Control Loops And Strategy Design Of Acetic Acid Reactor And Simulation

As an important class of basic organic chemical raw material, the development of acetic acid is a mirror of the organic chemical industry. The methanol carbonylation in acetic acid production is the most competitive in the market. With its overwhelming economic advantages, it occupies the dominant position. In the process, methanol reacts with carbon monoxide by catalyst, which ranks as a highly exothermic reaction. The heat released by the reaction causes temperature rising, then the increase of temperature accelerates the reaction rate. The process constitutes a positive feedback system, which makes the whole production process uncontrollable.The control strategy of reactor temperature control system is designed in this paper, by analyzing the reactor system and process parameters, combining with project design experience and design specification. In this strategy, the coarse control loops of system are methanol feed ration control loop and methanol cascade-feed forward temperature control loop. The former loop is for material flowing into flash tank, which is the primary means of reactor cooling; the later loop is for further stabilizing the reaction temperature. For the reaction is highly exothermic, these two control loops are not enough to remove all of the reaction heat, thus increases another control loop—cascade-split control loop.The excellent controller is important guarantee for controlling process parameters to reach the process operation requirements. Predictive functional control (PFC) is the third generation of model predictive control algorithm, which has advantages of controlling input regularity, less calculating time and high feasibility. In this paper, PFC controller for methanol temperature cascade-feedforward control loop is proposed, then simulate by MATLAB. The simulation result shows that PFC controller has capability of good tracking performance and anti-jamming.Measuring unit, such as temperature and flow meters, executive units, like control valves, are important parts of control loop. In this paper, the measuring key parameter, methanol flow meter and specially applied control valve are delicately designed, which are referred in the former control loops, satisfy the requirements in applications and achieve the target of control loops.