On-line soft measurement method of pH value and H2 S03 concentration in acrylonitrile polymerization system

A technology of H2SO3 and acrylonitrile, which is applied to the analysis of materials and instruments, and can solve problems such as changes in polymerization parameters, inability to understand the polymerization process, and unstable spinning quality in subsequent processes.

Inactive Publication Date: 2004-09-15
JIANGNAN UNIV +1
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  • Abstract
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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.

Method used

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  • On-line soft measurement method of pH value and H2 S03 concentration in acrylonitrile polymerization system
  • On-line soft measurement method of pH value and H2 S03 concentration in acrylonitrile polymerization system
  • On-line soft measurement method of pH value and H2 S03 concentration in acrylonitrile polymerization system

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Embodiment Construction

[0044] 1. Detect data, use conventional detection devices to detect operating variables, the specific operating variables are methyl acrylate (MA), acrylonitrile (AN), recovered monomer (RM), oxidant sodium chlorate (A2), reducing agent coke Eight kinds of material flows into the polymerization kettle, such as sodium bisulfite (A3), sodium methacrylic acid sulfonate (A1), beta hydroxyethane mercaptan (A4) and pure water (DW), and the reaction temperature of the polymerization kettle (A5 );

[0045] 2. Data preprocessing, convert the detected operating variables into percent concentration, and do normalization. The operating variables detected above can be sent to the computer, and the following variables can be converted by the computer:

[0046] ① Calculate the total flow;

[0047] ② Calculate the percentage concentration of sodium methacrylate sulfonate (A1) in the polymerization kettle;

[0048] ③ Calculate the percentage concentration of oxidant sodium chlorate (A2) in ...

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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 invention relates to on-line soft measurement technology, in particular to a pH value and H value in an acrylonitrile polymerization system under a sodium chlorate-sodium bisulfite initiation system 2 SO 3 On-Line Soft Sensing Methods for Concentration. Background technique [0002] Polyacrylonitrile is the basic raw material for acrylic fiber production. Polyacrylonitrile aqueous two-step wet process has been put into operation in some factories in my country for many years. The key stage in its production process that determines the quality of acrylic fiber products is the polymerization reaction. The process adopts aqueous precipitation polymerization, which terpolymerizes acrylonitrile (AN) with methyl acrylate (MA) and sodium methacrylate (A1). The copolymerization reaction goes through a multi-step reaction process including chain initiation, chain growth, chain termination and chain transfer. In this way, each small acrylonitrile molecu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N35/00
Inventor 杨慧中张素贞陶振麟黄翔宇顾文兰张超峰
Owner JIANGNAN UNIV
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