阅读说明：本技术 一种裂解炉自动投退料对切控制方法、存储介质及系统 (Splitting control method, storage medium and system for automatic feeding and returning material splitting of cracking furnace ) 是由 张小锋 董玉玺 李柏林 田宇 张宏科 于 2021-09-09 设计创作，主要内容包括：本发明提供一种裂解炉自动投退料对切控制方法、存储介质及系统,其中的方法包括：采集第一裂解炉和第二裂解炉的系统运行参数,所述第一裂解炉和所述第二裂解炉为对切的两台裂解炉；若所述第一裂解炉和所述第二裂解炉的系统运行参数是否满足对切条件,则控制所述第一裂解炉的投料进程和所述第二裂解炉的退料进程,使总体进料量保持平稳。本发明的方案,通过协同控制的方法控制投退料过程中两台裂解炉各自的进程,从而使总体进料量保持平稳,减少对下游的影响。(The invention provides an automatic feeding and returning material bisection control method, a storage medium and a system for a cracking furnace, wherein the method comprises the following steps: collecting system operation parameters of a first cracking furnace and a second cracking furnace, wherein the first cracking furnace and the second cracking furnace are two split cracking furnaces; and if the system operation parameters of the first cracking furnace and the second cracking furnace meet the bisection condition, controlling the feeding process of the first cracking furnace and the material returning process of the second cracking furnace to keep the total feeding amount stable. According to the scheme provided by the invention, the respective processes of the two cracking furnaces in the feeding and returning process are controlled by a cooperative control method, so that the total feeding amount is kept stable, and the influence on the downstream is reduced.)

1. An automatic feeding and returning material bisection control method for a cracking furnace is characterized by comprising the following steps:

collecting system operation parameters of a first cracking furnace and a second cracking furnace, wherein the first cracking furnace and the second cracking furnace are two split cracking furnaces;

and if the system operation parameters of the first cracking furnace and the second cracking furnace meet the bisection condition, controlling the feeding process of the first cracking furnace and the material returning process of the second cracking furnace to keep the total feeding amount stable.

2. The automatic feeding and discharging material bisection control method for the cracking furnace as claimed in claim 1, wherein the step of controlling the feeding process of the first cracking furnace and the discharging process of the second cracking furnace further comprises:

and monitoring the running states of the first cracking furnace and the second cracking furnace, and if the running states indicate that the first cracking furnace or the second cracking furnace is abnormal, interrupting the feeding process of the first cracking furnace and the material returning process of the second cracking furnace.

3. The automatic feeding and returning material beveling control method for the cracking furnace as claimed in claim 2, wherein the step of controlling the feeding process of the first cracking furnace comprises the steps of:

adjusting the cracking furnace before feeding: before feeding, controlling the current hearth outlet temperature of the first cracking furnace to be adjusted to the preset hearth outlet temperature at a first set rate;

feeding control at the initial feeding stage: after the first cracking furnace is fed to a certain value, the feeding control valve is adjusted to a controllable valve position;

feeding to a first feeding set value to a feeding target value: controlling the feeding speed and the flow regulation of the diluted steam in the process of respectively increasing the feeding value of the first cracking furnace to a first feeding set value, at least one middle feeding set value and a feeding target value;

adjusting and controlling after the feeding is finished: and after the feeding is finished, adjusting the steam dilution ratio, the hearth outlet temperature deviation value and the hearth outlet temperature value of the steam cascade control of the first cracking furnace, and prompting a feeding finishing signal after the adjustment is finished.

4. The automatic feeding and returning material beveling control method of the cracking furnace as claimed in claim 3, wherein the step of controlling the feeding at the initial feeding stage comprises:

controlling each feeding control valve of a single group of furnace tubes of a first cracking furnace to a first opening value, and waiting for a first set time length;

if the flow of a certain group of furnace tubes is smaller than the minimum controllable flow of the valve, the opening of the group of feeding control valves is increased by a certain opening until the flow of the group of furnace tubes reaches the minimum controllable flow of the valve;

if the flow of a certain group of furnace tubes is greater than or equal to the minimum controllable flow of the valve, judging that the group of feeding control valves is adjusted to the controllable valve position;

after the feeding control valves of all groups of furnace tubes are adjusted to controllable valve positions, each group of feeding control valves is arranged at an automatic position, and a flow cascade control process is put into use.

5. The automatic feeding and returning material beveling control method of the cracking furnace as claimed in claim 4, wherein the step of controlling the feeding to the first feeding set value to the feeding target value comprises:

the first feeding set value is 20%, and at least one middle feeding set value comprises 40%, 60% and 80%; adjusting the feeding load and feeding speed parameters in the feeding process; wherein:

gradually closing the purging steam after the feeding of the first cracking furnace reaches 60%; after the feed is fed to 80%, the flow rate of the dilution steam in the hearth is reduced, so that the ratio of the dilution steam to the feed is 0.3-0.5.

6. The automatic feeding and returning beveling control method for the cracking furnace as claimed in claim 1, wherein the controlling of the returning process of the second cracking furnace comprises:

adjusting the cracking furnace before material returning: collecting the running state of a second cracking furnace, if the running state of the second cracking furnace meets the material returning condition, placing the chain in the bypass state caused by the reduction of the feeding amount in the second cracking furnace, placing the deviation control of the hearth outlet temperature of the second cracking furnace in manual operation, reducing the hearth outlet temperature of the second cracking furnace to the preset material returning temperature at a second cooling rate, and changing the flow control of dilution steam from the cascade control to the automatic flow control and setting the flow control at a fixed value;

and (3) controlling the feeding to a second feeding set value to a material returning target value: controlling the second cracking furnace to perform material returning operation at a set speed, so that the feeding value is adjusted from a second feeding set value to a first intermediate set value; controlling the second cracking furnace to increase the amount of blowing steam and the amount of diluting steam, so that the feeding value is from a first intermediate set value to a second intermediate set value; and controlling the opening value of the feeding control valve of each group of furnace tubes in the second cracking furnace to reduce the feeding value from a second middle set value to 0% after the opening value is used for a set time length, and then closing the feeding control valve of each group of furnace tubes.

7. The automatic feeding and returning material beveling control method for the cracking furnace as claimed in claim 6, wherein the step of controlling the feeding to the second feeding set value to the returning material target value further comprises the following steps:

setting the valve opening degree of a feeding control valve of a single group of furnace tubes in the second cracking furnace to a first negative opening degree value; setting the opening degree of a total feeding electromagnetic valve in a second cracking furnace to a second negative opening value; and closing the feeding electromagnetic cut-off valve in the second cracking furnace, closing the dimethyl disulfide injection valve in the second cracking furnace, closing the online sampling electromagnetic valve, and sending prompt information for switching the operation mode of the cracking furnace.

8. The automatic feeding and discharging material bisection control method for the cracking furnace as claimed in any one of claims 1 to 7, wherein in the step of controlling the feeding process of the first cracking furnace and the discharging process of the second cracking furnace to keep the total feeding amount stable:

the feeding time of the first cracking furnace for completing a certain feeding amount is consistent with the material returning time of the second cracking furnace for completing the same feeding amount; and the deviation value of the total feeding amount does not exceed the set deviation value.

9. A storage medium, wherein the storage medium stores program instructions, and a computer reads the program instructions and executes the automatic feeding and returning material bisection control method of the cracking furnace as claimed in any one of claims 1 to 8.

10. An automatic feeding and returning material beveling control system for a cracking furnace, which is characterized by comprising at least one processor and at least one memory, wherein program instructions are stored in at least one memory, and the program instructions are read by at least one processor to execute the automatic feeding and returning material beveling control method for the cracking furnace according to any one of claims 1-8.

Technical Field

The invention belongs to the technical field of automatic control of cracking furnaces, and particularly relates to an automatic feeding and returning material bisection control method, a storage medium and a system for a cracking furnace.

Background

In the running process of the ethylene device, cracking needs to be switched, a cracking furnace which needs to be burnt at the final running stage is switched into a system, and the cracking furnace which is in a standby state after the burning is finished is switched into a system. In the switching process, a cracking furnace of the switching-in system is used for feeding cracking raw materials for production, and a cracking material return of the switching-out system is offline for preparing scorching.

Generally, two operators are required to independently operate in the feeding and returning processes of the cracking furnaces respectively, and a single cracking furnace is controlled to complete the corresponding process. In the operation process, the feeding and returning speed and the cracking depth of the two cracking furnaces influence the stable operation of subsequent compression, and if the total amount entering a compressor is greatly changed, the compression system can be greatly fluctuated, and the separation system can also be influenced. Especially, the ethylene cracking tends to be large-scale gradually, the production capacity of a single cracking furnace reaches 25 ten thousand tons per year, a 100 ten thousand ton ethylene production device can meet production only by matching 5-6 cracking furnaces, two cracking furnaces are switched, about 20% of the total feeding of the device is switched, operators are not closely matched, and the adjustment is not timely, so that the production fluctuation of the whole device is easily caused.

Disclosure of Invention

The invention aims to solve the technical problem of providing an automatic feeding and returning material splitting control method and system for a cracking furnace, and overcoming the production fluctuation caused by manual operation of cracking furnace switching in the prior art.

Therefore, some embodiments of the present invention provide an automatic feeding and returning material beveling control method for a cracking furnace, including:

collecting system operation parameters of a first cracking furnace and a second cracking furnace, wherein the first cracking furnace and the second cracking furnace are two split cracking furnaces;

and if the system operation parameters of the first cracking furnace and the second cracking furnace meet the bisection condition, controlling the feeding process of the first cracking furnace and the material returning process of the second cracking furnace to keep the total feeding amount stable.

In the method for controlling automatic feeding and returning of a cracking furnace according to some embodiments of the present invention, the step of controlling the feeding process of the first cracking furnace and the returning process of the second cracking furnace further includes:

and monitoring the running states of the first cracking furnace and the second cracking furnace, and if the running states indicate that the first cracking furnace or the second cracking furnace is abnormal, interrupting the feeding process of the first cracking furnace and the material returning process of the second cracking furnace.

In the method for controlling automatic feeding and returning of a cracking furnace according to some embodiments of the present invention, in the step of controlling the feeding process of the first cracking furnace and the returning process of the second cracking furnace, controlling the feeding process of the first cracking furnace includes:

adjusting the cracking furnace before feeding: before feeding, controlling the current hearth outlet temperature of the first cracking furnace to be adjusted to the preset hearth outlet temperature at a first set rate;

feeding control at the initial feeding stage: after the first cracking furnace is fed to a certain value, the feeding control valve is adjusted to a controllable valve position;

feeding to a first feeding set value to a feeding target value: controlling the feeding speed and the flow regulation of the diluted steam in the process of respectively increasing the feeding value of the first cracking furnace to a first feeding set value, at least one middle feeding set value and a feeding target value;

adjusting and controlling after the feeding is finished: and after the feeding is finished, adjusting the steam dilution ratio, the hearth outlet temperature deviation value and the hearth outlet temperature value of the steam cascade control of the first cracking furnace, and prompting a feeding finishing signal after the adjustment is finished.

According to the automatic feeding and returning material beveling control method for the cracking furnace provided by some embodiments of the invention, the feeding control step at the initial feeding stage comprises the following steps:

controlling each feeding control valve of a single group of furnace tubes of a first cracking furnace to a first opening value, and waiting for a first set time length;

if the flow of a certain group of furnace tubes is smaller than the minimum controllable flow of the valve, the opening of the group of feeding control valves is increased by a certain opening until the flow of the group of furnace tubes reaches the minimum controllable flow of the valve;

if the flow of a certain group of furnace tubes is greater than or equal to the minimum controllable flow of the valve, judging that the group of feeding control valves is adjusted to the controllable valve position;

after the feeding control valves of all groups of furnace tubes are adjusted to controllable valve positions, each group of feeding control valves is arranged at an automatic position, and a flow cascade control process is put into use.

According to the automatic feeding and returning material splitting control method for the cracking furnace provided by some embodiments of the invention, the steps from feeding to the first feeding set value to the feeding target value are as follows:

the first feeding set value is 20%, and at least one middle feeding set value comprises 40%, 60% and 80%; adjusting the feeding load and feeding speed parameters in the feeding process; wherein:

gradually closing the purging steam after the feeding of the first cracking furnace reaches 60%; after the feed is fed to 80%, the flow rate of the dilution steam in the hearth is reduced, so that the ratio of the dilution steam to the feed is 0.3-0.5.

In the automatic feeding and returning material beveling control method for the cracking furnace provided by some embodiments of the present invention, controlling the returning process of the second cracking furnace includes:

adjusting the cracking furnace before material returning: collecting the running state of a second cracking furnace, if the running state of the second cracking furnace meets the material returning condition, placing the chain in the bypass state caused by the reduction of the feeding amount in the second cracking furnace, placing the deviation control of the hearth outlet temperature of the second cracking furnace in manual operation, reducing the hearth outlet temperature of the second cracking furnace to the preset material returning temperature at a second cooling rate, and changing the flow control of dilution steam from the cascade control to the automatic flow control and setting the flow control at a fixed value;

and (3) controlling the feeding to a second feeding set value to a material returning target value: controlling the second cracking furnace to perform material returning operation at a set speed, so that the feeding value is adjusted from a second feeding set value to a first intermediate set value; controlling the second cracking furnace to increase the amount of blowing steam and the amount of diluting steam, so that the feeding value is from a first intermediate set value to a second intermediate set value; and controlling the opening value of the feeding control valve of each group of furnace tubes in the second cracking furnace to reduce the feeding value from a second middle set value to 0% after the opening value is used for a set time length, and then closing the feeding control valve of each group of furnace tubes.

The automatic feeding and returning material splitting control method for the cracking furnace provided by some embodiments of the invention further comprises the following steps after the steps of feeding to the second feeding set value and controlling to the returning material target value:

setting the valve opening degree of a feeding control valve of a single group of furnace tubes in the second cracking furnace to a first negative opening degree value; setting the opening degree of a total feeding electromagnetic valve in a second cracking furnace to a second negative opening value; and closing the feeding electromagnetic cut-off valve in the second cracking furnace, closing the dimethyl disulfide injection valve in the second cracking furnace, closing the online sampling electromagnetic valve, and sending prompt information for switching the operation mode of the cracking furnace.

In the method for controlling automatic feeding and returning of the cracking furnace provided by some embodiments of the present invention, a feeding process of the first cracking furnace and a returning process of the second cracking furnace are controlled, so that an overall feeding amount is kept stable:

the feeding time of the first cracking furnace for completing a certain feeding amount is consistent with the material returning time of the second cracking furnace for completing the same feeding amount; and the deviation value of the total feeding amount does not exceed the set deviation value.

The invention provides a storage medium, wherein program instructions are stored in the storage medium, and a computer reads the program instructions and executes the automatic feeding, returning and beveling control method of the cracking furnace.

The invention provides an automatic feeding and returning material bisection control system for a cracking furnace, which comprises at least one processor and at least one memory, wherein program instructions are stored in the at least one memory, and the at least one processor reads the program instructions and then executes the automatic feeding and returning material bisection control method for the cracking furnace.

Compared with the prior art, the technical scheme provided by the invention at least has the following beneficial effects: the respective processes of the two cracking furnaces in the feeding and returning process are controlled by a cooperative control method, so that the total feeding amount is kept stable, and the influence on the downstream is reduced.

Drawings

FIG. 1 is a flow chart of an automatic feeding and returning material beveling control method for a cracking furnace according to an embodiment of the invention;

FIG. 2 is a flow chart of a charge control process according to one embodiment of the present invention;

FIG. 3 is a flow chart of a charging condition determining process according to an embodiment of the present invention;

FIG. 4 is a flow chart of a discharge control process according to an embodiment of the present invention;

FIG. 5 is a flow chart of the control of the furnace feed regulator valve of the batch control process according to an embodiment of the present invention;

FIG. 6 is a flow chart of a portion of a complete dosing control process as described in one embodiment of the present invention;

FIG. 7 is a flow chart of a portion of a complete dosing control process as described in one embodiment of the present invention;

FIGS. 8a-8d are flow charts of the charge bisection control process for cracking furnaces A and B in one embodiment of the present invention;

fig. 9 is a schematic diagram of a hardware structure of an automatic feeding and returning material bisection control system of a cracking furnace according to an embodiment of the invention.

Detailed Description

The embodiments of the present invention will be further described with reference to the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description of the present invention, and do not indicate or imply that the device or assembly referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

The embodiment provides a method for controlling automatic feeding, returning and beveling of a cracking furnace, as shown in fig. 1, the method includes the following steps:

s101: collecting system operation parameters of a first cracking furnace and a second cracking furnace, wherein the first cracking furnace and the second cracking furnace are two split cracking furnaces. This step is performed before switching the cracking furnace. The method comprises the steps of collecting system operation parameters of two opposite splitting cracking furnaces DCS (distributed control system), and monitoring data such as a fuel gas system, a dilution steam generation system, a raw material system and a cracking furnace operation mode of the cracking furnaces to judge whether the two cracking furnaces have opposite splitting conditions at present. Specifically, the method comprises the following steps: the operation parameters comprise the pressure and the temperature of a fuel gas system of a public system, the liquid level of a separation tank, the temperature and the pressure of a dilution steam system; the states of important valves such as SS systems, fuel gas, feeding systems, dilution steam and the like of the two split cracking furnaces, and the information of the temperature, the negative pressure, the operation of a fan, the operation mode of the cracking furnaces and the like of a hearth. The information DCS has records and can directly receive data transmitted by the DCS.

S102: and if the system operation parameters of the first cracking furnace and the second cracking furnace meet the bisection condition, controlling the feeding process of the first cracking furnace and the material returning process of the second cracking furnace to keep the total feeding amount stable. The feeding control logic of the first cracking furnace comprises the control of a feeding valve, the control of dilution steam, the monitoring of cracking furnace abnormity and the like which may appear in the feeding process of the cracking furnace from 0% to 100%, and the material returning control logic comprises the control of a valve, the control of dilution steam, the monitoring of cracking furnace abnormity and the like which may appear in the material returning process of the second cracking furnace from 100% to 0%. The bisection condition comprises a preset parameter threshold value, the related parameter threshold value is stored in the system, and whether the two cracking furnaces meet the bisection condition can be judged according to the comparison between the collected operation parameters and the parameter threshold value.

In the scheme, the respective processes of the two cracking furnaces in the feeding and returning process are controlled by a cooperative control method, so that the total feeding amount is kept stable, the fluctuation of the total feeding amount cannot exceed 5t, preferably is kept below 2t, and the like, and the influence on the downstream is reduced. The control program is used for splitting the cracking furnace in half, the running state of the cracking furnace can be collected in seconds and adjusted at the same time, and the frequency and the precision of adjustment are far higher than those of manual adjustment of an operator. Through the accurate adjustment of the control program, the non-fluctuation bisection of the total feeding amount of the cracking furnace can be realized, the deviation of the total feeding amount can be controlled within 2-5t, and the fluctuation influence of the conventional manual operation on a subsequent compression system is greatly reduced.

In some embodiments, the method for controlling automatic feeding and returning material splitting of a cracking furnace further includes the following steps: and monitoring the running states of the first cracking furnace and the second cracking furnace, and if the running states indicate that the first cracking furnace or the second cracking furnace is abnormal, interrupting the feeding process of the first cracking furnace and the material returning process of the second cracking furnace. Therefore, the cooperative control feeding and returning method in the scheme can also cope with the abnormal conditions of the two cracking furnaces in the feeding and returning period, and can interrupt the process in time when the abnormal conditions are detected to back to the safe state. In the scheme, the system states of the cracking furnaces are monitored in the whole process of the feeding control process and the material returning control process, whether each index exceeds the standard or not is judged, if the operating parameters exceed the range in the feeding and returning process, a pause instruction is sent to the material returning or discharging process of the cracking furnace, the cracking furnace pause information fed back by the control systems of the two cracking furnaces is received in the whole process of cooperative control, and if the feeding or discharging of any cracking furnace is paused, a pause instruction is sent to the other cracking furnace. The logic is used for meeting the requirement of synchronous operation of the two cracking furnaces, and the fluctuation of feeding and returning materials is reduced.

The feeding and returning programs respectively comprise modifiable feeding process control parameters for controlling the feeding and returning speed. In some embodiments, as shown in fig. 2, controlling the charging process of the first cracking furnace comprises:

s201: adjusting the cracking furnace before feeding: before feeding, controlling the current hearth outlet temperature (COT) of the first cracking furnace to be adjusted to the preset hearth outlet temperature at a first set speed. As shown in FIG. 3, in the feeding control process, the first cracking furnace adjusts the cracking furnace to be fed at a certain rate before feeding from the current COT to the feeding preparation COT parameter, wherein X is the allowable COT deviation value, Y is the allowable temperature change rate, T0 is the waiting time, and the above three parameters can be set and modified in the parameter table. The setting of each parameter and the adjustment rate can be predetermined in a calibration mode.

S202: feeding control at the initial feeding stage: after the first cracking furnace is fed to a certain value, the feeding control valve is adjusted to a controllable valve position. In the step, the first cracking furnace adopts small valve position control at the initial feeding stage, and the purpose is to feed the first cracking furnace to a certain value (a value less than 20% of the capacity) so that the feeding control valve can reach a controllable valve position. Specifically, the method can be realized by the following steps: controlling the individual feed control valves of a single set of furnace tubes of the first cracking furnace to a first opening value (e.g., 1%, 3%, etc.) and waiting a first set time period (which may be several minutes); if the flow of a certain group of furnace tubes is smaller than the minimum controllable flow of the valve, the opening of the group of feeding control valves is increased by a certain opening (for example, increased by 1%) until the flow of the group of furnace tubes reaches the minimum controllable flow of the valve; if the flow of a certain group of furnace tubes is greater than or equal to the minimum controllable flow of the valve, judging that the group of feeding control valves is adjusted to the controllable valve position; after the feeding control valves of all groups of furnace tubes are adjusted to controllable valve positions, each group of feeding control valves is arranged at an automatic position, and a flow cascade control process is put into use. In some application scenarios, four feeding regulating valves FV1, FV2, FV3 and FV4 may be set, each time a single group of furnace tube feeding regulating valves FV1/FV2/FV3/FV4 is opened to a certain opening degree (1%), DT1min is waited, the furnace tube feeding flow rate is judged to be greater than the minimum controllable flow rate MINF1t/h of the valve, and if the condition is not met, the opening degree of the group of furnace tube feeding regulating valves continues to be increased by a certain opening degree (1%) and DT1min is waited. If the flow reaches the minimum value and the valve position of the group of feeding regulating valves reaches the controllable valve position, the group of feeding electromagnetic valves are placed at the automatic position and the flow cascade control is applied.

S203: feeding to a first feeding set value to a feeding target value: controlling the feeding speed and the flow regulation of the diluted steam in the process of respectively increasing the feeding value of the first cracking furnace to a first feeding set value, at least one middle feeding set value and a feeding target value; in this step, the first feeding set value is 20%, and at least one intermediate feeding set value comprises 40%, 60% and 80%; adjusting the feeding load and feeding speed parameters in the feeding process; wherein: gradually closing the purging steam after the feeding of the first cracking furnace reaches 60%; after the feed is fed to 80%, the flow rate of the dilution steam in the hearth is reduced, so that the ratio of the dilution steam to the feed is 0.3-0.5. Specifically, the process from the feeding value of 20% to the target value is mainly to control the feeding speed and the flow regulation of the dilution steam in the process of respectively increasing the feeding of the cracking furnace to 20%, 40%, 60%, 80% and the target feeding value (100%). The feeding load and feeding speed parameters can be adjusted, the flow control of the dilution steam is generally started to gradually close the purge steam after the cracking furnace is fed to 60%, the flow of the dilution steam of the hearth is started to reduce after the cracking furnace is fed to 80%, and the proportion of the dilution steam to the feeding is gradually between 0.3 and 0.5.

S204: adjusting and controlling after the feeding is finished: and after the feeding is finished, adjusting the steam dilution ratio, the hearth outlet temperature deviation value and the hearth outlet temperature value of the steam cascade control of the first cracking furnace, and prompting a feeding finishing signal after the adjustment is finished. Namely, the adjustment after the feeding is finished comprises three contents: and (4) performing cascade control on the dilution steam, setting the dilution ratio, performing COT deviation control, adjusting the operation COT of the cracking furnace, and prompting that the feeding is finished after the adjustment is finished.

In some embodiments, as shown in fig. 4, controlling the material return process of the second cracking furnace comprises:

s301: adjusting the cracking furnace before material returning: collecting the running state of the second cracking furnace, if the running state of the second cracking furnace meets the material returning condition, placing the chain in the bypass state caused by the reduction of the feeding amount in the second cracking furnace, placing the deviation control of the hearth outlet temperature of the second cracking furnace in manual mode, reducing the hearth outlet temperature of the second cracking furnace to the preset material returning temperature at a second cooling rate, changing the flow control of the dilution steam from the cascade control to automatic flow control, and setting the flow control at a fixed value.

S302: and (3) controlling the feeding to a second feeding set value to a material returning target value: controlling the second cracking furnace to perform material returning operation at a set speed, so that the feeding value is adjusted from a second feeding set value to a first intermediate set value; controlling the second cracking furnace to increase the amount of blowing steam and the amount of diluting steam, so that the feeding value is from a first intermediate set value to a second intermediate set value; and controlling the opening value of the feeding control valve of each group of furnace tubes in the second cracking furnace to reduce the feeding value from a second middle set value to 0% after the opening value is used for a set time length, and then closing the feeding control valve of each group of furnace tubes. Specifically, in the process of returning from 100% load to X load of the second cracking furnace, the material returning is set to X load (X is more than or equal to 60%) through a cooperative control method, the required time is T minutes, and the material returning operation is carried out on the specified hearth at the speed set in the cooperative control process. And after the returned material is returned from the X load to the Y load (Y is more than or equal to 20%), the material returning of the second cracking furnace is continued, the blowing steam dosage is increased to a DS2 value, the dilution steam dosage is increased to a DS3 value, the over-temperature of the convection section furnace tube is prevented, and the material returning time is kept consistent with the adjusting time of the blowing steam and the dilution steam within the range from the X load to the Y load. And in the process that the second cracking furnace is returned to 0% load from Y% load, a valve position control material returning mode is adopted in consideration of unstable low flow control of a valve. And setting each group of feed regulating valves FV1, FV2, FV3 and FV4 to be used for the same time length, and respectively closing the current opening degrees C1, C2, C3 and C4 to 0 percent opening degree, wherein the material returning of the cracking furnace is finished.

That is, in the material returning process, the operation state of the material returning cracking furnace, including the operation mode, the COT control, the dilution steam control state and the like, is firstly collected, and whether the second cracking furnace meets the material returning condition or not is judged. If the second cracking furnace meets the material returning condition, firstly, the feeding low-flow chain and other chains related to the reduction of the feeding amount are all placed in a bypass state, the COT deviation control is placed in manual operation, the COT of the cracking furnace is reduced to the material returning temperature at a certain cooling rate, the dilution steam flow control is changed from cascade control to automatic flow control, a fixed value is set, and then the material returning command is sent by a cooperative control program to start material returning.

Preferably, the controlling the material returning process of the second cracking furnace further comprises:

s303: setting the valve opening degree of a feeding control valve of a single group of furnace tubes in the second cracking furnace to a first negative opening degree value; setting the opening degree of a total feeding electromagnetic valve in a second cracking furnace to a second negative opening value; and closing the feeding electromagnetic cut-off valve in the second cracking furnace, closing the dimethyl disulfide injection valve in the second cracking furnace, closing the online sampling electromagnetic valve, and sending prompt information for switching the operation mode of the cracking furnace. That is, when the material returning control process of the second cracking furnace controls the designated material returning of the cracking furnace to 0% of load, the opening degree of the single-group feeding control valve is automatically set to be 3% of the opening degree of the total feeding electromagnetic valve, the feeding electromagnetic cut-off valve is closed, the DMDS injection valve is closed, the online sampling electromagnetic valve is closed, and an operator is prompted to switch the operation mode of the cracking furnace on the control panel.

In each scheme of the application, the feeding time for completing a certain feeding amount of the first cracking furnace is consistent with the material returning time for completing the same feeding amount of the second cracking furnace; and the deviation value of the total feeding amount does not exceed the set deviation value. In the concrete implementation: in the process of feeding and returning the materials of the two cracking furnaces, the feeding and returning time of the two cracking furnaces for completing the same feeding amount is kept consistent every time according to the total feeding amount (within the range of 10-20%) of a certain proportion. Therefore, the influence of the switching of the cracking furnace on a subsequent system can be reduced, and the system fluctuation is reduced. And in the cooperative control process, total feeding flow data of the two cracking furnaces can be acquired in the whole process, when the total deviation exceeds a certain value (3-5t), one cracking furnace with the higher feeding or returning speed is suspended for waiting, after the feeding deviation of the two cracking furnaces is less than 2t, the suspended cracking furnace is continuously carried out, and the two cracking furnaces are continuously fed and returned to a set value according to the original process.

The method in the above embodiment of the present invention is further described below by taking a certain 100 ten thousand tons per year domestic ethylene plant as a specific example:

and (4) monitoring whether the two cracking furnaces have switching conditions or not by the system before feeding and returning. The collected operation information of the cracking furnace mainly comprises boiler water supply system operation parameters, raw material supply system operation parameters, fuel gas system operation parameters, dilution steam system operation parameters, the temperature of a hearth of the cracking furnace, negative pressure, operation modes and the like. And when all the information is met, the program judges the standby feeding and returning switching conditions of the cracking furnace, if a certain item is not met, the program automatically pops up a prompt to inform an operator that the item does not meet the switching conditions, the program automatically waits to continuously acquire the information until the conditions are completely met, and the condition of switching is judged to be met. Specific judgment conditions are shown in table 1.

TABLE 1 Condition judgment for feeding and returning

The feeding control process comprises the following steps: the flow cascade control cannot be carried out at the initial feeding stage due to the controllability of the valve, the valve opening is adopted for controlling, the valve is opened at a constant speed at a certain speed, and after the valve gradually reaches the minimum controllable flow, the flow cascade control is carried out on the feeding valve. In this case, the small flow control range is 20% of the total feed (FJF 1-20%), the single-hearth feed is controlled to 12t/h (FAF 1-12), the control flow chart is shown in fig. 5, which illustrates an FF1 valve as an example, and when there are a plurality of valves, the same control logic may be used for control.

After 20% of feeding is performed in the feeding control process, the feeding amount is increased at a certain rate by the cooperative control method until the feeding process reaches 100% of load, the feeding amount is gradually increased to 100%, and the increase prompt is given during the period, so that the operator is informed to adjust the negative pressure of the cracking furnace and the hearth in time, as shown in fig. 6.

After the feeding is finished, the feeding control command automatically executes the following operations: the flow control of the dilution steam is changed into proportional cascade control, so that the flow of the dilution steam and the flow of the single group of feeding materials are controlled according to the proportion, a cracking furnace COT deviation controller is put into use, low flow linkage is put into use, the injection amount of DMDS is reduced, and the temperature of the cracking furnace COT is increased to the required cracking depth, as shown in figure 7.

And in the process of material returning control, material returning is started from 100%, in the process of 100% to 60%, the program returns the material at a certain material returning speed, after 60%, the DS proportional cascade control of the cracking furnace is changed into automatic flow control, and the set flow is 3.5 t/h. The DS flow is unchanged in the 60% to 40% material returning process, the dilution steam flow is increased to be controlled to be 5.5t/h in the 40% material returning to 20% process, and in order to prevent the over-temperature of the convection section, the purging steam flow is increased to be 5.5t/h by a single cracking furnace. And (4) after 20% of the feeding liquid is completely withdrawn, adopting valve opening control, and closing all the single group of feeding valves from the current opening to 0 opening at the same time. After the material returning is finished, the opening degree of a single group of feeding control valve is set to be 3 percent below zero, the opening degree of a total feeding electromagnetic valve is set to be 3 percent below zero, a feeding electromagnetic cut-off valve is closed, a DMDS injection valve is closed, an online sampling electromagnetic valve is closed, and an operator is prompted to switch the operation mode of the cracking furnace on a control panel.

Specifically, referring to fig. 8a-8d, the cooperative control method first collects the operating parameters of two cracking furnaces to be split, to determine whether the splitting condition is satisfied, the operating parameters include the pressure and temperature of the fuel gas system of the utility system, the liquid level of the separation tank, and the temperature and pressure of the dilution steam system; the states of important valves such as SS systems, fuel gas, feeding systems, dilution steam and the like of the two split cracking furnaces, and the information of the temperature, the negative pressure, the operation of a fan, the operation mode of the cracking furnaces and the like of a hearth. After the cooperative control program judges that the bisection condition is met, the feeding and returning materials are sent to the two cracking furnaces. Every time the feeding is carried out according to a certain proportion of the total feeding amount (within the range of 10-20 percent), the putting-in and putting-out time of the two cracking furnaces for completing the same feeding amount is kept consistent, the influence of the switching of the cracking furnaces on a subsequent system can be reduced, and the system fluctuation is reduced. And (3) acquiring total flow data of feeding of the two cracking furnaces in the whole process by the cooperative control program, pausing and waiting the cracking furnace with the higher feeding or returning speed when the total deviation exceeds a certain value (3-5t), continuing the paused cracking furnace after the feeding deviation of the two cracking furnaces is less than 2t, and continuing feeding and returning the two cracking furnaces to the program set value according to the original program. The system state of the cracking furnace is monitored in the whole process by the feeding control program and the returning control program, whether each index exceeds the standard is judged, if the operating parameter exceeds the range in the feeding and returning process, a pause instruction is sent to the material releasing or returning process of the cracking furnace, the cooperative control program receives the pause information of the cracking furnace fed back by the two cracking control programs in the whole process, the feeding or returning pause of any cracking furnace occurs, and the cooperative control program sends a pause instruction to the other cracking furnace. The logic is used for meeting the requirement of synchronous operation of the two cracking furnaces, and the fluctuation of feeding and returning materials is reduced. When the program detects that the total feeding flow of the material returning cracking furnace is 0t/h and the feeding amount of the material feeding cracking furnace is 46t/h (100% load), and the feeding sequence control program and the material returning sequence control program are completely fed back, the cracking furnace is prompted to complete the bisection.

The above scheme provided by the embodiment of the application comprises three parts: a feeding control program, a returning control program and a cooperative control program of the feeding and returning furnace. Before switching cracking furnaces, the scheme collects operation parameters of two opposite-cutting cracking furnace DCS systems through a cooperative control program, and judges whether the two cracking furnaces have opposite-cutting conditions currently or not by monitoring data such as a fuel gas system, a diluted steam generation system, a raw material system and a cracking furnace operation mode; the feeding control logic comprises the contents of controlling a feeding valve, controlling dilution steam and monitoring the abnormality of the cracking furnace which may appear in the feeding process of the cracking furnace from 0% to 100%, and the material returning control logic comprises the contents of controlling the valve, controlling the dilution steam and monitoring the abnormality of the cracking furnace which may appear in the material returning process from 100% to 0%. The cooperative control program is used for controlling the respective process control of the two cracking furnaces in the feeding and returning process, so that the total feeding amount is kept stable, and the influence on the downstream is reduced; the cooperative control program can also deal with the problem that the process is interrupted in time when the cracking furnace is abnormal during the feeding and returning period, and the cracking furnace is back to the safe state; the feeding and returning programs respectively comprise modifiable feeding process control parameters for controlling the feeding and returning speed.

The setting of the parameters and the threshold values in the above embodiments of the application may be adaptively selected according to an actual application scenario, or may be directly stored in the system after obtaining appropriate values in a calibration test manner in advance.

Some embodiments of the present application further provide a storage medium, where the storage medium stores program instructions, and after reading the program instructions, a computer executes the automatic feeding, returning and beveling control method for a cracking furnace according to any one of the above technical solutions.

Fig. 9 is a schematic diagram of a hardware structure of an automatic feeding and returning material bisecting control system of a cracking furnace provided in this embodiment, where the apparatus includes:

one or more processors 901 and a memory 902, where one processor 901 is taken as an example in fig. 9. The automatic feeding and returning material bisection control system of the cracking furnace can further comprise: an input device 903 and an output device 904. The processor 901, the memory 902, the input device 903 and the output device 904 may be connected by a bus or other means, and fig. 9 illustrates the connection by a bus as an example.

Memory 902, which is a non-volatile computer-readable storage medium, may be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. The processor 901 executes various functional applications and data processing of the server by running the nonvolatile software program, instructions and modules stored in the memory 902, that is, the automatic feeding and returning material-halving control method of the cracking furnace of the above method embodiment is realized.

The product can execute the method provided by the embodiment of the application, and has the corresponding functional modules and beneficial effects of the execution method. For technical details that are not described in detail in this embodiment, reference may be made to the methods provided in the embodiments of the present application.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some 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.