(300f) Computer Applications in Mineral Process Engineering - a Case Study in Mechanical Operations

ABSTRACT As part of the continuing work being carried out at the Center for CAD & CAI about one hundred °¥C' Programs are developed in the subject of Mineral Process Engineering and Mechanical Operations. These programs are readily useful for undergraduate teaching or for self study by the students.

The use of computers in the chemical engineering or Mineral Process Engineering education and teaching can be classified in to the following aspects:

Illustration of concepts: Subject concepts and mathematical techniques

Modeling and Simulation: Steady state and unsteady models and their solution on computer

Use of Packages: ASPEN, FLOWTRAN etc

There are several packages available for the purpose of flow sheeting and process design. Because of the black - box approach adopted in these packages, they are not readily useful to the discerning student except for obtaining final results or solution to the given problem. As such the details of the calculation procedure are not known. Even though these commercial packages, developed by dedicated teams of engineers, are sophisticated and are quite useful for process engineers working in a process design and consultancy organizations, their utility as teaching aids is limited. With a view to bridge the gap that is existing, Computer Aided Instructional Packages are being developed at the Center for Computer Aided Design and Computer Aided Instruction (CAD & CAI) in the Department of Chemical Engineering at Andhra University. The basic concept is to develop computer programs for instructional purpose as well as for self study by the students. Computer Aided Instruction, Computer Assisted Learning, Computer Applications and Computer Simulation all mean more or less the same; the application of computer for solution of problems. The solution of a problem on computer gives the student a thorough understanding simultaneously on three aspects namely the concept of a topic, the mathematical technique involved and the programming skill. This is true even with the straight forward problem which involves routine calculations. The real advantage of computer in solving the chemical engineering problems becomes obvious when the solution of the problem at hand involves repetitive calculations or when it needs the solution of any non-linear equations or any other mathematical technique is needed in the course of the solution. Many of the material and energy balance problems involve the use of matrix methods, solution of differential equations and numerical integration etc. At the CAD & CAI center, for the last few years computer programs in various chemical engineering subjects are being developed. In the project the following subjects are being covered. ?æ Stoichiometry (Material and Energy Balances) ?æ Fluid Flow ?æ Heat Transfer ?æ Mass Transfer ?æ Chemical Reaction Engineering ?æ Process Engineering Economics ?æ Mechanical Operations ?æ Process Control

In each of these subjects there are enough number of problems which can be adopted for computer calculations. The mathematical techniques covered include

?æ Solution of Non Linear Equations (Single and Sets) ?æ Solution of sets of Linear Equations ?æ Curve Fit and Interpolation ?æ Solution of ODE's, IVP and BVP ?æ Solution of Partial Differential Equations (Elliptic, Parabolic and Hyperbolic) ?æ Optimization - Linear Programming and Non - Linear Programming

In each of these courses, the subject concepts as well as the mathematical techniques are covered for selected problems. Further, by selecting similar examples from each subject for a given mathematical techniques good teaching material can be prepared. The papers on CAI so far presented in National and International Conferences are listed in Table - I. A few years ago the CACHE (Computer Aids for Chemical Engineering Education) Corporation, U.S.A., compiled about one hundred programs written in FORTRAN and published them in several volumes covering Stoichiometry, Kinetics, Process Control, Transport Properties, Thermodynamics and Equilibrium stage Computations.

In the same and similar way around twenty programs in "C" language are developed covering in the areas of filtration - Selection and design of rotary vacuum filter, design (dimensions of filter press), total area of filtrate surface area, optimum cycle time, total cycle time, cake thickness, minimum number of frames and thickness of frames, filtration constants, speed of rotation of filtrate equipment and washing time along with the application of numerical methods given below as per the requirement .

However, these programs are not amenable to the students at the undergraduate level. Many of the text books in their latest editions contain computer methods and calculations. For example, the fifth edition of Chemical Engineering Thermodynamics by Smith et al contains MATHCAD (R) and MAPLE (R) routines. The text book on Phase Equilibrium Thermodynamics by Walas contains BASIC programs. Balzhisher, in his book on thermo dynamics incorporated computer programs for problems which require repetitive calculations. The latest edition of Chemical Engineering Kinetics by Smith contains Numerical Methods for the solution of single and sets of ordinary differential equations in the reactor design. Similarly latest edition of Process Systems Analysis and Control by Coughanour contains BASIC programs. The latest publisher of Mechanical Operations for Chemical Engineers by Narayanan and Bhattacharya also contains some Computer Programs in FORTRAN and the fifth edition of Mineral Processing Engineering by B. A. Wills also contains some BASIC programs. Most of the recent books are also accompanied by software in the form of CD's. In view of the above, the importance of Computer Aided Instruction cannot be overemphasized.