CN221040270U - A virtual simulation platform for simulating the benzene production process - Google Patents

Abstract

The utility model discloses a virtual simulation platform for simulating a benzene production process, including a raw material pump, a benzene tower top pump, a first heat exchanger, a second heat exchanger, a benzene tower, a reboiler, a condenser, and a reflux tank; wherein, the first heat exchanger and the second heat exchanger are sequentially connected to the pipeline connecting the raw material pump and the middle part of the benzene tower, an outlet is provided at the top of the benzene tower and is connected to the reflux tank after passing through the condenser, and the reflux tank is divided into two branches through the control of the benzene tower top pump: the first branch is used to connect with the benzene tower, and the second branch is used for extraction; an outlet is provided at the bottom of the benzene tower: the first outlet is used to flow into the benzene tower after being heated by the reboiler through the pipeline, and the second outlet is used to send out the bottom of the tower. The utility model links various links such as the distillation process section process and chemical process control of chemical production of benzene to build a virtual simulation platform, which can improve production efficiency and reduce use costs, and at the same time enable groups without experimental conditions to understand the process flow of benzene purification and production in the aromatics fractionation process more specifically and clearly.

Description

A virtual simulation platform for simulating the benzene production process

Technical Field

The utility model relates to a virtual simulation platform for simulating a benzene production process, and belongs to the technical field of chemical process production control.

Background technique

Benzene is an important organic chemical raw material and solvent. The main production route at home and abroad is the PX (paraxylene) process. PX is a key process for producing important aromatic chemical raw materials such as benzene, toluene, and xylene. The main technical route of this process is: using naphtha, an intermediate product of the petrochemical process, as a raw material, after catalytic reforming or ethylene cracking, a reformed oil is obtained. The reformed oil contains less benzene components and higher toluene and xylene contents. After aromatic distillation extraction and aromatic distillation, a high-purity product can be obtained. The production of benzene is to use the typical process unit operation of distillation to extract and purify benzene from the mixed aromatics obtained from the petrochemical process. At present, 40% of the world's benzene products are produced using this technical route. The foreign PX production process is represented by the UOP company in the United States and the IFP technology in France. The domestic full-process process technology was broken through by Sinopec in 2011.

At present, the key equipment in the process of producing benzene is the benzene tower, and its process and control issues have always attracted much attention. However, due to the long research and development cycle and high risk of traditional process industrial production systems, as well as the huge consumption of infrastructure, human and material resources, it is not possible to carry out research using real equipment. It is necessary to use computer-related technology to simulate the production process and equipment. However, most of the current chemical production simulation devices are poorly constructed, and it is impossible to comprehensively consider the chemical process production section-level simulation devices. Therefore, a simulation device for chemical production of benzene is urgently needed to meet research needs.

Summary of the invention

The utility model provides a virtual simulation platform for simulating a benzene production process, which is used for simulating a benzene production process consistent with an actual process and providing a virtual environment for experimenters.

The technical scheme of the utility model is: a virtual simulation platform for simulating a benzene production process, comprising a raw material pump 1-1, a benzene tower top pump 1-2, a first heat exchanger 2-1, a second heat exchanger 2-2, a benzene tower 5, a reboiler, a condenser 7, and a reflux tank 10; wherein, the first heat exchanger 2-1 and the second heat exchanger 2-2 are sequentially connected to a pipeline communicating with the raw material pump 1-1 and the middle part of the benzene tower 5, an outlet is arranged at the top of the benzene tower 5, which is communicated with the reflux tank 10 after passing through the condenser 7, and the reflux tank 10 is divided into two branches through the control of the benzene tower top pump 1-2: the first branch is used for communicating with the benzene tower 5, and the second branch is used for extraction; an outlet is arranged at the bottom of the benzene tower 5: it is used for flowing into the benzene tower 5 after being heated by the reboiler through the pipeline, and is used for sending out the bottom material.

The reboiler is provided in two groups, specifically a first reboiler 4 - 1 and a second reboiler 4 - 2 , wherein the flow rate of the first reboiler 4 - 1 is controlled by a first pneumatic valve 3 .

The bottom of the benzene tower 5 is provided with a first thermometer 6-1, and the top of the tower is provided with a second thermometer 6-2.

The reflux tank 10 is provided with a nitrogen input end, an air output end and a waste liquid output end. The nitrogen input end is provided with a second pneumatic valve 8, the air output end is provided with a third pneumatic valve 9, and the waste liquid output end of the benzene tower reflux tank 10 discharges the waste liquid through a gate valve 13.

The first liquid level meter 12 - 1 and the second flow meter 16 - 2 provided on the reflux tank 10 cooperate with each other to control the valve opening of the fifth pneumatic valve 15 on the second branch line.

The benzene tower 5 is provided with a second liquid level meter 12 - 2 for displaying the liquid level of the benzene tower, and cooperates with the sixth pneumatic valve 17 and the flow meter 16 - 3 to control the liquid level of the benzene tower 5 .

The beneficial effects of the utility model are as follows: the utility model links together the distillation process of chemical production of benzene and various links such as chemical process control to build a virtual simulation platform, which can improve production efficiency and reduce the cost of use. At the same time, it can enable people without experimental conditions to understand the process flow of benzene purification and production in the aromatics distillation process more specifically and clearly, bring significant beneficial effects in training and education, and help promote the chemical industry to develop in a more sustainable and innovative direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of the overall process structure of the utility model;

Figure 2 is the main interface of the simulation experiment platform;

Figure 3 is the benzene tower liquid level control interface of the simulation experiment platform;

Figure 4 is the reflux tank level control interface of the simulation experiment platform;

Figure 5 is a reflux tank pressure control interface of the simulation experiment platform;

Figure 6 is the tower top/tower bottom temperature control interface of the simulation experiment platform;

Figure 7 is a historical trend curve interface in the simulation experiment platform;

FIG8 is a schematic diagram of the overall construction model of the bottom control module;

The numbers in the figure are: 1-1-raw material pump, 2-1-first heat exchanger, 2-2-second heat exchanger, 3-first pneumatic valve, 4-1-first reboiler, 4-2-second reboiler, 5-benzene tower, 6-1-first thermometer, 6-2-second thermometer, 7-condenser, 8-second pneumatic valve, 9-third pneumatic valve, 10-reflux tank, 11-pressure gauge, 12-1-first liquid level gauge, 12-2-second liquid level gauge, 13-gate valve, 1-2-benzene tower top pump, 14-fourth pneumatic valve, 15-fifth pneumatic valve, 16-1-first flow meter, 16-2-second flow meter, 16-3-third flow meter, 1-3 benzene tower bottom pump, 17-sixth pneumatic valve.

Detailed ways

The utility model is further described below in conjunction with the accompanying drawings and embodiments, but the content of the utility model is not limited to the described scope.

Embodiment 1: As shown in FIG1-8, a virtual simulation platform for simulating a benzene production process includes a raw material pump 1-1, a benzene tower top pump 1-2, a first heat exchanger 2-1, a second heat exchanger 2-2, a benzene tower 5, a reboiler, a condenser 7, and a reflux tank 10; wherein, the first heat exchanger 2-1 and the second heat exchanger 2-2 are sequentially connected to the pipeline connecting the raw material pump 1-1 and the middle part of the benzene tower 5, an outlet is provided at the top of the benzene tower 5, which is connected to the reflux tank 10 after passing through the condenser 7, and the reflux tank 10 is divided into two branches by the control of the benzene tower top pump 1-2: the first branch is used to connect with the benzene tower 5, and the second branch is used for extraction; an outlet is provided at the bottom of the benzene tower 5: it is used to flow into the benzene tower 5 after being heated by the reboiler through the pipeline, and is used to send the bottoms to the next process.

Furthermore, the reboiler is provided in two groups, specifically a first reboiler 4 - 1 and a second reboiler 4 - 2 , wherein the flow rate of the first reboiler 4 - 1 is controlled by a first pneumatic valve 3 .

Furthermore, the bottom of the benzene tower 5 is provided with a first thermometer 6-1, and the top of the tower is provided with a second thermometer 6-2.

Furthermore, the reflux tank 10 is provided with a nitrogen input end, an air output end and a waste liquid output end. The nitrogen input end is provided with a second pneumatic valve 8, and the air output end is provided with a third pneumatic valve 9. The benzene tower reflux tank 10 is provided with a pressure gauge 11 to measure the pressure inside the tank, so as to control the opening of the second pneumatic valve 8 and the third pneumatic valve 9 to realize the pressure control of the benzene tower reflux tank 10. The waste liquid output end of the benzene tower reflux tank 10 discharges the waste liquid through the gate valve 13.

Furthermore, the first liquid level meter 12 - 1 and the second flow meter 16 - 2 provided on the reflux tank 10 cooperate with each other to jointly control the valve opening of the fifth pneumatic valve 15 on the second branch line.

Furthermore, the benzene tower 5 is provided with a second liquid level meter 12 - 2 for displaying the liquid level of the benzene tower, and cooperates with the sixth pneumatic valve 17 and the flow meter 16 - 3 to control the liquid level of the benzene tower 5 .

The process principle of the utility model is: the second heat exchanger 2-2 and the first heat exchanger 2-1 are successively fed with the xylene tower top product produced in the subsequent process section and the raw material transmitted through the pipeline after the action of the raw material pump 1-1 for heat exchange, the raw material is preheated and fed from the middle of the benzene tower, and the tower bottom and the tower top of the benzene tower 5 are respectively provided with two thermometers for measuring the tower bottom and the tower top temperature in the benzene tower 5, and for process control of temperature changes in the tower (the first thermometer 6-1 on the benzene tower 5 controls the opening of the first pneumatic valve 3, thereby adjusting the steam feeding amount to achieve the purpose of controlling the tower bottom temperature; the second thermometer 6-2 on the benzene tower 5 controls the opening of the fourth pneumatic valve 14 After entering the benzene tower 5, the vapor and liquid two-phase materials flow in countercurrent in the tower, and interphase mass transfer and heat transfer occur. The non-volatile light components in the liquid phase are transferred to the vapor phase and further concentrated by the rectification section. The top of the benzene tower 5 is provided with an outlet that is connected to the reflux tank 10 after passing through the condenser 7. The sulfur-containing wastewater can be removed from the reflux tank 10. The components after the sulfur-containing wastewater is removed are controlled by the benzene tower top pump 1-2, and a part of them is controlled by the fourth pneumatic valve 14 to reflux into the tower. The first flowmeter 16-1 is provided on the pipeline flowing through, which can display the reflux amount in real time, and the other part passes through the fifth pneumatic valve 15 and the second flowmeter 1 6-2 is controlled to be extracted as distillate, and the non-volatile substances enter the tower kettle after heat and mass transfer, and the reflux tank 10 is also provided with a sewage outflow outlet, and the output of sewage is controlled by the gate valve 13; the first liquid level meter 12-1 on the reflux tank 10 cooperates with the second flow meter 16-2 to jointly control the valve opening of the fifth pneumatic valve 15, thereby realizing the control of the reflux tank liquid level, the pressure gauge 11 on the reflux tank 10 measures the pressure in the tank, and simultaneously controls the valve opening of the second pneumatic valve 8 and the third pneumatic valve 9 to realize the control of the pressure in the reflux tank of the benzene tower, and the first flow meter 16-1 can display the reflux amount; a part of the bottoms of the benzene tower 5 passes through two reboilers and then passes through The pipeline flows into the benzene tower 5 for treatment (the first reboiler 4-1 is heated by 1.0Mpa steam, and the first pneumatic valve 3 is used to control the amount of steam introduced. The second reboiler 4-2 uses the distillate from the top of the xylene tower in the subsequent process section as a hot fluid to achieve comprehensive heat recovery). A part of it is sent to the distillation tower in the subsequent process section to purify toluene and xylene through the sixth pneumatic valve 17 and the third flowmeter 16-3 under the control of the benzene tower bottom pump 1-3. At the same time, the second liquid level gauge 12-2 on the benzene tower 5 is used to display the liquid level of the benzene tower, and cooperates with the sixth pneumatic valve 17 and the third flowmeter 16-3 to control the liquid level of the benzene tower, thereby finally realizing closed-loop control of the liquid level of the benzene tower.

The virtual simulation platform uses KingSCADA to develop the human-computer interaction operation page and Simulink to complete the construction of the underlying control system. The constructed model can make the measured data closer to the real value, and provides a more efficient and safe solution for the related research on the production of benzene. At the same time, the historical experimental data measured by this platform can be stored in the database of KingSCADA for analysis and research.

The human-computer interaction control interface provides a convenient operation interface, allowing operators to control the process flow and conduct research more conveniently; the human-computer interaction control interface includes the main interface, benzene tower level control interface, reflux tank level control interface, reflux tank pressure control interface, tower top/bottom temperature control interface and historical trend curve interface, and each interface is provided with a button to jump between various interfaces through the main interface. As shown in Figures 2-7, the main interface includes the process flow of the aromatics distillation to produce benzene and buttons to jump to the remaining five interfaces.

In the main interface, press the raw material pump switch with the left mouse button to start the operation of the entire process flow, from which you can clearly see the entire process and the flow direction of each component. Press the "Benzene Tower Level Control" button in the main interface to jump to the benzene tower level control interface, which includes the benzene tower level curve display interface and the PID controller parameter adjustment interface. After completing the operation of this interface, press the "Return" button to return to the main interface; press the "Reflux Tank Level Control" button in the main interface to jump to the reflux tank level control interface. This interface is set the same as the benzene tower level control interface. After completing the operation of this page, press the return button to return to the main interface; press the "Reflux Tank Split Range Control" button from the main interface to jump to the loop tank pressure control interface. In addition to being able to display the reflux tank pressure curve in real time and adjust the controller parameters, this interface can also set the upper and lower pressure limits to observe the changes in the reflux tank pressure curve when the upper and lower limits change, which is closer to the real process operating system; in the main Press the "Tower Top/Tower Bottom Temperature Control" button in the interface to jump to the tower top/tower bottom temperature control interface. In addition to displaying the real-time curves of the tower top and tower bottom temperatures to adjust the parameters of the two controllers, this interface also has a "Decoupling/Non-Decoupling" button. The user can choose different control modes during operation; press the "Historical Trend Curve" button in the main interface to jump to the historical trend curve interface. In this interface, there are multiple function buttons. In the multi-selection box "Parameter" button, you can select the curve type to be queried. Press the "Historical Curve Query" button to query the trend curve of this type of curve in different time periods. Select "Get Curve Maximum Value" to get the maximum value of the curve in this time period, select the "Get Curve Minimum Value" button to get the minimum value of the curve, and select the "Get Curve Average Value" button to calculate the average value of the curve. Finally, select the "Return" button to return to the main interface. At this point, all operations on the human-computer interaction interface in the virtual simulation platform are completed.

As shown in Figure 8, the underlying control includes cascade control, decoupling control and split-range control. According to the actual needs of the process, the benzene tower liquid level control and the reflux tank liquid level control use cascade control, the reflux tank pressure uses split-range control, and the benzene tower/tower kettle temperature uses decoupling control. There is a coupling relationship between the various control schemes. Specifically, in the temperature control of the tower top/tower bottom, since the tower top and tower bottom temperatures are highly coupled, the temperatures are highly correlated when controlling the two temperatures. Therefore, a decoupling control scheme is used to achieve decoupling control of the tower top and tower bottom temperatures. Since flow fluctuations may cause large fluctuations in the liquid level, in the liquid level control of the benzene tower 5 and the reflux tank 10, a cascade control scheme is used to achieve liquid level control, which can effectively reduce the impact of flow fluctuations on the liquid level. When controlling the pressure of the reflux tank 10, since it is necessary to control the opening of two valves to achieve pressure control, the reflux tank pressure control uses a split-range control scheme. The top temperature of the benzene tower is determined by the reflux volume that will flow into the tower. At the same time, the size of the reflux volume will affect the changes in the reflux tank liquid level and the benzene tower liquid level. The pressure control of the reflux tank is related to the liquid level height in the reflux tank, and the pressure in the tank is directly related to the liquid level height.

The specific implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims (6)

1. A virtual simulation platform for simulating a benzene production process, characterized in that it comprises a raw material pump (1-1), a benzene tower top pump (1-2), a first heat exchanger (2-1), a second heat exchanger (2-2), a benzene tower (5), a reboiler, a condenser (7), and a reflux tank (10); wherein the first heat exchanger (2-1) and the second heat exchanger (2-2) are sequentially connected to a pipeline connecting the raw material pump (1-1) and the middle part of the benzene tower (5); an outlet is provided at the top of the benzene tower (5) and is connected to the reflux tank (10) after passing through the condenser (7); the reflux tank (10) is divided into two branches through the control of the benzene tower top pump (1-2): the first branch is used to communicate with the benzene tower (5), and the second branch is used for extraction; an outlet is provided at the bottom of the benzene tower (5): used to flow into the benzene tower (5) after being heated by the reboiler through a pipeline, and used to send out the bottom material. 2. The virtual simulation platform for simulating the benzene production process according to claim 1 is characterized in that the reboiler is arranged in two groups, specifically a first reboiler (4-1) and a second reboiler (4-2), wherein the first reboiler (4-1) controls the flow rate through a first pneumatic valve (3). 3. The virtual simulation platform for simulating the benzene production process according to claim 1, characterized in that the bottom of the benzene tower (5) is provided with a first thermometer (6-1) and the top of the tower is provided with a second thermometer (6-2). 4. The virtual simulation platform for simulating the benzene production process according to claim 1 is characterized in that the reflux tank (10) is provided with a nitrogen input end, an air output end and a waste liquid output end, the nitrogen input end is provided with a second pneumatic valve (8), the air output end is provided with a third pneumatic valve (9), and the waste liquid output end of the benzene tower reflux tank (10) discharges the waste liquid through a gate valve (13). 5. The virtual simulation platform for simulating the benzene production process according to claim 1 is characterized in that the first liquid level meter (12-1) arranged on the reflux tank (10) cooperates with the second flow meter (16-2) to jointly control the valve opening of the fifth pneumatic valve (15) on the second branch. 6. The virtual simulation platform for simulating the benzene production process according to claim 1 is characterized in that a second liquid level gauge (12-2) is provided on the benzene tower (5) for displaying the liquid level of the benzene tower, and cooperates with a sixth pneumatic valve (17) and a flow meter (16-3) to control the liquid level of the benzene tower (5).