Profiles For Different Digestion Processes - Selecta DQO 6 Manual De Instrucciones

INSTRUCTION MANUAL CODE 80158 REV D
RAT controller executes temperature
"profiles", as a sequence of "steps"
defined with time and temperature.
J
.P. SELECTA s.a.u.
OCT/2019
6. Profiles for digestion process
The possibility of performing a process of digestion temperature profile has
several advantages, especially in the control of foam produced by the control
samples and smoke generation.
Control foam production.
The foam production during digestion has to be controlled, otherwise the foam
may overflow tube height of digestion and go outside, with two consequences:
• Damaging the block heater. (The foam contains sulfuric acid)
• Causing loss of sample.
The foam is caused by the moisture (water) sample. So the first step temperature
profile is dedicated to the removal of moisture (water) sample.
Control of production Smokes.
Fuming during digestion has to be controlled, otherwise these fumes, highly
acidic, are sent to the atmosphere.
The second step of the temperature profile is dedicated to smoke control.
The Kjeldahl digestion has an area of "white smoke" to 300 ° C.
Profile typical Kjeldahl digestion.
Step 1: 125º 30 'Extract moisture.
Step 2: 300° 30 'Checking white fumes.
Step 3: 400° 60 'ammonium mineralization.
• Dried Samples: Example: cereals: Step 1 may be 15 '
• Normal Samples: Example: Meat: Step 1 may be 30 '
• Samples "water": Example: residual waters: Step 1 may be 90 '
Examples of other "steps that may be necessary according to the sample:
• Low recovery of ammonium: Increase step 3
• Foam: Add a step to 150
• Excess smoke: add a step to 280.
Overall for better control, use more steps in the profile.
Profile for COD digestion.
Step 1: 150º 15 '
Step 2: 170° 60 'Digestion.
Profile Objective: providing a gentle rise in temperature.
Profile for hydrolysis (in determining fat SOXHLET).
Step 1: 150º 15 '
Step 2: 170° 60 ' Digestion.
Profile Objective: providing a gentle rise in temperature.
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