Extraction feeding system and control method thereof

Abstract

The invention relates to the technical field of aromatic hydrocarbon device extraction units, in particular to an extraction feeding system and a control method thereof.The extraction feeding system comprises a material conveying pump, an extraction raw material tank, an extraction raw material pump, a water-cooling cooler, a heating heat exchanger, an extraction tower, a tank inlet line, a tank outlet line, a raw material pump outlet line, a crossover line and a tank bypass line; an inlet of the material conveying pump is connected with the feeding line; one end of the tank inlet line is connected to an outlet of the material conveying pump, the other end of the tank inlet line is connected to an inlet of the extraction raw material tank, and a second valve and the water cooler are sequentially arranged on the tank inlet line. The device can effectively solve the problem of energy waste in the technical process, ensures the flow and temperature of materials entering an extraction tower, controls the feeding flow to be stable, and ensures that the materials enter a rectifying tower at the temperature of 100 DEG C or above.

Description

Technical Field

[0001] The present invention relates to the technical field of the extraction unit of an aromatic hydrocarbon plant, and particularly relates to an extraction feed system and a control method thereof. Background Art

[0002] Extraction, also known as liquid-liquid extraction, is a method of separating a liquid mixture by utilizing the difference in solubility of each component in a certain solvent. Aromatic hydrocarbon extraction is a process of separating aromatic hydrocarbons from hydrocarbon substances by the method of liquid-liquid extraction. Like operations such as distillation and adsorption, extraction belongs to the physical separation method.

[0003] For the traditional extraction feed system, the material at 80°C is cooled to 50°C by a water-cooled heat exchanger and then enters the extraction raw material tank (the temperature of the tank is required to be lower than 50°C). Then it is pumped and heated to 100°C by a heating heat exchanger and enters the rectification column. Since the feed flow rate of the extraction column is required to be stable, but the existing process has limitations. The material is first cooled and then heated to 100°C and enters the rectification column. This process will consume a large amount of energy, affect the production efficiency, and cannot ensure the stability of the feed flow rate of the extraction column. Summary of the Invention

[0004] In view of the defects of the prior art, the present invention provides an extraction feed system and a control method thereof, which can effectively solve the problem of energy consumption waste in the process, and ensure the flow rate and temperature of the material entering the extraction column, control the stable feed flow rate, and ensure that the material enters the rectification column at a temperature above 100°C.

[0005] To achieve the above object, the technical solution provided by the present invention is an extraction feed system, which includes a material transfer pump, an extraction raw material tank, an extraction raw material pump, a water-cooled cooler, a heating heat exchanger, an extraction tower, a tank inlet line, a tank outlet line, a raw material pump outlet line, a cross line and a tank side line. The inlet of the material transfer pump is connected to the feed line; one end of the tank inlet line is connected to the outlet of the material transfer pump, and the other end is connected to the inlet of the extraction raw material tank. A second valve and the water-cooled cooler are sequentially arranged on the tank inlet line; one end of the tank outlet line is connected to the first outlet of the extraction raw material tank, and the other end is connected to the inlet of the extraction raw material pump; one end of the raw material pump outlet line is connected to the outlet of the extraction raw material pump, and the other end is connected to the inlet of the extraction tower. A second flow control meter, a third valve, a first flow control meter and the heating heat exchanger are sequentially arranged on the raw material pump outlet line. The second flow control meter is electrically connected to the raw material pump outlet line, and the first flow control meter is electrically connected to the raw material pump outlet line. The raw material pump outlet line electrically controls the third valve through the first flow control meter; one end of the cross line is connected to the tank inlet line, and the other end is connected to the raw material pump outlet line. A first valve is arranged on the cross line. The first joint of the cross line and the tank inlet line is located upstream of the second valve, and the second joint of the cross line and the raw material pump outlet line is located downstream of the third valve. The first flow control meter is used to monitor the flow rate downstream of the second joint; one end of the tank side line is connected to the second outlet of the extraction raw material tank, and the other end is connected to the raw material pump outlet line. A fourth valve is arranged on the tank side line. The third joint of the tank side line and the raw material pump outlet line is located upstream of the third valve. The second flow control meter is arranged upstream of the third joint. The raw material pump outlet line electrically controls the fourth valve through the second flow control meter. The second flow control meter is used to monitor the flow rate upstream of the third joint.

[0006] Further, the pressure of the feed line is 0.03 MPa, the material temperature in the feed line is 70°C - 80°C, and the flow rate is 66 t / h - 86 t / h.

[0007] Further, the material flow rate in the feed line is 76 t / h.

[0008] Further, the pressure of the tank inlet line is 0.2 MPa, the material temperature in the tank inlet line is 50°C, and the flow rate is 0 - 86 t / h. The pressure of the tank inlet line and the cross line is 0.2 MPa, and the material temperature in the tank inlet line and the cross line is 80°C, and the flow rate is 0 - 86 t / h.

[0009] Further, the pressure of the water-cooled cooler is 0.18 MPa, the material temperature at the outlet of the water-cooled cooler is 50°C, and the flow rate is 0 - 86 t / h.

[0010] Furthermore, the pressure of the raw material pump outlet line is 0.2 MPa, the temperature of the material in the raw material pump outlet line is 50 °C, and the flow rate is 20 - 100 t / h.

[0011] Furthermore, the material pressure downstream of the second joint is 75 °C and the flow rate is 76 t / h. Using the control method of the above-mentioned extraction feed system, the steps include S100. Open the first valve, the second valve, the third valve, the fourth valve, and the fifth valve. The second valve is opened slightly to save energy on the water-cooled cooling water. S200. Set a stable flow rate value on the first flow control meter and the lowest flow rate value on the second flow control meter. S300. Feed the material in the feed line. When the outlet flow rate of the material transfer pump increases, the second flow control meter electrically connects to control the fourth valve to open widely to keep the flow rate downstream of the second joint stable. S400. When the outlet flow rate of the material transfer pump decreases, the first flow control meter electrically connects to control the third valve to open widely, and the second flow control meter electrically connects to control the fourth valve to open slightly to keep the flow rate downstream of the second joint stable. S500. When the outlet flow rate of the material transfer pump decreases again, the first flow control meter electrically connects to control the third valve to open slightly, and the second flow control meter controls the fourth valve to the lowest flow rate value to keep the flow rate downstream of the second joint stable.

[0012] The beneficial effects of the present invention: It can effectively solve the problem of energy consumption waste in the process, and ensure the flow rate and temperature of the material entering the extraction column, control the stable feed flow rate, ensure that it enters the rectification column above 100 °C, and achieve a double energy-saving effect through the water-cooled cooler and the heating heat exchanger, enabling the extraction feed system to operate continuously, stably, and well for a long time. Description of the Drawings

[0013] Figure 1 It is the process flow chart of the present invention; In the figure: 100, material transfer pump; 110, feed line, 200, extraction raw material tank, 300, extraction raw material pump, 400, extraction column, 500, tank inlet line; 510, second valve; 520, water-cooled cooler, 600, tank outlet line, 700, tank bypass line; 710, fourth valve, 800, raw material pump outlet line; 810, second flow control meter; 820, third valve; 830, first flow control meter; 840, fifth valve; 850, heating heat exchanger, 900, cross line; 910, first valve, A, Connector 1; B, Connector 2; C, Connector 3. Detailed implementation mode

[0014] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe in detail the specific implementation mode of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0015] Such as Figure 1As shown, an extraction feed system in an embodiment of the present invention is shown, including a material transfer pump 100, an extraction raw material tank 200, an extraction raw material pump 300, a water-cooled cooler 520, a heating heat exchanger 850, an extraction tower 400, a tank inlet line 500, a tank outlet line 600, a raw material pump outlet line 800, a cross line 900, and a tank bypass line 700. The inlet of the material transfer pump 100 is connected to the feed line 110; one end of the tank inlet line 500 is connected to the outlet of the material transfer pump 100, and the other end is connected to the inlet of the extraction raw material tank 200. A second valve 510 and a water-cooled cooler 520 are sequentially arranged on the tank inlet line 500; one end of the tank outlet line 600 is connected to the first outlet of the extraction raw material tank 200, and the other end is connected to the inlet of the extraction raw material pump 300; one end of the raw material pump outlet line 800 is connected to the outlet of the extraction raw material pump 300, and the other end is connected to the inlet of the extraction tower 400. A second flow control meter 810, a third valve 820, a first flow control meter 830, and a heating heat exchanger 850 are sequentially arranged on the raw material pump outlet line 800. The second flow control meter 810 is electrically connected to the raw material pump outlet line 800, and the first flow control meter 830 is electrically connected to the raw material pump outlet line 800. The raw material pump outlet line 800 electrically controls the third valve 820 through the first flow control meter 830; one end of the cross line 900 is connected to the tank inlet line 500, and the other end is connected to the raw material pump outlet line 800. A first valve 910 is arranged on the cross line 900. The first joint A between the cross line 900 and the tank inlet line 500 is located upstream of the second valve 510, and the second joint B between the cross line 900 and the raw material pump outlet line 800 is located downstream of the third valve 820. The first flow control meter 830 is used to monitor the flow rate downstream of the second joint B; one end of the tank bypass line 700 is connected to the second outlet of the extraction raw material tank 200, and the other end is connected to the raw material pump outlet line 800. A fourth valve 710 is arranged on the tank bypass line 700. The third joint C between the tank bypass line 700 and the raw material pump outlet line 800 is located upstream of the third valve 820. The second flow control meter 810 is arranged upstream of the third joint C. The raw material pump outlet line 800 electrically controls the fourth valve 710 through the second flow control meter 810. The second flow control meter 810 is used to monitor the flow rate upstream of the third joint C.

[0016] It should be noted that when the third valve 820 is closed slightly, the operation of the second flow control meter 810 will decrease, preventing the risk of pump cavitation. The second flow control meter 810 is set with a minimum flow rate, and the fourth valve 710 will be automatically opened to control and protect the pump; In an embodiment, a fifth valve 840 is further arranged on the raw material pump outlet line 800, and the fifth valve 840 is arranged between the heating heat exchanger 850 and the first flow control meter 830.

[0017] In an embodiment, the pressure of the feed line 110 is 0.03 MPa.

[0018] In one embodiment, the pressure of the tank inlet line 500 is 0.2 MPa, and the materials in the tank inlet line 500 and the crossover line 900 are at 80 °C and 76 t / h.

[0019] In one embodiment, the materials at the outlet of the water-cooled cooler 520 are at 50 °C and 76 t / h.

[0020] In one embodiment, the materials in the outlet line of the raw material pump are at 50 °C and 76 t / h.

[0021] In one embodiment, the materials downstream of the second joint B are at 75 °C.

[0022] In one embodiment, the pressure of the heating heat exchanger 850 is 2.2 Mpa, and the materials at the outlet of the heating heat exchanger 850 are at 100 °C.

[0023] See the attached Figure 1 As shown, using the control method of the above extraction feed system, the steps include Step S100: Open the first valve 910, the second valve 510, the third valve 820, the fourth valve 710, and the fifth valve 840. The second valve 510 is opened slightly to save energy on the water-cooled cooling water.

[0024] It should be noted that when the first flow control meter 830 is put into use and the stable value is set, when the material supplied by the material transfer pump 100 changes, after adjustment through the first valve 910, in order to keep the flow stable, the first flow control meter 830 will remotely transmit the third valve 820 to open wider or close smaller to ensure the flow is stable.

[0025] Step S200: Set the stable flow value for the first flow control meter 830 and set the minimum flow value for the second flow control meter 810.

[0026] Step S300: When the material comes in on the feed line 110, when the outlet flow of the material transfer pump 100 increases, the second flow control meter 810 electrically connects to control the fourth valve 710 to open wider to keep the flow stable downstream of the second joint B.

[0027] Step S400: When the outlet flow of the material transfer pump 100 decreases, the first flow control meter 830 electrically connects to control the third valve 820 to open wider, and the second flow control meter 810 electrically connects to control the fourth valve 710 to open smaller to keep the flow stable downstream of the second joint B.

[0028] Step S500: When the outlet flow of the material transfer pump 100 decreases again, the first flow control meter 830 electrically connects to control the third valve 820 to open smaller, and the second flow control meter 810 controls the fourth valve 710 to open to the minimum flow value to keep the flow stable downstream of the second joint B.

[0029] The fourth valve 710 in the above control method has two functions. One is to balance the flow rate of the first flow control meter 830, and the other is to prevent the extraction feed pump 300 from being damaged after the third valve 820 is closed slightly.

[0030] A control method for an extraction feed system, which operates in the extraction feed system as described above; when it is normally put into use, the first valve 910, the second valve 510, the third valve 820, the fourth valve 710, and the fifth valve 840 are opened. The second valve 510 is opened slightly, and the feed line 110 of the water-cooled cooler 520 (energy-saving 1) is set to 0.03 MPa with a small opening. The material comes in through the feed line 110, and the material is transported to the tank inlet line 500 and the cross-line 900 through the material transfer pump 100. The pressure inside the material transfer pump 100 is 0.2 MPa. After passing through the material transfer pump 100, the material is at 80 °C and 76 t / h. The material in the tank inlet line 500 is cooled to 50 °C through the water-cooled cooler 520, and the temperature in the cross-line 900 remains unchanged and is closed slightly. The 50 °C material in the tank inlet line 500 is transported to the raw material pump outlet line 800 through the extraction raw material tank 200, the extraction raw material pump, and the bypass line 700 beside the tank, and meets with the 80 °C material in the cross-line 900, so that the material transported to the heating heat exchanger 850 is raised from 50 °C to 75 °C. Then, through the heating heat exchanger 850, the heat source is set to 2.2 MPa steam (energy-saving 2), and the material is heated to 100 °C (it must be above 100 °C to enter the extraction tower 400). Then, the stable flow rate is controlled through the first flow control meter 830. Therefore, the material entering the extraction tower 400 achieves a stable flow rate above 100 °C, solving the problem of heat supply for extraction, achieving the double energy-saving effect, and saving cooling water and heating steam.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0032] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plural" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0033] In the present invention, unless otherwise clearly specified or defined, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified or defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature. It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it may be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation.

Claims

1. Extraction and feeding system, characterized by: include Material delivery pump, the inlet of which is connected to the feed line; Extraction tank, Extraction pump, Water-cooled chiller, Heating heat exchanger, Extraction tower, A tank inlet line, one end of which is connected to the outlet of the material delivery pump and the other end of which is connected to the inlet of the extraction raw material tank, and the tank inlet line is provided with a second valve and the water-cooled cooler in sequence; A tank outlet line, one end of which is connected to an outlet of the extraction raw material tank, and the other end is connected to an inlet of the extraction raw material pump; A raw material pump outlet line, one end of which is connected to the outlet of the extraction raw material pump, and the other end of which is connected to the inlet of the extraction tower. The raw material pump outlet line is provided with a second flow control meter, a third valve, a first flow control meter and the heating heat exchanger in sequence. The second flow control meter is electrically connected to the raw material pump outlet line, and the first flow control meter is electrically connected to the raw material pump outlet line. The raw material pump outlet line is electrically connected to control the third valve through the first flow control meter. A jumper line, one end of which is connected to the tank inlet line, and the other end of which is connected to the raw material pump outlet line, a first valve is arranged on the jumper line, a first joint between the jumper line and the tank inlet line is located upstream of the second valve, a second joint between the jumper line and the raw material pump outlet line is located downstream of the third valve, and the first flow control meter is used to monitor the flow downstream of the second joint; as well as A tank bypass route has one end connected to outlet two of the extraction raw material tank and the other end connected to the raw material pump outlet line. A fourth valve is arranged on the tank bypass route. A third joint between the tank bypass route and the raw material pump outlet line is located upstream of the third valve. The second flow control meter is arranged upstream of the third joint. The raw material pump outlet line electrically controls the fourth valve through the second flow control meter. The second flow control meter is used to monitor the flow upstream of the third joint.

2. The extraction and feeding system according to claim 1, characterized in that: The raw material pump outlet line is also provided with a fifth valve, and the fifth valve is provided between the heating heat exchanger and the first flow control meter.

3. The extraction and feeding system according to claim 1, characterized in that: The pressure of the feed line is 0.03 MPa, the material temperature in the feed line is 70° C.-80° C., and the flow rate is 66 t / h-86 t / h.

4. The extraction and feeding system according to claim 1, characterized in that: The material flow rate in the feed line is 76t / h.

5. The extraction and feeding system according to claim 1, characterized in that: The pressure of the tank inlet line is 0.2MPa, the temperature of the material in the tank inlet line is 50°C, the flow rate is 0-86t / h, the pressure of the tank inlet line and the cross line is 0.2MPa, the temperature of the material in the tank inlet line and the cross line is 80°C, and the flow rate is 0-86t / h.

6. The extraction and feeding system according to claim 1, characterized in that: The pressure of the water-cooled cooler is 0.18 MPa, the material temperature at the outlet of the water-cooled cooler is 50°C, and the flow rate is 0-86t / h.

7. The extraction and feeding system according to claim 1, characterized in that: The outlet line pressure of the raw material pump is 0.2MPa, the material temperature in the outlet line of the raw material pump is 50°C, and the flow rate is 20-100t / h.

8. The extraction and feeding system according to claim 1, characterized in that: The material pressure downstream of the second joint is 75°C and the flow rate is 76 t / h.

9. The extraction and feeding system according to claim 1, characterized in that: The feed temperature of the heating heat exchanger is 75°C, the flow rate is 76t / h, the pressure of the heating heat exchanger is 0.18MPa, the material temperature at the outlet of the heating heat exchanger is 100°C, the flow rate is 76t / h, and the heat source of the tube bundle of the heating heat exchanger is 2.2MPa steam.

10. The control method of the extraction and feeding system according to claims 1 to 8 is characterized in that: Steps include S100, open the first valve, the second valve, the third valve, the fourth valve and the fifth valve, open the second valve slightly, and turn down the water-cooled cooling water to save energy; S200, the first flow control table sets a stable flow value, and the second flow control table sets a minimum flow value; S300, when the material is fed into the feed line, when the outlet flow of the material delivery pump increases, the second flow control meter electrically controls the fourth valve to open widely to keep the flow downstream of the second connector stable; S400, when the outlet flow of the material delivery pump decreases, the first flow control meter controls the third valve to open widely, and the second flow control meter controls the fourth valve to open slightly, so as to keep the flow downstream of the second connector stable; S500, when the outlet flow of the material delivery pump decreases again, the first flow control meter electrically controls the third valve to a small opening, and the second flow control meter controls the fourth valve to a minimum flow value to keep the flow downstream of the second connector stable.

Images