Catalyst concentration monitoring device in epoxy chloropropane fluidized bed reaction system

Abstract

The utility model relates to a catalyst concentration monitoring device in an epoxy chloropropane fluidized bed reaction system, which comprises a liquid-solid circulating fluidized bed, a filter, a turbidity sensor data collector and a computer processor, the first turbidity sensor is mounted in the middle of a tubular reactor of the liquid-solid circulating fluidized bed, and the second turbidity sensor is mounted in an upper dilute-phase area of a catalyst bin of the liquid-solid circulating fluidized bed. The online real-time particle concentration measuring device is novel in structure, flexible to mount, simple and convenient to operate, low in cost and capable of realizing online real-time measurement of particle concentration at different positions of a reaction system; and according to the particle concentration and the change condition of different positions, the operation stability monitoring of the reaction system of the liquid-solid circulating fluidized bed can be further obtained, and key parameters such as the smoothness of a circulating loop and the separation effect of a liquid-solid separator can be judged.

Description

Technical Field

[0001] The utility model relates to a concentration monitoring device, in particular to a catalyst concentration monitoring device in an epichlorohydrin fluidized bed reaction system. Background Art

[0002] Epichlorohydrin is an important organic chemical raw material and chemical intermediate, mainly used in the production of epoxy resins. It can also be used as a solvent, plasticizer, flame retardant and surfactant. In 2022, China's consumption of epichlorohydrin exceeded 1 million tons. With the continued demand for epoxy resins in application fields such as 5G, new energy vehicles, and wind power, epichlorohydrin has good growth prospects. The production processes of epichlorohydrin mainly include the chlorohydrin method, the glycerol method and the hydrogen peroxide method.

[0003] The chlorohydrin process is a traditional process for the production of epichlorohydrin. This process is mature and requires little investment, but it produces a large amount of three wastes. For every ton of epichlorohydrin produced, about 40 tons of difficult-to-treat chlorine-containing wastewater are produced. The glycerol process is currently the mainstream production process in China. Compared with the traditional chlorohydrin process, it has the advantages of mild reaction and relatively clean production process, but it still produces 3-4 tons or even more chlorine-containing wastewater for every ton of epichlorohydrin produced. In addition, the raw material glycerol mainly comes from biodiesel by-products, and almost all of it relies on imports. With the advancement of biodiesel preparation technology, the second-generation technology only produces biodiesel but not glycerol. The price and stable supply of glycerol raw materials have become important factors restricting the economic benefits and production capacity of the glycerol process of epichlorohydrin.

[0004] The hydrogen peroxide method has the characteristics of one-step reaction, only water as a byproduct, and is green and environmentally friendly. It is considered to be the most promising production route for epichlorohydrin. However, the existing reaction-controlled phase transfer process using heteropolyacid salts as catalysts has problems such as serious catalyst loss and poor economic efficiency. The fixed bed process using titanium silicon molecular sieve as catalyst has problems such as low effective utilization rate of hydrogen peroxide, rapid catalyst deactivation, and frequent regeneration.

[0005] In response to the above problems, the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences has developed a new process for producing epichlorohydrin by direct oxidation of chloropropane with hydrogen peroxide in a liquid-solid circulating fluidized bed. The new process can achieve efficient production of epichlorohydrin, significantly improve the effective utilization rate of hydrogen peroxide, greatly shorten the reaction time, greatly improve the selectivity of epichlorohydrin, and also realize online replacement of the catalyst. The comprehensive advantages of this process are outstanding.

[0006] One of the cores of the new process is the liquid-solid circulating fluidized bed reactor, which is a complex and highly coupled system. Its operation is more complicated than that of a fixed bed. The catalyst circulates in the system and each key unit affects each other. Therefore, it is very important to monitor the operating stability of the circulating fluidized bed reactor and quickly diagnose abnormal operation of the device. In addition, the study found that the catalyst concentration in the reactor has a significant effect on the reaction effect. A low catalyst concentration is likely to lead to incomplete reaction. A high catalyst concentration will cause a violent reaction at the reactor inlet, resulting in a large amount of heat release and difficult to control the reaction temperature, which affects the effective utilization rate of hydrogen peroxide and product selectivity. Therefore, it is critical for production operations to achieve online real-time measurement of the catalyst concentration in the reactor and detection of device operation stability.

[0007] The online measurement of particle concentration in traditional fluidized bed reactors is mostly done indirectly using differential pressure sensors, but this method is mainly applicable to gas-solid fluidized bed systems. In liquid-solid fluidized bed systems, the difference between particle density and liquid density is small, so the pressure difference caused by particle suspension is not obvious. In particular, in the process of producing epichlorohydrin by direct oxidation of propylene chloride with hydrogen peroxide in a liquid-solid circulating fluidized bed, the particle concentration in the reactor is low, with a mass fraction of mostly between 0.5% and 5.0%. For the methanol system, the particle density is 2000kg / m 3 For the liquid-solid mixed phase, the pressure change caused by 1wt% particle suspension is only about 0.1kPa / m, and the density of the liquid phase will also change and fluctuate as the reaction proceeds, which makes it impossible to use a differential pressure sensor to indirectly measure the particle concentration in the reactor. Therefore, it is very difficult to measure the catalyst concentration online and monitor the operation stability of the device in a liquid-solid circulating fluidized bed system with low particle concentration, such as direct oxidation of allyl chloride by hydrogen peroxide to produce epichlorohydrin.

[0008] Turbidimeter is an optical measuring instrument based on the principle of light scattering and transmission of liquid-solid two-phase system. It is a typical instrument for measuring particle concentration by optical method. It is currently mainly used in chemical, pharmaceutical, metallurgical, wastewater treatment and other industries to monitor the turbidity changes in the system to be measured. Invention patent CN112816378A discloses a real-time online measurement method for obtaining particle concentration in aerosol based on turbidimeter. During the operation, the gas-solid phase containing water vapor is sampled, cooled, and washed with water to obtain a liquid-solid suspension, and then the turbidity value of the liquid-solid phase is measured in real time. The mass concentration of particles in the aerosol is calculated by combining the total volume of cold water, sampling time, non-condensable gas flow rate and water vapor fraction. However, this method is complicated to operate and the procedure is cumbersome, and it cannot meet the requirements of online monitoring of particle concentration in chemical processes, especially liquid-solid circulating fluidized bed reactors. Utility Model Content

[0009] In view of the above situation, in order to overcome the defects of the prior art, the utility model provides a catalyst concentration monitoring device in an epichlorohydrin fluidized bed reaction system, which effectively solves the problems mentioned in the above background technology.

[0010] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: The utility model includes a liquid-solid circulating fluidized bed, a filter, a liquid phase buffer tank, a first turbidity sensor, a second turbidity sensor, a third turbidity sensor, a fourth turbidity sensor, a fifth turbidity sensor, a data acquisition device and a computer processor. The liquid-solid circulating fluidized bed is used for a liquid-solid circulating fluidized bed reaction for producing epichlorohydrin by a hydrogen peroxide method. The first turbidity sensor is installed in the middle of the tubular reactor of the liquid-solid circulating fluidized bed, and the second turbidity sensor is installed on the catalyst silo of the liquid-solid circulating fluidized bed. The third turbidity sensor is installed in the middle and lower dense phase area of ​​the catalyst silo of the liquid-solid circulating fluidized bed, a filter is installed on one side of the liquid-solid circulating fluidized bed, and a liquid phase buffer tank is installed on one side of the filter. The fourth turbidity sensor is located between the liquid-solid separator outlet of the liquid-solid circulating fluidized bed and the filter. The fifth turbidity sensor is installed in the liquid phase buffer tank. The output ends of the first turbidity sensor, the second turbidity sensor, the third turbidity sensor, the fourth turbidity sensor and the fifth turbidity sensor are connected to a data collector, and the output end of the data collector is connected to a computer processor.

[0011] Preferably, the catalyst of the liquid-solid circulating fluidized bed is microspherical particles with a particle density of 2000-5000 kg / m 3 The median particle size of the particles is 0.1-0.5mm.

[0012] Preferably, software for processing data of the first turbidity sensor, the second turbidity sensor, the third turbidity sensor, the fourth turbidity sensor and the fifth turbidity sensor is installed inside the computer processor.

[0013] Preferably, the first turbidity sensor, the second turbidity sensor, the third turbidity sensor, the fourth turbidity sensor and the fifth turbidity sensor are electrically connected to a data collector, and the data collector is electrically connected to a computer processor.

[0014] Preferably, the operating temperature of the liquid-solid circulating fluidized bed is 0-300° C., and the operating pressure is 0-10 MPa.

[0015] Preferably, the first turbidity sensor, the second turbidity sensor, the third turbidity sensor, the fourth turbidity sensor and the fifth turbidity sensor are made of one of austenitic stainless steel, Hastelloy alloy or polytetrafluoroethylene.

[0016] Beneficial effects: The utility model has novel structure, flexible installation, easy operation and low cost, and can realize online real-time measurement of particle concentration at different positions of the reaction system; it can also further obtain the stability monitoring of the operation of the liquid-solid circulating fluidized bed reaction system according to the particle concentration at different positions and its changes, judge the key parameters such as the patency of the circulation loop and the separation effect of the liquid-solid separator, improve the stability of the operation of the device and the simplicity of operation, and has the advantages of flexible operation, low cost, high precision, fast response speed and wide application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0019] Numbers in the figure: 1. Liquid-solid circulating fluidized bed; 2. Filter; 3. Liquid phase buffer tank; 4. First turbidity sensor; 5. Second turbidity sensor; 6. Third turbidity sensor; 7. Fourth turbidity sensor; 8. Fifth turbidity sensor; 9. Data acquisition device; 10. Computer processor. DETAILED DESCRIPTION

[0020] The following is combined with Figure 1 The specific implementation modes of the present utility model are further described in detail.

[0021] Embodiment 1, by Figure 1The utility model provides a catalyst concentration monitoring device in an epichlorohydrin fluidized bed reaction system, comprising a liquid-solid circulating fluidized bed 1, a filter 2, a liquid phase buffer tank 3, a first turbidity sensor 4, a second turbidity sensor 5, a third turbidity sensor 6, a fourth turbidity sensor 7, a fifth turbidity sensor 8, a data acquisition device 9 and a computer processor 10. The liquid-solid circulating fluidized bed 1 is used for a liquid-solid circulating fluidized bed reaction dedicated for producing epichlorohydrin by a hydrogen peroxide method. The first turbidity sensor 4 is installed in the middle of a tubular reactor of the liquid-solid circulating fluidized bed 1, and the second turbidity sensor 5 is installed in the catalyst silo of the liquid-solid circulating fluidized bed 1. In the upper dilute phase zone, the third turbidity sensor 6 is installed in the middle and lower dense phase zone of the catalyst silo of the liquid-solid circulating fluidized bed 1, a filter 2 is installed on one side of the liquid-solid circulating fluidized bed 1, and a liquid phase buffer tank 3 is installed on one side of the filter 2. The fourth turbidity sensor 7 is located between the liquid-solid separator outlet of the liquid-solid circulating fluidized bed 1 and the filter 2, and the fifth turbidity sensor 8 is installed in the liquid phase buffer tank 3. The output ends of the first turbidity sensor 4, the second turbidity sensor 5, the third turbidity sensor 6, the fourth turbidity sensor 7 and the fifth turbidity sensor 8 are connected to a data acquisition device 9, and the output end of the data acquisition device 9 is connected to a computer processor 10.

[0022] The catalyst of the liquid-solid circulating fluidized bed 1 is micro-spherical particles with a particle density of 2000-5000kg / m 3 The median particle size of the particles is 0.1-0.5mm.

[0023] The computer processor 10 has software installed therein for processing the data of the first turbidity sensor 4 , the second turbidity sensor 5 , the third turbidity sensor 6 , the fourth turbidity sensor 7 and the fifth turbidity sensor 8 .

[0024] The first turbidity sensor 4 , the second turbidity sensor 5 , the third turbidity sensor 6 , the fourth turbidity sensor 7 and the fifth turbidity sensor 8 are electrically connected to a data collector 9 , and the data collector 9 is electrically connected to a computer processor 10 .

[0025] The operating temperature of the liquid-solid circulating fluidized bed 1 is 0-300° C. and the operating pressure is 0-10 MPa.

[0026] The first turbidity sensor 4 , the second turbidity sensor 5 , the third turbidity sensor 6 , the fourth turbidity sensor 7 and the fifth turbidity sensor 8 are made of one of austenitic stainless steel, Hastelloy or polytetrafluoroethylene.

[0027] Working principle: When the utility model is used, the real-time data of the particle concentration at the measured position in the reactor can be obtained according to the first sensor, so as to realize the online real-time measurement of the catalyst concentration in the reactor; the particle concentration in the upper dilute phase zone in the catalyst silo can be obtained according to the second sensor, so as to judge the stability and smoothness of the particle circulation loop; the fluidization state of the catalyst in the dense phase zone in the catalyst silo and the changes in the particle properties can be obtained according to the third sensor; the separation effect of the liquid-solid separator can be obtained according to the changes in the particle concentration obtained by the fourth sensor, and the catalyst escape can be monitored; the changes in the properties of the liquid phase after the reaction can be obtained according to the fifth sensor. If the liquid phase shows oil-water two-phase separation or the color changes due to side reactions, there will be obvious changes in the turbidity value.

[0028] Beneficial effects: The utility model has novel structure, flexible installation, easy operation and low cost, and can realize online real-time measurement of particle concentration at different positions of the reaction system; it can also further obtain the stability monitoring of the operation of the liquid-solid circulating fluidized bed reaction system according to the particle concentration at different positions and its changes, judge the key parameters such as the patency of the circulation loop and the separation effect of the liquid-solid separator, improve the stability of the operation of the device and the simplicity of operation, and has the advantages of flexible operation, low cost, high precision, fast response speed and wide application range.

[0029] Through the personnel in this field, all the electrical components in this case are connected to their corresponding power supplies through wires, and appropriate controllers and encoders should be selected according to actual conditions to meet the control requirements. The specific connection and control sequence should refer to the following working principle, and the electrical connection between the electrical components is completed in the order of working in sequence. The detailed connection means are well-known technologies in this field. The following mainly introduces the working principles and processes, and no longer explains the electrical control.

[0030] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A catalyst concentration monitoring device in an epichlorohydrin fluidized bed reaction system, comprising a liquid-solid circulating fluidized bed (1), a filter (2), a liquid phase buffer tank (3), a first turbidity sensor (4), a second turbidity sensor (5), a third turbidity sensor (6), a fourth turbidity sensor (7), a fifth turbidity sensor (8), a data acquisition device (9) and a computer processor (10), characterized in that: The liquid-solid circulating fluidized bed (1) is used for a liquid-solid circulating fluidized bed reaction dedicated to producing epichlorohydrin by a hydrogen peroxide method. The first turbidity sensor (4) is installed in the middle of a tubular reactor of the liquid-solid circulating fluidized bed (1). The second turbidity sensor (5) is installed in the upper dilute phase region of a catalyst silo of the liquid-solid circulating fluidized bed (1). The third turbidity sensor (6) is installed in the middle and lower dense phase region of the catalyst silo of the liquid-solid circulating fluidized bed (1). A filter (2) is installed on one side of the liquid-solid circulating fluidized bed (1). A liquid phase buffer tank (3) is installed on one side, a fourth turbidity sensor (7) is located between the outlet of the liquid-solid separator of the liquid-solid circulating fluidized bed (1) and the filter (2), a fifth turbidity sensor (8) is installed in the liquid phase buffer tank (3), the output ends of the first turbidity sensor (4), the second turbidity sensor (5), the third turbidity sensor (6), the fourth turbidity sensor (7) and the fifth turbidity sensor (8) are connected to a data acquisition device (9), and the output end of the data acquisition device (9) is connected to a computer processor (10).

2. The device for monitoring catalyst concentration in an epichlorohydrin fluidized bed reaction system according to claim 1, characterized in that: The catalyst of the liquid-solid circulating fluidized bed (1) is microspherical particles with a particle density of 2000-5000 kg / m 3 The median particle size of the particles is 0.1-0.5mm.

3. The device for monitoring catalyst concentration in an epichlorohydrin fluidized bed reaction system according to claim 1, characterized in that: The computer processor (10) is internally installed with software for processing data from the first turbidity sensor (4), the second turbidity sensor (5), the third turbidity sensor (6), the fourth turbidity sensor (7) and the fifth turbidity sensor (8).

4. The device for monitoring catalyst concentration in an epichlorohydrin fluidized bed reaction system according to claim 1, characterized in that: The first turbidity sensor (4), the second turbidity sensor (5), the third turbidity sensor (6), the fourth turbidity sensor (7) and the fifth turbidity sensor (8) are electrically connected to a data collector (9), and the data collector (9) is electrically connected to a computer processor (10).

5. The device for monitoring catalyst concentration in an epichlorohydrin fluidized bed reaction system according to claim 1, characterized in that: The operating temperature of the liquid-solid circulating fluidized bed (1) is 0-300°C, and the operating pressure is 0-10MPa.

6. The device for monitoring catalyst concentration in an epichlorohydrin fluidized bed reaction system according to claim 1, characterized in that: The first turbidity sensor (4), the second turbidity sensor (5), the third turbidity sensor (6), the fourth turbidity sensor (7) and the fifth turbidity sensor (8) are made of one of austenitic stainless steel, Hastelloy or polytetrafluoroethylene.

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