CN110595153A - Control method for air feeding amount in automatic load changing process of air separation device - Google Patents
Control method for air feeding amount in automatic load changing process of air separation device Download PDFInfo
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- CN110595153A CN110595153A CN201810600952.5A CN201810600952A CN110595153A CN 110595153 A CN110595153 A CN 110595153A CN 201810600952 A CN201810600952 A CN 201810600952A CN 110595153 A CN110595153 A CN 110595153A
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- air
- flow
- value
- feeding
- target value
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04763—Start-up or control of the process; Details of the apparatus used
- F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
- F25J3/04812—Different modes, i.e. "runs" of operation
- F25J3/0483—Rapid load change of the air fractionation unit
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04763—Start-up or control of the process; Details of the apparatus used
- F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
- F25J3/04812—Different modes, i.e. "runs" of operation
- F25J3/04836—Variable air feed, i.e. "load" or product demand during specified periods, e.g. during periods with high respectively low power costs
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04763—Start-up or control of the process; Details of the apparatus used
- F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
- F25J3/04848—Control strategy, e.g. advanced process control or dynamic modeling
Abstract
The invention relates to a method for controlling air feeding quantity in an automatic load-changing process of an air separation device, which is characterized in that main variables influencing parameters of the air feeding quantity in the air separation device are extracted, wherein the main variables comprise oxygen flow, argon content of argon fraction, oxygen purity, flow of expanded air going to a tower, nitrogen flow, waste nitrogen flow, opening degree of a regulating valve of liquid nitrogen going to the tower and the like; establishing a relation model between the parameters and the air feeding quantity through a neural network; calculating a calculated value of the air flow rate through the target value of the oxygen flow rate and the current value of the extracted parameter; and multiplying the difference value between the calculated value and the current value of the air flow by a coefficient function to obtain an incremental value of the air flow, adding the current value of the air flow to the incremental value to obtain a target value of the air feeding flow, and feeding the target value to a controller to realize the control of the air feeding flow in the load varying process of the air separation unit. The invention can make the air separation device reach a stable state quickly in the process of changing load, and all parameters meet the quality requirement.
Description
Technical Field
The invention relates to the technical field of air separation, in particular to a method for controlling air feeding amount in an automatic load changing process of an air separation device.
Background
With the development of the industrial process, the demand of steel mills and chemical plants for oxygen, nitrogen and argon is continuously increased, and the air separation device is further concerned widely. Since gas products are not easily storable and the production of gas is usually constantly fluctuating by the influence of upstream steel or chemical plant production and the influence of electricity prices, air separation plants require frequent load changes to meet production requirements.
In the process of load variation of the air separation device, the air feeding flow rate is usually determined by the oxygen demand, but the air feeding flow rate is not in a linear relation with the oxygen product flow rate when the load varies, the influence factors are more, and particularly in a dynamic system, a corresponding target value of the air feeding flow rate for stabilizing the system is difficult to find through a single variable of the oxygen flow rate. Precise control of the air feed rate is therefore a prerequisite to ensure stable production of the air separation plant during variable loads.
Large air separation companies all have an internal air compressor flow regression relationship. However, the domestic air separation device still relies on operator experience to set the air compressor flow, the device is not easy to be stable and fluctuation can cause unnecessary energy consumption, some plants adjust the air feeding flow by constructing the linear relation between the oxygen flow and the air feeding flow, the fitting degree is low, and the device is not easy to be stable.
Disclosure of Invention
Aiming at the technical defects, the invention discloses a method for controlling the air feeding amount in the automatic load changing process of an air separation device. The invention aims to provide a method for controlling the air feeding amount in the automatic load changing process of an air separation unit, and aims to solve the problems that the conventional air separation unit is not easy to stabilize and has high energy consumption in the load changing process.
The technical scheme adopted by the invention for solving the technical problems is as follows: a method for controlling air feeding amount in an automatic load changing process of an air separation unit comprises the following steps:
the method comprises the following steps: acquiring monitoring information of an air separation device;
step two: obtaining a neural network model which outputs air feeding quantity through a neural network according to the obtained monitoring information;
step three: taking the current value of the monitoring information as an input value of a neural network model to obtain a calculated value of the air flow;
step four: and multiplying the difference value between the calculated value and the current value of the air flow by a coefficient function to obtain an incremental value of the air flow, adding the current value of the air flow to the incremental value to obtain a target value of the air feeding flow, and feeding the target value to a controller to realize the control of the air feeding flow in the variable-load process of the air separation device.
The monitoring information includes: oxygen flow, argon content of argon fraction, oxygen purity, flow of expanded air to the upper tower, nitrogen flow, flow of waste nitrogen and opening degree of a regulating valve for feeding liquid nitrogen to the upper tower.
The target value of the air feed flow rate is obtained by the following formula:
FAirT＝(FAirC-FAir)×f(|FO2T-FO2|)+FAir
wherein, FAirTAs a target value of the air feed flow, FAirCCalculated for air flow, FAirIs the current value of air flow, FO2TIs the target value of oxygen flow, FO2For the current value of the oxygen flow, f is a coefficient function with respect to the absolute value of the difference between the current value of the oxygen flow and the target value of the oxygen flow.
The coefficient function is:
f(x)＝1-ekx
wherein x represents the absolute value of the difference between the target value and the current value of the oxygen flow rate; k is a coefficient
The invention has the following beneficial effects and advantages:
1. the invention can make the air separation device reach a stable state quickly in the process of changing load, and all parameters meet the quality requirement.
2. The control method provided by the invention can be used for inhibiting frequent fluctuation of the air feeding flow of the air separation device and reducing the power consumption of the air compressor.
Drawings
FIG. 1 is a schematic diagram of the construction of an air feed quantity neural network model according to the present invention;
FIG. 2 is a logic diagram of the air feed flow control method in the air separation plant during the variable load process of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples.
The method for controlling the air feeding amount in the automatic load changing process of the air separation device comprises the following steps:
the method comprises the following steps: and obtaining variables such as oxygen flow, argon content of argon fraction, oxygen purity, flow of expanded air entering the upper tower, nitrogen flow, flow of waste nitrogen, opening degree of a regulating valve of liquid nitrogen entering the upper tower and the like of the air separation device.
Step two: from the obtained variables, a computational model of the air feed rate was fitted by a neural network, as shown in fig. 1.
Step three: and taking the target value of the oxygen flow and the current values of variables such as the argon content of the argon fraction, the oxygen purity, the flow of the expanded air entering the upper tower, the nitrogen flow, the waste nitrogen flow and the opening degree of a regulating valve of the liquid nitrogen entering the upper tower as the input values of the established calculation model of the air feeding quantity to obtain the calculated value of the air flow.
Step four: the difference between the calculated and current values of the air flow is multiplied by a coefficient function as the incremental value of the air flow, and this incremental value plus the current value of the air flow is the target value of the air feed flow, as shown in fig. 2. The expression is as follows:
FAirT＝(FAirC-FAir)×f(|FO2T-FO2|)+FAir
wherein: fAirTIs an air feed flow target value; fAirCFor air flow calculationA value; fAirIs the current value of the air flow; fO2TIs the target value of the oxygen flow; fO2Is the current value of the oxygen flow.
f is a coefficient function of the absolute value of the difference between the current oxygen flow rate and the target oxygen flow rate, and the expression is:
f(x)＝1-ekx
wherein: x is the absolute value of the difference between the target value and the current value of the oxygen flow; k is coefficient, and can be set according to system characteristics, and can be-0.0106. When the deviation value of the oxygen flow is small, the output value of the coefficient function is close to 0, and when the deviation is large, the output value of the function is 1, and the function can reduce the fluctuation of the target value of the air flow.
In this embodiment, when the target flow rate of oxygen changes, a calculated value of the air feeding amount is calculated through a neural network model by combining variables such as the argon content of an argon fraction, the purity of oxygen, the tower feeding flow rate of expanded air, the nitrogen flow rate, the waste nitrogen flow rate, the opening degree of a regulating valve of liquid nitrogen feeding to the tower, and the like, a target value of the air feeding amount is calculated through the incremental progressive algorithm, and is sent to a controller, and the controller outputs a control variable to an air separation device, so that the control of the air feeding amount of the air separation device in an automatic load changing process is realized.
Claims (4)
1. A method for controlling air feeding amount in an automatic load changing process of an air separation unit is characterized by comprising the following steps:
the method comprises the following steps: acquiring monitoring information of an air separation device;
step two: obtaining a neural network model which outputs air feeding quantity through a neural network according to the obtained monitoring information;
step three: taking the current value of the monitoring information as an input value of a neural network model to obtain a calculated value of the air flow;
step four: and multiplying the difference value between the calculated value and the current value of the air flow by a coefficient function to obtain an incremental value of the air flow, adding the current value of the air flow to the incremental value to obtain a target value of the air feeding flow, and feeding the target value to a controller to realize the control of the air feeding flow in the variable-load process of the air separation device.
2. The method for controlling the air feeding amount in the automatic variable load process of the air separation plant according to claim 1, wherein the monitoring information comprises: oxygen flow, argon content of argon fraction, oxygen purity, flow of expanded air to the upper tower, nitrogen flow, flow of waste nitrogen and opening degree of a regulating valve for feeding liquid nitrogen to the upper tower.
3. The method for controlling the air feeding quantity in the automatic variable load process of the air separation plant according to claim 1, characterized in that the target value of the air feeding quantity is obtained by the following formula:
FAirT＝(FAirC-FAir)×f(|FO2T-FO2|)+FAir
wherein, FAirTAs a target value of the air feed flow, FAirCCalculated for air flow, FAirIs the current value of air flow, FO2TIs the target value of oxygen flow, FO2For the current value of the oxygen flow, f is a coefficient function with respect to the absolute value of the difference between the current value of the oxygen flow and the target value of the oxygen flow.
4. A method for controlling the air feeding quantity in the automatic variable load process of an air separation plant according to claim 1 or 3, characterized in that the coefficient function is:
f(x)＝1-ekx
wherein x represents the absolute value of the difference between the target value and the current value of the oxygen flow rate; k is a coefficient.
Priority Applications (1)
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| CN201810600952.5A CN110595153A (en) | 2018-06-12 | 2018-06-12 | Control method for air feeding amount in automatic load changing process of air separation device |
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| CN201810600952.5A CN110595153A (en) | 2018-06-12 | 2018-06-12 | Control method for air feeding amount in automatic load changing process of air separation device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114484263A (en) * | 2022-01-07 | 2022-05-13 | 首钢京唐钢铁联合有限责任公司 | Automatic load changing method and system for nitrogen-oxygen liquefaction device |
| WO2022157379A1 (en) * | 2021-01-25 | 2022-07-28 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Method and device for separating air by cryogenic distillation |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5557549A (en) * | 1992-09-28 | 1996-09-17 | Praxair Technology, Inc. | Knowledge based diagnostic advisory system and method for an air separation plant |
| CN102520615A (en) * | 2011-12-28 | 2012-06-27 | 东方电气集团东方汽轮机有限公司 | Automatic load-variable multi-variable control method for air separation device |
| CN106288654A (en) * | 2016-07-27 | 2017-01-04 | 杭州杭氧股份有限公司 | A kind of quick load change optimal control method of oxygen nitrogen rectification external compression air separation plant |
| CN107525348A (en) * | 2017-07-19 | 2017-12-29 | 浙江智海化工设备工程有限公司 | A kind of multivariable predicting control method for air separation unit |
-
2018
- 2018-06-12 CN CN201810600952.5A patent/CN110595153A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5557549A (en) * | 1992-09-28 | 1996-09-17 | Praxair Technology, Inc. | Knowledge based diagnostic advisory system and method for an air separation plant |
| CN102520615A (en) * | 2011-12-28 | 2012-06-27 | 东方电气集团东方汽轮机有限公司 | Automatic load-variable multi-variable control method for air separation device |
| CN106288654A (en) * | 2016-07-27 | 2017-01-04 | 杭州杭氧股份有限公司 | A kind of quick load change optimal control method of oxygen nitrogen rectification external compression air separation plant |
| CN107525348A (en) * | 2017-07-19 | 2017-12-29 | 浙江智海化工设备工程有限公司 | A kind of multivariable predicting control method for air separation unit |
Non-Patent Citations (2)
| Title |
|---|
| 余守志: "《科学技术研究及进展》", 31 August 2005, 中央编译出版社 * |
| 郝磊: "带自动变负荷功能大型制氧机组控制系统的设计与实现", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022157379A1 (en) * | 2021-01-25 | 2022-07-28 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Method and device for separating air by cryogenic distillation |
| FR3119226A1 (en) * | 2021-01-25 | 2022-07-29 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation De | METHOD AND APPARATUS FOR AIR SEPARATION BY CRYOGENIC DISTILLATION |
| CN114484263A (en) * | 2022-01-07 | 2022-05-13 | 首钢京唐钢铁联合有限责任公司 | Automatic load changing method and system for nitrogen-oxygen liquefaction device |
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Application publication date: 20191220 |
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