案例7：加氫脫硫（HDS），混合進料和緩沖罐控制
(\ProgramFiles\ShellGlobalSolutions\PCTP\Tutorial\SMOCPro\Tutorial7_HDSandFeedandTank.wsp)
本研究案例是基于案例4的，并在流程的末尾額外增加了一只產(chǎn)品緩沖罐。這里的目的是為了闡明MIMO塊的模型構(gòu)建功能和子控制器行為的配置。
過程模型
建議過程按照以下配置：
與前面所研究的情況一樣，柴油的Sulphur, T95和Density都從HDS（加氫脫硫反應(yīng)器）的下游進行測定。本例中的過程控制問題是在保持產(chǎn)品緩沖罐液位在設(shè)定范圍內(nèi)的前提下，將這些指標控制在用戶指定的限制以下?？捎玫腗Vs是Kero，LGO和HGO的進料混合比，所有的進料流量，爐出口溫度，以及產(chǎn)品采出流量。
還存在空間將進料最大化設(shè)置為經(jīng)濟函數(shù)并為其設(shè)定最優(yōu)化準則。CGO對比例控制的影響被顯式建模并用作前饋干擾。我們的控制目標是使用此策略搭建并調(diào)諧一個SMOCPro控制器。
模型搭建
攪拌器和反應(yīng)器的模型與案例4一樣，如下圖所示它們都使用MIMO塊搭建：
雙擊MIMO塊以打開攪拌器和反應(yīng)器模型的詳細參數(shù)視圖。
MIMO塊作為一個用于表達復雜傳輸功能的可管理替代品，取代了原來使用連接線（圖）。它有助于組織塊密集連接的對話框。請參考SMOCPro Help獲取詳細說明。
控制器設(shè)計
攪拌器與反應(yīng)器的子控制器設(shè)計與案例4一樣。本例的不同處在于增加了Tank_Level子控制器去控制緩沖罐液位。
Level是需要指定范圍的CV。制定的Level_SP是與Level重復的，用于指定液位設(shè)定點的CV。
HDS Reactor的壓縮點是默認的。然而，Tank_Level子控制器的壓縮點被修改為：
最后，定義一個經(jīng)濟函數(shù)以最大化Feed。
系數(shù)-1.0認定SMOCPro執(zhí)行經(jīng)濟函數(shù)最小化。
仿真
仿真的目的是為了演示斜坡性能和子控制器行為。
原文：
Case 7: Hydro-desulphurization (HDS), Feed Blending and Buffer Tank Control
This case study is based on Case 4 with an extra product buffer tank at the end the of process. The objective here is to demonstrate the model building capabilities with MIMO blocks and the sub-controller behavior configuration.
Process Model
Consider a process with the following configuration:
Just as in the previous case study, gasoil Sulphur, T95 and Density are measured downstream from the HDS reactor. The process control problem in this example is to control these qualities below user-specified limits while maintaining the buffer product tank level within the setrange. The available MVs are the Kero, LGO and HGO feed blending ratios, the overall Feed flow, the furnace outlet Temperature and lastly, the product outlet flow.
There also exists room to setup an optimization criterion with Feed maximization setup as the economic function. The influence of the CGO on the ratio control is explicitly modeled and used as a feed forward disturbance. The control goal is to build and tune a SMOCPro controller using this strategy.
Model Building
The blender and reactor model are the same as in Case 4, however they are built with MIMO blocks as shown below:
Double click on the MIMO blocks to open the detailed parameter view for the Blender and Reactor models.
The MIMO block is a manageable alternative to express complex transfer functions without using connection lines (drawings). It helps to organize the block dialog with dense connections. Please refer to SMOCPro Help for detailed instructions.
Controller Design
The blender and reactor sub-controller designs are the same as in Case 4. The difference in this example is the addition of the Tank_Level sub-controller to control buffer tank level.
Level is the CV used to specify setrange. The elaborated CV, Level_SP, is the duplication of Level that is used to specify the level setpoint.
The compaction points for the HDS Reactor are the default ones. However, the compaction points for the Tank_Level sub-controller are modified to be:
Lastly, define an economic function to maximize the Feed.
The factor -1.0 accounts for the fact that SMOCPro performs the minimization of the economic functions.
Simulation
The objective of the simulation is to demonstrate the ramp behavior and sub-controller behavior.
2016.6.11
