A control system for ultra-low carbon mixed butanol separation

Abstract

The utility model discloses a kind of control systems of ultra-low carbon mixed butyl aldehyde separation, it is characterized by, including: series first separation unit, second separation unit;First separation column in the first separation unit is provided with feed inlet receiving mixed butyl aldehyde raw material on side wall, the top of the first separation column is provided with gas outlet and is connected with the second reboiler of second separation unit by gas outlet pipeline, so that the gas phase stream generated by the first separation column can provide heat for second separation unit, form two-unit heat coupling structure;Second separation column side wall in the second separation unit is provided with import, and is connected to the outlet of the second reboiler by conveying pipeline, receives the condensate obtained by the second reboiler;The top of the second separation column is provided with discharge port for outputting isobutyraldehyde, and bottom is provided with discharge port for outputting separated n-butyl aldehyde. By designing two separation units series and heat coupling, let first separation column gas phase power for second separation unit, reduce additional heat source consumption, while separating mixed butyl aldehyde step by step, both reduce energy consumption, and guarantee isobutyraldehyde, n-butyl aldehyde separation effect and output purity.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment technology, specifically to a control system for the separation of ultra-low carbon mixed butyraldehyde. Background Technology

[0002] In the chemical production field, butanol and octanol are important organic chemical raw materials, and the separation of butyraldehyde in their production process has always been a challenge for energy consumption control. With the intensification of the global energy crisis and the advancement of carbon neutrality goals, the chemical industry faces unprecedented pressure to save energy and reduce consumption. Specifically, in the butanol and octanol production chain, the n-butyraldehyde (boiling point 74℃) and isobutyraldehyde (boiling point 64℃) produced by the catalytic reaction of propylene and syngas have similar boiling points. Traditional separation processes require multi-stage distillation to achieve separation, resulting in huge steam consumption in the reboiler of the separation tower, accounting for 30% to 40% of the total energy consumption of the butanol and octanol plant, becoming a key bottleneck restricting the economic efficiency of production.

[0003] Although differential pressure thermal coupling distillation schemes have emerged in the existing technology, which control the temperature by adjusting the steam flow rate of the high-pressure column reboiler and the liquid level in the shell side of the low-pressure column reboiler in an attempt to solve the problem of insufficient operational flexibility caused by excessive heat exchange area, this scheme still has limitations: on the one hand, its thermal coupling structure is limited to the utilization of inter-column pressure difference and does not fully explore the waste heat value of the gaseous stream; on the other hand, temperature control depends on steam flow regulation and does not form a multi-parameter collaborative optimization mechanism, resulting in limited actual energy-saving effect.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] The purpose of this application is to provide a control system for the separation of ultra-low carbon mixed butyraldehyde. This system is designed with two separation units connected in series and thermally coupled, so that the gas phase of the first separation tower supplies energy to the second separation unit, reducing the consumption of additional heat sources. At the same time, it separates mixed butyraldehyde in steps, which not only reduces energy consumption, but also ensures the separation effect and output purity of isobutyraldehyde and n-butyraldehyde.

[0006] To achieve the above objectives, this application provides the following technical solution: A control system for separating ultra-low carbon mixed butyraldehyde includes: a first separation unit and a second separation unit connected in series; The first separation tower in the first separation unit has a feed inlet on its side wall to receive mixed butyraldehyde raw material. The top of the first separation tower has a gas outlet connected to the second reboiler of the second separation unit via a gas outlet pipeline, so that the gaseous stream generated by the first separation tower can provide heat to the second separation unit, forming a thermally coupled structure between the two units. The second separation tower in the second separation unit has an inlet on its side wall, which is connected to the outlet of the second reboiler via a conveying pipeline to receive the condensate obtained from the second reboiler. The top of the second separation tower has a discharge outlet for outputting isobutyraldehyde, and the bottom has a discharge outlet for outputting separated n-butyraldehyde.

[0007] Furthermore, it also includes a control unit, which is connected to the temperature transmitter, pressure transmitter, level transmitter and flow transmitter on the first separation unit and the second separation unit respectively, and is also connected to the control valve on each pipeline. The control unit receives the detection signals from the transmitters and outputs control commands to the control valves.

[0008] Furthermore, the first separation unit also includes a first reboiler, the heat source input end of the first reboiler is connected to a low-pressure steam supply pipeline, the input end of the first reboiler is connected to the first separation tower, and the first reboiler is equipped with the liquid level transmitter. By changing the heat exchange area of ​​the first reboiler, the temperature of the first separation tower can be controlled.

[0009] Furthermore, the downstream end of the gas outlet pipe connected to the top outlet of the first separation tower is also branched to the first reflux tank in the first separation unit. The top of the first reflux tank is provided with a gas discharge pipe, which is connected to the tail gas condenser. A pressure transmitter is also provided at the top of the first reflux tank, and a control valve is provided on the gas discharge pipe.

[0010] Furthermore, the bottom of the first reflux tank is provided with a bottom outlet, which is divided by a three-way pipe. One branch is connected back to the top of the first separation tower through the reflux pipeline, and the other branch is connected to the side wall inlet of the second separation tower through the output pipeline. The reflux pipeline is equipped with a flow transmitter and a control valve. The control valve is adjusted by the control unit to regulate the reflux flow rate at the top of the first separation tower.

[0011] Furthermore, a butyraldehyde discharge pipeline is installed at the bottom of the first separation tower, and a flow transmitter and control valve are installed on the butyraldehyde discharge pipeline. A level transmitter is also installed in the bottom of the first separation tower to achieve stable control of the liquid level in the first separation tower.

[0012] Furthermore, the input end of the second reboiler is connected to the bottom of the second separation tower, and the output end of the second reboiler is connected back to the second separation tower. The second reboiler is connected to the level transmitter, and the level transmitter is connected to the control unit. The control unit adjusts the control valve on the input pipeline of the second reboiler based on the detection signal of the level transmitter to change the heat exchange area.

[0013] Furthermore, the top outlet of the second separation tower is connected to the second reflux tank in the second separation unit. A second gas discharge pipeline is installed at the top of the second reflux tank, and the control valve is installed on the second gas discharge pipeline. The pressure transmitter is installed at the top of the second reflux tank. A discharge pipeline is installed at the bottom of the second reflux tank. The discharge pipeline is divided into two paths: one path goes to the top of the second separation tower through a return pipeline, and the other path serves as the isobutyraldehyde collection pipeline. A flow transmitter and a control valve are installed on the return pipeline. The control unit adjusts the control valve based on the detection signal from the flow transmitter to achieve precise control of the reflux flow rate at the top of the second separation tower.

[0014] Furthermore, a n-butyraldehyde (N-butyraldehyde) outlet pipeline is installed at the bottom of the second separation tower. The N-butyraldehyde outlet pipeline is equipped with the flow transmitter and control valve, and the second separation tower is equipped with the level transmitter. The control unit determines the set value of the N-butyraldehyde outlet flow rate based on the detection signal of the level transmitter, and stably delivers the separated N-butyraldehyde to the subsequent process section.

[0015] Furthermore, the temperature transmitter is installed at the bottom of the first and second separation towers. The control unit obtains the real-time temperature of the separation towers through the temperature transmitter and compares it with the preset temperature value to achieve precise control of the bottom temperature of the two separation towers.

[0016] Compared with the prior art, the beneficial effects achieved by this application are as follows: The control system of this application, through the series design and thermal coupling structure of the first and second separation units, fully utilizes the gaseous stream at the top of the first separation tower to provide heat to the second separation unit, reducing the consumption of external heat sources and effectively lowering energy consumption in the mixed butyraldehyde separation process, allowing the system to meet the requirements of low carbon and energy saving. Simultaneously, the control unit of this system is linked with the temperature, pressure, liquid level, and flow transmitters and pipeline control valves of each separation unit, realizing both single-loop and series control scenarios. It can collect key parameters in real time and accurately adjust the operating status of related equipment, ensuring the initial separation effect of the first separation tower on the mixed butyraldehyde, and achieving deep separation of n-butyraldehyde and isobutyraldehyde through the second separation tower, improving the efficiency of the entire separation process and the quality stability of n- and isobutyraldehyde. Furthermore, the setting of reflux tanks and reboilers in each separation unit, along with corresponding control mechanisms, further optimizes the operating structure of the control system, avoiding the problem of decreased separation effect due to parameter fluctuations, and comprehensively improving the economy and reliability of the mixed butyraldehyde separation process. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the overall structure of a control system for the separation of ultra-low carbon mixed butyraldehyde in this embodiment; Figure 2 This is a schematic diagram of the overall instrumentation of the first unit in this embodiment; Figure 3 This is a schematic diagram of the overall instrumentation of the second unit in this embodiment.

[0018] Figure label: 1-First separation tower, 2-Second separation tower, 3-Inlet, 4-Outlet, 5-Outlet pipeline, 6-Transfer pipeline, 7-First reboiler, 8-First reflux tank, 9-Second reboiler, 10-Second reflux tank, 11-Tail gas condenser, 12-Gas discharge pipeline, 13-Reflux pipeline, 14-Butyraldehyde discharge pipeline, 15-Second gas discharge pipeline, 16-First reflux pump, 17-Second reflux pump, 18-Discharge pipe, 19-Reconnection pipeline, 20-Isobutyraldehyde extraction pipeline, 21-Butyraldehyde extraction pipeline. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of the present invention, not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0020] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] To more clearly illustrate the technical solutions of this invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0023] Reference Figure 1-3 As shown, this embodiment of a control system for the separation of ultra-low carbon mixed butyraldehyde includes a first separation unit and a second separation unit connected in series, as well as a control unit. The first separation unit, as a preliminary separation device for the mixed butyraldehyde, performs pretreatment and partial component separation, laying the foundation for the subsequent deep separation in the second separation unit. The second separation unit then completes the final separation of n-butyraldehyde and isobutyraldehyde. This system is used in butyraldehyde production processes to achieve efficient and low-energy separation of n-butyraldehyde and isobutyraldehyde. Through a combination of structural optimization and intelligent control, this system significantly reduces the energy consumption of traditional separation processes and improves the overall economic and environmental benefits of the process.

[0024] Specifically, the key equipment in the first separation unit is the first separation tower 1, which has a feed inlet 3 on its side wall. The outer end of the feed inlet 3 is connected to the upstream mixing and output device (not shown in the figure) through a raw material conveying pipeline, which can stably receive mixed butyraldehyde raw material. The mixed butyraldehyde raw material enters the middle section of the first separation tower 1 through the feed pipeline, where preliminary gas-liquid separation takes place. Due to the difference in boiling points between n-butyraldehyde and isobutyraldehyde, different component distributions are formed at different heights in the tower. Among them, n-butyraldehyde, which has a higher boiling point, tends to sink downwards and remain in the bottom of the tower, and is collected through the n-butyraldehyde discharge pipeline 14 at the bottom of the first separation tower 1, while the lighter component containing more isobutyraldehyde is discharged in gas phase form from the gas outlet 4 at the top.

[0025] To maintain the separation conditions within the first separation tower 1 and ensure the continuous and stable operation of the separation process, the first separation unit is also equipped with a first reboiler 7. The heat source input end of the first reboiler 7 is connected to a low-pressure steam supply pipeline. By introducing low-pressure steam, heat is provided to the mixed butyraldehyde raw material in the bottom of the first separation tower 1, causing the mixed butyraldehyde raw material to evaporate and form rising steam, which achieves sufficient heat and mass exchange with the descending liquid within the tower. Simultaneously, a level transmitter (LT-103) is installed on the first reboiler 7. This level transmitter (LT-103) is connected to a control unit. The control unit receives the level signal detected by the level transmitter within the first reboiler 7 and adjusts the control valve (LV-103) on the relevant pipeline of the first reboiler 7, changing the heat exchange area within the first reboiler 7. This achieves precise temperature control of the first separation tower 1, ensuring that the temperature within the tower is maintained within a suitable separation range, guaranteeing separation efficiency while avoiding energy waste caused by excessively high temperatures.

[0026] The gas outlet 4 at the top of the first separation tower 1 is connected to the second reboiler 9 in the second separation unit via an outlet pipeline 5. This is the key to achieving the thermal coupling structure of the two units in this application. The gaseous stream generated by the first separation tower 1 enters the second reboiler 9 through the outlet pipeline 5, providing the required reboiling heat to the second separation tower 2 in the second separation unit. After releasing heat in the second reboiler 9, the gaseous stream condenses into a liquid, forming condensate. This design fully utilizes the sensible and latent heat of the gas at the top of the first separation tower, significantly reducing the dependence of the second separation tower on external heat sources (such as steam), thereby achieving a significant reduction in the overall energy consumption of the system. This significant reduction in the energy consumption of the entire system achieves the goal of energy saving, which is also an important manifestation of the ultra-low carbon energy-saving characteristics of the system in this embodiment.

[0027] The downstream end of the outlet pipeline 5, i.e., the outlet end of the second reboiler 9, is also branched to the first reflux tank 8 in the first separation unit, and the condensate enters the first reflux tank 8. A gas discharge pipeline 12 is provided at the top of the first reflux tank 8, which is connected to the tail gas condenser 11. This pipeline is used to transport the non-condensable gas that has not been condensed in the first reflux tank 8 to the tail gas condenser 11 for treatment, so as to avoid the accumulation of non-condensable gas affecting the stability of system pressure, and at the same time reduce waste and environmental pollution.

[0028] A pressure transmitter (PT-101) is installed at the top of the first reflux tank 8. The pressure transmitter (PT-101) transmits the detected pressure signal in the first reflux tank 8 to the control unit. The control unit adjusts the opening of the control valve (PV-101) according to the preset pressure range to achieve stable control of the pressure at the top of the first separation tower 1. The bottom of the first reflux tank 8 is provided with a bottom outlet. The bottom outlet is divided into two branches by a three-way pipe. One branch is connected to the top of the first separation tower through the reflux pipeline 13 and the first reflux pump 16 to send part of the condensate back to the first separation tower 1 as reflux liquid. The reflux liquid flows from top to bottom in the tower and fully contacts the rising steam to further improve the separation effect. The other branch is connected to the side wall inlet of the second separation tower through the output pipeline to transport another part of the condensate to the second separation tower 2 for deep separation. A flow transmitter (FT-101) and a control valve (FV-101) are installed on the reflux line 13. The flow transmitter (FT-101) detects the flow rate of the reflux liquid in real time and transmits the signal to the control unit. The control unit adjusts the opening of the control valve (FV-101) according to the separation status of the first separation tower to achieve precise control of the reflux flow rate at the top of the first separation tower, and to control the liquid level in the bottom of the first separation tower 1, thereby stabilizing the separation effect.

[0029] The bottom of the first separation tower 1 is equipped with a n-butyraldehyde discharge pipeline 14, which is used to transport the n-butyraldehyde initially separated in the tower bottom to the subsequent process section. A flow transmitter (FT-102) and a control valve (FV-102) are installed on the n-butyraldehyde discharge pipeline 14, and a level transmitter (LT-101) is installed in the tower bottom of the first separation tower. The level transmitter (LT-101) transmits the detected tower bottom liquid level signal to the control unit. The control unit determines the n-butyraldehyde discharge flow rate set value according to the liquid level, and adjusts the opening of the control valve (FV-102) in combination with the actual flow signal detected by the flow transmitter (FT-102) to achieve stable control of the liquid level of the first separation tower. This avoids the tower bottom liquid level from being too high and affecting the separation process, and also prevents the liquid level from being too low and causing equipment damage, while ensuring that n-butyraldehyde can be output stably.

[0030] The core equipment of the second separation unit is the second separation tower 2, whose side wall inlet is connected to the condensate via a conveying pipe 6. After entering the second separation tower 2, the condensate undergoes further separation within the tower. Through finer gas-liquid exchange, isobutyraldehyde and the remaining n-butyraldehyde are completely separated. The second separation unit is also equipped with a second reboiler 9. The input end of the second reboiler 9 is connected to the bottom of the second separation tower, and the output end of the second reboiler 9 is connected back to the second separation tower, forming a material circulation. As mentioned earlier, the heat source for the second reboiler 9 comes from the gaseous stream at the top of the first separation tower. This design fully utilizes waste heat and reduces energy consumption.

[0031] The top outlet of the second separation tower 2 is connected to the second reflux tank 10 in the second separation unit. The gaseous stream generated at the top of the tower enters the second reflux tank 10 after passing through the condenser. A second gas discharge pipeline 15 is installed at the top of the second reflux tank 10 to discharge non-condensable gases. A discharge valve (PV-201) is installed on the second gas discharge pipeline 15, and a pressure transmitter (PT-201) is installed at the top of the second reflux tank. The pressure transmitter (PT-201) transmits the detected pressure signal to the control unit. The control unit adjusts the opening of the discharge valve (PV-201) to achieve stable pressure control of the second separation tower 2. A discharge pipe 18 is installed at the bottom of the second reflux tank 10. This discharge pipeline is divided into two paths: one path goes through a return pipeline 19 and the second reflux pump 17 to the top of the second separation tower, serving as reflux liquid returned to the tower to improve the separation effect; the other path serves as the isobutyraldehyde collection pipeline 20, used to output isobutyraldehyde products that meet the purity standards. A flow transmitter (FT-201) and a control valve (FV-201) are installed on the return pipeline. The control unit adjusts the opening of the control valve (FV-201) based on the signal detected by the flow transmitter (FT-201), so as to achieve precise control of the return flow at the top of the second separation tower 2 and the control of the bottom liquid level, ensuring the stability of the operation inside the tower and the purity of the isobutyraldehyde product.

[0032] The bottom of the reboiler of the second separation tower 2 is equipped with a butyraldehyde (n-butyraldehyde) collection pipeline 21, which is used to transport the high-purity n-butyraldehyde obtained after deep separation to the subsequent process. The n-butyraldehyde collection pipeline 21 is equipped with a flow transmitter (FT-202) and a control valve (FV-202) to achieve stable control of the liquid level in the reboiler of the second separation tower 2, ensuring that n-butyraldehyde can be collected stably.

[0033] To achieve efficient operation of the series separation unit and thermally coupled structure in this embodiment, and to ensure that key parameters such as temperature, pressure, and liquid level remain stable within the optimal range during the separation of mixed butyraldehyde, relying solely on the static structural design of the equipment is far from sufficient; dynamic control of the entire system's operating status is also required.

[0034] Meanwhile, in this system, both the first separation tower 1 and the second separation tower 2 are equipped with high-efficiency packing layers or tower plates. The high-efficiency packing layers are corrugated packing or wire mesh packing, and the tower plates are floating valve tower plates or sieve tower plates to increase the gas-liquid contact area, improve the separation efficiency of n-butyraldehyde and isobutyraldehyde, thereby reducing energy consumption in the separation process, shortening the separation time, and improving the system's processing capacity.

[0035] Specifically, the operation process of the control system in this embodiment is as follows: The system's control process begins with the core parameter of the first separation unit—the reboiler temperature. This is the foundation of the separation process. A temperature transmitter (TT-101) continuously monitors the reboiler temperature and transmits the signal to a temperature controller (TIC-101). TIC-101 compares the measured value with the setpoint. If a deviation occurs, its output signal does not directly operate a valve but is transmitted as a setpoint to another controller—the level controller (LIC-103), thus forming a cascade control loop. LIC-103 receives the signal from the level transmitter (LT-103) and adjusts the liquid level by regulating the opening of the discharge valve (LV-103). This liquid level directly determines the condensation heat exchange area of ​​the steam in the first reboiler 7. Through this cascade control, the system can effectively overcome the interference of steam pressure fluctuations, strictly stabilizing the reboiler temperature within the required range, providing the most critical heat guarantee for the initial separation of n-butyraldehyde and isobutyraldehyde.

[0036] In addition to maintaining a stable temperature, stable liquid level in the column reboiler is equally crucial. A level transmitter (LT-101) monitors the reboiler level and sends the signal to a level controller (LIC-101). LIC-101 also employs a cascade control strategy, using its output signal as the setpoint for the flow controller (FIC-102). FIC-102 then adjusts the opening of the control valve (FV-102) based on the actual n-butyraldehyde discharge flow rate detected by the flow transmitter (FT-102). When the reboiler level is too high, the valve opening increases, accelerating the n-butyraldehyde discharge rate and bringing the level back to normal; conversely, the valve closes to reduce discharge. This control loop ensures stable material balance in the reboiler, preventing accidents such as flooding or cavitation.

[0037] The pressure at the top of the first separation tower is another critical parameter that requires strict control. A pressure transmitter (PT-101) detects the tower top pressure, and a pressure controller (PIC-101) directly regulates the material control valve (PV-101) leading to the first reflux tank 8 via a single loop. If the pressure rises, PIC-101 increases its opening, accelerating the outflow of gaseous material, thus lowering the pressure; if the pressure is too low, it closes the valve to accumulate pressure. Stable pressure is crucial for maintaining a constant boiling point of the mixture and ensuring consistent separation performance.

[0038] The vapor phase from the top of the column, after being condensed in the reboiler, enters the first reflux tank 8. The pressure in this tank is managed by a split-range control system. A pressure transmitter (PT-102) sends a signal to a controller (PIC-102), which, through regulating a control valve (PV-102), releases non-condensable gases from the tank, thereby maintaining the pressure at the set value and ensuring the smooth progress of the condensation process. The liquid level in the first reflux tank 8 is controlled by another cascade loop: the level controller (LIC-102), based on the signal from the level transmitter (LT-102), outputs a value that serves as the setpoint for the flow controller (FIC-103). The FIC-103, through regulating a control valve (FV-103), controls the discharge flow rate, thereby maintaining a stable liquid level. The liquid pumped from the first return tank 8 has its return flow rate regulated by a single-loop control system: the flow transmitter (FT-101) detects the flow rate on the return line 13, and the flow controller (FIC-101) ensures that the return ratio is always at the required value by adjusting the control valve (FV-101).

[0039] The energy-saving thermal coupling control of this system is reflected in the temperature control of the second separation unit. The second separation tower 2 no longer requires an external steam heat source; its heat comes entirely from the gas phase at the top of the first separation tower. This control is achieved through a sophisticated cascade loop: the temperature transmitter (TT-201) at the bottom of the second separation tower 2 sends a signal to the temperature controller (TIC-201), and the output of TIC-201 becomes the setpoint for the level controller (LIC-203). LIC-203 regulates the control valve (LV-203) from the top of the first separation tower by controlling the level of the second reboiler 9. If the temperature at the bottom of the second separation tower 2 is too low, TIC-201 will issue a command to lower the level of the second reboiler 9, and LIC-203 will then increase the opening of LV-203, allowing more high-temperature gas phase to enter, increasing the heat exchange area and heating intensity, thereby raising the temperature. This process perfectly realizes the direct, on-demand transfer of energy from the first separation tower 1 to the second separation tower 2, greatly reducing the steam consumption of the entire system.

[0040] The other controls for the second separation tower 2 are similar to, but independent of, those for the first separation tower 1: the bottom liquid level is controlled in a cascade manner: LIC-201 controls the liquid level as the primary control, and FIC-202 controls the n-butyraldehyde discharge flow rate as the secondary control, adjusting the bottom control valve (FV-202) to stabilize it; the top pressure is stabilized by adjusting the top control valve (PV-201) of the second reflux tank 10 through the split-range control PIC-201; the top reflux flow rate is controlled by a single loop: FIC-201 adjusts FV-201 according to the detection value of FT-201 to ensure the purity of the isobutyraldehyde product.

[0041] Through the structural design and control method of the control system described in this embodiment, the ultra-low carbon mixed butyraldehyde separation control system of this utility model can achieve significant energy-saving effects. On the one hand, the thermal coupling structure that utilizes the gaseous stream from the top of the first separation tower to provide heat to the second separation unit effectively recovers waste heat, reduces external energy consumption, and lowers the overall energy consumption of the system, meeting the requirements of low-carbon and environmental protection. On the other hand, the application of the intelligent control unit can accurately regulate each separation parameter, avoiding the problems of increased energy consumption and decreased separation effect caused by parameter fluctuations, thus improving the operating efficiency of the system. Simultaneously, the two-stage separation unit design achieves stepwise separation of mixed butyraldehyde, improving separation accuracy and ensuring the purity of isobutyraldehyde and n-butyraldehyde products, meeting the requirements of subsequent production processes. Furthermore, the reasonable configuration and linkage control of various devices in the system improve the stability and reliability of the entire separation process. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control system for the separation of ultra-low carbon mixed butyraldehyde, characterized in that, include: The first separation unit and the second separation unit are connected in series; The first separation tower in the first separation unit has a feed inlet on its side wall to receive mixed butyraldehyde raw material. The top of the first separation tower has a gas outlet connected to the second reboiler of the second separation unit via a gas outlet pipeline, so that the gaseous stream generated by the first separation tower can provide heat to the second separation unit, forming a thermally coupled structure between the two units. The second separation tower in the second separation unit has an inlet on its side wall, which is connected to the outlet of the second reboiler via a conveying pipeline to receive the condensate obtained from the second reboiler. The top of the second separation tower has a discharge outlet for outputting isobutyraldehyde, and the bottom has a discharge outlet for outputting separated n-butyraldehyde.

2. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 1, characterized in that, It also includes a control unit, which is connected to the temperature transmitter, pressure transmitter, level transmitter and flow transmitter on the first separation unit and the second separation unit respectively, and is also connected to the control valve on each pipeline. The control unit receives the detection signals from the transmitter and outputs control commands to the control valve.

3. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 2, characterized in that, The first separation unit further includes a first reboiler. The heat source input end of the first reboiler is connected to a low-pressure steam supply pipeline. The input end of the first reboiler is connected to the first separation tower. The first reboiler is equipped with the liquid level transmitter. By changing the heat exchange area of ​​the first reboiler, the temperature of the first separation tower can be controlled.

4. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 2, characterized in that, The downstream end of the gas outlet pipe connected to the top outlet of the first separation tower is also branched to the first reflux tank in the first separation unit. A gas discharge pipe is provided at the top of the first reflux tank, and the gas discharge pipe is connected to the tail gas condenser. A pressure transmitter is also provided at the top of the first reflux tank, and a control valve is provided on the gas discharge pipe.

5. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 4, characterized in that, The bottom of the first reflux tank is provided with a bottom outlet. The bottom outlet is divided by a three-way pipe. One branch is connected back to the top of the first separation tower through a reflux pipeline, and the other branch is connected to the side wall inlet of the second separation tower through the output pipeline. The reflux pipeline is equipped with a flow transmitter and a control valve. The control valve is adjusted by the control unit to regulate the reflux flow rate at the top of the first separation tower.

6. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 2, characterized in that, A butyraldehyde discharge pipeline is installed at the bottom of the first separation tower. The flow transmitter and control valve are installed on the butyraldehyde discharge pipeline. A level transmitter is installed in the bottom of the first separation tower to achieve stable control of the liquid level of the first separation tower.

7. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 2, characterized in that, The input end of the second reboiler is connected to the bottom of the second separation tower, and the output end of the second reboiler is connected back to the second separation tower. The second reboiler is connected to the level transmitter, and the level transmitter is connected to the control unit. The control unit adjusts the control valve on the input pipeline of the second reboiler based on the detection signal of the level transmitter to change the heat exchange area.

8. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 7, characterized in that, The top outlet of the second separation tower is connected to the second reflux tank in the second separation unit. A second gas discharge pipeline is installed at the top of the second reflux tank, and the control valve is installed on the second gas discharge pipeline. The pressure transmitter is installed at the top of the second reflux tank. A discharge pipeline is installed at the bottom of the second reflux tank. The discharge pipeline is divided into two paths: one path goes to the top of the second separation tower through a return pipeline, and the other path serves as the isobutyraldehyde collection pipeline. A flow transmitter and a control valve are installed on the return pipeline. The control unit adjusts the control valve based on the detection signal from the flow transmitter to achieve precise control of the reflux flow rate at the top of the second separation tower.

9. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 8, characterized in that, The bottom of the second separation tower is equipped with a n-butyraldehyde outflow pipeline, and the n-butyraldehyde outflow pipeline is equipped with the flow transmitter and control valve. The second separation tower is also equipped with a level transmitter. The control unit determines the n-butyraldehyde outflow set value based on the detection signal of the level transmitter, and stably delivers the separated n-butyraldehyde to the subsequent process section.

10. The control system for ultra-low carbon mixed butyraldehyde separation according to claim 2, characterized in that, The temperature transmitter is installed at the bottom of the first and second separation towers. The control unit obtains the real-time temperature of the separation towers through the temperature transmitter and compares it with the preset temperature value to achieve precise control of the bottom temperature of the two separation towers.

Images