Sampling and laboratory analysis are required to confirm that the process and
machinery are performing correctly. Without this, the equipment may be running
adequately, but the process may not be delivering the desired performance.
Also, in spite of the degree of instrumentation and automation installed, there is
always a need for laboratory analysis for several reasons. Some process variables
cannot be measured either very well, or at all, with on-line measurements. And all
instrumentation need verification methods, as they will drift or have other calibration
errors. Every operating department should have its own sampling and analysis
program to support the needs of the operator.
There are a number of recordings in the DCS-system for chemical, steam and dilution
dosages which are based on on-line measurements such as flow amount, consistency,
pH, temperature and levels of tanks and towers. If the on-line measurement differs
from actual situation, a dosage is going to be wrong or automation or monitoring
control is not working in the way that it should be.
With the help of laboratory analyses this kind of faulty action can be prevented and
analysis and measurement equipment can be calibrated to the right area or the DCS
system can be given a so called “adjustment factor”.
Comprehension and frequency of sampling and number of analyses depends upon the
number of operating and laboratory personnel and the department in question.
The analysis and sampling program for the DPA press should include: