Bubbling device capable of quantifying and controlling vapor concentration and concentration measurement method
阅读说明：本技术 一种可定量及可控制蒸气浓度的鼓泡装置及浓度测量方法 (Bubbling device capable of quantifying and controlling vapor concentration and concentration measurement method ) 是由 杨玖重 文武 张言 许鸣皋 潘洋 周忠岳 齐飞 于 2019-11-19 设计创作，主要内容包括：本发明涉及一种可定量及可控制蒸气浓度的鼓泡装置及浓度测量方法。所述装置包括依次连接的鼓泡罐(1)、定量系统(4)、真空系统(5)和反应器(6),及连接上述设备的管道。工作时,载气(3)顺序通入第一质量流量计/控制器(41)、第一阀门(42)、进气管(14)、微孔鼓泡器(16),形成气泡,将样品(2)蒸发气化从出气管(15)带出,顺序通过第三阀门(44)和第二质量流量计/控制器(45),并进入反应器(6)。利用基于传热原理的流量控制器的流量测量原理和质量守恒可以计算得到鼓泡混合蒸气中样品的流量和浓度；并且可以通过控制第二质量流量控制器(45)的流量,在遵守载气的进气、出气质量守恒前提下,实时快速控制混合蒸气中样品流量和浓度。(The invention relates to a bubbling device capable of quantitatively controlling vapor concentration and a concentration measuring method. The device comprises a bubbling tank (1), a quantitative system (4), a vacuum system (5) and a reactor (6) which are connected in sequence, and a pipeline for connecting the devices. During operation, carrier gas (3) is sequentially introduced into the first mass flow meter/controller (41), the first valve (42), the gas inlet pipe (14) and the micropore bubbler (16) to form bubbles, a sample (2) is evaporated and gasified and is taken out from the gas outlet pipe (15), and the bubbles sequentially pass through the third valve (44) and the second mass flow meter/controller (45) and enter the reactor (6). The flow and concentration of the sample in the bubbling mixed vapor can be calculated by utilizing the flow measurement principle and the mass conservation of the flow controller based on the heat transfer principle; and the flow and concentration of the sample in the mixed vapor can be rapidly controlled in real time by controlling the flow of the second mass flow controller (45) on the premise of keeping the mass conservation of the inlet gas and the outlet gas of the carrier gas.)
1. A bubbling device capable of quantitatively and controllably controlling vapor concentration, comprising:
comprises a bubbling tank, a quantitative system, a vacuum system and a reactor which are connected by pipelines;
the bubbling tank comprises a bubbling tank body, a bubbling tank body flange, a bubbling tank upper flange, an air inlet pipe, an air outlet pipe, a microporous bubbler, a constant-temperature container and a bubbling tank pressure transmitter; the upper part of the bubbling tank body is welded with a bubbling tank body flange and is in sealing connection with the bubbling tank upper flange; placing the sample in a bubbling tank body; the air inlet pipe and the air outlet pipe respectively penetrate through and are welded on the upper flange of the bubbling tank and extend into the tank body of the bubbling tank; placing a microporous bubbler in the sample; the position of the air outlet pipe is higher than the liquid level of the sample, and the air inlet pipe is inserted into the micropore bubbler; the bubbling tank body is arranged in a constant temperature container;
the dosing system comprises a first mass flow meter/controller, a first valve, a second valve, a third valve, and a second mass flow meter/controller; the air outlet of the first mass flow meter/controller, the air inlet of the first valve and the air inlet of the second valve are connected through a three-way pipeline; the air outlet of the first valve is connected with the air inlet of the air inlet pipe; the air outlet of the air outlet pipe is connected with the air inlet of the third valve; the air outlet of the second valve, the air outlet of the third valve and the air inlet of the second mass flow meter/controller are connected through a three-way pipeline;
the vacuum system comprises a fourth valve, a fifth valve and a vacuum pump; the air outlet of the second mass flow meter/controller, the air inlet of the fourth valve and the inlet of the reactor are connected through a three-way pipeline; the gas outlet of the fourth valve, the gas inlet of the fifth valve and the outlet of the reactor are connected through a three-way pipeline; a reactor pressure transmitter is arranged on the side surface of the reactor, and the electric signal output end of the reactor pressure transmitter is connected with the electric signal input end of a fifth valve; the vacuum pump is connected to the gas outlet of the fifth valve.
2. The apparatus as claimed in claim 1, wherein the bubbling device comprises:
the sample state is either a liquid phase or a solid phase.
3. The apparatus as claimed in claim 1, wherein the bubbling device comprises:
the micropore bubbler is a porous filter screen or sintered stainless steel and is used for controlling the bubbling size.
4. The apparatus as claimed in claim 1, wherein the bubbling device comprises:
the first mass flow meter/controller, the second mass flow meter/controller, including a thermal mass flow meter/controller, a coriolis mass flow meter/controller.
5. The apparatus as claimed in claim 1, wherein the bubbling device comprises:
the constant temperature container is filled with fluid comprising liquid nitrogen, saline water, oil and fine sand, the outer side of the constant temperature container is wrapped with a refrigerating and heating sleeve, and the constant temperature is kept in a range of-196 ℃ to 250 ℃ by a refrigerator and an electric heating mode.
6. The apparatus as claimed in claim 1, wherein the bubbling device comprises:
during aeration, the method comprises the following steps:
the method comprises the following steps that firstly, carrier gas, a first valve, a second valve, a third valve and a fourth valve are closed in sequence, the temperature of a thermostatic container is reduced to a preset temperature below the melting point of a sample, when the sample is solid, the first valve, the second valve, the third valve, the fourth valve and a fifth valve are opened in sequence, a first mass flow meter/controller is opened completely, a second mass flow meter/controller is opened completely, a vacuum pump is started, gas in a bubbling tank, a quantitative system, a reactor and a pipeline connected with the equipment is pumped out, and then the first mass flow meter/controller, the first valve, the second valve, the third valve, the second mass flow meter/controller and the fourth valve are closed in sequence;
the second step, the carrier gas is opened in sequence, the first mass flowmeter/controller is opened and controlled to preset flow, the second valve is opened, the second mass flowmeter/controller is fully opened, and the pressure of the reactor is controlled to be preset pressure through the negative feedback of the fifth valve and the reactor pressure transmitter; raising the temperature of the thermostatic container to a preset temperature above the melting point of the sample, sequentially closing the second valve, opening the first valve, slowly opening and controlling the opening degree of the third valve when the sample is in a liquid state, and maintaining the reading of the pressure transmitter of the bubbling tank to be constant and higher than the saturated vapor pressure of the sample; at the moment, the carrier gas sequentially passes through the first mass flow meter/controller, the first valve, the air inlet pipe and the micropore bubbler to form micro bubbles, volatilize the sample and carry the sample out of the air outlet pipe, pass through the third valve and the second mass flow meter/controller and enter the reactor.
7. A method for measuring the concentration of a sample of bubbling mixed steam by using the bubbling device capable of quantitatively and controllably measuring the concentration of steam according to claim 1, wherein:
the method calculates and controls the real-time flow and concentration of a sample by comparing the readings of the mass flowmeter/the controller before and after the comparison and combining a conversion formula, and specifically comprises the following steps:
the method comprises the following steps: correction factor s according to the molecular structure of the carrier gas1Density rho1Specific heat capacity CP,1Setting the first mass flowmeter/controller and controlling the carrier gas inlet flow rate to be V1(ii) a The actual total flow of the mixed steam after bubbling is VORDue to conservation of mass, the carrier gas flow therein is still V1Sample flow rate of V2Unknown to be solved; still in accordance with the carrier gasMolecular structure correction factor s1Density rho1Specific heat capacity CP,1Set the second mass flow meter/controller to show flow V at this timeOD；
Step two: ventilating according to the working steps, evaporating the sample by utilizing carrier gas bubbling to form bubbling mixed vapor and taking the bubbling mixed vapor out of the bubbling tank;
step three: reading or setting the second mass flowmeter/controller flow VODAnd calculating and controlling the real-time flow and concentration of the sample according to the mass conservation of the carrier gas and the working principle of the flow controller based on the heat transfer principle or the working principle of the Coriolis flow controller in combination with a conversion formula.
8. The method of measuring a concentration of a sample of bubbled mixed vapor of claim 7: the method is characterized in that:
the working steps comprise:
the method comprises the following steps that firstly, carrier gas, a first valve, a second valve, a third valve and a fourth valve are closed in sequence, the temperature of a thermostatic container is reduced to a preset temperature below the melting point of a sample, when the sample is solid, the first valve, the second valve, the third valve, the fourth valve and a fifth valve are opened in sequence, a first mass flow meter/controller is opened completely, a second mass flow meter/controller is opened completely, a vacuum pump is started, gas in a bubbling tank, a quantitative system, a reactor and a pipeline connected with the equipment is pumped out, and then the first mass flow meter/controller, the first valve, the second valve, the third valve, the second mass flow meter/controller and the fourth valve are closed in sequence;
the second step, the carrier gas is opened in sequence, the first mass flowmeter/controller is opened and controlled to preset flow, the second valve is opened, the second mass flowmeter/controller is fully opened, and the pressure of the reactor is controlled to be preset pressure through the negative feedback of the fifth valve and the reactor pressure transmitter; raising the temperature of the thermostatic container to a preset temperature above the melting point of the sample, sequentially closing the second valve, opening the first valve, slowly opening and controlling the opening degree of the third valve when the sample is in a liquid state, and maintaining the reading of the pressure transmitter of the bubbling tank to be constant and higher than the saturated vapor pressure of the sample; at the moment, the carrier gas sequentially passes through the first mass flow meter/controller, the first valve, the air inlet pipe and the micropore bubbler to form micro bubbles, volatilize the sample and carry the sample out of the air outlet pipe, pass through the third valve and the second mass flow meter/controller and enter the reactor.
9. The method of measuring a concentration of a sample of bubbled mixed vapor of claim 8: the method is characterized in that: further comprising:
the heat transfer principle-based flow controller works according to the principle, the flow and concentration of a sample in bubbling mixed steam are calculated according to a formula and are related to the reading of the second mass flow meter/controller, the reading of the first mass flow meter/controller, the reading of the carrier gas molecular structure correction factor, the density and the specific heat capacity, and the sample molecular structure correction factor, the density and the specific heat capacity, and the whole bubbling device meets the following formula:
VOR＝V1+V2
wherein, V1As inlet flow of carrier gas, V2The flow rate of the sample in the mixed vapor after bubbling, VODDisplaying the flow, V, for the second mass flow meter/controllerORThe actual total flow of the mixed steam after bubbling; a is1And a2The molar concentrations of the carrier gas and the sample in the bubbling mixed vapor are respectively; s1And s2The molecular structure correction factors of the carrier gas and the sample are respectively, the single atom molecule is 1.030, the diatomic molecule is 1.000, the triatomic molecule is 0.941, and the polyatomic molecule is 0.880; rho1And ρ2Densities of the gas phase at 101.325kPa and 298.15K for the carrier gas and sample, respectively; cP,1And CP,2Are the specific heat capacities of the carrier gas and sample at 298.15K, respectively.
10. The method of measuring a concentration of a sample of bubbled mixed vapor of claim 8: the method is characterized in that: further comprising:
the flowmeter/controller working principle calculation based on the heat transfer principle is carried out, the flow and the concentration of a sample in bubbling mixed steam are obtained through formula calculation and are related to the reading of the second mass flowmeter/controller, the reading of the first mass flowmeter/controller, the molecular structure correction factor of carrier gas, the density and the specific heat capacity, the molecular structure correction factor of the sample, the density and the specific heat capacity, and the flow and the concentration of the sample in the bubbling mixed steam satisfy the following formula:
V1as inlet flow of carrier gas, V2The flow rate of the sample in the mixed vapor after bubbling, VODDisplaying the flow rate for the second mass flow meter/controller; a is1And a2The molar concentrations of the carrier gas and the sample in the bubbling mixed vapor are respectively; s1And s2The molecular structure correction factors of the carrier gas and the sample are respectively, the single atom molecule is 1.030, the diatomic molecule is 1.000, the triatomic molecule is 0.941, and the polyatomic molecule is 0.880; rho1And ρ2Densities of the gas phase at 101.325kPa and 298.15K for the carrier gas and sample, respectively; cP,1And CP,2Are the specific heat capacities of the carrier gas and sample at 298.15K, respectively.
Technical Field
The invention belongs to the field of analysis and chemical industry sample injection quantification, and particularly relates to a bubbling device capable of quantifying and controlling vapor concentration and a concentration measurement method.
Background
Bubbling is an operation of a low-energy-consumption enhanced mass transfer and heat transfer process, and the bubbling method sample injection is one of solid and liquid sample injection methods commonly used in the industry and laboratories, and is widely applied to various industrial fields and experimental researches such as Chemical, Chemical and environmental protection, for example, preparation of a precursor of a process such as tritiated water Vapor, bubbling ALD (Atomic layer Deposition), CVD (Chemical Vapor Deposition), MOCVD (Metal-Organic Chemical Vapor Deposition), preparation of an experimental raw material gas by the bubbling method, bubbling and salt drying of concentrated seawater, and the like. Compared with injection modes such as an injection pump combined gasification tank and the like, the bubbling method has more advantages in the aspects of solid sample injection and high-boiling-point liquid sample injection, the injection pump cannot perform solid sample injection, the gasification difficulty behind the pump is large for the high-boiling-point liquid sample, if complete gasification cannot be realized, part of samples still exist in a liquid state, and the content of the gasified samples cannot be determined. The bubbling method utilizes the carrier gas to strengthen the volatilization process of the sample, so that the solid sample and the high-boiling-point liquid sample are directly converted into gas phase, and the gasification step can be omitted. Meanwhile, the vapor pressure property of the sample is utilized by bubbling, the bubbling is only related to the nature and the temperature of the sample, stable sample introduction can be well realized as long as the temperature of the sampled sample is well controlled, and on the other hand, the sample introduction concentration of the sample can be adjusted by changing the temperature of the sample and the vapor pressure of the sample.
The problem with the bubbling method is how to accurately quantify the sample. Particularly in the chemical field, certain important chemical reactions are involved, and the sample feeding amount and the sample feeding ratio of reactants need to be strictly controlled. Under industrial and laboratory conditions, the method of calculating the sample injection amount by using the saturated vapor pressure of a sample is the most common method, however, the method defaults that the sample in the bubbler is in a saturated vapor state all the time, and factors such as the structure of the bubbler, the bubbling conditions and the like can influence the bubbling state. In practice, the bubbler rarely meets the requirement, so that the method for calculating the sample injection amount by using the saturated vapor pressure has a great error and can only be used in occasions with low requirement on the sample injection amount precision. Other methods of quantification, such as level measurement and front and back weighing, have their own disadvantages. The liquid level measurement method can only aim at a liquid sample and cannot measure the sample introduction amount of a solid sample, and meanwhile, because the liquid level change of the liquid sample within a period of time can only be measured, the real-time observation of the sample introduction amount cannot be realized, the sample introduction amount of the sample cannot be controlled in real time, and therefore the expected sample introduction effect can be obtained by changing the flow rate of carrier gas or the temperature of the sample. Compared with the liquid level measurement method, the front-back weighing method can measure a solid sample, but has the same main defect as the liquid level measurement method, and cannot measure and control the sample injection amount of the sample in real time.
Other quantifier devices such as a chromatography, a spectral absorption method and an ultrasonic method can accurately quantify the bubbled sample, but the chromatography is expensive, an operator is required to have a certain chromatography basis and to be trained to master operation specifications and steps, and on the other hand, each spectrum acquisition of the chromatography needs a certain time and cannot meet the requirement of real-time measurement; infrared absorption spectroscopy (e.g., HORIBA IR-300 gas concentration detector) requires knowledge of the infrared absorption efficiency of the object being measured and is expensive; the ultrasonic method (such as a Piezocon gas concentration sensor manufactured by Veeco) utilizes the principle that the sound velocity is inversely proportional to the 1/2 th power of the average molecular mass of a mixed gas, and derives the gas concentration by measuring the sound velocity, but the molecular masses of a carrier gas and a sample need to be greatly different, and H is generally adopted2Or He as a carrier gas, limits certain applications.
In addition, the above method can only measure the concentration of the sample in the bubbling mixed vapor, and if the concentration of the sample needs to be controlled, the method can only be realized by changing the flow rate of the carrier gas, the temperature of the bubbling tank and the like, so that the conditions required by the process are difficult to quickly reach.
Disclosure of Invention
The technical problem to be solved by the invention is that when a bubbling method is used for sampling, the concentration of a sample in unsaturated steam at the outlet of a bubbling tank is accurately measured in real time, and the proportion of subsequent chemical reaction is more conveniently and quickly controlled by regulating and controlling the concentration of the sample in a bubbling mixed steam in a certain range in real time, so that the invention provides the bubbling device and the concentration measuring method which can quantitatively control the concentration of the steam.
The invention relates to a bubbling device capable of quantitatively controlling vapor concentration, which comprises a bubbling tank, a quantitative system, a vacuum system and a reactor, wherein the bubbling tank, the quantitative system, the vacuum system and the reactor are connected through pipelines;
the bubbling tank comprises a bubbling tank body, a bubbling tank body flange, a bubbling tank upper flange, an air inlet pipe, an air outlet pipe, a micropore bubbler, a constant temperature container and a bubbling tank pressure transmitter; the upper part of the bubbling tank body is welded with a bubbling tank body flange and is in sealing connection with the bubbling tank upper flange; placing the sample in a bubbling tank body; the air inlet pipe and the air outlet pipe respectively penetrate through and are welded on the upper flange of the bubbling tank and extend into the tank body of the bubbling tank; placing a microporous bubbler in the sample; the position of the air outlet pipe is higher than the liquid level of the sample, and the air inlet pipe is inserted into the micropore bubbler; the bubbling tank body is arranged in a constant temperature container;
the quantitative system comprises a first mass flow meter/controller, a first valve, a second valve, a third valve and a second mass flow meter/controller; the air outlet of the first mass flow meter/controller, the air inlet of the first valve and the air inlet of the second valve are connected through a three-way pipeline; the air outlet of the first valve is connected with the air inlet of the air inlet pipe; the air outlet of the air outlet pipe is connected with the air inlet of the third valve; the air outlet of the second valve, the air outlet of the third valve and the air inlet of the second mass flow meter/controller are connected through a three-way pipeline;
the vacuum system comprises a fourth valve, a fifth valve and a vacuum pump; the air outlet of the second mass flow meter/controller, the air inlet of the fourth valve and the inlet of the reactor are connected through a three-way pipeline; the gas outlet of the fourth valve, the gas inlet of the fifth valve and the outlet of the reactor are connected through a three-way pipeline; a reactor pressure transmitter is arranged on the side surface of the reactor, and the electric signal output end of the reactor pressure transmitter is connected with the electric signal input end of a fifth valve; the vacuum pump is connected to the gas outlet of the fifth valve.
Further, the sample state is a liquid phase or a solid phase.
Further, the microporous bubbler is made of a porous filter screen or sintered stainless steel and is used for controlling the bubbling size.
Further, the first mass flow meter/controller and the second mass flow meter/controller comprise a thermal mass flow meter/controller and a coriolis mass flow meter/controller.
Further, the constant temperature container is filled with fluid comprising liquid nitrogen, saline water, oil and fine sand, a refrigerating and heating sleeve is wrapped on the outer side of the constant temperature container, and the constant temperature is kept in a range of-196 ℃ to 250 ℃ by a refrigerator and an electric heating mode.
Further, the aeration is carried out according to the following steps:
the method comprises the following steps that firstly, carrier gas, a first valve, a second valve, a third valve and a fourth valve are closed in sequence, the temperature of a thermostatic container is reduced to a preset temperature below the melting point of a sample, when the sample is solid, the first valve, the second valve, the third valve, the fourth valve and a fifth valve are opened in sequence, a first mass flow meter/controller is opened completely, a second mass flow meter/controller is opened completely, a vacuum pump is started, gas in a bubbling tank, a quantitative system, a reactor and a pipeline connected with the equipment is pumped out, and then the first mass flow meter/controller, the first valve, the second valve, the third valve, the second mass flow meter/controller and the fourth valve are closed in sequence;
the second step, the carrier gas is opened in sequence, the first mass flowmeter/controller is opened and controlled to preset flow, the second valve is opened, the second mass flowmeter/controller is fully opened, and the pressure of the reactor is controlled to be preset pressure through the negative feedback of the fifth valve and the reactor pressure transmitter; raising the temperature of the thermostatic container to a preset temperature above the melting point of the sample, sequentially closing the second valve, opening the first valve, slowly opening and controlling the opening degree of the third valve when the sample is in a liquid state, and maintaining the reading of the pressure transmitter of the bubbling tank to be constant and higher than the saturated vapor pressure of the sample; at the moment, the carrier gas sequentially passes through the first mass flow meter/controller, the first valve, the air inlet pipe and the micropore bubbler to form micro bubbles, volatilize the sample and carry the sample out of the air outlet pipe, pass through the third valve and the second mass flow meter/controller and enter the reactor.
Furthermore, the invention provides a method for measuring the concentration of a bubbling mixed steam sample by using a bubbling device capable of quantitatively controlling the concentration of steam, which calculates and controls the real-time flow and concentration of the sample by comparing the readings of a mass flowmeter/a controller before and after the comparison and combining a conversion formula, and specifically comprises the following steps:
the method comprises the following steps: correction factor s according to the molecular structure of the carrier gas1Density rho1Specific heat capacity CP,1Setting the first mass flowmeter/controller and controlling the carrier gas inlet flow rate to be V1(ii) a The actual total flow of the mixed steam after bubbling is VORDue to conservation of mass, the carrier gas flow therein is still V1Sample flow rate of V2Unknown to be solved; correction factor s still according to the molecular structure of the carrier gas1Density rho1Specific heat capacity CP,1Set the second mass flow meter/controller to show flow V at this timeOD；
Step two: ventilating according to the working steps, evaporating the sample by utilizing carrier gas bubbling to form bubbling mixed vapor and taking the bubbling mixed vapor out of the bubbling tank;
step three: reading or setting the second mass flowmeter/controller flow VODAnd calculating and controlling the real-time flow and concentration of the sample according to the mass conservation of the carrier gas and the working principle of the flow controller based on the heat transfer principle or the working principle of the Coriolis flow controller in combination with a conversion formula.
Further, the working steps include:
the method comprises the following steps that firstly, carrier gas, a first valve, a second valve, a third valve and a fourth valve are closed in sequence, the temperature of a thermostatic container is reduced to a preset temperature below the melting point of a sample, when the sample is solid, the first valve, the second valve, the third valve, the fourth valve and a fifth valve are opened in sequence, a first mass flow meter/controller is opened completely, a second mass flow meter/controller is opened completely, a vacuum pump is started, gas in a bubbling tank, a quantitative system, a reactor and a pipeline connected with the equipment is pumped out, and then the first mass flow meter/controller, the first valve, the second valve, the third valve, the second mass flow meter/controller and the fourth valve are closed in sequence;
the second step, the carrier gas is opened in sequence, the first mass flowmeter/controller is opened and controlled to preset flow, the second valve is opened, the second mass flowmeter/controller is fully opened, and the pressure of the reactor is controlled to be preset pressure through the negative feedback of the fifth valve and the reactor pressure transmitter; raising the temperature of the thermostatic container to a preset temperature above the melting point of the sample, sequentially closing the second valve, opening the first valve, slowly opening and controlling the opening degree of the third valve when the sample is in a liquid state, and maintaining the reading of the pressure transmitter of the bubbling tank to be constant and higher than the saturated vapor pressure of the sample; at the moment, the carrier gas sequentially passes through the first mass flow meter/controller, the first valve, the air inlet pipe and the micropore bubbler to form micro bubbles, volatilize the sample and carry the sample out of the air outlet pipe, pass through the third valve and the second mass flow meter/controller and enter the reactor.
Further, the flow controller working principle based on the heat transfer principle is calculated, the sample flow and concentration in the bubbling mixed vapor are calculated through a formula and are related to the reading of the second mass flow meter/controller, the reading of the first mass flow meter/controller, the molecular structure correction factor, the density and the specific heat capacity of the carrier gas, and the molecular structure correction factor, the density and the specific heat capacity of the sample, and the whole bubbling device meets the following formula:
VOR＝V1+V2
wherein, V1As a carrier gasInlet flow rate, V2The flow rate of the sample in the mixed vapor after bubbling, VODDisplaying the flow, V, for the second mass flow meter/controllerORThe actual total flow of the mixed steam after bubbling; a is1And a2The molar concentrations of the carrier gas and the sample in the bubbling mixed vapor are respectively; s1And s2The molecular structure correction factors of the carrier gas and the sample are respectively, the single atom molecule is 1.030, the diatomic molecule is 1.000, the triatomic molecule is 0.941, and the polyatomic molecule is 0.880; rho1And ρ2Densities of the gas phase at 101.325kPa and 298.15K for the carrier gas and sample, respectively; cP,1And CP,2Are the specific heat capacities of the carrier gas and sample at 298.15K, respectively.
Further, the flowmeter/controller working principle based on the heat transfer principle is calculated, the flow rate and the concentration of the sample in the bubbling mixed steam are calculated through a formula and are related to the reading of the second mass flowmeter/controller, the reading of the first mass flowmeter/controller, the correction factor of the carrier gas molecular structure, the density and the specific heat capacity, the correction factor of the sample molecular structure, the density and the specific heat capacity, and the flow rate and the concentration of the sample in the bubbling mixed steam satisfy the following formula:
V1as inlet flow of carrier gas, V2The flow rate of the sample in the mixed vapor after bubbling, VODDisplaying the flow rate for the second mass flow meter/controller; a is1And a2The molar concentrations of the carrier gas and the sample in the bubbling mixed vapor are respectively; s1And s2The molecular structure correction factors of the carrier gas and the sample are respectively, the single atom molecule is 1.030, the diatomic molecule is 1.000, the triatomic molecule is 0.941, and the polyatomic molecule is 0.880; rho1And ρ2Densities of the gas phase at 101.325kPa and 298.15K for the carrier gas and sample, respectively; cP,1And CP,2Respectively carrier gas and sampleSpecific heat capacity of the product at 298.15K.
The beneficial technical effects of the invention are embodied in the following aspects:
1. by the method of respectively connecting the mass flow meters/controllers at the front and the rear of the bubbling tank, the steam in the gasification tank does not need to reach the saturation condition, and the partial pressure does not need to be measured and calculated.
2. The flow and the concentration of the sample in the mixed vapor can be rapidly controlled in real time by controlling the flow of the second mass flow controller on the premise of keeping the mass conservation of the inlet gas and the outlet gas of the carrier gas.
3. Furthermore, the evaporation rate and the vapor partial pressure of the sample can be changed by changing the temperature of the bubbling tank or the flow of the carrier gas, and the real-time rapid control of the flow and the concentration of the sample in the mixed vapor is realized by combining the real-time flow and the concentration feedback.
4. The method is suitable for low saturated vapor pressure samples which cannot be gasified by liquid pumping, such as high boiling point liquid, solid and substances which are easily decomposed by heating.
Drawings
FIG. 1 is a schematic view of a bubble apparatus capable of quantitatively and controllably controlling vapor concentration;
FIG. 2 is a schematic diagram of a liquid sample feeding vaporizer commonly used in the prior art;
FIG. 3 is a comparison of the bubbling quantification method and the injection pump liquid injection gasification method.
Sequence numbers in the upper figure: a bubbling tank 1, a sample 2, a carrier gas 3, a quantitative system 4, a vacuum system 5 and a reactor 6; a bubbling tank body 11, a bubbling tank body flange 12, a bubbling tank upper flange 13, an air inlet pipe 14, an air outlet pipe 15, a microporous bubbler 16, a constant temperature container 17 and a bubbling tank pressure transmitter 18; a first mass flow meter/controller 41, a first valve 42, a second valve 43, a third valve 44, a second mass flow meter/controller 45; a fourth valve 51, a fifth valve 52, a vacuum pump 53; a reactor pressure transmitter 61.
Detailed Description
The invention will now be further described by way of example with reference to the accompanying drawings.
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