PVC (polyvinyl chloride) seed sampling device adopting bulk method

Abstract

The utility model discloses a bulk method PVC (polyvinyl chloride) seed sampling device which comprises a sampling tank, a water inlet main pipe and a water outlet main pipe, a sampling pipe communicated with a prepolymerization kettle is arranged at the top of the sampling tank, a plunger valve is arranged at the position, close to the prepolymerization kettle, of the sampling pipe, a sampling feed valve is arranged at the position, close to the sampling tank, of the sampling pipe, and the sampling feed valve is communicated with the sampling tank. The top of the sampling tank is provided with a vacuumizing valve and a pressure gauge used for detecting the internal pressure of the sampling tank, the sampling pipe is also communicated with a replacement pipeline and a degassing pipeline, the replacement pipeline is provided with an inflation valve, the degassing pipeline is provided with a degassing valve, the outside of the sampling tank is provided with an interlayer, and the interlayer is communicated with the sampling pipe. One end of the water inlet main pipe and one end of the water outlet main pipe are both communicated with the interlayer, and a first valve and a second valve are arranged on the water inlet main pipe and the water outlet main pipe respectively. The seed sampling device is additionally arranged on an existing vinyl chloride prepolymerization kettle, conversion rate analysis and measurement are carried out on seeds, and then correction of a heat exchange value is guided.

Description

TECHNICAL FIELD

[0001] The utility model relates to polyethylene production technical field, specifically speaking, it is a kind of body method PVC seed sampling device. BACKGROUND

[0002] The conversion rate control of vinyl chloride bulk polymerization "seed" is extremely important, if the conversion rate is too low, PVC particle aggregation form is not stable, and the particle structure strength is not enough, and it is easy to be broken and crushed in the impact of pipeline elbow and other places in the transfer process, which can affect the particle characteristics of the final PVC resin obtained by subsequent polymerization;If the conversion rate is too high, the viscous PVC particles swollen by VCM are easy to stick and adsorb to the kettle wall, stirring paddle and baffle under the action of stirring and form the sticky kettle center, and aggravate the sticky kettle of prepolymerization. In order to make PVC "seed" particles have certain cohesion, the conversion rate of prepolymerization is generally controlled to be 8% to 12%.

[0003] The existing device controls the conversion rate of seed by heat exchange value, and the error is large due to the influence of many factors such as heat transfer, flow, temperature and the like, and the real conversion rate of seed cannot be determined. The existing device does not design seed sampling device, cannot analyze seed sampling, and cannot guide the correction of heat exchange value. UTILITY MODEL CONTENT

[0004] The technical problem to be solved by the utility model is to provide a kind of body method PVC seed sampling device, increase seed sampling device on the existing vinyl chloride prepolymerization kettle, measure the conversion rate of seed, and then guide the correction of heat exchange value.

[0005] The technical scheme for solving the above technical problem of the utility model is as follows: a kind of body method PVC seed sampling device, including sampling tank, water inlet main pipe and water outlet main pipe, the top of the sampling tank is equipped with sampling pipe for communicating with prepolymerization kettle, the sampling pipe is equipped with plunger valve near the prepolymerization kettle, the sampling pipe is equipped with sampling feed valve near the sampling tank, the top of the sampling tank is equipped with vacuum valve and pressure gauge for detecting the pressure inside the sampling tank, the sampling pipe is also communicated with displacement pipeline and degassing pipeline, the displacement pipeline is equipped with air valve, the degassing pipeline is equipped with degassing valve, the outside of the sampling tank is equipped with interlayer, one end of the water inlet main pipe and the water outlet main pipe is communicated with the interlayer, the water inlet main pipe and the water outlet main pipe are respectively equipped with first valve and second valve.

[0006] The beneficial effects of the above technical scheme are as follows:

[0007] Increase seed sampling device on the existing vinyl chloride prepolymerization kettle, measure the conversion rate of seed, and then guide the correction of heat exchange value.

[0008] On the basis of the above technical scheme, the utility model further can make improvement as follows.

[0009] Further, the top of the sampling tank is provided with an opening, a top cover for covering the opening is arranged at the opening, the sampling pipe is connected to the top cover, and the vacuum valve and the pressure gauge are connected to the top cover through pipelines.

[0010] The above further scheme has the beneficial effect of facilitating the installation and dismounting of components and the cleaning of the sampling tank.

[0011] Further, the top cover is connected to the opening through a flange.

[0012] The above further scheme has the beneficial effect of good fixing effect and facilitating assembly and dismounting.

[0013] Further, a manhole is arranged on the sampling tank.

[0014] The above further scheme has the beneficial effect of facilitating personnel to timely maintain the equipment.

[0015] Further, a plurality of supporting legs are fixedly connected to the bottom of the sampling tank.

[0016] The above further scheme has the beneficial effect of improving the stability of the tank body.

[0017] Further, the bottom of the sampling tank is provided in an arc shape.

[0018] The above further scheme has the beneficial effect of not easily damaging the human body during personnel movement.

[0019] Further, the sampling pipe is a flexible pipe.

[0020] The above further scheme has the beneficial effect of light weight and facilitating personnel movement.

[0021] Further, the utility model further comprises a low-temperature water inlet branch pipe and a high-temperature water inlet branch pipe, one end of the low-temperature water inlet branch pipe and the high-temperature water inlet branch pipe is communicated with the other end of the water inlet main pipe, and the low-temperature water inlet branch pipe and the high-temperature water inlet branch pipe are respectively provided with third valves and fourth valves.

[0022] The above further scheme has the beneficial effect of being capable of respectively controlling low-temperature and high-temperature hot water to enter the sampling tank and being convenient to operate.

[0023] Further, the utility model further comprises a low-temperature water outlet branch pipe and a high-temperature water outlet branch pipe, one end of the low-temperature water outlet branch pipe and the high-temperature water outlet branch pipe is communicated with the other end of the water outlet main pipe, and the low-temperature water outlet branch pipe and the high-temperature water outlet branch pipe are respectively provided with fifth valves and sixth valves.

[0024] The beneficial effect of the further scheme is that the low-temperature and high-temperature hot water can be discharged to the sampling tank respectively, and the operation is convenient.

[0025] Further, the first valve and the second valve are both ball valves.

[0026] The beneficial effect of the further scheme is that the operation is simple, and the sealing is good. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structural schematic view of the utility model;

[0028] Figure 2 It is a working state view of the utility model.

[0029] In the drawings, the component list represented by each sign is as follows:

[0030] 1, vacuum valve; 2, sampling feed valve; 3, pressure gauge; 4, inflation valve; 5, degassing valve; 6, first valve; 7, second valve; 8, third valve; 9, fourth valve; 10, fifth valve; 11, sixth valve; 12, sampling tank; 13, sampling pipe; 14, displacement pipeline; 15, degassing pipeline; 16, water inlet main pipe; 17, water outlet main pipe. DETAILED DESCRIPTION

[0031] The principles and characteristics of the utility model are described below in combination with the drawings, and the examples are only used for explaining the utility model, and are not used for limiting the range of the utility model.

[0032] Example 1:

[0033] As shown in the drawing, Figures 1-2 In the embodiment, a PVC seed sampling device of a body method includes a sampling tank 12, a water inlet main pipe 16 and a water outlet main pipe 17, the top of the sampling tank 12 is provided with a sampling pipe 13 for communicating with a prepolymerization kettle, the sampling pipe 13 is provided with a plunger valve near the prepolymerization kettle, the sampling pipe 13 is provided with a sampling feed valve 2 near the sampling tank 12, the top of the sampling tank 12 is provided with a vacuum valve 1 and a pressure gauge 3 for detecting the internal pressure of the sampling tank 12, the sampling pipe 13 is further communicated with a displacement pipeline 14 and a degassing pipeline 15, the displacement pipeline 14 is provided with an inflation valve 4, the degassing pipeline 15 is provided with a degassing valve 5, the outside of the sampling tank 12 is provided with a sandwich layer, one end of the water inlet main pipe 16 and the water outlet main pipe 17 is communicated with the sandwich layer, the water inlet main pipe 16 and the water outlet main pipe 17 are respectively provided with a first valve 6 and a second valve 7.

[0034] The embodiment has the beneficial effect that a seed sampling device is added to the existing vinyl chloride prepolymerization kettle to measure the conversion rate of the seed, thereby guiding the correction of the heat exchange value.

[0035] When the device is used, a certain amount of non-volatile terminator such as hydroquinone or sodium nonylphenol is added before sampling and weighed, and the mass is marked as M1 g. The first valve 6 and the second valve 7 are opened and low-temperature cold water is introduced. The plunger valve, the inflation valve 4, and the degassing valve 5 are closed. The vacuum valve 1, the sampling feed valve 2, and the pressure gauge 3 are opened. The sampling tank 12 and the sampling tube 13 are evacuated to a pressure ≤-0.086 Mpa in the sampling tank 12, and then the vacuum valve 1 is closed. The plunger valve is opened, and when the pressure in the sampling tank 12 is equal to the pressure of the prepolymerization kettle, the plunger valve is closed after a delay of 10 s. Then the sampling feed valve 2 is closed, the degassing valve 5 is opened, and the vinyl chloride in the sampling tube 13 is recovered. Then the degassing valve 5 is closed, the inflation valve 4 is opened, and the vinyl chloride in the sampling tube 13 is replaced. Then the degassing valve 5 is opened, and this cycle of replacement is repeated 3 times. When the pressure in the sampling tank 12 is ≤0.3 Mpa, the first valve 6 and the second valve 7 are closed, the sampling tank 12 is removed, and the water in the interlayer is drained and weighed, with the mass marked as M2 g. After weighing, the parts are reinstalled, the degassing valve 5 is opened, and the sampling feed valve 2 is slowly opened. When the pressure in the sampling tank 12 drops to ≤0.1 MPa, the first valve 6 and the second valve 7 are opened and high-temperature hot water is introduced. The degassing valve 5 is closed, the vacuum valve 1 is opened, and when the sampling tank 12 is evacuated to -0.086 Mpa, the degassing valve 5 is closed. The inflation valve 4 is opened until the pressure in the sampling tank 12 is 0.1 MPa, the inflation valve 4 is closed, and the degassing valve 5 is opened to evacuate the sampling tank 12. This cycle is repeated 3 times, the first valve 6 and the second valve 7 are closed, the sampling tank 12 is removed, and the PVC seed inside is taken out and dried and weighed, with the mass marked as M3 g. The seed conversion rate C = 〖(M3-10) / (M2-M1)〗*100%.

[0036] wherein, for example, Figure 1The, in the middle of the vinyl chloride bulk prepolymerization kettle reserved port, install plunger sampling valve; increase nitrogen replacement pipeline 14, degassing pipeline 15 and valve, it is convenient to replace before and after sampling; increase the water inlet main pipe 16 and the water outlet main pipe 17 and valve, and be connected with sampling tank 12, sampling stage and cooling seed in time, terminate reaction;Sample preparation stage is heated to sampling tank 12, accelerate the removal of residual monomer;Sampling tank 12 can withstand pressure 2.5MPa, tank volume 500ml;Sandwich, when sampling, low temperature cold water is passed into to cool seed and terminate reaction in time;Sample preparation stage, pass into high temperature hot water to make vinyl chloride monomer volatilize;Sampling port, sampling stage is used for seed sampling, sample preparation stage is used for degassing recovery vinyl chloride monomer;Vacuum port, sampling stage- vacuum sampling tank 12 and connecting pipeline again;Sample preparation stage-vacuum removal of residual monomer;Pressure gauge 3, for detecting vacuum pressure, and the pressure after sampling;Each pipe mouth is equipped with manual valve, it is convenient to disassemble.

[0037] Example 2

[0038] Preferably, on the basis of example 1, the top of the sampling tank 12 is provided with an opening, the opening is provided with a top cover for covering the opening, the sampling pipe 13 is connected with the top cover, and the vacuum valve 1 and the pressure gauge 3 are connected with the top cover through pipelines.

[0039] The beneficial effect of this embodiment is that the installation and disassembly of each component are facilitated, and the sampling tank 12 is easy to clean.

[0040] Example 3

[0041] Preferably, on the basis of example 2, the top cover is connected with the opening through flange.

[0042] The beneficial effect of this embodiment is that the flange connection mode has good fixing effect and is convenient for assembly and disassembly.

[0043] An alternative to the scheme of example 3 is that the top cover is connected with the opening through thread connection, which can also be clamped connection, to ensure sealing effect and facilitate opening and closing of the top cover.

[0044] Example 4

[0045] Preferably, on the basis of examples 1-3, a manhole is arranged on the sampling tank 12.

[0046] The beneficial effect of this embodiment is that personnel can timely overhaul the equipment.

[0047] Example 5

[0048] Preferably, on the basis of examples 1-4, a plurality of supporting legs are fixedly connected to the bottom of the sampling tank 12.

[0049] The embodiment has the beneficial effect of improving the stability of the tank.

[0050] The two legs are symmetrically arranged on the bottom of the sampling tank 12.

[0051] Embodiment 6

[0052] Preferably, on the basis of embodiments 1-5, the bottom of the sampling tank 12 is arranged in an arc shape.

[0053] The embodiment has the beneficial effect of not easily damaging the human body during the movement of personnel.

[0054] Further, the bottom of the sampling tank 12 can be a downward convex arc surface or a semispherical shape.

[0055] Further, the sampling tank 12 includes a top cover, a cylinder body, and a lower head, the cylinder body is a cylindrical cylinder, and the lower head is a semispherical shape, which is convenient for containing materials and has good sealing performance.

[0056] Embodiment 7

[0057] Preferably, on the basis of embodiments 1-6, the sampling pipe 13 is a flexible pipe.

[0058] The embodiment has the beneficial effect of being light in weight and convenient for personnel to move.

[0059] Further, the sampling pipe 13 can be of plastic material or flexible metal material.

[0060] Embodiment 8

[0061] Preferably, on the basis of embodiments 1-7, it further includes a low-temperature water inlet branch pipe and a high-temperature water inlet branch pipe, one end of the low-temperature water inlet branch pipe and the high-temperature water inlet branch pipe is in communication with the other end of the water inlet main pipe 16, and the low-temperature water inlet branch pipe and the high-temperature water inlet branch pipe are respectively provided with a third valve 8 and a fourth valve 9.

[0062] The embodiment has the beneficial effect of being able to control the low-temperature and high-temperature hot water entering the sampling tank respectively, and being convenient to operate.

[0063] It should be noted that the low-temperature cold water temperature of the low-temperature water outlet branch pipe is 0-10℃, and is preferably 5℃, and the high-temperature hot water temperature of the high-temperature water outlet branch pipe is 70-90℃, and is preferably 80℃.

[0064] Embodiment 9

[0065] Preferably, on the basis of Embodiments 1-8, a low-temperature water outlet branch pipe and a high-temperature water outlet branch pipe are further included, one end of each of the low-temperature water outlet branch pipe and the high-temperature water outlet branch pipe is in communication with the other end of the water outlet main pipe 17, and a fifth valve 10 and a sixth valve 11 are respectively arranged on the low-temperature water outlet branch pipe and the high-temperature water outlet branch pipe.

[0066] The embodiment has the beneficial effect that the low-temperature and high-temperature water can be respectively discharged into the sampling tank, and the operation is convenient.

[0067] Embodiment 10

[0068] Preferably, on the basis of Embodiments 1-9, the first valve 6 and the second valve 7 are both ball valves.

[0069] The beneficial effect of using the above further scheme is that the operation is simple and the sealing is good.

[0070] Embodiment 11

[0071] Preferably, on the basis of Embodiments 1-10, a PVC seed conversion rate measurement method is provided, and the body method PVC seed sampling device is used, and the method comprises the following steps:

[0072] S1: Before sampling, a mass M0 of hydroquinone is added to the sampling tank 12 and weighed, and the mass is marked as M1, the first valve 6 and the second valve 7 are opened and low-temperature cold water is introduced, the plunger valve, the inflation valve 4, and the degassing valve 5 are closed, the vacuum valve 1, the sampling feed valve 2, and the pressure gauge 3 are opened, the sampling tank 12 and the sampling pipe 13 are vacuumed to a pressure ≤-0.086 Mpa in the sampling tank 12, and then the vacuum valve 1 is closed;

[0073] S2: The plunger valve is opened, the pressure in the sampling tank 12 is observed until it is equal to the pressure of the prepolymerization kettle, the plunger valve is closed after a delay of 10S, then the sampling feed valve 2 is closed, the degassing valve 5 is opened, the vinyl chloride in the sampling pipe 13 is recovered, then the degassing valve 5 is closed, the inflation valve 4 is opened, the vinyl chloride in the sampling pipe 13 is replaced, then the inflation valve 4 is closed, and the vinyl chloride recovery and vinyl chloride replacement are alternately performed multiple times, when the pressure in the sampling tank 12 is ≤0.3 Mpa, the first valve 6 and the second valve 7 are closed, the sampling tank 12 is removed, the water in the interlayer is discharged, and then weighed, and the mass is marked as M2;

[0074] S3: Reinstall the sampling tank 12, then open the degassing valve 5, slowly open the sampling feed valve 2, when the pressure in the sampling tank 12 drops to ≤0.1MPa, open the first valve 6 and the second valve 7 and pass in high-temperature hot water, close the degassing valve 5, open the vacuumizing valve 1, when the sampling tank 12 is vacuumized to-0.086Mpa, close the degassing valve 5, open the aeration valve 4 until the pressure in the sampling tank 12 is 0.1MPa, close the aeration valve 4, alternately open and close the degassing valve 5 and the aeration valve 4 respectively for multiple times, close the first valve 6 and the second valve 7, remove the sampling tank 12 and take out the PVC seed inside, dry and weigh, and mark the mass as M3;

[0075] S4: Seed conversion rate C=(M3-M0) / (M2-M1)*100%.

[0076] The embodiment has the beneficial effects that the operation steps are simple, the running cost is low, the PVC seed conversion rate can be accurately measured, and the correction of the heat exchange value is facilitated.

[0077] Further, the value of M0 can be 10±0.01g.

[0078] It should be noted that M1 weighs the sampling tank 12 plus MO hydroquinone, M2 weighs the sampling tank 12 plus MO hydroquinone and liquid vinyl chloride and solid PVC, and M3 weighs MO hydroquinone plus solid PVC.

[0079] The number of times of circulation in steps S2 and S3 is performed according to the number of times set in advance, and is generally 2-4 times, preferably 3 times.

[0080] The beneficial effects of the utility model are:

[0081] The seed sampling device is added to the existing vinyl chloride prepolymerization kettle, the seed conversion rate is analyzed and measured, and the production (correction of the heat exchange value) is guided.

[0082] In the description of the utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "length", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "inner", "outer", "peripheral side", "circumferential direction" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the system or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0083] In the description of the utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0084] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0085] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0086] The above is only the preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A bulk PVC seed sampling device, characterized by: The invention comprises a sampling tank (12), a water inlet pipe (16) and a water outlet pipe (17), wherein the top of the sampling tank (12) is provided with a sampling pipe (13) for communicating with a prepolymerization kettle, the sampling pipe (13) is provided with a plunger valve near the prepolymerization kettle, the sampling pipe (13) is provided with a sampling feed valve (2) near the sampling tank (12), the top of the sampling tank (12) is provided with a vacuum valve (1) and a pressure gauge (3) for detecting the internal pressure of the sampling tank (12), the The sampling tube (13) is also connected to a replacement tube (14) and a degassing tube (15). The replacement tube (14) is provided with an inflation valve (4), and the degassing tube (15) is provided with a degassing valve (5). An interlayer is provided on the outside of the sampling tank (12). One end of the water inlet pipe (16) and the water outlet pipe (17) are both connected to the interlayer. The water inlet pipe (16) and the water outlet pipe (17) are respectively provided with a first valve (6) and a second valve (7).

2. The bulk PVC seed sampling device according to claim 1, characterized in that: The top of the sampling tank (12) is provided with an opening, and a top cover for sealing the opening is provided at the opening, the sampling tube (13) is connected to the top cover, and the vacuum valve (1) and the pressure gauge (3) are connected to the top cover via a pipeline.

3. The bulk PVC seed sampling device according to claim 2, characterized in that: The top cover is connected to the opening via a flange.

4. The bulk PVC seed sampling device according to claim 1, characterized in that: The sampling tank (12) is provided with a manhole.

5. The bulk PVC seed sampling device according to claim 1, characterized in that: A plurality of legs are fixedly connected to the bottom of the sampling tank (12).

6. The bulk PVC seed sampling device according to claim 1, characterized in that: The bottom of the sampling tank (12) is configured to be in an arc shape.

7. A bulk PVC seed sampling device according to any one of claims 1 to 6, characterized in that: The sampling tube (13) is a flexible tube.

8. A bulk PVC seed sampling device according to any one of claims 1 to 6, characterized in that: It also includes a low-temperature water inlet branch pipe and a high-temperature water inlet branch pipe, one end of each of the low-temperature water inlet branch pipe and the high-temperature water inlet branch pipe is connected to the other end of the water inlet main pipe (16), and a third valve (8) and a fourth valve (9) are respectively provided on the low-temperature water inlet branch pipe and the high-temperature water inlet branch pipe.

9. A bulk PVC seed sampling device according to any one of claims 1 to 6, characterized in that: It also includes a low-temperature water outlet branch pipe and a high-temperature water outlet branch pipe, one end of each of the low-temperature water outlet branch pipe and the high-temperature water outlet branch pipe is connected to the other end of the water outlet main pipe (17), and a fifth valve (10) and a sixth valve (11) are respectively provided on the low-temperature water outlet branch pipe and the high-temperature water outlet branch pipe.

10. A bulk PVC seed sampling device according to any one of claims 1 to 6, characterized in that: The first valve (6) and the second valve (7) are both ball valves.

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