A high temperature odour pretreatment system

Abstract

The application discloses a high-temperature odor pretreatment system, which is characterized by high temperature and condensate discharge, and is pretreated, combined with normal-temperature odor and then introduced into an odor treatment facility, and can be applied to different project working scenes. The application is provided with twice gas-liquid separation, which ensures complete and thorough condensate discharge in high-temperature odor, avoids reduced odor pipeline flux caused by incomplete condensate discharge and avoids possible safety problems. The application collects and transports a large amount of condensate possibly generated in the pipeline through the measures of increasing baffles and condensate packages in the pipeline. The odor is locally changed in airflow direction and flow rate when passing through the baffles, and gas-liquid separation is realized under the action of inertia and turbulence. The scheme is simple and easy to implement and manage, and has a relatively remarkable effect on odor condensate discharge in actual operation.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, specifically to a high-temperature odor pretreatment system. Background Technology

[0002] In the treatment of wastewater from petrochemical enterprises, pretreatment processes such as oil-water flotation and biochemical treatment generate odor pollutants. These pollutants include organic compounds (VOCs) that participate in atmospheric photochemical reactions. With increasingly stringent environmental protection standards, there are clear regulations regarding the fugitive emissions of these substances. At 100mm above the open liquid surface of wastewater storage and treatment facilities containing VOCs, if the VOCs concentration is ≥200μmol / mol, a fixed cover is typically used to collect the odor. Different treatment methods are employed depending on the VOCs concentration in the odor, and only after treatment to meet standards can the odor be discharged.

[0003] Therefore, odor collection and treatment has become an indispensable part of the wastewater treatment process. Typically, newly built wastewater collection and treatment facilities (pretreatment and biological treatment stages) will have odor collection ports installed at the top. The odor enters the odor pipeline through the collection port and is then transported to the odor treatment facility for treatment.

[0004] However, for high-temperature odors generated in some special water treatment processes, such as the Fenton reaction, which uses hydrogen peroxide and ferrous salts for strong oxidation to reduce high COD in water, it is particularly suitable for treating organic wastewater that is difficult to biodegrade or treat using general chemical methods. Because the violent reaction releases a large amount of heat, the wastewater and the resulting odors can sometimes reach temperatures close to 100°C. Most wastewater treatment structures, however, operate at ambient temperature, and the odors they generate are also at ambient temperature. Due to the significant temperature difference between ambient and high-temperature odors, directly combining and collecting them poses certain risks and adversely affects downstream odor treatment facilities. However, collecting and treating this high-temperature odor separately would require additional land and investment.

[0005] In addition, the condensate produced by high-temperature odors can also impact the entire odor collection system. Especially in cold northern regions, sudden temperature changes can cause a large amount of condensate to accumulate in the odor pipes, thus affecting the flow of odors in the pipes. Conventional odor condensation removal measures cannot meet the discharge capacity of this condensate. If the condensate cannot be completely discharged from the odor transport pipes for a long time, pressure fluctuations will occur at the upstream odor collection points, which may even lead to safety accidents in severe cases.

[0006] Chinese patent CN106839796A discloses an odor heat exchange and condensation system and method, including: a heat exchange condenser, a temperature sensor, a biological deodorization device, a detection and control device, an odor collection pipe, and an odor exhaust pipe. This invention uses a newly developed heat exchange condenser to exchange heat with high-temperature odorous gas through air cooling, achieving a high degree of automation. However, it also has the characteristics of high cost and high energy consumption. In addition, the odorous gas generated by petrochemical enterprises may contain hydrocarbons, and using air cooling for heat exchange poses certain safety risks. Therefore, using this method for the pretreatment of high-temperature odorous gas is not economical, and its safety needs to be considered.

[0007] Chinese patent CN215981416U discloses an automatic condensate drainage device for pipelines in the petrochemical industry, comprising a diversion system, a liquid reservoir system, and a condensate drainage system. While the device is simple in structure and highly practical, it lacks a water seal between the condensate drainage pipeline and the sewage system when used for condensate drainage in odorous gas pipelines. Furthermore, it only uses one liquid reservoir in the entire odorous gas pipeline system. For large-scale odorous gas pipeline systems with a large coverage area, a single liquid reservoir cannot meet the condensate drainage needs of the entire network. Therefore, this device is not entirely suitable for the condensate drainage treatment of high-temperature odorous gases in petrochemical enterprises.

[0008] Therefore, exploring a system that can collect and treat high-temperature odors in an energy-efficient and economical way can not only improve the whole-process treatment scheme of this type of wastewater treatment measures, but also strengthen the safety guarantee in the production process, which has important practical application significance. Summary of the Invention

[0009] In response to the problems existing in the collection and treatment of high-temperature odors, this invention provides a high-temperature odor pretreatment system from the perspectives of quality safety and economic feasibility, aiming to achieve the safe transport of high-temperature odors and ensure their proper treatment throughout the entire wastewater treatment process.

[0010] The present invention provides a high-temperature odor pretreatment system, comprising an odor collection system, a high-temperature odor conveying pipeline, an odor heat exchanger, a normal-temperature odor conveying pipeline, and a liquid separator connected in sequence; the odor collection system comprises an odor collection port, a flame arrestor single-call valve, and a flame arrester connected in sequence.

[0011] Preferably, it also includes a condensate drainage device, which includes a condensate drainage baffle, a condensate bag, a condensate conveying pipeline, and a condensate collection well. The condensate drainage baffle is installed inside the high-temperature odor conveying pipeline, the condensate bag is installed at the bottom of the high-temperature odor conveying pipeline, and the condensate conveying pipeline is connected to the condensate bag to deliver the condensate to the condensate collection well.

[0012] Preferably, a water trap is installed on the condensate conveying pipeline.

[0013] Preferably, the odor heat exchanger adopts a tubular water-cooled heat exchange type.

[0014] Preferably, a regulating valve is installed on the high-temperature odor transmission pipeline, and a temperature transmitter is installed on the normal-temperature odor transmission pipeline. The regulating valve and the temperature transmitter are interlocked.

[0015] Preferably, a pressure gauge is installed on the ambient temperature odor delivery pipeline, and a level gauge is installed on the liquid separator.

[0016] Preferably, the high-temperature odor delivery pipeline is equipped with a scalding-proof layer.

[0017] Preferably, nitrogen gas is introduced into the separator to seal it, so that a slightly positive pressure is maintained inside the separator.

[0018] Odor collection outlets are located on the top of each sewage treatment structure. High-temperature odor generated inside the structure is discharged through the odor collection outlets and enters the high-temperature odor transport pipeline through the flame arrestor single-call valve and flame arrestor. The pipeline is equipped with anti-scalding measures.

[0019] The high-temperature odors generated by various structures are collected in the high-temperature odor transport pipeline and then discharged into the odor heat exchanger. After heat exchange, the temperature of the high-temperature odors drops to below 40°C. The cooled odors are then sent to the liquid separator through the ambient temperature odor transport pipeline. In the liquid separator, gas-liquid separation is carried out. The odors after condensation are connected to the ambient temperature odor pipeline network and enter the downstream treatment facilities for further treatment together with the ambient temperature odors. The separated condensate is sent to the condensate collection system.

[0020] When the high-temperature odorous gas passes through the condensate discharge baffle in the high-temperature odorous gas conveying pipeline, the airflow direction is changed, thereby promoting gas-liquid separation. The condensate is collected into the condensate bag under the action of gravity, and then transported to the condensate collection well equipped with a water seal safety device through the condensate conveying pipeline set under the condensate bag, and then discharged into the subsequent treatment facilities.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. This system is flexible and cost-effective. This invention primarily addresses the characteristics of high-temperature odors—high temperature and high condensation—by pre-treating them. The pre-treated odors can then be combined with ambient-temperature odors before entering the odor treatment facility. It can be applied to various project scenarios. In new projects, the high-temperature odor pre-treatment system can be integrated into the entire odor treatment process, shortening the treatment time and saving investment and land area. In renovation projects, only a high-temperature odor pre-treatment section needs to be added to the original treatment process. The cooled and condensed high-temperature odors can be combined with ambient-temperature odors for collection, without affecting the original odor treatment scale and facilities, achieving truly homogeneous treatment.

[0023] 2. Two-stage gas-liquid separation ensures complete condensation removal. This invention employs a dual-treatment approach to address the condensation problem. The entire pretreatment process involves two gas-liquid separations: the first in the delivery pipeline and the second at the separator. This ensures complete and thorough condensation removal from the high-temperature odorous gas, preventing reduced gas flow in the pipeline due to incomplete condensation and mitigating potential safety issues.

[0024] 3. The addition of a condensate drainage device to the pipeline is a simple and effective solution. This invention collects and transports large amounts of condensate that may be generated in the pipeline by adding baffles and condensate traps. This measure can be considered an optimization of high-temperature odor transport pipelines, requiring no land or energy. When odorous gas passes through the baffles, the airflow direction and velocity are locally altered, achieving gas-liquid separation under the action of inertia and turbulence. This solution is simple to implement, easy to manage, and has a significant effect on odor drainage in actual operation.

[0025] 4. Water cooling is employed, ensuring high safety and reducing circulating water consumption, thus achieving economic efficiency and energy saving. Considering the potential presence of hydrocarbons in petrochemical odors, this invention utilizes a tubular water-cooled heat exchange system for high-temperature odors, enhancing safety. While circulating water is necessary due to the difference in specific heat capacity between gases and liquids, the volume required is small. Cooling 1500 Nm³ / h of high-temperature odors at 100°C to below 40°C requires approximately 1.8 m³ / h of circulating cooling water at 32°C. The entire heat exchange process is economical and energy-efficient. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the condensate removal device of the present invention;

[0028] In the diagram: 1. Odor collection port; 2. Flame arrestor single-call valve; 3. Flame arrestor; 4. High-temperature odor transport pipeline; 5. Condensation removal device; 6. Regulating valve; 7. Odor heat exchanger; 8. Temperature transmitter; 9. Pressure gauge; 10. Normal temperature odor transport pipeline; 11. Circulating cooling water supply pipeline; 12. Circulating cooling water return pipeline; 13. Level gauge; 14. Separator; 15. Normal temperature odor transport pipeline after condensation removal; 16. Condensate discharge pipeline; 17. Production water supply pipeline; 18. Nitrogen pipeline; 51. Condensation removal baffle; 52. Condensate bag; 53. Condensate transport pipeline; 54. Water trap; 55. Condensate collection well. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 , Figure 2As shown, the high-temperature odor is discharged from the odor collection port 1 of the sewage treatment structure, and is collected into the high-temperature odor conveying pipeline 4 through the flame arrestor single call valve 2 and flame arrester 3. The high-temperature odor conveying pipeline 4 is equipped with an anti-scalding layer and a condensate drainage device 5.

[0031] After initial condensation, the high-temperature odorous gas enters the odorous gas heat exchanger 7. The heat exchanger is a shell-and-tube type with water cooling. The circulating cooling water enters the odorous gas heat exchanger 7 through the circulating cooling water pipe 11 to exchange heat with the high-temperature odorous gas. The circulating cooling return water after heat exchange is transported to the system network through the circulating cooling return water pipe 12.

[0032] After heat exchange, the high-temperature odor gas flows into the separatory tank 14 through the ambient temperature odor gas conveying pipeline 10. A pressure gauge 9 is installed in the pipeline before the tank to monitor the pipeline pressure. After the ambient temperature odor gas enters the separatory tank 14, gas-liquid separation is carried out in the separatory tank 14. The odor gas after secondary condensation is discharged downstream through the ambient temperature odor gas conveying pipeline 15 to mix with other ambient temperature odor gases or to be transported to the downstream odor treatment system.

[0033] The separator is equipped with a level gauge 13 to monitor the liquid level changes in the separator 14. When the liquid level reaches a high level, the level gauge can transmit an alarm remotely. A drain port is provided at the bottom of the tank, from which the condensate is discharged and flows through the condensate discharge pipe 16 to the condensate collection system. A nitrogen port and a production water port are provided at the top of the tank, which are connected to the production water pipe 17 and the nitrogen pipe 18, respectively.

[0034] Nitrogen gas is introduced to further seal the system and maintain a slightly positive pressure within the separatory tank. When the liquid level fluctuates, nitrogen can be added to stabilize the pressure, acting as a gas-phase buffer to balance the system pressure. Additionally, the static pressure of nitrogen allows accumulated condensate at the bottom of the tank to be pumped to the downstream condensate collection system. During maintenance shutdowns, nitrogen purging can replace the gas inside the tank, creating conditions for operation. Introducing production water washes away and dissolves oil mist and other contaminants carried in the odorous gas, improving the separation and purification effect. Simultaneously, it creates a water seal, effectively preventing gas leakage from the condensate pipeline and maintaining the liquid level within the controlled range.

[0035] A regulating valve 6 is installed at the inlet of the odor gas heat exchanger from the high-temperature odor gas conveying pipeline 4. A temperature transmitter 8 is installed at the outlet of the odor gas heat exchanger from the normal-temperature odor gas conveying pipeline 10. The temperature transmitter 8 is interlocked with the regulating valve 6. The temperature of the outlet pipeline is controlled by adjusting the circulating cooling water volume to ensure that the high-temperature odor gas is cooled to below 40°C.

[0036] The condensate drainage device 5 includes a condensate drainage baffle 51, a condensate bag 52, a condensate conveying pipe 53, a water trap 54, and a condensate collection well 55;

[0037] A condensate drain baffle 51 is installed in the high-temperature odor gas conveying pipeline 4. When the high-temperature odor gas flows to the condensate drain baffle 51 in the pipeline, it undergoes inertial collision. As the airflow passes through several turns between the baffles, the droplets contained in the high-temperature odor gas will collide with the baffles due to their large inertia and be adsorbed. The droplets adsorbed at the baffles gradually converge to form a water film. The water film flows downward under the action of gravity until it flows into the condensate bag 52. At the same time, when the airflow passes between the condensate drain baffle 51 and the inner wall of the high-temperature odor gas conveying pipeline 4, the flow area is reduced, resulting in an increase in flow velocity and enhanced turbulence. Small droplets are more likely to aggregate into large droplets, thereby improving the gas-liquid separation rate.

[0038] When the liquid level in the condensate bag 52 rises to a certain height, it can be discharged by gravity through the condensate conveying pipe 53 into the condensate collection well 55. A water trap 54 is installed before entering the condensate collection well 55, which can serve as a water seal.

Claims

1. A high-temperature odor pretreatment system, characterized in that: It includes an odor collection system, a high-temperature odor delivery pipeline, an odor heat exchanger, a normal-temperature odor delivery pipeline, and a liquid separator, all connected in sequence; the odor collection system includes an odor collection port, a flame arrestor single-call valve, and a flame arrestor, all connected in sequence.

2. The high-temperature odor pretreatment system according to claim 1, characterized in that: It also includes a condensate drainage device, which includes a condensate drainage baffle, a condensate bag, a condensate conveying pipeline, and a condensate collection well. The condensate drainage baffle is installed inside the high-temperature odor conveying pipeline, the condensate bag is installed at the bottom of the high-temperature odor conveying pipeline, and the condensate conveying pipeline is connected to the condensate bag to deliver the condensate to the condensate collection well.

3. The high-temperature odor pretreatment system according to claim 2, characterized in that: A water trap is installed on the condensate conveying pipeline.

4. The high-temperature odor pretreatment system according to claim 2, characterized in that: The odor heat exchanger adopts a tubular water-cooled heat exchange type.

5. The high-temperature odor pretreatment system according to claim 2, characterized in that: A regulating valve is installed on the high-temperature odor transmission pipeline, and a temperature transmitter is installed on the normal-temperature odor transmission pipeline. The regulating valve and the temperature transmitter are interlocked.

6. The high-temperature odor pretreatment system according to claim 2, characterized in that: A pressure gauge is installed on the ambient temperature odor delivery pipeline, and a level gauge is installed on the liquid separator.

7. The high-temperature odor pretreatment system according to claim 2, characterized in that: The high-temperature odor delivery pipeline is equipped with a scalding-proof layer.

8. The high-temperature odor pretreatment system according to claim 2, characterized in that: The separator is sealed with nitrogen gas to maintain a slightly positive pressure inside.

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