Control system and method for improving acrylonitrile production stability

Abstract

The invention provides a control system for improving acrylonitrile production stability. The system includes a recovery tower sensitive plate temperature controller, a recovery tower, a reboiler flow control loop, and a recovery tower feed flow control loop. The output ends of the reboiler flow control loop and the recovery tower flow control loop are connected to the input end of the recovery tower. The sensitive plate temperature controller and the reboiler flow control loop form a cascade closed loop. A temperature set value of the sensitive plate temperature controller and a measured temperature value of the recovery tower are output to a reboiler flow controller. The assemblies and the loops are controlled by automatic valves. The recovery tower flow control circuit is provided with a flow controller. The sensitive plate temperature controller and reboiler flow cascade closed loop is equipped with a calculation module. The feed amount of the recovery tower is input as a feedforward into the calculation module together with an output value of the sensitive plate temperature controller, thus forming a feedforward cascade control system. The control method is a method for realizing improvement of product acrylonitrile stability. The system and the method can improve the stability of acrylonitrile production.

Description

technical field [0001] The invention relates to a control system and method for acrylonitrile production, in particular to a control system and method for the temperature of an acrylonitrile production recovery tower. Background technique [0002] Most domestic acrylonitrile production units adopt the process of propylene ammoxidation to synthesize acrylonitrile, which has the advantages of short process flow, low investment, low cost, abundant source of raw materials and low price, high conversion rate of propylene and high yield of acrylonitrile, and the by-products of the process Recyclable, reducing industrial pollution. The process of propylene ammoxidation to synthesize acrylonitrile is very mature and economical in terms of catalyst, reactor, process flow, energy saving, and waste treatment. [0003] The recovery tower (also known as extractive distillation tower) in the acrylonitrile plant is an important equipment for improving product yield and controlling product...

AI Technical Summary

Problems solved by technology

[0007] The existing control system cannot detect the changes in the feed volume of the recovery tower or the fouling of the reboiler or the operating conditions of the absorption tower in time, and the response lags behind, which makes the temperature of the sensitive plate fluctuate greatly, seriously affecting the stable operation of the recovery tower , which has also become a difficult point in the stable control and stable production of the recovery tower

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