Density and speed of sound in CO2 mixtures

21GRD06 Me CCUS
Pape on he measu emen o he he mophysical p ope ies o CO2
mix u es o CCUS (wi h a ge unce ain ies: o densi y be e han 0.1
%, o speci ic hea capaci y be e han 1 %, o iscosi y less han 3 %,
o speed o sound in liquid be e han 0.05 %, o gas phase a high
empe a u e 0.03 %) submi ed o an open access pee -
e iewed jou nal
D7 - A4.1.5
O ganisa ion name o he lead pa icipan o he deli e able:
Is i u o Nazionale di Rice ca Me ologica
and
S. Lago (INRiM), P. A Giuliano Albo (INRiM) and A. Qua one (INRiM),
A. Mo eau (UVa), X. Pe edes (UVa), F. Vélez (UVa),
Due da e o he deli e able:
01.04.2025
Ac ual submission da e o he deli e able:
23.10.2025
Con iden iali y S a us: PU - Public, ully open ( emembe o deposi public deli e ables in a us ed eposi o y)
Deli e able Co e Shee
Funded by he Eu opean Union. Views and opinions exp essed a e
howe e hose o he au ho (s) only and do no necessa ily e lec hose
o he Eu opean Union o EURAMET. Nei he he Eu opean Union no
he g an ing au ho i y can be held esponsible o hem.
The p ojec has ecei ed unding om he Eu opean Pa ne ship on
Me ology, co- inanced om he Eu opean Union’s Ho izon Eu ope
Resea ch and Inno a ion P og amme and by he Pa icipa ing S a es.
1 o 5
The modynamic p ope ies o ca bon dioxide and amine
1
bina y mix u es o CCUS
2
S. Lago
a
, A. Mo eau
b
, A. Qua one
a
, X. Pa edes
b
, F. Vélez
b
, P. A. Giuliano
3
Albo
a
4
a
Is i u o Nazionale di Rice ca Me ologica (INRiM), S ada delle Cacce 91, 10135 To ino,
5
I aly
6
b
Te moCal Resea ch G oup, Bioeconomy Resea ch Ins i u e BioEcoUVa, Uni e si y o
7
Valladolid, Paseo del Cauce 59, 47011 Valladolid, Spain.
8
Abs ac
9
Accu a e knowledge o he he mophysical p ope ies o CO
2
- ich sys ems is
10
c ucial o ensu ing he success ul deploymen o CCUS echnologies ac oss Eu-
11
ope. Unde s anding he he mophysical p ope ies o ca bon dioxide mix u es
12
wi h a ange o po en ial impu i ies e eals gaps be ween he expe imen al da a
13
equi ed o he sys ems design and ope a ion.
14
In his con ex , impo an expe imen al p ope ies we e measu ed o CO
2
+
15
monoe hanolamine and CO
2
+ die hanolamine bina y mix u es, suppo ing he
16
de elopmen o mo e ened and accu a e o mula ions o dedica ed equa ions
17
o s a e.
18
1. Ma e ials o CCUS
19
Monoe hanolamine (MEA) and die hanolamine (DEA) a e, among he mos
20
common alkanolamines, used in sou gas abso p ion echnology. Thei abil-
21
i y o chemically abso b ca bon dioxide ia exo he mic eac ions makes hem
22
i al componen s in ca bon cap u e, u iliza ion, and s o age (CCUS) echnolo-
23
gies. Fu he mo e, MEA and DEA se e as benchma ks in e alua ing new
24
CO
2
abso ben ma e ials. Thei es ablished pe o mance, combined wi h well-
25
documen ed limi a ions, make hem e e ence poin s o he modynamic mod-
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elling and op imiza ion o nex -gene a ion sol en s. Cu en esea ch in CCUS
27
aims o disco e o de elop al e na i e sol en s wi h imp o ed he mal s a-
28
bili y, educed egene a ion ene gy, and lowe co osi eness, while main aining
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compa able abso p ion capaci ies. In his con ex , a deepe he modynamic un-
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Email add ess:
s.lago@in im.i
(S. Lago)
P ep in submi ed o Else ie No embe 21, 2025
de s anding o hese subs ances con ibu es o he ongoing eo o op imize
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CCUS echnologies and ansi ion owa d mo e sus ainable indus ial p ac ices.
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2. Densi y measu emen s
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Fo densi y
ρ
measu emen s, a ib a ing ube densime e was used. The
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wo king p inciple is based on he elec omagne ic exci a ion o a U-shaped
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Has elloy ube which con ains a uid inside, whe e he undamen al oscilla-
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ion pe iod is unc ion o he o al mass o he sys em ela ed wi h he uid
37
densi y. The pe iods we e measu ed using a Keysigh 53220A uni e sal e-
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quency coun e , wi h
10−6
ms s anda d unce ain y o e pe iods a ound 4 ms.
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In Fig. 1 i is possible o see an example o expe imen al esul s o densi y as
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unc ion o p essu e o MEA + CO
2
mix u es wi h
α=0.15
mol
CO2
/mol
MEA
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Figu e 1: Expe imen al densi y as unc ion o p essu e o MEA + CO
2
mix u es:
α=0.15
mol
CO2
/mol
MEA
; a empe a u es: (
Ö
) 293.15 K; (
▲
) 313.15 K; (
⬩
) 333.15 K; (
•
) 353.15 K;
(
∆
) 373.15 K; (
◦
) 393.15 K. Lines ep esen he calcula ed alues using modied Tammann-
Tai equa ion.
Mix u es unce ain y analysis showed an expanded ela i e unce ain y be -
42
e han 0.3 % o a 95.5 % le el o condence.
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Densi y measu emen s o pu e MEA, pu e DEA, bina y sys ems MEA + CO
2
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and bina y sys ems DEA + CO
2
we e pe o med a p essu es om 0.1 MPa o
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70 MPa, six empe a u es anging om (293.15 K  393.15 K) o MEA bina y
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mix u es and ou empe a u es anging om (313.15 K  373.15 K) o DEA
47
2
bina y mix u es. In all cases, densi ies we e measu ed a h ee CO
2
loadings
48
α
= (0.15, 0.2 and 0.3) mol
CO2
/mol
amine
.
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3. Speed o sound measu emen s
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Speed o sound was measu ed using he adi ional double
pulse-echo
me hod.
51
This echnique is based on a di ec measu emen o he ansi ime o a pulse
52
signal, p opaga ing o e an independen ly known dis ance wi hin he uid.
53
This wo k p esen s speed o sound expe imen al esul s in samples o pu e
54
monoe hanolamine, and in mix u es o MEA + CO
2
in h ee die en con-
55
cen a ions, wi h
α
= (0.15, 0.20 and 0.30) mol
CO2
/mol
MEA
; besides o pu e
56
die hanolamine, and in wo bina y mix u es composed o DEA + CO
2
, wi h
57
α=(0.15
and
0.20)
mol
CO2
/mol
DEA
. Measu emen s we e ca ied ou in he
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empe a u e ange be ween 293.15 and 393.15 K and o se e al p essu es up o
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60 MPa, depending om he mix u es o pu e uid. In Fig. 2 i is possible o
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see he expe imen al speed o sound esul s as unc ion o p essu e o MEA +
61
CO
2
mix u e wi h
α=0.15
mol
CO2
/mol
MEA
.
62
Figu e 2: Expe imen al speed o sound as unc ion o p essu e o MEA + CO
2
mix u e wi h
α=0.15
mol
CO2
/mol
MEA
; (

) 313.15 K; (
◦
) 333.15 K; (
▲
) 353.15; (
▽
) 373.15 K.
The unce ain y o he speed o sound measu emen s was 0.33 % as maximum
63
alue, ob ained combining he con ibu ions o he unce ain ies o he quan i ies
64
used o de e mine i .
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3
4. Conclusion
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The p esen wo k, pa o a Eu opean P ojec Me ology Suppo o Ca -
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bon Cap u e U ilisa ion and S o age Me CCUS, aims o p o ide alida ed e -
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e ence measu emen s and ensu e he aceabili y o he esul s o he mophys-
69
ical pa ame e s o bina y mix u es o ca bon dioxide and amines. The au ho s
70
a e conden ha hese esul s will be use ul o de eloping a mo e ened and
71
accu a e o mula ion o a dedica ed equa ions o s a e.
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5. Acknowledgemen s
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The esea ch leading o hese esul s has ecei ed unding om he Eu opean
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Union on he basis o Decision No. 912/2009/EC in he ame o he EPM
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Me ology Suppo o Ca bon Cap u e U ilisa ion and S o age Me CCUS
76
(21GRD06 Me CCUS).
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