在这种情况下，我们模拟一个影响底部质量的斜坡干扰。这一干扰会导致底部质量瞬间超过上限。如果该计算打开，底部质量CV违反上限后，我们预计有以下行动：
•计算3将顶部质量CV的priority（优先级）设定为10；
•计算5将reflux（回流）的max move size（最大动作幅度）设定为150；
•计算6将再沸器负荷的max move size（最大动作幅度）设定为1.5；
当底部质量CV值在范围之内时，我们预计：
•计算3将把顶部质量CV的priority（优先级）恢复到1；
•计算5将reflux（回流）的max move size（最大动作幅度）恢复到100；
•计算6将再沸器负荷的max move size（最大动作幅度）恢复到1.5。
若要查看计算结果，当控制器拒绝了仿真底部质量干扰时，我们将内核调试文件打开并保持25步。
逐步运行仿真直到第15步。如下面屏幕截图所示，在这一点，我们可以通过单击“bug”按钮打开调试文件：
•我们注意到的第一点是，尽管底部质量在范围内，EF tracking filter（EF跟踪滤波）值依旧改为300秒。注意在原始方案中我们将EF tracking filter设定为0.0。通过确认EF tracking filter至少是5mins，计算7确认该过程不受到过于激烈的动作。
•对于内核后计算，我们注意到底部质量CV的稳态约束行为表示了值101。值101意味着由于经济函数原因（即经济优化将一个变量推向约束），在稳态时约束是活动的。
当底部质量违反了上限，计算将分别把回流的最大动作和再沸器负荷设置为150和1.5。
当底部质量违反了上限时，顶部质量CV的优先级将降为10。
一旦控制器拒绝了干扰，并将底部质量带回限制内，计算将把变量恢复回标称值。
仿真2
我们将观察的下一个仿真称为“Disconnected POVs”。其仿真参数如下所示。
在第6步，我们预计计算1将移去底部质量CV。在第8步，我们预计由于计算2的原因，顶部质量CV将被移去。随后由于计算4，子控制器将切换到非活动状态。鉴于控制器只有一个子控制器，我们预计在第8步控制器将变成standby（待机）状态。
原文：
In this case, we simulate a ramp disturbance that affects the bottom quality. This disturbance causes the bottom quality to exceed its upper limit in the transient. If the calculations are turned ON, we expect the following when the bottom quality CV violates its upper limit
• Calculation 3 sets the priority for the top quality CV to 10
• Calculation 5 sets the max move size for reflux to 150
• Calculation 6 sets the max move size for reboiler load to 1.5
When the bottom quality CV is within limits, we expect
• Calculation 3 reverts the priority for the top quality CV back to 1
• Calculation 5 reverts the max move size for reflux back to 100
• Calculation 6 reverts the max move size for reboiler load back to 1.5
To view the results for the calculations, we turn the kernel debug file ON for 25 steps while the controller rejects the simulated bottom quality disturbance.
Run the simulation stepwise until the 15th step. At this point, we may open the debug file by clicking on the “bug” button as shown in the screenshot below
•The first aspect we notice is that even though the bottom quality is within limits, the EF tracking filter value has changed to 300 seconds. Notice in the original scenario that we left the EF tracking filter at 0.0. By ensuring that the EF tracking filter is at least 5 minutes, calculation 7 ensures that the process is not subject to overly aggressive moves.
• For the post-kernel calculations, we notice that the steady-state constraint activity for the bottom quality CV indicates a value of 101. A value of 101 implies that the constraint is active at steady state due to economics (i.e. due to the economic optimization pushing the variable against a constraint).
When the bottom quality violates its upper limit, the calculations set the max moves for the reflux and reboiler load to 150 and 1.5 respectively.
The priority for the top quality CV is lowered to 10 when the bottom quality violates its upper limit.
Once the controller rejects the disturbance and brings the bottom quality within limits, the calculations revert the variables back to their nominal values.
**Simulation 2 **
The next simulation that we observe is called “Disconnected POVs.” The simulation parameters are shown below.
At step 6, we expect calculation 1 to remove the bottom quality CV. At step 8, we expect the top quality CV to be removed as a consequence of calculation 2. Subsequently, the sub-controller is turned inactive due to calculation 4. Since the controller has just the one sub-controller, we expect the controller to shed to standby at step 8.
2016.6.16
网友评论