Automatic heating system for absorbent of acetylene separation device

Abstract

The present application relates to the technical field of acetylene concentration, and discloses an automatic heating system for an absorbent of an acetylene separation device, which comprises a control system, a data receiving unit and a data sending unit, the data receiving unit is used for receiving liquid-phase temperature, gas-phase temperature and pressure signals of the absorbent in a heating process and sending the signals to the control system, the control system comprises a heating control module and a progress control module, the heating control module is used for controlling a heating rate of the absorbent, and the current heating rate of the absorbent is controlled within a set heating rate range, and the progress control module is used for monitoring a current heating temperature and a heating progress of the absorbent in real time and sending a control value of a next heating cycle to the heating control module according to the heating progress. The present application can solve the problem that it is difficult to accurately control the heating rate of the absorbent in the absorbent heating preparation process before the acetylene separation system is started, and the absorbent is lost and escapes.

Description

Technical Field

[0001] This invention relates to the field of acetylene concentration technology, specifically to an automatic heating system for the absorbent in an acetylene separation device. Background Technology

[0002] In the process of producing acetylene from natural gas or other methane-rich gases in a reaction unit, the reaction yields a mixed gas containing acetylene. This mixed gas primarily contains large amounts of hydrogen, methane, acetylene components, carbon dioxide, C4 or higher compounds, and solid particulate dust. To separate this mixed gas, dust removal equipment is typically used first, followed by an acetylene separation unit employing absorption and desorption methods to separate and purify the acetylene.

[0003] Before the acetylene separator is put into operation, an absorbent regeneration pathway needs to be established. This is because the absorbent is often recycled and transferred into the system after shutdown, containing excess gas and moisture. At this point, the absorbent lacks normal absorption capacity. Establishing a regeneration pathway transforms the absorbent from a high-moisture state at normal temperature and pressure to a high-temperature, negative-pressure regeneration state. This process first requires depressurizing the separation system, then heating the absorbent. This depressurization and heating process evaporates and removes excess moisture and residual gas, enabling the absorbent to function normally. After heating, the mixed gas is introduced into the separator. The soluble gases in the mixed gas are absorbed by the absorption tower, and then the target gas is desorbed using a desorption tower, yielding pure acetylene gas.

[0004] However, the current heating operation of absorbent is mostly controlled manually. After confirming that the vacuum equipment is in operation, the vacuum pumping volume is manually controlled by remote regulating valve. On-site operators slowly open the manual valves before and after the steam heating regulating valve is fully opened, and then switch to remote manual control of the steam heating regulating valve. During the heating process, it is necessary to continuously monitor the absorbent temperature in the system, the gas phase temperature change in the vacuum pumping passage, and the liquid temperature change in the washing tower.

[0005] The above process requires operators to maintain control and monitor for more than 10 hours, and the coordination between indoor and outdoor operators is difficult and the workload is heavy, which can easily lead to operator fatigue and cause absorbent loss. In addition, manual operation makes it difficult to accurately control the heating rate of the absorbent. If the absorbent heats up too quickly, the huge airflow will carry the absorbent out and pollute the environment. If the heating is too slow, the amount of system wash water added will be greater than the amount of water removed, which will affect the function of the absorbent. Moreover, as the temperature reaches 60-90℃, a large amount of accumulated water vapor will evaporate. Liquid water will be continuously added and gaseous water will be continuously output. The huge gas flow rate will also cause absorbent to escape, thus causing environmental incidents. Summary of the Invention

[0006] The present invention aims to provide an automatic heating system for the absorbent in an acetylene separation device, in order to solve the problem of absorbent loss and leakage caused by the difficulty in accurately controlling the heating rate of the absorbent during the preheating preparation process before the start-up of the acetylene separation system.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An automatic heating system for the absorbent in an acetylene separation device includes a control system, a data receiving unit, and a data sending unit. The data receiving unit receives liquid phase temperature, gas phase temperature, and pressure signals during the absorbent heating process and sends these signals to the control system. The control system processes the input detection values ​​and pre-set control values ​​and outputs control signals. The data sending unit sends the control signals to the execution unit in the absorbent heating system. The control system includes a heating control module and a progress control module. The heating control module controls the heating rate of the absorbent, keeping the current heating rate within a set range. The progress control module monitors the current heating temperature and heating progress of the absorbent in real time and sends the control value for the next heating cycle to the heating control module based on the heating progress.

[0009] Furthermore, the progress control module includes a scheduling unit. This unit outputs the control temperature for the next cycle after time t1, based on the current liquid phase temperature TT1 of the absorbent, the set heating rate S1, and the heating evaluation ratio M. This control temperature is used as the preset temperature for the heating control module. The heating control module controls the absorbent heating according to this preset temperature. The formula for calculating the control temperature for the next cycle is as follows:

[0010] The heating evaluation ratio M and the heating period t1 are set as needed. When M = n, the average heating rate S1n in the first n periods is calculated, and the unit of the heating rate is ℃ / h.

[0011] Furthermore, the progress control module also includes a switching unit, which is used to set a switching temperature threshold. When the current liquid phase temperature of the absorbent is greater than or equal to the switching temperature threshold, the switching unit switches the current heating rate of the absorbent and sends the set heating rate after switching to the heating control module. The heating control module controls the current heating rate of the absorbent according to the set heating rate after switching.

[0012] Furthermore, the control system also includes a gas phase temperature auxiliary control module, which is used to assist in adjusting the heating rate of the absorbent and to set an upper limit value for the gas phase temperature. When the current gas phase temperature on the gas phase pipeline is greater than or equal to the upper limit value, the gas phase temperature auxiliary control module sends a control signal to the progress control module. After receiving the signal, the progress control module switches the current heating rate, and the heating rate after switching is lower than the heating rate before switching.

[0013] Furthermore, the control module also includes a vacuum control module, which is used to adjust the vacuum level of the absorbent heating system and control the system vacuum level within a preset vacuum range.

[0014] Furthermore, the control module also includes a water washing flow control module, which is used to adjust the water washing flow of the absorbent heating system according to the temperature of the discharged liquid phase, and set the current temperature of the discharged liquid phase within a preset temperature range.

[0015] Furthermore, the heating control module includes a large-circulation heating control module and a small-circulation heating control module. The large-circulation heating control module is used to control the heating rate of the absorbent in the large-circulation system, and the small-circulation heating control module is used to control the heating rate of the absorbent in the small-circulation system.

[0016] An acetylene separator absorbent heating system is disclosed, which uses an automatic heating system to control the heating process of the absorbent. The system includes a large absorbent circulation loop, a small absorbent circulation loop, a water washing device, and a vacuum device. The gas phase in the large absorbent circulation loop is connected to the small absorbent circulation loop through a gas phase pipeline one. The gas phase in the small absorbent circulation loop is connected to the inlet of the water washing device through a gas phase pipeline two. The outlet of the water washing device is connected to the vacuum device through a gas phase pipeline three.

[0017] Furthermore, the absorbent circulation loop is equipped with a steam heating pipeline for heating the liquid phase absorbent in the absorbent circulation loop. A main regulating valve and a small regulating valve are connected in parallel on the steam heating pipeline. The absorbent circulation loop is also equipped with a sensor for detecting the liquid phase temperature of the absorbent. The sensor is used to send the liquid phase temperature signal in the absorbent circulation loop to the heating control module.

[0018] Furthermore, the absorbent small circulation loop is equipped with a second steam heating pipe for heating the liquid phase absorbent in the absorbent small circulation loop, and a fourth regulating valve for controlling the amount of steam is installed on the second steam heating pipe; the absorbent small circulation loop is also equipped with a second sensor for detecting the liquid phase temperature of the absorbent, and the second sensor is used to send the liquid phase temperature signal in the absorbent small circulation loop to the heating control module.

[0019] Furthermore, the large circulation loop of the absorbent includes an absorption device 2, a desorption device 3, a deep desorption device 4, and an absorption device 2 connected in sequence; the small circulation loop of the absorbent includes an absorption device 1, a desorption device 1, a deep desorption device 2, and an absorption device 1 connected in sequence; the absorption device 1 and the absorption device 2 are connected by pipelines, and the deep desorption device 4 is connected to the deep desorption device 2 through a gas phase pipeline 1.

[0020] Furthermore, the washing equipment is equipped with a drain pipe at the bottom and a water inlet pipe at the top. The drain pipe is equipped with a sensor for detecting the temperature of the discharged liquid phase, and the water inlet pipe is equipped with a water regulating valve for controlling the water flow rate.

[0021] Furthermore, the vacuum equipment is equipped with a vacuum regulating valve on the gas phase pipeline for adjusting the system vacuum level, and the absorbent system is also equipped with a pressure sensor and a temperature sensor for detecting the gas phase temperature on the gas phase pipeline.

[0022] Furthermore, a temporary vacuum regulating pipeline is also installed on the gas phase pipeline of the vacuum equipment, which is used to regulate the load of the vacuum equipment.

[0023] A control method for an automatic heating system of absorbent in an acetylene separator, used to control the automatic heating of absorbent in an acetylene separator absorbent heating system, includes the following steps:

[0024] Step 1: Adjust the system vacuum level;

[0025] Step 2: Control the temperature rise of the absorbent in the large circulation loop;

[0026] Step 3: Control the temperature rise of the absorbent in the absorbent small circulation loop;

[0027] Step 4: Control the water flow rate at the inlet of the washing equipment and the liquid phase temperature at the outlet;

[0028] Step 5: Adjust the heating rate of the absorbent based on the gas phase temperature in the heating system.

[0029] Furthermore, a vacuum control module is used to control the vacuum level in step one. The vacuum control module has a pre-set standard negative pressure range value. The pressure sensor installed on the gas phase pipeline is used as an input unit to send the real-time negative pressure value of the system to the vacuum control module. When the real-time negative pressure value is less than the minimum value of the standard negative pressure range, the vacuum control module controls the vacuum regulating valve to open wider. When the real-time negative pressure value is greater than the maximum value of the standard negative pressure range, the vacuum control module controls the vacuum regulating valve to open narrower.

[0030] Furthermore, a large-circulation heating control module is used to control the temperature rise of the absorbent in the large-circulation loop of the absorbent in step two; sensor one is an input unit used to send the current liquid phase temperature of the absorbent to the large-circulation heating control module in real time. If the current temperature rise is less than the set temperature rise, the large-circulation heating control module controls the steam valve to open wider; if the current temperature rise is greater than the set temperature rise, the large-circulation heating control module controls the steam valve to open narrower.

[0031] Furthermore, in the initial stage of heating, the large circulation heating control module first controls the small regulating valve two to open gradually. After the valve position of the small regulating valve two is fully opened, it then controls the main regulating valve one to open gradually.

[0032] Furthermore, a small-circulation heating control module is used to control the heating temperature of the absorbent in the large-circulation loop of the absorbent in step three. Sensor two serves as a signal input unit, used to send the current liquid phase temperature signal of the absorbent in the small-circulation loop to the small-circulation heating control module. If the current heating temperature is less than the set heating temperature, the small-circulation heating control module controls the regulating valve four to open wider. If the current heating temperature is greater than the set heating temperature, the small-circulation heating control module controls the regulating valve four to open narrower.

[0033] Furthermore, a water washing flow control module is used to control the water washing flow rate at the inlet of the water washing equipment and the liquid phase temperature at the outlet in step five. Sensor three serves as a signal input unit, used to send the current liquid phase temperature at the outlet to the water washing flow control module in real time. The water washing flow control module has a preset discharge liquid phase temperature. If the current liquid phase temperature is less than the preset discharge liquid phase temperature, the water washing flow control module controls the water regulating valve to open slightly. If the current liquid phase temperature is greater than or equal to the preset discharge liquid phase temperature, the water washing flow control module controls the water regulating valve to open wider until the current liquid phase temperature is less than the preset discharge liquid phase temperature.

[0034] Furthermore, if the current liquid phase temperature is less than the preset discharge liquid phase temperature, but when either sensor one or sensor two detects that the liquid phase temperature of the absorbent is greater than or equal to the preset discharge liquid phase temperature, the water washing flow control module adjusts the inlet water flow according to the preset discharge liquid phase temperature.

[0035] Beneficial effects:

[0036] 1. Precise control of absorbent heating process: By setting up an automatic absorbent heating system, the entire heating process of the absorbent is automatically adjusted and monitored. The heating temperature of the next cycle is updated and calculated in real time based on the heating parameters on site, thereby ensuring that the absorbent heats up according to the theoretical heating curve. This solves the existing problem of absorbent loss and environmental pollution caused by excessively rapid or slow heating.

[0037] 2. Reduce steam supply and temperature fluctuations: The amount of absorbent in the large absorbent circulation is large, and the required heat exchange steam supply is also increased. By setting a main regulating valve one and a small regulating valve two in the large circulation loop, and starting the small regulating valve two first and then starting the main regulating valve one during the startup process, the problem of temperature being difficult to stabilize due to drastic fluctuations in steam volume during startup can be solved, and more stable regulation can be achieved.

[0038] 3. Limiting the heating rate by combining gas phase temperature: By setting up an auxiliary control module for gas phase temperature and linking it to the heating rate, a secondary limiting condition for the heating rate is added. On the one hand, this helps to ensure the safe heating of the absorbent, and on the other hand, it facilitates control to achieve a more precise heating rate, further reducing the problem of absorbent escape.

[0039] 4. Simplified operation process and reduced operational difficulty: By automating and integrating control units such as heating steam volume, washing water addition volume, absorbent temperature, gas phase temperature and vacuum pressure, an automatic absorbent heating technology is formed, which solves the problems of time-consuming and labor-intensive absorbent heating process, high operational difficulty and heavy workload for staff. Attached Figure Description

[0040] Figure 1 This is a flowchart of the acetylene separation device in Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the connection structure of the absorbent heating system in the acetylene separation device according to Embodiment 1 of the present invention;

[0042] Figure 3 This refers to the automatic heating system for the absorbent in the acetylene separation device in Example 2;

[0043] Figure 4 This is a schematic diagram of the control system modules in Example 2;

[0044] Figure 5 This is a connection diagram of the control system in Example 3. Detailed Implementation

[0045] The following detailed description illustrates the specific implementation method:

[0046] The reference numerals in the accompanying drawings include: 1. Absorbent large circulation loop; 2. Absorbent small circulation loop; 3. Water washing equipment; 4. Vacuum equipment; 101. Gas phase pipeline 1; 102. Gas phase pipeline 2; 103. Steam pipeline 1; 202. Steam pipeline 2; 301. Main regulating valve 1; 302. Small regulating valve 2; 303. Manual bypass 3; 304. Regulating valve 4; 305. Manual bypass 5; 306. Water regulating valve; 307. Vacuum regulating valve; 41. Temporary vacuum regulating pipeline; 5. Control system; 5. Vacuum control module; 52. Water washing flow control module; 53. Heating control module; 531. Large circulation heating control module; 532. Small circulation heating control module; 54. Progress control module; 541. Switching unit; 542. Scheduling unit; 55. Gas phase temperature auxiliary control module; 6. Data receiving unit; 7. Data sending unit.

[0047] Example 1

[0048] like Figure 1 As shown in the figure, this embodiment provides an acetylene separation device for separating and purifying acetylene mixed gas. The mixed gas is divided into three parts according to its properties: easily soluble and small-volume higher alkynes, soluble and moderate-volume acetylene, and poorly soluble and large-volume tail gas.

[0049] Specifically, the process employs three stages: absorption unit 1, desorption unit 1, and deep desorption unit 2, to separate higher alkynes and acetylene components. During startup, the mixed gas to be separated is introduced into absorption unit 1. In absorption unit 1, a small flow rate of absorbent is used to saturate and absorb the easily soluble higher alkynes. A small amount of acetylene component is initially desorbed and recovered in preliminary desorption unit 1. This acetylene component has low purity and needs to be returned to the mixed gas for further separation. Then, deep desorption unit 2 is used to perform deep and thorough desorption of the absorbent and dissolved higher alkynes, removing the dissolved gas phase to obtain pure higher alkynes. The liquid absorbent is cooled and then introduced back into absorption unit 1 for recycling. This absorbent recycling route is called the "solvent mini-circulation" or "absorbent mini-circulation loop."

[0050] The process employs a second absorption unit, a third desorption unit, and a fourth deep desorption unit to separate acetylene components and tail gas. Specifically, the mixed gas that was not absorbed by the first absorption unit enters the second absorption unit, where a high-flow-rate absorbent absorbs the soluble acetylene components. The undissolved tail gas is discharged from the gas phase pipeline of the second absorption unit, while the dissolved acetylene is discharged from the liquid phase pipeline along with the absorbent to the third desorption unit. In the third desorption unit, preliminary desorption is performed to produce acetylene of higher purity. Then, in the fourth deep desorption unit, thorough deep desorption is performed to remove the dissolved gas phase, yielding high-purity acetylene gas. The absorbent, after being cooled, is reintroduced into the second absorption unit for recycling. This absorbent recycling route is called the "solvent large circulation" or "absorbent large circulation loop."

[0051] However, before the acetylene mixture was introduced into the engine, the absorbent had already been recycled multiple times. The absorbent contained excess gas and moisture exceeding the standard, and the absorbent was in a normal temperature and pressure state. Therefore, it was necessary to preheat and depressurize the absorbent before the engine was started to evaporate and remove the excess moisture and gas in the absorbent, so that the absorbent could have a normal absorption function.

[0052] In summary, this embodiment also provides an acetylene separator absorbent heating system, which aims to transform the absorbent in the acetylene separator from a state of "normal temperature and pressure with high water content" to a state of "having normal absorption function".

[0053] like Figure 2 As shown, the absorbent heating system includes a large absorbent circulation loop 1, a small absorbent circulation loop 2, a water washing device 3, and a vacuum device 4. The gas phase in the large absorbent circulation loop 1 is connected to the small absorbent circulation loop 2 through a gas phase pipeline 101. The gas phase in the small absorbent circulation loop 2 is connected to the inlet of the water washing device 3 through a gas phase pipeline 102. The outlet of the water washing device 3 is connected to the vacuum device 4 through a gas phase pipeline 103.

[0054] In this embodiment, a heat exchanger is used to heat the absorbent, and the heat source of the heat exchanger is steam. Specifically, the absorbent large circulation loop 1 is equipped with a steam heating pipeline 201 for heating the liquid phase absorbent. A main regulating valve 301, a small regulating valve 302, and a manual bypass 303 are connected in parallel on the steam heating pipeline 201. The absorbent large circulation loop 1 is also equipped with a sensor TT1 for detecting the liquid phase temperature of the absorbent. Specifically, sensor TT1 can be installed in the bottom of the deep desorption device 4.

[0055] The absorbent small circulation loop 2 is equipped with a second steam heating pipe 202, which is connected to the main steam pipe via a tee to the first steam heating pipe 201. The second steam heating pipe 202 is equipped with a regulating valve 304 for controlling the amount of steam and a manual bypass 305. Specifically, the absorbent small circulation loop 2 is also equipped with a second sensor (TT10) for detecting the liquid phase temperature of the absorbent. In this embodiment, the second sensor TT10 is installed in the bottom of the deep desorption device 2.

[0056] The washing equipment 3 has a drain pipe at the bottom and a water inlet pipe at the top. A sensor (TT3) for detecting the liquid phase temperature is installed on the drain pipe, and a water regulating valve 306 for controlling the inlet water flow is installed on the water inlet pipe. The vapor phase from the liquid phase evaporation in the large absorbent circulation loop 1 enters the small absorbent circulation loop 2 through gas phase pipeline 101, where it merges with the vapor phase in the small circulation loop and then enters the washing equipment 3 through gas phase pipeline 203. Under the washing action of the washing equipment 3, the water vapor and absorbent in the vapor phase are condensed and cooled into a liquid phase, which is then discharged through the drain pipe of the washing equipment 3 to the subsequent treatment stage. The vapor phase that is not condensed by the washing equipment is extracted by the vacuum equipment 4 through gas phase pipeline 303.

[0057] Vacuum device 4 is equipped with a vacuum regulating valve 307 on the gas phase pipeline for adjusting the vacuum level in the absorbent system. The gas phase pipeline of the absorbent system is also equipped with a pressure sensor and a temperature sensor for detecting the gas phase temperature. Specifically, in actual use, temperature sensors can be installed on gas phase pipeline 101 and gas phase pipeline 202, and pressure sensors can be installed on gas phase pipeline 303 (not shown in the figure).

[0058] In this embodiment, a temporary vacuum regulating pipeline 41 is also provided on the gas phase pipeline of the vacuum device 4. The temporary vacuum regulating pipeline 41 is used to regulate the load of the vacuum device 4. For example, by filling a certain amount of inert gas into the temporary vacuum regulating pipeline 41, a portion of the load of the vacuum device 4 is occupied, so that the remaining load meets the system requirements. The above scheme makes the vacuum device 4 more stable and reliable, and reduces the risk of interlocking shutdown and maintenance costs in actual use.

[0059] Example 2

[0060] This embodiment provides an automatic heating system for the absorbent in an acetylene separation device, used to automatically control the automatic heating process of the absorbent in an acetylene separation device as disclosed in Embodiment 1, so as to ensure accurate heating of the absorbent and solve the problem of absorbent leakage. It is worth noting that the automatic heating control system in this embodiment is not limited to the acetylene separation device disclosed in Embodiment 1, but can also be used in other acetylene separation systems or similar systems that require heating control of the absorbent.

[0061] like Figure 3As shown, an automatic heating system for the absorbent in an acetylene separation device includes a control system 5, a data receiving unit 6, and a data sending unit 7. The data receiving unit 6 receives detection signal values ​​such as gas phase pressure, gas phase temperature, and liquid phase temperature detected by various sensors in the absorbent heating system, and sends these signals to the control system 5. The control system 5 processes the input detection values ​​and the preset control values ​​in the system and outputs control signals. The data sending unit 7 sends these control signals to various regulating valves in the absorbent heating system. The regulating valves operate according to the received control signals, thereby ensuring that the detection values ​​and control values ​​remain consistent.

[0062] like Figure 4 As shown, the control system 5 includes a vacuum control module 51, a heating control module 53, a water washing flow control module 52, and a progress control module 54.

[0063] The vacuum control module 51 is used to adjust the vacuum level of the system according to the received gas phase pressure and the preset control pressure in the system, and control the vacuum level of the system within the preset vacuum range; to create a stable negative pressure environment for the absorbent heating process, to ensure the controllability of pressure and the ease of operation during the heating process, and to reduce the workload of operators.

[0064] The heating control module 53 is used to adjust the opening of the steam valve according to the current liquid phase temperature of the received absorbent and the preset control temperature in the system, thereby adjusting the heating rate of the absorbent and controlling the current heating rate of the absorbent within the set heating rate range. This improves the accuracy of control, ensures that the absorbent heats up stably according to the theoretical heating curve, and avoids the absorbent heating up too quickly or too slowly. In particular, it avoids the problem of absorbent escaping due to the generation of a huge airflow caused by the absorbent heating up too quickly.

[0065] Specifically, the heating control module 53 includes a large-circulation heating control module 531 and a small-circulation heating control module 532. The large-circulation heating control module 531 is used to control the heating rate of the absorbent in the large-circulation system, and the small-circulation heating control module 532 is used to control the heating rate of the absorbent in the small-circulation system.

[0066] The water washing flow control module 52 is used to adjust the inlet water flow of the water washing device 3 in real time according to the current discharge liquid phase temperature and the preset control temperature in the system, so that the discharge liquid phase temperature of the water washing device 3 is kept within the preset temperature range. This achieves precise control of the inlet water flow of the water washing device 3, avoiding the problem that excessive water washing volume will affect the function of the absorbent, increase the discharge volume of the water washing device 3, and increase the difficulty of subsequent treatment, as well as avoiding the problem that insufficient water washing volume will cause the gas phase absorbent to escape due to untimely cooling and condensation. By setting up the water washing device 3 and the water washing flow control module 52, it is beneficial to limit the activity range of the absorbent and reduce the risk of absorbent escape from the back end.

[0067] The progress control module 54 is used to monitor the current heating temperature and heating progress of the absorbent, and to send new control values ​​to the heating control module 53 according to the heating progress. It includes a switching unit 541 and a scheduling unit 542. The switching unit 541 stores a preset switching temperature threshold value, and is used to determine whether the absorbent should continue to heat at the current heating rate in the next heating cycle according to the current liquid phase temperature of the absorbent.

[0068] When the current liquid phase temperature of the absorbent is greater than or equal to the critical value of the switching temperature, the switching unit 541 switches the current heating rate of the absorbent and sends the switched set heating rate to the heating control module 53. The heating control module 53 uses the received set heating rate as the new control value to control the current heating rate of the absorbent. Otherwise, the switching unit 541 does not send a new control value to the heating control module 53, and the heating control module 53 continues to control the heating of the absorbent according to the current heating rate.

[0069] The scheduling unit 542 calculates and outputs the control temperature for the next cycle after heating cycle t1 based on the current liquid phase temperature TT1 of the absorbent, combined with the set heating rate S1 and the heating evaluation ratio M. This control temperature is then sent to the heating control module 53 as its preset temperature. The heating control module 53 outputs a control steam valve opening signal according to this preset temperature to control the heating temperature of the absorbent, ensuring that the current liquid phase temperature of the absorbent matches the preset temperature. The formula for calculating the control temperature for the next cycle is as follows:

[0070]

[0071] The heating evaluation ratio M and the heating period t1 can be set as needed. For example, assuming M = n, the average heating rate S1n in the first n periods is calculated. That is, S1n is the average heating rate in the first n t1 periods, and the unit of heating rate is ℃ / h.

[0072] Using Formula 1 above can achieve the following technical effects:

[0073] 1. Dynamic adjustment: By considering the average heating rate S1n of the previous n cycles, the control temperature TT1' of the next cycle is dynamically adjusted, which helps to ensure that the actual heating rate can gradually approach the set heating rate S1.

[0074] 2. Precise control: It can more precisely control the heating process of the absorbent, avoiding heating too fast or too slow, thereby reducing the risk of absorbent leakage and improving the safety and efficiency of operation.

[0075] 3. Feedback mechanism: Adjustment factor in the formula A feedback mechanism was introduced, enabling the system to dynamically adjust the control strategy based on the actual temperature rise, ensuring the stability and reliability of the temperature rise process.

[0076] In this embodiment, the control system 5 also includes a gas phase temperature auxiliary control module 55. The gas phase temperature auxiliary control module 55 is used to assist in adjusting the heating rate of the absorbent. The gas phase temperature auxiliary control module 55 stores the upper limit value of the gas phase temperature. When the temperature sensor on the gas phase pipeline detects that the current gas phase temperature is greater than or equal to the upper limit value of the gas phase temperature, it indicates that the current heating rate is relatively fast. At this time, the gas phase temperature auxiliary control module 55 sends a control signal to the progress control module 54. After receiving the signal, the progress control module 54 switches the current heating rate and heats up according to the preset minimum heating rate, thereby reducing the current heating rate.

[0077] Example 3

[0078] This embodiment also provides a control method for an automatic heating system of the absorbent in an acetylene separation device, used to control the automatic heating process of the absorbent; specifically, this embodiment uses NMP (a mixture of nitrogen-methylpyrrolidone with a water content of about 2.5%) as the system absorbent for detailed explanation. The heating rate of NMP includes two stages: when the liquid phase temperature of NMP is <90℃, the heating rate is 3-5℃ / h; when the liquid phase temperature of NMP is ≥90℃, the heating rate is 10℃ / h.

[0079] like Figure 5 As shown, its control method is as follows:

[0080] Step 1: Introduce the absorbent to facilitate material flow.

[0081] The stored absorbent at room temperature and pressure is introduced into the large / small circulation loop to complete the material flow. The moisture content of the absorbent before heating is sampled and analyzed, and the liquid level of each device in the large / small circulation loop is counted.

[0082] Step 2: Adjust the system vacuum level to ensure that it remains within the preset vacuum range throughout the heating process.

[0083] First, check whether the pressure value detected by the pressure sensor on the gas phase pipeline in the system is lower than the maximum limit of the absorbent regeneration environment pressure. If not, the operator should check the gas phase path. If so, start the automatic heating system and use the vacuum control module 51 to control the vacuum degree of the system. The vacuum control module 51 has a standard negative pressure range value preset in it.

[0084] The pressure sensor installed on the gas phase pipeline is a signal input unit used to send the real-time negative pressure value of the system to the vacuum control module 51. When the real-time negative pressure value is less than the minimum value of the standard negative pressure range, the vacuum control module 51 controls the vacuum regulating valve 307 to open wider. When the real-time negative pressure value is greater than the maximum value of the standard negative pressure range, the vacuum control module 51 controls the vacuum regulating valve 307 to open narrower.

[0085] Specifically, in this embodiment, the vacuum control module 51 sets the standard negative pressure control value to 20 kPa. When the input signal from the field pressure sensor is 18 kPa, the vacuum control module 51 compares the control value and the real-time value, calculates the signal that increases by 2 kPa, and converts it into an instrument signal output to control the opening of the vacuum regulating valve 307, so that the field pressure sensor detects a value of 20 kPa.

[0086] Step 3: Adjusting the temperature rise of the absorbent in the large circulation loop: The large circulation heating control module 531 is used to control the temperature rise of the absorbent. The sensor TT1 set in the absorbent heating system is used as a signal input unit to send the current liquid phase temperature of the absorbent to the large circulation heating control module 531 in real time. If the current temperature rise TT1 is less than the set temperature rise, the large circulation heating control module 531 controls the steam valve to open wider. If the current temperature rise TT1 is greater than the set temperature rise, the large circulation heating control module 531 controls the steam valve to open narrower.

[0087] In this embodiment, due to the large volume of the absorbent solvent in the large circulation (it is recommended to use a digital representation of this large volume), the steam consumption varies greatly before and after heating, resulting in large steam fluctuations during the heating start-up process, making it difficult to stabilize the temperature. To solve this problem, the large circulation heating control module 531 also includes a temporary temperature control module, which is used to control the valve opening of the small regulating valve 302. In the initial stage of heating, the temporary temperature control module controls the small regulating valve 302 to open gradually. When the small regulating valve 302 is fully open, it feeds back a signal to the large circulation heating control module 531 to control the main regulating valve 301 to open gradually. In this embodiment, the optimal flow ratio between the main regulating valve 301 and the small regulating valve 302 is 36:1.

[0088] During the heating process of the large-circulation absorbent, the progress control module 54 monitors the heating progress in real time and adjusts it according to the following control method:

[0089] When TT1 < the switching temperature critical value T4, the scheduling unit outputs the control temperature of the next cycle after time t1 according to Formula 1, combined with the real-time liquid phase temperature TT1, the set heating rate S1, and the heating evaluation ratio M1, and uses this control temperature as the cascade control parameter of the large-cycle heating control module.

[0090] When TT1≥T4, the scheduling unit outputs the control temperature of the next cycle after time t1 according to Formula 1, combined with the real-time liquid phase temperature TT1, the set heating rate S2, and the heating evaluation ratio M1, and uses this control temperature as the cascade control parameter of the large-cycle heating control module.

[0091] For example, in this embodiment, the temperature critical point T4 is set to 90°C, S1 is the set heating rate before 90°C, for example, 4°C / h, and S2 is the set heating rate after 90°C, for example, 10°C / h.

[0092] When TT1 ≥ termination temperature T5, T5 is used as the control value of the large-cycle heating control module 531, and the small regulating valve 302 is closed. Specifically, the steam small regulating valve 302 decreases its position by 20% for each cycle t1 until it is completely closed, completing the large-cycle heating. After the heating is completed, the main regulating valve 301 is in the open state to maintain the temperature of the absorbent. Specifically, in this embodiment, T5 is 116℃.

[0093] Step 4: Adjusting the temperature rise of the absorbent in the small circulation loop: The small circulation heating control module 532 is used to control the temperature rise of the absorbent. Sensor 2 TT10 is used as a signal input unit to send the current liquid phase temperature signal of the absorbent in the small circulation loop to the small circulation heating control module 532. If the current temperature rise TT10 is less than the set temperature rise, the small circulation heating control module 532 controls the regulating valve 4 304 to open wider. If the current temperature rise TT10 is greater than the set temperature rise, the small circulation heating control module 532 controls the regulating valve 4 304 to open narrower.

[0094] The heating temperature can be set manually or calculated and output by the scheduling unit 542 in the progress control module 54; this embodiment prefers the latter. Specifically, the small-cycle progress adjustment control process is as follows:

[0095] When TT10 < the switching temperature threshold T40, the scheduling unit 542 outputs the control temperature of the next cycle after time t10 according to Formula 1, combined with the real-time liquid phase temperature TT10, the set heating rate S10, and the heating evaluation ratio M10, and uses this control temperature as the cascade control parameter of the small cycle heating control module 532.

[0096] When TT10≥T40, the scheduling unit 542 outputs the control temperature of the next cycle after time t10 according to Formula 1, combined with the real-time liquid phase temperature TT10, the set heating rate S20, and the heating evaluation ratio M10, and uses this control temperature as the cascade control parameter of the small cycle heating control module 532.

[0097] Specifically, in this embodiment, the temperature switching threshold T40 in the small loop is set to 90℃, S10 is the set heating rate before 90℃, set to 4℃ / h, and S20 is the set heating rate after 90℃, set to 10℃ / h.

[0098] When TT10 ≥ termination temperature T50, T50 is used as the control value of the small-cycle heating control module 532, and the regulating valve 304 is closed to complete the small-cycle heating. Specifically, in this embodiment, T50 is 118℃.

[0099] Step 5: Adjust the water flow rate at the inlet of the washing equipment to control the liquid phase temperature at the outlet of the washing equipment 3 within the set temperature range. It is worth mentioning that when the large circulation and small circulation start to heat up, the water flow control module 52 starts simultaneously.

[0100] The water washing flow control module 52 controls the water washing flow rate at the inlet of the water washing equipment 3 and the liquid phase temperature at the outlet. The sensor TT3 serves as a signal input unit, which sends the current liquid phase temperature at the outlet to the water washing flow control module 52 in real time. The water washing flow control module 52 is preset with a preset discharge liquid phase temperature. When TT3 < preset discharge liquid phase temperature, the water washing flow control module 52 controls the water regulating valve 306 to open slightly. When TT3 ≥ preset discharge liquid phase temperature, the water washing flow control module 52 controls the water regulating valve 306 to open wider, until the current TT3 < preset discharge liquid phase temperature.

[0101] Specifically, when TT3 < preset discharge liquid phase temperature, but either TT1 or TT10 sensor detects that the absorbent liquid phase temperature is ≥ preset discharge liquid phase temperature, the water washing flow control module 52 can adjust the inlet water flow according to the preset discharge liquid phase temperature. This is because, in actual use, when the current discharge liquid phase temperature detected by TT3 is < preset discharge liquid phase temperature, in order to reduce the downstream discharge volume, the water washing flow control module 52 will control the water regulating valve 306 to close slightly. However, at this time, the liquid phase temperature in the large / small circulation absorbent has already reached 60℃, and the temperature rise becomes even faster. If the water regulating valve 306 is closed slightly, the gas phase in the water washing equipment 3 will not have enough time to cool down and will escape.

[0102] Specifically, in this embodiment, the preset discharge liquid phase temperature is 60℃. When sensor TT3 detects that the current liquid phase temperature at the drain outlet reaches 58℃, or when either sensor TT1 or sensor TT10 exceeds 60℃, the water washing flow control module 52 cascades the water regulating valve 306 according to 60℃. The adjusted inlet water flow rate is the minimum control flow rate, and it is maintained at no less than this minimum control flow rate. Specifically, in this embodiment, it is no less than 1.5m. 3 / h.

[0103] Step 6: Based on the gas phase temperature in the heating system, adjust the heating rate of the absorbent to further ensure that the absorbent is heated at the optimal heating rate and achieve more precise control.

[0104] The heating rate of the absorbent is adjusted by a gas phase temperature auxiliary control module 55. The gas phase temperature auxiliary control module 55 stores the upper limit value of the gas phase temperature. When the temperature sensor on the gas phase pipeline detects that the current gas phase temperature is greater than or equal to the upper limit value of the gas phase temperature, it indicates that the current heating rate is relatively fast. At this time, the current heating rate can be reduced or the water inlet flow rate of the washing equipment can be increased. In this embodiment, the former is preferred.

[0105] Specifically, in this embodiment, sensor TT4 is installed on gas phase pipeline 101 and sensor TT5 is installed on gas phase pipeline 102. Sensor TT4 is used to detect the temperature of the large circulation gas phase, and sensor TT5 is used to detect the temperature of the small circulation gas phase. In this embodiment, the upper limit of the gas phase temperature is 82°C. When either TT4 or TT5 is greater than 82°C, the temperature is increased at 70-80% of the heating rate S1 or S10. For example, the original 4°C / h is adjusted to 3°C / h to slow down the current heating rate.

[0106] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An automatic heating system for the absorbent in an acetylene separation device, characterized in that: It includes a control system, a data receiving unit, and a data sending unit. The data receiving unit is used to receive the liquid phase temperature, gas phase temperature, and pressure signals during the absorbent heating process and send the signals to the control system. The control system processes the input detection values ​​and the preset control values ​​in the system and outputs control signals. The data sending unit is used to send the control signals to the execution unit in the absorbent heating system. The control system includes a heating control module and a progress control module. The heating control module is used to control the heating rate of the absorbent and keep the current heating rate of the absorbent within the set heating rate range. The progress control module is used to monitor the current heating temperature and heating progress of the absorbent in real time and send the control value of the next heating cycle to the heating control module according to the heating progress.

2. The automatic heating system for the absorbent in an acetylene separation device according to claim 1, characterized in that: The progress control module includes a scheduling unit. The scheduling unit outputs the control temperature for the next cycle after time t1, based on the current liquid phase temperature TT1 of the absorbent, the set heating rate S1, and the heating evaluation ratio M. This control temperature is used as the preset temperature for the heating control module. The heating control module controls the absorbent heating according to this preset temperature. The calculation formula for the control temperature of the next cycle is as follows: The heating evaluation ratio M and the heating period t1 are set as needed. When M = n, the average heating rate S1n in the first n periods is calculated, and the unit of the heating rate is ℃ / h.

3. The automatic heating system for the absorbent in an acetylene separation device according to claim 2, characterized in that: The progress control module also includes a switching unit, which is used to set a switching temperature threshold. When the current liquid phase temperature of the absorbent is greater than or equal to the switching temperature threshold, the switching unit switches the current heating rate of the absorbent and sends the set heating rate after switching to the heating control module. The heating control module controls the current heating rate of the absorbent according to the set heating rate after switching.

4. The automatic heating system for the absorbent in an acetylene separation device according to claim 3, characterized in that: The control system also includes a gas phase temperature auxiliary control module, which is used to assist in adjusting the heating rate of the absorbent and to set an upper limit value for the gas phase temperature. When the current gas phase temperature on the gas phase pipeline is greater than or equal to the upper limit value, the gas phase temperature auxiliary control module sends a control signal to the progress control module. After receiving the signal, the progress control module switches the current heating rate, and the heating rate after switching is lower than the heating rate before switching.

5. An automatic heating system for the absorbent in an acetylene separation device according to any one of claims 1-4, characterized in that: The control system also includes a vacuum control module, which is used to adjust the vacuum level of the absorbent heating system and control the system vacuum level within a preset vacuum range.

6. The automatic heating system for the absorbent in an acetylene separation device according to claim 5, characterized in that: The control system also includes a water washing flow control module, which is used to adjust the water washing flow of the absorbent heating system according to the temperature of the discharged liquid phase, and to set the current temperature of the discharged liquid phase within a preset temperature range.

7. A heating system for an acetylene separator absorbent, comprising controlling the heating process of the absorbent using an automatic heating system for an acetylene separator absorbent as described in claim 6, characterized in that: It includes a large absorbent circulation loop, a small absorbent circulation loop, a water washing device, and a vacuum device. The gas phase in the large absorbent circulation loop is connected to the small absorbent circulation loop through gas phase pipeline one. The gas phase in the small absorbent circulation loop is connected to the air inlet of the water washing device through gas phase pipeline two. The air outlet of the water washing device is connected to the vacuum device through gas phase pipeline three.

8. The acetylene separation device absorbent system according to claim 7, characterized in that: The absorbent circulation loop is equipped with a steam heating pipeline for heating the liquid phase absorbent in the absorbent circulation loop. A main regulating valve and a small regulating valve are connected in parallel on the steam heating pipeline. The absorbent circulation loop is also equipped with a sensor for detecting the liquid phase temperature of the absorbent. The sensor is used to send the liquid phase temperature signal in the absorbent circulation loop to the heating control module.

9. A control method for an automatic heating system of an acetylene separator absorbent, used to control the automatic heating of the absorbent in the acetylene separator absorbent heating system as described in claim 8, characterized in that, Includes the following steps: Step 1: Adjust the system vacuum level; Step 2: Control the temperature rise of the absorbent in the large circulation loop; Step 3: Control the temperature rise of the absorbent in the absorbent small circulation loop; Step 4: Control the water flow rate at the inlet of the washing equipment and the liquid phase temperature at the outlet; Step 5: Adjust the heating rate of the absorbent based on the gas phase temperature in the heating system.

10. The control method for an automatic heating system of the absorbent in an acetylene separation device according to claim 9, characterized in that, In the initial stage of heating in step two, the large circulation heating control module first controls the small regulating valve two to open gradually. After the valve position of the small regulating valve two is fully opened, the main regulating valve one is then controlled to open gradually.

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