ForK Tutorial

ForK Tutorial Exercise 2 Creating new simulation projectto estimate explosion hazard

Aim: Determination of critical conditions of thermal explosion for a storage tank (drum) containing 80% solution of cumene hydroperoxide in cumene (well stirred assumption)

Drum:Cylinder with R=0.2 m, H=0.8 m, V=0.1

m3 (100 l),

S=1.26 m2 ; void volume VV=0.01 m3 (10 l), phi=1.01 (contribution of mass heat capacity of the container is small)

Product properties: =0.8 g/cm3. Cp=2 J/g/K, sample mass = 80 kg, initial

temperature – 20 oC, phi=1.01

Heat exchange:General mode, U=10 W/m2/K;

Tenv=50 oC

Aim: Determination of critical conditions of thermal explosion for a storage tank (drum) containing 80% solution of cumene hydroperoxide in cumene (well stirred assumption)

Drum:Cylinder with R=0.2 m, H=0.8 m, V=0.1

m3 (100 l),

S=1.26 m2 ; void volume VV=0.01 m3 (10 l), phi=1.01 (contribution of mass heat capacity of the container is small)

Product properties: =0.8 g/cm3. Cp=2 J/g/K, sample mass = 80 kg, initial

temperature – 20 oC, phi=1.01

Heat exchange:General mode, U=10 W/m2/K;

Tenv=50 oC

Click here to continueRun Scoring

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ForK Tutorial Exercise 2 Creating new simulation projectto estimate explosion hazard

Kinetics: Complex reaction with 2 stages in parallel:(1) A B – N-order initiation reaction; stage rate

– r1

(2) A+B 2B – autocatalytic stage; stage rate -

r2

Math model:(1):

lnK01=20.4; n11=2; E1=102 kJ/mol; Q1=800 J/g

(2)

lnK02=23; n21=4; n22=3; E2=96 kJ/mol; Q2=1800 J/g

Kinetics: Complex reaction with 2 stages in parallel:(1) A B – N-order initiation reaction; stage rate

– r1

(2) A+B 2B – autocatalytic stage; stage rate -

r2

Math model:(1):

lnK01=20.4; n11=2; E1=102 kJ/mol; Q1=800 J/g

(2)

lnK02=23; n21=4; n22=3; E2=96 kJ/mol; Q2=1800 J/g

Click here to continue

)RT

Eexp()1(kr 111n

011

)RT

Eexp()1(kr 222n21n

022

rQrQdt

dQ ;rr

dt

d221121

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Select Simulation mode

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Preliminary adjustment:

setting appropriate units

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Defining the drum model

Step 1. Defining general data

Data that are to be assigned:1. Response to be simulated

(heat production)2. Mass of a reagent and initial T3. Void volume and pad gas data (in our case Pgo and Tgo are optional)4. Mass specific heat and phi-factor

72

.01

1.01

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General data are ready

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Defining the drum model

Step 2. Defining Heat exchange mode

Data that are to be assigned:1. Heat exchange mode - General

2. Неat exchange Surface3. Неat transfer coefficient4. Environment temperature

(on the “Env. Temperqature” tab)

1.26

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50 60.1

60.0

59.9

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Defining the drum model

Step 3. Defining kinetic model

Data that should be assigned:

1. Model structure2. “Elementary” models for stages

3. Kinetic parameters

Creating model of two stages in parallel (the model of full autocatalysis)Stage 1 – of N-order typeStage 2 - Proto

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Data that should be assigned:

1. Model structure2. “Elementary” models for stages

3. Kinetic parameters

1. Creating model of two stages in parallel (the model of full autocatalysis)

Stage 1 – of N-order typeStage 2 - Proto

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Data that should be assigned:

1. Model structure2. “Elementary” models for stages

3. Kinetic parameters

1. Creating model of two stages in parallel (the model of full autocatalysis)

Stage 1 – of N-order typeStage 2 - Proto

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Data that should be assigned:

1. Model structure2. “Elementary” models for stages

3. Kinetic parameters

1. Creating model of two stages in parallel (the model of full autocatalysis)

Stage 1 – of N-order typeStage 2 - Proto

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Data that should be assigned:

1. Model structure2. “Elementary” models for stages

3. Kinetic parameters Model created with the

kinetic parameters for the second stage defined

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Data that should be assigned:

1. Model structure2. “Elementary” models for stages

3. Kinetic parameters Kinetic parameters for

the first stage have been defined

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Evaluating critical parameters of thermal explosion by using the “Effect of controls” option

1. Adjusting time interval for simulation

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Note that max temperature rise (overheat) at initial environment T=60 C is very small. Next step is to elevate env. temperature

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At Tenv=75 C overheat becomes much bigger. Continue to elevate Tenv till reaching explosion

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There is pronounced thermal explosion at Tenv~77.5 C. More precise value can be obtained by varying Tenv with smaller step

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Simulation of thermal explosion in the drum

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Add simulated responses to be saved within the project

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Now the complete project can be saved into a data volume for further use

The 2st Exercise is over.

Press [Esc] to close presentation.

If you have ForK installed we recommend to repeat this exercise by yourself.