Anton Paar GmbH Anton-Paar-Str. 20, 8054 Graz, Austria-Europe Internet: CarboQC Lab and at-line Beverage Carbonation Meter

Anton Paar GmbH Anton-Paar-Str. 20, 8054 Graz, Austria-Europe Internet: http://www.anton-paar.com

CarboQC

Lab and at-line Beverage Carbonation Meter


Contents of this presentation

Basics of CO2 analysis

Multiple Volume Expansion method

CarboQC Lab and at-line beverage carbonation meter


Basics of CO2 analysis

What are the fundamental laws involved?

How can the fundamental laws be applied to solve practical problems?

How is the CO2 solubility influenced and what are the consequences?


Fundamental gas lawsin beverage CO2 measurement

cco2 = ξco2 * pco2Henry’s law

ptot = pco2+ pAir + pH2O Dalton’s law

c … concentration ξ … absorption / solubility p … pressurem … mass M … molar mass V … volume R … gas constant Z … compression factor T … temp.

m = p*M*V/R*T*Z ‘Real’ gas law


CO2 measurement units

[g/l]Grams of CO2 per liter of liquid

Volumes [Vol.]Volumes of CO2 at 0°C and 1 atm diss. per liquid volume

1 Vol. = 1.976 g/l Conversion


Combining the fundamental laws: #1

What happens in a bottle/can/chamber?

p2*V2L* ξ 2 gas mass dissolved in liquid volume V2L

p2*V2G*M/(R*T2*Z2) gas mass in gas volume V2G

p1L*V1L* ξ 1 gas mass dissolved in liquid volume V1L

p1G*V1G*M/(R*T1G*Z1) gas mass in gas volume V1G

Initial state (1): before volume / temperature / solubility change no equilibrium or equilibrium between phases

Final state (2): after volume / temperature / solubility change equilibrium between phases


Combining the fundamental laws: #2 What happens in a bottle/can/chamber?

22222

1111111

2 *)**/(*

**)**/(**

LG

LLGGG

VZTRMV

VpZTRMVpp

2222002

111110011

2 *)*/(**

**)*/(***

LVZTZTV

LVpZTZTVpp

LG

LLGGG

p2 = ?

Gas solubility (Volumes of dissolved gas per volume of liquid

at standard conditions)

L = ξ / (M/(R*T0*Z0))

Equilibrium pressure in final state (2)


From: Rammert / Pahl,Brauwelt Nr. 12Nürnberg 1991

CO2 absorptioncoefficient /solubility isinfluenced by- temperature- sugar- acids & flavors- CO2 pressure- dissolved air - etc.

CO2 absorption coefficient


Non-equilibrium state at bottle/can filling

e.g. 10% headsp.

90%

liquid

volume

At filling: Most CO2

dissolved in beverage,little CO2 in headspaceif not actively enriched

Equilibrium: CO2

distributed approx.proportional to liquidto headspace ratio

Headspace:Cans: 3...5%Bottles: 5...12%

0.33 Vol.

3.32 Vol.

~100% CO2

e.g.

3.65 Vol.

~0% CO2


Headspace related temperature effect

10% gasvolume

90%

liquid

volume

CO2 dissolvedin beverageat 40°F / 4°C inequilibrium state:

CO2 dissolvedin same beverageat 70°F/ 21°C inequilibrium state:

Beveragecontainer:e.g. 10%headspace

0.40 Vol.

3.25 Vol.3.40 Vol.

0.25 Vol.


Multiple Volume Expansion Method

What happens to the gas partial pressures when the volume of the measuring chamber is expanded?

How and why does the Multiple Volume Expansion Method work?

What are the results?


CO2 and air equilibrium pressures as a function of volume expansion

0,0

0,2

0,4

0,6

0,8

1,0

1,2

0 10 20 30 40 50

% Volume expansion

arb

itra

ry p

ress

ure

un

its

CO2 pressure

Air pressure

The air pressure decreases excessively because the solubility of air is much lower than that of CO2 !


CO2 measurement w/o air compensation

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

0 10 20 30 40 50

% Volume expansion

CO

2 V

olu

me

s

0% air sat.


CO2 measurement w/o air compensation

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

0 10 20 30 40 50

% Volume expansion

CO

2 V

olu

me

s

0% air sat.

10% air sat.

20% air sat.

30% air sat.


CO2 error due to dissolved air

CO2 error due to dissolved air

0,00

0,05

0,10

0,15

0,20

0,25

0,30

0 10 20 30 40 50

% Volume expansion

Vo

l. C

O2

err

or

10% Air sat.

20% Air sat.

30% Air sat.


How does the Multiple Volume Expansion Method work?

A measuring chamber is completely filled with sample and sealed.

The volume of the measuring chamber is expanded.

Pressure and temperature equilibrium is generated.

Equilibrium pressure and temperature are measured.

The measuring chamber volume is further expanded, equilibrium is generated and pressure and temperature are again measured.

The two pressures/temperatures are used for CO2 determination and dissolved air compensation.


CarboQCMultiple Volume Expansion Method

1,00

1,02

1,04

1,06

1,08

1,10

0 10 20 30 40 50

% Volume expansion

CO

2 V

olu

me

s

1. measurement

deviation ?

correction !

2. measurement


Why does the Multiple Volume Expansion Method work?

The Multiple Volume Expansion method makes use of the fact that the solubility of CO2 is much higher than that of air.

By expanding the volume of the measuring chamber the partial pressures of CO2 and air change very differently.

Therefore CO2 and air partial pressures can be distinguished and the effect of dissolved air removed.


CarboQCMultiple Volume Expansion - Results

2,40

2,50

2,60

2,70

2,80

2,90

3,00

3,101 4 7

10

13

16

19

22

25

CO

2 [

v/v

]

0,00

0,50

1,00

1,50

2,00

2,50

3,00

3,50

4,00

DO

2 [

pp

m]

P/T (Calc.)

CO2 / CarboQC

DO2 [ppm]


CarboQC Lab and at-line beverage carbonation meter

New patented MVE Multiple Volume Expansion method

No influence from dissolved air

For accurate and traceable CO2 measurements


CarboQC

Measuring chamber

Display

Keypad


CarboQC Rear view


CarboQC

ON / OFF switch

Water-tight connection plug


CarboQC withsemi-automaticfilling device


Specifications of the CarboQC

Measuring range

0 to 12 g/l (0 to 6 Vol.) at 30°C (86°F)

0 to 20 g/l (0 to 10 Vol.) < 15°C (59°F)


Specifications of the CarboQC

Repeatability 0.005 bar (0.07 psia)0.05°C (0.1°F)0.01 g/l (0.005 Vol.)

Reproducibility 0.015 bar (0.21 psia)0.1°C (0.2 °F)0.05 g/l (0.025 Vol.)


Benefits of the CarboQC

No influence from dissolved air

Highly accurate absolute pressure sensor no weather and sea level influence

Very accurate temperature measurement due to impeller technique

No calibration/adjustment with reference methods or CO2 standards necessary

Zero point calibration simply with (tap) water

Small amounts of sample

Fast and accurate results in a wide temperature range

Versatile and easy to use with PFD filling device


Comparison to Zahm & Nagel results

Zahm & Nagel requires snifting (venting) at bottles to decrease air influence leads to temperature & headspace volume dependent loss of CO2

Zahm & Nagel is subject to full influence of air at cans due to no snifting being possible

Zahm & Nagel pressure and temperature measurement provides only limited accuracy

Headspace related temperature effect causes deviations

The CarboQC provides more precise results than Zahm & Nagel

CarboQC results are lower due to lack of air influence


Comparison to membrane-type instruments

Drift due to change of membrane permeability

Frequent recalibration necessary

Influenced by sample pressure and flow rate

Limited temperature range of calibration

Large amount of sample required

Reliable measurement, no drift

Virtually no calibration necessary

No influence of sample pressure and flow rate

Accurate results on cold and warm samples

Small amount of sample

CarboQC Membrane-type


CarboQC summary

Lab and at-line beverage carbonation meter

Patented Multiple Volume Expansion method No influence from dissolved air

Easy to use, fast and accurate

Wide measurement temperature range

Small amount of sample

Documents

Anton Paar GmbH Anton-Paar-Str. 20, 8054 Graz, Austria-Europe Internet: CarboQC Lab and at-line Beverage Carbonation Meter