Smelting flue gas desulfurization and denitrification wastewater treatment device

Abstract

The utility model belongs to the technical field of organic amine desulfurization and acid making, and discloses a smelting flue gas desulfurization and denitrification wastewater treatment device which comprises a washing tower, a cooling packing tower, an amine liquid desulfurization and acid making system and a desulfurization and denitrification tower which are sequentially connected through a pipeline, and a desulfurization and denitrification tower circulating pipeline is arranged at the lower part of the desulfurization and denitrification tower; the desulfurization and denitrification tower circulating pipeline is provided with a desulfurization and denitrification tower circulating pump and is connected with a desulfurization and denitrification tower wastewater discharge branch pipe and a desulfurization and denitrification tower wastewater recovery branch pipe, and the desulfurization and denitrification tower wastewater discharge branch pipe and the desulfurization and denitrification tower wastewater recovery branch pipe are respectively provided with an electric switching valve; and the desulfurization and denitrification tower wastewater recovery branch pipe is connected with a desulfurization and denitrification tower wastewater spray head arranged in the cooling packed tower. According to the device, SO2 in the desulfurization and denitrification tower wastewater is recycled, and pollution and equipment corrosion caused by subsequent treatment of the wastewater are avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of organic amine desulfurization and acid production, and particularly relates to a smelting flue gas desulfurization and denitrification wastewater treatment device. Background Art

[0002] Since the wet organic amine desulfurization process is a renewable amine process, it has the characteristics of being able to recycle the absorbed amine liquid, recovering sulfur resources to make acid, and having little secondary pollution. Therefore, the treatment of flue gas from recycled lead smelting usually adopts organic amine desulfurization technology, and combines it with an ozone denitrification system to meet the flue gas treatment requirements and achieve stable tail gas emissions that meet standards. In the existing technology, the smelting flue gas is first cooled in a cooling packed tower, and then desulfurized by an amine liquid desulfurization and acid production system. Generally, ozone is introduced and then treated in a desulfurization and denitrification tower, and the generated wastewater is discharged into the wastewater treatment system. However, the smelting flue gas after desulfurization by the amine liquid desulfurization and acid production system will still contain a small amount of SO2 and NO due to factors such as amine liquid adsorption saturation and thermal decomposition. X Flue gas, resulting in SO2, NO X The decomposition of sulphurous acid produces large amounts of wastewater, and the decomposition of sulphurous acid produces wastewater containing SO2. The pollution control of this type of wastewater requires additional waste gas treatment facilities, which in turn causes corrosion of on-site equipment. Therefore, there is an urgent need to optimize the structure of existing smelting flue gas amine liquid desulfurization and denitrification treatment equipment to achieve the reuse of SO2 in the desulfurization and denitrification tower wastewater, thereby avoiding pollution and equipment corrosion caused by subsequent wastewater treatment. Utility Model Content

[0003] The utility model aims to solve the problems in the background technology and provides a smelting flue gas desulfurization and denitrification wastewater treatment device, which can realize the reuse of SO2 in the desulfurization and denitrification tower wastewater and avoid pollution and equipment corrosion caused by subsequent wastewater treatment.

[0004] To achieve the above objectives, the technical solutions of this utility model are as follows:

[0005] A smelting flue gas desulfurization and denitrification wastewater treatment device comprises a washing tower, a cooling packing tower, an amine liquid desulfurization and acid production system and a desulfurization and denitrification tower connected in sequence by pipelines, characterized in that a desulfurization and denitrification tower circulation pipeline is provided at the lower part of the desulfurization and denitrification tower, a desulfurization and denitrification tower circulation pipeline is provided with a desulfurization and denitrification tower circulation pump, and is connected to a desulfurization and denitrification tower wastewater discharge branch pipe and a desulfurization and denitrification tower wastewater recovery branch pipe, the desulfurization and denitrification tower wastewater discharge branch pipe and the desulfurization and denitrification tower wastewater recovery branch pipe are respectively provided with electric switching valves, and the desulfurization and denitrification tower wastewater recovery branch pipe is connected to a desulfurization and denitrification tower wastewater spray head arranged in the cooling packing tower.

[0006] Preferably, a cooling packing tower circulation pipe is connected to the lower part of the cooling packing tower, and a cooling packing tower circulation pump and a plate heat exchanger are provided on the cooling packing tower circulation pipe, and the cooling water spray head is connected to the upper end of the cooling packing tower.

[0007] Preferably, an upper packing layer and a lower packing layer are spaced apart from each other from top to bottom in the cooling packing tower, the wastewater spray pipe is located between the upper packing layer and the lower packing layer, and the cooling water spray head is located above the upper packing layer.

[0008] Preferably, an automatic exhaust valve is provided on the circulation pipe of the cooling packing tower, and the automatic exhaust valve is located on the upper side of the upstream horizontal pipe of the plate heat exchanger.

[0009] Preferably, a liquid level meter and a pH detection probe are provided below the flue gas inlet of the desulfurization and denitrification tower.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] (1) The wastewater from the desulfurization and denitrification tower of the utility model is first discharged into a cooling packed tower to react with dilute sulfuric acid to form SO2, which enters the flue gas and is absorbed by the amine desulfurization tower of the amine desulfurization and acid production system, and then produces sulfuric acid through the acid production system. This not only utilizes the SO2 decomposed by the desulfurization and denitrification wastewater, but also solves the SO2 pollution and equipment corrosion in wastewater treatment. The SO2 in the desulfurization and denitrification wastewater can be used to return about 300 tons of sulfuric acid annually, effectively reducing raw material costs and improving economic benefits.

[0012] (2) The utility model solves the SO2 gas turbidity problem by arranging an automatic exhaust valve on the horizontal pipe at the rear side of the circulating pump of the cooling packing tower, thereby achieving good heat exchange and circulation of the plate heat exchanger;

[0013] (3) The desulfurization and denitrification wastewater of the utility model enters the cooling packing tower below the cooling water spray head and the upper packing layer, which enhances the decomposition speed and effect of SO2 in the wastewater and can achieve the secondary discharge of wastewater without sulfur dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings.

[0015] Figure 1 This is a schematic diagram of the structure of the utility model;

[0016] In the figure: 1. Scrubber, 2. Cooling packed tower, 3. Amine liquid desulfurization and acid production system, 4. Desulfurization and denitrification tower, 5. Desulfurization and denitrification tower circulation pipeline, 6. Desulfurization and denitrification tower circulation pump, 7. Desulfurization and denitrification tower wastewater discharge branch pipe, 8. Desulfurization and denitrification tower wastewater recovery branch pipe, 9. Electric switching valve, 10. Cooling packed tower wastewater spray head, 11. Cooling packed tower circulation pipe, 12. Cooling packed tower circulation pump, 13. Plate heat exchanger, 14. Cooling water spray head, 15. Upper packing layer, 16. Lower packing layer, 17. Automatic exhaust valve, 18. Electrostatic demister, 19. Booster fan, 20. Liquid level gauge, 21. pH detection probe. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0018] In the description of the present invention, it should be understood that the terms "middle", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0019] In this utility model, unless otherwise specified or limited, the terms "disposed," "installed," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed or detachable connections, mechanical connections, direct connections, or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0020] like Figure 1As shown, a smelting flue gas desulfurization and denitrification wastewater treatment device includes a washing tower 1, a cooling packing tower 2, an amine liquid desulfurization and acid production system 3 and a desulfurization and denitrification tower 4 connected in sequence by pipelines. A desulfurization and denitrification tower circulation pipeline 5 is provided at the lower part of the desulfurization and denitrification tower. A desulfurization and denitrification tower circulation pipeline is provided with a desulfurization and denitrification tower circulation pump 6, and is connected to a desulfurization and denitrification tower wastewater discharge branch pipe 7 and a desulfurization and denitrification tower wastewater recovery branch pipe 8. The desulfurization and denitrification tower wastewater discharge branch pipe and the desulfurization and denitrification tower wastewater recovery branch pipe are respectively provided with an electric switching valve 9. A liquid level meter 20 and a pH detection probe 21 are provided below the flue gas inlet of the desulfurization and denitrification tower, which are connected to the control system of the entire smelting flue gas desulfurization and denitrification wastewater treatment device. According to the monitoring of the wastewater liquid level height and pH in the desulfurization and denitrification tower, the electric switching valve 9 on the desulfurization and denitrification tower wastewater discharge branch pipe and the desulfurization and denitrification tower wastewater recovery branch pipe are controlled to open and close, thereby adjusting the flow direction of the desulfurization and denitrification tower wastewater. The wastewater recovery branch pipe of the desulfurization and denitrification tower is connected to the desulfurization and denitrification tower wastewater spray head 10 arranged in the cooling packed tower. The cooling packed tower is provided with an upper packing layer 15 and a lower packing layer 16 from top to bottom. The wastewater spray pipe is located between the upper packing layer and the lower packing layer, which can make the wastewater recovered from the desulfurization and denitrification tower react with the dilute acid wastewater flowing down from the upper part of the cooling packed tower. The sodium sulfite is decomposed into SO2 under the action of dilute sulfuric acid, and enters the amine liquid desulfurization and acid production system (existing technology, which will not be repeated here) along with the flue gas. The tail gas (a small amount of SO2) of the acid production system returns to the cooling packed tower and is discharged after a series of treatments.

[0021] The cooling tower wastewater spray head 10 is composed of a 316L pipe connected to a 316L spiral nozzle, with at least 20 spiral nozzles. A cooling tower circulation pipe 11 is connected to the lower portion of the cooling tower. This pipe is equipped with a cooling tower circulation pump 12 and a plate heat exchanger 13. It is also connected to a cooling water spray head 14 located at the upper end of the cooling tower. The cooling water spray head is located above the upper packing layer, enabling the cooling tower's cooling water to be recycled. The plate heat exchanger cools the circulating water. A DN20 316L stainless steel automatic exhaust valve 17 is installed on the cooling tower circulation pipe. The automatic exhaust valve is located on the upper side of the upstream horizontal pipe of the plate heat exchanger, that is, between the plate heat exchanger's water inlet and the cooling tower circulation pump. The automatic exhaust valve is a one-way valve that can solve the problem of dilute acid wastewater and desulfurization and denitrification wastewater forming SO2 gas turbidity in the cooling tower circulation pump 11, preventing it from passing through the plate heat exchanger 13. During actual production, when the discharge level of the cooling tower is low, fresh water must be added from the water replenishment port below the cooling tower's air inlet to ensure proper operation. This is conventional technology and will not be further described. A two-stage electrostatic demister 18 and a booster fan 19 are installed between the cooling tower and the amine desulfurization and acid production system to remove acid mist and metal dust from the flue gas, preventing it from interfering with the subsequent amine desulfurization and acid production.

[0022] The working principle of this utility model is as follows:

[0023] like Figure 1 As shown, the flue gas from the recycled lead smelting industry first passes through a scrubber 1 for dust removal and initial cooling, then through a cooling packed tower 2 for further cooling. Acid mist and metal dust are removed by a two-stage electrostatic demister 18. Under the action of a booster fan 19, the flue gas enters the amine desulfurization and acid production system for desulfurization. After ozone is introduced, the flue gas enters the desulfurization and denitrification tower 4 for treatment. A desulfurization and denitrification tower wastewater recovery branch pipe 8 and an electric switching valve 9 are added to the desulfurization and denitrification tower circulation pipeline 5. The wastewater is transported to the cooling packed tower 2 via a DN50-80mm PVC desulfurization and denitrification tower wastewater recovery branch pipe 8. A cooling packed tower wastewater spray head 10 is installed below the upper packing layer 15 inside the cooling packed tower 2 to allow the wastewater to react with the dilute acid wastewater flowing down from above. The sodium sulfite is decomposed into SO2 by the dilute sulfuric acid. This SO2, along with the flue gas, passes through the two-stage electrostatic demister 18 and the booster fan 19, then enters the amine desulfurization and acid production system 3 for absorption, ultimately entering the one-absorption-one-conversion acid production system to produce refined sulfuric acid. After stopping the addition of desulfurization and denitrification wastewater for 2 hours and waiting for all the SO2 in the wastewater to be released completely, the electric switching valve 7 on the desulfurization and denitrification tower wastewater discharge branch pipe is opened to discharge the wastewater into the wastewater treatment system for treatment.

[0024] The utility model forms an internal circulation in the desulfurization and denitrification tower 4, the desulfurization and denitrification tower circulating pump 6 and the desulfurization and denitrification tower wastewater spray head 10, and absorbs the flue gas SO2, NO X . A desulfurization and denitrification tower wastewater discharge branch pipe 7 and a desulfurization and denitrification tower wastewater recovery branch pipe 8 are provided on the desulfurization and denitrification tower circulation pipeline 5, and an electric switching valve 9 is provided on each branch pipe to facilitate timely discharge of liquid to the cooling packed tower through remote control. When the liquid level of the desulfurization and denitrification tower is close to the flue gas inlet and the pH reaches 7, the electric switching valve of the desulfurization and denitrification tower wastewater recovery branch pipe 8 should be opened remotely to discharge the desulfurization and denitrification wastewater to the cooling packed tower through the desulfurization and denitrification tower wastewater recovery branch pipe 8; otherwise, the electric switching valve on the desulfurization and denitrification tower wastewater discharge branch pipe 7 is opened to drain the water to the wastewater treatment system.

[0025] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments and that the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from all perspectives, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that come within the meaning and range of equivalents of the claims be included in the present invention.

Claims

1. A smelting flue gas desulfurization and denitrification wastewater treatment device, comprising a washing tower, a cooling packing tower, an amine liquid desulfurization and acid production system, and a desulfurization and denitrification tower connected in sequence by pipelines, characterized in that: A desulfurization and denitrification tower circulation pipeline is provided at the lower part of the desulfurization and denitrification tower, and a desulfurization and denitrification tower circulation pump is provided on the desulfurization and denitrification tower circulation pipeline, and is connected to a desulfurization and denitrification tower wastewater discharge branch pipe and a desulfurization and denitrification tower wastewater recovery branch pipe. The desulfurization and denitrification tower wastewater discharge branch pipe and the desulfurization and denitrification tower wastewater recovery branch pipe are respectively provided with electric switching valves, and the desulfurization and denitrification tower wastewater recovery branch pipe is connected to the desulfurization and denitrification tower wastewater spray head arranged in the cooling packing tower.

2. The smelting flue gas desulfurization and denitrification wastewater treatment device according to claim 1, characterized in that: The lower part of the cooling packing tower is connected to a cooling packing tower circulation pipe, which is provided with a cooling packing tower circulation pump and a plate heat exchanger and is connected to a cooling water spray head provided at the upper end of the cooling packing tower.

3. The smelting flue gas desulfurization and denitrification wastewater treatment device according to claim 2, characterized in that: An upper packing layer and a lower packing layer are arranged in the cooling packing tower from top to bottom, the wastewater spray pipe is located between the upper packing layer and the lower packing layer, and the cooling water spray head is located above the upper packing layer.

4. The smelting flue gas desulfurization and denitrification wastewater treatment device according to claim 2, characterized in that: An automatic exhaust valve is provided on the circulation pipe of the cooling packing tower, and the automatic exhaust valve is located on the upper side of the upstream horizontal pipe of the plate heat exchanger.

5. The smelting flue gas desulfurization and denitrification wastewater treatment device according to claim 1, characterized in that: A liquid level meter and a pH detection probe are provided below the flue gas inlet of the desulfurization and denitrification tower.

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