2015年自动化学院东南大学过程控制作业七.docx

The Seventh Exercise of Process Control Members:Students’ Tail Number 24/5/2015P410.4A three input–three output process has the following RGA:Λ = How would you pair variables for your control loops? Why?Solution:First of all, we know that we do not want to pair on a negative relative gain;Secondly, we do not want to pair with a relative gain of 0, because that means the particular input does not have an effect on the particular output, when all the other loops are open;Thirdly, try to pair on relative gains close to 1;According to the rules, we can pair the variables as follows: That is:P412.10The objective of a wet grinding circuit is to grind large solid material to form granular material. Solids are fed with a water stream to a ball mill where the solids are ground. The slurry effluent from the ball mill is fed to a sump which is used as surge capacity. The slurry is pumped to a cyclone separator, which separates water from solid material and returns water to the ball mill. A schematic diagram is shown below.Consider the following process model (mk:@MSITStore:E:\001大三\00Process%20control\Process%20control\Process.chm::/0133536408_ch13lev1sec11.htmlHulbert and Woodburn, 1983)Which has the following RGAa. What pairing is suggested by the RGA forth is system? Why? b. Connect the appropriate input and output variables with controller, on the diagram above, to form a control instrumentation diagram. c. Discuss the failure sensitivity of this three input-three output system. That is, if any of the control loops failed, would the resulting two input-two output system have the correct pairing?Solution:From row 2 and row 3, we know that only and are positive. In this case, we can only pair input and output as follows: That is:From the diagram; we know that we need a flow controller, a composition controller and a torque controller. In consideration of question a, we design the instrumentation diagram in figue 1:i. If the - control loop failed,So, Use matlab to get RG