Circulating tetrahydrofuran solution preparation system

Abstract

The utility model relates to the technical field of tetrahydrofuran production, and provides a circulating tetrahydrofuran solution preparation system which comprises a refined tetrahydrofuran storage tank, a refined tetrahydrofuran feeding pipeline, an acetic acid storage tank and an acetic acid adding pipeline, and a first flow meter, a regulating valve and a mixer are sequentially arranged on the refined tetrahydrofuran feeding pipeline in the conveying direction. An acetic acid adding pump and a second flow meter are sequentially arranged on the acetic acid adding pipeline in the conveying direction, the tail end of the acetic acid adding pipeline is communicated to the refined tetrahydrofuran feeding pipeline, and after being mixed through the mixer, the acetic acid is conveyed into the circulating tetrahydrofuran storage tank through the refined tetrahydrofuran feeding pipeline; the control stability of the polymerization feeding system is improved, the workload and the operation difficulty of workers are reduced, and the product quality stability is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to tetrahydrofuran production technical field, specifically, relate to a kind of circulating tetrahydrofuran solution preparation system. BACKGROUND

[0002] The existing polytetrahydrofuran device in domestic mainly generates intermediate polytetramethylene ether diacetate under the action of catalyst by the ring-opening polymerization reaction of refined tetrahydrofuran, acetic acid and acetic anhydride, and its conversion rate is about 29.6%, so the remaining tetrahydrofuran will enter circulating tetrahydrofuran storage tank for recycling. Because by-product in production process can produce impurity, influence the conversion rate of polymerization reaction and product quality, when impurity accumulates to certain concentration, usually, the way that the material of circulating tetrahydrofuran storage tank is discharged periodically, circulating tetrahydrofuran solution is prepared again,

[0003] And circulating tetrahydrofuran solution is mainly refined tetrahydrofuran and acetic acid, in prior art, basically, artificial operation feeding is carried out, so that the addition amount of acetic acid solution and refined tetrahydrofuran solution cannot be accurately controlled, when refined tetrahydrofuran or acetic acid concentration fluctuates, it will directly influence the adjustment of polymerization feed, further influence the molecular weight and viscosity of polytetrahydrofuran product. UTILITY MODEL CONTENT

[0004] The utility model aims at providing a kind of circulating tetrahydrofuran solution preparation system, it realizes that refined tetrahydrofuran and acetic acid are prepared online, without manually controlling the amount of acetic acid and refined tetrahydrofuran, to avoid the problem that product quality is influenced due to the big fluctuation of feed adjustment;And greatly improve the stability of polymerization feed system control, reduce the workload and operation difficulty of staff, improve product quality stability.

[0005] The embodiment of the utility model is realized by the following technical scheme:

[0006] A circulating tetrahydrofuran solution preparation system, including refined tetrahydrofuran conveying unit and acetic acid conveying unit, the discharge end of refined tetrahydrofuran conveying unit and acetic acid conveying unit is conveyed to circulating tetrahydrofuran storage tank after mixing,

[0007] The refined tetrahydrofuran conveying unit includes refined tetrahydrofuran storage tank, refined tetrahydrofuran feed line,

[0008] The acetic acid conveying unit includes acetic acid storage tank, acetic acid addition pipeline,

[0009] First flowmeter, regulating valve and mixer are sequentially arranged on the refined tetrahydrofuran feed line along the direction of conveyance,

[0010] The acetic acid adding pipeline is sequentially provided with an acetic acid adding pump and a second flow meter in the conveying direction, and the end of the acetic acid adding pipeline is communicated to the refined tetrahydrofuran feeding pipeline, mixed by a mixer and then conveyed to a circulating tetrahydrofuran storage tank by the refined tetrahydrofuran feeding pipeline.

[0011] Further, a control unit for controlling the amount of acetic acid added is communicated between the regulating valve and the second flow meter.

[0012] Further, the control unit comprises a first flow controller and a second flow controller, one end of the first flow controller is connected with the regulating valve, the other end is connected with the second flow controller,

[0013] Further, a first flow transducer is further connected between the first flow controller and the first flow meter.

[0014] Further, a second flow transducer is further connected between the second flow controller and the second flow meter.

[0015] Further, the control unit further comprises a high pressure controller, which is communicated with the second flow controller.

[0016] Further, the second flow controller is further communicated with a transformer, one end of the acetic acid adding pump is connected with a driving motor, and the transformer is communicated with the driving motor.

[0017] Further, the regulating valve is a liquid level automatic regulating valve.

[0018] Further, the acetic acid adding pump is a pneumatic diaphragm pump.

[0019] Further, an on-line analyzer is further provided on the refined tetrahydrofuran feeding pipeline, and the on-line analyzer is located between the mixer and the circulating tetrahydrofuran storage tank.

[0020] The technical scheme of the utility model has at least the following advantages and beneficial effects:

[0021] The preparation system is rationally designed, the control unit is controlled by the external central control system, so that the refined tetrahydrofuran and acetic acid are prepared on-line, and the amount of acetic acid and refined tetrahydrofuran does not need to be manually controlled, so that the problem that the product quality is affected due to large feeding adjustment fluctuation is avoided, the stability of the polymerization feeding system control is greatly improved, the workload and operation difficulty of employees are reduced, and the product quality stability is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation to the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the premise of the drawings.

[0023] Figure 1 The flow chart of the circulating tetrahydrofuran solution preparation system provided by the embodiments of the present application is shown in the figure.

[0024] Figure: 1 - refined tetrahydrofuran storage tank, 2 - refined tetrahydrofuran feed line, 3 - first flow controller, 4 - first flow transmitter, 5 - regulating valve, 6 - first flow meter, 7 - mixer, 8 - online analyzer, 9 - circulating tetrahydrofuran storage tank, 10 - acetic acid storage tank, 11 - acetic acid addition pump, 12 - transformer, 13 - second flow controller, 14 - high pressure controller, 15 - second flow transmitter, 16 - variable frequency motor, 17 - second flow meter, 18 - acetic acid addition line. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application, and obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Embodiment 1

[0027] A circulating tetrahydrofuran solution preparation system, comprising a refined tetrahydrofuran conveying unit and an acetic acid conveying unit, the discharge end of the refined tetrahydrofuran conveying unit and the acetic acid conveying unit is conveyed to the circulating tetrahydrofuran storage tank 9 after mixing,

[0028] The refined tetrahydrofuran conveying unit comprises a refined tetrahydrofuran storage tank 1 and a refined tetrahydrofuran feed line 2; the refined tetrahydrofuran feed line 2 is sequentially provided with a first flow meter 6, a regulating valve 5 and a mixer 7 along the conveying direction,

[0029] The acetic acid delivery unit comprises an acetic acid storage tank 10 and an acetic acid adding pipeline 18; the acetic acid adding pipeline 18 is sequentially provided with an acetic acid adding pump 11 and a second flow meter 17 along the delivery direction; the end of the acetic acid adding pipeline 18 is communicated to the refined tetrahydrofuran feeding pipeline 2 and is delivered into the circulating tetrahydrofuran storage tank 9 after being mixed by the mixer 7; the refined tetrahydrofuran feeding pipeline 2 is further provided with an online analyzer 8, which is located between the mixer 7 and the circulating tetrahydrofuran storage tank 9.

[0030] In the embodiment, a control unit for controlling the acetic acid adding amount is communicated between the regulating valve 5 and the second flow meter 17, and the control unit is electrically connected with an external central control system. Specifically, the control unit comprises a first flow controller 3 and a second flow controller 13; one end of the first flow controller 3 is connected with the regulating valve 5, and the other end is connected with the second flow controller 13, so as to control the adding flow of the refined tetrahydrofuran by the first flow controller 3, and then control the adding amount of the acetic acid, thereby realizing online regulation and control of the adding amounts of the refined tetrahydrofuran and the acetic acid.

[0031] In the embodiment, a first flow transducer 4 is further connected between the first flow controller 3 and the first flow meter 6, so as to facilitate measurement of the flow of the refined tetrahydrofuran and conversion of the flow signal into a standard signal output, thereby facilitating remote monitoring and control.

[0032] In the embodiment, a second flow transducer 15 is further connected between the second flow controller 13 and the second flow meter 17, so as to facilitate measurement of the flow of the acetic acid and conversion of the flow signal into a standard signal output, thereby facilitating remote monitoring and control.

[0033] In the embodiment, the control unit further comprises a high-pressure controller 14, which is communicated with the second flow controller 13, so as to better control the pressure, flow and flow rate of the acetic acid.

[0034] In the embodiment, the second flow controller 13 is further communicated with a transformer 12; one end of the acetic acid adding pump 11 is connected with a driving motor; the transformer 12 is communicated with the driving motor; preferably, the driving motor is a variable frequency motor 16; by automatically adjusting the rotating speed of the variable frequency motor 16 and the acetic acid adding pump 11, the acetic acid reaches the corresponding flow.

[0035] In the embodiment, the regulating valve 5 is a liquid level automatic regulating valve 5.

[0036] In the embodiment, the acetic acid adding pump 11 is a variable frequency pump or a pneumatic diaphragm pump.

[0037] Working principle: when the circulating tetrahydrofuran waste liquid discharge is completed, the circulating tetrahydrofuran solution is prepared on line: the refined tetrahydrofuran is transported to the circulating tetrahydrofuran storage tank 9 by the refined tetrahydrofuran feeding pipeline 2, while the acetic acid is transported to the refined tetrahydrofuran feeding pipeline 2 by the acetic acid adding pipeline 18, and is mixed by the mixer 7, and then is transported to the circulating tetrahydrofuran storage tank 9 by the refined tetrahydrofuran feeding pipeline 2, so that the preparation of the circulating tetrahydrofuran solution is completed on line; more specifically:

[0038] First, the refined tetrahydrofuran adding flow is set by regulating the first flow controller 3, then the concentration of acetic acid in the circulating tetrahydrofuran solution is set, and then the second flow controller 13 is acted on (i.e. tetrahydrofuran flow x concentration of acetic acid), the second flow controller 13 is acted on the acetic acid adding pump 11 (preferably, a variable frequency pump is selected), the corresponding flow is achieved by automatically adjusting the rotating speed of the variable frequency motor 16, so that the addition amount of acetic acid can be controlled, and finally the concentration of acetic acid in the circulating tetrahydrofuran solution material can be displayed in real time by the on-line analyzer 8; therefore, the preparation system of the utility model controls the control unit by the external central control system, so that the refined tetrahydrofuran and acetic acid are prepared on line, and the amount of acetic acid and refined tetrahydrofuran does not need to be manually controlled, so that the problem that the product quality is affected due to large feeding adjustment fluctuation is avoided; and the stability of the polymerization feeding system control is greatly improved, the workload and operation difficulty of employees are reduced, and the product quality stability is improved.

[0039] The above is only the preferred embodiment of the utility model, and is not used for limiting the utility model, for the person skilled in the art, the utility model can have various changes and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A system for preparing a circulating tetrahydrofuran solution, characterized by comprising: The refined tetrahydrofuran conveying unit and the acetic acid conveying unit are connected to the circulating tetrahydrofuran storage tank through a mixing process. The refined tetrahydrofuran conveying unit comprises a refined tetrahydrofuran storage tank and a refined tetrahydrofuran feeding pipeline, wherein the first flow meter, the regulating valve and the mixer are sequentially arranged on the refined tetrahydrofuran feeding pipeline along the conveying direction. The acetic acid conveying unit comprises an acetic acid storage tank and an acetic acid adding pipeline, wherein the acetic acid adding pump and the second flow meter are sequentially arranged on the acetic acid adding pipeline along the conveying direction, and the end of the acetic acid adding pipeline is connected to the refined tetrahydrofuran feeding pipeline and then mixed by the mixer before being conveyed to the circulating tetrahydrofuran storage tank through the refined tetrahydrofuran feeding pipeline.

2. The recycled tetrahydrofuran solution preparation system according to claim 1, wherein The regulating valve is connected to the second flow meter through a control unit for controlling the amount of acetic acid added.

3. The recycled tetrahydrofuran solution preparation system according to claim 2, wherein The control unit comprises a first flow controller and a second flow controller, wherein one end of the first flow controller is connected to the regulating valve and the other end is connected to the second flow controller.

4. The recycled tetrahydrofuran solution preparation system according to claim 3, wherein The first flow controller is further connected to the first flow meter through a first flow transducer.

5. The recycled tetrahydrofuran solution preparation system according to claim 3, wherein The second flow controller is further connected to the second flow meter through a second flow transducer.

6. The recycled tetrahydrofuran solution preparation system according to claim 3, wherein The control unit further comprises a high-pressure controller connected to the second flow controller.

7. The recycled tetrahydrofuran solution preparation system according to claim 6, wherein The second flow controller is further connected to a transformer, and one end of the acetic acid adding pump is connected to a variable frequency motor, wherein the transformer is connected to the variable frequency motor.

8. The recycled tetrahydrofuran solution preparation system according to claim 1, wherein The regulating valve is a liquid level automatic regulating valve.

9. The recycled tetrahydrofuran solution preparation system according to claim 1, wherein The acetic acid adding pump is a variable frequency pump or a pneumatic diaphragm pump.

10. The recycled tetrahydrofuran solution formulation system of claim 1, wherein, An online analyzer is further arranged on the refined tetrahydrofuran feeding pipeline, and the online analyzer is located between the mixer and the circulating tetrahydrofuran storage tank.

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