On-line soft measurement method of pH value and H2 SO3 concentration in acrylonitrile polymerization system

Abstract

The present invention relates to an on-line soft measurement method of pH value and H2SO3 concentration in polyacrylonitrile polymerization system under the sodium-chlorate-sodium bisulfite initiating system. It is characterized by that it utilizes the simulation experiment of NaClO3-NaHSO3 oxidation-reduction initiating system under the condition of operation in the course of acrylonitrile polymerization to make the obtained experiment result undergo the processes of mathematical regression and normalization treatment to obtain an integrated quantitative mathmatical expression formula of 5 operation variable quantities and pH value and H2SO3 concentration in said polymerization system: in which (ci, i=1,2,...4) and D (di, i=1,2,...4) are moded fitting parameter vector, lambda (lambda i, i=1,2,...4) and gamma (gamma i i=1,2,...4) are model fitting parameter matrix x is input vector, i.e. operation variable quantity, after calculation, the real time result of pH value and H2SO3 concentration in the acrylonitrile polymerization system can be obtained.

Description

technical field [0001] The present invention relates to online soft measurement technology, specifically a kind of sodium chlorate-sodium bisulfite initiation system in acrylonitrile polymerization system pH value and H 2 SO 3 Online soft measurement method for concentration. Background technique [0002] Polyacrylonitrile is the basic raw material for acrylic fiber production. The polyacrylonitrile aqueous phase two-step wet process has been put into production for many years in some factories in my country. The key stage in its production process that determines the quality of acrylic fiber products is the polymerization reaction. The process adopts aqueous phase precipitation polymerization, which carries out ternary copolymerization reaction of acrylonitrile (AN), methyl acrylate (MA) and sodium methacrylic sulfonate (A1). The copolymerization reaction has gone through a multi-step reaction process such as chain initiation, chain growth, chain termination and chain t...

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Problems solved by technology

[0007] However, due to various reasons, the current process equipment generally has no detection means for the above two important process parameters, so it is also impossible to have a deep and real-time understanding of the polymerization process, so that in actual production, often occur due to various Slight perturbations in feed amount and ingredient ratio lead to changes in polymerization parameters, making the quality of subsequent spinning unstable, but for no reason

[0008] The pH value of the polymerization system is mainly related to many factors such as system composition, reaction temperature, and water quality of the dispersed phase, and no comprehensive correlation equation related to each operating condition has been found so far.

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