Anti-corrosion and anti-blocking continuous salt-discharging supercritical water oxidation reaction kettle

Abstract

The invention discloses an anti-corrosion and anti-blocking continuous salt-discharging supercritical water oxidation reaction kettle, and belongs to the technical field of supercritical water oxidation reaction devices. The invention aims to provide the supercritical water oxidation reaction kettle which is resistant to high pressure and corrosion in structure and can discharge salt in time. According to the technical scheme, an isolation sleeve and a conical funnel sleeve are both located in a vertical kettle body, the upper end of the isolation sleeve is fixed to the top of the vertical kettle body, the conical funnel sleeve is located below the isolation sleeve, and a funnel pipe part of the conical funnel sleeve is inserted into a salt outlet in the bottom of the vertical kettle body; a feeding pipe is inserted into the isolating sleeve from the top of the vertical kettle body; a wastewater inlet and an oxidant inlet are formed in the upper part of the feeding pipe; the sleeve cooler is positioned below the vertical kettle body, a funnel pipe outlet of the conical funnel sleeve is communicated into the sleeve cooler, and a salt discharge port is formed in the bottom of the sleeve cooler and is connected with a salt discharge valve. The device is used for treating high-salt organic wastewater, and anti-corrosion continuous salt discharging is achieved.

Description

Technical Field

[0001] The invention discloses an anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor, belonging to the technical field of supercritical water oxidation reaction devices. Background Art

[0002] For organic wastewater with high concentration, difficult biodegradation, high salinity, toxicity and harmfulness, traditional treatment technology cannot achieve the requirements of efficient and harmless treatment. Therefore, supercritical water oxidation technology (SCWO) has received widespread attention at home and abroad.

[0003] Supercritical water refers to water whose temperature and pressure are higher than its critical point (T = 374.15 ° C, P = 22.12 MPa). Supercritical water has some advantages of both liquid and gaseous water. In this state, only a small amount of hydrogen bonds exist, and the dielectric constant is similar to that of non-polar organic solvents. It has a high diffusion coefficient and low viscosity. Organic matter, oxidants (oxygen, etc.) and supercritical water are mutually soluble in each other to achieve a homogeneous phase, which greatly reduces the mass transfer resistance. Inorganic salts have extremely low solubility in supercritical water and are easily precipitated.

[0004] SCWO uses the special property of supercritical water as a good solvent for both organic matter and oxidants. Organic matter undergoes homogeneous oxidation reaction in an oxygen-rich environment, rapidly and thoroughly destroying the organic matter and converting it into harmless small molecule compounds and inorganic salts such as H2O and CO2. The organic matter is treated thoroughly, without secondary pollution, and can achieve self-heating, waste heat recovery, and low operating costs. There are commercial SCWO devices in operation abroad, while most of them are still in the laboratory research stage in China, with only a few pilot devices.

[0005] Usually, high-concentration organic wastewater that is difficult to biodegrade contains a large amount of inorganic salts, especially F - , Cl - 、SO4 2- PO4 3- Corrosive ions such as ions, with a mass content of more than 10wt%, will cause pitting, stress corrosion, erosion corrosion and other corrosion problems on the contact surface of the system (such as the reactor wall) in a high temperature, high pressure and high oxygen environment. In addition, due to the extremely low solubility of inorganic salts in supercritical water, they will precipitate and deposit on the inner surface of the reactor during the supercritical water oxidation process, causing serious blockage of the reactor and pipelines, which will greatly reduce the reliability and service life of the SCWO device. This is also the main technical obstacle faced in the supercritical water oxidation treatment of saline organic wastewater. The existing desalination methods (multi-effect evaporation, electrodialysis, reverse osmosis, ion exchange, electrosorption, etc.) are difficult to use in the SCWO system of high-salt organic wastewater, which greatly limits the promotion and application of SCWO technology.

[0006] The supercritical water oxidation technology is used to continuously treat high-salinity organic wastewater. The reactor is the key link of the entire treatment device. The current bottleneck problems are that inorganic salt ions corrode the reactor, shortening the life of the equipment; the existing supercritical water oxidation reactor mainly uses corrosion-resistant metal materials including stainless steel, nickel-based alloys, titanium alloys, etc., but these materials are difficult to resist common F - , Cl - 、SO4 2- PO4 3- Plasma corrosion is particularly prominent under high temperature, high pressure and high oxygen conditions. Reactors are not only required to withstand high pressure but also be corrosion-resistant. At present, the materials used in domestic reactors are either able to withstand pressure but not corrosion-resistant, or are corrosion-resistant but cannot withstand high pressure due to their brittleness, resulting in a situation where there is no choice of reactor materials. Second, the reactor outlet is blocked due to inorganic salt deposition. If the salt cannot be discharged from the reactor in time, it will make it difficult for the device to operate normally and continuously. Most of the salt formed in the supercritical water oxidation reaction of high-salt organic wastewater is deposited at the bottom of the reactor. Due to the continuity of the reaction process, a large amount of inorganic salts are formed and accumulate at the bottom of the reactor, which can easily block the reactor and cause the equipment to stop.

[0007] Therefore, for the treatment of high-concentration salt-containing organic wastewater SCWO, how to improve the reactor structure to avoid direct contact between the reactor's pressure-resistant metal materials and the treatment medium, and how to discharge inorganic salts in time to prevent clogging, are the core issues that need to be urgently solved in the future of supercritical water oxidation treatment of organic wastewater. Summary of the invention

[0008] In view of the deficiencies in the prior art, the object of the present invention is to provide a supercritical water oxidation reactor which is structurally resistant to both high pressure and corrosion and can discharge salt in a timely manner.

[0009] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a corrosion-resistant and anti-blocking continuous salt-discharging supercritical water oxidation reactor, comprising a vertical reactor body, an isolation sleeve, a conical funnel sleeve, a feed pipe and a sleeve cooler, wherein the isolation sleeve and the conical funnel sleeve are both located inside the vertical reactor body, the upper end of the isolation sleeve is fixed to the top of the vertical reactor body, and the other parts of the isolation sleeve are not in contact with the inner wall of the vertical reactor body, the conical funnel sleeve is located below the isolation sleeve, the funnel tube part of the conical funnel sleeve is inserted into the salt outlet at the bottom of the vertical reactor body, and there is a gap between the funnel mouth part of the conical funnel sleeve and the inner wall of the vertical reactor body;

[0010] The feed pipe is inserted into the interior of the isolation sleeve from the top of the vertical kettle body, and a wastewater inlet and an oxidant inlet are arranged on the upper part of the feed pipe;

[0011] The jacket cooler is located below the vertical kettle body. The jacket cooler includes an inner jacket and an outer jacket. The inner jacket is sleeved inside the outer jacket. The tops of the inner jacket and the outer jacket are fixed to the bottom of the vertical kettle body. The funnel pipe outlet of the conical funnel jacket leads to the interior of the inner jacket. The bottoms of the inner jacket and the outer jacket are provided with connected salt discharge ports. A coolant channel is provided between the inner jacket and the outer jacket. A coolant inlet is provided at the bottom of the outer jacket, and a coolant outlet is provided at the top.

[0012] The salt discharge port is connected to the salt discharge valve.

[0013] Furthermore, a discharge port is provided at the top or upper part of the side wall of the vertical kettle body, the discharge port is connected to the condenser through a pipeline, and a back pressure valve is connected to the outlet of the condenser.

[0014] Furthermore, the upper portion of the feed pipe is also provided with a catalyst inlet,

[0015] Furthermore, the pipe connecting the discharge port and the condenser is wound around the pipe connected to the catalyst inlet.

[0016] Furthermore, the condenser is replaced by a waste heat recovery device.

[0017] Furthermore, the length of the isolation sleeve is 1 / 2 to 4 / 5 of the height of the inner cavity of the vertical kettle.

[0018] Furthermore, a heating jacket is provided on the outer side wall of the vertical kettle body.

[0019] Furthermore, a pressure sensor and a temperature sensor for monitoring the pressure and temperature in the isolation casing are also provided on the top of the vertical kettle body.

[0020] Furthermore, the material of the isolation sleeve and the conical funnel sleeve is SiC.

[0021] Furthermore, the coolant used in the sleeve cooler is water.

[0022] Compared with the prior art, the present invention has the following beneficial effects.

[0023] 1. Based on the traditional reactor structure, the present invention adds an isolation sleeve and a conical funnel sleeve, so that the vertical reactor body part that bears pressure in the reactor is not corroded, and the part that contacts with corrosive substances is not under pressure, which facilitates the selection of materials for various parts of the reactor and greatly extends the service life of the reactor.

[0024] 2. The present invention also provides a jacket cooler and a back pressure valve. The inorganic salt after cooling has good solubility, and the concentrated salt solution has good fluidity and is very easy to discharge. The salt discharge valve can be opened during the wastewater treatment process, and the system pressure can be regulated and stabilized by the back pressure valve, so that the inorganic salt produced by the reaction can be continuously discharged, thereby solving the blockage problem of the reactor.

[0025] 3. The present invention provides a feed pipe, and a wastewater inlet, an oxidant inlet and a catalyst inlet are provided on the feed pipe. The feed pipe can mix the wastewater and the oxidant in advance, shortening the time for preparing the wastewater reaction. In addition, the catalyst inlet can be used to introduce the catalyst under special circumstances to enhance the reaction process and better treat the wastewater. The pipe at the discharge port is wound around the catalyst pipe, which can preheat the catalyst and make the reaction process smoother. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0027] Figure 1 It is a structural diagram of embodiment 1 of the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of the second embodiment of the present invention.

[0029] In the figure: 1 is a vertical kettle body, 2 is an isolation sleeve, 3 is a conical funnel sleeve, 4 is a feed pipe, 5 is a sleeve cooler, 6 is a wastewater inlet, 7 is an oxidant inlet, 8 is an inner sleeve, 9 is an outer sleeve, 10 is a salt discharge port, 11 is a coolant inlet, 12 is a coolant outlet, 13 is a salt discharge valve, 14 is a discharge port, 15 is a condenser, 16 is a back pressure valve, 17 is a catalyst inlet, 18 is a heating jacket, 19 is a pressure sensor, and 20 is a temperature sensor. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The present invention provides the following embodiments.

[0032] Embodiment 1

[0033] like Figure 1As shown, the present invention is a corrosion-resistant and anti-blocking continuous salt-removing supercritical water oxidation reactor, comprising a vertical reactor body 1, an isolation sleeve 2, a conical funnel sleeve 3, a feed pipe 4 and a sleeve cooler 5, wherein the isolation sleeve 2 and the conical funnel sleeve 3 are both located inside the vertical reactor body 1, the upper end of the isolation sleeve 2 is fixed to the top of the vertical reactor body 1, and the other parts of the isolation sleeve 2 are not in contact with the inner wall of the vertical reactor body 1, the conical funnel sleeve 3 is located below the isolation sleeve 2, the funnel tube part of the conical funnel sleeve 3 is inserted into the salt outlet at the bottom of the vertical reactor body 1, and there is a gap between the funnel mouth part of the conical funnel sleeve 3 and the inner wall of the vertical reactor body 1;

[0034] The feed pipe 4 is inserted into the interior of the isolation sleeve 2 from the top of the vertical kettle body 1, and a wastewater inlet 6 and an oxidant inlet 7 are provided on the upper part of the feed pipe 4;

[0035] The jacket cooler 5 is located below the vertical kettle body 1. The jacket cooler 5 includes an inner jacket 8 and an outer jacket 9. The inner jacket 8 is sleeved in the outer jacket 9. The tops of the inner jacket 8 and the outer jacket 9 are fixed to the bottom of the vertical kettle body 1. The funnel outlet of the conical funnel jacket 3 leads to the inner jacket 8. The bottoms of the inner jacket 8 and the outer jacket 9 are provided with a connected salt discharge port 10. A coolant channel is provided between the inner jacket 8 and the outer jacket 9. A coolant inlet 11 is provided at the bottom of the outer jacket 9, and a coolant outlet 12 is provided at the top.

[0036] The salt discharge port 10 is connected to a salt discharge valve 13 .

[0037] The top or upper part of the side wall of the vertical kettle body 1 is provided with a discharge port 14 , which is connected to a condenser 15 through a pipeline, and a back pressure valve 16 is connected to the outlet of the condenser 15 .

[0038] The condenser 15 is replaced by a waste heat recovery device.

[0039] The length of the isolation sleeve 2 is 1 / 2 to 4 / 5 of the height of the inner cavity of the vertical kettle body 1 .

[0040] A heating jacket 18 is provided on the outer side wall of the vertical kettle body 1 .

[0041] The top of the vertical kettle body 1 is also provided with a pressure sensor 19 and a temperature sensor 20 for monitoring the pressure and temperature in the isolation sleeve.

[0042] The material of the isolation sleeve 2 and the conical funnel sleeve 3 is SiC.

[0043] The cooling liquid used in the jacket cooler 5 is water.

[0044] Embodiment 2

[0045] like Figure 2As shown, the structure of the second embodiment is based on the structure of the first embodiment, and the following structures are added:

[0046] A catalyst inlet 17 is also provided at the upper portion of the feed pipe 4 .

[0047] The pipe connecting the discharge port 14 and the condenser 15 is wound around the pipe connected to the catalyst inlet 17 .

[0048] In the present invention, the oxidant is generally oxygen.

[0049] The invention meets the requirements of high temperature and high pressure corrosion resistance, anti-clogging and continuous salt discharge of the reactor by adjusting the structure of the reactor.

[0050] 1. The following is an explanation of how to solve the corrosion resistance problem of the reactor by improving the structure.

[0051] Firstly, the present invention adds a coaxial isolation sleeve 2 at the top of the vertical kettle body 1. The length of the isolation sleeve 2 is determined according to the specific type of wastewater to be treated, and is generally between 1 / 2 and 4 / 5 of the height of the inner cavity of the vertical kettle body 1.

[0052] Wastewater and oxygen etc. enter the isolation sleeve 2 from the corresponding inlets on the feed pipe 4, and the supercritical water oxidation reaction is carried out in the isolation sleeve 2. The internal temperature range of the vertical kettle body 1 is 400-650°C, and the reaction pressure range is 20-35Mpa. Since the isolation sleeve 2 is fixed inside the vertical kettle body 1, although it is in a high-pressure environment, it does not need to bear pressure because the pressure on its inner and outer tube walls is consistent. Therefore, as long as the material of the isolation sleeve 2 meets the high temperature resistance and corrosion resistance, it can meet the harsh environmental requirements of the supercritical water oxidation reaction, and the range of sleeve material selection is greatly broadened. For example, SiC with good thermal conductivity, high temperature resistance and strong corrosion resistance can be selected as the material of the isolation sleeve 2.

[0053] For the corrosion protection of the lower part and the bottom of the vertical kettle body 1, the present invention adopts a coaxial conical funnel sleeve 3 lined at the lower part and the bottom outlet of the vertical kettle body 1, and its size meets the following conditions:

[0054] Φ1﹤Φ2﹤Φ3

[0055] 10mm﹤H﹤100mm

[0056] Among them, Φ1 is the outer diameter of the isolation sleeve 2, Φ2 is the outer diameter of the funnel mouth of the conical funnel sleeve 3, Φ3 is the inner diameter of the vertical kettle body 1, and H is the distance between the lower end of the isolation sleeve 2 and the conical funnel sleeve 3.

[0057] Since there is a gap between the conical funnel sleeve 3 and the inner wall of the vertical kettle body 1, the inner and outer conical walls are not under pressure. The material can also be SiC, ceramics, etc., thereby solving the corrosion problem of the lower part and outlet of the vertical kettle body 1.

[0058] Part of the salt precipitated during the supercritical water oxidation reaction is deposited on the inner wall of the isolation sleeve 2. This part of the salt can be removed by stopping the machine regularly and pumping in 10-90°C clean water to dissolve the salt or adding a descaling agent. The remaining inorganic salts will settle at the bottom of the kettle and be continuously discharged with the material flow. In this way, the inner wall of the vertical kettle body 1 is less in contact with the reaction medium, achieving the purpose of slowing down or preventing corrosion.

[0059] Second, the following describes how to solve the problem of reactor blockage through structural improvement.

[0060] On the one hand, the present invention arranges a jacket cooler 5 and a salt discharge valve at the bottom salt outlet of the vertical kettle body 1, and the high-temperature and high-pressure salt sediment flows through the jacket cooler 5 to condense into a high-pressure and low-temperature concentrated salt solution. After cooling, the temperature of the concentrated salt solution is less than 50° C. At this time, the inorganic salt has good solubility, resulting in good fluidity of the concentrated salt solution and easy discharge. As the supercritical water oxidation reaction proceeds, the generated salt can be continuously discharged, thereby preventing the reactor from being blocked.

[0061] On the other hand, after the supercritical water oxidation process reacts in the isolation sleeve 2, the supercritical fluid is discharged through the discharge port 14 at the top of the vertical kettle body 1. A condenser 15 or a waste heat recovery device is provided on the discharge pipeline. The temperature of the fluid after condensation or waste heat recovery is less than 50°C. A back pressure valve 16 is installed after the condenser or the waste heat recovery device. The adjustable pressure range of the back pressure valve 16 is 0 to 35 MPa. The pressure of the reactor and its system is maintained constant through the coordinated regulation of the back pressure valve 16 and the salt discharge valve 13 at the bottom of the sleeve cooler 5. The salt discharge port 10 is continuously discharged by utilizing the pressure difference between the inside and outside of the equipment, thereby better solving the problem of blockage.

[0062] On the basis of the above-mentioned anti-corrosion and anti-blocking, the corrosion of the vertical kettle body 1 will be greatly reduced, and for this reason, the material of the vertical kettle body 1 can be selected from stainless steel material lined with nickel-based alloy. In this way, the cost of the reactor can be significantly reduced.

[0063] In addition, in the present invention, a feed pipe 4 is provided, and the waste liquid and oxygen first enter the feed pipe 4 through the waste water inlet 6 and the oxidant inlet 7 thereon, and then enter the interior of the isolation sleeve 2 after being mixed in advance, thus effectively shortening the time required for waste water reaction preparation.

[0064] In the second embodiment, a catalyst inlet 17 is also provided on the feed pipe 4, and the pipe connecting the discharge port 14 on the vertical kettle body 1 and the condenser 15 is wound around the pipe connected to the catalyst inlet 17. In some special wastewater treatment processes, the reaction process can be enhanced by introducing a catalyst, and the catalyst can be preheated.

[0065] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A corrosion-resistant and anti-blocking continuous salt removal supercritical water oxidation reactor, characterized in that: The invention comprises a vertical kettle body (1), an isolating sleeve (2), a conical funnel sleeve (3), a feed pipe (4) and a sleeve cooler (5), wherein the isolating sleeve (2) and the conical funnel sleeve (3) are both located inside the vertical kettle body (1), the upper end of the isolating sleeve (2) is fixed to the top of the vertical kettle body (1), the other parts of the isolating sleeve (2) do not contact the inner wall of the vertical kettle body (1), the conical funnel sleeve (3) is located below the isolating sleeve (2), the funnel pipe part of the conical funnel sleeve (3) is inserted into the salt outlet at the bottom of the vertical kettle body (1), and there is a gap between the funnel mouth part of the conical funnel sleeve (3) and the inner wall of the vertical kettle body (1); A feed pipe (4) is inserted into the interior of the isolation sleeve (2) from the top of the vertical kettle body (1), and a wastewater inlet (6) and an oxidant inlet (7) are provided at the upper portion of the feed pipe (4); The jacket cooler (5) is located below the vertical kettle body (1). The jacket cooler (5) comprises an inner jacket (8) and an outer jacket (9). The inner jacket (8) is sleeved inside the outer jacket (9). The tops of the inner jacket (8) and the outer jacket (9) are fixed to the bottom of the vertical kettle body (1). The funnel pipe outlet of the conical funnel jacket (3) leads into the interior of the inner jacket (8). The bottoms of the inner jacket (8) and the outer jacket (9) are provided with a connected salt discharge port (10). A cooling liquid channel is provided between the inner jacket (8) and the outer jacket (9). A cooling liquid inlet (11) is provided at the bottom of the outer jacket (9), and a cooling liquid outlet (12) is provided at the top. The salt discharge port (10) is connected to a salt discharge valve (13).

2. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 1, characterized in that: The top or upper part of the side wall of the vertical kettle body (1) is provided with a discharge port (14), which is connected to a condenser (15) through a pipeline, and a back pressure valve (16) is connected to the outlet of the condenser (15).

3. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 2, characterized in that: The upper portion of the feed pipe (4) is also provided with a catalyst inlet (17).

4. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 3, characterized in that: The pipe connecting the discharge port (14) and the condenser (15) is wound around the pipe connected to the catalyst inlet (17).

5. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 2, 3 or 4, characterized in that: The condenser (15) is replaced by a waste heat recovery device.

6. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 1 or 2, characterized in that: The length of the isolation sleeve (2) is 1 / 2 to 4 / 5 of the height of the inner cavity of the vertical kettle body (1).

7. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 1 or 2, characterized in that: The side wall of the vertical kettle body (1) is sheathed with a heating jacket (18).

8. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 1 or 2, characterized in that: A pressure sensor (19) and a temperature sensor (20) for monitoring the pressure and temperature in the isolation sleeve are also arranged on the top of the vertical kettle body (1).

9. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 1 or 2, characterized in that: The materials of the isolation sleeve (2) and the conical funnel sleeve (3) are SiC.

10. The anti-corrosion and anti-blocking continuous salt removal supercritical water oxidation reactor according to claim 1 or 2, characterized in that: The cooling liquid used in the jacket cooler (5) is water.

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