Feed mixing device and method

Abstract

The invention belongs to the technical field of supercritical water oxidation treatment, and particularly relates to a feed mixing device and method.The feed mixing device is arranged between an upper cover of a supercritical water oxidation reactor and a reaction inner barrel and comprises a mixing cavity (1), a main material pipe (4) arranged in the mixing cavity (1) and an auxiliary material pipe (6) communicated with the mixing cavity (1); organic waste liquid conveyed by the main material pipe (4) and oxygen conveyed by the auxiliary material pipe (6) are fully mixed in the mixing cavity (1) and then enter a reaction area in the reaction inner barrel. According to the feeding and mixing device, through the collaborative design of three-dimensional dispersion and convection impact, the feeding and mixing device is particularly suitable for treatment of organic waste containing radioactive elements, the mixing efficiency is high, the reaction is thorough, and secondary pollution caused by insufficient mixing is thoroughly avoided; the adaptability is high, and the operation is reliable; the system has the advantages of being intelligent, controllable and convenient to operate, does not need additional manual intervention, and meets the strict radioactive waste liquid treatment automation requirement.

Description

Technical Field

[0001] This invention belongs to the field of supercritical water oxidation treatment technology, specifically relating to a feeding and mixing device and method. Background Technology

[0002] In the supercritical water oxidation treatment of radioactive organic waste liquid, the uniformity of mixing of organic waste liquid and oxygen (oxidant) directly determines the reaction efficiency and safety. If the mixing is insufficient, local "oxygen-to-material ratio imbalance" is likely to occur. In some areas, excessive organic waste liquid leads to incomplete reaction (residual organic pollutants, posing a risk of secondary pollution), while in other areas, excessive oxygen and violent reaction cause local overheating (exacerbating thermal stress in the reactor cylinder and shortening equipment life). Therefore, there is an urgent need for a feeding and mixing device that can adapt to supercritical high-pressure and high-temperature conditions, achieve efficient and uniform mixing of materials, and be compatible with the overall reactor system. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing supercritical water oxidation reactor feeding systems, such as "insufficient mixing, poor adaptability, and easy interference with the reaction field," and to provide a feeding and mixing device that is compact in structure, has high mixing efficiency, is resistant to high temperature and high pressure, and is suitable for the treatment of radioactive organic waste liquid.

[0004] To achieve the above objectives, the present invention adopts a feeding and mixing device, which is located between the upper cover of the supercritical water oxidation reactor and the inner cylinder of the reactor. The device includes a mixing chamber, a main material pipe located in the mixing chamber, and an auxiliary material pipe communicating with the mixing chamber. The organic waste liquid transported by the main material pipe and the oxygen transported by the auxiliary material pipe are fully mixed in the mixing chamber and then enter the reaction zone inside the inner cylinder of the reactor.

[0005] Furthermore, the mixing chamber has a cylindrical structure with a smooth inner surface; a first inlet is provided at the top of the mixing chamber; and a guide port is provided at the bottom of the mixing chamber. The guide port is a tapered guide port that guides the mixed material smoothly into the inner reaction cylinder.

[0006] Furthermore, the main material pipe has a straight cylindrical structure, is coaxial with the mixing chamber, has a second inlet at the top, and a sealed structure at the bottom that is close to the guide port of the mixing chamber. Several fluid dispersion holes are provided on the side wall near the bottom of the main material pipe to form a multi-hole dispersion nozzle. The organic waste liquid is input from the second inlet at the top of the main material pipe and output to the mixing chamber through the fluid dispersion holes.

[0007] Furthermore, the fluid dispersion holes are divided into several layers and distributed on different axial sections of the main material pipe. Each layer has several holes evenly arranged along the circumference of the main material pipe. Each fluid dispersion hole is inclined downward at an angle to the axis of the main material pipe, so that the organic waste liquid is dispersed into multiple oblique fine streams that cover the cross-section of the mixing chamber.

[0008] Furthermore, the auxiliary material pipe has a third inlet at its top end and an outlet at its bottom end connected to the side wall of the mixing chamber, located close to the first inlet at the top of the mixing chamber; the axis of the outlet forms an angle with the jet direction of the fluid dispersion hole of the main material pipe, which can form a "convective impact" to promote the forced contact between the organic waste liquid and the oxygen.

[0009] Furthermore, the mixing chamber is made of 316L Hastelloy alloy, with an inner diameter of 100mm and a height of 2000mm.

[0010] Furthermore, the fluid dispersion holes have a diameter of 4 mm, with 4 holes per layer, and the fluid dispersion holes form a 30° angle with the axis of the main material pipe.

[0011] Furthermore, the inner diameter of the auxiliary material tube is 10mm.

[0012] Furthermore, it also includes high-pressure sealing flanges disposed on the first inlet and the guide port of the mixing chamber. The high-pressure sealing flanges realize the sealed connection between the first inlet and the upper cover of the supercritical water oxidation reactor and the guide port and the reaction inner cylinder of the supercritical water oxidation reactor. The specification of the high-pressure sealing flange is DN100, and the matching metal sealing gasket material is Inconel625.

[0013] Furthermore, the mixing chamber is also equipped with a temperature measurement interface and a sampling and detection port for installing thermocouples and sampling and detection.

[0014] To achieve the above objectives, the present invention also discloses a commissioning method for the feeding and mixing device described above, comprising the following steps:

[0015] Step S1, Pressure and sealing test: Connect the feeding mixing device to the upper cover of the reactor through the high-pressure sealing flange, and use a standard pressure source to conduct a pressure test on the mixing chamber at a pressure of 25 MPa for 30 minutes to confirm that there is no leakage;

[0016] Step S2, flow rate calibration: Zero point and range calibration are performed on the feed pump supplying the organic waste liquid and the flow meter supplying the oxygen. The rated flow rate of the organic waste liquid is set to 0-13.6L / h, and the rated flow rate of the oxygen is calibrated according to the theoretical amount of 1.3 times the oxygen-to-material ratio.

[0017] Step S3, Temperature Measurement and Sampling Calibration: Install the thermocouple at the temperature measurement interface of the mixing chamber, connect the online sampling device to the sampling detection port, calibrate the mixing uniformity detection method, and use gas chromatography to analyze the distribution of organic phase in the mixed material.

[0018] To achieve the above objectives, the present invention also discloses a feeding and mixing method for the feeding and mixing apparatus described above, comprising the following steps:

[0019] Step S1, Feed Start-up: Turn on the feed pump for the organic waste liquid and deliver a mixture of 90 vol.% tributyl phosphate and 10 vol.% kerosene at a flow rate of 13.6 L / h. At the same time, turn on the oxygen supply and introduce the oxygen at a flow rate of 8.5 m / h.

[0020] Step S2, Mixing Monitoring: The temperature inside the mixing chamber is monitored by the thermocouple. The temperature inside the mixing chamber is stable at 400-600℃ with no local overheating. The mixing uniformity is checked every 30 minutes through the sampling port, and the measured uniformity is ≥96%.

[0021] Step S3, Coordinated Control: When the quenching system of the supercritical water oxidation reactor adjusts the flow rate of the annular quenching water to 60 kg / h, the oxygen flow rate is simultaneously fine-tuned to ensure that the temperature fluctuation of the mixed material entering the reaction zone is ≤ ±8℃.

[0022] Step S4, Safety Control: If the pressure in the mixing chamber exceeds 26.25 MPa, the emergency relief valve of the reactor is triggered to open, and the overpressured material in the mixing chamber is discharged into the receiving tank.

[0023] The beneficial effects of this invention are as follows:

[0024] The supercritical water oxidation reactor feeding and mixing device provided by this invention, through the synergistic design of "three-dimensional dispersion + convection impact", is particularly suitable for the treatment of organic waste containing radioactive elements. It is used to rapidly mix the reactants during feeding, solving the core problem of insufficient mixing in existing feeding systems. It has high mixing efficiency, complete reaction, and completely avoids secondary pollution caused by insufficient mixing. It has strong adaptability and reliable operation. It is intelligent and controllable, and easy to operate: no additional manual intervention is required, and it meets the stringent automation requirements for radioactive waste liquid treatment. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the feeding and mixing device described in a specific embodiment of the present invention;

[0026] In the diagram: 1-mixing chamber, 2-first inlet, 3-guide port, 4-main material pipe, 5-fluid dispersion hole, 6-auxiliary material pipe, 7-second inlet. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] The present invention provides a feeding and mixing device (see Figure 1 The device, located between the upper cover and the inner cylinder of the supercritical water oxidation reactor, forms a continuous channel for "feeding-mixing-entry into the reaction zone." It includes a mixing chamber 1, a main material pipe 4 within the mixing chamber 1, and an auxiliary material pipe 6 connected to the mixing chamber 1. The organic waste liquid transported by the main material pipe 4 and the oxygen transported by the auxiliary material pipe 6 are efficiently and thoroughly mixed in the mixing chamber 1 before entering the reaction zone within the inner cylinder. The device is cylindrical in shape, with its axis coinciding with the vertical axis of the supercritical water oxidation reactor. The top of the device is fixed to the upper cover of the reactor via a sealing connection assembly, and the bottom is sealed to the top inlet of the inner cylinder, forming a high-pressure sealed cavity to prevent material leakage.

[0029] The mixing chamber 1 is a cylindrical structure with a smooth inner surface, serving as the core space for material mixing. A first inlet 2 is located at the top of the mixing chamber 1, which is connected to the main material inlet of the upper cover of the reactor. A guide port 3 is located at the bottom of the mixing chamber 1. The guide port 3 is a gradually narrowing guide port, which guides the mixed material to smoothly enter the inner cylinder of the reactor, avoiding impact on the fluid in the reaction zone.

[0030] The main material pipe 4 has a straight cylindrical structure and is coaxial with the mixing chamber 1. It has a second inlet at the top and a sealed structure at the bottom that is close to the guide port 3 of the mixing chamber 1. Several fluid dispersion holes 5 are provided on the side wall near the bottom of the main material pipe 4 to form a porous dispersion nozzle. The organic waste liquid is input from the second inlet at the top of the main material pipe 4 and output to the mixing chamber 1 through the fluid dispersion holes 5.

[0031] The fluid dispersion holes 5 are divided into several layers and distributed on different axial sections of the main material pipe 4. Each layer has several holes evenly arranged along the circumference of the main material pipe 4. Each fluid dispersion hole 5 is inclined downward at an angle to the axis of the main material pipe 4 (towards the bottom of the main material pipe 3), so that the organic waste liquid is dispersed into multiple oblique fine streams that cover the cross section of the mixing chamber 1. This "multi-angle porous structure" of the fluid dispersion holes 5 of the main material pipe 4 makes the organic waste liquid jet form a "three-dimensional dispersion", avoiding the material from agglomerating in the center of the mixing chamber 1.

[0032] The auxiliary material pipe 6 has a third inlet 7 at the top and an outlet at the bottom connected to the side wall of the mixing chamber 1, located near the first inlet 2 at the top of the mixing chamber 1; the axis of the outlet (orifice-shaped) is at an angle to the jet direction of the fluid dispersion hole 5 of the main material pipe 4, which can form a "convective impact" to promote forced contact between organic waste liquid and oxygen.

[0033] The mixing chamber 1 is made of 316L Hastelloy alloy, with an inner diameter of 100mm and a height of 2000mm.

[0034] The fluid dispersion holes 5 have a diameter of 4 mm, and 4 holes are set in each layer. The fluid dispersion holes 5 form a 30° angle with the axis of the main material pipe 4.

[0035] Auxiliary material pipe 6, inner diameter 10mm.

[0036] It also includes high-pressure sealing flanges installed on the first inlet 2 and the guide port 3 of the mixing chamber 1. The high-pressure sealing flanges achieve a sealed connection between the first inlet 2 and the upper cover of the supercritical water oxidation reactor, and between the guide port 3 and the reaction inner cylinder of the supercritical water oxidation reactor. The specification of the high-pressure sealing flange is DN100, and the matching metal sealing gasket material is Inconel625.

[0037] The mixing chamber 1 is also equipped with a temperature measuring interface and a sampling and detection port for installing thermocouples and sampling and detection.

[0038] A commissioning method for the feed mixing device as claimed in claim 10 includes the following steps:

[0039] Step S1, Pressure and sealing test: Connect the feeding mixing device to the upper cover of the reactor (the upper cover is also equipped with a flange that is compatible with the high pressure sealing flange) through the high pressure sealing flange. Use a standard pressure source to conduct a pressure test on mixing chamber 1, with a pressure of 25MPa and a pressure holding time of 30min, to confirm that there is no leakage.

[0040] Step S2, flow rate calibration: calibrate the zero point and range of the feed pump supplying the organic waste liquid and the flow meter supplying oxygen. Set the rated flow rate of the organic waste liquid to 0-13.6L / h and the rated flow rate of the oxygen to be calibrated according to the oxygen-to-material ratio of 1.3 times the theoretical amount (approximately 8.5m / h).

[0041] Step S3, Temperature Measurement and Sampling Calibration: Install a thermocouple (platinum-rhodium thermocouple) at the temperature measurement interface of mixing chamber 1, connect an online sampling device to the sampling detection port, calibrate the mixing uniformity detection method, and use gas chromatography to analyze the distribution of organic phase in the mixed material.

[0042] A feeding and mixing method for the feeding and mixing apparatus as claimed in claim 10 includes the following steps:

[0043] Step S1, Feed Start-up: Turn on the feed pump for organic waste liquid and deliver 90 vol.% tributyl phosphate + 10 vol.% kerosene mixture at a flow rate of 13.6 L / h. At the same time, turn on the oxygen supply and introduce oxygen at a flow rate of 8.5 m / h.

[0044] Step S2, Mixing Monitoring: The temperature inside mixing chamber 1 is monitored by thermocouples. The temperature inside mixing chamber 1 is stable at 400-600℃, with no local overheating. The mixing uniformity is checked every 30 minutes through the sampling port, and the measured uniformity is ≥96%.

[0045] Step S3, Coordinated Control: When the quenching system of the supercritical water oxidation reactor adjusts the annular quenching water flow rate to 60 kg / h, the oxygen flow rate is simultaneously fine-tuned (±0.2 m / h) to ensure that the temperature fluctuation of the mixed material entering the reaction zone is ≤±8℃.

[0046] Step S4, Safety Control: If the pressure in mixing chamber 1 exceeds 26.25 MPa, the emergency relief valve of the reactor will be triggered to open, and the overpressured material in mixing chamber 1 will be discharged into the receiving tank.

[0047] Runtime effect test

[0048] Mixing performance: The uniformity of mixing organic waste liquid with oxygen is 96.5%, and the decomposition rate of organic pollutants (tributyl phosphate) is 99.98%.

[0049] Reaction field stability: The maximum temperature in the reaction zone is 650℃, with a temperature fluctuation of ±8℃. The outer wall temperature of the inner reaction cylinder is 515℃ (lower than the design limit of 595℃).

[0050] The device described in this invention is not limited to the embodiments described in the specific implementation. Other implementation methods derived by those skilled in the art based on the technical solution of this invention also fall within the scope of technical innovation of this invention.

Claims

1. A feeding and mixing device, characterized in that: The supercritical water oxidation reactor is located between the upper cover and the inner cylinder of the reactor, including a mixing chamber (1), a main material pipe (4) located in the mixing chamber (1) and an auxiliary material pipe (6) connected to the mixing chamber (1). The organic waste liquid transported by the main material pipe (4) and the oxygen transported by the auxiliary material pipe (6) are fully mixed in the mixing chamber (1) and then enter the reaction zone in the inner cylinder of the reactor.

2. The feeding and mixing device as described in claim 1, characterized in that: The mixing chamber (1) is a cylindrical structure with a smooth inner surface; a first inlet (2) is provided at the top of the mixing chamber (1); a guide port (3) is provided at the bottom of the mixing chamber (1), and the guide port (3) is a tapered guide port to guide the mixed material smoothly into the inner cylinder of the reaction.

3. The feeding and mixing device as described in claim 2, characterized in that: The main material pipe (4) has a straight cylindrical structure and is coaxial with the mixing chamber (1). It has a second inlet at the top and a sealed structure at the bottom that is close to the guide port (3) of the mixing chamber (1). Several fluid dispersion holes (5) are provided on the side wall near the bottom of the main material pipe (4) to form a multi-hole dispersion nozzle. The organic waste liquid is input from the second inlet at the top of the main material pipe (4) and output to the mixing chamber (1) through the fluid dispersion holes (5).

4. The feeding and mixing device as described in claim 3, characterized in that: The fluid dispersion holes (5) are divided into several layers and distributed on different axial sections of the main material pipe (4). Each layer is uniformly arranged with several holes along the circumference of the main material pipe (4). Each fluid dispersion hole (5) is inclined downward at an angle to the axis of the main material pipe (4), so that the organic waste liquid is dispersed into multiple oblique fine streams that cover the cross section of the mixing chamber (1).

5. The feeding and mixing device as described in claim 4, characterized in that: The auxiliary material pipe (6) has a third inlet (7) at its top end and an outlet at its bottom end connected to the side wall of the mixing chamber (1), located close to the first inlet (2) at the top of the mixing chamber (1). The axis of the outlet is at an angle to the jet direction of the fluid dispersion hole (5) of the main material pipe (4), which can form a "convective impact" to promote the forced contact between the organic waste liquid and the oxygen.

6. The feeding and mixing device as described in claim 5, characterized in that: The mixing chamber (1) is made of 316L Hastelloy alloy, with an inner diameter of 100mm and a height of 2000mm.

7. The feeding and mixing device as described in claim 6, characterized in that: The fluid dispersion hole (5) has a diameter of 4 mm, and 4 holes are provided in each layer. The fluid dispersion hole (5) forms a 30° angle with the axis of the main material pipe (4).

8. The feeding and mixing device as described in claim 7, characterized in that: The auxiliary material pipe (6) has an inner diameter of 10 mm.

9. The feeding and mixing device as described in claim 8, characterized in that: It also includes high-pressure sealing flanges installed on the first inlet (2) and the guide port (3) of the mixing chamber (1). The high-pressure sealing flanges realize the sealing connection between the first inlet (2) and the upper cover of the supercritical water oxidation reactor and the guide port (3) and the reaction inner cylinder of the supercritical water oxidation reactor. The specification of the high-pressure sealing flange is DN100, and the matching metal sealing gasket material is Inconel 625.

10. The feeding and mixing device as described in claim 9, characterized in that: The mixing chamber (1) is also provided with a temperature measurement interface and a sampling and detection port for installing thermocouples and sampling and detection.

11. A commissioning method for the feeding and mixing device as described in claim 10, comprising the following steps: Step S1, pressure resistance and sealing test: Connect the feeding mixing device to the upper cover of the reactor through the high-pressure sealing flange, and use a standard pressure source to conduct a pressure resistance test on the mixing chamber (1) at a pressure of 25MPa for 30 minutes to confirm that there is no leakage; Step S2, flow rate calibration: The zero point and range of the feed pump supplying the organic waste liquid and the flow meter supplying the oxygen are calibrated. The rated flow rate of the organic waste liquid is set to 0-13.6L / h, and the rated flow rate of the oxygen is calibrated according to the theoretical amount of 1.3 times the oxygen-to-material ratio. Step S3, Temperature Measurement and Sampling Calibration: Install the thermocouple at the temperature measurement interface of the mixing chamber (1), connect the online sampling device to the sampling detection port, calibrate the mixing uniformity detection method, and use gas chromatography to analyze the distribution of organic phase in the mixed material.

12. A feeding and mixing method for the feeding and mixing apparatus as described in claim 10, comprising the following steps: Step S1, Feed Start-up: Turn on the feed pump for the organic waste liquid and deliver a mixture of 90 vol.% tributyl phosphate and 10 vol.% kerosene at a flow rate of 13.6 L / h. At the same time, turn on the oxygen supply and introduce the oxygen at a flow rate of 8.5 m / h. Step S2, Mixing monitoring: The temperature inside the mixing chamber (1) is monitored by the thermocouple. The temperature inside the mixing chamber (1) is stable at 400-600℃ with no local overheating. The mixing uniformity is checked every 30 minutes through the sampling port and the measured uniformity is ≥96%. Step S3, Coordinated Control: When the quenching system of the supercritical water oxidation reactor adjusts the flow rate of the annular quenching water to 60 kg / h, the oxygen flow rate is simultaneously fine-tuned to ensure that the temperature fluctuation of the mixed material entering the reaction zone is ≤ ±8℃. Step S4, Safety Control: If the pressure in the mixing chamber (1) exceeds 26.25 MPa, the emergency relief valve of the reactor is triggered to open and discharge the overpressure material in the mixing chamber (1) into the receiving tank.

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