Selecta 4002627, Руководство пользователя

Страница: 37 / 48

MANUAL DE INSTRUCCIONES CÓDIGO 80187 REV D 01/2021 Pag.: 37
J
.P. SELECTA s.a.u. Autovía A-2 Km 585.1 Abrera 08630 (Barcelona) España Tel 34 937 700 877 Fax 34 937 702 362
e-mail: selecta@jpselecta.es - website: http://www.grupo-selecta.com
8 Checking the distiller (OQ)
Once the unit it is properly installed and the operator has acquired the knowledge to
work with it. The unit must be checked.
This process is known as Operation Qualification.
There are four basics checking to do:
8.1 Functional checking
Run this checking after installation and also for some maintenance.
Follow the instructions given on the chapter 5 to distillate for 5 minutes.
Verify the distillation rate. When the unit is at steady state distillation rate is be -
tween 30 - 40 ml per minute.
8.2 Checking Nitrogen Recovery.
This checking is widely used to certify that the unit works properly. Run some of
these tests for training purposes.
It consists to prepare some samples that have a known Nitrogen content. It is dis -
tilled, titrated and the nitrogen detected is calculated.
The rate (%) of nitrogen detected versus the sample Nitrogen content gives us the
Nitrogen Recovery .
To allow this checking, a 100gr ammonia sulphate flask is delivered together with
the distiller.
• Weight around 100mg (50mg reagent 0.1N) of ammonia sulphate. The exact
weight will be P
0
• The exact quantity of Nitrogen is: P
1
(mg) = P
0
x 0,212
• Distillate adding 25ml of NaOH
• Once distilling and titration, see 6.5, we obtain the detected nitrogen (mg) : P
2
P
2
(mg) = 14 x Volume
HCl
(ml) x Normality
HCl
• The recovery is calculated: R(%) = P
2
/ P
1
*100
• Acceptable values are from 99.0 to 101.5 %.
Note: Some literature sets that the acceptable values for recovery must be above
99.5%. To get this result you must work with high precision and use reagents with
high degree of purity.
8.3 Blank test.
This checking must be run on each batch in order to quantify the absence of am -
monia on the reagents.
It consists on distilling and titrating a sample of 25ml of distilled water.
Add 15ml of NaOH on the distillation.
Run some blank tests in order to get a constant value of blank. If this value is
repeated it could be subtracted from the detected Nitrogen.