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Toolbox

Level 2 thermodynamicsMaria Zevenhoven

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First

Grade:You will be given a grade from 1-5 based on how you have managed this exercise:– 1: you have been here but you have no results– 2: you have got some results, but without any particular meaning– 3: you have got results that give some meaning– 4: you have found some results that are consistent with experience

and the literature– 5: you have found some interesting new data

Exam: Your grade in this exercise will be used as points in the exam for

this course (corresponding to one out of six questions in the exam). You have to participate in all exercises and carry over calculation

and get them approved to be allowed to do the exam

You will have to save your files on your own USB stick

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Toolbox

Level 2: ThermodynamicsSimple phase diagrams

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Calculating the melting behaviour of KCl-K2CO3 mixtures

With this exercise you will learn how to calculate a phase diagram in a simple 2 component system

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In a 2 component system you can determine T0 and T15 and T70 and T100 with help of the lever rule

Calculate a phase diagram P 1 atm T 300-1500K Determine these values for mixture containing

– 0.2% wt K2CO3 if possible

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click “Phase Diagram”Answer “no”

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Press ”file”; ”directory”; ”change my files directry” and change it to your own USB stick

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Fill in “KCl”, Click on “+”,Fill in K2CO3,

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You can change units by clicking on “units” to mass

Check the format of the other units.Click “ok”

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Check databases that are included by clicking on “datasearch” select FT pulp and click “OK”, Click “next”

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Click “pure solids”, “FACT-MeltA” in solution speciesClick on the “variable bar” a new window will open

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Check variables: “yx diagram”, composition “1” and click “nextChange the “constant” T to “Y axis”Fill in temperature rangeP can be kept constant Change the composition to KCl “0”, K2CO3 “1”, “X axis”, “1 max”, “0 min” Click “ok”

In a 3 component system you have to click “ABC” in variables, T will be kept constant.

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Click “calculate”

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Click in different areas to show what phase is stable

You can print phase diagrams, by moving the cursor you can see where T0, T15 etc are situated (coordinates are shown in the down left corner)

Determine and report T0, T100,

What is the amount of melt at T0? What does this mean from a deposit point of view?

Determine T70 and T15 if possible

Report the phase diagram

If you are done you can close the window

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Equilibrium

Melting behaviour of BL ashes

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Carry over Dr. K has burned BL in different

boilers Choose two cases (as different from

one and another as possible) Prof M. states that usually S is

depleted in “carry over particles Assume an EF (enrichment

factor)=0.7 for S in carry over ash Calculate the carry-over composition

when assumed that the ion balance has to be OK and the only ions are Na, K, SO4, CO3 and Cl(calculate the amount CO3 first)

Assume all Cl goes to K, S to K and then to Na, rest is Na2CO3

Calculate the composition as wt% (KCl, Na2SO4, K2SO4, Na2CO3)

Calculate the melting behaviour using Factsage (see below)

What is T0, T15, T70, 100 What are the differences in these 2

BL’s and carry over? Can you explain?

Black liquorDry

solids % Na g/kgds S g/kgds K g/kgdsCl

g/kgdsA 81,0 224,0 61,5 30,5 10,2B 79,4 205,0 64,5 25,5 2,0C 72,5 214,0 58,1 21,0 9,0D 76,5 169,8 67,9 25,2 2,6E 82,7 224,0 65,5 13,0 1,5G 77,9 206,5 70,5 23,0 1,2H 69,2 205,4 66,3 16,3 0,9I 82,2 189,5 62,1 21,7 3,3J 74,1 213,0 67,5 21,0 1,0

Remember:2[SO4

2-]+[Cl-]+2[CO32-]=[Na++K+]

Mw g/mol– Na 22.99– S 32.065– SO4 96.061– K 39.098– Cl 35.453– O 15.999– C 12.011– CO3 60.008

– KCl 74.551– K2SO4 174.257– Na2SO4 142.041– Na2CO3 105.988

1. Calculate amount of S in carry over (g/kg ds)

2. Calculate the amount ofNa, K, Cl, S on molar basis

3. Calculate amount of CO3

Now I know Na, K, SO4, Cl, CO3 (mol/kg ds)4. Calculate the amount of

KCl, then K2SO4, thenNa2SO4 and then Na2CO3formed (mol/kg ds)

5. Calculate back to g/kg6. Calculate %wt

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click “Equilib”Answer “no”

Carry over

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Add amounts and species that you calculated (Na2CO3, Na2SO4, KCl etc) check your units!!Choose again the right database FtpulpPress “next”

Carry over

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Check the right databases: “FTpulp-MELTA”, “FTpulp-Hexa”, ”FTpulp-ACL”

Carry over

Choose T(C) 400 1000 1 (Tmin= 400C, Tmax = 1000C you calculate with a ∆T=10)If you want to know exactly the T where a phase transition takes place you can click”transitions” in the lower right cornerPress ”calculate”

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Carry over

Check the outputYou can plot these data or export them to xls.Choose “output”; “plot”, plot results”

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Choose ”axes”; press ”y variables” and set the right valuesDo the same for ”x variables”; press nextChoose ”select” under species and look for Melt A; select by clicking before ”meltA”

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Click ”ok”

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Press ”plot”Ypu obtain now the melting curve and can determine the amount of melt from the curve

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Method 2

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Go back to the input windows.Right click before FT pulp meltand choose P

Remove T intervalPress ”calculate”

Now you calculatewhen the melt willturn gas=T100

Do the same butchoose F, put massin the precipitate

target to 0, 15 and 70Check that you have a relevant T there for initial value

Now you knowT0, T15, T70Check with method 1

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Report

Melting of a KCl-K2CO3 mixture (2p)– 2 component phase diagram– T0,T15,T70, T100

Carry over (3p)– Input calculation– Melting curves– Explanation

Total 5 points