阅读说明：本技术 一种甲醇精馏装置自动加减负荷智能控制方法 (Automatic load increasing and decreasing intelligent control method for methanol rectification device ) 是由 蒋弟勇 黄涛 黄见东 张小娟 傅利才 王绍贵 辜凯德 汪国瑜 刘鑑 涂洪斌 刘富 于 2021-11-03 设计创作，主要内容包括：本发明属于化工技术领域,公开了一种甲醇精馏装置自动加减负荷智能控制方法。包含：通过智能控制系统的DCS系统获取预精馏塔、加压塔、常压塔和回收塔中各温度点的实时温度；将上述实时温度通过压力矫正温度软测量仪矫正后得到校正温度；在操作界面设定预精馏塔、加压塔、常压塔和回收塔的上述校正温度和第一参数；以及智能控制系统根据设定的校正温度进行预精馏塔、加压塔、常压塔和回收塔的第二参数设定,通过DCS系统实现对第二参数的控制。克服了源于操作员和DCS系统本身基于反馈的控制方式的滞后或者过度调节而引起的系统波动和能量浪费的问题,同时实现了无人智能化操作,甲醇精馏装置在加减负荷过程中系统各关键温度控制点始终保持稳定运行。(The invention belongs to the technical field of chemical industry, and discloses an automatic load increasing and decreasing intelligent control method for a methanol rectification device. Comprises the following steps: acquiring real-time temperatures of various temperature points in a pre-rectifying tower, a pressurizing tower, an atmospheric tower and a recovery tower through a DCS (distributed control system) of an intelligent control system; correcting the real-time temperature by a pressure correction temperature soft measuring instrument to obtain a corrected temperature; setting the correction temperatures and the first parameters of the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower on an operation interface; and the intelligent control system sets second parameters of the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower according to the set correction temperature, and the DCS system is used for controlling the second parameters. The problems of system fluctuation and energy waste caused by lag or over-adjustment of feedback-based control modes of operators and a DCS are solved, meanwhile, unmanned intelligent operation is realized, and all key temperature control points of the system are always kept to stably operate in the process of load increase and reduction of the methanol rectifying device.)

1. An automatic load increasing and decreasing intelligent control method for a methanol rectification device is characterized by comprising the following steps:

acquiring real-time temperatures of various temperature points in a pre-rectifying tower, a pressurizing tower, an atmospheric tower and a recovery tower through a DCS (distributed control system) of an intelligent control system;

correcting the real-time temperature by a pressure correction temperature soft measuring instrument to obtain a corrected temperature;

setting the correction temperatures and the first parameters of the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower on an operation interface; and

and the intelligent control system sets second parameters of the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower according to the set correction temperature, and the DCS is used for controlling the second parameters.

2. The intelligent control method according to claim 1, wherein the intelligent control system comprises a predictive control model, and the predictive control model can read parameter information of the DCS and store the parameter information in an intelligent control system database.

3. The intelligent control method according to claim 2, wherein information is exchanged between the intelligent control system and the DCS system through an OPC server.

4. The intelligent control method according to claim 2, wherein the predictive control model is Aspen DMCplus multivariable model predictive control.

5. The intelligent control method according to claim 1, wherein the first parameter comprises pre-rectification column crude methanol feed, pressurized column feed, atmospheric column kettle level.

6. The intelligent control method according to claim 1, wherein the corrected temperatures set for the pre-rectifying tower, the pressurized tower, the atmospheric tower and the recovery tower at the operation interface include a corrected pre-rectifying tower middle temperature, a pre-rectifying tower top temperature, a pre-rectifying tower reflux temperature, a pressurized tower upper temperature, a pressurized tower bottom temperature, an atmospheric tower upper temperature, an atmospheric tower middle temperature, an atmospheric tower bottom temperature, a recovery tower top temperature, a recovery tower middle sensitive temperature, and a recovery tower bottom temperature.

7. The intelligent control method according to claim 1, wherein the second parameter comprises pre-rectification column bottom steam flow, pressurized column atmospheric column reflux, recovery column bottom steam flow.

Technical Field

The invention relates to the technical field of chemical industry, in particular to an automatic load increasing and decreasing intelligent control method for a methanol rectification device.

Background

The four-tower methanol rectification process flow mainly comprises a pre-rectification tower, a pressurizing tower, an atmospheric tower and a recovery tower, wherein the rectification process is a multivariable and strongly coupled complex control process, the actual operation is influenced by various factors, the load adjustment and the load adjustment of a production device are manually operated by operators, the phenomenon of over-regulation or untimely regulation usually occurs, and the production cost of the methanol rectification device is increased by phase change due to the conditions of system parameter fluctuation and the like.

Disclosure of Invention

In order to solve the problems in the background art, the invention provides an intelligent control method for automatic load increase and decrease of a methanol rectification device. The problems of system fluctuation and energy waste caused by lag or over-adjustment of feedback-based control modes of operators and a DCS are solved, meanwhile, unmanned intelligent operation is realized, and all key temperature control points of the system are always kept to stably operate in the process of load increase and reduction of the methanol rectifying device.

In order to achieve the purpose, the invention adopts the technical scheme that:

an automatic load increasing and decreasing intelligent control method for a methanol rectification device comprises the following steps:

acquiring real-time temperatures of various temperature points in a pre-rectifying tower, a pressurizing tower, an atmospheric tower and a recovery tower through a DCS (distributed control system) of an intelligent control system;

correcting the real-time temperature by a pressure correction temperature soft measuring instrument to obtain a corrected temperature;

setting the correction temperatures and the first parameters of the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower on an operation interface; and

and the intelligent control system sets second parameters of the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower according to the set correction temperature, and the DCS is used for controlling the second parameters.

Further, the intelligent control system comprises a predictive control model, and the predictive control model can read parameter information of the DCS and store the parameter information in an intelligent control system database.

Furthermore, information exchange is carried out between the intelligent control system and the DCS through an OPC server.

Further, the predictive control model is Aspen DMCplus multivariable model predictive control.

Further, the first parameters comprise crude methanol feeding amount of the pre-rectifying tower, feeding amount of the pressurizing tower and tower kettle liquid level of the atmospheric tower.

Furthermore, the corrected temperatures of the pre-rectifying tower, the pressurizing tower, the atmospheric tower and the recovery tower are set at the operation interface, wherein the corrected temperatures comprise the corrected middle temperature of the pre-rectifying tower, the top temperature of the pre-rectifying tower, the reflux temperature of the pre-rectifying tower, the upper temperature of the pressurizing tower, the bottom temperature of the pressurizing tower, the upper temperature of the atmospheric tower, the middle temperature of the atmospheric tower, the bottom temperature of the atmospheric tower, the top temperature of the recovery tower, the sensitive temperature of the middle of the recovery tower and the bottom temperature of the recovery tower.

Further, the second parameter comprises the steam flow of the tower kettle of the pre-rectifying tower, the steam flow of the tower kettle of the pressurizing tower, the reflux quantity of the atmospheric tower of the pressurizing tower and the steam flow of the tower kettle of the recovery tower.

Compared with the prior art, the invention has the following beneficial effects:

the invention relates to an intelligent control solution developed based on DMC (dynamic matrix control) system advanced process control technology, which is characterized in that the intelligent control optimization of steam at the bottom of a pressurizing tower and the intelligent control optimization of pressurizing tower reflux are carried out, key control temperature point soft measuring instruments of the pressurizing tower and an atmospheric tower after pressure correction are simultaneously established, the component distribution in the pressurizing tower and the atmospheric tower is accurately reflected through pressure correction temperature, the intelligent controller can respond in an optimal mode and at the fastest speed in the dynamic process of normal load increasing and decreasing of a methanol rectifying device, an operator is replaced by the intelligent controller to operate a methanol rectifying device control system, the problems of system fluctuation and energy waste caused by lag or over-adjustment of the feedback-based control mode of the operator and a DCS system are solved, and meanwhile, unmanned intelligent operation is realized, the methanol rectifying device always keeps stable operation at each key temperature control point of the system in the process of increasing and reducing load.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer.

The first embodiment of the invention is a methanol rectification device automatic load increasing and decreasing intelligent control method, which comprises the following steps:

acquiring real-time temperatures of various temperature points in a pre-rectifying tower, a pressurizing tower, an atmospheric tower and a recovery tower through a DCS (distributed control system) of an intelligent control system;

correcting the real-time temperature by a pressure correction temperature soft measuring instrument to obtain a corrected temperature;

setting the correction temperatures and the first parameters of the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower on an operation interface; and

and the intelligent control system sets second parameters of the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower according to the set correction temperature, and the DCS is used for controlling the second parameters.

In order to accurately control the distribution of components in the tower, modeling is carried out on the distribution of the components in the tower, a pressure correction temperature soft measuring instrument is established, so that the temperature after pressure correction can really represent the component composition of temperature measuring points, and the temperature points for pressure correction comprise key temperature measuring points such as the temperature of the bottom of a pre-tower, the sensitive temperature of a pressurizing tower, the sensitive temperature of an atmospheric tower, the temperature of the bottom of the atmospheric tower, the temperature of the top of a recovery tower, the temperature of the bottom of the recovery tower and the like, thereby realizing the control of the distribution profile of the components in each tower on the basis, ensuring that the fluctuation can not occur when the load changes, and realizing the stable control of the system in the dynamic process of automatically increasing and reducing the load.

The intelligent control system of the invention exchanges information with a methanol rectification device DCS through an OPC server, the DCS reads and stores real-time running data of operation variables and control variables, the intelligent control system reads the information through the OPC server and stores the information in an intelligent control system database, and the intelligent control system calculates corrected temperature according to the read data and a pressure correction temperature soft measurement model and displays the temperature on a special operation picture of the intelligent control system.

The intelligent control system adopts a predictive control model, when the intelligent control system is put into use, DCS operation variable and control variable information are read and stored in an intelligent control system database, the system calculates the heat quantity required by the system corresponding to the current crude methanol feeding through the model, the tower kettle steam quantity and the pressure tower and normal pressure tower reflux quantity required by a pre-rectifying tower, a pressure tower and a recovery tower at corresponding moments are obtained, and the temperature of each tower is close to the target value set by the intelligent control system.

And according to the output values of the operation variables, obtaining actual values of the temperatures of the towers, continuously reading the actual values by the intelligent control system through the DCS and the OPC server, storing the actual values in a database, comparing the actual values of the DCS with the calculated values of the intelligent control system to obtain correction data, and providing the correction data serving as feedback information for the intelligent control system. The intelligent controller determines the effect of the changes in the manipulated variables and the feedforward variables on the controlled variables and continues to correct the predicted values. The intelligent controller obtains a series of predicted correction values of each controlled variable in the whole steady-state time according to the calculation result of the prediction model, so that the prediction and calculation of each round can be corrected, the calculated value is close to the actual value, and the prediction control capability of the intelligent control system is realized.

The intelligent control of the load increase and the load decrease of the methanol rectifying device is realized as follows: firstly, the load is increased or decreased according to the load of the methanol rectifying device, and the load change gradient is automatically controlled according to a set model of an intelligent control system, namely, like a manual operation method, the operation means is still steam and reflux of each tower kettle, and the temperature of the tower system is controlled in a stable range with almost no fluctuation through the means.

However, it should be noted that, in order to ensure the safe operation of the methanol rectification production device under the control of the intelligent control system, the control ranges of the operation variables and the controlled variables must be set in the DCS operation system of the methanol rectification device itself, and the control range of the intelligent control system is less than or equal to the set value of the DCS system itself, so that all the safety interlocks of the DCS system are ensured to be effective, and all the output values calculated by the intelligent control system are ensured to be controllable and reliable.

In the working process, the control loop of the original methanol rectifying device cannot be changed, only reasonable and appropriate operation in the dynamic process of load change of the methanol rectifying device is realized, and working condition judgment can be carried out in advance according to the change trend of each parameter, so that the lag adjustment or over adjustment of the original manual operation is overcome, and the automatic and intelligent control of the load increase and reduction of the methanol rectifying device is realized.

In order to better understand the technical solution provided by the present invention, the following describes an intelligent control method provided by applying the above embodiments of the present invention with specific examples.

Example 1

An intelligent control method for automatic load increasing and decreasing of a methanol rectifying device comprises the following specific steps:

the first step is as follows: the intelligent control system reads the temperature of each temperature point in the pre-rectifying tower, the pressurizing tower, the normal pressure tower and the recovery tower through the DCS, obtains the temperature after pressure correction through the intelligent control system pressure correction temperature soft measuring instrument and displays the temperature on an operation interface of the intelligent control system.

The second step is that: the crude methanol feed to the pre-rectification column was set (gradient change), and the pre-rectification column, the pressure column, the atmospheric column, and the recovery column were set at the same time (the temperature was calculated by a soft meter after pressure correction) on the operation interface of the intelligent control system, as shown in table 1.

TABLE 1

。

The third step: the intelligent control system sets the steam flow of the pre-rectifying tower kettle, the steam flow of the pressurizing tower kettle, the reflux quantity of the pressurizing tower atmospheric tower and the steam flow of the recovery tower kettle according to temperature setting and crude methanol feeding, controls the steam flow of the pre-rectifying tower kettle, the steam flow of the pressurizing tower kettle, the reflux quantity of the pressurizing tower atmospheric tower and the steam flow of the recovery tower kettle of the methanol rectifying device through DCS, controls the operation variable within the set range, and enables the methanol rectifying device with control variable parameters such as tower temperature and the like to be still in a stable state in the dynamic process of load increasing and reducing. The list of manipulated variables is shown in table 2.

TABLE 2

。

The feeding of the pre-rectifying tower, the feeding amount of the pressurizing tower and the control range of the operating variable are set in the DCS, and the intelligent control system sets the control range of the operating variable according to the set range of the DCS (generally, the control range of the operating variable of the intelligent control system is less than or equal to the setting of the DCS so as to ensure the safe operation of the system).

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.