A method for precisely and automatically regulating the water vapor and oxygen content in a heat treatment process

Abstract

The present invention discloses a method for precisely and automatically regulating the water vapor and oxygen content in a heat treatment process, which comprises the following steps: using oxygen as a carrier gas to introduce water vapor into a heat treatment device; at the inlet end of the heat treatment device, measuring the proportion of water vapor and the oxygen content in the mixed gas that can reach the surface of the material to be treated in the heat treatment device; based on the proportion of water vapor and the oxygen content in the mixed gas, controlling the inlet speeds of oxygen and water vapor, so as to achieve precise and automatic regulation of the proportion of water vapor and the oxygen content in the process. The present invention is applied to the field of materials engineering technology, solves the problems of inaccurate control of the proportion of water vapor and the oxygen content and complex adjustment process during the heat treatment of composite materials in a high-temperature water-oxygen mixed atmosphere, and provides a method support for the preparation of a precisely and automatically controlled water-oxygen mixed heat treatment device.

Description

Technical Field

[0001] The present invention relates to the technical field of materials engineering, and particularly to a method for precisely regulating the proportion of water vapor and oxygen content in the heat treatment process of a material in a water-oxygen mixed atmosphere. Background Art

[0002] Proceeding from the actual application of SiC fiber-reinforced ceramic matrix composites in aeroengines, it is necessary to place the materials in a simulated combustion working environment of an aeroengine (water vapor content 5-10%) for experiments in order to accumulate scientific research data and practical experience. To study the influence mechanism of water vapor on the oxidation behavior of composites, it is necessary to carry out oxidation research on composites in a water-oxygen atmosphere.

[0003] Northwestern Polytechnical University is the earliest domestic unit to carry out oxidation research on composites in a water-oxygen environment. Its water-oxygen experimental equipment is all self-built. By using the difference in the saturated vapor pressure of water at different temperatures and using carrier gases such as argon and oxygen to introduce water vapor in different proportions into the reaction furnace, research on the performance and mechanism of C f / SiC and SiC f / SiC composites in a water-oxygen mixed atmosphere has been carried out. National University of Defense Technology has also built similar equipment using this method and carried out oxidation research on SiC fibers in a water-oxygen environment using it. Such equipment has wide universality and is convenient to assemble, but it has the disadvantages that the vapor pressure is greatly affected by temperature, water vapor is easy to condense in the pipeline, and the water vapor atmosphere cannot be measured.

[0004] In the actual operation process, the proportion of water vapor may also be affected by factors such as atmospheric pressure, humidity, type of carrier gas, and carrier gas flow rate. Hay et al. abroad used a peristaltic pump to inject water into a tube furnace, which was heated to form water vapor to react with the fibers. The water vapor content was controlled by the flow rate of the peristaltic pump, which better solved the problem of control accuracy and there was no condensation phenomenon. However, such equipment can only perform pure water vapor oxidation experiments and it is difficult to introduce other carrier gases, which will cause the water vapor to not flow effectively and cannot meet the requirements of diverse experiments.

[0005] In summary, in order to scientifically carry out high-temperature water-oxygen heat treatment experiments on composites, there is an urgent need for a method for precisely regulating the proportion of water vapor and oxygen content in the heat treatment process of a material in a water-oxygen mixed atmosphere. Summary of the Invention

[0006] Aiming at the deficiencies in the prior art that the control of the proportion of water vapor and oxygen content is inaccurate and the adjustment process is complex when composites are heat-treated in a high-temperature water-oxygen mixed atmosphere, the present invention provides a method for precisely and automatically regulating the water vapor and oxygen content in the heat treatment process, providing a method support for the preparation of a precise and automatic water-oxygen mixed heat treatment device.

[0007] To achieve the above object, the present invention provides a method for precisely and automatically regulating the water vapor and oxygen content in a heat treatment process, comprising the following steps:

[0008] Step 1: Using oxygen as a carrier gas, introduce water vapor into the heat treatment equipment.

[0009] Step 2: At the inlet end of the heat treatment equipment, measure the proportion of water vapor and the oxygen content in the mixed gas that can reach the surface of the material to be treated in the heat treatment equipment.

[0010] Step 3: Based on the proportion of water vapor and the oxygen content in the mixed gas, control the inlet speeds of oxygen and water vapor, thereby achieving precise and automatic regulation of the proportion of water vapor and the oxygen content in the process.

[0011] In one embodiment, in Step 1, the process of generating and controlling the proportion of water vapor is as follows:

[0012] Pump water into the water vapor generator through a piston pump, and convert the water into water vapor through the water vapor generator, which serves as the gas source of the water vapor in Step 1.

[0013] Among them, the proportion of water vapor in the mixed gas is regulated by controlling the liquid inlet speed of the piston pump.

[0014] In one embodiment, in Step 1, the process of generating and controlling the oxygen content is as follows:

[0015] Use a high-purity oxygen storage tank as the gas source of the oxygen in Step 1.

[0016] Install a mass flowmeter on the pipeline between the high-purity oxygen storage tank and the water vapor generator, and regulate the oxygen content in the mixed gas by controlling the inlet speed of the mass flowmeter.

[0017] In one embodiment, in Step 2, the proportion of water vapor and the oxygen content in the mixed gas are measured by installing an oxygen content analyzer and a water vapor analyzer at the inlet end of the heat treatment equipment.

[0018] In one embodiment, in Step 3, the control of the inlet speeds of oxygen and water vapor specifically includes:

[0019] Feed the real-time proportion of water vapor and the real-time oxygen content in the mixed gas back to the industrial control computer.

[0020] The industrial control computer generates a control signal based on the difference between the real-time proportion of water vapor and the actual required proportion of water vapor, and / or the difference between the real-time oxygen content and the actual required oxygen content.

[0021] Adjust the liquid inlet speed of the piston pump and / or the inlet speed of the mass flowmeter through the control signal.

[0022] In one embodiment, when the difference between the real-time water vapor ratio and the actual required water vapor ratio is positive, the control signal adjusts the liquid inlet speed of the plunger pump to decrease;

[0023] When the difference between the real-time water vapor ratio and the actual required water vapor ratio is negative, the control signal adjusts the liquid inlet speed of the plunger pump to increase.

[0024] In one embodiment, when the difference between the real-time oxygen content and the actual required oxygen content is positive, the control signal adjusts the air inlet speed of the mass flowmeter to decrease;

[0025] When the difference between the real-time oxygen content and the actual required oxygen content is negative, the control signal adjusts the air inlet speed of the mass flowmeter to increase.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects:

[0027] 1. The method provided by the present invention can accurately control the water vapor ratio and the oxygen content:

[0028] The existing methods generally use a constant temperature water tank as the gas source of water vapor, and use the change of saturated vapor pressure at different temperatures as the control method of the water vapor ratio. A rotameter is used to control the oxygen flow rate; the control precision of the water vapor ratio and the oxygen content is low, and the flow rate is unstable. The method provided by the present invention uses a combination of a plunger pump and a water vapor generator as the gas source of water vapor. The plunger pump pumps distilled water into the water vapor generator to completely vaporize the distilled water, thereby obtaining water vapor, and the water vapor content is precisely controllable. A mass flowmeter is used to control the oxygen flow rate, and the control precision is better than that of the rotameter, and the flow rate is more stable;

[0029] 2. The method provided by the present invention can accurately measure the water vapor ratio and the oxygen content:

[0030] The existing methods generally do not use or rarely use methods to measure the water vapor ratio and the oxygen content, which makes the water and oxygen content reaching the surface of the heat-treated material unknown, which is not conducive to scientific research. The present invention sets a water vapor analyzer and an oxygen content analyzer at the air inlet end of the heat treatment equipment, and can accurately measure the water and oxygen ratio reaching the surface of the heat-treated material;

[0031] 3. The method provided by the present invention can automatically adjust the water vapor ratio and the oxygen content:

[0032] Existing methods cannot automatically adjust the proportion of water vapor and oxygen content. Through the control software installed in the industrial control computer, the present invention can receive the measurement results of the water vapor analyzer and the oxygen content analyzer, and automatically adjust the flow rate of the mass flow meter and the liquid inlet speed of the plunger pump according to the difference between the measurement results and the set values until the measured value is exactly the same as the set value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0034] Figure 1 It is a schematic diagram for realizing the method for precisely and automatically regulating the water vapor and oxygen content in the heat treatment process in the embodiment of the present invention.

[0035] The realization of the object of the present invention, its functional features and advantages will be further described in conjunction with the embodiments and with reference to the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0037] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0038] This embodiment discloses a method for precisely and automatically regulating the water vapor and oxygen content in the heat treatment process, which is realized through Figure 1 the system shown. The system includes a high-purity oxygen storage tank, an oxygen pressure reducing valve, a mass flow meter, a plunger pump, a water vapor generator, a stop valve, a heat treatment device, an oxygen analyzer, a water vapor analyzer, and an industrial control computer. Specifically:

[0039] The oxygen pressure reducing valve is arranged at the tank opening of the high-purity oxygen storage tank and is used for reducing the pressure of the oxygen in the high-purity oxygen storage tank;

[0040] The high-purity oxygen storage tank is connected to the steam generator through the first pipeline, and a mass flowmeter is arranged on the first pipeline to control the oxygen flow rate entering the steam generator;

[0041] The plunger pump is connected to the steam generator through a pipeline and is used to pump water into the steam generator to generate steam;

[0042] The steam is connected to the heat treatment equipment through the second pipeline, and a stop valve, an oxygen analyzer, and a steam analyzer are all arranged on the second pipeline;

[0043] The industrial control computer is respectively communicatively controlled and connected to the oxygen analyzer, the steam analyzer, the mass flowmeter, and the plunger pump.

[0044] Based on Figure 1 the system shown, the method for precisely and automatically regulating the steam and oxygen content in the heat treatment process in this embodiment specifically includes the following steps:

[0045] Step 1, using oxygen as the carrier gas to bring steam into the heat treatment equipment. The specific implementation process is as follows:

[0046] Pump water into the steam generator through the plunger pump, and convert the water into steam through the steam generator, which is used as the steam source in Step 1. Among them, the steam generation amount can be calculated according to the liquid inlet amount of the plunger pump. Therefore, the steam ratio in the mixed gas can be regulated by controlling the liquid inlet speed of the plunger pump. The accuracy of the steam ratio depends on the accuracy of the plunger pump. The stable performance of the plunger pump adopted in this embodiment effectively ensures the high accuracy of the steam ratio.

[0047] Use the high-purity oxygen storage tank as the oxygen source in Step 1. Connect the high-purity oxygen storage tank and the steam generator through a pipeline, and use oxygen as the carrier gas to bring steam into the heat treatment equipment for water-oxygen mixed atmosphere heat treatment of materials. A mass flowmeter is arranged on the pipeline between the high-purity oxygen storage tank and the steam generator, and the oxygen content in the mixed gas is regulated by controlling the intake speed of the mass flowmeter. The accuracy of the oxygen content depends on the mass flowmeter. The accuracy of the mass flowmeter adopted in this embodiment can effectively ensure the high accuracy of the oxygen content.

[0048] Step 2, at the intake end of the heat treatment equipment, measure the steam ratio and oxygen content in the mixed gas that can reach the surface of the material to be treated in the heat treatment equipment. The specific implementation process is as follows:

[0049] Set an oxygen content analyzer and a steam analyzer at the intake end of the heat treatment equipment to accurately measure the steam ratio and oxygen content that can reach the surface of the material to be treated.

[0050] Step 3, based on the water vapor ratio and oxygen content in the mixed gas, control the inlet speeds of oxygen and water vapor, so as to achieve precise automatic regulation of the water vapor ratio and oxygen content in the process. The specific implementation process is as follows:

[0051] Feed back the real-time water vapor ratio and real-time oxygen content in the mixed gas to the industrial control computer;

[0052] The industrial control computer generates a control signal according to the difference between the real-time water vapor ratio and the actual required water vapor ratio, and / or the difference between the real-time oxygen content and the actual required oxygen content;

[0053] Adjust the liquid inlet speed of the plunger pump and / or the gas inlet speed of the mass flowmeter through the control signal. The specific regulation methods are as follows:

[0054] When the difference between the real-time water vapor ratio and the actual required water vapor ratio is positive, the control signal adjusts the liquid inlet speed of the plunger pump to decrease;

[0055] When the difference between the real-time water vapor ratio and the actual required water vapor ratio is negative, the control signal adjusts the liquid inlet speed of the plunger pump to increase;

[0056] When the difference between the real-time oxygen content and the actual required oxygen content is positive, the control signal adjusts the gas inlet speed of the mass flowmeter to decrease;

[0057] When the difference between the real-time oxygen content and the actual required oxygen content is negative, the control signal adjusts the gas inlet speed of the mass flowmeter to increase.

[0058] The following further illustrates the method for precisely and automatically regulating the water vapor and oxygen content in the heat treatment process in this embodiment with specific examples.

[0059] Example 1

[0060] To obtain a mixed atmosphere containing 50.00 vol% water vapor and 50.00 vol% oxygen, set the oxygen inlet speed to 10 ml / min, the theoretical water vapor flow rate to 10 ml / min, then the theoretical liquid inlet volume of distilled water is 8.04 μl / min. When actually operating with these parameters, the oxygen content measured by the oxygen analyzer is 51.05%, and the water vapor content is 49.35%. After automatic regulation using this method, the measured value by the oxygen analyzer is 50.00%, and the water vapor content is 50.00%. At this time, the actual oxygen inlet speed is 9.90 ml / min, and the actual liquid inlet volume of distilled water is 8.12 μl / min.

[0061] Example 2

[0062] To obtain a mixed atmosphere containing 50.00 vol% water vapor and 50.00 vol% oxygen, the oxygen inlet velocity was set at 20 ml / min and the theoretical water vapor flow rate was 20 ml / min. Then, the theoretical liquid feed rate of distilled water was 16.07 μl / min. When actually operating with these parameters, the oxygen content measured by the oxygen analyzer was 50.96% and the water vapor content was 48.84%. After automatic regulation using this method, the measured value by the oxygen analyzer was 50.00% and the water vapor content was 50.00%. At this time, the actual oxygen inlet velocity was 19.96 ml / min and the actual liquid feed rate of distilled water was 16.15 μl / min.

[0063] Example 3

[0064] To obtain a mixed atmosphere containing 10.00 vol% water vapor and 90.00 vol% oxygen, the oxygen inlet velocity was set at 45 ml / min and the theoretical water vapor flow rate was 5 ml / min. Then, the theoretical liquid feed rate of distilled water was 4.02 μl / min. When actually operating with these parameters, the oxygen content measured by the oxygen analyzer was 91.81% and the water vapor content was 9.35%. After automatic regulation using this method, the measured value by the oxygen analyzer was 90.00% and the water vapor content was 10.00%. At this time, the actual oxygen inlet velocity was 44.43 ml / min and the actual liquid feed rate of distilled water was 4.24 μl / min.

[0065] Example 4

[0066] To obtain a mixed atmosphere containing 20.00 vol% water vapor and 80.00 vol% oxygen, the oxygen inlet velocity was set at 20 ml / min and the theoretical water vapor flow rate was 5 ml / min. Then, the theoretical liquid feed rate of distilled water was 4.02 μl / min. When actually operating with these parameters, the oxygen content measured by the oxygen analyzer was 81.66% and the water vapor content was 18.52%. After automatic regulation using this method, the measured value by the oxygen analyzer was 80.00% and the water vapor content was 20.00%. At this time, the actual oxygen inlet velocity was 19.52 ml / min and the actual liquid feed rate of distilled water was 4.18 μl / min.

[0067] Example 5

[0068] To obtain a mixed atmosphere containing 30.00 vol% water vapor and 70.00 vol% oxygen, the oxygen inlet velocity was set at 21 ml / min, and the theoretical water vapor flow rate was 9 ml / min. Then, the theoretical liquid feed rate of distilled water was 7.23 μl / min. When actually operating with these parameters, the oxygen content measured by the oxygen analyzer was 71.09%, and the water vapor content was 28.77%. After automatic regulation using this method, the measured value by the oxygen analyzer was 70.00%, and the water vapor content was 30.00%. At this time, the actual oxygen inlet velocity was 20.73 ml / min, and the actual liquid feed rate of distilled water was 7.61 μl / min.

[0069] Example 6

[0070] To obtain a mixed atmosphere containing 40.00 vol% water vapor and 60.00 vol% oxygen, the oxygen inlet velocity was set at 30 ml / min, and the theoretical water vapor flow rate was 20 ml / min. Then, the theoretical liquid feed rate of distilled water was 16.07 μl / min. When actually operating with these parameters, the oxygen content measured by the oxygen analyzer was 60.24%, and the water vapor content was 39.23%. After automatic regulation using this method, the measured value by the oxygen analyzer was 60.00%, and the water vapor content was 40.00%. At this time, the actual oxygen inlet velocity was 29.88 ml / min, and the actual liquid feed rate of distilled water was 16.18 μl / min.

[0071] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made using the description and drawings of the present invention under the inventive concept of the present invention, or any direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A method for precisely and automatically regulating the water vapor and oxygen content in a heat treatment process, characterized in that, It includes the following steps: Step 1: Take water vapor into the heat treatment equipment with oxygen as the carrier gas; Step 2: At the intake end of the heat treatment equipment, measure the proportion of water vapor and the oxygen content in the mixed gas that can reach the surface of the material to be treated in the heat treatment equipment; Step 3: Based on the proportion of water vapor and the oxygen content in the mixed gas, control the intake speeds of oxygen and water vapor, so as to achieve precise automatic regulation of the proportion of water vapor and the oxygen content in the process; In Step 1, the generation and proportion control process of the water vapor is as follows: Pump water into the water vapor generator through a plunger pump, and convert the water into water vapor through the water vapor generator, which is used as the gas source of the water vapor in Step 1; among them, the proportion of water vapor in the mixed gas is regulated by controlling the liquid intake speed of the plunger pump; In Step 1, the generation and content control process of the oxygen is as follows: Use a high-purity oxygen storage tank as the gas source of the oxygen in Step 1; install a mass flowmeter on the pipeline between the high-purity oxygen storage tank and the water vapor generator, and regulate the oxygen content in the mixed gas by controlling the intake speed of the mass flowmeter; In Step 2, measure the proportion of water vapor and the oxygen content in the mixed gas by installing an oxygen content analyzer and a water vapor analyzer at the intake end of the heat treatment equipment.

2. The method for precisely automatically regulating the water vapor and oxygen content in the heat treatment process according to claim 1, characterized in that, In Step 3, the control of the intake speeds of oxygen and water vapor specifically is: Feed back the real-time proportion of water vapor and the real-time oxygen content in the mixed gas to the industrial control computer; The industrial control computer generates a control signal according to the difference between the real-time proportion of water vapor and the actual required proportion of water vapor, and / or the difference between the real-time oxygen content and the actual required oxygen content; Regulate the liquid intake speed of the plunger pump and / or the intake speed of the mass flowmeter through the control signal.

3. The method for precisely automatically regulating the water vapor and oxygen contents in a heat treatment process according to claim 2, wherein When the difference between the real-time proportion of water vapor and the actual required proportion of water vapor is positive, the control signal regulates the reduction of the liquid intake speed of the plunger pump; When the difference between the real-time proportion of water vapor and the actual required proportion of water vapor is negative, the control signal regulates the increase of the liquid intake speed of the plunger pump.

4. The method for precisely and automatically regulating the water vapor and oxygen contents in the heat treatment process according to claim 2, characterized in that When the difference between the real-time oxygen content and the actual required oxygen content is positive, the control signal regulates the reduction of the intake speed of the mass flowmeter; When the difference between the real-time oxygen content and the actual required oxygen content is negative, the control signal regulates the increase of the intake speed of the mass flowmeter.

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