate of a single pump.

5. The device for non-stop replacement of a high-temperature sulfuric acid pump according to claim 1, characterized in that, The induced draft fan (8) is a variable frequency centrifugal induced draft fan, whose motor frequency is adjustable to maintain the negative pressure state in the high temperature circulating pump tank (5).

6. The device for non-stop replacement of a high-temperature sulfuric acid pump according to claim 1, characterized in that, The gas phase balance pipe control valve (10) is a manual valve or an automatic control valve. When closed, it blocks the flue gas from the high-temperature absorption tower from entering the high-temperature circulating pump tank (5), while allowing external air to be supplied to the pump tank through the air extraction device.

7. The device for non-stop replacement of a high-temperature sulfuric acid pump according to claim 1, characterized in that, The connection point between the exhaust pipe and the outlet of the second suction tower to the tail suction pipe is located in front of the inlet of the tail suction tower, and the connection point is arranged at an angle downward to prevent liquid backflow.

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