Project report plantwide process control
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This document summarizes a project to develop a control strategy for a Fluid Catalytic Cracking Unit (FCCU) to control various output parameters while handling complex dynamics. It examines different multivariable control methods and control loop pairings in a simulation. The best results were obtained using PI controllers for disturbances to the FCCU, which converts gas oils into valuable fuel gas and other products. Tables 1 and 2 describe the process and disturbance models used in the simulation, including interactions between manipulated and process variables and the effects of three disturbances on the process variables.
Project report plantwide process control
- 1. Kaustubh.A.Deshpande, Prathmesh.R.Kumbhare- Team M Missouri University of Science and Technology
- 2. 2 1. ABSTRACT The project incorporates the design of a control strategy for controlling various process output parameters of a Fluid Catalytic Cracking Unit (FCCU) which includes the complex dynamic responses in a refinery. To satisfy all the objectives, we examined different methods of multivariable control and control loop pairings using VisSim simulation tool and obtained the best results when using PI controllers for all the 3 disturbances. 2. INTRODUCTION The FCC Unit converts the gas oils into a range of hydrocarbon products of which, Y3, the fuel gas is the most valuable one. The objective is to obtain the necessary amount of fuel gas while keeping other streams within limits. Figures 1 and 2 represent the layout of the system to be controlled. Table 1 below gives the process models of the interactions between 6 Manipulated Variables (U1-U6) and 7 Process Variables (Y1-Y7). The table also shows the various Distributed Control Systems (DCS) for each Manipulated variable (U1-U6). There exists an exception for the process variable ‘Y5’ and ‘Y6’. The ‘U5’ input for these 2 processes does not
- 3. 3 pass through the DCS block and is directly applied to the individual processes. The gains of the process variables ‘Y4’ and ‘Y5’ were multiplied by 1.15 for simulation purposes. Table 1. FCC Unit Process Models Table 2 gives details about the effect of disturbances on the process variables Y1-Y7 when the disturbances are introduced to the system. D1- Change in feedstock composition D2- Change in feed preheat temperature D3- Change in ambient temperature
- 4. 4 Table 2. Disturbance Models For the purposes of simulation, all the operating points are considered to be zero and as a result the constraints are also changed. All the
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