An improved wet oxidation treatment device

Abstract

This invention belongs to the field of wastewater treatment technology, and particularly relates to an improved wet oxidation treatment device. The invention provides an improved wet oxidation treatment device in which a feed pump and an air compressor are connected to a heat exchanger, and an oxidation tower, heater, gas-liquid separator, turbine expander, steam turbine generator, and exhaust gas treatment device are arranged. This allows for: 1. The heater directly heats the wastewater in the oxidation tower, ensuring thorough oxidation and preventing coking, thus maximizing the continuous operation cycle of the device; 2. The high-temperature steam separated by the gas-liquid separator is converted into electrical energy by the turbine expander and steam turbine generator to power the heater. High-temperature hot pressurized water enters the shell side of the preheater, simultaneously cooling and heating the wastewater in the tube side, resulting in thorough resource utilization and energy conservation; 3. The exhaust gas treatment device purifies the waste gas, increasing the applicability of the device; 4. The heat exchanger ensures that the hot pressurized water does not come into contact with the wastewater during heating, saving treatment costs and streamlining the process, resulting in high wastewater treatment efficiency.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and particularly relates to an improved wet oxidation treatment device. Background Technology

[0002] With the rapid development of society and economy and the rapid development of industry, the discharge of industrial wastewater has attracted increasing attention from all sectors of society. In particular, the production wastewater from industries such as chemical, electroplating, and pharmaceutical has a great hazard to the environment, while wet oxidation technology has solved this problem well.

[0003] Wet oxidation technology, as a novel method for treating organic wastewater, refers to the use of gaseous oxygen (usually air) as an oxidant under high temperature (120~320℃) and high pressure (0.5~20MPa) conditions to oxidize organic matter in water into smaller organic or inorganic molecules. Wet oxidation has wide applications in environmental fields such as industrial wastewater treatment, sludge disposal, and the recovery of useful inorganic salts. The treatment process involves: the wastewater to be treated is pressurized by a high-pressure pump and heated to the required reaction temperature in a heat exchanger before entering the reactor; simultaneously, air or pure oxygen is compressed into the reactor. Inside the reactor, oxidizable pollutants in the wastewater are oxidized by oxygen. After the reaction products are discharged from the reactor, they are cooled using a cooling device and discharged only after meeting the required standards. However, the heaters are often shell-and-tube heaters, and the industrial wastewater often fails to reach the reaction temperature after heating, leading to incomplete reactions, coking, scaling, and heater blockage, affecting operation and requiring shutdown for cleaning.

[0004] Chinese invention patent publication number CN108675434A, published on October 19, 2018, discloses a circulating wet oxidation system. The system includes a heater for heating wastewater, an oxidation tower for oxidizing the heated wastewater to obtain oxidized water, an air compressor unit for supplying air to the oxidation tower, a heat exchanger for exchanging heat between the oxidized water and the wastewater carried into the heater, an intermediate storage tank for diluting the wastewater to be introduced into the heater with the oxidized water, and a circulation unit for transporting the oxidized water to the intermediate storage tank.

[0005] The general structural principle of the circulating wet oxidation system in this invention patent is as follows: The raw water storage tank buffers sufficient wastewater. The wastewater is heated by a heater, and at the same time, an air compressor unit pressurizes air into the oxidation tower, causing the wastewater to react with oxygen in the air under high temperature and high pressure conditions. When the organic or inorganic substances in the wastewater are oxidized and degraded, oxidized water is generated. The circulation unit includes an oxidation storage tank for temporarily storing oxidized water, a pump for discharging the oxidized water from the oxidation storage tank, and a return pipe for returning part of the oxidized water discharged by the pump to an intermediate storage tank. The circulation unit returns part of the oxidized water treated by the oxidation tower to the intermediate storage tank. The intermediate storage tank can dilute the original wastewater flowing out of the raw water storage tank. The diluted wastewater is then heated and enters the oxidation tower for oxidation and degradation, avoiding high temperature and high pressure and the generation of salt crystals.

[0006] However, in actual use, this circulating wet oxidation system still has at least the following three shortcomings, which are the technical problems that this invention aims to solve.

[0007] 1. The oxidation tower in this circulating wet oxidation system does not have a heating device. The raw water is heated before entering the oxidation tower, but it is usually below the reaction temperature. The reaction is incomplete, which can easily cause problems such as coking and scaling, repeated oxidation reactions, or non-compliant discharge.

[0008] 2. In this circulating wet oxidation system, the high-temperature and high-pressure vapor and liquid resources after the oxidation tower reaction are not effectively utilized, which increases the difficulty and cost of treatment and wastes resources.

[0009] 3. This circulating wet oxidation system does not purify the waste gas generated after the oxidation reaction, which affects the ecological environment and limits the nature of the wastewater that needs to be treated, resulting in poor applicability.

[0010] 4. Some of the oxidized water treated by the oxidation tower is recycled back to the intermediate storage tank. The oxidized water after the reaction is mixed with the raw water to dilute the raw water, thereby improving the oxidation effect. This leads to an increase in the workload of the circulating wet oxidation system, a decrease in working efficiency, and may even affect the service life of the equipment.

[0011] Therefore, in summary, there is an urgent need for a new type of wet oxidation treatment device that can achieve sufficient heating, thorough resource utilization, purification of waste gas, and high wastewater treatment efficiency, in order to overcome the barriers of existing technologies. Summary of the Invention

[0012] This invention provides an improved wet oxidation treatment device. The feed pump and air compressor are connected to a heat exchanger, and the device includes an oxidation tower, heater, gas-liquid separator, turbine expander, steam turbine generator, and exhaust gas treatment unit. This design ensures: 1. The heater directly heats the wastewater in the oxidation tower, resulting in thorough oxidation and minimizing coking, thus maximizing the continuous operation cycle of the device; 2. The high-temperature steam separated by the gas-liquid separator is converted into electrical energy by the turbine expander and steam turbine generator to power the heater. High-temperature hot pressurized water enters the shell side of the preheater, simultaneously cooling and heating the wastewater in the tube side, resulting in thorough resource utilization and energy conservation; 3. The exhaust gas treatment unit purifies the waste gas, increasing the device's applicability; 4. The heat exchanger prevents the hot pressurized water from contacting the wastewater during heating, saving treatment costs and streamlining the process, resulting in high wastewater treatment efficiency.

[0013] The technical solution adopted by the present invention to solve the above problems is: an improved wet oxidation treatment device, the structure of which includes a feed pump, an air compressor, a heat exchanger connected to the feed pump and the air compressor in the tube side, an oxidation tower connected to the heat exchanger tube side and oxidizing wastewater to obtain an oxidizing liquid, a heater installed on the oxidation tower, a gas-liquid separator connected to the oxidation tower and separating the oxidizing liquid into steam and hot pressurized water and used to transfer the hot pressurized water to the shell side of the heat exchanger, a turbine expander connected to the gas-liquid separator and converting the thermal energy of the steam into mechanical energy, a steam turbine generator connected to the turbine expander and storing electricity for the heater, a tail flash tank connected to the heat exchanger shell side and separating cooling water into gas and liquid and discharging clean water, and a tail gas treatment device connected to the tail flash tank and used to purify the waste gas.

[0014] A further preferred technical solution is that the heater includes an external power source connected in parallel with the steam turbine generator.

[0015] A further preferred technical solution is that the gas-liquid separation device includes a steam drum.

[0016] A further preferred technical solution is that the gas-liquid separation device also includes a front-end flash tank.

[0017] A further preferred technical solution is that the condensate in the turbine expander is returned to the steam drum.

[0018] A further preferred technical solution is that the steam in the front flash tank is cooled by the turbine expander and then purified by the exhaust gas treatment device.

[0019] A further preferred technical solution is that the heater further includes a heat-conducting U-shaped tube disposed in the oxidation tower, a heat-conducting oil furnace for carrying the hot oil in the heat-conducting U-shaped tube, and a heating rod disposed in the heat-conducting oil furnace for heating the hot oil.

[0020] A further preferred technical solution is that the heater further includes a steam heater disposed within the oxidation tower.

[0021] A further preferred technical solution is that the oxidation tower is equipped with an automatic temperature and pressure detection element.

[0022] A further preferred technical solution is that an agitator is installed inside the oxidation tower. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] Figure 2 This is a schematic diagram showing the location of the steam drum in this invention.

[0025] Figure 3 This is a schematic diagram showing the location of the front flash tank in this invention.

[0026] Figure 4 This is a schematic diagram showing the position of the heat-conducting U-shaped tube in this invention.

[0027] Figure 5 This is a schematic diagram showing the location of the steam heater in this invention.

[0028] The meanings of the markings in the diagram are as follows:

[0029] Solid lines represent liquid transport pipelines, double-dotted lines represent gas or water vapor transport pipelines, and broken lines represent circuit lines.

[0030] Feed pump 11, air compressor 12;

[0031] 1. Heat exchanger; 2. Oxidation tower; 3. Heater; 4. Gas-liquid separation device; 5. Turbine expander; 6. Steam turbine generator; 7. Tail flash tank; 8. Tail gas treatment device; 9. Automatic temperature and pressure detection element; 10. Agitator.

[0032] External power supply 301, heat-conducting U-tube 302, heat-conducting oil furnace 303, heating rod 304, steam heater 305, steam drum 401, front flash tank 402. Detailed Implementation

[0033] The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

[0034] As attached Figure 1-5As shown, an improved wet oxidation treatment device includes a feed pump 11, an air compressor 12, a heat exchanger 1 with the feed pump 11 and the air compressor 12 connected in tubes, an oxidation tower 2 connected in tubes of the heat exchanger 1 to oxidize wastewater to obtain an oxidized liquid, a heater 3 installed on the oxidation tower 2, a gas-liquid separator 4 connected to the oxidation tower 2 to separate the oxidized liquid into steam and hot pressurized water and to transfer the hot pressurized water to the shell side of the heat exchanger 1, a turbine expander 5 connected to the gas-liquid separator 4 to convert the thermal energy of the steam into mechanical energy, a steam turbine generator 6 connected to the turbine expander 5 to store electricity for the heater 3, a tail flash tank 7 connected to the shell side of the heat exchanger 1 to separate cooling water into gas and liquid and discharge clean water, and a tail gas treatment device 8 connected to the tail flash tank 7 to purify the waste gas.

[0035] In this embodiment, the improved wet oxidation treatment device treats wastewater by having wastewater enter the tube side of the heat exchanger 1 through the feed pump 11, while the air compressor 12 pressurizes pure oxygen or air into it. The wastewater is then transported to the oxidation tower 2 through a liquid transmission pipeline. The heater 3 in the oxidation tower 2 has an independent power supply system. The heater 3 heats the wastewater in the oxidation tower 2 to reach the temperature required for the oxidation reaction, thus better oxidizing and decomposing the oxidizable pollutants in the wastewater. After oxidation, a high-temperature oxidized liquid is obtained. The oxidized liquid enters the gas-liquid separation device 4 for gas-liquid separation, separating it into high-temperature steam and hot pressurized water. The high-temperature steam is transported to the turbine expander 5 through a gas or steam transmission pipeline. The turbine expander 5 converts the thermal energy of the steam into mechanical energy, which is then converted into electrical energy by a steam turbine generator. The recovered electrical energy is used to replenish the heater 3 through electrical circuits. By recovering electrical energy, resource consumption is saved, and energy conservation and environmental protection are achieved. The separated hot pressurized water is at a high temperature and is transported to the shell side of the heat exchanger 1 through a liquid transmission pipeline. This allows the high-temperature hot pressurized water to assist in heating the wastewater that needs to be heated in the tube side of the heat exchanger 1. The hot pressurized water is heated while cooling the wastewater. The cooled hot pressurized water becomes cooling water and is discharged from the shell side of the heat exchanger 1. Since the wastewater will generate waste gas during the oxidation process, the waste gas in the liquid needs to be separated. The cooling water is transported to the tail flash tank 7 through a liquid transmission pipeline for gas-liquid separation. The separated liquid is treated by evaporation or biochemical post-treatment processes to meet the emission standards. The separated waste gas is polluting and needs to be transported to the tail gas treatment device 8 through a gas or water vapor transmission pipeline for purification before being discharged.

[0036] Furthermore, the purpose of the heat exchanger 1 is to facilitate the exchange of thermal energy between the high-temperature hot pressurized water and the wastewater, fully utilizing the thermal energy of the hot pressurized water after the reaction. It simultaneously cools the wastewater and heats it, reducing or eliminating the need for a cooling device. Therefore, the structure of the heat exchanger 1 is not unique, and the connection methods between the tube side, shell side, and the hot pressurized water and wastewater are not unique. The heat exchanger 1 prevents direct contact between the wastewater and the hot pressurized water, while simultaneously using the high-temperature hot pressurized water to provide auxiliary heating for the low-temperature wastewater. This results in a simple structure, thorough resource utilization, and improved treatment efficiency of the improved wet oxidation treatment device.

[0037] Furthermore, the heater 3 is directly installed inside the oxidation tower 2, reducing heat loss after heating the wastewater. The oxidation conditions inside the oxidation tower 2 are better, and the oxidation reaction is more complete. At the same time, it reduces the possibility of coking and scaling of the wastewater, maximizing the continuous operation cycle of the device. The gas-liquid separation device 4 is used to separate the gas and liquid for use, and the superheated steam is converted into electrical energy through the turbine expander 5 and the steam turbine generator 6 to supplement the heater 3 with electrical energy. This efficient use of the energy produced during operation makes the energy-saving and environmental protection capabilities of the improved wet oxidation treatment device reach a high level, maximizing the continuous operation cycle of the improved wet oxidation treatment device.

[0038] Finally, the exhaust gas treatment device 8 purifies the waste gas separated after the reaction, which greatly expands the application scenarios of the improved wet oxidation treatment device. It can not only handle the situation where there is no waste gas after the reaction, but also handle the situation where there is waste gas after the reaction. The wastewater and waste gas treated by the improved wet oxidation treatment device can meet the emission standards and will not affect the surrounding environment.

[0039] The heater 3 includes an external power supply 301 connected in parallel with the steam turbine generator 6.

[0040] In this embodiment, the external power supply 301 is connected in parallel with the circuit of the turbine generator 6, mainly to supplement the power supply of the heater 3. This prevents situations where the external power supply 301 has a high power demand and the turbine generator 6 has insufficient power supply. Moreover, when the improved wet oxidation treatment device is started and a temporary power outage occurs, not only can the turbine generator 6 store electricity for the heater 3, but the external power supply 301 can also store electricity, without affecting the normal operation of the improved wet oxidation treatment device.

[0041] The gas-liquid separation device 4 includes a steam drum 401.

[0042] In this embodiment, the gas-liquid separation device 4 can be the steam drum 401. After passing through the steam drum 401, the oxidizing liquid is obtained as superheated clean water vapor and high-temperature hot pressurized water. The superheated steam enters the turbine expander 5 through a gas or water vapor transmission pipeline, converting the steam heat energy into mechanical energy. After the water vapor is cooled, it becomes condensate that can be used as soft water. The hot pressurized water separated by the steam drum 401 is connected to the shell side of the heat exchanger 1 through a liquid transmission pipeline. The high-temperature hot pressurized water provides auxiliary heating to the wastewater in the tube side of the heat exchanger 1, making the best use of the gaseous and liquid heat of the oxidizing liquid obtained from the reaction.

[0043] The gas-liquid separation device 4 also includes a front-end flash tank 402.

[0044] In this embodiment, the gas-liquid separation device 4 can also be the front flash tank 402. The front flash tank 402 performs gas-liquid separation on the oxidizing liquid. During separation, the steam in the front flash tank 402 comes into direct contact with the hot pressurized water to form high-temperature and high-pressure hot pressurized water and superheated steam. The separated hot pressurized water is sent to the shell side of the heat exchanger 1. The steam enters the turbine expander 5 and is converted into mechanical energy. The steam separated by the gas-liquid separation device 4 may be contaminated and needs to be purified by the exhaust gas treatment device 8.

[0045] The condensate in the turboexpander 5 flows back to the steam drum 401.

[0046] In this embodiment, since the steam drum 401 separates clean high-temperature water vapor, which is then transported to the turboexpander 5, the heat is released and it is cooled into clean condensate, which can be directly used as the soft water required by the steam drum 401, thus recycling resources.

[0047] The steam in the front flash tank 402 is cooled by the turbine expander 5 and then purified by the exhaust gas treatment device 8.

[0048] In this embodiment, since the vapor separated by the front flash tank 402 is a gas that has undergone an oxidation reaction and may cause pollution, the exhaust gas after passing through the turbine expander 5 cannot be directly discharged and needs to be purified by the exhaust gas treatment device 8 before being discharged.

[0049] The heater 3 also includes a heat-conducting U-shaped tube 302 disposed in the oxidation tower 2, a heat-conducting oil furnace 303 for carrying the hot oil in the heat-conducting U-shaped tube 302, and a heating rod 304 disposed in the heat-conducting oil furnace 303 for heating the hot oil.

[0050] In this embodiment, the heat-conducting U-shaped tube 302 is a U-shaped tube filled with hot oil. The heat from the hot oil supplements the heating of the wastewater in the oxidation tower 2. The cooled hot oil flows back to the heat-conducting oil furnace 303, where the heating rod 304 heats the oil. The heated oil then flows back into the heat-conducting U-shaped tube 302, thus completing the heating process. The heating rod 304 can be an independent power supply system, or it can be powered by the steam turbine generator 6.

[0051] The heater 3 also includes a steam heater 305 disposed within the oxidation tower 2.

[0052] In this embodiment, the steam heater 305 is installed inside the oxidation tower 2 and has an independent heating system to supplement the heating of the wastewater inside the oxidation tower 2.

[0053] The oxidation tower 2 is equipped with an automatic temperature and pressure detection element 9.

[0054] In this embodiment, the automatic temperature and pressure detection element 9 is an existing device, such as the automatic temperature and pressure detection device of Shandong Xinwei Internet of Things Technology Co., Ltd. The automatic temperature and pressure detection element 9 can be programmed by computer to provide feedback on the electrical energy that needs to be replenished, and the energy can be replenished by an external power supply 301.

[0055] The oxidation tower 2 is equipped with a stirrer 10.

[0056] In this embodiment, the stirrer 10 is used to make the wastewater in the oxidation tower 2 heated more evenly and the oxidation reaction more complete.

[0057] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various modifications can be made without departing from the spirit of the present invention. These are non-inventive modifications and are protected by patent law as long as they fall within the scope of the claims of the present invention.

Claims

1. An improved wet oxidation treatment apparatus, comprising a feed pump (11) and an air compressor (12), characterized in that, It also includes a heat exchanger (1) with the feed pump (11) and air compressor (12) connected in the tube side; an oxidation tower (2) connected in the tube side of the heat exchanger (1) and oxidizing wastewater to obtain an oxidized liquid; a heater (3) installed on the oxidation tower (2); a gas-liquid separator (4) connected to the oxidation tower (2) and separating the oxidized liquid into steam and hot pressurized water and used to transfer the hot pressurized water to the shell side of the heat exchanger (1); a turbine expander (5) connected to the gas-liquid separator (4) and converting the heat energy of the steam into mechanical energy; a steam turbine generator (6) connected to the turbine expander (5) and storing electricity for the heater (3); a tail flash tank (7) connected to the shell side of the heat exchanger (1) and separating cooling water into gas and liquid and discharging clean water; and a tail gas treatment device (8) connected to the tail flash tank (7) and used to purify waste gas.

2. The improved wet oxidation treatment apparatus according to claim 1, characterized in that: The heater (3) includes an external power source (301) connected in parallel with the steam turbine generator (6).

3. The improved wet oxidation treatment apparatus according to claim 1, characterized in that: The gas-liquid separation device (4) includes a steam drum (401).

4. An improved wet oxidation treatment apparatus according to claim 1, characterized in that: The gas-liquid separation device (4) also includes a front-end flash tank (402).

5. An improved wet oxidation treatment apparatus according to claim 3, characterized in that: The condensate in the turboexpander (5) flows back to the steam drum (401).

6. An improved wet oxidation treatment apparatus according to claim 4, characterized in that: The steam in the front flash tank (402) is cooled by the turbine expander (5) and then purified by the exhaust gas treatment device (8).

7. An improved wet oxidation treatment apparatus according to claim 1, characterized in that: The heater (3) also includes a heat-conducting U-tube (302) disposed in the oxidation tower (2), a heat-conducting oil furnace (303) for carrying the hot oil in the heat-conducting U-tube (302), and a heating rod (304) disposed in the heat-conducting oil furnace (303) for heating the hot oil.

8. An improved wet oxidation treatment apparatus according to claim 1, characterized in that: The heater (3) also includes a steam heater (305) disposed within the oxidation tower (2).

9. An improved wet oxidation treatment apparatus according to claim 1, characterized in that: The oxidation tower (2) is equipped with an automatic temperature and pressure detection element (9).

10. An improved wet oxidation treatment apparatus according to claim 1, characterized in that: The oxidation tower (2) is equipped with a stirrer (10).

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