Gas phase polyethylene device quality index and operational constraint on-line estimation system and method thereof

Abstract

The invention provides a polyethylene (PE) multi-trademark product quality index and operational constraint on-line estimation system for gas phase fluidized bed production technology. The system comprises a field process instrument which is connected with a gas phase PE object, a field analysis instrument, a distributed control system (DCS), a laboratory analysis data server and an advanced control server. The advanced control server includes an OPC client, a data interface module, a multi-trademark PE production process quality indicator and operational constraint model prediction module, a PE quality index prediction model parameter adaptive correction module, and a PE quality index robustness suboptimal filter estimation and quality indicator and operational constraint display module. The invention also provides a gas phase PE quality index and operational constraint on-line estimation method. The invention provides the real-time online estimation system and method of multi-trademark gas phase PE product quality index melt index and density, gas phase PE production operating constraint yield, and recycle gas dew point temperature.

Description

technical field [0001] The invention relates to the field of industrial process control, and is an online estimation system for the quality index and operation constraints of a polyethylene device for a gas-phase fluidized bed production process. Background technique [0002] Polyethylene (PE) is the most productive variety among polyolefins. As a thermoplastic polymer, it is widely used in various fields of the national economy such as industry, agriculture, national defense, and daily necessities. At present, polyethylene accounts for 70% of the world's total consumption of polyolefins, 44% of the total consumption of thermoplastic general-purpose resins, and the raw materials used account for 52% of the world's ethylene consumption. 70% of the output (Qian Bozhang. The technical progress of contemporary polyethylene production. International Chemical Information, 2002, 1: 9-11.). The polyethylene production process of the gas phase process includes five reversible reacti...

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Problems solved by technology

[0006] In order to overcome the limitations of the existing quality index and operating constraint estimation technology used in the gas phase PE process, which is difficult to adapt to frequent brand switching and widespread unknown interference, and thus difficult to run for a long period of time, the present invention provides a method for gas phase fluidized bed production. The online estimation system and method of polyethylene (PE) multi-brand product quality indicators and operational constraints, the key point of which is: combining the strengths of the mixed model modular design method and the semi-parametric design method, the quality of the gas phase PE process is constructed. The prediction model of the index and operation constraints; the self-adaptive adjustment of the quality index prediction model when the brand is switched is realized by using the module reverse push adaptive method; the robust suboptimal filtering considering the approximation deviation and process uncertainty of the quality index prediction model is used Estimation method, combined with laboratory analysis data, realizes real-time estimation of PE multi-brand product quality indicators and operational constraints

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