Polyether production raw material conveying system

Abstract

The invention relates to the technical field of raw material conveying, in particular to a polyether production raw material conveying system which comprises a storage tank module used for storing glycerin, a valve module, a metering conveying pump, a check valve and a bubble mixing cavity, the storage tank module can control the temperature of the glycerin, and the bottom of the storage tank module is communicated with the valve module; the valve module is connected with a metering delivery pump through a pipeline, and the metering delivery pump is communicated with a check valve through a pipeline; the glycerin is heated through the storage tank module, the liquidity of the glycerin is improved, the glycerin is smoother in the conveying process, when the glycerin reaches the bubble mixing cavity and is about to be conveyed into the polyether production reaction kettle, low-temperature inert gas is sprayed out through the foaming hole pipe, the temperature of the glycerin can be restored, and the temperature of the glycerin is reduced. The reaction temperature control of the polyether production reaction kettle is prevented from being influenced by high temperature of glycerol.

Description

Technical Field

[0001] The invention relates to the technical field of raw material transportation, in particular to a polyether production raw material transportation system. Background Art

[0002] Polyether is a polymer with many unique physical and chemical properties. Polyether is formed by ring-opening polymerization of initiator and ethylene oxide, propylene oxide, butylene oxide, etc. under the action of catalyst. Initiator is an indispensable part of the raw materials for the production of polyether. The most commonly used initiator is glycerol, i.e., propylene glycol. Glycerol contains three hydroxyl groups in its molecular structure. These three hydroxyl groups can be used as active sites to undergo ring-opening polymerization with ethylene oxide, propylene oxide and other alkylene oxides. Glycerol is a colorless, odorless, sweet-tasting viscous liquid with high viscosity, and its viscosity is greatly affected by temperature. In the process of transporting glycerol, the traditional glycerol transport system directly transports glycerol. Due to its high viscosity, the flow efficiency in the pipeline is low and the flow is not smooth. Increasing the temperature can significantly reduce the viscosity of glycerol and greatly improve its fluidity without affecting the properties of glycerol. However, high-temperature glycerol input into the polyether production reactor will affect the strict temperature control in the polyether production reactor, thereby affecting the production quality of polyether. Summary of the invention

[0003] The object of the present invention is to provide a polyether production raw material conveying system to solve the problems raised in the above background technology.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a polyether production raw material conveying system, comprising a storage tank module for storing glycerin, a valve module, a metering delivery pump, a check valve and a bubble mixing chamber, wherein the storage tank module can control the temperature of glycerin, the bottom of the storage tank module is connected to the valve module, the valve module is connected to the metering delivery pump through a pipeline, the metering delivery pump is connected to the check valve through a pipeline, the check valve is connected to the bubble mixing chamber through a pipeline, the valve module is used to control the connection between the storage tank module and the metering delivery pump, the metering delivery pump can drive, convey and meter glycerin, the bubble mixing chamber is connected to a polyether production reactor, the bubble mixing chamber has cooling and foaming functions, the glycerin is heated in the storage tank module and cooled after reaching the bubble mixing chamber.

[0005] Preferably, a breathing valve, a temperature sensor and a temperature control spiral tube are provided in the storage tank module, and a liquid circulation temperature control system is provided outside the storage tank module.

[0006] Preferably, the breathing valve is used to balance the internal and external air pressure of the storage tank module, the temperature control spiral tube is connected to the liquid circulation temperature control system, and the temperature of the flowing medium in the temperature control spiral tube is controlled by the liquid circulation temperature control system, so that the temperature control spiral tube controls the temperature of the glycerin in the storage tank module, and the temperature sensor is used to detect the temperature of the glycerin in the storage tank module and send the detection signal to the liquid circulation temperature control system to realize closed-loop control.

[0007] Preferably, a foaming hole tube is provided in the bubble mixing chamber, a first air valve and an air source system are provided outside the bubble mixing chamber, and the first air valve is connected to the foaming hole tube through a pipeline.

[0008] Preferably, the gas source system is externally connected to a pressurized air pump, and the pressurized air pump is externally connected to a gas pressure regulating valve. The gas source system is used to provide an inert gas that does not react with glycerol. The pressurized air pump extracts the inert gas from the gas source system, increases the pressure of the inert gas, and then inputs it into the gas pressure regulating valve.

[0009] Preferably, the air pressure regulating valve can control the output air pressure, and the output pipeline of the air pressure regulating valve is respectively connected to a gas cooler and a second air valve, and the gas cooler is connected to the first air valve. After the air pressure regulating valve outputs the inert gas, the gas will be cooled by the gas cooler and then enter the first air valve.

[0010] Preferably, the output pipe of the second gas valve is connected and arranged between the check valve and the bubble mixing chamber, the first gas valve and the second gas valve can both control the switching of the gas, an input temperature probe is arranged at the input port of the bubble mixing chamber, and an output temperature probe is arranged at the output port of the bubble mixing chamber.

[0011] Preferably, a processing control module is provided outside the air pressure regulating valve, and a real-time control algorithm is provided in the processing control module. The real-time control algorithm can control the adjustment pressure of the air pressure regulating valve according to the detection data of the input temperature probe and the output temperature probe.

[0012] Preferably, the real-time control algorithm specifically includes: Assume that the detection temperature of the input temperature probe is , for time The output temperature of the temperature probe is , It is required to remain unchanged within the error range. The adjustment pressure of the air pressure regulating valve is ; Assume that the heat exchange between glycerol and gas satisfies the formula: ,in is the amount of heat transferred from glycerol to the gas per unit time. is a constant related to the heat exchange characteristics of the system. The rate of change of glycerol temperature Heat transfer rate and the specific heat capacity of glycerol and mass flow about, that is ,Will Substitution ,get .

[0013] Preferably, the control amount is adjusted according to the current error. , proportional control term ,in is the proportional gain, The larger the value, the faster the system responds to the error, but it may lead to system instability. Integral control is used to eliminate the steady-state error of the system. The integral term ,in is the integral gain; the differential control predicts the changing trend of the system, and the differential term ,in is the differential gain, Adjust the control amount according to the rate of change of the error; Total gas pressure control , specific parameters , and It was determined through experiments that As a control signal output, used to adjust the gas pressure.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The polyether production raw material conveying system of the present invention heats glycerin through a storage tank module to improve the fluidity of glycerin, making the conveying process smoother; when the glycerin reaches the bubble mixing chamber and is about to be input into the polyether production reactor, low-temperature inert gas is sprayed through the foaming hole tube to restore the temperature of the glycerin, thereby preventing the high temperature of the glycerin from affecting the reaction temperature control of the polyether production reactor; and the bubbles are filled in the glycerin, which not only increases the fluidity of subsequent conveying, but also a large number of bubbles can enhance the contact area and mixing effect of the glycerin and the subsequent reaction substances, which is beneficial to improving the efficiency and uniformity of reactions such as polyether production.

[0015] The present invention cooperates with the processing control module and the real-time control algorithm, etc., and can control the adjustment pressure of the air pressure regulating valve according to the detection data of the input temperature probe and the output temperature probe, so that the output temperature probe detects that the glycerol temperature output to the polyether production reactor remains unchanged within the error range, which is convenient for temperature control in the polyether production reactor; the algorithm changes the air pressure to change the jet flow of the foaming hole tube, thereby changing the cooling effect. Compared with the method of changing the cooling effect by controlling the temperature of the gas cooler, the algorithm reacts more quickly, because the temperature change of the gas cooler is a slow process, which is difficult to adapt to the real-time fluctuating glycerol temperature change, and the air pressure change is adjusted more quickly.

[0016] The present invention cooperates with the second air valve and other structures to close the first air valve and open the second air valve after the glycerin is transported, and the residual glycerin in the pipeline downstream of the check valve is quickly emptied by positive pressure inert gas, thereby reducing the residue in the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the module of the polyether production raw material delivery system of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1 The present invention provides a technical solution: a polyether production raw material delivery system, comprising a storage tank module for storing glycerin, a valve module, a metering delivery pump, a check valve and a bubble mixing chamber, the storage tank module can control the temperature of glycerin, the bottom of the storage tank module is connected with a valve module, the valve module is connected with a metering delivery pump through a pipeline, the metering delivery pump adopts a gear metering pump, and can meter and control the amount of glycerin delivered, the metering delivery pump is connected with the check valve through a pipeline, the check valve is connected with the bubble mixing chamber through a pipeline, the valve module is used to control the connection between the storage tank module and the metering delivery pump, the metering delivery pump can drive and deliver and meter glycerin, the bubble mixing chamber is connected with a polyether production reactor, the polyether production reactor is a reaction vessel in the polyether production process, and the initiator and ethylene oxide, propylene oxide, butylene oxide, etc. all need to be put into the polyether production reactor. The bubble mixing chamber has cooling and foaming functions, and the glycerin is heated in the storage tank module and cooled after reaching the bubble mixing chamber.

[0020] The storage tank module is provided with a breathing valve, a temperature sensor and a temperature control spiral tube, and the outside of the storage tank module is provided with a liquid circulation temperature control system. The temperature control spiral tube is a spiral hollow tube immersed in glycerin, and a medium flows inside it. The medium is connected to the liquid circulation temperature control system, and the liquid circulation temperature control system controls and heats the medium. The liquid circulation temperature control system includes a medium drive pump, a temperature sensing element and a heating element.

[0021] The breathing valve is used to balance the internal and external air pressure of the storage tank module. The temperature control spiral tube is connected to the liquid circulation temperature control system. The temperature of the flowing medium in the temperature control spiral tube is controlled by the liquid circulation temperature control system, so that the temperature control spiral tube can control the temperature of the glycerin in the storage tank module. The temperature sensor is used to detect the temperature of the glycerin in the storage tank module and send the detection signal to the liquid circulation temperature control system to realize closed-loop control.

[0022] A foaming hole tube is arranged in the bubble mixing chamber. The foaming hole tube is a closed tubular structure with a large number of micropores running through its surface. Inert gas is input into the foaming hole tube and discharged through the micropores, so that the glycerin flowing through the surface of the foaming hole tube can be foamed, so that the glycerin is filled with a large number of bubbles. A first air valve and an air source system are arranged outside the bubble mixing chamber. The first air valve is connected to the foaming hole tube through a pipeline. The air source system can generate inert gas. The inert gas is based on not reacting with glycerin and not affecting the production in the polyether production reactor. The air source system can be an inert gas storage tank.

[0023] The external connection of the gas source system is provided with a pressurized air pump, and the external connection of the pressurized air pump is provided with an air pressure regulating valve. The gas source system is used to provide an inert gas that does not react with glycerin. The pressurized air pump extracts the inert gas in the gas source system, increases the pressure of the inert gas, and then inputs it into the air pressure regulating valve.

[0024] The air pressure regulating valve can control the output air pressure. The air pressure regulating valve is a gas pressure regulating valve in the prior art, on which an electric actuator is arranged, and the gas pressure regulating valve can be controlled by the electric actuator. The output pipeline of the air pressure regulating valve is respectively connected with a gas cooler and a second air valve. The gas cooler is composed of heat exchange fins and a refrigeration device. The refrigeration device cools the heat exchange fins. When the inert gas flows through the heat exchange fins, it will be cooled by the heat exchange fins and output stable and low-temperature inert gas. The refrigeration device is composed of a compressor, a heat sink, a refrigerant and other structures; the gas cooler is connected to the first air valve. After the air pressure regulating valve outputs the inert gas, it will be cooled by the gas cooler and then enter the first air valve.

[0025] The output pipe of the second gas valve is connected and arranged between the check valve and the bubble mixing chamber. The first gas valve and the second gas valve can both control the switch of the gas. An input temperature probe is arranged at the input port of the bubble mixing chamber, and an output temperature probe is arranged at the output port of the bubble mixing chamber.

[0026] A processing control module is arranged outside the air pressure regulating valve, and the processing control module includes a single-chip microcomputer control chip and additional circuits. A real-time control algorithm is arranged in the processing control module, and the real-time control algorithm executes calculations in the single-chip microcomputer control chip. The real-time control algorithm can control the adjustment pressure of the air pressure regulating valve according to the detection data of the input temperature probe and the output temperature probe.

[0027] The real-time control algorithm specifically includes: Assume that the detection temperature of the input temperature probe is , for time The output temperature of the temperature probe is , It is required to remain unchanged within the error range. The adjustment pressure of the air pressure regulating valve is ; Assume that the heat exchange between glycerol and gas satisfies the formula: ,in is the amount of heat transferred from glycerol to the gas per unit time. is a constant related to the heat exchange characteristics of the system. The rate of change of glycerol temperature Heat transfer rate and the specific heat capacity of glycerol and mass flow about, that is ,Will Substitution ,get .

[0028] Adjust the control amount according to the current error. , proportional control term ,in is the proportional gain, The larger the value, the faster the system responds to the error, but it may lead to system instability. Integral control is used to eliminate the steady-state error of the system. The integral term ,in is the integral gain; the differential control predicts the changing trend of the system, and the differential term ,in is the differential gain, Adjust the control amount according to the rate of change of the error; Total gas pressure control , specific parameters , and It was determined through experiments that As a control signal output, used to adjust the gas pressure. , and We can first obtain some basic dynamic characteristics of the system through step response experiments, and then preliminarily determine the system according to empirical formulas or automatic tuning algorithms, such as the Ziegler-Nichols method. , and values, and then optimize these parameters through actual testing and adjustment to achieve good control effects.

[0029] During operation, the liquid circulation temperature control system heats the temperature control spiral tube, which is immersed in the glycerin in the storage tank module, and heats the glycerin to a certain temperature. The temperature sensor provided in the storage tank module monitors the temperature of the glycerin in the storage tank module, thereby realizing closed-loop control and stabilizing the glycerin in the storage tank module within a certain temperature.

[0030] By heating the storage tank module, the glycerin is kept in a high temperature state, at which time the fluidity of the glycerin is greatly improved. The valve module is opened, and the glycerin is transported through the metering delivery pump. After passing through the check valve, the glycerin enters the bubble mixing chamber.

[0031] The gas source system generates inert gas, which is pressurized by a pressure pump and then input into the gas pressure regulating valve. The gas pressure is adjusted by the gas pressure regulating valve. At this time, the second gas valve is closed, the first gas valve is opened, and the gas cooler is running. The gas in the gas pressure regulating valve is cooled after passing through the gas cooler, so that the gas becomes low-temperature gas. The low-temperature gas enters the foaming hole tube through the first gas valve, so that the glycerin in the bubble mixing chamber is filled with a large number of low-temperature inert bubbles, so that the glycerin is cooled, and the temperature of the glycerin is restored to avoid the high temperature of the glycerin affecting the reaction temperature control of the polyether production reactor; and the bubbles are filled in the glycerin, which not only increases the fluidity of subsequent transportation, but also a large number of bubbles can enhance the contact area and mixing effect between the glycerin and the subsequent reaction materials, which is conducive to improving the efficiency and uniformity of reactions such as polyether production. The setting of the above-mentioned gas cooler can reduce the temperature of the inert gas, have a better cooling effect on the glycerin, and save the consumption of inert gas.

[0032] After the fully quantitative glycerin is delivered, the valve module is first closed, the metering delivery pump is turned off, and then the first air valve is closed, the second air valve is opened, and the air pressure regulating valve increases the air pressure, so that the inert gas output by the pressurized air pump passes through the air pressure regulating valve and the second air valve and enters the downstream of the check valve, forcing the glycerin in the pipeline downstream of the check valve to be quickly discharged to reduce residue.

[0033] Since the distance between the storage tank module and the bubble mixing chamber may be far, although the output glycerin temperature of the storage tank module is constant within the error, after reaching the input temperature probe position in front of the bubble mixing chamber, the pipeline is affected by the external environment and the glycerin temperature may fluctuate. This application controls the adjustment pressure of the air pressure regulating valve according to the detection data of the input temperature probe and the output temperature probe by processing the control module and the real-time control algorithm, so that the output temperature probe detects that the glycerin temperature output to the polyether production reactor remains unchanged within the error range, which is convenient for temperature control in the polyether production reactor; this algorithm changes the air pressure to change the jet flow of the foaming hole tube, thereby changing the cooling effect. Compared with the method of changing the cooling effect by controlling the temperature of the gas cooler, the reaction is faster, because the temperature change of the gas cooler is a slow process, which is difficult to adapt to the real-time fluctuation of the glycerin temperature change, and the air pressure change is adjusted more quickly.

[0034] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polyether production raw material delivery system, comprising a storage tank module for storing glycerol, a valve module, a metering delivery pump, a check valve and a bubble mixing chamber, characterized in that: The storage tank module can control the temperature of glycerin. The bottom of the storage tank module is connected to a valve module. The valve module is connected to a metering pump through a pipeline. The metering pump is connected to a check valve through a pipeline. The check valve is connected to a bubble mixing chamber through a pipeline. The valve module is used to control the connection between the storage tank module and the metering pump. The metering pump can drive, transport and meter glycerin. The bubble mixing chamber is connected to a polyether production reactor. The bubble mixing chamber has cooling and foaming functions. The glycerin is heated in the storage tank module and cooled after reaching the bubble mixing chamber.

2. A polyether production raw material delivery system according to claim 1, characterized in that: The storage tank module is provided with a breathing valve, a temperature sensor and a temperature control spiral tube, and the outside of the storage tank module is provided with a liquid circulation temperature control system.

3. A polyether production raw material delivery system according to claim 2, characterized in that: The breathing valve is used to balance the internal and external air pressure of the storage tank module. The temperature control spiral tube is connected to the liquid circulation temperature control system. The temperature of the flowing medium in the temperature control spiral tube is controlled by the liquid circulation temperature control system, so that the temperature control spiral tube controls the temperature of the glycerin in the storage tank module. The temperature sensor is used to detect the temperature of the glycerin in the storage tank module and send the detection signal to the liquid circulation temperature control system to realize closed-loop control.

4. A polyether production raw material delivery system according to claim 1, characterized in that: A foaming hole tube is arranged in the bubble mixing chamber, a first air valve and an air source system are arranged outside the bubble mixing chamber, and the first air valve is connected to the foaming hole tube through a pipeline.

5. A polyether production raw material delivery system according to claim 4, characterized in that: The gas source system is externally connected to a pressurized air pump, and the pressurized air pump is externally connected to a pressure regulating valve. The gas source system is used to provide an inert gas that does not react with glycerol. The pressurized air pump extracts the inert gas from the gas source system, increases the pressure of the inert gas, and then inputs it into the pressure regulating valve.

6. A polyether production raw material delivery system according to claim 5, characterized in that: The air pressure regulating valve can control the output air pressure. The output pipeline of the air pressure regulating valve is respectively connected to a gas cooler and a second air valve. The gas cooler is connected to the first air valve. After the air pressure regulating valve outputs the inert gas, the gas will be cooled by the gas cooler and then enter the first air valve.

7. A polyether production raw material delivery system according to claim 6, characterized in that: The output pipe of the second gas valve is connected between the check valve and the bubble mixing chamber. Both the first gas valve and the second gas valve can control the switch of the gas. An input temperature probe is provided at the input port of the bubble mixing chamber, and an output temperature probe is provided at the output port of the bubble mixing chamber.

8. A polyether production raw material delivery system according to claim 7, characterized in that: A processing control module is arranged outside the air pressure regulating valve, and a real-time control algorithm is arranged in the processing control module. The real-time control algorithm can control the adjustment pressure of the air pressure regulating valve according to the detection data of the input temperature probe and the output temperature probe.

9. A polyether production raw material delivery system according to claim 8, characterized in that: The real-time control algorithm specifically includes: Assume that the detection temperature of the input temperature probe is , for time The output temperature of the temperature probe is , It is required to remain unchanged within the error range. The adjustment pressure of the air pressure regulating valve is ; Assume that the heat exchange between glycerol and gas satisfies the formula: ,in is the amount of heat transferred from glycerol to the gas per unit time. is a constant related to the heat exchange characteristics of the system. The rate of change of glycerol temperature Heat transfer rate and the specific heat capacity of glycerol and mass flow about, that is ,Will Substitution ,get .

10. A polyether production raw material delivery system according to claim 9, characterized in that: Adjust the control amount according to the current error. , proportional control term ,in is the proportional gain, The larger the value, the faster the system responds to the error, but it may lead to system instability. Integral control is used to eliminate the steady-state error of the system. The integral term ,in is the integral gain; the differential control predicts the changing trend of the system, and the differential term ,in is the differential gain, Adjust the control amount according to the rate of change of the error; Total gas pressure control , specific parameters , and It was determined through experiments that As a control signal output, used to adjust the gas pressure.

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