Wet oxidation treatment system

Abstract

The utility model belongs to the technical field of organic wastewater treatment equipment, and particularly relates to a wet oxidation treatment system. The utility model provides a wet oxidation treatment system which is characterized in that raw water with high COD (Chemical Oxygen Demand) in the first feed pump enters the oxidation tower directly or after being properly preheated by the preheater through a mode of arranging a first feed pump, a second feed pump, a preheater, a heat exchanger and a steam generator among the oxidation tower, an air buffer tank and an oxidation separation tank; raw water with low COD in the second feeding pump passes through the heat exchanger and then enters the oxidation tower, part of oxidation liquid of the oxidation reaction exchanges heat with the raw water through the shell pass of the heat exchanger, is cooled and then is discharged, the other part of oxidation liquid of the oxidation reaction is cooled through the steam generator and then is discharged, and raw water with different properties can be heated in a classified mode. Different cooling modes of the oxidation liquid are selected according to the reaction heat value difference of the raw water, so that the treatment mode is more scientific and reasonable, the load and cost of unified treatment are greatly reduced, the service life of equipment is prolonged, and the oxidation treatment efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of organic wastewater treatment equipment, in particular to a wet oxidation treatment system. Background Art

[0002] Wastewater treatment technologies include biochemical treatment, advanced oxidation and wet oxidation. Wet oxidation WAO refers to a chemical process that uses air or ozone, pure oxygen, hydrogen peroxide, etc. as oxidants to oxidize and decompose pollutants into inorganic or small molecular organic matter under high temperature 150-320°C and high pressure 0.5-20MPa. Wet oxidation has a short reaction time and less secondary pollution, so it has received widespread attention and has good application prospects.

[0003] Wet oxidation is suitable for treating various types of wastewater and is an important part of wastewater treatment technology. It can make up for many deficiencies of biochemical treatment technology and advanced oxidation technology. Conventional wet oxidation process requires the raw materials to be prepared into a fluid state with a solid content of less than 10%, and then transported to the heat exchanger for heat exchange through a high-pressure pump, and then enter the WAO reactor.

[0004] The Chinese invention patent with patent publication number CN117466422A and publication date 2024.01.30 discloses a multi-stage preheating wet oxidation system and process. The structure includes a preheating tank connected to a buffer tank, a heat exchanger and a WAO reactor in sequence. The raw materials are heated twice and thrice, and the steam comes from the WAO reactor.

[0005] The general structural principle of the multi-stage preheating wet oxidation system and process in this invention patent is as follows: the raw material is heated once by the steam discharged from the WAO reactor, the raw material heated once exchanges heat with the discharge of the WAO reactor and is heated twice, and the second-heated raw material is sent to the WAO reactor and heated three times; this method is to preheat the raw material, the initial raw material is semi-solid, but it is converted into a completely fluid state during the step-by-step preheating process, making the raw material transportation, heat exchange and other process operations feasible. Due to the increase in raw material concentration; and the setting of a multi-stage preheating process, the temperature rise during the final heating is reduced, and the operating energy consumption is significantly lower than the conventional wet oxidation process.

[0006] However, the wet oxidation system and process still have at least the following two deficiencies in actual use, in other words, these are the technical problems to be solved by the present utility model.

[0007] 1. The wet oxidation system and process treat all raw water in a unified manner and cannot classify raw water of different properties, resulting in heavy treatment burden and high treatment cost.

[0008] 2. Due to the different properties of raw water, when there is a lot of wastewater with high calorific value, the heat exchanger does not need to use all the oxidizing liquid to preheat the raw water. On the contrary, the oxidizing liquid requires more circulating water to cool down, increasing the treatment cost.

[0009] Therefore, in summary, there is an urgent need for a new wet oxidation treatment system that can classify raw water with different calorific values ​​and divert the oxidizing liquid for energy recovery. Utility Model Content

[0010] The utility model provides a wet oxidation treatment system, which can arrange a first feed pump, a second feed pump, a preheater, a heat exchanger, and a steam generator between an oxidation tower, an air buffer tank, and an oxidation separation tank, so that: raw water with high COD in the first feed pump enters the oxidation tower directly or after being properly preheated by the preheater, raw water with low COD in the second feed pump enters the oxidation tower after passing through the heat exchanger, a part of the oxidized liquid of the oxidation reaction is discharged after being cooled by heat exchange with the raw water in the shell side of the heat exchanger, and another part of the oxidized liquid of the oxidation reaction is discharged after being cooled by the steam generator, raw water of different properties can be heated according to classification, and different cooling methods for the oxidized liquid can be selected according to the difference in the calorific value of the raw water reaction, the treatment method is more scientific and reasonable, which greatly reduces the burden and cost of unified treatment, prolongs the life of the equipment, and improves the oxidation treatment efficiency.

[0011] The technical solution adopted by the utility model to solve the above-mentioned problem is: a wet oxidation treatment system, the structure of which includes an oxidation tower, an air buffer tank and an oxidation separation tank, and also includes a first feed pump and a second feed pump, two raw water pipelines are connected between the first feed pump and the oxidation tower, one of the raw water pipelines is provided with a preheater for heating the raw water; a heat exchanger connected to the second feed pump and the oxidation tower and used for inputting the oxidized liquid after heat exchange into the oxidation separation tank, and a steam generator connected to the oxidation tower and used for inputting the oxidized liquid after cooling into the oxidation separation tank.

[0012] A further preferred technical solution is that the steam generator is connected to a steam drum, and a water circulation pump connected to the steam drum and used to provide water to the steam generator.

[0013] A further preferred technical solution is that two connecting oxidation liquid pipelines are arranged between the oxidation separation tank and the preheater.

[0014] A further preferred technical solution is that an oxidation cooler is connected to the oxidation liquid pipeline between the oxidation separation tank and the preheater.

[0015] A further preferred technical solution is that the shell side of the heat exchanger is connected to the preheater, and the shell side of the preheater is connected to the oxidation separation tank.

[0016] A further preferred technical solution is that at least two heat exchangers are connected in series.

[0017] A further preferred technical solution is that a heater for heating raw water is provided in the oxidation tower.

[0018] A further preferred technical solution is that the oxidation separation tank is connected to an exhaust gas purification device for purifying exhaust gas.

[0019] A further preferred technical solution is that a catalyst feed pump is connected to the oxidation tower.

[0020] A further preferred technical solution is that the air buffer tank is connected to the preheater tube side, the heat exchanger tube side and the oxidation tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the utility model.

[0022] Figure 2 This is the position connection diagram of the utility model.

[0023] Figure 3 This is the position connection diagram of the oxidation cooler in the utility model.

[0024] In the figure, the meanings of the symbols are as follows:

[0025] The solid line is the liquid transmission pipeline after the oxidation reaction, the dotted line is the liquid transmission pipeline of the raw water, the broken line is the gas transmission pipeline, and the dotted line is the catalyst transmission pipeline;

[0026] Oxidation tower 11, air buffer tank 12, oxidation separation tank 13, catalyst feed pump 14;

[0027] A first feed pump 1, a second feed pump 2, a preheater 3, a heat exchanger 4, a steam generator 5, a steam drum 6, a water circulation pump 7, an oxidation cooler 8, a heater 9, and an exhaust gas purification device 10. DETAILED DESCRIPTION

[0028] The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

[0029] As attached Figure 1-3As shown, a wet oxidation treatment system comprises an oxidation tower 11, an air buffer tank 12 and an oxidation separation tank 13, and also comprises a first feed pump 1 and a second feed pump 2, wherein two raw water pipelines are connected between the first feed pump 1 and the oxidation tower 11, and one of the raw water pipelines is provided with a preheater 3 for heating raw water; a heat exchanger 4 connected with the second feed pump 2 and the oxidation tower 11 and used for inputting the oxidized liquid after heat exchange into the oxidation separation tank 13; and a steam generator 5 connected with the oxidation tower 11 and used for inputting the oxidized liquid after cooling into the oxidation separation tank 13.

[0030] In this embodiment, the oxidation tower 11 is used to perform an oxidation reaction on the raw water to obtain an oxidized liquid. The air compressor presses oxygen / air into the air buffer tank 12. The air buffer tank 12 inputs oxygen or air to the oxidation tower. The oxidation separation tank 13 is used to separate the gas and liquid of the oxidized liquid and discharge it.

[0031] In addition, in the wastewater treatment project, due to the different characteristics of raw water, the COD of raw water is different, and the speed of heating and coking is also different. Raw water with high COD can directly enter the oxidation tower 11 through the first feed pump 1, or it can enter the oxidation tower 11 after being properly preheated by the preheater 3. The preheater 3 can be heated by electric heating, heat transfer oil or steam, and the preheating temperature is within 200°C; while for raw water with low COD, after passing through the second feed pump 2, it passes through the heat exchanger 4 and then enters the oxidation tower 11. The preheating temperature of the heat exchanger 4 is easy to be above 200°C. According to the different calorific values ​​of raw water, the preheating of raw water is classified and processed, and the energy utilization is maximized while increasing the preheating and oxidation reaction efficiency of raw water. If the same treatment process is used, it will cause a waste of investment, especially for projects with a large proportion of wastewater prone to coking, which will aggravate the blockage cycle of heaters and the like, causing production interruption.

[0032] Finally. Due to the difference in calorific value of the raw water oxidation reaction, the oxidizing liquid needs to choose different cooling methods. When the calorific value of the raw water is low, the oxidizing liquid does not need too much circulating water to cool it down. The heat exchanger 4 can be connected to heat the raw water while cooling the oxidizing liquid, and the heat energy after the oxidation reaction can be recycled for energy saving and environmental protection; when the calorific value of the raw water is high, the oxidizing liquid needs more circulating water to cool down, and the oxidizing liquid needs to be cooled by the steam generator 5. The steam generator 5 can also be replaced by a cooler of other cold media, such as circulating water, thermal oil, etc. The cooled oxidizing liquid is separated and discharged by the oxidation separation tank 13, and the wet oxidation system of the entire raw water is completed.

[0033] The steam generator 5 is connected to a steam drum 6 and a water circulation pump 7 connected to the steam drum 6 and used for supplying water to the steam generator 5 .

[0034] In this embodiment, the steam generator 5 can also be replaced by a cooler of other cold media, such as heat transfer oil, circulating water, etc. Since the calorific value of raw water is high, a large amount of circulating water is required to cool the oxidizing liquid. The steam generator 5 is used to take away the waste heat of such oxidizing liquid. In order to ensure the stability of the equipment and the quality of steam, the steam drum 6 is provided to ensure the safe operation of the steam generator 5. The steam drum 6 separates steam and water, and the separated steam is discharged after reaching the quality standard. The separated water enters the water circulation pump 7 and is connected to the steam generator 5.

[0035] Two connecting oxidation liquid pipelines are arranged between the oxidation separation tank 13 and the preheater 3 .

[0036] In this embodiment, two oxidizing liquid connecting pipelines are provided between the oxidation separation tank 13 and the preheater 3 for the purpose of adjusting the outlet water temperature of the oxidizing liquid.

[0037] The oxidation liquid pipeline between the oxidation separation tank 13 and the preheater 3 is connected with an oxidation cooler 8 .

[0038] In this embodiment, the function of the oxidation cooler 8 is to cool the oxidizing liquid again to ensure that the discharge temperature of the oxidizing liquid is appropriate. The oxidation cooler 8 can be respectively set on the oxidation liquid pipeline between the oxidation separation tank 13 and the preheater 3, or the oxidation cooler 8 can be set on one of the oxidation liquid pipelines.

[0039] The shell side of the heat exchanger 4 is connected to the preheater 3 , and the shell side of the preheater 3 is connected to the oxidation separation tank 13 .

[0040] In this embodiment, the oxidizing liquid with a lower raw water calorific value can be directly connected to the oxidation separation tank 13 after being cooled by heat exchange in the heat exchanger 4; in addition, the preheater 3 can preheat the raw water in the first feed pump 1 by heat exchange, and the oxidizing liquid can be cooled by heat exchange in the heat exchanger 4 and then connected to the oxidation separation tank 13 after being cooled by heat exchange in the preheater 3, and the heat in the oxidizing liquid can be taken away by the low-temperature raw water in the first feed pump 1 and the second feed pump 2. Similarly, the oxidizing liquid with a higher raw water calorific value can be directly connected to the oxidation separation tank 13 after being cooled by the steam generator 5, or it can be connected to the oxidation separation tank 13 after being cooled by heat exchange in the preheater 3.

[0041] At least two heat exchangers 4 are connected in series.

[0042] In this embodiment, at least two heat exchangers 4 are connected in series, which not only improves the heating effect of the raw water and reduces the heating burden of the heat exchanger 4, but also improves the heat exchange effect between the oxidizing liquid and the raw water when the oxidizing liquid exchanges heat through the heat exchanger 4, and has a higher cooling efficiency.

[0043] The oxidation tower 11 is provided with a heater 9 for heating raw water.

[0044] In this embodiment, the function of the heater 9 is to supplement and heat the raw water entering the oxidation tower 11, thereby ensuring the temperature requirement in the oxidation tower 11 and ensuring the oxidation reaction effect.

[0045] The oxidation separation tank 13 is connected to an exhaust gas purification device 10 for purifying exhaust gas.

[0046] In this embodiment, since waste gas is generated during the oxidation reaction, in order to further protect the environment, the exhaust gas separated by the oxidation separation tank 13 can be purified by the exhaust gas purification device 10.

[0047] The oxidation tower 11 is provided with a catalyst feed pump 14 .

[0048] In this embodiment, the function of the catalyst feed pump 14 is to accelerate the oxidation reaction rate and to supply the catalyst when the reaction rate of the oxidation tower 11 is low or the catalyst is insufficient.

[0049] The air buffer tank 12 is connected to the tube side of the preheater 3 , the tube side of the heat exchanger 4 and the oxidation tower 11 .

[0050] In this embodiment, the air buffer tank 12 can directly supply oxygen or air to the oxidation tower 11, or it can be connected to the raw water pipeline of the preheater 3 and the heat exchanger 4, and oxygen or air can be input while injecting raw water to provide conditions for the oxygen and high-pressure environment required for the oxidation tower reaction.

[0051] The above is a detailed description of the implementation of the utility model in conjunction with the accompanying drawings, but the utility model is not limited to the above implementation. Various modifications can be made within the knowledge of ordinary technicians in the technical field without departing from the purpose of the utility model. These are all non-creative modifications and are protected by patent law as long as they are within the scope of the claims of the utility model.

Claims

1. A wet oxidation treatment system, comprising an oxidation tower (11), an air buffer tank (12) and an oxidation separation tank (13), characterized in that: The invention also comprises a first feed pump (1) and a second feed pump (2), wherein two raw water pipelines are connected between the first feed pump (1) and the oxidation tower (11), one of the raw water pipelines being provided with a preheater (3) for heating raw water; a heat exchanger (4) connected to the second feed pump (2) and the oxidation tower (11) and used for inputting the oxidized liquid after heat exchange into the oxidation separation tank (13); and a steam generator (5) connected to the oxidation tower (11) and used for inputting the oxidized liquid after cooling into the oxidation separation tank (13).

2. A wet oxidation treatment system according to claim 1, characterized in that: The steam generator (5) is connected to a steam drum (6), and a water circulation pump (7) connected to the steam drum (6) and used to supply water to the steam generator (5).

3. A wet oxidation treatment system according to claim 1, characterized in that: Two oxidation liquid connecting pipelines are arranged between the oxidation separation tank (13) and the preheater (3).

4. A wet oxidation treatment system according to claim 3, characterized in that: An oxidation cooler (8) is connected to the oxidation liquid pipeline between the oxidation separation tank (13) and the preheater (3).

5. A wet oxidation treatment system according to claim 1, characterized in that: The shell side of the heat exchanger (4) is connected to the preheater (3), and the shell side of the preheater (3) is connected to the oxidation separation tank (13).

6. A wet oxidation treatment system according to claim 1, characterized in that: At least two heat exchangers (4) are connected in series.

7. A wet oxidation treatment system according to claim 1, characterized in that: A heater (9) for heating raw water is arranged in the oxidation tower (11).

8. A wet oxidation treatment system according to claim 1, characterized in that: The oxidation separation tank (13) is connected to an exhaust gas purification device (10) for purifying exhaust gas.

9. A wet oxidation treatment system according to claim 1, characterized in that: The oxidation tower is connected to a catalyst feed pump (14).

10. A wet oxidation treatment system according to claim 1, characterized in that: The air buffer tank (12) is connected to the tube side of the preheater (3), the tube side of the heat exchanger (4) and the oxidation tower (11).

Images