Lesson 4 : Reaction Calculation

Let's solve ordinary differential equations (ODEs).

(4-1)

We will calculate the concentration change with the next first order reaction, and assume that the initial concentration of A, B is 10 and 0.

/* Reaction */ A' = -k*A // first order reaction B' = k*A A#10; B#0 k=0.1 INTEGRAL t[0,30] STEP 0.1 // definition of integration TREND A, B STEP 1

• The INTEGRAL statement performs integration calculation. t is the integral variable, [0,30] is the integration period, and the STEP term is the integral step.
• The TREND statement outputs the integration process.

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(4-2)

About the next consecutive reaction, we will add a differential equation and solve three ODEs simultaneously.

/* Reaction */ A' = -k1*A // Consecutive reaction B' = k1*A-k2*B C' = k2*B A#10; B#0; C#0 k1=0.1; k2=0.08 INTEGRAL t[0,30] STEP 0.1 // definition of integration TREND A[0,10], B[0,10], C[0,10] STEP 1

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(4-3)

We will determine the reaction rate constants k1 and k2 from experimental data in the previous problem.

/* Reaction */ FUNCTION REACT(k1,k2,td;Ac,Bc) VAR td(3),Ac(3),Bc(3) A' = -k1*A // consecutive reaction B' = k1*A-k2*B C' = k2*B A#10; B#0; C#0 INTEGRAL t[0,30] STEP 0.1 // definition of integration Ac#0; Bc#0 CHANGE(Ac#A, Bc#B) ON (t>td) END VAR Ae(3),Be(3),Ac(3),Bc(3) VAR td(3)=(5, 15, 25) ,Ad(3)=(6.1, 2.2, 0.8) ,Bd(3)=(3.2, 3.9, 2.7) REACT(k1,k2,td,Ac,Bc) FIND (k1#1[0,2],k2#1[0,2]) LEAST (Ae,Be) Ae=Ac-Ad; Be=Bc-Bd OUTPUT k1,k2,Ae,Be

• The FIND statement is specified to calculate by least squares method.

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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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