阅读说明：本技术 基于微升级体积有机溶剂液体压缩率在线测试方法及系统 (Micro-upgrade volume-based organic solvent liquid compressibility online test method and system ) 是由 周旭 殷参 范洪涛 徐迎丽 杨东升 刘建峰 何通 于 2019-10-08 设计创作，主要内容包括：本发明涉及一种基于微升级体积有机溶剂液体压缩率在线测试方法及系统,利用液相泵液力端微升级容积,通过控制液相泵的往复运动,对有机溶剂进行在线压缩,实时读取液路系统压力值,将压力增量与压缩值进行关联,从而实现微升级体积的有机溶剂液体压缩率的在线测试。以解决高精度超高压液相泵输送有机溶剂过程中,液体溶剂的超高压压缩所造成的流量精度的影响；在超高压高精度有机溶剂输送时,通过有机溶剂压缩率的在线测试,为流路系统流量精度控制、脉动性及高压密封性能提供必备的数据支撑,实时进行压缩补偿,以保证恒流输送流量精度一致性指标、脉动性指标均能保持稳定。(The invention relates to an online test method and system for the liquid compression ratio of an organic solvent based on a micro-upgrading volume. The influence of flow precision caused by ultrahigh pressure compression of the liquid solvent in the process of conveying the organic solvent by the high-precision ultrahigh pressure liquid phase pump is solved; when the ultrahigh-pressure high-precision organic solvent is conveyed, the on-line test of the compression ratio of the organic solvent provides necessary data support for flow precision control, pulsation and high-pressure sealing performance of a flow path system, and compression compensation is carried out in real time so as to ensure that the consistency index and the pulsation index of constant-flow conveying flow precision can be kept stable.)

1. An organic solvent liquid compressibility online test method based on micro-upgrade volume is characterized by comprising the following steps:

(1) a stop valve is added at the outlet section of the liquid phase pump to cut off the organic solvent liquid passage, and the pressure of the organic solvent liquid in the liquid phase loop is zero at the moment;

(2) controlling a motor in the liquid phase pump to rotate so as to change the volume of the organic solvent liquid in the liquid phase loop, thereby realizing the compression of the organic solvent liquid and establishing the working pressure environment of the liquid phase pump;

(3) collecting motor data in real time through an encoder, calculating a motor rotation angle, and converting a pump head plunger movement stroke, namely the compression amount of the organic solvent liquid;

(4) acquiring the pressure value of the organic solvent liquid in the pump head in real time according to a pressure sensor at the hydraulic end of the liquid phase pump;

(5) correlating the pressure value and the compression amount of the organic solvent liquid and calculating the compression ratio of the organic solvent liquid;

(6) opening the stop valve to release pressure, recovering the pressure of the organic solvent liquid in the liquid phase loop to zero, re-executing the steps (1) to (5), and calculating the compression ratio again;

(7) and (4) solving the average value of the compression ratio, namely completing the online test of the compression ratio of the organic solvent liquid based on the micro-upgrade volume.

2. The on-line testing method for the compressibility of organic solvent liquid based on micro-upgrade volume according to claim 1, wherein: the liquid-phase pump group comprises a pump element A and a pump element B, wherein the pump element A comprises a main pump A and an auxiliary pump A, and the pump element B comprises a main pump B and an auxiliary pump B; the compression ratio of the organic solvent liquid in the pump element A is different from that of the organic solvent liquid in the pump element B.

3. The on-line testing method for the compressibility of organic solvent liquid based on micro-upgrade volume according to claim 1, wherein: the step (2) of compressing the organic solvent liquid specifically comprises the following steps:

(2.1) converting the rotary motion of the motor into the linear motion of a pump head plunger through a ball screw;

and (2.2) the plunger of the pump head moves forwards, the volume in the pump head is reduced, and the compression of the solvent is realized.

4. The on-line testing method for the compressibility of organic solvent liquid based on micro-upgrade volume according to claim 3, wherein: the organic solvent liquid in the liquid phase pump is gradually compressed by the rotation of the motor, and the working pressure environment of the liquid phase pump is not lower than 50 Mpa.

5. The on-line testing method for the compressibility of organic solvent liquid based on micro-upgrade volume according to claim 1, wherein: the formula of the compressed volume of the organic solvent in the step (3) is as follows:

ΔV＝πD²/4*Δx

in the formula: d is the diameter of the plunger, and deltax is the displacement difference of the plunger; Δ V represents a compression volume amount corresponding to the compression Δ x stroke.

6. The on-line testing method for the compressibility of organic solvent liquid based on micro-upgrade volume according to claim 1, wherein: and (4) acquiring the pressure value of the organic solvent in the step (4) in real time through a hydraulic end pressure sensor, wherein the sampling period is not more than 20 ms.

7. The on-line testing method for the compressibility of organic solvent liquid based on micro-upgrade volume according to claim 1, wherein: the step (5) correlates the pressure value and the compression amount of the organic solvent and calculates the compression ratio formula of the organic solvent liquid as follows:

K＝ΔV/(ΔP*V)

in the formula: k is the compression ratio under the corresponding pressure, V is the volume of the organic solvent, and delta V is the volume of the compression; Δ P represents the pressure difference before and after compression.

8. An on-line testing system for the liquid compressibility of organic solvents, which is realized by the on-line testing method for the liquid compressibility of organic solvents according to claim 1, and is characterized by comprising:

an initialization module: a stop valve is added at the outlet section of the liquid phase pump to cut off the organic solvent liquid passage, and the pressure of the organic solvent liquid in the liquid phase loop is zero at the moment;

a compression module: controlling a motor in the liquid phase pump to rotate so as to change the volume of the organic solvent liquid in the liquid phase loop, thereby realizing the compression of the organic solvent liquid and establishing the working pressure environment of the liquid phase pump;

the data acquisition and compression amount calculation module comprises: collecting motor data in real time through an encoder, calculating a motor rotation angle, and converting a pump head plunger movement stroke, namely the compression amount of the organic solvent liquid;

the pressure value real-time acquisition module: acquiring the pressure value of the organic solvent liquid in the pump head in real time according to a pressure sensor at the hydraulic end of the liquid phase pump;

a single compression ratio calculation module: correlating the pressure value and the compression amount of the organic solvent liquid and calculating the compression ratio of the organic solvent liquid;

an average compression ratio calculation module: opening the stop valve to release pressure, enabling the pressure of the organic solvent liquid in the liquid phase loop to be zero, and recalculating the compression ratio; the average value of the compression ratio is obtained.

9. The on-line testing system for compressibility of organic solvent liquids according to claim 8, wherein: the organic solvent compressed volume formula is:

ΔV＝πD²/4*Δx

in the formula: d is the diameter of the plunger, and deltax is the displacement difference of the plunger; Δ V represents a compression volume amount corresponding to the compression Δ x stroke.

10. The on-line testing system for compressibility of organic solvent liquids according to claim 8, wherein: correlating the pressure value and the compression amount of the organic solvent and calculating the compression ratio formula of the organic solvent liquid as follows:

K＝ΔV/(ΔP*V)

in the formula: k is the compression ratio under the corresponding pressure, V is the volume of the organic solvent, and delta V is the volume of the compression; Δ P represents the pressure difference before and after compression.

Technical Field

The invention relates to online measurement of a compression ratio of an organic solvent in a high-pressure state, is applied to ultrahigh-pressure liquid phase analysis, and belongs to the technical field of liquid phases.

Background

The high-precision ultra-high pressure liquid phase pump (UHPLC) is developed on the basis of a High Performance Liquid Chromatography (HPLC), the adopted stationary phase and a chromatographic column with high column efficiency can improve the pressure at the output end of the pump to 150MPa, the sample analysis time is shortened to 40s-2min from the range of 10min-30min obtained by HPLC, the sample analysis time is greatly shortened, and the cross contamination can be effectively reduced due to high sensitivity. The fields of medicine, biochemistry and food analysis have wide application requirements on UHPLC.

The compressibility of a fluid is the condition of a certain pressure or temperature difference of fluid particles. The property of which the volume or density can be varied. The volume of the high-precision ultrahigh-pressure liquid phase pump changes under the pressure of hundred megapascals. When the high-precision conveying is carried out, the compression quantity needs to be compensated through measurement, and necessary data support is provided for flow precision control, pulsation and high-pressure sealing performance of a flow path system, so that the stability of output flow precision is guaranteed.

The compressibility value of the fluid is determined by the ratio of volume difference between two different pressure values, at present, the change of the volume of the fluid is realized by the common motion of the primary reciprocating pump and the secondary reciprocating pump abroad, thereby determining the compression ratio of the fluid.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the online testing method and the online testing system for the liquid compressibility of the organic solvent with the micro-upgrading volume are used for solving the problem of influence on flow accuracy caused by compression of the liquid solvent in the process of conveying the organic solvent by the high-precision ultrahigh-pressure liquid phase pump, and compression compensation is realized through online measurement of the organic solvent, so that high-precision flow conveying is realized.

The technical solution of the invention is as follows:

an organic solvent liquid compressibility online test method based on micro-upgrade volume comprises the following steps:

(1) a stop valve is added at the outlet section of the liquid phase pump to cut off the organic solvent liquid passage, and the pressure of the organic solvent liquid in the liquid phase loop is zero at the moment;

(2) controlling a motor in the liquid phase pump to rotate so as to change the volume of the organic solvent liquid in the liquid phase loop, thereby realizing the compression of the organic solvent liquid and establishing the working pressure environment of the liquid phase pump;

(3) collecting motor data in real time through an encoder, calculating a motor rotation angle, and converting a pump head plunger movement stroke, namely the compression amount of the organic solvent liquid;

(4) acquiring the pressure value of the organic solvent liquid in the pump head in real time according to a pressure sensor at the hydraulic end of the liquid phase pump;

(5) correlating the pressure value and the compression amount of the organic solvent liquid and calculating the compression ratio of the organic solvent liquid;

(6) opening the stop valve to release pressure, recovering the pressure of the organic solvent liquid in the liquid phase loop to zero, re-executing the steps (1) to (5), and calculating the compression ratio again;

(7) and (4) solving the average value of the compression ratio, namely completing the online test of the compression ratio of the organic solvent liquid based on the micro-upgrade volume.

Further, the liquid-phase pump group comprises a pump element A and a pump element B, wherein the pump element A comprises a main pump A and an auxiliary pump A, and the pump element B comprises a main pump B and an auxiliary pump B; the compression ratio of the organic solvent liquid in the pump element A is different from that of the organic solvent liquid in the pump element B.

Further, the step (2) compresses the organic solvent liquid, specifically:

(2.1) converting the rotary motion of the motor into the linear motion of a pump head plunger through a ball screw;

and (2.2) the plunger of the pump head moves forwards, the volume in the pump head is reduced, and the compression of the solvent is realized.

Further, the organic solvent liquid in the liquid phase pump is gradually compressed by the rotation of the motor, and the working pressure environment of the liquid phase pump is not lower than 50 Mpa.

Further, the compressed volume amount formula of the organic solvent in the step (3) is as follows:

ΔV＝πD²/4*Δx

in the formula: d is the diameter of the plunger, and deltax is the displacement difference of the plunger; Δ V represents a compression volume amount corresponding to the compression Δ x stroke.

Further, the pressure value of the organic solvent in the step (4) is collected in real time through a hydraulic end pressure sensor, and the sampling period is not more than 20 ms.

Further, the step (5) correlates the pressure value of the organic solvent with the compression amount and calculates the compression ratio formula of the organic solvent liquid as:

K＝ΔV/(ΔP*V)

in the formula: k is the compression ratio under the corresponding pressure, V is the volume of the organic solvent, and delta V is the volume of the compression; Δ P represents the pressure difference before and after compression.

Furthermore, the invention also provides an on-line testing system for the liquid compressibility of the organic solvent, which comprises:

an initialization module: a stop valve is added at the outlet section of the liquid phase pump to cut off the organic solvent liquid passage, and the pressure of the organic solvent liquid in the liquid phase loop is zero at the moment;

a compression module: controlling a motor in the liquid phase pump to rotate so as to change the volume of the organic solvent liquid in the liquid phase loop, thereby realizing the compression of the organic solvent liquid and establishing the working pressure environment of the liquid phase pump;

the data acquisition and compression amount calculation module comprises: collecting motor data in real time through an encoder, calculating a motor rotation angle, and converting a pump head plunger movement stroke, namely the compression amount of the organic solvent liquid;

the organic solvent compressed volume formula is:

ΔV＝πD²/4*Δx

in the formula: d is the diameter of the plunger, and deltax is the displacement difference of the plunger; Δ V represents a compression volume amount corresponding to the compression Δ x stroke.

The pressure value real-time acquisition module: acquiring the pressure value of the organic solvent liquid in the pump head in real time according to a pressure sensor at the hydraulic end of the liquid phase pump;

a single compression ratio calculation module: correlating the pressure value and the compression amount of the organic solvent liquid and calculating the compression ratio of the organic solvent liquid;

the formula is as follows:

K＝ΔV/(ΔP*V)

in the formula: k is the compression ratio under the corresponding pressure, V is the volume of the organic solvent, and delta V is the volume of the compression; Δ P represents the pressure difference before and after compression.

An average compression ratio calculation module: opening the stop valve to release pressure, enabling the pressure of the organic solvent liquid in the liquid phase loop to be zero, and recalculating the compression ratio; the average value of the compression ratio is obtained.

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

(1) the method has good universality, and a main cylinder or an auxiliary cylinder of the liquid phase pump can be tested;

(2) the method has strong operability, the main cylinder and the auxiliary cylinder do not need to be linked to act during testing, and the main cylinder (or the auxiliary cylinder) is selected to rotate only by controlling the motor of the main cylinder (or the auxiliary cylinder) during testing, so that the volume of the organic solvent liquid in the main cylinder is changed, and compression is realized. At present, foreign countries realize the change of fluid volume through the common motion of a primary reciprocating piston pump and a secondary reciprocating piston pump, thereby determining the compression ratio of fluid, and the piston motions of the primary reciprocating pump and the secondary reciprocating pump are required to be mutually matched in time and are required to be crossed in the motion process of the primary reciprocating pump and the secondary reciprocating pump;

(3) the method is simple to operate, the liquid compression rate value can be tested by automatically controlling the stroke of the single-cylinder plunger, the main cylinder (or the auxiliary cylinder) is selected, the cylinder motor is only required to be controlled to drive the pump head plunger, and the stroke (displacement difference) of the pump head plunger is calculated by collecting motor data, namely the compression amount of the organic solvent liquid;

(4) the method has high testing efficiency and simple calculation process, and the compression ratio value under the pressure can be obtained by a group of data. Has been testedDuring the journey, when the pump head plunger initial displacement, read a pressure value, the pump head plunger moves forward, and the volume in the pump head reduces, and the pump head plunger is in this displacement department, reads another pressure value, calculates volume of compression volume amount delta V ═ pi D through twice displacement difference around through²And/4, Δ x, and calculating the compression ratio K as Δ V/(Δ P V) by combining the pressure difference.

Drawings

FIG. 1 is a flow chart of the method of the present invention;

FIG. 2 is a schematic view of the compression principle of the present invention;

FIG. 3 is a graph showing the compression ratio of methanol at different pressures.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

The invention provides an online test method and system for the liquid compressibility of an organic solvent based on a micro-upgrading volume. The influence of flow precision caused by ultrahigh pressure compression of the liquid solvent in the process of conveying the organic solvent by the high-precision ultrahigh pressure liquid phase pump is solved; when the ultrahigh-pressure high-precision organic solvent is conveyed, the on-line test of the compression ratio of the organic solvent provides necessary data support for flow precision control, pulsation and high-pressure sealing performance of a flow path system, and compression compensation is carried out in real time so as to ensure that the consistency index and the pulsation index of constant-flow conveying flow precision can be kept stable.

As shown in fig. 1, in order to achieve the above object, the method for on-line testing the compressibility of organic solvent liquid based on micro-upgrade volume according to the present invention comprises:

(1) a stop valve is added at the outlet section of the liquid phase pump to cut off the organic solvent liquid passage, and the pressure of the organic solvent liquid in the liquid phase loop is zero (gauge pressure is 0);

(2) controlling a motor in the liquid phase pump to rotate so as to change the volume of the organic solvent liquid in the liquid phase loop, thereby realizing gradual compression of the organic solvent liquid and achieving the working pressure environment of the liquid phase pump, wherein the liquid compression principle is shown in figure 2;

the method specifically comprises the following steps:

(2.1) converting the rotary motion of the motor into the linear motion of a pump head plunger through a ball screw;

(2.2) the plunger of the pump head moves forwards, the volume in the pump head is reduced, and the outlet section of the liquid phase pump is blocked, so that the compression of the solvent is realized;

(2.3) initial displacement of pump head plunger is x₀Corresponding to volume V of organic solvent₀The pump head plunger is driven by the motor to move forwards to a displacement of x₁The displacement corresponds to a volume of organic solvent of V₁；

(3) The invention can test the liquid compression rate value by automatically controlling the stroke of the single-cylinder plunger, selects the main cylinder (or the auxiliary cylinder), only needs to control the cylinder motor to drive the pump head plunger, and calculates the stroke (displacement difference) of the pump head plunger by collecting motor data, namely the compression amount of the organic solvent liquid;

specifically, motor data are collected in real time through an encoder, and a displacement value of a pump head plunger is calculated, so that the compression volume (volume difference before and after compression) of the organic solvent liquid is calculated;

the formula is as follows:

ΔV＝πD²/4*Δx

in the formula: d is the diameter of the plunger, and deltax is the displacement difference of the plunger of the pump head; Δ V denotes compression Δ x

The stroke corresponds to the compressed volume.

(4) Acquiring the pressure value of the organic solvent liquid in the pump head in real time according to a pressure sensor at the hydraulic end of the liquid phase pump; the sampling period of the pressure sensor is not more than 20ms so as to prevent numerical errors caused by the sampling period; initial displacement of pump head plunger is x₀Reading the pressure value of the pressure sensor to be P₀(typically atmospheric pressure values) and pump head plunger displacement of x₁Reading the pressure value of the pressure sensor to be P₁Pressure difference delta P before and after compression of pump head plunger is P₁-P₀；

(5) Correlating the pressure value and the compression amount of the organic solvent liquid and calculating the compression ratio of the organic solvent liquid;

the formula is as follows:

K＝ΔV/(ΔP*V)

in the formula: k is the compression ratio under the corresponding pressure difference, V is the volume of the organic solvent (the volume of the pump head and the initial organic solvent liquid in the pipeline before the inlet of the stop valve under normal temperature and normal pressure), and delta V is the volume of the compression; Δ P represents the pressure difference before and after compression.

(6) Opening the stop valve to release pressure, recovering the pressure of the organic solvent liquid in the liquid phase loop to zero, re-executing the steps (1) to (5), and calculating the compression ratio again;

(7) and (4) solving the average value of the compression ratio, namely completing the online test of the compression ratio of the organic solvent liquid based on the micro-upgrade volume.

The online testing method for the liquid compressibility of the organic solvent based on the micro-upgrade volume is realized based on a liquid phase pump. The liquid-phase pump group comprises a pump element A and a pump element B, wherein the pump element A comprises a main pump A and an auxiliary pump A, and the pump element B comprises a main pump B and an auxiliary pump B; the compression ratio of the organic solvent liquid in the pump element A is different from that of the organic solvent liquid in the pump element B. The working pressure environment of the liquid phase pump is generally not lower than 50Mpa, typically 100 Mpa.

According to the testing method provided by the invention, the main cylinder and the auxiliary cylinder do not need to be in associated action during testing, and the main cylinder (or the auxiliary cylinder) is selected to rotate only by controlling the motor of the main cylinder (or the auxiliary cylinder) during testing, so that the volume of the organic solvent liquid in the main cylinder is changed, and compression is realized.

Furthermore, the invention also provides an on-line testing system for the liquid compressibility of the organic solvent, which is characterized by comprising the following components:

an initialization module: a stop valve is added at the outlet section of the liquid phase pump to cut off the organic solvent liquid passage, and the pressure of the organic solvent liquid in the liquid phase loop is zero at the moment;

a compression module: controlling a motor in the liquid phase pump to rotate so as to change the volume of the organic solvent liquid in the liquid phase loop, thereby realizing the compression of the organic solvent liquid and establishing the working pressure environment of the liquid phase pump;

the data acquisition and compression amount calculation module comprises: collecting motor data in real time through an encoder, calculating a motor rotation angle, and converting a pump head plunger movement stroke, namely the compression amount of the organic solvent liquid;

the pressure value real-time acquisition module: acquiring the pressure value of the organic solvent liquid in the pump head in real time according to a pressure sensor at the hydraulic end of the liquid phase pump;

a single compression ratio calculation module: correlating the pressure value and the compression amount of the organic solvent liquid and calculating the compression ratio of the organic solvent liquid;

an average compression ratio calculation module: opening the stop valve to release pressure, enabling the pressure of the organic solvent liquid in the liquid phase loop to be zero, and recalculating the compression ratio; the average value of the compression ratio is obtained.

The following is further illustrated with reference to specific examples:

in the system operation process, the highest pressure of a liquid phase pump reaches 120MPa, and in order to ensure the smoothness of the output flow of the liquid phase pump and the accuracy of the concentration proportion of A, B pump output solvent, the compression compensation of a mixed solution needs to be dynamically adjusted on line. Thus, the compressibility of the solvent is accurately tested on-line.

Taking the A pump auxiliary cylinder and the organic solvent methanol as an example, the plunger is positioned at the rear zero point, the corresponding encoder value is-498072, and the initial displacement is x₀0mm, pressure sensor value P₀＝1.17MPa。

Automatically controlling the motor to move the plunger forward, reading the encoder value to-235929, and after compression, the displacement value of the plunger is x₁10mm, pressure sensor value P₁＝61.07MPa。

The plunger is in an initial position x₀₁With a corresponding encoder value of-445644, the initial displacement is x₀₁2mm, pressure sensor value P₀₁＝10.52MPa。

Automatically controlling the motor to move the plunger forward, reading the encoder value to-104857, and after compression, the displacement value of the plunger is x₁₁15mm, pressure sensor valueP₁₁＝102.03MPa。

The above process is repeated, and different displacement values after compression are sampled and recorded, and by calculation, when a certain volume V is 500 μ L, the methanol compression ratio is as shown in fig. 3.

The liquid phase pump project task book indexes provide that the system flow precision RSD is 0.06%, the pulse rate is 0.3MPa, and the highest system operation pressure is 120 MPa.

The compression ratio of the methanol organic solvent measured by the method is applied to the compensation of the flow rate of a liquid phase pump, and is verified under the condition of setting the flow rate to be 0.5mL/min, wherein the measured flow rate precision consistency RSD is 0.04%, and the pulsation rate is 0.223 MPa. The stability of liquid phase pump flow delivery has been guaranteed.

Those skilled in the art will appreciate that the invention may be practiced without these specific details.