案例7：加氢脱硫（HDS），混合进料和缓冲罐控制-1

案例7：加氢脱硫（HDS），混合进料和缓冲罐控制
(\ProgramFiles\ShellGlobalSolutions\PCTP\Tutorial\SMOCPro\Tutorial7_HDSandFeedandTank.wsp)
本研究案例是基于案例4的，并在流程的末尾额外增加了一只产品缓冲罐。这里的目的是为了阐明MIMO块的模型构建功能和子控制器行为的配置。
过程模型
建议过程按照以下配置：

Figure 1 - HDS with pre-blender and product buffer tank. 图1：带预混合器和产品缓冲罐的HDS.

与前面所研究的情况一样，柴油的Sulphur, T95和Density都从HDS（加氢脱硫反应器）的下游进行测定。本例中的过程控制问题是在保持产品缓冲罐液位在设定范围内的前提下，将这些指标控制在用户指定的限制以下。可用的MVs是Kero，LGO和HGO的进料混合比，所有的进料流量，炉出口温度，以及产品采出流量。
还存在空间将进料最大化设置为经济函数并为其设定最优化准则。CGO对比例控制的影响被显式建模并用作前馈干扰。我们的控制目标是使用此策略搭建并调谐一个SMOCPro控制器。
模型搭建
搅拌器和反应器的模型与案例4一样，如下图所示它们都使用MIMO块搭建：

双击MIMO块以打开搅拌器和反应器模型的详细参数视图。

MIMO块作为一个用于表达复杂传输功能的可管理替代品，取代了原来使用连接线（图）。它有助于组织块密集连接的对话框。请参考SMOCPro Help获取详细说明。
控制器设计
搅拌器与反应器的子控制器设计与案例4一样。本例的不同处在于增加了Tank_Level子控制器去控制缓冲罐液位。

Level是需要指定范围的CV。制定的Level_SP是与Level重复的，用于指定液位设定点的CV。

HDS Reactor的压缩点是默认的。然而，Tank_Level子控制器的压缩点被修改为：

最后，定义一个经济函数以最大化Feed。

系数-1.0认定SMOCPro执行经济函数最小化。
仿真
仿真的目的是为了演示斜坡性能和子控制器行为。

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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.

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2016.6.11