Lession 1 : Antoine Equation

Let's solve a simple problem.

(1-1)

We will use the Antoine equation which relates the vapour pressure of a pure substance to temperature. The equation is:

A, B and C are constants. The vapour pressure P can be calculated for a given temperature T, or the reverse calculation can find T for a given P. The source text of EQUATRAN is as follows.

// Antoine equation t -> P A = 7.87863 B = 1473.110 C = 230.00 LOG10(P) = A-B/(t+C) t = 25

• A maximum of 8 characters is allowed for variable names and both numeric numbers and alphabets can be used. The first character must always be an English letter.
• The equals sign (=) is used in its true mathematical sense, i.e. to indicate equality between the left and right sides of an equation. It is not an assignment as in computer programming languages where the variable on the left side is given the value calculated on the right. The expression on the left can therefore be complex, more than just a single variable.
• Many mathematical functions are available, for example the LOG10 function used here.
• Comments can be added to the source text by preceding a line with //. These lines are ignored by the solver.

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(1-2)

We can reverse the direction of the calculation without any need to rearrange the equation. Replace the last line of code to specify P instead of T and run again. This time the value of T is calculated.

// Antoine equation P -> t A = 7.87863 B = 1473.110 C = 230.00 LOG10(P) = A-B/(t+C) P = 760

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You will understand that calculation of the opposite direction is able to carry out without changing equations.

Sample problem

The following sample problems will help you understand how EQUATRAN-G works.

Lesson 1 : Antoine Equation
Lesson 2 : Heat Balance of Heat Exchanger
Lesson 3 : Boiling Point Calculation
Lesson 4 : Reaction Calculation
Lesson 5 : Simple Distillation

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