阅读说明：本技术 一种蒸馏塔顶工艺防腐自动调控系统 (Automatic regulating and controlling system for corrosion prevention of distillation tower top process ) 是由 张艳玲 韩磊 牛鲁娜 兰正贵 于 2018-06-06 设计创作，主要内容包括：本发明提供了一种蒸馏塔顶工艺防腐自动调控系统,包括数据采集系统、自动注水系统、自动注剂系统和控制系统,数据采集系统、自动注水系统和自动注剂系统分别与控制系统相连,数据采集系统包括在线测量系统和数据接口获取系统,在线测量系统包括在线PH计、在线氯离子测定仪和在线铁离子含量测量仪,实现PH值、氯离子及铁离子的实时在线测量；数据接口获取系统包括MES工艺操作数据、LIMS分析化验数据、在线腐蚀监测数据、腐蚀模型计算数据和定点测厚数据在内的其他离线输入数据进行自动获取,存储和集中管理；数据采集系统将采集的数据发送给控制系统,控制系统控制自动注水系统和自动注剂系统进行注水和注剂。(The invention provides an automatic regulating and controlling system for corrosion prevention of a distillation tower top process, which comprises a data acquisition system, an automatic water injection system, an automatic agent injection system and a control system, wherein the data acquisition system, the automatic water injection system and the automatic agent injection system are respectively connected with the control system; the data interface acquisition system comprises MES process operation data, LIMS analysis and assay data, online corrosion monitoring data, corrosion model calculation data and other offline input data including fixed point thickness measurement data for automatic acquisition, storage and centralized management; the data acquisition system sends the acquired data to the control system, and the control system controls the automatic water injection system and the automatic agent injection system to inject water and agent.)

1. The distillation tower top process anticorrosion automatic regulation and control system is characterized by comprising a data acquisition system, an automatic water injection system, an automatic agent injection system and a control system, wherein the data acquisition system, the automatic water injection system and the automatic agent injection system are respectively connected with the control system; the data interface acquisition system comprises MES process operation data, LIMS analysis and assay data, online corrosion monitoring data, corrosion model calculation data and fixed point thickness measurement data; the data acquisition system sends the acquired data to the control system, and the control system controls the automatic agent injection system and the automatic water injection system to inject water and agent.

2. The distillation tower top process corrosion prevention automatic regulation and control system according to claim 1, wherein the automatic agent injection system comprises an agent injection tank, an agent injection pump, an automatic neutralizer injection control system, an automatic corrosion inhibitor injection control system and an automatic alkali injection control system.

3. The distillation tower top process corrosion prevention automatic regulation and control system according to claim 2, wherein the automatic neutralizer injection control system controls neutralizer injection amount based on pH value measured by an on-line pH meter.

4. the automatic corrosion control system for distillation tower top process according to claim 2, wherein the automatic neutralizer injection control system controls neutralizer injection amount by establishing thermodynamic equilibrium model of the tower top system containing electrolyte.

5. The automatic distillation tower top process corrosion prevention regulation and control system according to claim 2, wherein the automatic corrosion inhibitor injection control system controls the injection corrosion inhibitor amount based on the iron ion content measured by the online iron ion content measuring instrument.

6. The automatic regulating and controlling system for corrosion prevention of the distillation tower top process according to claim 2, wherein the automatic corrosion inhibitor injection control system controls the injection amount of corrosion inhibitor through online corrosion monitoring data.

7. The automatic regulating and controlling system for corrosion prevention of the distillation tower top process according to claim 2, wherein the automatic alkali injection control system regulates and controls the alkali injection amount according to chloride ions measured by an online chloride ion tester or customer requirements.

8. The automatic distillation tower top process corrosion prevention regulation and control system as claimed in claim 1, wherein the automatic water injection system controls water injection amount through MES process operation data and LIMS analysis and test data.

9. The automatic distillation tower top process corrosion prevention regulation and control system according to claim 8, wherein the water injection amount in the automatic water injection system is used for calculating the water injection amount required by 20-50% of water injection and still keeping the water in a liquid state according to the MES process operation data and the system pressure, temperature, material flow and composition in LIMS analysis and test data so as to regulate the automatic regulation and control of tower top process measures.

10. The distillation tower top process anticorrosion automatic regulation and control system according to claim 8 or the above, wherein the theoretical water injection amount in the automatic water injection system is as follows:

WhereinIs the saturated vapor pressure of water, and the unit is MPa;

A＝θ²+n₁θ+n₂

B＝n₃θ²+n₄θ+n₅

C＝n₆θ²+n₇θ+n₈

Is the saturation temperature of water in K;

n₁Is 0.11670521452767X 10⁴，n₂is-0.72421316703206 x 10⁶，n₃Is-0.17073846940092 x 10²，n₄Is 0.12020824702470X 10⁵，n₅Is-0.32325550322333 x 10⁷，n₆Is 0.14915108613530X 10²，n₇Is-0.48232657361591 x 10⁴，n₈Is 0.40511340542050×10⁶，n₉Is-0.23855557567849, n₁₀is 0.65017534844798X 10³。

Technical Field

The invention relates to the field of distillation tower top automatic control, in particular to an automatic distillation tower top process anticorrosion regulating and controlling system.

Background

Along with the deterioration of domestic crude oil, the low-temperature corrosion of a distillation tower top system is very prominent in recent years, and the corrosion is a common problem of domestic oil refining enterprises. Mainly manifested in the top of distillation tower (including top circulation), catalytic fractionating tower, coking fractionating tower, most typically dew point corrosion and ammonium salt corrosion of fractionating tower top system such as atmospheric and vacuum distillation tower, and some refineries even have cases of corrosion perforation of tower wall at the top of atmospheric tower. The problem of low-temperature corrosion of a fractionating tower top system is imminent, and the problem becomes a prominent problem influencing the safe long-period operation of an oil refining device. For the control of the low-temperature corrosion of the tower top system, the upgrading by only depending on materials is usually done with half the effort, and the good process corrosion prevention is the key for solving the problems. At home and abroad, the refinery generally adopts 'one-removing-four-injection' process anticorrosion measures, namely electric desalting, water injection, corrosion inhibitor injection, neutralizer injection and alkali injection, and the anticorrosion injection dosage adjustment of the domestic atmospheric pressure reduction device is all originally manually controlled. Because the property of the crude oil is changed continuously, the analysis frequency is low and lags behind, the manual injection agent adjustment cannot keep up with the actual corrosion environment, and the method is an important factor influencing the anticorrosion effect of the process. Experience has shown that 90% of the corrosion occurs 10% of the time, so it is important and urgent to monitor the corrosion protection in real time and automatically adjust the injection agent. CN103420470A 'an automatic control system for pH value of process water medium of oil refining device', realizes automatic adjustment of pH value of water system, but does not consider integrally from the aspect of corrosion prevention of tower top process, and realizes regulation and control of corrosion inhibitor injection, neutralizer and alkali.

disclosure of Invention

Aiming at the technical problems, the invention provides an automatic regulating and controlling system for the corrosion prevention of a distillation tower top process, which is used for improving the corrosion prevention effect of the tower top process and realizing the real-time online analysis of the pH value, chloride ions and iron ions of the tower top; realizes the on-line continuous real-time automatic regulation and control of the neutralizer, the corrosion inhibitor and the alkali injection.

The invention adopts the following technical scheme:

An automatic corrosion prevention regulating and controlling system for a distillation tower top process comprises a data acquisition system, an automatic water injection system, an automatic agent injection system and a control system, wherein the data acquisition system, the automatic water injection system and the automatic agent injection system are respectively connected with the control system; the data interface acquisition system comprises MES process operation data, LIMS analysis and assay data, online corrosion monitoring data, corrosion model calculation data and fixed point thickness measurement data; the data acquisition system sends the acquired data to the control system, and the control system controls the automatic water injection system and the automatic agent injection system to inject water and agent.

Preferably, the automatic agent injection system comprises an agent injection tank, an agent injection pump, an automatic neutralizer injection control system, an automatic corrosion inhibitor injection control system and an automatic alkali injection control system.

Preferably, the automatic neutralizer injection control system controls the amount of neutralizer injected based on the PH measured by the in-line PH meter.

Preferably, the automatic neutralizer injection control system controls neutralizer injection by establishing a thermodynamic equilibrium model of the overhead system containing electrolyte.

Preferably, the automatic corrosion inhibitor injection control system controls the injection corrosion inhibitor amount based on the iron ion content measured by the online iron ion content measuring instrument.

Preferably, the automatic corrosion inhibitor injection control system controls the corrosion inhibitor injection amount through online corrosion monitoring data.

Preferably, the automatic alkali injection control system controls the alkali injection amount through the chlorine ions measured by an online chlorine ion measuring instrument or the adjustment of customer requirements.

Preferably, the automatic water injection system controls the water injection amount through MES process operation data and LIMS analysis assay data.

Preferably, the water injection amount in the automatic water injection system is adjusted according to the water injection amount required by the MES process operation data and the LIMS analysis test data to calculate that 20-50% of water injection is still kept in a liquid state according to the system pressure, temperature, material flow and composition.

Preferably, the theoretical water injection amount in the automatic water injection system is as follows:

Whereinis the saturated vapor pressure of water, and the unit is MPa;

A＝θ²+n₁θ+n₂

B＝n₃θ²+n₄θ+n₅

C＝n₆θ²+n₇θ+n₈

Is the saturation temperature of water in K;

n₁Is 0.11670521452767X 10⁴，n₂is-0.72421316703206 x 10⁶，n₃is-0.17073846940092 x 10²，n₄Is 0.12020824702470X 10⁵，n₅Is-0.32325550322333 x 10⁷，n₆is 0.14915108613530X 10²，n₇Is-0.48232657361591 x 10⁴，n₈Is 0.40511340542050X 10⁶，n₉Is-0.23855557567849, n₁₀Is 0.65017534844798X 10³。

The control logic is embedded into a control system, and the pressure, the temperature, the material flow and the composition of the system are obtained through a data acquisition system, so that the calculation of the water injection amount is realized, and the automatic addition of water injection is finally realized through a water injection pump.

The invention has the beneficial effects that:

The corrosion key parameters are monitored in real time, the injection amount is adjusted in time, the process corrosion prevention effect is greatly improved, the problem of improving the process corrosion prevention effect of the tower top is solved, and the real-time online analysis of the PH value, chloride ions and iron ions of the tower top is realized; the on-line continuous real-time automatic regulation and control of the neutralizer, the corrosion inhibitor and the alkali injection are realized, the corrosion prevention is monitored in real time, and the water injection and the agent injection are automatically regulated; the corrosion prevention effect of the process is prevented from being influenced by the reasons that the property of the crude oil is continuously changed, the analysis frequency is low, the analysis frequency is lagged, the manual injection agent adjustment cannot follow the actual corrosion environment, and the like.

drawings

FIG. 1 is an overall frame diagram of an automatic corrosion control system for a distillation tower top process.

FIG. 2 is a schematic diagram of the implementation process of the distillation tower top process corrosion prevention automatic regulation.

Detailed Description

The invention is described in detail below with reference to the accompanying drawings:

With reference to fig. 1 and 2, an automatic control system for corrosion prevention of a distillation tower top process comprises a data acquisition system, an automatic water injection system, an automatic agent injection system and a control system, wherein the data acquisition system, the automatic water injection system and the automatic agent injection system are respectively connected with the control system; the data interface acquisition system comprises MES process operation data, LIMS analysis and assay data, online corrosion monitoring data, corrosion model calculation data and other offline input data including fixed point thickness measurement data for automatic acquisition, storage and centralized management; the data acquisition system sends the acquired data to the control system, and the control system controls the automatic water injection system and the automatic agent injection system to inject water and agent.

1. Regulating and controlling the injection:

The automatic agent injection system comprises an agent injection tank, an agent injection pump, an automatic neutralizer injection control system, an automatic corrosion inhibitor injection control system and an automatic alkali injection control system.

The automatic neutralizer injection control system controls the injection amount of the neutralizer based on the pH value measured by the online pH meter. A thermodynamic equilibrium model of the overhead system containing electrolyte can also be established to control the injection amount of the neutralizing agent.

The automatic corrosion inhibitor injection control system controls the injection corrosion inhibitor dosage based on the iron ion content measured by the online iron ion content measuring instrument and the online corrosion monitoring data.

the automatic alkali injection control system adjusts and controls the alkali injection amount through the chloride ions measured by the online chloride ion measuring instrument or the requirement of a customer.

An online measuring system, namely an online PH meter, an online chloride ion tester and an online iron ion content measuring instrument, is arranged at the water drum position of a condensing tank on the top of the fractionating tower. The online measurement system transmits real-time measurement data to the control cabinet through the transmitter, the control cabinet is connected with the DCS system, and an operator can monitor data change in real time.

In the implementation process, the change of the pH value is linked with an injection system of a neutralizer, the iron ions and the corrosion rate are linked with the injection of a corrosion inhibitor, the chloride ions are linked with the injection of alkali, the data measured by a measuring system is compared with the set optimal regulating value through a control system to obtain deviation, the deviation is fed back to an injection system, the frequency output of a variable frequency controller is continuously regulated through a PID algorithm in the injection controller, and the injection amount of the neutralizer, the corrosion inhibitor and the alkali liquor is regulated. The whole system forms closed-loop control, and ensures the stable injection of on-site neutralizer, corrosion inhibitor and alkali.

Some enterprises do not install an online PH meter, an online chloride ion tester and an online iron ion content measuring instrument, automatically acquire MES process operation data, LIMS analysis and assay data, online corrosion monitoring data, corrosion model calculation data and other offline input data including fixed-point thickness measurement data by using a data interface of a data interface acquisition system, and control the injection amount of a neutralizer, a corrosion inhibitor and alkali liquor according to the same logic. Wherein the pH value control range is as follows: 5.5-7.5 (when organic amine is injected), 7.0-9.0 (when ammonia is injected) 6.5-8.0 (organic amine + ammonia); iron ion control range: less than or equal to 3 (mg/L). The control range of the Cl < - > content is less than or equal to 30 (mg/L); the average corrosion rate control range is less than or equal to 0.2 (mm/a).

2. regulating and controlling water injection:

And the water injection amount in the automatic water injection system is automatically regulated and controlled according to the water injection amount required by adjusting tower top process measures for calculating 20-50% of water injection and still keeping the water injection amount in a liquid state according to MES process operation data and system pressure, temperature, material flow and composition in LIMS analysis and test data.

The theoretical water injection amount in the automatic water injection system is as follows:

WhereinIs the saturated vapor pressure of water, and the unit is MPa;

A＝θ²+n₁θ+n₂

B＝n₃θ²+n₄θ+n₅

C＝n₆θ²+n₇θ+n₈

Is the saturation temperature of water in K;

n₁is 0.11670521452767X 10⁴，n₂Is-0.72421316703206 x 10⁶，n₃Is-0.17073846940092 x 10²，n₄Is 0.12020824702470X 10⁵，n₅Is-0.32325550322333 x 10⁷，n₆Is 0.14915108613530X 10²，n₇Is-0.48232657361591 x 10⁴，n₈is 0.40511340542050X 10⁶，n₉Is-0.23855557567849, n₁₀Is 0.65017534844798X 10³。

The control logic is embedded into a control system, and the pressure, the temperature, the material flow and the composition of the system are obtained through a data acquisition system, so that the calculation of the water injection amount is realized, and the automatic addition of water injection is finally realized through a water injection pump.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.