Soft measuring method for on-line determining petroleum naphtha quality index on top of primary tower

Abstract

The invention discloses a soft instrumental technique to determine the index of the quality of the naphtha (dry points) on the top of a primary tower on line. The invention selects such variables as the handling capacity of the primary tower, the tower top temperature, the tower top pressure, the top reflux unit handling capacity temperature difference, the reflux ratio, the flow of the naphtha on the top of the primary tower, the unit handling capacity temperature difference of a first middle segment circulating reflux of the primary tower and so on as the input variables of the soft instruments of dry points of the naphtha on the top of the primary tower; making use of the values of relevant measuring instruments of the primary tower to directly measure or indirectly calculate the acquired values measured in real time; and acquiring the manual analysis values of the dry points of the naphtha on the top of the primary tower of the previous moment through the human-computer interface of the total distributed control system of a production plant; online computation based on the soft instrument model of the neural net established based on the sample data training of the industrial plant; weighing and correcting the calculated values of the model through analysis of the predicted deviations of the system to determine the dry points of the naphtha on the top of the primary tower on line and in real time. The online calculated values of the soft instruments of the dry points of the naphtha on the top of the primary tower can be used to give instructions in respect of operation, and used as the basis to control the values according to the quality index.

Description

technical field [0001] The invention belongs to the intersecting field of petroleum refining and process control, and relates to an online method for determining the quality (dry point) index of naphtha, an initial distillation tower top product in an atmospheric and vacuum production device of petroleum refining. Background technique [0002] Due to the increasingly serious world energy problems and the unpredictable changes in the crude oil market and refined oil market, the quality and price of crude oil have become important factors for the world's oil refining industry to choose refined crude oil. Atmospheric and vacuum equipment is the primary production link of the entire oil refining industry, among which the initial distillation tower, atmospheric tower and vacuum tower are the key equipment of the atmospheric and vacuum equipment, responsible for completing the main process of crude oil primary processing. Atmospheric and vacuum units directly process crude oil, cu...

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Problems solved by technology

[0007] (1) The composition of the oil processed by the petroleum fractionation tower is complex, often changes, and the properties of the oil are usually difficult to obtain in time. There are many operating variables, there are interactions, and the impact on product quality is complicated. It is difficult to establish an accurate mechanism model in time.

[0008](2) There are many operating variables that affect the quality of distillate oil and there are interactions. The input variables of the statistical model usually have a large number of redundant variables, which makes the stability of the established model poor ; or too simplistic, it is difficult to describe the change law of distillate quality indicators

[0009](3) Due to the frequent changes of refined crude oil and the properties of crude oil cannot be obtained in time, a large number of statistical model methods did not consider the changes in the properties of refined crude oil, resulting in a decrease in model accuracy, Even seriously deviated from the sampling analysis value

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