CN107449860A - A kind of rotary high temp fused salt corrosion system for simulating feature - Google Patents

Abstract

The invention discloses a rotating high-temperature molten salt corrosion characteristic simulation system, belonging to the field of heat storage medium detection equipment for concentrated solar thermal power generation, including a molten salt tank, a stirring device, a motor, and a motor lifting device for controlling the lifting of the motor. There is also an electric heating device in the molten salt tank; one end of the stirring device is fixed on the bottom of the motor, and the other end extends into the molten salt tank. The stirring device can be driven by the motor to lift and rotate, and the stirring device extends into one end of the molten salt tank. Place the sample to be tested on it. The rotating high-temperature molten salt corrosion characteristic simulation system of the present invention can fully and effectively reflect the corrosion conditions of molten salt medium, flow rate, temperature, etc. on metal samples of different materials, and the system can operate continuously at high temperature for a long time (from 2000h) , so as to simulate the scene more realistically, and the analysis of the corrosion results of the samples to be tested is more convincing.

Description

A Rotary High Temperature Molten Salt Corrosion Characteristic Simulation System

technical field

The invention belongs to the field of thermal storage medium detection equipment for concentrating solar thermal power generation, and in particular relates to a rotating high-temperature molten salt corrosion characteristic simulation system.

Background technique

Energy occupies a very important position in the process of social development. With the continuous development of my country's economy, energy consumption is also increasing. Concentrating solar thermal power generation (CSP) is easy to integrate and thermal energy storage system (TES) is feasible. The reliability and high efficiency make CSP commercially more attractive than other renewable energy sources. Among CSP thermal storage media, molten salt mixtures are often used as heat transfer fluid (HTF) and thermal energy storage (TES) media due to their advantages such as high thermal conductivity, good thermal and chemical stability, and fast mass transfer rate. In-depth research on mixed nitrates abroad has proved that the composite binary molten salt composed of 60% NaNO ₃ and 40% KNO ₃ is very suitable for the use of concentrating solar high temperature thermal power generation.

For CSP power plants and molten salts, the corrosion behavior of materials is a problem that cannot be ignored. For this reason, relevant scholars at home and abroad have also carried out research on the corrosion of molten salts. In 1985, Slusser et al. studied and analyzed the corrosion behavior of nitrate and nitrite on nickel-based alloy steel in the CSP system. Later, some scholars conducted experimental research on stainless steel and other alloy steels.

In terms of experimental devices, there are many high-temperature molten salt device systems for static experiments, but the static experiments are quite different from the actual situation, and the coupling effect of multiple physical fields is difficult to reflect. In terms of operation mode, in the prior art, metal samples are generally placed directly or rely on the bottom of the crucible for high-temperature corrosion experiments. However, in such experimental results, the pattern corrosion is often very uneven, and the parts in contact with the crucible wall are more severely corroded, and it is precisely because of the contact that the crucible wall interferes with the metal pattern, so the corrosion results cannot really reflect the effect of the corrosive medium on the metal pattern. Corrosion condition. In the existing dynamic molten salt corrosion system device, there are molten salt heat storage tank and pipeline system. The molten salt flows in the pipeline and circulates in the whole system, which is easy to condense and block the pipeline. Also more demanding.

Contents of the invention

In order to overcome the above-mentioned defects in the prior art, the object of the present invention is to provide a rotating high-temperature molten salt corrosion characteristic simulation system, which has a reasonable structure design, simple operation, and comprehensive and effective test results.

The present invention is achieved through the following technical solutions:

A rotary high-temperature molten salt corrosion characteristic simulation system disclosed in the present invention includes a molten salt tank, a stirring device, a motor, and a motor lifting device for controlling the lifting of the motor. The molten salt tank is also equipped with an electric heating device; the stirring device One end is fixed at the bottom of the motor, and the other end extends into the molten salt tank. The motor can drive the stirring device to lift and rotate, and the end of the stirring device extending into the molten salt tank is placed with a sample to be tested.

Preferably, the motor lifting device includes a motor base disc, a top fixing frame, a top turntable, a rotating shaft and several brackets, one end of the bracket is detachably arranged on the top fixing frame, and the other end is fixedly arranged on the top wall of the molten salt tank; the rotating shaft The axis passing through the top fixed frame and the top turntable goes straight to the inside of the molten salt tank, and the top turntable is movably connected above the top fixed frame;

The motor is set on the rotating shaft, and the motor slides up and down along the rotating shaft by turning the top turntable; the motor base disc is set at the top opening of the molten salt tank, and when the motor falls to the bottom end, it snaps onto the motor base disc.

Preferably, the stirring device includes a stirring shaft. The upper end of the stirring shaft is connected to the bottom of the motor, and the lower end of the stirring shaft extends into the molten salt tank, and a plurality of stirring rods are arranged at the lower end, and a plurality of samples to be tested are arranged on the stirring rods.

Preferably, the sample to be tested has a T-shaped structure, and a plurality of jacks for inserting the sample to be tested are provided on the stirring rod.

Preferably, there are 4 stirring rods, and the 4 stirring rods are arranged crosswise.

Preferably, it also includes a thermocouple sleeve arranged in the tank body of the molten salt tank, a number of round holes corresponding to the positions of the jacks on the stirring rod are opened at the bottom of the thermocouple sleeve, and holes for real-time Thermocouple wire to measure the temperature of the sample to be tested.

Preferably, the thermocouple well is a Z-type well.

Preferably, the electric heating device includes several heating coils and resistance wires arranged in the bottom and side wall of the molten salt tank, and the electric heating device can raise the temperature of the tank body of the molten salt tank to 550°C.

Preferably, a temperature control device for monitoring temperature is also provided in the molten salt tank.

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

The rotary high-temperature molten salt corrosion characteristic simulation system disclosed by the present invention includes a molten salt tank with an electric heating device inside, a motor and a motor lifting device capable of controlling the lifting of the motor, and a bottom of the motor that can extend into the molten salt Stirring device inside the tank, the samples to be tested are all placed on the stirring device. When conducting high-temperature corrosion experiments, the rotation of the motor drives the stirring device to rotate, and the height of the motor is adjustable, so that the depth of the stirring device extending into the molten salt tank can be adjusted, and the electric heating device inside the molten salt tank can provide different The temperature changes, so that the sample to be tested is static or rotated and immersed in the molten salt medium to complete different test requirements. The rotating high-temperature molten salt corrosion characteristic simulation system of the present invention can fully and effectively reflect the corrosion conditions of molten salt medium, flow rate, temperature, etc. on metal samples of different materials, and the system can operate continuously at high temperature for a long time (from 2000h) , so as to simulate the scene more realistically, and the analysis of the corrosion results of the samples to be tested is more convincing.

Further, a motor base disc and a bearing are provided at the contact position between the motor and the molten salt tank (that is, at the top opening of the molten salt tank), and when the motor is lowered to the lowest position, it can be engaged with the motor base disc so that the motor goes straight up. Directly reduce the eccentric movement error, so that the stirring device will not touch the tube wall, thus making the experimental system safer.

Further, the motor lifting device includes a top fixed frame, a top turntable, a rotating shaft and several supports, one end of which is detachably arranged on the top fixed frame, and the other end is fixedly arranged on the top wall of the molten salt tank; the motor is arranged on the rotating shaft, Turn the top turntable to make the motor slide up and down along the rotating shaft to complete the lifting.

Further, the stirring rod is provided with a plurality of jacks for inserting the sample to be tested, and the shape of the jack is adjusted according to the size of the sample to be tested to ensure that the sample to be tested will not fall when inserted into the jack , the sockets at different positions have the same angular velocity but different linear velocities, so that multiple fluid stable velocities under the same working condition can be obtained.

Further, there are 4 stirring rods, and the 4 stirring rods are arranged crosswise, and different material samples to be tested can be inserted on the 4 stirring rods, and corrosion experiments of different materials under the same conditions can be carried out at the same time. At the same time, the sample to be tested on the stirring rod can be taken out or placed in any hanging position at any time to meet different experimental needs.

Further, the electric heating device includes a plurality of thermocouple bushing holes arranged inside the molten salt tank, and thermocouple bushings are arranged in the thermocouple bushing holes for measuring different positions on the same horizontal plane inside the molten salt tank, and Temperature of molten salt at different heights.

Furthermore, a temperature control device is also installed in the molten salt tank to monitor the temperature in real time and keep the temperature constant.

Description of drawings

Fig. 1 is a structural schematic diagram of a rotary high-temperature molten salt corrosion characteristic simulation system disclosed by the present invention;

Fig. 2 is a structural cross-sectional view of the rotating high-temperature molten salt corrosion characteristic simulation system disclosed by the present invention;

Fig. 3 is a schematic structural diagram of a thermocouple sleeve of the rotary high-temperature molten salt corrosion characteristic simulation system disclosed in the present invention.

Among them, 1 is the molten salt tank; 2 is the stirring device; 3 is the motor base disc; 4 is the motor; 5 is the top fixing frame; 6 is the stirring shaft; Rod; 10 is the top rotating disk; 11 is the rotating shaft.

detailed description

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

Referring to Fig. 1, a rotary high temperature molten salt corrosion characteristic simulation system disclosed by the present invention includes a molten salt tank 1, a stirring device 2, a motor 4 and a motor lifting device for controlling the lifting of the motor 4, and the molten salt tank 1 is also Equipped with an electric heating device; one end of the stirring device 2 is fixed on the bottom of the motor 4, and the other end extends into the molten salt tank 1, the stirring device 2 can be driven by the motor 4 to lift and rotate, and the stirring device 2 extends into the molten salt tank 1 Place the sample 8 to be tested on one end. During the test, the molten salt tank 1 is filled with molten salt as a heat storage medium with a composition of 60% NaNO3 and 40% _{KNO3 ;}

The motor lifting device includes a motor base disc 3, a top fixing frame 5, a top turntable 10, a rotating shaft 11 and several supports. One end of the support is detachably arranged on the top fixing frame 5, and the other end is fixedly arranged on the top wall of the molten salt tank 1. top; the rotating shaft 11 passes through the top fixing frame 5 and the shaft center of the top rotating disk 10 and goes straight to the inside of the molten salt tank 1, and the top rotating disk 10 is flexibly connected above the top fixing frame 5; the motor 4 is arranged on the rotating shaft 11, and by rotating the top rotating disk 10, The motor 4 slides up and down along the rotating shaft 11; the motor base disc 3 is arranged at the top opening of the molten salt tank 1, and the motor 4 base is engaged with the motor base disc 3 when it falls to the bottom end.

Referring to Fig. 2, the stirring device 2 comprises a stirring shaft 6, the stirring shaft 6 upper end is connected with the bottom of the motor 4, the lower end extends into the molten salt tank 1, and a plurality of stirring rods 9 are arranged at the lower end, and a number of stirring rods 9 are arranged on the stirring rod 9. Test sample 8.

Preferably, the test sample 8 has a T-shaped structure, and a plurality of jacks for inserting the test sample 8 are provided on the stirring rod 9 . The shape of the jack is adjusted according to the size of the sample to be tested to ensure that the sample to be tested will not fall when inserted into the jack. The jacks at different positions have the same angular velocity but different linear velocities, so that the same working condition can be obtained. Down multiple fluid steady speeds. The stirring rod 9 rotates stably and at a constant speed under the constant power of the motor 4, and the corrosion conditions of the test sample 8 at different linear speeds at the same angular speed can be obtained.

Preferably, there are 4 stirring rods 9, and the 4 stirring rods 9 are arranged crosswise. The test samples of different materials can be inserted on the 4 stirring rods, and the corrosion experiments of different materials under the same conditions can be carried out at the same time. At the same time, the sample to be tested on the stirring rod can be taken out or placed in any hanging position at any time to meet different experimental needs.

Preferably, the electric heating device includes several heating coils and resistance wires arranged in the bottom and side walls of the molten salt tank 1, and the electric heating device can raise the tank temperature of the molten salt tank 1 to 550°C.

Referring to FIG. 3 , a thermocouple sleeve 7 is also provided inside the tank body of the molten salt tank 1 , and four small round holes are provided at the bottom side of the thermocouple sleeve 7 corresponding to the insertion hole of the stirring rod 9 . Embed 4 thermocouple wires in the holes of the thermocouple casing, and protrude from the 4 small round holes on the bottom side of the thermocouple casing 7, so that the real-time temperature of each test piece 8 can be evenly measured . A temperature control device for monitoring temperature is also provided in the molten salt tank 1 .

The rotary high-temperature molten salt corrosion characteristic simulation system of the present invention (taking 4 stirring rods 9 as an example), when in use, the test process is as follows:

1. Debugging and running. Check whether the various subsystems such as motor 4 frequency conversion speed regulation, power supply setting, electric heating device and constant temperature automatic control are working normally, whether the grounding wire is connected, whether the periphery of the molten salt tank is in a safe state, raise the motor 4 and suspend it in the air, and place the 16 Each sample piece 8 to be tested is suspended on four stirring rods 9 respectively.

2. Filling and heating. Slowly and carefully pour molten salt with a good ratio (60% NaNO ₃ and 40% KNO ₃ ) into the molten salt tank 1, the filling height is about half of the molten salt tank body, and then turn on the electric heating device to raise the temperature. When the temperature reaches 290°C, the molten salt becomes liquid, and at this time, about a quarter of the solid molten salt is added. This cycle stops when the amount of molten salt meets the test conditions. At the same time, the molten salt temperature rose to the working condition required for the experiment.

3. Conduct experiments. Rotate the top turntable 10, drop it to a suitable position, start the motor 4, drive the stirring shaft 6 to rotate, the sample to be tested 8 is corroded in the flowing molten salt, after reaching a certain working time, turn off the motor 4, and take out the thermocouple sleeve 7 , and record the data. Then take out the sample piece 8 to be tested. The duration of each working condition is about 10 days. During this period, the motor should be kept running and the temperature should be kept constant.

4. Pick up the test piece. The first installation of the test piece is before the experiment begins. After completing a set of working conditions, turn off the motor 4, rotate the top turntable 10 to make the motor 4 slide upward to a suitable position, at this time, use the test hook to take out the sample to be tested, then reset the motor 4, and wait for the test sample to cool to room temperature Finally, wash the molten salt and loose corrosion substances adhering to the test piece in acetone solution. After cleaning, dry it in an oven, weigh it with an electronic balance after cooling and record the weight after corrosion.

5. Data collection and recording. Due to the long experiment period, only a period of time is needed for data collection each time. Repeat the above steps to complete the experiment.

In summary, the rotary high-temperature molten salt corrosion characteristic simulation system disclosed in the present invention includes a molten salt tank, an electric heating device, a motor lifting device, and a stirring device. The motor can move straight up and down, and the eccentricity error is small. A flexible T-shaped sample to be tested is inserted into the stirring rod connected to the stirring shaft, and the sample to be tested is inserted directly into the jack without falling or shaking. When carrying out the high temperature corrosion test, the static or rotating sample to be tested is immersed in the molten salt medium of 60% NaNO ₃ and 40% KNO ₃ . The rotating high-temperature molten salt corrosion characteristic simulation system of the present invention can comprehensively and effectively reflect the corrosion conditions of molten salt medium, flow rate, temperature, etc. on metal samples of different materials.

Claims (9)

1. a kind of rotary high temp fused salt corrosion system for simulating feature, it is characterised in that including fused salt tank (1), agitating device (2), motor (4) and the motor lowering or hoisting gear for controlled motor (4) lifting, fused salt tank (1) is interior to be additionally provided with electric heater unit； Motor (4) bottom is fixed in one end of agitating device (2), and the other end is stretched into fused salt tank (1), and motor (4) can drive stirring Device (2) is lifted and rotated, and print to be tested (8) is placed with one end that agitating device (2) is stretched into fused salt tank (1).

2. rotary high temp fused salt corrosion system for simulating feature according to claim 1, it is characterised in that motor lifting dress Put including motor base disk (3), top fixed mount (5), top rotatable disc (10), rotating shaft (11) and some supports, the one of support End is dismountable to be arranged on top fixed mount (5), and the other end is fixedly installed on fused salt tank (1) roof；Rotating shaft (11) passes through The axle center of top fixed mount (5) and top rotatable disc (10) leads directly to fused salt tank (1) inside, and top rotatable disc (10) is movably connected in top Above fixed mount (5)；

Motor (4) is arranged in rotating shaft (11), motor (4) is prolonged rotating shaft (11) by rotating top rotatable disc (10) and is slided up and down； Motor base disk (3) is arranged at fused salt tank (1) top open part, and motor (4) is sticked in motor base circle when being down to lowermost end On disk (3).

3. rotary high temp fused salt corrosion system for simulating feature according to claim 1, it is characterised in that agitating device (2) agitating shaft (6) is included, agitating shaft (6) upper end is connected with motor (4) bottom, and lower end is stretched into fused salt tank (1), and in lower end Provided with some stirring rod (9), stirring rod (9) is provided with some prints (8) to be tested.

4. rotary high temp fused salt corrosion system for simulating feature according to claim 3, it is characterised in that print to be tested (8) it is T-type structure, multiple jacks for being used to insert the print to be tested (8) is provided with stirring rod (9).

5. the rotary high temp fused salt corrosion system for simulating feature according to claim 3 or 4, it is characterised in that stirring rod (9) it is 4,4 stirring rod (9) are arranged in a crossed manner.

6. rotary high temp fused salt corrosion system for simulating feature according to claim 4, it is characterised in that also include setting A thermocouple sheath (7) in fused salt tank (1) tank body, some and stirring rod is offered in thermocouple sheath (7) bottom (9) circular hole corresponding to the jack position on, the thermocouple for measuring print to be tested (8) temperature in real time is equipped with circular hole Silk.

7. rotary high temp fused salt corrosion system for simulating feature according to claim 6, it is characterised in that thermocouple sheath (7) it is Z-type sleeve pipe.

8. rotary high temp fused salt corrosion system for simulating feature according to claim 1, it is characterised in that electric heater unit Including some heating coils and resistance wire being arranged in fused salt tank (1) tank base and side wall, electric heater unit will can melt The pot temperature of salt cellar (1) rises to 550 DEG C.

9. rotary high temp fused salt corrosion system for simulating feature according to claim 1, it is characterised in that fused salt tank (1) Inside it is additionally provided with the temperature control device for monitoring temperature.