Treatment system for phenolic waste gas

Abstract

The utility model discloses a treatment system for phenolic waste gas, and relates to the technical field of waste gas treatment systems. The device comprises a structured packing tower, an alkali liquor tank, a sewage treatment unit, a chimney and a connecting pipeline, the structured packing tower is connected with a waste gas connector through a pipeline; the structured packing tower is connected with the chimney after being connected with two groups of fans in parallel through pipelines; a liquid outlet in the bottom of the structured packing tower is communicated with an alkali liquor tank through a pipeline; the side part of the alkali liquor tank is connected with two groups of circulating pumps in parallel through pipelines and then is connected with a sprayer on the upper side in the structured packing tower. According to the utility model, the circulation volume is lower, and the contact area is larger, so that the power and the energy consumption of the required pump are lower, the provided contact area is larger, and a higher removal rate is obtained; open fire is not needed in the system, so that the system is safer and more reliable; two groups of fans, circulating pumps and liquid discharge pumps are used in the system, one group is used, and the other group is standby, so that overhaul and maintenance are facilitated.

Description

Technical Field

[0001] This utility model belongs to the technical field of waste gas treatment systems, and in particular relates to a treatment system for phenolic waste gas. Background Technology

[0002] Phenolic waste gas refers to waste gas containing phenolic compounds such as phenol, resorcinol, furanol, and naphthol. It is classified into large-breathing waste gas and small-breathing waste gas. Large-breathing waste gas refers to high-concentration organic gases containing phenolic compounds emitted when the liquid level in the storage tanks of transport vehicles such as chemical transport ships and tankers changes. Small-breathing waste gas refers to high-concentration organic gases containing phenolic compounds emitted when the temperature or pressure in the storage tanks or transport vehicles changes.

[0003] Currently, the main treatment methods for the tail gas of phenol storage and transportation include the following: (1) Activated carbon adsorption: using the abundant pores of activated carbon, under the action of van der Waals forces, organic gas molecules are adsorbed into the pores of activated carbon, thereby removing organic molecules; its disadvantages are that the service life of activated carbon is short and the replacement frequency is high; activated carbon reacts chemically with phenolic gases, which can easily lead to bed overheating and safety hazards; and a large amount of activated carbon hazardous waste will be generated, with high transportation and disposal costs; (2) Cryogenic technology: by compressing the refrigerant to form a phase change, a cryogenic environment is created, and organic gases condense into droplets through the cold trap, thereby reducing the concentration of organic gases; its disadvantages are that phenols are easy to crystallize, which will block the cryogenic channel, and the investment in cryogenic equipment is huge; transportation energy consumption and maintenance costs are high; (3) Activated carbon adsorption and desorption technology: using the abundant pores of activated carbon, under the action of van der Waals forces, organic gas molecules are adsorbed into the pores of activated carbon, thereby removing organic gas molecules; in the adsorption After saturation, high temperature is formed by steam to release the organic gas molecules adsorbed in the activated carbon; its disadvantage is that the removal rate is low and has a certain limit, and it is generally not possible to achieve a concentration of less than 1g / m³ for emission; the operating energy consumption is high and the operating noise is loud; phenols react on the activated carbon bed and are difficult to desorb; (4) Thermal oxidation technology: the temperature of phenolic gas is raised to above 400℃ by electric energy or natural gas combustion, so that it decomposes into carbon dioxide and water; the disadvantage is that the equipment investment is high, the operation requires natural gas or electricity, resulting in high operating costs; and it is an open flame equipment with certain safety hazards; (5) Traditional random packing scrubbing tower technology: using the acid-base washing principle, the alkaline solution is circulated, and the alkaline solution and phenolic waste gas form an acid-base neutralization reaction on the random packing, thereby removing phenolic organic gas; the disadvantage is that the circulation volume is large, the pump energy consumption is high, the random packing contact area is small, the removal efficiency is low, and the removal rate has a certain limit; a large amount of acid-base neutralized sodium phenolate wastewater and a large amount of alkaline solution are generated. Therefore, this technical solution proposes a treatment system for phenolic waste gas that does not use open flames, has low energy consumption, large contact area, and high removal efficiency. Utility Model Content

[0004] This invention provides a system for treating phenolic waste gas. It employs a structured packed tower as a scrubbing tower to treat high-concentration phenolic waste gas. Within the wastewater treatment unit, electrode plate oxidation technology is used to treat wastewater from the alkali tank, decomposing the wastewater into carbon dioxide and water. The resulting new alkali solution provides a circulating acid-base neutralization solution. Compared to conventional random packed towers, this system has a lower circulation volume and a larger contact area, thus requiring lower pump power and energy consumption, providing a larger contact area and achieving a higher removal rate. This system does not require open flames, making it safer and more reliable. Furthermore, the system is equipped with differential pressure detection to prevent phenolic sublimation and crystallization, which could block gas passages. In summary, this system solves the problems in the prior art.

[0005] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0006] This utility model discloses a treatment system for phenolic waste gas, comprising a structured packed tower, an alkali tank, a wastewater treatment unit, a chimney, and connecting pipelines.

[0007] The gas inlet at the lower side of the structured packed tower is connected to a gas inlet for receiving phenolic waste gas via a pipeline; the gas outlet at the top of the structured packed tower is connected to a chimney via two sets of fans connected in parallel via a pipeline; the liquid outlet at the bottom of the structured packed tower is connected to an alkali tank via a pipeline.

[0008] The side of the alkali tank is connected to an industrial water connector via a pipeline, and the bottom is connected to an alkali supply connector via a pipeline. The side is connected to two sets of circulating pumps in parallel via pipelines and then to a sprayer on the upper side inside the structured packed tower. The bottom of the alkali tank is also connected to two sets of discharge pumps in parallel via pipelines and then to a wastewater treatment unit. The wastewater treatment unit is equipped with electrode plates for oxidizing wastewater.

[0009] Furthermore, the bottom of the alkali tank is equipped with a condensate drain port with a manual ball valve, the upper part is equipped with a temperature transmitter, a pH meter, a tuning fork switch and a drain pipe, and the side is equipped with a magnetic level gauge.

[0010] Furthermore, a flow meter is installed on the main pipeline between the two sets of circulating pumps and the sprayers.

[0011] Furthermore, a circulation secondary pipe with a manual ball valve is installed between the flow meter and the alkali tank.

[0012] Furthermore, a drain pipe with a manual ball valve is installed between the bottom of the alkali tank and the wastewater treatment unit.

[0013] Furthermore, manual ball valves, pressure gauges, check valves, and Y-type filters are installed on the pipelines of the circulation pump and the discharge pump.

[0014] Furthermore, a differential pressure gauge is installed on the side of the structured packed tower.

[0015] Furthermore, a pressure gauge, a pneumatic ball valve, and a manual ball valve are installed on the pipeline between the industrial water connector and the alkali tank; a pneumatic ball valve and a manual ball valve are installed on the pipeline between the alkali supply connector and the alkali tank.

[0016] The present invention has the following advantages over the prior art:

[0017] (1) A structured packed tower is used as a scrubbing tower to treat high-concentration phenolic waste gas. Electrode plate oxidation technology is used in the wastewater treatment unit to treat wastewater from the alkaline tank, decomposing the wastewater into carbon dioxide and water. The new alkaline solution formed can provide circulating acid-base neutralization.

[0018] (2) Compared with conventional random packed towers, the circulation volume is lower and the contact area is larger, thus requiring lower pump power and energy consumption, providing a larger contact area and achieving a higher removal rate;

[0019] (3) No open flame is required in the system, making it safer and more reliable. In addition, the system is equipped with differential pressure detection, which can prevent phenols from sublimating and crystallizing, thus preventing blockage of gas passages.

[0020] (4) The system is equipped with manual ball valves and pneumatic ball valves to facilitate pipeline control. The system also uses two sets of fans, circulating pumps and drainage pumps, one for use and one for standby, which facilitates inspection and maintenance and ensures continuous operation.

[0021] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a phenolic waste gas treatment system according to the present invention;

[0024] The attached diagram lists the components represented by each number as follows:

[0025] 1-Structured packed tower, 11-Differential pressure gauge, 12-Sprayer, 13-Exhaust gas connector, 14-Flow meter, 15-Circulation auxiliary pipe, 2-Alkali tank, 21-Temperature transmitter, 22-pH meter, 23-Tuning fork switch, 24-Magnetic level gauge, 25-Drain pipe, 26-Pressure gauge, 27-Condensate drain, 28-Industrial water connector, 29-Alkali supply connector, 3-Chimney, 4-Sewage treatment unit, 41-Drain auxiliary pipe, 5-Circulation pump, 51-Y-type filter, 52-Check valve, 6-Fan, 7-Drain pump. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0027] In the description of this utility model, it should be understood that the terms "below", "side", "top", "bottom", "inner", "upper side", etc., which indicate orientation or positional relationship, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0028] Please see Figure 1 As shown, a system for treating phenolic waste gas according to this utility model includes a structured packed tower 1, an alkali tank 2, a wastewater treatment unit 4, a chimney 3, and connecting pipelines.

[0029] The structured packed tower 1 is an existing device. A sprayer is installed at the top, and packing is installed inside by a support. Below the packing is a grid plate. The bottom of the structured packed tower 1 has a liquid storage space. The alkaline solution in the alkaline solution tank 2 is pumped into the sprayer by the circulating pump 5. Phenolic waste gas enters from the gas inlet and gradually rises through the packing. Under the action of the sprayed alkaline solution, an acid-base neutralization reaction is carried out. The wastewater generated is connected to the alkaline solution tank 2 through the bottom pipeline of the structured packed tower 1.

[0030] The gas inlet at the lower side of the structured packed tower 1 is connected to a gas inlet 13 for receiving phenolic waste gas via a pipeline; the gas outlet at the top of the structured packed tower 1 is connected to two sets of fans 6 in parallel via pipelines and then connected to the chimney 3; the liquid outlet at the bottom of the structured packed tower 1 is connected to the alkali tank 2 via a pipeline; the gas inlet 13 for receiving phenolic waste gas can be installed on the upper part of the storage tank of a ship transporting industrial products in the port, and is used to receive high-concentration organic gas containing phenolic compounds emitted due to changes in the liquid level in the storage tanks of transport ships, transport tanks and other transport vehicles. Of course, the application of receiving high-concentration phenolic compounds in other scenarios also meets the application requirements of this solution.

[0031] As in one embodiment:

[0032] Phenolic waste gases, such as phenol;

[0033] Gas inlet concentration: phenolic organic waste gas <5000 mg / m³; temperature: -5~40℃; flow rate <10000 m³; gas operating pressure <0.1 MPa(G) (0.1 MPa=100 kPa); structured packed tower dimensions: φ200~2000 mm; height 10000 mm; organized emission concentration: phenolic organic waste gas <20 mg / m³ (according to DB31-933-2015 Shanghai Municipal Integrated Emission Standard for Air Pollutants).

[0034] For example, in a storage and transportation unit, when storing liquid phenol at 40 degrees Celsius, the actual measured concentration of organic gas is approximately 1 g / m³. When the phenol is loaded onto the truck, the liquid flow rate is approximately 40 m³ / h, so the flow rate of the high-concentration gas is also 40 m³ / h. After acid and alkali washing in a structured packed tower, the circulation rate is only 300 kg / h, and the overall energy consumption does not exceed 3 kW. The stable discharge at the outlet is below 20 mg / m³. Wastewater is treated through an electrode plate oxidation wastewater treatment system, achieving the above-mentioned results.

[0035] According to actual calculations, the circulation volume of structured packed towers is only 1 / 10 of that of random packed towers, and the pump power is theoretically only 1 / 10 of that of random packed towers, resulting in lower energy consumption. The contact area of ​​structured packed towers is 10 times that of random packed towers, resulting in higher removal efficiency, up to 99%, which is far higher than the 95% removal rate of typical random packed towers.

[0036] The side of the alkali tank 2 is connected to the industrial water connector 28 via a pipeline, and the bottom is connected to the alkali supply connector 29 via a pipeline. The side is connected to two sets of circulating pumps 5 in parallel via pipelines and then to the sprayer 12 on the upper side inside the structured packed tower 1. The bottom of the alkali tank 2 is also connected to two sets of drain pumps 7 in parallel via pipelines and then to the wastewater treatment unit 4. The wastewater treatment unit 4 is equipped with electrode plates for oxidizing wastewater. The industrial water connector 28 is used to provide the water required for preparing the alkali solution in the alkali tank 2. The alkali supply connector 29 is used to provide the alkali solution required for preparing the alkali solution in the alkali tank 2. The alkali solution is such as sodium hydroxide. The wastewater treatment unit 4 uses electrode plate oxidation technology to treat sodium phenolate wastewater, decomposing sodium phenolate into CO2 and H2O, generating new OH-, forming a new alkali solution (taking NaOH as an example) for circulating acid-base neutralization.

[0037] The alkali tank 2 has a drain outlet 27 with a manual ball valve installed at the bottom via a pipeline. A temperature transmitter 21, a pH meter 22, a tuning fork switch 23, and a drain pipe 25 are installed at the top. A magnetic level gauge 24 is installed on the side, providing clear liquid level information for effective monitoring and control of the liquid level within the container. The temperature transmitter 21 converts temperature variables into a standardized, transmittable signal for monitoring and control by the control system. The pH meter 22 monitors the pH of the substance and converts it into a standardized, transmittable signal for monitoring and control by the control system. The tuning fork switch 23 accurately detects the liquid level. The drain pipe 25 discharges wastewater from the alkali tank 2 into a ditch after cleaning, and the end of the drain pipe 25 is connected to the ditch.

[0038] Among them, a flow meter 14 is installed on the main pipeline between the two sets of circulating pumps 5 and the sprayer 12. The flow meter 14 is used to measure the flow rate of the fluid in the pipeline. The two sets of circulating pumps 5, the drain pump 7 and the fan 6 are all used in a one-to-one standby configuration, which facilitates inspection and maintenance and ensures continuity.

[0039] A circulation secondary pipe 15 with a manual ball valve is installed between the flow meter 14 and the alkali tank 2; a discharge secondary pipe 41 with a manual ball valve is installed between the bottom of the alkali tank 2 and the sewage treatment unit 4; both the circulation secondary pipe 15 and the discharge secondary pipe 41 are reserved based on the pipe design angle to ensure safety and backup pipelines.

[0040] The circulating pump 5 and the discharge pump 7 are equipped with manual ball valves, pressure gauges 26, check valves 52 and Y-type filters 51 for pipeline filtration; the pressure gauges are used to monitor pump pressure and the check valves 52 are used to prevent loops.

[0041] Among them, a differential pressure gauge 11 is installed on the side of the structured packed tower 1. The differential pressure gauge 11 is used to measure the pressure difference between the two ends of the pipeline or equipment.

[0042] The pipeline between the industrial water connector 28 and the alkali tank 2 is equipped with a pressure gauge 26, a pneumatic ball valve, and a manual ball valve; the pipeline between the alkali supply connector 29 and the alkali tank 2 is equipped with a pneumatic ball valve and a manual ball valve.

[0043] This technical solution uses a structured packed tower as a scrubbing tower to treat high-concentration phenolic waste gas. The wastewater treatment unit utilizes electrode plate oxidation technology to treat wastewater from the alkali tank, decomposing the wastewater into carbon dioxide and water. The resulting new alkali solution provides a circulating acid-base neutralization solution. Compared to conventional random packed towers, this solution has a lower circulation volume and a larger contact area, thus requiring lower pump power and energy consumption, providing a larger contact area and achieving a higher removal rate. The system does not require open flames, making it safer and more reliable. Furthermore, the system is equipped with differential pressure detection to prevent phenolic sublimation and crystallization, which could block gas passages. The system includes manual and pneumatic ball valves for easy pipeline control. Additionally, two sets of fans, circulating pumps, and drainage pumps are used in the system, one for operation and one for backup, facilitating maintenance and ensuring continuous operation.

[0044] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it. This utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A treatment system for phenolic off-gas, characterized by, The rectifying filler tower (1), the lye tank (2), the sewage treatment unit (4), the chimney (3) and the connecting pipeline are included. The waste gas joint (13) for receiving phenolic waste gas is connected by pipeline at the gas inlet of the lower side of the rectifying filler tower (1); two groups of fans (6) are connected by pipeline in parallel at the gas outlet of the top of the rectifying filler tower (1) and are connected with the chimney (3) after the fans (6); the liquid outlet at the bottom of the rectifying filler tower (1) is connected by pipeline with the lye tank (2). The side of the lye tank (2) is connected by pipeline with the industrial water joint (28), the bottom is connected by pipeline with the lye supply joint (29), the side is connected by pipeline in parallel with two groups of circulating pumps (5) and is connected with the sprayer (12) at the upper side inside the rectifying filler tower (1); the bottom of the lye tank (2) is also connected by pipeline in parallel with two groups of liquid discharge pumps (7) and is connected with the sewage treatment unit (4), and the sewage treatment unit (4) is provided with electrode plates for oxidizing the waste water.

2. The system for treating phenolic waste gas according to claim 1, wherein The bottom of the lye tank (2) is provided with a condensate discharge port (27) with a manual ball valve by pipeline, the upper part is provided with a temperature transmitter (21), a pH meter (22), a tuning fork switch (23) and a liquid discharge pipe (25), and the side is provided with a magnetic reed liquid level meter (24).

3. The system for treating phenolic exhaust gas according to claim 1, wherein Flow meters (14) are installed on the main pipelines between the two groups of circulating pumps (5) and the sprayers (12).

4. The system for treating phenolic exhaust gas according to claim 3, wherein Circulating sub-pipes (15) with manual ball valves are installed between the flow meters (14) and the lye tank (2).

5. The system for treating phenolic exhaust gas according to claim 1, wherein Liquid discharge sub-pipes (41) with manual ball valves are installed between the bottom of the lye tank (2) and the sewage treatment unit (4).

6. The system for treatment of phenolic waste gas according to claim 1, wherein Manual ball valves, pressure gauges (26), check valves (52) and Y-type filters (51) are installed on the pipelines of the circulating pumps (5) and the liquid discharge pumps (7).

7. The system for treatment of phenolic waste gas according to claim 1, wherein Pressure difference gauges (11) are installed on the sides of the rectifying filler tower (1).

8. The system for treatment of phenolic waste gas according to claim 1, wherein Pressure gauges (26), pneumatic ball valves and manual ball valves are installed on the pipelines between the industrial water joint (28) and the lye tank (2); pneumatic ball valves and manual ball valves are installed on the pipelines between the lye supply joint (29) and the lye tank (2).

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