Device for collecting and quantitatively determining propylene in circulating water

Abstract

The utility model belongs to the technical field of circulating water systems, and discloses a device for collecting and quantitatively measuring propylene in circulating water, which comprises a sample container, an ultrasonic oscillator, a strong brine tank and a peristaltic pump, an upper cover of the sample container is provided with a water inlet, a gas outlet, a communication port, a strong brine inlet and a nitrogen inlet and is correspondingly connected with a water pipe, a gas outlet pipe, a U-shaped pipe, a strong brine pipe and a nitrogen pipe, the other end of the water pipe is connected with a circulating water sampling port or a wastewater tank, the other end of the gas outlet pipe is connected with a gas chromatograph, and the U-shaped pipe is filled with strong brine; and the strong brine pipe is connected with a strong brine tank through a peristaltic pump. The gas phase volume change and the propylene concentration can be accurately metered, so that the mass of propylene dissolved in circulating water is obtained, the propylene leakage degree in a heat exchanger can be accurately judged, and potential safety hazards in the production process are reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of circulating water systems, and particularly relates to a device for collecting and quantitatively measuring propylene in circulating water. Background Art

[0002] The circulating cooling water system, used for heat exchange of process materials such as reactant gases, product gases, and propylene refrigeration, is the lifeblood of the entire methanol-to-olefins and ethylene cracking plant, playing a crucial role. During long-term operation, circulating water systems are prone to leakage of process media such as propylene, methanol, and C4. Propylene leaks can lead to increased dosage of the oxidizing biocide chlorpyrifos, changes in the cooling tower and sump, changes in the system's COD, toxic and combustible alarms, and changes in the circulating water heat exchanger.

[0003] Common methods for detecting propylene leaks include: 1) collecting circulating water from the heat exchanger inlet and outlet and measuring COD or TOC using instruments, but this cannot quantify light hydrocarbon components such as propylene; 2) adding salt to the collection container to form a saturated salt solution to separate the light hydrocarbon components, but this still cannot measure the degassed propylene, nor can it accurately quantify the amount of propylene dissolved in water. This inability to quantify propylene dissolved in circulating water makes it difficult to determine the severity of propylene leaks in heat exchangers, posing a significant safety hazard. Summary of the Invention

[0004] The utility model addresses the technical problem that the existing technology cannot quantitatively measure propylene in circulating water. It provides a device for collecting and quantitatively measuring propylene in circulating water, which can accurately measure the change in gas phase volume and propylene concentration, thereby obtaining the mass of propylene dissolved in the circulating water, accurately judging the degree of propylene leakage in the heat exchanger, and reducing safety hazards in the production process.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A device for collecting and quantitatively determining propylene in circulating water comprises a sample holder, an ultrasonic oscillator, a concentrated brine tank and a peristaltic pump. The sample holder is placed in a water bath of the ultrasonic oscillator. The upper cover of the sample holder is provided with a water inlet, an air outlet, a connecting port, a concentrated brine inlet and a nitrogen inlet, and is correspondingly connected to a water pipe, an air outlet pipe, a U-shaped pipe, a concentrated brine pipe and a nitrogen pipe. The water pipe, air outlet pipe, U-shaped pipe, concentrated brine pipe and nitrogen pipe are respectively provided with a first valve, a second valve, a third valve, a fourth valve and a fifth valve. The other end of the water pipe is connected to a circulating water sampling port or a wastewater tank, and the other end of the air outlet pipe is connected to a gas chromatograph. The U-shaped pipe is filled with concentrated brine, and the concentrated brine pipe is connected to the concentrated brine tank via a peristaltic pump.

[0007] In one technical solution, there is a scale on the vertical arm of the U-shaped tube.

[0008] In one technical solution, the water pipe, the air outlet pipe and the concentrated brine pipe are all soft hoses.

[0009] In one technical solution, the ultrasonic oscillator is a constant temperature ultrasonic oscillator.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] The upper cover of the sample container of the utility model is provided with a water inlet, an air outlet, a connecting port, a concentrated brine water inlet and a nitrogen inlet, and is correspondingly connected to a water pipe, an air outlet pipe, a U-shaped tube, a concentrated brine tube and a nitrogen tube; the other end of the water pipe is connected to a circulating water sampling port or a wastewater tank; the other end of the air outlet pipe is connected to a gas chromatograph; the U-shaped tube is filled with concentrated brine; the concentrated brine tube is connected to the concentrated brine tank via a peristaltic pump; a quantitative nitrogen drainage method is adopted to obtain the gas phase volume in the sample container; propylene in the water sample is then removed by a constant temperature water bath ultrasonic method; the removed propylene enters the upper nitrogen space; and the change in the gas phase volume is accurately measured by the U-shaped tube; then, saturated concentrated brine is added for pressurization, the mixed gas is introduced into the gas chromatograph, and the propylene concentration is calculated by an external standard method, thereby accurately obtaining the mass of propylene dissolved in the circulating water.

[0012] The device of the utility model has reasonable structural design and simple operation, and can also be used for collecting and quantitatively measuring other trace leaked gases in circulating water. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of the device for collecting and quantitatively measuring propylene in circulating water according to the present invention.

[0014] Markings in the accompanying drawings: 1 is a sample container, 2 is an ultrasonic oscillator, 3 is a water pipe, 4 is a first valve, 5 is an air outlet pipe, 6 is a second valve, 7 is a U-shaped tube, 8 is a third valve, 9 is a concentrated brine tank, 10 is a peristaltic pump, 11 is a concentrated brine pipe, 12 is a fourth valve, 13 is a nitrogen pipe, and 14 is a fifth valve. DETAILED DESCRIPTION

[0015] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of protection of the present invention.

[0016] like Figure 1As shown, the present invention is a device for collecting and quantitatively measuring propylene in circulating water, comprising a sample holder 1, an ultrasonic oscillator 2, a concentrated brine tank 9, and a peristaltic pump 10. The sample holder 1 is placed in the water bath of the ultrasonic oscillator 2. The upper cover of the sample holder 1 is provided with a water inlet, an air outlet, a connecting port, a concentrated brine inlet, and a nitrogen inlet, and is correspondingly connected to a water pipe 3, an air outlet pipe 5, a U-shaped tube 7, a concentrated brine pipe 11, and a nitrogen pipe 13. The water pipe 3, the air outlet pipe 5, the U-shaped tube 7, the concentrated brine pipe 11, and the nitrogen pipe 13 are respectively provided with a first valve 4, a second valve 6, a third valve 8, a fourth valve 12, and a fifth valve 14. The other end of the water pipe 3 is connected to a circulating water sampling port or a wastewater tank, the other end of the air outlet pipe 5 is connected to a gas chromatograph, the U-shaped tube 7 is filled with concentrated brine, and the concentrated brine pipe 11 is connected to the concentrated brine tank 9 via a peristaltic pump 10.

[0017] In one embodiment, to facilitate sampling and pouring, the upper cover of the sample container 1 and the sample container shell are movable. In addition, the water pipe 3, the air outlet pipe 5 and the concentrated brine pipe 11 connected to the corresponding outlets of the upper cover are all flexible tubes made of polytetrafluoroethylene, which are convenient for sampling and connecting instruments. When filling with nitrogen, the other end of the nitrogen pipe 13 can be connected to a nitrogen bottle or a syringe filled with nitrogen.

[0018] In one embodiment, the ultrasonic oscillator 2 of the present invention adopts a constant temperature ultrasonic oscillator, and there is a scale on the vertical arm of the U-shaped tube 7. Degassing is carried out by a constant temperature water bath ultrasonic method. The propylene in the water sample is released and enters the upper nitrogen space, which increases the gas phase pressure and causes the liquid level on the right side of the U-shaped tube to rise. The increased volume of the gas phase is accurately obtained by using the difference in the liquid level scale of the U-shaped tube.

[0019] The working process of the device for collecting and quantitative determination of the present invention is as follows: select a sample container 1 with a volume of 1000ml, blow the sample container 1 dry with nitrogen, tighten the cover of the sample container 1 and fill it with nitrogen; fill the U-shaped tube 7 with concentrated brine to a height of about half of the vertical tube, and record the initial horizontal scale; and close the first valve 4, the second valve 6, the third valve 8, the fourth valve 12 and the fifth valve 14, connect the other end of the water pipe 3 to the circulating water sampling port, disconnect the other end of the nitrogen pipe 13 from the nitrogen Connect the gas cylinder to the atmosphere, open the first valve 4 and the fifth valve 14, and when the circulating water fills the sample container 1, close the first valve 4 and the fifth valve 14, the sampling is completed, and the nitrogen in the sample container 1 is also discharged out of the bottle; connect the other end of the water pipe 3 to the waste water tank; connect the other end of the nitrogen pipe 13 to the nitrogen cylinder, open the fifth valve 14 and the first valve 4, and fill 200ml of nitrogen into the sample container 1. During the nitrogen filling process, the water sample in the sample container 1 is pressed into the waste water tank through the water pipe 3, and the nitrogen filling is completed. Then close the fifth valve 14 and the first valve 4. At this time, the water sample in the sample container 1 is 800 ml. Place the sample container 1 in a water bath of an ultrasonic oscillator 2 at a constant temperature of 50°C, and at the same time open the third valve 8 on the U-shaped tube 7 to perform ultrasonic analysis and degassing for 5 minutes. Since the solubility of propylene in water is very low, ultrasonic analysis for 5 minutes at 50°C can completely remove the propylene in the water sample. During the degassing process, propylene enters the upper nitrogen space, and the gas phase pressure increases, causing the liquid level on the right side of the U-shaped tube to rise. Record the final scale of the liquid level on the right side. After degassing, close the third valve 8 and use the scale difference to obtain the increased volume of the gas phase. Connect the other end of the outlet pipe 5 to a gas chromatograph (Agilent 7890), open the second valve 6 on the outlet pipe 5, turn on the peristaltic pump 10, inject saturated concentrated brine into the sample container 1, and introduce the upper mixed gas in the sample container 1 into the inlet of the gas chromatograph. The propylene concentration in the mixed gas can be quantitatively measured by the external standard method, and then the mass of propylene dissolved in the circulating water can be obtained.

[0020] This utility model uses a quantitative nitrogen drainage method to determine the gas phase volume within the sample container 1. Propylene in the water sample is then removed by ultrasonication in a constant-temperature water bath. The removed propylene enters the upper nitrogen space, and the change in gas phase volume is accurately measured via a U-shaped tube. The mixed gas is then pressurized by adding saturated concentrated brine, and introduced into a gas chromatograph. The propylene concentration is calculated using an external standard method, thereby accurately determining the mass of propylene dissolved in the circulating water. The utility model has a reasonable structural design and is simple to operate. It can also be used to collect and quantitatively measure other trace leaked gases in circulating water.

[0021] The embodiments described above are only preferred embodiments of the present invention and are only used to explain the present invention, not to limit the scope of implementation of the present invention. For those skilled in the art, it is of course possible to easily make other implementation methods by replacing or changing the technical content disclosed in this specification. Therefore, all changes and improvements made on the principles of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A device for collecting and quantitatively measuring propylene in circulating water, comprising a sample container (1), characterized in that: The invention also includes an ultrasonic oscillator (2), a concentrated brine tank (9) and a peristaltic pump (10). The sample container (1) is placed in the water bath of the ultrasonic oscillator (2). The upper cover of the sample container (1) is provided with a water inlet, an air outlet, a connecting port, a concentrated brine water inlet and a nitrogen inlet, and is correspondingly connected to a water pipe (3), an air outlet pipe (5), a U-shaped pipe (7), a concentrated brine pipe (11) and a nitrogen pipe (13). The water pipe (3), the air outlet pipe (5), the U-shaped pipe (7), the concentrated brine pipe (11) and the nitrogen pipe (13) are respectively provided with a first valve (4), a second valve (6), a third valve (8), a fourth valve (12) and a fifth valve (14). The other end of the water pipe (3) is connected to a circulating water sampling port or a wastewater tank, and the other end of the air outlet pipe (5) is connected to a gas chromatograph. The U-shaped pipe (7) is filled with concentrated brine, and the concentrated brine pipe (11) is connected to the concentrated brine tank (9) through a peristaltic pump (10).

2. The device for collecting and quantitatively measuring propylene in circulating water according to claim 1, characterized in that: There is a scale on the vertical arm of the U-shaped tube (7).

3. The device for collecting and quantitatively measuring propylene in circulating water according to claim 1, characterized in that: The water pipe (3), the air outlet pipe (5) and the concentrated brine pipe (11) are all flexible pipes.

4. The device for collecting and quantitatively measuring propylene in circulating water according to claim 1, characterized in that: The ultrasonic oscillator (2) is a constant temperature ultrasonic oscillator.

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