engineeringreport@wiki

 

This chapter will briefly describe the background of the study which contained the description of the batch polymerization reactor, PID controller, polyethylene polymer and Aspen Plus programmer. The problem statement will discuss about why this research is done. It is also include the objective and scope of this research which will be what do I want to achieve in this research and the simulation is run under the certain scope.

1.1 Background of Study

I'm not sure why you need to describe these 3 things - how is it related to your topic? Perhaps it is better if you explain this here first before defining each in separate subsections

  

A batch polymerization reactor is jacketed, has a stirred tank. The reactor is rated for certain temperatures and pressure range which is 0-200oC and the pressure is 80 psig of full vacuum for 30 gallons tank. This reactor is widely used in the industry because of its operational flexibility which can be attractive and challenging in solving the industry’s control problems due to its nonlinearity, complexity, variability and uncertainty of the reactor.

 

 

PID controller is a proportional-integral-derivative controller which is a genericcontrol loopfeedback mechanismhad widely been used in the industrycontrol systems. The PID controller attempts to correct the error between a measuredprocess variableand a desiredset pointby calculating and then outputting a corrective action that can adjust the process accordingly.

 

From the algorithm calculations of the PID controller, it involves three separate parameters which are; the Proportional, the Integral and Derivative values. The Proportional value determines the reaction to the current error, the Integral determines the reaction based on the sum of recent errors and the Derivative determines the reaction to the rate at which the error has been changing. The weighted sum of these three actions is outputted to a control element such as the position of a control valve or power into a heating element.

 

By "tuning" the three constants in the PID controller algorithm the PID can provide control action designed for specific process requirements. The response of the controller can be described in terms of the responsiveness of the controller to an error, the degree to which the controller overshoots the set point and the degree of system oscillation.

 

Ultra high molecular weightpolyethylene(UHMWPE), also known as high modulus polyethylene (HMPE) or high performance polyethylene (HPPE) is athermoplastic. It has extremely long chains, withmolecular weightnumbering in the millions, usually between 2 and 6 million. The longer chain serves to transfer load more effectively to the polymer backbone by strengthening intermolecular interactions. These results in a very tough material, with the highestimpact strengthof any thermoplastic presently made.

 

It is highly resistant to corrosive chemicals, with exception of oxidizing acids. It has extremely low moisture absorption, very lowcoefficient of friction, is self lubricating and is highly resistant toabrasion(15 times more resistant to abrasion thancarbon steel). Its coefficient of friction is significantly lower than that ofnylonandacetal, and is comparable toTeflon, but UHMWPE has better abrasion resistance than Teflon. It is odorless, tasteless, and nontoxic.

1.1.4       AspenPlus Program

Thus - do you need this? This is not included in other descriptions. 

the ASPEN PLUSprogram allows to create our own simulation process model, starting with the flow sheet, then specifying the chemical components and operating conditions. ASPEN PLUS will take all of the specifications and we can simply simulate the model. The process simulation is the action that executes all necessary calculations needed to solve the outcome of the system, hence predicting its behavior. When the calculations are complete, ASPEN PLUS lists the results, stream by stream and unit by unit and we can observe what happened to the chemical species of the process model.

 

The chemical process industries are faced with an increasingly competitive environment, ever-changing market conditions, and government regulations. Yet, they still must increase productivity and profitability. Bottom line performance can be adversely affected by a many factors, such as production economies and product quality. Many of these factors are extremely complex and subject to varying degrees of unpredictability.

 

Process engineers routinely address these difficult issues. They are faced with challenges that range from the designing new processes to evaluating and improving performance of existing plants while they address these business objectives. By experiencing alone is not always the sufficient to answer the questions that continually arise. Efforts which are needed to provide meaningful insight is costly and potentially dangerous. To avoid production delays, downtime or off-spec product, process manufacturers require cost-effective tools that help identify and correct anticipated problems before they occur.

 

Previously there were researches done by few people to investigate the effect of temperature by using batch polymer reactor. But in those cases they used PID-fuzzy controller which is the most suitable with the dynamics change with the operating point and there might be other essentials nonlinearities in the process (Ljung, 1996). The variety application of this controller indicates that this technique has becoming the important tool for complex process (Lee, 1990). They found that this is the promising way to deal with industrial control problems.

 

Thus, this research is done to investigate the effect on the polymer’s gain concentration by using the same controller which is the PID controller. This simulation will be design by using Aspen Plus program. By the end of the simulation we will manage to determine weather the PID controller is also the most suitable controller to achieve the optimum value of the gain concentration.

 

Designing batch polymerization reactor by using Aspen Plus to obtain an      

optimum value of the gain concentration.

This simulation process will be done under these scopes of experimental, which are:

     1. This polymerization process will be done by using by only bract reactor.

     2. To obtain the optimum gain concentration the simulation will be controlled 

         by PID controller. 

     3. This simulation process will only use the polymer.

     4. The simulation process will be designed by using Aspen Plus.