Automatic control method and system for a drying machine

Abstract

The application provides an automatic control method and system of a dryer, the method comprising: performing pressure relief inside the dryer to a first preset pressure value, filling the dryer with regenerated gas to a preset pressure filling pressure value; performing low-temperature purging inside the dryer according to a preset low-temperature purging time, performing constant-temperature purging inside the dryer according to a preset constant-temperature purging time and a preset constant-temperature purging temperature; increasing the temperature inside the dryer to a preset temperature increasing temperature and maintaining the temperature for a set time, and decreasing the temperature inside the dryer to a preset temperature; and the system comprises a data acquisition module, a processing module and a control module. The application performs low-temperature purging before high-temperature purging and high-temperature heating, so that the hydrocarbon impurities in the bed layer can be removed from the dryer, thereby preventing coking in the equipment caused by direct high-temperature heating, and affecting the service life of the dryer.

Description

Technical Field

[0001] This invention relates to the field of chemical reaction control technology, and more specifically, to an automatic control method and system for a dryer. Background Technology

[0002] In the chemical industry, if the product gas separated from the product separation device contains moisture, it can cause it to freeze or form hydrates in the downstream cryogenic system, clogging the downstream cryogenic system and damaging the cryogenic equipment.

[0003] Therefore, two devices are usually set up, consisting of two product gas dryers. Each dryer has two desiccant beds. When the moisture reaches the sampling probe, it indicates that the main bed section is exhausted, and the dryer should be switched immediately.

[0004] In existing technologies, the process of switching a dryer from operation to regeneration and back to operation is mostly done manually based on operator experience. The control of time and parameters depends entirely on the operator's experience, which wastes manpower and has relatively low overall efficiency. Moreover, the purging process in the regeneration process of existing technologies is generally carried out by high-temperature purging, which will affect the service life of the dryer to some extent. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the purpose of this invention is to provide an automatic control method and system for a dryer.

[0006] According to the present invention, an automatic control method for a dryer is provided, the dryer comprising at least two dryers, and the automatic control method comprises the following steps:

[0007] Acquire the sequential start-up status data for each dryer, and control the dryers based on the sequential start-up status data. The sequential start-up status data includes at least one dryer in drying operation mode and at least one dryer in regeneration operation mode or standby mode. The operation process of the dryer in regeneration operation mode includes:

[0008] The internal pressure of the dryer is released to the first preset pressure value, and regeneration gas is introduced into the dryer to the preset charging pressure value.

[0009] The inside of the dryer is purged at a low temperature for a preset low temperature purging time. After the low temperature purging is completed, the temperature is gradually increased until the purging temperature reaches the preset constant temperature purging temperature. The inside of the dryer is then purged at a constant temperature according to the preset constant temperature purging time and preset constant temperature purging temperature.

[0010] The internal temperature of the dryer is raised to a preset temperature and maintained at that temperature for a set time. After maintaining the temperature for the set time, the internal temperature of the dryer is lowered to the preset temperature.

[0011] The internal pressure of the dryer is depressurized again to the second preset pressure value, and the regenerated dryer is set to the drying working state. The dryer in the drying working state is then switched to the regeneration working state.

[0012] Optionally, setting the regenerated dryer to a drying state and then switching the dryer from the drying state to a regeneration state further includes:

[0013] The regenerated dryer and the dryer in drying operation are connected in parallel, and the regenerated dryer is in low flow rate operation.

[0014] After the dryer has been in parallel operation for a preset time in the drying state, the regenerated dryer is set to the drying state, the dryer in the drying state stops working, and the operation is switched to the regeneration state.

[0015] Optionally, after depressurizing the inside of the dryer to the second preset pressure value, and before setting the regenerated dryer to the drying operating state, the method further includes:

[0016] Pressurize the inside of the dryer until the pressure inside the dryer matches the pressure at the product gas outlet of the dryer during regeneration.

[0017] Optionally, the dryer is pressurized until the internal pressure of the dryer matches the pressure at the product gas outlet of the dryer during regeneration, further including:

[0018] Connect the product gas outlet of the dryer in drying mode and the product gas outlet of the dryer in regeneration mode to pressurize until the pressure inside the dryer is the same as the pressure at the product gas outlet of the dryer in regeneration mode.

[0019] Optionally, the operation process of the dryer in the drying state further includes:

[0020] Detect the pressure difference between the product gas inlet port and the product gas outlet port of the dryer when it is in drying operation;

[0021] When the differential pressure value is within the preset threshold range, the dryer in the drying state begins to work.

[0022] On the other hand, the present invention also provides an automatic control system for a dryer, including a data acquisition module, a processing module, and a control module, wherein,

[0023] The data acquisition module is used to acquire the sequential start-up status data, internal pressure value, constant temperature purging temperature data, heating data and cooling data of each dryer, and send them to the processing module;

[0024] The processing module is used to send control commands to the control module based on the acquired sequential start-up status data. The sequential start-up status data includes at least one dryer being in drying operation mode and at least one dryer being in regeneration operation mode or standby mode. The operation process of the dryer in regeneration operation mode includes:

[0025] The internal pressure of the dryer is released to the first preset pressure value, and regeneration gas is introduced into the dryer to the preset charging pressure value.

[0026] The inside of the dryer is purged at a low temperature for a preset low temperature purging time. After the low temperature purging is completed, the temperature is gradually increased until the purging temperature reaches the preset constant temperature purging temperature. The inside of the dryer is then purged at a constant temperature according to the preset constant temperature purging time and preset constant temperature purging temperature.

[0027] The internal temperature of the dryer is raised to a preset temperature and maintained at that temperature for a set time. After maintaining the temperature for the set time, the internal temperature of the dryer is lowered to the preset temperature.

[0028] The internal pressure of the dryer is depressurized again to the second preset pressure value, and the regenerated dryer is set to the drying working state. The dryer in the drying working state is then switched to the regeneration working state.

[0029] The control module controls the dryer according to the control commands issued by the processing module.

[0030] Optionally, the processing module includes at least three processors. The three processors determine the state of the dryer based on the data acquired by the data acquisition module, and output the determination result using a two-out-of-three voting method.

[0031] Optionally, it may also include a programming module, which is used to write the logic of the control instructions of the processing module.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides an automatic control method and system for a dryer, which eliminates the need for operator monitoring and operation at each stage, enabling the entire dryer regeneration process to achieve full automation. This greatly reduces the labor costs invested by the factory, improves the operating efficiency of the entire device, and, under ideal conditions, utilizes almost 100% of the operation time at each stage with no ineffective operations, making production more intelligent.

[0034] This invention performs low-temperature purging before high-temperature purging and before high-temperature heating, which allows hydrocarbon impurities in the bed to be removed from the dryer first, preventing coking from occurring in the equipment due to direct high-temperature heating, thus affecting the service life of the dryer. Attached Figure Description

[0035] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0036] Figure 1 This is a flowchart of the automatic control method for a dryer provided in Embodiment 1 of the present invention;

[0037] Figure 2 This is a flowchart of parallel operation provided in Embodiment 1 of the present invention;

[0038] Figure 3 This is a schematic diagram of the dryer provided in Embodiment 1 of the present invention;

[0039] Figure 4 This is a system block diagram of the automatic control system of the dryer provided in Embodiment 2 of the present invention;

[0040] Figure 5 This is a schematic diagram of the triple control of the processing module provided in Embodiment 2 of the present invention.

[0041] In the diagram: 1. Data acquisition module; 2. Processing module; 3. Control module; 4. Dryer. Detailed Implementation

[0042] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0043] Example 1

[0044] like Figure 1 As shown, the automatic control method for a dryer in this invention includes at least two dryers, and the automatic control method includes the following steps:

[0045] S1, acquire the sequential start-up status data of each dryer, and control the dryer according to the sequential start-up status data, wherein the sequential start-up status data includes at least one dryer in drying operation state and at least one dryer in regeneration operation state or standby state.

[0046] For example, let's first introduce the dryer. A dryer generally includes an outer shell and two dryer beds assembled inside the outer shell. The two dryer beds are the main bed and the protective bed. The protective bed is located above the main bed and is used to prevent the filtered water from flowing out of the dryer. Above the two dryers is the filter gas chamber, and below the two dryers is the product gas chamber. The two dryers are dryer A and dryer B. The sequential start-up status data is A regeneration / B feeding, which means that dryer A is in the regeneration working state and dryer B is in the drying working state.

[0047] Before a dryer is put into operation, it is necessary to ensure that the working air pressure conditions are met. Drying can only proceed effectively when a set pressure difference is achieved. Therefore, the pressure difference needs to be checked first. The process includes:

[0048] The pressure difference between the product gas inlet port and the product gas outlet port of the dryer in the drying operation state is detected by PDI803.

[0049] When the differential pressure value is within the preset threshold range, the dryer in the drying state begins to work.

[0050] When the differential pressure value is not within the preset differential pressure value threshold range, an alarm will be triggered, and if dryer A is in standby mode, the system will switch to dryer A.

[0051] The working process of a dryer in regeneration mode includes:

[0052] S2, the internal pressure of the dryer is released to the first preset pressure value, and regeneration gas is introduced into the dryer to the preset charging pressure value.

[0053] Please see Figure 3 The filtered gas chamber of dryer A is depressurized through a pressure relief pipe. The first pipe is equipped with a pressure relief valve X813 and a pressure relief flow control valve F802. The pressure relief flow control valve F802 is controlled by FIC801. When valve X813 is opened, the ramp of the PIC (Programmable Interrupt Controller) is reduced to 0.1MPa. After the gas is depressurized for 30 minutes, the internal pressure of dryer A is 0.14MPa. After the pressure reaches 0.14MPa, the next action is activated, namely, the pressurization action is activated. If it is not activated, an alarm is triggered to prompt manual handling. After activation, the pressure relief valve X813 is closed, the regeneration gas pressurization valve X811 is opened, and the cold regeneration gas flow control valve F801 is opened (opening degree is 10%). After the dryer A is pressurized with cold regeneration gas for 20 minutes, the pressure of dryer A reaches 0.6MPa. At this pressure value, the next action will be activated. If it is not activated, an alarm is triggered to prompt manual handling.

[0054] S3, perform low-temperature purging on the inside of the dryer according to the preset low-temperature purging time. After the low-temperature purging is completed, gradually increase the temperature for purging until the purging temperature reaches the preset constant temperature purging temperature. Perform constant temperature purging on the inside of the dryer according to the preset constant temperature purging time and preset constant temperature purging temperature.

[0055] Open the regeneration gas inlet valve X807. If the regeneration gas inlet valve X807 fails to operate, regeneration gas can be introduced for purging by opening the bypass valve of the regeneration gas inlet valve X811. Close the regeneration gas pressurization valve X811 and open the regeneration gas outlet valve X809. It can be seen that after 30 minutes, the cold regeneration gas flow control FIC (flow regulator) will be adjusted to 18.6 t / h. Figure 3 The intercooled regenerated gas flow control FIC is FIC801. If the flow rate adjusted by the intercooled regenerated gas flow control FIC does not meet the requirements, an alarm will be triggered to prompt manual handling. After the low-temperature purging is completed, the intercooled regenerated gas flow control FIC will be put into automatic mode, i.e., automatic adjustment mode, and the set value will be 18.6t / h. The intercooled regenerated gas flow control FIC will be put into cascade mode, and the regenerated temperature controller (TIC) will be put into automatic mode. After 2 hours, the set value will be gradually increased to 120℃ (if the TIC does not meet the requirements, an alarm will be triggered to prompt manual handling). The heating rate shall not exceed 50℃ / h. After 150 minutes, the TIC set value will be gradually increased to 230℃, and the heating rate shall not exceed 50℃ / h. The constant temperature purging will last for 1 hour.

[0056] S4, heat the inside of the dryer to the preset heating temperature and maintain it at that temperature for a set time. After maintaining the temperature for the set time, cool the inside of the dryer to the preset temperature.

[0057] Please see Figure 3 After 1 hour of constant temperature purging, the TIC setpoint is gradually increased to 230℃ after 150 minutes. The heating rate must not exceed 50℃ / h. If it does not reach 230℃, an alarm will be triggered to prompt manual handling. The bottom outlet temperature of the bed is checked to see if it has reached the set temperature. If it has not reached the set temperature, an alarm will be triggered and the TIC will be switched to manual control mode for adjustment.

[0058] After 150 minutes, the TIC setting value is gradually increased to 230℃. The heating rate must not exceed 50℃ / h. If the TIC set temperature is not reached or the set heating rate is exceeded, an alarm will be triggered. The temperature is kept constant for 8 hours. The temperature at the bottom of the bed outlet is checked to see if it reaches 230℃. If it does not reach 230℃, an alarm will be triggered and the system will switch to manual control.

[0059] After maintaining a constant temperature for 8 hours, the TIC setpoint will be gradually reduced to 30℃ after 4 hours. The cooling rate must not exceed 50℃ / h. If the TIC is not met, an alarm will be triggered.

[0060] After reaching 30℃, maintain the temperature for 4 hours and check the temperature at the bottom outlet of the bed. If the temperature at the bottom outlet of the bed does not reach 30℃, an alarm will be triggered and the system will switch to manual mode.

[0061] After completion, close valve F801 and close ramp F802.

[0062] S5, depressurize the inside of the dryer again to the second preset pressure value, please refer to Figure 3 Its pressure relief operation mode is: close the regenerated gas inlet valve X807 and the regenerated gas outlet valve X809;

[0063] Open pressure relief valves X813 and FA-2002, reduce pressure to 0.1 MPa using the PIC ramp, and after 20 minutes of gas depressurization, the pressure inside dryer A will reach 0.14 MPa, activating the next step. If the next step is not activated, an alarm will sound.

[0064] After the pressure relief is completed, since the switching process between the two states of the dryer requires parallel operation for a period of time before they both switch states, it is necessary to pressurize the regenerated dryer to prevent product gas backflow from occurring in the regenerated dryer during parallel operation due to the high internal pressure of the dryer that was previously in the drying state. The specific process includes:

[0065] Pressurize the inside of the dryer until the pressure inside the dryer matches the pressure at the product gas outlet of the dryer during regeneration.

[0066] It is known that, in order to reduce equipment and costs, the pressurization process can be achieved in the following way, the specific implementation process of which is as follows:

[0067] Connect the product gas outlet of the dryer in drying mode to the product gas outlet of the dryer in regeneration mode to pressurize until the internal pressure of the dryer matches the pressure at the product gas outlet of the dryer in regeneration mode. Please refer to [link to relevant documentation]. Figure 3 Close X813, open the product gas outlet bypass valve H801, open the ramp H803, control the pressurization rate to 34 kPa / min, pressurize dryer A, and after 30 minutes the pressure of dryer A reaches the activation pressure of 1.05 MPa, the next step can be activated.

[0068] Set the regenerated dryer to the drying working state, and then switch the dryer from the drying working state to the regeneration working state.

[0069] To avoid an unstable transition by stopping the drying process of the product gas during the switching process, the dryer is set to a drying state after regeneration, and then switched from the drying state to the regeneration state. This further includes:

[0070] The regenerated dryer and the dryer in drying operation are connected in parallel, and the regenerated dryer is in low flow rate operation.

[0071] After the dryer has been in parallel operation for a preset working time in the drying state, the regenerated dryer is set to the drying state, the dryer in the drying state stops working, and the operation is switched to the regeneration state.

[0072] Please see Figure 3 The above-mentioned parallel operation mode is as follows: Dryer A product gas inlet valve X801, dryer A runs in parallel with dryer B at a low flow rate for 15 minutes. The so-called low flow rate means that dryer A opens the product gas outlet bypass valve H801, and the gas output of this valve is less than that of the product gas outlet valve X803, so it is a low flow rate operation.

[0073] When the adsorption time of dryer B is up, open the X803 product gas outlet valve of dryer A and close the product gas outlet bypass valve H801. After the two dryers run in parallel for 30 minutes, open the X815 sampling valve of the moisture meter of dryer A.

[0074] Please see Figure 3 In addition to the valves mentioned above, the dryer A also includes: X801 product gas inlet valve, X803 product gas outlet valve, and H801 product gas outlet valve bypass valve; X815 is the analysis sampling valve for dryer A, which can be used to sample and analyze the interior of dryer A; A1081 is a humidity analyzer; PDI803 is the pressure difference detection device between the filter gas chamber and the product gas chamber of dryer A; P1081 is a pressure detection device; and T1803 is a temperature detection device. Correspondingly, dryer B includes: X802 product gas inlet valve, X810 regenerated gas outlet valve, pressure relief valve X814 (product gas outlet valve), H801 product gas outlet valve bypass valve, regenerated gas inlet valve X808, regenerated gas pressurization valve X812, X816 analysis sampling valve, A1082 humidity analyzer, PDI803 pressure difference detection device between the filter gas chamber and the product gas chamber of dryer B, P1082 pressure detection device, and T1804 temperature detection device.

[0075] Example 2

[0076] Please see Figure 4This embodiment provides an automatic control system for a dryer, including a data acquisition module, a processing module, and a control module, wherein...

[0077] Data acquisition module 1 is used to acquire the start-up status data, internal pressure value, constant temperature purging temperature data, heating data and cooling data of each dryer 4, and send them to processing module 2;

[0078] Processing module 2 is used to send control commands to control module 3 based on the acquired sequential start-up status data. The sequential start-up status data includes at least one dryer 4 being in drying operation mode and at least one dryer 4 being in regeneration operation mode or standby mode. The operation process of the dryer in regeneration operation mode includes:

[0079] The internal pressure of dryer 4 is released to the first preset pressure value, and regeneration gas is introduced into dryer 4 to the preset charging pressure value.

[0080] The inside of the dryer 4 is purged at low temperature for a preset low temperature purging time. After the low temperature purging is completed, the temperature is gradually increased until the purging temperature reaches the preset constant temperature purging temperature. The inside of the dryer 4 is then purged at a constant temperature according to the preset constant temperature purging time and preset constant temperature purging temperature.

[0081] Heat the inside of dryer 4 to a preset heating temperature and maintain it at that temperature for a set time. After maintaining the temperature for the set time, cool the inside of dryer 4 down to the preset temperature.

[0082] The internal pressure of dryer 4 is depressurized again to the second preset pressure value, and the state of regenerated dryer 4 is set to drying working state, and the state of dryer 4 in drying working state is changed to regeneration working state.

[0083] The control module 3 controls the dryer 4 according to the control commands issued by the processing module 2.

[0084] like Figure 5 As shown, for example, in order to ensure the safety and reliability of the judgment of the processing module, the processing module includes at least three processors. The three processors judge the state of the dryer based on the data acquired by the data acquisition module, and output the judgment result by a two-out-of-three voting method. In order to facilitate data storage, the processing module may also include a memory for storing some control data or other data.

[0085] To facilitate the modification or adjustment of the control logic parameters, a programming module is also provided. This programming module is used to write the logic of the control instructions of the processing module. The writing is generally done using the StrustText (structured text) programming language, which has high readability.

[0086] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. An automatic control method of a dryer characterized by, The drying machine comprises at least two dryers, and the automatic control method comprises the following steps: acquiring sequence control starting state data of each dryer, and controlling the dryers according to the sequence control starting state data, wherein the sequence control starting state data comprises at least one dryer in a drying working state and at least one dryer in a regeneration working state or a standby state, and the working process of the dryer in the regeneration working state comprises: pressure relief is performed in the dryer to a first preset pressure value, and regeneration gas is filled into the dryer to a preset filling pressure value; low-temperature purging is performed in the dryer according to a preset low-temperature purging time, after the low-temperature purging is completed, temperature purging is gradually performed until the purging temperature reaches a preset constant-temperature purging temperature, and constant-temperature purging is performed in the dryer according to the preset constant-temperature purging time and the preset constant-temperature purging temperature; the temperature in the dryer is raised to a preset temperature raising temperature and maintained for a set time, and then the temperature in the dryer is lowered to a preset temperature; the dryer in the regeneration working state is converted to the drying working state, and the dryer in the drying working state is converted to the regeneration working state; the regenerated dryer and the dryer in the drying working state are connected in parallel, and the regenerated dryer is in a small-flow working state; after parallel operation for a preset working time of the dryer in the drying working state, the regenerated dryer is converted to the drying working state, the dryer in the drying working state stops working, and is converted to the regeneration working state; after the pressure relief is performed in the dryer to the second preset pressure value, and before the regenerated dryer is converted to the drying working state, the dryer is also filled with pressure until the pressure in the dryer and the pressure value of a product gas outlet end of the dryer in the regeneration working state are consistent.

2. The automatic control method of a dryer according to claim 1, characterized in that, the filling of pressure in the dryer until the pressure in the dryer and the pressure value of the product gas outlet end of the dryer in the regeneration working state are consistent further comprises: the product gas outlet end of the dryer in the drying working state and the product gas outlet end of the dryer in the regeneration working state are connected to be filled with pressure until the pressure in the dryer and the pressure value of the product gas outlet end of the dryer in the regeneration working state are consistent.

3. The automatic control method of a dryer according to claim 1, characterized in that, the working process of the dryer in the drying working state further comprises: detecting a pressure difference value of a product gas input port and a product gas output port of the dryer in the drying working state; when the pressure difference value is within a preset threshold range of the pressure difference value, the dryer in the drying working state starts working.

4. An automatic control system for a dryer, characterized in that, The automatic control method of the drying machine according to any one of claims 1-3 comprises a data acquisition module, a processing module and a control module, wherein the data acquisition module is used to acquire sequence control starting state data, internal pressure values, constant-temperature purging temperature data, temperature raising data and temperature lowering data of each dryer, and sends the data to the processing module; The processing module is configured to send a control instruction to the control module according to the obtained sequence control starting state data, wherein the sequence control starting state data includes at least one dryer in a drying working state and at least one dryer in a regeneration working state or a standby state, and the working process of the dryer in the regeneration working state includes: Pressure relief is performed on the inside of the dryer to a first preset pressure value, and the inside of the dryer is filled with regeneration gas to a preset pressure charging pressure value; Low-temperature blowing is performed on the inside of the dryer according to a preset low-temperature blowing time, after the low-temperature blowing is completed, temperature rising blowing is gradually performed until the blowing temperature reaches a preset constant-temperature blowing temperature, and constant-temperature blowing is performed on the inside of the dryer according to the preset constant-temperature blowing time and the preset constant-temperature blowing temperature; The inside of the dryer is heated to a preset temperature rising temperature and kept at the temperature for a set time, after the set time is kept, the inside of the dryer is cooled to a preset temperature; The inside of the dryer is pressure relieved again to a second preset pressure value, the state of the regenerated dryer is set to the drying working state, and the state of the dryer in the drying working state is converted to the regeneration working state; The control module controls the dryer according to the control instruction sent by the processing module.

5. An automatic control system for a drying machine according to claim 4, characterized in that, The processing module includes at least three processors, the three processors judge the state of the dryer according to the data obtained by the data acquisition module, and a three-out-of-two voting mode is adopted to output a judgment result.

6. An automatic control system for a drying machine according to claim 4, characterized in that, Further comprising a programming module, the programming module is configured to program the logic of the control instruction of the processing module.

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