Upload
vanliem
View
242
Download
0
Embed Size (px)
Citation preview
23.10.2012 1
Toolbox
Level 2 thermodynamicsMaria Zevenhoven
23.10.2012 2/37
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
23.10.2012 3/37
Toolbox
Level 2: ThermodynamicsSimple phase diagrams
23.10.2012 4/37
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
23.10.2012 5/37
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
23.10.2012 6/37
click “Phase Diagram”Answer “no”
23.10.2012 7/37
Press ”file”; ”directory”; ”change my files directry” and change it to your own USB stick
23.10.2012 8/37
Fill in “KCl”, Click on “+”,Fill in K2CO3,
23.10.2012 9/37
You can change units by clicking on “units” to mass
Check the format of the other units.Click “ok”
23.10.2012 10/37
Check databases that are included by clicking on “datasearch” select FT pulp and click “OK”, Click “next”
23.10.2012 11/37
Click “pure solids”, “FACT-MeltA” in solution speciesClick on the “variable bar” a new window will open
23.10.2012 Åbo Akademi University -Inorganic Chemistry FPK2-2008/MZ 12/37
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.
23.10.2012 13/37
Click “calculate”
23.10.2012 14/37
23.10.2012 15/37
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
23.10.2012 16/37
Equilibrium
Melting behaviour of BL ashes
23.10.2012 17/37
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
23.10.2012 18/37
23.10.2012 19/37
click “Equilib”Answer “no”
Carry over
23.10.2012 20/37
Add amounts and species that you calculated (Na2CO3, Na2SO4, KCl etc) check your units!!Choose again the right database FtpulpPress “next”
Carry over
23.10.2012 Åbo Akademi University -Inorganic Chemistry FPK2-2008/MZ 21/37
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”
23.10.2012 22/37
Carry over
Check the outputYou can plot these data or export them to xls.Choose “output”; “plot”, plot results”
23.10.2012 23/37
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”
23.10.2012 24/37
Click ”ok”
23.10.2012 25/37
Press ”plot”Ypu obtain now the melting curve and can determine the amount of melt from the curve
23.10.2012 26/37
Method 2
23.10.2012 27/37
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
23.10.2012 28/37
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