CN114797144B - Rectifying column top temperature control system and rectifying column control system - Google Patents
Rectifying column top temperature control system and rectifying column control system Download PDFInfo
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- CN114797144B CN114797144B CN202210345335.1A CN202210345335A CN114797144B CN 114797144 B CN114797144 B CN 114797144B CN 202210345335 A CN202210345335 A CN 202210345335A CN 114797144 B CN114797144 B CN 114797144B
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- 238000010992 reflux Methods 0.000 claims abstract description 61
- 238000001514 detection method Methods 0.000 claims abstract description 24
- 230000001105 regulatory effect Effects 0.000 claims description 23
- 230000001276 controlling effect Effects 0.000 claims description 6
- 230000007613 environmental effect Effects 0.000 description 9
- 239000004215 Carbon black (E152) Substances 0.000 description 5
- 229930195733 hydrocarbon Natural products 0.000 description 5
- 150000002430 hydrocarbons Chemical class 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/42—Regulation; Control
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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Abstract
The invention provides a rectifying tower top temperature control system and a rectifying tower control system, wherein the temperature control system comprises: the system comprises a tower top temperature main controller, a tower bottom temperature auxiliary controller and a tower top temperature detection device, wherein the tower top temperature main controller is used for forwarding the tower top temperature to the tower bottom temperature auxiliary controller, and one or more of the following operations are performed according to the tower top temperature so as to control the tower top temperature within a set tower top temperature range: and outputting an adjusting signal to the air cooler, outputting an overhead temperature adjusting instruction to a tower bottom temperature auxiliary controller, adjusting a steam valve through the tower bottom temperature auxiliary controller, and outputting an adjusting signal to a reflux valve. The tower bottom temperature auxiliary controller is used for outputting an adjusting signal to the steam valve according to the tower top temperature adjusting instruction and the tower top temperature. The rectifying tower top temperature control system provided by the invention can reduce the influence of interference on the tower top temperature main controller, reduce hysteresis and improve the accurate control of the tower temperature.
Description
Technical Field
The invention relates to the technical field of rectifying tower control, in particular to a rectifying tower top temperature control system and a rectifying tower control system.
Background
The rectifying tower is one of very important equipment in the industries of coal chemical industry, petrochemical industry, chemical fertilizers and the like, particularly in the production of propylene (MTP for short) from methanol in the coal chemical industry, the technological process is long, the rectifying tower is core equipment of a rectifying device, and the control of the rectifying tower is stable or not, so that the quality and the yield of products are affected, and the control of a downstream rectifying tower is directly affected.
Factors influencing the stable control of the rectifying tower are the variation of relevant parameters such as feed components, pressure, temperature, feed quantity and reflux quantity. Because the feed components change in real time, no accurate detection equipment is used for component measurement and analysis at present, and the temperature of the rectifying tower is generally used as a controlled variable to form a conventional PID control loop with a steam valve under the condition of stable tower pressure control so as to regulate the temperature of the rectifying tower. And the conventional PID control system adjusts the phenomenon that the dynamic response is delayed greatly, so that the rectification production requirement can not be met.
Disclosure of Invention
Aiming at the technical problems of slow dynamic response and inaccurate temperature regulation of a temperature control system in the prior art, the invention provides a rectifying tower top temperature control system and a rectifying tower control system, and the temperature control system can reduce the influence of interference on a main variable, improve the control quality of the temperature of the rectifying tower and ensure the accurate control of the temperature.
To achieve the above object, a first aspect of the present invention provides a rectifying tower top temperature control system, comprising: the system comprises a tower top temperature main controller, a tower bottom temperature auxiliary controller and a tower top temperature detection device;
the tower top temperature detection device is used for detecting the temperature of the tower top in real time;
the overhead temperature master controller is used for forwarding the overhead temperature to the tower bottom temperature sub-controller, and performing one or more of the following operations according to the overhead temperature so as to control the overhead temperature within a set overhead temperature range: outputting an adjusting signal to the air cooler; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller, and regulating a steam valve through the tower bottom temperature auxiliary controller; outputting a regulating signal to a reflux valve;
and the tower bottom temperature auxiliary controller is used for outputting an adjusting signal to the steam valve according to the tower top temperature adjusting instruction and the tower top temperature.
Further, the control system further includes: the tower bottom temperature detection device is used for detecting the temperature of the tower bottom in real time; the bottom temperature auxiliary controller is also used for outputting an adjusting signal to the steam valve according to the bottom temperature and the top temperature so as to control the bottom temperature within a set bottom temperature range.
Further, the tower top temperature main controller is used for: outputting an adjusting signal for increasing the power of the air cooler to the air cooler under the condition that the difference between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller when the power of the air cooler reaches the operation maximum value and the difference value between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, and reducing the opening of a steam valve through the tower bottom temperature auxiliary controller; and when the power of the air cooler reaches the maximum operation value, the opening of the steam valve reaches the adjustable minimum opening, and the difference value between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, outputting an adjusting signal for increasing the opening of the reflux valve to the reflux valve.
Further, at least one constant-speed fan and at least one variable-speed fan are arranged in the air cooler; and outputting an adjusting signal for increasing the power of the air cooler to the air cooler when the difference between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference, comprising: at T d -T s ＝n*T p In the case of (1), starting n constant speed fans in the at least one constant speed fan, wherein T is d Is the temperature of the top of the tower, T s In order to set the temperature of the tower top, n is a constant and is less than or equal to the number of constant-speed fans, T p The temperature is the corresponding dropping temperature when only one constant speed fan is started; at T d -T s ＝n*T p And under the condition of +b, starting n constant speed fans in the at least one constant speed fan and starting a variable speed fan, wherein b is a constant.
Further, the tower top temperature main controller is used for: outputting an adjusting signal for reducing the power of the air cooler to the air cooler under the condition that the difference between the set tower top temperature and the tower top temperature is larger than the set tower top temperature difference; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller when the power of the air cooler reaches the operation minimum value and the difference value between the set tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, and increasing the opening of the steam valve through the tower bottom temperature auxiliary controller; and outputting an adjusting signal for reducing the opening degree of the reflux valve to the reflux valve under the conditions that the power of the air cooler reaches the operation minimum value, the opening degree of the steam valve reaches the adjustable maximum opening degree and the difference value between the set tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value.
Further, at least one constant-speed fan and at least one variable-speed fan are arranged in the air cooler; and outputting an adjusting signal for reducing the power of the air cooler to the air cooler when the difference between the set tower top temperature and the tower top temperature is larger than the set tower top temperature difference, comprising: at T s -T d ＝n*T p In the case of (1), turning off n constant speed fans of the at least one constant speed fan, wherein T d Is the temperature of the top of the tower, T s In order to set the temperature of the tower top, n is a constant and is less than or equal to the number of constant-speed fans, T p The temperature is the corresponding dropping temperature when only one constant speed fan is started; at T s -T d ＝n*T p And under the condition of +b, turning off n constant speed fans in the at least one constant speed fan and turning off one variable speed fan, wherein b is a constant.
Further, the system further comprises: a feedforward controller, and an ambient temperature detection device for detecting an ambient temperature; the feedforward controller is used for feeding back the ambient temperature to the tower top temperature main controller; the tower top temperature main controller is also used for outputting an adjusting signal to the air cooler according to the ambient temperature so as to control the tower top temperature within a set tower top temperature range.
Further, the outputting of the adjusting signal to the air cooler according to the ambient temperature and the tower top temperature to control the tower top temperature within a set tower top temperature range includes: outputting an adjusting signal for reducing the power of the air cooler to the air cooler under the condition that the ambient temperature is greater than a first set temperature; and outputting an adjusting signal for increasing the power of the air cooler to the air cooler when the environmental temperature is smaller than a second set temperature, wherein the first set temperature is larger than the second set temperature.
Further, the system further comprises: and the orifice plate flowmeter is arranged between the rectifying tower and the reflux valve and is used for detecting the reflux quantity passing through the reflux valve.
In a second aspect the invention provides a rectifying column control system comprising a rectifying column top temperature control system as described above.
Through the technical scheme provided by the invention, the invention has at least the following technical effects:
the rectifying tower top temperature control system comprises a tower top temperature main controller, a tower bottom temperature auxiliary controller and a tower top temperature detection device, wherein the tower top temperature detection device is used for detecting the tower top temperature in real time, the tower top temperature main controller is used for forwarding the tower top temperature to the tower bottom temperature auxiliary controller, and one or more of the following operations are performed according to the tower top temperature so as to control the tower top temperature within a set tower top temperature range: and outputting an adjusting signal to the air cooler, outputting an overhead temperature adjusting instruction to a tower bottom temperature auxiliary controller, adjusting a steam valve through the tower bottom temperature auxiliary controller, and outputting an adjusting signal to a reflux valve. The tower bottom temperature auxiliary controller is used for outputting an adjusting signal to the steam valve according to the tower top temperature adjusting instruction and the tower top temperature. According to the rectifying tower top temperature control system provided by the invention, the control quality of the tower top temperature main controller can be improved by arranging the tower bottom temperature auxiliary controller, the effect of advanced control on the interference entering the auxiliary loop is achieved, the influence of the interference on the tower top temperature main controller is reduced, the hysteresis is reduced, and the accurate control on the tower temperature is improved.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain, without limitation, the embodiments of the invention. In the drawings:
FIG. 1 is a flow chart of a rectifying tower top temperature control system provided by an embodiment of the invention;
fig. 2 is a schematic structural diagram of a rectifying tower in the rectifying tower top temperature control system according to the embodiment of the present invention;
fig. 3 is a schematic diagram of a tower top temperature test in a rectifying tower top temperature control system according to an embodiment of the present invention.
Detailed Description
The following describes the detailed implementation of the embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
In the present invention, unless otherwise indicated, terms of orientation such as "upper, lower, top, bottom" are used generally with respect to the orientation shown in the drawings or with respect to the positional relationship of the various components with respect to one another in the vertical, vertical or gravitational directions.
The invention will be described in detail below with reference to the drawings in connection with embodiments.
Referring to fig. 1-3, an embodiment of the present invention provides a temperature control system at the top of a rectifying tower, wherein a reboiler is arranged at the bottom of the rectifying tower, a gas phase outlet of the rectifying tower is sequentially connected with an air cooler and a reflux tank, and the air cooler is connected between the rectifying tower and the reflux tank through a pipeline; the reflux tank is provided with a reflux valve for controlling the reflux quantity of the light component which is refluxed to the rectifying tower; the reboiler is provided with a steam valve for controlling the steam quantity entering the reboiler; the control system includes:
the system comprises a tower top temperature main controller, a tower bottom temperature auxiliary controller and a tower top temperature detection device;
the tower top temperature detection device is used for detecting the temperature of the tower top in real time;
the overhead temperature master controller is used for forwarding the overhead temperature to the tower bottom temperature sub-controller, and performing one or more of the following operations according to the overhead temperature so as to control the overhead temperature within a set overhead temperature range: outputting an adjusting signal to the air cooler; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller, and regulating a steam valve through the tower bottom temperature auxiliary controller; outputting a regulating signal to a reflux valve;
and the tower bottom temperature auxiliary controller is used for outputting an adjusting signal to the steam valve according to the tower top temperature adjusting instruction and the tower top temperature.
Specifically, in the embodiment of the invention, the rectifying tower shown in fig. 2 is composed of 40 layers of tower plates from top to bottom, the bottom of the rectifying tower is provided with a reboiler, an inlet of the reboiler is connected with a steam valve, the top of the rectifying tower is sequentially provided with an air cooler and a reflux tank, one path of output end of the reflux tank is connected to the rectifying tower through the reflux valve, and the other path of output end of the reflux tank outputs light components. Gaseous hydrocarbon from the front working section enters a rectifying tower, the temperature of the gaseous hydrocarbon in the rectifying tower is regulated by controlling the steam quantity entering a reboiler through a tower bottom steam valve TV4101 to carry out gas-liquid separation, and liquid hydrocarbon is sent out from the tower bottom after rectification. Gaseous light components are cooled from the top of the tower through an air cooler and enter a reflux tank, a part of the light components at the outlet of the reflux tank are controlled by a reflux valve FV4101 to return to the rectifying tower for adjusting the temperature of the top of the tower, and a part of the light components are sent out to the rectifying tower at a rear working section. The temperature of the tower top is a main parameter for monitoring light components of the tower top, a tower top temperature detection device TT-4112 is arranged at the tower top, the temperature detection device of the tower top detects the temperature of the tower top in real time, the temperature control system further comprises a tower top temperature main controller and a tower bottom temperature auxiliary controller, the tower top temperature detection device is connected with the input end of the tower top temperature main controller, the detected temperature of the tower top is transmitted to the tower top temperature main controller in real time, the output end of the tower top temperature main controller is connected with a reflux valve, an air cooler and the tower bottom temperature auxiliary controller, and after the tower top temperature main controller receives the temperature of the tower top, the temperature of the tower top is forwarded to the tower bottom temperature auxiliary controller, and the following operations are executed according to the temperature of the tower top: outputting an adjusting signal to the air cooler; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller, and regulating a steam valve through the tower bottom temperature auxiliary controller; and outputting the adjusting signal to the reflux valve.
According to the invention, the main tower top temperature controller can set the control priority of the reflux valve, the air cooler and the auxiliary tower bottom temperature controller according to actual conditions, and one or more of the main tower top temperature controllers can be selected for control according to the control priority.
In one possible embodiment, in the case where the overhead temperature is not within the set overhead temperature range, the overhead temperature main controller outputs an adjustment signal to the air cooler, through which the overhead temperature is controlled. If the air cooler cannot control the temperature of the tower top within the set temperature range of the tower top according to the regulating instruction, the main tower temperature controller outputs a regulating instruction of the temperature of the tower top to the auxiliary tower bottom controller, and the steam valve is regulated by the auxiliary tower bottom controller. The tower bottom temperature auxiliary controller outputs an adjusting signal to the steam valve according to the tower top temperature adjusting instruction and the tower top temperature, and the tower top temperature is controlled through the steam valve. If the temperature of the tower top cannot be controlled within the set temperature range, the main controller of the temperature of the tower top outputs an adjusting signal to the reflux valve, and the temperature of the tower top is controlled through the reflux valve.
According to the temperature control system provided by the invention, the control quality of the tower top temperature main controller can be improved by arranging the tower bottom temperature auxiliary controller, the interference entering the auxiliary loop is controlled in advance, the influence of the interference on the tower top temperature main controller is reduced, the hysteresis is reduced, and the accurate control on the tower temperature is improved.
Further, the control system further includes: the tower bottom temperature detection device is used for detecting the temperature of the tower bottom in real time; the bottom temperature auxiliary controller is also used for outputting an adjusting signal to the steam valve according to the bottom temperature and the top temperature so as to control the bottom temperature within a set bottom temperature range.
Specifically, in the embodiment of the invention, a tower bottom temperature detection device TT-4111 is arranged at the tower bottom of the rectifying tower, the tower bottom temperature is a key parameter for monitoring the tower bottom heavy component liquid hydrocarbon, the tower bottom temperature is regulated, and meanwhile, the tower bottom temperature is required to be considered, so that the tower bottom temperature is ensured to be within a set tower bottom temperature range. Therefore, the tower bottom temperature auxiliary controller is used for controlling the tower top temperature through the steam valve, and also needs to monitor the tower bottom temperature, and under the condition that the tower bottom temperature is not in the set range of the tower bottom, the tower bottom temperature auxiliary controller outputs a regulating signal to the steam valve, and the tower bottom temperature is controlled in the set range of the tower bottom temperature through the steam valve.
In one possible implementation manner, when the temperature of the tower top exceeds the set temperature range, the tower bottom temperature auxiliary controller receives a tower top temperature adjusting instruction and outputs an adjusting signal to the steam valve to reduce the opening degree of the steam valve, and when the temperature of the tower top is adjusted, the tower bottom temperature auxiliary controller receives the temperature of the tower bottom in real time, and if the temperature of the tower bottom is reduced and is lower than the set range of the tower bottom, the opening degree of the steam valve is increased.
According to the temperature control system provided by the invention, the bottom temperature and the top temperature can be considered, the bottom temperature is controlled within the set bottom temperature range, and the yield efficiency and the yield purity of the bottom heavy component liquid hydrocarbon are ensured.
Further, the tower top temperature main controller is used for: outputting an adjusting signal for increasing the power of the air cooler to the air cooler under the condition that the difference between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller when the power of the air cooler reaches the operation maximum value and the difference value between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, and reducing the opening of a steam valve through the tower bottom temperature auxiliary controller; and when the power of the air cooler reaches the maximum operation value, the opening of the steam valve reaches the adjustable minimum opening, and the difference value between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, outputting an adjusting signal for increasing the opening of the reflux valve to the reflux valve.
Specifically, in the embodiment of the invention, when the temperature of the tower top is increased, the difference between the temperature of the tower top and the set temperature of the tower top is larger than the set temperature difference of the tower top, and the main controller of the temperature of the tower top outputs an adjusting signal for increasing the power of the air cooler to the air cooler. At least one constant speed fan and at least one variable speed fan are arranged in the air cooler, and at T d -T s ＝n*T p In the case of (1), starting n constant speed fans in the at least one constant speed fan, wherein T is d Is the temperature of the top of the tower, T s In order to set the temperature of the tower top, n is a constant and is less than or equal to the number of constant-speed fans, T p The temperature is the corresponding dropping temperature when only one constant speed fan is started; at T d -T s ＝n*T p And under the condition of +b, starting n constant speed fans in the at least one constant speed fan and starting a variable speed fan, wherein b is a constant.
In one possible implementation, 5 constant speeds are arranged in the air coolerThe fan and 1 variable speed fan can cool the temperature of the tower top by 5 ℃ under the condition that one constant speed air is started, and can cool the tower top by 0-5 ℃ under the condition that one variable speed fan is started, the variable speed fan can cooperate with the constant speed fan to accurately control the temperature of the tower top, and if T d -T s If = 2*5 ℃, two constant speed fans are turned on, if T d -T s = 5*5 ℃, then all 5 constant speed fans are turned on. If T d -T s When the temperature is 2 x 5+3 ℃, two constant-speed fans and one variable-speed fan are started, the temperature at the top of the tower is precisely reduced through the variable-speed fan, if T d -T s If the temperature is 3 ℃, a variable speed fan is started, if T d -T s =5×5+4 ℃, all constant speed fans and variable speed fans are turned on.
Under the condition that all constant-speed fans and variable-speed fans are started, the temperature of the tower top cannot be controlled within a set temperature range of the tower top, and then the main tower top temperature controller outputs a tower top temperature adjusting instruction to the auxiliary tower bottom temperature controller, and the opening of the steam valve is reduced through the auxiliary tower bottom temperature controller. Under the condition that the opening of the steam valve reaches the adjustable minimum opening and all constant-speed fans and variable-speed fans are started, whether the difference value between the set top temperature and the set top temperature is larger than the set top temperature difference value is set, the top temperature main controller outputs an adjusting signal for increasing the opening of the reflux valve to the reflux valve, and the reflux amount of light components which reflux to the rectifying tower is increased to reduce the top temperature.
Further, the tower top temperature main controller is used for: outputting an adjusting signal for reducing the power of the air cooler to the air cooler under the condition that the difference between the set tower top temperature and the tower top temperature is larger than the set tower top temperature difference; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller when the power of the air cooler reaches the operation minimum value and the difference value between the set tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, and increasing the opening of the steam valve through the tower bottom temperature auxiliary controller; and outputting an adjusting signal for reducing the opening degree of the reflux valve to the reflux valve under the conditions that the power of the air cooler reaches the operation minimum value, the opening degree of the steam valve reaches the adjustable maximum opening degree and the difference value between the set tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value.
Specifically, in the embodiment of the invention, when the temperature of the tower top is reduced, the difference between the set temperature of the tower top and the temperature of the tower top is larger than the set temperature difference of the tower top, and the main controller of the temperature of the tower top outputs an adjusting signal for reducing the power of the air cooler to the air cooler. At least one constant speed fan and at least one variable speed fan are arranged in the air cooler, and at T s -T d ＝n*T p In the case of (1), turning off n constant speed fans of the at least one constant speed fan, wherein T d Is the temperature of the top of the tower, T s In order to set the temperature of the tower top, n is a constant and is less than or equal to the number of constant-speed fans, T p The temperature is the corresponding dropping temperature when only one constant speed fan is started; at T s -T d ＝n*T p And under the condition of +b, turning off n constant speed fans in the at least one constant speed fan and turning off one variable speed fan, wherein b is a constant.
In one possible implementation mode, 5 constant-speed fans and 1 variable-speed fan are arranged in the air cooler, the temperature of the tower top can be reduced by 5 ℃ under the condition that one constant-speed fan is started, the temperature of the tower top can be reduced by 0-5 ℃ under the condition that one variable-speed fan is started, the variable-speed fan can cooperate with the constant-speed fan to accurately control the temperature of the tower top, if T s -T d If = 2*5 ℃, two constant speed fans are turned off, if T s -T d = 5*5 ℃, all 5 constant speed fans are turned off. If T s -T d When the temperature is 2×5+3 ℃, two constant-speed fans and one variable-speed fan are turned off, the temperature at the top of the tower is precisely reduced by the variable-speed fan, if T s -T d =5×5+4 ℃, all constant speed fans and variable speed fans are turned off.
Under the condition that all constant-speed fans and variable-speed fans are closed, the temperature of the tower top cannot be controlled within a set temperature range of the tower top, and then the main tower top temperature controller outputs a tower top temperature adjusting instruction to the auxiliary tower bottom temperature controller, and the opening of the steam valve is increased through the auxiliary tower bottom temperature controller. Under the condition that the opening of the steam valve reaches the adjustable maximum opening and all the constant-speed fans and the variable-speed fans are closed, if the difference value between the set tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, the tower top temperature main controller outputs an adjusting signal for reducing the opening of the reflux valve to the reflux valve, and the reflux quantity of light components which reflux to the rectifying tower is reduced so as to improve the tower top temperature.
According to the temperature control system provided by the invention, the control quality of the tower top temperature main controller can be improved by arranging the tower bottom temperature auxiliary controller, the effect of advanced control on the interference entering the auxiliary loop is achieved, the influence of the interference on the tower top temperature main controller is reduced, the hysteresis is reduced, and the tower top temperature is effectively reduced.
In this embodiment, the set top temperature of the top of the tower is 67 ℃ and the set top temperature difference is 5 ℃, please refer to fig. 3, and the temperature control system of the rectifying tower top according to the present invention can control the top temperature within 67±5 ℃.
Further, the system further comprises: a feedforward controller, and an ambient temperature detection device for detecting an ambient temperature; the feedforward controller is used for feeding back the ambient temperature to the tower top temperature main controller; the tower top temperature main controller is also used for outputting an adjusting signal to the air cooler according to the ambient temperature so as to control the tower top temperature within a set tower top temperature range.
Specifically, in the embodiment of the invention, a feedforward controller and an environmental temperature detection device for detecting the environmental temperature are further arranged, the input end of the feedforward controller is connected with the environmental temperature detection device for detecting the environmental temperature, the output end of the feedforward controller is connected with a tower top temperature main controller, and the tower top temperature main controller can output an adjusting signal to the air cooler according to the environmental temperature so as to control the temperature of the tower top within a set temperature range of the tower top.
According to the temperature control system provided by the invention, the air cooler can be timely adjusted by feeding back the feedforward control to the tower top temperature main controller in advance, so that disturbance caused by environmental temperature change is eliminated, and interference of the environmental temperature on temperature control of the rectifying tower is avoided.
Further, the outputting of the adjusting signal to the air cooler according to the ambient temperature and the tower top temperature to control the tower top temperature within a set tower top temperature range includes: outputting an adjusting signal for reducing the power of the air cooler to the air cooler under the condition that the ambient temperature is greater than a first set temperature; and outputting an adjusting signal for increasing the power of the air cooler to the air cooler when the environmental temperature is smaller than a second set temperature, wherein the first set temperature is larger than the second set temperature.
Specifically, in the embodiment of the invention, if the ambient temperature is greater than the first set temperature, the tower top temperature main controller outputs an adjusting signal for reducing the power of the air cooler to the air cooler, if the difference between the ambient temperature and the first set temperature is less than a set difference (for example, 3 ℃), the variable frequency fan is turned off, and if the difference between the ambient temperature and the first set temperature is greater than the set difference, the variable frequency fan and at least one fixed frequency fan are turned off. If the ambient temperature is less than the second set temperature, the tower top temperature main controller outputs an adjusting signal for improving the power of the air cooler to the air cooler, if the difference between the ambient temperature and the second set temperature is less than a set difference (such as 4 ℃), the variable frequency fan is started, and if the difference between the ambient temperature and the second set temperature is greater than the set difference, the at least one fixed frequency fan and the variable frequency fan are started.
According to the temperature control system provided by the invention, the constant-speed fan and the variable-speed fan can be flexibly allocated, and the interference of the ambient temperature on the temperature control of the rectifying tower is avoided.
Further, the system further comprises: and the orifice plate flowmeter is arranged between the rectifying tower and the reflux valve and is used for detecting the reflux quantity passing through the reflux valve.
Specifically, in the embodiment of the invention, an orifice plate flowmeter is arranged between the rectifying tower and the reflux valve, and the tower top temperature main controller is connected with the orifice plate flowmeter, so that the size of the reflux quantity passing through the reflux valve can be determined in real time.
In a second aspect the invention provides a rectifying column control system comprising a rectifying column top temperature control system as described above.
The rectifying tower top temperature control system comprises a tower top temperature main controller, a tower bottom temperature auxiliary controller and a tower top temperature detection device, wherein the tower top temperature detection device is used for detecting the tower top temperature in real time, the tower top temperature main controller is used for forwarding the tower top temperature to the tower bottom temperature auxiliary controller, and one or more of the following operations are performed according to the tower top temperature so as to control the tower top temperature within a set tower top temperature range: and outputting an adjusting signal to the air cooler, outputting an overhead temperature adjusting instruction to a tower bottom temperature auxiliary controller, adjusting a steam valve through the tower bottom temperature auxiliary controller, and outputting an adjusting signal to a reflux valve. The tower bottom temperature auxiliary controller is used for outputting an adjusting signal to the steam valve according to the tower top temperature adjusting instruction and the tower top temperature. According to the rectifying tower top temperature control system provided by the invention, the control quality of the tower top temperature main controller can be improved by arranging the tower bottom temperature auxiliary controller, and the effect of advanced control on the interference entering the auxiliary loop is achieved, so that the influence of the interference on the tower top temperature main controller is reduced, hysteresis is reduced, and the accurate control on the tower temperature is improved.
The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.
In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further.
Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.
Claims (7)
1. The temperature control system of the top of the rectifying tower is characterized in that a reboiler is arranged at the bottom of the rectifying tower, a gas phase outlet of the rectifying tower is sequentially connected with an air cooler and a reflux tank, and the air cooler is connected between the rectifying tower and the reflux tank through a pipeline; the reflux tank is provided with a reflux valve for controlling the reflux quantity of the light component which is refluxed to the rectifying tower; the reboiler is provided with a steam valve for controlling the steam quantity entering the reboiler; characterized in that the control system comprises:
the system comprises a tower top temperature main controller, a tower bottom temperature auxiliary controller and a tower top temperature detection device;
the tower top temperature detection device is used for detecting the temperature of the tower top in real time;
the overhead temperature master controller is used for forwarding the overhead temperature to the tower bottom temperature sub-controller, and performing one or more of the following operations according to the overhead temperature so as to control the overhead temperature within a set overhead temperature range:
outputting an adjusting signal to the air cooler;
outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller, and regulating a steam valve through the tower bottom temperature auxiliary controller;
outputting a regulating signal to a reflux valve;
outputting an adjusting signal for increasing the power of the air cooler to the air cooler under the condition that the difference between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller when the power of the air cooler reaches the operation maximum value and the difference value between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, and reducing the opening of a steam valve through the tower bottom temperature auxiliary controller; outputting an adjusting signal for increasing the opening of the reflux valve to the reflux valve under the conditions that the power of the air cooler reaches the maximum operation value, the opening of the steam valve reaches the minimum adjustable opening and the difference between the temperature of the tower top and the set temperature of the tower top is larger than the set temperature difference of the tower top;
outputting an adjusting signal for reducing the power of the air cooler to the air cooler under the condition that the difference between the set tower top temperature and the tower top temperature is larger than the set tower top temperature difference; outputting a tower top temperature regulating instruction to a tower bottom temperature auxiliary controller when the power of the air cooler reaches the operation minimum value and the difference value between the set tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value, and increasing the opening of the steam valve through the tower bottom temperature auxiliary controller; outputting an adjusting signal for reducing the opening degree of the reflux valve to the reflux valve under the conditions that the power of the air cooler reaches the operation minimum value, the opening degree of the steam valve reaches the adjustable maximum opening degree and the difference value between the set tower top temperature and the set tower top temperature is larger than the set tower top temperature difference value;
and the tower bottom temperature auxiliary controller is used for outputting an adjusting signal to the steam valve according to the tower top temperature adjusting instruction and the tower top temperature.
2. The control system of claim 1, wherein the control system further comprises: the tower bottom temperature detection device is used for detecting the temperature of the tower bottom in real time;
the bottom temperature auxiliary controller is also used for outputting an adjusting signal to the steam valve according to the bottom temperature and the top temperature so as to control the bottom temperature within a set bottom temperature range.
3. The control system of claim 1, wherein the control system is configured to control the control system,
at least one constant speed fan and at least one variable speed fan are arranged in the air cooler;
and outputting an adjusting signal for increasing the power of the air cooler to the air cooler when the difference between the tower top temperature and the set tower top temperature is larger than the set tower top temperature difference, comprising:
at T d -T s =n*T p In the case of (1), starting n constant speed fans in the at least one constant speed fan, wherein T is d Is the temperature of the top of the tower, T s In order to set the temperature of the tower top, n is a constant and is less than or equal to the number of constant-speed fans, T p The temperature is the corresponding dropping temperature when only one constant speed fan is started;
at T d -T s =n*T p And under the condition of +b, starting n constant speed fans in the at least one constant speed fan and starting a variable speed fan, wherein b is a constant.
4. The control system of claim 1, wherein the control system is configured to control the control system,
at least one constant speed fan and at least one variable speed fan are arranged in the air cooler;
and outputting an adjusting signal for reducing the power of the air cooler to the air cooler when the difference between the set tower top temperature and the tower top temperature is larger than the set tower top temperature difference, comprising:
at T s -T d =n*T p In the case of (1), turning off n constant speed fans of the at least one constant speed fan, wherein T d Is the temperature of the top of the tower, T s In order to set the temperature of the tower top, n is a constant and is less than or equal to the number of constant-speed fans, T p The temperature is the corresponding dropping temperature when only one constant speed fan is started;
at T s -T d =n*T p And under the condition of +b, turning off n constant speed fans in the at least one constant speed fan and turning off one variable speed fan, wherein b is a constant.
5. The control system of claim 1, wherein the system further comprises: a feedforward controller, and an ambient temperature detection device for detecting an ambient temperature;
the feedforward controller is used for feeding back the ambient temperature to the tower top temperature main controller;
the tower top temperature main controller is also used for outputting an adjusting signal to the air cooler according to the ambient temperature so as to control the tower top temperature within a set tower top temperature range.
6. The control system of claim 1, wherein the system further comprises: and the orifice plate flowmeter is arranged between the rectifying tower and the reflux valve and is used for detecting the reflux quantity passing through the reflux valve.
7. A rectifying column control system comprising the rectifying column top temperature control system of any one of claims 1 to 6.
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