WO2020155692A1

WO2020155692A1 - Sludge supercritical water oxidation system using heat-conducting oil as heat exchange medium and sludge treatment method

Info

Publication number: WO2020155692A1
Application number: PCT/CN2019/113365
Authority: WO
Inventors: 王树众; 杨健乔; 张熠姝; 徐海涛; 王栋; 张宝权; 李艳辉
Original assignee: 西安交通大学
Priority date: 2019-01-31
Filing date: 2019-10-25
Publication date: 2020-08-06
Also published as: CN109851187A; CN109851187B

Abstract

Disclosed in the present invention are a sludge supercritical water oxidation system using heat-conducting oil as a heat exchange medium and a sludge treatment method. Sludge is introduced into a sludge pyrohydrolysis tank, then conveyed to a heat exchanger by means of a material pump for heating and mixed with oxygen to undergo a supercritical water oxidation reaction in a reactor to release a lot of heat. The high-temperature fluid obtained by the reaction first passes through the heat exchanger, and then passes through a heat-conducting oil heat exchanger to transfer the heat to heat-conducting oil. The heat-conducting oil enters an outer wall coil of the sludge pyrohydrolysis tank to heat the sludge pyrohydrolysis tank, so as to ensure the progress of pyrohydrolysis reaction. By means of the heat-conducting oil heat exchanger using the heat-conducting oil as a heat exchange medium for the heat released by the super-critical water oxidation reaction, the heat from a high-pressure strongly-corrosive heat source is converted to a normal-pressure non-corrosive heat source, and therefore, the safety, economy and reliability of the system are improved comprehensively, the super-critical water oxidation reaction is accomplished, and up-to-standard discharge is achieved.

Description

Sludge supercritical water oxidation system using heat transfer oil as heat exchange medium and sludge treatment method

Technical field

The invention belongs to the technical field of chemical industry and environmental protection, and specifically relates to a sludge supercritical water oxidation system using heat transfer oil as a heat exchange medium and a sludge treatment method.

Background technique

Supercritical water refers to water in a special state whose temperature and pressure both exceed the critical point of water (374℃, 22.1MPa). As the phase state of water enters the supercritical state, the density and ion product constant of the water are significantly reduced, and the viscosity is greatly reduced. The decline leads to increased liquidity. At the same time, supercritical water tends to be a non-polar fluid, which can almost completely dissolve organic matter and gas.

Supercritical water oxidation (supercritical water oxidation) technology takes advantage of the many advantages of supercritical water, and uses supercritical water as a medium for the oxidation reaction of organic matter in high-concentration organic wastewater/sludge with oxygen, and performs rapid, rapid, Efficient removal. At present, supercritical water oxidation technology has been widely used in the fields of military industry, chemical industry, aerospace, ship and environmental protection, and is used to treat high-concentration refractory organic matter such as wastewater and sludge generated in various fields, and convert organic matter into Harmless carbon dioxide, nitrogen, water and other substances. Supercritical water oxidation technology has the following advantages:

1. The reaction speed is extremely fast, and the oxidation reaction can be completed within hundreds of seconds.

2. The reaction efficiency is high. Because of the high temperature and high pressure environment, the COD removal rate of organic matter can generally reach more than 99%.

3. Since the oxidation reaction itself is exothermic, self-heating can be achieved when the concentration of organic matter in the system is sufficient.

Due to the huge advantages of supercritical water oxidation technology, the technology is rapidly being promoted throughout the world, including China. The main treatment objects of the existing supercritical water oxidation devices in my country are municipal sludge and industrial sludge produced by various chemical industry wastewater treatment plants.

However, during the promotion and application of sludge supercritical water oxidation technology, the following defects were discovered:

In order to make the sludge have fluidity and flow in equipment pipelines, it is generally necessary to dilute the sludge feedstock before it enters the supercritical water oxidation system to increase its water content and reduce its viscosity. On the other hand, adding a large amount of clean water to the sludge to be treated increases the amount of sludge to be treated, thereby increasing the operating cost, which is unacceptable for any commercial device. In addition to diluting with water, another method to improve the fluidity of sludge is heating, because the viscosity of sludge decreases with increasing temperature, and the sludge undergoes thermal hydrolysis at about 200°C, which can make Part of the microbial cell bodies in the sludge rupture due to thermal expansion, releasing organic matter and moisture, thereby increasing the fluidity of the sludge. The sludge thermal hydrolysis reaction is irreversible. Once the thermal hydrolysis reaction is completed, there is no need to worry about the transportation of sludge in the system. Therefore, the sludge thermal hydrolysis technology is used as a pretreatment method for sludge supercritical water It is very effective on the oxidation device.

The supercritical water oxidation reaction is an exothermic reaction. The exothermic heat of the reaction still remains after the cold material is preheated, which can be directly applied to the heat source of the sludge thermal hydrolysis device. In fact, some current devices are also designed in this way. By installing coils in the thermal hydrolysis tank, the high temperature and high pressure hot fluid after the reaction and passing through the heat exchanger enters the thermal hydrolysis tank and exchanges with the sludge in the tank. Heat, heat the sludge in the tank to a preset temperature, so as to realize the thermal hydrolysis reaction of the sludge and reduce the viscosity of the sludge.

However, in the actual operation process, there is a very difficult problem that is difficult to solve, that is, the sludge will coke and scale on the inner coil of the thermal hydrolysis tank, which will seriously affect the heat exchange effect. Since the sludge thermal hydrolysis tank needs to reach a high temperature higher than 100℃, a constant pressure device must be installed in the tank to avoid high temperature vaporization of the sludge, which means that the device is airtight during operation and cannot be simply disassembled. To clean up the dirt on the surface of the pipeline, it can only be forced to shut down for cleaning, which seriously affects the safety and stability of system operation.

Summary of the invention

In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a sludge supercritical water oxidation system and a sludge treatment method using heat transfer oil as the heat exchange medium. The system has a reasonable structure and can solve the problem of internal coil heating. The problem of scaling and coking of the sludge on the surface of the inner coil of the sludge thermal hydrolysis tank improves the stability and reliability of the system.

In order to achieve the above objectives, the present invention adopts the following technical solutions to achieve:

The invention discloses a sludge supercritical water oxidation system using heat transfer oil as a heat exchange medium, which includes a sludge thermal hydrolysis tank, a heat exchanger, a reactor and a heat transfer oil heat exchanger;

Among them, the sludge thermal hydrolysis tank is connected to the heat exchanger through a material pump, the tube side outlet end of the heat exchanger is connected to the reactor inlet end, and the reactor outlet end is connected to the shell side inlet end of the heat exchanger. The shell-side outlet of the heat exchanger is connected with the inlet end of the heat transfer oil heat exchanger, and the outlet end of the heat transfer oil heat exchanger is connected with the heating coil set on the outer wall of the sludge thermal hydrolysis tank;

It also includes a back pressure valve and a three-phase separator that are connected to the pipe side outlet of the heat transfer oil heat exchanger in sequence. The pipe side outlet end of the heat transfer oil heat exchanger is connected to the back pressure valve inlet, and the outlet of the back pressure valve is separated from the three phases. The inlet of the three-phase separator is connected with an exhaust port at the top of the three-phase separator, a slag discharge port at the bottom, and a liquid discharge port on the cylinder wall.

Preferably, the sludge thermal hydrolysis tank includes a first sludge thermal hydrolysis tank and a second sludge thermal hydrolysis tank that are connected, and the material pump is arranged at the connection between the second sludge thermal hydrolysis tank and the heat exchanger. On the pipeline.

More preferably, it also includes an electric heater connected to the shell side outlet of the heat transfer oil heat exchanger, and the outlet of the electric heater is connected to the heating coil inlet on the outer wall of the second sludge thermal hydrolysis tank. The outlet of the heating coil on the outer wall of the hydrolysis tank is connected with the inlet of the heating coil on the outer wall of the first sludge thermal hydrolysis tank, and the outlet of the heating coil on the outer wall of the first sludge thermal hydrolysis tank is connected with an oil-gas separator through a pipeline;

The outlet of the oil-air separator is connected with a filter through a pipeline, and the outlet of the filter is connected to the shell side inlet of the heat transfer oil heat exchanger through a pipeline at the outlet end of the circulating pump, the shell side outlet of the heat transfer oil heat exchanger and the electric heater Connected, another pipeline at the outlet end of the circulating pump is connected with an electric heater, and an automatic regulating valve is arranged on the pipeline.

More preferably, it further includes an expansion tank, and the gas outlet at the top of the oil-gas separator is connected to the expansion tank.

More preferably, a branch connected to the expansion tank is provided on the pipeline between the shell side outlet of the heat transfer oil heat exchanger and the electric heater inlet.

Preferably, a stirring device is provided in the sludge thermal hydrolysis tank.

The invention also discloses a sludge treatment method based on the above-mentioned sludge supercritical water oxidation system using heat transfer oil as a heat exchange medium, which includes the following steps:

1) Pass the sludge into the sludge thermal hydrolysis tank for the thermal hydrolysis reaction, and the high temperature heat transfer oil flowing in the heating coil on the outer wall of the sludge thermal hydrolysis tank provides the heat required for the thermal hydrolysis reaction;

2) The thermally hydrolyzed sludge is transported by the material pump to the heat exchanger for preheating, and then enters the reactor to mix with oxygen to undergo supercritical water oxidation reaction, releasing a lot of heat;

3) The reacted high-temperature fluid first passes through a heat exchanger for the first stage of heat exchange, and transfers the heat directly to the thermally hydrolyzed sludge; then passes through the heat transfer oil heat exchanger to transfer the remaining heat to the heat transfer oil; The heat transfer oil enters the heating coil on the outer wall of the sludge thermal hydrolysis tank to heat the sludge thermal hydrolysis tank to ensure the progress of the thermal hydrolysis reaction;

4) After the heat transfer reaction is completely completed, the fluid is close to normal temperature, returns to normal pressure through the back pressure valve, and then completes the separation of gas-liquid-solid components in the three-phase separator to achieve discharge standards.

Preferably, the sludge thermal hydrolysis tank includes a connected first sludge thermal hydrolysis tank and a second sludge thermal hydrolysis tank;

It also includes an electric heater connected to the shell-side outlet of the heat transfer oil heat exchanger. The outlet of the electric heater is connected to the heating coil inlet on the outer wall of the second sludge thermal hydrolysis tank. The outlet of the heating coil is connected with the inlet of the heating coil on the outer wall of the first sludge thermal hydrolysis tank, and the outlet of the heating coil on the outer wall of the first sludge thermal hydrolysis tank is connected with an oil-gas separator through a pipeline;

The outlet of the oil-air separator is connected with a filter through a pipeline, and the outlet of the filter is connected to the shell side inlet of the heat transfer oil heat exchanger through a pipeline at the outlet end of the circulating pump, and the shell side outlet of the heat transfer oil heat exchanger and the electric heater Connected

In step 1), the sludge is first transported into the first sludge thermal hydrolysis tank, after completing a certain degree of thermal hydrolysis, it enters the second sludge thermal hydrolysis tank to complete the complete thermal hydrolysis reaction;

In step 3), the heat transfer oil is heated by the heat transfer oil heat exchanger and then enters the electric heater for secondary heating. When reaching a predetermined temperature, it enters the heating coil on the outer wall of the second sludge thermal hydrolysis tank, and transfers the heat to the second sewage. The sludge in the sludge thermal hydrolysis tank then continues to flow into the heating coil on the outer wall of the first sludge thermal hydrolysis tank to heat the sludge in the first sludge thermal hydrolysis tank; then, it flows through the first sludge The heat-conducting oil from the mud thermal hydrolysis tank enters the oil-gas separator, then passes through the filter and the circulating pump in turn, then returns to the heat-conducting oil heat exchanger, and continues to be heated, completing a cycle.

Preferably, another pipeline at the outlet end of the circulating pump is connected to the electric heater, and an automatic regulating valve is provided on the pipeline; the opening of the automatic regulating valve is interlocked with the outlet temperature of the heat transfer oil heat exchanger shell, which can be adjusted through the valve The opening degree controls the amount of heat transfer oil flowing through the heat transfer oil heat exchanger, so that the temperature of the shell side fluid outlet of the heat transfer oil heat exchanger is maintained at the set value.

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

The sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium disclosed by the present invention uses heat transfer oil with good fluidity and small heat capacity as the heat exchange medium, and the sludge thermal hydrolysis tank in the supercritical water oxidation device The internal heating method is changed to external wall surface heating, which can solve the problem of sludge scaling and coking on the surface of the internal coil heating type sludge thermal hydrolysis tank. Comparisons in terms of economy, safety and reliability , The significant advantages of the system of the present invention are obtained, and the results are as follows:

First, economy: the prior art adopts the method of installing a high-pressure coil in the tank. Because the fluid after the supercritical water oxidation reaction generally has a large amount of inorganic salt ions generated by the reaction and oxygen involved in the reaction, it is highly corrosive and It is a high-temperature and high-pressure fluid, and only high-grade metal materials are needed as equipment materials, and a larger wall thickness needs to be selected for pressure and corrosion resistance. However, the present invention uses relatively low-temperature, non-corrosive, and normal-pressure heat transfer oil as the heat exchange medium, and can use thinner-walled ordinary stainless steel or even carbon steel as equipment materials, which significantly reduces the cost.

Second, safety: The prior art adopts a scheme of installing high-pressure heating coils in a sealed sludge thermal hydrolysis tank, and cannot monitor the wall thickness reduction of the internal coils in real time. If there is corrosion perforation, leakage or even stress Corrosion and cracking will cause serious dangerous accidents in the chemical system "high-low series", that is, high-pressure fluid is discharged into a low-pressure confined space, which may cause the explosion of the entire thermal hydrolysis tank, which is extremely dangerous. However, if the heating coil on the outer wall of the sludge thermal hydrolysis tank disclosed in the present invention is used, the above potential safety accidents will not occur.

Third, reliability: using the internal coil heating method, the sludge will coke and scale on the internal coil of the thermal hydrolysis tank, which will seriously affect the heat exchange effect. Since the sludge thermal hydrolysis tank needs to reach a high temperature higher than 100℃, a constant pressure device must be installed in the tank to avoid high temperature vaporization of the sludge, which means that the device is airtight during operation and cannot be simply disassembled. To clean up the dirt on the surface of the pipeline, it can only be forced to shut down for cleaning, which seriously affects the safety and stability of system operation. The heating coil on the outer wall of the sludge thermal hydrolysis tank disclosed in the present invention can effectively avoid the above-mentioned problems and improve the reliability of the system.

Furthermore, the sludge thermal hydrolysis tank is equipped with a stirrer, which can drive the sludge in the tank to continuously rotate and stay in a flowing state. On the one hand, it avoids deposition, on the other hand, it increases the heat transfer coefficient and strengthens the heat transfer.

The present invention also discloses a method for treating sludge using the above-mentioned system of the present invention. The heat released by the supercritical water oxidation reaction through the heat transfer oil heat exchanger uses the heat transfer oil as the heat exchange medium to convert the heat of the high-pressure, highly corrosive heat source It becomes a normal pressure and non-corrosive heat source, which improves the safety, economy, and reliability of the system; therefore, the heat transfer oil is used as the heat exchange medium to perform sludge thermal hydrolysis and finally complete the supercritical water oxidation reaction , The method to achieve the emission standards can fully realize the long-term safe and stable operation of the system.

Description of the drawings

Fig. 1 is a schematic structural diagram of the sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium of the present invention.

Among them, 1 is the first sludge thermal hydrolysis tank, 2 is the second sludge thermal hydrolysis tank, 3 is the material pump, 4 is the heat exchanger, 5 is the reactor, 6 is the heat transfer oil heat exchanger, 7 is the heat exchanger Back pressure valve, 8 is a three-phase separator, 9 is an expansion tank, 10 is an oil and gas separator, 11 is a filter, 12 is a circulating pump, 13 is an electric heater, and 14 is an automatic regulating valve.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is a part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and not necessarily used to describe a specific sequence or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations of them are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to the clearly listed Those steps or units may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or equipment.

The present invention will be described in further detail below in conjunction with the accompanying drawings:

Refer to Figure 1, which is a sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium of the present invention, which includes a sludge thermal hydrolysis pretreatment unit, a heat transfer oil heat exchange unit and a supercritical water oxidation unit.

The sludge thermal hydrolysis unit includes a first sludge thermal hydrolysis tank 1 and a second sludge thermal hydrolysis tank 2. The first sludge thermal hydrolysis tank 1 and the second sludge thermal hydrolysis tank 2 are connected: sludge The raw materials first enter the first sludge thermal hydrolysis tank 1;

The supercritical water oxidation reaction unit includes a heat exchanger 4, a reactor 5, a heat transfer oil heat exchanger 6, a back pressure valve 7 and a three-phase separator 8. The pipe connecting the sludge thermal hydrolysis tank 2 and the heat exchanger 4 There is a material pump 3 on the road, the pipe side outlet end of the heat exchanger 4 is connected with the inlet end of the reactor 5, the outlet end of the reactor 5 is connected with the shell side inlet end of the heat exchanger 4, and the shell side of the heat exchanger 4 The outlet is connected to the pipe side inlet end of the heat transfer oil heat exchanger 6, the pipe side outlet end of the heat transfer oil heat exchanger 6 is connected to the inlet of the back pressure valve 7, and the outlet of the back pressure valve 7 is connected to the inlet of the three-phase separator 8, The top of the three-phase separator 8 is provided with an exhaust port, the bottom is provided with a slag discharge port, and the cylinder wall is provided with a liquid discharge port. All three phases can achieve standard discharge.

The heat transfer oil unit includes a heat transfer oil heat exchanger 6, an electric heater 13, a filter 11, a circulating pump 12, an automatic regulating valve 14, an expansion tank 9, and an oil and gas separator 10. The outlet of the oil-air separator 10 is connected with the inlet of the filter 11, the outlet of the filter 11 is connected with the inlet of the circulating pump 12, the outlet of the circulating pump 12 is connected with the shell side inlet of the heat transfer oil heat exchanger 6, and the heat transfer oil heat exchanger The shell-side outlet of 6 is connected to the electric heater 13, and there is a way from the outlet of the circulating pump 12 directly connected to the electric heater 13. There is an automatic regulating valve 14 between the two, and the outlet of the electric heater 13 is connected to the second The outer wall coil inlet of the sludge thermal hydrolysis tank 2 is connected, and the outer wall coil outlet of the second sludge thermal hydrolysis tank 2 is connected with the outer wall coil inlet of the first sludge thermal hydrolysis tank 1. The outlet of the outer wall coil of the hydrolysis tank 1 is connected with the inlet of the oil-gas separator 10, the top of the oil-gas separator 10 has a gas outlet connected with the expansion tank 9, and the heat transfer oil heat exchanger 6 is between the shell side outlet and the inlet of the electric heater 13 There is also an outlet connected to the expansion tank 9 on the pipeline.

The first sludge thermal hydrolysis tank 1 and the second sludge thermal hydrolysis tank 2 are provided with a stirring device inside, and a heating coil is provided on the outer wall surface, and the heat transfer oil flows in the outer heating coil to transfer heat to the tank On the body wall, the sludge in the tank is driven to rotate by the stirring device.

The automatic regulating valve 14 is pneumatic or electric.

The invention also discloses a method for thermally hydrolyzing sludge based on the above-mentioned system using heat transfer oil as a heat exchange medium, and finally completing the supercritical water oxidation reaction and realizing discharge compliance, which includes the following steps:

1) The sludge raw material is first transported into the first sludge thermal hydrolysis tank 1, after completing a certain degree of thermal hydrolysis, it enters the second sludge thermal hydrolysis tank 2 to complete the complete thermal hydrolysis reaction. At this time, the heat of the sludge thermal hydrolysis tank is provided by the high-temperature heat transfer oil flowing in the heating coil arranged outside the tank.

2) The thermally hydrolyzed sludge is transported to the heat exchanger 4 through the material pump 3 for preheating, and then enters the reactor 5 to mix with oxygen to undergo supercritical water oxidation reaction, and the reacted high-temperature fluid first passes through the heat exchanger 4 The first stage of heat exchange transfers the heat directly to the thermally hydrolyzed sludge. Then, the reacted fluid with a considerable amount of heat still flows through the heat transfer oil heat exchanger 6 to transfer the heat to the heat transfer oil.

3) After the heat transfer reaction is completely completed, the fluid is now close to normal temperature, and returns to normal pressure through the back pressure valve 7 to reduce the pressure, and then complete the separation of gas, liquid and solid components in the three-phase separator 8 to achieve standard discharge.

4) The implementation method of the heat transfer oil subsystem is introduced here: the heat transfer oil is heated by the heat transfer oil heat exchanger 6 and then enters the electric heater 13 for secondary heating, and then reaches the predetermined temperature and enters the second sludge thermal hydrolysis tank 2 The coil on the outer wall transfers heat to the sludge in the second sludge thermal hydrolysis tank 2 and then continues to flow to the coil on the outer wall of the first thermal hydrolysis tank 1 to heat the sludge in the first thermal hydrolysis tank 1. mud. At this time, the agitators in the two sludge thermal hydrolysis tanks are all in the starting state. Subsequently, the heat-conducting oil flowing through the first thermal hydrolysis tank 1 enters the oil-air separator 10, then passes through the filter 11 and the circulating pump 12 and then returns to the heat-conducting oil heat exchanger 6 to continue to be heated to complete a cycle.

In the step 4), before the heat transfer oil enters the heat transfer oil heat exchanger 6, there is a short-circuit bypass controlled by the automatic regulating valve 14. The opening of the automatic regulating valve 14 is the same as the shell side outlet of the heat transfer oil heat exchanger 6 The temperature interlock can control the amount of heat transfer oil flowing through the heat transfer oil heat exchanger by adjusting the valve opening, so that the temperature of the shell side fluid outlet of the heat transfer oil heat exchanger 6 is maintained at a set value.

Those skilled in the art can understand that the embodiments described above are all exemplary, and those skilled in the art can make improvements. The structures described in the various embodiments do not have structural or principle differences. In case of conflict, free combination can be made, thereby solving the technical problem of the present invention.

After describing the embodiments of the present invention in detail, those skilled in the art can clearly understand that various changes and changes can be made without departing from the scope and spirit of the appended claims, and the present invention is not limited to the specification. The exemplary embodiments are implemented in the examples.

Claims

A sludge supercritical water oxidation system using heat transfer oil as a heat exchange medium is characterized by comprising a sludge thermal hydrolysis tank, a heat exchanger (4), a reactor (5) and a heat transfer oil heat exchanger (6) );

Among them, the sludge thermal hydrolysis tank is connected to the heat exchanger (4) through the material pump (3), the pipe side outlet end of the heat exchanger (4) is connected to the inlet end of the reactor (5), and the reactor (5) The outlet end of the heat exchanger (4) is connected to the shell side inlet end of the heat exchanger (4), the shell side outlet of the heat exchanger (4) is connected to the inlet end of the heat transfer oil heat exchanger (6), and the heat transfer oil heat exchanger (6) The outlet end is connected with the heating coil set on the outer wall of the sludge thermal hydrolysis tank;

It also includes a back pressure valve (7) and a three-phase separator (8) that are connected to the pipe side outlet of the heat transfer oil heat exchanger (6) in sequence, and the pipe side outlet end of the heat transfer oil heat exchanger (6) and the back pressure valve (7) The inlet is connected. The outlet of the back pressure valve (7) is connected with the inlet of the three-phase separator (8). The top of the three-phase separator (8) is provided with an exhaust port, and the bottom is provided with a slag discharge port. The wall is provided with a liquid drain.
The sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium according to claim 1, wherein the sludge thermal hydrolysis tank comprises a connected first sludge thermal hydrolysis tank (1) and The second sludge thermal hydrolysis tank (2) and the material pump (3) are arranged on the pipeline connecting the second sludge thermal hydrolysis tank (2) and the heat exchanger (4).
The sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium according to claim 2, characterized in that it further comprises an electric heater (13) connected to the shell side outlet of the heat transfer oil heat exchanger (6) , The outlet of the electric heater (13) is connected with the heating coil inlet on the outer wall of the second sludge thermal hydrolysis tank (2), and the heating coil outlet on the outer wall of the second sludge thermal hydrolysis tank (2) is connected with the first sewage The inlet of the heating coil on the outer wall of the sludge thermal hydrolysis tank (1) is connected, and the outlet of the heating coil on the outer wall of the first sludge thermal hydrolysis tank (1) is connected with an oil-gas separator (10) through a pipeline;

The outlet of the oil and gas separator (10) is connected with a filter (11) through a pipeline, and the outlet of the filter (11) is connected to the shell side of the heat transfer oil heat exchanger (6) through a pipeline at the outlet end of the circulating pump (12) The inlet, the shell-side outlet of the heat transfer oil heat exchanger (6) is connected to the electric heater (13), and the other pipeline at the outlet end of the circulating pump (12) is connected to the electric heater (13), and an automatic Regulating valve (14).
The sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium according to claim 3, characterized in that it further comprises an expansion tank (9), a gas outlet at the top of the oil-gas separator (10) and the expansion tank ( 9) Connect.
The sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium according to claim 4, characterized in that the pipe between the shell side outlet of the heat transfer oil heat exchanger (6) and the inlet of the electric heater (13) A branch connected with the expansion tank (9) is provided on the road.
The sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium according to any one of claims 1 to 5, wherein a stirring device is provided in the sludge thermal hydrolysis tank.
The sludge treatment method based on the sludge supercritical water oxidation system using heat transfer oil as the heat exchange medium according to claim 1, characterized in that it comprises the following steps:

1) Pass the sludge into the sludge thermal hydrolysis tank for the thermal hydrolysis reaction, and the high temperature heat transfer oil flowing in the heating coil on the outer wall of the sludge thermal hydrolysis tank provides the heat required for the thermal hydrolysis reaction;

2) The thermally hydrolyzed sludge is transported by the material pump to the heat exchanger (4) for preheating, and then enters the reactor (5) to mix with oxygen to undergo supercritical water oxidation reaction, releasing a large amount of heat;

3) The reacted high-temperature fluid first passes through the heat exchanger (4) for the first stage of heat exchange, and directly transfers the heat to the sludge after thermal hydrolysis; then passes through the heat transfer oil heat exchanger (6) to remove the remaining The heat is transferred to the heat transfer oil; the heat transfer oil enters the heating coil on the outer wall of the sludge thermal hydrolysis tank to heat the sludge thermal hydrolysis tank to ensure the progress of the thermal hydrolysis reaction;

4) After the heat transfer reaction is completed, the fluid is close to normal temperature, returns to normal pressure through the back pressure valve (7), and then completes the separation of gas, liquid and solid components in the three-phase separator (8) to achieve standard discharge.
The sludge treatment method according to claim 7, wherein the sludge thermal hydrolysis tank comprises a first sludge thermal hydrolysis tank (1) and a second sludge thermal hydrolysis tank (2) connected;

It also includes an electric heater (13) connected to the shell side outlet of the heat transfer oil heat exchanger (6), the outlet of the electric heater (13) and the heating coil inlet on the outer wall of the second sludge thermal hydrolysis tank (2) The outlet of the heating coil on the outer wall of the second sludge thermal hydrolysis tank (2) is connected to the inlet of the heating coil on the outer wall of the first sludge thermal hydrolysis tank (1), and the first sludge thermal hydrolysis tank (1) The outlet of the heating coil on the outer wall is connected with an oil-gas separator (10) through a pipeline;

The outlet of the oil and gas separator (10) is connected with a filter (11) through a pipeline, and the outlet of the filter (11) is connected to the shell side of the heat transfer oil heat exchanger (6) through a pipeline at the outlet end of the circulating pump (12) The inlet, the shell side outlet of the heat transfer oil heat exchanger (6) is connected with the electric heater (13);

In step 1), the sludge is first transported into the first sludge thermal hydrolysis tank (1), after completing a certain degree of thermal hydrolysis, it enters the second sludge thermal hydrolysis tank (2) to complete the complete thermal hydrolysis reaction ；

In step 3), the heat-conducting oil is heated by the heat-conducting oil heat exchanger (6) and then enters the electric heater (13) for secondary heating, and reaches a predetermined temperature and enters the heating coil on the outer wall of the second sludge thermal hydrolysis tank (2) The heat is transferred to the sludge in the second sludge thermal hydrolysis tank (2), and then continues to flow into the heating coil on the outer wall of the first sludge thermal hydrolysis tank (1) to heat the first sludge thermal The sludge in the hydrolysis tank (1); subsequently, the heat transfer oil flowing through the first sludge thermal hydrolysis tank (1) enters the oil-gas separator (10), and then passes through the filter (11) and the circulating pump (12) ) Then return to the heat transfer oil heat exchanger (6), continue to be heated, and complete a cycle.
The sludge treatment method according to claim 8, characterized in that another pipeline at the outlet end of the circulating pump (12) is connected to an electric heater (13), and an automatic regulating valve (14) is provided on the pipeline;

The opening of the automatic regulating valve (14) is interlocked with the outlet temperature of the heat transfer oil heat exchanger (6). The amount of heat transfer oil flowing through the heat transfer oil heat exchanger (6) can be controlled by adjusting the valve opening, so that the heat transfer oil The temperature of the shell side fluid outlet of the heat exchanger (6) is maintained at a set value.